766 research outputs found
Influence of burnout and sleep difficulties on the quality of life among medical students
This study assessed the influence of burnout dimensions and sleep difficulties on the quality of life among preclinical-phase medical school students. Data were collected from 193 students through their completion of the World Health Organization Quality of Life Instrument, the Maslach Burnout Inventory—Student Survey, the Mini-Sleep Questionnaire, the Social Readjustment Rating Scale, and the Beck Depression Inventory. This survey performed hierarchical multiple regressions to quantify the effects of emotional exhaustion, cynicism, academic efficacy, and sleep difficulties on the physical, psychological, social, and environmental components of an individual’s quality of life. The influence of confounding variables, such as gender, stress load, and depressive symptoms, were controlled in the statistical analyses. Physical health decreased when emotional exhaustion and sleep difficulties increased. Psychological well-being also decreased when cynicism and sleep difficulties increased. Burnout and sleep difficulties together explained 22 and 21 % of the variance in the physical and psychological well-being, respectively. On the other hand, physical health, psychological well-being, and social relationships increased when the sense of academic efficacy increased. Physical and psychological well-being are negatively associated with emotional exhaustion, cynicism, and sleep difficulties in students in the early phase of medical school. To improve the quality of life of these students, a significant effort should be directed towards burnout and sleep difficulties
Authentication under Constraints
Authentication has become a critical step to gain access to services such as on-line banking, e-commerce, transport systems and cars (contact-less keys). In several cases, however, the authentication process has to be performed under challenging conditions. This thesis is essentially a compendium of five papers which are the result of a two-year study on authentication in constrained settings. The two major constraints considered in this work are: (1) the noise and (2) the computational power. For what concerns authentication under noisy conditions, Paper A and Paper B ad- dress the case in which the noise is in the authentication credentials. More precisely, the aforementioned papers present attacks against biometric authentication systems, that exploit the inherent variant nature of biometric traits to gain information that should not be leaked by the system. Paper C and Paper D study proximity- based authentication, i.e., distance-bounding protocols. In this case, both of the constraints are present: the possible presence of noise in the channel (which affects communication and thus the authentication process), as well as resource constraints on the computational power and the storage space of the authenticating party (called the prover, e.g., an RFID tag). Finally, Paper E investigates how to achieve reliable verification of the authenticity of a digital signature, when the verifying party has limited computational power, and thus offloads part of the computations to an untrusted server. Throughout the presented research work, a special emphasis is given to privacy concerns risen by the constrained conditions
Relationship between NOX4 level and angiotensin II signaling in Gitelman's syndrome. Implications with hypertension
Recent evidence showed that endogenous nicotinamide adenine dinucleotide phosphate-oxidase 4 (NOX4) may exert a protective role on the cardiovascular system inducing vasodilation, reduction of blood pressure, and anti-proliferative actions. However, the functional significance of NOX4 in the cardiovascular system in humans remains elusive. Mononuclear cell levels of NOX4 were assessed by immunoblotting in 14 Gitelman's patients (GS), a unique human model of endogenous Ang II signaling antagonism and activation of anti-atherosclerotic and anti-remodeling defenses, and compared to 11 untreated essential hypertensive patients as well as to 11 healthy normotensive subjects. The association between NOX4 and its effector heme oxygenase (HO-1) (sandwich immunoassay) was also evaluated. NOX4 protein levels were decreased in hypertensive patients as compared to both GS and healthy subjects (1.06±0.31 AU vs. 1.76±0.54, P=0.002 and vs. 1.61±0.54, P=0.018, respectively). NOX4 protein level did not differ between GS and healthy subjects. HO-1 levels were increased in GS patients as compared to both hypertensive patients and healthy subjects (8.65±3.08 ng/ml vs 3.70±1.19, P<0.0001, and vs 5.49±1.04, P=0.008, respectively. NOX4 levels correlate with HO-1 levels only in GS (r(2)=0.63; P=0.001), (r(2)=0.088; P=ns, in hypertensive patients and r(2)=0.082; P=ns, in healthy subjects). Our findings show that NOX4 and its effector HO-1 are reduced in hypertensive patients compared to GS patients, a human model opposite to hypertension. Although the functional significance of NOX4 needs further clarification, our preliminary data in a unique human model of anti-atherosclerotic and anti-remodeling defenses activation, highlight the potentially protective role of NOX4 in the human cardiovascular system
Theory of mind and school achievement: the mediating role of social competence
