Conserved Class of Queen Pheromones Stops Social Insect Worker Reproduction

Dissertação de mestrado em Gestão, apresentada à Faculdade de Economia da Universidade de Coimbra, sob a orientação de Patrícia Pereira da SilvaEm 2011, a crise política e financeira de Portugal atingiu um nível crítico, levando à queda do governo, assim como ao pedido de ajuda à denominada Troika, constituída pelo (Fundo Monetário Internacional, Banco Central Europeu e Comunidade Europeia). As recomendações da Troika sobre a política energética Portuguesa basearam-se em torno de medidas que potenciem a eficiência energética, ou seja, medidas que permitam poupar e otimizar consumo de energia. No entanto, sobre as energias renováveis, foi pedida especial atenção, em particular, em tecnologias menos desenvolvidas (incluindo o fotovoltaico), nas quais se deverá efetuar uma análise rigorosa em termos de custos e consequências para o preço da energia. Outra das recomendações da Troika passou por uma revisão em baixo do preço pago pela tarifa (Feed-in tariff), com o intuito de que esse valor não produza compensações alegadamente excessivas para os investidores neste setor. Atendendo às novas constrições anteriormente apresentadas, e aos elevados custo de investimento que as Fontes de Energias Renováveis apresentam, nomeadamente, no setor fotovoltaico, a respetiva avaliação económica assume um papel primordial. É, assim, objetivo desta dissertação estimar da forma mais correta a rendibilidade do investimento, sendo, para tal, desenvolvida uma metodologia de análise de projetos de investimento, usando o método discounted cash flow (DCF) – Free Cash Flow to the firm, bem como, compreender e analisar quais os principais fatores que estão inerentes a um projeto de Fontes de Energia Renovável, nomeadamente, na análise do Levelized Cost Of Electricity (LCOE) e paridade com a rede elétrica. Deste modo, pretende-se uma reanálise do ponto de vista económico de projetos com origem em fontes de energia renovável

Herbivorous turtle ants obtain essential nutrients from a conserved nitrogen-recycling gut microbiome.

Nitrogen acquisition is a major challenge for herbivorous animals, and the repeated origins of herbivory across the ants have raised expectations that nutritional symbionts have shaped their diversification. Direct evidence for N provisioning by internally housed symbionts is rare in animals; among the ants, it has been documented for just one lineage. In this study we dissect functional contributions by bacteria from a conserved, multi-partite gut symbiosis in herbivorous Cephalotes ants through in vivo experiments, metagenomics, and in vitro assays. Gut bacteria recycle urea, and likely uric acid, using recycled N to synthesize essential amino acids that are acquired by hosts in substantial quantities. Specialized core symbionts of 17 studied Cephalotes species encode the pathways directing these activities, and several recycle N in vitro. These findings point to a highly efficient N economy, and a nutritional mutualism preserved for millions of years through the derived behaviors and gut anatomy of Cephalotes ants

The composition of the protosolar disk and the formation conditions for comets

Conditions in the protosolar nebula have left their mark in the composition of cometary volatiles, thought to be some of the most pristine material in the solar system. Cometary compositions represent the end point of processing that began in the parent molecular cloud core and continued through the collapse of that core to form the protosun and the solar nebula, and finally during the evolution of the solar nebula itself as the cometary bodies were accreting. Disentangling the effects of the various epochs on the final composition of a comet is complicated. But comets are not the only source of information about the solar nebula. Protostellar disks around young stars similar to the protosun provide a way of investigating the evolution of disks similar to the solar nebula while they are in the process of evolving to form their own solar systems. In this way we can learn about the physical and chemical conditions under which comets formed, and about the types of dynamical processing that shaped the solar system we see today. This paper summarizes some recent contributions to our understanding of both cometary volatiles and the composition, structure and evolution of protostellar disks.Comment: To appear in Space Science Reviews. The final publication is available at Springer via http://dx.doi.org/10.1007/s11214-015-0167-

Author Correction: Herbivorous turtle ants obtain essential nutrients from a conserved nitrogen-recycling gut microbiome.

The originally published version of the Supplementary Information file associated with this Article contained an error in Supplementary Figure 3. Panel b was inadvertently replaced with a duplicate of panel a. The error has now been fixed and the corrected version of the Supplementary Information PDF is available to download from the HTML version of the Article

Do precocial mammals develop at a faster rate? A comparison of rates of skull development in Sigmodon fulviventer and Mus musculus domesticus

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72993/1/j.1420-9101.2003.00568.x.pd

Rare variant in scavenger receptor BI raises HDL cholesterol and increases risk of coronary heart disease.

Scavenger receptor BI (SR-BI) is the major receptor for high-density lipoprotein (HDL) cholesterol (HDL-C). In humans, high amounts of HDL-C in plasma are associated with a lower risk of coronary heart disease (CHD). Mice that have depleted Scarb1 (SR-BI knockout mice) have markedly elevated HDL-C levels but, paradoxically, increased atherosclerosis. The impact of SR-BI on HDL metabolism and CHD risk in humans remains unclear. Through targeted sequencing of coding regions of lipid-modifying genes in 328 individuals with extremely high plasma HDL-C levels, we identified a homozygote for a loss-of-function variant, in which leucine replaces proline 376 (P376L), in SCARB1, the gene encoding SR-BI. The P376L variant impairs posttranslational processing of SR-BI and abrogates selective HDL cholesterol uptake in transfected cells, in hepatocyte-like cells derived from induced pluripotent stem cells from the homozygous subject, and in mice. Large population-based studies revealed that subjects who are heterozygous carriers of the P376L variant have significantly increased levels of plasma HDL-C. P376L carriers have a profound HDL-related phenotype and an increased risk of CHD (odds ratio = 1.79, which is statistically significant)

Multiband GPI imaging of the HR 4796A debris disk

Stars and planetary system