1000 resultados para ddc: N3983


Relevância:

10.00% 10.00%

Publicador:

Resumo:

Finding equilibration times is a major unsolved problem in physics with few analytical results. Here we look at equilibration times for quantum gases of bosons and fermions in the regime of negligibly weak interactions, a setting which not only includes paradigmatic systems such as gases confined to boxes, but also Luttinger liquids and the free superfluid Hubbard model. To do this, we focus on two classes of measurements: (i) coarse-grained observables, such as the number of particles in a region of space, and (ii) few-mode measurements, such as phase correlators.Weshow that, in this setting, equilibration occurs quite generally despite the fact that the particles are not interacting. Furthermore, for coarse-grained measurements the timescale is generally at most polynomial in the number of particles N, which is much faster than previous general upper bounds, which were exponential in N. For local measurements on lattice systems, the timescale is typically linear in the number of lattice sites. In fact, for one-dimensional lattices, the scaling is generally linear in the length of the lattice, which is optimal. Additionally, we look at a few specific examples, one of which consists ofNfermions initially confined on one side of a partition in a box. The partition is removed and the fermions equilibrate extremely quickly in time O(1 N).

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Die Radiosendung Panoptikum Bildung versteht sich als Medium kritischer Berichterstattung und versucht sozialpolitische Phänomene durch sachliche Informationen aufzubereiten. Die einzelnen Radiobeiträge beleuchten bildungsrelevante Themen aus einem kritischen Blickwinkel, bieten umfassende Hintergrundinformationen und binden FachexpertInnen mit ein. Credo ist: Information statt Infotainment, Gespräch statt Floskeln, Wissensvermittlung anstelle von Talkshowformaten und Dialog statt Konfrontation. In diesem Beitrag, der sich auf bisher unveröffentlichte Jahresberichte der Radiosendereihe stützt, werden das Entstehen und die Leitgedanken sowie die Inhalte und Anliegen einzelner Radiobeiträge vor dem Hintergrund von Oskar Negts theoretischen Überlegungen zu Demokratie und Bildung beschrieben und reflektiert. (DIPF/Orig.)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

ABP1 and TIR1/AFBs are known as auxin receptors. ABP1 is linked to auxin responses several of which are faster than 10 min. TIR1 regulates auxin-induced transcription of early auxin genes also within minutes. We use transcription of such TIR1-dependent genes as indicator of TIR1 activity to show the rapid regulation of TIR1 by exogenous auxin. To this end, we used quantification of transcription of a set of fifteen early auxin-induced reporter genes at t = 10 and t = 30 min to measure this as a TIR1-dependent auxin response. We conducted this study in 22 mutants of auxin transporters (pin5, abcb1, abcb19, and aux1/lax3), protein kinases and phosphatases (ibr5, npr1, cpk3, CPK3-OX, d6pk1, d6pkl1-1, d6pkl3-2, d6pkl1-1/d6pkl2-2, and d6pkl1-1/d6pkl3-2), of fatty acid metabolism (fad2-1, fad6-1, ssi2, lacs4, lacs9, and lacs4/lacs9) and receptors (tir1, tir1/afb2, and tir1/afb3) and compared them to the wild type. After 10 min auxin application, in 18 out of 22 mutants mis-regulated expression of at least one reporter was found, and in 15 mutants transcription of two-to-three out of five selected auxin reporter genes was mis-regulated. After 30 min of auxin application to mutant plants, mis-regulation of reporter genes ranged from one to 13 out of 15 tested reporter genes. Those genes chosen as mutants were themselves not regulated in their expression by auxin for at least 1 h, excluding an influence of TIR1/AFBs on their transcription. The expression of TIR1/AFB genes was also not modulated by auxin for up to 3 h. Together, this excludes a feedback or feedforward of these mutant genes/proteins on TIR1/AFBs output of transcription in this auxin-induced response. However, an auxin-induced response needed an as yet unknown auxin receptor. We suggest that the auxin receptor necessary for the fast auxin-induced transcription modulation could be, instead, ABP1. The alternative hypothesis would be that auxin-induced expression of a protein, initiated by TIR1/AFBs receptors, could initiate these responses and that this unknown protein regulated TIR1/AFB activities within 10 min.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Wie kann in Seminaren zu Genderkompetenz Offenheit erzeugt werden, wenn die Teilnehmenden sich nicht freiwillig für den Besuch entschieden haben und daher mit Desinteresse oder Widerwillen reagieren? Der vorliegende Beitrag beschreibt ein didaktisches Vorgehen, das den persönlichen Widerstand von Teilnehmenden aufzulösen vermag und letztlich ein Problembewusstsein für soziale Ungleichheit initiiert. Zentral sind hierfür die Reflexion persönlicher Erfahrungen und ideologischer Diskussionen, die Ungleichheitsthemen meist mit sich bringen. Das vorgestellte didaktische Vorgehen im Gender Training, das u.a. Kompetenzerwartungen an Führungskräfte im Bildungsbereich entlang Geschlechterstereotypien aufdeckt, ist auch für andere Themen der politischen Bildung einsetzbar. Um also ein politisches Bewusstsein über Hierarchisierungs- und Diskriminierungsprozesse zu befördern, ist es wichtig, Ausschließungsprozesse im Alltag erlebbar zu machen und zu erkennen, wer vom Ausschluss anderer profitiert, wer die Ausschlusskriterien festlegt und dass unterschiedliche Kriterien dafür geeignet sind. (DIPF/Orig.)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

