Effects of parity and early pregnancy on peripheral blood leukocytes in dairy cattle.

Subfertility remains a major problem in the dairy industry. Only 35-40% of high-yielding dairy cows and 55-65% of nonlactating heifers become pregnant after their first service. The immune system plays a critical role in the establishment of pregnancy. However, it can also create challenges for embryo survival and contribute to reduced fertility. We conducted 2 separate experiments to characterize changes in subsets of peripheral blood leukocytes (PBL) and their phenotype over the estrous cycle and early pregnancy in heifers and cows. We used flow cytometry and RT-qPCR to assess protein and mRNA expression of molecules important for immune function. We observed that monocytes and T cells were most affected by pregnancy status in heifers, whereas, CD8+ lymphocytes and natural killer (NK) cells were most affected during early pregnancy in cows. Changes in immune parameters measured appeared to be greater in heifers than cows including changes in expression of numerous immune function molecules. To test the hypothesis, we conducted a third experiment to simultaneously analyze the immunological responses to pregnancy between cows and heifers. We observed that cows had greater expression of proinflammatory cytokines and molecules associated with leukocyte migration and phagocytosis compared to heifers. Moreover, animals that failed to become pregnant showed altered expression of anti-inflammatory molecules. Overall, these findings support the hypothesis that early pregnancy signaling alters the proportions and functions of peripheral blood immune cells and differences between cows and heifers may yield insight into the reduced fertility of mature lactating dairy cows.

Dietary supplementation with rumen-protected capsicum during the transition period improves the metabolic status of dairy cows.

In ruminants, it has been observed that capsicum oleoresin can alter insulin responses and that high-intensity artificial sweetener can increase glucose absorption from the small intestine. Because glucose metabolism and insulin responses are critical during early lactation, these supplements might have an effect on the metabolic status of dairy cows during the transition period. The objective of this experiment was to evaluate the effects of rumen-protected capsicum oleoresin fed alone or in combination with artificial sweetener during the transition period on lactational performance and susceptibility to subclinical ketosis in dairy cows. Fifteen primiparous and 30 multiparous Holstein cows (a total of 39 cows finished the study) were arranged in a randomized complete block design during d -21 to 60 relative to parturition. Cows within block were randomly assigned to one of the following treatments: no supplement (CON), supplementation with 100 mg of rumen-protected capsicum/cow per day (RPCap), or RPCap plus 2 g of high-intensity artificial sweetener/cow per day (RPCapS). For both the RPCap and RPCapS treatments, only rumen-protected capsicum was fed during the dry period. From d 8 to 11 of lactation, intake was limited to 70% of predicted dry matter intake to induce subclinical ketosis. Production variables were recorded daily, samples for milk composition were collected on wk 2, 4, 6, and 8, and blood samples were collected on wk -2, 1, 2, and 4 of the experiment for analysis of metabolic hormones and blood cell counts. Supplementation with rumen-protected capsicum increased serum insulin and decreased ß-hydroxybutyrate concentrations precalving, indicating a decrease in lipolysis. During the lactation period, RPCap was associated with a trend for increased milk production and feed efficiency following the ketosis challenge. Supplementation with RPCapS appeared to negate the response to rumen-protected capsicum. All cows developed subclinical ketosis during the challenge, and this was not affected by treatment. We conclude that treatments did not decrease susceptibility to subclinical ketosis; however, dietary supplementation with rumen-protected capsicum was effective at improving energy status precalving and tended to increased milk production and feed efficiency. The mechanism underlying these responses is unclear.

Striatal dopamine mediates hallucination-like perception in mice.

