4,713 research outputs found
Health Data and Privacy in the Digital Era
In 2010, the social networking site Facebook launched a platform allowing private companies to request users’ permission to access personal data. Few users were aware of the platform, which was integrated into Facebook’s terms of service. In 2014, Cambridge Analytica, a UK-based political consulting firm, developed a data-harvesting app. That app prompted Facebook users to provide psychological profiles, including responses such as “I get upset easily” and “I have frequent mood-swings” as part of a “research project.”
The Facebook platform allowed users to share their friends’ data as well, enabling Cambridge Analytica to access tens of millions of personal profiles, identifying voters’ political preferences. The controversy revealed risks to identifiable health data posed by social media and web services companies’ practices. After the Cambridge Analytica controversy, Facebook suspended a project that aimed to link data about users’ medical conditions with information about their social networks.
Individuals often reveal detailed, sensitive health information online. Through wearable devices, social media posts, traceable web searches, and online patient communities, users generate large volumes of health data. Although some individuals participate in online patient forums and wellness information sharing apps under their own names, others participate via pseudonyms, assuming their privacy is preserved. Many users believe their data will be shared only with those they designate
Interaction induced dimerization in zigzag single wall carbon nanotubes
We derive a low-energy effective model of metallic zigzag carbon nanotubes at
half filling. We show that there are three important features characterizing
the low-energy properties of these systems: the long-range Coulomb interaction,
umklapp scattering and an explicit dimerization generated by interactions. The
ratio of the dimerization induced gap and the Mott gap induced by the umklapp
interactions is dependent on the radius of the nanotube and can drive the
system through a quantum phase transition with SU(2)_1 quantum symmetry. We
consider the physical properties of the phases on either side of this
transition which should be relevant for realistic nanotubes.Comment: 8 pages, 5 figure
Customer mobility and congestion in supermarkets
The analysis and characterization of human mobility using population-level
mobility models is important for numerous applications, ranging from the
estimation of commuter flows in cities to modeling trade flows between
countries. However, almost all of these applications have focused on large
spatial scales, which typically range between intra-city scales to
inter-country scales. In this paper, we investigate population-level human
mobility models on a much smaller spatial scale by using them to estimate
customer mobility flow between supermarket zones. We use anonymized, ordered
customer-basket data to infer empirical mobility flow in supermarkets, and we
apply variants of the gravity and intervening-opportunities models to fit this
mobility flow and estimate the flow on unseen data. We find that a
doubly-constrained gravity model and an extended radiation model (which is a
type of intervening-opportunities model) can successfully estimate 65--70\% of
the flow inside supermarkets. Using a gravity model as a case study, we then
investigate how to reduce congestion in supermarkets using mobility models. We
model each supermarket zone as a queue, and we use a gravity model to identify
store layouts with low congestion, which we measure either by the maximum
number of visits to a zone or by the total mean queue size. We then use a
simulated-annealing algorithm to find store layouts with lower congestion than
a supermarket's original layout. In these optimized store layouts, we find that
popular zones are often in the perimeter of a store. Our research gives insight
both into how customers move in supermarkets and into how retailers can arrange
stores to reduce congestion. It also provides a case study of human mobility on
small spatial scales
The effect of a local perturbation in a fermionic ladder
We study the effect of a local external potential on a system of two parallel
spin-polarized nanowires placed close to each other. For single channel
nanowires with repulsive interaction we find that transport properties of the
system are highly sensitive to the transverse gradient of the perturbation: the
asymmetric part completely reflects the electrons leading to vanishing
conductance at zero temperature, while the flat potential remains transparent.
We envisage a possible application of this unusual property in the sensitive
measurement of local potential field gradients.Comment: 4+ pages, 2 figures, typos correcte
Fluoroquinolone-mediated inhibition of cell growth, S-G2/M cell cycle arrest, and apoptosis in canine osteosarcoma cell lines.
