Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 17 de 17
Filtrar
Mais filtros

País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Clin Colon Rectal Surg ; 30(4): 277-280, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28924402

RESUMO

Colorectal surgeons have lagged behind other professionals in the use of social media. Currently, Twitter is the most widely utilized social platform for professional purposes among them. Connection and contagion are the two key actions that, together with immediate feedback and quantifiable impact, favor the use of Twitter over other social networks. In early 2016, a group of colorectal surgeons launched the #colorectalsurgery hashtag and, in less than 1 year, the ecosystem has incorporated over 2,600 users that generated over 24,000 tweets and 100 million impressions. "Live-Tweeting" surgical conferences by attendees including institutional or society accounts have greatly contributed to the success of the initiative. However, there are some barriers to a more wide adoption of social media, such as misrepresentation of non-peer-reviewed data, challenges to intellectual property protection, or even damage to the professional image. Active engagement with the #colorectalsurgery community may result in benefits for the global surgery community through information sharing, social interactions, personal branding, and research.

2.
Glob Chang Biol ; 20(1): 61-75, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23966281

RESUMO

Migrations between different habitats are key events in the lives of many organisms. Such movements involve annually recurring travel over long distances usually triggered by seasonal changes in the environment. Often, the migration is associated with travel to or from reproduction areas to regions of growth. Young anadromous Atlantic salmon (Salmo salar) emigrate from freshwater nursery areas during spring and early summer to feed and grow in the North Atlantic Ocean. The transition from the freshwater ('parr') stage to the migratory stage where they descend streams and enter salt water ('smolt') is characterized by morphological, physiological and behavioural changes where the timing of this parr-smolt transition is cued by photoperiod and water temperature. Environmental conditions in the freshwater habitat control the downstream migration and contribute to within- and among-river variation in migratory timing. Moreover, the timing of the freshwater emigration has likely evolved to meet environmental conditions in the ocean as these affect growth and survival of the post-smolts. Using generalized additive mixed-effects modelling, we analysed spatio-temporal variations in the dates of downstream smolt migration in 67 rivers throughout the North Atlantic during the last five decades and found that migrations were earlier in populations in the east than the west. After accounting for this spatial effect, the initiation of the downstream migration among rivers was positively associated with freshwater temperatures, up to about 10 °C and levelling off at higher values, and with sea-surface temperatures. Earlier migration occurred when river discharge levels were low but increasing. On average, the initiation of the smolt seaward migration has occurred 2.5 days earlier per decade throughout the basin of the North Atlantic. This shift in phenology matches changes in air, river, and ocean temperatures, suggesting that Atlantic salmon emigration is responding to the current global climate changes.


Assuntos
Migração Animal , Mudança Climática , Salmo salar/fisiologia , Animais , Clorofila/análise , Clorofila A , Oceanos e Mares , Rios , Temperatura , Fatores de Tempo
3.
Mar Environ Res ; 202: 106808, 2024 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-39467369

RESUMO

Clams, razor clams and cockle are intertidal bivalve species collected on foot in the shellfish grounds of the Rías Altas (NW Spain). Spatio-temporal distribution of these bivalves are typically at the expenses of the environmental conditions of the region; however, the responses to the abiotic conditions are poorly understood. Using data from 6 species (Ruditapes decussatus, Venerupis corrugata, Ruditapes philippinarum, Cerastoderam edule, Donax trunculus and Solen marginatus) sampled in 51 intertidal shellfish grounds during 2007 and 2008, we characterized the influence of the environment (temperature, salinity, nutrient salts, suspended organic matter, or sediment granulometry and composition) on the distribution and size of these species through a comparative statistical analysis. Shellfish grounds were grouped according to their sediment and water characteristics revealing a land-ocean gradient and the influence of the geological imprint that separates bivalve grounds from West to East. Statistical models showed that R. decussatus, V. corrugata and R. philippinarum together with C. edule were more abundant in sites combining a strong marine influence with organic-rich finer sediments. However, each of those species also had different environmental niches mostly related to their particular sediment affinities, the proximity to the river mouth, and their physiological tolerances to temperature and salinity. D. trunculus was only found in outer exposed shellfish grounds, while S. marginatus abundance increased in muddy sediments. River distance was a sound descriptor of individual shell length and length variability with contrasting effects on the different species. Furthermore, slopes of length-weight relationships were steeper in autumn than in spring, and this allometry tended to be more positive in sites located closer to the rivers' mouth, which had a higher organic matter C/N ratio. Overall, harvested intertidal bivalves had identifiable environmental preferences that influence their spatial distribution in abundance, body size, and allometric growth.

