Semiconductor disk lasers: the future's bright; the colour's flexible

Presentation describing semiconductor disk lasers, their use and how they work

Climatic niche shifts between species' native and naturalized ranges raise concern for ecological forecasts during invasions and climate change

Copyright © 2014 WileyAim: Correlative models that forecast extinction risk from climate change and invasion risks following species introductions, depend on the assumption that species’ current distributions reflect their climate tolerances (‘climatic equilibrium’). This assumption has rarely been tested with independent distribution data, and studies that have done so have focused on species that are widespread or weedy in their native range. We use independent data to test climatic equilibrium for a broadly representative group of species, and ask whether there are any general indicators that can be used to identify when equilibrium occurs. Location: Europe and contiguous USA. Methods: We contrasted the climate conditions occupied by 51 plant species in their native (European) and naturalized (USA) distributions by applying kernel smoothers to species’ occurrence densities. We asked whether species had naturalized in climate conditions that differ from their native ranges, suggesting climatic disequilibrium in the native range, and whether characteristics of species’ native distributions correspond with climatic equilibrium. Results: A large proportion of species’ naturalized distributions occurred outside the climatic conditions occupied in their native ranges: for 22 species, the majority of their naturalized ranges fell outside their native climate conditions. Our analyses revealed large areas in Europe that species do not occupy, but which match climatic conditions occupied in the USA, suggesting a high degree of climatic disequilibrium in the native range. Disequilibrium was most severe for species with native ranges that are small and occupy a narrow range of climatic conditions. Main conclusions: Our results demonstrate that the direct effects of climate on species distributions have been widely overestimated, and that previous large-scale validations of the equilibrium assumption using species’ native and naturalized distributions are not generally applicable. Non-climatic range limitations are likely to be the norm, rather than the exception, and pose added risks for species under climate change.Fundação para a Ciência e a Technologi

Large-scale H I in nearby radio galaxies - II. The nature of classical low-power radio sources

An important aspect of solving the long-standing question as to what triggers various types of active galactic nuclei (AGN) involves a thorough understanding of the overall properties and formation history of their host galaxies. This is the second in a series of papers that systematically study the large-scale properties of cold neutral hydrogen (H I) gas in nearby radio galaxies. The main goal is to investigate the importance of gas-rich galaxy mergers and interactions among radio-loud AGN. In this paper, we present results of a complete sample of classical low-power radio galaxies. We find that extended Fanaroff & Riley type-I radio sources are generally not associated with gas-rich galaxy mergers or ongoing violent interactions, but occur in early-type galaxies without large (>rsim 108 M⊙) amounts of extended neutral hydrogen gas. In contrast, enormous discs/rings of H I gas (with sizes up to 190 kpc and masses up to 2 × 1010 M⊙) are detected around the host galaxies of a significant fraction of the compact radio sources in our sample. This segregation in H I mass with radio-source size likely indicates that either these compact radio sources are confined by large amounts of gas in the central region or that their fuelling is inefficient and different from the fuelling process of classical FR I radio sources. To first order, the overall H I properties of our complete sample (detection rate, mass and morphology) appear similar to those of radio-quiet early-type galaxies. If confirmed by better statistics, this would imply that low-power radio-AGN activity may be a short and recurrent phase that occurs at some point during the lifetime of many early-type galaxies

The functional role of biodiversity in ecosystems: incorporating trophic complexity

Understanding how biodiversity affects functioning of ecosystems requires integrating diversity within trophic levels (horizontal diversity) and across trophic levels (vertical diversity, including food chain length and omnivory). We review theoretical and experimental progress toward this goal. Generally, experiments show that biomass and resource use increase similarly with horizontal diversity of either producers or consumers. Among prey, higher diversity often increases resistance to predation, due to increased probability of including inedible species and reduced efficiency of specialist predators confronted with diverse prey. Among predators, changing diversity can cascade to affect plant biomass, but the strength and sign of this effect depend on the degree of omnivory and prey behaviour. Horizontal and vertical diversity also interact: adding a trophic level can qualitatively change diversity effects at adjacent levels. Multitrophic interactions produce a richer variety of diversity‐functioning relationships than the monotonic changes predicted for single trophic levels. This complexity depends on the degree of consumer dietary generalism, trade‐offs between competitive ability and resistance to predation, intraguild predation and openness to migration. Although complementarity and selection effects occur in both animals and plants, few studies have conclusively documented the mechanisms mediating diversity effects. Understanding how biodiversity affects functioning of complex ecosystems will benefit from integrating theory and experiments with simulations and network‐based approaches

