The core of the Sun is considered to extend from the center to about 0.2 to 0.25 of
solar radius (). It is the hottest part of the Sun and of the Solar System. It has a density of 150000 kg/m3 (150 g/cm3) at the center, and a temperature of 15 million kelvins (15 million degrees Celsius, 27 million degrees Fahrenheit).

The core is made of hot, dense plasma (ions and electrons), at a pressure estimated at  (or 265 billion bar or 3.84 trillion psi at the center. Due to fusion, the composition of the solar plasma drops from 68 to 70% hydrogen by mass at the outer core, to 34% hydrogen at the core/Sun center.

The core inside 20% of the solar radius contains 34% of the Sun's mass, but only 0.8% of the Sun's volume. Inside 24% of the solar radius is the core which generates 99% of the fusion power of the Sun. There are two distinct reactions in which four hydrogen nuclei may eventually result in one helium nucleus: the proton–proton chain reaction – which is responsible for most of the Sun's released energy – and the CNO cycle.

Composition

The Sun at the photosphere is about 73–74% by mass hydrogen the rest being primarily helium, which is the same composition as the atmosphere of Jupiter, and the primordial composition of gases at the earliest star formation after the Big Bang. However, as depth into the Sun increases, fusion decreases the fraction of hydrogen. Traveling inward, hydrogen mass fraction starts to decrease rapidly after the core radius has been reached (it is still about 70% at a radius equal to 25% of the Sun's radius) and inside this, the hydrogen fraction drops rapidly as the core is traversed, until it reaches a low of about 33% hydrogen, at the Sun's center (radius zero). All but 2% of the remaining plasma mass (i.e., 65%) is helium.

Energy conversion

Approximately 3.7 protons (hydrogen nuclei), or roughly 600 million tonnes of hydrogen, are converted into helium nuclei every second releasing energy at a rate of 3.86 joules per second.

The core produces almost all of the Sun's heat via fusion: the rest of the star is heated by the outward transfer of heat from the core. The energy produced by fusion in the core, except a small part carried out by neutrinos, must travel through many successive layers to the solar photosphere before it escapes into space as sunlight, or else as kinetic or thermal energy of massive particles. The energy conversion per unit time (power) of fusion in the core varies with distance from the solar center. At the center of the Sun, fusion power is estimated by models to be about 276.5 watts/m3. Despite its intense temperature, the peak power generating density of the core overall is similar to an active compost heap, and is lower than the power density produced by the metabolism of an adult human. The Sun is much hotter than a compost heap due to the Sun's enormous volume and limited thermal conductivity.

The low power outputs occurring inside the fusion core of the Sun may also be surprising, considering the large power which might be predicted by a simple application of the Stefan–Boltzmann law for temperatures of 10 to 15 million kelvins. However, layers of the Sun are radiating to outer layers only slightly lower in temperature, and it is this difference in radiation powers between layers which determines net power generation and transfer in the solar core.

At 19% of the solar radius, near the edge of the core, temperatures are about 10 million kelvins and fusion power density is 6.9 W/m3, which is about 2.5% of the maximum value at the solar center. The density here is about 40 g/cm3, or about 27% of that at the center. Some 91% of the solar energy is produced within this radius. Within 24% of the radius (the outer "core" by some definitions), 99% of the Sun's power is produced. Beyond 30% of the solar radius, where temperature is 7 million K and density has fallen to 10 g/cm3 the rate of fusion is almost nil.

There are two distinct reactions in which 4 H nuclei may eventually result in one He nucleus: "proton–proton chain reaction" and the "CNO cycle" (see below).

Proton–proton chain reaction

The first reaction in which 4 H nuclei may eventually result in one He nucleus, known as the proton–proton chain reaction, is:

This reaction sequence is thought to be the most important one in the solar core. The characteristic time for the first reaction is about one billion years even at the high densities and temperatures of the core, due to the necessity for the weak force to cause beta decay before the nucleons can adhere (which rarely happens in the time they tunnel toward each other, to be close enough to do so). The time that deuterium and helium-3 in the next reactions last, by contrast, are only about 4 seconds and 400 years. These later reactions proceed via the nuclear force and are thus much faster. The total energy released by these reactions in turning 4 hydrogen atoms into 1 helium atom is 26.7 MeV.

CNO cycle

The second reaction sequence, in which 4 H nuclei may eventually result in one He nucleus, is called the CNO cycle and generates less than 10% of the total solar energy. This involves carbon atoms which are not consumed in the overall process. The details of this CNO cycle are as follows:

This process can be further understood by the picture on the right, starting from the top in clockwise direction.

Equilibrium

The rate of nuclear fusion depends strongly on density. Therefore, the fusion rate in the core is in a self-correcting equilibrium: a slightly higher rate of fusion would cause the core to heat up more and expand slightly against the weight of the outer layers. This would reduce the fusion rate and correct the perturbation; and a slightly lower rate would cause the core to cool and shrink slightly, increasing the fusion rate and again reverting it to its present level.

However the Sun gradually becomes hotter during its time on the main sequence, because the helium atoms in the core are denser than the hydrogen atoms they were fused from. This increases the gravitational pressure on the core which is resisted by a gradual increase in the rate at which fusion occurs. This process speeds up over time as the core gradually becomes denser. It is estimated that the Sun has become 30% brighter in the last four and a half billion years and will continue to increase in brightness by 1% every 100 million years.

Energy transfer

The high-energy photons (gamma rays) released in fusion reactions take indirect paths to the Sun's surface. According to current models, random scattering from free electrons in the solar radiative zone (the zone within 75% of the solar radius, where heat transfer is by radiation) sets the photon diffusion time scale (or "photon travel time") from the core to the outer edge of the radiative zone at about 170,000 years. From there they cross into the convective zone (the remaining 25% of distance from the Sun's center), where the dominant transfer process changes to convection, and the speed at which heat moves outward becomes considerably faster.

In the process of heat transfer from core to photosphere, each gamma photon in the Sun's core is converted during scattering into several million visible light photons before escaping into space. Neutrinos are also released by the fusion reactions in the core, but unlike photons they very rarely interact with matter, so almost all are able to escape the Sun immediately. For many years measurements of the number of neutrinos produced in the Sun were much lower than theories predicted, a problem which was recently resolved through a better understanding of neutrino oscillation.

See also
 Active region
 Stellar core

References

External links
 Animated explanation of the core of the Sun (University of South Wales).
 Core of the Sun (University of South Wales).
 Animated explanation of the temperature and density of the core of the Sun (University of South Wales).

Sun

Solar core


Lymphopoiesis (lĭm'fō-poi-ē'sĭs) (or lymphocytopoiesis) is the generation of lymphocytes, one of the five types of white blood cells (WBCs). It is more formally known as lymphoid hematopoiesis.

Disruption in lymphopoiesis can lead to a number of lymphoproliferative disorders, such as lymphomas and lymphoid leukemias.

Terminology

Lymphocytes are of the lymphoid (rather than the myeloid or erythroid) lineage of blood cells.

Nomenclature is not trivial in this case, because, although lymphocytes are found in the bloodstream and originate in the bone marrow, they principally belong to the separate lymphatic system which interacts with the blood circulation.

Lymphopoiesis is now usually used interchangeably with the term "lymphocytopoiesis" – the making of lymphocytes – but some sources distinguish between the two, stating that "lymphopoiesis" additionally refers to creating lymphatic tissue, while "lymphocytopoiesis" refers only to the creation of cells in that tissue. It is rare now for lymphopoiesis to refer to the creation of lymphatic tissues.

Myelopoiesis refers to "generation of cells of the myeloid lineage" and erythropoiesis refers to "generation of cells of the erythroid lineage", so parallel usage has evolved in which lymphopoiesis refers to "generation of cells of the lymphoid lineage".

