1,133 research outputs found
Diffraction and an infrared finite gluon propagator
We discuss some phenomenological applications of an infrared finite gluon
propagator characterized by a dynamically generated gluon mass. In particular
we compute the effect of the dynamical gluon mass on and
diffractive scattering. We also show how the data on photoproduction
and hadronic reactions can be derived from the and
forward scattering amplitudes by assuming vector meson dominance and
the additive quark model.Comment: 4 pages, 7 figures, added references and figures, changed structure.
Contribution to Proceedings of XVIIIth Reuniao de Trabalho sobre Interacoes
Hadronicas, Sao Paulo, Brazil, 22-24 May, 200
Diversity of herbaceous forage species as sustainability indicator in Kenyan Rangeland.
Rangelands in Kenya make up for 70% of the land and hosts 60% of its livestock population. This ecosystem is largely inhabited by nomadic pastoralists whose livelihood depents on livestock. Land subdivision, population growth, climate change, devastating droughts, land degradation and unsustainable land use practices threaten the future of pastoralist and wildlife conservation in the rangelands. Knowledge about diversity of species is an important indicator of degraded land in the rangelands. Monitoring forage species can be a way to help livestock owning communities and farmers to recover degraded land and improve the natural environment. This study aimed to identify main herbaceous species present in nomadic pastoralist and farm rangelands in Kenya. This trial was conducted during the wet season in 2012. Two different environments were visited during a research expedition. Ol Maisor a commercial ranch that has been utilizing Holistic Management for the past years is located in Laikipia County. The second one being in Merti, Isiolo County composed of four sites: Bisan Biliquo, Bulesa, Korbesa and Malkagalla and being managed by the Merti Grazing Committee, a nomadic pastoralist community. Five randomly selected sites were visited in Ol Maisor and twelve sites in Merti. All sites were identified by GPS and their coordinates recorded. In each site, plants were collected to make exsiccates using traditional techniques (by press). Botanic characterization was done by identification of family, genus and species at the Herbarium of the Kenya Agricultural Research Institute (KARI) in Kiboko. At Ol Maisor Ranch the dominant family found was Poaceae (grasses). This family represents the most important species for grazing lands in Kenya indicating good and healthy rangelands. It was possible to identify 51 different grass species at Ol Maisor Ranch. At least, 13 genera were identified at least seven to eight times in this location: Aristida, Bothrichloa, Cenchrus, Cynodon, Digitaria, Eragrostis, Harpchne, Panicum, Paspalum, Pennisetum, Setaria, Themeda, Trachypogon. Eragrostis tenuiflora was the most abundant species. This grass is a poor constituent of pasture once livestock prefers other more palatable species when it is available. In Merti, forb were identified as more than 50% of the botanic pasture composition. The total number of species found were 67. At least ten different botanic families were present in this region: Acanthaceae, Amaranthaceae, Combretaceae, Fabaceae, Labiatae, Liliaceae, Malvaceae, Onagraceae, Poaceae, Polygonaceae and Sollanaceae. It was possible to identify 11 genera of grasses: Aristida, Cenchrus, Chloris, Cyprus, Digitaria, Eleusine, Eragrostis, Hyperenia, Panicum, Sehima, Tetrapogon. The most frequent genus was Eragrostis. Among the forb only three genera were important: Sida, Barelia and Ocimum. Two of these can be used as indicator of degraded lands and they were present in large areas. In Merti the observed biodiversity shows a potential for various livestock species other than cattle such as sheep, goats and other ruminants to use the land for grazing, Ol Maisor?s rangeland is more appropriate for cattle grazing, but it is necessary to monitor some of the less palatable species found in large density and the possibility to substitute it with better grass species. In both places a good biodiversity could be identified, however, it is necessary to carry out annual monitoring in order to keep weeds under control in the Kenyan rangelands
Evaluation degree of degraded rangeland on grazing communities in Kenya.
