Search

To determine the effect of massed instruction (MI) versus spaced instruction (SI) of veterinary surgical skills on students' cognitive load and skill retention.Prospective randomized cohort study STUDY POPULATION: First-year veterinary students from Louisiana State University (LSU; n = 47) and Lincoln Memorial University (LMU; n = 101).Students were randomized to MI (two skills in a single session of twice the duration) or SI (one skill per session on two consecutive days). Instructors, instructional ratio, and total educational time was equivalent. Following instruction, students completed a cognitive load questionnaire and underwent a structured assessment immediately after (LMU only), 1 day after, and 3-4 weeks after learning the second skill. Students completed two supervised practice sessions one and 2 weeks after the initial laboratory session(s).Overall cognitive load did not differ between groups (p .05), although LMUs MI group reported higher physical and time demands, effort, and frustration. At initial assessment, SI students scored higher than MI students for the first skill at both LSU (mean checklist score = 27.7 vs. mean = 24; p = .004) and LMU (mean global rating score = 4.76 vs. mean = 4.55; p = .029). Differences between groups were no longer evident by 3-4 weeks after instruction.SI may lead to improved immediate performance; however, supervised practice was sufficient to overcome the initial disparity.SI may be beneficial for initial skill performance. However, SI and MI students had similar performance after 3 weeks, suggesting the more convenient curricular design of MI may be sufficient as long as practice sessions are incorporated.

Stream water chemistry is traditionally measured as variation over time at fixed sites, with sparse sites providing a crude understanding of spatial heterogeneity. An alternative Lagrangian reference frame measures changes with respect to both space and time as water travels through a network. Here, we collected sensor‐based measurements of water chemistry at high spatial resolution along nearly 500 km of the Upper Colorado River. Our objective was to understand sources of spatiotemporal heterogeneity across different solutes and determine whether longitudinal change manifests as smooth gradients as suggested by the River Continuum Concept (RCC) or as abrupt changes as suggested by the Serial Discontinuity Concept (SDC). Our results demonstrate that Lagrangian sampling integrates spatiotemporal variation, and profiles reflect processes that vary in both space and time and over different scales. Over each day of sampling, water temperature (T) and dissolved oxygen (DO) varied strongly in response to diel solar cycles, with most of the variation driven by sampling time rather than sampling location. Equilibration of T and DO with the atmosphere limited small scale spatial heterogeneity, with variation at the entire profile scale driven by regional climate gradients. As such, T and DO profiles more closely approximated the smooth gradients of the RCC (though including temporal sampling artefacts). Conversely, variation in specific conductance and nitrate (NO₃‐N) was largely driven by spatial patterns of lateral inflows such as tributaries and groundwater. This resulted in discrete shifts in the profiles at or downstream of discontinuities, appearing as the profiles expected with the SDC. The concatenation of spatiotemporal variation that produces observed Lagrangian profiles presents interpretive challenges but also augments our understanding of where, how, and critically why water chemistry changes in time and space as it moves through river networks.

Wetland ecosystems play a significant role in the global carbon cycle, and yet are increasingly threatened by human development and climate change. The continued loss of intact freshwater wetlands heightens the need for effective wetland creation and restoration. However, wetland structure and function are controlled by interacting abiotic and biotic factors, complicating efforts to replace ecosystem services associated with natural wetlands and making ecologically-driven management imperative. Increasing waterfowl populations pose a threat to the development and persistence of created wetlands, largely through intensive grazing that can shift vegetation community structure or limit desired plant establishment. This study capitalized on a long-term herbivore exclusion experiment to evaluate how herbivore management impacts carbon cycling and storage in a created wetland in Western New York, USA. Vegetation, above- and belowground biomass, soil carbon, carbon gas fluxes and decomposition rates were evaluated in control plots with free access by large grazers and in plots where grazers had been excluded for four years. Waterfowl were the dominant herbivore at the site. Grazing reduced peak growing season aboveground biomass by over 55%, and during the summer, gross primary productivity doubled in grazer exclusion plots. The shift in plant productivity led to a 34% increase in soil carbon after exclusion of grazers for five growing seasons, but no change in belowground biomass. Our results suggest that grazers may inhibit the development of soil carbon pools during the first decade following wetland creation, reducing the carbon sequestration potential and precluding functional equivalence with natural wetlands.

