A-level common core

The kidney is traditionally regarded as an exocrine gland, producing urine to regulate body fluid volumes and composition and to excrete nitrogenous wastes. In addition to these functions, it is now recognized that a number of hormones are produced within the kidney that have local and systemic actions. These hormones and hormonal cascades include the renin-angiotensin and kallikrein-kinin systems, production of calcitriol, erythropoietin and prostaglandins. These hormones act to influence inter alia blood pressure, sodium and water excretion, red blood cell production, calcium homeostasis and the immune system.     

Identification of sources of resistance to common bacterial blight in common bean in Ethiopia

Common bacterial blight (CBB) caused by Xanthomonas axonopodis pv. phaseoli and X. axonopodis pv. phaseoli var. fuscans is one of the major biotic constraints limiting common bean (Phaseolus vulgaris L.) production and productivity in Ethiopia. The objective of this study was to identify new sources of CBB resistance from a diverse panel of genotypes to develop CBB-resistant common bean varieties. One hundred and ten diverse accessions were evaluated for CBB resistance at three hotspot sites (Melkassa, Arsi Negelle and Mieso) for two seasons (2017 and 2018) in Ethiopia. Data on mean disease severity on leaf (SL) and mean disease severity on pod (SP), the area under disease progress curve (AUDPC), number of pods per plant (PP), number of seeds per pod (SPP) and grain yield (GY) were collected. Data were subjected to standard analysis of variance and principal component analysis. The genotype × site interaction (G × E) had significant (p < .05) effect on all assessed traits. This indicated the presence of marked variation among tested genotypes in CBB resistance across the testing sites. Genotypes including SEC21, SEC23, SMC21, VAX6, SEC12, SEC25, SMC22, VAX5, SEC20, SEC22, SEC24, SEC26, SMC16 SMC24, VAX6, SEC25, SEC21, SEC23 and SMC21 exhibited lower values of SL, SP and AUDPC which are useful genetic resources for future CBB resistance breeding programmes. Nasir provided a grain yield of 3.45 ton/ha followed by VAX1 (2.86 ton/ha) and Hawassa Dume (2.83 ton/ha). Further, CBB-resistant and high yielding genotypes had the higher PPP and SPP making them ideal candidates for common bean breeding in Ethiopia or similar agro-ecologies emphasizing CBB resistance and enhanced agronomic traits.     

Biofeedback use of common objects

Many common devices can be used as biofeedback devices. The feedback use of the bathroom scale in rehabilitation medicine(physical therapy) has been explored with stroke patients. These patients used two scales, one under each foot, to relearn their sense of weight distribution. In addition, the scale was used to teach patients to shift their weight distribution from their knees to their hands as they learned to crawl, and from their feet to their buttocks and the chair as they learned to sit down.     

The common patterns of nature

We typically observe large‐scale outcomes that arise from the interactions of many hidden, small‐scale processes. Examples include age of disease onset, rates of amino acid substitutions and composition of ecological communities. The macroscopic patterns in each problem often vary around a characteristic shape that can be generated by neutral processes. A neutral generative model assumes that each microscopic process follows unbiased or random stochastic fluctuations: random connections of network nodes; amino acid substitutions with no effect on fitness; species that arise or disappear from communities randomly. These neutral generative models often match common patterns of nature. In this paper, I present the theoretical background by which we can understand why these neutral generative models are so successful. I show where the classic patterns come from, such as the Poisson pattern, the normal or Gaussian pattern and many others. Each classic pattern was often discovered by a simple neutral generative model. The neutral patterns share a special characteristic: they describe the patterns of nature that follow from simple constraints on information. For example, any aggregation of processes that preserves information only about the mean and variance attracts to the Gaussian pattern; any aggregation that preserves information only about the mean attracts to the exponential pattern; any aggregation that preserves information only about the geometric mean attracts to the power law pattern. I present a simple and consistent informational framework of the common patterns of nature based on the method of maximum entropy. This framework shows that each neutral generative model is a special case that helps to discover a particular set of informational constraints; those informational constraints define a much wider domain of non‐neutral generative processes that attract to the same neutral pattern.     

The common ancestry of life

Background  

It is common belief that all cellular life forms on earth have a common origin. This view is supported by the universality of the genetic code and the universal conservation of multiple genes, particularly those that encode key components of the translation system. A remarkable recent study claims to provide a formal, homology independent test of the Universal Common Ancestry hypothesis by comparing the ability of a common-ancestry model and a multiple-ancestry model to predict sequences of universally conserved proteins.     

