My Home Is Your Castle: Roost Making Is Sexually Selected in the Bat Lophostoma silvicolum

Shelters are important for the survival and reproduction of many animals and this is particularly true for bats. Depending on the future use and effect of shelters on the fitness of individuals, not all members of a group of animals may contribute equally to shelter making. Thus, knowledge about the identity of shelter-making individuals may teach us much about the social system and mating strategy of species. To exemplify this, we review what is known about the roost-making behavior and the social system of Lophostoma silvicolum, a neotropical bat that excavates roost cavities in active arboreal termite nests. Roosts in termite nests are highly beneficial for the bats because they offer improved microclimate and possibly are responsible for the lower parasite loads of L. silvicolum in comparison to bat species using other, more common, roost types. Examination of observational field data in combination with genetic analyses shows that roost cavities excavated by single males subsequently serve as maternity roosts for females and that this improves reproductive success of the male who excavated the roost. This suggests that roosts in termite nests serve as an extended male phenotype and roost making is a sexually selected behavior. Roost-making behavior is tightly linked to the species' social organization (single-male-multifemale associations that stay together year-round) and mating system (resource-defense polygyny). The case study of L. silvicolum shows that it is important to learn more about the implications of shelter making in bats and other animals from ongoing and future studies. However, differences in costs and benefits for each group member must be carefully evaluated before drawing conclusions about social systems and mating strategies in order to contribute to our current knowledge about the evolution of sociality in mammal

Sexual Segregation and Flexible Mating Patterns in Temperate Bats

Social structure evolves from a trade-off between the costs and benefits of group-living, which are in turn dependent upon the distribution of key resources such as food and shelter. Males and females, or juveniles and adults, may have different priorities when selecting habitat due to differences in physiological or behavioural imperatives, leading to complex patterns in group composition. We studied social structure and mating behaviour in the insectivorous bat Myotis daubentonii along an altitudinal gradient, combining field studies with molecular genetics. With increasing altitude the proportion of males in summer roosts increased and only males were present in the highest roosts. With increasing altitude environmental temperature decreased, nightly variation in temperature increased, and bat foraging activity decreased, supporting the hypothesis that the harsher, high elevation sites cannot support breeding females. We found that offspring in female-dominated lowland roosts had a very high probability of being fathered by bats caught during autumn swarming at hibernation sites, in contrast to those in intermediate roosts, which had a high probability of being fathered by males sharing the nursery roost with the females. Whilst females normally appear to exclude males from nursery colonies, for those in marginal habitats, one explanation for the presence of males is that the thermoregulatory benefits to the females may outweigh disadvantages, such as competition for food, and give some males an opportunity to increase their breeding success. We suggest that the environment, and its effects on resource distribution, thus determine social structure, which in turn determines the mating pattern that has evolved

Cytotoxic Effect of Ethanol Extract of Convolvulus arvensis L (Convolvulaceae) on Lymphoblastic Leukemia Jurkat Cells

Purpose: To evaluate the cytotoxic effect of ethanol extract of aerial parts of Convolvulus arvensis against lymphoblastic leukemia, Jurkat cells.Methods: The aerial parts of C. arvensis were collected, identified, powdered and soaked in ethanol. The extract was filtered and evaporated, and the residue assessed for cytotoxic activity in Jurkat cell line. The cells were exposed to different concentrations (10, 25, 50, 75 and 100 μg/mL) of the extract to determine cell viability, cell proliferation, apoptosis using Trypan blue exclusion assay, 3-(4,5- dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay and fluorescent activated cell sorter (FACS) analysis, respectively.Results: Trypan blue exclusion assay and MTS assay results indicate that the ethanol extract decreased the number of living cells in a concentration-dependent fashion. The results of FACS analysis showed that the lowest concentration of the extract (10 μg/mL) was most effective for the induction of apoptosis as it induced maximum apoptosis (85.34 %) and the highest concentration (100 μg/mL) was less effective as it induced less apoptosis (53.70 %) in Jurkat cells (p < 0.05).Conclusion: The ethanol extract of C. arvensis has significant cytotoxic activity against the selected cancer cell line. Furthermore, apoptotic effect was more prominent at lower doses and necrosis at higher doses of the extract.Keywords: Convolvulus arvensis; (MTS) 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4- sulfophenyl)-2H-tetrazolium assay; Trypan blue exclusion assay, Apoptosis, Necrosi

An exploration of individual personality types in software development

Previous research - using conventional psychometric questionnaires - has highlighted the importance of aligning compatible personality types in software development teams. However, there does not exist a dedicated, robust questionnaire instrument for revealing the pertinent personality types for software development practitioners. This study analyzes the validity and reliability of a 70-item (context dependent) personality-profiling questionnaire particularly developed to assess personality types of software practitioners. A systematic process of validation, using an iterative approach to questionnaire development, was employed. The questions were developed both with a qualitative analysis of interview data, and based on the opinions of expert reviewers who revised the items through a set of examination. To investigate how stable the questions and reproducible the results, we measured test-retest reliability of the instrument, yielding satisfactory results. The present study provided evidence for the construct validity of the instrument. Ultimately, an initial comparison of the results delivered by the instrument demonstrated positive correlations with the findings acquired with well- known personality assessment instrument, i.e. the big five personality questionnaire

