Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 48
Filtrar
1.
Radiologia ; 55(2): 142-7, 2013.
Artigo em Espanhol | MEDLINE | ID: mdl-22015223

RESUMO

OBJECTIVE: To determine whether the introduction of digital mammography in breast cancer screening has resulted in changes in the detection and management of microcalcifications. MATERIAL AND METHODS: We retrospectively studied the performance indicators of our breast cancer screening program that are related to the diagnosis of microcalcifications (rates of recall and recommendation of intermediate follow-up after screening, rate of indication of invasive procedures for microcalcifications and their positive predictive value, detection rate for microcalcifications, and number of ductal carcinomas in situ (DCIS) diagnosed). We compared the results obtained using direct digital mammography (september 2008-august 2009) with those obtained using analog mammography (September 2006-August 2007). STATISTICAL ANALYSIS: Chi-square test and measures of association. RESULTS: We found that using digital mammography led to significant increases in the recall rate (from 50.8 to 64‰), in the rate of intermediate follow-up after screening (from 9.41 to 18.7‰), in the rate of indication for invasive procedures (from 1.88 to 3.01‰), in the cancers detected through microcalcifications (from 0.86 to 1.36‰), and in the number of DCIS diagnosed. CONCLUSION: Direct digital mammography has improved the detection of microcalcifications, increasing the number of DCIS diagnosed without decreasing the positive predictive value of the invasive procedures indicated for microcalcifications. However, direct digital mammography has had a negative effect by increasing the recall rate and indication for short-term follow-up, possibly due to the difficulty of comparing the findings with those of earlier analog mammograms.


Assuntos
Doenças Mamárias/diagnóstico por imagem , Neoplasias da Mama/diagnóstico por imagem , Calcinose/diagnóstico por imagem , Carcinoma Intraductal não Infiltrante/diagnóstico por imagem , Detecção Precoce de Câncer , Mamografia/métodos , Intensificação de Imagem Radiográfica , Doenças Mamárias/terapia , Neoplasias da Mama/complicações , Calcinose/complicações , Calcinose/terapia , Carcinoma Intraductal não Infiltrante/complicações , Feminino , Humanos , Estudos Retrospectivos
2.
Mar Pollut Bull ; 174: 113299, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35090282

RESUMO

The accelerated discard and mismanagement of human-made products are resulting in the continued input of litter into the oceans. Models and field observations show how floating litter can accumulate in remote areas throughout the global ocean, but far less is known about the non-floating litter fraction. Seagrass meadows play an important role in the sediment and natural-debris dynamics, and likely also in the storage and processing of non-floating litter. In this work, non-floating litter was studied across six Posidonia oceanica meadows. Litter accumulated mainly around the landside edge of the meadow. The outer margin of the edge predominantly trapped macro-litter, whilst microplastics accumulated mainly along the inner margin. On average, macro-litter concentrations increased 3-fold after heavy rainfall. Retention of non-floating litter by coastal meadows facilitates the recurrent landward-seaward conveyance of the easily-transportable litter (mainly plastic items) and its fragmentation before it is buried or transferred to deeper areas.


Assuntos
Alismatales , Plásticos , Humanos , Oceanos e Mares
3.
Sci Rep ; 12(1): 6807, 2022 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-35474343

RESUMO

The factors that cause a preterm birth (PTB) are not completely understood up to date. Moreover, PTB is more common in pregnancies achieved by in-vitro fertilization (IVF) than in spontaneous pregnancies. Our aim was to compare the composition of vaginal microbiome at 12 weeks of gestation between women who conceived naturally or through IVF in order to study whether IVF PTB-risk could be related to vaginal microbiome composition. We performed an observational, prospective and multicentre study among two public hospitals and a fertility private clinic in Spain. Vaginal swabs from 64 pregnant women at 12 weeks of gestation were collected to analyse the microbiome composition by sequencing the V3-V4 region of the 16S rRNA. Our results showed that the vaginal microbiome signature at 12 weeks of pregnancy was different from women who conceived naturally or through IVF. The beta diversity and the genus composition were different between both cohorts. Gardnerella, Neisseria, Prevotella, and Staphylococcus genus were enriched genus in the vaginal microbiome from the IVF group, allowing us to create a balance model to predict both cohorts. Moreover, at species level the L. iners abundance was higher and L. gasseri was lower in the IVF group. As a conclusion, our findings were consistent with a proposed framework in which IVF pregnancy are related to risk for preterm birth (PTB) suggesting vaginal microbiome could be the reason to the relation between IVF pregnancy and risk for PTB.