Recent findings have highlighted the importance of children's social understanding – specifically their reasoning about beliefs and emotions – for school achievement. However, little is known about the processes that may account for such a relationship. In this longitudinal study we examined the role of children's social competence (as indexed by peer relationships and social skills), using a multi-informant and multi-indicator approach. We followed 73 children during the transition to primary school, gathering data at three time points: Time 1 (age 5), Time 2 (age 7) and Time 3 (age 8). Structural equation modelling showed that Time 1 social understanding predicted Time 2 social competence, which in turn predicted Time 3 school achievement, independently of verbal ability. Moreover, social competence mediated the relationship between early social understanding and later school achievement. Theoretical and practical implications of these findings are discussed
Endothelin-1 Drives Epithelial-Mesenchymal Transition In Hypertensive Nephroangiosclerosis
BACKGROUND: Tubulointerstitial fibrosis, the final outcome of most kidney diseases, involves activation of epithelial mesenchymal transition (EMT). Endothelin‐1 (ET‐1) activates EMT in cancer cells, but it is not known whether it drives EMT in the kidney. We therefore tested the hypothesis that tubulointerstitial fibrosis involves EMT driven by ET‐1. METHODS AND RESULTS: Transgenic TG[mRen2]27 (TGRen2) rats developing fulminant angiotensin II–dependent hypertension with prominent cardiovascular and renal damage were submitted to drug treatments targeted to ET‐1 and/or angiotensin II receptor or left untreated (controls). Expressional changes of E‐cadherin and α‐smooth muscle actin (αSMA) were examined as markers of renal EMT. In human kidney HK‐2 proximal tubular cells expressing the ET(B) receptor subtype, the effects of ET‐1 with or without ET‐1 antagonists were also investigated. The occurrence of renal fibrosis was associated with EMT in control TGRen2 rats, as evidenced by decreased E‐cadherin and increased αSMA expression. Irbesartan and the mixed ET‐1 receptor antagonist bosentan prevented these changes in a blood pressure–independent fashion (P < 0.001 for both versus controls). In HK‐2 cells ET‐1 blunted E‐cadherin expression, increased αSMA expression (both P < 0.01), collagen synthesis, and metalloproteinase activity (P < 0.005, all versus untreated cells). All changes were prevented by the selective ET(B) receptor antagonist BQ‐788. Evidence for involvement of the Rho‐kinase signaling pathway and dephosphorylation of Yes‐associated protein in EMT was also found. CONCLUSIONS: In angiotensin II–dependent hypertension, ET‐1 acting via ET(B) receptors and the Rho‐kinase and Yes‐associated protein induces EMT and thereby renal fibrosis
STAT3 mutation impacts biological and clinical features of T-LGL leukemia
STAT3 mutations have been described in 30-40% of T-large granular lymphocyte (T-LGL) leukemia patients, leading to STAT3 pathway activation. Considering the heterogeneity of the disease and the several immunophenotypes that LGL clone may express, the aim of this work was to evaluate whether STAT3 mutations might be associated with a distinctive LGL immunophenotype and/or might be indicative for specific clinical features.Our series of cases included a pilot cohort of 101 T-LGL leukemia patients (68 CD8+/CD4- and 33 CD4+/CD8\ub1) from Padua Hematology Unit (Italy) and a validation cohort of additional 20 patients from Rennes Hematology Unit (France).Our results indicate that i) CD8+ T-LGL leukemia patients with CD16+/CD56- immunophenotype identify a subset of patients characterized by the presence of STAT3 mutations and neutropenia, ii) CD4+/CD8\ub1 T-LGL leukemia are devoid of STAT3 mutations but characterized by STAT5b mutations, and iii) a correlation exists between STAT3 activation and presence of Fas ligand, this molecule resulting highly expressed in CD8+/CD16+/CD56- patients. Experiments with stimulation and inhibition of STAT3 phosphorylation confirmed this relationship. In conclusion, our data show that T-LGL leukemia with specific molecular and phenotypic patterns is associated with discrete clinical features contributing to get insights into molecular bases accounting for the development of Fas ligand-mediated neutropenia
Decarbonizing the cold chain: Long-haul refrigerated deliveries with on-board photovoltaic energy integration
Decarbonizing the cold chain is a priority for sustainability due to the increasing demand for chilled/frozen food and pharmaceutics. Refrigerated transport requires additional fuel for refrigeration other than for traction. Photovoltaic panels on the vehicle rooftop, a battery bank, and a power conversion system can replace the diesel engine driving the transport refrigerated unit. In long-haul deliveries, vehicles cross zones with different climate conditions, which affect both refrigeration requirements and photovoltaic energy conversion. Mandatory driver\u2019s breaks and rest also affect delivery timing and energy consumption. A multiperiod, multizone optimization model is developed to size the onboard photovoltaic system, based on features of the delivery tour. The model is applied to a palletized chilled food delivery from North-Eastern Italy, showing a payback time of around four years, which can drop under two years for expected reduction of component costs. Economic and environmental performances can be increased by also allowing refrigerated products on-board during the return journey, leading to more fuel savings. Photovoltaic-integrated long-haul delivery for frozen products is not convenient at current market costs. Different climate conditions are tested, showing the model ability to act as a decision support tool to foster renewable energy penetration into the cold chain
