Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 114
Filtrar
1.
Nature ; 563(7731): 365-368, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30429552

RESUMO

Barnard's star is a red dwarf, and has the largest proper motion (apparent motion across the sky) of all known stars. At a distance of 1.8 parsecs1, it is the closest single star to the Sun; only the three stars in the α Centauri system are closer. Barnard's star is also among the least magnetically active red dwarfs known2,3 and has an estimated age older than the Solar System. Its properties make it a prime target for planetary searches; various techniques with different sensitivity limits have been used previously, including radial-velocity imaging4-6, astrometry7,8 and direct imaging9, but all ultimately led to negative or null results. Here we combine numerous measurements from high-precision radial-velocity instruments, revealing the presence of a low-amplitude periodic signal with a period of 233 days. Independent photometric and spectroscopic monitoring, as well as an analysis of instrumental systematic effects, suggest that this signal is best explained as arising from a planetary companion. The candidate planet around Barnard's star is a cold super-Earth, with a minimum mass of 3.2 times that of Earth, orbiting near its snow line (the minimum distance from the star at which volatile compounds could condense). The combination of all radial-velocity datasets spanning 20 years of measurements additionally reveals a long-term modulation that could arise from a stellar magnetic-activity cycle or from a more distant planetary object. Because of its proximity to the Sun, the candidate planet has a maximum angular separation of 220 milliarcseconds from Barnard's star, making it an excellent target for direct imaging and astrometric observations in the future.

2.
Exp Astron (Dordr) ; 57(1): 5, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39308933

RESUMO

State-of-the-art 19th century spectroscopy led to the discovery of quantum mechanics, and 20th century spectroscopy led to the confirmation of quantum electrodynamics. State-of-the-art 21st century astrophysical spectrographs, especially ANDES at ESO's ELT, have another opportunity to play a key role in the search for, and characterization of, the new physics which is known to be out there, waiting to be discovered. We rely on detailed simulations and forecast techniques to discuss four important examples of this point: big bang nucleosynthesis, the evolution of the cosmic microwave background temperature, tests of the universality of physical laws, and a real-time model-independent mapping of the expansion history of the universe (also known as the redshift drift). The last two are among the flagship science drivers for the ELT. We also highlight what is required for the ESO community to be able to play a meaningful role in 2030s fundamental cosmology and show that, even if ANDES only provides null results, such 'minimum guaranteed science' will be in the form of constraints on key cosmological paradigms: these are independent from, and can be competitive with, those obtained from traditional cosmological probes.

3.
FEMS Yeast Res ; 21(2)2021 03 18.
Artigo em Inglês | MEDLINE | ID: mdl-33493281

RESUMO

Scheffersomyces stipitis is a Crabtree-negative pentose fermenting yeast, which shows a complex respiratory system involving a cytochrome and an alternative salicylhydroxamic acid (SHAM)-sensitive respiration mechanism that is poorly understood. This work aimed to investigate the role of the antimycin A (AA) sensitive respiration and SHAM-sensitive respiration in the metabolism of xylose and glucose by S. stipitis, upon different agitation conditions. Inhibition of the SHAM-sensitive respiration caused a significant (P < 0.05) decrease in glycolytic flux and oxygen consumption when using glucose and xylose under agitation conditions, but without agitation, only a mild reduction was observed. The combination of SHAM and AA abolished respiration, depleting the glycolytic flux using both carbon sources tested, leading to increased ethanol production of 21.05 g/L at 250 rpm for 0.5 M glucose, and 8.3 g/L ethanol using xylose. In contrast, inhibition of only the AA-sensitive respiration, caused increased ethanol production to 30 g/L using 0.5 M glucose at 250 rpm, and 11.3 g/L from 0.5 M xylose without agitation. Results showed that ethanol production can be induced by respiration inhibition, but the active role of SHAM-sensitive respiration should be considered to investigate better conditions to increase and optimize yields.


