240 research outputs found
d=3 Bosonic Vector Models Coupled to Chern-Simons Gauge Theories
We study three dimensional O(N)_k and U(N)_k Chern-Simons theories coupled to
a scalar field in the fundamental representation, in the large N limit. For
infinite k this is just the singlet sector of the O(N) (U(N)) vector model,
which is conjectured to be dual to Vasiliev's higher spin gravity theory on
AdS_4. For large k and N we obtain a parity-breaking deformation of this
theory, controlled by the 't Hooft coupling lambda = 4 \pi N / k. For infinite
N we argue (and show explicitly at two-loop order) that the theories with
finite lambda are conformally invariant, and also have an exactly marginal
(\phi^2)^3 deformation.
For large but finite N and small 't Hooft coupling lambda, we show that there
is still a line of fixed points parameterized by the 't Hooft coupling lambda.
We show that, at infinite N, the interacting non-parity-invariant theory with
finite lambda has the same spectrum of primary operators as the free theory,
consisting of an infinite tower of conserved higher-spin currents and a scalar
operator with scaling dimension \Delta=1; however, the correlation functions of
these operators do depend on lambda. Our results suggest that there should
exist a family of higher spin gravity theories, parameterized by lambda, and
continuously connected to Vasiliev's theory. For finite N the higher spin
currents are not conserved.Comment: 34 pages, 29 figures. v2: added reference
The , , and mesons in a double pole QCD Sum Rule
We use the method of double pole QCD sum rule which is basically a fit with
two exponentials of the correlation function, where we can extract the masses
and decay constants of mesons as a function of the Borel mass. We apply this
method to study the mesons: , , and
. We also present predictions for the toponiuns masses
of m(1S)=357 GeV and m(2S)=374 GeV.Comment: 14 pages, 11 figures in Braz J Phys (2016
Approaches in biotechnological applications of natural polymers
Natural polymers, such as gums and mucilage, are biocompatible, cheap, easily available and non-toxic materials of native origin. These polymers are increasingly preferred over synthetic materials for industrial applications due to their intrinsic properties, as well as they are considered alternative sources of raw materials since they present characteristics of sustainability, biodegradability and biosafety. As definition, gums and mucilages are polysaccharides or complex carbohydrates consisting of one or more monosaccharides or their derivatives linked in bewildering variety of linkages and structures. Natural gums are considered polysaccharides naturally occurring in varieties of plant seeds and exudates, tree or shrub exudates, seaweed extracts, fungi, bacteria, and animal sources. Water-soluble gums, also known as hydrocolloids, are considered exudates and are pathological products; therefore, they do not form a part of cell wall. On the other hand, mucilages are part of cell and physiological products. It is important to highlight that gums represent the largest amounts of polymer materials derived from plants. Gums have enormously large and broad applications in both food and non-food industries, being commonly used as thickening, binding, emulsifying, suspending, stabilizing agents and matrices for drug release in pharmaceutical and cosmetic industries. In the food industry, their gelling properties and the ability to mold edible films and coatings are extensively studied. The use of gums depends on the intrinsic properties that they provide, often at costs below those of synthetic polymers. For upgrading the value of gums, they are being processed into various forms, including the most recent nanomaterials, for various biotechnological applications. Thus, the main natural polymers including galactomannans, cellulose, chitin, agar, carrageenan, alginate, cashew gum, pectin and starch, in addition to the current researches about them are reviewed in this article.. }To the Conselho Nacional de Desenvolvimento Cientfíico e Tecnológico (CNPq) for fellowships (LCBBC and MGCC) and the Coordenação de Aperfeiçoamento de Pessoal de Nvíel Superior (CAPES) (PBSA). This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit, the Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and COMPETE 2020 (POCI-01-0145-FEDER-006684) (JAT)
Multi-messenger observations of a binary neutron star merger
On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta
Neurocysticercosis in Paraiba, northeast Brazil: an endemic area?
