675 research outputs found
Bond-slip analysis via a cohesive-zone model simulating damage, friction and interlocking
A recently proposed cohesive-zone model which effectively combines damage, friction and mechanical interlocking has been revisited and further validated by numerically simulating the pull-out test, from a concrete block, of a ribbed steel bar in the post-yield deformation range. The simulated response is in good agreement with experimental measurements of the bond slip characteristics in the post-yield range of deformed bars reported in the literature. This study highlights the main features of the model: with physically justified and relatively simple arguments, and within the sound framework of thermodynamics with internal variables, the model effectively separates the three main sources of energy dissipation, i.e. loss of adhesion, friction along flat interfaces and mechanical interlocking. This study provides further evidence that the proposed approach allows easier and physically clearer procedures for the determination of the model parameters of such three elementary mechanical behaviours, and makes possible their interpretation and measurement as separate material property, as a viable alternative to lumping these parameters into single values of the fracture energy. In particular, the proposed approach allows to consider a single value of the adhesion energy for modes I and II
Skeletal myocyte types and vascularity in the Black Sicilian Pig.
The objective of this study was to verify the presence of giant fibres in the Black Sicilian pig skeletal
muscle and to evaluate the effect of sex on histochemical and morphometric characteristics of the
myocytes (myofibres) as well as vascularity of the muscle. Twenty Black Sicilian pigs (10 males, 10
females) from a farm in Sicily (Italy) were slaughtered at two years of age. Muscle tissues were
obtained from three muscles: psoas major, longissimus dorsi, and trapezius. Myofibres were stained
for myosin ATPase, succinic dehydrogenase, and α-amylase-PAS. For all fibre types, area and
perimeter were measured. Slow-twitch oxidative fibres, fast-twitch glycolytic fibres and fast-twitch
oxidative-glycolytic fibres were histochemically differentiated; an image-analyzing system was
used. The results showed no differences between males and females in percentage of the fibre types,
but there were significant differences between sexes in size of all the three fibre types. Psoas major
muscle had a high percentage of slow-twitch oxidative fibres and contained more capillaries per fibre
and per mm2 than trapezius and longissimus dorsi, in which fast-twitch glycolytic fibres dominated.
The cross-sectional area of all fibres types was larger in longissimus dorsi than in trapezius and psoas
major muscles; the giant fibres were absent in all the muscles studied. Fibre type composition may
contribute to the variation of meat quality
Post-natal parental care in a Cretaceous diapsid from northeastern China
Post-natal parental care seems to have evolved numerous times in vertebrates. Among extant amniotes, it is present in crocodilians, birds, and mammals. However, evidence of this behavior is extremely rare in the fossil record and is only reported for two types of dinosaurs, and a varanopid ‘pelycosaur’. Here we report new evidence for post-natal parental care in Philydrosaurus, a choristodere, from the Yixian Formation of western Liaoning Province, China. We review the fossil record of reproduction in choristoderes, and this represents the oldest record of post-natal parental care in diapsids to our knowledge
Prostitution, Essential and Incidental Aspects: A Liberal Argument for Legalization