4.
Front Physiol ; 11: 760, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32760287

RESUMO

The common octopus, Octopus vulgaris, has a short life cycle, growing rapidly to maturity, spawning once, and characterized by an asynchronic oocyte development and a synchronic ovulation dying after breeding. This species has a protein and amino acid metabolism and it is usually defined as an income breeder. However, most biochemical studies lack an examination of the whole reproductive cycle, in particular the spawning process. We here studied the biochemical changes and determined the energy strategy along reproduction in female O. vulgaris, and found that proteins were the main energy reserve, primarily located in the body muscle when sexually maturing and decreasing during breeding. Lipids were also an important source of energy in the ovary and digestive gland and decreased during breeding too. By contrast, glycogen had a minor contribution to the energy content and was the unique compound that increased in spawning and post-spawning females. Additionally, the most abundant fatty acids (FA) in all tissues were 16:0, 18:0, 20:1n9, 20:4n6 (ARA), 20:5n3 (EPA) and 22:6n3 (DHA), with a clear predominance of long-chain polyunsaturated FA. The FA profile of mature ovaries was compared with other life stages finding similitudes with eggs, hatchlings and juveniles but considerable differences with paralarvae which showed higher DHA/ARA and EPA/ARA ratios. Therefore, we found important biochemical changes along the reproductive cycle that determined the energetic signature in each tissue, though no significant energy trade-offs between tissues were found, suggesting that, on the one hand, female O. vulgaris obtained energy directly from food accumulated simultaneously in the somatic and reproductive tissues during sexual maturation. However, an energy reallocation from somatic to reproductive growth would occur once vitellogenesis has started, so that the rate at which body growths would decrease in favor of ovary growth. On the other hand, during breeding, a general decrease in the energy content occurred in all tissues, so that the ovary would be responsible for the spawning success, whereas muscle tissues and digestive gland would independently supply the energy needed for the body maintenance safeguarding the female survival needed for the maternal care.

5.
OMICS ; 9(2): 209-17, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-15969651

RESUMO

It is of central interest in biology to understand how gene activity networks are coordinated and integrated in the cell. Within the field of genomics, microarray technologies have become a powerful technique for monitoring simultaneously the expression patterns of thousands of genes under different sets of conditions. A main task now is to propose analytical methods that can suggest which groups of genes are activated by similar conditions. We review several techniques based on self-organizing map and clustering algorithms but implemented through a network of units controlled by biologically inspired functions (see Table 1). The computer tool, named NBIA, permits a categorization that generates a set of gene groups with coordinated expression patterns.


Assuntos
Perfilação da Expressão Gênica/estatística & dados numéricos , Algoritmos , Análise por Conglomerados , Interpretação Estatística de Dados , Redes Neurais de Computação , Análise de Sequência com Séries de Oligonucleotídeos/estatística & dados numéricos , Reconhecimento Automatizado de Padrão/estatística & dados numéricos , Software , Interface Usuário-Computador
6.
Arch Med Res ; 33(3): 245-9, 2002.
Artigo em Inglês | MEDLINE | ID: mdl-12031628

RESUMO

Diverse forms of pathologies can be derived from the lack of flexibility in tissues and the absence of required concentrations of certain types of proteins (e.g., amelogenesis imperfecta). beta-spirals using canonical proline-nucleated beta-turns in diverse proteins allow for vital functions including structural (mucin and amelogenin), respiratory (elastin), muscular (titin), and that of genetic expression (RNA polymerase II). These confer particular physical and chemical properties to proteins and therefore to the tissues in which they are found, while the pervasive presence of tandem repeats in the genome sequence indicates their importance. This paper discusses the general biomedical relevance of this structure, focusing on several proteins found in humans.


Assuntos
Conformação Proteica , Sequências de Repetição em Tandem , Proteínas/química , Proteínas/genética
7.
Biosystems ; 68(2-3): 171-85, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-12595116

RESUMO

The theory of behaviour-based systems (or autonomous agents) constitutes a useful approach for the modelling of intracellular signalling networks. In this sense, a cell can be seen as an adaptive autonomous agent or as a society of such agents, where each can exhibit a particular behaviour depending on its cognitive capabilities. We present an intracellular signalling model obtained by integrating several computational techniques into an agent-based paradigm. Cellulat, the model, takes into account two essential aspects of the intracellular signalling networks: (1) cognitive capacities, which are modelled as the agent abilities to interact with the surrounding medium and (2) a spatial organisation, this last obtained using a shared data structure through which the agents communicate between them. We propose a methodology for the modelling of intracellular signalling pathway using Cellulat and we discuss the goal of a virtual laboratory based on our model and presently under development.