Observations on research going back well over 100 years had elucidated the two classes of WBCs – myeloid and lymphoid – and advances in medicine and science have resulted from these studies. After investigating the origins of these two classes of cells, scientists isolated and defined two cell types with some strong stem cell properties – the common myeloid progenitor (CMP) and the common lymphoid progenitor (CLP) for mice. It was eventually found these progenitors were not unique, and that the myeloid and lymphoid classes were not disjoint, but rather two partially interwoven family trees.

Function

Mature lymphocytes are a critical part of the immune system that (with the exception of memory B and T cells) have short lives measured in days or weeks and must be continuously generated throughout life by cell division and differentiation from cells such as common lymphoid progenitors (CLPs) in mice.

The set comprising CLP cells and similar progenitors are themselves descendants of the pluripotential hemopoietic stem cell (pHSC) which is capable of generating all of the cell types of the complete blood cell system. Despite their ability to generate the complete suite of lymphocytes, most progenitors are not true stem cells, however, and must be continually renewed by differentiation from the pHSC stem cell.

Many progenitor cells are also referred to as transit cells, sometimes also called transit amplifying cells, the meaning of this term being that the transit cell may found a new sub-lineage but the number of resultant cells is strictly limited (although possibly very large, even trillions yet finite) and the lineage is terminated by cells that die off (by apoptosis) or remain as cells that can no longer divide. Examples of such cells are CFUs (Colony-forming units – referred to as such because of their ability to form colonies in vitro in artificial media) such as CFU-T.

In mice, transplantation of a single pHSC cell can reconstitute a sub-lethally irradiated host (i.e. a mouse that has been irradiated so that all leukocytes are killed) with all these lineages of cells, including all types of lymphocytes via CLPs. This has been known for more than 40 years.

Lymphopoiesis continues throughout life and so progenitor cells and their parent stem cells must always be present.

Overview

In the case of mammals such as humans (Homo sapiens), lymphopoiesis begins with limited passive provision by the mother of lymphocytes and substantial immunoglobulin G that cross the placenta and enter the fetus to provide some protection against pathogens, and also leukocytes that come from breast milk and enter circulation via the digestive tract. It is often not effective in preventing infections in the newborn.

However, early in gestation, the developing embryo has begun its own lymphopoiesis from the fetal liver. Lymphopoiesis also arises from the yolk sac. This is in contrast to the adult where all lymphocytes originate in the bone marrow.

There are four major types of lymphocytes, many sub-types, and hundreds or thousands of lymphocyte cell types that have been identified by scientists. All are generated by normal or abnormal lymphopoiesis except for certain artificial strains created in the laboratory by development from existing strains. Although lymphocytes are usually considered mature (as seen in blood tests) they are certainly not inert but can and do get around the body to anywhere there is a need; and when such need arises, new rounds of 'downstream' lymphopoiesis such as cell multiplication and differentiation may arise, coupled with intense mitotic and metabolic activity.

This is hardly a simple topic. In his 1976 text Immunology, Aging and Cancer immunologist and Nobel Prize winner Sir Frank Macfarlane Burnet speculated that the immune system might one day be found to be as complex as the nervous system. As the production of lymphocytes is so close to the central role of the immune response it is wise to approach the study of it with some humility in the face of the task, although there are general principles that help in understanding.

Process

Lymphopoiesis can be viewed in a mathematical sense as a recursive process of cell division and also as a process of differentiation, measured by changes to the properties of cells.
 Given that lymphocytes arise from specific types of limited stem cells – which we can call P (for Progenitor) cells – such cells can divide in several ways. These are general principles of limited stem cells.

Considering the P as the 'mother' cell, but not a true stem cell, it may divide into two new cells, which are themselves identical, but differ to some degree from the mother. Or the mother cell P may divide unequally into two new daughter cells both of which differ from each other and also from the mother.

Any daughter cell will usually have new specialized abilities and if it is able to divide it will form a new sub-lineage. The difference of a daughter cell from the mother may be great, but it could also be much less, even subtle. What the P mother cell does not do is divide into two new P mother cells or a mother and a daughter; this is a matter of observation as such limited progenitor cells are known to not self-renew.
 There is a sort of exception when daughter cells at some level of the lineage may divide several times to form more seemingly identical cells, but then further differentiation and division will inevitably occur, until a final stage is reached in which no further division can occur, and the cell type lineage is finally mature. An example of maturity is a plasma cell, from the B cell lineage, which produces copious antibody, but cannot divide and eventually dies after a few days or weeks.
 The progenitor CLP of the mouse or the progenitor MLP of the human differentiates into lymphocytes by first becoming a lymphoblast (Medical Immunology, p.10). It then divides several more times to become a prolymphocyte that has specific cell-surface markers unique to either a (1) T cell or (2) B cell. The progenitor can also differentiate into (3) natural killer cells (NKs) and (4) dendritic cells (DCs).
 T cells, B cells and NK cells (and all other Innate lymphoid cells) are unique to the lymphocyte family, but dendritic cells are not. DCs that are of identical appearance but have different markers are spread throughout the body, and come from either lymphoid and myeloid lineages, but these cells may have somewhat different tasks and may take up lodging preferentially in different locations.  (Revise in light of new research) This is now an open question; also, the different dendritic cell lineages may have different 'tasks' or functions, and stay in different 'locations.'

T and B lymphocytes are indistinguishable under the microscope. The inactive B and T cells are so featureless with few cytoplasmic organelles and mostly inactive chromatin that until the 1960s textbooks could describe these cells, now the central focus of immunology, as having no known function!

However T and B lymphocytes are very distinct cell lineages and they 'grow up' in different places in the body. They perform quite different (although co-operative) functions in the body. No evidence has ever been found that T and B cells can ever interconvert. T and B cells are biochemically distinct and this is reflected in the differing markers and receptors they possess on their cell surfaces. This seems to be true in all vertebrates, although there are many differences in the details between the species.
 Regardless of whether the CLP (mouse) or MLP or a small closely related set of progenitor cells take credit for generating the profusion of lymphocytes, the same lymphoid progenitors can still generate some cells that are clearly identifiably myeloid.

Lymphopoiesis for T cells

T cells are formed in bone marrow then migrate to the cortex of the thymus to undergo maturation in an antigen-free environment for about one week where a mere 2–4% of the T cells succeed. The remaining 96–98% of T cells die by apoptosis and are phagocytosed by macrophages in the thymus. So many thymocytes (T cells) die during the maturation process because there is intensive screening to make sure each thymocyte has the ability to recognize self-peptide:self-MHC complex and for self tolerance. The apoptosed thymocyte dies and is quickly recycled.

Upon maturity, there are several forms of thymocytes including
 T-helper (needed for activation of other cells such as B cells and macrophages),
 T-cytotoxic (which kill virally infected cells),
 T-memory (T cells that remember antigens previously encountered), and
 T-suppressor cells (which moderate the immune response of other leukocytes). Also called T-regulatory cells (Treg)

When T cells become activated they undergo a further series of developments. A small, resting T lymphocyte rapidly undergoes blastogenic transformation into a large lymphocyte (13–15 μm).  This large lymphocyte (known in this context as a lymphoblast) then divides several times to produce an expanded population of medium (9–12 μm) and small lymphocytes (5–8 μm) with the same  antigenic specificity. Final activated and differentiated T lymphocytes are once again morphologically indistinguishable from a small, resting lymphocyte. Thus the following developmental states may be noticed in sequence in blood tests:
 Prolymphocyte
 Large lymphocyte
 Small lymphocyte

Basic Map of T Cell lymphopoiesis

This basic map of T Cell formation in sequence, is simplified and is akin to textbook descriptions, and may not reflect latest research.(Medical Immunology, p. 119)

In the thymus
 MLP
 ETP
 DN1
 (B; Mφ)
 DN2
 (DC; NK)
 DN3
 (γδ)
 DN4
 DP
 (TNK; CD4; CD8; Treg)

In the Periphery
 (Th1; Th2)

T cell development

Unlike other lymphoid lineages, T cell development occurs almost exclusively in the thymus. T-lymphopoiesis does not occur automatically but  requires signals generated from the thymic stromal cells. Several stages at which specific regulators and growth factors are required for T cell development to proceed have been defined. Later in T cell development and its maturation these same regulatory factors again are used to influence T cell specialization.