Hallucinations, a central symptom of psychotic disorders, are attributed to excessive dopamine in the brain. However, the neural circuit mechanisms by which dopamine produces hallucinations remain elusive, largely because hallucinations have been challenging to study in model organisms. We developed a task to quantify hallucination-like perception in mice. Hallucination-like percepts, defined as high-confidence false detections, increased after hallucination-related manipulations in mice and correlated with self-reported hallucinations in humans. Hallucination-like percepts were preceded by elevated striatal dopamine levels, could be induced by optogenetic stimulation of mesostriatal dopamine neurons, and could be reversed by the antipsychotic drug haloperidol. These findings reveal a causal role for dopamine-dependent striatal circuits in hallucination-like perception and open new avenues to develop circuit-based treatments for psychotic disorders.

Phasmatodea (Arthropoda, Insecta) in Brazil: Status, New Record, and Proposal for Using Molecular Tools to Assist in Species Identification.

Phasmatodea (Arthropoda, Insecta) comprises phytophagous insects, popularly known as stick bugs because most of them resemble dry branches. Currently, more than 3000 species are known, the majority of which can be found in tropical regions of the world. In Brazil, it is estimated that there are approximately 200 species, but these numbers may not truly reflect the group's richness. A high degree of intraspecific polymorphism, a low number of specimens sampled, a shortage of specialized literature, and having only a small number of experts have amplified the difficulties in studying this order. Therefore, this study aims to present a historical survey of the Phasmatodea studies that have been conducted in Brazil thus far, indicating gaps in knowledge and discussing perspectives to expand understanding within this group. Furthermore, to the best our knowledge, the molecular characterization of the cytochrome oxidase subunit I gene of mitochondrial DNA of two species of phasmids found in Brazil, Cladomorphus phyllinus Gray, 1835, and Pseudophasma missionum Piza, 1981, is presented for the first time. In addition, this study records for the first time the occurrence of P. missionum in Brazilian territory.

Effects of 3-nitrooxypropanol on rumen fermentation, lactational performance, and resumption of ovarian cyclicity in dairy cows.

This study examined the effect of 3-nitrooxypropanol (3-NOP), a substance under investigation, on enteric methane (CH4) emission, rumen fermentation, lactational performance, sensory properties of milk, and the resumption of ovarian cyclicity in early-lactation dairy cows. Fifty-six multi- and primiparous Holstein cows, including 8 that were rumen cannulated, were used in a 15-wk randomized complete block design experiment. Cows were blocked based on parity and previous lactation milk yield (MY) or predicted MY, and within each block were randomly assigned to one of 2 treatments: (1) control (CON), administered no 3-NOP, or (2) 3-NOP applied at 60 mg/kg of feed dry matter (3-NOP). Enteric CH4 emission was measured during experimental wk 2, 6, 9, and 15, using the GreenFeed system. Dry matter intake (DMI) and MY data were collected daily throughout the experiment, and milk composition samples were collected 7 times during the experiment. Milk samples were collected from 14 to 60 (±2) d after calving, 3 d per week, and assayed for progesterone concentration to determine resumption of ovarian activity. Compared with CON, 3-NOP decreased daily CH4 emission by 26%, CH4 yield (CH4 per kg of DMI) by 21%, and CH4 emission intensity [CH4 per kg of MY or energy-corrected milk (ECM)] by 25%. Enteric emission of carbon dioxide was decreased by 5%, and hydrogen emission was increased 48-fold by 3-NOP. Inclusion of 3-NOP decreased concentration of total volatile fatty acids (by 9.3%) and acetate but increased butyrate molar proportion, ethanol, and formate concentrations in ruminal fluid. Dry matter intake was lower for 3-NOP compared with CON, but DMI expressed as a percentage of body weight was not different between treatments. Treatment had no effect on milk and ECM, body weight change, or body condition score. Milk composition and milk fat and protein yields were not affected by treatment, except that concentrations of short-chain fatty acids in milk were increased by 3-NOP. Nutrient digestibility and blood metabolites and hormones were not affected by 3-NOP, except that insulin was decreased by 3-NOP. There was no effect of 3-NOP on postpartum resumption of ovarian activity, including days to first and second luteal phases, length of first and second luteal phases, and interval from first to second luteal phase. Sensory properties of milk from cows fed 3-NOP and cheese made from that milk were not affected by treatment. In this experiment, 3-NOP decreased daily enteric CH4 emission, emission yield, and emission intensity, improved feed efficiency, and did not affect lactational performance or onset of ovarian activity in early-lactation dairy cows.

