A nonlocal supercritical Neumann problem

We establish existence of positive non-decreasing radial solutions for a nonlocal nonlinear Neumann problem both in the ball and in the annulus. The nonlinearity that we consider is rather general, allowing for supercritical growth (in the sense of Sobolev embedding). The consequent lack of compactness can be overcome, by working in the cone of non-negative and non-decreasing radial functions. Within this cone, we establish some a priori estimates which allow, via a truncation argument, to use variational methods for proving existence of solutions. As a side result, we prove a strong maximum principle for nonlocal Neumann problems, which is of independent interest.Comment: 32 pages, 0 figure

Existence and non-existence results for a semilinear fractional Neumann problem

We establish a priori $L^\infty$-estimates for non-negative solutions of a semilinear nonlocal Neumann problem. As a consequence of these estimates, we get non-existence of non-constant solutions under suitable assumptions on the diffusion coefficient and on the nonlinearity. Moreover, we prove an existence result for radial, radially non-decreasing solutions in the case of a possible supercritical nonlinearity, extending to the case $0<s\le 1/2$ the analysis started in [7].Comment: 17 pages, accepted version: minor changes from the original manuscrip

Existence and non-existence results for a semilinear fractional Neumann problem

We establish a priori $L^\infty$-estimates for non-negative solutions of a semilinear nonlocal Neumann problem. As a consequence of these estimates, we get non-existence of non-constant solutions under suitable assumptions on the diffusion coefficient and on the nonlinearity. Moreover, we prove an existence result for radial, radially non-decreasing solutions in the case of a possible supercritical nonlinearity, extending to the case $

Earthquake effects and insights on fault activity at the Beatrice Cenci cave (Abruzzo, Central Apennines)

he focus of this study is the analysis of a cave in Central Italy, the Beatrice Cenci cave, in order to point out and constrain evidence of possible past earthquakes and of fault activity in the area. We performed a survey of seismic related damages within the cave. This included the analysis of broken/collapsed speleothems, the recognition of structural collapse, of tilting/growth alteration in the speleothems, and the mapping of fractures, joints and/or faults. To timely set the occurrence of the recognized damage, organic sediments were dated with 14C radiocarbon method. The results merged toward the recognition of two distinct seismic shaking events affecting the cave environment, one older than 30 kyr and another around 7 kyr. The deformation observed within the cave led us to the hypothesis that the events of damage were possibly linked to the activity of the regional tectonic lineament that crosses the cave, i.e., the Liri normal fault. The morphology and the evolution of the cave appear controlled by the fault zone. These speleoseismological results provided a new contribution on the knowledge of the past activity of the Liri fault and on the earthquake history of this sector of Central Apennines

Animal Forest Mortality: Following the Consequences of a Gorgonian Coral Loss on a Mediterranean Coralligenous Assemblage

In this work, the consequences of a local gorgonian coral mortality on the whole coralligenous assemblage were studied. A Before/After-Control/Impact sampling design was used: the structure of the coralligenous assemblage was compared before and after the gorgonian mortality event at the mortality site and two control sites. At the mortality site, a relevant decrease in alpha and beta diversity occurred, with a shift from a stratified assemblage characterized by gorgonians and other invertebrates to an assemblage dominated by algal turfs; conversely, neither significant variations of the structure nor decrease in biodiversity were observed at the control sites. The assemblage shift involved the main taxa in different times: in autumn 2018, a large proportion of the plexaurid coral Paramuricea clavata died, but no significant changes were observed in the structure of the remaining assemblage. Then, in autumn 2019, algal turfs increased significantly and, one year later, the abundance of the gorgonian Eunicella cavolini and bryozoans collapsed. Although the mechanisms of the assemblage shift following gorgonian loss will remain uncertain and a cause-effect relationship cannot be derived, results suggest the need for detecting signs of gorgonian forests stress in monitoring programs, which should be considered early indicators of their condition. in the coralligenous monitoring programs for detecting any sign of gorgonian forests stress which should be considered an early indicator of the assemblage condition

Chronostratigraphic study of the Grottaperfetta alluvial valley in the city of Rome (Italy): investigating possible interaction between sedimentary and tectonic processes

We carried out geomorphologic and geological investigations in a south-eastern tributary valley of the Tiber River in Rome, the Grottaperfetta valley, aimed to reconstruct its buried geometry. Since results of the geomorphologic study evidenced anomalies of the stream beds, we performed geoelectric and boreholes prospecting to check whether recent faulting, rather than an inherited structural control, possibly contributed to the evolution of the alluvial valley. Vertical offsets of the stratigraphic horizons across adjacent boreholes were evidenced within the Late Pleistocene-Holocene alluvium and its substratum. In order to rule out the effects of irregular geometry of the alluvial deposits, we focussed on sectors where vertical offsets affected all the stratigraphic horizons (alluvium and pre-Holocene substratum), showing an increasing displacement with depth. We identified a site where repeated displacements occur coupled with a lateral variation of soil resistivity, and we drilled an oblique borehole aimed to cross and sample the possible fault zone affecting the terrain. A 7 cm thick granular layer, inclined 50°÷70° on the horizontal, was recovered 5 m b.g., and it was interpreted as the filling material of a fracture. The convergence of the reported features with independent evidence from geoelectric and geomorphologic investigations leads to hypothesize the presence of a faulting zone within the Holocene alluvial terrains and to propose the excavation of a trench to verify this hypothesis