Despite significant advancements in osteosarcoma research, the overall survival of canine and human osteosarcoma patients has remained essentially static over the past 2 decades. Post-operative limb-spare infection has been associated with improved survival in both species, yet a mechanism for improved survival has not been clearly established. Given that the majority of canine osteosarcoma patients experiencing post-operative infections were treated with fluoroquinolone antibiotics, we hypothesized that fluoroquinolone antibiotics might directly inhibit the survival and proliferation of canine osteosarcoma cells. Ciprofloxacin or enrofloxacin were found to inhibit p21(WAF1) expression resulting in decreased proliferation and increased S-G(2)/M accumulation. Furthermore, fluoroquinolone exposure induced apoptosis of canine osteosarcoma cells as demonstrated by cleavage of caspase-3 and PARP, and activation of caspase-3/7. These results support further studies examining the potential impact of quinolones on survival and proliferation of osteosarcoma
GT strengths and electron-capture rates for pf-shell nuclei of relevance for late stellar evolution
This paper presents a systematic evaluation of the ability of theoretical
models to reproduce experimental Gamow-Teller transition strength distributions
measured via (n,p)-type charge-exchange reactions at intermediate beam
energies. The focus is on transitions from stable nuclei in the pf shell
(45<A<64). The impact of deviations between experimental and theoretical
Gamow-Teller strength distributions on derived stellar electron-capture rates
at densities and temperatures of relevance for Type Ia and Type II supernovae
is investigated. The theoretical models included in the study are based on the
shell-model, using the KB3G and GXPF1a interactions, and quasiparticle
random-phase approximation (QRPA) using ground-state deformation parameters and
masses from the finite-range droplet model.Comment: 25 pages, 27 figure
Strong correlation effects in single-wall carbon nanotubes
We present an overview of strong correlations in single-wall carbon
nanotubes, and an introduction to the techniques used to study them
theoretically. We concentrate on zigzag nanotubes, although universality
dictates that much ofthe theory can also be applied to armchair or chiral
nanotubes. We show how interaction effects lead to exotic low energy properties
and discuss future directions for studies on correlation effects in nanotubes
Should Species Distribution Models Account for Spatial Autocorrelation? A Test of Model Projections Across Eight Millennia of Climate Change
Aim: The distributions of many organisms are spatially autocorrelated, but it is unclear whether including spatial terms in species distribution models (SDMs) improves projections of species distributions under climate change. We provide one of the first comparative evaluations of the ability of a purely spatial SDM, a purely non-spatial SDM and a SDM that combines spatial and environmental information to project species distributions across eight millennia of climate change. Location: Eastern North America. Methods: To distinguish between the importance of climatic versus spatial explanatory variables we fit three Bayesian SDMs to modern occurrence data for Fagus and Tsuga, two tree genera whose distributions can be reliably inferred from fossil pollen: a spatially varying intercept model, a non-spatial model with climatic variables and a spatially varying intercept plus climate model. Using palaeoclimate data with a high temporal resolution, we hindcasted the SDMs in 1000-year time steps for 8000 years, and compared model projections with palynological data for the same periods. Results: For both genera, spatial SDMs provided better fits to the calibration data, more accurate predictions of a hold-out validation dataset of modern trees and higher variance in current predictions and hindcasted projections than non-spatial SDMs. Performance of non-spatial and spatial SDMs according to the area under the receiver operating curve varied by genus. For both genera, false negative rates between non-spatial and spatial models were similar, but spatial models had lower false positive rates than non-spatial models. Main conclusions: The inclusion of computationally demanding spatial random effects in SDMs may be warranted when ecological or evolutionary processes prevent taxa from shifting their distributions or when the cost of false positives is high.Organismic and Evolutionary Biolog
Proposal to inform European institutions regarding the regulation of conscientious objection to abortion.
The aim of this paper is to define a set of proposals to inform European institutions in the regulation of Conscientious Objection to abortion. The board of the European Society of Contraception and Reproductive Health Care (ESC) was informed on the elements that should in the opinion of the authors be included in a future regulation of Conscientious Objection to abortion in Europe. These elements are outlined in this paper and the debate about them could form the basis for recommendations to the international scientific community and the European institutions. As current measures governing the principle of conscientious objection result in negative consequences regarding women's access to sexual and reproductive health services, they should be changed. Healthcare services should adopt measures to guarantee that a woman's right to voluntary abortion is not limited by the practitioner's stance on the principle of conscientious objection. In the countries where conscientious objection is allowed, the regulation must clearly delineate the extent of the duties and the exemptions of professionals based on the principles of established social consensus. The recommendations included in this document specify measures on the rights of women, the rights and duties of the practitioner, the role of institutions and the role of professional associations
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