anchor.diff:    <li><%= link_to t('.about'), about_path %></li>
     <li><%= link_to t('.help'), help_path %></li>
     <li><a href="https://www.coursera.org/course/techcity"><%= t '.technicity' %></a></li>
  -  <!--  
  -  <li><%= link_to t('.public_studies'), studies_path %></li>
  +
  +  <!-- <li><%= link_to t('.public_studies'), studies_path %></li> -->
     <% if user_signed_in? %>
       <li><%= link_to t('.my_research'), studies_path %></li>
       <li class="dropdown">
  
positive.code:     </li>
    <% end %>
  
    
  </ul>
  <%= link_to "Sign up", new_user_registration_path %>
  -->
  
negative.code:   <% else %>
      <li><%= link_to t('.login'), new_user_session_path %></li>
    <% end %>
  </ul>
  
  
  
  <!-- OLD
    <li class="dropdown">
      <a href="/dashboard" class="dropdown-toggle" data-toggle="dropdown">Public Studies
      <b class="caret"></b></a>
      <ul class="dropdown-menu">
        <li><a href="/dashboard">Dashboard</a></li>
  