1,624 research outputs found
High-energy string-brane scattering: leading eikonal and beyond
We extend previous techniques for calculations of transplanckian-energy
string-string collisions to the high-energy scattering of massless closed
strings from a stack of N Dp-branes in Minkowski spacetime. We show that an
effective non-trivial metric emerges from the string scattering amplitudes by
comparing them against the semiclassical dynamics of high-energy strings in the
extremal p-brane background. By changing the energy, impact parameter and
effective open string coupling, we are able to explore various interesting
regimes and to reproduce classical expectations, including tidal-force
excitations, even beyond the leading-eikonal approximation.Comment: 40 pages, 5 figures, v2: minor corrections, new appendix with a
discussion of the Feynman diagrams contributing to the scattering amplitude
in the field theory limi
A combination of tryptophan, Satureja montana, Tribulus terrestris, Phyllanthus emblica extracts is able to improve sexual quality of life in patient with premature ejaculation
Objective: The management of patient affected by premature ejaculation (PE) is nowadays not highly satisfactory. Here, we aimed to evaluate the tolerability and efficacy of a combination of tryptophan, Satureja montana, Tribulus terrestris, Phyllanthus emblica extracts in order to improve sexual quality of life in patients with premature ejaculation. Materials and methods: All patients attending to 5 urological centers from January 2015 to March 2015, due to premature ejaculation were enrolled in this study. At the enrolment visit, all subjects underwent self-administered IIEF-5, Male Sexual Health Questionnaire-Ejaculation Disorder (MSHQ-EjD), PEDT and IELTS (calculated as mean from that perceived by partner and that perceived by patient) and underwent urological visit and laboratory examinations. All patients received one tablet per day of a combination of tryptophan, Satureja montana, Tribulus terrestris, Phyllanthus emblica extracts for 3 months (Group A). After 3 months all patients underwent follow-up visit with the same investigations that have been carried out in the enrolment visit. The results were compared with a cohort of patients enrolled in the same period in another urological center and considered as a control group (Group B). All patients in the control group underwent counseling and sexual behavioral treatment without any pharmacological compound. Results: At the follow-up analysis, significant changes in terms of IELT in the Group A (mean difference: 31.90; p < 0.05) at 3 months and versus Group B at the intergroup analysis (mean difference: 30.30; p < 0.05) were reported. In the group A, significant differences from baseline to last follow-up were observed relative to IIEF-5 (mean difference: 1.04; p < 0.05), PEDT (mean difference: -2.57; p < 0.05) and FSH (mean difference: -16.46; p < 0.05). Conclusion: In conclusion, patients affected by PE may significantly benefit from oral therapy with a combination of tryptophan, Satureja montana, Tribulus terrestris, Phyllanthus emblica extracts in terms of IELT and PEDT scores improvement
Automating the Generation of Cyber Range Virtual Scenarios with VSDL
A cyber range is an environment used for training security experts and
testing attack and defence tools and procedures. Usually, a cyber range
simulates one or more critical infrastructures that attacking (red) and
defending (blue) teams must compromise and protect, respectively. The
infrastructure can be physically assembled, but much more convenient is to rely
on the Infrastructure as a Service (IaaS) paradigm. Although some modern
technologies support the IaaS, the design and deployment of scenarios of
interest is mostly a manual operation. As a consequence, it is a common
practice to have a cyber range hosting few (sometimes only one), consolidated
scenarios. However, reusing the same scenario may significantly reduce the
effectiveness of the training and testing sessions. In this paper, we propose a
framework for automating the definition and deployment of arbitrarily complex
cyber range scenarios. The framework relies on the virtual scenario description
language (VSDL), i.e., a domain-specific language for defining high-level
features of the desired infrastructure while hiding low-level details. The
semantics of VSDL is given in terms of constraints that must be satisfied by
the virtual infrastructure. These constraints are then submitted to an SMT
solver for checking the satisfiability of the specification. If satisfiable,
the specification gives rise to a model that is automatically converted to a
set of deployment scripts to be submitted to the IaaS provider
Sirtuins 1–7 expression in human adipose-derived stem cells from subcutaneous and visceral fat depots: influence of obesity and hypoxia
The sirtuin family comprises seven NAD+-dependent deacetylases which control the overall health of organisms through the regulation of pleiotropic metabolic pathways. Sirtuins are important modulators of adipose tissue metabolism and their expression is higher in lean than obese subjects. At present, the role of sirtuins in adipose-derived stem cells has not been investigated yet. Therefore, in this study, we evaluated the expression of the complete panel of sirtuins in adipose-derived stem cells isolated from both subcutaneous and visceral fat of non-obese and obese subjects. We aimed at investigating the influence of obesity on sirtuins' levels, their role in obesity-associated inflammation, and the relationship with the peroxisome proliferator-activated receptor delta, which also plays functions in adipose tissue metabolism. The mRNA levels in the four types of adipose-derived stem cells were evaluated by quantitative polymerase chain reaction, in untreated cells and also after 8 h of hypoxia exposure. Correlations among sirtuins' expression and clinical and molecular parameters were also analyzed. We found that sirtuin1-6 exhibited significant higher mRNA expression in visceral adipose-derived stem cells compared to subcutaneous adipose-derived stem cells of non-obese subjects. Sirtuin1-6 levels were markedly reduced in visceral adipose-derived stem cells of obese patients. Sirtuins' expression in visceral adipose-derived stem cells correlated negatively with body mass index and C-reactive protein and positively with peroxisome proliferator-activated receptor delta. Finally, only in the visceral adipose-derived stem cells of obese patients hypoxia-induced mRNA expression of all of the sirtuins. Our results highlight that sirtuins' levels in adipose-derived stem cells are consistent with protective effects against visceral obesity and inflammation, and suggest a transcriptional mechanism through which acute hypoxia up-regulates sirtuins in the visceral adipose-derived stem cells of obese patients
