460 research outputs found
Evidences of volcanic unrest on high-temperature fumaroles by satellite thermal monitoring: The case of Santa Ana volcano, El Salvador
International audienceOn October 1st, 2005, Santa Ana volcano (El Salvador) underwent a VEI 3 phreatomagmatic eruption after approximately one century of rest. Casualties and damages to some of the local infrastructures and surrounding plantations were followed by the evacuation of the nearby communities. The analysis of MODIS (Moderate Resolution Imaging Spectroradiometer) infrared data reveals that the main explosion was preceded by a one-year-long thermal unrest, associated to the development of a fumaroles field, located at the western rim of the summit crater lake. By combining space-based thermal flux and ground-based measurements (seismicity, sulfur emissions and lake temperatures), we suggest that the activity observed at Santa Ana between 2004 and 2005 was driven by the gradual intrusion of an undegassed magma body at a very shallow depth. Magma injection induced thermal anomalies associated with sustained degassing from the fumaroles field and promoted the interaction between the magmatic-hydrothermal system and the overlying water table. This process culminated into the VEI 3 phreatomagmatic eruption of October 2005 that strongly modified the shallow structure of the crater area. The subsequent three-years-long activity resulted from self-sealing of the fracture system and by the opening of a new fracture network directly connecting the deeper hydrothermal system with the crater lake. Our results show that satellite-based thermal data allow us to detect the expansion of the high-temperature fumarolic field. This may precede an explosive eruption and/or a lava dome extrusion. In particular, we show that thermal records can be analyzed with other geochemical (i.e. SO2 emissions) and geophysical (seismicity) data to track a shallow magmatic intrusion interacting with the surrounding hydrothermal system. This provides a remarkable support for volcano monitoring and eruption forecasting, particularly in remote areas where permanent ground data acquisition is hazardous, expensive and difficult
Determinación de Mercurio, Cadmio, Plomo y Arsénico en rÃos de la zona minera de la subcuenca del RÃo Titihuapa, Cabañas, El Salvador
La subcuenca del rÃo Titihuapa en el departamento de Cabañas alberga parte del vulcanismo Terciario de El Salvador en esa región, y por ende posee una abundancia de minerales. La actividad minera que se desarrolló desde finales del siglo XIX, hizo figurar a esta zona como una de las más propicias para la explotación de oro y plata en El Salvador. Sin embargo, esta prosperidad minera, pudo haber propiciado la contaminación metálica de buena parte de la cuenca del rÃo Titihuapa. La metodologÃa empleada incluyó la toma de muestras de sedimentos en sitios ubicados en los puntos de confluencia de los rÃos tributarios a la subcuenca Titihuapa, las cuales fueron resguardadas y transportadas al laboratorio para su respectivo análisis mediante técnicas de absorción atómica, método de horno de grafito y método de generador de flama. Se usó como parámetro el nivel de efectos leves (NEL) de la GuÃa Para la Evaluación de Sedimentos, del departamento de Protección Ambiental de New Jersey, 1998. Las concentraciones de Hg, Cd y Pb están por debajo de los valores de la NEL. Las concentraciones de As, la mayorÃa sobrepasa el NEL que es de 6.0 µg/g
Developing High Performance Lipoprotein Density Profiling for Use in Clinical Studies Relating to Cardiovascular Disease
Psychophysical Olfactory Tests and Detection of COVID-19 in Patients With Sudden Onset Olfactory Dysfunction: A Prospective Study
Objective: To investigate the coronavirus disease 2019 (COVID-19) status of patients with initial sudden olfactory anosmia (ISOA) through nasopharyngeal swabs for reverse transcription–polymerase chain reaction (RT-PCR) analysis and to explore their olfactory dysfunctions with psychophysical olfactory evaluation. Methods: A total of 78 ISOA patients were recruited from April 6, 2020, to April 10, 2020, through a public call of University of Mons (Mons, Belgium). Patients benefited from nasopharyngeal swabs and fulfilled the patient-reported outcome questionnaire. Among them, 46 patients performed psychophysical olfactory evaluation using olfactory identification testing. Based on the duration of the ISOA, 2 groups of patients were compared: patients with olfactory dysfunction duration ≤12 days (group 1) and those with duration >12 days (group 2). Results: In group 1, 42 patients (87.5%) had a positive viral load determined by RT-PCR and 6 patients (12.5%) were negative. In group 2, 7 patients (23%) had a positive viral load and 23 patients (77%) were negative. The psychophysical olfactory evaluation reported that anosmia and hyposmia occurred in 24 (52%) and 11 (24%) patients, respectively. Eleven patients were normosmic. The viral load was significantly higher in patients of group 1 compared with those of group 2. Conclusions: Coronavirus disease 2019 was detected in a high proportion of ISOA patients, especially over the first 12 days of olfactory dysfunction. Anosmia is an important symptom to consider in the detection of COVID-19 infection