Gross primary production and ecosystem respiration together define ecosystem metabolism and help indicate the importance of internal and external carbon sources. Spatial variability of these processes is poorly characterized in rivers. We measured metabolism in the Kansas River: (1) at 10 locations over 100 s of km in tributaries within the watershed and (2) over 20 km with detailed sampling in the main stem. Whole-river metabolism at the larger scale was decoupled from light, algal growth, and nutrient limitation, and was positively related to nutrients. Smaller-scale main stem sampling revealed almost as much variance over a few kilometers as the larger scale sampling. Local processes seemed to dominate dissolved oxygen dynamics, since diurnal dissolved oxygen patterns were better correlated with absolute time than data corrected for travel times. A single-station method compared against two-station metabolism methods indicated that local hotspots of metabolism occur at scales less than 1 km and that single-station estimates average out this variance. The main stem data provide support to the idea that functional processing zones control characteristics used to estimate system metabolism, but the nutrient effect at the whole watershed level indicates that transport from upstream can also be important.

Nociceptin and its receptor are widely distributed throughout the brain in regions associated with reward behavior, yet how and when they act is unknown. Here we dissected the role of a nociceptin peptide circuit in reward seeking. We generated a prepronociceptin (Pnoc)-Cre mouse line that revealed a unique subpopulation of paranigral ventral tegmental area (pnVTA) neurons enriched in prepronociceptin. Fiber photometry recordings during progressive ratio operant behavior revealed pnVTA(Pnoc) neurons become most active when mice stop seeking natural rewards. Selective pnVTA(Pnoc) neuron ablation, inhibition and conditional VTA nociceptin receptor (NOPR) deletion increased operant responding, revealing that the pnVTA(Pnoc) nucleus and VTA NOPR signaling are necessary for regulating reward motivation. Additionally, optogenetic and chemogenetic activation of this pnVTA(Pnoc) nucleus caused avoidance and decreased motivation for rewards. These findings provide insight into neuromodulatory circuits that regulate motivated behaviors through identification of a previously unknown neuropeptide-containing pnVTA nucleus that limits motivation for rewards.

Optical manipulations of genetically defined cell types have generated significant insights into the dynamics of neural circuits. While optogenetic activation has been relatively straightforward, rapid and reversible synaptic inhibition has proven more elusive. Here, we leveraged the natural ability of inhibitory presynaptic GPCRs to suppress synaptic transmission and characterize parapinopsin (PPO) as a GPCR-based opsin for terminal inhibition. PPO is a photoswitchable opsin that couples to Gi/o signaling cascades and is rapidly activated by pulsed blue light, switched off with amber light, and effective for repeated, prolonged, and reversible inhibition. PPO rapidly and reversibly inhibits glutamate, GABA, and dopamine release at presynaptic terminals. Furthermore, PPO alters reward behaviors in a time-locked and reversible manner in vivo. These results demonstrate that PPO fills a significant gap in the neuroscience toolkit for rapid and reversible synaptic inhibition and has broad utility for spatiotemporal control of inhibitory GPCR signaling cascades.

Effective and safe doses of opiate painkillers, like morphine, can be limited by respiratory depression. Schmid et al. (2017) now present a quantitative method to design ligands and correlate GPCR signaling bias to the dose separation between therapeutic and adverse effects in animals.

Comprehensive studies that consolidate selective ligands, quantitative comparisons of G protein versus arrestin-2/3 coupling, together with structure-activity relationship models for G protein–coupled receptor (GPCR) systems are less commonly employed. Here we examine biased signaling at the nociceptin/orphanin FQ opioid receptor (NOPR), the most recently identified member of the opioid receptor family. Using real-time, live-cell assays, we identified the signaling profiles of several NOPR-selective ligands in upstream GPCR signaling (G protein and arrestin pathways) to determine their relative transduction coefficients and signaling bias. Complementing this analysis, we designed novel ligands on the basis of NOPR antagonist J-113,397 [(±)-1-[(3R*,4R*)-1-(cyclooctylmethyl)-3-(hydroxymethyl)-4-piperidinyl]-3-ethyl-1,3-dihydro-2H-benzimidazol-2-one] to explore structure-activity relationships. Our study shows that NOPR is capable of biased signaling, and further, the NOPR selective ligands MCOPPB [1-[1-(1-methylcyclooctyl)-4-piperidinyl]-2-(3R)-3-piperidinyl-1H-benzimidazole trihydrochloride] and NNC 63-0532 [8-(1-naphthalenylmethyl)-4-oxo-1-phenyl-1,3,8-triazaspiro[4.5]decane-3-acetic acid, methyl ester] are G protein–biased agonists. Additionally, minor structural modification of J-113,397 can dramatically shift signaling from antagonist to partial agonist activity. We explore these findings with in silico modeling of binding poses. This work is the first to demonstrate functional selectivity and identification of biased ligands at the nociceptin opioid receptor.

