Targeted Cattle Grazing to Enhance Sage-Grouse Brood-Rearing Habitat

Often, greater sage-grouse (Centrocercus urophasianus) brood-rearing habitats dominated by dense mountain big sagebrush (Artemisia tridentata vaseyana; >10-25% canopy cover) limit important forbs and arthropods sage-grouse rely on during summer. We investigated whether protein supplementation could concentrate cattle during fall to reduce sagebrush canopy cover and increase the diversity and abundance of forbs and arthropods. We applied targeted cattle grazing within three large, contiguous pastures in the Beaverhead Mountains of southwestern Montana. In each pasture, we selected one 4-ha macroplot of dense sagebrush (>30%). Within each macroplot, we placed low-moisture block protein supplement in four microsites (78.5-m2) and compared cattle response to four untreated control microsites. The following summer we measured herbaceous canopy cover and composition, shrub canopy cover, ground cover, forb and arthropod diversity, and arthropod density for each treated and untreated microsites. Mountain big sagebrush canopy cover was 71% less in treated vs. untreated microsites (11% vs. 38% canopy cover, respectively; P <0.001). Bite count observations indicated that sagebrush cover was reduced by cattle trampling rather than browsing, as sagebrush comprised <1% of cattle diets. Forb diversity was 13% greater in treated microsites (P = 0.094), forb species richness was 16% greater in treated microsites (P = 0.044), and forb composition trended higher in treated microsites (45% of herbaceous composition in treated microsites vs. 32% in untreated microsites; P = 0.106). Lepidoptera density trended 18% greater in treated microsites (P = .133). Our results indicate that protein supplementation during late fall can concentrate cattle to enhance sage-grouse brood-rearing habitat

Genome-Wide Association Study of Cardiac Structure and Systolic Function in African Americans: The Candidate Gene Association Resource (CARe) Study

Using data from four community-based cohorts of African Americans (AA), we tested the association between genome-wide markers (SNPs) and cardiac phenotypes in the Candidate-gene Association REsource (CARe) study

The genetic architecture of the human cerebral cortex

The cerebral cortex underlies our complex cognitive capabilities, yet little is known about the specific genetic loci that influence human cortical structure. To identify genetic variants that affect cortical structure, we conducted a genome-wide association meta-analysis of brain magnetic resonance imaging data from 51,665 individuals. We analyzed the surface area and average thickness of the whole cortex and 34 regions with known functional specializations. We identified 199 significant loci and found significant enrichment for loci influencing total surface area within regulatory elements that are active during prenatal cortical development, supporting the radial unit hypothesis. Loci that affect regional surface area cluster near genes in Wnt signaling pathways, which influence progenitor expansion and areal identity. Variation in cortical structure is genetically correlated with cognitive function, Parkinson's disease, insomnia, depression, neuroticism, and attention deficit hyperactivity disorder

New genetic loci link adipose and insulin biology to body fat distribution.

Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms

Causal effect of plasminogen activator inhibitor type 1 on coronary heart disease

Background--Plasminogen activator inhibitor type 1 (PAI-1) plays an essential role in the fibrinolysis system and thrombosis. Population studies have reported that blood PAI-1 levels are associated with increased risk of coronary heart disease (CHD). However, it is unclear whether the association reflects a causal influence of PAI-1 on CHD risk. Methods and Results--To evaluate the association between PAI-1 and CHD, we applied a 3-step strategy. First, we investigated the observational association between PAI-1 and CHD incidence using a systematic review based on a literature search for PAI-1 and CHD studies. Second, we explored the causal association between PAI-1 and CHD using a Mendelian randomization approach using summary statistics from large genome-wide association studies. Finally, we explored the causal effect of PAI-1 on cardiovascular risk factors including metabolic and subclinical atherosclerosis measures. In the systematic meta-analysis, the highest quantile of blood PAI-1 level was associated with higher CHD risk comparing with the lowest quantile (odds ratio=2.17; 95% CI: 1.53, 3.07) in an age- and sex-adjusted model. The effect size was reduced in studies using a multivariable-adjusted model (odds ratio=1.46; 95% CI: 1.13, 1.88). The Mendelian randomization analyses suggested a causal effect of increased PAI-1 level on CHD risk (odds ratio=1.22 per unit increase of log-transformed PAI-1; 95% CI: 1.01, 1.47). In addition, we also detected a causal effect of PAI-1 on elevating blood glucose and high-density lipoprotein cholesterol. Conclusions--Our study indicates a causal effect of elevated PAI-1 level on CHD risk, which may be mediated by glucose dysfunction

