On the Salecker-Wigner-Peres clock and double barrier tunneling

In this work we revisit the Salecker-Wigner-Peres clock formalism and show that it can be directly applied to the phenomenon of tunneling. Then we apply this formalism to the determination of the tunneling time of a non relativistic wavepacket, sharply concentrated around a tunneling energy, incident on a symmetric double barrier potential. In order to deepen the discussion about the generalized Hartmann effect, we consider the case in which the clock runs only when the particle can be found inside the region \emph{between} the barriers and show that, whenever the probability to find the particle in this region is non negligible, the corresponding time (which in this case turns out to be a dwell time) increases with the barrier spacing.Comment: To appear in Phys. Rev.

Torsion and the Gravitational Interaction

By using a nonholonomous-frame formulation of the general covariance principle, seen as an active version of the strong equivalence principle, an analysis of the gravitational coupling prescription in the presence of curvature and torsion is made. The coupling prescription implied by this principle is found to be always equivalent with that of general relativity, a result that reinforces the completeness of this theory, as well as the teleparallel point of view according to which torsion does not represent additional degrees of freedom for gravity, but simply an alternative way of representing the gravitational field.Comment: Version 2: minor presentation changes, a reference added, 11 pages (IOP style

Cerebral malaria model applying human brain organoids

Neural injuries in cerebral malaria patients are a significant cause of morbidity and mortality. Nevertheless, a comprehensive research approach to study this issue is lacking, so herein we propose an in vitro system to study human cerebral malaria using cellular approaches. Our first goal was to establish a cellular system to identify the molecular alterations in human brain vasculature cells that resemble the blood–brain barrier (BBB) in cerebral malaria (CM). Through transcriptomic analysis, we characterized specific gene expression profiles in human brain microvascular endothelial cells (HBMEC) activated by the Plasmodium falciparum parasites. We also suggest potential new genes related to parasitic activation. Then, we studied its impact at brain level after Plasmodium falciparum endothelial activation to gain a deeper understanding of the physiological mechanisms underlying CM. For that, the impact of HBMEC-P. falciparum-activated secretomes was evaluated in human brain organoids. Our results support the reliability of in vitro cellular models developed to mimic CM in several aspects. These systems can be of extreme importance to investigate the factors (parasitological and host) influencing CM, contributing to a molecular understanding of pathogenesis, brain injury, and dysfunction.This research was funded by National funds through the Foundation for Science and Technology (FCT) SFRH/BD/131540/2017, SFRH/BD/5813/2020, COVID/BD/152416/2022 and UMINHO/BIM-CNCG/2022/143. This work has been funded by ICVS Scientific Microscopy Platform, member of the national infrastructure PPBI - Portuguese Platform of Bioimaging (PPBIPOCI-01-0145-FEDER-022122; by National funds, through the FCT—project UIDB/50026/2020 and UIDP/50026/2020. Moreover, this work was funded by IF/00143/2015/CP1294/CT0001, PTDC/SAU-PAR/2766/2021 and UIDB/04469/2020. O.M. is funded by the project NORTE-01- 0247-FEDER-045914, supported by POFC–COMPETE and FCT, under the programs PT2020 and NORTE2020. M.I.V. thanks FCT for her contract funding provided through 2020.03113.CEECIND.info:eu-repo/semantics/publishedVersio

Experimental evaluation of the usage of ad hoc networks as stubs for multiservice networks

This paper describes an experimental evaluation of a multiservice ad hoc network, aimed to be interconnected with an infrastructure, operator-managed network. This network supports the efficient delivery of services, unicast and multicast, legacy and multimedia, to users connected in the ad hoc network. It contains the following functionalities: routing and delivery of unicast and multicast services; distributed QoS mechanisms to support service differentiation and resource control responsive to node mobility; security, charging, and rewarding mechanisms to ensure the correct behaviour of the users in the ad hoc network. This paper experimentally evaluates the performance of multiple mechanisms, and the influence and performance penalty introduced in the network, with the incremental inclusion of new functionalities. The performance results obtained in the different real scenarios may question the real usage of ad-hoc networks for more than a minimal number of hops with such a large number of functionalities deployed

Nursing Actions in practicing inpatient advocacy in a Burn Unit

OBJECTIVEUnderstanding nursing actions in the practice of inpatient advocacy in a burn unit.METHODA single and descriptive case study, carried out with nurses working in a referral burn center in southern Brazil. Data were collected through focus group technique, between February and March 2014, in three meetings. Data was analysed through discursive textual analysis.RESULTSThree emerging categories were identified, namely: (1) instructing the patient; (2) protecting the patient; and (3) ensuring the quality of care.CONCLUSIONSThis study identified that the nurses investigated exercised patient advocacy and that the recognition of their actions is an advance for the profession, contributing to the autonomy of nurses and the effectiveness of patients' rights and social justice

The impact of human expert visual inspection on the discovery of strong gravitational lenses

We investigate the ability of human ’expert’ classifiers to identify strong gravitational lens candidates in Dark Energy Survey like imaging. We recruited a total of 55 people that completed more than 25% of the project. During the classification task, we present to the participants 1489 images. The sample contains a variety of data including lens simulations, real lenses, non-lens examples, and unlabeled data. We find that experts are extremely good at finding bright, well-resolved Einstein rings, whilst arcs with g-band signal-to-noise less than ∼25 or Einstein radii less than ∼1.2 times the seeing are rarely recovered. Very few non-lenses are scored highly. There is substantial variation in the performance of individual classifiers, but they do not appear to depend on the classifier’s experience, confidence or academic position. These variations can be mitigated with a team of 6 or more independent classifiers. Our results give confidence that humans are a reliable pruning step for lens candidates, providing pure and quantifiably complete samples for follow-up studies