Chemokine binding protein 'M3' limits atherosclerosis in apolipoprotein E-/- mice
Chemokines are important in macrophage recruitment and the progression of atherosclerosis. The 'M3' chemokine binding protein inactivates key chemokines involved in atherosclerosis (e.g. CCL2, CCL5 and CX3CL1). We aimed to determine the effect of M3 on plaque development and composition. In vitro chemotaxis studies confirmed that M3 protein inhibited the activity of chemokines CCL2, CCL5 and CX3CL1 as primary human monocyte migration as well as CCR2-, CCR5- and CX3CR1-directed migration was attenuated by M3. In vivo, adenoviruses encoding M3 (AdM3) or green fluorescence protein (AdGFP; control) were infused systemically into apolipoprotein (apo)-E-/- mice. Two models of atherosclerosis development were used in which the rate of plaque progression was varied by diet including: (1) a 'rapid promotion' model (6-week high-fat-fed) and (2) a 'slow progression' model (12-week chow-fed). Plasma chemokine activity was suppressed in AdM3-infused mice as indicated by significantly less monocyte migration towards AdM3 mouse plasma ex vivo (29.56%, p = 0.014). In the 'slow progression' model AdM3 mice had reduced lesion area (45.3%, p = 0.035) and increased aortic smooth muscle cell α-actin expression (60.3%, p = 0.014). The reduction in lesion size could not be explained by changes in circulating inflammatory monocytes as they were higher in the AdM3 group. In the 'rapid promotion' model AdM3 mice had no changes in plaque size but reduced plaque macrophage content (46.8%, p = 0.006) and suppressed lipid deposition in thoracic aortas (66.9%, p<0.05). There was also a reduction in phosphorylated p65, the active subunit of NF-κb, in the aortas of AdM3 mice (37.3%, p<0.0001). M3 inhibited liver CCL2 concentrations in both models with no change in CCL5 or systemic chemokine levels. These findings show M3 causes varying effects on atherosclerosis progression and plaque composition depending on the rate of lesion progression. Overall, our studies support a promising role for chemokine inhibition with M3 for the treatment of atherosclerosis.Dhanya Ravindran, Anisyah Ridiandries, Laura Z. Vanags, Rodney Henriquez, Siân Cartland, Joanne T. M. Tan, Christina A. Bursil
Biallelic JAK1 mutations in immunodeficient patient with mycobacterial infection
Mutations in genes encoding components of the immune system cause primary immunodeficiencies. Here, we study a patient with recurrent atypical mycobacterial infection and early-onset metastatic bladder carcinoma. Exome sequencing identified two homozygous missense germline mutations, P733L and P832S, in the JAK1 protein that mediates signalling from multiple cytokine receptors. Cells from this patient exhibit reduced JAK1 and STAT phosphorylation following cytokine stimulations, reduced induction of expression of interferon-regulated genes and dysregulated cytokine production; which are indicative of signalling defects in multiple immune response pathways including Interferon-γ production. Reconstitution experiments in the JAK1-deficient cells demonstrate that the impaired JAK1 function is mainly attributable to the effect of the P733L mutation. Further analyses of the mutant protein reveal a phosphorylation-independent role of JAK1 in signal transduction. These findings clarify JAK1 signalling mechanisms and demonstrate a critical function of JAK1 in protection against mycobacterial infection and possibly the immunological surveillance of cancer.Wellcome Trust (095198/Z/10/Z and 090233/Z/09/Z); Higher Education Funding Council for England; Great Ormond Street Hospital Children’s Charity; National Institute for Health Research (NIHR); Great Ormond Street Hospital Biomedical Research Centre; NIHR Cambridge Biomedical Research Centre; Alfonso Martin Escudero Foundatio
Centrality dependence of the expansion dynamics in Pb-Pb collisions at 158 A GeV/c
Two-particle correlation functions of negatively charged hadrons from Pb-Pb
collisions at 158 GeV/c per nucleon have been measured by the WA97 experiment
at the CERN SPS. A Coulomb correction procedure that assumes an expanding
source has been implemented. Within the framework of an expanding thermalized
source model the size and dynamical state of the collision fireball at
freeze-out have been reconstructed as a function of the centrality of the
collision. Less central collisions exhibit a different dynamics than central
ones: both transverse and longitudinal expansion velocities are slower, the
expansion duration is shorter and the system freezes out showing smaller
dimensions and higher temperature.Comment: 22 pages, 11 figures, Te