Sap-feeding and predaceous arthropod faunas of forage bunchgrasses in reseeded rangeland vegetation were examined. Four major species of sap feeders were found; the major predators were spiders. Grass monoculture had very high densities of sap feeders compared with grass biculture, shrub-grass, tree-grass, and native areas; this was reflective of the large contribution from the mirids Irbisia brachycera Uhler and Conostethus americanus (Knight). They were present during the leaf stages of crested wheatgrass when it had its lowest carbohydrate root reserves. Homoptera and predator densities were not significantly related to the pattern of vegetation. The lowest number of sap-feeder species occurred in the grass monoculture, and sap-feeder faunas in this plot were dissimilar to those of all other plots. One-season dispersal experiments did not support the hypothesis that grass density caused the differences between arthropod faunas in different vegetation, whereas big sagebrush, common in reseeded pastures, repelled I. brachycera during short-term dispersal. The data indicate that reseeding to monocultures may result in high densities of Miridae during the leaf stages compared with moderate densities of Homoptera during the flower and seed stages in bicultures. The implications for pest management are discussed.

The present study focused on the assessment of imitation performance in a large sample of 6- and 9-month-old infants from two different cultural contexts: German middle-class infants from urban areas and Nso infants from a rural area in northwestern Cameroon were tested by using age-adapted deferred imitation tasks that were varied regarding their cultural familiarity (two types of instruments each being highly familiar for one of the two cultural contexts). Within both cultural groups and without being influenced by the cultural familiarity of the instruments, infants performed more target actions in the test compared with the baseline phase, even though this difference did not yield significance in the group of 6-month-old Cameroonian Nso infants. Moreover, a higher mean number of imitated actions has been observed for 9-month-olds compared with 6-month-olds demonstrating an age-related improvement of infants’ learning ability. Furthermore, at 9 months of age, German infants showed a higher level of baseline activity compared with the infants in the Cameroonian sample, which is assumed to be based on differences regarding the degree of object experiences. Results provide evidence that early in infancy, imitation is a universal learning tool in different cultural environments.

This longitudinal study examined the influence of stimulus material on attention and expectation learning in the visual expectation paradigm. Female faces were used as attention-attracting stimuli, and non-meaningful visual stimuli of comparable complexity (Greebles) were used as low attention-attracting stimuli. Expectation learning performance was operationalized using the average reaction time and number of anticipations. For the measurement of attention, the percentage of trials with on-task attention behavior was calculated. To analyze attention and differences in performance, a total of 108 German infants (3–6 months of age) were assessed. Significant differences were found between the two types of stimuli concerning the infants’ rate of attention and anticipations. The results indicate learning material to influence attentional processes and expectation learning.

Three-month-old Cameroonian Nso farmer and German middle-class infants were compared regarding learning and retention in a computerized mobile task. Infants achieving a preset learning criterion during reinforcement were tested for immediate and long-term retention measured in terms of an increased response rate after reinforcement and after a 24-h delay compared with baseline. It was hypothesized that infants from both cultural communities would acquire the contingency between own motion and mobile movement, as they similarly experience contingent responses in social interactions. Nso infants were assumed to show a higher learning rate related to their advanced gross motor development, whereas German infants were expected to show a higher baseline because of culture-typical motor handling promoting a high level of activity (i.e. lying supine). Results showed immediate and long-term retention in infants from both cultural contexts, as well as a higher baseline for German infants. Although the learning rate was higher for Cameroonian infants, logistic regression revealed that learning was not related to gross motor development but depended on the level of baseline response. Thus, contingency learning was shown in different cultural environments, and the level of baseline activity coined by culture-specific motor handling turned out to influence learning within the mobile task. Copyright (c) 2012 John Wiley & Sons, Ltd.

This longitudinal study assessed 133 Caucasian German infants at 3 and 6 months of age to investigate the influence of own-race and other-race faces as visual stimuli on association learning in the visual expectation paradigm (VExP). The study is related to the findings on the other-race-effect (ORE) which is said to emerge at 6 months of age. Caucasian faces were used as stimuli of a familiar ethnic category, whereas African faces were used as stimuli of an unfamiliar ethnic category. There was no significant difference between the two stimulus classes in infants' reaction time (RT) to stimulus shifts at 3 months. At 6 months of age, infants' RT decreased significantly in the Caucasian faces condition but not in the African faces condition. These results indicate that the processing of other-race versus own-race faces by the age of 6 months, which is also the relevant age for the onset of the ORE, has an important influence on the performance on the VExP. Copyright © 2011 John Wiley & Sons, Ltd.

