Within-Year Effects of Prescribed Fire on Bumble Bees (Hymenoptera: Apidae) and Floral Resources.

Despite the importance of bumble bees (genus Bombus Latreille) for their services to natural and agricultural environments, we know little about the relationship between grassland management practices and bumble bee conservation. Prescribed fire is a common grassland maintenance tool, including in areas where endangered and threatened bumble bees are present. Thus, knowledge of the effects of prescribed fire on bumble bees is essential for designing management schemes that protect and bolster their populations. Using nonlethal surveys to record bumble bee species richness, abundance, and community composition, we evaluated the effects of spring controlled burns on summer bumble bee gynes and workers across five sites in southern Wisconsin. In addition, we explored the effects of fire on floral resources by measuring floral genus richness, abundance, ground cover, and proportion of transects containing blooming flowers in adjacent burned and unburned parcels. Prescribed fire had no measurable effects on bumble bee gyne or worker community composition, species richness, or abundance. However, consistent with previous studies prescribed fire increased floral genus richness and ground cover. The disconnect between bumble bee and floral responses to fire highlights some opportunities for improving our understanding of fire's effects on bumble bee diapause, nest site choice, and foraging.

Distinct Stages of Moment-to-Moment Processing in the Cinguloopercular and Frontoparietal Networks.

Control of goal-directed tasks is putatively carried out via the cinguloopercular (CO) and frontoparietal (FP) systems. However, it remains unclear whether these systems show dissociable moment-to-moment processing during distinct stages of a trial. Here, we characterize dynamics in the CO and FP networks in a meta-analysis of 5 decision-making tasks using fMRI, with a specialized "slow reveal" paradigm which allows us to measure the temporal characteristics of trial responses. We find that activations in left FP, right FP, and CO systems form separate clusters, pointing to distinct roles in decision-making. Left FP shows early "accumulator-like" responses, suggesting a role in pre-decision processing. CO has a late onset and transient response linked to the decision event, suggesting a role in performance reporting. The majority of right FP regions show late onsets with prolonged responses, suggesting a role in post-recognition processing. These findings expand upon past models, arguing that the CO and FP systems relate to distinct stages of processing within a trial. Furthermore, the findings provide evidence for a heterogeneous profile in the FP network, with left and right FP taking on specialized roles. This evidence informs our understanding of how distinct control networks may coordinate moment-to-moment components of complex actions.

Situating the parietal memory network in the context of multiple parallel distributed networks using high-resolution functional connectivity.

A principle of brain organization is that networks serving higher cognitive functions are widely distributed across the brain. One exception has been the parietal memory network (PMN), which plays a role in recognition memory but is often defined as being restricted to posteromedial association cortex. We hypothesized that high-resolution estimates of the PMN would reveal small regions that had been missed by prior approaches. High-field 7T functional magnetic resonance imaging (fMRI) data from extensively sampled participants was used to define the PMN within individuals. The PMN consistently extended beyond the core posteromedial set to include regions in the inferior parietal lobule; rostral, dorsal, medial, and ventromedial prefrontal cortex; the anterior insula; and ramus marginalis of the cingulate sulcus. The results suggest that, when fine-scale anatomy is considered, the PMN matches the expected distributed architecture of other association networks, reinforcing that parallel distributed networks are an organizing principle of association cortex.

Crop and Non-Crop Plants as Potential Reservoir Hosts of Alfalfa mosaic virus and Cucumber mosaic virus for Spread to Commercial Snap Bean.

Diseases caused by aphid-transmitted viruses such as Alfalfa mosaic virus (AMV) and Cucumber mosaic virus (CMV) have increased in snap bean (Phaseolus vulgaris) in the Midwestern United States. Plants immediately surrounding agricultural fields may serve as primary virus inocula for aphids to acquire and transmit to bean crops. The project objectives were to (i) identify potentially important AMV and CMV reservoirs among naturally infected plants and (ii) determine the relationship between the virus inoculum potential (VIP) in adjacent crop field margins and virus incidence in P. vulgaris. From 2006 to 2008, surveys were conducted to quantify the virus incidence and percentage cover (2008 only) of plants present within 5 m of the P. vulgaris crop. In all, 4,350 individual plants representing 44 species were assayed, with overall AMV and CMV incidences averaging 12 and 1.5%, respectively. A VIP index was developed and used to rank the importance of virus-susceptible plants in adjacent field margins. The overall VIP index for AMV in field margins was weakly associated with AMV incidence in P. vulgaris and no relationship was observed between local CMV inoculum and P. vulgaris incidence, suggesting that factors additional to local inoculum sources may influence CMV epidemics in P. vulgaris.