Assuntos
Etanol/análise , Fermentação , Glucose/metabolismo , Consumo de Oxigênio , Saccharomycetales/metabolismo , Xilose/metabolismo , Antifúngicos/farmacologia , Antimicina A/farmacologia , Etanol/metabolismo , Saccharomycetales/efeitos dos fármacos
4.
FEMS Yeast Res ; 19(2)2019 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-30500899

RESUMO

Scheffersomyces stipitis shows a high capacity to ferment xylose, with a strong oxygen dependence to allow NAD+ regeneration. However, without oxygen regeneration of NADH occurs by other metabolic pathways like alcoholic fermentation. There are few reports about inhibitors of mitochondrial respiration and their effects on growth and fermentation. This work aimed to explore the effect of cytochrome bc1 complex inhibition by antimycin A (AA), on growth and fermentation of S. stipitis using glucose, xylose and arabinose as carbon sources, at three agitation levels (0, 125 and 250 rpm). It was possible to discriminate between respiratory and fermentative metabolism in these different conditions using xylose or arabinose. Despite the inhibition of mitochondrial respiration, the glycolytic flux was active because S. stipitis metabolized glucose or xylose to produce ATP; on 0.5 M glucose the cells yielded 17-33 g L-1 ethanol. However, more complex results were obtained on xylose, which depended upon agitation conditions where ethanol production without agitation increased up to 11 g L-1. Inhibition of respiratory chain in S. stipitis could therefore be a good strategy to improve ethanol yields.


Assuntos
Arabinose/metabolismo , Carbono/metabolismo , Complexo III da Cadeia de Transporte de Elétrons/antagonistas & inibidores , Glucose/metabolismo , Saccharomycetales/crescimento & desenvolvimento , Saccharomycetales/metabolismo , Xilose/metabolismo , Antimicina A/metabolismo , Inibidores Enzimáticos/metabolismo , Etanol/metabolismo , Fermentação/efeitos dos fármacos , Glicólise , Análise do Fluxo Metabólico , Oxirredução , Saccharomycetales/efeitos dos fármacos
5.
Braz J Biol ; 84: e282664, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39109724

RESUMO

In the last few years, there has been an increasing interest in solutions for sustainable agriculture to reduce negative impacts on the environment resulting from modern agricultural practices. The use of environmentally beneficial bacteria, like Pseudomonas, which can increase plant productivity by reducing growth time, is a promising opportunity for sustainable agriculture. Pseudomonas is a gram-negative bacterium genus, commonly present in soils, plants, and irrigation water. Pseudomonas has a wide range of metabolic routes that could benefit agriculture, such as nutrient uptake, pathogen suppression, heavy metal solubilization, drought tolerance, and high salt concentration tolerance. Pseudomonas may even be proposed as a potential tool for future agriculture on other planets, where the use of microorganisms would be essential for crop development in hostile and inhospitable environments. Hence, the present review discusses the potential use of Pseudomonas in sustainable agriculture on planet Earth and potentially on Mars, highlighting its role in plant growth enhancement and plant protection from pathogenic microorganisms.


Assuntos
Agricultura , Pseudomonas , Pseudomonas/fisiologia , Microbiologia do Solo , Desenvolvimento Vegetal/fisiologia
6.
J Phys Condens Matter ; 35(35)2023 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-37253372

RESUMO

Barium titanate (BaTiO3) single crystal with a tetragonal phase was characterized by nanoindentation. Elastic and elastic-plastic deformation regimes were obtained. The main objective was the evaluation of the anisotropic behavior related to mechanical properties associated with the cross-section of the ferroelectrica- andc-domains (In-plane and out-of-plane) in (001) configuration domains. This behavior was evaluated along a line perpendicular to the between domains, which demonstrated that the mechanical properties of the BaTiO3single crystal depend on the distance from due to the effect of the influence of the neighbor domain. A three-dimensional (3D) finite element (FE) model was developed to simulate mechanical effects revealed by the nanoindentations test. The FE simulation demonstrated that there is no simple isotropic mechanical behavior associated with the domain type. Numerical simulations and experiments performed to study ferroelastic switching domains in BaTiO3crystals revealed the interaction of the 90°-cadomain with the indentation position.

