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1.
Front Public Health ; 8: 526468, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33072692

RESUMEN

Human movement affects malaria epidemiology at multiple geographical levels; however, few studies measure the role of human movement in the Amazon Region due to the challenging conditions and cost of movement tracking technologies. We developed an open-source low-cost 3D printable GPS-tracker and used this technology in a cohort study to characterize the role of human population movement in malaria epidemiology in a rural riverine village in the Peruvian Amazon. In this pilot study of 20 participants (mean age = 40 years old), 45,980 GPS coordinates were recorded over 1 month. Characteristic movement patterns were observed relative to the infection status and occupation of the participants. Applying two analytical animal movement ecology methods, utilization distributions (UDs) and integrated step selection functions (iSSF), we showed contrasting environmental selection and space use patterns according to infection status. These data suggested an important role of human movement in the epidemiology of malaria in the Peruvian Amazon due to high connectivity between villages of the same riverine network, suggesting limitations of current community-based control strategies. We additionally demonstrate the utility of this low-cost technology with movement ecology analysis to characterize human movement in resource-poor environments.


Asunto(s)
Malaria , Ríos , Adulto , Animales , Estudios de Cohortes , Humanos , Malaria/epidemiología , Perú/epidemiología , Proyectos Piloto
2.
Plant Soil ; 452(1): 587-600, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32713967

RESUMEN

AIMS: Selection for optimal root system architecture (RSA) is important to ensure genetic gains in the sustainable production of wheat (Triticum aestivum L.). Here we examine the hypothesis that past wheat breeding has led to changes in RSA and that future breeding efforts can focus directly on RSA to improve adaptation to target environments. METHODS: We conducted field trials using diverse wheat varieties, including modern and historic UK varieties and non-UK landraces, tested under contrasting tillage regimes (non-inversion tillage versus conventional ploughing) for two trial years or different seeding rates (standard versus high rate) for one trial year. We used field excavation, washing and measurement of root crowns ('shovelomics') to characterise RSA traits, including: numbers of seminal, crown and nodal roots per plant, and crown root growth angle. RESULTS: We found differences among genotypes for all root traits. Modern varieties generally had fewer roots per plant than historic varieties. On average, there were fewer crown roots and root angles were wider under shallow non-inversion tillage compared with conventional ploughing. Crown root numbers per plant also tended to be smaller at a high seeding rate compared with the standard. There were significant genotype-by-year, genotype-by-tillage and genotype-by-seeding-rate interactions for many root traits. CONCLUSIONS: Smaller root systems are likely to be a result of past selection that facilitated historical yield increases by reducing below-ground competition within the crop. The effects of crop management practices on RSA depend on genotype, suggesting that future breeding could select for improved RSA traits in resource-efficient farming systems.

3.
Plant Soil ; 415(1): 407-422, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-32025056

RESUMEN

BACKGROUND AND AIMS: There is an urgent need to develop new high throughput approaches to phenotype roots in the field. Excavating roots to make direct measurements is labour intensive. An alternative to excavation is to measure soil drying profiles and to infer root activity. METHODS: We grew 23 lines of wheat in 2013, 2014 and 2015. In each year we estimated soil water profiles with electrical resistance tomography (ERT), electromagnetic inductance (EMI), penetrometer measurements and measurements of soil water content. We determined the relationships between the measured variable and soil water content and matric potential. RESULTS: We found that ERT and penetrometer measurements were closely related to soil matric potential and produced the best discrimination between wheat lines. We found genotypic differences in depth of water uptake in soil water profiles and in the extent of surface drying. CONCLUSIONS: Penetrometer measurements can provide a reliable approach to comparing soil drying profiles by different wheat lines, and genotypic rankings are repeatable across years. EMI, which is more sensitive to soil water content than matric potential, and is less effective in drier soils than the penetrometer or ERT, nevertheless can be used to rapidly screen large populations for differences in root activity.

