1,966 research outputs found
The muonic longitudinal shower profiles at production
In this paper the longitudinal profile of muon production along the shower
axis is studied. The characteristics of this distribution is investigated for
different primary masses, zenith angles, primary energies, and different high
energy hadronic models. It is found that the shape of this distribution
displays universal features similarly to what is known for the electromagnetic
profile. The relation between the muon production distribution and the
longitudinal electromagnetic evolution is also discussed
The average longitudinal air shower profile: exploring the shape information
The shape of the extensive air shower (EAS) longitudinal profile contains information about the nature of the primary cosmic ray. However, with the current detection capabilities, the assessment of this quantity in an event-by-event basis is still very challenging. In this work we show that the average longitudinal profile can be used to characterise the average behaviour of high energy cosmic rays. Using the concept of universal shower profile it is possible to describe the shape of the average profile in terms of two variables, which can be already measured by the current experiments. These variables present sensitivity to both average primary mass composition and to hadronic interaction properties in shower development. We demonstrate that the shape of the average muon production depth profile can be explored in the same way as the electromagnetic profile having a higher power of discrimination for the state of the art hadronic interaction models. The combination of the shape variables of both profiles provides a new powerful test to the existing hadronic interaction models, and may also provide important hints about multi-particle production at the highest energies.Peer Reviewe
Platelet-Derived Growth Factor Preserves Retinal Synapses in a Rat Model of Ocular Hypertension.
PURPOSE: Platelet-derived growth factor (PDGF) promotes neuronal survival in experimental glaucoma and recruits glial cells that regulate synapses. We investigated the effects of intravitreal PDGF on the inflammatory milieu and retinal synapses in the presence of raised IOP. METHODS: Animals with laser-induced IOP elevation received intravitreal injections of either saline or 1.5 μg PDGF. At 7 days, a further intravitreal injection was administered so groups received "PDGF-saline" (n = 15), "PDGF-PDGF" (n = 13), or "saline-saline" (n = 20). Platelet-derived growth factor receptor activation was assessed after 2 weeks using Western blot for PI3 kinase. Immunohistochemistry was performed for markers of synapses in the inner plexiform layer (IPL): PSD-95, GluR1, SY38; RGCs: βIII-tubulin, and glial cells: Iba-1, CD45. Real-time quantitative polymerase chain reaction (qPCR) was performed for Arc, selp, MCP-1, IL-6, IL-10, and CX3CR1 (n = 13). RESULTS: A single injection of PDGF increased IPL synaptic density in high IOP eyes (PSD-95 = 8.65 ± 0.43, SY38 = 8.68 ± 0.51, GluR1 = 9.03 ± 0.60 puncta/μm3, P < 0.001) and expression of synaptic modulator Arc (6.92 ± 3.71-fold change/control, P < 0.05) in comparison with vehicle (PSD-95 = 4.59 ± 0.41, SY38 = 4.46 ± 0.38, GluR1 = 5.94 ± 0.50 puncta/μm3, Arc = 1.46 ± 0.31-fold/control). This was associated with more resident microglia (8.16 ± 1.34-fold change/control, P < 0.001) and infiltrating monocyte-derived macrophages in the retina as well as increased Selp expression (26.8 ± 14.12-fold change/control, P < 0.05). Optic nerve head (ONH) showed an increased microglia (saline = 1.44 ± 0.13 versus PDGF = 2.23 ± 0.18-fold change/control, P < 0.01) but not infiltrating macrophages. IL-10 expression was significantly increased in PDGF-treated eyes (5.43 ± 0.47-fold change/control, P < 0.05) relative to vehicle (2.51 ± 0.67-fold change/control). CONCLUSIONS: Platelet-derived growth factor increased microglial and monocyte-derived macrophage populations in the eye and protected intraretinal synapses from degeneration in our experimental glaucoma model.Supported by the Agency for Science Technology and Research Singapore (RC), the Cambridge Eye Trust, the HB Allen Charitable Trust and the Jukes Glaucoma Research Fund, and by Grant 1868 from Fight for Sight (KM).This is the final version of the article. It first appeared from the Association for Research in Vision and Opthalmology via http://dx.doi.org/10.1167/iovs.15-1786
Bananeiras e plátanos em sistemas agroflorestais do Baixo Sul da Bahia.