T cells are unique among the lymphocyte populations in their ability to further specialize as mature cells and become yet more mature. And T cells come in many flavors, for example: the conventional TcRαβ T cells; the so-called unconventional TcRγδ T cells; NKT cells; and T regulatory cells (Treg).  Details regarding the developmental and life cycle of the unconventional T cells are less well-described compared to the conventional T cells.

Stages of T cell maturation

Stage One: Thymic Migration

Multipotent lymphoid progenitors (MLP) enter the T cell pathway as they immigrate to the thymus. The most primitive cells in the thymus are the early thymocyte progenitors (ETP), which retain all lymphoid and myeloid potential but exist only transiently, rapidly differentiating into T and NK lineages. (Medical Immunology, p. 118)

Stage Two: Proliferative Expansion and T Lineage Commitment

Final commitment to the T cell lineage occurs within the thymic microenvironment, the microscopic structures of the thymus where T cells are nurtured. The most primitive T cells retain pluripotential ability and can differentiate into cells of the myeloid or lymphoid lineages (B cells, DC, T cells, or NK cells).

More differentiated double negative T cells (DN2 cells) have more limited potentiality but are not yet fully restricted to the T cell lineage (they can still develop into DC, T cells, or NK cells). Later on, they are fully committed to the T cell lineage- when thymocytes expressing Notch1 receptors engage thymic stromal cells expressing Notch1 ligands, the thymocytes become finally committed to the T-cell lineage. See Gallery Image "Double Negatives"

With the commitment to the T cell lineage, begins a very complex process known as TCR gene rearrangement. This creates an enormous diversity of T cells bearing antigen receptors. Afterward some T cells leave the thymus to migrate to the skin and mucosae.

Stage Three: β-Selection

Stage Four: T Cell Receptors Selection

Only 2% to 3% of the differentiating thymocytes, those that express TcR capable of interaction with MHC molecules, but tolerant to self-peptides,  survive the Stage Four selection process.

Stage Five: Continuing Differentiation in the Periphery

It was previously believed that the human thymus remained active as the site of T cell differentiation only until early adulthood and that later in adult life the thymus atrophies, perhaps even vanishing. Recent reports indicate that the human thymus is active throughout adult life. Thus several factors may contribute to the supply of T cells in adult life: generation in the thymus, extra-thymic differentiation, and the fact that memory T cells are long-lived and survive for decades.

T cell types
 Unconventional T cells
The thymus also gives rise to the so-called 'unconventional T cells' such at γδ T cells, natural killer T cells (NKT) and regulatory T cells (Treg).
 γδ T cells
γδT cells  represent only 1% to 5% of the circulating T cells, but are abundant in the mucosal immune system and the skin, where  they represent the dominant T cell population. These 'non-MHC restricted T cells' are involved in specific primary immune responses, tumor surveillance, immune regulation and wound healing.

Several differences between αβ and γδ T cell development have been described. They emigrate from the thymus in "waves" of clonal populations, which home to discrete tissues. For example, one kind is found in the peripheral blood while another predominates in the intestinal tract.
 Natural Killer T cells
Human NKT cells are a unique population and are thought to play an important role in tumor immunity  and immunoregulation.
 T Regulatory cells
Treg cells are considered as naturally occurring regulatory T cells. Tregs comprised about 5% of the circulating CD4+ T cells. These cells are thought to possess an important autoimmunity property by regulating 'autoreactive' T cells in the periphery. (Medical Immunology, p. 117-122)

Lymphopoiesis for B cells

B cells are formed and mature in bone marrow (and spleen).

It is a good mnemonic aide that B cells are formed in the bone marrow, but it is a mere coincidence since B cells were first studied in the chicken's bursa of Fabricius and it is from this bursa that B cells get their name.

These B cells then leave the bone marrow and migrate via bloodstream and the lymph to peripheral lymphoid tissues, such as a spleen, lymph nodes, tonsils and mucosal tissues. Once in a secondary lymphoid organ the B cell can be introduced to an antigen that it is able to recognize.

Through this antigen recognition and other cell interactions the B cell becomes activated and then divides and differentiates to become a plasma cell. The plasma cell, a B cell end product, is a very active antibody-secreting cell that helps protect the body by attacking and binding to antigen.

Even after many decades of research, some controversy remains as to where B cells mature and 'complete their education', with the possibility remaining that the site may also partially be peri-intestinal lymphoid tissues.

B lymphopoiesis occurs exclusively in the bone marrow and B lymphocytes are made continuously throughout life there in a 'microenvironment' composed of stromal cells, extracellular matrix, cytokines and growth factors, which are critical for proliferation, differentiation, and survival of early lymphocyte and B-lineage precursors.

The relative proportion of precursor B cells in the bone marrow remains rather constant throughout the life span of an organism. There are stages such as Pre-B-I cells (5% to 10% of the total); Pre-B-II cells (60% to 70%) while the remaining 20% to 25% are immature B cells.  Most textbooks say that B Cells mature in the bone marrow but, generally, immature B cells migrate to the spleen for 'higher education' of some sort where they go through  transitional stages before final maturation.(Medical Immunology, p. 136)

B lymphocytes are identified by the presence of soluble immunoglobulin G (IgG). This is the most common protective immunoglobulin in the adult body. After antigenic stimulation, B cells differentiate into plasma cells that secrete large quantities of soluble IgG. This is the final stage of B lymphopoiesis but it is the clincher because the plasma cells must either issue antibody close to a source of infection, or disseminate it in the blood to fight an infection at a distance or in an inaccessible part of the body.

Basic map of B cell lymphopoiesis

A generally regarded valid map of B cell lymphopoiesis is as follows in sequence, in two parts with the first being in the bone marrow and the second in the spleen:. The development process in the bone marrow occurs in germinal centers

In the bone marrow
 Pro-B
 Pre-B-I
 Pre-B-II large
 Pre-B-II small
 Imm(ature)

In the spleen
 T1
 T2/T3
 (Marginal Zone (MZ); B-1; B-2)
 B-2 further differentiate into:
 (Germinal Center (GC); Memory; Plasma )

Lymphopoiesis for NK cells

NK cells, which lack antigen specific receptors, develop in the bone marrow. After maturation and release from the marrow they circulate in the blood through their lifetime seeking opportunity. The opportunity they seek is to encounter and recognize and then kill abnormal cells such as cancer or virally infected cells. It is well known that lymphocytes never have granules or at least not granules that are readily visible even upon staining. However NK cells are the exception. They do have numerous granules which provide their ability to kill cells and these granules are why NK cells have an alternate name-  Large Granular Lymphocytes (LGLs).

NK cells are the only lymphocytes considered part of the innate immune system (in contrast to the adaptive immune system. Yet they are much more closely related to T cells (part of the adaptive immune system) than to other cells of the innate immune system. NK cells not only share many surface markers, functions and activities in common  with  T  Cells, they also  arise  from  a common T/NK progenitor.  The T/NK  precursor is also believed to be the source of a subpopulation of lymphoid DC. (Medical Immunology, p. 121)

NK cells have a definition 'barcode' as CD3, CD16+, CD56t lymphocytes. (See Barcode Section of this article). NK progenitors can be found mainly in the thymus (mouse), but the thymus is not absolutely required for NK development.  Probably NK cells can develop in a variety of organs but the major site of NK cell development is not known.