4.
J Exp Bot ; 64(13): 3951-63, 2013 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-23526772

RESUMEN

The availability of soil water, and the ability of plants to extract it, are important variables in plant research. The matric potential has been a useful way to describe water status in a soil-plant system. In soil it is the potential that is derived from the surface tension of water menisci between soil particles. The magnitude of matric potential depends on the soil water content, the size of the soil pores, the surface properties of the soil particles, and the surface tension of the soil water. Of all the measures of soil water, matric potential is perhaps the most useful for plant scientists. In this review, the relationship between matric potential and soil water content is explored. It is shown that for any given soil type, this relationship is not unique and therefore both soil water content and matric potential need to be measured for the soil water status to be fully described. However, in comparison with water content, approaches for measuring matric potential have received less attention until recently. In this review, a critique of current methods to measure matric potential is presented, together with their limitations as well as underexploited opportunities. The relative merits of both direct and indirect methods to measure matric potential are discussed. The different approaches needed in wet and dry soil are outlined. In the final part of the paper, the emerging technologies are discussed in so far as our current imagination allows. The review draws upon current developments in the field of civil engineering where the measurement of matric potential is also important. The approaches made by civil engineers have been more imaginative than those of plant and soil scientists.


Asunto(s)
Técnicas Biosensibles/métodos , Suelo/química , Agua/análisis , Raíces de Plantas/metabolismo , Rizosfera , Transductores de Presión
5.
Hernia ; 15(1): 53-8, 2011 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-20953888

RESUMEN

BACKGROUND: The histological study of the herniated inguinal area is rare in the literature. This report is focused on the detection of structural changes of the nerves within tissues bordering the inguinal hernia of cadavers. Their physiopathological consequences are hypothesized. MATERIALS AND METHODS: Primary inguinal hernia was diagnosed in 30 fresh cadavers. Tissue specimens from the inguinal region close to and around the hernia opening were excised for histological examination. A control of the data was achieved through tissue samples excised from equivalent sites of the inguinal region in 15 cadavers without hernia. RESULTS: The detected nerves in the inguinal area demonstrated pathological changes such as fibrotic degeneration, atrophy, and fatty dystrophy of the axons. The thickening of the perineural sheath was constantly seen. These findings were consistently present, independent of the hernia type. CONCLUSIONS: The detected nerve alterations lead us to imagine a worsening, or even the cessation, of the nervous impulse to the muscles, leading to atrophy and weakening of the abdominal wall. This could represent one of the multifactorial causes of hernia genesis.


Asunto(s)
Ingle/patología , Hernia Inguinal/patología , Músculo Esquelético/patología , Degeneración Nerviosa/patología , Nervios Periféricos/patología , Pared Abdominal/inervación , Anciano , Cadáver , Fibrosis , Hernia Inguinal/etiología , Humanos , Conducto Inguinal/inervación , Masculino , Persona de Mediana Edad , Degeneración Nerviosa/complicaciones
6.
J Exp Bot ; 60(7): 1919-25, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-19349420

RESUMEN

Sugar beet is spring-sown for sugar production in most sugar beet-growing countries. It is grown as a vegetative crop and it accumulates yield (sugar) from very early in its growth cycle. As long as the sugar beet plants do not flower, the sugar accumulation period is indefinite and yield continues to increase. This paper reviews the success of the sugar beet crop in capturing and using solar radiation, water and mineral nitrogen resources. The prospects for improved resource capture and therefore increased sugar yield are also considered, particularly the potential to increase solar radiation interception in the future by sowing the crop in the autumn.


Asunto(s)
Beta vulgaris/metabolismo , Beta vulgaris/efectos de la radiación , Carbohidratos/biosíntesis , Nitrógeno/metabolismo , Energía Solar , Agua/metabolismo , Beta vulgaris/crecimiento & desarrollo
7.
Ann Bot ; 89 Spec No: 917-24, 2002 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-12102517

RESUMEN

Insufficient soil moisture during summer months is now the major cause of sugar beet yield losses in the UK. However, selection for increased drought tolerance has not been a breeding priority until recently. Genetic variation for drought tolerance is an essential prerequisite for the development of more stress-tolerant varieties, but commercial sugar beet varieties seem to have similar yield responses to drought. The objective of this study was to assess the degree of genotypic variation for drought tolerance within a wide range of sugar beet germplasm and genebank accessions within Beta. Thirty sugar beet genotypes were screened under field drought conditions, and putative drought tolerant and sensitive lines (in terms of yield reduction in polythene-covered vs. irrigated plots) were identified. Significant genotype x water treatment interactions were found for dry matter yield and relative leaf expansion rate. Genotypic differences for drought susceptibility index were also significant. Differential sensitivity of seedling shoot growth to water deficit was examined by comparing 350 genebank accessions in a simple growth chamber screen. Methods of data management were devised to highlight lines for entry into subsequent field tests. The results of the field and seedling screens indicate that there is variation for tolerance to water deficits within sugar beet and related types, and that there are lines that show greater drought tolerance than selected commercial varieties. Divergent lines showing contrasting behaviour should aid in the identification of key morpho-physiological traits that confer drought tolerance.


