54,748 research outputs found
Fatty-acid uptake in prostate cancer cells using dynamic microfluidic raman technology
It is known that intake of dietary fatty acid (FA) is strongly correlated with prostate cancer progression but is highly dependent on the type of FAs. High levels of palmitic acid (PA) or arachidonic acid (AA) can stimulate the progression of cancer. In this study, a unique experimental set-up consisting of a Raman microscope, coupled with a commercial shear-flow microfluidic system is used to monitor fatty acid uptake by prostate cancer (PC-3) cells in real-time at the single cell level. Uptake of deuterated PA, deuterated AA, and the omega-3 fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) were monitored using this new system, while complementary flow cytometry experiments using Nile red staining, were also conducted for the validation of the cellular lipid uptake. Using this novel experimental system, we show that DHA and EPA have inhibitory effects on the uptake of PA and AA by PC-3 cells
Discrimination against Mixed-Status Families and its Health Impact on Latino Children
Background and Objective: Restrictive immigration policies and discrimination are associated with negative health outcomes for immigrant and Latino families. Mixed-status families represent a unique subpopulation of Latinos affected by restrictive immigration policies. This qualitative study explored discrimination against mixed-status families and its potential health impact on Latino children from the perspective of Latina mothers.
Methods: In 2017, twenty in-depth interviews with Latina mothers of mixed-status families living in northwestern North Carolina were conducted, transcribed, and analyzed. Constant comparison, an approach to grounded theory development, was used.
Results: Nine themes emerged that reflected experiences with discrimination and its negative impact on children. Themes included more frequent and severe discrimination during and after the 2016 US presidential election, determination to stay together and remain in the US, experiences of discrimination in multiple settings, the impact of discrimination on child health and well-being, the impact of fear and stress on meeting the needs of children, the burden on children serving as liaisons between families and services, the inability of citizenship to protect against the effects of discrimination, positive and hopeful responses to discrimination, and the potential role of education in building a foundation for reducing discrimination (and thus promoting the health and well-being of Latino children) in the future.
Conclusions: Discrimination against mixed-status Latino families constitutes a critical threat to the health and well-being of Latino children. Further research should inform immigration policies that support (rather than threaten) the health, well-being, and health care practices that mitigate the stresses experienced by Latino children
Validation of Dunbar's number in Twitter conversations
Modern society's increasing dependency on online tools for both work and
recreation opens up unique opportunities for the study of social interactions.
A large survey of online exchanges or conversations on Twitter, collected
across six months involving 1.7 million individuals is presented here. We test
the theoretical cognitive limit on the number of stable social relationships
known as Dunbar's number. We find that users can entertain a maximum of 100-200
stable relationships in support for Dunbar's prediction. The "economy of
attention" is limited in the online world by cognitive and biological
constraints as predicted by Dunbar's theory. Inspired by this empirical
evidence we propose a simple dynamical mechanism, based on finite priority
queuing and time resources, that reproduces the observed social behavior.Comment: 8 pages, 6 figure
Fast Scalable Construction of (Minimal Perfect Hash) Functions
Recent advances in random linear systems on finite fields have paved the way
for the construction of constant-time data structures representing static
functions and minimal perfect hash functions using less space with respect to
existing techniques. The main obstruction for any practical application of
these results is the cubic-time Gaussian elimination required to solve these
linear systems: despite they can be made very small, the computation is still
too slow to be feasible.
In this paper we describe in detail a number of heuristics and programming
techniques to speed up the resolution of these systems by several orders of
magnitude, making the overall construction competitive with the standard and
widely used MWHC technique, which is based on hypergraph peeling. In
particular, we introduce broadword programming techniques for fast equation
manipulation and a lazy Gaussian elimination algorithm. We also describe a
number of technical improvements to the data structure which further reduce
space usage and improve lookup speed.