The aim of the present study was to investigate whether temperament and cognitive abilities are related to recognition performance of Caucasian and African faces and of a nonfacial stimulus class, Greebles. Seventy Caucasian infants were tested at 3 months with a habituation/dishabituation paradigm and their temperament and cognitive abilities were measured. Analyses revealed that only infants with easy temperament recognized familiar Greebles from the habituation phase. A similar pattern was found for cognitive abilities showing that only infants with higher cognitive abilities recognized Greebles. Irrespectively of temperament and cognitive abilities, all infants recognized the faces. Thus, the data suggest that recognition of unfamiliar Greebles, but not of faces, is demanding for 3-month-old infants with difficult temperament or lower cognitive abilities.

Based on the Bayley Scales of Infant Development III, this study provides the results of a longitudinal study on the development of Cameroonian Nso farmer and German middle-class infants. Complete longitudinal data were available for 253 infants (69 from Cameroon and 184 from Germany) with Bayley assessments at 3, 6 and 9 months. The results show large differences between Cameroonian Nso and German infants with regard to gross motor and language development. The developmental sequence within each Bayley scale is more in line with the original Bayley sequence for German than for Cameroonian Nso infants as is indicated by Goodman scalogram analyses. Path analyses show some basic similarities between the developmental paths across ages for Cameroonian Nso and German infants, but more interconnections between the scales in the German sample. The results underline the need to adjust developmental scales to the cultural background of the infants to be tested.

Zusammenfassung. Schon gleich nach der Geburt bevorzugen es Säuglinge, Gesichter gegenüber anderen visuellen Objekten anzuschauen und lernen dann im Laufe des ersten Lebensjahres, immer mehr Gesichter zu unterscheiden und wiederzuerkennen. Es wird derzeit noch diskutiert, welche Faktoren für diese zunehmende Unterscheidungsleistung von Gesichtern verantwortlich sind. Ziel des vorliegenden Beitrags ist es darzulegen, welche Rolle die Faktoren – emotionaler Ausdruck von Gesichtern, Temperament und Kognition der Säuglinge sowie die Kultur – für eine solche Unterscheidungsleistung von Gesichtern innerhalb des ersten Lebensjahres spielen.

ADDITIONAL INDEX WORDS. Ostrinia nubilalis, Zea mays, prediction maps, spatial mapping, integrated pest management SUMMARY. Infestation of sweet corn (Zea mays) at harvest by european corn borer (Ostrinia nubilalis) was examined in 16 hybrid/harvest date combinations from 1994 through 1996 in central Pennsylvania. Two general periods of sweet corn ear infestation levels were observed. Infestations, expressed as proportion of ears infested, were 0.11 (11%) or lower in 10 of 11 plots harvested from 21 July to 23 Aug., whereas they were noticeably higher (30%–88%) in September and early October. Infestations expressed as larvae per ear showed the same temporal pattern. A nonlinear (sigmoidal) relationship was found between degree-days from 1 Jan. and proportion of ears infested. The higher infestations were caused by the secondgeneration larvae of the bivoltine ecotype. Based on these relationships, a riskprediction system is proposed that anticipates, at planting, harvest infestation by using predicted harvest dates of sweet corn, european corn borer life stages, and infestation levels. Examples are presented for multiple plantings and hybrids for a specific site and a landscape (Pennsylvania). The risk prediction system we propose will allow growers to anticipate the risk of ear infestations at planting time, thus providing predictions that would help with management decisions.

Guanine nucleotide binding proteins, such as Ras proteins, play a pivotal role in maintaining the regular life cycle of cells. The involvement of Ras mutants in the progress of cancer has attracted many efforts to find detection methods for Ras activity. In this study we present a luminescent microwell plate assay for monitoring GTPase activity of Ras proteins. The luminescence intensity of the Tb-norfloxacin complex is influenced by nucleoside phosphates as well as by inorganic phosphates. Real-time kinetics of the GTPase activity of wild-type Ras and Ras mutants can be monitored online. The effect of a GTPase activating protein as well as of a downstream effector (Ras-binding domain of human Raf-1) on the GTPase activity of different Ras mutants is examined. In contrast to other methods, this assay does not require the use of radioactively labeled substrates or chromatographic separation steps. Moreover, the application of fluorescently labeled GTP substrates which often interfere with enzymatic activity can be avoided. This in vitro assay can serve as a model system for the screening of regulators affecting the GTPase activity of Ras proteins.

