3,646 research outputs found
QVAST: a new Quantum GIS plugin for estimating volcanic susceptibility
One of the most important tasks of modern volcanology is the construction of hazard maps simulating different eruptive scenarios that can be used in risk-based decision
making in land-use planning and emergency management.
The first step in the quantitative assessment of volcanic hazards is the development of susceptibility maps (i.e., the spatial probability of a future vent opening given the past eruptive activity of a volcano). This challenging issue is generally
tackled using probabilistic methods that use the calculation of a kernel function at each data location to estimate probability density functions (PDFs). The smoothness and the modeling ability of the kernel function are controlled by the smoothing parameter, also known as the bandwidth. Here we present a new tool, QVAST, part of the open-source geographic information system Quantum GIS, which is designed to create user-friendly quantitative assessments of volcanic susceptibility. QVAST allows the selection of an appropriate method for evaluating the bandwidth for the kernel function on the basis of the input parameters and the shapefile geometry, and can also evaluate the PDF with the Gaussian kernel. When different input data sets are available for the area,
the total susceptibility map is obtained by assigning different weights to each of the PDFs, which are then combined via a weighted summation and modeled in a non-homogeneous
Poisson process. The potential of QVAST, developed in a free and user-friendly environment, is here shown through its application in the volcanic fields of Lanzarote (Canary Islands) and La Garrotxa (NE Spain)
Disease Activity and Progression in Multiple Sclerosis: New Evidences and Future Perspectives
Multiple sclerosis (MS) is a chronic, debilitating, autoimmune-mediated, inflammatory disease of the central nervous system (CNS), in which a combination of inflammation, demyelination and axonal degeneration takes place with extreme highly interpersonal variability [...]
Rehabilitation strategies for low anterior resection syndrome. A systematic review
OBJECTIVE: To summarize the evidence in the literature about rehabilitative treatments that reduce low anterior resection syndrome (LARS) symptoms in patients who underwent surgery for colorectal cancer. METHODS: We have search in PubMed, Cochrane Central Register of Controlled Trials, Cumulative Index of Nursing and Allied Health and Scopus databases. Studies selected were limited to those including only patient undergone low rectal resection with sphincter preservation and with pre-post assessment with a LARS score. Five articles fit the criteria. RESULTS: The percutaneous tibial nerve stimulation demonstrated moderate results and sacral nerve stimulation was found to be the best treatment with greater symptom improvement. Only one study considered sexual and urinary problems in the outcomes assessment. CONCLUSIONS: In clinical practice patients should evaluate with the LARS and other score for evaluation of urinary and sexual problems. Future research must be implemented with higher quality studies to identify the least invasive and most effective treatment/s
Discrete derivatives and symmetries of difference equations
We show on the example of the discrete heat equation that for any given
discrete derivative we can construct a nontrivial Leibniz rule suitable to find
the symmetries of discrete equations. In this way we obtain a symmetry Lie
algebra, defined in terms of shift operators, isomorphic to that of the
continuous heat equation.Comment: submitted to J.Phys. A 10 Latex page
Organotypic slice cultures containing the preBotzinger complex generate respiratory-like rhythms
Study of acute brain stem slice preparations in vitro has advanced our understanding of the cellular and synaptic mechanisms of respiratory rhythm generation, but their inherent limitations preclude long-term manipulation and recording experiments. In the current study, we have developed an organotypic slice culture preparation containing the preBotzinger complex (preBotC), the core inspiratory rhythm generator of the ventrolateral brain stem. We measured bilateral synchronous network oscillations, using calcium-sensitive fluorescent dyes, in both ventrolateral (presumably the preBotC) and dorsomedial regions of slice cultures at 7-43 days in vitro. These calcium oscillations appear to be driven by periodic bursts of inspiratory neuronal activity, because whole cell recordings from ventrolateral neurons in culture revealed inspiratory-like drive potentials, and no oscillatory activity was detected from glial fibrillary associated protein-expressing astrocytes in cultures. Acute slices