233 research outputs found

    First Documented Pathologies in Tenontosaurus tilletti with Comments on Infection in Non-Avian Dinosaurs

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    In 2001, a nearly complete sub-adult Tenontosaurus tilletti was collected from the Antlers Formation (Aptian-Albian) of southeastern Oklahoma. Beyond its exceptional preservation, computed tomography (CT) and physical examination revealed this specimen has five pathological elements with four of the pathologies a result of trauma. Left pedal phalanx I-1 and left dorsal rib 10 are both fractured with extensive callus formation in the later stages of healing. Left dorsal rib 7 (L7) and right dorsal rib 10 (R10) exhibit impacted fractures compressed 26 mm and 24 mm, respectively. The fracture morphologies in L7 and R10 indicate this animal suffered a strong compressive force coincident with the long axis of the ribs. All three rib pathologies and the pathological left phalanx I-1 are consistent with injuries sustained in a fall. However, it is clear from the healing exhibited by these fractures that this individual survived the fall. In addition to traumatic fractures, left dorsal rib 10 and possibly left phalanx I-1 have a morphology consistent with post-traumatic infection in the form of osteomyelitis. The CT scans of left metacarpal IV revealed the presence of an abscess within the medullary cavity consistent with a subacute form of hematogenous osteomyelitis termed a Brodie abscess. This is only the second reported Brodie abscess in non-avian dinosaurs and the first documented occurrence in herbivorous dinosaurs. The presence of a Brodie abscess, known only in mammalian pathological literature, suggest mammalian descriptors for bone infection may be applicable to non-avian dinosaurs.We thank R. Cifelli, S. Westrop, and N. Czaplewski for reviewing early drafts of this manuscript. This research was funded by grants awarded to R. L. Cifelli by the American Chemical Society, Petroleum Research Fund (ACS-PRF#38572-AC8) and the National Science Foundation (DEB 9870173). Open Access Fees paid for whole or in part by the University of Oklahoma Libraries Open Initiatives.Ye

    S. cerevisiae Srs2 helicase ensures normal recombination intermediate metabolism during meiosis and prevents accumulation of Rad51 aggregates

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    YesWe investigated the meiotic role of Srs2, a multi-functional DNA helicase/translocase that destabilises Rad51-DNA filaments and is thought to regulate strand invasion and prevent hyper-recombination during the mitotic cell cycle. We find that Srs2 activity is required for normal meiotic progression and spore viability. A significant fraction of srs2 mutant cells progress through both meiotic divisions without separating the bulk of their chromatin, although in such cells sister centromeres often separate. Undivided nuclei contain aggregates of Rad51 colocalised with the ssDNA-binding protein RPA, suggesting the presence of persistent single-strand DNA. Rad51 aggregate formation requires Spo11-induced DSBs, Rad51 strand-invasion activity and progression past the pachytene stage of meiosis, but not the DSB end-resection or the bias towards interhomologue strand invasion characteristic of normal meiosis. srs2 mutants also display altered meiotic recombination intermediate metabolism, revealed by defects in the formation of stable joint molecules. We suggest that Srs2, by limiting Rad51 accumulation on DNA, prevents the formation of aberrant recombination intermediates that otherwise would persist and interfere with normal chromosome segregation and nuclear division.Biotechnology and Biological Sciences Research Council (BB/K009346/1

    Sixty Years of Fractal Projections

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    Sixty years ago, John Marstrand published a paper which, among other things, relates the Hausdorff dimension of a plane set to the dimensions of its orthogonal projections onto lines. For many years, the paper attracted very little attention. However, over the past 30 years, Marstrand's projection theorems have become the prototype for many results in fractal geometry with numerous variants and applications and they continue to motivate leading research.Comment: Submitted to proceedings of Fractals and Stochastics

    Current knowledge on the environmental fate, potential impact, and management of growth-promoting steroids used in the US beef cattle industry

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    Growth promoting steroids and steroid-like compounds (GPSC) used by the US beef cattle industry are potential contaminants to water resources. Manure generated in concentrated animal feeding operations contains GPSCs that may enter the environment. Several studies have focused on off-site impacts of GPSC in aquatic life and suggest possible adverse impacts such as abnormal blood hormone levels, masculinization of females, feminization of males, altered sex ratios, intersexuality and reduced fertility. Other studies point to potential human health impacts including increased incidence of human cancers, sexual disorders, and decline in male: female ratio in human beings. However, the use of GPSCs in beef production provides benefits to both cattle producers (less time and cost to raise cattle) and consumers (lower meat prices) and to some extent on the environment. This review discusses major scientific findings and issues related to the use of GPSCs by the cattle industry, their environmental impacts, existing knowledge gaps and potential strategies to manage GPSC movement in the environment. We found that although there have been many studies, there is no consensus on the extent of the problem, and the effects in the environment. Current environmental regulations could be adapted to include GPSCs if necessary

    Transport of steroid hormones in the vadose zone after land application of beef cattle manure

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    A variety of naturally occurring steroid hormones are regularly excreted by livestock, while additional steroid hormones have been used as growth promoters by the livestock industry. Depending on manure age and storage conditions, both groups of compounds are likely to be present during application to crops. Recent research suggests that some estrogens, androgens and progestagens in surface waters may originate from runoff after land application of livestock manure. Groundwater may also be impacted by livestock manure when used as a nutrient source to crops and may be indicated by excess nitrate in water. Few studies have been conducted to investigate the potential of steroid hormones contamination of groundwater. The objective of this study was to monitor leaching of steroid hormones and other compounds associated with livestock manure through the soil profile after land application of manure. The study was conducted near North Platte, Nebraska between April 2008 and July 2011 on a silt loam soil. Leachate was collected at the bottom of 2.4 meter deep monolithic percolation lysimeters to sample water leached beneath plots fertilized with manure. Soil samples were also collected from surrounding irrigated field plots. Treatments consisted of two manure handling procedures (stockpiling and composting) and a check receiving no manure application. Manure stored from a previous year’s cattle feeding pen study was sampled and analyzed for steroid hormone content. Manure was applied to the lysimeters and adjacent plot areas in April 2008 at a rate satisfying the nitrogen requirements of winter wheat planted in the fall of 2007 and 2008 followed by soybeans planted in the spring of 2010 and 2011. Leachate from the lysimeters and soil samples (down to 2.4 meter depth) from surrounding areas were collected periodically during the study. Laboratory analyses of manure, soil, and leachate samples used liquid chromatography tandem mass spectrometry to identify 17 steroid hormones and metabolites. Progesterone, estrone, beta-zearalenol and 4-androstenedione were detected at varying concentrations in both composted (1.6-8.4 nanograms per gram) and stockpiled (3.7-11.4 nanograms per gram) manure. Steroid hormones and related compounds were detected in only 5 percent of the leachate samples. The greatest detected concentration was 20 nanograms per liter of natural progesterone in a leachate sample from a lysimeter treated with stockpiled manure. Steroid hormones or metabolites were detected in 10 percent of the soil samples. Seventy four percent of the detections in the soil samples were in the top half (top 1.2 meter) of the sampled soil depth. 17beta-estradiol was detected the most in the soil samples (4 percent) with a maximum concentration of 4.3 nanograms per gram in a plot treated with composted manure. No synthetic steroids were detected in any of the soil or leachate samples. The low detection of steroid hormones in the soil and leachate samples suggests that, while some hormones may move through the soil, most are readily degraded or adsorbed after manure application. Additional research is required to more clearly identify the mechanisms that control the environmental fate and transport of steroid hormones through the soil

    Influence of soil properties and test conditions on sorption and desorption of testosterone

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    In this study, batch sorption and desorption experiments were conducted for testosterone using four agricultural soils and five clay minerals. Significant differences in sorption behavior were observed between abiotic and biotic systems. The Freundlich sorption coefficient Kf (µg per g)/(µg per mL) ranged from 8.53 to 74.46 for soils and from 35.28 to 1243 for clays. The maximum sorption capacity (µg per g) of soils ranged from 25.25 to 440.61 for soils and 168.46 to 499.84 for clays. Correlation of sorption model parameters with soil properties indicated that both clay content and soil organic matter are important variables in predicting testosterone sorption behavior. Observed testosterone desorption from agricultural soils ranged from approximately 14 to 100 percent after 3 desorption cycles, and the desorption percentage decreased as the initial testosterone concentration decreased. Temperature, ionic strength, the water/soil ratio and soil depth were determined to influence sorption and desorption of testosterone. Desorption significantly increase with the soil depth and with the increase in the water to soil ratio. Temperature had an inverse effect on the sorption capacity of the soils tested. Thermodynamic calculations showed that the enthalpy change of the soils tested were the range of 12.9-20.7 kJ per mol, indicating weak interaction between testosterone and soil. Our results suggest that additional studies on how soil particles with different size fractions affect hormones fate and transport are needed in order to determine the potential risk of testosterone leaching or runoff

    Effect of rainfall timing and tillage on the transport of steroid hormones in runoff from manure amended row crop fields

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    Manure generated from concentrated animal feeding operations (CAFOs) represents one of the major sources of steroid hormones found in surface water. This paper presents results of a study conducted near Concord, NE to determine the effects of manure handling (compost vs. stockpile), tillage (no-till, plow plus disk and disk), and rainfall timing (24 h and 30 d after manure application (DAT)) on the transport of steroids from row crop fields via surface runoff. Manure was collected following a feedlot study where one set of female cattle were administered growth promoting steroids and mycotoxins and one set received no treatments. Manure was either stockpiled for 9 months or composted prior to application. Twelve of 17 steroids or their metabolites were identified in the manure that was applied at agronomic rates to cropland in a no-till production system for more than 5 years. Chemical analysis of runoff samples detected steroids in less than 50% of the runoff samples and less than 10% of the samples contained more than one individual steroid or mycotoxin. The median concentration of androgens, and progestagens in surface runoff samples decreased by more than 50% between the 1 DAT to 30 DAT sampling dates. The percentage of detections increased between 24-h and 30-d after manure application largely due to increased levels of mycotoxins produced by the Fusarium genus of fungi common to corn fields. In addition, the physical and chemical properties of the steroids result appear to contribute to their long term degradation once applied to the soil. Based on this study, the combination of stockpiling manure prior to application and incorporation into the soil would likely result in the least potential for steroid transport to surface waters

    Effect of composting on the fate of steroids in beef cattle manure

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    In this study, the fate of steroid hormones in beef cattle manure composting is evaluated. The fate of 16 steroids and metabolites was evaluated in composted manure from beef cattle administered growth promotants and from beef cattle with no steroid hormone implants. The fate of estrogens (primary detected as estrone), androgens, progesterone, and the fusarium metabolite and implant a-zearalanol were monitored in manure compost piles. First-order decay rates were calculated for steroid half-lives in compost and ranged from 8 days for androsterone to 69 days for 4-androsterone. Other steroid concentration data did not fit first-order decay models which may indicate that other microbial processes may result in steroid production or synthesis in composting systems. We demonstrate that composting is an effective strategy to remove steroid hormones from manure. Total steroid hormone removal in composted beef cattle manure ranged from 79-87%

    Influence of innovation capability and customer experience on reputation and loyalty

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    This research employs complexity theory to understand the effect of innovation capability and customer experience on reputation and loyalty. In addition, it aims to investigate the contribution of consumer demographics to such relationships. To this end, this paper recognizes effective and intellectual experiences as key elements of customer experience to propose a conceptual framework with research propositions. To examine the research propositions, this study used confirmatory factor analysis (CFA) and fuzzy set qualitative comparative analysis (fsQCA) using a sample of 606 consumers of international retail brands. The findings contribute to academic literature on innovation, customer and brand management. It also provides guidelines for managers to create customer value by deploying technical innovation capability (new services, service operations and technology) and non-technical innovation capability (management, sales, and marketing) together in a retail environment. Furthermore, it reflects on the linkage between the consumer shopping experience and firm reputation and loyalty

    Use of a surrogate to evaluate the impact of tillage on the transport of steroid hormones from manure-amended agricultural field

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    Beef feedlot manure distributed to row crop production areas is a potential surface water contaminant source of the steroid hormones commonly used in beef cattle production. This article reports on research conducted at the University of Nebraska Haskell Agricultural Laboratory near Concord, Nebraska, in July 2009. Manure, collected from beef feedlot pens, was stockpiled for ten months prior to application to a row crop field. Previous research identified that the detection frequency of steroid hormones in beef manure varies greatly. Thus, a surrogate (17 alpha-ethynylestradiol, EE2) was applied at a rate of 75 g per ha to ensure detectable concentrations in surface runoff samples. EE2 was applied directly to beef cattle manure and to bare soil. The EE2 and manure were either incorporated using a single disk treatment (T) or left on the soil surface in a no-till practice (NT). A rainfall simulation experiment was conducted 24 h after manure and EE2 incorporation using a factorial design consisting of tillage, manure, and EE2 treatments. Runoff samples were collected at 5 min intervals during a 30 min runoff period for each plot. Results indicated 96 percent less EE2 mass transport from disk tilled plots compared to no-till. The greatest loss of EE2 was 156 and 6 mg per ha from no-till and disked plots, respectively. Results of this study showed that a single-pass disk tillage treatment can limit the overland transport of steroid hormones from crop production areas
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