1,029 research outputs found
Fractional differentiability for solutions of nonlinear elliptic equations
We study nonlinear elliptic equations in divergence form
When
has linear growth in , and assuming that enjoys smoothness, local
well-posedness is found in for certain values of
and . In the particular case
, and ,
, we obtain for each
. Our main tool in the proof is a more general result, that
holds also if has growth in , , and
asserts local well-posedness in for each , provided that
satisfies a locally uniform condition
A tool for evaluating geothermal power exploitability and its application to Ischia, Southern Italy
The paper proposes a method to evaluate the potential for electric power production at any site of possible
geothermal interest. Accounting for geological data of the reservoirs, the method allows the computation
of the available electrical power of the investigated site. Electrical energy production from geothermal
sources is realized through different techniques, such as single flash and double flash, dry steam, and binary
ORC plants. The technique chosen to be the most productive is determined by analyzing a specific range of geofluid properties, mainly temperature and pressure. Moreover, each plant typology has a global efficiency that may be correlated to geofluid enthalpy by empiric relations available in literature. The proposed evaluation method brings together all these correlations, yielding the power availability from a geosource, once its temperature and pressure are known. The method takes as input the geofluid available flow rate, its pressure, temperature and non-condensable gas content. It defines the best plant option from these parameters, calculates its global efficiency and finally returns the actual available power. For sites of geothermic interest, such as the volcanic island of Ischia in Southern Italy, the results of the application of this new method clearly highlight the most suitable zones for power plants installations
Can Quantum de Sitter Space Have Finite Entropy?
If one tries to view de Sitter as a true (as opposed to a meta-stable)
vacuum, there is a tension between the finiteness of its entropy and the
infinite-dimensionality of its Hilbert space. We invetsigate the viability of
one proposal to reconcile this tension using -deformation. After defining a
differential geometry on the quantum de Sitter space, we try to constrain the
value of the deformation parameter by imposing the condition that in the
undeformed limit, we want the real form of the (inherently complex) quantum
group to reduce to the usual SO(4,1) of de Sitter. We find that this forces
to be a real number. Since it is known that quantum groups have
finite-dimensional representations only for root of unity, this suggests
that standard -deformations cannot give rise to finite dimensional Hilbert
spaces, ruling out finite entropy for q-deformed de Sitter.Comment: 10 pages, v2: references added, v3: minor corrections, abstract and
title made more in-line with the result, v4: published versio
Hydrothermal fluid venting in the offshore sector of Campi Flegrei caldera: A geochemical, geophysical, and volcanological study
The ongoing unrest at the Campi Flegrei caldera (CFc) in southern Italy is prompting exploration
of its poorly studied offshore sector. We report on a multidisciplinary investigation of the Secca delle
Fumose (SdF), a submarine relief known since antiquity as the largest degassing structure of the offshore
sector of CFc. We combined high-resolution morphobathymetric and seismostratigraphic data with onshore
geological information to propose that the present-day SdF morphology and structure developed during
the initial stages of the last CFc eruption at Monte Nuovo in AD 1538. We suggest that the SdF relief stands
on the eastern uplifted border of a N-S-trending graben-like structure formed during the shallow emplacement
of the Monte Nuovo feeding dike. We also infer that the high-angle bordering faults that generated
the SdF relief now preferentially allow the ascent of hot brines (with an equilibrium temperature of 1798C),
thereby sustaining hydrothermal degassing on the seafloor. Systematic vertical seawater profiling shows
that hydrothermal seafloor venting generates a sizeable CO2, pH, and temperature anomaly in the overlying
seawater column. Data for the seawater vertical profile can be used to estimate the CO2 and energy (heat)
outputs from the SdF area at 50 tons/d (0.53 kg/s) and 80 MW, respectively. In view of the cause-effect
relationship with the Monte Nuovo eruption, and the substantial gas and energy outputs, we consider that
the SdF hydrothermal system needs to be included in monitoring programs of the ongoing CFc unrest
Nose-pharyngeal swabs as a screening test for SARS-CoV-2 infection in patients with scheduled elective surgery. The experience of the Hygiene Service of Local Health Authority Roma 1
Proactive case investigation and contact tracing, testing, home isolation, in parallel with systematic home care for patients with mild symptoms have served as cornerstones of a territorial response strategy, where an established network of public health and primary care services existed. The Italian National Health Service (NHS) entrusts many management competences to the Regions, with the result of a different management of the Covid-19 epidemic between the Regions and sometimes even among the Local Health Authorities (LHAs - in Italian: Aziende Sanitarie Locali). In Italy, the Department of Prevention (DP) plays a pivotal role in structuring the collaboration between territorial health services, hospitals and all the network of the NHS. DP is the technical structure of LHA, with the task of promoting health, preventing the onset of disease and improving the quality of life of the population. The Covid-19 pandemic has had a considerable impact on the DPs, which have necessarily had to reorganize their services in a very short time in order to provide an appropriate response to the renewed health concerns
DNA damage response at telomeres boosts the transcription of SARS-CoV-2 receptor ACE2 during aging
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes the coronavirus disease 2019 (COVID-19), known to be more common in the elderly, who also show more severe symptoms and are at higher risk of hospitalization and death. Here, we show that the expression of the angiotensin converting enzyme 2 (ACE2), the SARS-CoV-2 cell receptor, increases during aging in mouse and human lungs. ACE2 expression increases upon telomere shortening or dysfunction in both cultured mammalian cells and in vivo in mice. This increase is controlled at the transcriptional level, and Ace2 promoter activity is DNA damage response (DDR)-dependent. Both pharmacological global DDR inhibition of ATM kinase activity and selective telomeric DDR inhibition by the use of antisense oligonucleotides prevent Ace2 upregulation following telomere damage in cultured cells and in mice. We propose that during aging telomere dysfunction due to telomeric shortening or damage triggers DDR activation and this causes the upregulation of ACE2, the SARS-CoV-2 cell receptor, thus contributing to make the elderly more susceptible to the infection
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