Assuntos
Microbiota , Nascimento Prematuro , Feminino , Fertilização in vitro/efeitos adversos , Humanos , Recém-Nascido , Microbiota/genética , Gravidez , Nascimento Prematuro/epidemiologia , Estudos Prospectivos , RNA Ribossômico 16S/genética
4.
Mar Pollut Bull ; 172: 112802, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34371343

RESUMO

Microplastic deposition in marine sediments is a geographically widespread problem. This study examines microplastics in intertidal and subtidal sediments at 87 locations in habitats designated as Special Areas of Conservation (SACs) and Special Protection Areas (SPAs) on the coastline of Ireland. Established methodological approaches including, organic matter digestion, density separation, particle extraction and polymer identification were applied. Microplastic abundance was closely related with distance from known sources and concentrations were greater in intertidal as opposed to subtidal sediments. Colourless, polyethylene fibres and polypropylene fragments were the most abundant MP recorded and finer grained sediments were shown to entrap more MPs than coarser sediments. The results demonstrate that an understanding of potential sources of pollution, sediment type and hydrodynamic conditions are very important in terms of MP abundance and distribution in marine sediments and also in terms of effective waste management strategies and policy aimed at reducing the global plastics problem.


Assuntos
Microplásticos , Poluentes Químicos da Água , Monitoramento Ambiental , Sedimentos Geológicos , Plásticos , Poluentes Químicos da Água/análise
5.
Somatosens Mot Res ; 27(3): 111-20, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20722492

RESUMO

Rodent whisking behavior generates two types of neural signals: one produced by whisker contact with objects; the other by movements in air. While kinematic signals generated by contact reliably activate neurons at all levels of the trigeminal neuraxis, the extent to which the kinematics of whisking in air are reliably encoded at each level remains unclear. Previously, we showed that the responses of trigeminal ganglion (TG) neurons in awake, head-fixed rats are correlated with whisking kinematic parameters, but that individual neurons may differ substantially in the reliability of their kinematic encoding. Here, we extend that analysis to neurons in the ventral posterior medial (VPM) nucleus. Three possible coding strategies were examined: (1) firing rate across an entire movement; (2) the probability of individual spikes as a function of the instantaneous movement trajectory; and (3) the coherence between spikes and whisking. While VPM neurons were clearly responsive to variations in whisker kinematics during whisking in air, the encoding of whisker kinematics by VPM neurons was less consistent than that of TG neurons. Furthermore, we found that, in VPM as in TG, movement direction is an important determinant of unit responsiveness during whisking in air.


Assuntos
Neurônios/fisiologia , Núcleos Ventrais do Tálamo/fisiologia , Vibrissas/fisiologia , Animais , Eletrofisiologia , Feminino , Estimulação Física , Ratos , Ratos Sprague-Dawley , Estatísticas não Paramétricas
6.
Sci Total Environ ; 407(3): 999-1009, 2009 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-19027934

RESUMO

Ambient concentrations of volatile organic compounds (VOC) and nitrogen dioxide (NO2) were measured by means of passive sampling at 40 sampling points in a medium-size city in Northern Spain, from June 2006 to June 2007. VOC and NO2 samplers were analysed by thermal desorption followed by gas chromatography/mass-selective detector and by visible spectrophotometry, respectively. Mean concentrations of benzene, toluene, ethylbenzene, xylenes, propylbenzene, trimethylbenzenes, and NO(2) were 2.84, 13.26, 2.15, 6.01, 0.59, 1.32 and 23.17 microg m(-3) respectively, and found to be highly correlated. Their spatial distribution showed high differences in small distances and pointed to traffic as the main emission source of these compounds. The lowest levels of VOC and NO2 occurred during summer, owing to the increase in solar radiation and to lower traffic densities. Mean concentrations of benzene and NO2 exceeded the European limits at some of the monitored points.


