423 research outputs found
Analytic Kramer kernels, Lagrange-type interpolation series and de Branges spaces
The classical Kramer sampling theorem provides a method for obtaining orthogonal sampling formulas. In particular, when the involved kernel is analytic in the sampling parameter it can be stated in an abstract setting of reproducing kernel Hilbert spaces of entire functions which includes as a particular case the classical Shannon sampling theory. This abstract setting allows us to obtain a sort of converse result and to characterize when the sampling formula associated with an analytic Kramer kernel can be expressed as a Lagrange-type interpolation series. On the other hand, the de Branges spaces of entire functions satisfy orthogonal sampling formulas which can be written as Lagrange-type interpolation series. In this work some links between all these ideas are established
Recommended age groups and frequency of mammography screening : a systematic review
Esta revisĂŁo teve por objetivo avaliar a
força de evidĂȘncia do atual indicador de desempenho
portuguĂȘs relativo ao rastreio do CĂąncer da
Mama através da mamografia, de modo a determinar
o grupo etĂĄrio e a periodicidade recomendadas.
Foram pesquisados artigos nas principais
bases de dados internacionais de literatura médica.
IncluĂmos artigos publicados entre Janeiro de
2006 e Janeiro de 2012 que correspondiam aos
objetivos da revisĂŁo. 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
trĂȘs revisĂ”es sistemĂĄticas (RS), uma meta-anĂĄlise
(MA) e uma norma de orientação clĂnica (NOC)
baseada numa RS. Os artigos selecionados avaliaram
a redução da mortalidade por cùncer da
mama através do rastreio com mamografia. A realização
do rastreio mamogrĂĄfico entre os 50 e os
69 anos Ă© recomendado em todos os artigos que
avaliam esta faixa etĂĄria. A NOC recomenda o
rastreio bienal. Em suma, a mamografia deverĂĄ
ser realizada entre os 50 e os 69 anos com uma
periodicidade bienal. Estes resultados vĂŁo ao encontro
do atual indicador de desempenho do rastreio
do cĂąncer 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
Lovelock theories, holography and the fate of the viscosity bound
We consider Lovelock theories of gravity in the context of AdS/CFT. We show
that, for these theories, causality violation on a black hole background can
occur well in the interior of the geometry, thus posing more stringent
constraints than were previously found in the literature. Also, we find that
instabilities of the geometry can appear for certain parameter values at any
point in the geometry, as well in the bulk as close to the horizon. These new
sources of causality violation and instability should be related to CFT
features that do not depend on the UV behavior. They solve a puzzle found
previously concerning unphysical negative values for the shear viscosity that
are not ruled out solely by causality restrictions. We find that, contrary to
previous expectations, causality violation is not always related to positivity
of energy. Furthermore, we compute the bound for the shear viscosity to entropy
density ratio of supersymmetric conformal field theories from d=4 till d=10 -
i.e., up to quartic Lovelock theory -, and find that it behaves smoothly as a
function of d. We propose an approximate formula that nicely fits these values
and has a nice asymptotic behavior when d goes to infinity for any Lovelock
gravity. We discuss in some detail the latter limit. We finally argue that it
is possible to obtain increasingly lower values for the shear viscosity to
entropy density ratio by the inclusion of more Lovelock terms.Comment: 42 pages, 17 figures, JHEP3.cls. v2: reference adde
Cervical cancer screening: target age bracket, screening frequency and screening method: review of recent evidence and comparison with the Portuguese performance indicator
Esta revisĂŁo teve por objetivo avaliar a força de evidĂȘncia do indicador de desempenho portuguĂȘs relativo ao rastreio do CĂąncer do Colo do Ătero (CCU): (1) limites etĂĄrios 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 excluĂdos os artigos que nĂŁo abordavam o objetivo da investigação ou que nĂŁo fossem redigidos em InglĂȘs, PortuguĂȘs ou Espanhol. Para interpretar os artigos selecionados foi utilizada a classificação SORT. Foram encontrados 197 artigos, dos quais seleccionados 9: 1 revisĂŁo sistemĂĄtica (RS), 1 estudo clĂnico controlado aleatorizado, 2 estudos observacionais retrospectivos e 5 normas de orientação clĂnica (NOC). Os autores optaram por incluir nesta revisĂŁo mais 4 NOCs e 2 RSs por considerarem ser relevantes para a população Portuguesa, apesar de nĂŁo resultarem da pesquisa efectuada. Os estudos sugerem realização do rastreio entre os 21 e 25 atĂ© aos 65 anos, com uma periodicidade trienal usando a citologia convencional. Existe ainda controvĂ©rsia no que toca aos 3 objetivos deste artigo (limites etĂĄrios, frequĂȘncia e mĂ©todo).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 TrypanosomeâTrypanosoma 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
Tear fluid biomarkers in ocular and systemic disease: potential use for predictive, preventive and personalised medicine
In the field of predictive, preventive and personalised medicine, researchers are keen to identify novel and reliable ways to predict and diagnose disease, as well as to monitor patient response to therapeutic agents. In the last decade alone, the sensitivity of profiling technologies has undergone huge improvements in detection sensitivity, thus allowing quantification of minute samples, for example body fluids that were previously difficult to assay. As a consequence, there has been a huge increase in tear fluid investigation, predominantly in the field of ocular surface disease. As tears are a more accessible and less complex body fluid (than serum or plasma) and sampling is much less invasive, research is starting to focus on how disease processes affect the proteomic, lipidomic and metabolomic composition of the tear film. By determining compositional changes to tear profiles, crucial pathways in disease progression may be identified, allowing for more predictive and personalised therapy of the individual. This article will provide an overview of the various putative tear fluid biomarkers that have been identified to date, ranging from ocular surface disease and retinopathies to cancer and multiple sclerosis. Putative tear fluid biomarkers of ocular disorders, as well as the more recent field of systemic disease biomarkers, will be shown
