Fistulas First—But Can They Last?

Fistulas first--but can they last?

Efforts during the past 5 to 10 years to increase the proportion of patients in the United States who receive maintenance hemodialysis via a native arteriovenous (AV) fistula have been successful. In 2008, 55% of prevalent patients in the United State were undergoing dialysis via a fistula compared with only 35% in 2003 (1,2). Despite this substantial progress, challenges remain, among the most...

Bone allografts: What they can offer and what they cannot.

Bone allografts can be used in any kind of surgery involving bone from minor defects to major bone loss after tumour resection. This review describes the various types of bone grafts and the current knowledge on bone allografts, from procurement and preparation to implantation. The surgical conditions for optimising the incorporation of bone are outlined, and surgeon expectations from a bone al...

Revisiting Class-Size Effects: Where They Come From and How Long They Last

Using data from the Tennessee Student/Teacher Achievement Ratio experiment and subsequent follow-up surveys, we estimate unconditional quantile treatment effects of being assigned to a small-size class and a regular-size class with an aide, compared to regular-size one. Results show that mid-achievers profit the most from being assigned to a small class. Students at the bottom or top of the ach...

Awards and Competitions. What They Can Do and How They Can Do It

Heavy sterile neutrinos - what they can be and what they can ’ t

We review current astrophysical bounds on MeV sterile neutrinos, and then we discuss why a sterile keV neutrino is a natural warm dark matter candidate.