The genetic architecture of the human cerebral cortex

The cerebral cortex underlies our complex cognitive capabilities, yet little is known about the specific genetic loci that influence human cortical structure. To identify genetic variants that affect cortical structure, we conducted a genome-wide association meta-analysis of brain magnetic resonance imaging data from 51,665 individuals. We analyzed the surface area and average thickness of the whole cortex and 34 regions with known functional specializations. We identified 199 significant loci and found significant enrichment for loci influencing total surface area within regulatory elements that are active during prenatal cortical development, supporting the radial unit hypothesis. Loci that affect regional surface area cluster near genes in Wnt signaling pathways, which influence progenitor expansion and areal identity. Variation in cortical structure is genetically correlated with cognitive function, Parkinson's disease, insomnia, depression, neuroticism, and attention deficit hyperactivity disorder

Cerebellar Volume and Disease Staging in Parkinson's Disease: An ENIGMA-PD Study.

peer reviewed[en] BACKGROUND: Increasing evidence points to a pathophysiological role for the cerebellum in Parkinson's disease (PD). However, regional cerebellar changes associated with motor and non-motor functioning remain to be elucidated. OBJECTIVE: To quantify cross-sectional regional cerebellar lobule volumes using three dimensional T1-weighted anatomical brain magnetic resonance imaging from the global ENIGMA-PD working group. METHODS: Cerebellar parcellation was performed using a deep learning-based approach from 2487 people with PD and 1212 age and sex-matched controls across 22 sites. Linear mixed effects models compared total and regional cerebellar volume in people with PD at each Hoehn and Yahr (HY) disease stage, to an age- and sex- matched control group. Associations with motor symptom severity and Montreal Cognitive Assessment scores were investigated. RESULTS: Overall, people with PD had a regionally smaller posterior lobe (dmax  = -0.15). HY stage-specific analyses revealed a larger anterior lobule V bilaterally (dmax  = 0.28) in people with PD in HY stage 1 compared to controls. In contrast, smaller bilateral lobule VII volume in the posterior lobe was observed in HY stages 3, 4, and 5 (dmax  = -0.76), which was incrementally lower with higher disease stage. Within PD, cognitively impaired individuals had lower total cerebellar volume compared to cognitively normal individuals (d = -0.17). CONCLUSIONS: We provide evidence of a dissociation between anterior "motor" lobe and posterior "non-motor" lobe cerebellar regions in PD. Whereas less severe stages of the disease are associated with larger motor lobe regions, more severe stages of the disease are marked by smaller non-motor regions

Defoliation Timing Effects on Spotted Knapweed Seed Production and Viability

Spotted knapweed (Centaurea stoebe L.), a perennial invasive forb that reproduces largely by seed, often forms new flowers after prescribed sheep grazing or mowing is applied during the bolting or flowering stage. It is unknown if these new flowers produce viable seeds by the end of the growing season. The purpose of this 2-yr study was to determine the appropriate timing (or timings) or combination (or combinations) of timings of defoliation on spotted knapweed to reduce its viable seed production. Spotted knapweed plants on foothill rangeland in west-central Montana were hand-clipped at seven different timings and frequencies of defoliation: June (bolting stage); July (late-bud-early flowering stage); August (full-flowering stage); June + July; June + August; July + August; or June + July + August. Unclipped plants were controls. Plants clipped in the bolting stage were defoliated at 35-40% relative utilization. Plants clipped at all other timings had 100% of their buds and flowers removed, plus 3 cm of each bud or flower stem. Plant response was evaluated from mid-August through September, whenever the seed heads of each treatment’s plants reached maturity but while their seed-head bracts remained tightly closed. Clipping at any timing or combination of timings reduced the number of buds and flower heads per plant (P < 0.01), number of seeds per plant (P < 0.01), percentage of viability of seeds (P < 0.01), and number of viable seeds per plant (P < 0.01) compared with no clipping. Clipping during the bolting stage reduced the number of viable seeds by nearly 90% compared with no clipping. Clipping during the late-bud-early-flower or full-flower stage reduced the number of viable seeds by nearly 100% compared with no clipping. Spotted knapweed defoliation via prescribed sheep grazing or mowing in summer should suppress viable seed production of spotted knapweed. The Rangeland Ecology & Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202