Soybean aphid and soybean cyst nematode interactions in the field and effects on soybean yield.

How above- and belowground plant pests interact with each other and how these interactions affect productivity is a relatively understudied aspect of crop production. Soybean cyst nematode, Heterodera glycines Ichinohe, a root parasite of soybean, Glycine max (L.) Merr., is the most threatening pathogen in soybean production and soybean aphid, Aphis glycines Matsumura, an aboveground phloem-feeding insect that appeared in North America in 2000, is the key aboveground herbivore of soybean in the midwestern United States. Now, both soybean aphid and soybean cyst nematode co-occur in soybean-growing areas in the Upper Midwest. The objectives of this study were to examine aphid colonization patterns and population growth on soybean across a natural gradient of nematode density (range, approximately 900 and 27,000 eggs per 100 cm3 soil), and to investigate the effect of this pest complex on soybean productivity. Alate (winged) soybean aphid colonization of soybean was negatively correlated to soybean cyst nematode egg density (r = -0.363, P = 0.0095) at the end of July, at the onset of peak alate colonization. However, both a manipulative cage study and openly colonized plants showed that soybean cyst nematode density below ground was unrelated to variation in aphid population growth (r approximately -0.01). Based on regression analyses, soybean aphids and cyst nematodes had independent effects on soybean yield through effects on different yield components. High soybean cyst nematode density was associated with a decline in soybean yield (kg ha(-1)), whereas increasing soybean aphid density (both alate and apterous) significantly decreased seed weight (g 100 seeds(-1)).

Seasonal phenology of Aphis glycines (Hemiptera: Aphididae) and other aphid species in cultivated bean and noncrop habitats in Wisconsin.

The occurrence of aphid-transmitted viruses in agricultural crops of the Midwest and northeastern United States has become more frequent since the arrival and establishment of the soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae). A. glycines is a competent vector of plant viruses and may be responsible for recent virus epidemics in Wisconsin snap bean, Phaseolus vulgaris L., fields. To determine whether vegetation surrounding crop fields could serve as sources of virus inocula, we examined the settling activity ofA. glycines and other aphid species in agricultural crops and noncrop field margins adjacent to snap bean fields. Noncrop field margins were made up of numerous virus-susceptible plant species within 10 m from snap bean field edges. During summers 2006 and 2007, horizontal pan traps were placed in commercial soybean [Glycine max (L.) Merr.], snap bean, and surrounding field margins to characterize aphid flight activity patterns in the different habitat types. Alate abundance and peak occurrence across years varied between crop and noncrop field margins and differed among patches of plants in field margins. Overall aphid activity peaked late in the season (21 August in 2006 and 28 July in 2007); with the majority (52%) of total aphids trapped in all habitats being A. glycines. Susceptibility to viral infection and confirmed visitation of A. glycines to these forage plants suggests the importance ofnoncrop habitats as potential sources of primary virus inoculum. Viral disease onset followed peak aphid flights and further implicates A. glycines as a likely vector of viruses in commercial bean and other crops in Wisconsin.

Landscape diversity enhances biological control of an introduced crop pest in the north-central USA.