showed a burst frequency of 10.9 +/- 4.2 bursts/min, which was not different from that of brain stem slice cultures (13.7 +/- 10.6 bursts/min). However, slice cocultures that include two cerebellar explants placed along the dorsolateral border of the brainstem displayed up to 193% faster burst frequency (22.4 +/- 8.3 bursts/min) and higher signal amplitude (340%) compared with acute slices. We conclude that preBotC-containing slice cultures retain inspiratory-like rhythmic function and therefore may facilitate lines of experimentation that involve extended incubation (e.g., genetic transfection or chronic drug exposure) while simultaneously being amenable to imaging and electrophysiology at cellular, synaptic, and network levels
Role of Synaptic Inhibition in the Coupling of the Respiratory Rhythms that Underlie Eupnea and Sigh Behaviors
The preBötzinger complex (preBötC) gives rise to two types of breathing behavior under normal physiological conditions: eupnea and sighing. Here, we examine the neural mechanisms that couple their underlying rhythms. We measured breathing in awake intact adult mice and recorded inspiratory rhythms from the preBötC in neonatal mouse brainstem slice preparations. We show previously undocumented variability in the temporal relationship between sigh breaths or bursts and their preceding eupneic breaths or inspiratory bursts. Investigating the synaptic mechanisms for this variability in vitro, we further show that pharmacological blockade of chloride-mediated synaptic inhibition strengthens inspiratory-to-sigh temporal coupling. These findings contrast with previous literature, which suggested glycinergic inhibition linked sigh bursts to their preceding inspiratory bursts with minimal time intervals. Furthermore, we verify that pharmacological disinhibition did not alter the duration of the prolonged interval that follows a sigh burst before resumption of the inspiratory rhythm. These results demonstrate that synaptic inhibition does not enhance coupling between sighs and preceding inspiratory events or contribute to post-sigh apneas. Instead, we conclude that excitatory synaptic mechanisms coordinate inspiratory (eupnea) and sigh rhythms
trans-K3[TcO2(CN)4]
The structure of the title compound, tripotassium trans-tetraÂcyanidodioxidotechnetate(V), is isotypic with its Re analogue. The [TcO2(CN)4]3â
trans-tetraÂcyanidoÂdioxidoÂtechnetate anion has a slightly distorted octaÂhedral configuration. The Tc atom is located on a center of inversion and is bound to two O atoms in axial and to four cyanide ligands in equatorial positions. The TcâO distance is consistent with a double-bond character. The two potassium cations, one located on a center of inversion and one in a general position, reside in octaÂhedral or tetraÂhedral environments, respectively. KâŻO and KâŻN interÂactions occur in the 2.7877â
(19)â2.8598â
(15)â
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range
Hospital Malnutrition and Inflammatory Response in Critically Ill Children and Adolescents Admitted to a Tertiary Intensive Care Unit
Critical illness has a major impact on the nutritional status of both children and adults. A retrospective study was conducted to evaluate the incidence of hospital malnutrition at a pediatric tertiary intensive care unit (PICU). Serum concentrations of IL-6 in subgroups of well-nourished and malnourished patients were also evaluated in an attempt to identify those with a potential nutritional risk
Transcriptomes of Electrophysiologically Recorded Dbx1-derived Respiratory Neurons of the preBötzinger Complex in Neonatal Mice
Breathing depends on interneurons in the preBötzinger complex (preBötC) derived from Dbx1-expressing precursors. Here we investigate whether rhythm- and pattern-generating functions reside in discrete classes of Dbx1 preBötC neurons. In a slice model of breathing withâ~â5 s cycle period, putatively rhythmogenic Type-1 Dbx1 preBötC neurons activate 100â300 ms prior to Type-2 neurons, putatively specialized for output pattern, and 300â500 ms prior to the inspiratory motor output. We sequenced Type-1 and Type-2 transcriptomes and identified differential expression of 123 genes including ionotropic receptors (Gria3, Gabra1) that may explain their preinspiratory activation profiles and Ca2+ signaling (Cracr2a, Sgk1) involved in inspiratory and sigh bursts. Surprisingly, neuropeptide receptors that influence breathing (e.g., ”-opioid and bombesin-like peptide receptors) were only sparsely expressed, which suggests that cognate peptides and opioid drugs exert their profound effects on a small fraction of the preBötC core. These data in the public domain help explain the neural origins of breathing
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