720 research outputs found
Grounding Size Predictions for Answer Set Programs
Answer set programming is a declarative programming paradigm geared towards solving difficult combinatorial search problems. Logic programs under answer set semantics can typically be written in many different ways while still encoding the same problem. These different versions of the program may result in diverse performances. Unfortunately, it is not always easy to identify which version of the program performs the best, requiring expert knowledge on both answer set processing and the problem domain. More so, the best version to use may even vary depending on the problem instance. One measure that has been shown to correlate with performance is the programs grounding size, a measure of the number of ground rules in the grounded program (Gebser et al. 2011). Computing a grounded program is an expensive task by itself, thus computing multiple ground programs to assess their sizes to distinguish between these programs is unrealistic. In this research, we present a new system called PREDICTOR to estimate the grounding size of programs without the need to actually ground/instantiate these rules. We utilize a simplified form of the grounding algorithms implemented by answer set programming grounder DLV while borrowing techniques from join-order size estimations in relational databases. The PREDICTOR system can be used independent of the chosen answer set programming grounder and solver system. We assess the accuracy of the predictions produced by PREDICTOR, while also evaluating its impact when used as a guide for rewritings produced by the automated answer set programming rewriting system called PROJECTOR. In particular, system PREDICTOR helps to boost the performance of PROJECTOR
Attitudes Toward Marriage and Long-term Relationships across Emerging Adulthood
The current study expands upon existing developmental research on marital attitude change by examining how attitudes toward marriage and long-term relationships may vary across emerging adulthood. Utilizing five waves of data from the Center on Young Adult Health and Development’s College Life Study, discrete-time survival analysis and latent basis growth curve analysis are employed to assess the change—and predictors of such change—in three measures of relationship attitudes (desire for marriage, desire for long-term relationships, and importance of marriage and long-term relationships) of over 900 college students. Results indicate positive change in all three measures of attitudes, with most emerging adults desiring and placing importance on marriage and long-term relationships from the very beginning of college. Predictors of attitude change included sex, race, experience of parental death, student status, educational aspirations, and total number of sex partners. Results suggest a need for more longitudinal research in this area
Identification of the substrate specificity of three intracellular PTP\u27s (PTP-1, PTP-5, and YOP-51) and two transmembrane PTP\u27s (CD45 and LAR) and evidence for an active site arginine residue
This study has investigated the interaction of protein tyrosine phosphatases (PTP\u27s) with their substrates both at the level of recognition and catalysis using three approaches. First, the one mechanism for substrate recognition by three intracellular PTP\u27s (PTP-1, PTP-5, and YOP-51) and two transmembrane PTP\u27s (CD45 and LAR). Acidic residues in several positions were found to affect peptide reactivity with all the PTP\u27s tested. The intracellular PTP\u27s that were tested all had similar responses to N-terminal acidic residues, but were quite distinct from the transmembrane PTP\u27s (CD45 and LAR), which were also found to differ from one another. The second approach addressed whether these PTP\u27s show a broad or narrow substrate specificity using a variety of peptides corresponding to tyrosine phosphorylation sites of proteins that are known or believed to be physiologically relevant PTP substrates. These experiments found that all five PTP\u27s had a broad substrate specificity. However, each PTP did show some ability to discriminate amongst these peptides, and the magnitude of this discrimination was found to vary from PTP to PTP (from 400-fold for YOP-51 to 22-fold for CD45). Using these divergant peptides, the three intracellular PTP\u27s were once again found to have similar substrate specificities, and this specificity was quite distinct from that of either CD45 or LAR. Additionally, CD45 and LAR were also found to have different substrate specificities. To get a better understanding of how PTP\u27s carry out substrate recognition and catalysis, chemical modification studies were performed to search for active site residues in PTP-1. The arginine specific modifying reagent, phenylglyoxal, was found to inactivate PTP-1 and kinetic analysis of this reaction indicated that only one mole of phenylglyoxal was needed to inactivate one mole of PTP-1. Furthermore, this inactivation could be inhibited by a peptide substrate, consistent with the modified arginine residue being in the active site. Additional studies using (7-[superscript]14C) phenylglyoxal indicated that two arginine residues were being modified. Studies are currently under way to determine whether inactivation corresponds to modification of one, or both arginine residues
Metabolic responses of dairy cows with fatty liver to treatment with glucagon