Easy-To-Synthesize Spirocyclic Compounds Possess Remarkable in Vivo Activity against Mycobacterium tuberculosis
Society urgently needs new, effective medicines for the treatment of tuberculosis. To kick-start the required hit-to-lead campaigns, the libraries of pharmaceutical companies have recently been evaluated for starting points. The GlaxoSmithKline (GSK) library yielded many high-quality hits, and the associated data were placed in the public domain to stimulate engagement by the wider community. One such series, the spiro compounds, are described here. The compounds were explored by a combination of traditional in-house research and open source methods. The series benefits from a particularly simple structure and a short associated synthetic chemistry route. Many members of the series displayed striking potency and low toxicity, and highly promising in vivo activity in a mouse model was confirmed with one of the analogues. Ultimately the series was discontinued due to concerns over safety, but the associated data remain public domain, empowering others to resume the series if the perceived deficiencies can be overcome
The Main Belt Comets and ice in the Solar System
We review the evidence for buried ice in the asteroid belt; specifically the questions around the so-called Main Belt Comets (MBCs). We summarise the evidence for water throughout the Solar System, and describe the various methods for detecting it, including remote sensing from ultraviolet to radio wavelengths. We review progress in the first decade of study of MBCs, including observations, modelling of ice survival, and discussion on their origins. We then look at which methods will likely be most effective for further progress, including the key challenge of direct detection of (escaping) water in these bodies
Conceptions of learning factors in postgraduate health sciences master students: a comparative study with nonhealth science students and between genders
Background: The studentsâ conceptions of learning in postgraduate health science master studies are poorly
understood. The aim of this study was to compare the factors influencing conceptions of learning in health
sciences and non-health sciences students enrolled in postgraduate master programs in order to obtain
information that may be useful for students and for future postgraduate programs.
Methods: A modified version of the Learning Inventory Conception Questionnaire (COLI) was used to compare
studentsâ conception learning factors in 131 students at the beginning of their postgraduate studies in health
sciences, experimental sciences, arts and humanities and social sciences.
Results: The present study demonstrates that a set of factors may influence conception of learning of health
sciences postgraduate students, with learning as gaining information, remembering, using, and understanding
information, awareness of duty and social commitment being the most relevant. For these students, learning as a
personal change, a process not bound by time or place or even as acquisition of professional competences, are less
relevant. According to our results, this profile is not affected by gender differences.
Conclusions: Our results show that the overall conceptions of learning differ among students of health sciences
and non-health sciences (experimental sciences, arts and humanities and social sciences) master postgraduate
programs. These finding are potentially useful to foster the learning process of HS students, because if they are
metacognitively aware of their own conception or learning, they will be much better equipped to self-regulate
their learning behavior in a postgraduate master program in health sciences.Supported by CTS-115 (Tissue Engineering Group of the University of Granada).
The funding body did not took part in the design of the study and collection,
analysis and interpretation of data and in writing the manuscript
Tumour Cannabinoid CB1 Receptor and Phosphorylated Epidermal Growth Factor Receptor Expression Are Additive Prognostic Markers for Prostate Cancer
BACKGROUND: In cultured prostate cancer cells, down-regulation of epidermal growth factor receptor (EGFR) has been implicated in mediating the antiproliferative effect of the endogenous cannabinoid (CB) ligand anandamide. Using a well-characterised cohort of prostate cancer patients, we have previously reported that expression levels of phosphorylated EGFR (pEGFR-IR) and CB(1) receptor (CB(1)IR) in tumour tissue at diagnosis are markers of disease-specific survival, but it is not known whether the two markers interact in terms of their influence on disease severity at diagnosis and disease outcome. METHODOLOGY/PRINCIPAL FINDINGS: Data from a cohort of 419 patients who were diagnosed with prostate cancer at transurethral resection for voiding difficulties was used. Scores for both tumour CB(1)IR and pEGFR-IR were available in the database. Of these, 235 had been followed by expectancy until the appearance of metastases. For patients scored for both parameters, Cox proportional-hazards regression analyses using optimal cut-off scores indicated that the two measures provided additional diagnostic information not only to each other, but to that provided by the tumour stage and the Gleason score. When the cases were divided into subgroups on the basis of these cut-off scores, the patients with both CB(1)IR and pEGFR-IR scores above their cut-off had a poorer disease-specific survival and showed a more severe pathology at diagnosis than patients with high pEGFR-IR scores but with CB(1)IR scores below the cut-off. CONCLUSIONS/SIGNIFICANCE: These data indicate that a high tumour CB(1) receptor expression at diagnosis augments the deleterious effects of a high pEGFR expression upon disease-specific survival
- âŠ