Gauss-Bonnet Black Holes and Heavy Fermion Metals

We consider charged black holes in Einstein-Gauss-Bonnet Gravity with Lifshitz boundary conditions. We find that this class of models can reproduce the anomalous specific heat of condensed matter systems exhibiting non-Fermi-liquid behaviour at low temperatures. We find that the temperature dependence of the Sommerfeld ratio is sensitive to the choice of Gauss-Bonnet coupling parameter for a given value of the Lifshitz scaling parameter. We propose that this class of models is dual to a class of models of non-Fermi-liquid systems proposed by Castro-Neto et.al.Comment: 17 pages, 6 figures, pdfLatex; small corrections to figure 10 in this versio

Recommended age groups and frequency of mammography screening : a systematic review

Esta revisão teve por objetivo avaliar a força de evidência do atual indicador de desempenho português relativo ao rastreio do Câncer da Mama através da mamografia, de modo a determinar o grupo etário e a periodicidade recomendadas. Foram pesquisados artigos nas principais bases de dados internacionais de literatura médica. Incluímos artigos publicados entre Janeiro de 2006 e Janeiro de 2012 que correspondiam aos objetivos da revisão. Foi utilizada a taxonomia SORT para a classificação dos resultados. Dos 253 artigos encontrados foram selecionados cinco que cumpriam os critérios de inclusão. Estes incluem três revisões sistemáticas (RS), uma meta-análise (MA) e uma norma de orientação clínica (NOC) baseada numa RS. Os artigos selecionados avaliaram a redução da mortalidade por câncer da mama através do rastreio com mamografia. A realização do rastreio mamográfico entre os 50 e os 69 anos é recomendado em todos os artigos que avaliam esta faixa etária. A NOC recomenda o rastreio bienal. Em suma, a mamografia deverá ser realizada entre os 50 e os 69 anos com uma periodicidade bienal. Estes resultados vão ao encontro do atual indicador de desempenho do rastreio do câncer da mama em Portugal.The scope of this review was to assess the strength of evidence for the current Portuguese performance indicator on breast cancer screening with mammography in order to determine the recommended age group and periodicity for screening. A search for articles was conducted in the main international databases of medical literature. Articles published between January 2006 and January 2012 addressing the objectives of this review were included. The SORT taxonomy was used to classify the results. Of the 253 articles, five articles met the inclusion criteria and were selected for review. These included three systematic reviews, one meta-analysis and one clinical guideline based on a systematic review. A reduction in breast cancer mortality with mamography screening was the outcome in all articles selected. Mammography screening between 50 and 69 years was recommended in all articles that assess this age group. The clinical guidelines recommended screening every two years. In conclusion, the current literature recommends mammography for women every two years between the ages of 50 and 69 years. This is consistent with the current performance indicator for breast cancer screening in Portugal

Isolation and fine mapping of Rps6: An intermediate host resistance gene in barley to wheat stripe rust

A plant may be considered a nonhost of a pathogen if all known genotypes of a plant species are resistant to all known isolates of a pathogen species. However, if a small number of genotypes are susceptible to some known isolates of a pathogen species this plant maybe considered an intermediate host. Barley (Hordeum vulgare) is an intermediate host for Puccinia striiformis f. sp. tritici (Pst), the causal agent of wheat stripe rust. We wanted to understand the genetic architecture underlying resistance to Pst and to determine whether any overlap exists with resistance to the host pathogen, Puccinia striiformis f. sp. hordei (Psh). We mapped Pst resistance to chromosome 7H and show that host and intermediate host resistance is genetically uncoupled. Therefore, we designate this resistance locus Rps6. We used phenotypic and genotypic selection on F2:3 families to isolate Rps6 and fine mapped the locus to a 0.1 cM region. Anchoring of the Rps6 locus to the barley physical map placed the region on two adjacent fingerprinted contigs. Efforts are now underway to sequence the minimal tiling path and to delimit the physical region harbouring Rps6. This will facilitate additional marker development and permit identification of candidate genes in the region

Cervical cancer screening: target age bracket, screening frequency and screening method: review of recent evidence and comparison with the Portuguese performance indicator

