Tillering dynamics in Guinea grass pastures subjected to management strategies under rotational grazing

This study was carried out to analyze the tillering profile of Guinea grass (Panicum maximum cv. Tanzania) pastures subjected to two grazing frequencies (time necessary to intercept 90 and 95% of the incoming light) and two post-grazing heights (30 and 50 cm) in the period from November 2005 to October 2006. The experimental design was of completely randomized blocks with three replications, in a 2 × 2 factorial arrangement. At the end of the spring, pastures managed with 90% light interception showed greater tiller appearance rates in relation to pastures managed with 95%, regardless of post-grazing height. In the summer and fall, pastures managed with post-grazing height of 30 cm showed higher tiller appearance rates in comparison with pastures managed at 50 cm, regardless of grazing frequency. Concerning the tiller mortality rates, in the summer, higher values were found for pastures managed at 90/50 and 95/30 (interception/height), intermediate values at 90/30 and lower values in those managed at 95/50. Pastures managed at 90/30, 95/30 and 95/50 in the fall presented greater tiller mortality rates than those managed at 90/50. These differences do not occur in the winter/beginning of spring. The stability index remained above 1 all through the experimental period. All management strategies evaluated are adequate for Guinea grass.

The potentiation of the histamine release induced by adenosine in mast cells from guinea pig lung and heart: Sharp dependence on the time of preincubation

We studied here the effect of a wide range of adenosine concentration and time of preincubation, on the histamine release induced in the guinea pig mast cells by different stimulus. Adenosine (10(-5)-10(-3) M) potentiated the histamine release induced by antigen in the guinea pig heart (isolated and dispersed tissue) and lung mast cells but not induced by ionophore A23197. The potentiation caused by adenosine (10(-4) M) was maximum after 1-3 min of preincubation and is probably an extracellular effect since it was not avoided by dipyridamol (3 x 10(-7)-10(-6) M) that inhibit the uptake of adenosine. Similar potentiation was also produced by the adenosine mimetic 2-chloroadenosine (10(-5) M) and both effects were inhibited by 8-phenyltheophylline indicating an effect on the type A receptors. It is suggested that the adenosine potentiation may not be related to changes on the cyclic AMP levels. (C) 2000 Academic Press.

LH and FSH concentration and follicular development in Nellore heifers submitted to fixed-time artificial insemination protocols with different progesterone concentrations

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Productivity of lettuce and radish cultivations as a function of spacing and of time of establishment of intercropping

The experiment was conducted at UNESP, Jaboticabal-SP, during the period of September to November of 2000, with the objective of evaluating the productivity of the cultivation of lettuce and radishes as a function of spacing between plants and of the time of establishment of intercropping. The experimental design was a completely randomized blocks and four replications. The 14 treatments consisted of combinations of spacing between lines (0.30 and 0.40 m), cultivation systems (intercropping and monoculture), and time of sowing of radish seeds to establish intercropping (0, 7 and 14 days after transplant of lettuce). The cultivars of lettuce and radish were, 'Tainá' and 'Crimson Gigante', respectively. A greater yield of commercial radish roots was obtained with intercropping cultivation. The fresh mass of lettuce in monoculture did not differ from that produced with intercropping. These results suggest that intercropping cultivation between these species is advantageous.

Time-like and space-like pion form factors within front-form dynamics

An approach for a unified description of the pion electromagnetic form factor in the space- and time-like regions, within a constituent quark model on the light front is briefly illustrated. Three main ingredients enter our approach: i) the on-shell quark-hadron vertex functions in the valence sector, ii) the dressed photon vertex where a photon decays in a quark-antiquark pair, and iii) the emission and absorption amplitudes of a pion by a quark. © 2005 American Institute of Physics.

Phase space properties and chaotic transport for a particle moving in a time dependent step potential well

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Identification of Candida Spp. In Patients with Denture Stomatitis: Relationship with Gender, Age, Time of Denture use and Newton’s Classification

Epidemiological researches are important to understand the distribution and etiology of oral diseases. The actual researches that show the relationship between patient ages, denture status and denture stomatitis are scarce. So, the aim of this study was to identify of Candida spp. in patients with Denture Stomatitis (DS) and to correlate with gender, age, time of denture use and Newton’s classification. 204 complete denture patients (46 males and 158 females) were selected. DS was classified according to Newton’s classification and it was related to gender, age and time of denture use. Samples from the palatal mucosa and the surface of the upper denture of patients with DS were evaluated using PCR test for identification of Candida species. T-test, chisquare and Fisher’s exact tests were used for statistical analysis. DS was evidenced in 54.4% of the sample. According to gender 41.3% of the males and 58.3% females had the disease and the differences were statistically significant (p = 0.032). The type of DS was directly influenced by the time of denture use (p<0.001), but it was not significantly related to the age of the participants (p>0.05). C. albicans, C. tropicalis, C. glabrata, C. krusei and C. dubliniensis were identified by PCR test. DS is more prevalent in women and the prevalence of DS was influenced by the time of denture use (years). C. albicans was identified as the most frequent specie in patients with DS.