Most of 80% of Kenya´s land is categorized as arid and semi-arid. Agropastoralism and pastoralism based on livestock production serve as the bedrock of site livelihoods and culture. Pastoralists? livelihoods are affected by frequent and severe droughts, growing demographic pressure and conflicts over natural resource utilization. Vulnerability worsened by accessible grazing lands is often mismanaged and either overgrazed or underutilized leading to land degradation. This work aimed to develop a score index to classify degraded land degree to help technician and pastoralist in adequate use of tools to recovery degraded lands. This trial was conducted using participatory research with four grazing communities (Bisan Biliquo, Bulesa, Korbesa and Malkagalla) in Kenyan dry land from May 2011 to November 2012. There were characterized three sites in each community. First of all, a general characterization was made. In this first characterization were collected information about soil, plant, land use, water source distance and wildlife. Based on this information was chosen spots to make monitoring rangeland on each site. Transect method was used to collect information about bare ground (%), plant cover(%), plant height(cm), number of species(unit), biomass(kg) and litter (kg) production. A practical sheet from Mpala Institute was used to collect data on field. These five parameters were chosen because it was easier to collect by technician and pastoralist. Each parameter was classified in categories according type of measure (%, kg or cm) and could be analyzed and received a grade between 0 and 5. From summing the grades a score index was created to classify stage of degraded land. Five categories were made: 1-6 grades meant high degraded land; 7-12 degraded rangeland; 13-18 recovery rangeland; 19-24 good rangeland and 25-30 healthy rangeland. None of the sites got good or healthy rangeland. In fact all these areas are included in a program to recovering degraded land. The best situation was found in Bulesa where most of areas were classified as recovery land. In this case was recommended to reduce grazing pressure in order to improve litter production. Korbesa place second and was classified as recovery land. It was recommended basically management adjustment for improve biomass production. Bisan Biliquo areas were classified as high or degraded and needed some interventions on management level. In one spot and reseeding was recommended in the two others. Malkagalla was the worse scored site and presented the worse condition rangeland. All spots monitored were classified as high degraded land. Management intervention in this place should be directed to recover biodiversity by reseeding native species and improve biomass production Based on this was highly recommended exclude animal grazing during a period of time. Tools to monitoring rangeland and support diagnostic for degraded lands can be useful to identify problems and propose solutions to recovery degraded lands in dry rangelands
Efeitos de níveis de adubação sobre cultivares de milho (Zea mays L.) em monocultivo e em consórcio com o feijão (Phaseolus vulgaris L.).
Galactic or extragalactic chemical tagging for NGC 3201?: Discovery of an anomalous CN-CH relation
The origin of the globular cluster (GC) NGC 3201 is under debate. Its retrograde orbit points to an extragalactic origin, but no further chemical evidence supports this idea. Light-element chemical abundances are useful to tag GCs and can be used to shed light on this discussion. Aims. Recently it was shown that the CN and CH indices are useful to identify GCs that are anomalous to those typically found in the Milky Way. A possible origin of anomalous clusters is the merger of two GCs and/or the nucleus of a dwarf galaxy. We aim to derive CN and CH band strengths for red giant stars in NGC3201 and compare these with photometric indices and high-resolution spectroscopy and discuss in the context of GC chemical tagging. Methods. We measure molecular band indices of S(3839) and G4300 for CN and CH, respectively from low-resolution spectra of red giant stars. Gravity and temperature effects are removed. Photometric indices are used to indicate further chemical information on C+N+O or s-process element abundances that are not derived from low-resolution spectra. Results. We found three groups in the CN-CH distribution. A main sequence (S1), a secondary less-populated sequence (S2), and a group of peculiar (pec) CN-weak and CH-weak stars, one of which was previously