Progress towards robotic exploration of extreme terrain

A high degree of mobility, reliability, and efficiency are needed for autonomous exploration of extreme terrain. These requirements have guided the development of the Ambler, a six-legged robot designed for planetary exploration. To address issues of efficiency and mobility, the Ambler is configured with a stacked arrangement of orthogonal legs and exhibits a unique circulating gait, where trailing legs recover directly from rear to front. The Ambler is designed to stably traverse a 30 degree slope while crossing meter sized features. The same three principles have provided many constraints on the design of a software system that autonomously navigates the Ambler through natural terrain using 3-D perception and a combined deliberative/reactive architecture. The software system has required research advances in real-time control, perception of rugged terrain, motion planning, task-level control, and system integration. This paper presents many of the factors that influenced the design of the Ambler and its software system. In particular, important assumptions regarding the mechanism, perception, planning, and control are presented and evaluated in light of experimental and theoretical research of this project.     

Investigating newcomer expectations and job-related outcomes.

The initial experiences of newcomers as they enter an organization can provide important information that substantially influences the subsequent relationship between the individual and the organization. For example, the application of realistic job previews (RJPs) often results in desirable organizational outcomes (e.g., increased satisfaction and reduced turnover). RJPs are typically job specific and job-content laden and serve to reduce the expectations of organizational newcomers. The present study indicates that an expectation lowering procedure (ELP), which is not job specific and is relatively content free, may yield similar benefits (i.e., reduce expectations). Both the organizational implications of this research and suggestions for using ELPs in conjunction with RJPs in the newcomer socialization process are offered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pulse electro-thermal de-icer (PETD)

De-icing is a process in which interfacial ice attached to a structure is either broken or melted and then the ice is removed by some sort of external force (e.g. gravity or wind-drag). Conventional thermal de-icing is effective but requires too much energy. Mechanical de-icing requires less energy but is less effective, often leaving significant amounts of ice behind, and may also damage structures and accelerate wear. We have invented, developed, and tested a pulse electro-thermal de-icer (PETD) that reduces the energy needed for de-icing by up to a factor of one hundred. PETD achieves this by melting only a thin layer of interfacial ice, leaving the temperature of the environment unchanged.In conventional de-icers, the heater is thermally connected to the ice, the structure, and the outside environment. This makes heat losses through conduction and convection inevitable to the point where the losses exceed by orders of magnitude the amount of “useful” heat needed to melt the interfacial ice. PETD cuts these losses by using a short heating pulse - approximately 1 ms to 5s long - to heat a minimal layer of interfacial ice. This short heating time limits the heat penetration depth into both the ice and the structure. A PETD pulse heats the ice-structure interface just above the melting point causing the ice to slide off on the resulting thin water film.PETD was successfully tested for a variety of applications including the de-icing of airplanes, car windshields, bridge over-structures, glass roofs, commercial and residential icemakers, and windmill rotors. The tests demonstrated almost instant action along with up to 99% savings of the electricity required by conventional thermal de-icers.This paper presents the PETD method, its theory, results of computer simulations, and extensive data from laboratory tests as well as several large-scale implementations of PETD on an airplane, a bridge, a building roof (> 10,000 m²), a car windshield, and a commercial ice maker.     

An Aboveground Pulse-Tube-Based Bolometric Test Facility for the Validation of the LUMINEU \hbox {ZnMoO}_4 Crystals

The LUMINEU project aims at developing a pilot double beta decay experiment using scintillating bolometers based on ZnMoO \(_4\) crystals enriched in \(^{100}\hbox {Mo}\) . In the next months regular deliveries of large-mass \(\hbox {ZnMoO}_4\) crystals are expected from the Nikolaev Institute of Inorganic Chemistry (Novosibirsk, Russia). It is therefore crucial for the LUMINEU program to test systematically and in real time these samples in terms of bolometric properties, light yield and internal radioactive contamination. In this paper we describe an aboveground cryogenic facility based on a dilution refrigerator coupled to a pulse-tube cooler capable performing these measurements. A 23.8 g \(\hbox {ZnMoO}_4\) crystal was fully characterised in this setup. We show also that macro-bolometers can be operated with high signal-to-noise ratio in liquid-free dilution refrigerators.     

