Farm management and landscape context shape plant diversity at wetland edges in the Prairie Pothole Region of Canada.

Evaluating the impacts of farming systems on biodiversity is increasingly important given the need to stem biodiversity loss, decrease fossil fuel dependency, and maintain ecosystem services benefiting farmers. We recorded woody and herbaceous plant species diversity, composition, and abundance in 43 wetland-adjacent prairie remnants beside crop fields managed using conventional, minimum tillage, organic, or perennial cover (wildlife-friendly) land management in the Prairie Pothole Region. We used a hierarchical framework to estimate diversity at regional and local scales (gamma, alpha), and how these are related through species turnover (beta diversity). We tested the expectation that gamma richness/evenness and beta diversity of all plants would be higher in remnants adjacent to perennial cover and organic fields than in conventional and minimum tillage fields. We expected the same findings for plants providing ecosystem services (bee-pollinated species) and disservices (introduced species). We predicted similar relative effects of land management on alpha diversity, but with the expectation that the benefits of organic farming would decrease with increasing grassland in surrounding landscapes. Gamma richness and evenness of all plants were highest for perennial cover, followed by minimum tillage, organic, and conventional sites. Bee-pollinated species followed a similar pattern for richness, but for evenness organic farming came second, after perennial cover sites, followed by minimum tillage and conventional. For introduced species, organic sites had the highest gamma richness and evenness. Grassland amount moderated the effect of land management type on all plants and bee-pollinated plant richness, but not as expected. The richness of organic sites increased with the amount of grassland in the surrounding landscape. Conversely, for conventional sites, richness increased as the amount of grassland in the landscape declined. Our results are consistent with the expectation that adopting wildlife-friendly land management practices can benefit biodiversity at regional and local scales, in particular the use of perennial cover to benefit plant diversity at regional scales. At more local extents, organic farming increased plant richness, but only when sufficient grassland was available in the surrounding landscape; organic farms also had the highest beta diversity for all plants and bee-pollinated plants. Maintaining native cover in agroecosystems, in addition to low-intensity farming practices, could sustain plant biodiversity and facilitate important ecosystem services.

Ride-Hailing and Road Traffic Crashes: A Critical Review.

Ride-hailing businesses, including Uber and Lyft, have reshaped road traffic since they first began operating in the United States approximately a decade ago. It follows that ride-hailing may also alter the incidence and distribution of road traffic crash injuries and deaths. The available evidence relating ride-hailing to crashes is critically reviewed in this article. We present a theoretical model that synthesizes the hypothesized mechanisms, and we identify common methodological challenges and suggest priorities for future research. Mixed results have been reported for the overall incidence of road traffic crash injuries and deaths, likely due to heterogeneous impacts on vehicular traffic flow (e.g., increasing the volume of vehicles); on vehicle-, person-, and event-level characteristics (e.g., reducing alcohol-impaired driver crashes); on road-user types (e.g., increasing pedestrian crashes); and on environmental conditions (e.g., reducing crashes most substantially where public transit access is poorest). The lack of a well-developed theory of human mobility and methodological challenges that are common to many ecological studies impede exploration of these sources of moderation. Innovative solutions are required to explicate ride-hailing's heterogeneous impacts, to guide policy that can take advantage of the public health benefits of ride-hailing, and to ensure that research keeps pace with technological advances that continue to reshape road traffic use.

An audit experiment to investigate the "war on cops": a research note.

Objectives: This study examines whether former police officers are stigmatized in the labor market, particularly following social unrest from lethal police violence. Methods: We conduct an experimental audit study, both before and after heightened unrest from police violence. For service-related job openings, we compare the likelihood of getting an affirmative response from a prospective employer to a job application from a fictitious former police officer (the treatment condition) to the response to one of two control conditions: a former firefighter or a former code enforcement officer. Results: We do not find evidence that former police officers are discriminated against in the labor market. This finding holds in periods characterized by relatively little social unrest due to police violence as well as periods of heightened protest activity. Conclusions: At least with respect to the labor market for certain service-related professions, former police officers do not appear tainted by any stigma associated with their prior profession. Supplementary Information: The online version contains supplementary material available at 10.1007/s11292-021-09458-x.

Impact of heat stress and a feed supplement on hormonal and inflammatory responses of dairy cows.

