1,417 research outputs found

    Reconciling long-term cultural diversity and short-term collective social behavior

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    An outstanding open problem is whether collective social phenomena occurring over short timescales can systematically reduce cultural heterogeneity in the long run, and whether offline and online human interactions contribute differently to the process. Theoretical models suggest that short-term collective behavior and long-term cultural diversity are mutually excluding, since they require very different levels of social influence. The latter jointly depends on two factors: the topology of the underlying social network and the overlap between individuals in multidimensional cultural space. However, while the empirical properties of social networks are well understood, little is known about the large-scale organization of real societies in cultural space, so that random input specifications are necessarily used in models. Here we use a large dataset to perform a high-dimensional analysis of the scientific beliefs of thousands of Europeans. We find that inter-opinion correlations determine a nontrivial ultrametric hierarchy of individuals in cultural space, a result unaccessible to one-dimensional analyses and in striking contrast with random assumptions. When empirical data are used as inputs in models, we find that ultrametricity has strong and counterintuitive effects, especially in the extreme case of long-range online-like interactions bypassing social ties. On short time-scales, it strongly facilitates a symmetry-breaking phase transition triggering coordinated social behavior. On long time-scales, it severely suppresses cultural convergence by restricting it within disjoint groups. We therefore find that, remarkably, the empirical distribution of individuals in cultural space appears to optimize the coexistence of short-term collective behavior and long-term cultural diversity, which can be realized simultaneously for the same moderate level of mutual influence

    Fighting bisphenol a-induced male infertility: The power of antioxidants

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    Bisphenol A (BPA), a well-known endocrine disruptor present in epoxy resins and poly-carbonate plastics, negatively disturbs the male reproductive system affecting male fertility. In vivo studies showed that BPA exposure has deleterious effects on spermatogenesis by disturbing the hypothalamic–pituitary–gonadal axis and inducing oxidative stress in testis. This compound seems to disrupt hormone signalling even at low concentrations, modifying the levels of inhibin B, oestradiol, and testosterone. The adverse effects on seminal parameters are mainly supported by studies based on urinary BPA concentration, showing a negative association between BPA levels and sperm concentration, motility, and sperm DNA damage. Recent studies explored potential approaches to treat or prevent BPA-induced testicular toxicity and male infertility. Since the effect of BPA on testicular cells and spermatozoa is associated with an increased production of reactive oxygen species, most of the pharmacological approaches are based on the use of natural or synthetic antioxidants. In this review, we briefly describe the effects of BPA on male reproductive health and discuss the use of antioxidants to prevent or revert the BPA-induced toxicity and infertility in men.This research was funded by Institute for Biomedicine—iBiMED, grant number UID/BIM/04501/2020 and by individual grant from FCT of the Portuguese Ministry of Science and Higher Education to J.S. (SFRH/BD/136896/2018)

    Parametric Study of the Errors Obtained from the Measurement of the Oscillating Movement of a Bridge Using Image Processing

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    The movement of a pedestrian bridge retrieved by means of image processing technique has been analysed in this paper. An optical target has been attached to the deck and its oscillation has been tracked with fast cameras. The movement of the bridge has also been measured with a radar interferometer and this result has been taken as the reference signal. Using these data, a parametric study of the errors introduced by the image-based methods has been performed. The influence of some variables in the measurement error such as the distance to the target, the image size, the type of camera or the movement amplitude has been analysed for four different distances, and two types of excitations. Results show that the relative error decreases with the amplitude and the target diameter and it increases with the target distance. Additionally, the maximum relative error obtained in most of the analysed cases is below 10 %.The authors acknowledge the support of the Generalitat Valenciana through the project PROMETEO II/2015/015 and GV/2015/116 and the University of Alicante through the project GRE13-10

    Effect of Explosive Leg Power, Balance and Flexibility of The Wrist on Lay Up Shoot Ability in Basketball Athletes

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    This research is a type of Ex Post Facto research that uses a path analysis research design. The population is all basketball athletes PERBASI Kab. Sinjai with a total sample of 30 female athletes. The sampling technique is a saturated sample or the total population. The data analysis technique used was descriptive analysis, requirements test, path analysis through the SPSS 20.00 program at a significant level of 95% or α 0.05. The research results show that; (1) There is a direct effect of leg explosive power on wrist flexibility in basketball athletes in PERBASI Kab. Sinjai with a beta value of 0.603 with a significant level of 0.000 <α0.05; (2) There is a direct effect of balance on wrist flexibility in PERBASI athletes in Kab. Sinjai with a beta value of 0.378 with a significant level of 0.019 <α0.05; (3) There is a direct effect of leg explosive power on the ability to lay up shoot in basketball athletes from PERBASI Kab. Sinjai with a beta value of 0.380 with a significant level of 0.002 <α0.05 (4) There is a direct effect of balance on lay-up shoot ability in PERBASI Kab. Sinjai with a beta value of 0.289 with a significant level of 0.005 <α0.05; (5) There is a direct effect of wrist flexibility on the ability to lay up shoot in basketball athletes from PERBASI Kab. Sinjai with a beta value of 0.337 with a significant level of 0.004 <α0.05; (6) There is no effect of leg explosive power through wrist flexibility on the lay up shoot ability of PERBASI Kab. Sinjai with a beta value of 0.203 (0.203 <0.380); (7) There is no effect of balance through wrist flexibility on the lay up shoot ability of PERBASI Kab. Sinjai with a beta value of 0.127 (0.127 <0.28 9)