Our implementation of these techniques yields a minimal perfect hash function
data structure occupying 2.24 bits per element, compared to 2.68 for MWHC-based
ones, and a static function data structure which reduces the multiplicative
overhead from 1.23 to 1.03
Emissions from the combustion of torrefied and raw biomass fuels in a domestic heating stove
Biomass (pellets, briquettes, logs) are a key contributor to many countries' strategies for decarbonising heat, particularly in domestic applications. The emissions from these small devices can be high and severely impact air quality, but their levels depend on the design, control, abatement and fuel options. This paper is concerned with the last case. A comparative study shows the emissions from a domestic wood stove for three biomass fuels and their torrefied counterparts. The fuels were burned in a multi-fuel stove along with two reload batches creating continuous combustion cycles: the initial cold start data is presented but not included in averaging and calculation of emission factors. Measurements were made using an FTIR instrument for carbon and nitrogen based gaseous emissions, particulates were measured using a smoke meter with micro-quartz filters as well as a size-selective impactor to obtain the particle size distribution. Particulate emissions were significantly reduced from the torrefied fuels and this is thought to be related to their pyrolysis fingerprint, which was investigated by pyrolysis-GC–MS. NOx was slightly reduced, despite increased fuel-N after torrefaction. In addition, the reduced moisture in the torrefied fuels decreases emissions of CO and CH4 because of increased time of flaming combustion
Global Charges in Chern-Simons theory and the 2+1 black hole
We use the Regge-Teitelboim method to treat surface integrals in gauge
theories to find global charges in Chern-Simons theory. We derive the affine
and Virasoro generators as global charges associated with symmetries of the
boundary. The role of boundary conditions is clarified. We prove that for
diffeomorphisms that do not preserve the boundary there is a classical
contribution to the central charge in the Virasoro algebra. The example of
anti-de Sitter 2+1 gravity is considered in detail.Comment: Revtex, no figures, 26 pages. Important changes introduced. One
section added
Combining polynomial chaos expansions and genetic algorithm for the coupling of electrophysiological models
The number of computational models in cardiac research has grown over the last decades. Every year new models with di erent assumptions appear in the literature dealing with di erences in interspecies cardiac properties. Generally, these new models update the physiological knowledge using new equations which reect better the molecular basis of process. New equations require the fi tting of parameters to previously known experimental data or even, in some cases, simulated data. This work studies and proposes a new method of parameter adjustment based on Polynomial Chaos and Genetic Algorithm to nd the best values for the parameters upon changes in the formulation of ionic channels. It minimizes the search space and the computational cost combining it with a Sensitivity Analysis. We use the analysis of di ferent models of L-type calcium channels to see that by reducing the number of parameters, the quality of the Genetic Algorithm dramatically improves. In addition, we test whether the use of the Polynomial Chaos Expansions improves the process of the Genetic Algorithm search. We conclude that it reduces the Genetic Algorithm execution in an order of 103 times in the case studied here, maintaining the quality of the results. We conclude that polynomial chaos expansions can improve and reduce the cost of parameter adjustment in the development of new models.Peer ReviewedPostprint (author's final draft
Aspects of Black Hole Quantum Mechanics and Thermodynamics in 2+1 Dimensions
We discuss the quantum mechanics and thermodynamics of the (2+1)-dimensional
black hole, using both minisuperspace methods and exact results from
Chern-Simons theory. In particular, we evaluate the first quantum correction to
the black hole entropy. We show that the dynamical variables of the black hole
arise from the possibility of a deficit angle at the (Euclidean) horizon, and
briefly speculate as to how they may provide a basis for a statistical picture
of black hole thermodynamics.Comment: 20 pages and 2 figures, LaTeX, IASSNS-HEP-94/34 and UCD-94-1
Developpement des systemes de production innovants d’association mais/legumineuses dans la zone subhumide du Mali
Parmi les 3 piliers de l’intégration agriculture-élevage (traction animale, fumure organique, cultures fourragères) diffusés en Afrique de l’Ouest, seules les cultures fourragères ont été peu adoptées. Pourtant, les associations maïs/légumineuses ont l’avantage d’améliorer la production et l’alimentation animale. Elles représentent une alternative dans la gestion des risques et des incertitudes pour les agro-éleveurs, confrontés aux changements globaux (climatiques, pression foncière, dégradation des ressources naturelles). L’objectif de cette étude est de déterminer la contribution des associations maïs/légumineuses dans l’amélioration de la production de maïs grain et le bilan fourrager des exploitations agricoles. Le dispositif en blocs dispersés chez 10 producteurs, a consisté en 3 traitements, T1 (maïs seul), T2 (maïs/ niébé) et T3 (maïs/mucuna) durant 2 campagnes agricoles. En 2013 - 2014, les rendements de maïs grain ont été de 2433 kg/ha et en biomasse 2597 kgMS/ha. Par contre, en 2014 - 2015 les rendements ont été de 1932 kg/ha de maïs grain et de 5134 kgMS/ha de biomasse. Les besoins en matière sèche pour 90 jours de supplémentation ont été de 4,62 UBT en 2013 - 2014 et de 9,13 UBT en 2014 - 2015. Ces résultats montrent la contribution des associations maïs/légumineuses dans l’amélioration du rendement de maïs grain et de fourrages dans la zone subhumide au Mali.Mots clés : légumineuses, maïs, fourrage, Mal
Comparison of Sex Specific Data among Hospitalized Covid-19 Patients
It is critical to identify factors that contribute to disease severity among patients diagnosed with COVID-19. A systematic review of sex specific COVID-19 clinical outcomes demonstrated that female patients have lower rates of severe infection and mortality. This study investigates the correlation between biological sex and predisposing conditions as well as COVID-19 disease severity among 689 patients hospitalized within the St. Luke’s Hospital Network in Eastern PA/Western NJ. The sample is comprised of 45.8% female participants, of whom 30.2% identify as Hispanic or Latino, and 57.9% identidied their race as caucasian. Mean age of participants is 64.0 years (+/- 16.7). Data was extracted from patients electronic medical records both during their admission and after discharge. Chi squared test of independence was performed to examine the relation between known COVID-19 risk factors and COVID-19 infected female patients (n=314) compared to male patients (n=373). Risk factors stratied by biological sex showed that female patients were more likely to have COPD (p \u3c 0.05) and asthma (p \u3c 0.001), and less likely to have smoke exposure (p \u3c 0.05). There was no statistically significant difference in disease severity between the sexes with respect to intubation rate (p = 0.07) and mortality (p = 0.59). The results of this study are important to show that the trend of increased severity among males is not ubiquitous. Limitations of this study include small sample size, ongoing treatment protocol modifications with provider treatment bias, and overrepresentation of obesity.https://jdc.jefferson.edu/sexandgenderhealth/1036/thumbnail.jp
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