Absence makes the adaptations grow fonder: Proportion of time apart from partner, male sexual psychology, and sperm competition in humans (Homo sapiens).

Sperm competition occurs when the sperm of multiple males concurrently occupy the reproductive tract of a female and compete to fertilize an egg. We used a questionnaire to investigate psychological responses to the risk of sperm competition for 237 men in committed, sexual relationships. As predicted, a man who spends a greater (relative to a man who spends a lesser) proportion of time apart from his partner since the couple's last copulation reported (a) greater sexual interest in his partner, (b) greater distress in response to his partner's sexual rejection, and (c) greater sexual persistence in response to his partner's sexual rejection. All effects were independent of total time since the couple's last copulation and the man's relationship satisfaction. Discussion addresses limitations of the current research and situates the current results within the broader comparative literature on adaptation to sperm competition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evaluation of Longissimus dorsi muscle pH at three hours Post mortem as a predictor of beef tenderness

The objective of this study was to determine the relationship of beef longissimus dorsi muscle (LM) pH at 3 h post mortem (pH(3)) and aged LM tenderness. The cattle (n = 444) sampled for this experiment represented various breed types, sex classes, feeding regimes, and post-mortem handling practices. The phenotypic diversity of the cattle used provided a great amount of variation in Warner-Bratzler shear (WBS) force (Coefficient of variation for pH, temperature, and sarcomere length measurements were much smaller than the coefficient of variation for WBS force). None of the parameters measured (LM pH at 3 and 48 h post mortem, temperature at 3 h post mortem and sarcomere length) was strongly related to tenderness. These results do not support the use of pH(3) as a criterion for sorting beef carcasses into expected tenderness groups.     

Effects of feeding diets containing different fat supplements to swine on the visual properties and storage stability of low-fat sausage

Sixty barrows and gilts were assigned to one of five dietary treatments consisting of a control diet of corn and soybean meal and four similar test diets that contained a 10% replacement of either animal fat, safflower oil, sunflower oil or canola oil, to determine the effects of high levels of oleic acid in the diet of swine on the storage stability of fresh pork sausage. Pork trim from each treatment was used to formulate sausage that contained two fat levels (25% and 35%), and two levels of added water (3% and 11%). Thiobarbituric acid values did not differ between the control, safflower oil or sunflower oil treatments and all treatments were acceptable after 10 weeks of storage. Microbial numbers increased with the level of added water and during time in storage (up to 3 weeks). Visual evaluation showed that the control was the most red and least discolored, while the canola oil treatment was the least red and the most discolored. Results from the present study suggest that a 105 replacement of a typical corn/soybean meal diet to swine with safflower or sunflower oil did not alter the storage-stability of fresh pork sausage.     

Psychological and Physiological Adaptations to Sperm Competition in Humans.

Postcopulatory competition between males, in the form of sperm competition, is a widespread phenomenon in many animal species. The extent to which sperm competition has been an important selective pressure during human evolution remains controversial, however. The authors review critically the evidence that human males and females have psychological, behavioral, and physiological adaptations that evolved in response to selection pressures associated with sperm competition. The authors consider, using evidence from contemporary societies, whether sperm competition is likely to have been a significant adaptive problem for ancestral humans and examine the evidence suggesting that human males have physiological and psychological mechanisms that allow for "prudent" sperm allocation in response to variations in the risk of sperm competition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparative evolutionary psychology of sperm competition.

A comparative evolutionary psychological perspective predicts that species that recurrently faced similar adaptive problems may have evolved similar psychological mechanisms to solve these problems. Sperm competition provides an arena in which to assess the heuristic value of such a comparative evolutionary perspective. The sperm competition that results from female infidelity and polyandry presents a similar class of adaptive problems for individuals across many species. The authors first describe mechanisms of sperm competition in insects and in birds. They suggest that the adaptive problems and evolved solutions in these species provide insight into human anatomy, physiology, psychology, and behavior. The authors then review recent theoretical and empirical arguments for the existence of sperm competition in humans and discuss proposed adaptations in humans that have analogs in insects or birds. The authors conclude by highlighting the heuristic value of a comparative evolutionary psychological approach in this field. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of the callipyge phenotype and cooking method on tenderness of several major lamb muscles

We conducted three experiments to determine the effects of the callipyge phenotype on the tenderness of several major lamb muscles and to determine the effect of method of cookery on the tenderness of callipyge lamb at 7 d postmortem. In Exp. 1, chops from normal (n = 23) and callipyge (n = 16) carcasses were open-hearth-broiled. Warner-Bratzler shear force values of longissimus, gluteus medius, semimembranosus, biceps femoris, semitendinosus, adductor, and quadriceps femoris were 123, 44, 28, 26, 19, 16, and 13% greater, respectively, for callipyge (P < .05). In Exp. 2, muscles from normal (n = 18) and callipyge (n = 18) carcasses were oven-roasted. Shear force of triceps brachii was 11% greater for callipyge (P < .001); however, phenotype did not affect shear force of supraspinatus (P = .87) or psoas major (P = .64). In Exp. 3, a trained sensory panel evaluated leg roasts and open-hearth-broiled leg chops from normal (n = 60) and callipyge lamb carcasses (n = 60). Callipyge chops were less tender than normal chops (P < .05). Regardless of callipyge phenotype, muscles were more (P < .05) tender when roasted; however, the effect of method of cookery on tenderness scores was greater for callipyge muscles than for normal muscles. Callipyge roasts and normal roasts had similar tenderness (P = .58), and callipyge roasts were more tender than normal chops (P < .05). Regardless of cooking method, callipyge samples were less juicy than normal samples (P < .05). These data demonstrate that the callipyge phenotype will likely reduce consumer satisfaction due to reduced tenderness and juiciness; however, reduced tenderness in callipyge leg muscles could be prevented by ovenroasting.     