Androgens and Adipose Tissue in Males: A Complex and Reciprocal Interplay

Clinical evidence shows that in males obesity is frequently associated with hypogonadism and vice versa; also, low testosterone levels have been considered a “hallmark” of metabolic syndrome in men. These observations indicate that there is a strict connection between anatomically and functionally distinct cell types such as white adipocytes and Leydig cells, that synthesize testosterone. Adipose tissue is able to control several functions of the testis through its products secreted in the bloodstream. On the other hand, circulating levels of testosterone and estradiol deeply affect adipocyte proliferation, differentiation, and fat mass distribution, hereby controlling critical metabolic functions, such as food intake, insulin sensitivity, vascular reactivity, and immunity. This paper highlights the existing clinical and experimental evidence linking androgens and adipose tissue and illustrates the consequences occurring when the balance between fat mass distribution and eugonadism is lost

New trenching results along the İznik segment of the central strand of the North Anatolian Fault (Turkey): an integration with preexisting data

AbstractThis paper provides a new contribution to the construction of the complex and fragmentary mosaic of the Late Holocene earthquakes history of the İznik segment of the central strand of the North Anatolian Fault (CNAF) in Turkey. The CNAF clearly displays lower dextral slip rates with respect to the northern strand however, surface rupturing and large damaging earthquakes (M > 7) occurred in the past, leaving clear signatures in the built and natural environments. The association of these historical events to specific earthquake sources (e.g., Gemlik, İznik, or Geyve fault segments) is still a matter of debate. We excavated two trenches across the İznik fault trace near Mustafali, a village about 10 km WSW of İznik where the morphological fault scarp was visible although modified by agricultural activities. Radiocarbon and TL dating on samples collected from the trenches show that the displaced deposits are very recent and span the past 2 millennia at most. Evidence for four surface faulting events was found in the Mustafali trenches. The integration of these results with historical data and previous paleoseismological data yields an updated Late Holocene history of surface-rupturing earthquakes along the İznik Fault in 1855, 740 (715), 362, and 121 CE. Evidence for the large M7 + historical earthquake dated 1419 CE generally attributed to this fault, was not found at any trench site along the İznik fault nor in the subaqueous record. This unfit between paleoseismological, stratigraphic, and historical data highlights one more time the urge for extensive paleoseismological trenching and offshore campaigns because of the high potential to solve the uncertainties on the seismogenic history (age, earthquake location, extent of the rupture and size) of this portion of NAFZ and especially on the attribution of historical earthquakes to the causative fault

Impact assessment of fish cages on coralligenous reefs through the use of the STAR sampling procedure

The study aimed at contributing to the development of methods to assessing the effects of human disturbance on coralligenous reefs. The effects of the presence of a fish farm on coralligenous reefs were evaluated using the STAR (STAndaRdized coralligenous evaluation procedure) sampling procedure. An asymmetrical sampling design was used to compare the aquaculture site with two reference sites in areas unaffected by human pressure. The response of different ecological indices (ESCA, Ecological Status of Coralligenous Assemblages; ISLA, Integrated Sensitivity Level of coralligenous Assemblages; COARSE, COralligenous Assessment by Reef Scape Estimate) and descriptors (α-diversity, β-diversity and Sensitivity Level) of this kind of disturbance was compared. Results indicate that coralligenous reefs are vulnerable to aquaculture fish cages, and differences in the structure of coralligenous assemblages between the disturbed and the reference sites were mostly due to the decrease in β-diversity. On the contrary, no significant differences in the number of taxa/groups were highlighted. Encrusting Corallinales, erect Rhodophyta, Dictyotales, Fucales and Halimeda tuna were more abundant in reference sites than in disturbed site, while Peyssonnelia spp. and algal turfs had the opposite trend. Conversely, no significant differences between conditions were found in the abundance of sessile invertebrates. The study supports the suitability of the STAR approach to be employed in impact evaluation assessments, such as in monitoring programs. The present study is a first attempt to combine three different ecological indices (ESCA, ISLA and COARSE) within a unified approach, in order to assess the status of coralligenous reefs subjected to a moderate human-induced disturbance. The inconsistent response of the different indices highlights the advantage of applying different indices and descriptors to evaluate the variable human pressures on natural systems

The August 17, 1999 Izmit, Turkey, earthquake: slip distribution from dislocation modeling of DInSAR and surface offset

We show the results of application of Differential SAR Interferometry to the MW 7.4, August 17, 1999, Izmit earthquake, Western Turkey. The differential interferogram is obtained using an interferometric ERS2 ascending pair with a time interval of 35 days (August 13th - September 17th). The fringe pattern clearly defines the coseismic displacement field extended in an area of about 100 km N-S and 120 km E-W. The analysis of the interferogram shows the right-lateral strike-slip movement on the activated section of the North Anatolian fault system. The maximum SAR-detected displacement ranges between 117.6 cm and 134.4 cm in the proximity of Gölcük. We invert SAR data for uniform dislocation on a single fault plane using a Montecarlo procedure, with the aim of testing a large set of a priori possible asperity distributions on the fault. We then use a forward modeling approach to evaluate the slip variability for the dislocation using additional constraints as surface offsets and seismicity distribution: in this case we allow unit cells to undergo different values of slip in order to refine the initial dislocation model. Misfits between SAR data and modeled slant range displacements are generally low for all our models (~ 12 cm). Our results indicate that slip is concentrated in the central-western part of the fault, in the upper 10-15 km, tapering to the fault tips. For the Izmit case, we note that a well constrained fault model can be obtained only integrating DInSAR data with additional observations. This is mainly due to an undersampling of the displacement field by DInSAR, caused by decorrelation and lack of image data