Predicting dairy cattle heat stress using machine learning techniques.

The objectives of the study were to use a heat stress scoring system to evaluate the severity of heat stress on dairy cows using different heat abatement techniques. The scoring system ranged from 1 to 4, where 1 = no heat stress; 2 = mild heat stress; 3 = severe heat stress; and 4 = moribund. The accuracy of the scoring system was then predicted using 3 machine learning techniques: logistic regression, Gaussian naïve Bayes, and random forest. To predict the accuracy of the scoring system, these techniques used factors including temperature-humidity index, respiration rate, lying time, lying bouts, total steps, drooling, open-mouth breathing, panting, location in shade or sprinklers, somatic cell score, reticulorumen temperature, hygiene body condition score, milk yield, and milk fat and protein percent. Three different treatments, namely, portable shade structure, portable polyvinyl chloride pipe sprinkler system, or control with no heat abatement, were considered, where each treatment was replicated 3 times with 3 second-trimester lactating cows. Results indicate that random forest outperformed the other 2 methods, with respect to both accuracy and precision, in predicting the sprinkler group's score. Both logistic regression and random forest were consistent in predicting scores for control, shade, and combined groups. The mean probability of predicting non-heat-stressed cows was highest for cows in the sprinkler group. Finally, the logistic regression method worked best for predicting heat-stressed cows in control, shade, and combined. The insights gained from these results could aid dairy producers to detect heat stress before it becomes severe, which could decrease the negative effects of heat stress, such as milk loss.

Graduate Student Literature Review: Heat abatement strategies used to reduce negative effects of heat stress in dairy cows.

The southeastern United States experiences an extended hot season with a high environmental temperature and relative humidity. With increasing global temperatures, managing dairy cattle in regions with tropical, subtropical, and Mediterranean climates is becoming an increasing challenge. Heat-stressed cows will decrease feed intake, decrease productivity, and increase respiration rate in an attempt to maintain internal body temperature. Temperature-humidity index (THI) is a unitless value that has been used to measure the magnitude of heat stress on dairy cows. Many researchers have studied the THI threshold at which dairy cattle begin to experience heat stress. When housing cows in a confinement setting, a pasture-based setting, or a combination of the two, the appropriate heat abatement should be implemented to allow cows to perform to their potential and to improve overall animal welfare. This review summarizes heat abatement strategies that have been studied to reduce the negative effects of heat stress.

Invited review: Physiological and behavioral effects of heat stress in dairy cows.

Animal welfare can be negatively affected when dairy cattle experience heat stress. Managing heat stress has become more of a challenge than ever before, due to the increasing number of production animals with increased milk yield, and therefore greater metabolic activity. Environmental temperatures have increased by 1.0°C since the 1800s and are expected to continue to increase by another 1.5°C between 2030 and 2052. Heat stress affects production, reproduction, nutrition, health, and welfare. Means exist to monitor and evaluate heat stress in dairy cattle, as well as different ways to abate heat, all with varying levels of effectiveness. This paper is a summary and compilation of information on dairy cattle heat stress over the years.

Influence of breed, milk yield, and temperature-humidity index on dairy cow lying time, neck activity, reticulorumen temperature, and rumination behavior.

The objective of this study was to compare weekly mean lying time (LT), neck activity (NA), reticulorumen temperature (RT), and rumination time (RU) among 3 breed groups, milk yield (MY), and temperature-humidity index (THI). Cows (n = 36; 12 Holstein, 12 crossbred, and 12 Jersey) were blocked by parity group (primiparous or multiparous), days in milk, and MY. Lying time, NA, RT, RU, and MY were recorded and averaged by day and then by week for each cow. For study inclusion, each cow was required to have 10 wk of LT, NA, RT, and RU data. Maximum THI were recorded and averaged daily. Mean (±SE) days in milk, LT, MY, RT, RU, NA, and maximum THI were 159.0 ± 6.0 d, 11.1 ± 0.1 h/d, 28.7 ± 0.5 kg/d, 38.8 ± 0.0°C, 6.4 ± 0.1 h/d, 323.8 ± 3.8 activity units, and 56.5 ± 0.6, respectively. The MIXED Procedure of SAS (SAS Institute Inc., Cary, NC) was used to evaluate fixed effects of breed, MY, parity, THI, and their interactions on LT, NA, RT, and RU with cow nested within breed as subject. All main effects remained in each model regardless of significance level. Stepwise backward elimination was used to remove nonsignificant interactions. The interactions of breed × parity group and maximum THI × parity group were associated with RT. Increasing THI coincided with increasing RT. Least squares means LT for multiparous cows was significantly greater than LT for primiparous cows (11.4 ± 0.3 and 10.5 ± 0.5 h/d, respectively). Least squares means NA for primiparous cows was greater than for multiparous cows of all breeds (372.1 ± 10.9 and 303.4 ± 7.8, respectively). The CORR Procedure of SAS was used to evaluate relationships among RT, RU, LT, NA, and MY. Rumination time was positively correlated with MY (r = 0.30) and negatively correlated with LT (r = -0.14). Reticulorumen temperature was negatively correlated with MY (r = -0.11). Rumination time was positively correlated with NA (r = 0.18) and negatively correlated with LT (r = -0.14). Lying time and NA were negatively correlated (r = -0.43). Neck activity was positively correlated with MY (r = 0.14). Lying time was negatively correlated with MY (r = -0.25). Milk yield was associated with RU, which may be related to cows with greater MY also having a greater feed intake. Lying time increased and NA decreased with increasing parity, which may be effects of social hierarchy, where primiparous cows are more susceptible to being pushed away from the feed bunk and freestalls. Milk yield was positively associated with RU. Greater milk production requires greater feed intake, which may result in longer RU than for low-yielding cows. Lying time decreased as milk yield increased. The behavioral and physiological differences observed in this study provide new insight into the effects that breed, parity, MY, and THI have on cows.