Asunto(s)
Aclimatación/genética , Beta vulgaris/genética , Agua/fisiología , Aclimatación/fisiología , Beta vulgaris/efectos de los fármacos , Beta vulgaris/crecimiento & desarrollo , Productos Agrícolas/efectos de los fármacos , Productos Agrícolas/genética , Productos Agrícolas/crecimiento & desarrollo , Desastres , Pruebas Genéticas , Variación Genética , Genotipo , Hojas de la Planta/genética , Hojas de la Planta/crecimiento & desarrollo , Agua/farmacología
8.
Dev Biol ; 215(2): 167-81, 1999 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-10545228

RESUMEN

We have analyzed the role of the zebrafish yolk cell in the processes of mesoderm induction and establishment of the organizer. By recombining blastomere-free yolk cells and animal cap tissue we have shown that the yolk cell itself can induce mesoderm in neighboring blastomeres. We further demonstrate the competence of all blastomeres to form mesoderm, suggesting the endogenous mesoderm inducing signal to be locally restricted. Ablation of the vegetal third of the yolk cell during the first 20 min of development does not interfere with mesoderm formation in general, but results in completely ventralized embryos. These embryos lack the notochord, neuroectoderm, and the anterior-most 14-15 somites, demonstrating that the ablation affects the formation of the trunk-, but not the tail region of the embryo. This suggests the presence of a trunk organizer in fish. The dorsalized mutant swirl (zbmp-2b) shows expanded dorsal structures and missing ventral structures. In contrast to the phenotypes obtained upon the ablation treatment in wild-type embryos, removal of the vegetal-most yolk in swirl mutants results in embryos which do form neuroectoderm and anterior trunk somites. However, both wild-type and swirl mutants lack a notochord upon vegetal yolk removal. These ablation experiments in wild-type and swirl mutant embryos demonstrate that in zebrafish dorsal determining factors originate from the vegetal part of the yolk cell. These factors set up two independent activities: one induces the notochord and the other is involved in the formation of the neuroectoderm and the trunk region by counteracting the function of swirl. In addition, these experiments show that the establishment of the anteroposterior axis is independent of the dorsoventral axis.


Asunto(s)
Ectodermo/fisiología , Mesodermo/fisiología , Notocorda/fisiología , Pez Cebra/embriología , Animales , Femenino , Mutación
9.
Mech Dev ; 88(2): 233-6, 1999 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-10534622

RESUMEN

Here we report the cloning of zebrafish erm and pea3 cDNAs, which are members of the PEA3 subgroup of Ets transcription factors. The expression patterns of these two genes were examined during zebrafish embryogenesis. Maternal mRNAs of both genes are detectable and transcripts are found ubiquitously until the late blastula, in the marginal zone of gastrula stages and in the presumptive fore- and hindbrain and in the trunk region of early somite stages. Later, erm expression is observed in distinct regions of the forebrain, the mid-/hindbrain boundary, the differentiating rhombomeres, branchial arches, otic vesicles, the pectoral fins, the somites and the tailbud in a dynamic fashion. In contrast, pea3 is not expressed in the rhombomeres but in the Rohon-Beard neurons, the sensory lateral line placodes and the heart.