Arthropod predators and parasitoids provide valuable ecosystem services in agricultural crops by suppressing populations of insect herbivores. Many natural enemies are influenced by non-crop habitat surrounding agricultural fields, and understanding if, and at what scales, land use patterns influence natural enemies is essential to predicting how landscape alters biological control services. Here we focus on biological control of soybean aphid, Aphis glycines Matumura, a specialist crop pest recently introduced to the north-central United States. We measured the amount of biological control service supplied to soybean in 26 replicate fields across Michigan, Wisconsin, Iowa, and Minnesota across two years (2005-2006). We measured the impact of natural enemies by experimentally excluding or allowing access to soybean aphid infested plants and comparing aphid population growth over 14 days. We also monitored aphid and natural enemy populations at large in each field. Predators, principally coccinellid beetles, dominated the natural enemy community of soybean in both years. In the absence of aphid predators, A. glycines increased significantly, with 5.3-fold higher aphid populations on plants in exclusion cages vs. the open field after 14 days. We calculated a biological control services index (BSI) based on relative suppression of aphid populations and related it to landscape diversity and composition at multiple spatial scales surrounding each site. We found that BSI values increased with landscape diversity, measured as Simpson's D. Landscapes dominated by corn and soybean fields provided less biocontrol service to soybean compared with landscapes with an abundance of crop and non-crop habitats. The abundance of Coccinellidae was related to landscape composition, with beetles being more abundant in landscapes with an abundance of forest and grassland compared with landscapes dominated by agricultural crops. Landscape diversity and composition at a scale of 1.5 km surrounding the focal field explained the greatest proportion of the variation in BSI and Coccinellidae abundance. This study indicates that natural enemies provide a regionally important ecosystem service by suppressing a key soybean pest, reducing the need for insecticide applications. Furthermore, it suggests that management to maintain or enhance landscape diversity has the potential to stabilize or increase biocontrol services.

Reducing Native Ant Abundance Decreases Predation Rates in Midwestern Grasslands.

Diverse and robust predator communities are important for effective prey suppression in natural and managed communities. Ants are ubiquitous components of terrestrial systems but their contributions to natural prey suppression is relatively understudied in temperate regions. Growing evidence suggests that ants can play a significant role in the removal of insect prey within grasslands, but their impact is difficult to separate from that of nonant predators. To test how ants may contribute to prey suppression in grasslands, we used poison baits (with physical exclosures) to selectively reduce the ant population in common garden settings, then tracked ant and nonant ground predator abundance and diversity, and removal of sentinel egg prey for 7 wk. We found that poison baits reduced ant abundance without a significant negative impact on abundance of nonant ground predators, and that a reduction in ant abundance decreased the proportion of sentinel prey eggs removed. Even a modest decrease (~20%) in abundance of several ant species, including the numerically dominant Lasius neoniger Emery (Hymenoptera: Formicidae), significantly reduced sentinel prey removal rates. Our results suggest that ants disproportionately contribute to ground-based predation of arthropod prey in grasslands. Changes in the amount of grasslands on the landscape and its management may have important implications for ant prevalence and natural prey suppression services in agricultural landscapes.

Wada memory testing and hippocampal volume measurements in the evaluation for temporal lobectomy.

We examined the relationship of Wada memory performance and MRI hippocampal volume measurements to laterality of ultimate seizure localization in 20 patients with complex partial seizures who later underwent temporal lobectomy. Discriminant function analysis employing both Wada memory test asymmetries and hippocampal volume asymmetries correctly classified 100% of the patients into left and right temporal lobe groups. Wada memory asymmetries alone correctly classified 90% of the sample (80% of the sample when the discriminant function included all patients except the one being classified), and hippocampal volume asymmetries alone correctly classified 90% of the patients. A significant correlation was present between Wada memory asymmetries and hippocampal volume asymmetries (r = 0.78), indicating that structural evidence of reduced hippocampal volume has a functional correlate reflected by Wada memory performance. These data suggest that the combination of functional and structural measures is of value in the preoperative evaluation for epilepsy surgery.

Advocacy and rationing are compatible.

In his paper, Peter Ubel attempts to make the case for "bedside rationing" by clinicians in order to help control healthcare costs. This commentary addresses a number of conceptual, logical and linguistic problems with Dr. Ubel's paper, challenges his apparently "heretical" view of advocacy, but provides additional support for his central claim that physicians should do bedside rationing.

Fine-needle breast aspiration biopsy.

Fine-needle aspiration biopsy of breast lesions is a safe, accurate, well-tolerated procedure that can easily be done in the family physician's office. It has a specificity and positive predictive value of virtually 100 percent, a sensitivity of 53 to 99 percent (median of 89 percent), and a negative predictive value of 80 to 99 percent (median of 93 percent). It is limited by the nature of the lesion, which must be easily palpable, the physician's technical ability, and the availability of a reference cytopathologist. Complications are rare and usually very benign, such as local hematoma. With proper training and understanding of the procedure, many family physicians could easily introduce the procedure into their office practice.

Letting and making death happen, withholding and withdrawing life-support: morally irrelevant distinctions.

