scholarly journals Sources of individual variation in plasma testosterone levels

2007 ◽  
Vol 363 (1497) ◽  
pp. 1711-1723 ◽  
Author(s):  
Bart Kempenaers ◽  
Anne Peters ◽  
Katharina Foerster
Keyword(s):  
Individual Variation ◽  
Critical Role ◽  
Time Of Day ◽  
Integrative Approach ◽  
Plasma Testosterone ◽  
Extrinsic Factors ◽  
Honest Signalling ◽  
Large Variability ◽  
Trade Offs ◽  
Potential Sources

The steroid hormone testosterone (T) plays a central role in the regulation of breeding in males, because many physiological, morphological and behavioural traits related to reproduction are T dependent. Moreover, in many seasonally breeding vertebrates, male plasma T levels typically show a pronounced peak during the breeding season. While such population-level patterns are fairly well worked out, the sources and the implications of the large variability in individual T levels within the seasonal cycle remain surprisingly little understood. Understanding the potential sources of individual variation in T levels is important for behavioural and evolutionary ecologists, for at least two reasons. First, in ‘honest signalling’ theory, T is hypothesized to play a critical role as the assumed factor that enforces honesty of the expression of sexually selected quality indicators. Second, T is often considered a key mediator of central life-history trade-offs, such as investment in survival versus reproduction or in mating versus parental care. Here, we discuss the patterns of within- and between-individual variation in male plasma T levels in free-living populations of birds. We argue that it is unclear whether this variability mainly reflects differences in underlying individual quality (intrinsic factors such as genetic or maternal effects) or in the environment (extrinsic factors including time of day, individual territorial status and past experience). Research in avian behavioural endocrinology has mainly focused on the effects of extrinsic factors, while other sources of variance are often ignored. We suggest that studies that use an integrative approach and investigate the relative importance of all potential sources of variation are essential for the interpretation of data on individual plasma T levels.

DIURNAL VARIATION IN PLASMA TESTOSTERONE AND CORTISOL IN RHESUS MONKEYS LIVING IN SOCIAL GROUPS

1978 ◽  
Vol 76 (1) ◽  
pp. 67-74 ◽  
Author(s):  
R. M. ROSE ◽  
T. P. GORDON ◽  
I. S. BERNSTEIN
Keyword(s):  
Diurnal Variation ◽  
Individual Variation ◽  
Rhesus Monkeys ◽  
Plasma Cortisol ◽  
Social Groups ◽  
Time Of Day ◽  
Plasma Testosterone ◽  
Diurnal Changes ◽  
Considerable Individual Variation ◽  
Male Rhesus

SUMMARY Concentrations of cortisol and testosterone in the plasma of adult male rhesus monkeys living in social groups were determined during a 27-h period. Capture and venipuncture of experienced, conditioned animals did not lead to a fall in the concentration of testosterone in the plasma during the 90 min immediately after removal from the group. Both plasma cortisol and plasma testosterone concentrations showed a significant fall and rise in samples collected every 3 h during a 27-h period, even though there was considerable individual variation. During the autumn breeding season, animals showed higher concentrations of testosterone at both 10.00 and 22.00 h compared with those observed at the same times during the summer. Even though animals demonstrated significant diurnal changes, testosterone samples withdrawn at the same time of day (10.00 h) on consecutive days were significantly correlated with one another (r = 0·65, n = 27, P < 0·01), suggesting the usefulness of sampling once a day to study potential environmental influences on plasma testosterone concentrations.

scholarly journals Cubesat Antenna Analysis and Design: Are you using the right computational electromagnetic tool?

2021 ◽  
Vol 10 (2) ◽  
pp. 1-18
Author(s):  
I. Latachi ◽  
T. Rachidi ◽  
M. Karim
Keyword(s):  
Selection Process ◽  
Critical Role ◽  
Antenna System ◽  
Antenna Design ◽  
Design Processes ◽  
Analysis And Design ◽  
Trade Offs ◽  
Development Costs ◽  
Communication Links ◽  
The Right