7.
J Mech Behav Biomed Mater ; 117: 104404, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33667799

RESUMO

Guided bone regeneration surgeries are based on grafting a scaffold in the site to be repaired. The main focus of the scaffold is to provide mechanical support to newly formed blood vessels and cells that will colonize the grafted site, achiving bone regenertation. In this regards, the aim of this study was to characterize the anatomy, structular, surface morphologycal, chemical composition, and nanomechanical properties of ostrich and equine trabecular bone. Ostrich and equine specimens were obtained from a local abattoir and bone was obtained by blunt dissection, n = 5. Tissue bone anatomy and trabecular structure were measured using Computerized Axial Tomography (CAT). Atomic Force Microscopy (AFM) and Energy dispersion spectrometry of X-ray (EDS) were used to examine surface morphology and chemical composition of the trabecular ostrich and equine bone. Mechanical behavior was analysted by nanoindentation. Equine specimens were examined as control. CAT results suggest that in terms of anthropometry, ostrich tarsometatarsus bone is more suitable due to its length is 432.56 ± 3.12 mm vs. the highest human bone structures reported, which femur length is 533.66 ± 18.81 mm. Besides, the low radiodensity in the Hounsfield scale exhibits equine trabecular bone more brittle (Av = 1538.4 ± 0.9) than ostrich trabecular bone (Av = 462.1 ± 1.5). EDS showed a slight variation of the element Calcium (Ca2+) ranging from 20% to 25.5% wt in equine bone; the Ca2+ content variation is consistent with the ring-shaped morphology, while in ostrich bone the chemical composition is homogeneous. The elastic modulus, nanohardness (E = 5.3 ± 0.7 GPa, H = 220 ± 10 MPa) and average roughness (Ra = 207 nm) are similar to the human trabecular bone which could reduce the stress shielding, all of these findings suggest that ostrich bone can be promising for native tissue scaffolds for mechanically demanding applications. This research makes innovative contributions to science and provides a framework, which will allow us to address future biomedical tests, and rapidly identify promising organic and sustainable waste for tissue scaffold.


Assuntos
Osso e Ossos , Osso Cortical , Animais , Fenômenos Biomecânicos , Osso e Ossos/diagnóstico por imagem , Módulo de Elasticidade , Elasticidade , Cavalos , Microscopia de Força Atômica , Estresse Mecânico
8.
PLoS One ; 15(8): e0237715, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32822374

RESUMO

Transcriptomic responses of plants to weed presence gives insight on the physiological and molecular mechanisms involved in the stress response. This study evaluated transcriptomic and morphological responses of two teosinte (Zea mays ssp parviglumis) (an ancestor of domesticated maize) lines (Ames 21812 and Ames 21789) to weed presence and absence during two growing seasons. Responses were compared after 6 weeks of growth in Aurora, South Dakota, USA. Plant heights between treatments were similar in Ames 21812, whereas branch number decreased when weeds were present. Ames 21789 was 45% shorter in weedy vs weed-free plots, but branch numbers were similar between treatments. Season-long biomass was reduced in response to weed stress in both lines. Common down-regulated subnetworks in weed-stressed plants were related to light, photosynthesis, and carbon cycles. Several unique response networks (e.g. aging, response to chitin) and gene sets were present in each line. Comparing transcriptomic responses of maize (determined in an adjacent study) and teosinte lines indicated three common gene ontologies up-regulated when weed-stressed: jasmonic acid response/signaling, UDP-glucosyl and glucuronyltransferases, and quercetin glucosyltransferase (3-O and 7-O). Overall, morphologic and transcriptomic differences suggest a greater varietal (rather than a conserved) response to weed stress, and implies multiple responses are possible. These findings offer insights into opportunities to define and manipulate gene expression of several different pathways of modern maize varieties to improve performance under weedy conditions.


Assuntos
Plantas Daninhas , Transcriptoma , Zea mays/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas , Ontologia Genética , Luz , Fotossíntese , Plantas Daninhas/fisiologia , Estresse Fisiológico , Zea mays/genética , Zea mays/fisiologia
9.
Theor Appl Genet ; 118(8): 1617-31, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19322557

RESUMO

Traditional quantitative trait loci (QTL) mapping approaches are typically based on early or advanced generation analysis of bi-parental populations. A limitation associated with this methodology is the fact that mapping populations rarely give rise to new cultivars. Additionally, markers linked to the QTL of interest are often not immediately available for use in breeding and they may not be useful within diverse genetic backgrounds. Use of breeding populations for simultaneous QTL mapping, marker validation, marker assisted selection (MAS), and cultivar release has recently caught the attention of plant breeders to circumvent the weaknesses of conventional QTL mapping. The first objective of this study was to test the feasibility of using family-pedigree based QTL mapping techniques generally used with humans and animals within plant breeding populations (PBPs). The second objective was to evaluate two methods (linkage and association) to detect marker-QTL associations. The techniques described in this study were applied to map the well characterized QTL, Fhb1 for Fusarium head blight resistance in wheat (Triticum aestivum L.). The experimental populations consisted of 82 families and 793 individuals. The QTL was mapped using both linkage (variance component and pedigree-wide regression) and association (using quantitative transmission disequilibrium test, QTDT) approaches developed for extended family-pedigrees. Each approach successfully identified the known QTL location with a high probability value. Markers linked to the QTL explained 40-50% of the phenotypic variation. These results show the usefulness of a human genetics approach to detect QTL in PBPs and subsequent use in MAS.