To test the hypothesis that glucagon will decrease the severity of fatty liver and prevent ketosis, glucagon was continuously infused via intravenous jugular catheters into dairy cattle in several physiological states. In preliminary dosage response studies, glucagon was infused into eight spayed Holstein heifers, four midlactation Holstein cows, and four early-lactation Brown Swiss cows in cross-over design trials at dosages of 20 mg/d or less for 48 h. Plasma glucose concentrations were increased by glucagon in a dose-dependent manner. Plasma nonesterified fatty acid and ketone body concentrations were not increased by glucagon at 5 mg/d or less, were increased in heifers at 10 mg/d, and increased in cows at 20 mg/d compared with preinfusion concentrations. Glucagon at 10 mg/d was the largest dosage tested in lactating cows that did not elicit a lipolytic or ketogenic response. Glucagon at 10 mg/d or vehicle then was infused for 14 d during a protocol to induce ketosis in 20 early-lactation Holstein cows already having fatty livers. Plasma glucose concentrations were increased by 42% by glucagon. Insulin concentrations increased during the first 4 h of glucagon infusion, thereafter they were not different than concentrations in plasma of control cows. Concentrations of nonesterified fatty acids and ketone bodies in plasma were decreased over time by glucagon compared with concentrations in plasma of control cows. In livers of cows treated with glucagon, concentrations of triacylglycerols rapidly and dramatically declined. At the end of glucagon treatment, triacylglycerol concentrations in livers of glucagon-treated cows had been decreased by 71% compared with livers of control cows. Glucagon caused liver glycogen concentrations to transiently decrease and ultimately increase to 231% of the glycogen concentrations in livers of control cows. Production of milk and milk protein was decreased during glucagon treatment but rapidly increased to levels of production by control cows after treatment. No adverse effects of glucagon were observed on the health of the cows. In summary, glucagon can be used as an effective treatment for fatty liver and increasing the resistance of early-lactation cows to ketosis
The intellectual and moral integrity of bioethics: response to commentaries on A case study in unethical transgressive bioethics: \u27Letter of concern from bioethicists\u27 about the prenatal administration of dexamethasone .
In our target article we showed that the Letter of Concern (LoC) fails to meet accepted standards for presenting empirical data for the purpose of supplementing a normative claim and for argument-based normative ethics. The LoC fails to meet the standards of evidence-based reasoning by making false claims, failing to reference data that undermine its key premises, and misrepresenting and misinterpreting the scientific publications it selectively references. The LoC fails to meet the standards of argument-based reasoning by treating as settled matters what are, instead, ongoing controversies, offering “mere opinion” as a substitute for argument, and making contradictory claims. The LoC is methodologically defective and thus a case study in unethical transgressive bioethics. Not withdrawing the LoC will damage the field of bioethics, making this case study in unethical transgressive bioethics important for the entire field
Feeding Dairy Cows for Body Condition Score
Changes in body weight are not a very good indicator of the nutritional status of dairy cows. For example, while the gut contents of a 1400 lb. dairy cow weigh approximately 200 lbs., the cow has a daily intake of nearly 100 lbs. of feed (fresh weight) and 160 to 240 lbs. of water (one gallon equals 8 lbs). In addition, the cow outputs over 120 lbs. of fresh manure and urine per day (NRC 2001), as well as 50 to 100-plus lbs. of milk. Thus, the ability to accurately depict actual changes in body mass via body weight measurements can be affected by daily fluctuations in body weight. A better method of evaluating the nutritional status of cows is through its body condition score (BCS). Body condition scoring, while subjective, is a useful and practical visual assessment tool of the nutritional status of cattle. High percentages of repeatability, both between measurements and between scorers, can be obtained with practice. The scoring system usually in use for dairy cattle is a 5-point scale, with 1 corresponding to an extremely thin cow, and 5 to a cow with excessive fat deposits (Wildman et al. 1982). Photos of and a text description for each body condition score are provided at the conclusion of this publication
Preventative Feeding of the Dairy Cow in Transition
The transition period in the lactating dairy cow is characterized by decreased feed intake that starts late in the close-up period and recovers several days after calving. This drop in intake results in an imbalance between required and absorbed nutrients. Other factors that are related to the volume and physical form of the feed can lead to problems frequently observed at calving time. In general, the veterinary diagnosis is based upon clinical symptoms of certain ailments. For greater chances of success and decreased treatment costs, it’s necessary to detect these ailments during their subclinical stage, or, better yet, to prevent their occurrence
https://www.cambridge.org/core/journals/theory-and-practice-of-logic-programming/article/system-predictor-grounding-size-estimator-for-logic-programs-under-answer-set-semantics/9EE3D47F0DCDA77E39328E53B0816CD9#:~:text=System%20Predictor%3A%20Grounding%20Size%20Estimator%20for%20Logic%20Programs%20under%20Answer%20Set%20Semantics
Answer set programming is a declarative logic programming paradigm geared towards solving difficult combinatorial search problems. While different logic programs can encode the same problem, their performance may vary significantly. It is not always easy to identify which version of the program performs the best. We present the system PREDICTOR (and its algorithmic backend) for estimating the grounding size of programs, a metric that can influence a performance of a system processing a program. We evaluate the impact of PREDICTOR when used as a guide for rewritings produced by the answer set programming rewriting tools PROJECTOR and LPOPT. The results demonstrate potential to this approach
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