In humans, the majority (85–90%) of the NK cells have a high cytolytic capacity (the ability to lyse cells). A smaller subset (10–15%) called NK 'CD56 bright' is chiefly responsible for cytokine production and has enhanced survival. Traveling to lymph nodes the 'CD56 bright' NK cells differentiate again into mature NK cells which express killer cell immunoglobulin-like receptors (KIR), natural cytotoxicity receptors (NCR), and critical adhesion molecules. (Medical Immunology, p. 122)

Lymphopoiesis for dendritic cells

The process by which CLP cells may differentiate to generate dendritic cells of lymphoid lineage is not yet well defined.

DCs are highly specialized and efficient antigen-presenting cells. Cells identical in appearance come both from a myeloid lineage (referred to as myeloid dendritic cells) and also from a lymphoid lineage (referred to as plasmacytoid dendritic cells).

The development and regulation of DC is not well-characterized. While the DC precursors have been identified in the human fetal liver, thymus, and bone marrow, during adult life DC are thought to be produced only from the bone marrow and released into the blood to wander and settle down. Overall a large number of DC of varying types are dispatched throughout the body, especially at epithelia such as skin, to monitor invaders and nibble their antigens. (Medical Immunology, p. 122)

Comparison of killers from lymphopoiesis

Lymphocytes have a number of alarming properties such as the ability to wander around the body and take up lodging almost anywhere, and while on the way issue commands in the form of cytokines and chemokines and lymphokines, commands that affect many cell types in the body and which may also recursively induce further lymphopoiesis. One strong behavior pattern that captivates researchers and the public alike is the ability of lymphocytes to act as police, judge and executioner to kill other cells or demand that they suicide, a command that is usually obeyed. There seems to be no other sentencing option available.

Killers are distinguished from cells such as macrophages that eat other cells or munch debris by a method called phagocytosis. Killers do not use phagocytosis, they just kill and leave the clean-up to other cells.

Killers are known to attack virus-infected cells and cells that have become cancerous. Because of these abilities much research has been done into transforming these qualities into medical therapy but progress has been slow.

Here is the parade of killers and how they work:
 Cytotoxic T cells
(also called Tc or antigen-specific cyto -lytic or -toxic T lymphocytes (CTL)). Tc kill by apoptosis and either splash their target with perforin or granzymes or else use Fas-Fasl Interaction to command target elimination. This kills cells that are infected and display antigen.
 NK cells (also called LGL (large granular lymphocytes))
These kill with exactly the same methods as Tc, but have no interaction with any antigen. They select their targets based on typical molecules displayed by cells that are under stress by viral infection. NK Cells mainly are in the circulation (5-15% of the circulating lymphocytes) yet are also distributed in tissues everywhere.
 LAK cells (Lymphokine-activated killer) are a laboratory/clinical subset of NK Cells promoted by IL-2 to attack tumor cells.
 NKT cells  see Natural Killer T cell main article
Natural Killer T Cells. Human NK T cells are a unique population (which express NK cell markers such as CD56 and KIR). NKT cells are thought to play an important role in tumor immunity and immunoregulation. (Medical Immunology, p. 135), yet little is known. Recent evidence suggests a role working together with hepatic stellate cells being a liver-resident antigen-presenting cell that presents lipid antigens to and stimulates proliferation of NKT cells.
 Natural killer-like T cells
A heterogeneous group with ill-defined properties.

However, in summary there is no known cell or set of cells that is capable of killing cancerous cells in general.

Labeling lymphopoiesis

Because all WBCs are microscopic, colorless and often seemingly identical in appearance they are individually identified by their natural chemical markers, many of which have been analyzed and named. When two cells have the same markers, the reasonable assumption is made that the cells are identical at that time.  A set of markers is colloquially described as the barcode for that cell or that cell line.
 Here is an example of how a barcode can come to be, for the all-important hematopoietic stem cell (HSC) as an example.

HSCs are technically described as: lacking FMS-like tyrosine kinase 3 (Flt3) and lacking the markers specific to discrete lymphoid lineages (Lin), but expressing high levels of Sca1 and c-kit; HSC also express CD44, low levels of Thy1.1 (CD90), but no IL-7Ra or CD27.

This is called the (surface) phenotype of an HSC. It can be expressed as a set (Lin2, Sca1high, c-kit high, CD44+, Thy1.1low, CD27 2, and IL-7Ra2). This set is a 'barcode' for the HSC, akin to the barcode label attached to your chicken-wing plastic bag for checkout at a supermarket! Scientists use these barcodes to check, categorize and accumulate cells for many purposes often using laboratory methods such as cell flow cytometry. These barcodes partially define the modern meaning of phenotype for leukocytes.

Progression of HSC differentiation and lineage commitment is indicated by changes in this phenotype. That is, as the cell changes, the markers will also change and the barcode will change.
 Typical barcodes for some cell types appearing in this article.

 Note explaining the barcode parameter details: Flt3 is a cytokine tyrosine kinase receptor thought to be important in early lymphoid development. In addition, Flt3 plays a major role in maintaining B lymphoid progenitors. CD27 plays a role in lymphoid proliferation, differentiation, and apoptosis. The acquisition of CD27 and Flt3 by the HSC coincides with the loss of long-term repopulating potential. At this stage the cells retain both lymphoid and myeloid potential and are referred to as multipotent progenitors. (Medical Immunology, p. 114)

Knowledge development regarding lymphopoiesis

New questions emerge in immunology continuously as though there were a stem cell for questions. For example, it was thought that the process of lymphopoiesis was a direct, orderly unidirectional sequence. But it is not clear  if end-stage lymphocytes come from progenitors that are homogeneous populations or overlapping populations. Nor is it clear whether lineages of lymphocytes develop via a continuum of differentiation with a progressive loss of lineage options or whether abrupt events result in the acquisition of certain properties.

Changes in cytoplasm, morphology of the cell nucleus, granules, cell internal biochemistry, signaling molecules and cell surface markers are difficult to correlate with definite stages in lymphopoiesis. The morphological differences do not just correspond to steps in mitosis (somatic cell division), but result from continuous "maturation processes"of the cell nucleus as well as of the cytoplasm and so one must not be too rigid about morphological distinctions between certain cell stages.
 Models and updates on the lymphopoiesis family tree

Until recently the model of the CMP generating all myeloid cell and the CLP generating all lymphoid cells was considered necessary and sufficient to explain the known facts observed in the generation of WBCs, and it is still found in most basic textbooks. However beginning around 2000 and gaining momentum after 2005 in both studies in humans and mice, new complexities were noted and published in papers. These studies are important now mainly to immunology researchers but are likely to eventually lead to changes in medical treatments.

The changes were sparked by observations that lymphopoiesis did not always break into two lineages at the level of the CLP. Worse, some macrophages (long considered a myeloid lineage) could be generated by lymphoid lineage progenitors. In essence focus has been shifted away from the CLP to the MLP (lymphoid-specified progenitors), which are clearly lymphoid progenitors yet retain some myeloid potential, particularly the ability in both humans and mice to make macrophages – one of the most versatile of immune cell defenders – and also many dendritic cells, the best 'watchdogs' of antigen invaders.

However, whatever the details may turn out to be, the process of lymphopoiesis always seems to relentlessly give rise to progeny with special attributes and abilities – "superpowers" so to speak – but with progressively more restricted lymphoid developmental potential.