Esta revisão teve por objetivo avaliar a força de evidência do indicador de desempenho português relativo ao rastreio do Câncer do Colo do Útero (CCU): (1) limites etários das mulheres da população geral que o devem realizar, a (2) periodicidade com que deve ser realizado e (3) qual o melhor exame de rastreio. Foram pesquisados os seguintes termos MeSH: vaginal smears, age groups, periodicity, methods, uterine cervical cancer. Foram excluídos os artigos que não abordavam o objetivo da investigação ou que não fossem redigidos em Inglês, Português ou Espanhol. Para interpretar os artigos selecionados foi utilizada a classificação SORT. Foram encontrados 197 artigos, dos quais seleccionados 9: 1 revisão sistemática (RS), 1 estudo clínico controlado aleatorizado, 2 estudos observacionais retrospectivos e 5 normas de orientação clínica (NOC). Os autores optaram por incluir nesta revisão mais 4 NOCs e 2 RSs por considerarem ser relevantes para a população Portuguesa, apesar de não resultarem da pesquisa efectuada. Os estudos sugerem realização do rastreio entre os 21 e 25 até aos 65 anos, com uma periodicidade trienal usando a citologia convencional. Existe ainda controvérsia no que toca aos 3 objetivos deste artigo (limites etários, frequência e método).The scope of this review was to assess the strength of evidence of Portuguese performance indicators on Cervical Cancer screening: (1) age group of the women that should be screened for cervical cancer; (2) frequency of screening; and (3) the best method for screening. The following MeSH terms were searched: vaginal smears, age groups, periodicity, methods, uterine cervical cancer. Articles not reflecting the study objectives or not available in English, Portuguese or Spanish were excluded. The SORT classification was used to rate the articles selected.Of the 197 articles found, 9 that met all study criteria were selected for inclusion in this review. These included 1 systematic review, 1 randomized controlled clinical trial, 2 retrospective studies and 5 clinical guidelines. The authors also chose to include 4 clinical guidelines and two systematic reviews relevant to the Portuguese population even though they did not appear in the initial search of the literature. The studies suggest screening women between the ages of 21 to 25 years and 65 years of age, once every three years using conventional cytology. There is still controversy regarding the three objectives of this study (target age bracket, screening frequency and screening method)

Genome of the Avirulent Human-Infective Trypanosome—Trypanosoma rangeli

Background: Trypanosoma rangeli is a hemoflagellate protozoan parasite infecting humans and other wild and domestic mammals across Central and South America. It does not cause human disease, but it can be mistaken for the etiologic agent of Chagas disease, Trypanosoma cruzi. We have sequenced the T. rangeli genome to provide new tools for elucidating the distinct and intriguing biology of this species and the key pathways related to interaction with its arthropod and mammalian hosts.  Methodology/Principal Findings: The T. rangeli haploid genome is ,24 Mb in length, and is the smallest and least repetitive trypanosomatid genome sequenced thus far. This parasite genome has shorter subtelomeric sequences compared to those of T. cruzi and T. brucei; displays intraspecific karyotype variability and lacks minichromosomes. Of the predicted 7,613 protein coding sequences, functional annotations could be determined for 2,415, while 5,043 are hypothetical proteins, some with evidence of protein expression. 7,101 genes (93%) are shared with other trypanosomatids that infect humans. An ortholog of the dcl2 gene involved in the T. brucei RNAi pathway was found in T. rangeli, but the RNAi machinery is non-functional since the other genes in this pathway are pseudogenized. T. rangeli is highly susceptible to oxidative stress, a phenotype that may be explained by a smaller number of anti-oxidant defense enzymes and heatshock proteins.  Conclusions/Significance: Phylogenetic comparison of nuclear and mitochondrial genes indicates that T. rangeli and T. cruzi are equidistant from T. brucei. In addition to revealing new aspects of trypanosome co-evolution within the vertebrate and invertebrate hosts, comparative genomic analysis with pathogenic trypanosomatids provides valuable new information that can be further explored with the aim of developing better diagnostic tools and/or therapeutic targets

Preoperative biliary drainage for periampullary tumors causing obstructive jaundice; DRainage vs. (direct) OPeration (DROP-trial)

BACKGROUND: Surgery in patients with obstructive jaundice caused by a periampullary (pancreas, papilla, distal bile duct) tumor is associated with a higher risk of postoperative complications than in non-jaundiced patients. Preoperative biliary drainage was introduced in an attempt to improve the general condition and thus reduce postoperative morbidity and mortality. Early studies showed a reduction in morbidity. However, more recently the focus has shifted towards the negative effects of drainage, such as an increase of infectious complications. Whether biliary drainage should always be performed in jaundiced patients remains controversial. The randomized controlled multicenter DROP-trial (DRainage vs. Operation) was conceived to compare the outcome of a 'preoperative biliary drainage strategy' (standard strategy) with that of an 'early-surgery' strategy, with respect to the incidence of severe complications (primary-outcome measure), hospital stay, number of invasive diagnostic tests, costs, and quality of life. METHODS/DESIGN: Patients with obstructive jaundice due to a periampullary tumor, eligible for exploration after staging with CT scan, and scheduled to undergo a "curative" resection, will be randomized to either "early surgical treatment" (within one week) or "preoperative biliary drainage" (for 4 weeks) and subsequent surgical treatment (standard treatment). Primary outcome measure is the percentage of severe complications up to 90 days after surgery. The sample size calculation is based on the equivalence design for the primary outcome measure. If equivalence is found, the comparison of the secondary outcomes will be essential in selecting the preferred strategy. Based on a 40% complication rate for early surgical treatment and 48% for preoperative drainage, equivalence is taken to be demonstrated if the percentage of severe complications with early surgical treatment is not more than 10% higher compared to standard treatment: preoperative biliary drainage. Accounting for a 10% dropout, 105 patients are needed in each arm resulting in a study population of 210 (alpha = 0.95, beta = 0.8). DISCUSSION: The DROP-trial is a randomized controlled multicenter trial that will provide evidence whether or not preoperative biliary drainage is to be performed in patients with obstructive jaundice due to a periampullary tumor