The effects of transformational and change leadership on employees' commitment to a change: A multilevel study.

The effects of transformational leadership on the outcomes of specific change initiatives are not well understood. Conversely, organizational change studies have examined leader behaviors during specific change implementations yet have failed to link these to broader leadership theories. In this study, the authors investigate the relationship between transformational and change leadership and followers' commitment to a particular change initiative as a function of the personal impact of the changes. Transformational leadership was found to be more strongly related to followers' change commitment than change-specific leadership practices, especially when the change had significant personal impact. For leaders who were not viewed as transformational, good change-management practices were found to be associated with higher levels of change commitment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

cNTnC and fYTnC2, Genetically Encoded Green Calcium Indicators Based on Troponin C from Fast Animals

NTnC-like green fluorescent genetically encoded calcium indicators (GECIs) with two calcium ion binding sites were constructed using the insertion of truncated troponin C (TnC) from Opsanus tau into green fluorescent proteins (GFPs). These GECIs are small proteins containing the N- and C-termini of GFP; they exert a limited effect on the cellular free calcium ion concentration; and in contrast to calmodulin-based calcium indicators they lack undesired interactions with intracellular proteins in neurons. The available TnC-based NTnC or YTnC GECIs had either an inverted response and high brightness but a limited dynamic range or a positive response and fast kinetics in neurons but lower brightness and an enhanced but still limited dF/F dynamic range. Here, we solved the crystal structure of NTnC at 2.5 Å resolution. Based on this structure, we developed positive NTnC2 and inverted iNTnC2 GECIs with a large dF/F dynamic range in vitro but very slow rise and decay kinetics in neurons. To overcome their slow responsiveness, we swapped TnC from O. tau in NTnC2 with truncated troponin C proteins from the muscles of fast animals, namely, the falcon, hummingbird, cheetah, bat, rattlesnake, and ant, and then optimized the resulting constructs using directed molecular evolution. Characterization of the engineered variants using purified proteins, mammalian cells, and neuronal cultures revealed cNTnC GECI with truncated TnC from Calypte anna (hummingbird) to have the largest dF/F fluorescence response and fast dissociation kinetics in neuronal cultures. In addition, based on the insertion of truncated TnCs from fast animals into YTnC2, we developed fYTnC2 GECI with TnC from Falco peregrinus (falcon). The purified proteins cNTnC and fYTnC2 had 8- and 6-fold higher molecular brightness and 7- and 6-fold larger dF/F responses to the increase in Ca²⁺ ion concentration than YTnC, respectively. cNTnC GECI was also 4-fold more photostable than YTnC and fYTnC2 GECIs. Finally, we assessed the developed GECIs in primary mouse neuronal cultures stimulated with an external electric field; in these conditions, cNTnC had a 2.4-fold higher dF/F fluorescence response than YTnC and fYTnC2 and was the same or slightly slower (1.4-fold) than fYTnC2 and YTnC in the rise and decay half-times, respectively.     

Melatonin as a Potential Approach to Anxiety Treatment

Anxiety disorders are the most common mental diseases. Anxiety and the associated physical symptoms may disturb social and occupational life and increase the risk of somatic diseases. The pathophysiology of anxiety development is complex and involves alterations in stress hormone production, neurosignaling pathways or free radical production. The various manifestations of anxiety, its complex pathophysiological background and the side effects of available treatments underlie the quest for constantly seeking therapies for these conditions. Melatonin, an indolamine produced in the pineal gland and released into the blood on a nightly basis, has been demonstrated to exert anxiolytic action in animal experiments and different clinical conditions. This hormone influences a number of physiological actions either via specific melatonin receptors or by receptor-independent pleiotropic effects. The underlying pathomechanism of melatonin’s benefit in anxiety may reside in its sympatholytic action, interaction with the renin–angiotensin and glucocorticoid systems, modulation of interneuronal signaling and its extraordinary antioxidant and radical scavenging nature. Of importance, the concentration of this indolamine is significantly higher in cerebrospinal fluid than in the blood. Thus, ensuring sufficient melatonin production by reducing light pollution, which suppresses melatonin levels, may represent an endogenous neuroprotective and anxiolytic treatment. Since melatonin is freely available, economically undemanding and has limited side effects, it may be considered an additional or alternative treatment for various conditions associated with anxiety.