Hypocretin-1 receptors regulate the reinforcing and reward-enhancing effects of cocaine: pharmacological and behavioral genetics evidence.

Considerable evidence suggests that transmission at hypocretin-1 (orexin-1) receptors (Hcrt-R1) plays an important role in the reinstatement of extinguished cocaine-seeking behaviors in rodents. However, far less is known about the role for hypocretin transmission in regulating ongoing cocaine-taking behavior. Here, we investigated the effects of the selective Hcrt-R1 antagonist SB-334867 on cocaine intake, as measured by intravenous (IV) cocaine self-administration in rats. The stimulatory effects of cocaine on brain reward systems contribute to the establishment and maintenance of cocaine-taking behaviors. Therefore, we also assessed the effects of SB-334867 on the reward-enhancing properties of cocaine, as measured by cocaine-induced lowering of intracranial self-stimulation (ICSS) thresholds. Finally, to definitively establish a role for Hcrt-R1 in regulating cocaine intake, we assessed IV cocaine self-administration in Hcrt-R1 knockout mice. We found that SB-334867 (1-4 mg/kg) dose-dependently decreased cocaine (0.5 mg/kg/infusion) self-administration in rats but did not alter responding for food rewards under the same schedule of reinforcement. This suggests that SB-334867 decreased cocaine reinforcement without negatively impacting operant performance. SB-334867 (1-4 mg/kg) also dose-dependently attenuated the stimulatory effects of cocaine (10 mg/kg) on brain reward systems, as measured by reversal of cocaine-induced lowering of ICSS thresholds in rats. Finally, we found that Hcrt-R1 knockout mice self-administered far less cocaine than wildtype mice across the entire dose-response function. These data demonstrate that Hcrt-R1 play an important role in regulating the reinforcing and reward-enhancing properties of cocaine and suggest that hypocretin transmission is likely essential for establishing and maintaining the cocaine habit in human addicts

Magnetic structure of the field-induced multiferroic GdFe3(BO3)4

We report a magnetic x-ray scattering study of the field-induced multiferroic GdFe3(BO3)4. Resonant x-ray magnetic scattering at the Gd LII,III edges indicates that the Gd moments order at TN ~ 37 K. The magnetic structure is incommensurate below TN, with the incommensurability decreasing monotonically with decreasing temperature until a transition to a commensurate magnetic phase is observed at T ~ 10 K. Both the Gd and Fe moments undergo a spin reorientation transition at TSR ~ 9 K such that the moments are oriented along the crystallographic c axis at low temperatures. With magnetic field applied along the a axis, our measurements suggest that the field-induced polarization phase has a commensurate magnetic structure with Gd moments rotated ~45 degrees toward the basal plane, which is similar to the magnetic structure of the Gd subsystem observed in zero field between 9 and 10 K, and the Fe subsystem has a ferromagnetic component in the basal plane.Comment: 27 pages, 7 figures, to appear in Phys. Rev.

Modelling the atomic structure of very high-density amorphous ice

The structure of very high-density amorphous (VHDA) ice has been modelled by positionally disordering three crystalline phases, namely ice IV, VI and XII. These phases were chosen because only they are stable or metastable in the region of the ice phase diagram where VHDA ice is formed, and their densities are comparable to that of VHDA ice. An excellent fit to the medium range of the experimentally observed pair-correlation function g(r) of VHDA ice was obtained by introducing disorder into the positions of the H2O molecules, as well as small amounts of molecular rotational disorder, disorder in the O--H bond lengths and disorder in the H--O--H bond angles. The low-k behaviour of the experimental structure factor, S(k), is also very well reproduced by this disordered-crystal model. The fraction of each phase present in the best-fit disordered model is very close to that observed in the probable crystallization products of VHDA ice. In particular, only negligible amounts of ice IV are predicted, in accordance with experimental observation.Comment: 4 pages, 3 figures, 1 table, v2: changes made in response to referees' comments, the justification for using certain ice phases is improved, and ice IV is now disordered as wel

