3,911 research outputs found
Nondestructive testing of railroad wheels and rails by ultrasonics
Quality control of wheels and rails can be improved by using ultrasonic technique developed for measuring stresses in metallic materials. In addition, parts already in use can be tested and replaced if they are found to be unsafe. Test equipment includes two transducers
Association of smoking and nicotine dependence with pre-diabetes in young and healthy adults.
INTRODUCTION: Several studies have shown an increased risk of type 2 diabetes among smokers. Therefore, the aim of this analysis was to assess the relationship between smoking, cumulative smoking exposure and nicotine dependence with pre-diabetes.
METHODS: We performed a cross-sectional analysis of healthy adults aged 25-41 in the Principality of Liechtenstein. Individuals with known diabetes, Body Mass Index (BMI) >35 kg/m² and prevalent cardiovascular disease were excluded. Smoking behaviour was assessed by self-report. Pre-diabetes was defined as glycosylated haemoglobin between 5.7% and 6.4%. Multivariable logistic regression models were done.
RESULTS: Of the 2142 participants (median age 37 years), 499 (23.3%) had pre-diabetes. There were 1,168 (55%) never smokers, 503 (23%) past smokers and 471 (22%) current smokers, with a prevalence of pre-diabetes of 21.2%, 20.9% and 31.2%, respectively (p <0.0001). In multivariable regression models, current smokers had an odds ratio (OR) of pre-diabetes of 1.82 (95% confidential interval (CI) 1.39; 2.38, p <0.0001). Individuals with a smoking exposure of <5, 5-10 and >10 pack-years had an OR (95% CI) for pre-diabetes of 1.34 (0.90; 2.00), 1.80 (1.07; 3.01) and 2.51 (1.80; 3.59) (p linear trend <0.0001) compared with never smokers. A Fagerström score of 2, 3-5 and >5 among current smokers was associated with an OR (95% CI) for pre-diabetes of 1.27 (0.89; 1.82), 2.15 (1.48; 3.13) and 3.35 (1.73; 6.48) (p linear trend <0.0001).
DISCUSSION: Smoking is strongly associated with pre-diabetes in young adults with a low burden of smoking exposure. Nicotine dependence could be a potential mechanism of this relationship
Net N mineralization in subalpine grasslands: effect of aboveground vertebrate and invertebrate herbivores
Aboveground herbivores have strong effects on grassland nitrogen (N) cycling. They can accelerate or slow down soil net N mineralization depending on ecosystem productivity and grazing intensity. We assessed how a diverse herbivore community affects net N mineralization in subalpine grasslands. By using size-selective fences, we progressively excluded large, medium, and small mammals, as well as invertebrates from two vegetation types, and assessed how the exclosure types (ET) affected net N mineralization. The two vegetation types differed in long-term management (centuries), forage quality, and grazing history and intensity. To gain a more mechanistic understanding of how herbivores affect net N mineralization, we linked mineralization to soil abiotic (temperature; moisture; NO3, NH4, and total inorganic N concentrations/pools; C, N, P concentrations; pH; bulk density), soil biotic (microbial biomass; abundance of collembolans, mites, and nematodes) and plant (shoot and root biomass; consumption; plant C, N, and fiber content; plant N pool) properties.
Net N mineralization differed between ET, but not between vegetation types. Thus, shortterm changes in herbivore community composition and, therefore, in grazing intensity had a stronger effect on net N mineralization than long-term management and grazing history. We found highest N mineralization values when only invertebrates were present, suggesting that mammals had a negative effect on net N mineralization. Of the variables included in our analyses, only mite abundance and aboveground plant biomass explained variation in net N mineralization among ET. Abundances of both mites and leaf-sucking invertebrates were positively correlated with aboveground plant biomass, and biomass increased with progressive exclusion. The negative impact of mammals on net N mineralization may be related partially to (1) differences in the amount of plant material (litter) returned to the belowground subsystem, which induced a positive bottom-up effect on mite abundance, and (2) alterations in the amount and/or distribution of dung, urine, and food waste. Thus, our results clearly show that short-term alterations of the aboveground herbivore community, can strongly impact nutrient cycling within ecosystems independent of long-term management and grazing history
Perch-type Characteristics of Overwintering Red-tailed Hawks (Buteo jamaicensis) and American Kestrels (Falco sparverius)
Red-tailed Hawks (Buteo jamaicensis) and American Kestrels (Falco sparverius) are primarily sitand-wait predators that rely on perches to forage most efficiently. Overwintering Red-tailed Hawks and American Kestrels use available perches (e.g., utility poles and wires, trees, fences, gates, etc.) to hunt for prey items in agricultural fields in northeast Arkansas. Observations were made from December 2011-March 2012 and November 2012-March 2013 in three representative cover-types (short rice stubble, soybean stubble, and fallow areas including roadsides) to determine which perch-types were used by Red-tailed Hawks and American Kestrels. Utility pole crossbeams at an average height of 6.3 m were the main perchtypes used by Red-tailed Hawks, demonstrating the use of man-made structures’. These perches were generally in or near fallow areas or short rice stubble fields. Conversely, American Kestrels usually perched on wires at an average height of 4.9 m, over fallow roadsides’. Fallow areas had high prey density and vegetation cover. Niche separation via differential use of perches may be one factor that allows these raptors to avoid inter-specific competition
Exploratory topic modeling with distributional semantics
As we continue to collect and store textual data in a multitude of domains,
we are regularly confronted with material whose largely unknown thematic
structure we want to uncover. With unsupervised, exploratory analysis, no prior
knowledge about the content is required and highly open-ended tasks can be
supported. In the past few years, probabilistic topic modeling has emerged as a
popular approach to this problem. Nevertheless, the representation of the
latent topics as aggregations of semi-coherent terms limits their
interpretability and level of detail.