known. The three groups seem to have different C+N+O and/or s-process element abundances, to be confirmed by high-resolution spectroscopy. These are typical characteristics of anomalous GCs. The CN distribution of NGC 3201 is quadrimodal, which is more common in anomalous clusters. However, NGC 3201 does not belong to the trend of anomalous GCs in the mass-size relation. Conclusions. The globular cluster NGC 3201 shows signs that it can be chemically tagged as anomalous: it has an unusual CN-CH relation, indications that pec-S1-S2 is an increasing sequence of C+N+O or s-process element abundances, and a multi-modal CN distribution that seems to correlate with s-process element abundances. The non-anomalous characteristics are that it has a debatable Fe-spread and it does not follow the trend of mass size of all anomalous clusters. Three scenarios are postulated here: (i) if the sequence pec-S1-S2 has increasing C+N+O and s-process element abundances, NGC 3201 would be the first anomalous GC outside of the mass-size relation; (ii) if the abundances are almost constant, NGC 3201 would be the first non-anomalous GC with multiple CN-CH anti-correlation groups; or (iii) it would be the first anomalous GC without variations in C+N+O and s-process element abundances. In all cases, the definition of anomalous clusters and the scenario in which they have an extragalactic origin must be revised.Fil: Dias, B.. European Southern Observatory Chile.; ChileFil: Araya, I.. Universidad de Valparaiso; ChileFil: Nogueira-Cavalcante, J. P.. Observatorio Do Valongo; Brasil. Universidade Federal do Rio de Janeiro; BrasilFil: Saker, Leila Yamila. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Shokry, A.. European Southern Observatory Chile.; Chil
Effects of industrial cashew nut processing on anacardic acid content and allergen recognition by IgE.
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Estabilidade e adaptabilidade da produtividade de feijão caupi no Estado do Tocantins.
O trabalho teve por objetivo avaliar a adaptabilidade e a estabilidade produtiva de genótipos de feijão-caupi no Estado do Tocantins. Os dados desse trabalho foram obtidos de quatro experimentos, conduzidos nas regiões norte e centro-sul do Estado do Tocantins. Foram observadas diferenças significativas na interação genótipo vs locais para a característica produtividade média de grãos (ton. ha-1), evidenciando a existência de variabilidade entre genótipos. A produtividade variou de 1.120,8 a 2.727,5 ton. ha-1, destacando-se como a mais produtiva a cultivar BRS-TUCUMAQUE.CONAC 2012. Disponível em: http://www.conac2012.org/resumos/pdf/233a.pdf. Acesso em: 07 ago. 2013
Epidemiologia participativa para avaliação sanitária em rebanhos bovinos de assentamentos rurais e pequenas comunidades.
As doenças animais respondem as formas que assumem a produção, adquirindo diferentes significados de acordo com os valores culturais das várias comunidades e ao estágio de desenvolvimento da pecuária do local. Entretanto, são poucos os estudos que, a partir dos sujeitos sociais e de suas representações, avaliam e questionam o sistema, os serviços e as práticas, apesar de que reconhecidamente as abordagens epidemiológicas quantitativas e qualitativa se complementem. Visando investigar a incidência sazonal de doenças e problemas que afetavam o rebanho bovino e fatores de risco para enfermidades relacionadas à esfera reprodutiva em quatro assentamentos rurais do município de Corumbá foi utilizada uma associação de metodologias qualitativas de diagnóstico participativo, como a elaboração de um calendário sazonal associado a uma matriz de escores. Foram realizadas 4 dinâmicas grupais, por meio de reuniões com produtores dos assentamentos Taquaral, Tamarineiro, Paiolzinho e Mato Grande. As reuniões tiveram a participação, em média, de 14 assentados por assentamento e contaram com a participação de um facilitador treinado e colaboradores que anotavam as informações levantadas. Pelos resultados obtidos conclui-se que os calendários sazonais são métodos úteis para levantamentos preliminares de demandas e percepções dos produtores quando as doenças e problemas do seu rebanho.Disponível também em: Cadernos de Agroecologia, V. 5, n.1, 2010
Fertirrigação nitrogenada para produção de macieiras Eva e Princesa em Petrolina-PE.
O presente trabalho foi desenvolvido com o objetivo de avaliar produção de frutos das 26 macieiras ?Eva? e ?Princesa?, em função a fertirrigação nitrogenada em Petrolina-PE
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