A pilot test of the effect of mild-hypoxia on unrealistically optimistic risk judgements

Although hypoxia is believed to occur above altitudes of 10,000 ft, some have suggested that effects may occur at lower altitudes. This pilot study explored risk judgments under conditions of mild hypoxia (simulated altitude of 8,000 ft). Some evidence of an increased optimism was found at this level, suggesting the need for a larger scale study with more experimental power

Self-paced aerobic exercise performance is attenuated following four hours cold water immersion

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Hyperthermia Does Not Alter Baroreflex Control Of Heart Rate During Central Hypovolemia Associated With Simulated Hemorrhage. .

Baroreceptors modulate arterial blood pressure through neural control of cardiac output and peripheral vascular resistance. Hyperthermia reduces tolerance to central hypovolemia, however hyperthermia itself does not alter baroreflex control of heart rate or muscle sympathetic nerve activity. The combined influence of hyperthermia and profound central hypovolemia on baroreflex function remains unknown. This study tested the hypothesis that baroreflex sensitivity (as indexed from ∆ heart rate /∆ blood pressure) would be reduced in hyperthermia compared to normothermia during central hypovolemia. Twelve healthy males (32 ± 5 y) underwent central hypovolemia to pre-syncope, which was induced via progressive lower body negative pressure (LBNP), during normothermia and, on a separate day (randomized, counter balanced) during hyperthermia (+1.2 ± 0.1°C increase in internal temperature). Baroreflex sensitivity was assessed during the final full stage of LBNP completed, and during a 30 second period immediately preceding any bradycardia prior to pre-syncope. LBNP during hyperthermia reduced tolerance by ~58% relative to LBNP during normothermia (normothermia: 72mmHg ±20 vs hyperthermia: 42mmHg± 13; P\u3c0.001). During the final full LBNP stage, baroreflex sensitivity was not different between thermal conditions (hyperthermia: 1.9 ± 1.6 bpm/mmHg, normothermia: 2.4 ± 1.5 bpm/mmHg, p=0.46). Likewise, just prior to pre-syncope baroreflex sensitivity between thermal conditions was not different (hyperthermia: 1.0±1.3 bpm/mmHg, normothermia: 1.5±1.1 bpm/mmHg; p=0.10). These data indicate that during profound central hypovolemia baroreflex control of heart rate is unaffected by hyperthermia. Thus, reductions in the capacity to tolerate central hypovolemia while hyperthermic is not related to altered baroreflex control of heart rate

Hydration Status Response to Bolus Frequency and Volume Intake During Exercise in Heat

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The threshold ambient temperature for the use of precooling to improve cycling time-trial performance

Purpose: Cycling time trial performance can be compromised by moderate to high ambient temperatures. It has become commonplace to implement pre-cooling prior to competition to alleviate this performance decline. However, little is known about the ambient temperature threshold above which pre-cooling becomes an effective strategy for enhancing endurance performance. It was the aim of this study to investigate the effect of pre-cooling in different environmental temperatures on time trial performance. Methods: Trained cyclists completed two time trials with (COLD) and without (CON) pre-cooling using an ice-vest and sleeves ensemble in ambient temperatures of 24˚C, 27˚C and 35˚C. Results: Time trial performance faster following COLD in both 35˚C (6.2%) and 27˚C (2.6%; both P<0.05) but not 24˚C (1.2%). Magnitude based inferential statistics indicate that COLD was very likely beneficial to performance in 35˚C and likely beneficial in 27˚C and possibly beneficial in 24°C. Mean power was 2.4%, 2.5% and 5.6% higher following COLD and considered to be likely beneficial in 24°C and very likely beneficial in 27˚C and 35˚C. COLD reduced mean skin temperature throughout the warm-up and into the time trial in all ambient temperatures (P<0.05). Sweat loss was lower following COLD in 24˚C and 27˚C but not 35˚C. There was no effect of COLD on gastrointestinal temperature at any point. Conclusions: Pre-cooling with an ice-vest and sleeves is likely to have a positive effect on time trial performance at temperatures above 24˚C, with a clear relationship between ambient temperature and the magnitude of effect of pre-coolin

Face Cooling Reveals Transient Cardiac Parasympathetic Dysfunction in Recently Concussed College Athletes

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Experimental Evaluation of Engineered Cementitious Composites as Reflective Crack Control Interlayer for Composite Pavements

Reflective cracking at transverse joints is considered as a predominant distress in composite pavements. Various interlayers have been used previously to prevent or retard reflective cracking. Engineered cementitious composite (ECC) is a special type of high-performance fiber-reinforced cementitious material that is expected to perform better as an interlayer due to its higher tensile strength and ductility. This study aims to evaluate the effectiveness of ECC as an interlayer system experimentally. A laboratory test protocol was designed to simulate repeated traffic loads to measure the fatigue performance of ECC interlayer system using digital image correlation (DIC) technique. It was found that the composite pavement specimens with ECC interlayer provided significantly higher fatigue life as compared to the control specimens without interlayer. This result indicates that ECC could be used as a potential effective interlayer system to retard or mitigate reflective cracking

Cerebral Blood Velocity Increases during Face Cooling in Symptomatic Concussed Athletes

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El Laboratorio de Virtualización 3D de Idaho

