On the Field Equations of Kaluza's Theory

The field equations of the original Kaluza's theory are analyzed and it is shown that they lead to modification of Einstein's equations. The appearing extra energy-momentum tensor is studied and an example is given where this extra energy-momentum tensor is shown to allow four-dimensional Schwarzschild geometry to accommodate electrostatics. Such deviation from Reissner-Nordstrom geometry can account for the interpretation of Schwarzschild geometry as resulting not from mass only, but from the combined effects of mass and electric charge, even electric charge alone.Comment: 14 pages, two sections added and title changed. To appear in Physics Letters

Tennis grunts communicate acoustic cues to sex and contest outcome

Despite their ubiquity in human behaviour, the communicative functions of nonverbal vocalisations remain poorly understood. Here, we analysed the acoustic structure of tennis grunts, nonverbal vocalisations produced in a competitive context. We predicted that tennis grunts convey information about vocalizer and context, similar to nonhuman vocal displays. Specifically, we tested whether the fundamental frequency (F0) of tennis grunts conveys static cues to a player’s sex, height, weight, and age, and covaries dynamically with tennis shot type (a proxy of body posture) and the progress and outcome of male and female professional tennis contests. We also performed playback experiments (using natural and resynthesised stimuli) to assess the perceptual relevance of tennis grunts. The F0 of tennis grunts predicted player sex, but not age or body size. Serve grunts had higher F0 than forehand and backhand grunts, grunts produced later in contests had higher F0 than those produced earlier, and grunts produced during contests that players won had a lower F0 than those produced during lost contests. This difference in F0 between losses and wins emerged early in matches, and did not change in magnitude as the match progressed, suggesting a possible role of physiological and/or psychological factors manifesting early or even before matches. Playbacks revealed that listeners use grunt F0 to infer sex and contest outcome. These findings indicate that tennis grunts communicate information about both vocalizer and contest, consistent with nonhuman mammal vocalisations

Clutch Frequency Affects the Offspring Size-Number Trade-Off in Lizards

Background: Studies of lizards have shown that offspring size cannot be altered by manipulating clutch size in species with a high clutch frequency. This raises a question of whether clutch frequency has a key role in influencing the offspring sizenumber trade-off in lizards. Methodology/Principal Findings: To test the hypothesis that females reproducing more frequently are less likely to tradeoff offspring size against offspring number, we applied the follicle ablation technique to female Eremias argus (Lacertidae) from Handan (HD) and Gonghe (GH), the two populations that differ in clutch frequency. Follicle ablation resulted in enlargement of egg size in GH females, but not in HD females. GH females switched from producing a larger number of smaller eggs in the first clutch to a smaller number of larger eggs in the second clutch; HD females showed a similar pattern of seasonal shifts in egg size, but kept clutch size constant between the first two clutches. Thus, the egg sizenumber trade-off was evident in GH females, but not in HD females. Conclusions/Significance: As HD females (mean = 3.1 clutches per year) reproduce more frequently than do GH females (mean = 1.6 clutches per year), our data therefore validate the hypothesis tested. Our data also provide an inference that maximization of maternal fitness could be achieved in females by diverting a large enough, rather than a higher-than-usual

Regional differences in lumbar spinal posture and the influence of low back pain

<p>Abstract</p> <p>Background</p> <p>Spinal posture is commonly a focus in the assessment and clinical management of low back pain (LBP) patients. However, the link between spinal posture and LBP is not fully understood. Recent evidence suggests that considering regional, rather than total lumbar spine posture is important. The purpose of this study was to determine; if there are regional differences in habitual lumbar spine posture and movement, and if these findings are influenced by LBP.</p> <p>Methods</p> <p>One hundred and seventy female undergraduate nursing students, with and without LBP, participated in this cross-sectional study. Lower lumbar (LLx), Upper lumbar (ULx) and total lumbar (TLx) spine angles were measured using an electromagnetic tracking system in static postures and across a range of functional tasks.</p> <p>Results</p> <p>Regional differences in lumbar posture and movement were found. Mean LLx posture did not correlate with ULx posture in sitting (r = 0.036, p = 0.638), but showed a moderate inverse correlation with ULx posture in usual standing (r = -0.505, p < 0.001). Regional differences in range of motion from reference postures in sitting and standing were evident. BMI accounted for regional differences found in all sitting and some standing measures. LBP was not associated with differences in regional lumbar spine angles or range of motion, with the exception of maximal backward bending range of motion (F = 5.18, p = 0.007).</p> <p>Conclusion</p> <p>This study supports the concept of regional differences within the lumbar spine during common postures and movements. Global lumbar spine kinematics do not reflect regional lumbar spine kinematics, which has implications for interpretation of measures of spinal posture, motion and loading. BMI influenced regional lumbar posture and movement, possibly representing adaptation due to load.</p