Assuntos
Mapeamento Cromossômico , Fusarium/genética , Doenças das Plantas/genética , Locos de Características Quantitativas , Triticum/genética , Cromossomos de Plantas , Cruzamentos Genéticos , DNA/genética , DNA/isolamento & purificação , DNA de Plantas , Estudos de Viabilidade , Fusarium/imunologia , Marcadores Genéticos , Genótipo , Imunidade Inata/genética , Linhagem , Doenças das Plantas/imunologia , Reprodutibilidade dos Testes , Triticum/imunologia
10.
Neurosci Lett ; 450(1): 7-11, 2009 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-19026720

RESUMO

In this work, we attempt to extend to the schizophrenia's research the evidence that different frequency bands may emerge from different sources during early-stage visual processing, in a mental state-specific manner, while subjects are passively viewing a visual stimulus. We applied standard pattern reversal stimulation (checker-board), a task with low cognitive demands, coupled to a dense EEG recording system to estimate the neural correlates of the evoked theta, alpha, beta, beta1, and gamma frequency band responses by means of brain electrical tomography (BET). After filtering the evoked activity using different band-passes, a very different picture about the current sources during P100 will emerge. The results showed notable differences between the two groups. In healthy subjects we localized the significances in the anterior cingulate, caudate nucleus, thalamus, precuneous region, and superior parietal that were more active for gamma band. In patients with schizophrenia differences occupy the hippocampus, parahippocampus, thalamus, midbrain, precuneus, and superior parietal regions. Most areas were more active for gamma band except precuneous and superior parietal region more active for theta and alpha frequency band. These sets of regions, in both groups, reflect events that are parallel to and partly independent of the P100 component, while in the schizophrenia, these regions have been previous linked to the major symptoms of the disease. We concluded that this result provides important evidence indicating that the proposed method is able to differentiate electrophysiological patterns in healthy subjects from those in patients with schizophrenia.


Assuntos
Encéfalo/fisiopatologia , Esquizofrenia/fisiopatologia , Percepção Visual , Adulto , Análise de Variância , Mapeamento Encefálico , Eletroencefalografia , Potenciais Evocados , Humanos , Esquizofrenia/diagnóstico , Tomografia , Adulto Jovem
11.
Neurosci Lett ; 442(3): 273-8, 2008 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-18634853

RESUMO

Although diagnostic procedures have been developed for detection of mild cognitive impairment (MCI) and mild Alzheimer dementia (AD), more valid noninvasive tools are needed. In this work, we apply a procedure based on the evidences that different evoked frequency band responses may emerge from different sources during early-stage visual processing in a mental state-specific manner, while subjects were passively viewing a visual stimulus. In this case, spatial differences should arise across mental conditions such as mild Alzheimer dementia, mild cognitive impairment, and normal aging. With the use of EEG source image we found three different neural patterns in aged individuals: (1) left hippocampus and midbrain in mild AD, (2) left lateral orbitofrontal gyrus, left nucleus accumbens, caudate nucleus, thalamus, posterior cinguli, right precuneous, right superior parietal lobe in MCI, and (3) right lateral-medial orbitofrontal gyrus, caudate nucleus, thalamus, right lateral occipitotemporal gyrus in elderly controls. Although preliminary, these results show remarkably robust differences that distinguish between an age-matched control group, a group with MCI, and a group with mild AD. Because the method applied in this work differentiates among clinical entities with varying severity of cognitive decline, it may eventually serve as an electrophysiological marker in the early detection of neurodegeneration.


Assuntos
Envelhecimento/fisiologia , Doença de Alzheimer/fisiopatologia , Transtornos Cognitivos/fisiopatologia , Potenciais Evocados Visuais/fisiologia , Percepção Visual/fisiologia , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/diagnóstico , Mapeamento Encefálico , Transtornos Cognitivos/diagnóstico , Eletroencefalografia , Feminino , Humanos , Masculino
12.
Rev Esp Enferm Dig ; 100(1): 24-8, 2008 Jan.
Artigo em Espanhol | MEDLINE | ID: mdl-18358057