Production effects of feeding extruded soybean meal to early-lactation dairy cows.

The objective of this experiment was to evaluate productive and reproductive effects of replacing solvent-extracted soybean meal (SSBM) with extruded soybean meal (ESBM) in a total mixed ration for early-lactation dairy cows. Thirty-four Holstein cows (12 primiparous and 22 multiparous) were used in a randomized complete block design experiment with 17 cows per treatment. Feeding was ad libitum for 5 to 10% refusals. A fresh-cow diet was fed the first 21 d in milk followed by a lactation diet from 22 to 60 d in milk. Milk and dry matter intake data were collected throughout the experiment, and samples were collected for blood chemistry and amino acid profile, nutrient digestibility, nitrogen utilization, and enteric methane emission using the GreenFeed system (C-Lock Inc., Rapid City, SD). Dry matter intake, milk yield, and feed efficiency were not different between SSBM and ESBM. Energy-corrected milk yield and efficiency were also not different between diets. Diet had no effect on milk composition, except that milk true protein yield was decreased by ESBM. Enteric methane emission, yield, and intensity were not different between SSBM and ESBM. Because of its greater fat content, ESBM triggered expected changes in milk fatty acid (FA) profile: decreased sum of C16, saturated, and odd- and branched-chain FA and increased sum of preformed FA, polyunsaturated, and trans FA. The ESBM diet increased or tended to increase some essential amino acids in plasma. In this study, ESBM did not affect dry matter intake and did not improve lactational performance or onset of ovarian function in early-lactation dairy cows, and it decreased milk protein yield, possibly due to greater unsaturated FA intake compared with SSBM.

Test of the Einstein Equivalence Principle near the Galactic Center Supermassive Black Hole.

During its orbit around the four million solar mass black hole Sagittarius A* the star S2 experiences significant changes in gravitational potential. We use this change of potential to test one part of the Einstein equivalence principle: the local position invariance (LPI). We study the dependency of different atomic transitions on the gravitational potential to give an upper limit on violations of the LPI. This is done by separately measuring the redshift from hydrogen and helium absorption lines in the stellar spectrum during its closest approach to the black hole. For this measurement we use radial velocity data from 2015 to 2018 and combine it with the gravitational potential at the position of S2, which is calculated from the precisely known orbit of S2 around the black hole. This results in a limit on a violation of the LPI of |ß_{He}-ß_{H}|=(2.4±5.1)×10^{-2}. The variation in potential that we probe with this measurement is six magnitudes larger than possible for measurements on Earth, and a factor of 10 larger than in experiments using white dwarfs. We are therefore testing the LPI in a regime where it has not been tested before.

Self-diffusion in two-dimensional quasimagnetized rotating dusty plasmas.

The self-diffusion phenomenon in a two-dimensional dusty plasma at extremely strong (effective) magnetic fields is studied experimentally and by means of molecular dynamics simulations. In the experiment the high magnetic field is introduced by rotating the particle cloud and observing the particle trajectories in a corotating frame, which allows reaching effective magnetic fields up to 3000 T. The experimental results confirm the predictions of the simulations: (i) superdiffusive behavior is found at intermediate timescales and (ii) the dependence of the self-diffusion coefficient on the magnetic field is well reproduced.

[Algorithm for securing an unexpected difficult airway : User analysis on a simulator]. / Algorithmus zur Sicherung des unerwartet schwierigen Atemwegs : Eine Anwenderanalyse am Simulator.