Assuntos
Ar/análise , Dióxido de Nitrogênio/análise , Compostos Orgânicos Voláteis/análise , Poluição do Ar/análise , Benzeno/análise , Derivados de Benzeno/análise , Ritmo Circadiano , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Estações do Ano , Espanha , Tolueno/análise , População Urbana , Emissões de Veículos/análise , Xilenos/análise
7.
J Mech Behav Biomed Mater ; 91: 99-108, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30553208

RESUMO

Micro-surgical instruments are a new application for mesoscale ceramics formed using the lost mold-rapid infiltration forming (LM-RIF) process. Instrument strength and reliability are the foremost concerns for this sensitive application. It is hypothesized that increasing grain size can improve the damage tolerance of the parts associated with the transformation toughening in the 3Y-TZP material, while retaining high strength. In this work, mesoscale bend bars (314 × 22 × 18 µm) of 3Y-TZP fabricated using the LM-RIF process were heat treated at 1400 °C for 1 h, 8 h, or 16 h, respectively, to obtain samples with different grain sizes. Strength tests were performed under three-point bending and results were evaluated using Weibull statistics. Fractographic and confocal Raman spectroscopic analyses were carried out to interpret the data. Experimental findings showed that the characteristic strength decreased with increasing grain size contrary to the damage tolerance hypothesis. An Orowan-Petch model was recalled to correlate the strength with the flaw size to grain size ratio. At fine grain sizes the strength was controlled by the flaws introduced by the LM-RIF process, whereas at large grain sizes the strength become more grain size controlled. Although larger-grained samples did have a higher propensity to transform, and thus increase toughening, exaggerated grain growth in some of the specimens tested caused an additional flaw population which led to an overall lower strength. Finally, based on the experimental observations and fracture mechanics considerations, we believe that an upper bound of ∼2.5 GPa exists for the strength of mesoscale as-fabricated 3Y-TZP ceramic parts.


Assuntos
Cerâmica/química , Fenômenos Mecânicos , Equipamentos Cirúrgicos , Zircônio/química , Teste de Materiais
8.
Rev Esp Quimioter ; 32(4): 296-302, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31232572

RESUMO

OBJECTIVE: The efficacy of ledipasvir/sofosbuvir (LDV/SOF) have been demonstrated in randomized controlled trials, however,there is an unmet need for real-world effectiveness data. It is important to gather data regarding potential predictors of treatment failure with (LDV/SOF). Predictors of sustained virologic response (SVR) to all-oral HCV regimens can inform nuanced treatment decisions. The objectives of this study were to evaluate the effectiveness of LDV/SOF, SVR12 as main endpoint and SVR24 as second endpoint, and identify predictors of treatment failure. METHODS: Retrospective and observational study carried out from April 2015 to January 2016. Inclusion criteria: patients with HCV infection treated with LDV/SOF for 12 weeks during study period. The patients that were treated during 24 weeks were excluded as well as those treated with peg-interferon. Binary logistic regression was used to predict what variable was associated with treatment failure. RESULTS: A total of 122 patients were analyzed achieving SVR12 91.80% (112/122) of them. The patients with HCV genotype (GT) 1a or GT1b or GT4 achieved SVR12. Only one pre-treated non-cirrhotic HCV GT1 patients relapsed to treatment. The lowest SVR12 were obtained for GT3, 43.75%, (7/16). Everybody that got SVR12 achieved SVR24. None of the variables analyzed significantly influenced the SVR12, except GT (p=0.001). Almost all the relapses occurred in GT3. CONCLUSIONS: LDV/SOF combination has been very effective to treat GT1 and GT4 infected patients, however, has constituted a suboptimal therapeutic option for those patients infected with GT3, regardless of the rest of the variables analyzed.