The determination of enzyme activities and the screening of enzyme regulators is a major task in clinical chemistry and the development of new drugs. A broad variety of enzymatic reactions is associated with the consumption or formation of small molecules like H(2)O(2), ATP, pyrophosphate, or phosphate. Luminescent lanthanide complexes can be applied to monitor these enzymatic conversions and therefore can serve as probes for the determination of enzyme activities. The utility of this concept will be demonstrated by means of some selected examples including europium and terbium complexes. Accordingly, this new approach could be already implemented for the determination of glucose oxidase, catalase, and peroxidase activity. In particular, enzymes that catalyze phosphorylation or dephosphorylation reactions came to the fore of interest because of their high relevance as drug targets. These include (protein) kinases, adenylyl cyclases, phosphodiesterases, phosphatases, and ATPases. The development and design of fluorescent lanthanide complexes should lead to probes with optimized selectivity and response times that can be applied for high-throughput screening of enzyme inhibitors and for real-time monitoring of enzyme kinetics. In contrast to other assays for enzyme activity determination, this method does not require the use of radioactively labelled substrates or the accomplishment of rather complex and expensive immunoassays.

This study aims to analyze culture-specific development of maternal interactional behavior longitudinally. Rural Cameroonian Nso mothers (n = 72) and German middle-class mothers (n = 106) were observed in free-play interactions with their 3- and 6-month-old infants. Results reveal the expected shift from a social to a nonsocial focus only in the German middle-class mothers' play interactions but not the rural Nso mothers' play. Nso mothers continue their proximal interactional style with a focus on body contact and body stimulation, whereas German middle-class mothers prefer a distal style of interaction with increasing object-centeredness. These cultural differences are in line with broader cultural models and become more accentuated as the infants grow older.

Polymeric nanoparticles containing an oily core, named nanocapsules (NCs), have been widely studied in the life sciences field due to their therapeutic potentialities of drug targeting in the body accompanied also by its larger stability in the biological fluids compared to other colloidal carriers. Many studies have shown different applications of nanocapsules for therapeutic use concerning their properties [1] of loading poorly water-soluble drugs, protection drugs from inactivation in the gastro-intestinal tract [2], gastric mucosal toxicity protection [3,4], increased drug permeation through mucous epithelium [5,6] and prolongation of drugs in blood circulation for surface modified nanocapsules [7]. The characterization of the nanocapsules is frequently performed by mean size, surface charge of the particles (zeta potential), hydrophobicity, drug loading yield and release kinetic [8]. These features are of great importance for biodistribution profile and interactions with the cells of mononuclear phagocyte system of any injected particles by intravenous route [1]. However, few data on structural organization of the nanocapsules constituents are available in literature and several hypotheses only suggest the presence of an oil "capsular" structure surrounded by a polymeric envelope. Recently, atomic force microscope (AFM) has been used as a method for imaging the surfaces of colloidal systems, such as liposomes [9,10] and nanospheres [11], supplying high resolution information in nanoscaled dimension. In the present work, unloaded nanocapsules were deposited on mica in order to analyze by AFM the diameter, height, particles polydispersion, and topographic characteristics of nanocapsule surface.

Inflammation of the female reproductive tract increases susceptibility to HIV-1 and other viral infections and, thus, it becomes a serious liability for vaginal products. Excessive release of proinflammatory cytokines may alter the mucosal balance between tissue destruction and repair and be linked to enhanced penetration and replication of viral pathogens upon chemical insult. The present study evaluates four surface-active microbicide candidates, nonoxynol-9 (N-9), benzalkonium chloride (BZK), sodium dodecyl sulfate, and sodium monolaurate for their activity against human sperm and HIV, and their capacity to induce an inflammatory response on human vaginal epithelial cells and by the rabbit vaginal mucosa. Spermicidal and virucidal evaluations ranked N-9 as the most potent compound but were unable to predict the impact of the compounds on vaginal cell viability. Interleukin (IL)-1 release in vitro reflected their cytotoxicity profiles more accurately. Furthermore, IL-1 concentrations in vaginal washings correlated with cumulative mucosal irritation scores after single and multiple applications (P < 0.01), showing BZK as the most damaging agent for the vaginal mucosa. BZK induced rapid cell death, IL-1 release, and IL-6 secretion. The other compounds required either more prolonged or repeated contact with the vaginal epithelium to induce a significant inflammatory reaction. Increased IL-8 levels after multiple applications in vivo identified compounds with the highest cumulative mucosal toxicity (P < 0.01). In conclusion, IL-1, IL-6, and IL-8 in the vaginal secretions are sensitive indicators of compound-induced mucosal toxicity. The described evaluation system is a valuable tool in identifying novel vaginal contraceptive microbicides, selecting out candidates that may enhance, rather than decrease, HIV transmission.