The author argues that there is no morally relevant distinction between letting and making death happen, and between withholding and withdrawing life-support. There is a discussion of possible adverse consequences in believing that there are moral distinctions. And then he shows that acknowledging the absence of such a distinction does not necessarily imply any endorsement of active euthanasia.

Measuring natural pest suppression at different spatial scales affects the importance of local variables.

The role biodiversity plays in the provision of ecosystem services is widely recognized, yet few ecological studies have identified characteristics of natural systems that support and maintain ecosystem services. The purpose of this study was to identify landscape variables correlated with natural pest suppression carried out by arthropod natural enemies, predators and parasitoids. We conducted two field experiments, one observational and one experimental, where landscape variables at broad and local scales were measured and related to natural pest suppression. The first experiment measured natural pest suppression at 16 sites across an urban to rural landscape gradient in south central Wisconsin. We found natural enemy diversity positively affected natural pest suppression, whereas flower diversity negatively affected pest suppression. No relationship was found between natural pest suppression and broad scale variables, which measured the percentage of different land cover classes in the surrounding landscape. In the second experiment, we established small (2- by 3-m) replicated plots that experimentally varied flower diversity (0, 1, or 7 species) within a plot. We found no significant relationship between natural pest suppression and the different levels of flower diversity. The fact that we only found differences in natural pest suppression in our first experiment, which measured natural pest suppression at sites separated by larger distances than our second experiment, suggests the more appropriate scale for measuring ecosystem services performed by mobile organisms like insects, is across broad spatial scales where variation in natural enemies communities and the factors that affect them become more apparent.

Soybean cyst nematode effects on soybean aphid preference and performance in the laboratory.

Herbivores on plants frequently interact via shared resources. Studies that have examined performance of herbivores in the presence of other herbivores, however, have often focused on above-ground feeding guilds and relatively less research has examined interactions between below- and above-ground consumers. We examine how soybean aphid, Aphis glycines (Matsumura) an above-ground phloem-feeding herbivore, interacts with a below-ground plant parasite, soybean cyst nematode, Heterodera glycines (Ichinohe) through their shared host plant, soybean (Glycine max L). Laboratory experiments evaluated the preference of alate (flight-capable) soybean aphids toward plants either infected with soybean cyst nematode or uninfected controls in a simple choice arena. Alate soybean aphids preferred uninfected soybean over soybean cyst nematode-infected plants: 48 h after the releases of alate aphids in the center of the arena, 67% more aphids were found on control soybean compared with nematode infected plants. No-choice feeding assays were also conducted using clip cages and apterous (flight-incapable) aphids to investigate effect of soybean cyst nematode infection of soybean on aphid performance. These studies had mixed results: in one set of experiments overall aphid population growth at 7 d was not statistically different between control and soybean cyst nematode-infected plants. A different experiment using a life-table analysis found that apterous aphids feeding on soybean cyst nematode-infected plants had significantly greater finite rate of increase (λ), intrinsic rate of increase (r(m)), and net reproductive rate (R(o)) compared with aphids reared on uninfected (control) soybean plants. We conclude that the below-ground herbivore, soybean cyst nematode, primarily influences soybean aphid behavior rather than performance.

Postnatal changes in testicular gonadotropin receptors, serum gonadotropin, and testosterone concentrations and functional development of the testes in bulls.

The primary objectives of this study were to follow the temporal patterns of testicular LH and FSH receptor (LH-R and FSH-R) concentrations and affinity (Ka) during sexual maturation in bulls and to see if such patterns could help explain the control of rapid testicular growth that occurs after 25 weeks of age, when serum gonadotropin concentrations are low. Separate groups of Hereford x Charolais calves (n = 6) were castrated every 4 weeks from 5 to 33 weeks of age and at 56 weeks of age. A week prior to castrations, from 5 to 33 weeks of age, blood was collected every 15 min for 10 h. The transition from indifferent supporting cells to Sertoli cells in seminiferous tubules was rapid between 13 and 25 weeks and rapid testis growth occurred after 25 weeks of age. Serum LH and FSH concentrations were transiently elevated at 12 weeks of age (P < 0.05). LH-R concentrations decreased from 13 to 25 weeks of age and increased to 56 weeks of age (P < 0.05). LH-RKa decreased from 9 to 17 weeks of age, increased to 29 weeks of age and declined to 33 weeks of age (P < 0.05). FSH-R concentrations declined from 17 to 25 weeks of age then increased to 56 weeks of age (P < 0.05). FSH-RKa increased from 17 to 25 weeks of age (P < 0.05). High concentrations of gonadotropins and their receptors may be critical to initiate testis growth postnatally and support it after 25 weeks of age in the face of low serum gonadotropin concentrations.

