Growth volatility and technical progress: a simple rent-seeking model

Recent empirical evidence demonstrates that a higher level of technical progress is associated with a lower level of growth volatility and higher expected economic growth. This paper builds a simple growth model which combines the insights of Angeletos and Kollintzas (2000) and Tse (2000, 2001, 2002) with endogenous productivity growth and rent-seeking behavior to account for these stylized facts. Our model also complements the literature that focuses on the heterogeneity of different agents. Future research directions are also discussed.volatility of economic growth, technical progress, rent-seeking, stabilization policy, institution.

Towards Equity in Health: Researchers Take Stock.

For the 2016 end-of-the-year editorial, the PLOS Medicine editors asked 7 global health leaders to discuss developments relevant to the equitable provision of medical care to all populations. The result is a collection of expert views on ethical trial design, research during outbreaks, high-burden infectious diseases, diversity in research and protection of migrants

Synthetic Studies in Phytochrome Chemistry

An account is given of the author’s several approaches to the synthesis of the parent chromophore of phytochrome (1), a protein-bound linear tetrapyrrole derivative that controls photomorphogenesis in higher plants. These studies culminated in enantioselective syntheses of both (2R)- and (2S)-phytochromobilin (4), as well as several 13C-labeled derivatives designed to probe the site of Z,E-isomerization during photoexcitation. When reacted in vitro, synthetic 2R-4 and recombinant-derived phytochrome apoprotein N-C produced a protein-bound chromophore with identical difference spectra to naturally occurring 1

Pegylated derivatives of recombinant human arginase (rhArg1) for sustained in vivo activity in cancer therapy: preparation, characterization and analysis of their pharmacodynamics in vivo and in vitro and action upon hepatocellular carcinoma cell (HCC)

<p>Abstract</p> <p>Background</p> <p>Protein used in medicine, e.g. interferon, are immunogenic and quickly broken down by the body. Pegylation is a recognized way of preserving their integrity and reducing immune reactions, and works well with enzymes used to degrade amino acids, a recent focus of attention in controlling cancer growth. Of the two arginine-degrading enzymes being explored clinically, arginine deiminase is a decidedly foreign mycoplasm-derived enzyme, whereas human arginase 1 is a native liver enzyme. Both have been pegylated, the former with adjuncts of 20 kD, the latter with 5 kD PEG. Pegylation is done by several different methods, not all of which are satisfactory or desirable.</p> <p>Methods</p> <p>The preparation of novel polyethylene glycol (PEG) derivatives for modifying proteins is described, but directed specifically at pegylation of recombinant human arginase 1 (rhArg1). rhArg1 expressed in <it>Escherichia coli </it>was purified and coupled in various ways with 5 different PEG molecules to compare their protective properties and the residual enzyme activity, using hepatocellular cell lines both in vitro and in vivo.</p> <p>Results</p> <p>Methoxypolyethylene glycol-succinimidyl propionate (mPEG-SPA 5,000) coupled with very high affinity under mild conditions. The resulting pegylated enzyme (rhArg1-peg_{5,000 mw}) had up to 6 PEG chains of 5K length which not only protected it from degradation and any residual immunogenicity, but most importantly let it retain >90% of its native catalytic activity. It remained efficacious in depleting arginine in rats after a single ip injection of 1,500 U of the conjugate as the native enzyme, plasma arginine falling to >0.05 μM from ~170 μM within 20 min and lasting 6 days. The conjugate had almost the same efficacy as unpegylated rhArg1 on 2 cultured human liver cancer (HCC) cell lines. It was considerably more effective than 4 other pegylated conjugates prepared.</p> <p>Conclusion</p> <p>Valuable data on the optimization of the pegylation procedure and choice of ligand that best stabilizes the enzyme arginase 1 are presented, a protocol that should equally fit many other enzymes and proteins. It is a long lasting arginine-depleting enzyme in vivo which will greatly improve its use in anti-cancer therapy.</p