Antenna systems play a critical role in establishing wireless communication links and sustaining remote sensing requirements for Cubesat applications. In addition to the usual antenna design requirements, Cubesat-based spacecrafts impose additional stringent constraints related to the on-board available space, power consumption and development costs. To develop optimal antenna prototypes while considering all these constraints and decrease trial and error related costs, computational electromagnetics (CEM) simulation tools are used. The accuracy of simulation results depends to a great extent on the choice of the appropriate CEM tool for the particular antenna problem to be analyzed; ergo, identifying and answering key questions about design objectives and requirements is necessary for informed decision-making throughout the selection and design processes. However, this could be quite challenging because of existing gaps both in the practitioners’ knowledge about different CEM tools capabilities, limitations, and design know-how. This is especially true for non-specialists such as students and academics involved in student driven Cubesat projects. Therefore, the rationale of this manuscript is to bridge those gaps and clarify some common misconception commonly encountered during the selection and design processes. In that regard, first, an overview of existing antenna configurations commonly used in Cubesat communications is provided. Next, antenna design general workflow is presented. Then, capabilities and limitations of different CEM solving methods are presented. After that, CEM software selection process trade-offs and possible sources of errors are discussed from a practical viewpoint. Finally, a case study of Masat-1 antenna system design is presented as practical example.

scholarly journals Molecular Determinants of μ-Conotoxin KIIIA Interaction with the Voltage-Gated Sodium Channel Nav1.7

2019 ◽  
Author(s):  
Ian H. Kimball ◽  
Phuong T. Nguyen ◽  
Baldomero M. Olivera ◽  
Jon T. Sack ◽  
Vladimir Yarov-Yarovoy
Keyword(s):  
Computational Modeling ◽  
Rational Design ◽  
Structural Model ◽  
Critical Role ◽  
Structural Data ◽  
Molecular Probes ◽  
Integrative Approach ◽  
In Silico Docking ◽  
Voltage Gated ◽  
Dynamics Simulations

AbstractThe voltage-gated sodium (Nav) channel subtype Nav1.7 plays a critical role in pain signaling, making it an important drug target. Here we studied the molecular interactions between μ-conotoxin KIIIA (KIIIA) and the human Nav1.7 channel (hNav1.7). We developed a structural model of hNav1.7 using Rosetta computational modeling and performed in silico docking of KIIIA using RosettaDock to predict residues forming specific pairwise contacts between KIIIA and hNav1.7. We experimentally validated these contacts using mutant cycle analysis. Comparison between our KIIIA-hNav1.7 model and the recently published cryo-EM structure of KIIIA-hNav1.2 revealed key similarities and differences between channel subtypes with potential implications for the molecular mechanism of toxin block. Our integrative approach, combining structural data with computational modeling, experimental validation, and molecular dynamics simulations will be useful for engineering molecular probes to study Nav channel function, and for rational design of novel biologics targeting specific Nav channels.

scholarly journals The neurogenomic transition from territory establishment to parenting in a territorial female songbird

BMC Genomics ◽  
2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Alexandra B. Bentz ◽  
Douglas B. Rusch ◽  
Aaron Buechlein ◽  
Kimberly A. Rosvall
Keyword(s):  
Breeding Season ◽  
Neural Plasticity ◽  
Behavioral Plasticity ◽  
Critical Role ◽  
Regulatory Pathways ◽  
Expression Of Genes ◽  
Trade Offs ◽  
Glucocorticoid Signaling ◽  
Seasonally Breeding ◽  
The Brain

Abstract Background The brain plays a critical role in upstream regulation of processes central to mating effort, parental effort, and self-maintenance. For seasonally breeding animals, the brain is likely mediating trade-offs among these processes within a short breeding season, yet research thus far has only explored neurogenomic changes from non-breeding to breeding states or select pathways (e.g., steroids) in male and/or lab-reared animals. Here, we use RNA-seq to explore neural plasticity in three behaviorally relevant neural tissues (ventromedial telencephalon [VmT], hypothalamus [HYPO], and hindbrain [HB]), comparing free-living female tree swallows (Tachycineta bicolor) as they shift from territory establishment to incubation. We additionally highlight changes in aggression-related genes to explore the potential for a neurogenomic shift in the mechanisms regulating aggression, a critical behavior both in establishing and maintaining a territory and in defense of offspring. Results HB had few differentially expressed genes, but VmT and HYPO had hundreds. In particular, VmT had higher expression of genes related to neuroplasticity and processes beneficial for competition during territory establishment, but down-regulated immune processes. HYPO showed signs of high neuroplasticity during incubation, and a decreased potential for glucocorticoid signaling. Expression of aggression-related genes also shifted from steroidal to non-steroidal pathways across the breeding season. Conclusions These patterns suggest trade-offs between enhanced activity and immunity in the VmT and between stress responsiveness and parental care in the HYPO, along with a potential shift in the mechanisms regulating aggression. Collectively, these data highlight important gene regulatory pathways that may underlie behavioral plasticity in females.