Development of candidate gene markers associated to common bacterial blight resistance in common bean

Common bacterial blight (CBB), caused by Xanthomonas axonopodis pv. phaseoli (Xap), is a major yield-limiting factor of common bean (Phaseolus vulgaris L.) production around the world. Two major CBB-resistant quantitative trait loci (QTL), linked to the sequence characterized amplified region markers BC420 and SU91, are located at chromosomes 6 and 8, respectively. Using map-based cloning approach, four bacterial artificial chromosome (BAC) clones from the BC420-QTL locus and one BAC clone containing SU91 were sequenced by Roche 454 technique and subsequently assembled using merged assemblies from three different programs. Based on the quality of the assembly, only the sequences of BAC 32H6 and 4K7 were used for candidate gene marker (CGM) development and candidate gene (CG) selection. For the BC420-QTL locus, 21 novel genes were predicted in silico by FGENESH using Medicago gene model, whereas 16 genes were identified in the SU91-QTL locus. For each putative gene, one or more primer pairs were designed and tested in the contrasting near isogenic lines. Overall, six and nine polymorphic markers were found in the SU91- and BC420-QTL loci, respectively. Afterwards, association mapping was conducted in a breeding population of 395 dry bean lines to discover marker-trait associations. Two CGMs per each locus showed better association with CBB resistance than the BC420 and SU91 markers, which include BC420-CG10B and BC420-CG14 for BC420_QTL locus, and SU91-CG10 and SU91-CG11 for SU91_QTL locus. The strong associations between CBB resistance and the CGs 10 and 14 from BC420_QTL locus and the CGs 10 and 11 from SU91_QTL locus indicate that the genes 10 and 14 from the BC420 locus are potential CGs underlying the BC420_QTL locus, whereas the genes 10 and 11 from the SU91 locus are potential CGs underlying the SU91_QTL locus. The superiority of SU91-CG11 was further validated in a recombinant inbred line population Sanilac?×?OAC 09-3. Thus, co-dominant CGMs, BC420-CG14 and SU91-CG11, are recommended to replace BC420 and SU91 for marker-assisted selection of common bean with resistance to CBB.     

Selecting a common direction

We present results and analysis of models for contact-induced turning responses and alignment in populations of interacting individuals. Such models describe distributions of orientation, and how these evolve under different assumptions about the turning behaviour of individuals. One of these models was first used to describe interactions between mammalian cells called fibroblasts in Edelstein-Keshet and Ermentrout (1990) J. Math. Biol. 29: 33–58 (henceforth abbreviated EKE 1990). Here the original model is generalized to encompass motion in both 2 and 3 dimensions. Two modifications of this model are introduced: in one, the turning is described by a gradual direction shift (rather than abrupt transition). In another variant, the interactions between individuals changes as the density of the population increases to include the effects of crowding. Using linear stability analysis and synergetics analysis of interacting modes we describe the nature and stability properties of the steady state solutions. We investigate how nonhomogeneous pattern evolves close to the bifurcation point. We find that individuals tend to cluster together in one direction of alignment.     

Selecting a common direction

The problem of alignment of cells (or other objects) that interact in an angle-dependent way was described in Mogilner and Edelstein-Keshet (1995). In this sequel we consider in detail a special limiting case of nearly complete alignment. This occurs when the rotational diffusion of individual objects becomes very slow. In this case, the motion of the objects is essentially deterministic, and the individuals or objects tend to gather in clusters at various orientations. (Numerical solutions show that the angular distribution develops sharp peaks at various discrete orientations.) To understand the behaviour of the deterministic models with analytic tools, we represent the distribution as a number of -like peaks. This approximation of a true solution by a set of (infinitely sharp) peaks will be referred to as thepeak ansatz. For weak but nonzero angular diffusion, the peaks are smoothed out. The analysis of this case leads to a singular perturbation problem which we investigate. We briefly discuss other applications of similar techniques.     

DAPI-inducible common fragile sites

DAPI, a compound specific for the AT bases of DNA, causes gaps and breaks in three human chromosome sites, at the 1q41-1q42 interface, 2q31, and 7p22. It also induces undercondensation of a chromosome site at the 13q21-13q22 interface. The first three sites have the characteristics of "common fragile sites" and are present as gaps and breaks on the chromosomes of seven individuals.