2,098 research outputs found
Avian malaria is absent in juvenile colonial herons (Ardeidae) but not Culex pipiens mosquitoes in the Camargue, Southern France
Apicomplexan blood parasites Plasmodium and Haemoproteus (together termed âAvian malariaâ) and Leucocytozoon are widespread, diverse vector-transmitted blood parasites of birds, and conditions associated with colonial nesting in herons (Ardeidae) and other waterbirds appear perfect for their transmission. Despite studies in other locations reporting high prevalence of parasites in juvenile herons, juvenile Little Egrets (Egretta garzetta) previously tested in the Camargue, Southern France, had a total absence of malaria parasites. This study tested the hypotheses that this absence was due to insufficient sensitivity of the tests of infection; an absence of infective vectors; or testing birds too early in their lives. Blood was sampled from juveniles of four species shortly before fledging: Little Egret (n = 40), Cattle Egret (Bubulcus ibis; n = 40), Black-crowned Night-Heron (Nycticorax nycticorax, n = 40), and Squacco Heron (Ardeola ralloides; n = 40). Sensitive nested-Polymerase Chain Reaction was used to test for the presence of parasites in both birds and host-seeking female mosquitoes captured around the colonies. No malaria infection was found of in any of the heron species. Four different lineages of Plasmodium were detected in pooled samples of female Culex pipiens mosquitoes, including two in potentially infective mosquitoes. These results confirm that the absence of malaria parasites previously demonstrated in Little Egret is not due to methodological limitations. Although the prevalence of infection in mosquitoes was low, conditions within the colonies were suitable for transmission of Plasmodium. These colonial heron species may have evolved strategies for resisting malaria infection through physiological or behavioral mechanisms
Recommendations of the Stiglitz-Sen-Fitoussi Report: A few illustrations
In September 2009 the Stiglitz-Sen-Fitoussi Commission submitted its report on the measurement of economic performance and social progress. The report is based on a large body of applied research work conducted in recent years in various fields of the economic and social sciences. Some of this research work proposes composite well-being indicators more appropriate than GDP. A parallel trend rather favours the construction of dashboards, i.e. sets of indicators designed to provide an understanding of the several facets of economic performance and quality of life. Without neglecting the interest of constructing composite indicators, the commission strongly emphasized the multidimensional nature of well-being. To address this multidimensional nature, it did not propose its own ready-made dashboard. The report must rather be read as providing guidelines to be followed for constructing such a dashboard. This dossier outlines the main lessons to be learned from a comparison between France and a few other countries with the same level of development, as measured against the criteria used by the Stiglitz Commission. The use of alternative standard of living indicators involves a few reclassifications across countries but without really calling into question the apparent advance of the United States. However, living conditions indicators do show far more marked contrasts in the areas of health, education, the risks of unemployment and poverty, and security. Contributions to the problem of climatic sustainability can be up to three times greater from one country to the next. As for economic sustainability, the indicator proposed by the commission suggests that this sustainability remains warranted, although with a fairly small safety margin in several countries.Stiglitz-Sen-Fitoussi report, measurement of well-being, international comparison, quality of life, sustainable development, economic growth
On localized vegetation patterns, fairy circles and localized patches in arid landscapes
We investigate the formation of localized structures with a varying width in
one and two-dimensional systems. The mechanism of stabilization is attributed
to strong nonlocal coupling mediated by a Lorentzian type of Kernel. We show
that, in addition to stable dips found recently [see, e.g., C. Fernandez-Oto,
M. G. Clerc, D. Escaff, and M. Tlidi, Phys. Rev. Lett. {\bf{110}}, 174101
(2013)], exist stable localized peaks which appear as a result of strong
nonlocal coupling, i.e. mediated by a coupling that decays with the distance
slower than an exponential. We applied this mechanism to arid ecosystems by
considering a prototype model of a Nagumo type. In one-dimension, we study the
front that connects the stable uniformly vegetated state with the bare one
under the effect of strong nonlocal coupling. We show that strong nonlocal
coupling stabilizes both---dip and peak---localized structures. We show
analytically and numerically that the width of localized dip, which we
interpret as fairy circle, increases strongly with the aridity parameter. This
prediction is in agreement with filed observations. In addition, we predict
that the width of localized patch decreases with the degree of aridity.