Stages of development

The old model: lymphoid vs myeloid
This model of lymphopoiesis had the virtue of relative simplicity, agreement with nomenclature and terminology, and is still essentially valid for the laboratory mouse.
 pHSC pluripotent, self-renewing, hematopoietic stem cells  which give rise to
 MPP   multipotent progenitors, which give rise to
 ELP   (or PRO) Prolymphocytes, early lymphoid progenitors, and finally to the
 CLP   Common lymphoid progenitor, a cell type fully committed to the lymphoid lineage.

pHSC, MPP and ELP cells are not fully committed to the lymphoid lineage because if one is removed to a different location it may differentiate into non-lymphoid progeny. However CLP are committed to the lymphoid lineage. The CLP is the transit cell responsible for these (generally parallel) stages of development, below:
 NK cells
 Dendritic cells (lymphoid lineage; DC2 )
 Progenitor B cells
 Pro-B cells => Early Pro (or pre-pre)-B cells => Late Pro (or pre-pre)-B cells
 Large Pre-B cells => Small Pre-B cells
 Immature B cells
 B Cells => (B1 cells; B2 cells)
 Plasma cells
 Pro-T cells
 T-cells

Research on new models (not mice)
By 2008 it was found that "the majority of early thymic progenitor [ETP] cells do not commit to becoming T cells by the time they get to the thymus gland. ETP cells retained the ability to become either T cells or myeloid cells."

See also :

Graphical view of the old model vs mixed myelo-lymphoid model

General immunology reference texts

Texts in bold are the most heavily cited in this article.
 Cell Communication in Nervous and Immune System; Gundelfinger, Seidenbecher, Schraven; Springer Berlin Heidelberg New York; 2006;
 Color Atlas of Hematology; Theml et al.; Thieme; 2004;
 Dynamics of Cancer; Steven A. Frank; Princeton University Press, Princeton, New Jersey; 2007; , Creative Commons Public License
 Fundamental Immunology, 5th edition; William E. Paul (Editor); Lippincott Williams & Wilkins Publishers; 2003;
 Immuno-Biology: The Immune System in Health and Science, 6th Edition; Janeway, Travers; 2005; Garland Science Publishing, New York;
 Immunology Introductory Textbook (ebook;revised 2nd edition); Nandini Shetty; New Age International (P) Limited, Publishers, India; 2005;
 Instant Notes in Immunology, 2nd ed.; Lydyard, Whelan, Fanger; Taylor and Francis Group; 2004; China Version ; 46RMB Wangfujing Bookstore
 Medical Immunology—6th ed.; G. Virella, Editor; Informa Healthcare USA, Inc; 2007;
 Stem Cell Biology; Marshak, Gardner, Gottlieb; Cold Spring Harbor Laboratory Press; 2001; /01
 Textbook of Human Development and Histology; Zhong Cuiping et al.; Shanghai Scientific and Technical Publishers; 2006;
 Textbook of Medical Immunology (Immunology, 7th Edition); LIM Pak Leong; Elsevier (Singapore) Pte Ltd.; 2006;

References

Additional images
Alternate views of lineages

External links
  The www.copewithcytokines.de Mini-portal to Lymphopoiesis terminology

 Overview at hematologica.pl

Lymphology
Lymphocytes
Hematopoiesis
Histology

fr:Leucopoïèse

Lymphopoiesis


Mat Hoffman's Pro BMX 2 is a BMX video game endorsed by Mat Hoffman and published by Activision under the Activision O2 label. The game, which serves as a sequel to Mat Hoffman's Pro BMX, was released on August 13, 2002 for the PlayStation 2 and Xbox. A Game Boy Advance port was developed by HotGen and released the same day as the PlayStation 2 and Xbox versions. A GameCube port was developed by Gratuitous Games and was released on October 8, 2002.

Gameplay
Like its predecessor, Mat Hoffman's Pro BMX 2 uses the basic game structure carried over from Activision's Tony Hawk's Pro Skater series of video games. The goal of the game is to successfully perform and combine different tricks on a BMX bike, with successful executions adding to the player's score. The point value of the trick is based on time maintained, degrees rotated, number of tricks performed in sequence, and the number of times the tricks have been used (the more often a trick is used, the less it's worth). Successful tricks also add to the player's special meter, which, once full, allows for the execution of "signature moves" which are worth more than normal tricks. Grinds, lip tricks, and manuals (wheelies) are included in the game to help the player link tricks together into combos. Bails (falling off the bike due to poor landing) cause for no points to be awarded for the attempted trick or combo, and resets the special bar to empty.

Enhancements over the previous installment include improved graphics, new tricks (including flatland tricks and a "trick tweaking system", similar to the trick modifier featured in Dave Mirra Freestyle BMX), a balance meter for grind and lip tricks, more riders, a longer career mode, a larger soundtrack, and larger, more interactive environments.

The player can choose from eleven different professional BMX riders, with each rider having their own unique stats, bikes, and trick sets. Eight levels are included in the game, set in and around various cities across the United States. The Xbox version features a total of twelve professional BMX riders and nine levels: rider Chad Kagy and the London level are exclusive to this release.

Game modes
Road Trip — "Road Trip" is the equivalent to the previous game's "Career Mode". In this mode, the player has to complete different tasks (such as getting a high score or collecting items) in an attempt to earn points and advance to new levels. Each level has twelve goals to complete (as opposed to five in the first game), broken up into three categories based on difficulty. Only four goals are available at one time, which must be completed before unlocking the next set of challenges. Advancing in this mode allows the player to unlock new levels, bikes, riders, and songs from the game's soundtrack. Videos are also unlocked which includes over 90 minutes of footage from a real BMX tour featuring the pros, which promoted the game.

Session —  In this mode, the player chooses a BMX rider, an available bike, an available level, and rides for a one to five-minute session in an attempt to set a high score.

Free Ride — Free Ride is similar to the Session mode; the player chooses a BMX rider, an available bike, and an available level. Instead of a timed session, however, there is no time limit, allowing the player to practice or simply explore, searching for gaps and secrets areas.

Tiki Battle — After completing the Road Trip mode, a bonus game is unlocked, called the "Tiki Battle", which acts as a first person shooter. The player attempts to defeat a large animated statue located in the Hawaii level of the game, collecting ammunition and health bonuses while avoiding fireballs thrown at the player. When this challenge is completed, a special character is unlocked and the "Tiki Battle" becomes available in the main menu of the game.

Multiplayer modes — The game features several new and returning multi-player modes including Horse, Trick Attack, Graffiti, Tag, and Push.

Course Editor — This mode allows the player to create their own level by arranging various ramps, rails, and other pieces. Gaps can be created and named, and the player's starting positions can also be chosen by the player. Once a created park is finished, the level can be accessed in the game's "Session", "Free Ride", and multiplayer modes.

Reception

The game received "generally favorable reviews" on all platforms except the GameCube version, which received "average" reviews, according to video game review aggregator Metacritic.  In Japan, where the PlayStation 2 version was ported and published by Capcom on May 27, 2004, Famitsu gave it a score of one six, two fives, and one six for a total of 22 out of 40. GameSpot named it the best Game Boy Advance game of August 2002.

References

External links

2002 video games
BMX mass media
BMX video games
Hoffman
Hoffman
Cycling video games
Game Boy Advance games
GameCube games
Multiplayer and single-player video games
PlayStation 2 games
Rainbow Studios games
Video game sequels
Video games based on real people
Video games developed in the United Kingdom
Video games developed in the United States
Video games set in the Las Vegas Valley
Xbox games
HotGen games
Gratuitous Games games

Mat Hoffman's Pro BMX 2


Urbain Johnson (January 27, 1824 – April 13, 1917) was a farmer and political figure in the Canadian province of New Brunswick. He represented Kent County in the Legislative Assembly of New Brunswick from 1869 to 1870, from 1874 to 1882 and from 1895 to 1908 as a Liberal member.

He was born and educated at Saint-Louis-de-Kent, New Brunswick, the son of Simon Johnson and Geneviève Vautour. Johnson was a descendant of Scottish immigrants who had first settled among the Acadians in the Chaleur Bay area. In 1856, he married Nathalie Leblanc.