    Post-release mortality of shortfin mako in the Atlantic using satellite telemetry: preliminary results

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    This paper provides an update of the study on post-release mortality of the shortfin mako, Isurus oxyrinchus developed within the ICCAT Shark Research and Data Collection Program (SRDCP). Up to date, 34 tags (14 sPATs and 20 miniPATs) have been deployed by observers on Brazilian, Portuguese, Uruguayan, and US vessels in the temperate NE and NW, Equatorial and SW Atlantic. Data from 28 out of 34 tagged specimens could be used to obtain preliminary information regarding post-release mortality, resulting in a total of 7 mortality and 21 survival events.This study was carried out as part of a cooperative work conducted by the ICCAT Shark species group integrated in the ICCAT Shark Research and Data Collection Program (SRDCP). The authors are grateful to all fishery observers and longline skippers from the Nations involved in this study. Tags from additional sources have been contributed and deployed with several national Projects, specifically: Project "LL-Sharks: Mitigação das capturas de tubarões na pescaria de palangre de superfície (Ref: 31-03-05-FEP-44, funded by PROMAR)", Project "MAKO-WIDE - "A wide scale inter-hemispheric and inter-disciplinary study aiming the conservation of the shortfin mako shark in the Atlantic Ocean (Ref: FAPESP/19740/2014)", funded by FCT (Portuguese Foundation for Science and Technology) and FAPESP (São Paulo Research Foundation, Brazil), and Project SAFEWATERS SC7 (The provision of advice on the conservation of pelagic sharks associated to fishing activity under EU Sustainable Fisheries Partnership Agreements in the Atlantic Ocean) under the Framework Contract MARE/2012/21, funded by the European Commission. Additional satellite tags were acquired by NOAA in US-Uruguay and US-Portugal-Uruguay collaboration initiatives. Rui Coelho is supported by an Investigador-FCT contract from the Portuguese Foundation for Science and Technology (FCT) supported by the EU European Social Fund and the Programa Operacional Potencial Humano (Ref: IF/00253/2014).info:eu-repo/semantics/draf

    Assessment of connectivity-based resilience to attacks against multiple nodes in SDNs

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    In Software Defined Networks (SDNs), the control plane of a network is decoupled from its data plane. For scalability and robustness, the logically centralized control plane is implemented by physically placing different controllers throughout the network. The determination of the number and placement of controllers is known as the Controller Placement Problem (CPP). In the regular (i.e., failure-free) state, the control plane must guarantee a given maximum delay between every switch and its primary controller and a given maximum delay between every pair of controllers. In general, these delay bounds allow multiple solutions and, so, other goals can be used to determine the best CPP solution. In this paper, we assess the connectivity-based resilience to malicious attacks against multiple network nodes of the CPP solutions obtained with three different aims: the regular state delay optimization without any concern about attacks, the regular state delay optimization taking into consideration the worst-case attacks and the resilience optimization to attacks against multiple nodes. We assess the CPP solutions considering attacks of targeted nature (when the attacker has complete knowledge of the data plane) and attacks of non-targeted nature (i.e., random and epidemic attacks). We present computational results providing an analysis of the CPP solutions to the different types of attacks. The main conclusion is that the connectivity-based resilience between the different CPP solutions strongly depends on the network topology, the regular state delay bounds and the type of attacks. Finally, we provide insights on how SDN operators can consider the conducted assessment when deciding the controller placements in their networks.publishe

    Hamiltonian Forging of a Thermofield Double

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    We address the variational preparation of Gibbs states as the ground state of a suitably engineered Hamiltonian acting on the doubled Hilbert space. The construction is exact for quadratic fermionic Hamiltonians and gives excellent approximations up to fairly high quartic deformations. We provide a variational circuit whose optimization returns the unitary diagonalizing operator, thus giving access to the whole spectrum. The problem naturally implements the entanglement forging ansatz, allowing the computation of Thermofield Doubles with a higher number of qubits than in competing frameworks.Comment: 11 pages, 6 figure
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