BACKGROUND: Critical incidents in difficult airway management are still a main contributory factor for perioperative morbidity and mortality. Many national associations have developed algorithms for management of these time critical events. For implementation of these algorithms the provision of technical requirements and procedure-related training are essential. Severe airway incidents are rare events and clinical experience of the individual operators is limited; therefore, simulation is an adequate instrument for training and evaluating difficult airway algorithms. OBJECTIVE: The aim of this observational study was to evaluate the application of the institutional difficult airway algorithm among anesthetists. MATERIAL AND METHODS: After ethics committee approval, anesthetists were observed while treating a "cannot intubate" (CI) and a "cannot intubate, cannot ventilate" (CICV) situation in the institutional simulation center. As leader of a supportive team the participants had to deal with an unexpected difficult airway after induction of anesthesia in a patient simulator. The following data were recorded: sequence of the applied airway instruments, time to ventilation after establishing a secured airway using any instrument in the CI situation and time to ventilation via cricothyrotomy in the CICV situation. Conformity to the algorithm was defined by the sequence of the applied instruments. Analysis comprised conformity to the algorithm, non-parametric tests for time to ventilation and differences between junior and senior anesthetists. RESULTS: Out of 50 participants 45 were analyzed in the CI situation. In this situation 93% of the participants acted in conformity with the algorithm. In 62% the airway was secured by flexible intubation endoscopy, in 38% with another device. Data from 46 participants were analyzed in the CICV situation. In this situation 91% acted in conformity with the algorithm. The last device used prior to the decision for cricothyrotomy was flexible intubation endoscopy in 39%, a laryngeal mask in 22% and other instruments in 39%. Of the 50 participants 38 had already been institutionally trained in difficult airway management during the previous 2 years. For cricothyrotomy the participants needed a median time of 63 s and there was no difference between junior and senior anesthetists (p = 0.46). The cricothyrotomy was performed faster using a surgical approach than a transtracheal puncture approach using a Melker emergency cricothyrotomy set (52 s vs. 73 s, p = 0.014). CONCLUSION: The conformity to the algorithm of over 90% indicates a good training level of the participants concerning the difficult airway algorithm. In the observed sample flexible intubation endoscopy tended to be of high significance even in the unanticipated difficult airway. Cricothyrotomy was performed faster surgically than by the use of the transtracheal puncture approach, while no differences between junior and senior anesthetists were observed. For the successful management of an unexpected difficult airway, specific training of these special and rare events is crucial. A standardized provision of special airway instruments stored in a special trolley and frequent application of this trolley in the clinical routine is recommended.

The novel video-assisted intubating laryngeal mask Totaltrack compared to the intubating laryngeal mask Fastrach - a controlled randomized manikin study.

BACKGROUND: The novel Totaltrack combines a supraglottic airway device with video laryngoscopic tracheal intubation. The intubation laryngeal mask Fastrach is an established device without visual control of intubation. We hypothesized that supraglottic ventilation success with Totaltrack would be similar to Fastrach, but intubation would be performed faster due to visual control of the procedure. METHODS: Fifty-five anaesthesiologists were randomized into one of two study arms: Fastrach Totaltrack. After a standardized introduction, six consecutive attempts of supraglottic ventilation and intubation attempts with each of one of the devices were performed on an airway manikin. The combined primary outcome was: time to supraglottic ventilation and time to ventilation after intubation. Additionally, success rate and learning curves were evaluated. RESULTS: Supraglottic time to ventilation was shorter when using the Fastrach compared to the Totaltrack (median: 7.8 s [confidence interval [CI]: 7.0-8.6 s] vs. 11 s [CI: 7.8-14.2 s], P < 0.001). Intubation was faster using the Fastrach compared to Totaltrack (median: 12.5 s, [CI: 10.1-14.9 s] vs. 23.3 s [CI: 21.5-25.1 s], P < 0.001). Success rate for supraglottic ventilation was comparable between Fastrach and Totaltrack (86-96%). Successful intubation via the device was 100% in Fastrach and ranged from 61% to 93% in Totaltrack, with a higher probability of successful intubation after four applications. CONCLUSION: In this manikin-based study the novel Totaltrack did not prove superior to Fastrach despite a similar design. Video laryngoscopic control of supraglottic ventilation and endotracheal intubation was prolonged using the Totaltrack. Clinical trials are mandatory to evaluate the role of the Totaltrack in airway management.