Prostituciju se često prikazuje agresivnom i prisilnom aktivnosti, pri čemu imamo uvjerljive empirijske dokaze da ponekad i jest tako. Međutim, to nije dovoljno da bi bila nezakonita. Naš je argument da bi aktivnost trebala postati nezakonita ako i samo ako je u svojoj suštini agresivna i/ili prisilna. No, prostitucija sama po sebi nije nasilna, samo incidentno. Zaista, prostitucija se može definirati kao čin pružanja, iz perspektive mušterije, ne-reproduktivnog spolnog odnosa za novac (Edlund and Korn, 2002). Ni agresija ni prisila nužno ne ulaze u ovu sveobuhvatnu definiciju. Zbog toga prostituciju treba legalizirati, a zakone koji je zabranjuju ukinuti.Prostitution is often depicted as an aggressive and coercive activity. We have convincing empirical evidence that sometimes this is indeed the case. However, this is not sufficient to make it illegal. We argue that an activity should be outlawed if and only if it is essentially aggressive and/or coercive. But prostitution is not inherently violent, only incidentally. Indeed, prostitution could be defined as “the act of rendering, from the client’s point of view, non-reproductive sex against
payment” (Edlund and Korn, 2002). No aggression and/or coercion necessarily enters this all-inclusive definition. This is why prostitution should be legalized laws to the contrary repealed
Autoimmune mucocutaneous blistering diseases after SARS-Cov-2 vaccination: A Case report of Pemphigus Vulgaris and a literature review
Background: Cases of severe autoimmune blistering diseases (AIBDs) have recently been reported in association with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination. Aims: To describe a report of oropharyngeal Pemphigus Vulgaris (OPV) triggered by the mRNABNT162b2 vaccine (Comirnaty®/ Pfizer/ BioNTech) and to analyze the clinical and immunological characteristics of the AIBDs cases reported following the SARS-CoV-2 vaccination. Methods: The clinical and immunological features of our case of OPV were documented. A review of the literature was conducted and only cases of AIBDs arising after the SARS-CoV-2 vaccination were included. Case report: A 60-year old female patients developed oropharyngeal and nasal bullous lesions seven days after the administration of a second dose of the mRNABNT162b2 vaccine (Comirnaty®/ Pfizer/BioNtech). According to the histology and direct immunofluorescence findings showing the presence of supra-basal blister and intercellular staining of IgG antibodies and the presence of a high level of anti-Dsg-3 antibodies (80 U/ml; normal < 7 U/ml) in the serum of the patients, a diagnosis of oropharyngeal Pemphigus Vulgaris was made. Review: A total of 35 AIBDs cases triggered by the SARS-CoV-2 vaccination were found (including our report). 26 (74.3%) were diagnosed as Bullous Pemphigoid, 2 (5.7%) as Linear IgA Bullous Dermatosis, 6 (17.1%) as Pemphigus Vulgaris and 1 (2.9%) as Pemphigus Foliaceus. The mean age of the sample was 72.8 years and there was a predominance of males over females (F:M=1:1.7). In 22 (62.9%) cases, the disease developed after Pfizer vaccine administration, 6 (17.1%) after Moderna, 3 (8.6%) after AstraZeneca, 3 (8.6%) after CoronaVac (one was not specified). All patients were treated with topical and/or systemic corticosteroids, with or without the addition of immunosuppressive drugs, with a good clinical response in every case. Conclusion: Clinicians should be aware of the potential, though rare, occurrence of AIBDs as a possible adverse event after the SARS-CoV-2 vaccination. However, notwithstanding, they should encourage their patients to obtain the vaccination in order to assist the public health systems to overcome the COVID-19 pandemic
A new large-bodied oviraptorosaurian theropod dinosaur from the Latest Cretaceous of Western North America
The oviraptorosaurian theropod dinosaur clade Caenagnathidae has long been enigmatic due to the incomplete nature of nearly all described fossils. Here we describe Anzu wyliei gen. et sp. nov., a new taxon of large-bodied caenagnathid based primarily on three well-preserved partial skeletons. The specimens were recovered from the uppermost Cretaceous (upper Maastrichtian) Hell Creek Formation of North and South Dakota, and are therefore among the stratigraphically youngest known oviraptorosaurian remains. Collectively, the fossils include elements from most regions of the skeleton, providing a wealth of information on the osteology and evolutionary relationships of Caenagnathidae. Phylogenetic analysis reaffirms caenagnathid monophyly, and indicates that Anzu is most closely related to Caenagnathus collinsi, a taxon that is definitively known only from a mandible from the Campanian Dinosaur Park Formation of Alberta. The problematic oviraptorosaurs Microvenator and Gigantoraptor are recovered as basal caenagnathids, as has previously been suggested. Anzu and other caenagnathids may have favored well-watered floodplain settings over channel margins, and were probably ecological generalists that fed upon vegetation, small animals, and perhaps eggs
Genome-wide DNA methylation levels and altered cortisol stress reactivity following childhood trauma in humans
DNA methylation likely plays a role in the regulation of human stress reactivity. Here we show that in a genome-wide analysis of blood DNA methylation in 85 healthy individuals, a locus in the Kit ligand gene (KITLG; cg27512205) showed the strongest association with cortisol stress reactivity (P=5.8 � 10?6). Replication was obtained in two independent samples using either blood (N=45, P=0.001) or buccal cells (N=255, P=0.004). KITLG methylation strongly mediates the relationship between childhood trauma and cortisol stress reactivity in the discovery sample (32% mediation). Its genomic location, a CpG island shore within an H3K27ac enhancer mark, and the correlation between methylation in the blood and prefrontal cortex provide further evidence that KITLG methylation is functionally relevant for the programming of stress reactivity in the human brain. Our results extend preclinical evidence for epigenetic regulation of stress reactivity to humans and provide leads to enhance our understanding of the neurobiological pathways underlying stress vulnerability
Lung ultrasound and BNP to detect hidden pulmonary congestion in euvolemic hemodialysis patients: a single centre experience
Background: Dry weight assessment in hemodialysis (HD) remains a challenge. The aim of the study was to investigate the prevalence of subclinical pulmonary congestion using lung ultrasound (LUS) in maintenance HD patients with no clinical or bioimpedance signs of hyperhydration. The correlation between B-lines Score (BLS) and brain natriuretic peptide (BNP) was also evaluated. Methods: Twenty-four HD patients underwent LUS and BNP dosage at the end of the mid-week HD session, monthly for 6 months. LUS was considered as positive when BLS was >15. Hospitalizations and cardiovascular events were also evaluated in relation to the BLS. Results: LUS+ patients at baseline were 16 (67%), whereas 11 (46%) showed LUS + in at least 50% of the measurements (rLUS+ patients). Only the rLUS+ patients had a higher number of cardiovascular events [p=0.019, OR: 7.4 (CI 95%. 1.32-39.8)] and hospitalizations [p=0.034, OR 5.5 (CI 95% 1.22- 24.89)]. A BNP level of 165 pg/ml was identified as cut-off value for predicting pulmonary congestion, defined by BLS >15. Conclusion: Prevalence of pulmonary congestion as assessed by LUS and persistent or recurrent BLS >15 were quite prevalent findings in euvolemic HD patients. In the patients defined as rLUS+, a higher rate of cardiovascular events and hospital admissions was registered. BNP serum levels > 165 pg/ml resulted predictive of pulmonary congestion at LUS. In the dialysis care, regular LUS examination should be reasonably included among the methods useful to detect subclinical lung congestion and to adjust patients’ dry weight
Maximizing {Nash} Social Welfare in 2-Value Instances: Delineating Tractability
We study the problem of allocating a set of indivisible goods among a set ofagents with \emph{2-value additive valuations}. In this setting, each good isvalued either or \sfrac{p}{q}, for some fixed co-prime numbers p,q\in\NN such that 1\leq q \emph{Nash social welfare} (\NSW), i.e., the geometric mean of the valuationsof the agents. In this work, we give a complete characterization ofpolynomial-time tractability of \NSW\ maximization that solely depends on thevalues of q. We start by providing a rather simple polynomial-time algorithm to find amaximum \NSW\ allocation when the valuation functions are \emph{integral}, thatis, q=1. We then exploit more involved techniques to get an algorithmproducing a maximum \NSW\ allocation for the \emph{half-integral} case, thatis, q=2. Finally, we show it is \classNP-hard to compute an allocation withmaximum \NSW\ whenever q\geq3$.<br
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