1,106 research outputs found

    Hydrological control of large hurricane-induced lahars: evidence from rainfall-runoff modeling, seismic and video monitoring

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    Abstract. The Volcán de Colima, one of the most active volcanoes in Mexico, is commonly affected by tropical rains related to hurricanes that form over the Pacific Ocean. In 2011, 2013 and 2015 hurricanes Jova, Manuel and Patricia, respectively, triggered tropical storms that deposited up to 400 mm of rain in 36 h, with maximum intensities of 50 mm h −1. The effects were devastating, with the formation of multiple lahars along La Lumbre and Montegrande ravines, which are the most active channels in sediment delivery on the south-southwest flank of the volcano. Deep erosion along the river channels and several marginal landslides were observed, and the arrival of block-rich flow fronts resulted in damages to bridges and paved roads in the distal reaches of the ravines. The temporal sequence of these flow events is reconstructed and analyzed using monitoring data (including video images, seismic records and rainfall data) with respect to the rainfall characteristics and the hydrologic response of the watersheds based on rainfall-runoff numerical simulation. For the studied events, lahars occurred 5–6 h after the onset of rainfall, lasted several hours and were characterized by several pulses with block-rich fronts and a maximum flow discharge of 900 m3 s −1. Rainfall-runoff simulations were performer using the SCS-curve number and the Green–Ampt infiltration models, providing a similar result in the detection of simulated maximum watershed peaks discharge. Results show different behavior for the arrival times of the first lahar pulses that correlate with the simulated catchment's peak discharge for La Lumbre ravine and with the peaks in rainfall intensity for Montegrande ravine. This different behavior is related to the area and shape of the two watersheds. Nevertheless, in all analyzed cases, the largest lahar pulse always corresponds with the last one and correlates with the simulated maximum peak discharge of these catchments. Data presented here show that flow pulses within a lahar are not randomly distributed in time, and they can be correlated with rainfall peak intensity and/or watershed discharge, depending on the watershed area and shape. This outcome has important implications for hazard assessment during extreme hydro-meteorological events, as it could help in providing real-time alerts. A theoretical rainfall distribution curve was designed for Volcán de Colima based on the rainfall and time distribution of hurricanes Manuel and Patricia. This can be used to run simulations using weather forecasts prior to the actual event, in order to estimate the arrival time of main lahar pulses, usually characterized by block-rich fronts, which are responsible for most of the damage to infrastructure and loss of goods and lives

    The Impact of Provider Websites on Patient Decision Making

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    It is imperative for health care providers to demonstrate performance excellence through a virtual exposure. Currently, providers use various online strategies to capture consumers’ attention, and by analyzing existing approaches, provider specific strategies will be identified that will enhance organizational virtual planning and increase market share. Achieving superiority by leveraging competitive advantage, highlighting recognitions, and eliminating wasteful information is vital from an operational and marketing perspective. By addressing patient questions and concerns through simplified website navigation, providers could ‘tip’ patient decision making in their favor. This research explores the importance and impact of the patient online experience and reveals current flaws on provider webpages

    Integration of optical and passive microwave satellite data for flooded area detection and monitoring

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    Flooding represents a serious threat to millions of people around the world and its hazard is rising as a result of climate changes. From this perspective, flood risk management is a key focus of many governments, whose priority is to have frequently updated and accurate information about the flood state and evolution to promptly react to the disaster and to put in place effective countermeasures devoted to limit damages and human lives losses. Remote sensing technology allows for flood monitoring at different spatial and temporal resolutions with an adequate level of accuracy. In particular, for emergency response purposes, an integrated use of satellite data, acquired by both optical and passive or active microwave instruments, has to be preferred to have more complete and frequently updated information on soil conditions and to better support decision makers. In this framework, multi-year time series of MODIS (Moderate Resolution Imaging Spectroradiometer) and AMSR-E (Advanced Microwave Scanning Radiometer for Earth Observing System) data were processed and analyzed. In detail, the Robust Satellite Techniques (RST), a multi-sensor approach for satellite data analysis, has been implemented for studying the August 2002 Elbe river flood occurred in Germany, trying to assess the potential of such an integrated system for the determination of soil status and conditions (i.e. moisture variation, water presence) as well as for a timely detection and a near real time monitoring of critical soil conditions

    In vitro antifungal activity and in vivo edible coating efficacy of insect-derived chitosan against Botrytis cinerea in strawberry

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    Strawberry is a perishable fruit, susceptible to development of rot by a range of fungi, in particular Botrytis cinerea. Chitosan represents an alternative to agrochemicals for improving shelf-life and fighting fungal pathogens. A chitosan-based coating derived from pupal exuviae of Hermetia illucens has been recently formulated for improving shelf-life of strawberry stored at 4 °C and mixed condition (4 °C and room temperature). The effects of a decolored (PEDEC) and not decolored (PEND) chitosan from the black soldier fly were evaluated and compared with commercial chitosans from crustaceans (CCs), in vitro and in vivo. An inhibition/reduction of fungal growth and a disturbance of normal fungal morphology were observed, being MIC of 0.5 mg mL−1 and 1 mg mL−1 and growth inhibition of 70 % and 4% for PEND and PEDEC, respectively. Both edible coatings distributed via aerograph showed equal or better potential application than CCs in controlling B. cinerea in strawberry post-harvest treated. Different effects for chitosans depended on their different molecular weight and deacetylation degree distributions, and the presence or absence of melanin pigments in their structure. PEND could act directly against the fungus, with effects predominantly associated with fungitoxic properties; PEDEC might principally provide viable alternatives, such as the elicitation of biochemical defense responses in fruits, for example through total phenols, in particular the flavonoids

    AMPK Activators as Novel Drug Candidates for the Treatment of Inflammatory Bowel Diseases

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    Inflammatory bowel diseases (IBDs), mainly represented by ulcerative colitis and Crohn’s disease, are chronic and idiopathic diseases of the digestive tract. They incidence and prevalence is raising significantly in both developed and developing countries, thus representing a major challenge for the worldwide healthcare systems. The pharmacological armamentarium for the treatment of IBDs is far from being satisfactory, as the therapeutic success of the available drugs is still limited. Accordingly, the development of novel and effective compounds is highly requested. In this context, the serine/threonine heterotrimeric kinase AMPK (adenosine monophosphate-activated protein kinase) seems a sound target to strike. Known as the central hub of energy homeostasis in eukaryotic cells, AMPK contributes also to the modulation of immune/inflammatory cell functions. Actually, alterations in AMPK expression and/or activity play a key role in the pathophysiology of immune-mediated inflammatory diseases characterized by abnormal immune cell functions, like IBDs. Moreover, AMPK is able to improve intestinal health by enhancing para-cellular junctions, nutrient transporters, autophagy and apoptosis. Accordingly, AMPK activation represents a promising therapeutic strategy for the treatment of intestinal inflammatory disorders. Here we describe a novel heterocyclic derivative, developed as AMPK activator. Tested in C2C12 myoblast cell lines, our compound significantly increased AMPK activity, in a concentration-dependent manner, turning out to be more effective than the well-known activator acadesine (ACA). Moreover, assayed in a mouse model of acute DNBS-induced colitis, the novel heterocycle displayed a relevant anti-inflammatory efficacy, proving to ameliorate both systemic- and tissue-related inflammatory parameters like body and spleen weight, colon length, macroscopic damage, TNF and MDA levels. Also in this case, our compound turned out to be significantly more active that the known reference ACA, thus imposing itself as a novel and valuable drug candidate for the treatment of IBDs
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