Spontaneous generation of temperature anisotropy in a strongly coupled magnetized plasma.

A magnetic field was recently shown to enhance field-parallel heat conduction in a strongly correlated plasma whereas cross-field conduction is reduced. Here we show that in such plasmas, the magnetic field has the additional effect of inhibiting the isotropization process between field-parallel and cross-field temperature components, thus leading to the emergence of strong and long-lived temperature anisotropies when the plasma is locally perturbed. An extended heat equation is shown to describe this process accurately.

[Simulation-based training and OR apprenticeship for medical students : A prospective, randomized, single-blind study of clinical skills]. / Simulationsbasiertes Training und Lehre im OP für Studierende : Eine prospektive randomisierte, einfach verblindete Studie klinischer Fertigkeiten.

BACKGROUND: Simulation-based training (SBT) has developed into an established method of medical training. Studies focusing on the education of medical students have used simulation as an evaluation tool for defined skills. A small number of studies provide evidence that SBT improves medical students' skills in the clinical setting. Moreover, they were strictly limited to a few areas, such as the diagnosis of heart murmurs or the correct application of cricoid pressure. Other studies could not prove adequate transferability from the skills gained in SBT to the patient site. Whether SBT has an effect on medical students' skills in anesthesiology in the clinical setting is controversial. To explore this issue, we designed a prospective, randomized, single-blind trial that was integrated into the undergraduate anesthesiology curriculum of our department during the second year of the clinical phase of medical school. OBJECTIVES: This study intended to explore the effect of SBT on medical students within the mandatory undergraduate anesthesiology curriculum of our department in the operating room with respect to basic skills in anesthesiology. MATERIALS AND METHODS: After obtaining ethical approval, the participating students of the third clinical semester were randomized into two groups: the SIM-OR group was trained by a 225 min long SBT in basic skills in anesthesiology before attending the operating room (OR) apprenticeship. The OR-SIM group was trained after the operating room apprenticeship by SBT. During SBT the students were trained in five clinical skills detailed below. Further, two clinical scenarios were simulated using a full-scale simulator. The students had to prepare the patient and perform induction of anesthesia, including bag-mask ventilation after induction in scenario 1 and rapid sequence induction in scenario 2. Using the five-point Likert scale, five defined skills were evaluated at defined time points during the study period. 1) application of the safety checklist, 2) application of basic patient monitoring, 3) establishment of intravenous access, 4) bag-and-mask ventilation, and 5) adjustment of ventilatory parameters after the patients' airways were secured. A cumulative score of 5 points was defined as the best and a cumulative score of 25 as the worst rating for a defined time point. The primary endpoint was the cumulative score after day 1 in the operating room apprenticeship and the difference in cumulative scores from days 1 to 4. Our hypothesis was that the SIM-OR group would achieve a better score after day 1 in the operating room apprenticeship and would gain a larger increase in score from day 1 to day 4 than the OR-SIM group. RESULTS: 73 students were allocated to the OR-SIM group and 70 students to the SIM-OR group. There was no significant difference between the two groups after day 1 of the operating room apprenticeship and no difference in increase of the cumulative score from day 1 to day 4 (median of cumulative score on day 1: 'SIM-OR' 11.2 points vs. 'OR-SIM' 14.6 points; p = 0.067; median of difference from day 1 to day 4: 'SIM-OR' -3.7 vs. 'OR-SIM' -6.4; p = 0.110). CONCLUSION: With the methods applied, this study could not prove that 225 min of SBT before the operating room apprenticeship increased the medical students' clinical skills as evaluated in the operating room. Secondary endpoints indicate that medical students have better clinical skills at the end of the entire curriculum when they have been trained through SBT before the operating room apprenticeship. However, the authors believe that simulator training has a positive impact on students' acquisition of procedural and patient safety skills, even if the methods applied in this study may not mirror this aspect sufficiently.