Numerical results are in close agreement with analytical predictions
Plant clonal morphologies and spatial patterns as self-organized responses to resource-limited environments
We propose here to interpret and model peculiar plant morphologies (cushions,
tussocks) observed in the Andean altiplano as localized structures. Such
structures resulting in a patchy, aperiodic aspect of the vegetation cover are
hypothesized to self-organize thanks to the interplay between facilitation and
competition processes occurring at the scale of basic plant components
biologically referred to as 'ramets'. (Ramets are often of clonal origin.) To
verify this interpretation, we applied a simple, fairly generic model (one
integro-differential equation) emphasizing via Gaussian kernels non-local
facilitative and competitive feedbacks of the vegetation biomass density on its
own dynamics. We show that under realistic assumptions and parameter values
relating to ramet scale, the model can reproduce some macroscopic features of
the observed systems of patches and predict values for the inter-patch distance
that match the distances encountered in the reference area (Sajama National
Park in Bolivia). Prediction of the model can be confronted in the future to
data on vegetation patterns along environmental gradients as to anticipate the
possible effect of global change on those vegetation systems experiencing
constraining environmental conditions.Comment: 14 pages, 6figure
Timing, diagnosis, and treatment of surgical site infections after colonic surgery: prospective surveillance of 1263 patients
Surgical site infections (SSIs) are the most frequent complication after colorectal surgery and have a major impact on length of stay and costs.
To analyse the incidence, timing, and treatment of SSIs within 30 days after colonic surgery.
This was a quality improvement project through retrospective analysis of consecutive colonic surgeries between February 2012 and October 2017 at Lausanne University Hospital (CHUV). SSIs were prospectively assessed by an independent national surveillance programme (www.swissnoso.ch) up to 30 postoperative days. Treatment strategies including drainage of infection (direct wound opening or percutaneous) and surgical management were reviewed.
The study cohort included 1263 patients with 532 procedures (42%) performed as emergencies. SSIs were observed in 271 patients (21%), occurring at median postoperative day (POD) 9 (interquartile range (IQR): 4-16). Specifically, 53 (4%) were superficial incisional, 65 (5%) deep incisional, and 153 (12%) organ space infections (anastomotic insufficiency included). Superficial incisional SSI occurred at a median of POD 10.5 (IQR: 7-15), deep incisional at a median of POD 10 (8-15) and organ space at a median of POD 8 (5-11). Diagnosis was performed post discharge in 64 cases (24%). Whereas 47% of organ space infections were detected by POD 7, this rate was only 26% for superficial and deep incisional infections (P = 0.003). Surgical management was necessary in 133 cases (49%), and the remaining cases were managed by drainage without general anaesthesia (138 cases, 51%).
Organ space infections occurred early in the postoperative course, whereas incisional infections were mostly detected post discharge over the entire 30-day observation period, emphasizing the importance of proper follow-up using a systematic, complete and independent surveillance programme
Lower gastrointestinal bleeding-Computed Tomographic Angiography, Colonoscopy or both?
Lower endoscopy (LE) is the standard diagnostic modality for lower gastrointestinal bleeding (LGIB). Conversely, computed tomographic angiography (CTA) offers an immediate non-invasive diagnosis visualizing the entire gastrointestinal tract. The aim of this study was to compare these 2 modalities with regards to diagnostic value and bleeding control.
Tertiary center retrospective analysis of consecutive patients admitted for LGIB between 2006 and 2012. Comparison of patients with LE <i>vs.</i> CTA as first exam, respectively, with emphasis on diagnostic accuracy and bleeding control.
Final analysis included 183 patients; 122 (66.7%) had LE first, while 32 (17.5%) had CTA; 29 (15.8%) had neither of both exams. Median time to CTA was shorter compared to LE (3 (IQR = 8.2) <i>vs.</i> 22 (IQR = 36.9) hours, <i>P</i> < 0.001). Active bleeding was identified in 31% with CTA <i>vs.</i> 15% with LE ( <i>P</i> = 0.031); a non-actively bleeding source was found by CTA and LE in 22 <i>vs.</i> 31%, respectively ( <i>P</i> = 0.305). Bleeding control required endoscopy in 19%, surgery in 14% and embolization in 1.6%, while 66% were treated conservatively. Post-interventional bleeding was mostly controlled by endoscopic therapy (57%). 80% of patients with active bleeding on CTA required surgery.
Post-interventional LGIB was effectively addressed by LE. For other causes of LGIB, CTA was efficient, and more available than colonoscopy. Treatment was conservative for most patients. In case of active bleeding, CTA could localize the bleeding source and predict the need for surgery
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