Asunto(s)
Encéfalo/embriología , Proteínas de Unión al ADN/genética , Regulación del Desarrollo de la Expresión Génica , Factores de Transcripción/genética , Pez Cebra/embriología , Animales , Encéfalo/metabolismo , Proteínas de Unión al ADN/metabolismo , Embrión no Mamífero , Ojo/embriología , Ojo/metabolismo , Femenino , Corazón/embriología , Datos de Secuencia Molecular , Neuronas/metabolismo , Prosencéfalo/embriología , Prosencéfalo/metabolismo , Rombencéfalo/embriología , Rombencéfalo/metabolismo , Factores de Transcripción/metabolismo , Pez Cebra/genética , Proteínas de Pez Cebra
10.
Chir Narzadow Ruchu Ortop Pol ; 62(1): 67-71, 1997.
Artículo en Polaco | MEDLINE | ID: mdl-9198550

RESUMEN

The new electromyographic test is based on fast Fourier transformation application for analysis of global electromyograms. Specifically designed Dynalog apparatus is described. Dynalog records EMG signal and transfers it to IBM-PC. One hundred thirty-eight global electromyograms were taken from 4 muscle groups (m.rectus femoris, m.deltoideus, mm. flexores antebrachii, mm. extensores antebrachii) in healthy individuals. Standard graphs of power distribution were obtained. Physiologically, at maximum voluntary contraction, power distribution spectrum of 4 muscles display characteristic, repeatable features. The frequency distribution range is 0-250 Hz. The records obtained show an ascending part (10-50 Hz), plateau (50-100 Hz) and mildly descending one at 150 Hz, subsequently to 250 Hz.


Asunto(s)
Electromiografía/métodos , Contracción Muscular/fisiología , Músculo Esquelético/fisiología , Procesamiento de Señales Asistido por Computador , Electromiografía/instrumentación , Diseño de Equipo , Análisis de Fourier , Humanos , Técnicas In Vitro , Valores de Referencia
11.
Chir Narzadow Ruchu Ortop Pol ; 62(2): 145-8, 1997.
Artículo en Polaco | MEDLINE | ID: mdl-9273253

RESUMEN

This study deals with mathematical assessment of physiologic and pathologic EMG frequency distribution by means of ranging. Material consisted of 161 pathologic EMG (63 myogenic cases, 98 neurogenic cases). In physiologic EMG power density distribution shows the highest values between 50 and 100 Hz, the lowest between 200 and 250 Hz. From 0 to 50 Hz power density increases, from 100 to 250 Hz-decreases. In patients with muscular diseases of different etiology the EMG power density spectrum is markedly different. The highest values appear more frequently between 0 and 50 Hz, sometimes also between 100 and 150 Hz. The frequency distribution allows mainly for assessing intensity of EMG pathology; is less useful for determination of its type.


Asunto(s)
Electromiografía , Enfermedades Musculares/diagnóstico , Ortopedia/métodos , Dermatomiositis/diagnóstico , Diagnóstico Diferencial , Humanos , Modelos Biológicos , Paresia/diagnóstico , Poliomielitis/diagnóstico , Polimiositis/diagnóstico , Polineuropatías/diagnóstico , Procesamiento de Señales Asistido por Computador
12.
Plant Physiol ; 105(3): 981-987, 1994 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-12232259

RESUMEN

Previous work showed that the concentration of proline (Pro) increases greatly in the primary root tip of maize (Zea mays L.) at low water potentials ([psi]w). It was also shown that the maintenance of root elongation at low [psi]w depends on increased levels of abscisic acid (ABA). In this study we have assessed whether ABA is required for the increase in Pro concentration. Seedlings were grown in vermiculite of various [psi]w, and endogenous ABA levels were decreased using either fluridone (FLU) or the vp5 mutant to inhibit carotenoid (and ABA) synthesis. In both treatments, Pro concentrations at low [psi]w were substantially decreased throughout the apical centimeter, which encompassed the elongation zone. Pro concentrations in FLU-treated roots were restored by addition of 7 [mu]M ABA to the vermiculite, which raised the internal ABA content to the level in untreated roots at the same [psi]w. Pro and water content profiles were combined with published growth-velocity distributions to calculate the distribution of net Pro and water deposition rates using the continuity equation. At a [psi]w of -1.6 MPa, the rate of Pro deposition in the root tip was decreased by 75% in FLU-treated compared to untreated roots. FLU treatment increased root diameter and, therefore, water content per unit length, but water deposition rates decreased due to the dominant influence of reduced longitudinal expansion. Thus, the decrease in Pro concentration was attributable entirely to the decrease in Pro deposition. The results demonstrate that increased ABA is required for high rates of Pro deposition and, thereby, high Pro concentrations in the growing region of maize primary roots at low [psi]w.

