Rickets: An Overview and Future Directions, with Special Reference to Bangladesh: A Summary of the Rickets Convergence Group Meeting, Dhaka, 26–27 January 2006

Rickets has emerged as a public-health problem in Bangladesh during the past two decades, with up to 8% of children clinically affected in some areas. Insufficiency of dietary calcium is thought to be the underlying cause, and treatment with calcium (350–1,000 mg elemental calcium daily) is curative. Despite this apparently simple treatment, little is known about the most appropriate management of bone deformities of affected children, and further studies are needed to determine the details of dosing and duration of calcium therapy, the role of bracing, and specific indications for surgical intervention. Effective preventive measures that can feasibly reach entire communities are needed, and these may differ between various affected regions

Rickets: An Overview and Future Directions, with Special Reference to Bangladesh: A Summary of the Rickets Convergence Group Meeting, Dhaka, 26-27 January 2006

Rickets has emerged as a public-health problem in Bangladesh during the past two decades, with up to 8% of children clinically affected in some areas. Insufficiency of dietary calcium is thought to be the underlying cause, and treatment with calcium (350-1,000 mg elemental calcium daily) is curative. Despite this apparently simple treatment, little is known about the most appropriate management of bone deformities of affected children, and further studies are needed to determine the details of dosing and duration of calcium therapy, the role of bracing, and specific indications for surgical intervention. Effective preventive measures that can feasibly reach entire communities are needed, and these may differ between various affected regions

.f5qA)ozoDo"z32zc INVESTIGATION OF FACTORS INFLUENCING THE ACCURACY OF PYRHELIOMETER CALIBRATIONS

ABSTRACT The accuracy of solar cells calibrated as primary reference cells is directly dependent on the accuracy of the pyrheliometer used to measure the direct beam solar irradtance on the cell. Pyrheliometers are also used in measuring performance of concentrating photovoltaic modules. In order to reduce errors in photovoltaic performance measurements, we have investigated the calibration uncertainties for pyrheliometers from two manufacturers. Our calibration comparisons are relative to an absolute cavity radiometer traceable to the World Radiometric Reference. This paper quantifies the effects of aging, temperature, time-rate-of-change of temperature, wind, solar spectral shifts, linearity, window transmission, and solar tracking on pyrheliometer calibrations. Uncertainty remaining after accounting for these factors is 0.8% at the 2-sigma level