The aim of this trial was to evaluate the effects of an immunomodulatory supplement (OmniGen AF, OG; Phibro Animal Health Corp.) and heat stress on hormonal, inflammatory, and immunological responses of lactating dairy cows. Sixty multiparous Holstein cows were randomly assigned to 4 treatments in a 2 × 2 factorial arrangement using 2 environments: cooled using fans and misters, or noncooled, and 2 top-dressed feed supplements (56 g/d): OG or a placebo (CTL). Temperature-humidity index averaged 78 during the 8-wk trial. Blood was drawn to analyze cortisol, prolactin, and circulating tumor necrosis factor (TNF)-α and IL-10. Peripheral blood mononuclear cells (PBMC) were isolated and stimulated with hydrocortisone, prolactin, or lipopolysaccharide (LPS), individually or in several combinations, to assess induced proliferation and cytokine production. At d 52, 6 cows per treatment were injected i.v. with an LPS bolus (ivLPS) to assess hormone and cytokine responses. For cooled cows, feeding OG increased plasma cortisol concentration relative to CTL. Noncooled cows fed CTL had lower circulating TNF-α concentrations than noncooled-OG and cooled-CTL cows, with cooled-OG intermediate. Hydrocortisone+LPS-stimulated PBMC from OG cows tended to proliferate more than CTL. Relative to cooled cows, PBMC from noncooled cows produced more TNF-α and IL-10 when stimulated with LPS. Following ivLPS, cooled-OG cows had a greater cortisol response than the other treatments. In conclusion, OG supplementation enhanced cortisol release under basal condition and induced inflammation with cooling compared with CTL. This suggests that heat stress inhibits OG-mediated cortisol release. Heat stress seemed to enhance the inflammatory responses of PBMC from lactating cows. However, OG supplementation promoted PBMC proliferation under stress, or in the presence of hydrocortisone.

A natural experiment of the consequences of concentrating former prisoners in the same neighborhoods.

More than 600,000 prisoners are released from incarceration each year in the United States, and most end up residing in metropolitan areas, clustered within a select few neighborhoods. Likely consequences of this concentration of returning prisoners include higher rates of subsequent crime and recidivism. In fact, one-half of released prisoners return to prison within only 3 y of release. The routine exposure to criminogenic influences and criminal opportunities portends a bleak future for individuals who reside in neighborhoods with numerous other ex-prisoners. Through a natural experiment focused on post-Hurricane Katrina Louisiana, I examine a counterfactual scenario: If instead of concentrating ex-prisoners in geographic space, what would happen to recidivism rates if ex-prisoners were dispersed across space? Findings reveal that a decrease in the concentration of parolees in a neighborhood leads to a significant decrease in the reincarceration rate of former prisoners.

Effects of halogenated contaminants on reproductive development in wild mink (Neovison vison) from locations in Canada.

The concept of the Anthropocene, that humans are now re-engineering global ecosystems, is in part evidenced by the pervasive pollution by persistent organic pollutants (POPs). Certain POPs are hormone mimics and can disrupt endocrine and hence reproductive processes, shown mainly by laboratory studies with model species. There are, in contrast, fewer confirmations of such disruption from eco-epidemiological studies of wild mammals. Here we used the American mink (Neovison vison) as a sentinel species for such a study. Over the period 1998-2006, 161 mink carcasses were obtained from commercial trappers in the Canadian provinces of British Columbia and Ontario. Mink were aged, sexed, measured, and body condition assessed. Livers were analyzed either individually or pooled for organochlorine (OC) pesticides, polychlorinated biphenyls (PCBs), and subsets for polybrominated diphenyl ethers (PBDEs). We primarily addressed whether contaminants affected male reproductive development by measuring baculum size and assessing the influences of age and body condition. We also considered the influence of spatial variation on relative exposure and size of baculum. Statistical models separated by age class revealed that significant relationships between baculum length or mass and juvenile mink were mostly positive, whereas for adults and first year mink they were mostly negative. A significant negative relationship for adult mink was determined between DDE and both baculum length and mass. For juvenile mink we found significant positive relationships between ∑PCBs, DDE and ∑PBDEs with baculum length. Our results provide some indication of negative effects of halogenated contaminants on male reproductive development in wild mink, and the most likely candidate chemical is the confirmed anti-androgenic compound, DDE, rather than PCBs or other compounds.