Evaluation of global fire simulations in CMIP6 Earth system models

Fire is the primary form of terrestrial ecosystem disturbance on a global scale and an important Earth system process. Most Earth system models (ESMs) have incorporated fire modeling, with 19 out of them submitting model outputs of fire-related variables to the Coupled Model Intercomparison Project Phase 6 (CMIP6). This study provides the first comprehensive evaluation of CMIP6 historical fire simulations by comparing them with multiple satellite-based products and charcoal-based historical reconstructions. Our results show that most CMIP6 models simulate the present-day global burned area and fire carbon emissions within the range of satellite-based products. They also capture the major features of observed spatial patterns and seasonal cycles, the relationship of fires with precipitation and population density, and the influence of El Ni&ntilde;o-Southern Oscillation (ENSO) on the interannual variability of tropical fires. Regional fire carbon emissions simulated by the CMIP6 models from 1850 to 2010 generally align with the charcoal-based reconstructions, although there are regional mismatches, such as in southern South America and eastern temperate North America prior to the 1910s and in temperate North America, eastern boreal North America, Europe, and boreal Asia since the 1980s. The CMIP6 simulations have addressed three critical issues identified in the CMIP5: (1) the simulated global burned area less than half of the observations, (2) the failure to reproduce the high burned area fraction observed in Africa, and (3) the weak fire seasonal variability. Furthermore, the CMIP6 models exhibit improved accuracy in capturing the observed relationship between fires and both climatic and socioeconomic drivers, and better align with the historical long-term trends indicated by charcoal-based reconstructions in most regions worldwide. However, the CMIP6 models still fail to reproduce the decline in global burned area and fire carbon emissions observed over the past two decades, mainly attributed to an underestimation of anthropogenic fire suppression, and the spring peak in fires in the Northern Hemisphere mid-latitudes, mainly due to an underestimation of crop fires. In addition, the model underestimates the fire sensitivity to wet-dry conditions, indicating the need to improve fuel wetness estimation. Based on these findings, we present specific guidance for fire scheme development and suggest the post-processing methodology for using CMIP6 multi-model outputs to generate reliable fire projection products

The Risk of Obstructive Lung Disease by Previous Pulmonary Tuberculosis in a Country with Intermediate Burden of Tuberculosis

We evaluated the effects of previous pulmonary tuberculosis (TB) on the risk of obstructive lung disease. We analyzed population-based, the Second Korea National Health and Nutrition Examination Survey 2001. Participants underwent chest X-rays (CXR) and spirometry, and qualified radiologists interpreted the presence of TB lesion independently. A total of 3,687 underwent acceptable spirometry and CXR. Two hundreds and ninty four subjects had evidence of previous TB on CXR with no subjects having evidence of active disease. Evidence of previous TB on CXR were independently associated with airflow obstruction (adjusted odds ratios [OR] = 2.56 [95% CI 1.84-3.56]) after adjustment for sex, age and smoking history. Previous TB was still a risk factor (adjusted OR = 3.13 [95% CI 1.86-5.29]) with exclusion of ever smokers or subjects with advanced lesion on CXR. Among never-smokers, the proportion of subjects with previous TB on CXR increased as obstructive lung disease became more severe. Previous TB is an independent risk factor for obstructive lung disease, even if the lesion is minimal and TB can be an important cause of obstructive lung disease in never-smokers. Effort on prevention and control of TB is crucial in reduction of obstructive lung disease, especially in countries with more than intermediate burden of TB

SNVMix: predicting single nucleotide variants from next-generation sequencing of tumors

Motivation: Next-generation sequencing (NGS) has enabled whole genome and transcriptome single nucleotide variant (SNV) discovery in cancer. NGS produces millions of short sequence reads that, once aligned to a reference genome sequence, can be interpreted for the presence of SNVs. Although tools exist for SNV discovery from NGS data, none are specifically suited to work with data from tumors, where altered ploidy and tumor cellularity impact the statistical expectations of SNV discovery