Spotted Knapweed Utilization by Sequential Cattle and Sheep Grazing

Prescribed (or targeted) sheep grazing can effectively suppress the invasive perennial forb spotted knapweed (Centaurea stoebe L. ssp. micranthos [Gugler] Hayek). Some ranchers and other natural resource managers, however, resist using this weed management tool over concerns that sheep may consume too much of the graminoid standing crop, thereby decreasing its availability to cattle and wildlife and possibly harming graminoids with excessive defoliation. One potential approach to address these concerns is to graze spotted knapweed infestations first with cattle, immediately followed by sheep. We evaluated this sequential grazing strategy on foothill rangeland in western Montana, comparing sequential grazing at a moderate stocking rate in mid June (spotted knapweed in bolting stage) vs. mid July (spotted knapweed in late-bud/early flowering stage). Pastures (0.81 ha) were grazed with three yearling cattle for 7 d, immediately followed with 7 d of grazing by seven yearling sheep. Combined relative (i.e., utilization) of graminoids by cattle and sheep averaged 40% in June and July, safely within sustainable grazing use levels recommended for the site. Combined relative use of spotted knapweed by cattle and sheep also did not differ between June and July, averaging 62%. Previous research indicates that this degree of use is sufficient to suppress spotted knapweed. Our results indicate that prescribed sheep grazing can be applied immediately following cattle grazing in either June or July to suppress spotted knapweed without overusing desirable graminoids. Cattle and sheep will eat less graminoids and more spotted knapweed if cattle and sheep graze sequentially when spotted knapweed is in its late-bud/early flowering stage (mid July) rather than its bolting stage (mid June)./El pastoreo prescrito con ovejas puede suprimir de manera efectiva la herbácea perene invasiva spotted knapweed (Centaurea stoebe L. ssp. Micranthos [Gugler] Hayek). Sin embargo, algunos ganaderos y manejadores de recursos naturales, se resisten a utilizar esta herramienta de manejo por la preocupación de que las ovejas puedan consumir grandes cantidades de gramíneas, resultando en disminución y disponibilidad para el ganado y fauna silvestre. Asimismo, se teme que el consumo ocasione un daño a las gramíneas por una utilización intensiva. Un posible enfoque para hacer frente a estas preocupaciones es pastorear las áreas infestadas de spotted knapweed primero con ganado vacuno e inmediatamente después con ovejas. Evaluamos esta estrategia de pastoreo secuencial en los pastizales al pie de los lomeríos en el oeste de Montana, comparando el pastoreo secuencial con una densidad animal moderada a mediados de junio (etapa previa a la floración) en comparación con el pastoreo durante mediados de Julio (finales de la brotación/ principios de la e ́poca de floración). Parcelas de (0.86 has) fueron pastoreadas con tres vacas de un año por 7 días, inmediatamente fueron pastoreadas por 7 días con siete ovejas de un año. Combinando la utilización relativa de gramíneas por ganado y ovejas promediaron 40% in Junio y Julio, con seguridad estos niveles de pastoreo son sostenibles recomendados para este sitio. La relativa combinación de la utilización de spotted knapweed por ganado y ovejas tampoco produjo diferencias entre Junio y Julio, promediando 62%. Investigaciones previas indican que este grado de utilización es suficiente para suprimir spotted knapweed. Nuestros resultados indican que el pastoreo prescrito con ovejas puede ser implementado inmediatamente después del pastoreo con ganado vacuno ya sea en Junio o Julio para suprimir spotted knapweed sin la sobrevso de las gramíneas deseables. El ganado vacuno y las ovejas van a consumir menos gramíneas y mas spotted knapweed si ambos pastorean secuencialmente cuando spotted knapweed está en finales de la brotación/ principios de la e ́poca de floración (mediados de julio) en lugar de la etapa de floración (mediados de Junio).The Rangeland Ecology & Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202

Elk, Mule Deer, and Cattle Foraging Relationships on Foothill and Mountain Rangeland

Foraging niche overlap among Rocky Mountain elk (Cervus elaphus nelsoni), Rocky Mountain mule deer (Odocoileus hemionus hemionus), and cattle (Bos taurus) was studied for 2 years on 37 000 ha of nonforested foothill and mountain habitat in northwestern Wyoming. Microhistological analysis was used to quantify botanical composition of ungulate diets from monthly fecal collections. Feeding habitat use was determined through monthly surveys from fixed-wing aircraft to record nonsolitary animals in nonforested habitat. Kulcyznski’s similarity index was used to calculate dietary and feeding habitat overlap among the 3 ungulates, and these 2 indices were multiplied together to estimate foraging niche overlap. In all seasons, elk and cattle consumed grass-dominated diets (mean = 61% and 81%, respectively), although elk diets were more diverse. Mule deer consumed more forbs and shrubs than either elk or cattle (P < 0.10). Foraging niche overlap was high (45%) between mule deer and elk in spring. Cattle in summer and fall had 60% foraging niche overlap with elk in spring, indicating that, in spring, elk foraged in many of the same places (largely sagebrush grassland) and ate diets similar in botanical composition to what cattle did during summer and fall (principally Festuca idahoensis, Pseudoroegneria spicata, and Achnatherum spp.). Foraging niche overlap also was high (41%-51%) between elk in winter and cattle in summer and fall. Therefore, if competitive or complementary relationships existed between elk and cattle, these interactions most likely occurred on sagebrush grasslands where cattle use in summer-fall was followed by elk use in winter-spring. We recommend that resource managers focus their forage utilization and range trend monitoring in foothill sagebrush grasslands. The Rangeland Ecology & Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 2020Legacy DOIs that must be preserved: 10.2458/azu_jrm_v59i1_torstenso