The impact of residential change and housing stability on recidivism: pilot results from the Maryland Opportunities through Vouchers Experiment (MOVE).

OBJECTIVES: This article provides a description and preliminary assessment of the Maryland Opportunities through Vouchers Experiment (MOVE), a randomized housing mobility program for former prisoners designed to test whether residential relocation far away from former neighborhoods, incentivized through the provision of a housing subsidy, can yield reductions in recidivism. METHODS: The MOVE program was implemented as a randomized controlled trial. Participants were recruited from four different Maryland prisons and randomly assigned to experimental groups. In the first iteration of the experiment, treatment group participants received 6 months of free housing away from their home jurisdiction and control group participants received free housing back in their home jurisdiction. In the second iteration of the experiment, the treatment group remained the same and the control condition was redesigned to represent the status quo and did not receive free housing. Analyses were conducted of one-year rearrest rates. RESULTS: With respect to reductions in recidivism, pilot results suggest that there is some benefit to moving and a benefit to receiving free housing. Rearrest was lower among the treatment group of movers than the non-movers, and was also lower for non-movers who received free housing versus non-movers who did not receive housing. CONCLUSIONS: To the extent that pilot results can be validated and replicated in a full-scale implementation of the MOVE program, policies that provide greater access to housing assistance for formerly incarcerated individuals may yield substantial public safety benefits, particularly housing opportunities located far away from former neighborhoods.

Effects of feeding an immunomodulatory supplement to heat-stressed or actively cooled cows during late gestation on postnatal immunity, health, and growth of calves.

Heat stress during late gestation negatively affects the physiology, health, and productivity of dairy cows as well as the calves developing in utero. Providing cows with active cooling devices, such as fans and soakers, and supplementing cows with an immunomodulating feed additive, OmniGen-AF (OG; Phibro Animal Health Corporation), improves immune function and milk yield of cows. It is unknown if maternal supplementation of OG combined with active cooling during late gestation might benefit the developing calf as well. Herein we evaluated markers of innate immune function, including immune cell counts, acute phase proteins, and neutrophil function, of calves born to multiparous dams in a 2 × 2 factorial design. Dams were supplemented with OG or a bentonite control (NO) beginning at 60 d before dry off and exposed to heat stress with cooling (CL) or without active cooling (HT) during the dry period (∼46 d). At birth, calves were separated from their dams and fed 6.6 L of their dams' colostrum in 2 meals. Calf body weight and rectal temperature were recorded, and blood samples were collected at birth (before colostrum feeding) and at 10, 28, and 49 d of age. Calves born to either CL dams or OG dams were heavier at birth than calves born to HT or NO dams, respectively. Concentrations of serum amyloid A were higher in the blood of calves born to OG dams relative to NO and for HT calves relative to CL calves. In addition, calves born to cooled OG dams had greater concentrations of plasma haptoglobin than calves born to cooled control dams. Neutrophil function at 10 d of age was enhanced in calves born to cooled OG dams and lymphocyte counts were higher in calves born to OG dams. Together these results suggest that adding OG to maternal feed in combination with active cooling of cows during late gestation is effective in mitigating the negative effects of in utero heat stress on postnatal calf growth and immune competence.

Effect of nutritional immunomodulation and heat stress during the dry period on subsequent performance of cows.

