44,972 research outputs found
Zero gravity and cardiovascular homeostasis. The relationship between endogenous hyperprolactinemia and plasma aldosterone
Prolactin, thyrotropin and aldosterone were measured by radioimmunoassay and plasma renin activity by the radioimmunoassay of angiotensin I in normal women before and after the intravenous injection of 200 micrograms of thyrotropin releasing hormone. Prolactin increased at 15 minutes following thyrotropin releasing hormone. Plasma renin activity was not different from control levels during the first hour following the administration of thyrotropin releasing hormone, nor did the plasma aldosterone concentration differ significantly from the control levels during this period. However, with upright posture, an increase in aldosterone and in plasma renin activity was noted, demonstrating a normal capacity to secrete aldosterone. Similarly, no change in aldosterone was seen in 9 patients with primary hypothyroidism given thyrotropin releasing hormone, despite the fact that the increase in prolactin was greater than normal. These data demonstrate that acutely or chronically elevated serum prolactin levels do not result in increased plasma aldosterone levels in humans
Predicting community dynamics of antibiotic-sensitive and -resistant species in fluctuating environments (article)
This is the author accepted manuscript. The final version is available from the Royal Society via the DOI in this recordThe dataset associated with this article is available in ORE: https://doi.org/10.24378/exe.2323Microbes occupy almost every niche within and on their human hosts. Whether colonizing the gut, mouth or bloodstream, microorganisms face temporal fluctuations in resources and stressors within their niche but we still know little of how environmental fluctuations mediate certain microbial phenotypes, notably antimicrobial-resistant ones. For instance, do rapid or slow fluctuations in nutrient and antimicrobial concentrations select for, or against, resistance? We tackle this question using an ecological approach by studying the dynamics of a synthetic and pathogenic microbial community containing two species, one sensitive and the other resistant to an antibiotic drug where the community is exposed to different rates of environmental fluctuation. We provide mathematical models, supported by experimental data, to demonstrate that simple community outcomes, such as competitive exclusion, can shift to coexistence and ecosystem bistability as fluctuation rates vary. Theory gives mechanistic insight into how these dynamical regimes are related. Importantly, our approach highlights a fundamental difference between resistance in single-species populations, the context in which it is usually assayed, and that in communities. While fast environmental changes are known to select against resistance in single-species populations, here we show that they can promote the resistant species in mixed-species communities. Our theoretical observations are verified empirically using a two-species Candida community.European Research Council (ERC)Engineering and Physical Sciences Research Council (EPSRC
Prospects for intermediate mass black hole binary searches with advanced gravitational-wave detectors
We estimated the sensitivity of the upcoming advanced, ground-based
gravitational-wave observatories (the upgraded LIGO and Virgo and the KAGRA
interferometers) to coalescing intermediate mass black hole binaries (IMBHB).
We added waveforms modeling the gravitational radiation emitted by IMBHBs to
detectors' simulated data and searched for the injected signals with the
coherent WaveBurst algorithm. The tested binary's parameter space covers
non-spinning IMBHBs with source-frame total masses between 50 and 1050
and mass ratios between and 1. We found that
advanced detectors could be sensitive to these systems up to a range of a few
Gpc. A theoretical model was adopted to estimate the expected observation
rates, yielding up to a few tens of events per year. Thus, our results indicate
that advanced detectors will have a reasonable chance to collect the first
direct evidence for intermediate mass black holes and open a new, intriguing
channel for probing the Universe over cosmological scales.Comment: 9 pages, 4 figures, corrected the name of one author (previously
misspelled
Correlated fragile site expression allows the identification of candidate fragile genes involved in immunity and associated with carcinogenesis
Background: Common fragile sites (cfs) are specific regions in the human genome that are particularly prone to genomic instability under conditions of replicative stress. Several investigations support the view that common fragile sites play a role in carcinogenesis. We discuss a genome-wide approach based on graph theory and Gene Ontology vocabulary for the functional characterization of common fragile sites and for the identification of genes that contribute to tumour cell biology.