Previous Crop Sequences Effect on Fusarium Head Blight of Cereals in the Prairies
Non-Peer ReviewedFusarium head blight (FHB) is a disease of concern across the Canadian prairies; low crop diversity within rotations increases disease risk. Approximately 60% of the area seeded to annual crops in Alberta, Manitoba and Saskatchewan consists of wheat and canola. The present study focusses on the effect of previous crop sequences on the severity of FHB of cereals across the prairies. From 2018 to 2020, six locations were seeded with a core set of five crops including wheat, barley, canola, pea, and maize; at some sites, a sixth crop was included such as lentil. Each year, yield, crop quality and FHB severity were recorded; also, Fusarium spp. were isolated and identified from cereal kernels. Several Fusarium spp. caused FHB among cereal crops and were associated with host crops. The experiment consisted of a factorial arrangement in a split block design. The diversity criteria were established by using groups A, B, and C. Where A is the crop sequences that included cereals, pulses and oilseeds in the rotation. Treatment B, consisted of cereals and pulses, or cereals and oilseeds; while C, consisted only of cereals. This year data from Saskatoon shows that the diversity criteria played an important role in the proportion of the various Fusarium spp.. Fusarium spp. shows a significant difference between treatments and the frequency of F. graminearum isolated was similar in sequences with only cereals and cereal with pulses/ oilseeds, but both differed from a crop sequence that include three-different crops. The lack of crop diversity across western Canada is a risk factor for future disease outbreaks. Link to Video Presentation: https://youtu.be/zbUD6Lp7-c
Fishing for complementarities : competitive research funding and research productivity
This paper empirically investigates complementarities between different sources of research funding with regard to academic publishing. We find for a sample of UK engineering academics that competitive funding is associated with an increase in ex-post publications but that industry funding decreases the marginal utility of public funding by lowering the publication and citation rate increases associated with public grants. However, when holding all other explanatory variables at their mean, the negative effect of the interaction does not translate into an effective decrease in publication and citation numbers. The paper also shows that the positive effect of public funding is driven by UK research council and charity grants and that EU funding has no significant effect on publication outcomes
A hypoperfusion context may aid to interpret hyperlactatemia in sepsis-3 septic shock patients: a proof-of-concept study
__Background:__ Persistent hyperlactatemia is particularly difficult to interpret in septic shock. Besides hypoperfusion, adrenergic-driven lactate production and impaired lactate clearance are important contributors. However, clinical recognition of different sources of hyperlactatemia is unfortunately not a common practice and patients are treated with the same strategy despite the risk of over-resuscitation in some. Indeed, pursuing additional resuscitation in non-hypoperfusion-related cases might lead to the toxicity of fluid overload and vasoactive drugs. We hypothesized that two different clinical patterns can be recognized in septic shock patients through a multimodal perfusion monitoring. Hyperlactatemic patients with a hypoperfusion context probably represent a more severe acute circulatory dysfunction, and the absence of a hypoperfusion context is eventually associated with a good outcome. We performed a retrospective analysis of a database of septic shock patients with persistent hyperlactatemia after initial resuscitation.
__Results:__ We defined hypoperfusion context by the presence of a ScvO2 < 70%, or a P(cv-a)CO2 ≥6 mmHg, or a CRT ≥4 s together with hyperlactatemia. Ninety patients were included, of whom seventy exhibited a hypoperfusion-related pattern and 20 did not. Although lactate values were comparable at baseline (4.8 ± 2.8 vs. 4.7 ± 3.7 mmol/L), patients with a hypoperfusion context exhibited a more severe circulatory dysfunction with higher vasopressor requirements, and a trend to longer mechanical ventilation days, ICU stay, and more rescue therapies. Only one of the 20 hyperlactatemic patients without a hypoperfusion context died (5%) compared to 11 of the 70 with hypoperfusion-related hyperlactatemia (16%).
__Conclusions:__ Two different clinical patterns among hyperlactatemic septic shock patients may be identified according to hypoperfusion context. Patients with hyperlactatemia plus low ScvO2, or high P(cv-a)CO2, or high CRT values exhibited a more severe circulatory dysfunction. This provides a starting point to launch further prospective studies to confirm if this approach can lead to a more selective resuscitation strategy
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