13.
Plant Physiol ; 98(1): 353-6, 1992 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-16668636

RESUMEN

To determine whether abscisic acid (ABA) accumulation in endosperms of water-limited maize (Zea mays L.) plants is from synthesis in maternal plant organs or from intraendosperm synthesis, plants heterozygous for viviparous (vp) genes were self-pollinated to create endosperm genotypes capable (+/-/-; +/+/-; +/+/+) or incapable (-/-/-) of carotenoid and ABA synthesis. The mutants vp2, vp5, and vp7, each in W22 inbred background, were utilized. Both in wild-type endosperms capable of ABA synthesis and in mutants incapable of ABA synthesis, ABA concentrations at 15 days after pollination were substantially increased in response to plant water deficit. We conclude that ABA synthesis in maternal organs was the source of ABA that accumulated in endosperms in response to plant water deficit.

14.
Plant Physiol ; 97(1): 154-64, 1991 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-16668363

RESUMEN

In maize (Zea mays L.), drought during the post-pollination stage decreases kernel growth and often leads to grain yield losses. Kernels in the apical region of the ear are more severely affected than basally positioned kernels. We hypothesized that water deficit during early endosperm development might inhibit kernel growth by decreasing endosperm cell division, and that this response might be mediated by changes in endosperm abscisic acid (ABA) levels. Greenhouse-grown maize, cultivar Pioneer 3925, was subjected to water limitation from 1 to 15 days after pollination (DAP), spanning the period of endosperm cell division and induction of storage product accumulation. Water deficit decreased the number of endosperm nuclei during the treatment period; the most substantial effect was in the apical region of ears. Correspondingly, endosperm fresh weight, starch accumulation and dry mass at maturity were decreased by water limitation. Abscisic acid concentrations in endosperm were quantified by enzyme-linked immunosorbent assay. Water deficit increased ABA concentration in apical-region endosperm by four-fold compared to controls. ABA concentrations were also increased in middle and basal regions of the ear, but to a lesser extent. Two key enzymes in the starch synthesis pathway, sucrose synthase and granule-bound ADP-glucose starch synthase, and zein, the major storage protein in maize endosperm, were studied as markers of storage product synthesis. Water deficit did not affect sucrose synthase enzyme activity or RNA transcript abundance relative to total RNA. However, ADP-glucose starch synthase activity and RNA transcript abundance decreased slightly in apical-region endosperm of water-limited plants by 15 DAP, compared with well-watered controls. In contrast to starch, there was no treatment effect on the accumulation of zein, evaluated at either the polypeptide or RNA level. We conclude that under the conditions tested, the establishment of starch and zein synthetic potential in endosperm was only slightly affected by plant water deficit during the early phase of kernel growth, and that capacity for growth and starch accumulation was affected by the extent to which cell division was inhibited. Based on correlative changes in ABA concentration and cell division we suggest that ABA may play a role in inhibiting endosperm cell division during water limitation.

15.
Anat Anz ; 152(4): 371-80, 1982.
Artículo en Inglés | MEDLINE | ID: mdl-7165119

RESUMEN

Investigations were performed on the gastrocnemius muscle in 27 human fetuses aged 9-32 weeks, 2 fetuses of 74 and 220 C.-R. length were examined electron microscopically. The first muscle spindles were observed at 11 and 12 weeks and were covered by a capsule composed of single layer of cells. The intrafusal fibers, being in myotube stage, contained well developed regular actin as well as myosin filaments. Among the myotube cells interdigitating myoblasts are observed. Well developed sensory nerve endings covered by a basal lamina were found in the sockets on the surface of the intrafusal fibers. During the further stages of development an increase in diameter and number of intrafusal fibers have been noted. The capsule was composed of several layers. However, the inner and outer layers of the capsule consisted of cells resembling those of the perineurium. Within the muscle spindles satellite cells were observed. The results of these investigations have shown that the muscle spindles are established early in the fetal period. Furthermore, it was found that the development of muscle proprioceptors was not finished before birth.


Asunto(s)
Feto/citología , Mecanorreceptores/ultraestructura , Músculos/inervación , Humanos , Microscopía Electrónica , Músculos/ultraestructura , Miofibrillas/ultraestructura
18.
N Engl J Med ; 297(2): 119, 1977 Jul 14.
Artículo en Inglés | MEDLINE | ID: mdl-865578
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