RESUMO

INTRODUCTION: Celiac disease (CD) is a chronic immune-mediated enteropathy, resulting from a gluten intolerance in genetically predisposed individuals. OBJECTIVE: a) to describe clinical features, associated disorders and serology of CD in adults; and b) to study the main that serology displays in diagnosis, clinical and histological expression. PATIENTS AND METHODS: 31 patients diagnosed of CD in adulthood have been reviewed retrospectively, including clinical presentation, associated disorders, biochemical results, serological tests (anti-gliadin and anti-endomysial antibodies) and genetical features (HLA-DQ2). It has been studied the relation between typical presentations and AEm with clinical, serological or histological findings. RESULTS: Almost 50% of patients had atypical clinical manifestations and gastrointestinal symptoms were absent in 33%. Typical manifestations are associated with villous atrophy stage III b-c of Marsh's classification (87 vs. 53%, p = 0,03). 70% of patients shows AEm mostly in women (78 vs. 37%, p = 0.03) and stage III b-c of Marsh (84 vs. 50%, p = 0.05). 68,4% were DQ2 positive. CONCLUSIONS: Clinical features of CD varies greatly. AEm and DQ2 are less common than others studies. There may be an association with clinical and serological findings and villous atrophy stage. Genetical features could help AEm in diagnosis.


Assuntos
Doença Celíaca/diagnóstico , Adulto , Doença Celíaca/sangue , Doença Celíaca/complicações , Doença Celíaca/imunologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
13.
Eur Rev Med Pharmacol Sci ; 11(1): 21-5, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17405346

RESUMO

BACKGROUND AND OBJECTIVE: Insulin resistance has been associated with fat liver and non-alcoholic fatty liver disease. The aim of our study was to study the influence of insulin resistance in obese patients on elevated serum alanine aminotransferase. RESEARCH METHODS: A population of 91 obesity non diabetic outpatients was analyzed in a cross sectional study. HOMA-IR was calculated as indicator of insulin resistance. RESULTS: The mean age was 39.2 +/- 16.7 years and the mean BMI 34.4 +/- 5.2. Patients were classified as group I (control, n=74) when serum (Alanine Aminotransferase) ALT activity was normal or group II (NAFLD, n=17) when serum ALT activity was greater than the upper limit of normal reference laboratory (> or =43 UI/L). Waist circumference, fat mass and hip to waist ratio were higher in group II. Insulin (13.5 +/- 7.8 mUI/L vs 24.9 +/- 16.7 mUI/L; p < 0.05), HOMA-IR (1.9 +/- 1.1 vs 3.9 +/- 2.8), and triglycerides levels (115.1 +/- 66.8 mg/dl vs. 153.2 +/- 71.2 mg/dl; p < 0.05) were higher in group II than group I. In the logistic regression analysis with a dependent dicotomic variable (ALT; group I and group II), the HOMA-IR remained in the model, with an Odd's Ratio to develop ALT >43 U/L of 2.18 (CI:95%: 1.12-4.2) with each 1 unit of HOMA-IR adjusted by age, sex, weight, and dietary intake. CONCLUSION: Insulin resistance in obese patients is associated with ALT activity. Further study is needed to evaluate histological changes and new treatments in these patients.


Assuntos
Alanina Transaminase/sangue , Resistência à Insulina , Obesidade/sangue , Adulto , Índice de Massa Corporal , Doenças Cardiovasculares/sangue , HDL-Colesterol/sangue , Estudos Transversais , Feminino , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Obesidade/fisiopatologia , Fatores de Risco , Triglicerídeos/sangue , Relação Cintura-Quadril
14.
Rev Esp Enferm Dig ; 99(1): 19-24, 2007 Jan.
Artigo em Espanhol | MEDLINE | ID: mdl-17295594

RESUMO

INTRODUCTION: Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors in the gastrointestinal tract. One of their features is the expression of the c-KIT/CD117 receptor. AIMS AND METHODS: We will focus on describing the symptoms, clinical studies prior to diagnosis, histologic and immunohistochemical characteristics, as well as the progression of disease in a group of patients. RESULTS: Seventeen cases were diagnosed between December 1999 and April 2005. Mean age of patients was 64.5 (+/-11.9); 47% were women. Tumor location was as follows: 52.9% in the jejunum or ileum, 29.4% were gastric, 11.7% were in the duodenum, and 5.8% were located in the mesentery. Tumor size was 6.0 cm on average (+/-5.0); 47% were asymptomatic, and to a lesser degree caused abdominal pain or digestive bleeding; 94.1% of tumors expressed CD117. Most of them were discovered while performing a laparotomy or ultrasound scan; 94.1% of tumors were removed; 35.2% (6 out of 17) of patients suffering from GIST met consensus criteria for aggressive behavior. Over 25.6 months (+/-22.5) metastasis or tumor relapse occurred in 23.5% (4 out of 17) of patients--those with more frequent high-risk criteria, symptomatic and bigger tumors, and tumors not expressing CD117. The three patients with tumor relapse were prescribed imatinib mesylate. Three patients died because of the tumor, and four from other causes unrelated to GIST. CONCLUSIONS: GIST was diagnosed in around 12 cases per million a year. Its diagnosis was usually an incidental finding during a medical evaluation, and tumors were malignant in nearly one fourth of cases. We can predict its outcome depending on different aspects.


