Enhancement of the Hall-Lorenz number in optimally doped YBa2Cu3O_7-d

Electronic heat transport in the normal state of a high-quality single crystal of optimally-doped superconductor YBa2Cu3O6.95 was studied by measurements of longitudinal and transverse transport coefficients. For the temperature range from 100 to 300 K, the Hall-Lorenz number (Lxy) depends weakly on temperature and is about two times larger than the Sommerfeld value of the Lorenz number Lo = (pi^2)/3. Our results can be interpreted using a Fermi liquid model when effects of the pseudogap that opens at the Fermi level are included. However, we find that the bipolaron model can also explain both the enhanced value and the weak temperature dependence of the Hall-Lorenz number.Comment: Accepted for publication in Europhysics Letters; 16 pages, 2 figure

Gründer- und Technologiezentren in Polen 1997

Die mittel- und osteuropäischen Länder, darunter Polen, suchen seit der wirtschaftspolitischen Wende den Anschluß an die Weltwirtschaft und unternehmen Anstrengungen, ihre Volkswirtschaften dem strengen internationalen Wettbewerb anzupassen. Es zeigt sich am Beispiel Polens, daß sich im Zuge der Annäherung an die EU die bisherigen Vorteile der niedrigen Produktionskosten verringern. Das Wirtschaftswachstum des Landes wird zunehmend von der Innovationsfähigkeit der Unternehmen, der Modernisierung und von dem technischen Fortschritt abhängig. Um den technischen Fortschritt zu fördern, greift man in Polen auf die Einrichtung der Technologie- und Gründerzentren zurück. Wie die vorliegende Studie zeigt, spielen diese Zentren für die Gesamtentwicklung in Polen noch, eine geringe Rolle. Die von den Technologie- und Gründerzentren ausgehenden Technologieimpulse sind zur Zeit noch bescheiden, da oft bei der Einrichtung dieser Zentren die arbeitsmarktpolitischen Kriterien (Arbeitslosigkeitsbekämpfung) im Vordergrund stehen. --

Association between body condition and production parameters of dairy cows in the experiment with use of BCS camera

Dairy production effectiveness in the farm depends on many technical, technological and biological factors. State of the dairy cow condition constitutes one of the most important element in the assessment of dairy herd and production indices. Including access to modern technical solution to assess body condition of dairy cows, i.e. BCS camera, some results of observation in the herd with 362 cows were collected to find any relationship between BCS index and milk yield per cow including 5 lactation groups and cows differed in age as well as four seasons. Basing on data collected in the period of 11 months it was found that cows with the BCS index lower than 2.9 showed the highest daily milk production. Increase in BCS index was associated with decrease in amount of produced milk per day. The statistical analysis showed significant effect of lactation period, age of animals and season on BCS results in the considered dairy cow production cycle

The Impact of a 48-Hour Fast on Mitochondrial Biogenesis in Young Healthy Men

Please view abstract in the attached PDF fil

Nernst effect of iron pnictide and cuprate superconductors: signatures of spin density wave and stripe order

The Nernst effect has recently proven a sensitive probe for detecting unusual normal state properties of unconventional superconductors. In particular, it may sensitively detect Fermi surface reconstructions which are connected to a charge or spin density wave (SDW) ordered state, and even fluctuating forms of such a state. Here we summarize recent results for the Nernst effect of the iron pnictide superconductor $\rm LaO_{1-x}F_xFeAs$, whose ground state evolves upon doping from an itinerant SDW to a superconducting state, and the cuprate superconductor $\rm La_{1.8-x}Eu_{0.2}Sr_xCuO_4$ which exhibits static stripe order as a ground state competing with the superconductivity. In $\rm LaO_{1-x}F_xFeAs$, the SDW order leads to a huge Nernst response, which allows to detect even fluctuating SDW precursors at superconducting doping levels where long range SDW order is suppressed. This is in contrast to the impact of stripe order on the normal state Nernst effect in $\rm La_{1.8-x}Eu_{0.2}Sr_xCuO_4$. Here, though signatures of the stripe order are detectable in the temperature dependence of the Nernst coefficient, its overall temperature dependence is very similar to that of $\rm La_{2-x}Sr_xCuO_4$, where stripe order is absent. The anomalies which are induced by the stripe order are very subtle and the enhancement of the Nernst response due to static stripe order in $\rm La_{1.8-x}Eu_{0.2}Sr_xCuO_4$ as compared to that of the pseudogap phase in $\rm La_{2-x}Sr_xCuO_4$, if any, is very small.Comment: To appear in: 'Properties and applications of thermoelectric materials - II', V. Zlatic and A. Hewson, editors, Proceedings of NATO Advanced Research Workshop, Hvar, Croatia, September 19 -25, 2011, NATO Science for Peace and Security Series B: Physics and Biophysics, (Springer Science+Business Media B.V. 2012

Daylight: What Makes a Difference

Light is necessary for vision; it enables us to sense and perceive our surroundings and in many direct and indirect ways, via eye and skin, affects our physiological and psychological health. The use of light in built environments has comfort, behavioural, economic and environmental consequences. Daylight has many particular benefits including excellent visual performance, permitting good eyesight, effective entrainment of the circadian system as well as a number of acute non-image forming effects and the important role of vitamin D production. Some human responses to daylight seem to be well defined whilst others require more research to be adequately understood. This paper presents an overview of current knowledge on how the characteristics of daylight play a role in fulfilling these and other functions often better than electric lighting as conventionally delivered

Lighting conditions in home office and occupant's perception: Exploring drivers of satisfaction

This paper depicts lighting home office conditions within different countries and continents, emphasizing the user's satisfaction with the visual environment. The scope of this article is to investigate the drivers of participants' satisfaction with the lighting conditions at the home office. The study was developed by a team of international experts working together on Subtask A: User perspective and requirements, Task 61 IEA (International Energy Agency): Solutions for daylighting and electric lighting. An online survey was launched in December 2020 and closed on March 2021. The survey was implemented in the native languages of six participant countries (Brazil, Colombia, Denmark, Italy, Poland, and Japan) using Google Forms, and its dissemination was via various social media platforms. Measures of association between variables and predictive tests were run to explore which investigated aspects drove participants' satisfaction with the lighting conditions at the home office. We found some differences in satisfaction due to participants' sex, occupation, and participants' continent of residence. Females were more satisfied with daylight than males. Associations between the perception of seven light descriptors and satisfaction showed differences between East Asians and the rest of the participants, which might be related to the high dependence of the formers on electric lighting even when daylight is available. Design features as southern facades, the distance from the working area to the window, type of internal sun shading were related to daylighting satisfaction. Moreover, satisfaction with the general light level and the electric light was higher for those participants who did not need to switch on the ceiling, floor, or desk lamp when daylight was available. We found that an external view composed of 3 layers and the sky's visibility afforded a higher satisfaction with the window view. Having an independent room for the home office appeared to be related to a higher willingness to continue in the home office. Likewise, higher satisfaction with the overall visual environment and window view appeared to increase the willingness to continue working from home. Bridging the gap amid cultural differences and daylighting and lighting satisfaction is needed, particularly, relational studies between design features –as a response of cultural, climatic, and local practices- and occupants' preferences and acceptability. Thus, our understanding of occupants' responses will be more comprehensive. Engaging further research and measures to improve the visual environment and overall indoor environmental quality in dwellings is now a necessary step