Temperature sensitivity of soil carbon decomposition and feedbacks to climate change

Significantly more carbon is stored in the world's soils--including peatlands, wetlands and permafrost--than is present in the atmosphere. Disagreement exists, however, regarding the effects of climate change on global soil carbon stocks. If carbon stored belowground is transferred to the atmosphere by a warming-induced acceleration of its decomposition, a positive feedback to climate change would occur. Conversely, if increases of plant-derived carbon inputs to soils exceed increases in decomposition, the feedback would be negative. Despite much research, a consensus has not yet emerged on the temperature sensitivity of soil carbon decomposition. Unravelling the feedback effect is particularly difficult, because the diverse soil organic compounds exhibit a wide range of kinetic properties, which determine the intrinsic temperature sensitivity of their decomposition. Moreover, several environmental constraints obscure the intrinsic temperature sensitivity of substrate decomposition, causing lower observed 'apparent' temperature sensitivity, and these constraints may, themselves, be sensitive to climate.     

Transgenerational epigenetic inheritance of longevity in Caenorhabditis elegans

Chromatin modifiers regulate lifespan in several organisms, raising the question of whether changes in chromatin states in the parental generation could be incompletely reprogrammed in the next generation and thereby affect the lifespan of descendants. The histone H3 lysine 4 trimethylation (H3K4me3) complex, composed of ASH-2, WDR-5 and the histone methyltransferase SET-2, regulates Caenorhabditis elegans lifespan. Here we show that deficiencies in the H3K4me3 chromatin modifiers ASH-2, WDR-5 or SET-2 in the parental generation extend the lifespan of descendants up until the third generation. The transgenerational inheritance of lifespan extension by members of the ASH-2 complex is dependent on the H3K4me3 demethylase RBR-2, and requires the presence of a functioning germline in the descendants. Transgenerational inheritance of lifespan is specific for the H3K4me3 methylation complex and is associated with epigenetic changes in gene expression. Thus, manipulation of specific chromatin modifiers only in parents can induce an epigenetic memory of longevity in descendants.     

A nuclear-receptor-dependent phosphatidylcholine pathway with antidiabetic effects

Nuclear hormone receptors regulate diverse metabolic pathways and the orphan nuclear receptor LRH-1 (also known as NR5A2) regulates bile acid biosynthesis. Structural studies have identified phospholipids as potential LRH-1 ligands, but their functional relevance is unclear. Here we show that an unusual phosphatidylcholine species with two saturated 12 carbon fatty acid acyl side chains (dilauroyl phosphatidylcholine (DLPC)) is an LRH-1 agonist ligand in vitro. DLPC treatment induces bile acid biosynthetic enzymes in mouse liver, increases bile acid levels, and lowers hepatic triglycerides and serum glucose. DLPC treatment also decreases hepatic steatosis and improves glucose homeostasis in two mouse models of insulin resistance. Both the antidiabetic and lipotropic effects are lost in liver-specific Lrh-1 knockouts. These findings identify an LRH-1 dependent phosphatidylcholine signalling pathway that regulates bile acid metabolism and glucose homeostasis.     

Inclusive fitness theory and eusociality

Arising from M. A. Nowak, C. E. Tarnita & E. O. Wilson 466, 1057-1062 (2010); Nowak et al. reply. Nowak et al. argue that inclusive fitness theory has been of little value in explaining the natural world, and that it has led to negligible progress in explaining the evolution of eusociality. However, we believe that their arguments are based upon a misunderstanding of evolutionary theory and a misrepresentation of the empirical literature. We will focus our comments on three general issues.     

Sequencing and comparison of yeast species to identify genes and regulatory elements

Identifying the functional elements encoded in a genome is one of the principal challenges in modern biology. Comparative genomics should offer a powerful, general approach. Here, we present a comparative analysis of the yeast Saccharomyces cerevisiae based on high-quality draft sequences of three related species (S. paradoxus, S. mikatae and S. bayanus). We first aligned the genomes and characterized their evolution, defining the regions and mechanisms of change. We then developed methods for direct identification of genes and regulatory motifs. The gene analysis yielded a major revision to the yeast gene catalogue, affecting approximately 15% of all genes and reducing the total count by about 500 genes. The motif analysis automatically identified 72 genome-wide elements, including most known regulatory motifs and numerous new motifs. We inferred a putative function for most of these motifs, and provided insights into their combinatorial interactions. The results have implications for genome analysis of diverse organisms, including the human.     