scholarly journals Braiding topology and the energy landscape of chromosome organization proteins

2019 ◽  
Vol 117 (3) ◽  
pp. 1468-1477 ◽  
Author(s):  
Dana Krepel ◽  
Aram Davtyan ◽  
Nicholas P. Schafer ◽  
Peter G. Wolynes ◽  
José N. Onuchic
Keyword(s):  
Structural Information ◽  
Protein Complexes ◽  
Energy Landscape ◽  
Critical Role ◽  
Coiled Coil ◽  
Structural Data ◽  
Atomic Scale ◽  
Integrative Approach ◽  
Chromosome Organization ◽  
Conformational Ensemble

Assemblies of structural maintenance of chromosomes (SMC) proteins and kleisin subunits are essential to chromosome organization and segregation across all kingdoms of life. While structural data exist for parts of the SMC−kleisin complexes, complete structures of the entire complexes have yet to be determined, making mechanistic studies difficult. Using an integrative approach that combines crystallographic structural information about the globular subdomains, along with coevolutionary information and an energy landscape optimized force field (AWSEM), we predict atomic-scale structures for several tripartite SMC−kleisin complexes, including prokaryotic condensin, eukaryotic cohesin, and eukaryotic condensin. The molecular dynamics simulations of the SMC−kleisin protein complexes suggest that these complexes exist as a broad conformational ensemble that is made up of different topological isomers. The simulations suggest a critical role for the SMC coiled-coil regions, where the coils intertwine with various linking numbers. The twist and writhe of these braided coils are coupled with the motion of the SMC head domains, suggesting that the complexes may function as topological motors. Opening, closing, and translation along the DNA of the SMC−kleisin protein complexes would allow these motors to couple to the topology of DNA when DNA is entwined with the braided coils.

Characterization of Exotic Material Heat Sinks for Laser Diode Arrays

2005 ◽  
Vol 883 ◽  
Author(s):  
Edward.F. Stephens
Keyword(s):  
Laser Diode ◽  
High Performance ◽  
Critical Role ◽  
Cost Effective ◽  
Heat Sinks ◽  
High Peak Power ◽  
Low Duty Cycle ◽  
Trade Offs ◽  
Duty Cycles ◽  
Laser Diode Arrays

AbstractLow duty cycle, high peak power, conductively cooled laser diode arrays have been manufactured for several years by a number of different vendors. Typically these packages have been limited to a few percent duty cycles due to thermal problems that develop in tight bar pitch arrays at higher duty cycles. Traditionally these packages are made from some combination of copper and BeO or Tungsten/copper and BeO. Trade-offs between thermal conductivity and CTE matching are always made when manufacturing these devices. In addition, the manufacturability of the heat sinks plays a critical role in creating a cost effective, high performance solution. In this discussion we examine several different exotic materials that have been manufactured and tested as heat sinks for laser diode arrays.

scholarly journals Integrating Stakeholder Views and System Dynamics to Assess the Water–Energy–Food Nexus in Andalusia

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3172
Author(s):  
Adrián González-Rosell ◽  
Maria Blanco ◽  
Imen Arfa
Keyword(s):  
System Dynamics ◽  
Climate Scenario ◽  
System Dynamics Model ◽  
Dynamics Model ◽  
Close Link ◽  
Large Variability ◽  
Trade Offs ◽  
Irrigation Water Use ◽  
Sustainability Strategies ◽  
As Effects

A nexus approach can support the transition to sustainability by addressing trade-offs and pursuing synergies to improve water, energy, and food security. In this paper, a participatory system dynamics model was developed to identify and assess the key interlinkages between water, food, and energy in Andalusia (Spain). A panel of relevant stakeholders contributed to all stages of the model’s development. Further, by calibrating the model to CAPRI-Water projections until 2050, the evolution of the system under a plausible climate scenario, as well as effects of water prices changes, was evaluated. The results revealed a close link between water cost, irrigation water use, energy consumption, and the economic development of agriculture in the region. Large variability was observed in the effects of water pricing policies across crops. This paper concludes that a participatory system dynamics model can help in understanding the nexus synergies and can support the design of more coherent sustainability strategies in the region.