[EN] Three dimensional (3D) virtualization and visualization is an important component of industry, art, museum curation and cultural heritage, yet the step by step process of 3D virtualization has been little discussed. Here we review the Idaho Virtualization Laboratory’s (IVL) process of virtualizing a cultural heritage item (artifact) from start to finish. Each step is thoroughly explained and illustrated including how the object and its metadata are digitally preserved and ultimately distributed to the world.[ES] La virtualización y visualización tridimensional (3D) es un componente importante de la industria, el arte, los museos y el patrimonio cultural, sin embargo, el proceso paso a paso de virtualización 3D se ha discutido muy poco. Aquí repasamos de principio a fin el proceso de virtualizacion de un elemento del patrimonio cultural (artefacto) llevado a cabo por el Laboratorio de Virtualización de Idaho (IVL). Cada paso es explicado e ilustrado completamente incluyendo cómo el objeto y sus metadatos son preservados digitalmente y en última instancia, distribuidos en el mundo.The authors would like to thank the National Science Foundation (awards ARC- 0808933, 102332, 1237452 and 1321411), the Hitz Foundation, the M. J. Murdock Charitable Trust, Idaho State University, the ISU Informatics Research Institute, and the Idaho Museum of Natural History for supporting this research. The National Science Foundation, nor any other funding source, is responsible for the advancements, conclusions, or implications of this work.Holmer, NA.; Clement, N.; Dehart, K.; Maschner, H.; Pruitt, J.; Schlader, R.; Van Walsum, M. (2014). The Idaho Virtualization Laboratory 3D Pipeline. Virtual Archaeology Review. 5(10):21-31. https://doi.org/10.4995/var.2014.4208OJS2131510BETTS, M. W., MASCHNER, H. D. G., SCHOU, C. D., SCHLADER, R., HOLMES, J., CLEMENT, N., SMUIN, M. (2011): "Virtual zooarchaeology: building a web-based reference collection of northern vertebrates for archaeofaunal research and education", in Journal of Archaeological Science, Volume: 38, Issue: 4, pp. 755-762.MASCHNER, H. (2013): "Democracy in 3D", in Museum, pp. 26-31.MASCHNER, H., SCHOU, C., HOLMES, J. (2013): "Virtualization and the democratization of science: 3D technologies revolutionize museum research and Access", in Proceedings of the 2013 World Digital Heritage Conference. -1-4799-3169-9/13©2013 IEEE. http://dx.doi.org/10.1109/DigitalHeritage.2013.6744763TAPANILA, L., PRUITT, J., PRADEL, A., WILGA, C. D., RAMSAY, J. B., SCHLADER, R., DIDIER, D. A. (2013): "Jaws for a spiral-tooth whorl: CT images reveal novel adaptation and phylogeny in fossil Helicoprion", in Biology Letters, 9, 20130057 http://dx.doi.org/10.1098/rsbl.2013.005

Identification of a Pre-Contact Polar Bear Victim at Native Point, Southampton Island, Nunavut, Using 3D Technology and a Virtual Zooarchaeology Collection

The skeletal remains of an adult Sadlermiut woman with obvious trauma to her cranial and post-cranial skeleton were excavated from Native Point (KkHh-1), Southampton Island, Nunavut, in 1954. In order to determine the possible cause of this damage, we first documented the skeletal injuries using traditional bioarchaeological techniques. We then created a three-dimensional model of the cranium and mandible to permit better visualization and analysis of the cranial lesions, some of which were obscured by post-depositional weathering. This model was imported into a virtual environment in order to compare the lesions with the craniodental structure of four Arctic carnivore species available as digital models through the Virtual Zooarchaeology of the Arctic Project (VZAP), an online comparative faunal collection. We eliminated all but the polar bear (Ursus maritimus) using this process, which suggested that an individual of this species was responsible for the skeletal trauma. We further identified a minimum number of “bites” on the cranium, some with overlapping lesions, which suggested a possible attack sequence. Use of a virtual environment and an online comparative collection were critical to this process and represent a new technique for evaluating past skeletal trauma and its causes.En 1954, lors de travaux archéologiques sur le site Native Point (KkHh-1), île Southampton, Nunavut, les restes du squelette d’une femme adulte de la culture Sadlermiut portant des signes évidents de traumatismes crânien et post-crânien avaient été excavés. Dans le but de déterminer les causes possibles de ces dommages, nous avons d’abord documenté les lésions squelettiques à l’aide de techniques bio-archéologiques traditionnelles. Ensuite, nous avons créé un modèle en trois dimensions du crâne et de la mandibule pour permettre de bien visualiser et analyser les lésions crâniennes, notamment parce que certaines d’entre elles étaient obscurcies par l’érosion post-dépositionnelle. Ce modèle a été importé dans un environnement virtuel afin de comparer les lésions à la structure cranio-dentaire de quatre espèces carnivores provenant de l’Arctique dont les modèles figurent déjà dans la collection ostéologique comparative en ligne du projet VZAP (Virtual Zooarchaeology of the Arctic Project). Nous avons ainsi éliminé tous les carnivores à l’exception de l’ours polaire (Ursus maritimus), laissant penser qu’un membre de cette espèce serait responsable des traumatismes du squelette de cette femme. Nous avons également identifié des morsures sur le crâne de cette femme, suggérant une possible séquence d’attaques, ne serait-ce que par la présence d’une série de lésions qui se chevauchent. L’utilisation d’un environnement virtuel et d’une collection comparative virtuelle a joué un rôle déterminant dans ce processus et représente une nouvelle technique pour évaluer les traumatismes squelettiques anciens et leurs causes