Assuntos
Antivirais/administração & dosagem , Benzimidazóis/administração & dosagem , Fluorenos/administração & dosagem , Hepacivirus/genética , Hepatite C/tratamento farmacológico , Sofosbuvir/administração & dosagem , Resposta Viral Sustentada , Esquema de Medicação , Quimioterapia Combinada , Feminino , Genótipo , Hepatite C/virologia , Humanos , Cirrose Hepática/patologia , Masculino , Pessoa de Meia-Idade , Recidiva , Análise de Regressão , Estudos Retrospectivos , Falha de Tratamento
9.
Sci Total Environ ; 404(1): 18-25, 2008 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-18656247

RESUMO

This study examines the exposure level of passengers and drivers to VOC in public buses in a medium-size metropolitan area (Northern Spain). In-vehicle monitoring was performed on different routes, on peak and non-peak hours, during January and February 2007. A total of 112 air samples were collected onto adsorbent tubes and analysed by thermal desorption (TD) and gas chromatography/mass selective detector (GC/MSD) technique. Statistical differences were found among route to route concentrations, with those routes with major prevalence in the commercial area of the city displaying higher values; differences between peak and non-peak hours were also observed. A decrease in VOC concentrations was also registered during the weekend. BTEX ratios were estimated and found to be related to traffic emissions and similar for all the surveyed routes. Correlations confirmed traffic as the main emission source for BTEX and trimethylbenzene, their concentrations being highly associated to changes in meteorological conditions.


Assuntos
Poluentes Atmosféricos/análise , Exposição Ambiental , Hidrocarbonetos/análise , Material Particulado/análise , Cromatografia Gasosa , Monitoramento Ambiental , Humanos , Exposição por Inalação , Espectrometria de Massas , Espanha , Meios de Transporte , População Urbana
10.
Eur J Obstet Gynecol Reprod Biol ; 135(1): 73-5, 2007 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17537567

RESUMO

OBJECTIVE: To know the contraceptive use and trends in the Spanish female population. STUDY DESIGN: Since 1997, we have conducted a survey every 2 years on the use of contraceptive methods among a representative sample of Spanish women of childbearing potential (15-49 years). RESULTS: In the period 1997-2003, the percentage of use of contraceptive methods in Spain rose from 55.6% to 71.2%. The most commonly used method was the condom (21% in 1997, 21.9% in 1999, 29.5% in 2001 and 35.7% in 2003), followed by the contraceptive pill (14.2%, 16.5%, 19.2% and 18.3%, respectively). Male or female sterilization remained stable with percentages of use of 5-7%. IUDs are used by about 5% of women. CONCLUSIONS: The use of contraceptive methods among Spanish women of childbearing potential generally fits quite well the patterns found in other developed countries, and we observed a trend towards increased use of effective methods.


Assuntos
Comportamento Contraceptivo/estatística & dados numéricos , Anticoncepção/estatística & dados numéricos , Adolescente , Adulto , Anticoncepção/tendências , Comportamento Contraceptivo/tendências , Estudos Transversais , Feminino , Inquéritos Epidemiológicos , Humanos , Pessoa de Meia-Idade , Espanha
11.
Sci Total Environ ; 370(1): 157-67, 2006 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-16899278

RESUMO

Ambient concentrations of volatile organic compounds (VOCs) were measured at 40 rural sampling points in Navarre (northern Spain). Air samples were collected by means of sorbent passive sampling and analyzed by thermal desorption (TD) and gas chromatography/mass-selective detector (GC/MSD). A total of 140 VOCs were identified during the study, which was carried out between May to October 2004 for a total of a 10 biweekly sampling campaigns. Concentrations of benzene, toluene, ethylbenzene, m/p-xylenes, o-xylene (BTEX) and 1,3,5-trimethylbenzene were determined in order to investigate their temporal and spatial distributions. Geostatistical analysis pointed to traffic as the main emission source of these compounds. Supporting this idea, BTEX and nitrogen oxides concentrations were found to be highly significantly correlated (r = 0.495, P = 0.001), whereas a strong negative correlation between BTEX and ozone was also observed (r = -0.355, P = 0.025). The concentrations for the BTEX group were similar to the values that have been previously reported for other rural areas.