Heat stress in dairy cows during the dry period impairs milk yield in the next lactation. Feeding OmniGen-AF (OG; Phibro Animal Health Corp., Teaneck, NJ) to lactating cows during heat stress may increase dry matter intake (DMI) and lowers respiration rate (RR) and rectal temperature (RT), but the effects in dry cows are not known. We hypothesized that OG supplementation before, during, and after the dry period (approximately 160 d total) would overcome the effects of heat stress and improve cow performance in the next lactation. Cows were randomly assigned to OG or control (placebo) treatments for the last 60 d in milk (DIM), based on mature-equivalent milk yield in the previous lactation. Cows were dried off 45 d before expected calving and randomly assigned to heat stress (HT) or cooling (CL) treatments. Thus, cows received dietary supplementation during late lactation before they were exposed to either CL or HT. After dry-off, treatment groups included heat stress with placebo (HT, only shade, 56 g/d of placebo, n = 17), HT with OG supplementation (HTOG, 56 g/d of OG, n = 19), cooling with placebo (CL, shade, fans, and soakers, 56 g/d of placebo, n = 16), and CL with OG supplementation (CLOG, 56 g/d of OG, n = 11). After parturition, all cows were kept under the same CL system and management, and all cows continued to receive OG or control treatment until 60 DIM. Cooling cows during the dry period reduced afternoon RT (CL vs. HT; 38.9 ± 0.05 vs. 39.3 ± 0.05°C) and RR (CL vs. HT; 45 ± 1.6 vs. 77 ± 1.6 breaths/min). Respiration rate was also decreased by OG supplementation under HT conditions (HTOG vs. HT; 69.7 ± 1.6 vs. 77.2 ± 1.6 breaths/min). An interaction was observed between OG supplementation and HT; HTOG cows tended to have lower morning RT compared with HT cows. During the dry period, OG reduced DMI relative to control cows. Birth weight was greater in calves from CL cows (CL vs. HT; 40.6 ± 1.09 vs. 38.7 ± 1.09 kg). No differences were detected among treatments in hematocrit, total protein, and body condition score. Cows offered CLOG, CL, and HTOG treatments had greater body weight during the dry period (794.9 ± 17.9, 746.8 ± 16.7, and 762.9 ± 14.9 kg, respectively) than HT cows (720 ± 16.2 kg). Gestation length was approximately 4 d longer for CL cows compared with HT cows. Cows offered CLOG, CL, and HTOG treatments produced more milk (41.3 ± 1.6, 40.7 ± 1.6, and 40.5 ± 1.6 kg/d, respectively) than HT treatment (35.9 ± 1.6 kg/d). Body weight after parturition and DMI were evaluated up to 60 DIM and averaged 661.5 ± 15.8 and 19.4 ± 0.7 kg/d, respectively, with no differences observed among treatments. These results confirm that exposure of dry cows to heat stress negatively affects milk yield in the subsequent lactation. Active cooling of dry cows and OG supplementation can reduce the negative effects of heat stress in the dry period on subsequent performance.

Silence Speaks: The Relationship between Immigration and the Underreporting of Crime.

Scarce in criminological literature is an exploration of whether crime reporting varies geographically. Yet, there are substantive reasons to believe not only that the percentage of crimes reported to the police varies across jurisdictions, but also that crime reporting can be explained by ecological characteristics. Drawing upon data from both the National Crime Victimization Survey and the census, this study examines the relationship between immigration and the likelihood that crimes are reported to the police. Results indicate that crime reporting is inversely related to increases in the rates of noncitizens and foreign-born residents within a metropolitan area, and that the negative effect is greater for violence than for property crime. Implications for policing and public safety are discussed.

Uber and Metropolitan Traffic Fatalities in the United States.

Uber and similar rideshare services are rapidly dispersing in cities across the United States and beyond. Given the convenience and low cost, Uber has been characterized as a potential countermeasure for reducing the estimated 121 million episodes of drunk driving and the 10,000 resulting traffic fatalities that occur annually in the United States. We exploited differences in the timing of the deployment of Uber in US metropolitan counties from 2005 to 2014 to test the association between the availability of Uber's rideshare services and total, drunk driving-related, and weekend- and holiday-specific traffic fatalities in the 100 most populated metropolitan areas in the United States using negative binomial and Poisson regression models. We found that the deployment of Uber services in a given metropolitan county had no association with the number of subsequent traffic fatalities, whether measured in aggregate or specific to drunk-driving fatalities or fatalities during weekends and holidays.

A population model of the impact of a rodenticide containing strychnine on Great Basin Gophersnakes (Pituophis catenifer deserticola).

