272 research outputs found
Buck-boost dc voltage regulator
Circuit provides voltage regulation through a wide range of operating frequencies without intervals of high power dissipation
A low noise switching converter-regulator for main power control in a space power system
Variable ratio dc transformer regulator used to process main vehicle power from solar array battery power system in radio astronomy explorer spacecraf
Making the invisible, visible! Our daily mission!
This year, World Water Day celebrated Groundwater with the motto "Making the invisible, visible". Regardless of this particular recurrence, the one expressed by the motto represents the daily mission of every scholar or professional dedicated to groundwater. What is done through hydrogeological maps, through numerical models, through the development and interpretation of data series, tests in boreholes, wells and springs, what else is it, if not a way of visualizing this invisible underground resource? [...
The sustainable groundwater management and its contribution to a more resilient Rome
Groundwater , mapping, monitoring
Characterization of basal pseudopod-like processes in ileal and colonic PYY cells.
The peptide tyrosine tyrosine (PYY) is produced and secreted from L cells of the gastrointestinal mucosa. To study the anatomy and function of PYY-secreting L cells, we developed a transgenic PYY-green fluorescent protein mouse model. PYY-containing cells exhibited green fluorescence under UV light and were immunoreactive to antibodies against PYY and GLP-1 (glucagon-like peptide-1, an incretin hormone also secreted by L cells). PYY-GFP cells from 15 ÎĽm thick sections were imaged using confocal laser scanning microscopy and three-dimensionally (3D) reconstructed. Results revealed unique details of the anatomical differences between ileal and colonic PYY-GFP cells. In ileal villi, the apical portion of PYY cells makes minimal contact with the lumen of the gut. Long pseudopod-like basal processes extend from these cells and form an interface between the mucosal epithelium and the lamina propria. Some basal processes are up to 50 ÎĽm in length. Multiple processes can be seen protruding from one cell and these often have a terminus resembling a synapse that appears to interact with neighboring cells. In colonic crypts, PYY-GFP cells adopt a spindle-like shape and weave in between epithelial cells, while maintaining contact with the lumen and lamina propria. In both tissues, cytoplasmic granules containing the hormones PYY and GLP-1 are confined to the base of the cell, often filling the basal process. The anatomical arrangement of these structures suggests a dual function as a dock for receptors to survey absorbed nutrients and as a launching platform for hormone secretion in a paracrine fashion
The synthesis of decades of groundwater knowledge: the new Hydrogeological Map of Rome
This paper describes the contents and the path taken to get to the new Hydrogeological map of the City of Rome. The map, which is the result of a combination of "expert elaborations" and GIS processing performed using the most recent available data, extends to the entire municipality (1285 km2) and is based on both the most recent scientific studies on groundwater field and new survey activities carried out in order to fill the data gaps in several areas of the examined territory. The work represents also an example of inter-institutional collaboration between government agencies, research institutes and universities
Evolutionary dynamics of the cryptocurrency market
The cryptocurrency market surpassed the barrier of $100 billion market capitalization in June 2017, after months of steady growth. Despite its increasing relevance in the financial world, a comprehensive analysis of the whole system is still lacking, as most studies have focused exclusively on the behaviour of one (Bitcoin) or few cryptocurrencies. Here, we consider the history of the entire market and analyse the behaviour of 1469 cryptocurrencies introduced between April 2013 and May 2017. We reveal that, while new cryptocurrencies appear and disappear continuously and their market capitalization is increasing (super-)exponentially, several statistical properties of the market have been stable for years. These include the number of active cryptocurrencies, market share distribution and the turnover of cryptocurrencies. Adopting an ecological perspective, we show that the so-called neutral model of evolution is able to reproduce a number of key empirical observations, despite its simplicity and the assumption of no selective advantage of one cryptocurrency over another. Our results shed light on the properties of the cryptocurrency
market and establish a first formal link between ecological modelling and the study of this growing system. We anticipate they will spark further research in this direction
New hydrogeological results on the Groundwater Dependent Ecosystem of the Pilato Lake (Sibillini Mts, Central Italy)
Located at an altitude of about 1950 m a.s.l. in a glacial cirque of Mount Vettore (Monti Sibillini National Park - Central Italy), Pilato Lake is one of the few glacial lakes existing in the Apennines. Due to the endemic presence of the crustaceous Chirocephalus marchesonii, the Pilato Lake was in the past mainly studied from the biological viewpoint, but hydrogeological information on this groundwater dependent ecosystem is scarce. Furthermore, for investigating the lake drying in the recent 2017, 2019 and 2020 summers, the seasonal lowering of lake levels during 2010, 2012 and 2014-2020 was reconstructed. It resulted that in the preseismic years, the lake emptying was slower than in the post-seismic time. It is then supposed that seismic quaking induced an increase in permeability and, consequently, increased infiltration velocity through the lake sustaining surficial (detrital and glacial) and/or bedrock deposits towards the subsurface. More frequent summer dryings of the lake are then supposed for the next future. The hydrogeological conceptual model of the study area showed that the refilling process of the lake is driven by snow and rain precipitations. The air temperatures during 2017-2020 and their effects on evaporation from lake and on actual evapotranspiration were estimated. The infiltration through sustaining sediments was calculated and the estimation with time of lake wet surface and lake volume variations, and then bulk permeability of sustaining sediments, were evaluated as well
Il "Quaderno ISPRA-Servizio Geologico d'Italia, serie III, vol.14" con le Nuove linee guida al rilevamento e alla rappresentazione della Carta Idrogeologica d'Italia alla scala 1:50.000
Il cosiddetto "Quaderno 5" (Servizio Geologico Nazionale 1995; Quaderni serie III, volume 5), dedicato alle linee guida al rilevamento e alla rappresentazione della Carta Idrogeologica d'Italia scala 1:50.000, è piuttosto conosciuto, anche grazie ai suoi 25 anni di vita, ed è anche stato, almeno parzialmente, preso in considerazione per cartografie idrogeologiche elaborate da altre istituzioni (e.g. Boscherini et al. 2005; Celico et al. 2005; Civita et al. 2005; La Vigna e Mazza 2015). Proprio per la sua vetustà , i contenuti del Quaderno 5 attendevano di essere rivisti, anche in base ai risultati della discussione tecnico-scientifica proposta dal Servizio Geologico d'Italia dell'ISPRA nella seconda metà della prima decade del XXI secolo. Ma procediamo con ordine [...]
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