Radiotelemetry Of Heart Rates From Free-Ranging Gulls

A lightweight radiotelemetry system with a range of 80 km was used to monitor heart rate from free-ranging Herring Gulls on flights of up to 20 km. Heart rate varied from 130 beats/min in a resting bird to 625 beats/min for sustained flight. Soaring birds showed rates similar to those of birds sitting quietly on the ground. Simultaneous records of telemetered heart rate and intraspecific conflict on the nesting island revealed that cardiac acceleration preceded overt visual communication. Intensely aggressive behavior was accompanied by heart rates approaching those of sustained flight. Heart rate as a measure of metabolic cost indicates that the gull\u27s behavioral adaptations for long-distance flight, food location and intraspecific communication result in major energy savings

Electron Microscopy of Endothelial Cell - Biopolymer Interaction

Vascular endothelial cells form a natural antithrombogenic lining on all blood vessels. Replacement or bypass of small diameter blood vessels with artificial polymeric grafts has not been clinically acceptable due to the thrombogenic nature of polymeric material. One approach to improving the patency of vascular prosthetic devices has been the establishment of endothelial monolayers on the blood flow surface using the technique known as seeding. Scanning electron microscopy has been a major tool in evaluating the interaction of endothelial cells with polymeric surfaces resulting in a basic understanding of forces and structures regulating endothelium-polymer interactions. In-vitro and in-vivo studies have established the feasibility of using endothelial cell seeding technology in human clinical trials. This tutorial describes the development of endothelial cell seeding technology and illustrates how scanning electron microscopic evaluations have furthered our understanding of endothelial cell-polymer interactions

Policies for improving the competitiveness of smallholder livestock producers in the central corridor of West Africa: implications for trade and regional integration

Cet ouvrage rassemble les comptes-rendus d'un atelier d'Abidjan sur le theme "Quelles politiques pour ameliorer la competitivite des petits eleveurs dans la corridor central de l'Afrique de l'ouest: implications pour le commerce et l'integration regionale". L'objectif de I'atelier s'inscrivait dans le cadre de la lutte contre la pauvrete engagee par les Etats et les gouvernements de la sous-region, en collaboration avec les instituts de recherche et les bailleurs de fonds. Il visait de facon specifique a identifier les contraintes qui pesent sur les petits eleveurs de la sous-region et qui les empechent d'acceder au marche des produits animaux marche en pleine expansion, en raison notamment d'une pression de la demande, due a I'accroissement demographique et au phenomene d'urbanisation. Une des originalites de 1'atelier etait la participation effective des eleveurs et des marchands de betail, venus aussi bien des pays saheliens producteurs que des pays cotiers importateurs. A cette presence d'operateurs economiques s'ajoutait celle de scientifiques et de chercheurs, ainsi que la presence de decideurs et de bailleurs de fonds. Cet interface a permis une fois de plus d'identifier les entraves au marche regional du betail et de la viande surtout pour les petits producteurs, mais egalement de repertorier les defis et opportunites du secteur, dans le contexte de la mondialisation des echanges. Les contributions des participants ont essentiellement porte sur la situation des differentes filieres animales dans les pays : production, sante animale, commercialisation, ainsi que sur 1'environnement institutionnel et macroeconomique. La complementarite naturelle des pays en matiere de produits animaux a ete mise en evidence, de meme que lee entraves a une valorisation systematique du betail comme facteur privilegie d'integration economique. Les presentations ont ete suivies de discussions en commissions de travail sur les aspects production et commercialisation. Les principales conclusions et recommandations de 1'atelier ont porte sur la necessite de reorganiser lee operateurs a tous les niveaux, de mettre en place des structures de financement adaptees, de regionaliser et d'harmoniser les programmes de sante animale et lee politiques sectorielles. Enfin les participants ont vivement souhaite que 1'atelier debouche sur un programme regional de developpement des productions animales qui valorise les avantages comparatifs des pays, tout en assurant aux petits producteurs un meilleur acces au marche

Multiple prebiotic metals mediate translation.

Today, Mg2+ is an essential cofactor with diverse structural and functional roles in life's oldest macromolecular machine, the translation system. We tested whether ancient Earth conditions (low O2, high Fe2+, and high Mn2+) can revert the ribosome to a functional ancestral state. First, SHAPE (selective 2'-hydroxyl acylation analyzed by primer extension) was used to compare the effect of Mg2+, Fe2+, and Mn2+ on the tertiary structure of rRNA. Then, we used in vitro translation reactions to test whether Fe2+ or Mn2+ could mediate protein production, and quantified ribosomal metal content. We found that (i) Mg2+, Fe2+, and Mn2+ had strikingly similar effects on rRNA folding; (ii) Fe2+ and Mn2+ can replace Mg2+ as the dominant divalent cation during translation of mRNA to functional protein; and (iii) Fe and Mn associate extensively with the ribosome. Given that the translation system originated and matured when Fe2+ and Mn2+ were abundant, these findings suggest that Fe2+ and Mn2+ played a role in early ribosomal evolution

Magnetic irreversibility and Verwey transition in nano-crystalline bacterial magnetite

