94 research outputs found
Normal approximation of Random Gaussian Neural Networks
In this paper we provide explicit upper bounds on some distances between the
(law of the) output of a random Gaussian NN and (the law of) a random Gaussian
vector. Our results concern both shallow random Gaussian neural networks with
univariate output and fully connected and deep random Gaussian neural networks,
with a rather general activation function. The upper bounds show how the widths
of the layers, the activation functions and other architecture parameters
affect the Gaussian approximation of the ouput. Our techniques, relying on
Stein's method and integration by parts formulas for the Gaussian law, yield
estimates on distances which are indeed integral probability metrics, and
include the total variation and the convex distances. These latter metrics are
defined by testing against indicator functions of suitable measurable sets, and
so allow for accurate estimates of the probability that the output is localized
in some region of the space. Such estimates have a significant interest both
from a practitioner's and a theorist's perspective
Trophic overlap between wolves and free-ranging wolf Ă dog hybrids in the Apennine Mountains, Italy
Hybridization between wolves (Canis lupus) and domestic dogs (Canis familiaris) can represent a threat to wild populations via genetic introgression and ecological competition. Therefore understanding the ecological role of hybrids may be crucial for developing appropriate conservation strategies. The Italian wolf population has a peculiar genetic composition due to a long-lasting geographic isolation. Nowadays, however, its genetic integrity is threatened by the spread of canine genes as a result of the hybridization with stray dogs in the wild. The aim of the present study was to gain insights into the ecological role of free-ranging wolfâdog hybrids by investigating their winter food habits in comparison with wolves in a mountain area of Central Italy. Levels of genetic introgression from the dogs were assessed in two adjacent areas occupied by up to five different packs by analyzing non-invasive samples and carcasses collected therein with a set of uniparental and bi-parental molecular markers. The obtained results enabled us to classify the two areas as 'hybrid' and 'wolf' areas based on their level of genetic introgression. Trophic niche and similarity/dissimilarity analyses did not detect significant difference in the diet between the two areas: in both of them, wild boar was the main prey, followed by roe deer. Furthermore, the same age/body mass classes of the two ungulates were selected by wolves and hybrids. Our findings confirmed wolfâdog hybrids as potential competitors for wolves. Further studies on other aspects of their biology and ecology are recommended in order to better estimate the impact of hybridization on natural wolf populations
Early and long-term impacts of browsing by roe deer in oak coppiced woods along a gradient of population density
Over the last few decades, wild ungulate populations have exhibited relevant geographic and demographic expansion in most European countries; roe deer is amongst the most widespread ungulate species. The increasing roe deer densities have led to strong impact on forest regeneration; the problem has been recently recognized in coppice woods, a silvicultural system which is widespread in Italy, where it amounts to about 56% of the total national forested area.In this study we investigated the effect of roe deer browsing on the vegetative regeneration of Turkey oak few years after coppicing, along a gradient of roe deer density. A browsing index revealed that browsing impact was high at any given roe deer density but increased at higher density, with the browsing rate ranging from 65% to 79%. We also analyzed the long-term impact of browsing six and eleven years after coppicing under a medium roe deer density. Results indicated the early impact are not ephemeral but produced prolonged impacts through time, with an average reduction in volume of -57% and -41% six and eleven years after coppicing, respectively. Based on these results we proposed integrating browsing monitoring with roe deer density estimation to allow identifying ungulate densities which are compatible with silvicultural and forest management objectives. The proposed browsing index can be regarded as an effective management tool, on account of its simplicity and cost-effectiveness, being therefore highly suitable for routine, large scale monitoring of browsing impact
SACHER Project: A Cloud Platform and Integrated Services for Cultural Heritage and for Restoration
The SACHER project provides a distributed, open source and federated cloud platform able to support the life-cycle management of various kinds of data concerning tangible Cultural Heritage. The paper describes the SACHER platform and, in particular, among the various integrated service prototypes, the most important ones to support restoration processes and cultural asset management: (i) 3D Life Cycle Management for Cultural Heritage (SACHER 3D CH), based on 3D digital models of architecture and dedicated to the management of Cultural Heritage and to the storage of the numerous data generated by the team of professionals involved in the restoration process; (ii) Multidimensional Search Engine for Cultural Heritage (SACHER MuSE CH), an advanced multi-level search system designed to manage Heritage data from heterogeneous sources
Barriers to psychological help-seeking in young men who have attempted suicide : an interpretative phenomenological analysis
The current paper reviews literature on help-seeking in relation to suicide and attempted suicide. An overview of the extensive research into risk factors associated with suicide is given highlighting the link between mental health problems and suicide. A minority of people with mental health problems seek professional help and even fewer people will go on to receive help from specialist mental health services. The same pattern is seen in those at risk of suicide. The majority will not be receiving specialist support at the time of their death although about half will have had recent contact with their GP. Reasons for not seeking help in times of emotional distress are discussed. Finally, clinical implications arising from the literature are addressed and suggestions are made for future research
A multicenter retrospective cohort study evaluating the clinical outcomes of patients with coagulopathy undergoing transcatheter arterial embolization (tae) for acute non-neurovascular bleeding
Background and Objectives: Transcatheter arterial embolization (TAE) is the mainstay of
treatment for acute major hemorrhage, even in patients with coagulopathy and spontaneous bleeding.
Coagulopathy is associated with worsening bleeding severity and higher mortality and clinical failure
rates. Furthermore, some unanswered questions remain, such as the definition of coagulopathy, the
indication for TAE or conservative treatment, and the choice of embolic agent. This study aims to
assess the efficacy and safety of TAE for spontaneous non-neurovascular acute bleeding in patients
with coagulopathy. Materials and Methods: This study is a multicenter analysis of retrospectively
collected data of consecutive patients with coagulopathy who had undergone, from January 2018
to May 2023, transcatheter arterial embolization for the management of spontaneous hemorrhages.