Color stability of a nanofilled resin: influence of polishing and finishing and fluoride solutions according to time

Aim: The aim of the study was evaluate the finishing and polishing effect of the color stability of the composite resin Filtek Supreme XT, according to different fluoride solutions and time. Material and Methods: Specimens were prepared (n=140) with half of the samples finished and polished. The experimental groups were divided according to the presence or absence of finishing and polishing and immersion solutions (artificial saliva, sodium fluoride solution at 0.05% - manipulated, Fluordent Reach, Oral B, Fluorgard). The specimens remained in artificial saliva for 24 hours and were subjected to an initial color analysis using a spectrophotometer CIELab system. Then, they were immersed in the experimental solutions for 1 minute a day. The readings of the color change were made after 24 and 48 hours, 7, 14, 21, 30 and 60 days after the first immersion. The three-way mixed Analysis of Variance (ANOVA) ("finishing/polishing", "immersion medium" and “time”) were performed. For multiple comparisons, the Sidak test for repeated measure was used, with a 5% level of significance. Results: The finishing and polishing factor showed significant variability, independently of the immersion media (p<0.001). Cconclusion: Finishing and polishing procedures yielded better color stability to composite resin over time, regardless of the immersion media.

Higher screen time is associated with overweight, poor dietary habits and physical inactivity in Brazilian adolescents, mainly among girls

To analyse the associations between high screen time and overweight, poor dietary habits and physical activity in adolescents according to sex. The study comprised 515 boys and 716 girls aged 14-17 years from Londrina, Brazil. Nutritional status (normal weight or overweight/obese) was assessed by calculating the body mass index. Eating habits and time spent in physical activity were reported using a questionnaire. The measurement of screen time considered the time spent watching television, using a computer and playing video games during a normal week. Associations between high screen time and dependent variables (nutritional status, eating habits and physical activity levels) were assessed by binary logistic regression, adjusted for sociodemographic and lifestyle variables. Most adolescents (93.8% of boys and 87.2% of girls) spent more than 2 hours per day in screen-time activities. After adjustments, an increasing trend in the prevalence of overweight and physical inactivity with increasing time spent on screen activities was observed for both sexes. Screen times of >4 hours/day compared with <2 hours/day were associated with physical inactivity, low consumption of vegetables and high consumption of sweets only in girls and the consumption of soft drinks in both sexes. The frequency of overweight and physical inactivity increased with increasing screen time in a trending manner and independently of the main confounders. The relationship between high screen time and poor eating habits was particularly relevant for adolescent girls.

Growth and body nutrient deposition of two broiler commercial genetic lines

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Economic analysis of cucumber and lettuce intercropping under greenhouse in the winter-spring

A análise econômica complementa a avaliação da eficiência dos cultivos consorciados, considerando além da produção física das culturas, o preço dos produtos segundo sua classificação qualitativa e época do ano. Avaliou-se economicamente consórcios de alface crespa e pepino, em duas populações de plantas, no inverno-primavera, em casa de vegetação, em Jaboticabal, SP, Brasil. Foram calculados o custo operacional total (COT), a receita bruta (RB) e o lucro operacional (LO) das culturas do pepino e alface em monocultura e em consórcio. A mão-de-obra foi a componente com maior participação no COT das culturas em consórcio e monocultura. Maiores RB e LO foram observadas nos cultivos consorciados estabelecidos com o transplante da alface e do pepino no mesmo dia, independente da densidade populacional. Considerando-se o lucro operacional e o índice de uso eficiente da área, recomenda-se o cultivo consorciado com transplante da alface até 10 dias após o transplante (DAT) do pepino, com duas linhas, e ao 0 DAT do pepino cultivado com uma linha no canteiro

Chilling Injury in Avocados and Its Prevention with Thermal Treatment

The combinations of temperature and time which can cause chilling injuries in avocados 'Geada', 'Quintal' and 'Fortuna' were determined. The binomial 4 degrees C/ 28 days was selected to determine the activity of peroxidase (POD), polyphenoloxidase (PPO), polygalacturonase (PG) and methylesterase pectin (PME). The respiratory activity was also evaluated. The fruits were stored at this condition until being transferred to ambient conditions (22 degrees C and 77% RH) until maturity, when they were compared to fruits stored permanently at this environment, after being cleaned (control). In the second part of this work, different hydrothermal treatments were tested to prevent or minimize chilling injuries. Avocados 'Geada', 'Quintal' and 'Fortuna' were treated at 38 degrees C for 0, 30, 60 and 90 minutes before storage at 4 degrees C for 28 days. It was observed that the activity of enzymes associated to browning, POD and PPO, and to maturation, PG and PME, had become greater in fruits stored at 4 degrees C, or when they were transferred to environmental conditions. Fruits subjected to refrigeration, after transferred to environment, presented lower respiratory peak intensity and it occurred earlier than the others. Treatments using 38 degrees C for 60 and 90 min minimized the symptoms of chilling injury in avocados 'Geada' while for 'Quintal' the most efficient was 38 degrees C for 60 min. In 'Fortuna' these treatments did not minimize the damage by cold.

