Although chronic pain (CP) is classified as inflammatory or non-inflammatory, the involvement of fatty acid intake in this process has not yet been examined in detail. Therefore, the present study investigated whether the relationship between CP and fatty acid intake differs between high and low C-reactive protein (CRP) levels in middle-aged and elderly individuals in the Shika study. One-thousand and seven males and 1216 females with mean ages of 68⋅78 and 69⋅65 years, respectively, participated in the present study. CRP was quantified by blood sampling from participants who responded to a CP questionnaire. The brief-type self-administered diet history questionnaire (BDHQ) was used to assess fatty acid intake. Interactions were observed between CP and CRP on monounsaturated fatty acids (MUFA) and eicosadienoic acid in a two-way analysis of covariance adjusted for sex, age, lack of exercise, lack of sleep, current smoking and drinking status, and BMI. MUFA (OR 1⋅359) and eicosadienoic acid (OR 1⋅072) were identified as significant independent variables for CP in a multiple logistic regression analysis, but only in the low CRP group. Only a high intake of MUFA and eicosadienoic acid was associated with chronic neck/shoulder/upper limb pain without elevated CRP. In psychogenic and neuropathic pain without elevated CRP, an increased intake of MUFA and eicosadienoic acid, a family member of n-6 fatty acids, appears to affect CP. Further longitudinal studies are needed to elucidate this relationship.

We assume that human carrying capacity is determined by food availability. We propose three classes of human population dynamical models of logistic type, where the carrying capacity is a function of the food production index. We also employ an integration-based parameter estimation technique to derive explicit formulas for the model parameters. Using actual population and food production index data, numerical simulations of our models suggest that an increase in food availability implies an increase in carrying capacity, but the carrying capacity is “self-limiting” and does not increase indefinitely.

Field research was conducted in Tennessee at two locations over 3 yr under no-tillage conditions to examine the interaction of broadleaf signalgrass and corn yield. Broadleaf signalgrass was killed at various time intervals during the growing season by applying postemergent glyphosate. Corn injury was avoided by the use of a glyphosate-tolerant variety. Yield reductions because of broadleaf signalgrass interference occurred with weed densities > 150 plants m−2 and when the corn and weeds emerged simultaneously. Corn had the ability to withstand broadleaf signalgrass presence up to 28 d after planting with no yield loss at all locations.

Where the nonnative annual grass downy brome proliferates, it has changed ecosystem processes, such as nutrient, energy, and water cycles; successional pathways; and fire regimes. The objective of this study was to develop a model that predicts the presence of downy brome in Central Oregon and to test whether high presence correlates with greater cover. Understory data from the U.S. Department of Agriculture (USDA) Forest Service's Current Vegetation Survey (CVS) database for the Deschutes National Forest, the Ochoco National Forest, and the Crooked River National Grassland were compiled, and the presence of downy brome was determined for 1,092 systematically located plots. Logistic regression techniques were used to develop models for predicting downy brome populations. For the landscape including the eastside of the Cascade Mountains to the northwestern edge of the Great Basin, the following were selected as the best predictors of downy brome: low average March precipitation, warm minimum May temperature, few total trees per acre, many western junipers per acre, and a short distance to nearest road. The concordance index = 0.92. Using the equation from logistic regression, a probability for downy brome infestation was calculated for each CVS plot. The plots were assigned to a plant association group (PAG), and the average probability was calculated for the PAGs in which the CVS plots were located. This method could be duplicated in other areas where vegetation inventories take place.

Broad- host-range pathogens are appealing as candidates for commercial development as bioherbicides because of the wider market potential of a product that is effective against a range of weeds. But when these pathogens are able to spread in space (or time), a risk analysis is necessary. Here we test the hypothesis that a safety zone around a bioherbicide application site is adequate so long as it is wide enough to ensure that dispersing inoculum has diluted sufficiently that the density of inoculum occurring naturally in a susceptible crop is no more than doubled by the influx of bioherbicide spores. To this end the plant disease–pathogen inoculum density relationship using data from nine published experiments was modeled using the logistic equation. This revealed that a doubling of the natural spore density of a plant pathogen in the range of 103.4 to 106.7 spores/ml may generally be expected to result in unacceptable increases in disease in a susceptible crop. A doubling outside this range (< 103.4 or > 106.7) is less likely to do so. Therefore when the natural density of inoculum in a crop's environment occurs outside this range, an “acceptable” safety zone for the pathogen's use as a bioherbicide can in most cases be defined by the 1 : 1 ratio of added : natural inoculum. However, if a more “risk averse” safety zone is desired, it can be defined using a 1 : 10 ratio of added : natural inoculum.