Johnson was first elected to the Legislative Assembly in an 1869 by-election held after Owen McInerney was named to the Legislative Council. Johnson was defeated in the general election which followed in 1870. He opposed the Common Schools Act which banned religious instruction in the province's school system based on the principle of Separation of church and state. He attended the convention of the Société Saint-Jean-Baptiste convention in Quebec City in 1880 and the Acadian national convention in 1881, where he suggested that the Acadians choose a different holiday and symbols from those chosen by other French Canadians. He also was a justice of the peace and an officer in the local militia. Johnson retired from politics in 1908. He died in 1917, aged 93.

References

The Canadian parliamentary companion for 1875, HJ Morgan
Urbain Johnson, McCord Museum of Canadian History
Biographies des élites de la renaissance acadienne (French)

1824 births
1917 deaths
Canadian farmers
New Brunswick Liberal Association MLAs
Acadian people
People from Kent County, New Brunswick
Canadian people of Scottish descent

Urbain Johnson


Barnegat Bay is a small brackish arm of the Atlantic Ocean, approximately  long, along the coast of Ocean County, New Jersey in the United States. It is separated from the Atlantic by the long Island Beach State Park (colloquially called a "barrier island"), as well as by the north end of Long Beach Island, popular segments of the Jersey Shore. The bay is fed by several small rivers, including the Toms River, the Forked River, the Metedeconk River, Cedar Creek, Oyster Creek, Mill Creek, Westecunk Creek, and Tuckerton Creek, all of which empty into the bay through small estuaries along its inner shore. The communities of Toms River, Silverton, and Forked River sit along the river estuaries on the bay.

The bay connects with the ocean through the Barnegat Inlet, along which sits the  Barnegat Lighthouse.  The bay is part of the Atlantic Intracoastal Waterway, entered on its north end by the Point Pleasant Canal and connecting on the south end with Little Egg Harbor via the small Manahawkin Bay. In a broader sense, Barnegat Bay is sometimes considered to stretch to the south end of Long Beach Island and to include Little Egg Harbor.

Three bridges span the bay from the mainland to the peninsula: the Mantoloking Bridge from Brick Township to Mantoloking, and the Thomas A. Mathis and J. Stanley Tunney Bridges from Toms River to Ortley Beach. The Barnegat Division of Edwin B. Forsythe National Wildlife Refuge comprises wetlands along the inner southern part of the bay.  Along the outside of the bay, on the peninsula, is the Island Beach State Park.  Various islands within the bay are a part of the National Wildlife Refuge or the Sedge Islands State Wildlife Management Area.  The northern tip of Long Beach Island includes the Barnegat Lighthouse State Park.

History
The area surrounding Barnegat Bay and Barnegat Inlet was described by Henry Hudson, in 1609, as "... a great lake of water, as we could judge it to be ... The mouth of the lake hath many shoals, and the sea breaketh on them as it is cast out of the mouth of it."  The bay was originally named in 1614 "Barendegat," or "Inlet of the Breakers," by Dutch explorers of the coastline, referring to the waterway's turbulent channel. During the American Revolutionary War, the bay was used as refuge by American privateers.

The bay has been a longtime center for commercial fishing. The village of Toms River was a significant whaling port in the 19th century.  While still popular for fishing, Barnegat Bay has also become a popular destination for recreational boating.  The water quality of the bay has been degraded by pollution in the rivers and creeks that feed it. The preservation of the bay's water quality has been an ongoing effort of several public and private organizations.

The bay was immortalized by the famous writer E. B. White, who used it as a setting for his short story "The Family That Dwelt Apart", published in 1937 as the third story in his long running Preposterous Parables series in The New Yorker. It was adapted into the animated short The Family That Dwelt Apart, narrated by White, by the National Film Board of Canada.

The song "My Eyes Adored You", by New Jersey native Frankie Valli, contains a reference to "walking home every day over Barnegat Bridge and Bay". On March 22, 1975, the song became a Billboard No. 1 hit.

The Trust for Public Land, a national land conservation group, has done extensive work in the Barnegat Bay area for over two decades, protecting over  of land. The Trust recently began the new River to Bay Greenway, the primary goal of which is to create a  multi-use recreational route across southern New Jersey from the Delaware River to Barnegat Bay.

Issues
In the 2000s and 2010s, scientists and residents have drawn attention to fish kills, algal blooms, low dissolved oxygen levels, loss of habitat, diminishing clam populations, and the rise in stinging Chrysaora quinquecirrha (sea nettle jellyfish) populations in the bay, mainly due to high levels of nitrogen from fertilizer runoff. The U.S. Environmental Protection Agency monitors the health of the bay by testing at four locations as frequently as once a week in the summer months, when surface water can reach .

Community members have also expressed concern over the impact of stored radioactive material and thermal pollution at the Oyster Creek Nuclear Generating Station in Lacey Township.  The plant which was built in 1969 was formerly the oldest operating nuclear power plant in the United States. The plant was decommissioned on September 25, 2018.

Pollution
A 2008 baseline sediment pollution study of 15 locations within Barnegat Bay - Little Egg Harbor area including sites at Mill Creek, Cedar Run, Parker Run measured total petroleum hydrocarbons, mercury, polyaromatic hydrocarbons (PAH) and polychlorinated biphenyls (PCB). The joint US/UK team of scientists reported that TPH content was low and that mercury content ranged from <0.02 to 2.61 mg/kg dry wt. PAH content ranged from as low as 37 ug/kg to 1696 ug/kg with the highest concentrations at Tuckerton Creek, nevertheless these concentrations are not considered harmful to humans or biota. The distribution pattern of PAHs throughout the study area was consistent with the burning from grass, wood and coal sources. Concentrations of PCB were below reported effects ranges suggesting a low risk.

Islands
Middle Sedge Island in Barnegat Bay is a  island,  of which are developed with a single house. Other islands include: Little Sedge Island, Northwest Point Island and Marsh Elder Island. Some are privately owned and some are owned by the state of New Jersey.

Pop culture references
Frankie Valli's song "My Eyes Adored You" references the location in the lyrics saying "... over Barnegat Bridge and Bay...".

In the television show The Sopranos, Tony Soprano owns a boat frequently set and docked along Barnegat Bay.

References

External links

State of New Jersey: Barnegat Bay Estuary Program
Save Barnegat Bay – environmental advocacy site
Rutgers University: Barnegat Bay Resources
Jersey City Anglers Association: Future of Barnegat Bay
ReClam the Bay – environmental organization that grows and plants millions of clams and oysters to reclaim Barnegat Bay
Nitrogen Pollution Action Project – guide to eutrophication of Barnegat Bay and solutions

Estuaries of New Jersey
Bays of New Jersey
Bodies of water of Ocean County, New Jersey
Intracoastal Waterway
Long Beach Island

Barnegat Bay


Liquidity regulations are financial regulations designed to ensure that financial institutions (e.g. banks) have the necessary assets on hand in order to prevent liquidity disruptions due to changing market conditions.  This is often related to reserve requirement and capital requirement but focuses on the specific liquidity risk of assets that are held.

These regulations were imposed to negate liquidity risks of banks that played a prominent role in financial crises. Financial banks profit from providing liquidity and maturity transformation, which is the practice by financial institutions of borrowing money on shorter timeframes than they lend money out. In other words, using shorter-term deposits to fund longer-term loans. This can lead to bank runs during which depositors demand repayment of their demandable and maturing deposits, before the borrowers are required to repay the loans. The result could be a liquidity crisis, which refers to an acute shortage (or "drying up") of liquidity.

History
In response to liquidity risks, bank regulators agreed global standards to reduce banks' ability to engage in liquidity and maturity transformation, thereby reducing banks' exposure to runs. Traditionally, the response to this risk was a combination of deposit insurance and discount window access. The former assures depositors not to worry about insolvency, which presumably keeps depositors who thought they might lose their funds entirely, out of the withdrawal line. The latter assures banks have access to short-term liquidity in order to meet the demands of depositors who have an immediate need for cash. These previous regulations were mainly to guard against moral hazard that both programs could create. Over the decades, after the implementation of these regulations, relatively few liquidity problems occurred in the deposit-funded commercial banking system.