As características socioeconômicas, ambientais e culturais do Baixo Sul da Bahia permitiram o desenvolvimento e a expansão de sistemas integrados de produção, com destaque para os sistemas agroflorestais. Bananeiras e plátanos são culturas agrícolas comuns na maioria dos arranjos produtivos de sistemas agroflorestais encontrados nessa região
Conteúdo de noradrenalina do hipotálamo e tronco-encefálico de ratos inoculados com Trypanosoma Cruzi
Noradrenaline was assayed fluorimetrically in the hypothalamus and brainstem of rats killed 20 and 32 days after inoculation with the Y strain of T. cruzi (300,000 trypomastigotes i.p.). In these animals and their normal controls the right atrial appendages were submitted to the glyoxilic acid fluorescence technique for the demonstration of noradrenergic nerves. The noradrenaline content of the brain-stem and hypothalamus of the infected animals was not significantly different from that of controls. In the atrial appendages, however, an almost complete noradrenergic denervation was observed. This result indicates that the mechanism involved in neuronal lesion in Chagas'disease discriminates between peripheral and central noradrenergic neurons.O conteúdo de noradrenalina do hipotálamo e do tronco encefálico de ratos controle e inoculados com a cepa Y (300.000 tripomastigotas, i.p.) de Trypanosoma cruzi foi medido pela técnica fluorimétrica de Anton e Sayre. Os animais foram sacrificados 20 e 32 dias depois da inoculação. Para avaliação do grau de desnervação simpática do coração dos animais infectados, a aurícula direita foi observada com microscópio de fluorescência após tratamento histoquímieo pela técnica do ácido glioxílico. O conteúdo de noradrenalina do hipotálamo e do tronco encefálico dos animais infectados não diferiu do medido nos animais controle. Contudo, um quase completo desaparecimento das fibras adrenérgicas foi observado no coração dos animais chagásicos, sugerindo que o mechanismo envolvido na lesão discrimina neurônios adrenérgicos centrais e periféricos
Qualidade de "SEEDLINGS" de umbuzeiro (Spondias tuberosa) em função de farelo de mamona no substratado de propagação.
Qualidade de seedlings de umbuzeiro (Spondias tuberosa) em função de farelo de mamona no substratato de propagação.
O umbuzeiro (Spondias tuberosa Arruda Câmara) é uma frutífera nativa da região Nordeste do Brasil, representando fonte de emprego e renda no período da safra, para as populações na área de ocorrência natural das plantas. Estudos indicam que o uso racional de farelo de mamona poderá disponibilizar às plantas quantidades suficiente de nutrientes, dispensando o uso complementar de fertilizante mineral, em especial os nitrogenados
Efeito de níveis de sombreamento no conteúdo de clorofila foliar e na área foliar específica de cultivares de bananeira.
A fonte de energia que as plantas verdes utilizam é a energia solar, e as características da folha influenciam muito no aproveitamento da luz, especialmente em condições competitivas. Nos sistemas agroflorestais (SAFs), que é um tipo de policultivo, onde espécies agrícolas e ou animais são exploradas em associação com espécies arbóreas lenhosas, a disponibilidade de radiação solar pode ser limitante para o crescimento de algumas espécies
Evaluation of local thermal discomfort in a classroom equipped with cross flow ventilation
This paper presents an evaluation of the local thermal discomfort level in a classroom equipped with cross ventilation, for a typical moderate summer day in Portugal. Three different ventilation configurations based on window and door opening were considered. In each, the thermal comfort, air quality and acoustical comfort conditions were also evaluated. This experimental study was made in the South of Portugal, exposed to a Mediterranean climate. Thermal comfort was based on the PMV index, the air quality was based on the air renovation rate and acoustical comfort levels were based on the reverberation time, voice clarity, definition and early reflection ratio. The detailed local thermal discomfort analysis was based on draught risk and uncomfortable air velocity fluctuations. Other measurements included relative humidity, the radiative mean temperature, carbon dioxide concentration (tracer gas decay), and noise level decay of impulsive response. Results showed that for the warmest of weather open windows and classroom door gave the best air quality and comfort conditions
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