Genetic recombination is directed away from functional genomic elements in mice

Genetic recombination occurs during meiosis, the key developmental programme of gametogenesis. Recombination in mammals has been recently linked to the activity of a histone H3 methyltransferase, PR domain containing 9 (PRDM9), the product of the only known speciation-associated gene in mammals. PRDM9 is thought to determine the preferred recombination sites--recombination hotspots--through sequence-specific binding of its highly polymorphic multi-Zn-finger domain. Nevertheless, Prdm9 knockout mice are proficient at initiating recombination. Here we map and analyse the genome-wide distribution of recombination initiation sites in Prdm9 knockout mice and in two mouse strains with different Prdm9 alleles and their F(1) hybrid. We show that PRDM9 determines the positions of practically all hotspots in the mouse genome, with the exception of the pseudo-autosomal region (PAR)--the only area of the genome that undergoes recombination in 100% of cells. Surprisingly, hotspots are still observed in Prdm9 knockout mice, and as in wild type, these hotspots are found at H3 lysine 4 (H3K4) trimethylation marks. However, in the absence of PRDM9, most recombination is initiated at promoters and at other sites of PRDM9-independent H3K4 trimethylation. Such sites are rarely targeted in wild-type mice, indicating an unexpected role of the PRDM9 protein in sequestering the recombination machinery away from gene-promoter regions and other functional genomic elements.     

Gut hormones and the regulation of energy homeostasis

Food intake, energy expenditure and body adiposity are homeostatically regulated. Central and peripheral signals communicate information about the current state of energy balance to key brain regions, including the hypothalamus and brainstem. Hunger and satiety represent coordinated responses to these signals, which include neural and hormonal messages from the gut. In recent years our understanding of how neural and hormonal brain-gut signalling regulates energy homeostasis has advanced considerably. Gut hormones have various physiological functions that include specifically targeting the brain to regulate appetite. New research suggests that gut hormones can be used to specifically regulate energy homeostasis in humans, and offer a target for anti-obesity drugs.     

Structural asymmetry and the stability of diverse food webs

Untangling the influence of human activities on food-web stability and persistence is complex given the large numbers of species and overwhelming number of interactions within ecosystems. Although biodiversity has been associated with stability, the actual structures and processes that confer stability to diverse food webs remain largely unknown. Here we show that real food webs are structured such that top predators act as couplers of distinct energy channels that differ in both productivity and turnover rate. Our theoretical analysis shows that coupled fast and slow channels convey both local and non-local stability to food webs. Alarmingly, the same human actions that have been implicated in the loss of biodiversity also directly erode the very structures and processes that we show to confer stability on food webs.     

Revision of the Traumatomutilla juvenilis species group (Hymenoptera,Mutillidae)

ABSTRACT

Traumatomutilla duplicata duplicata (Gerstaecker, 1874), T. duplicata feia Casal, 1969, T. bruchi André, 1908, T. cristata (Gerstaecker, 1874), T. aterrima (Gerstaecker, 1874) and T. lorena (Cresson, 1902) are proposed as junior synonyms of Traumatomutilla bivittata (Gerstaecker, 1874). Traumatomutilla immaculiceps André, 1901, T. bivittata rubroguttata André, 1901 and T. estrella (Cresson, 1902) are proposed as junior synonyms of T. juvenilis (Gerstaecker, 1874). Traumatomutilla bispiculata (André, 1907) is proposed as a junior synonym of T. miniata (Gerstaecker, 1874). The previously unknown males of T. guarata Casal, 1969 and T. juvenilis are described and illustrated. All species of the T. juvenilis species group are redescribed and illustrated. A new species, Traumatomutilla juvenindica Bartholomay & Williams sp. nov., is described based on males and females from northern South America. Additionally, identification keys to the species and known colour forms of the T. juvenilis species group are provided.

http://www.zoobank.org/urn:lsid:zoobank.org:pub:3563B9EE-A45B-4939-8436-7A808D4F8996     

Evaluation of Woven Fabrics for Comfort Properties in Children’s Summer Wear

This paper evaluates the comfort properties of eightkinds of woven fabric commonly used for children'ssummer wear in Hong Kong,China.Due to the expan-sion of children's wear market and the quality require-ment for parents,objective and subjective measurementsare the main methods used to evaluate the chosen fabricsfor garment deslgners and consumers as reference. Objective measurement was carried out through ex-periments by means of the Kawabata Evaluation Systemfor Fabrics(KES-F).Experimental tests on fabrics in-clude compression,surface,bending,air permeability,thermal and tensile.Subjective measurement was con-ducted by a market research on consumers' opinions onfabrics for children's summer wear in the form of ques-tionnaire survey.These two ways of measurement onfabrics were analyzed and compared. It was found that Fabric Sample 6 which is com-posed of polyester and cotton fibre has the best perfor-mance in terms of its comfort properties.Besides,Sam-ple 4 composes of rayon and cotton fibre also ha     

(In)consistency of airsea heat flux estimates; ocean heat uptake anomalies and top of atmosphere radiation budgets

This paper introduces the consistency between top of atmosphere （TOA） imbalances and ocean heat uptake, and the inconsistency between ocean heat uptake estimates and flux climatologies, and then gives some recommendations and outlook.     

An analysis of patient register data in the Longitudinal Study - what does it tell us about the quality of the data?

This article uses data for members of the ONS Longitudinal Study (LS) from both Census 2001 enumeration and patient registrations "frozen" on census day 2001 from the National Health Service Central Register (NHSCR) to examine potential sources of difference in area of usual residence.Overall 95.7 per cent of ONS LS members enumerated at census resided in the same area as recorded on the NHSCR data. Where areas differed, or the ONS LS member was not on the NHSCR on census day, subsequent NHSCR records were examined. Records flagged on the NHSCR as ONS LS members in England and Wales on census day but with no census record were also investigated.     

Riser VIV and its numerical simulation

This paper summarizes some of the typical riser vortex-induced vibration (VIV) problems in subsea oil and gas developments,and presents the corresponding computational fluid dynamics (CFD) time domain simulation results to address these problems. First,the CFD time domain simulation approach was applied to analyze the wake field behind a stationary cylinder and a vibrating cylinder. Then a vertical riser VIV response under uniform current was studied. The VIV response time histories revealed some valuable clues that could lead to explanation of the higher harmonics. After that,a vertical riser VIV response under shear current was investigated. A 3 000 ft (1 ft=0.304 8 m) water depth top tensioned riser was sized,and its VIV responses under uniform and shear current were studied. Then this paper continues to discuss one catenary flexible riser VIV response during normal lay. Last,the time domain simulation approach was applied to a partially submerged flexible jumper,to study the jumper VIV behavior,and dynamic motion envelopes. It was demonstrated that the time domain simulation approach is able to disclose details of the flow field,vortex shedding pattern,and riser dynamic behavior,and han-dle different types of risers under different type of currents.