Estimating Maximal Symmetries of Regression Functions via Subgroup Lattices

We present a method for estimating the maximal symmetry of a regression function. Knowledge of such a symmetry can be used to significantly improve modelling by removing the modes of variation resulting from the symmetries. Symmetry estimation is carried out using hypothesis testing for invariance strategically over the subgroup lattice of a search group G acting on the feature space. We show that the estimation of the unique maximal invariant subgroup of G can be achieved by testing on only a finite portion of the subgroup lattice when G_max is a compact subgroup of G, even for infinite search groups and lattices (such as for the 3D rotation group SO(3)). We then show that the estimation is consistent when G is finite. We demonstrate the performance of this estimator in low dimensional simulations, on a synthetic image classification on MNIST data, and apply the methods to an application using satellite measurements of the earth's magnetic field.Comment: 35 Pages, 11 figure

Practices of strength and conditioning coaches: a snapshot from different sports, countries and expertise levels

This study describes the practices of strength and conditioning coaches (SCCs) from different sports, countries and expertise levels. One-hundred and fifty-six SCCs (31.9 + 8.9 years old) completed an online survey, consisting of 40 questions (36 fixed response and 4 open-ended), with eight sections: (a) background information, (b) muscular strength and power development, (c) speed development, (d) plyometrics, (e) flexibility development, (f) physical testing, (g) technology use, and (h) programming and any additional comments. Responses were received from 48 sports and 17 countries. This study provides exploratory evidence incorporating responses primarily in soccer (45%), track and field (30%), volleyball (23%), golf (17%) and tennis (17%). A Bachelor’s degree or higher were held by 99% of SCCs, of which 94% were in a sports science related field, and 71% held a strength and conditioning related certification or accreditation. Periodization strategies and physical testing were used by 94% of SCCs. The hang clean (82%), power clean (76%), and clean high pull (63%) were the most commonly prescribed Olympic Weightlifting exercises. Multiple hops/lunges (84%) were the most commonly prescribed plyometrics exercises. For open ended questions, 40% of SCCs wanted to integrate more technology into their programs, whereas, 30% of coaches believed technology will be the main future trend in strength and conditioning. SCCs from different sports, countries and expertise levels can use the information presented in this study to review their current practices and potentially provide a source of new ideas for diversifying or modifying future practices too

Dynamic detection of electron spin accumulation in ferromagnet-semiconductor devices by ferromagnetic resonance

A distinguishing feature of spin accumulation in ferromagnet-semiconductor devices is precession of the non-equilibrium spin population of the semiconductor in a magnetic field. This is the basis for detection techniques such as the Hanle effect, but these approaches become less effective as the spin lifetime in the semiconductor decreases. For this reason, no electrical Hanle measurement has been demonstrated in GaAs at room temperature. We show here that by forcing the magnetization in the ferromagnet (the spin injector and detector) to precess at the ferromagnetic resonance frequency, an electrically generated spin accumulation can be detected from 30 to 300 K. At low temperatures, the distinct Larmor precession of the spin accumulation in the semiconductor can be detected by ferromagnetic resonance in an oblique field. We verify the effectiveness of this new spin detection technique by comparing the injection bias and temperature dependence of the measured spin signal to the results obtained using traditional methods. We further show that this new approach enables a measurement of short spin lifetimes (< 100 psec), a regime that is not accessible in semiconductors using traditional Hanle techniques.Comment: 4 figure

Effects of continuing professional development on group work practices in Scottish primary schools

This study investigated the effects of a continuing professional development (CPD) initiative that provided collaborative group work skills training for primary school teachers. The study collected data from 24 primary school classrooms in different schools in a variety of urban and rural settings. The sample was composed of 332 pupils aged 9-12 years old, and 24 primary school teachers. Results indicated the CPD initiative had a significant impact on the attainment of pupils in science. In addition data indicated that the CPD promoted effective discourse and pupil dialogue during science lessons. Pre-post test observation scores were significantly different in terms of children giving of suggestions or courses of actions, offering of explanations, and telling someone to say something or carry out an action . Increases in effective dialogue were significantly correlated to increased science attainment and teacher evaluations of the impact of the CPD were positive. Significant correlations were found between teacher evaluation of impact upon pupil learning and increased attainment in science. The design and structure of CPD initiatives and the implications for practice, policy and future research are explored