10,220 research outputs found

    I Raised My Boy To Be A Soldier

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    https://digitalcommons.library.umaine.edu/mmb-vp/5290/thumbnail.jp

    Testing wheat for internal infesting insects with an electrically conductive roller mill: Presentation

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    Although grain is always inspected for adult insects and insect damaged kernels upon shipping and receiving, immature insects living inside the kernels of grain cannot be readily detected. A laboratory roller mill was modified to measure and analyze the electrical conductance of wheat as it was crushed. The electrical conductance of normal wheat kernels is low and fairly constant. In contrast, the electrical conductance of infested wheat kernels produces a sudden change in the electrical signal. The peak height of the electrical spike depends on the size of the larvae and the resulting contact of the crushed larvae between the rolls. This instrument was designed to test wheat with moisture content of 13.5% or less. The laboratory mill can test a kilogram of wheat in less than 2 min. Hard red winter and soft red winter wheat samples were used in experiments. Known numbers of infested kernels were added to the wheat samples. The infested kernels contained larvae of rice weevils and lesser grain borers sorted into large, medium, and small size groups. The instrument detected ~8 of 10 infested kernels per 100 g of wheat with large-larvae (fourth instar or pupae). It detected ~7 of 10 infested kernels with medium-larvae (second or third instar) and ~5 of 10 infested kernels infested with the small-larvae (first or second instar). Under reasonable grain moisture and careful sample handling, there were no non-infested kernels classified as insect infested. The mill can lead to rapid and automated detection of infested wheat.Although grain is always inspected for adult insects and insect damaged kernels upon shipping and receiving, immature insects living inside the kernels of grain cannot be readily detected. A laboratory roller mill was modified to measure and analyze the electrical conductance of wheat as it was crushed. The electrical conductance of normal wheat kernels is low and fairly constant. In contrast, the electrical conductance of infested wheat kernels produces a sudden change in the electrical signal. The peak height of the electrical spike depends on the size of the larvae and the resulting contact of the crushed larvae between the rolls. This instrument was designed to test wheat with moisture content of 13.5% or less. The laboratory mill can test a kilogram of wheat in less than 2 min. Hard red winter and soft red winter wheat samples were used in experiments. Known numbers of infested kernels were added to the wheat samples. The infested kernels contained larvae of rice weevils and lesser grain borers sorted into large, medium, and small size groups. The instrument detected ~8 of 10 infested kernels per 100 g of wheat with large-larvae (fourth instar or pupae). It detected ~7 of 10 infested kernels with medium-larvae (second or third instar) and ~5 of 10 infested kernels infested with the small-larvae (first or second instar). Under reasonable grain moisture and careful sample handling, there were no non-infested kernels classified as insect infested. The mill can lead to rapid and automated detection of infested wheat

    State-space based mass event-history model I: many decision-making agents with one target

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    A dynamic decision-making system that includes a mass of indistinguishable agents could manifest impressive heterogeneity. This kind of nonhomogeneity is postulated to result from macroscopic behavioral tactics employed by almost all involved agents. A State-Space Based (SSB) mass event-history model is developed here to explore the potential existence of such macroscopic behaviors. By imposing an unobserved internal state-space variable into the system, each individual's event-history is made into a composition of a common state duration and an individual specific time to action. With the common state modeling of the macroscopic behavior, parametric statistical inferences are derived under the current-status data structure and conditional independence assumptions. Identifiability and computation related problems are also addressed. From the dynamic perspectives of system-wise heterogeneity, this SSB mass event-history model is shown to be very distinct from a random effect model via the Principle Component Analysis (PCA) in a numerical experiment. Real data showing the mass invasion by two species of parasitic nematode into two species of host larvae are also analyzed. The analysis results not only are found coherent in the context of the biology of the nematode as a parasite, but also include new quantitative interpretations.Comment: Published in at http://dx.doi.org/10.1214/08-AOAS189 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org