Strychnine is a neurotoxin and an active ingredient in some rodenticides which are placed in burrows to suppress pocket gopher (Thomomys talpoides) populations in range and crop land in western North America. The population level impact was modelled of the use of strychnine-based rodenticides on a non-target snake species, the Great Basin Gophersnake (Pituophis catenifer deserticola), which is a predator of pocket gopher and a Species at Risk in Canada. Using information on population density, demographics, and movement and habitat suitability for the Gophersnake living in an agricultural valley in BC, Canada, we estimated the impact of the poisoning of adult snakes on the long-term population size. To determine the area where Gophersnakes could be exposed to strychnine, we used vendor records of a rodenticide, and quantified the landcover areas of orchards and vineyards where the compound was most commonly applied. GIS analysis determined the areas of overlap between those agricultural lands and suitable habitats used by Gophersnakes. Stage-based population matrix models revealed that in a low density (0.1/ha) population scenario, a diet of one pocket gopher per year wherein 10 % of them carried enough strychnine to kill an adult snake could cause the loss of 2 females annually from the population and this would reduce the population by 35.3 % in 25 years. Under the same dietary exposure, up to 35 females could die per year in a high density (0.4/ha) population which would result in a loss of 50 % of adults in 25 years.

Whole-body scanning PCR; a highly sensitive method to study the biodistribution of mRNAs, noncoding RNAs and therapeutic oligonucleotides.

Efficient tissue-specific delivery is a crucial factor in the successful development of therapeutic oligonucleotides. Screening for novel delivery methods with unique tissue-homing properties requires a rapid, sensitive, flexible and unbiased technique able to visualize the in vivo biodistribution of these oligonucleotides. Here, we present whole body scanning PCR, a platform that relies on the local extraction of tissues from a mouse whole body section followed by the conversion of target-specific qPCR signals into an image. This platform was designed to be compatible with a novel RT-qPCR assay for the detection of siRNAs and with an assay suitable for the detection of heavily chemically modified oligonucleotides, which we termed Chemical-Ligation qPCR (CL-qPCR). In addition to this, the platform can also be used to investigate the global expression of endogenous mRNAs and non-coding RNAs. Incorporation of other detection systems, such as aptamers, could even further expand the use of this technology.

Mercury in Forage Fish from Mexico and Central America: Implications for Fish-Eating Birds.

Mercury (Hg) is a global contaminant of aquatic food chains. Aquatic birds, such as the osprey (Pandion haliaetus), with migratory populations breeding in Canada and the northern United States and wintering in the Central and South America, can be exposed to mercury on both the breeding and wintering ranges. We examined Hg levels in 14 fish taxa from 24 osprey wintering sites identified from satellite telemetry. Our main goal was to determine whether fish species that feature in the diet of overwintering and resident fish-eating birds reached toxicity thresholds for Hg. Mean Hg levels in fish whole carcasses ranged from a high of 0.18 µg g(-1) (wet weight) in Scomberomorus sierra to a low of 0.009 µg g(-1) in Catostomidae. Average Hg levels were within published toxicity threshold values in forage fish for only two sites in Mexico (Puerto Vallarta and San Blas Estuary), and all were marine species, such as mackerel (Scomberomorus sierra), sea catfish (Ariopus spp.), and sardinas species (Centropomus spp.). Except for one sample from Nicaragua, sea catfish from Puerto Morazan, none of the fish from sites in Central America had Hg levels which exceeded the thresholds. Nonmetric multidimensional scaling revealed geographical differences in Hg levels with significant pairwise differences between sites along the Pacific Ocean (Mexico) versus the Bay of Campeche, partly due to differences in species composition of sampled fish (and species distributions). Hg increased with trophic level, as assessed by nitrogen stable isotope ratios (δ(15)N but not δ(13)C), in freshwater and marine, but not estuarine, environments. Hg concentrations in forage fish do not account for the elevated Hg reported for many osprey populations on the breeding grounds, thus primary sources of contamination appear to be in the north.

Runtime and Architecture Support for Efficient Data Exchange in Multi-Accelerator Applications.

Heterogeneous parallel computing applications often process large data sets that require multiple GPUs to jointly meet their needs for physical memory capacity and compute throughput. However, the lack of high-level abstractions in previous heterogeneous parallel programming models force programmers to resort to multiple code versions, complex data copy steps and synchronization schemes when exchanging data between multiple GPU devices, which results in high software development cost, poor maintainability, and even poor performance. This paper describes the HPE runtime system, and the associated architecture support, which enables a simple, efficient programming interface for exchanging data between multiple GPUs through either interconnects or cross-node network interfaces. The runtime and architecture support presented in this paper can also be used to support other types of accelerators. We show that the simplified programming interface reduces programming complexity. The research presented in this paper started in 2009. It has been implemented and tested extensively in several generations of HPE runtime systems as well as adopted into the NVIDIA GPU hardware and drivers for CUDA 4.0 and beyond since 2011. The availability of real hardware that support key HPE features gives rise to a rare opportunity for studying the effectiveness of the hardware support by running important benchmarks on real runtime and hardware. Experimental results show that in a exemplar heterogeneous system, peer DMA and double-buffering, pinned buffers, and software techniques can improve the inter-accelerator data communication bandwidth by 2×. They can also improve the execution speed by 1.6× for a 3D finite difference, 2.5× for 1D FFT, and 1.6× for merge sort, all measured on real hardware. The proposed architecture support enables the HPE runtime to transparently deploy these optimizations under simple portable user code, allowing system designers to freely employ devices of different capabilities. We further argue that simple interfaces such as HPE are needed for most applications to benefit from advanced hardware features in practice.

