696 research outputs found
Seasonality of Growth in Grass-Clover Swards Under Repetitive Nitrogen Application
The cohabitation of grass and clover is possibly due to asynchrony in their growth patterns, and to the beneficial effects of fixed nitrogen (N) on grass. Incompatibility of clover persistence with N fertilisation has been frequently reported (Nassiri and Elgersma, 2002). However, limited information is available regarding the effect of repetitive application of N in mixed swards. This research aims to study the balance between species in response to application of increasing rates of N throughout the growing season
Modelling the Effect of a Variable Light Extinction Coefficient and Leaf Dispersion on Light Partitioning Between Species in a Grass-Clover Mixture
Light partitioning in a grass-clover mixture was studied using a general competition model. The model assumes a fixed extinction coefficient (k) and no leaf dispersion. This was compared with modelling the effect of different k of both species over height as well as the effect of type of leaf dispersion. These new assumptions led to a better estimation of the light partitioning between both species. For grass the effect of variable k and leaf dispersion was similar and in both cases the total absorbed light was lower than under default conditions. For clover the new assumptions led to a higher absorbed radiation than in the original model. However, in this case the effect of leaf dispersion was more important
RF System Upgrades to the Advanced Photon Source Linear Accelerator in Support of the Fel Operation
The S-band linear accelerator, which was built to be the source of particles
and the front end of the Advanced Photon Source injector, is now also being
used to support a low-energy undulator test line (LEUTL) and to drive a
free-electron laser (FEL). The more severe rf stability requirements of the FEL
have resulted in an effort to identify sources of phase and amplitude
instability and implement corresponding upgrades to the rf generation chain and
the measurement system. Test data and improvements implemented and planned are
describedComment: LC 2000 (3 pages, 6 figures
Analytical and Numerical Investigation of Tube Compression with a Multi-Turn, Axisymmetric Coil
While some Finite Element software packages exist that are capable of modelling the
electromagnetic forming process and estimating the corresponding process parameters
(e.g., magnetic pressure and workpiece velocity), there is a lack of simplified and accuracy
analytical modelling tools for this purpose. In this study, a coupled analytical model was
created to predict the magnetic pressure generated by a multi-turn, axisymmetric coil and
the corresponding tube radial displacement and velocity. In the proposed model, at each
time increment, the magnetic field geometry is updated in response to the tube deformation.
To assess the proposed analytical model, numerical simulations were conducted where the
pressure distribution from the analytical model was applied. The results show good
agreement between analytical and numerical results
Oscillatory Photodynamic Therapy for Choroidal Neovascularization and Central Serous Retinopathy; a Pilot Study
Purpose: To report the preliminary results of oscillatory photodynamic therapy (OPDT) for choroidal neovascularization (CNV) and central serous retinopathy (CSR). Methods: This study included 7 eyes of 6 patients with CSR (2 eyes), idiopathic CNV (2 eyes), CNV due to age-related macular degeneration (AMD) (2 eyes), and peripapillary CNV secondary to presumed ocular histoplasmosis syndrome (1 eye). Intravenous verteporfin (6 mg/m2 body surface area) was infused over 10 minutes followed by oscillating laser (wavelength 689 nm) covering slightly beyond the entire lesion. An Area Centralis lens was applied and laser was delivered (600 mW/cm2 fluence rate and 50 J/cm2 dose). Intravitreal bevacizumab and dexamethasone combination therapy was used with OPDT in 4 eyes with CNV; intravitreal dexamethasone and triamcinolone acetonide were injected in the other eye with CNV. Clinical examination, funduscopy, fluorescein angiography, and optical coherence tomography (OCT) were performed at baseline and after treatment. Results: After mean follow-up of 7.1±5.1 months, visual acuity improved from 0.87±0.69 logMAR (20/160) to 0.60±0.65 logMAR (20/80) (P = 0.027); central foveal thickness decreased from 322±62.1 to 240.7±34.8 microns as measured by OCT (P = 0.018). Fluorescein angiography and OCT demonstrated cessation of vascular leakage, and resolution of hemorrhage and subretinal fluid in all eyes. No adverse events or recurrence were noted. Conclusion: OPDT was effective in treating CNV lesions and CSR. OPDT may be an improvement on standard PDT due to reduced side effects, thermal damage and scarring
Testing and Implementation Progress on the Advanced Photon Source (APS) Linear Accelerator (Linac) High-Power S-band Switching System
An S-band linear accelerator is the source of particles and the front end of
the Advanced Photon Source injector. In addition, it supports a low-energy
undulator test line (LEUTL) and drives a free-electron laser (FEL). A
waveguide-switching and distribution system is now under construction. The
system configuration was revised to be consistent with the recent change to
electron-only operation. There are now six modulator-klystron subsystems, two
of which are being configured to act as hot spares for two S-band transmitters
each, so that no single failure will prevent injector operation. The two
subsystems are also used to support additional LEUTL capabilities and off-line
testing. Design considerations for the waveguide-switching subsystem, topology
selection, control and protection provisions, high-power test results, and
current status are describedComment: Linac 2000 paper No. THE07 3 pages with 3 figure
Simultaneous measurement of multiple Th1 and Th2 serum cytokines in psoriasis and correlation with disease severity.