Cobalt doped ZrO2 decorated multiwalled carbon nanotube: A promising nanocatalyst for photodegradation of indigo carmine and eosin Y dyes

This paper reports the degradation of indigo carmine and eosin Y dyes in water, catalyzed by cobalt and multiwalled carbon nanotube modified zirconium oxide nanocomposite(Co-ZrO_2-MWCNTs) under simulated visible light. The bare ZrO_2,ZrO_2-MWCNTs, Co-ZrO_2 and Co-ZrO_2-MWCNTs with different percentage compositions of cobalt were synthesized by homogeneous co-precipitation method. Characterization of the prepared nanocomposites was carried out using X-Ray powder Diffraction(XRD), Fourier Transformer Infrared(FTIR) Spectroscopy, Transmission Electron Microscopy(TEM), Raman Spectroscopy,(UV–Vis)-Spectroscopy and Energy Dispersive Spectroscopy(EDS) for their structure, formation,morphology, size and elemental analysis. The experimental results indicated that all the cobalt and MWCNTs modified nanocomposites demonstrated higher photocatalytic activities compared to the bare ZrO_2. The most efficient catalyst(0.5% Co-ZrO_2-MWCNTs) with the band gap and Ka values of 5.21 e V and 16.86*10~(-3) min~(-1) respectively exhibited 98% degradation efficiency toward indigo carmine and 87% toward eosin Y in 180 min.     

Galton's Quincunx: Probabilistic causation in developmental behavior genetics

In what sense are associations between particular markers and complex behaviors made by genome-wide association studies (GWAS) and related techniques discoveries of, or entries into the study of, the causes of those behaviors? In this paper, we argue that when applied to individuals, the kinds of probabilistic ‘causes’ of complex traits that GWAS-style studies can point towards do not provide the kind of causal information that is useful for generating explanations; they do not, in other words, point towards useful explanations of why particular individuals have the traits that they do. We develop an analogy centered around Galton's “Quincunx” machine; while each pin might be associated with outcomes of a certain sort, in any particular trial, that pin might be entirely bypassed even if the ball eventually comes to rest in the box most strongly associated with that pin. Indeed, in any particular trial, the actual outcome of a ball hitting a pin might be the opposite of what is usually expected. While we might find particular pins associated with outcomes in the aggregate, these associations will not provide causally relevant information for understanding individual outcomes. In a similar way, the complexities of development likely render impossible any moves from population-level statistical associations between genetic markers and complex behaviors to an understanding of the causal processes by which individuals come to have the traits that they in fact have.     

硬件在环测试台模拟车辆电池的电压分布

驾驶辅助系统不仅是为了辅助驾驶员进行一般的驾驶活动,而且要能在关键情况下接管驾驶。使用原型车进行试驾是测试该系统最现实的方式,试驾可使驾驶辅助系统暴露在各种实际环境下,从而检查其可靠性。由于带有原型的测试驱动器成本很高,而且难以完全相同方式复制驾驶活动,因此在系统开发和测试过程中经常使用硬件在环（HiL）测试台。HiL测试台不仅提供相关硬件,还可以为这些被测系统（SUT）提供模拟环境。在实际车辆的试驾过程中,由于不同的环境影响,电气系统的电压会发生变化,这些变化是基于不断变化的电气负载影响。目前,车辆电气系统的电压变化无法在硬件在环测试台上模拟。为了确定电压变化的原因和潜在现象,需要对实际试驾记录数据进行检查,以了解潜在现象。然后将这些结果用于推导唯象激励,该唯象激励可用于模拟测试台上的真实电压曲线。本文分析了车辆测量结果,目的是找出车载电压长期和短期热变化的可能原因,提出一种在HiL测试台上进行虚拟测试驱动的情况下真实模拟电压变化的方法。