    Effects of Rearing Density, Age, Sex, and Food Deprivation on Flight Initiation of the Red Flour Beetle (Coleoptera: Tenebrionidae)

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    Effects of rearing density, adult density and sex ratio in the flight chamber, adult age, sex, presence or absence of food, and duration of food deprivation on rate of and time to flight initiation of the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), were studied in the laboratory. Rates of flight initiation were slightly lower at lower rearing densities, but they did not differ with age or sex of adults, presence or absence of food in the flight chamber, or duration of food deprivation. Focal adults were less likely to fly when individuals of the opposite sex were present in flight chambers. Presence of the same sex or mixed sexes and numbers of individuals in flight chambers did not affect tendency to fly of focal individuals. Mean time to flight of older beetles (7-20 d old) was less than that of younger beetles (1-4 d old). No young beetles flew during the first 24 h of flight tests. Mean time to flight did not differ with rearing density, sex, presence or absence of food, or duration of food deprivation. Our results indicate that this species is highly dispersive during the adult stage and that flight does not seem to be associated with just prereproductive or postreproductive dispersal phases, high rearing density, or short to medium periods of food deprivation. Therefore, T. castaneum level of flight activity does not seem to be associated with factors that have been shown in the literature to increase dispersal by walking for this species and to increase flight initiation in other stored-product species

    Effect of Abiotic Factors on Initiation of Red Flour Beetle (Coleoptera: Tenebrionidae) Flight

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    Traps baited with pheromones are used to monitor the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), populations in flour mills to aid in making pest management decisions, but the factors that influence T. castaneum movement are not fully understood. We investigated the impact of photoperiod, light intensity, temperature, and relative humidity on flight initiation. The percentage of adults initiating flight reached a maximum at 30-35°C, and then fell to zero at 22.5 and 45°C. Only 2% of beetles flew in complete darkness, and the number of beetles initiating flight increased to 41% under 18 h of light and then decreased slightly to 37% under 24 h of light. Rates of flight initiation did not vary with light intensities from 1,784 to 4,356 lux or relative humidities from 25 to 85%. Thus, temperature and photoperiod are the main abiotic factors tested that impact flight initiation in T. castaneum, which have broad ranges of temperatures and photoperiods over which they can fly. The current results should be useful in helping to interpret trap catches based on abiotic conditions during the trapping period, and the results should be useful in helping to understand T. castaneum movement outside grain storages and processing facilities and their potential to infest structures

    Effects of Rearing Density, Age, Sex, and Food Deprivation on Flight Initiation of the Red Flour Beetle (Coleoptera: Tenebrionidae)

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    Effects of rearing density, adult density and sex ratio in the flight chamber, adult age, sex, presence or absence of food, and duration of food deprivation on rate of and time to flight initiation of the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), were studied in the laboratory. Rates of flight initiation were slightly lower at lower rearing densities, but they did not differ with age or sex of adults, presence or absence of food in the flight chamber, or duration of food deprivation. Focal adults were less likely to fly when individuals of the opposite sex were present in flight chambers. Presence of the same sex or mixed sexes and numbers of individuals in flight chambers did not affect tendency to fly of focal individuals. Mean time to flight of older beetles (7-20 d old) was less than that of younger beetles (1-4 d old). No young beetles flew during the first 24 h of flight tests. Mean time to flight did not differ with rearing density, sex, presence or absence of food, or duration of food deprivation. Our results indicate that this species is highly dispersive during the adult stage and that flight does not seem to be associated with just prereproductive or postreproductive dispersal phases, high rearing density, or short to medium periods of food deprivation. Therefore, T. castaneum level of flight activity does not seem to be associated with factors that have been shown in the literature to increase dispersal by walking for this species and to increase flight initiation in other stored-product species

    Tribolium castaneum (Coleoptera: Tenebrionidae) associated with rice mills: fumigation efficacy and population rebound