Cage correlation and diffusion in strongly coupled three-dimensional Yukawa systems in magnetic fields.

The influence of an external homogeneous magnetic field on the quasilocalization of the particles-characterized quantitatively by cage correlation functions-in strongly coupled three-dimensional Yukawa systems is investigated via molecular dynamics computer simulations over a wide domain of the system parameters (coupling and screening strengths, and magnetic field). The caging time is found to be enhanced by the magnetic field B. The anisotropic migration of the particles in the presence of magnetic field is quantified via computing directional correlation functions, which indicate a more significant increase of localization in the direction perpendicular to B, while a moderate increase is also found along the B field lines. Associating the particles' escapes from the cages with jumps of a characteristic length, a connection is found with the diffusion process: the diffusion coefficients derived from the decay time of the directional correlation functions in both the directions perpendicular to and parallel with B are in very good agreement with respective diffusion coefficients values obtained from their usual computation based on the mean-squared displacement of the particles.

Effect of correlations on heat transport in a magnetized strongly coupled plasma.

In a classical ideal plasma, a magnetic field is known to reduce the heat conductivity perpendicular to the field, whereas it does not alter the one along the field. Here we show that, in strongly correlated plasmas that are observed at high pressure and/or low temperature, a magnetic field reduces the perpendicular heat transport much less and even enhances the parallel transport. These surprising observations are explained by the competition of kinetic, potential, and collisional contributions to the heat conductivity. Our results are based on first-principle molecular dynamics simulations of a one-component plasma.

Dynamics of two-dimensional one-component and binary Yukawa systems in a magnetic field.

We consider two-dimensional Yukawa systems in a perpendicular magnetic field. Computer simulations of both one-component and binary systems are used to explore the equilibrium particle dynamics in the fluid state. The mobility is found to scale with the inverse of the magnetic field strength (Bohm diffusion), for strong fields (ωc/ωp≳1). For bidisperse mixtures, the magnetic field dependence of the long-time mobility depends on the particle species, providing an external control of their mobility ratio. At large magnetic fields, the highly charged particles are almost immobilized by the magnetic field and form a porous matrix of obstacles for the mobile low-charge particles.

Special topics--Mitigation of methane and nitrous oxide emissions from animal operations: III. A review of animal management mitigation options.

The goal of this review was to analyze published data on animal management practices that mitigate enteric methane (CH4) and nitrous oxide (N2O) emissions from animal operations. Increasing animal productivity can be a very effective strategy for reducing greenhouse gas (GHG) emissions per unit of livestock product. Improving the genetic potential of animals through planned cross-breeding or selection within breeds and achieving this genetic potential through proper nutrition and improvements in reproductive efficiency, animal health, and reproductive lifespan are effective approaches for improving animal productivity and reducing GHG emission intensity. In subsistence production systems, reduction of herd size would increase feed availability and productivity of individual animals and the total herd, thus lowering CH4 emission intensity. In these systems, improving the nutritive value of low-quality feeds for ruminant diets can have a considerable benefit on herd productivity while keeping the herd CH4 output constant or even decreasing it. Residual feed intake may be a tool for screening animals that are low CH4 emitters, but there is currently insufficient evidence that low residual feed intake animals have a lower CH4 yield per unit of feed intake or animal product. Reducing age at slaughter of finished cattle and the number of days that animals are on feed in the feedlot can significantly reduce GHG emissions in beef and other meat animal production systems. Improved animal health and reduced mortality and morbidity are expected to increase herd productivity and reduce GHG emission intensity in all livestock production systems. Pursuing a suite of intensive and extensive reproductive management technologies provides a significant opportunity to reduce GHG emissions. Recommended approaches will differ by region and species but should target increasing conception rates in dairy, beef, and buffalo, increasing fecundity in swine and small ruminants, and reducing embryo wastage in all species. Interactions among individual components of livestock production systems are complex but must be considered when recommending GHG mitigation practices.