Assuntos
Transdução de Sinais , Comunicação Celular , Receptores ErbB/metabolismo
8.
Ecol Evol ; 2(9): 2192-203, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23139878

RESUMO

Atlantic salmon populations are reported to be declining throughout its range, raising major management concerns. Variation in adult fish abundance may be due to variation in survival, growth, and timing of life history decisions. Given the complex life history, utilizing highly divergent habitats, the reasons for declines may be multiple and difficult to disentangle. Using recreational angling data of two sea age groups, one-sea-winter (1SW) and two-sea-winter (2SW) fish originated from the same smolt year class, we show that sea age at maturity of the returns has increased in 59 Norwegian rivers over the cohorts 1991-2005. By means of linear mixed-effects models we found that the proportion of 1SW fish spawning in Norway has decreased concomitant with the increasing sea surface temperature experienced by the fish in autumn during their first year at sea. Furthermore, the decrease in the proportion of 1SW fish was influenced by freshwater conditions as measured by water discharge during summer months 1 year ahead of seaward migration. These results suggest that part of the variability in age at maturity can be explained by the large-scale changes occurring in the north-eastern Atlantic pelagic food web affecting postsmolt growth, and by differences in river conditions influencing presmolt growth rate and later upstream migration.

9.
Rev. estomatol. Hered ; 27(3): 176-179, jul.-set. 2017. tab
Artigo em Espanhol | LILACS | ID: biblio-991186

RESUMO

Objetivos: Determinar la presencia y concentración de los metales plomo, cadmio y cromo migrados desde el limpiador lingual "Alitest" en saliva artificial, y estimar la exposición oral a estas sustancias. Material y métodos: Diseño pre-experimental y analítico, para cuantificar las sustancias que son liberadas desde el limpiador lingual al contacto con saliva artificial. Los metales fueron analizados por AAS. Se estimaron los valores de exposición por ingesta oral que fueron comparados con valores de ingesta diaria tolerable para cada grupo etario. Resultados: Se cuantificó la migración de cadmio y cromo en concentraciones promedio de 0.008mg/L y 0.437 mg/L, respectivamente. La concentración de plomo estuvo por debajo de los niveles detectables utilizando el método. A partir de estos valores se estimó la ingesta oral para cada grupo etario y se comparó con el valor provisional de ingesta mensual tolerable (PTMI) o Dosis de Referencia (RfD). Conclusiones: Las sustancias se cuantificaron en concentraciones normales, que no excedieron los valores máximos recomendados.


Objectives: To determine the concentration of heavy metals cadmium and chromium leached from the tongue cleaner "Alitest" into artificial saliva and to assess oral exposure of these substances. Material and methods: Analytical pre-experimental design, to determine the amount of those substances released from the tongue cleaner onto artificial saliva and to quantified them by AAS. Assessment of exposure from oral intake values and comparison with the Provisional Tolerable Monthly Intake (PTMI) or Reference Dose (RfD) values. Results: Cadmium and chromium leachated into artificial saliva were quantified in concentrations of 0.008mg/L and 0.437 mg/L, respectively. Lead concentration was under detectable levels using the method. These values were used to estimate the oral intake for each age group and were compared to PTMI or RfD values. Conclusions: The substances were found in normal concentrations, none exceeding the maximum values of PTMI or RfD.

10.
PLoS One ; 6(8): e24005, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21897867

RESUMO

Many Atlantic salmon, Salmo salar, populations are decreasing throughout the species' distributional range probably due to several factors acting in concert. A number of studies have documented the influence of freshwater and ocean conditions, climate variability and human impacts resulting from impoundment and aquaculture. However, most previous research has focused on analyzing single or only a few populations, and quantified isolated effects rather than handling multiple factors in conjunction. By using a multi-river mixed-effects model we estimated the effects of oceanic and river conditions, as well as human impacts, on year-to-year and between-river variability across 60 time series of recreational catch of one-sea-winter salmon (grilse) from Norwegian rivers over 29 years (1979-2007). Warm coastal temperatures at the time of smolt entrance into the sea and increased water discharge during upstream migration of mature fish were associated with higher rod catches of grilse. When hydropower stations were present in the course of the river systems the strength of the relationship with runoff was reduced. Catches of grilse in the river increased significantly following the reduction of the harvesting of this life-stage at sea. However, an average decreasing temporal trend was still detected and appeared to be stronger in the presence of salmon farms on the migration route of smolts in coastal/fjord areas. These results suggest that both ocean and freshwater conditions in conjunction with various human impacts contribute to shape interannual fluctuations and between-river variability of wild Atlantic salmon in Norwegian rivers. Current global change altering coastal temperature and water flow patterns might have implications for future grilse catches, moreover, positioning of aquaculture facilities as well as the implementation of hydropower schemes or other encroachments should be made with care when implementing management actions and searching for solutions to conserve this species.