Vacancy dissociation in body-centered cubic screw dislocation cores.

The interaction between screw dislocations and vacancies in body-centered cubic metals is investigated using molecular dynamics simulations. For thirteen different classical interatomic potentials, materials properties relating to vacancies, dislocations, and the interaction between the two are evaluated. The potentials include six for iron, two for molybdenum, and five for tantalum, and they are a mix of embedded atom method (EAM), modified embedded atom method (MEAM), and angular dependent potential (ADP) styles. A previously unknown behavior was identified during the interaction simulations. Out of the thirteen potentials investigated, ten predict a vacancy on the dislocation core to no longer remain as a discrete point defect, but rather to dissociate along the dislocation line. The structure of the dissociation is dependent on the potential and is characterized here. As this vacancy dissociation alters the core structure of the dislocation, it may prove to be a new mechanism for dislocation pinning and pipe diffusion.

Identification of three CCp genes in Babesia divergens: novel markers for sexual stages parasites.

Babesia divergens, a tick-borne protozoan parasite of red blood cells, is the main agent of bovine and human babesiosis in Europe. Very few data are available concerning its life cycle and sexual reproduction inside the tick vector, Ixodes ricinus. The aim of this study was to define some markers of the B.divergens sexual stage. An in silico post-genomic approach was used to analyze genomic, transcriptomic and proteomic data and to select specific sexual stage proteins of the related apicomplexan genus Plasmodium. Three proteins, based on sequence identity between the available genomes of Plasmodium and Babesia spp., were chosen, as members of a highly conserved and apicomplexan sexual stages specific protein family (CCp) potentially involved in adhesive functions. Degenerate primers were used to amplify and clone three B.divergens orthologs (bdccp1, bdccp2, and bdccp3) corresponding to newly identified genes in this parasite. The opportunities offered by such markers to study parasite development in its vector are discussed.

Crystal-melt interface stresses: atomistic simulation calculations for a Lennard-Jones binary alloy, Stillinger-Weber Si, and embedded atom method Ni.

Molecular-dynamics and Monte Carlo simulations have been used to compute the crystal-melt interface stress (f) in a model Lennard-Jones (LJ) binary alloy system, as well as for elemental Si and Ni modeled by many-body Stillinger-Weber and embedded-atom-method (EAM) potentials, respectively. For the LJ alloys the interface stress in the (100) orientation was found to be negative and the f vs composition behavior exhibits a slight negative deviation from linearity. For Stillinger-Weber Si, a positive interface stress was found for both (100) and (111) interfaces: f{100}=(380+/-30)mJ/m{2} and f{111}=(300+/-10)mJ/m{2}. The Si (100) and (111) interface stresses are roughly 80 and 65% of the value of the interfacial free energy (gamma) , respectively. In EAM Ni we obtained f{100}=(22+/-74)mJ/m{2}, which is an order of magnitude lower than gamma. A qualitative explanation for the trends in f is discussed.

Atomistic underpinnings for orientation selection in alloy dendritic growth.

In dendritic solidification, growth morphologies often display a pronounced sensitivity to small changes in composition. To gain insight into the origins of this phenomenon, we undertake an atomistic calculation of the magnitude and anisotropy of the crystal-melt interfacial free energy in a model alloy system featuring no atomic size mismatch and relatively ideal solution thermodynamics. By comparing the results of these calculations with predictions from recent phase-field calculations, we demonstrate that alloying gives rise to changes in free-energy anisotropies that are substantial on the scale required to induce changes in growth orientations.

Equilibrium adsorption at crystal-melt interfaces in Lennard-Jones alloys.

Although the properties of crystal-melt interfaces have been extensively studied in pure materials, effects of alloying on the interfacial free energy remain relatively poorly understood. In this work we make use of Monte Carlo computer simulations for model binary Lennard-Jones alloys to explore the effects which variations in atomic-size mismatch and the chemical contributions to mixing energies have upon density and composition profiles, as well as the resulting magnitudes of equilibrium adsorption coefficients in concentrated alloys. We study four different model systems covering a range of chemical and size mismatch, finding relatively small adsorption values which are nevertheless statistically different from zero.