Assuntos
Poluentes Atmosféricos/análise , Ar/análise , Monitoramento Ambiental , Compostos Orgânicos/análise , Ar/normas , Saúde da População Rural , Espanha , Volatilização
12.
An Med Interna ; 23(9): 435-7, 2006 Sep.
Artigo em Espanhol | MEDLINE | ID: mdl-17096607

RESUMO

The acute pseudobstruction of the colon or Ogilvie's syndrome is a infrequent pathology of acute or subacute evolution, that is associated to different clinical or surgical pathologies, and whose pathophysiology continues to be unknown. The treatment begins with general measures and if these are not effective, with the surgical decompression of colon to avoid the most serious complication, and frequently that is perforation of the cecum. We present a case of an acute and idiopathic dilatation of colon in an adult man who entered by an episode of acute respiratory insufficiency, and that was solved with preservative medical treatment.


Assuntos
Pseudo-Obstrução do Colo/diagnóstico , Abdome Agudo/etiologia , Doença Aguda , Idoso de 80 Anos ou mais , Pseudo-Obstrução do Colo/complicações , Pseudo-Obstrução do Colo/terapia , Humanos , Masculino , Doença Pulmonar Obstrutiva Crônica/complicações , Insuficiência Respiratória/complicações
13.
Rev Calid Asist ; 31(4): 196-203, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26869298

RESUMO

OBJECTIVE: To update the metric properties of a perceived quality questionnaire for patients admitted to hospital medical departments, to determine the level of patient satisfaction achieved, and to identify the variables which predict satisfaction. METHODS: Self-administered questionnaire completed at home following patient discharge, using a questionnaire prepared by the authors on a sample of 7207 users of medical departments in 9 public hospitals during the years 2006-2009. A principal component analysis with varimax rotation was performed. Reliability was assessed using internal consistency coefficient. An analysis was made of the compliance with each indicator reported by respondents. A logistic regression analysis was performed to determine the perceived quality dimensions which predicted overall patient satisfaction. RESULTS: The results of the reliability analysis indicated good coefficients for interpersonal manner (0.94) and professional competence (0.85) dimensions, and moderate values for the other dimensions (comfort 0.55, information 0.38, and organisation 0.37). Factor analyses showed single factors in each of the perceived quality dimensions, with a percentage of explained variance greater than 35% for information, interpersonal manner, professional competence, and comfort, and less than 30% for organisation. The dimensions which predicted satisfaction were interpersonal manner of healthcare staff, professional competence, and information. CONCLUSIONS: The metric properties of the questionnaire used have been updated, yielding a valid and reliable questionnaire for assessing patient satisfaction in quality management programmes, both for internal purposes and for conducting external comparisons. A positive relationship was obtained between the level of patient satisfaction and level of professional competence, interpersonal manner of healthcare staff, and information received.


Assuntos
Departamentos Hospitalares , Satisfação do Paciente , Humanos , Cooperação do Paciente , Reprodutibilidade dos Testes , Inquéritos e Questionários
14.
J Neurosci ; 21(14): 5374-80, 2001 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-11438614

RESUMO

Even in the absence of explicit stimulation, rats emit patterns of rhythmic whisking movements. Because of their stereotyped nature and their persistence after sensory denervation and cortical ablation, whisking movements have been assumed to reflect the output of a central pattern generator (CPG). However, identification of a movement pattern as the product of a CPG requires evidence that its generation, patterning, and coordination are independent of sensory input. To provide such evidence, we used optoelectronic instrumentation to obtain high-resolution records of the movement trajectories of individual whiskers in rats whose heads were fixed to isolate their exploratory whisking from exafferent inputs. Unconditioned whisking patterns were quantitatively characterized by a biometric analysis of the kinematics, rhythmicity, and coordination of bilaterally homologous vibrissa movements. Unilateral and bilateral sectioning of the infraorbital nerve, which innervates the whiskers, was then performed to block reafferent inputs generated by the animal's own whisking movements. Unilateral sectioning of the nerve has no effect on whisking kinematics but is followed by a significant but relatively transient bilateral increase in whisking frequency. However, bilateral deafferentation, when performed in a single-stage procedure, does not disrupt the generation, patterning, or bilateral coordination of whisking patterns in the rat. These findings provide strong behavioral evidence for a whisking CPG and are discussed in relation to its possible location and properties.


