Growth Codes: Intermediate Performance Analysis and Application to Video

Growth codes are a subclass of Rateless codes that have found interesting applications in data dissemination problems. Compared to other Rateless and conventional channel codes, Growth codes show improved intermediate performance which is particularly useful in applications where partial data presents some utility. In this paper, we investigate the asymptotic performance of Growth codes using the Wormald method, which was proposed for studying the Peeling Decoder of LDPC and LDGM codes. Compared to previous works, the Wormald differential equations are set on nodes' perspective which enables a numerical solution to the computation of the expected asymptotic decoding performance of Growth codes. Our framework is appropriate for any class of Rateless codes that does not include a precoding step. We further study the performance of Growth codes with moderate and large size codeblocks through simulations and we use the generalized logistic function to model the decoding probability. We then exploit the decoding probability model in an illustrative application of Growth codes to error resilient video transmission. The video transmission problem is cast as a joint source and channel rate allocation problem that is shown to be convex with respect to the channel rate. This illustrative application permits to highlight the main advantage of Growth codes, namely improved performance in the intermediate loss region.

Impact of Baseline Renal Function on Tenofovir-containing Antiretroviral Therapy Outcomes in Zambia

Background. Although tenofovir (TDF) use has increased as part of first-line antiretroviral therapy (ART) across sub-Saharan Africa, renal outcomes among patients receiving TDF remain poorly understood. We assessed changes in renal function and mortality in patients starting TDF- or non-TDF-containing ART in Lusaka, Zambia. Methods. We included patients aged ≥16 years who started ART from 2007 onward, with documented baseline weight and serum creatinine. Renal dysfunction was categorized as mild (eGFR 60-89 mL/min), moderate (30-59 mL/min) or severe (<30 mL/min) using the CKD-EPI formula. Differences in eGFR during ART were analyzed using linear mixed-effect models, the odds of developing moderate or severe eGFR decrease with logistic regression and mortality with competing risk regression. Results. We included 62,230 adults, of which 38,716 (62%) initiated a TDF-based regimen. The proportion with moderate or severe renal dysfunction at baseline was lower in the TDF compared to the non-TDF group (1.9% vs. 4.0%). Among patients with no or mild renal dysfunction, those on TDF were more likely to develop moderate (adjusted OR: 3.11; 95%CI: 2.52-3.87) or severe eGFR decrease (adjusted OR: 2.43; 95%CI: 1.80-3.28), although the incidence of such episodes was low. Among patients with moderate or severe renal dysfunction at baseline, renal function improved independently of ART regimen and mortality was similar in both treatment groups. Conclusions. TDF use did not attenuate renal function recovery or increase mortality in patients with renal dysfunction. Further studies are needed to determine the role of routine renal function monitoring before and during ART use in Africa.