Cooking Surface Temperatures, Steak Thickness, and Quality Grade Effects on Volatile Aroma Compounds

Volatile aroma compounds were evaluated in USDA Top Choice and Select beef top loin steaks cut 1.3 cm (THIN) or 3.8 cm (THICK) and cooked on a commercial flat top grill at 177°C (LOW) or 232°C (HIGH) grill surface temperature. Gas chromatography/mass spectrophotometry was used to evaluate volatile aroma compounds. USDA Select steaks had more 2-octene and less trimethyl pyrazine in (P < 0.05) THIN steaks than THICK steaks, whereas Choice was unaffected by steak thickness (P > 0.05). Benzene acetaldehyde was higher and 4-hydroxybenzoic acid was higher in Select LOW grill temperatures compared with Select HIGH grill temperatures, whereas 5-methyl-2-furan carboxaldehyde was only present in Choice HIGH grill temperatures (P < 0.05). Two acids, 3 alcohols, 1 aldehyde, 1 alkane, and 1 ketone volatile aroma compound were higher (P < 0.05) for LOW compared with HIGH. Conversely, 5 alcohols, 2 aldehydes, 2 alkanes, all 4 furans, 6 ketones, 4 pyrazines, along with 1H-indole, 2 pyrroles, 2 pyridines, and 1 benzene aroma compound were higher (P < 0.05) in HIGH compared with LOW. Additionally, 1 alcohol, 2 aldehydes, 1 ketone, 1 sulfur-containing, and 6 other volatile compounds were lower, whereas 1 acid, 1 alcohol, 1 aldehyde, 2 furans, 1 ketone, 3 pyrazines, 1 sulfur-containing, and 1 other volatile compound were higher in the THIN compared with THICK. Some aroma compounds such as 2-butanone, 4-methyl-2-pentanone, 1-ethyl-1H-pyrrole, 1-methyl-1H-pyrrole, and 2-methyl-pyridine were only present in THICK cooked HIGH (P < 0.05). Steak thickness and grill temperature are important factors to consider in the development of positive Maillard reaction products. Key findings are that high grill temperatures and/or thick steaks with longer grilling times are required for the development of key Maillard reaction products and many Maillard reaction products were only found in the most severe high-temperature, long-time grilling scenarios

Descriptive Beef Flavor Attributes and Consumer Acceptance Relationships for Heavy Beef Eaters

Differences in beef flavor attributes were created using beef cuts (Choice M. gluteus medius (GM) steaks; Choice M. biceps femoris (BF) roasts; Select BF roasts; Choice M. longissimus lumborum (LM) steaks, and high pH LM steaks), cooking method, and internal cook temperature endpoint (END). Steaks were cooked to 58°C and 80°C END utilizing either a George Foreman clamshell grill (GF) or a flat top electric food-service grill (GRILL). Roasts were cooked at low temperatures using a Crock-Pot (CP) cooking to 58°C and 80°C END. Thirty-seven flavor descriptive attributes were evaluated by an expert, trained descriptive beef flavor panel. Heavy beef eaters were recruited in Houston, TX; Olathe, KS; Philadelphia, PA; and Portland, OR. Consumers evaluated overall, flavor, beef flavor, and grill flavor liking using 9-point hedonic scales and beef flavor, grill flavor and off-flavor intensity using 9-point intensity scales. Steaks and roasts differed in descriptive and consumer attributes (P < 0.05). Treatments with higher levels of fat-like, salt, beef identity, and brown/roasted flavor attributes had higher consumer liking ratings (Choice LM or GM GRILL steaks cooked to 58°C or 80°C and Choice GM GRILL steaks cooked to 80°C). Select and Choice BF CP roasts cooked to 58°C or 80°C, Choice GM GF steaks cooked to 80°C, and high pH LM GF steaks cooked to 80°C had the lowest consumer liking scores and higher levels of warmed-over flavor, cardboardy, and liver-like flavor attributes. Heavy beef consumers segmented into 4 classes. Class 4 consumers liked beef regardless of treatment, whereas Class 3 consumers were discerning. Heavy beef eaters discerned differences in beef flavor attributes, and beef flavor was a driver of consumer liking

Untargeted Metabolomics for Beef Flavor Beyond Fat in Ground Beef With Different Lean Sources and Different Fat Content From a Common Fat Source

