Gravitational tolerance and size of <i>Brachiosaurus brancai</i>

In an earlier study, Gunga et al. (1999) determined body size and body volume distribution by photogrammetry in sauropods from the Upper Jurassic in Tendaguru (Tanzania, East Africa). Specifically, they found a body mass of about 74400 kg for a specimen of Brachiosaurus brancai. By means of dimensional analysis and a theory of biological similarity, moreover, it was possible to estimate the numerical value of the allometric exponent (b = −0.17) for gravitational tolerance (Gmax) of animals living on earth, which changes with the body mass. This theoretical exponent is close to Economos' empirical finding (b = −0.14). Our results show that there remains an unsolved contradiction between the theoretical assumptions for Gmax for the body mass of the largest fully terrestrial animals. In einer vorangehenden Studie (Gunga et al. 1999) wurde mit Hilfe der Photogrammetrie die Körpermassen und Körpervolumenverteilung von jurassischen Sauropoden aus Tendaguru (Tansania, Ostafrika) ermittelt. Diese Bestimmungen ergaben für Brachiosaurus brancai eine Körpermasse von von ca. 74400 kg. Weitere Studien aus der vergleichenden Physiologie haben gezeigt, dass die Toleranz bei Schwerkraftbelastung (Gmax) mit der Körpermasse variert. Durch dimensionale Analyse und vergleichende Studien konnte ein allometrischer Exponent für die Toleranz bei Schwerkraftbelastung mit b = −0.17 für terrestrische Organismen bestimmt werden. Dieser theoretische Exponent kommt den empirischen Befunden von Economos (b = −0.14) nahe. Dennoch weisen diese vorliegenden Berechnungen damit auf einen Widerspruch bei den bislang vorhandenen theoretischen Überlegungen zur Gmax bei den grössten maximalen Körpermassen für terrestrisch lebende Organismen hin. doi:10.1002/mmng.20020050115</a

The Association of Fatigue With Decreasing Regularity of Locomotion During an Incremental Test in Trained and Untrained Healthy Adults

Fatigue is a key factor that affects human motion and modulates physiology, biochemistry, and performance. Prolonged cyclic human movements (locomotion primarily) are characterized by a regular pattern, and this extended activity can induce fatigue. However, the relationship between fatigue and regularity has not yet been extensively studied. Wearable sensor methodologies can be used to monitor regularity during standardized treadmill tests (e.g., the widely used Bruce test) and to verify the effects of fatigue on locomotion regularity. Our study on 50 healthy adults [27 males and 23 females; &lt;40&nbsp;years; five dropouts; and 22 trained (T) and 23 untrained (U) subjects] showed how locomotion regularity follows a parabolic profile during the incremental test, without exception. At the beginning of the trial, increased walking speed in the absence of fatigue is associated with increased regularity (regularity index, RI, a. u., null/unity value for aperiodic/periodic patterns) up until a peak value (RI&nbsp;=&nbsp;0.909 after 13.8&nbsp;min for T and RI&nbsp;=&nbsp;0.915 after 13.4&nbsp;min for U subjects; median values, n. s.) and which is then generally followed (after 2.8 and 2.5&nbsp;min, respectively, for T/U, n. s.) by the walk-to-run transition (at 12.1&nbsp;min for both T and U, n. s.). Regularity then decreases with increased speed/slope/fatigue. The effect of being trained was associated with significantly higher initial regularity [0.845 (T) vs 0.810 (U), p&nbsp;&lt;&nbsp;0.05 corrected], longer test endurance [23.0&nbsp;min (T) vs 18.6&nbsp;min (U)], and prolonged decay of locomotor regularity [8.6&nbsp;min (T) vs 6.5&nbsp;min (U)]. In conclusion, the monitoring of locomotion regularity can be applied to the Bruce test, resulting in a consistent time profile. There is evidence of a progressive decrease in regularity following the walk-to-run transition, and these features unveil significant differences among healthy trained and untrained adult subjects

A new body mass estimation of <i>Brachiosaurus brancai</i> Janensch, 1914 mounted and exhibited at the Museum of Natural History (Berlin, Germany)

Body mass and surface areas are important in several aspects for an organism living today. Therefore, mass and surface determinations for extinct dinosaurs could be important for paleo-biological aspects as well. Based on photogrammetrical measurement the body mass and body surface area of the Late Jurassic Brachiosaurus brancai Janensch, 1914 from Tendaguru (East Africa), a skeleton mounted and exhibited at the Museum of Natural History in Berlin (Germany), has been re-evaluated. We determined for a slim type of 3D reconstruction of Brachiosaurus brancai a total volume of 47.9 m3 which represents, assuming a mean tissue density of 0.8 kg per 1,000 cm3, a total body mass of 38,000 kg. The volume distributions from the head to the tail were as follows: 0.2 m3 for the head, neck 7.3 m3, fore limbs 2.9 m3, hind limbs 2.6 m3, thoracic-abdominal cavity 32.4 m3, tail 2.2 m3. The total body surface area was calculated to be 119.1 m2, specifically 1.5 m2 for the head, 26 m2 neck, fore limbs 18.8 m2, hind limbs 16.4 m2, 44.2 m2 thoracic-abdominal cavity, and finally the tail 12.2 m2. Finally, allometric equations were used to estimate presumable organ sizes of this extinct dinosaur and to test whether their dimensions really fit into the thoracic and abdominal cavity of Brachiosaurus brancai if a slim body shape of this sauropod is assumed. doi:10.1002/mmng.200700011</a