Assuntos
Tumores do Estroma Gastrointestinal/diagnóstico , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
15.
Rev Neurol ; 44(9): 519-23, 2007.
Artigo em Espanhol | MEDLINE | ID: mdl-17492608

RESUMO

INTRODUCTION: Attention-deficit/hyperactivity disorder (ADHD) is the main neurological diagnosis in Chilean children. Its profile and evolution in adults has not been appropriately studied, despise its personal and social impact. AIM: To describe the characteristics of adults with ADHD evaluated in a memory unit, verifying the existence of differences depending on gender. PATIENTS AND METHODS: A demographic and symptomatic evaluation protocol was applied to all patients diagnosed with ADHD who consulted at the Memory Unit of the Pontificia Universidad Católica de Chile, during the year 2004. RESULTS: Eighty six patients were included. Average age was 37, being 53% male. Most patients were diagnosed for the first time in adulthood, corresponding to an ADHD of combined type. The main patients' complaints were forgetfulness and distraction. A stressing factor capable of worsening the symptoms was identified in 59% of patients. Depression was the principal comorbidity, with a significantly higher incidence in women. CONCLUSIONS: The limitations of ADHD diagnostic criteria available for adult patients are discussed. Differences depending on gender were analyzed, describing a predominantly disruptive profile in men and depressive profile in women. There is a clear under-diagnosis of female children with ADHD, with a potential negative impact on their neuropsychological development. The differential diagnosis with mild cognitive impairment, in patients complaining of recent memory decline is discussed.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/diagnóstico , Memória/fisiologia , Adulto , Transtorno do Deficit de Atenção com Hiperatividade/fisiopatologia , Criança , Chile , Comorbidade , Depressão/fisiopatologia , Feminino , Humanos , Masculino , Transtornos da Memória/diagnóstico , Transtornos da Memória/etiologia , Pessoa de Meia-Idade , Testes Neuropsicológicos , Fatores Sexuais
16.
Cuad. psicol. deporte ; 22(1): 124-137, ene. - abr. 2022. ilus, tab
Artigo em Espanhol | IBECS (Espanha) | ID: ibc-208963

RESUMO

El uso excesivo de los videojuegos y la adicción a los mismos entre los deportistas es una preocupación reciente que va en aumento. La sensibilidad a la ansiedad es un factor de riesgo para las conductas adictivas, del mismo modo que la dureza mental, ampliamente asociada a los deportistas, es un elemento protector. El presente trabajo examina las relaciones entre la sensibilidad a la ansiedad, la dureza mental y la adicción a videojuegos en este contexto. La muestra estuvo compuesta por deportistas (n = 98) de entre 19 -51 años (M edad = 23.94; DT = 7.72) de los cuales 64 fueron hombres y 34 mujeres. Aplicando instrumentos descriptivos sobre sensibilidad a la ansiedad, dureza mental y adicción y dependencia a los videojuegos los resultados indicaron que un aumento de la sensibilidad a la ansiedad física o social correlacionó con una disminución de la dureza mental y la reducción de ésta se asoció con un aumento de la tolerancia a los video juegos. La sensibilidad a la ansiedad social y física tuvo efectos indirectos en el abuso y tolerancia a los videojuegos mediante la dureza mental de los deportistas. Los resultados se discuten entorno al papel de la dureza mental en la comprensión de los problemas de adicción a los videojuegos en deportistas. (AU)