QoS-aware offloading policies for serverless functions in the Cloud-to-Edge continuum
Function-as-a-Service (FaaS) paradigm is increasingly attractive to bring the benefits of serverless computing to the edge of the network, besides traditional Cloud data centers. However, FaaS adoption in the emerging Cloud-to-Edge Continuum is challenging, mostly due to geographical distribution and heterogeneous resource availability. This emerging landscape calls for effective strategies to trade off low latency at the edge of the network with Cloud resource richness, taking into account the needs of different functions and users. In this paper, we present QoS-aware offloading policies for serverless functions running in the Cloud-to-Edge continuum. We consider heterogeneous functions and service classes, and aim to maximize utility given a monetary budget for resource usage. Specifically, we introduce a two-level approach, where (i) FaaS nodes rely on a randomized policy to schedule every incoming request according to a set of probability values, and (ii) periodically, a linear programming model is solved to determine the probabilities to use for scheduling. We show by extensive simulation that our approach outperforms alternative approaches in terms of generated utility across multiple scenarios. Moreover, we demonstrate that our solution is computationally efficient and can be adopted in large-scale systems. We also demonstrate the functionality of our approach through a proof-of-concept experiment on an open-source FaaS framework
The positive impact of physical activity on working memory abilities: Evidence from a large Italian pre-adolescent sample
Physical activity (PA) is an essential component of people's well-being. Copious evidence argues for its protective effect across individuals' lifespan. However, its role as a factor of enhancement for human cognitive skills is still a matter of study. The present work aims to provide conclusive evidence about PA's role in modulating working memory skills in active pre-adolescent children. By enrolling a large number of participants, we tested the effect of PA on Digit Span Backwards (DSB), a well-consolidated test taxing primarily short-term auditory memory, i.e., less dependent on attention fluctuations. Higher working memory capacity was assumed to emerge in the participants practising PA compared to the less active ones. Moreover, due to the different activities participants reported to practice, we expected that children practising open-skill activities manifested better memory skills than the peers practising closed-skill activities, due to the intrinsic nature of the two forms of exercises. Data supported the previous hypothesis highlighting PA's positive effect; however, they did not keep the assumed differences for open vs closed skills. Results are discussed in the light of the cognitive efforts required to sport beginners, particularly in the light of what they are prompted to code, remember and recall in each step of the proposed exercises
Self-esteem in physically active middle school students
The present research examined the effect of physical fitness on self-esteem of pre-adolescent children. Students performed the MOTORFIT tests and filled IPAQ-C and Self-Esteem questionnaires. According to the level of the physical fitness we evaluated the self-esteem. Results showed no gender differences, while differences for the level of physical fitness was found. In particular, participants who performed better the MOTORFIT test reported a higher self-esteem compared to less physical fit participants. However, a discrepancy emerged when the self-esteem was analysed as a function of the physical activity reported where no differences emerged between the groups. In conclusion, our results provided an effect of physical activity on self-esteem through objective measures.
Key words: physical activity, pre-adolescent, psychosocial characteristics
The gravitational eikonal: from particle, string and brane collisions to black-hole encounters
Motivated by conceptual problems in quantum theories of gravity, the
gravitational eikonal approach, inspired by its electromagnetic predecessor,
has been successfully applied to the transplanckian energy collisions of
elementary particles and strings since the late eighties, and to string-brane
collisions in the past decade. After the direct detection of gravitational
waves from black-hole mergers, most of the attention has shifted towards
adapting these methods to the physics of black-hole encounters. For such
systems, the eikonal exponentiation provides an amplitude-based approach to
calculate classical gravitational observables, thus complementing more
traditional analytic methods such as the Post-Newtonian expansion, the
worldline formalism, or the Effective-One-Body approach. In this review we
summarize the main ideas and techniques behind the gravitational eikonal
formalism. We discuss how it can be applied in various different physical
setups involving particles, strings and branes and then we mainly concentrate
on the most recent developments, focusing on massive scalars minimally coupled
to gravity, for which we aim at being as self-contained and comprehensive as
possible.Comment: 208 pages, 19 figure
A post COVID lockdown pilot study on the effect of physical activity intensity on cognitive functions of children aged 6-8 years old
Physical activity practice is very important for individual\u2019s wealth status. Moreover, it is possible to consider physical activity one of the teachers\u2019 tool to improve the academic achievement and the cognitive functions in children. However, according to some evidences it seems that the physical activity at high intensity increase the cognitive functions compared to the low intensity physical activity. In this project, we investigate how the intensity of physical activity affects a series of cognitive functions such as Attention and Working Memory. Eleven participants of a summer camp participated at the study. Three experimental weeks with different physical intensities were involved (Standard Intensity, High intensity and Low Intensity). Participants performed the cognitive tasks at the beginning and at the end of each experimental week. Our results indicated an effect of the physical activity intensity in some kind of attention. Working Memory instead, was not affected. Thus, our results suggested that intensity could be an important factor to increase some cognitive functions, but not all of them
- …