Magnetic field blocks two-dimensional crystallization in strongly coupled plasmas.

Crystallization in a two-dimensional strongly coupled plasma from a rapidly cooled fluid is found to be efficiently blocked by an external magnetic field. Beyond a threshold of the magnetic field strength B, the relaxation time to the equilibrium crystal increases exponentially with B, which is attributed to an impeded conversion of potential to kinetic energy. Our finding is opposed to the standard picture of two-dimensional freezing of one-component systems which does not exhibit a nucleation barrier and opens the way to keep two-dimensional fluids metastable over long times.

Technical options for the mitigation of direct methane and nitrous oxide emissions from livestock: a review.

Although livestock production accounts for a sizeable share of global greenhouse gas emissions, numerous technical options have been identified to mitigate these emissions. In this review, a subset of these options, which have proven to be effective, are discussed. These include measures to reduce CH4 emissions from enteric fermentation by ruminants, the largest single emission source from the global livestock sector, and for reducing CH4 and N2O emissions from manure. A unique feature of this review is the high level of attention given to interactions between mitigation options and productivity. Among the feed supplement options for lowering enteric emissions, dietary lipids, nitrates and ionophores are identified as the most effective. Forage quality, feed processing and precision feeding have the best prospects among the various available feed and feed management measures. With regard to manure, dietary measures that reduce the amount of N excreted (e.g. better matching of dietary protein to animal needs), shift N excretion from urine to faeces (e.g. tannin inclusion at low levels) and reduce the amount of fermentable organic matter excreted are recommended. Among the many 'end-of-pipe' measures available for manure management, approaches that capture and/or process CH4 emissions during storage (e.g. anaerobic digestion, biofiltration, composting), as well as subsurface injection of manure, are among the most encouraging options flagged in this section of the review. The importance of a multiple gas perspective is critical when assessing mitigation potentials, because most of the options reviewed show strong interactions among sources of greenhouse gas (GHG) emissions. The paper reviews current knowledge on potential pollution swapping, whereby the reduction of one GHG or emission source leads to unintended increases in another.

Wave spectra of a strongly coupled magnetized one-component plasma: quasilocalized charge approximation versus harmonic lattice theory and molecular dynamics.

Two different approaches to the calculation of the wave spectra of magnetized strongly coupled liquid one-component plasmas are analzyed: the semianalytical quasilocalized charge approximation (QLCA) and the angle-averaged harmonic lattice (AAHL) theory. Both theories are benchmarked against the numerical evidence obtained from molecular dynamics simulations. It is found that not too far from the melting transition (Γ≳100), the AAHL theory is superior to the QLCA, while further away from the transition, the QLCA performs comparably to or better than the AAHL theory.

Hot topic: association of telomere length with age, herd, and culling in lactating Holsteins.

Telomere length variation may provide a quantitative measure of the effects of dairy management and selection practices on animal stress and welfare. The objective of this study was to evaluate the association between telomere length in Holstein cattle with age, herd, and survival. A multiplex quantitative PCR (qPCR) procedure was utilized to estimate telomere length for 201 Holstein cows from 10 herds following DNA extraction from blood. Primers were designed to amplify a 79-bp telomere product and a 144-bp product of a standard reference gene (ß-globin). Both primer sets were included in the same reaction well to enable the analysis of relative quantity (qT) of telomere product compared with ß-globin product. Triplicate samples were run for each cow, and mixed models were used to analyze the qPCR results. Younger cows were significantly associated with higher qT, and significant variation was observed among herds for qT. Cows with short telomeres were more likely to be culled in the subsequent year than cows with above-average telomere lengths. Multiplex qPCR provides a cost-effective method of assessing telomere length. Variation in telomere length might provide insights into how management practices and genetic selection influence cow stress and physiological responses to stress.