An Experimental Investigation of Colonel Blotto Games

"This article examines behavior in the two-player, constant-sum Colonel Blotto game with asymmetric resources in which players maximize the expected number of battlefields won. The experimental results support all major theoretical predictions. In the auction treatment, where winning a battlefield is deterministic, disadvantaged players use a 'guerilla warfare' strategy which stochastically allocates zero resources to a subset of battlefields. Advantaged players employ a 'stochastic complete coverage' strategy, allocating random, but positive, resource levels across the battlefields. In the lottery treatment, where winning a battlefield is probabilistic, both players divide their resources equally across all battlefields." (author's abstract)"Dieser Artikel untersucht das Verhalten von Individuen in einem 'constant-sum Colonel Blotto'-Spiel zwischen zwei Spielern, bei dem die Spieler mit unterschiedlichen Ressourcen ausgestattet sind und die erwartete Anzahl gewonnener Schlachtfelder maximieren. Die experimentellen Ergebnisse bestätigen alle wichtigen theoretischen Vorhersagen. Im Durchgang, in dem wie in einer Auktion der Sieg in einem Schlachtfeld deterministisch ist, wenden die Spieler, die sich im Nachteil befinden, eine 'Guerillataktik' an, und verteilen ihre Ressourcen stochastisch auf eine Teilmenge der Schlachtfelder. Spieler mit einem Vorteil verwenden eine Strategie der 'stochastischen vollständigen Abdeckung', indem sie zufällig eine positive Ressourcenmenge auf allen Schlachtfeldern positionieren. Im Durchgang, in dem sich der Gewinn eines Schlachtfeldes probabilistisch wie in einer Lotterie bestimmt, teilen beide Spieler ihre Ressourcen gleichmäßig auf alle Schlachtfelder auf." (Autorenreferat

Risk factors for surgical site infections using a data-driven approach

Objective The objective of this study was to identify risk factors for surgical site infection from digestive, thoracic and orthopaedic system surgeries using clinical and data-driven cut-off values. A second objective was to compare the identified risk factors in this study to risk factors identified in literature. Summary background data Retrospective data of 3 250 surgical procedures performed in large tertiary care hospital in The Netherlands during January 2013 to June 2014 were used. Methods Potential risk factors were identified using a literature scan and univariate analysis. A multivariate forward-step logistic regression model was used to identify risk factors. Standard medical cut-off values were compared with cut-offs determined from the data. Results For digestive, orthopaedic and thoracic system surgical procedures, the risk factors identified were preoperative temperature of �38˚C and antibiotics used at the time of surgery. Creactive protein and the duration of the surgery were identified as a risk factors for digestive surgical procedures. Being an adult (age �18) was identified as a protective effect for thoracic surgical procedures. Data-driven cut-off values were identified for temperature, age and CRP which can explain the SSI outcome up to 19.5% better than generic cut-off values. Conclusions This study identified risk factors for digestive, orthopaedic and thoracic system surgical procedures and illustrated how data-driven cut-offs can add value in the process. Future studies should investigate if data-driven cut-offs can add value to explain the outcome being modelled and not solely rely on standard medical cut-off values to identify risk factors

The ELT-2 GATA-factor and the global regulation of transcription in the C. elegans intestine

AbstractA SAGE library was prepared from hand-dissected intestines from adult Caenorhabditis elegans, allowing the identification of >4000 intestinally-expressed genes; this gene inventory provides fundamental information for understanding intestine function, structure and development. Intestinally-expressed genes fall into two broad classes: widely-expressed “housekeeping” genes and genes that are either intestine-specific or significantly intestine-enriched. Within this latter class of genes, we identified a subset of highly-expressed highly-validated genes that are expressed either exclusively or primarily in the intestine. Over half of the encoded proteins are candidates for secretion into the intestinal lumen to hydrolyze the bacterial food (e.g. lysozymes, amoebapores, lipases and especially proteases). The promoters of this subset of intestine-specific/intestine-enriched genes were analyzed computationally, using both a word-counting method (RSAT oligo-analysis) and a method based on Gibbs sampling (MotifSampler). Both methods returned the same over-represented site, namely an extended GATA-related sequence of the general form AHTGATAARR, which agrees with experimentally determined cis-acting control sequences found in intestine genes over the past 20 years. All promoters in the subset contain such a site, compared to <5% for control promoters; moreover, our analysis suggests that the majority (perhaps all) of genes expressed exclusively or primarily in the worm intestine are likely to contain such a site in their promoters. There are three zinc-finger GATA-type factors that are candidates to bind this extended GATA site in the differentiating C. elegans intestine: ELT-2, ELT-4 and ELT-7. All evidence points to ELT-2 being the most important of the three. We show that worms in which both the elt-4 and the elt-7 genes have been deleted from the genome are essentially wildtype, demonstrating that ELT-2 provides all essential GATA-factor functions in the intestine. The SAGE analysis also identifies more than a hundred other transcription factors in the adult intestine but few show an RNAi-induced loss-of-function phenotype and none (other than ELT-2) show a phenotype primarily in the intestine. We thus propose a simple model in which the ELT-2 GATA factor directly participates in the transcription of all intestine-specific/intestine-enriched genes, from the early embryo through to the dying adult. Other intestinal transcription factors would thus modulate the action of ELT-2, depending on the worm's nutritional and physiological needs

Adaptive Challenges, Adaptive Work, and Adaptive Leadership Among Women Living With HIV in the Southern United States: Findings From a Qualitative Study

Women living with HIV have a higher burden of non-AIDS comorbidities and prevalence of chronic conditions. The Adaptive Leadership Framework for Chronic Illness clarifies living with complex health challenges by delineating the technical work of health care providers as well as the adaptive work and leadership behaviors of patients and their providers. We conducted a descriptive, qualitative study of women residing in the Southern United States who were participating in the Women's Interagency HIV Study in North Carolina. Twenty-two participants (mean age = 52.2 years; 90.9% self-identifying as Black or African American) completed semi-structured qualitative interviews. We identified adaptive challenges (e.g., affective and disclosure challenges) and adaptive work and leadership behaviors. Women learned skills to care for their health and support their families and to work with their providers to manage their care. Findings support the importance of identifying leadership behaviors for the purpose of developing person-centered interventions