Fumonisins were monitored in corn grain collected from Bt hybrids grown in 107 locations across the United States in 2000-2002. Bt corn hybrids contain the Cry1Ab protein from Bacillus thuringiensis that controls European corn borers and other stalk-boring pests. Fumonisin levels were frequently lower in grain from Bt hybrids grown in field trials under conditions of natural (FACT trials) or manual insect infestation (university trials). Over three years of FACT trials, there were 126/210 comparisons when fumonisin levels in grain from control hybrids were >2 ppm, exceeding U.S. FDA guidance levels of 2 ppm for human food. Grain from Bt hybrids was at or below 2 ppm of fumonisins for 58 of the 126 comparisons. The use of Bt hybrids can increase the percentage of corn grain that would be suitable for use in food and feed.

Short-term storage regimens containing elevated atmospheres of carbon dioxide (CO2) were evaluated for their ability to disinfest newly harvested 'McIntosh' apples of apple maggot, Rhagoletis pomonella (Walsh). Infested fruits containing newly laid eggs were either placed directly into the high-CO2 atmosphere at 10 degrees C to expose this life stage, or else held first for 7 d at room temperature, to allow development to the neonate larval stage. Treatment combinations consisted of three different CO2 levels (10.6, 14.9, and 19.0% CO2) and two periods of exposure (7 and 14 d). Apple maggot eggs subjected to the treatments always exhibited some survival, which was lower for the 14-d than the 7-d exposure periods. In contrast, newly hatched larvae were less able to survive the treatments. The 7-d exposure allowed low levels of survival of this life stage, but virtually none survived the 14-d exposure period. To determine the age at which eggs become more susceptible to high-CO2 atmospheres, infested fruits containing eggs three or 3d old were submitted to a 14-d exposure to 19.0% CO2. Survival of 3-d old eggs was similar to that of eggs exposed at an age of 1 d or less, but this dropped to near zero for 5-d old eggs, indicating an increase in susceptibility sometime during the 3-5-d age range. Fruits exposed to 19.0% CO2 for 14 d were significantly firmer than untreated fruits. No apparent browning, internal breakdown or other fruit defects were detected in any of the treatments.

How do animals respond to an unpredictably heterogeneous environment? Ants foraging in the leaf litter of tropical wet forests experience unpredictably fluctuating food resources. To study how an ant species responds to these changes, foragers were tracked to determine home ranges of 51 colonies of Aphaenogaster araneoides, in three sites in a Costa Rican tropical wet forest. Of these colonies 16 were excavated to measure colony size, colony growth, and reproductive investment. These demographic variables were compared with two measures of home range quality: leaf litter dry weight and mass of arthropods. Home range areas of colonies were highly correlated with colony size, and moderately correlated with resource abundance. Colony growth was independent of colony size, as is found in other ants in unpredictable environments. The growth of colonies was closely associated with resource abundance. Production of the male reproductive caste was closely tied to the size of a colony rather than growth, but male production in slow-growing colonies was limited. Colonies foraging within high-quality environments grew at a faster rate, but reproduction was mainly correlated with colony size. Furthermore, it was found that the frequency of foragers in long-term treatment plots with supplemental food and reduced leaf-litter quality was not significantly different from the frequency of foragers in control plots. This rain-forest ant does not modify its home range areas in response to poor environments, and as a result, small-scale environmental heterogeneity strongly determines growth and reproduction.

A new high-performance liquid chromatographic (HPLC) procedure for the determination of dexamethasone, imprities, degradation products and product preservatives is described. A three-stage, linear gradient with UV detection at 240 nm allows the alysis of dexamethasone drug substance and dexamethasone in two formulated products, using the same chromatographic system. The Limit of Quantitation (LOQ) of dexamethasone importies in drug substance is 0.05%, and 0.1% for dexamethasone degradation products in formulated products. The method is linear, precise, accurate and robust. Sample preparations are simiple, and are accomplished without the use of an internal standard. Several degradation products of stressed dexamethasone have been identified.