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    The red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), is the most important stored-product insect pest infesting rice (Oryza sativa L.) mills in the United States. Due to the phasing out of methyl bromide in accordance with the 1987 Montreal Protocol, the efficacy of alternative fumigants in controlling flour beetles in mill structures must be evaluated. Long-term trapping data sets (2-6 yr) of T. castaneum in and around seven rice mills were analyzed to assess the efficacy of sulfuryl fluoride fumigation (n = 25). Fumigation efficacy was evaluated as the percentage reduction in mean trap captures of adults and proportion of traps capturing at least one adult beetle. Beetle trap captures fluctuated seasonally, with increased captures during the warmer months, June-September, that dropped off during the cooler months, October-March. Fumigations resulted in a 66 ± 6% (mean ± SE) reduction in mean trap captures within mills and a 52 ± 6% reduction in the proportion of traps capturing at least one adult beetle. Lengths of time for captures to reach prefumigation levels, or rebound rates, were variable, and adult capture levels inside were most influenced by seasonal temperature changes. Temperatures inside mills followed those outside the mill closely, and a significant positive relationship between outside temperatures and trap captures was observed. Inside and outside trap captures exhibited a significant, positive relationship, but fumigations consistently led to reductions in beetle captures outside of mills, highlighting the interconnectedness of populations located inside and outside mill structures

    Geostationary earth climate sensor: Scientific utility and feasibility, phase A

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    The possibility of accurate broad band radiation budget measurements from a GEO platform will provide a unique opportunity for viewing radiation processes in the atmosphere-ocean system. The CSU/TRW team has prepared a Phase 1 instrument design study demonstrating that measurements of radiation budget are practical from geosynchronous orbit with proven technology. This instrument concept is the Geostationary Earth Climate Sensor (GECS). A range of resolutions down to 20 km at the top of the atmosphere are possible, depending upon the scientific goals of the experiment. These tradeoffs of resolution and measurement repeat cycles are examined for scientific utility. The design of a flexible instrument is shown to be possible to meet the two goals: long-term, systematic monitoring of the diurnal cycles of radiation budget; and high time and space resolution studies of regional radiation features

    Basing rate adjustments for motor carriers on statistical evidence

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    Pricing services of motor carriers is a dynamic process, with continuous pressure from customers to offer competitive rates and discounts. This can lead to a profusion of special arrangements with rates that poorly reflect the services rendered. This article shows how standard database systems and statistical models can be used to extract useful information from bills of lading to assist in the pricing of freight services. Summaries of business performance are produced according to terminal facility, shipping origin, shipping destination, individual shipping lane and individual customer. User-friendly statistical models are constructed to produce benchmarks for rates and revenues considering the services rendered. Differences between actual and benchmark levels of performance help to identify situations that may call for managerial reinforcement or corrective intervention. With illustrations from a major motor carrier, the authors discuss how even small motor carriers can develop such models and use them for planning their rate adjustments and managing customer relationships

    Distribution of three psocid species (Psocoptera: Liposcelididae) in different moisture gradients in wheat

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    Psocids can cause considerable economic losses to stored products by direct feeding, and they have become global pests during the last two decades. We studied the distribution of Liposcelis bostrychophila Badonnel (Psocoptera: Liposcelididae), Liposcelis entomophila (Enderlein), and Liposcelis brunnea Motschulsky in different moisture gradients (11-12-13%, 11-13-15%, and 13-14-15%) and a control (13-13-13%) in wheat using a circular metal arena, which has a removable metal divider that partitioned it into three rings (outer, middle and inner). Lipsocelis bostrychophila and L. entomophila preferred grain with the highest moisture content in the different gradients evaluated. In general, populations of Liposcelis brunnea equally preferred grain with moisture contents greater than or equal to 13%. These results showed the moisture contents preferred for three of the main psocid pests of stored grains, and this could help in making better pest management decisions
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