Herbicide Selectivity In The Early Development Of Alexander Palm And Peach Palm

Herbicides are an efficient weed-control method, and herbicide selectivity with regard to palm species is an important subject of agricultural research. Owing to a lack of studies in the literature regarding the use of herbicides on palm trees, especially during the early stages of growth, the present study aimed to evaluate the selectivity of some herbicides during the early development of Alexander palm (Archontophoenix alexandrae) and peach palm (Bactris gasipaes) seedlings. The study was conducted in two seasons in a completely randomized design with eight treatments and four repetitions. The herbicide treatments and dosages (g i.a. ha-1), were as follows: fluazifop-p-butyl (93.8), sethoxydim (184.0), quizalofop-p-ethyl (75.0) clethodim + fenoxaprop-p-ethyl (50.0 + 50.0), fomesafen (225.0), lactofen (168.0), and nicosulfuron (50.0), and a no-herbicide control was included. The seedlings of both types of trees were transplanted into 3.1-L plastic containers. In the first study, herbicide was applied to Alexander palm seedlings of 25-30 cm in height. In the second study, herbicide was applied to Alexander palm seedlings of 30-40 cm in height. Herbicide was applied to peach palm tree seedlings of 40-55 cm in height in both studies. In peach palms only, the herbicides caused slight visible damage during early development. Collectively, the results suggested that all herbicides used are selective and can be used on peach palms during the various stages of development when there are one to four leaves. For Alexander palms, fluazifop-p-butyl, quizalofop-p-ethyl, and lactofen were the only herbicides that did not affect early development during the stages when the plant had one to four leaves.3752891290

Periods Of Weed Interference In Maize Crops Cultivated In The First And Second Cycles

The interference of weeds in maize production may be reflected in grain yield losses that vary as a function of the density, stage and degree of aggressiveness of the species present. In the agricultural ecosystem, crops and weeds demand light, water, nutrients and space, which are frequently not available in sufficient quantities, leading to competition. The aim of this work was to determine the period of interference of weed plants, in particular of naked crabgrass (Digitaria nuda) on maize crop in the first and second harvest. The treatments were defined as increasing periods of coexistence and increasing control of weed community (7, 14, 21, 28, 35, 42, 49, and 56 days), two more controls, a control including one with weed control until the end of the culture cycle and another with coexistence until the harvest. For each period, were evaluated the stand of maize plants, length of ear, number of grains per row, number of rows per ear, cob, 100-grain weight, and grain productivity. The data obtained were subjected to analysis of variance using the F test, with average treatments compared using Tukey's test at 5% probability. Crop productivity was evaluated by means of regressions, the critical periods of interference were estimated. The critical timing of weed removal was 25 days for both harvests. The critical weed free period was 54 and 27 days for the first and second harvest respectively. For the conditions of the first and second harvest, the critical period of weed control was of 29 and 2 days respectively.3752867287

Antecedent use of fluoroquinolones is associated with resistance to moxifloxacin in Clostridium difficile

ObjectiveMoxifloxacin is characterized by high activity against Gram-positive cocci and some Gram-positive and -negative anaerobes, including Clostridium difficile. This study investigates the role of prior quinolone use in relation to patterns of susceptibility of C. difficile to moxifloxacin.MethodsSixty-three clinical isolates of C. difficile were investigated for toxigenicity, susceptibility to moxifloxacin, and mutations in the DNA gyrase gene. The medical histories for 50 of these patients were available and used to identify previous fluoroquinolone use.ResultsThirty-three (52.4%) strains showed resistance to moxifloxacin (MICs ≥ 16 mg/L). All moxifloxacin-resistant strains harbored a mutation at amino acid codon Ser-83 of gyrA. Forty-five isolates (71.4%) were toxigenic; all moxifloxacin-resistant strains were in this group. Resistance to moxifloxacin was associated with prior use of fluoroquinolones (P-value 0.009, chi-square).ConclusionsAlthough the use of moxifloxacin to treat C. difficile-associated diarrhea is not likely to be common, these data show a relationship between antecedent fluoroquinolone use and resistance to moxifloxacin in C. difficile isolates, and raise questions regarding selection pressure for resistance placed on colonizing bacteria exposed to fluoroquinolones. Mutations in gyrA are involved in moxifloxacin resistance

OBTENÇÃO E CARACTERIZAÇÃO DE NANOPARTÍCULAS DE PLGA PARA VEICULAÇÃO INTRAVENOSA DE PROTEÍNAS

O desenvolvimento de nanopartículas é considerado atualmente um sistema promissor para o carreamento de drogas em sítios específicos. O uso de polímeros na obtenção desse sistema pode ser de origem natural ou sintética desde que seja biocompatível ou biodegradável. Desenvolver sistemas de transportes para carrear proteínas requer cuidado com variáveis como tempo de homogeneização e concentração do surfactante, que interferem diretamente na obtenção destas. As nanopartículas foram obtidas pelo método de dupla emulsificação, onde foram elaborados 6 sistemas (A,B,C,D,E e F), utilizando diferentes concentrações de PVA (0,5; 1 e 1,5%) e tempo de homogeneização de 30 e 60 segundos. Os sistemas foram analisados pela técnica de espalhamento de luz dinâmico. Os resultados mostraram que o sistema D apresentou melhor IPD com 0,638, com tamanho de partícula de 678,3 nm, o que sugere homogeneidade maior em relação aos outros sistemas. Porém, há a necessidade de se otimizar o método para obtenção de partículas de tamanhos menores para a veiculação intravenosa

Observational constraint on generalized Chaplygin gas model

We investigate observational constraints on the generalized Chaplygin gas (GCG) model as the unification of dark matter and dark energy from the latest observational data: the Union SNe Ia data, the observational Hubble data, the SDSS baryon acoustic peak and the five-year WMAP shift parameter. It is obtained that the best fit values of the GCG model parameters with their confidence level are $A_{s}=0.73^{+0.06}_{-0.06}$ ($1\sigma$) $^{+0.09}_{-0.09}$ $(2\sigma)$, $\alpha=-0.09^{+0.15}_{-0.12}$ ($1\sigma$) $^{+0.26}_{-0.19}$ $(2\sigma)$. Furthermore in this model, we can see that the evolution of equation of state (EOS) for dark energy is similar to quiessence, and its current best-fit value is $w_{0de}=-0.96$ with the $1\sigma$ confidence level $-0.91\geq w_{0de}\geq-1.00$.Comment: 9 pages, 5 figure

Spectroscopy studies of 4H-SiC

Calculations of the total dielectric functions and the optical bandgap energy (OBGE) of 4HSiC were performed by the full-potential linear muffin-tin-orbital method. The results are compared to spectroscopic ellipsometry dielectric measurements agreeing closely over in a wide range of energies. The obtained theoretical value of the (OBGE) agrees very closely with the measured ones obtained by transmission and photoacoustic spectroscopies at room temperature performed on 470 µm thick wafer and a 25 µm thick homoepitaxial layer of 4H-SiC samples grown (n-type, Siface) by hot wall CVD