Metadata Privacy Beyond Tunneling for Instant Messaging
Transport layer data leaks metadata unintentionally -- such as who
communicates with whom. While tools for strong transport layer privacy exist,
they have adoption obstacles, including performance overheads incompatible with
mobile devices. We posit that by changing the objective of metadata privacy for
, we can open up a new design space for pragmatic
approaches to transport layer privacy. As a first step in this direction, we
propose using techniques from information flow control and present a principled
approach to constructing formal models of systems with metadata privacy for
, deniable, traffic. We prove that deniable traffic achieves
metadata privacy against strong adversaries -- this constitutes the first
bridging of information flow control and anonymous communication to our
knowledge. Additionally, we show that existing state-of-the-art protocols can
be extended to support metadata privacy, by designing a novel protocol for
(DenIM), which is a variant of the Signal
protocol. To show the efficacy of our approach, we implement and evaluate a
proof-of-concept instant messaging system running DenIM on top of unmodified
Signal. We empirically show that the DenIM on Signal can maintain low-latency
for unmodified Signal traffic without breaking existing features, while at the
same time supporting deniable Signal traffic.Comment: To appear at the 9th IEEE European Symposium on Security and Privac
How Can Ozone and Relative Humidity Affect Artists’ Alkyd Paints? A FT-IR and Py-GC/MS Systematic Study
Knowledge of the chemical–physical reactions that determine the main degradation behaviour of artists’ alkyd paints represents one of the main problems within the museum exhibitions. The collection and interpretation of these data on degradation phenomena, especially after ozone exposure at different relative humidity values, can be useful for their conservation needs. Therefore, a systematic investigation of these materials may help achieve this goal. Firstly, surface-level identification of the main functional groups of ad hoc created and aged alkyd paints was performed using attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR). Subsequently, these paints were investigated by pyrolysis–gas chromatography and mass spectrometry (Py–GC/MS), allowing for precise bulk identification of the organic compounds before and after accelerated ageing. A first successful attempt to provide quantitative Py–GC/MS data on alkyd-based paints is here presented and discussed. Comparing the results, it was possible to obtain new insights into the degradation behaviour of alkyd paints when exposed to ozone, allowing us to devise specific preventive and conservation strategies for these artistic materials
Be More and be Merry: Enhancing Data and User Authentication in Collaborative Settings
Cryptography is the science and art of keeping information secret to un-intended parties. But, how can we determine who is an intended party and who is not? Authentication is the branch of cryptography that aims at confirming the source of data or at proving the identity of a person. This Ph.D. thesis is a study of different ways to perform cryptographic authentication of data and users. The main contributions are contained in the six papers included in this thesis and cover the following research areas: (i) homomorphic authentication; (ii) server-aided verification of signatures; (iii) distance-bounding authentication; and (iv) biometric authentication. The investigation flow is towards collaborative settings, that is, application scenarios where different and mutually distrustful entities work jointly for a common goal. The results presented in this thesis allow for secure and efficient authentication when more entities are involved, thus the title “be more and be merry”. Concretely, the first two papers in the collection are on homomorphic authenticators and provide an in-depth study on how to enhance existing primitives with multi- key functionalities. In particular, the papers extend homomorphic signatures and homomorphic message authentication codes to support computations on data authenticated using different secret keys. The third paper explores signer anonymity in the area of server-aided verification and provides new secure constructions. The fourth paper is in the area of distance-bounding authentication and describes a generic method to make existing protocols not only authenticate direct-neighbors, but also entities located two-hop away. The last two papers investigate the leakage of information that affects a special family of biometric authentication systems and how to combine verifiable computation techniques with biometric authentication in order to mitigate known attacks
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