2008 financial crisis
Over time there was a vast increase in the creation of so-called cash equivalent instruments, which were supposedly safe, short-term, and liquid, but eventually resulted in poorly underwritten subprime mortgages - a classic adverse feedback loop ensued. This led to the fall of the housing market and the financial crisis of 2008. In response to this failure of liquidity regulations, there has been recent progress in developing new measures to further reinforce the core role of liquidity regulation.

In 2010, the UK Financial Services Authority (FSA) introduced a new liquidity regulation known as the Individual Liquidity Guidance (ILG). In 2013, the Basel Committee on Banking Supervision agreed on a Liquidity Coverage Ratio (LCR), which is similar in design to the ILG but plays a role in an international playing field. The purpose of ILG is to make the banking system more resilient to liquidity shocks by requiring banks to hold a minimum quantity of high quality liquid assets (HQLA). These HQLA consist of cash, central bank reserves and government bonds to cover net outflows of liabilities under two specific stress scenarios, lasting 14 days and 3 months respectively. This way it is assumed that banks that are more heavily dependent on short-term wholesale funding, especially from foreign counterparts, would experience greater funding outflows and therefore need to hold a higher ratio of HQLA to total assets, to ensure immediate survival in stressed funding conditions. The U.S. banking agencies have worked with other regulators in the Basel Committee on Banking Supervision to develop the Net Stable Funding Ratio (NSFR), which is the available amount of stable funding, relative to the required amount of stable funding. It is assumed that this ratio should be at least 100% on an on-going basis. The ratio can be calculated with the following formula:

 ≥ 100%

In this case, the 'available stable funding' is defined as the portion of capital and liabilities expected to be reliable over the time horizon considered by the NSFR, which extends to one year. The amount of such 'stable funding required' of a specific institution is a function of the liquidity characteristics and residual maturities of the various assets held by that institution, and those of its off-balance sheet exposures. In short, the NSFR will require banks to maintain a stable funding profile in relation to the composition of their assets and off-balance sheet activities. Together, the LCR and NSFR are designed to mitigate the risks associated with banks' reliance on unstable funding structures and to encourage them to embrace more resilient funding models. The difference between the two is that the LCR is specifically designed to improve the short-term resilience of banks against liquidity shocks and the NSFR, on the other hand, is designed to limit the risks emanating from excessive maturity mismatches over the medium to long term

Debate
There is some debate on the impact of the LCR and NSFR, since they can at most constrain maturity mismatches within the banking system. The underlying economic core reasons why money suppliers want liquid funds and borrowers want longer-term loans are not changed by these regulations. It is therefore a matter of time until alternative methods of liquidity and maturity transformation will be developed that may result in the next financial crisis. Whether the outcome of these liquidity regulations is a net positive for financial stability is debatable. For further reading on the debatable effects of these liquidity regulations see;

See also
 Basel Accords
 Bank regulation
 Stress test (financial)

References

Financial regulation

Liquidity regulation


The Miller Peninsula is a small peninsula in Clallam County, Washington and Jefferson County, Washington surrounded by Discovery Bay on the east, the Strait of Juan de Fuca to the north, and Sequim Bay to the west.  Small residential communities on the peninsula include Blyn, at the southwest corner; Diamond Point, on the northeast corner; Gardiner, midway down the eastern shore; and Discovery Bay at the foot. See Discovery Bay, Washington for additional detail on placenames in the area.

Peninsulas of Washington (state)
Landforms of Clallam County, Washington
Landforms of Jefferson County, Washington

Miller Peninsula


Zootaxa is a scientific journal that publishes papers of zoology. It is edited by Magnolia Press (Auckland, New Zealand). The magazine was created by Zhi-Qiang Zhang in 2001 and the magazine is issued every week.

Zootaxa is indexed by BIOSIS, Zoological Record and the Current Contents Agriculture, Biology and Environmental Sciences.

References

Other websites

 BioStor: Zootaxa.

Science and technology magazines

Zootaxa


Citizens for Foreign Aid Reform (C-FAR) is one of a number of groups run by neo-Nazi and white supremacist Paul Fromm. It was founded in 1976 by Fromm after he had left the white supremacist Western Guard organization. C-FAR became closely linked to Canadian Association for Free Expression (CAFE), another one of Fromm's groups, which he founded in 1981.  The main issue on C-FAR's agenda has been the promotion of an ultra-right wing agenda that is opposed to foreign aid and immigration.

In 1987, the Toronto Star newspaper described C-FAR as part of a "spider web" of ultra-right wing activists. Apart from foreign aid and immigration, C-FAR's publications also support white supremacy, gun rights, and environmentalism.

It appears that the activities of C-FAR have decreased after Fromm was fired from his position with the Peel Board of Education as a result of his involvement in racist activities.

References
Stanley Barrett: Is God a Racist? The Right Wing in Canada. (Toronto: University of Toronto Press, 1987)
Olivia Ward: "Rightist radicals weave 'spider web' in Canada, Toronto Star, Mar 29, 1987
Paul Fromm: "Group wants cuts in foreign aid spending", Toronto Star, Apr 23, 1987
"Fromm ruling raises bar for teachers", Toronto Star, Apr 09, 2002.

External links
Monday Magazine (Victoria, B.C.):How Hate Spreads A five-part series on C-FAR from 1993.
Nazis In Suits: Paul Fromm & The Far Right
The New Generation of Organised Racialism in Canada
Citizens for Foreign Aid Reform – Canadian Political Parties and Political Interest Groups – Web Archive created by the University of Toronto Libraries

Canadian far-right political movements
Neo-Nazism in Canada
Neo-Nazi organizations

Citizens for Foreign Aid Reform


Franciszek Kostrzewski (19 April 1826, Warsaw – 30 September 1911, Warsaw) was a Polish illustrator, cartoonist, caricaturist, comics artist  and painter in the Realistic style.

Biography
His father was the steward of a city estate. In 1831, following the November Uprising, his family moved to a rural estate in the Sandomierz Voivodeship. He later returned to Warsaw to pursue his studies.

By the time he reached the gymnasium level, he had grown tired of the curriculum and decided to become an artist. His father had other plans, however, and found him a position as a midshipman. Not long after, he was fired when his supervisor found him making sketches on important documents. Following that incident, his father finally relented and, in 1844, he enrolled at the new .

His teachers there included Jan Feliks Piwarski, Chrystian Breslauer and Aleksander Kokular. During his studies, he travelled around the country, painting landscapes, cityscapes and genre scenes; including time spent in Kielce at the invitation of the prominent art collector Tomasz Zieliński (1802–1858). From 1852 to 1853, he worked under the direction of Henryk Pillati, painting decorations for steamships.

After a trip to Germany and Paris in 1856, he settled in Warsaw and contributed drawings to several publications, including Tygodnik Illustrowany,  (Ears) and  (The Wanderer). He was also one of many who illustrated the works of Adam Mickiewicz, as well as the lesser-known works of Władysław Syrokomla and Teofil Lenartowicz.

Over time, his illustrations came to be less critical or satirical and represent a realistic chronicle of life in the capital. He exhibited frequently at the Kraków Society of Friends of Fine Arts and its counterpart in Warsaw, as well as at several commercial salons. He published his memoirs in 1891.

Selected works

See also
 Maria Zandbang

References

Further reading
 Irena Jakimowicz: Franciszek Kostrzewski, Wiedza Powszechna. Państwowe Wydawnictwo Popularno Naukowe, Warsaw, 1952.
 Janusz Durko (ed.) with Irena Tessaro-Kosimowa, Maria Suchodolska and Janina Obidzińska: Franciszek Kostrzewski: katalog prac, Museum of Warsaw, 1963

External links

 Arcadja Auctions: More works by Kostrzewski.