Decreased dosage of acidified sodium chlorite reduces microbial contamination and maintains organoleptic qualities of ground beef products

Acidified sodium chlorite (ASC) spray was evaluated at decreased dosages and application rates to determine its efficacy for reducing bacterial contamination on boneless beef trimmings used for production of raw ground beef products while maintaining desirable consumer qualities in the finished ground beef products. Two different applications of ASC (600 ppm applied at a rate of 1.3 oz/lb and 300 ppm applied at a rate of 1 oz/lb) were used to treat boneless beef trimmings before grinding. The effect of ASC treatment on 50/50 lean beef trimmings was greater than on 90/10 trimmings. ASC at 600 ppm reduced both the aerobic plate counts (APC) and Enterobacteriaceae counts (EBC) by 2.3 log CFU/g on 50/50 trimmings, whereas treatment with 300 ppm ASC reduced APC and EBC of 50/50 trimmings by 1.1 and 0.7 log CFU/g, respectively. Ground beef formulations of 90/10 and 73/27 were produced from the treated boneless beef trim and packaged in chubs and in modified atmosphere packaging. The efficacy of ASC spray treatment to inhibit APC and EBC over the shelf life of each ground beef product was monitored. The APC and EBC in ground beef chubs were reduced by 1.0 to 1.5 log CFU/g until day 20. The APC and EBC for products in modified atmosphere packaging were reduced 1.5 to 3.0 log CFU/g throughout their shelf life. Both decreased dosages of ASC were equally effective on 90/10 lean ground beef, but the 300 ppm ASC treatment was slightly better at reducing the EBC of 73/27 ground beef. The organoleptic qualities (color, odor, and taste) of the ground beef products treated with 300 ppm ASC were found to be superior to those treated with 600 ppm ASC. Our results indicated that decreased dosages of ASC reduce contamination and lengthen the shelf life of ground beef. Furthermore, the 300 ppm ASC treatment reduced bacterial counts while maintaining desirable organoleptic ground beef qualities.     

Chemico-Osmotic Efficiency of a Geosynthetic Clay Liner

Chemico-osmotic efficiency coefficients, ω, are determined from measured differential pressures across specimens of a geosynthetic clay liner (GCL) containing granular bentonite in response to applied differences in potassium chloride (KCl) concentrations under no-flow conditions. The results show that the GCL acts as a semipermeable membrane with ω values at steady state, ωss, ranging from 0.08 to 0.69 for KCl concentration differences ranging from 0.0039 to 0.047 M. The chemico-osmotic efficiency of the GCL decreases with increasing porosity and increasing KCl concentration. The decrease in ωss with increasing porosity is consistent with an increase in pore size reflected by an increase in measured hydraulic conductivity. The decrease in ωss with increasing KCl concentration is consistent with compression of the diffuse double layers surrounding the clay particles, and is reflected by a time-dependent decrease in the induced differential pressure as well as an increase in the hydraulic conductivity of the specimen. The results of this study are potentially significant with respect to the evaluation of the hydraulic and contaminant transport performance of GCLs used in waste containment applications.     

Spousal esteem.

This study tested the hypothesis that spousal esteem and disparagement are psychological states that track the costs and benefits of marriage to a particular person. Three separate data sources were used. First, 214 married participants reported on their personality, the esteem they held for their spouse, and issues the couple disagreed about. Second, participants provided information on their spouse's personality and behaviors their spouse performed that upset them. Third, couples were interviewed by two interviewers, who subsequently provided independent ratings of each participant's personality. Esteem held for a spouse negatively covaried with (a) spousal personality characteristics associated with cost-infliction, such as disagreeableness and emotional instability; (b) spousal sources of upset, such as physical abuse and inconsiderateness; and (c) frequency of conflict in six domains, including jealousy, affection, and money. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Predicting Solute Flux through a Clay Membrane Barrier

Measured solute flux breakthrough curves (FBCs) from column tests performed on a semipermeable clay membrane subjected to KCl solutions are compared with predicted FBCs using independently measured flow and transport properties. The predicted FBCs are based on three scenarios: (1) Advective–dispersive transport that neglects membrane behavior; (2) advective–dispersive transport that accounts for the concentration dependency of the effective salt-diffusion coefficient (Ds?) resulting from membrane behavior, referred to as partially coupled transport; and (3) fully coupled transport that includes both the explicit coupling terms (e.g., hyperfiltration, chemico-osmosis) associated with clay membrane behavior and the concentration dependency of Ds?. The FBCs predicted by fully coupled transport agree best with the measured FBCs. However, for the diffusion-controlled conditions of the column tests, the steady-state solute fluxes predicted by partially coupled transport are only 23–69% higher than the measured steady-state fluxes. The results imply that the advective–dispersive transport theory can be used to provide reasonably accurate, albeit somewhat conservative, estimates of steady-state solute flux through clays that behave as semipermeable membranes, provided diffusion is a significant, if not dominant, solute transport process and the concentration dependency of Ds? are taken into account.