Video game overuse and addiction among athletes is a recent and growing concern. Anxiety sensitivity is a risk factor for addictive behaviors, just as mental toughness, widely associated with athletes, is a protective element. The present study examines the relationships between anxiety sensitivity, mental toughness and video game addiction in this context. The sample was composed of athletes (n = 98) aged 19-51 years (M age = 23.94; SD = 7.72) of whom 64 were male and 34 females. Applying descriptive instruments on anxiety sensitivity, mental toughness and video game addiction and dependence, the results indicated that an increase in physical or social anxiety sensitivity correlated with a decrease in mental toughness that in turn was associated with an increase in video game tolerance. Sensitivity to social and physical anxiety had indirect effects on video game abuse and tolerance through mental toughness in athletes. The results are discussed around the role of mental toughness in understanding video game addiction problems in athletes. (AU)


O uso excessivo e a dependência dos jogos de vídeo entre os atletas é uma preocupação recente e crescente. A sensibilidade à ansiedade é um facto de risco para comportamentos viciantes, tal como a resistência mental, amplamente associada aos atletas, é um elemento protetor. O presente estudo examina as relações entre a sensibilidade à ansiedade, resistência mental e dependência de jogos de vídeo neste contexto. A amostra foi composta por atletas (n = 98) com idades entre 19-51 anos (M idade = 23,94; T.D. = 7,72) dos quais 64 eram do sexo masculino, 34 do sexo feminino. Aplicando instrumentos descritivos sobre a sensibilidade à ansiedade, resistência mental, dependência e dependência de jogos de vídeo, os resultados indicaram que um aumento da sensibilidade à ansiedade física ou social correlacionada com uma diminuição da resistência mental, e esta diminuição foi associada a um aumento da tolerância aos jogos de vídeo. A sensibilidade à ansiedade social e física teve efeitos indiretos no abuso e tolerância dos jogos de vídeo através da resistência mental dos atletas. Os resultados são discutidos em torno do papel da resistência mental na compreensão dos problemas de vício dos jogos de vídeo nos atletas. (AU)


Assuntos
Humanos , Masculino , Feminino , Adulto Jovem , Adulto , Pessoa de Meia-Idade , Atletas , Ansiedade , Jogos de Vídeo/efeitos adversos , Jogos de Vídeo/psicologia , Psicologia do Esporte , Esportes , Inquéritos e Questionários
17.
Rev. int. med. cienc. act. fis. deporte ; 22(85): 107-127, mar.-mayo 2022.
Artigo em Inglês, Espanhol | IBECS (Espanha) | ID: ibc-205431

RESUMO

La Ansiedad-Rasgo es una medida disposicional y estable, siendo en el contexto deportivo relevante su evaluación, por la interpretación que realiza el deportista de sus sensaciones ansiosas para el rendimiento competitivo. El propósito ha sido la adaptación al español del Competitive Trait Anxiety Inventory (CTAI-2D), en 421 deportistas (66.3% hombres y 33.7% mujeres) con edades entre los 18 y 46 años (Medad = 21.16). En primer lugar, se efectuó la traducción del CTAI-2D, junto con el análisis factorial exploratorio (AFE) y validez convergente; y, en segundo lugar, se realizó el análisis factorial confirmatorio (AFC). El AFE ha mostrado una varianza explicada del 52.95% para la dimensión intensidad y 55.55% para valencia/dirección; mientras el AFC muestra índices de ajuste satisfactorios. El CTAI-2D es un instrumento para evaluar el rasgo, válido y fiable, aportando la percepción del deportista acerca de la intensidad de la ansiedad y la interpretación como obstaculizadora o facilitadora. (AU)


Trait-Anxiety is a dispositional and stable measure, its evaluation being relevant in the sporting context, due to the athlete's interpretation of their anxious feelings for competitive performance. The purpose has been to adapt Competitive Trait Anxiety Inventory (CTAI-2D) into Spanish in 421 athletes (66.3% men and 33.7% women) aged between 18 and 46 years (Average = 21.16). In the first place, the translation of the CTAI-2D was performed, together with exploratory factor analysis (EFA) and convergent validity; and, secondly, confirmatory factor analysis (CFA) was performed. The EFA has shown an explained variance of 52.95% for the intensity dimension and 55.55% for valence / direction; while the AFC shows satisfactory adjustment indices. The CTAI-2D is an instrument to evaluate the trait, valid and reliable, providing the athlete's perception of the intensity of anxiety and the interpretation as an obstacle or facilitator. (AU)


Assuntos
Humanos , Adulto Jovem , Adulto , Ansiedade , Atletas , Exercício Físico , Desempenho Atlético , Espanha , Análise Fatorial , Traduções
18.
Phytopathology ; 96(8): 885-9, 2006 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-18943754