Causes and consequences of variable testosterone in two Fairywren species

Sex steroids like testosterone can mediate multiple traits underlying alternate phenotypes. For instance, seasonal increases in testosterone can facilitate molt into ornamental plumage and expression of territorial and sexual behavior in many male birds. In chapter 2 I capitalize on naturally occurring wildfires prior to the breeding season to test whether male Red-backed Fairywrens (Malurus melanocephalus) are plastic in their timing of testosterone-mediated production of ornamentation. I found that suppressed testosterone circulation inhibits, or at least greatly delays acquisition of ornamentation. Whether mechanisms of ornament production are shared among sexes of closely related species is poorly understood and is explored in chapter 3. I use a testosterone supplementation experiment to determine if elevated testosterone causes unornamented female White-shouldered Fairywrens (Malurus alboscapulatus) to molt ornamental plumage and express elevated territoriality consistent with the naturally occurring ornamented female phenotype. I found that testosterone-implanted females develop partial ornamentation followed by enhanced territoriality. Finally, to test among the leading hypotheses about what causes rapid elevations of testosterone circulation, I use a combination of correlative and experimental approaches in male White-shouldered Fairywrens. I first show that males of the unornamented female lorentzi subspecies circulate greater mean testosterone and score higher in four of five metrics for social interaction relative to males of the ornamented female moretoni subspecies. Then I use an experiment to test which social interactions cause elevated testosterone and find that males captured while actively courting females have significantly greater plasma testosterone than males captured during active territory defense or males that were flushed into nets absent a social stimulus. Taken together, I find that both the physical and social environment contribute to variation in testosterone circulation, thus causing downstream effects to ornamentation and associated behavior

Enbody_Behavioral_Ecology_2018_Rscript_Testosterone_Data

An R markdown file (easily opened in RStudio) for analyzing raw testosterone data (in Enbody_WSFW_androgens.csv). Requires local installation of several R packages

Enbody_Behavioral_Ecology_2018_Testosterone_Raw_Data

Raw testosterone data (plasma testosterone levels) to be processed by Androgens_Comparative.Rmd

Data from: Female ornamentation is associated with elevated aggression and testosterone in a tropical songbird

In males, testosterone plays a key role in ornament production and linking ornamentation with reproductive behaviors and other traits to produce an integrated phenotype. Less is known about whether females couple testosterone, ornamentation, and aggressive behaviors to achieve female-specific combinations of traits. Ornamentation in females may be the result of correlated expression with male ornamentation, or female traits could arise as the result of sex specific selection pressures. Resolving between these alternatives is necessary to understand the degree to which selection acts on female traits. The White-shouldered Fairywren (Malurus alboscapulatus) provides a useful context to address these questions because populations vary in degree of female ornamentation, a derived trait, whereas male ornamentation is constant across both populations. We found that ornamented females have higher levels of circulating testosterone and respond more aggressively to experimental territorial intrusions than do unornamented females. These findings are consistent with the idea that, among female White-shouldered Fairywrens, testosterone may mechanistically link plumage and behavioral traits to produce an integrated competitive phenotype, as has been reported for males of closely related species. In contrast, circulating testosterone in males did not differ significantly between populations. More broadly, our findings are consistent with ongoing selection on the mechanisms underlying female ornaments, likely via social selection

Enbody_RStudio_Project

This zip file contains the R Studio project that holds all the scripts and data that are also separately uploaded here on Dryad. You can just open this and run it out of the box, without downloading the other files. However, you will still need to install the R packages that are loaded

Enbody_Behavioral_Ecology_2018_RScript_Experimental_Response_Mount_Data

An R Markdown file (easily opened in R studio) for analyzing response to simulated territorial intrusions by White-shouldered Fairywrens (data in Enbody_WSFW_mount_responses_revised_renamed.csv and binresp2.csv)