The magnetic properties of biologically-produced magnetite nanocrystals biomineralized by four different magnetotactic bacteria were compared to those of synthetic magnetite nanocrystals and large, high quality single crystals. The magnetic feature at the Verwey temperature, $T_{V}$, was clearly seen in all nanocrystals, although its sharpness depended on the shape of individual nanoparticles and whether or not the particles were arranged in magnetosome chains. The transition was broader in the individual superparamagnetic nanoparticles for which $T_{B}<T_{V}$, where $T_{B}$ is the superparamagnetic blocking temperature. For the nanocrystals organized in chains, the effective blocking temperature $T_{B}>T_{V}$ and the Verwey transition is sharply defined. No correlation between the particle size and $T_{V}$ was found. Furthermore, measurements of $M(H,T,time)$ suggest that magnetosome chains behave as long magnetic dipoles where the local magnetic field is directed along the chain and this result confirms that time-logarithmic magnetic relaxation is due to the collective (dipolar) nature of the barrier for magnetic moment reorientation

Use of coping strategies in MND/ALS:association with demographic and disease-related characteristics

Objective Understanding the use of coping strategies and which factors are associated with strategy utilization might help clinical staff anticipate which coping strategies individuals are more likely to utilize. In this study, we assess coping strategy use in the motor neuron disease (MND, also known as amyotrophic lateral sclerosis [ALS]) population and examine associations of demographic and disease variables with individual coping strategies. Participants and Methods A total of 233 participants with MND/ALS were recruited into the ongoing Trajectories of Outcomes in Neurological Conditions study from MND clinics across the United Kingdom. Participants completed a questionnaire pack collecting data on demographics and a range of patient‐reported measures including the Coping Orientations to Problems Experienced scale. Associations between demographic and clinical characteristics and coping strategies were examined by simple and multiple ordinal logistic regression. Results The most commonly used strategy was Acceptance, followed by Active Coping, Planning and Positive Re‐interpretation and Growth. The least used strategies were Substance Use, Turning to Religion and Denial. Ten out of the fifteen strategies showed statistically significant associations with demographic and clinical characteristics. Most markedly, females were found to utilize many strategies more than males, namely Restraint, Seeking Instrumental Social Support, Seeking Emotional Social Support, Focus on and Venting of Emotions, Behavioural Disengagement and Mental Disengagement. Conclusion Clinical staff should be aware that coping strategy use is associated with several demographic and disease characteristics. Targeted advice on coping may improve coping capacity and facilitate psychosocial adjustment

The energy use implications of 5G: reviewing whole network operational energy, embodied energy, and indirect effects

The energy efficiency and consumption of mobile networks have received increasing attention from academics and industry in recent years. This has been provoked by rapid increases in mobile data traffic and projected further rapid increases over the next decade. As a result, dramatic improvements in the energy efficiency of mobile networks are required to ensure that future traffic levels are both environmentally and economically sustainable. In this context, a good deal of research has focused on technologies and strategies that can improve the energy efficiency of 5G and future mobile networks more broadly. However, existing reviews in the field of green or sustainable mobile communications on the topic of the energy use implications of 5G overlook a number of issues that broader literatures on the energy use impacts of ICTs suggest could be significant. Addressing this gap, we conduct a literature review to examine whole network level assessments of the operational energy use implications of 5G, the embodied energy use associated with 5G, and indirect effects associated with 5G-driven changes in user behaviour and patterns of consumption and production in other sectors of the economy. In general, we find that these issues and their energy use implications have received insufficient attention in publicly available studies on the energy use impacts of 5G

Characterization of Propellant Flow and Bias Required to Initiate an Arc Discharge in a Heaterless Hollow Cathode

Heaterless hollow cathodes provide an opportunity to reduce complexity and improve reliability in electric propulsion systems. While removal of the heater has little effect on steady-state operation of a hollow cathode, it has a considerable effect on the ignition process. To successfully integrate a heaterless hollow cathode into a spaceflight electric propulsion system, it will be necessary to establish definitive requirements for the propellant feed and electrical subsystems so that ignition of a plasma discharge can be achieved reliably. The aim of this research was to form a better understanding of these requirements by performing an investigation of the propellant flow and voltage conditions required for the ignition of a plasma arc discharge. This aim was achieved by performing discharge initiation experiments using both a specially designed experimental apparatus and a functional heaterless hollow cathode assembly. It was demonstrated that there is a distinct difference in the voltage required to initiate a plasma discharge between two common electric propulsion propellants, xenon and krypton, which suggests that the developmental testing of heaterless hollow cathodes needs to be performed with the appropriate propellant gas species. Heaterless hollow cathode ignition experiments showed that the keeper orifice diameter has a strong effect on the voltage required to ignite a plasma discharge at a given propellant mass flow rate, while the effect of keeper-cathode separation distance was only strong at flow rates below 25 sccm (Xe)

Evolutionary engineering improves tolerance for replacement jet fuels in Saccharomyces cerevisiae

Monoterpenes are liquid hydrocarbons with applications ranging from flavor and fragrance to replacement jet fuel. Their toxicity, however, presents a major challenge for microbial synthesis. Here we evolved limonene-tolerant Saccharomyces cerevisiae strains and sequenced six strains across the 200-generation evolutionary time course. Mutations were found in the tricalbin proteins Tcb2p and Tcb3p. Genomic reconstruction in the parent strain showed that truncation of a single protein (tTcb3p(1-989)), but not its complete deletion, was sufficient to recover the evolved phenotype improving limonene fitness 9-fold. tTcb3p(1-989) increased tolerance toward two other monoterpenes (beta-pinene and myrcene) 11- and 8-fold, respectively, and tolerance toward the biojet fuel blend AMJ-700t (10% cymene, 50% limonene, 40% farnesene) 4-fold. tTcb3p(1-989) is the first example of successful engineering of phase tolerance and creates opportunities for production of the highly toxic C-10 alkenes in yeast