Alternative sigma factors SigF, SigE, and SigG are essential for sporulation in Clostridium botulinum ATCC 3502.

Clostridium botulinum produces heat-resistant endospores that may germinate and outgrow into neurotoxic cultures in foods. Sporulation is regulated by the transcription factor Spo0A and the alternative sigma factors SigF, SigE, SigG, and SigK in most spore formers studied to date. We constructed mutants of sigF, sigE, and sigG in C. botulinum ATCC 3502 and used quantitative reverse transcriptase PCR and electron microscopy to assess their expression of the sporulation pathway on transcriptional and morphological levels. In all three mutants the expression of spo0A was disrupted. The sigF and sigE mutants failed to induce sigG and sigK beyond exponential-phase levels and halted sporulation during asymmetric cell division. In the sigG mutant, peak transcription of sigE was delayed and sigK levels remained lower than that in the parent strain. The sigG mutant forespore was engulfed by the mother cell and possessed a spore coat but no peptidoglycan cortex. The findings suggest that SigF and SigE of C. botulinum ATCC 3502 are essential for early sporulation and late-stage induction of sigK, whereas SigG is essential for spore cortex formation but not for coat formation, as opposed to previous observations in B. subtilis sigG mutants. Our findings add to a growing body of evidence that regulation of sporulation in C. botulinum ATCC 3502, and among the clostridia, differs from the B. subtilis model.

The CLO3403/CLO3404 two-component system of Clostridium botulinum E1 Beluga is important for cold shock response and growth at low temperatures.

In order to survive a temperature downshift, bacteria have to sense the changing environment and adjust their metabolism and structure. Two-component signal transduction systems (TCSs) play a central role in sensing and responding to many different environmental stimuli. Although the nonproteolytic (group II) Clostridium botulinum represents a major hazard in chilled foods, the cold adaption mechanisms of group II C. botulinum organisms are not known. Here, we show that the CLO3403/CLO3404 TCS of C. botulinum E1 Beluga is involved in the cold shock response and growth at 12°C. Cold shock induced the expression of the genes encoding the histidine kinase (clo3403) and the response regulator (clo3404) by more than 100-fold after 5 h relative to their expression in a nonshocked culture at the corresponding time point. The involvement of CLO3403/CLO3404 in growth at low temperature was demonstrated by impaired growth of the insertional clo3403 and clo3404 knockout mutants at 12°C compared to the growth of the wild-type culture. Additionally, the inactivation of clo3403 had a negative effect on motility. The growth efficiency at 12°C of the TCS mutants and the motility of the kinase mutants were restored by introducing a plasmid harboring the operon of the CLO3403/CLO3404 TCS. The results suggest that the CLO3403/CLO3404 TCS is important for the cold tolerance of C. botulinum E1 Beluga.

Evaluation of normalization reference genes for RT-qPCR analysis of spo0A and four sporulation sigma factor genes in Clostridium botulinum Group I strain ATCC 3502.

