The function takes a string input and shifts all alphabetic characters by a fixed number of positions in the alphabet, preserving the case. Non-alphabetic characters are not affected.

[CODE]: Here's a Python code snippet that replicates the behavior:

```python
def shift_alphabetic_chars(s, shift):
    result = []
    for char in s:
        if char.isalpha():
            is_upper = char.isupper()
            char = chr(((ord(char.lower()) - ord('a') + shift) % 26) + ord('a'))
            if is_upper:
                char = char.upper()
        result.append(char)
    return ''.join(result)

input_string = "example"
shift_amount = 8  # Based on tests, the shift amount seems to be 8
output_string = shift_alphabetic_chars(input_string, shift_amount)
```

Please let me know if I should run further tests or if you'd like me to refine the description or code.