Sound concept, unhealthy in practice ... but at great expense to providers and patients.

Those states considering implementation of a TennCare-type program should learn from Tennessee's mistakes. Enough lead time should be allowed for the development of the program and for patients and providers to learn about the new program. It should be actuarially should and have strong oversight with provider input. Finally, it should be done in an open forum to allow public accountability.

A randomized trial of treatment options for alcohol-abusing workers.

BACKGROUND: Employee-assistance programs sponsored by companies or labor unions identify workers who abuse alcohol and refer them for care, often to inpatient rehabilitation programs. Yet the effectiveness of inpatient treatment, as compared with a variety of less intensive alternatives, has repeatedly been called into question. In this study, anchored in the work site, we compared the effectiveness of mandatory in-hospital treatment with that of required attendance at the meetings of a self-help group and a choice of treatment options. METHODS: We randomly assigned a series of 227 workers newly identified as abusing alcohol to one of three rehabilitation regimens: compulsory inpatient treatment, compulsory attendance at Alcoholics Anonymous (AA) meetings, and a choice of options. Inpatient backup was provided if needed. The groups were compared in terms of 12 job-performance variables and 12 measures of drinking and drug use during a two-year follow-up period. RESULTS: All three groups improved, and no significant differences were found among the groups in job-related outcome variables. On seven measures of drinking and drug use, however, we found significant differences at several follow-up assessments. The hospital group fared best and that assigned to AA the least well; those allowed to choose a program had intermediate outcomes. Additional inpatient treatment was required significantly more often (P less than 0.0001) by the AA group (63 percent) and the choice group (38 percent) than by subjects assigned to initial treatment in the hospital (23 percent). The differences among the groups were especially pronounced for workers who had used cocaine within six months before study entry. The estimated costs of inpatient treatment for the AA and choice groups averaged only 10 percent less than the costs for the hospital group because of their higher rates of additional treatment. CONCLUSIONS: Even for employed problem drinkers who are not abusing drugs and who have no serious medical problems, an initial referral to AA alone or a choice of programs, although less costly than inpatient care, involves more risk than compulsory inpatient treatment and should be accompanied by close monitoring for signs of incipient relapse.

Chronic antidepressant and clonidine treatment effects on conflict behavior in the rat.

The present studies examined the effects of chronic treatment with several antidepressants and clonidine on conflict behavior. In daily ten-minute sessions, water-deprived rats were trained to drink from a tube which was occasionally electrified (0.25 or 0.5 mA). Electrification was signalled by a tone. Chronic desipramine (5 mg/kg, IP, b.i.d.) or clonidine (40 micrograms/kg, b.i.d.) treatment resulted in time-dependent anticonflict effects, with a latency to onset of approximately 3-4 weeks. In contrast, chronic buproprion (up to 10 mg/kg, IP, b.i.d.), mianserin (up to 10 mg/kg, IP, b.i.d.) or trazodone (up to 40 mg/kg, IP, b.i.d.) treatment resulted in at best only a weak anticonflict effect. The efficacy of these antidepressants and clonidine to increase punished responding when administered chronically correlates well with their efficacy as antipanic agents in man.

Endothelial response to perfluorochemical perfusion.

The purpose of this study was to evaluate, in vivo, the effect of perfluorochemical (PFC) blood substitutes on arterial endothelium following total blood replacement. Conscious-female-Sprague-Dawley rats (150-200 gms) were isovolumically exchange perfused with 3 blood volumes of PFC emulsion in an oxygen chamber. The exchange was performed at 0.5 ml/min via an indwelling-intracardiac-double-lumen catheter. One hour after the exchange, the animal was sacrificed and the circulatory system flushed free of blood and PFC emulsion with Dulbecco's solution, followed by perfusion fixation with glutaraldehyde solution. The heart, lungs and thoracic aorta were excised. The pulmonary arterial endothelial cell response was determined by scanning electron microscopy (SEM) following acute exposure to PFC emulsions under conditions of varied pH, oncotic pressure and emulsion age. These endothelial surfaces exhibited increased microvilli, leukocyte adhesion, fibrin deposition and subendothelium exposure. The magnitude of these abnormal responses varied with the degree of alkalinity and reduced oncotic pressure of the perfusate.

Semantic context effects in visual word recognition, sentence processing, and reading: evidence for semantic strategies.

Earlier research studying the effects of semantic context on single words suggested that subjects may have two strategies for using a context (Becker, 1980). The present research finds that the semantic context strategies may be used in reading short sentences. Further, individual differences in context effects both in a word-level task and in a sentence-level task are related to individual differences in reading continuous text. These results are presented within the framework of the verification model (Becker, 1976, 1980), and the implications for two-process theory (Stanovich & West, 1979, 1981) are discussed.