Assuntos
Atividades Humanas/estatística & dados numéricos , Rios , Salmo salar , Estações do Ano , Animais , Noruega , Oceanos e Mares , Densidade Demográfica
12.
In Silico Biol ; 2(4): 453-60, 2002.
Artigo em Inglês | MEDLINE | ID: mdl-12611625

RESUMO

Ras is a protein related to cancer development. It is a convergence point for different signal transduction pathways that allow the cell to respond to external stimuli with different cell functions like growth, division, death, etc. In this paper, we analyze the signal pathways generated by different Ras effectors (Raf, RalGDS and PI3K), and the pathway relating Ras to the cell cycle control. We show that the interaction among different elements of these pathways induces a topologic structure in the set of elements. We discuss properties of this topology and give an algorithm to build it. The application of topological concepts makes easier the interaction analysis. Using a computational algorithm, we can create isolated, independently manageable sub-groups. Then we construct their hierarchical structure. The procedure allows us to visualize groups of elements related to the Ras effectors involved in cell growth, the elements involved in the cytoskeleton regulation, and the elements related to the cell cycle control. Thus the division in sub-groups does not only make easier the analysis, but it also provides a biologically meaningful subdivision.


Assuntos
Transdução de Sinais , Proteínas ras/metabolismo , Proteínas ras/fisiologia , Algoritmos , Animais , Modelos Biológicos , Modelos Teóricos , Software
14.
Acta méd. colomb ; 28(3): 108-111, mayo-jun. 2003. tab, graf
Artigo em Espanhol | LILACS | ID: lil-358207

RESUMO

Objetivo: establecer la frecuencia de infección tuberculosa en el personal de la salud comparativamente con el personal no expuesto. Diseño: estudio de prevalencia analítico el cual compara un grupo de enfermeras en contacto con pacientes con tuberculosis contra un grupo de trabajadores no expuestos. Marco de referencia: enfermeras de los servicios de medicina interna y urgencias del Hospital General de Medellín (hospital de tercer nivel) con un grupo de empleados de una fábrica de tintas (Tintas S.A.). Participantes: se aplicó tuberculina a las enfermeras del servicio de medicina interna y urgencias del Hospital General de Medellín (HGM), n= 45 y empleados de una fábrica de tintas n = 54 que aceptaron participar en el estudio. Mediciones: se aplicó tuberculina tipo APLISOL® 5TU por la técnica de Mantoux tomando como valor positivo > 10 mm de induración. Se determinó la relación con la vacunación previa de BCG y el tiempo de exposición laboral en el grupo de trabajadores de la salud. Resultados: de las 45 enfermeras que se les aplicó tuberculina, el 51,1 por ciento resultó positivo y de los 54 empleados de la fábrica el 16,7 por ciento; siendo el riesgo 3,15 veces mayor en el grupo expuesto. p = < 0,001. No se halló relación con el tiempo de exposición P = 0,641 ni con la aplicación previa de BCG. Conclusión: el trabajador de la salud que ve pacientes con tuberculosis tiene un riesgo 3,15 veces mayor de ser infectado por el bacilo tuberculoso que la población general. Resaltamos la importancia de reforzar las medidas de prevención dentro de los hospitales y la aplicación de tuberculina en los trabajadores para conocer su estado de infección.


Assuntos
Pessoal de Saúde , Riscos Ocupacionais , Fatores de Risco , Tuberculose
15.
J. bras. ginecol ; 97(1/2): 39-42, jan.-fev. 1987. ilus
Artigo em Português | LILACS | ID: lil-40473

RESUMO

É apresentado um caso de uma paciente de 33 anos de idade, com história de amenorréia e galactorréia, com hiperprolactinemia. Radiologicamente evidenciou-se presença de tumor hipofisário (macroprolactinoma). Ao exame anatomopatológico de esvaziamento selar e para-selar diagnosticou-se carcinoma hipofisário. Analisam-se as controvérsias e dificuldades diagnósticas dessa rara entidade nosológica


Assuntos
Adulto , Humanos , Feminino , Neoplasias Hipofisárias/diagnóstico , Neoplasias Hipofisárias/patologia
16.
Rev. cuba. ortod ; 5(1): 32-46, ene.-jun.1990.
Artigo em Espanhol | LILACS | ID: lil-93448
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA