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"Allen, Robert"
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Absolute Poverty
A new basis for an international poverty measurement is proposed based on linear programming for specifying the least cost diet and explicit budgeting for nonfood spending. This approach is superior to the World Bank’s $1-a-day line because it is (i) clearly related to survival and well being; (ii) comparable across time and space since the same nutritional requirements are used everywhere while nonfood spending is tailored to climate; (iii) adjusts consumption patterns to local prices; (iv) presents no index number problems since solutions are always in local prices; and (v) requires only readily available information. The new approach implies much more poverty than the World Bank’s, especially in Asia.
Journal Article
Fast-degrading elastomer enables rapid remodeling of a cell-free synthetic graft into a neoartery
In the past, small-diameter, synthetic vascular prostheses have been made
in vitro
either entirely from cells or by inoculating cells onto scaffolds. Wei Wu and colleagues have taken a cell-free approach where biodegradable elastomeric grafts are rapidly degraded, producing neoarteries that were almost free of foreign materials 90 days after grafting in a rat abdominal aorta. Grafts were rapidly remodeled by the host and produced compliance and burst pressure values similar to those of native aorta.
Host remodeling is important for the success of medical implants, including vascular substitutes. Synthetic and tissue-engineered grafts have yet to show clinical effectiveness in arteries smaller than 5 mm in diameter. We designed cell-free biodegradable elastomeric grafts that degrade rapidly to yield neoarteries nearly free of foreign materials 3 months after interposition grafting in rat abdominal aorta. This design focuses on enabling rapid host remodeling. Three months after implantation, the neoarteries resembled native arteries in the following aspects: regular, strong and synchronous pulsation; a confluent endothelium and contractile smooth muscle layers; expression of elastin, collagen and glycosaminoglycan; and tough and compliant mechanical properties. Therefore, future studies employing large animal models more representative of human vascular regeneration are warranted before clinical translation. This cell-free approach represents a philosophical shift from the prevailing focus on cells in vascular tissue engineering and may have an impact on regenerative medicine in general.
Journal Article
The biogeophysical effects of carbon fertilization of the terrestrial biosphere
The climate impacts of carbon fertilization of the terrestrial biosphere include cooling associated with the biogeochemical effects of enhanced land carbon storage, whereas the non-carbon-cycle biogeophysical effects associated with changes in surface energy and turbulent heat fluxes may warm or cool the climate system. Both of these effects may be dependent on the background climate. Here, I analyze state-of-the-art CMIP6 Earth system models that conducted simulations driven by 1 % yr−1 increases in atmospheric carbon dioxide (CO2) concentration that isolate the carbon fertilization effect (i.e., CO2 radiative effects are not active) relative to a preindustrial background climate. At the time of CO2 quadrupling, the biogeophysical effects yield multimodel global mean near-surface warming of 0.16±0.09 K, with 13 of the 15 models yielding warming. Using a Surface Energy Balance decomposition, most of this warming is associated with decreases in surface latent heat flux associated with reduced canopy transpiration. Decreases in surface albedo and increases in downwelling shortwave and longwave radiation – both of which are modulated by cloud reductions – are also associated with the warming. Overall, however, the biogeophysical warming is about an order of magnitude smaller than the corresponding cooling associated with enhanced land carbon storage at −1.38 K (−1.92 to −0.84 K). Simulations that isolate the carbon fertilization effect relative to a warmer, higher CO2 background climate yield similar overall results. However, some nuances exist including stronger biogeophysical warming of the extratropics and weaker but nonsignificant biogeophysical warming of the tropics.
Journal Article
El Niño-like teleconnection increases California precipitation in response to warming
Future California (CA) precipitation projections, including those from the most recent Climate Model Intercomparison Project (CMIP5), remain uncertain. This uncertainty is related to several factors, including relatively large internal climate variability, model shortcomings, and because CA lies within a transition zone, where mid-latitude regions are expected to become wetter and subtropical regions drier. Here, we use a multitude of models to show CA may receive more precipitation in the future under a business-as-usual scenario. The boreal winter season-when most of the CA precipitation increase occurs-is associated with robust changes in the mean circulation reminiscent of an El Niño teleconnection. Using idealized simulations with two different models, we further show that warming of tropical Pacific sea surface temperatures accounts for these changes. Models that better simulate the observed El Niño-CA precipitation teleconnection yield larger, and more consistent increases in CA precipitation through the twenty-first century.
California lies in the transition zone where mid-latitude regions are expected to become wetter and subtropical regions drier, and precipitation projections for the region remain uncertain. Here the authors use a multitude of models to show consistent increases in California precipitation under a business-as-usual scenario.
Journal Article
Farm to factory : a reinterpretation of the Soviet industrial revolution
To say that history's greatest economic experiment - Soviet communism - was also its greatest economic failure is to say what many consider obvious. Here, in a reinterpretation, Robert Allen argues that the USSR was one of the most successful developing economies of the 20th century.
Book
MicroRNA-140-5p and SMURF1 regulate pulmonary arterial hypertension
Loss of the growth-suppressive effects of bone morphogenetic protein (BMP) signaling has been demonstrated to promote pulmonary arterial endothelial cell dysfunction and induce pulmonary arterial smooth muscle cell (PASMC) proliferation, leading to the development of pulmonary arterial hypertension (PAH). MicroRNAs (miRs) mediate higher order regulation of cellular function through coordinated modulation of mRNA targets; however, miR expression is altered by disease development and drug therapy. Here, we examined treatment-naive patients and experimental models of PAH and identified a reduction in the levels of miR-140-5p. Inhibition of miR-140-5p promoted PASMC proliferation and migration in vitro. In rat models of PAH, nebulized delivery of miR-140-5p mimic prevented the development of PAH and attenuated the progression of established PAH. Network and pathway analysis identified SMAD-specific E3 ubiquitin protein ligase 1 (SMURF1) as a key miR-140-5p target and regulator of BMP signaling. Evaluation of human tissue revealed that SMURF1 is increased in patients with PAH. miR-140-5p mimic or SMURF1 knockdown in PASMCs altered BMP signaling, further supporting these factors as regulators of BMP signaling. Finally, Smurf1 deletion protected mice from PAH, demonstrating a critical role in disease development. Together, these studies identify both miR-140-5p and SMURF1 as key regulators of disease pathology and as potential therapeutic targets for the treatment of PAH.
Journal Article