Within-plant height (leaf position) of European corn borer, Ostrinia nubilalis (Hubner) egg masses were analyzed in four sweet corn hybrids planted across four planting dates from 1994 to 1996. From the five-leaf to 15-leaf vegetative stages, the mean leaf position of an egg mass was typically at the midpoint of available (nonsenescent) leaves. The mean leaf position of egg masses gradually increased from early to late leaf stages as new leaves were added, and continued to increase during the first reproductive stage (green tassel). The increase in vertical position during vegetative stages was modeled as y = −0.766 + 0.653(x), where y = nodal leaf position, and x = total leaves expanded (r2 = 0.94). However, when the mean egg mass position was expressed as the mean position within available (expanded and nonsenescent) leaves, no relationship was found. These data indicate that during vegetative stages the mean egg mass position increases relative to ground level, but remains near the midpoint of...

Oviposition rates of the European corn borer, Ostrinia nubilalis (Hubner), were examined on corn plants from the 3-leaf through postharvest growth stages during 1994–1996. Per-plant rates in the field during vegetative stages showed a gradual increase as new leaves appeared, and a sharp increase when reproductive plant parts emerged. Laboratory studies indicated a similar relationship between oviposition rate and plant growth stage: significantly greater rates occurred on reproductive plants. Laboratory experiments showed that when only 4-leaf to early green tassel (preanthesis) plants were present (simulating conditions during early-season European corn borer activity), per-plant oviposition was significantly greater on the oldest (11-leaf to green tassel) plants. When the oviposition rate was based on leaf area rather than on a per-plant basis, however, statistical differences between vegetative stages were lost. When European corn borer females were given only reproductive plant stages (simulating conditions during late-season European corn borer oviposition), plants in the green tassel, anthesis, green silk, and brown silk stages had generally equal oviposition rates, and these were significantly greater than on postharvest plants. This European corn borer oviposition simulation, when based on leaf area, showed the same pattern as the per-plant oviposition. Thus, leaf area appears to influence oviposition during the vegetative stages, when leaf area is rapidly expanding, but is of little influence after tassels emerge and leaf area is expanding at a slower rate or declining. Moth alighting in the laboratory indicate a behavioral difference between sexes. Females alighted on plants identical to those favored for oviposition. In contrast, males showed no preference for any growth stage of corn.

Introduction:Many geographical areas are subject to devastating disasters that leave the citizens not only without homes, but also without their local medical systems. Now medical-aid stations consisting of personnel, supplies, and equipment quickly can be deployed when needed to such areas under the aegis of the National Disaster Medical System (NDMS). Such teams can provide emergent medical care as well as daily medical care. However, these aid stations are of no help for the home–bound or nursing home patients too infirm to reach them. Thus, these citizens only can obtain medical care if medical teams make planned outreach excursions to reach them.Objective:To describe a planned outreach program that was implemented for such patients on St. Thomas Island after it was devastated by Hurricane Marilyn in 1995.Results:Over a five-day period, the out-reach team provided medical care for 67 patients ranging in age from 11 days to 90 years. Play and art therapy was provided for non-injured children. The most common needs in the elderly were anti-hypertensive medications and insulin-loaded syringes.Conclusion:For outreach efforts of this nature, membership of the team should include a registered nurse, a paramedic, a respiratory therapist, a public health specialist, and a local authority familiar both with the area and its inhabitants. A physician does not need to be assigned to the team, but should be available by radio.

Pheromone disruptants were tested from 1989 to 1992 in western New York to determine effect on trap catch and potential use in the control of obliquebanded leafroller, Choristoneura rosaceana (Harris), using polyethylene tube tie and controlled-release membrane dispensers in plots of 0.2-2.4 ha. Effectiveness of pheromone at different application rates and canopy locations was evaluated using synthetic pheromone-baited traps, molasses-baited traps, and by inspecting foliar terminals and fruit for leafroller damage. All pheromone treatments significantly reduced (by 56-97%) pheromone trap catches of male moths compared with catches in nontreated blocks. One application of a natural-blend formulation at 988 dispensers per hectare was better than 494/ha at disrupting trap catch of both flights that occur during the year. However, mated female moths were present in the orchard center as frequently as anywhere else in a pheromone-treated block, indicating either immigration from outside sources or resident females that were not prevented from mating by the pheromone. The membrane dispenser emitted the 3-component natural blend at proportions similar to those in wild female moths. Pheromone traps placed in the tops of trees in a pheromone-treated orchard always caught higher numbers of male moths than those in lower- or middle-canopy positions. Pheromone treatment resulted in fruit damage similar to that of a pheromone + insecticide treatment under low to moderate leafroller population pressure (i.e., 3-5% fruit damage in untreated orchards) ; however, no control method was able to reduce damage to acceptable levels in all cases.