Heat-resistant spores of Clostridium botulinum can withstand the pasteurization processes in modern food processing. This poses a risk to food safety as spores may germinate into botulinum neurotoxin-producing vegetative cells. Sporulation in Bacillus subtilis, the model organism for sporulation, is regulated by the transcription factor Spo0A and four alternative sigma factors, SigF, SigE, SigG, and SigK. While the corresponding regulators are found in available genomes of C. botulinum, little is known about their expression. To accurately measure the expression of these genes using quantitative reverse-transcriptase PCR (RT-qPCR) during the exponential and stationary growth phases, a suitable normalization reference gene is required. 16S rrn, adK, alaS, era, gluD, gyrA, rpoC, and rpsJ were selected as the candidate reference genes. The most stable candidate reference gene was 16S ribosomal RNA gene (rrn), based on its low coefficient of variation (1.81%) measured during the 18-h study time. Using 16S rrn as the normalization reference gene, the relative expression levels of spo0A, sigF, sigE, sigG, and sigK were measured over 18h. The pattern of expression showed spo0A expression during the logarithmic growth phase, followed by a drop in expression upon entry to the stationary phase. Expression levels of sigF, sigE, and sigG peaked simultaneously at the end of the exponential growth phase. Peak expression of sigK occurred at 18h, however low levels of expression were detected during the exponential phase. These findings suggest these sigma factors play a role in C. botulinum sporulation that is similar, but not equal, to their role in the B. subtilis model.

Psychometric Validation of the Tactical Assessment Instrument in Football for Use in Physical Education and with Youth Sport Teams.

Recently, the Tactical Assessment Instrument in Football (TAIS) was developed to address football's tactical requirements in terms of game phases, learners' roles, and organizational levels of play. In this study, we sought to evaluate the psychometric properties of this existing instrument in the Physical Education (PE) context and for youth sport teams (ages 8-12 years). Our research design involved: (a) participants playing 37 football games, (b) assessing participants via observation with the TAIS and (c) conducting psychometric analysis on the obtained assessment data. For the psychometric analysis, we carried out our work in four phases: (a) a statistical analysis of the evaluation criteria, (b) analysis of the instrument's structural dimensions, (c) internal item reliability analysis, and (d) provision of evidence for external validity. Participants were 592 children (156 girls, 436 boys; ages 8-12 years) from 74 PE classes or sport teams (from three institutional contexts - schools, community-based sports, and sports clubs) in Spain. We selected 12 tactical criteria and grouped them into four theoretical dimensions (appropriate attack, inappropriate attack, appropriate defense, inappropriate defense) to confirm the instrument's structural dimensions. The Cronbach alpha and Omega McDonald coefficients were greater than .70. The TAIS discriminated between participants from the three institutional contexts, offering evidence of the instrument's external validity. Thus, the TAIS now has sufficient psychometric support for assessing learning of football tactics in PE and youth sport teams. This instrument facilitates an ecological assessment of youth players' understanding of football tactics through four theoretical tactical dimensions and 12 criteria involving information about four learners' roles (both attack and defense, on- and off-the-ball) and three organizational tactical levels of play (whole team, small groups of learners, and individual learners).

Crop cover and nutrient levels mediate the effects of land management type on aquatic invertebrate richness in prairie potholes.

Aquatic invertebrates provide important ecosystem services, including decomposition and nutrient cycling, and provide nutrition for birds, fish, amphibians, and bats. Thus, the effects of agricultural land management practices on aquatic invertebrates are relevant to farmers, wildlife biologists, and policymakers. Here, we used data on aquatic invertebrates (159 taxa, 73 to species, 75 to genus/family) collected in 40 wetlands in the Canadian prairies to test for direct and indirect relationships among land management types (perennial cover, organic, minimum tillage, conventional), landscape structure (cropland and wetland cover within the surrounding landscape), and water quality (total nutrient levels, turbidity) on species richness of invertebrates using structural equation modelling. Additionally, we assessed variation in community composition within and among wetlands in different land use management types using a direct gradient analysis and variance partitioning. The direct effects of land management type were not supported but we found strong supportive evidence that effects of land management on richness were significantly mediated through cropland cover, nutrient levels, and turbidity. After controlling for these indirect effects, aquatic invertebrate richness decreased along a gradient from the lowest to the highest farming intensity, i.e., richness decreased from perennial cover sites to organic to minimum tillage to conventional sites. Support was also found for negative effects of nutrient levels and turbidity on richness. We did not find significant support for differences in gamma diversity or a simple test (homogeneity of multivariate dispersions) of differences in turnover among land management types; however, land management had a significant effect in distance-based redundancy analysis. Taken together, these results suggest that focusing conservation efforts on reducing cropland erosion and nutrient inputs to wetlands and creating more permanent cover may be effective strategies for conserving richness of aquatic invertebrates in agricultural landscapes in this region.