Chemical and microbiological changes and aerobic stability of marandu grass silages after silo opening

Esta pesquisa foi realizada com os objetivos de caracterizar a microbiologia e avaliar a estabilidade aeróbia de silagens de capim-marandu contendo polpa cítrica peletizada (PCP). A forragem colhida foi submetida aos seguintes tratamentos: silagem de capim-marandu; silagem de capim-marandu + 5% PCP e silagem do capim-marandu + 10% de PCP com base na matéria natural. As alterações químicas e microbiológicas foram feitas aos 0, 2, 4 e 6 dias após a abertura dos silos (tambores de metal com 80 cm de altura e 50 cm de diâmetro). Na avaliação da estabilidade aeróbia por meio da alteração da temperatura, 3 kg de silagem foram colocados em caixas de isopor, que foram armazenadas em câmara climática. Nos dois ensaios realizados, utilizou-se delineamento inteiramente ao acaso com cinco repetições, em esquema de parcelas subdivididas, de modo que os níveis de PCP na silagem corresponderam às parcelas e o tempo, às subparcelas. As silagens sem polpa apresentaram desenvolvimento de bacilos e enterobactérias e aumento do pH no decorrer do desabastecimento dos silos. A presença de leveduras foi detectada nas silagens contendo o aditivo e aumentou do primeiro ao sexto dia de aeração. A digestibilidade in vitro da matéria seca (DIVMS) reduziu com o aumento dos tempos de aeração. A temperatura nas silagens com 10% de PCP aumentou durante a aerobiose. Com a abertura dos silos, as silagens apresentaram-se instáveis, seja pelo desenvolvimento de bactérias seja pelo desenvolvimento de leveduras, o que reduziu seu valor nutritivo.

Performance of supplemented heifers on Marandu grass pastures in the wet-to-dry transition and dry seasons

The objective of the present study was to evaluate the characteristics of the sward canopy of Marandu grass during the rainy season, the wet-to-dry transition and the dry seasons, between March and September 2004, under intermittent grazing, and to correlate those characteristics with the performance of crossbred heifers receiving mineral supplements ad libitum or protein supplements. The experiment consisted of a randomized block design with three blocks (set of 13 paddocks), each containing five crossbred heifers per experimental unit, totaling 15 replicates. The heifers were given protein supplements daily in individual stalls and received an average 4 g/kg/day of the supplement during the rainy season and 5 g/kg/day during the dry season. Their weight gain was assessed monthly. The pasture structure was assessed through destructive sampling, and the bromatological composition of esophageal extrusa samples was also assessed. Analysis of variance was used to assess performance, and regression analysis was used to evaluate the sward canopy characteristics in relation to the months of the year. A cluster procedure was used to determine the similarity between the months of the year under assessment. Two different groups were formed for pasture evaluation: one group including the months of March to July and another group including the months of August and September. The first group exhibited a better canopy structure than the second group. This fact was corroborated by the animal performance, which was lower during the months of the second group. Low-intake protein supplementation was effective in increasing the performance of the grazing heifers. Pasture structure is critical for animal performance in a grazing environment, regardless of the type of supplementation.

Parâmetros ruminais e desaparecimento da FDN da forragem em bovinos suplementados em pastagem na estação das águas

O objetivo do presente trabalho foi determinar o efeito de suplementos concentrados com diferentes degradabilidades da proteína (alta-75%, média-55% e baixa-35%) e o efeito da quantidade dos mesmos (0,5, 1,0 e 1,5 kg de MS/dia) sobre os parâmetros ruminais (pH e N-NH3) e o desaparecimento da FDN da forragem em bovinos pastejando Brachiaria brizantha cv. Marandu no período das águas. Foram utilizados dez bovinos canulados no rúmen com peso médio de 463 kg num esquema fatorial 3 x 3 com três repetições (blocos). A técnica do saco de náilon e a simulação do pastejo foram usadas para alcançar a cinética de degradação da FDN da forragem. Foram determinadas as concentrações N-NH3 e o pH ruminais durante dois dias, em vários horários. Não houve efeito dos suplementos, tampouco da quantidade destes sobre o desaparecimento da FDN da forragem, mas houve para os diferentes tempos de incubação, alcançando o potencial máximo de degradação (67,58%) às 96 horas de incubação. O pH ruminal variou de 5,7 a 7,4 com média de 6,48, não havendo efeito de tratamento e nem interação tratamento x tempo. Já para os horários de determinação houve diferenças significativas. Para o N-NH3 ruminal houve diferença significativa entre os tratamentos, sendo as maiores concentrações observadas para aqueles que apresentavam maior degradabilidade da proteína. Os primeiros horários após a suplementação apresentavam um maior pico de N-NH3 e os picos do período da manhã foram maiores que os da tarde. As diferentes concentrações de N-NH3 ruminal não alteraram a degradação da fibra.