Field trials were conducted to determine potato response to parts per trillion (ppt) per weight concentrations of sulfometuron in soil. The herbicide was applied to achieve targeted, 0-d soil concentrations of 0, 7.5, 15, 30, 60, 120, 240, 480, and 960 ppt. Russet Burbank potatoes were planted immediately after application using standard agronomic practices. Based on midseason visual evaluations, root and tuber injury occurred with 0-d concentrations of only 7.5 ppt. Concentrations at or above 120 ppt caused a significant increase in number of tubers with deformities compared with the control. By the end of the growing season, 0-d concentrations between 120 and 240 ppt resulted in higher percentages of tubers with deformities, such as cracks, knobs, or folds. Using logistic models fit to U.S. No. 1 tuber yield and net return data, doses of 74, 156, and 324 ppt are predicted to result in 5, 10, and 20% U.S. No. 1 yield reductions, respectively. The model predicted a 20% net return loss, approximately $160/ha, occurring at 262 ppt, which is near the 240 ppt concentration determined by standard ANOVAs and means comparisons with single degree of freedom contrasts causing significant tuber quality and yield reductions in our study. Growers using the 240 ppt concentration as an indicator of a no-effect level would encounter actual losses too great to withstand. This modeling approach provides an initial attempt at giving growers the tools necessary for assessing potential losses.

Few studies have examined the combined effect of herbicide-induced stress and arthropod herbivory to reduce weed fitness. The purpose of this study was to quantify the effect of arthropod herbivory on the herbicide dose–response of a perennial weed. Fluroxypyr dose–response bioassays using volunteer potato were conducted in the presence and absence of Colorado potato beetle (CPB) herbivory. Logistic model parameter estimates for leaf area, shoot biomass, tuber number, and tuber biomass were often lower with herbivory, compared with no herbivory. Greater variance of parameter estimates within herbivory plots was attributed largely to differential feeding because CPB density was not manipulated in the field. Results from short-season field studies (1,000 growing degree days [GDD] after postemergence [POST] herbicide application) indicated that herbivory had the most effect on potato during a period that coincided with high CPB density and optimal temperatures for CPB development. Season-long bioassays (> 3,100 GDD after POST) revealed that addition of herbivory reduced herbicide use 65 to > 85%, compared with the dose needed to achieve the same reduction in tuber production in the absence of herbivory. Integrated weed management systems targeting volunteer potato are more effective when fluroxypyr applications are made before periods of high herbivory. Moreover, this article describes an experimental approach contributing to optimization of combined effects of arthropod herbivory and reduced herbicide doses.

A ratio-based logistic model developed to assess elephant harvest rates, based on a study at Nagarhole Tiger Reserve in India, was recommended as a management tool to control human–elephant conflict through culling. Considering this reserve among others violates an assumption of the logistic model: isolation. Nevertheless, assuming this violation was irrelevant, we re-evaluated the model, with minor modifications, for the neighbouring Mudumalai Tiger Reserve, where we used data from 13 elephant Elephas maximus population surveys to derive bootstrapped sets of population ratios, and mortality records. We generated arrays of harvest regimes and examined which ratio outputs were closest to the bootstrapped ratios. Our results indicated that (1) model outputs corresponded best with the Mudumalai population structure when harvest regimes were extreme and unlikely, (2) there were significant differences in population structure and harvest regimes between Nagarhole and Mudumalai, and (3) only 49% of adult male deaths predicted by model outputs were recorded in official governmental records. The model provides significantly different results among reserves, which invalidates it as a tool to predict change across the entire elephant population. Variability in survey data and inaccuracies in transition probabilities are sufficiently large to warrant caution when using them as a basis for deterministic modelling. Official mortality databases provide a weak means of validation because poaching incidents are poorly recorded. We conclude that the model should be based on validated transition probabilities and encompass the entire regional population.