This paper presents an alternative approach to topic modeling that maps
topics as a network for exploration, based on distributional semantics using
learned word vectors. From the granular level of terms and their semantic
similarity relations global topic structures emerge as clustered regions and
gradients of concepts. Moreover, the paper discusses the visual interactive
representation of the topic map, which plays an important role in supporting
its exploration.Comment: Conference: The Fourteenth International Symposium on Intelligent
Data Analysis (IDA 2015
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The impact of adjusting for baseline in pharmacogenomic genome-wide association studies of quantitative change.
In pharmacogenomic studies of quantitative change, any association between genetic variants and the pretreatment (baseline) measurement can bias the estimate of effect between those variants and drug response. A putative solution is to adjust for baseline. We conducted a series of genome-wide association studies (GWASs) for low-density lipoprotein cholesterol (LDL-C) response to statin therapy in 34,874 participants of the Genetic Epidemiology Research on Adult Health and Aging (GERA) cohort as a case study to investigate the impact of baseline adjustment on results generated from pharmacogenomic studies of quantitative change. Across phenotypes of statin-induced LDL-C change, baseline adjustment identified variants from six loci meeting genome-wide significance (SORT/CELSR2/PSRC1, LPA, SLCO1B1, APOE, APOB, and SMARCA4/LDLR). In contrast, baseline-unadjusted analyses yielded variants from three loci meeting the criteria for genome-wide significance (LPA, APOE, and SLCO1B1). A genome-wide heterogeneity test of baseline versus statin on-treatment LDL-C levels was performed as the definitive test for the true effect of genetic variants on statin-induced LDL-C change. These findings were generally consistent with the models not adjusting for baseline signifying that genome-wide significant hits generated only from baseline-adjusted analyses (SORT/CELSR2/PSRC1, APOB, SMARCA4/LDLR) were likely biased. We then comprehensively reviewed published GWASs of drug-induced quantitative change and discovered that more than half (59%) inappropriately adjusted for baseline. Altogether, we demonstrate that (1) baseline adjustment introduces bias in pharmacogenomic studies of quantitative change and (2) this erroneous methodology is highly prevalent. We conclude that it is critical to avoid this common statistical approach in future pharmacogenomic studies of quantitative change
Amphibian, Reptile, and Small Mammal Associates of Ozark Pocket Gopher Habitat in Izard County, Arkansas
We conducted a study of the amphibian, reptile, and small mammal community assemblage of Ozark pocket gopher (Geomys bursarius ozarkensis) habitat in north-central Arkansas. We used 2 methods to capture individuals: hand capture and drift fences. During the study, we captured and marked a total of 9 anuran, 4 salamander, 5 lizard, 3 turtle, 16 snake, and 8 small mammal species exclusive of pocket gophers. We found one hatchling three-toed box turtle (Terrapene carolina triunguis) and one rough earth snake (Virginia striatula) inside a pocket gopher burrow and mound, respectively. Additionally, we witnessed both eastern racers (Coluber constrictor) and eastern coachwhips (Masticophis flagellum) retreat into pocket gopher burrows, as well as Hurter’s spadefoots (Scaphiopus holbrookii hurterii) burrow into pocket gopher mounds when released. Our results highlight the importance of mammalian burrows, specifically pocket gophers, to other vertebrate associates in grassland ecosystems. Both conservationists and managers need to determine the pocket gopher’s impact on ecosystem health and viability, specifically in natural grasslands, before conservation and/or management strategies are employed
Broad-spectrum Antibiotic Prophylaxis in Tumor and Infected Orthopedic Surgery - the prospective-randomized, microbiologist-blinded, stratified, superiority Trials - BAPTIST trials
Background: The perioperative antibiotic prophylaxis with 1st or 2nd-generation cephalosporins is evidence-based in orthopedic surgery. There are, however, situations with a high risk of prophylaxis-resistant surgical site infections (SSI).
Methods: We perform a superiority randomized-controlled trial with a 10% margin and a power of 90% in favor of the broad-spectrum prophylaxis. We will randomize orthopedic interventions with a high risk for SSI (open fractures, surgery under therapeutic antibiotics, tumor surgery, spine surgery with ASA-Score ≥ 3 points) in a prospective-alternating scheme (1:1, standard prophylaxis with mostly cefuroxime versus a broad-spectrum prophylaxis of a combined single-shot of vancomycin 1 g & gentamicin 5 mg/kg parenterally). The primary outcomes are "remission" at 6 weeks; or at 1 year for surgeries with implant. Secondary outcomes are the risk for prophylaxis-resistant SSI pathogens, revision surgery for any reason, change of antibiotic therapy, adverse events and the incidence of non-SSI infections within 6 weeks (e.g. urine infections). With event-free surgeries to 95% in the broad-spectrum versus 85% in the standard arm, we need 2 x 207 orthopedic surgeries among all groups.
Discussion: In selected patients with a high risk for prophylaxis-resistant SSI, a broad-spectrum combination might prevent SSIs better than the standard prophylaxis.
Trial registration: ClinicalTrial.gov NCT05502380. Registered on 12 August 2022.
Protocol version: 2 (3 June 2022
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