Neurocysticercosis is the central nervous system infestation by Cysticercus cellulosae, the larval form of Taenia solium. It is related to poor hygiene habits and sanitation; although Northeast is poorest Region of Brazil, it has been always stated as a non-endemic area. After the installation of computed tomography (CT) service, the incidence of neurocysticercosis began to raise in neurology services in Campina Grande PB, a city where people from the interior Paraíba can find specialized medical facilities. We analyse 5,883 CT record of the TomoHPI Computed Tomography Service from August 1993 to December 1995, observing 1.02% suggestive neurocysticercosis cases and classified them according to sex and age, precedence and socioeconomic condition. Distribution of cases according to age is homogeneous until the age of 50 (mean: 28.36 years old). Men and women are equally affected. Urban areas inhabitants represented 83.33%. Residents of Campina Grande represented 48.33% and 48.34% were residents of cities around Campina Grande (until 50 Km around) and other cities of Paraíba State. Fifty-eight patients were dependent to public health care system. We conclude that neurocysticercosis seems to be endemic in Paraíba State, demanding a more detailed study to determine its incidence/prevalence.Neurocisticercose é a infestação do sistema nervoso central pelo Cysticercus cellulosae, a forma larval da Taenia solium. É relacionada a hábitos higiênicos e sanitários precários; embora o Nordeste seja a Região mais pobre do Brasil, foi sempre considerada área não-endêmica para neurocisticercose. Depois da instalação de um serviço de tomografia computadorizada (TC), a incidência da neurocisticercose começou a crescer nos serviços de neurologia em Campina Grande PB, cidade para onde confluem pessoas de todo o interior paraibano à procura de serviços médicos especializados. Analisamos 5.883 TC realizadas no Serviço TomoHPI de Radioimagem do Hospital Pedro I de agosto de 1993 até dezembro de 1995 e 1,02% foram diagnosticadas como sugestivas de neurocisticercose e classificadas de acordo com idade e sexo, procedência e condições sócio-econômicas. A distribuição dos casos de acordo com a idade é homogênea até os 50 anos de idade (média: 28,36 anos). Homens e mulheres são afetados igualmente. Procedentes de áreas urbanas representam 83.33%. Residentes em Campina Grande representam 48.33% do total; 48,34% residem em cidades ao redor de Campina Grande (até 50 Km de distância) ou em outras cidades da Paraíba. Cincoenta e oito pacientes são dependentes do Sistema Único de Saúde. Concluimos que a neurocisticercose parece ser endêmica em nosso Estado, sendo necessários estudos mais detalhados para que tal assertiva possa ser confirmada
Traditional knowledge and cultural importance of Borassus aethiopum Mart. in Benin: interacting effects of socio-demographic attributes and multi-scale abundance
ResearchBackground: Eliciting factors affecting distribution of traditional knowledge (TK) and cultural importance of plant
resources is central in ethnobiology. Socio-demographic attributes and ecological apparency hypothesis (EAH) have
been widely documented as drivers of TK distribution, but their synergistic effect is poorly documented. Here, we
focused on Borassus aethiopum, a socio-economic important agroforestry palm in Africa, analyzing relationships
between the number of use-reports and cultural importance on one hand, and informant socio-demographic
attributes (age category and gender) on the other hand, considering the EAH at multi-scale contexts. Our
hypothesis is that effects of socio-demographic attributes on use-reports and cultural importance are shaped by
both local (village level) and regional (chorological region level) apparency of study species. We expected so
because distribution of knowledge on a resource in a community correlates to the versatility in the resource
utilization but also connections among communities within a region.
Methods: Nine hundred ninety-two face-to-face individual semi-structured interviews were conducted in six villages of
low versus high local abundance of B. aethiopum spanning three chorological regions (humid, sub-humid and semiarid)
also underlying a gradient of increasing distribution and abundance of B. aethiopum. Number of use-reports and
score of importance of uses of B. aethiopum were recorded in six use-categories including medicine, food, handcraft,
construction, firewood, and ceremonies and rituals. Data were analyzed using Poisson and ordered logistic modelsinfo:eu-repo/semantics/publishedVersio
História da felariose linfática em Pernambuco: I. Aspectos epidemiológicos e de controle
Latex fluids are endowed with insect repellent activity not specifically related to their proteins or volatile substances
Analysis for genotyping Duffy blood group in inhabitants of Sudan, the Fourth Cataract of the Nile
<p>Abstract</p> <p>Background</p> <p>Genetic polymophisms of the Duffy antigen receptor for the chemokines (DARC) gene successfully protected against blood stage infection by <it>Plasmodium vivax </it>infection. The Fy (a-, b-) phenotype is predominant among African populations, particularly those originating from West Africa, and it is rare among non-African populations. The aim of this study was to analyse the frequency of four Duffy blood groups based on SNPs (T-33C, G125A, G298A and C5411T) in two local tribes of Sudanese Arabs, the <it>Shagia </it>and <it>Manasir</it>, which are both from the region of the Fourth Nile cataract in Sudan.</p> <p>Methods</p> <p>An analysis of polymorphisms was performed on 217 individuals (126 representatives of the <it>Shagia </it>tribe and 91 of the <it>Manasir)</it>. Real-time PCR and TaqMan Genotyping Assays were used to study the prevalence of alleles and genotypes.</p> <p>Results</p> <p>The analysis of allelic and genotype frequency in the T-33C polymorphisms demonstrated a significant dominance of the <it>C </it>allele and <it>CC </it>genotype (OR = 0.53 [0.32-0.88]; p = 0.02) in both tribes. The G125A polymorphism is associated with phenotype Fy(a-, b-) and was identified in 83% of <it>Shagia </it>and 77% of <it>Manasir</it>. With regard to G298A polymorphisms, the genotype frequencies were different between the tribes (p = 0,002) and no single <it>AA </it>homozygote was found. Based on four SNPs examined, 20 combinations of genotypes for the <it>Shagia </it>and <it>Manasir </it>tribes were determined. The genotype <it>CC/AA/GG/CT </it>occurred most often in <it>Shagia </it>tribe (45.9%) but was rare in the <it>Manasir </it>tribe (6.6%) (p < 0.001 <it>Shagia </it>versus <it>Manasir</it>). The <it>FY*A<sup>ES </sup></it>allele was identified in both analysed tribes. The presence of individuals with the <it>FY*A/FY*A </it>genotype was demonstrated only in the <it>Shagia </it>tribe.</p> <p>Conclusion</p> <p>This is probably the first report showing genotypically Duffy-negative people who carry both <it>FY*B<sup>ES </sup></it>and <it>FY*A<sup>ES</sup></it>. The identification of the <it>FY*A<sup>ES </sup></it>allele in both tribes may be due to admixture of the non-African genetic background. Taken as a whole, allele and genotype frequencies between the <it>Shagia </it>and the <it>Manasir </it>were statistically different. However, the presence of individuals with the <it>FY*A/FY*A </it>genotype was demonstrated only in the <it>Shagia </it>tribe.</p
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