Urine screening with the MS-2.

A study was undertaken to evaluate the effectiveness of the MS-2 (Abbott Laboratories, Dallas, Tex.) in screening urine specimens in a large clinical laboratory. A total of 15,319 urine specimens (9,954 midstream specimens and 5,365 catheter specimens) were evaluated with the MS-2 and by a surface streak procedure. The study was conducted in two phases, differing in that phase II urine specimens were evaluated in the MS-2 by using a program software update (03.01). For midstream urine specimens, MS-2 detection rates in phases I and II were, respectively, 94.5 and 94.3% at a plate count of greater than 10(5) CFU/ml, 74.4 and 65.3% at plate counts of 5 X 10(4) to 1 X 10(5) CFU/ml, 55.0 and 52.4% at plate counts of 1 X 10(4) to 5 X 10(4) CFU/ml, 31.2 and 20.5% at plate counts of 10(3) to 10(4) CFU/ml, and 15.7 and 6.4% at plate counts of less than 10(3) CFU/ml. For catheter urine specimens, the MS-2 detection rates in phases I and II were, respectively, 95.4 and 96.8% at plate counts greater than 10(5) CFU/ml, 74.4 and 85.7% at plate counts of 5 X 10(4) to 1 X 10(5) CFU/ml, 50.0 and 44.4% at plate counts 10(4) to 5 X 10(4) CFU/ml, 25.6 and 14.9% at plate counts of 10(3) to 10(4) CFU/ml, and 14.7 and 5.2% at plate counts less than 10(3) CFU/ml.

Comparison of a DNA probe with culture for detecting Chlamydia trachomatis directly from genital specimens.

A study was conducted to compare results between culture methods and the Gen-Probe (Gen-Probe Inc. San Diego, California) chemiluminescent technique of nucleic acid hybridization to identify Chlamydia trachomatis from genital specimens from 117 females and 70 males. Specimens collected from sexually transmitted diseases (STD) and infertility clinics were randomized as to whether probe or culture swabs were collected first. The Gen-Probe demonstrated a sensitivity of 83% and a specificity of 75% in the female population and a sensitivity of 68% and a specificity of 75% in the male population when compared to the reference culture method using cycloheximide-treated McCoy cells. Gen-Probe had an overall sensitivity of 74% and specificity of 75% when the two groups were combined. Chlamydiazyme (Abbott Labs) results were obtained on 135 specimens; 90 of which correlated with probe and culture. The remaining 45 specimens had varying combinations of probe, culture and Chlamydiazyme results. MicroTrak (Syva) was done on 49 specimens; 35 of which correlated with probe and culture. The remaining 14 specimens had varying combinations of probe, culture and MicroTrak results. The apparent lack of sensitivity of the DNA probe is a major drawback of this system.

Bacteremia due to Bacteroidacceae: a review of 92 cases.

The clinical courses of 92 patients who had bacteremia due to Bacteroidaceae were reviewed. The overall mortality rate was 21% (19 patients). There was no significant difference between mortality rates when patients were grouped by anticipated clinical course of underlying disease (nonfatal, ultimately fatal, and rapidly fatal) and when they were grouped by type of antibacterial therapy (appropriate, including clindamycin, chloramphenicol, lincomycin, and carbenicillin; or inappropriate, signifying no antibiotic treatment or treatment with antibiotics other than the four listed above). However, there was a correlation between recovery of the patient and portal of entry of the infectious agent; patients whose source of infection was the gastrointestinal tract had a mortality rate of 29% (17 of 58 patients), whereas there were no deaths among the 26 women whose presumed source of bacteremia was the genital tract. Increasing age appeared to be an important factor as well; 17 of 19 deaths occurred in patients who were older than 40 years. There was no significant difference between the mortality rate of patients who were treated with clindamycin (15%, eight of 52 patients) and that of patients who were treated with chloramphenicol (44%, four of nine).