Results: Common fragile sites were assembled in a network based on a simple measure of correlation among common fragile site patterns of expression. By applying robust measurements to capture in quantitative terms the non triviality of the network, we identified several topological features clearly indicating departure from the Erdos-Renyi random graph model. The most important outcome was the presence of an unexpected large connected component far below the percolation threshold. Most of the best characterized common fragile sites belonged to this connected component. By filtering this connected component with Gene Ontology, statistically significant shared functional features were detected. Common fragile sites were found to be enriched for genes associated to the immune response and to mechanisms involved in tumour progression such as extracellular space remodeling and angiogenesis. Moreover we showed how the internal organization of the graph in communities and even in very simple subgraphs can be a starting point for the identification of new factors of instability at common fragile sites.
Conclusion: We developed a computational method addressing the fundamental issue of studying the functional content of common fragile sites. Our analysis integrated two different approaches. First, data on common fragile site expression were analyzed in a complex networks framework. Second, outcomes of the network statistical description served as sources for the functional annotation of genes at common fragile sites by means of the Gene Ontology vocabulary. Our results support the hypothesis that fragile sites serve a function; we propose that fragility is linked to a coordinated regulation of fragile genes expression
Bosonization in the two-channel Kondo model
The bosonization of the anisotropic two-channel Kondo model is shown
to yield two equivalent representations of the original problem. In a straight
forward extension of the Emery-Kivelson approach, the interacting resonant
level model previously derived by the Anderson-Yuval technique is obtained. In
addition, however, a ``(,)'' description is also found. The
strong coupling fixed point of the (,) model was originally
postulated to be related to the intermediate coupling fixed point of the
two-channel Kondo model. The equivalence of the , model to the
two-channel Kondo model is formally established. A summary of what one may
learn from a simple study of these different representations is also given.Comment: 5 pages, latex (uses revtex and epsf macros) with 1 postscript figur
Reply: Endocrine therapy in prostate cancer: time for reappraisal of risks, benefits and cost-effectiveness?
Cultural modulation of face and gaze scanning in young children
Previous research has demonstrated that the way human adults look at others’ faces is modulated by their cultural background, but very little is known about how such a culture-specific pattern of face gaze develops. The current study investigated the role of cultural background on the development of face scanning in young children between the ages of 1 and 7 years, and its modulation by the eye gaze direction of the face. British and Japanese participants’ eye movements were recorded while they observed faces moving their eyes towards or away from the participants. British children fixated more on the mouth whereas Japanese children fixated more on the eyes, replicating the results with adult participants. No cultural differences were observed in the differential responses to direct and averted gaze. The results suggest that different patterns of face scanning exist between different cultures from the first years of life, but differential scanning of direct and averted gaze associated with different cultural norms develop later in life
Conductivity and quasinormal modes in holographic theories
We show that in field theories with a holographic dual the retarded Green's
function of a conserved current can be represented as a convergent sum over the
quasinormal modes. We find that the zero-frequency conductivity is related to
the sum over quasinormal modes and their high-frequency asymptotics via a sum
rule. We derive the asymptotics of the quasinormal mode frequencies and their
residues using the phase-integral (WKB) approach and provide analytic insight
into the existing numerical observations concerning the asymptotic behavior of
the spectral densities.Comment: 24 pages, 3 figure
A systematic literature review on IoT-aware business process modeling views, requirements and notations
The Internet of things has been adopted in several sectors both influencing how people work and enhancing organizations' business processes. This resulted in the rise of relevant research topics such as IoT-aware business processes. The modeling of these processes makes it possible to better understand working scenarios and to support the adoption of model-driven development approaches for IoT-aware and process-oriented software systems. Since much research has been performed on this topic, a better awareness of the current status is needed. This paper reports a systematic literature review to develop a map on modeling notations for IoT-aware business processes. The survey mainly adopts an academic point of view, resulting in the detailed analysis of 84 research works from the leading computer science digital libraries. The output of the review is in the form of schemes and reflections. In particular, our research aims to shed light on (1) the relevant modeling views referring to different types of IoT-aware business processes; (2) the IoT requirements supported by the modeling notations; and (3) the modeling notations proposed and/or adopted to model IoT-aware business processes. Finally, our research work highlights possible future research lines needing further investigations
PMH41 REMISSION CRITERIA FOR DEPRESSION WHEN USING SHORT VERSIONS OF THE HAMILTON DEPRESSION RATING SCALE (HDRS)
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