The minimum energy expenditure shortest path method

This article discusses the addition of an energy parameter to the shortest path execution process; namely, the energy expenditure by a character during execution of the path. Given a simple environment in which a character has the ability to perform actions related to locomotion, such as walking and stair stepping, current techniques execute the shortest path based on the length of the extracted root trajectory. However, actual humans acting in constrained environments do not plan only according to shortest path criterion, they conceptually measure the path that minimizes the amount of energy expenditure. On this basis, it seems that virtual characters should also execute their paths according to the minimization of actual energy expenditure as well. In this article, a simple method that uses a formula for computing vanadium dioxide ($VO_2$) levels, which is a proxy for the energy expenditure by humans during various activities, is presented. The presented solution could be beneficial in any situation requiring a sophisticated perspective of the path-execution process. Moreover, it can be implemented in almost every path-planning method that has the ability to measure stepping actions or other actions of a virtual character

Optimization And Learning For Rough Terrain Legged Locomotion

We present a novel approach to legged locomotion over rough terrain that is thoroughly rooted in optimization. This approach relies on a hierarchy of fast, anytime algorithms to plan a set of footholds, along with the dynamic body motions required to execute them. Components within the planning framework coordinate to exchange plans, cost-to-go estimates, and \u27certificates\u27 that ensure the output of an abstract high-level planner can be realized by lower layers of the hierarchy. The burden of careful engineering of cost functions to achieve desired performance is substantially mitigated by a simple inverse optimal control technique. Robustness is achieved by real-time re-planning of the full trajectory, augmented by reflexes and feedback control. We demonstrate the successful application of our approach in guiding the LittleDog quadruped robot over a variety of types of rough terrain. Other novel aspects of our past research efforts include a variety of pioneering inverse optimal control techniques as well as a system for planning using arbitrary pre-recorded robot behavior

SorCS2 facilitates release of endostatin from astrocytes and controls post-stroke angiogenesis

SorCS2 is an intracellular sorting receptor of the VPS10P domain receptor gene family recently implicated in oxidative stress response. Here, we interrogated the relevance of stress-related activities of SorCS2 in the brain by exploring its role in ischemic stroke in mouse models and in patients. Although primarily seen in neurons in the healthy brain, expression of SorCS2 was massively induced in astrocytes surrounding the ischemic core in mice following stroke. Post-stroke induction was likely a result of increased levels of transforming growth factor β1 in damaged brain tissue, inducing Sorcs2 gene transcription in astrocytes but not neurons. Induced astrocytic expression of SorCS2 was also seen in stroke patients, substantiating the clinical relevance of this observation. In astrocytes in vitro and in the mouse brain in vivo, SorCS2 specifically controlled release of endostatin, a factor linked to post-stroke angiogenesis. The ability of astrocytes to release endostatin acutely after stroke was lost in mice deficient for SorCS2, resulting in a blunted endostatin response which coincided with impaired vascularization of the ischemic brain. Our findings identified activated astrocytes as a source for endostatin in modulation of post-stroke angiogenesis, and the importance of the sorting receptor SorCS2 in this brain stress response

The effect of acetaminophen (four grams a day for three consecutive days) on hepatic tests in alcoholic patients – a multicenter randomized study

Background: Hepatic failure has been associated with reported therapeutic use of acetaminophen by alcoholic patients. The highest risk period for alcoholic patients is immediately after discontinuation of alcohol intake. This period exhibits the largest increase in CYP2E1 induction and lowest glutathione levels. Our hypothesis was that common liver tests would be unaffected by administration of the maximum recommended daily dosage of acetaminophen for 3 consecutive days to newly-abstinent alcoholic subjects. Methods: Adult alcoholic subjects entering two alcohol detoxification centers were enrolled in a prospective double-blind, randomized, placebo-controlled trial. Subjects were randomized to acetaminophen, 4 g/day, or placebo for 3 consecutive days. The study had 95% probability of detecting a 15 IU/L difference in serum ALT. Results: A total of 443 subjects were enrolled: 308 (258 completed) received acetaminophen and 135 subjects (114 completed) received placebo. Study groups did not differ in demographics, alcohol consumption, nutritional status or baseline laboratory assessments. The peak mean ALT activity was 57 [plus or minus] 45 IU/L and 55 [plus or minus] 48 IU/L in the acetaminophen and placebo groups, respectively. Subgroup analyses for subjects presenting with an elevated ALT, subjects fulfilling a diagnosis of alcoholic hepatitis and subjects attaining a peak ALT greater than 200 IU/L showed no statistical difference between the acetaminophen and control groups. The one participant developing an increased international normalized ratio was in the placebo group. Conclusion: Alcoholic patients treated with the maximum recommended daily dose of acetaminophen for 3 consecutive days did not develop increases in serum transaminase or other measures of liver injury. Treatment of pain or fever for 3 days with acetaminophen appears safe in newly-abstinent alcoholic patients, such as those presenting for acute medical care.Funding for this study was provided by McNeil Consumer Healthcare to the Denver Health Authority, Denver, Colorado