Previous studies have shown tortuous arteries and arterioles in the brains of older people, but the effects of age and other factors have not been studied. To examine the effects of hypertension, age, race and sex on white matter (WM) arteriolar tortuosity (AT), we performed high-resolution microradiography and morphometry of human brains taken at autopsy from 44 subjects of various ages (range 30-96 years; 31 hypertensives/13 normotensives). About 70% of tortuosities in the WM were found at the gray-white interfaces of the insular region and adjacent subcortical-WM of the inferior frontal and superior temporal gyri. Six morphologic types of tortuous profiles were identified. The number of tortuous profiles increased with age, but not significantly. Hypertension, sex and race had no effect on tortuosity. Our findings also suggest that 1) WM AT is found mostly at the interfaces between gray matter and WM and, therefore, 2) the physical properties of the WM somehow predispose to the development of AT; 3) AT is not associated with tortuosity in the veins; and 4) the location of complex arteriolar coils supports a recent claim that they can be mistaken for the Charcôt-Bouchard microaneurysms if injection of contrast media and low-magnification radiography of the brain slices are employed for that purpose.

BackgroundPseudomonas aeruginosais an important opportunisticpathogen causing serious pulmonary, urogenital and sys-temic infections. P. aeruginosa injects four effector pro-teins into host cells via the type III secretion system. ExoYis one of these proteins.ExoY was originally classified as adenylyl cyclase withhomology to the typical calmodulin-stimulated adenylylcyclase exotoxins CyaA fromBordetella pertussis andedema factor from Bacillus anthracis, but the pathophy-siologial function of ExoY has remained elusive [1,2].Recently, our group showed that CyaA and edema factorpossess a rather broad base specifity (ATP >> CTP >UTP) [3,4], raising the question of wether ExoY may alsobind and metabolize nucleoside 5’- triphosphates otherthan ATP.MethodsWe determined cyclic nucleotide concentrations in cellstransfected with ExoY plasmid or infected with P. aerugi-nosa with a highly sensitive HPLC-MS/MS method. More-over, we determined the catalytic activity of purified ExoY.ResultsIn mammalian cells transfected with ExoY plasmid andinfected with ExoY-encoding P. aeruginosa, massive pro-duction of cGMP and cUMP was observed, with littleproduction of cAMP. Purified ExoY was a highly effectivenucleotidyl cyclase with the substrate preference GTP >>UTP ~ ATP > CTP. Fluorescence resonance energytransfer studies with methylanthraniloyl-substitutednucleotides corroborated the preference of ExoY forGTP. In contrast to ExoY, CyaA induced accumulation

Seasonal densities of the tarnished plant bug, Lygus lineolaris (Palisot), and other phytophagous Heteroptera on canes of blackberry and raspberry, Rubus spp., were examined at thirteen plantings during 1988-1990 in central New York. At least 27 species were found; L. lineolaris, Plagiognathus politus Uhler, and P. Obscures Uhler were most common. In some plantings, Adelphocoris lineolatus (Goeze), Lygocoris caryae (Knight), pentatomids, and Kleidocerys resedae (Panzer) were also common. In summer-bearing brambles, L. lineolaris and Plagiognathus spp. had two major periods of abundance: (1) nymphs and adults from the late bloom through the “green fruit” stages, and (2) adults during the fruit-ripening stage. The first situation was less common in commercially managed plantings. ‘Heritage’ raspberries had few insects present during the floricane (summer) crop and high adult L. lineolaris populations during the primocane (fall) crop as the fruit ripened. Adults of L. lineolaris and other Heteroptera were significantly more abundant on raspberry canes with ripe fruit than on canes having unripe fruit. The insect populations on adjacent flowering and fruiting broadleaf weeds could be contributing Significantly to mirid densities on summer-bearing brambles before fruit ripens. The data indicate there are much larger nymphal heteropteran populations present on bramble canes than had been previously recorded, and that Heteroptera other than L. lineolaris , particularly Plagiognathus spp., are also abundant on bramble canes. Implications for bramble pest management are discussed.