To explore the effects of lean source on the flavor of ground beef patties, beef inside rounds (n=9) were procured from each of the following treatment groups: commodity upper two-thirds choice (HC; USDA modest and higher marbling), heart-healthy-branded (HEART), natural grass-fed (NATURAL), and commodity USDA Select (SELECT) beef. Rounds from each source were ground and supplemented with commercially sourced, pre-ground commodity fat trim to form treatment batches containing10% or 20% total fat. Batches were then fine-ground and formed into 113.5-g patties. Patties were vacuum packaged and frozen until analyzed. Trained sensory panel, fatty acid profile, volatile compound composition, and metabolomic features subsequently were analyzed. Lean source had no impact (P>0.05) on any major trained sensory traits, but patties with 20% fat had higher (P<0.05) fat-like, buttery, and juiciness scores. Patties made with HEART lean had the highest (P<0.05) monounsaturated fatty acids, and those from SELECT lean had the lowest. Those patties made with NATURAL lean and 20% fat tended (0.05<P<0.10) to have higher volatile concentrations of alcohol, aldehyde, ketones, and especially terpenoid compounds. Using discriminate analysis, metabolites (n=64 metabolites) from raw samples were accurately segregated by lean source only, while the cooked patties showed that the 138 metabolites were able to discriminate lean source for HC, HEART, and NATURAL within both 10% and 20% fat treatments. Patties made with SELECT lean clustered by themselves and generally had the opposite reaction to metabolite concentration as the other lean sources. Overall, while lean sources did not impact flavor, patties with different lean sources impacted the fatty acid content, volatile aroma compounds, and metabolite distribution in ground beef patties. Metabolomics may be another valuable tool to help describe meat quality, and it could be used to determine these traits in lean prior to sensory testing

Steak Thickness, Cook Surface Temperature and Quality Grade Affected Top Loin Steak Consumer and Descriptive Sensory Attributes

Beef flavor attributes of USDA Top Choice and Select beef top loin steaks were evaluated that differed in thickness (1.3 or 3.8 cm) and grill surface temperature (177 or 232°C) when cooked on a commercial flat top grill. A trained descriptive attribute panel and consumer sensory panels were used to evaluate steak flavor and texture. As thickness and temperature increased, beef identity and brown/roasted flavor aromatics increased (P < 0.05). Steaks cooked at 232°C and cut 3.8-cm thick had the highest (P < 0.05) levels of burnt flavor and bitter basic tastes. Thicker steaks cooked at 177°C had more intense umami basic taste and beef identity (P < 0.05). Steaks cut 1.3 cm had lower levels of beef identity and brown/roasted flavor aromatics and the thin cut steaks cooked at 177°C had more sour basic taste (P < 0.05). Consumers rated 232°C, 3.8 cm steaks lowest (P < 0.05) for overall, beef flavor, overall flavor, and grilled flavor liking; whereas, the 177°C, 3.8 cm steaks were highest (P < 0.05) in beef flavor liking. Beef identity, brown/roasted, bloody/serumy, fat-like, umami, sweet, salty, overall sweet, overall tenderness, and muscle fiber tenderness were positive attributes, and metallic, bitter, and burnt were negative attributes in predicting consumer overall liking. Thick steaks cooked at low temperatures or thin steaks cooked at high temperatures resulted in more positive sensory panel traits and consumer liking scores

Thermophysical Properties of Beef Steaks of Varying Thicknesses Cooked With Low and High Grill Surface Temperatures

The objective of this study was to determine the thermodynamic and physical properties of beef strip loin steaks of varying thicknesses and USDA quality grades cooked with high and low grill surface temperatures. Thermal characteristics described by changes in the denaturation temperature (between 55°C – 60°C) and enthalpies of protein denaturation (70°C – 75°C) both differed (P = 0.031 and P = 0.001, respectively) among thick steaks, with thick steaks cooked on a high grill surface temperature having a lower denaturation temperature and enthalpy compared with thick steaks cooked on a low grill surface temperature. No differences (P &gt; 0.05) were observed among thin steaks for denaturation temperature or enthalpy. The elastic behaviors of the surface and center of the steaks were analyzed to determine how the microstructure of the beef responded to applied stress. The elastic behavior of steak centers was influenced in a three-way interaction (P = 0.029) between quality grade, steak thickness, and grill surface temperature. The elastic behavior of the surface of steaks was influenced by the interaction of quality grade and steak thickness (P = 0.031). These interactions, along with the differences in the thermal characteristic of proteins, suggest that the microstructure of steaks was affected by each cooking treatment group. Hardness, resilience, and chewiness were each influenced by a three-way interaction (P = 0.023; 0.014; and 0.030; respectively). Thin steaks possessed greater cohesiveness (P = 0.038) and shear force ( P = 0.007) values. Meanwhile, thin steaks exhibited lower springiness (P = 0.002). The measured alterations in thermal and physical proper- ties in the beef steaks suggest that the composition, thickness, and cooking regiments impact the microstructure of beef, and this was ultimately confirmed through textural measurements. The results of this research can be used in the design of cooking processes that match beef characteristics