Major Depressive Disorder is Associated with Impaired Mitochondrial Function in Skin Fibroblasts

Mitochondrial malfunction is supposed to be involved in the etiology and pathology of major depressive disorder (MDD). Here, we aimed to identify and characterize the molecular pathomechanisms related to mitochondrial dysfunction in adult human skin fibroblasts, which were derived from MDD patients or non-depressive control subjects. We found that MDD fibroblasts showed significantly impaired mitochondrial functioning: basal and maximal respiration, spare respiratory capacity, non-mitochondrial respiration and adenosine triphosphate (ATP)-related oxygen consumption was lower. Moreover, MDD fibroblasts harbor lower ATP levels and showed hyperpolarized mitochondrial membrane potential. To investigate cellular resilience, we challenged both groups of fibroblasts with hormonal (dexamethasone) or metabolic (galactose) stress for one week, and found that both stressors increased oxygen consumption but lowered ATP content in MDD as well as in non-depressive control fibroblasts. Interestingly, the bioenergetic differences between fibroblasts from MDD or non-depressed subjects, which were observed under non-treated conditions, could not be detected after stress. Our findings support the hypothesis that altered mitochondrial function causes a bioenergetic imbalance, which is associated with the molecular pathophysiology of MDD. The observed alterations in the oxidative phosphorylation system (OXPHOS) and other mitochondria-related properties represent a basis for further investigations of pathophysiological mechanisms and might open new ways to gain insight into antidepressant signaling pathways

Effects of ocean acidification on invertebrate settlement at volcanic CO<inf>2</inf> vents

We present the first study of the effects of ocean acidification on settlement of benthic invertebrates and microfauna. Artificial collectors were placed for 1 month along pH gradients at CO2 vents off Ischia (Tyrrhenian Sea, Italy). Seventy-nine taxa were identified from six main taxonomic groups (foraminiferans, nematodes, polychaetes, molluscs, crustaceans and chaetognaths). Calcareous foraminiferans, serpulid polychaetes, gastropods and bivalves showed highly significant reductions in recruitment to the collectors as pCO2 rose from normal (336-341 ppm, pH 8.09-8.15) to high levels (886-5,148 ppm) causing acidified conditions near the vents (pH 7.08-7.79). Only the syllid polychaete Syllis prolifera had higher abundances at the most acidified station, although a wide range of polychaetes and small crustaceans was able to settle and survive under these conditions. A few taxa (Amphiglena mediterranea, Leptochelia dubia, Caprella acanthifera) were particularly abundant at stations acidified by intermediate amounts of CO2 (pH 7. 41-7.99). These results show that increased levels of CO2 can profoundly affect the settlement of a wide range of benthic organisms. © 2010 Springer-Verlag

Commissioning of the vacuum system of the KATRIN Main Spectrometer

The KATRIN experiment will probe the neutrino mass by measuring the beta-electron energy spectrum near the endpoint of tritium beta-decay. An integral energy analysis will be performed by an electro-static spectrometer (Main Spectrometer), an ultra-high vacuum vessel with a length of 23.2 m, a volume of 1240 m^3, and a complex inner electrode system with about 120000 individual parts. The strong magnetic field that guides the beta-electrons is provided by super-conducting solenoids at both ends of the spectrometer. Its influence on turbo-molecular pumps and vacuum gauges had to be considered. A system consisting of 6 turbo-molecular pumps and 3 km of non-evaporable getter strips has been deployed and was tested during the commissioning of the spectrometer. In this paper the configuration, the commissioning with bake-out at 300{\deg}C, and the performance of this system are presented in detail. The vacuum system has to maintain a pressure in the 10^{-11} mbar range. It is demonstrated that the performance of the system is already close to these stringent functional requirements for the KATRIN experiment, which will start at the end of 2016.Comment: submitted for publication in JINST, 39 pages, 15 figure