1826 births
1911 deaths
Burials at Powązki Cemetery
19th-century Polish painters
19th-century Polish male artists
20th-century Polish painters
20th-century Polish male artists
Artists from Warsaw
Polish illustrators
Polish cartoonists
Polish caricaturists
Polish comics artists
Polish landscape painters
Polish male painters

Franciszek Kostrzewski


The Dharmamangal () is an important subgenre of mangalkavya, with narratives of local deities of rural Bengal, the most significant genre of medieval Bengali literature. The texts belonging to this subgenre eulogize Dharmathakur, a folk deity worshipped in the Rarh region of Bengal. According to tradition, the earliest poet of Dharmamangal was Mayura Bhatta. The Dharmamangal texts were meant for singing during the twelve-day ritual ceremony, known as Gajan. These texts are part of a larger group of texts associated with the worship of Dharma. In addition to the Dharmamangal texts, this larger group includes a number of works known as the Dharmapurans, which narrate the story of creation and the liturgical works known as the Samjatpaddhatis.

Dharmamangal
The texts of the Dharmamangal comprise two narratives,
 the narrative of the Puranic king Harishchandra, his queen Madana and son Luichandra.  With the grace of god Dharmathakur, Harishchandra was blessed with a son Luichandra, with the condition that the son would be given away to the cult of Dharmathakur. Harishchandra forgot about the condition. Later Dharmathakur showed up as a Brahmin, and asked for the cooked flesh of Luichandra. Harishchandra and Madana killed Luichandra and served his flesh. Luichandra was later restored to life after the king and the queen accepted the Dharmathakur cult.
 the narrative of exploits of a folk hero of Bengal, Lausen.
Most significant poets of Dharmamangal were Rupram Chakrabarty (17th century) and Ghanaram Chakrabarty (17th-18th century). Other poets of Dharmamangal include Khelaram Chakrabarty, Shrishyam Pandit, Dharmadas, Ramdas Adak, Sitaram Das, Yadunath or Yadavram Pandit, Maniklal Ganguli, Ramchandra Bandyopadhyaya, Narasimha Basu, Prabhuram Mukhopadhyaya, Hridayram Sau, Shankar Chakrabarty, Ramnarayan and Ramkanta Ray.

Dharmapuran
The texts of Dharmapuran begin with narrative of creation. The other narratives included in these texts are the narrative about Shiva, the hagiographies of Minanatha and Gorakshanatha, the narrative of Ganga, the narrative of Sada Dom and Ramai Pandit, the description of the atrocities of Dharma in Jajpur and the narrative of king Harishcahndra. The significant poets of Dhramapuran or Anilpuran were Ramai Pandit and Sahadeb Chakrabarty.

Liturgical works
The most significant liturgical work is the Dharmapujavidhan, ascribed to Ramai Pandit as well as to Raghunandan. Another liturgical text, the Yatrasiddharayer Paddhati is a recent work.

See also
 Mangalkavya

References

Bengali-language literature

Dharmamangal


Ongata Rongai (also known as Ronga in local slang) is a town located in Kajiado North, Kajiado County, Kenya. The town is situated  south of the Nairobi CBD and East of the Ngong hills and within the greater Nairobi Metropolitan Region. It lies 1,731 meters (5,682 feet) above sea level. According to the 2019 Census, it is the most populous town in Kajiado County and eleventh largest urban centre by population in Kenya.

Known locally as Rongai or simply Ronga, the populated town is a fast-growing community with an approximate population of 172,590

History
Historically occupied by the Maasai community, the name Ongata Rongai is a Maasai phrase which translates to "narrow plains".

Present-day Ongata Rongai grew from a meeting of a cattle market in the northernmost tip of Kajiado county and the quarry township in present-day Kware. The cattle market and the quarry spread rapidly and joined in the late 1950s.

Due to rapid real estate development starting in the 1990s, Ongata Rongai has evolved into a high-population Nairobi suburb covering around 16 square kilometres. Greater Ongata Rongai is a medium-to-low population area. The neighborhoods of Kandisi, Rimpa, Nkoroi, Merisho, Olekasasi, Tuala, Rangau and Maasai Lodge are located to the south and east of Ongata Rongai.

Ongata Rongai has a diverse population due to its proximity to Nairobi. Ethnic communities represented include Kalenjin, Maasai, Kikuyu, Kamba, Luhya, Luo and Kisii.

One of Rongai's oldest founders is Olekyalosingi

Education
This area is home to a number of institutions of higher learning, such as the Africa Nazarene University, Eagle Air Aviation College, Belmont International College (located at the junction of Magadi/Gataka road in Ongata Rongai Town), Adventist University of Africa, Nairobi Institute of Business Studies (NIBS College) and the nearby Multimedia University of Kenya in Mbagathi. Other learning institutions are Ongata Academy, Laiser Hill Academy, Azuri School Ltd Nkaimurunya Secondary School, Prime Junior School, Nakeel Primary, Nakeel Boys, Arap Moi Primary, Olekasasi Mixed School, and Maxwell Adventist Academy, which together with the Adventist University sit on the property of the headquarters of the Seventh-day Adventist Church for the East-Central African Division. There are also St. Mary's Primary School, Olerai School, P.C.E.A Educational Centre and the latest school in the region, The Champions Academy located at House of Grace Church Ongata Rongai; 300 meters from Laiser Hill School.

The town is home to Multimedia University of Kenya (MMU)  which is the only university in East Africa with an ICT museum.

Cuisine
Ongata Rongai serves as a primary entry point where most fresh produce is transported directly to the towns from the farms. It has a major market for fresh produce around the area of Kware known as Soko Mjinga. The large number of butcheries across Ongata Rongai also bear testimony to the popularity of meat and precisely nyama choma. Sellers of fresh fish are also making their presence felt, citing its immense benefits to the health of consumers.

Urban Culture

Rongai is popular for its pimped matatu's. Matatu's are the main mode of public transport in most urban areas in Kenya. Matatus in Nairobi are identified by a route number, the route number for Rongai is 125 and they operate from a terminus in Nairobi CBD along Moi Avenue next to Haille Selassie roundabout. Rongai matatus are very colorful and are decorated with graffiti representing the latest or popular pop culture: artists, brands or anything trending. Interior is decorated with flashy lights, multiple TV screens and speakers that entertain the commuters with very loud music, there is also free WIFI onboard and mobile charging ports.

Foreigners and tourists usually refer to them as moving discos or night clubs on wheels. Matatus are a part of Nairobi's urban culture, you can not visit the city of Nairobi and fail to ride in a Rongai matatu for an experience of a lifetime.

Some popular matatus that have operated in Rongai are: Catalyst (which won the Best Matatu of the year at Nganya Awards 2016), Boombox, Bond 007, Shakur, Bumblebee, Batman and Superman, Emperor, Amaru, Phantom e.t.c Rongai also won the best route at the Nganya Awards event.

Climatic Condition
Summers are usually overcast and winters are generally cloudy; summers are rarely warm. Winters are brief and cool.

Temperature
With a positive trend indicating warmer weather and a negative trend indicating colder weather, Ongata Rongai's temperature trend reflects the ongoing climate change.

Sports

The town has several sports grounds like Nakeel Stadium which is an arena for Men and  women's football. The stadium is still under renovation.

There is amateur boxing, taekwondo, judo and kungfu at the social hall. However, there is a shortage of equipment for these combat sports. Fitness facilities are available as are several fields for jogging and other outdoor fitness.

See also
 Githurai
 Kahawa
 Kasarani
 Dandora
 Kiserian
 Kitengela
 Ruiru

References

Populated places in Kajiado County

Ongata Rongai