Results: During the study interval (January 2018âMay 2023), 120 patients with coagulopathy underwent
TAE for spontaneous non-neurovascular acute bleeding. The abdominal wall was the most
common bleeding site (72.5%). The most commonly used embolic agent was polyvinyl alcohol (PVA)
particles or microspheres (25.0%), whereas coils and gelatin sponge together accounted for 32.5% of
the embolic agents used. Technical success was achieved in all cases, with a 92.5% clinical success rate
related to 9 cases of rebleeding. Complications were recorded in 12 (10%) patients. Clinical success
was significantly better in the group of patients who underwent correction of the coagulopathy within 24 h of TAE. Conclusions: Transcatheter arterial embolization (TAE) is effective and safe for
the management of acute non-neurovascular bleeding in patients with coagulopathy. Correction of
coagulopathy should not delay TAE and vice versa, as better clinical outcomes were noted in the
subgroup of patients undergoing correction of coagulopathy within 24 h of TAE
Men and wolves: Anthropogenic causes are an important driver of wolf mortality in human-dominated landscapes in Italy
Over the last 40 years the gray wolf (Canis lupus) re-colonized its historical range in Italy increasing human-predator interactions. However, temporal and spatial trends in wolf mortality, including direct and indirect persecution, were never summarized. This study aims to fill this gap by focusing on the situation of Tuscany and Emilia-Romagna regions, hosting a significant proportion of the Italian wolf population, by: (i) identifying the prevalent causes of wolf mortality, (ii) summarizing their temporal and spatial patterns and (iii) applying spatially-explicit Generalized Linear Models to predict wolf persecution. Between October 2005 and February 2021, 212 wolf carcasses were collected and subjected to necropsy, being involved in collisions with vehicles (n = 104), poisoned (n = 45), wounded with gunshot (n = 24) or blunt objects (n = 4) and being hanged (n = 2). The proportion of illegally killed wolves did not increase through time. Most persecution events occurred between October and February. None of our candidate models outperformed a null model and covariates such as the density of sheep farms, number of predations on livestock, or human density were never associated to the probability of having illegally killed wolves, at the municipal scale. Our findings show that conventional correlates of wolf persecution, combined with a supposedly high proportion of non-retrieved carcasses, fail to predict illegal wolf killings in areas where the species have become ubiquitous. The widespread spatial distribution of illegal killings indicates that persecution probably arises from multiple kinds of conflicts with humans, beyond those with husbandry. Wolf conservation in Italy should thus address cryptic wolf killings with multi-disciplinary approaches, such as shared national protocols, socioecological studies, the support of expertsâ experience and effective sampling schemes for the detection of carcasses
Repressing Anarchy in Neutrino Mass Textures
The recent results that is relatively large, of the order of
the previous upper bound, and the indications of a sizable deviation of
from the maximal value are in agreement with the predictions of
Anarchy in the lepton sector. The quark and charged lepton hierarchies can then
be reproduced in a SU(5) GUT context by attributing non-vanishing
charges, different for each family, only to the SU(5) tenplet states. The fact
that the observed mass hierarchies are stronger for up quarks than for down
quarks and charged leptons supports this idea. As discussed in the past, in the
flexible context of , different patterns of charges can
be adopted going from Anarchy to various types of hierarchy. We revisit this
approach by also considering new models and we compare all versions to the
present data. As a result we confirm that, by relaxing the extreme ansatz of
equal charges for all SU(5) pentaplets and singlets, better
agreement with the data than for Anarchy is obtained without increasing the
model complexity. We also present the distributions obtained in the different
models for the Dirac CP-violating phase. Finally we discuss the relative merits
of these simple models.Comment: v1: 12 pages, 3 figures; v2: 13 pages, 3 figures, text improved,
matches version accepted for publication; v3: submitted to add an
acknowledgment to a networ
The rapid spread of SARS-COV-2 Omicron variant in Italy reflected early through wastewater surveillance
The SARS-CoV-2 Omicron variant emerged in South Africa in November 2021, and has later been identified worldwide,
raising serious concerns.
A real-time RT-PCR assay was designed for the rapid screening of the Omicron variant, targeting characteristic mutations
of the spike gene. The assay was used to test 737 sewage samples collected throughout Italy (19/21 Regions) between
11 November and 25 December 2021, with the aim of assessing the spread of the Omicron variant in the
country. Positive samples were also tested with a real-time RT-PCR developed by the European Commission, Joint
Research Centre (JRC), and through nested RT-PCR followed by Sanger sequencing.
Overall, 115 samples tested positive for Omicron SARS-CoV-2 variant. The first occurrence was detected on 7
December, in Veneto, North Italy. Later on, the variant spread extremely fast in three weeks, with prevalence of positive
wastewater samples rising from 1.0% (1/104 samples) in the week 5â11 December, to 17.5% (25/143 samples)
in the week 12â18, to 65.9% (89/135 samples) in the week 19â25, in line with the increase in cases of infection with
the Omicron variant observed during December in Italy. Similarly, the number of Regions/Autonomous Provinces in
which the variant was detected increased fromone in the first week, to 11 in the second, and to 17 in the last one. The
presence of the Omicron variant was confirmed by the JRC real-time RT-PCR in 79.1% (91/115) of the positive samples,
and by Sanger sequencing in 66% (64/97) of PCR amplicons
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