Assuntos
Vias Aferentes/fisiologia , Comportamento Animal/fisiologia , Instinto , Comportamento Estereotipado/fisiologia , Vibrissas/inervação , Animais , Axotomia , Fenômenos Biomecânicos , Feminino , Análise de Fourier , Lateralidade Funcional/fisiologia , Nervo Maxilar/fisiologia , Movimento/fisiologia , Periodicidade , Ratos , Ratos Long-Evans , Nervo Trigêmeo/fisiologia , Vibrissas/fisiologia
15.
J Neurosci Methods ; 83(2): 89-96, 1998 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-9765121

RESUMO

We describe two systems for the real-time recording and display of individual vibrissa movements in head-fixed rats. Both systems utilize high-speed, linear image sensors, each composed of an array of light sensitive elements (CCDs). Uniform illumination of the array generates a constant baseline voltage in each element. The shadow produced by the movement of a whisker interposed between the light source and the sensors produces a voltage shift in a subset of elements. The successive position of the shift is linearly related to the momentary whisker position. Associated software/hardware scans the array at regular intervals to identify the successive positions of voltages above a preset threshold and outputs the data to a microprocessor for computation of the whisker movement trajectory. In both systems, movements of a single whisker may be monitored 'on-line' with high spatial and temporal resolution; in one case with, in the other without the presence of neighboring whiskers. Optoelectronic monitoring facilitates rapid and efficient (computer-assisted) acquisition and analysis of data on rodent whisking behavior.


Assuntos
Tecnologia de Fibra Óptica/instrumentação , Tecnologia de Fibra Óptica/métodos , Movimento/fisiologia , Vibrissas/fisiologia , Animais , Comportamento Animal/fisiologia , Feminino , Cabeça/fisiologia , Ratos , Ratos Long-Evans , Ratos Sprague-Dawley
16.
Behav Brain Res ; 99(2): 181-9, 1999 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10512584

RESUMO

To clarify the contribution of peripheral trigeminal input to the control of pecking behavior we examined head and jaw movement kinematics and peck localization in pigeons with surgical section of trigeminal nerves providing somatosensory input to the beak. Conditioning procedures were used to bring the pecking/grasping components of pecking under the control of a visual target. Conditioned head and jaw movements were monitored 'on-line' using movement transducers and terminal peck location was recorded using 'touch-screen' technology. The periodic delivery of a food reinforcer provided repeated opportunities to monitor the kinematics of ingestive pecks. Deafferentation produced deficits in mandibulation during ingestive pecking and in the coordination of head and jaw movements during conditioned pecking. These results are attributed to disruptions in trigeminal feedback and feedforward mechanisms, respectively. In contrast with previous studies, deafferentation did not impair the precision of peck localization. Possible reasons for the absence of localization deficits are presented. The results are discussed in relation to the role of peripheral inputs in the control of prehensile movements.