RESUMO

ABSTRACT Race 3 of the fungus Pyrenophora tritici-repentis, causal agent of tan spot, induces differential symptoms in tetraploid and hexaploid wheat, causing necrosis and chlorosis, respectively. This study was conducted to examine the genetic control of resistance to necrosis induced by P. tritici-repentis race 3 and to map resistance genes identified in tetraploid wheat (Triticum turgidum). A mapping population of recombinant inbred lines (RILs) was developed from a cross between the resistant genotype T. tur-gidum no. 283 (PI 352519) and the susceptible durum cv. Coulter. Based on the reactions of the Langdon-T. dicoccoides (LDN[DIC]) disomic substitution lines, chromosomal location of the resistance genes was determined and further molecular mapping of the resistance genes for race 3 was conducted in 80 RILs of the cross T. turgidum no. 283/Coulter. Plants were inoculated at the two-leaf stage and disease reaction was assessed 8 days after inoculation based on lesion type. Disease reaction of the LDN(DIC) lines and molecular mapping on the T. turgidum no. 283/Coulter population indicated that the gene, designated tsn2, conditioning resistance to race 3 is located on the long arm of chromosome 3B. Genetic analysis of the F(2) generation and of the F(4:5) and F(6:7) families indicated that a single recessive gene controlled resistance to necrosis induced by race 3 in the cross studied.

19.
Med Hypotheses ; 66(2): 300-8, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16199129

RESUMO

Molecular data and gene expression data and recently mitochondrial genes and possible epigenetic regulation by non-coding genes is revolutionizing our views on schizophrenia. Genes and epigenetic mechanisms are triggered by cell-cell interaction and by external stimuli. A number of recent clinical and molecular observations indicate that epigenetic factors may be operational in the origin of the illness. Based on the molecular insights, gene expression profiles and epigenetic regulation of gene, we went back to the neurophysiology (brain oscillations) and found a putative role of the visual experiences (i.e. visual stimuli) as epigenetic factor. The functional evidences provided here, establish a direct link between the striate and extrastriate unimodal visual cortex and the neurobiology of the schizophrenia. This result support the hypothesis that 'visual experience' has a potential role as epigenetic factor and contribute to trigger and/or to maintain the progression of the schizophrenia. In this case, candidate genes sensible for the visual 'insult' may be located within the visual cortex including associative areas, while the integrity of the visual pathway before reaching the primary visual cortex is preserved. The same effect can be perceived if target genes are localised within the visual pathway, which actually, is more sensitive for 'insult' during the early life than the cortex per se. If this process affects gene expression at these sites a stably sensory specific 'insult', i.e. distorted visual information, is entering the visual system and expanded to fronto-temporo-parietal multimodal areas even from early maturation periods. The difference in the timing of postnatal neuroanatomical events between such areas and the primary visual cortex in humans (with the formers reaching the same development landmarks later in life than the latter) is 'optimal' to establish an abnormal 'cell- communication' mediated by the visual system that may further interfere with the local physiology. In this context the strategy to search target genes need to be rearrangement and redirected to visual-related genes. Otherwise, psychophysics studies combining functional neuroimage, and electrophysiology are strongly recommended, for the search of epigenetic clues that will allow to carrier gene association studies in schizophrenia.


Assuntos
Epigênese Genética , Esquizofrenia/genética , Vias Visuais , Humanos , Vias Visuais/anatomia & histologia
20.
Complement Ther Med ; 14(1): 31-8, 2006 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-16473751

RESUMO

OBJECTIVES: The aim of this work was to compare in vivo measurements of direct current (dc) and alternating current (ac) obtained from acupuncture points in Ukrainian and Mexican residents. METHODS: Measurements were made using the method of Voll. The participants were 43 healthy Ukrainian and 71 healthy Mexican residents aged between 20 and 30 years, as well as 24 Mexican patients with a clinical diagnosis of rheumatoid arthritis and 14 patients with a clinical diagnosis of allergy. RESULTS: The results showed that dc measurements are not directly applicable to different populations. Thus, the dc resistance of the acupuncture points in the Mexican participants was 4-5 times larger than in the Ukrainians. In contrast, the capacitance of the two groups did not differ by more than 25%. CONCLUSIONS: Impedance measurements from acupuncture points can be used as an efficient and prompt non-invasive method for diagnostic purposes.


Assuntos
Pontos de Acupuntura , Adulto , Artrite Reumatoide/fisiopatologia , Impedância Elétrica , Humanos , Hipersensibilidade/fisiopatologia , México , Ucrânia
SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa