117,706 research outputs found
Invited review: β-hydroxybutyrate concentration in blood and milk and its associations with cow performance
No full textHyperketonemia (HYK) is one of the most frequent and costly metabolic disorders in high-producing dairy cows and its diagnosis is based on β-hydroxybutyrate (BHB) concentration in blood. In the last 10 years, the number of papers that have dealt with the impact of elevated BHB levels in dairy cattle has increased. Therefore, this paper reviewed the recent literature on BHB concentration in blood and milk, and its relationships with dairy cow health and performance, and farm profitability. Most studies applied the threshold of 1.2 mmol/l of BHB concentration in blood to indicate HYK; several authors considered BHB concentrations between 1.2 and 2.9 mmol/l as subclinical ketosis, and values ⩾ 3.0 mmol/l as clinical ketosis. Results on HYK frequency (prevalence and incidence) and cow performance varied according to parity and days in milk, being greater in multiparous than in primiparous cows, and in the first 2 weeks of lactation than in later stages. Hyperketonemia has been associated with greater milk fat content, fat-to-protein ratio and energy-corrected milk, and lower protein and urea nitrogen in milk. The relationships with milk yield and somatic cell count are still controversial. In general, HYK impairs health of dairy cows by increasing the risk of the onset of other early lactation diseases, and it negatively affects reproductive performance. The economic cost of HYK is mainly due to impaired reproductive performance and milk loss. From a genetic point of view, results from the literature suggested the feasibility of selecting cows with low susceptibility to HYK. The present review highlights that milk is the most promising matrix to identify HYK, because it is easy to sample and allows a complete screening of the herd through BHB concentration predicted using mid-IR spectroscopy during routine milk recording. Further research is needed to validate accurate and convenient methods to discriminate between cows in risk of HYK and healthy animals in field conditions and to support farmers to achieve an early detection and minimise the economic losses
Genetic and Nongenetic Variation of Blood Metabolites Predicted from Milk Infrared Spectra in Dairy Cattle
No full textThe negative energy balance experienced by dairy cows in early lactation caused by the lack of trade-off between energy intake (input) and requests for lactogenesis (output) is responsible for the occurrence of metabolic disorders. Blood metabolites are important indicators to monitor nutritional and energy status of the cows, and to detect the presence of metabolic disorders. In particular, the hyperketonemia (HYK) is one of the most frequent and costly metabolic diseases in early-lactation dairy cows, and it is commonly diagnosed through the determination of β-hydroxybutyrate (BHB) concentration in blood.
With this background, the overall objectives of the present thesis were: i) to summarise literature results on phenotypic and genetic aspects of BHB concentration in blood and milk of dairy cows; ii) to develop mid-infrared (MIR) spectroscopy prediction models for routine determination of blood metabolites; iii) to describe phenotypic variation of MIR-predicted blood metabolites in Brown Swiss, Holstein-Friesian and Simmental cattle breeds; iv) to assess the genetic variation of blood BHB and nonesterified fatty acids (NEFA) predicted by MIR spectroscopy, and their correlations with milk production and composition traits in early-lactation Italian Holstein dairy cows.
Hyperketonemia is an abnormal concentration of circulating ketone bodies in the blood; in particular, concentration of blood BHB ≥ 1.2 mmol/L is commonly recognized as indicator of HYK. In general, HYK impairs health of dairy cows by increasing the risk of the onset of other early-lactation diseases, and it negatively affects reproductive performance. Although the relationship with milk yield is still controversial, HYK has a detrimental effect on milk composition. Costs of HYK are mainly imputable to impaired fertility and milk loss. From a genetic point of view, results from the literature suggested the feasibility of selecting cows with low susceptibility to HYK. Milk is the most promising matrix to monitor HYK, taking advantage of using MIR spectroscopy during routine milk recording.
The effectiveness of using routine milk MIR spectra to predict main blood metabolites in early-lactation dairy cows was evaluated. Blood BHB, urea and NEFA were the most predictable traits. Predicted blood BHB showed an improved performance in detecting cows with HYK, compared with commercial calibration equation for milk BHB.
Factors associated with the phenotypic variation of MIR-predicted blood metabolites were investigated on a large spectral multi-breed database. Holstein-Friesian cows had the greatest concentration of blood BHB and NEFA, and the lowest blood urea content. Blood BHB and NEFA concentrations generally increased with parity. The greatest BHB concentration was observed in the first 10 days of lactation, except for Simmental cows. From 5 to 35 days in milk, NEFA concentration decreased, whereas urea content increased for all considered breeds. The maximum levels of blood BHB and NEFA concentrations were recorded in spring and early summer. Blood urea generally increased across the year, from spring to winter.
Genetic parameters for MIR-predicted blood BHB and NEFA concentrations were estimated. The greatest heritability for both metabolites was assessed in the first 10 days after calving (0.32 for BHB and 0.23 for NEFA), and their genetic correlation varied from 0.50 to 0.60. Moreover, an unfavourable trend of estimated breeding values for both blood BHB and NEFA concentrations across year of birth of the bulls was detected. Genetic correlations of BHB and NEFA with milk yield, somatic cell score, protein, lactose and urea content were similar or at least in the same direction, whereas opposite correlations were observed with fat content and fat-to-protein ratio
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Process controlling beach nourishment performance at Delray Beach, Florida, USA
No full textBeach erosion is a chronic problem in the southeast coast of the State of Florida, where Delray Beach is located. To mitigate increasing erosion problems (subsequent) beach nourishment projects were constructed along the entire sandy coast of the state of Florida. At Delray Beach, the beach was nourished 7 times since 1973 using approximately 5.7 million m3 of sediments along a stretch of beach of about 4km. Sand for these beach nourishment projects was extracted from an area immediately offshore of the project site, from blanket deposits that overlay bedrock and are located just landward of offshore coral reefs.Critical evaluation of sediment data for several years was initially conducted to investigate the hypothesis raised by previous authors that higher erosion in the south end of the project is due to the occurrence of finer beach sand at this segment. Data from multiple annual monitoring reports demonstrated that alongshore grain size distribution on Delray Beach varies significantly, temporally and spatially, and that there is no persistent trend of finer grain sizes being located in the erosional hot spot segment compared to the rest of the beach; in fact, grain size differences within the project area can be considered to be minor. This data provided enough evidence to conclude that grain size differences alongshore were not the cause of increased hot sport erosion.Wave modelling and morphological modelling also suggested that the gaps in the offshore shore parallel reef system were not responsible for hot spot erosion. The effects of the barrier reefs on the nearshore waves and currents were relatively minor as evidenced by numerical model results. Strong alongshore variability in wave height and associated pronounced areas wave shadowing and focusing zones were observed along the project area in initial numerical modelling efforts, but these were attributed to wave transformation over the dredge pits located offshore of the nourished beach. Near the erosion hot spot segment on the south end of the project, however, these variations in nearshore wave heights were relatively small compared to other segments of the project.Five methods of wave climate schematization designed to reduce a full wave time-series into a representative set of conditions for coastal morphological modeling were evaluated to achieve the first task. Of all the methods of wave climate schematization tested the ´Energy Flux Method´ and ´Opti Method´ showed best results in terms of representing accurately the sediment transport of the benchmark wave climate with a reduced set of wave conditions. The Energy Flux Method was identified as the preferred technique because it was relatively easy to apply, it is not subjective since waves are selected as a function of wave energy distribution and shows satisfactory performance even when compared to more complex and time intensive methodologies such as the Opti method.The research conducted in this thesis demonstrates that some engineering solutions such as the backfilling of all the dredge pits or introduction of permeable structures at the downdrift (south) end of the Delray Beach nourishment project can improve the performance of the nourishment reducing volumetric losses with mild downdrift effects. Since the downdrift beaches are receiving sediment lost from the nourishment project “free of costs”, a 50 per cent reduction of these losses implies that the downdrift beaches will still be receiving sediments, but half the amount. Each intervention will, however, impact updrift and downdrift beaches in a different way; have its costs and its environmental impacts, therefore, before further consideration for implementation of these significant project modifications a complete engineering, economic and environmental feasibility analysis is recommended
Square Dancing with the Stars to Enhance Dynamic Hirschman Linkages?
No full textIn this Presidential Address, the author takes the reader on a reconnaissance of his life and time as a regional scientist. He points out scenery he found scintillating along the way, hoping that some may pick up the banner and chew on a few of the ideas for a while. He suggests a revisit to Albert O. Hirschman’s notion of key sectors and more empirical analysis related to Marcus Berliant’s and Masahisa Fujita’s notion of knowledge creation and transfer.Presidential Address, San Antonio, Texas, March 29, 2014 (53rd Meetings of the Southern Regional Science Association
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
MgAlTi-LDH/gCN heterocomposites analyzed by x-ray photoelectron spectroscopy
No full textLayered double hydroxides (LDHs) and graphitic carbon nitride (gCN) are burgeoning multifunctional materials that have attracted a considerable interest as heterogeneous catalysts for environmental remediation. In the present work, we report on the x-ray photoelectron spectroscopy characterization of a representative MgAlTi-LDH/gCN heterocomposite, obtained by a simple mixing of single powdered constituents. Monochromated Al K-alpha radiation (1486.6 eV) was used as the source of x-ray excitation to acquire both wide-scan spectra and high-resolution signals of the principal element core levels. The main spectral features of the target system are critically examined and discussed in relation to the data related to the pristine MgAlTi-LDH. The obtained results highlight the occurrence of an electronic interplay between the single material constituents, anticipating an enhanced separation of photogenerated charge carriers and an improved activity for photocatalytic applications. The present reported data will serve as comparison for LDH-based materials obtained under various processing conditions for different end-uses
Letter from unknown writer to Jesse L. Boyce
No full textLetter to Jesse L. Boyce from unknown author (possibly Jack) about the investigation into the powder magazine located in the Grand Canyon. Some personal news is included in the letter such as the writer's marriage to the daughter of C.A. Taylor, former Supervisor of Cochise County
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Sarah L. Blum Author Visit - Warrior Nurse: PTSD and Healing
No full textHear Sarah L. Blum, author of Women Under Fire: Abuse in the Military, discuss her newest book, Warrior Nurse: PTSD and Healing followed by a Q&A and book signing.
Sarah L. Blum is a decorated Vietnam veteran who served as an operating room nurse during the intense fighting of 1967. In recognition of her service, she was awarded the Army Commendation Medal.
Sponsored by CWU Veterans Center and CWU Libraries.https://digitalcommons.cwu.edu/libraryevents/1252/thumbnail.jp
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