I am a bit suprised/confused about the following difference between numpy and Pandas

```
import numpy as np
import pandas as pd
a = np.random.randn(10,10)

> a[:3,0, newaxis]

array([[-1.91687144],
       [-0.6399471 ],
       [-0.10005721]])

```

However:

```
b = pd.DataFrame(a)

> b.ix[:3,0]

0   -1.916871
1   -0.639947
2   -0.100057
3    0.251988

```

In other words, numpy does not include the `stop` index in `start:stop` notation, but Pandas does. I thought Pandas was based on Numpy. Is this a bug? Intentional?