Spin distillation cooling of ultracold Bose gases

We study the spin distillation of spinor gases of bosonic atoms and find two different mechanisms in $${}^{52}$$ 52 Cr and $$^{23}$$ 23 Na atoms, both of which can cool effectively. The first mechanism involves dipolar scattering into initially unoccupied spin states and cools only above a threshold magnetic field. The second proceeds via equilibrium relaxation of the thermal cloud into empty spin states, reducing its proportion in the initial component. It cools only below a threshold magnetic field. The technique was initially demonstrated experimentally for a chromium dipolar gas (Naylor et al. in Phys Rev Lett 115:243002, 2015), whereas here we develop the concept further and provide an in-depth understanding of the required physics and limitations involved. Through numerical simulations, we reveal the mechanisms involved and demonstrate that the spin distillation cycle can be repeated several times, each time resulting in a significant additional reduction of the thermal atom fraction. Threshold values of magnetic field and predictions for the achievable temperature are also identified.

STUDY OF THE CONDITIONS FOR THE ACQUISITION OF Tl3AsS4 IN ETHYLENE GLYCOL

The article presents the results of obtaining thallium thioarsenate in ethylene glycol medium and physicochemical analysis methods (XRD, DTG, TG and SEM). It was found that when ethylene glycol is used as a solvent and TlNO3 and As2S5 as the initial component, thallium thioarsenate is obtained at 353 K temperature. Thallium thioarsenate is formed by the interaction of TlNO3 and As2S5 at a ratio of 4:15 mol. After the compound was obtained at a temperature of 353 K (pH = 7-8), thermally processed at a temperature of 523-543 K, the melting point of the thallium thioarsenate sample has been 683 K. According to the results of thermogravimetric analysis, at temperatures above 733 K thallium thioarsenate decomposes in nitrogen gas environment. The micromorphology of the Tl3AsS4 compound obtained in the ethylene glycol medium was studied and it was determined that nanoparticles of the Tl3AsS4 compound are formed at a temperature of 353 K.

Component Resolved IR Bleaching Study of the Blue LM-OSL Signal of Various Quartz Samples

Component Resolved IR Bleaching Study of the Blue LM-OSL Signal of Various Quartz Samples The present work provides an initial component resolved analysis concerning the effect of infra-red (IR) exposure at elevated temperatures on the blue LM-OSL signal of quartz (stimulated at 470 nm). The study was performed on a total of seven quartz samples, among which five originated from Turkey, one from Greece and one synthetic quartz sample. For these quartz samples, the presence of 6 or even 7 independent LM-OSL components was previously reported, after the application of a computerized decomposition analysis. IR bleaching of each one of these components is studied and compared to the respective signal reduction due to the same thermal treatment solely. It is clearly demonstrated that IR stimulation at temperatures above 50°C does not deplete only the fast component in most sedimentary quartz samples studied. Net depletion of fast and medium components resulting from IR exposure is sample-dependent and occurs faster as the stimulation temperature increases. Weak IR bleaching of slow components is also reported in some cases, being more effective for stimulation temperatures up to 100°C. No depletion of either the medium or the slow components was detected for stimulation temperatures above 150°C. Finally, IR does not stimulate any of the LM-OSL components in the case of the synthetic quartz sample.

Ambiente y TLC: el pacto de gobernabilidad

This paper aims at providing, from a sustainable development perspective, an idea about the direction our country will take once the US-Peru FTA is enforced, regarding particularly the environmental, trade and investment areas. The signing of the FTA has led Peru to leave behind a view of the environment vision as a moral and ethical (some times marginal) component of economic relations, to turn it into a regulatory and mandatory consideration overlapping trade and investment to such an extent that failure to comply may lead to sanctions as severe as those pertaining to other matters related to for instance access to or permanence in a given market. Even so, it is worthwhile mentioning that the FTA is only an initial component of a more complex and broad multilateral scenario that recognizes in the environment an essential element of international economic relations.

Odor-Driven Activity in the Olfactory Cortex of an In Vitro Isolated Guinea Pig Whole Brain With Olfactory Epithelium

We developed a new technique to isolate a whole guinea pig brain with an intact olfactory epithelium (OE) that enables us to access the ventral surface of the brain including olfactory areas with ease during natural odor stimulation. We applied odorants to OE and confirmed that odor-induced local field potentials (LFPs) could be induced in olfactory areas. In the olfactory bulb (OB) and the piriform cortex (PC), odor-induced LFPs consisted of a phasic initial component followed by a fast activity oscillation in the beta range (20 Hz). To understand the neural mechanisms of odor-induced responses especially in the anterior PC, we analyzed odor-induced LFPs, together with unit activity data. We confirmed that the initial component of odor-induced response has a characteristic temporal pattern, generated by a relatively weak direct afferent input, followed by an intra-cortical associative response, which was associated with a phasic inhibition. The beta oscillation might be formed by the repetition of these network activities. These electrophysiological data were consistent with the results of previous studies that used slice or in vivo preparations, suggesting that the olfactory neural network and activities of the brain are preserved in our new in vitro preparation. This study provides the basis for clarifying the sequence of neural activities underlying odor information processing in the brain in vitro following natural olfactory stimulation.