This paper studies the genetic importance of growth curve parameters and their relevance as selection criteria in breeding programmes of Segureño sheep. Logistic and Verhulst growth functions were chosen for their best fit to BW/age in this breed; the first showed the best general fit and the second the best individual fit. Live weights of 41 330 individuals from the historical archives of the National Association of Segureña Sheep Breeders were used in the analysis. The progeny of 1464 rams and 27 048 ewes were used to study the genetic and phenotypic parameters of growth curve parameters and derived traits. Reproductive management in the population consists in controlled natural mating inside every herd, with a minimum of 15% of the females fertilized by artificial insemination with fresh semen; with the purpose being the herd genetic connections, all herd genealogies are screened with DNA markers. Estimates of growth curve parameters from birth to 80 days were obtained for each individual and each function by the non-linear regression procedure using IBM SPSS statistics (version 21) with the Levenberg–Marquart estimation method. (Co)variance components and genetic parameters were estimated by using the REML/Animal model methodology. The heritability of mature weight was estimated as 0.41±0.042 and 0.38±0.021 with the logistic and Verhulst models, respectively, and the heritability of other parameters ranged from 0.41 to 0.62 and 0.37 to 0.61, with the models, respectively. A negative genetic correlation between mature weight and rate of maturing was found.

We used a factorial approach to distinguish maintenance from growth requirements for protein, lysine and methionine in the black tiger shrimp, Penaeus monodon. Juvenile P. monodon (initial weight 2·4 g) were fed during 6 weeks one of ten semi-purified diets based on casein and purified amino acids (AA) as N source. The diets contained four levels of crude protein (CP, from 5 to 54 % DM diet) with two levels (% CP) of lysine or methionine (normal or 30 % deficient). Requirements were determined using linear and non-linear regression models. We could thus obtain the first ever data on maintenance (N equilibrium) requirements for CP and AA in P. monodon. CP requirements for maintenance (4·5 g/kg body weight (BW) per d) represented approximately 19 % of the CP requirement for maximal N gain (23·9 g/kg BW per d). The marginal efficiency of utilisation reached a maximum of 38 % for N, 0·77 for lysine and 1·62 for methionine using N gain as response. Lysine requirements were 0·20 g/kg BW per d for N maintenance and 1·40 g/kg BW per d for maximal N gain. Methionine requirements were 0·11 g/kg BW per d for N maintenance and 0·70 g/kg BW per d for maximal N gain. The lysine (5·8 %) and methionine (2·9 %) requirements for maximal N gain, expressed as percentage of protein requirement, agree with literature data using a dose–response technique with smaller P. monodon. The observed interaction between dietary CP and methionine for N gain demonstrates that requirements for indispensable AA (expressed as % CP) cannot be evaluated separately from CP requirements.

Over 61% of farmers who sell agricultural products through farmers' markets are satisfied with the returns they generate. Producers who are 50 years of age or older and those who retail at least 70% of the dollar value of the products are more likely to be highly satisfied with their profit margin from farmers' markets. A strong positive relationship is documented between profit margin satisfaction and growers who offer organic produce for sale. Furthermore, the results suggest that producers with farmers' market businesses in the growing stage are more likely to be highly satisfied with profit margins.

The growth and the food requirements of the European barn owl (Tyto alba) were studied in three groups of captive chicks. One group of chicks, raised in ad libitum food conditions by their parents, was used to measure body mass and linear growth of a number of structural body components at their characteristic growth rate. A second group of chicks, hand-raised with food ad libitum until fledging, was used to measure food requirement at the characteristic growth rate. A third group, hand-raised with restricted feeding, was used to specify the plasticity of growth and food requirements still compatible with a normal development at fledging. Chicks of both sexes of the first two groups experienced an overshoot in body mass (maximum of 391 g) when approximately 40 days old, followed by a decrease (to a mass of 314 g) until fledging at 60 days old, giving a mass distribution with age in the form of a bell-shaped curve. The daily food intake also showed a bell-shaped curve with a peak value of 80 ± 10 g of fresh mice/day when the body mass was maximum. The decrease of food intake preceding fledging was spontaneous. The average daily food intake was 67 ± 17 g/day between the ages of 20 and 60 days. In the restricted feeding group, however, the same timing for linear growth and fledging was achieved with a 17% reduction of daily food intake. For the same fledging body mass as the ad libitum fed group, there was a flattening of the body mass curve. The significance of the overshoot in body mass and food intake is discussed in terms of the chick's and brood's advantages and in terms of parental investment in this species with hatching asynchrony.

Buprofezin treatment of brown planthopper, Nilaparvata lugens Stal. at sub-lethal doses resulted in the survival of individuals with varying reproductive potentials. From this reproductive potential of different stages, population build up of second generation was calculated. Logistic function was found to fit more closely the data on population growth at different concentrations. It could thus serve as a mathematical model for predicting the second generation population build up in a buprofezin treated population.

The exact time-dependent solution as well as the stationary solution of the logistic model for population growth with varying carrying capacity is worked out in both the Stratonovich and Ito calculi by solving the forward Kolmogorov equation.