BACKGROUND: Psoriatic plaques have been shown to contain increased levels of proinflammatory cytokines. Serum levels of interleukin (IL)-6, IL-7, IL-8, and interferon (IFN)-gamma have been reported elevated in psoriatic patients. AIM: To evaluate serum cytokine profiles in psoriasis patients by improved enzyme-linked immunosorbent assay (ELISA) technique and to correlate these levels with disease severity. METHODS: We analyzed single serum samples from 10 patients with active untreated psoriasis, two patients with active treated psoriasis, and five healthy volunteers for major T helper type 1 and T helper type 2 cytokines using the LINCOplex ELISA multi-analyte detection system that permits simultaneous detection of multiple cytokines from a single sample. The disease severity, including erythema, induration, scale, and surface area, was assessed. RESULTS: IFN-gamma was markedly elevated in all sera from psoriasis patients, 33.8 +/- 1.3 pg/ml (mean +/- standard error) versus 8 +/- 1.5 pg/ml for normal controls (p < 0.01), and positively correlated with all indices of disease severity (Spearman r > 0.6). IL-8 was also increased in psoriasis patients (24.4 +/- 1.8 pg/ml) versus normal controls (3.6 +/- 1.2 pg/ml) (p < 0.05) and positively correlated with the degree of erythema (Spearman r > 0.6). Mean IL-12 levels were decreased in sera from psoriasis patients (8.5 +/- 1.2 pg/ml) compared with normal controls (42.2 +/- 5.3 pg/ml) (p < 0.01). Also, serum IL-10 levels were below detection levels in psoriatics compared with controls (6.4 +/- 1.3 pg/ml). CONCLUSIONS: This new ELISA system allowed rapid and reliable detection of numerous cytokines in single serum samples from patients with psoriasis. We observed that IFN-gamma and IL-8 cytokines were elevated in psoriatics and correlated with parameters of disease severity while IL-10 and IL-12 were decreased
Principles of primary survey and resuscitation in cases of pediatric trauma
Trauma is a common cause of death and disability in children. Proper approach to pediatric trauma involves adherence to ABCDE sequence in the primary survey and resuscitation in order to promptly recognize and manage life-threatening conditions immediately. This readily reviewed sequence includes A: establishment and maintenance of a patent airway while maintaining cervical spine immobilization; B: evaluation of breathing, ventilation and oxygenation, immediate treatment of tension pneumothorax, open pneumothorax and massive hemothorax; C: evaluation and treatment of circulatory compromise and shock; D: Disability and Neurologic Status, assessment of signs of increased intracranial pressure and impending cerebral herniation; and E: Exposure while preventing hypothermia. Implementing these assessment and management priorities can result in more favorable outcomes. © 2015 Tehran University of Medical Sciences. All rights reserve
The Development of an Empirical Model for Estimation of the Sensitivity to Heat Stress in the Outdoor Workers at Risk
Background: Workers who work in hot environments may be at risk for heat stress. Exposure to heat can result in occupational illnesses, including heat stroke, heat cramps, and heat exhaustion. The risk of exposure to heat depends on individual, environmental, and occupational risk factors. Individual risk factors may decrease the individual’s tolerance to heat stress. Sensitivity as an intrinsic factor may predispose a person to heat stress. Aim: This study was aimed to determine the criteria for sensitivity parameter, specify their weights using the fuzzy Delphi-analytical hierarchy, and finally providing a model to estimate sensitivity. The significant of the study is presenting a model to estimate the sensitivity to heat stress. Materials and Methods: The expert’s opinions were used to extract the criteria in Delphi method. After determining the weight of each criterion, Fuzzy analytic hierarchy Process (FAHP), by mathematical principles matrix and triangular fuzzy numbers, was applied for the prioritization of criteria. Results: According to experts’ viewpoints and considering some exclusion, 10 of 36 criteria were selected. Among 10 selected criteria, age had the highest percentage of responses (90% (27/30)) and its relative weight was 0.063. After age, the highest percentages of response were assigned to the factors of preexisting disease (66.6% (20/30)), body mass index (56.6% (17/30)), work experience (53.3% (16/30)), and clothing (40% (16/30)), respectively. Other effective criteria on sensitivity were metabolic rate, daily water consumption, smoking habits, drugs that interfere with the thermoregulatory processes, and exposure to other harmful agents. Conclusions: Eventually, based on the criteria, a model for estimation of the workers’ sensitivity to heat stress was presented for the first time, by which the sensitivity is estimated in percent.Keywords: Heat stress, Sensitivity, Personal factors, Fuzzy AH
Histiocytic Sarcoma Associated with Coombs Negative Acute Hemolytic Anemia: A Rare Presentation
Histiocytic sarcoma (HS) rarely involves extranodal sites, such as the spleen. We report a unique pediatric case of massive splenomegaly and refractory Coombs negative hemolytic anemia (CNHA) secondary to HS. The CNHA resolved completely after an emergent splenectomy. Next generation sequencing (NGS) revealed novel ASXL1, PTPN11, KIT, and TP53 mutations, unmasking a clonal heterogeneity within the same neoplasm
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