scholarly journals Factors affecting individual variation in nest-defense intensity in colonially breeding Black-tailed Gulls (Larus crassirostris)

2011 ◽  
Vol 89 (10) ◽  
pp. 938-944 ◽  
Author(s):  
Kentaro Kazama ◽  
Yasuaki Niizuma ◽  
Kentaro Q. Sakamoto ◽  
Yutaka Watanuki
Keyword(s):  
Individual Variation ◽  
Physiological State ◽  
Breeding Birds ◽  
Egg Laying ◽  
Nest Defense ◽  
Laying Date ◽  
Plasma Testosterone ◽  
Factors Affecting ◽  
Corvus Macrorhynchos ◽  
Males And Females

The physiological state of parent birds combined with the value of their clutch may affect the intensity of their nest defense. In colonially breeding birds, nest-defense intensity may also be affected by the behavior of neighbors. We investigated individual variation in the nest-defense intensity among colonial Black-tailed Gulls ( Larus crassirostris Vieillot, 1818) over 2 years. Only 30%–40% of males attacked a decoy of an egg predator (Large-billed Crow ( Corvus macrorhynchos Wagler, 1827)), and the other males and females rarely attacked. Males attacking the decoy had higher levels of plasma testosterone than males that did not attack. Each male’s, but not female’s, nest-defense intensity was consistent throughout the incubation period and also across years. The intensity was not related to egg-laying date, clutch size, or age of offspring. The intensity was likely to be higher when individuals had one or more neighbors, representing higher nest-defense intensity in the year where gulls had larger number of adjacent neighboring nests (5.23 nests), but this trend was not observed in the year where they had smaller number of the neighboring nests (3.73 nests). Thus, in addition to testosterone levels, behavior of neighbors also influences the nest-defense intensity.

scholarly journals Plain faces are more expressive: comparative study of facial colour, mobility and musculature in primates

2014 ◽  
Vol 10 (5) ◽  
pp. 20140275 ◽  
Author(s):  
Sharlene E. Santana ◽  
Seth D. Dobson ◽  
Rui Diogo
Keyword(s):  
Comparative Study ◽  
Social Interactions ◽  
Facial Expressions ◽  
Phenotypic Traits ◽  
Facial Features ◽  
Facial Nucleus ◽  
Extrinsic Factors ◽  
Trade Offs ◽  
Complex Relationships ◽  
Colour Patterns

Facial colour patterns and facial expressions are among the most important phenotypic traits that primates use during social interactions. While colour patterns provide information about the sender's identity, expressions can communicate its behavioural intentions. Extrinsic factors, including social group size, have shaped the evolution of facial coloration and mobility, but intrinsic relationships and trade-offs likely operate in their evolution as well. We hypothesize that complex facial colour patterning could reduce how salient facial expressions appear to a receiver, and thus species with highly expressive faces would have evolved uniformly coloured faces. We test this hypothesis through a phylogenetic comparative study, and explore the underlying morphological factors of facial mobility. Supporting our hypothesis, we find that species with highly expressive faces have plain facial colour patterns. The number of facial muscles does not predict facial mobility; instead, species that are larger and have a larger facial nucleus have more expressive faces. This highlights a potential trade-off between facial mobility and colour patterning in primates and reveals complex relationships between facial features during primate evolution.

Managing conflict in online debate communities

First Monday ◽  
2019 ◽  
Author(s):  
Jordan Beck ◽  
Bikalpa Neupane ◽  
John M. Carroll
Keyword(s):  
Conflict Management ◽  
Production System ◽  
Interface Design ◽  
Participant Observation ◽  
Critical Role ◽  
Common Source ◽  
Peer Production ◽  
Beliefs And Values ◽  
Potential Sources ◽  
Online Debate

Kialo is a novel peer production system focused on pro/con debate construction. Distributed moderator teams vet and accept claims submitted by writers. Moderators also edit and refactor debates as they grow. Thus, moderators play a critical role in cultivating and maintaining debates. Conflict between moderators is typical. It is a feature of argumentation and debate. However, not all conflict is productive. Conflict between moderators can undermine collaboration (by distracting from the task of managing debates) and drive attrition (by discouraging participation on the site altogether). Based on a ten-month participant observation on Kialo, we identify a common source of conflict between moderators: adversarial beliefs and values. Moderators are not neutral participants on Kialo. They take positions on debate topics. We suggest foregrounding these positions, which are potential sources of conflict, through interface design as a scalable way to facilitate conflict management.

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