Assuntos
Condicionamento Operante/fisiologia , Neurônios Aferentes/fisiologia , Nervo Trigêmeo/fisiologia , Animais , Comportamento Animal/fisiologia , Fenômenos Biomecânicos , Columbidae , Denervação , Movimentos da Cabeça/fisiologia , Arcada Osseodentária/fisiologia , Transdução de Sinais/fisiologia , Nervo Trigêmeo/citologia
17.
Behav Brain Res ; 91(1-2): 173-84, 1998 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-9578450

RESUMO

Like human prehensile behavior, the pigeon's ingestive pecking response is elicited by visual stimuli conveying information about the location and size of the target. This information is used to generate localized ingestive pecks whose gapes are amplitude-scaled to seed size, prior to contact. We employed high-resolution, 'real-time' monitoring of head acceleration, jaw movements and terminal peck location to examine the kinematics, coordination and stimulus control of conditioned pecking. Conditioning procedures were used to bring pecking under the control of visual targets whose stimulus properties (size, location) were independently varied, while simultaneously monitoring pecking response parameters. Stimulus control of the transport component (peck localization) is extremely precise, even in the absence of a specific localization-dependent reinforcement contingency. Subjects also showed amplitude-scaling of gape size to the size of a visual target, but over a more restricted range than shown to food pellets of comparable sizes. Comparison of the kinematic profiles of conditioned and ingestive pecks suggests that conditioned pecking is functionally analogous to human 'pointing' rather than 'grasping' behavior.


Assuntos
Condicionamento Operante/fisiologia , Força da Mão/fisiologia , Movimentos da Cabeça/fisiologia , Desempenho Psicomotor/fisiologia , Animais , Columbidae , Comportamento Exploratório/fisiologia , Arcada Osseodentária/fisiologia , Estimulação Luminosa , Reforço Psicológico , Percepção Espacial/fisiologia
18.
Behav Brain Res ; 35(1): 55-61, 1989 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-2803544

RESUMO

During the grasping and manipulation phases of the pigeon's ingestive pecking behavior, jaw opening movements are scaled to the size of the target (food) object. To assess the contribution of beak mechanoreceptor afferents to the control of scaling we examined the effects of bilateral trigeminal deafferentation upon the kinematics of jaw opening trajectories. Deafferented subjects exhibited both a transient reduction in the accuracy of peck localization and a more persistent deficit in the effectiveness of their ingestive pecking response. However, they continued to exhibit the same classes of jaw movement described for the normal pigeon. The functional relation between target size and gape remained unchanged after deafferentation as did the relationships among kinematic variables controlling jaw opening. However, deafferentation produced small but significant increase in the absolute values of peak gape for both grasping and mandibulation which reflects an increase in peak opening velocity. The results are discussed in relation to the problem of sensory control of rapid targeted movements.


Assuntos
Bico/inervação , Columbidae/fisiologia , Comportamento Alimentar/fisiologia , Músculos da Mastigação/inervação , Mecanorreceptores/fisiologia , Nervo Trigêmeo/fisiologia , Vias Aferentes/fisiologia , Animais , Arcada Osseodentária/inervação , Cinestesia/fisiologia
19.
J Chromatogr A ; 917(1-2): 135-45, 2001 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-11403465

RESUMO

A fast preparative two-step chromatographic method for purification of B-phycoerythrin from Porphyridium cruentum is described. This biliprotein was homogeneous as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis yielding three closely migrating bands corresponding to its three subunits. Baseline separation of its alpha-, beta- and gamma-subunits was achieved by a reversed-phase HPLC gradient semipreparative method with a C4 large-pore column and a solvent system consisting of 0.05% trifluoroacetic acid (TFA) in water and 0.05% TFA in acetonitrile. B-Phycoerythrin in different aggregation states and its subunits have been spectroscopically characterized. Hexameric B-phycoerythrin has similar secondary and tertiary structure than dissociated B-phycoerythrin determined by circular dichroism.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Ficoeritrina/isolamento & purificação , Rodófitas/química , Eletroforese em Gel de Poliacrilamida , Ficoeritrina/química , Espectrofotometria Ultravioleta
20.
Physiol Behav ; 37(3): 519-20, 1986.
Artigo em Inglês | MEDLINE | ID: mdl-3755834

RESUMO

Listings for programs designed to transfer numeric ASCII data files between Apple and IBM personal computers are provided with accompanying descriptions of how the software operates. Details of the hardware used are also given. The programs may be easily adapted for transferring data between other microcomputers.


Assuntos
Computadores , Microcomputadores , Software
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA