438 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
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
Enhancement of Bacillus thuringiensis toxicity by feeding Spodoptera littoralis larvae with bacteria expressing immune suppressive dsRNA
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Evidence for Avian Intrathoracic Air Sacs in a New Predatory Dinosaur from Argentina
Background: Living birds possess a unique heterogeneous pulmonary system composed of a rigid, dorsally-anchored lung and several compliant air sacs that operate as bellows, driving inspired air through the lung. Evidence from the fossil record for the origin and evolution of this system is extremely limited, because lungs do not fossilize and because the bellow-like air sacs in living birds only rarely penetrate (pneumatize) skeletal bone and thus leave a record of their presence.Methodology/Principal Findings: We describe a new predatory dinosaur from Upper Cretaceous rocks in Argentina, Aerosteon riocoloradensis gen. et sp. nov., that exhibits extreme pneumatization of skeletal bone, including pneumatic hollowing of the furcula and ilium. In living birds, these two bones are pneumatized by diverticulae of air sacs (clavicular, abdominal) that are involved in pulmonary ventilation. We also describe several pneumatized gastralia (“stomach ribs”), which suggest that diverticulae of the air sac system were present in surface tissues of the thorax.Conclusions/Significance: We present a four-phase model for the evolution of avian air sacs and costosternal-driven lung ventilation based on the known fossil record of theropod dinosaurs and osteological correlates in extant birds:(1) Phase I—Elaboration of paraxial cervical air sacs in basal theropods no later than the earliest Late Triassic.(2) Phase II—Differentiation of avian ventilatory air sacs, including both cranial (clavicular air sac) and caudal (abdominal air sac) divisions, in basal tetanurans during the Jurassic. A heterogeneous respiratory tract with compliant air sacs, in turn, suggests the presence of rigid, dorsally attached lungs with flow-through ventilation.(3) Phase III—Evolution of a primitive costosternal pump in maniraptoriform theropods before the close of the Jurassic.(4) Phase IV—Evolution of an advanced costosternal pump in maniraptoran theropods before the close of the Jurassic.In addition, we conclude:(5) The advent of avian unidirectional lung ventilation is not possible to pinpoint, as osteological correlates have yet to be identified for uni- or bidirectional lung ventilation.(6) The origin and evolution of avian air sacs may have been driven by one or more of the following three factors: flow-through lung ventilation, locomotory balance, and/or thermal regulation.</p
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
A modular approach for remote operation of humanoid robots in search and rescue scenarios
In the present work we have designed and implemented a modular, robust and user-friendly Pilot Interface
meant to control humanoid robots in rescue scenarios during dangerous missions. We follow the common
approach where the robot is semi-autonomous and it is remotely controlled by a human operator. In our
implementation, YARP is used both as a communication channel for low-level hardware components and as an
interconnecting framework between control modules. The interface features the capability to receive the status
of these modules continuously and request actions when required. In addition, ROS is used to retrieve data
from different types of sensors and to display relevant information of the robot status such as joint positions,
velocities and torques, force/torque measurements and inertial data. Furthermore the operator is immersed into
a 3D reconstruction of the environment and is enabled to manipulate 3D virtual objects. The Pilot Interface
allows the operator to control the robot at three different levels. The high-level control deals with human-like
actions which involve the whole robot’s actuation and perception. For instance, we successfully teleoperated
IIT’s COmpliant huMANoid (COMAN) platform to execute complex navigation tasks through the composition
of elementary walking commands (e.g.[walk_forward, 1m]). The mid-level control generates tasks in cartesian
space, based on the position and orientation of objects of interest (i.e. valve, door handle) w.r.t. a reference
frame on the robot. The low level control operates in joint space and is meant as a last resort tool to perform fine
adjustments (e.g. release a trapped limb). Finally, our Pilot Interface is adaptable to different tasks, strategies
and pilot’s needs, thanks to a modular architecture of the system which enables to add/remove single front-end
components (e.g. GUI widgets) as well as back-end control modules on the fly
Maximizing Nash Social Welfare in 2-Value Instances: The Half-Integer Case
We consider the problem of maximizing the Nash social welfare when allocatinga set of indivisible goods to a set of agents. We study instances, inwhich all agents have 2-value additive valuations: The value of a good g \inG for an agent is either or , where is an odd multiple of larger than one. We show that the problem is solvable inpolynomial time. Akrami et at. showed that this problem is solvable inpolynomial time if is integral and is NP-hard whenever , and are co-prime and . Forthe latter situation, an approximation algorithm was also given. It obtains anapproximation ratio of at most . Moreover, the problem is APX-hard,with a lower bound of achieved at . Thecase and odd was left open. In the case of integral , the problem is separable in the sense that theoptimal allocation of the heavy goods (= value for some agent) isindependent of the number of light goods (= value for all agents). Thisleads to an algorithm that first computes an optimal allocation of the heavygoods and then adds the light goods greedily. This separation no longer holdsfor ; a simple example is given in the introduction. Thus analgorithm has to consider heavy and light goods together. This complicatesmatters considerably. Our algorithm is based on a collection of improvementrules that transfers any allocation into an optimal allocation and exploits aconnection to matchings with parity constraints.<br
Maximizing Nash Social Welfare in 2-Value Instances
We consider the problem of maximizing the Nash social welfare when allocatinga set of indivisible goods to a set of agents. Westudy instances, in which all agents have 2-value additive valuations: Thevalue of every agent for every good is, for , . Maybe surprisingly,we design an algorithm to compute an optimal allocation in polynomial time if divides , i.e., when and after appropriatescaling. The problem is \classNP-hard whenever and are coprime and . In terms of approximation, we present positive and negative results forgeneral and . We show that our algorithm obtains an approximation ratioof at most 1.0345. Moreover, we prove that the problem is \classAPX-hard, witha lower bound of achieved at .<br
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