Анализ технологических параметров работы мембранных систем извлечения гелия из природного газа в процессе разработки газовых месторождений

Объектом исследования являются технологии выделения гелия из состава природного газа. Цель исследования – анализ технологических параметров работы мембранных систем выделения гелия из природного газа в процессе разработки газовых месторождений. В процессе исследования были рассмотрены существующие технологии выделения гелиевого концентрата, проанализированы основные производственные характеристики данных систем. Проведен анализ технологии мембранного выделения гелиевого концентрата и рассмотрены перспективы в использовании современных установок на основе мембранного разделения. В результате проведенного анализа был выявлен положительный эффект от внедрения модульных установок мембранного выделения гелиевого концентрата.The object of the research is technologies for the separation of helium from natural gas. The aim of the study is to analyze the technological parameters of the operation of membrane systems for the extraction of helium from natural gas during the development of gas fields. In the course of the research, the existing technologies for the separation of helium concentrate were considered, the main production characteristics of these systems were analyzed. The analysis of the technology of membrane separation of helium concentrate is carried out and the prospects for the use of modern installations based on membrane separation are considered

Predation upon Hatchling Dinosaurs by a New Snake from the Late Cretaceous of India

A new snake from Upper Cretaceous rocks in India is found with hatchling sauropod dinosaurs, demonstrating that large, gape-limited snakes were probably capable of taking in moderate-sized vertebrate prey

Fluid Shifts

INTRODUCTION: Mechanisms responsible for the ocular structural and functional changes that characterize the visual impairment and intracranial pressure (ICP) syndrome (VIIP) are unclear, but hypothesized to be secondary to the cephalad fluid shift experienced in spaceflight. This study will relate the fluid distribution and compartmentalization associated with long-duration spaceflight with VIIP symptoms. We also seek to determine whether the magnitude of fluid shifts during spaceflight, as well as the VIIP-related effects of those shifts, can be predicted preflight with acute hemodynamic manipulations, and also if lower body negative pressure (LBNP) can reverse the VIIP effects. METHODS: Physiologic variables will be examined pre-, in- and post-flight in 10 International Space Station crewmembers including: fluid compartmentalization (D2O and NaBr dilution); interstitial tissue thickness (ultrasound); vascular dimensions and dynamics (ultrasound and MRI (including cerebrospinal fluid pulsatility)); ocular measures (optical coherence tomography, intraocular pressure, ultrasound); and ICP measures (tympanic membrane displacement, otoacoustic emissions). Pre- and post-flight measures will be assessed while upright, supine and during 15 deg head-down tilt (HDT). In-flight measures will occur early and late during 6 or 12 month missions. LBNP will be evaluated as a countermeasure during HDT and during spaceflight. RESULTS: The first two crewmembers are in the preflight testing phase. Preliminary results characterize the acute fluid shifts experienced from upright, to supine and HDT postures (increased stroke volume, jugular dimensions and measures of ICP) which are reversed with 25 millimeters Hg LBNP. DISCUSSION: Initial results indicate that acute cephalad fluid shifts may be related to VIIP symptoms, but also may be reversible by LBNP. The effect of a chronic fluid shift has yet to be evaluated. Learning Objectives: Current spaceflight VIIP research is described, including novel hardware and countermeasures

Biomechanics of Running Indicates Endothermy in Bipedal Dinosaurs

One of the great unresolved controversies in paleobiology is whether extinct dinosaurs were endothermic, ectothermic, or some combination thereof, and when endothermy first evolved in the lineage leading to birds. Although it is well established that high, sustained growth rates and, presumably, high activity levels are ancestral for dinosaurs and pterosaurs (clade Ornithodira), other independent lines of evidence for high metabolic rates, locomotor costs, or endothermy are needed. For example, some studies have suggested that, because large dinosaurs may have been homeothermic due to their size alone and could have had heat loss problems, ectothermy would be a more plausible metabolic strategy for such animals.Here we describe two new biomechanical approaches for reconstructing the metabolic rate of 14 extinct bipedal dinosauriforms during walking and running. These methods, well validated for extant animals, indicate that during walking and slow running the metabolic rate of at least the larger extinct dinosaurs exceeded the maximum aerobic capabilities of modern ectotherms, falling instead within the range of modern birds and mammals. Estimated metabolic rates for smaller dinosaurs are more ambiguous, but generally approach or exceed the ectotherm boundary.Our results support the hypothesis that endothermy was widespread in at least larger non-avian dinosaurs. It was plausibly ancestral for all dinosauriforms (perhaps Ornithodira), but this is perhaps more strongly indicated by high growth rates than by locomotor costs. The polarity of the evolution of endothermy indicates that rapid growth, insulation, erect postures, and perhaps aerobic power predated advanced “avian” lung structure and high locomotor costs