BACKGROUND: Smoking is a major risk factor for chronic obstructive pulmonary disease (COPD). For current smokers who are diagnosed with COPD, their first treatment option is to stop smoking. Motivation is necessary for long-term smoking cessation; therefore, when designing smoking cessation programs, the patients' needs and preferences should be considered. We focused on COPD patients' experiences with existing smoking cessation programs and evaluated their preferences for the improvement of these programs. METHODS: We conducted 18 guideline-based interviews with COPD patients between April and June 2014 in Germany. Each patient with COPD, who was a current or past smoker and had made at least one attempt to quit smoking in the past 5 years, was included in the study. We audiotaped, verbatim transcribed, and evaluated the interviews, using content analysis. RESULTS: The patients had broad and different experiences with pharmaceutical, behavioral, and alternative approaches that supported or negatively influenced the smoking cessation process. Pharmaceuticals were viewed as an expensive alternative with many side effects although they helped to stop cravings for a few moments. Furthermore, the bad structure and impersonal content of the seminars for smoking cessation negatively influenced group cohesion, and therefore degrading the patients' motivation to stop smoking. Alternative methods, such as acupuncture and hypnosis were mostly ineffective in smoking cessation, but in some cases, served as motivational strategies. CONCLUSION: Negative experiences with smoking cessation were explained by the patients' lack of motivation or resolution. Other negative experiences, such as the structure of seminars for smoking cessation and the high price of pharmaceuticals should be addressed through policy changes to increase the patients' motivation to quit smoking.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Facing widespread poverty and land degradation, Vietnam started a land reform in 1993 as part of its renovation policy package known as “Doi Moi”. This paper examines the impacts of improved land tenure security, via this land reform, on manure use by farm households. As manure potentially improves soil fertility by adding organic matter and nutrients to the soil surface, it might contribute to improving soil productive capacity and reversing land degradation. Random effect regression models are applied to a panel dataset of 133 farm households in the Northern Uplands of Vietnam collected in 1993, 1998, and 2006. The results confirm that land tenure security has positive effects on manure use, but the levels of influence differ depending on whether the land has been privatized or whether the land title has already been issued. In addition, manure use is also influenced by the number of cattle and pigs, the education level and ethnicity of household heads, farm land size and non-farm income. The findings suggest that speeding up land privatization and titling, encouraging cattle and pig rearing, and improving education would promote manure use in farm production. However, careful interpretation of our research findings is required as land privatization, together with economic growth and population pressure, might lead to overuse of farm inputs.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Die Expertise für den 13. Kinder- und Jugendbericht gibt einen Überblick über Versorgungsstrukturen und Inanspruchnahme bei psychischen Störungen von Kindern und Jugendlichen. Insbesondere werden auf der Basis einer aktuellen empirischen Untersuchung „gesundheitsbezogene Anlässe“ bei der Inanspruchnahme von Erziehungsberatung beschrieben. Ein eigenes Thema bildet die ICD-10-Kategorisierbarkeit von Problemen in der Erziehungsberatung. Dabei wird der diagnostische und therapeutische Ansatz der Erziehungsberatung in Abgrenzung zur Kinder- und Jugendpsychiatrie dargestellt. Auf der Grundlage der genannten Untersuchung werden schließlich die einzelfallbezogene und die einzelfallübergreifende Zusammenarbeit der Erziehungsberatung mit dem Gesundheitswesen beschrieben. Abschließend wird die Entwicklung der Erziehungsberatung in den letzten Jahren nach Inanspruchnahme, Personal und Kosten skizziert.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Drug delivery systems are defined as formulations aiming for transportation of a drug to the desired area of action within the body. The basic component of drug delivery systems is an appropriate carrier that protects the drug from rapid degradation or clearance and thereby enhances drug concentration in target tissues. Based on their biodegradable, biocompatible, and nonimmunogenic structure, niosomes are promising drug carriers that are formed by self-association of nonionic surfactants and cholesterol in an aqueous phase. In recent years, numerous research articles have been published in scientific journals reporting the potential of niosomes to serve as a carrier for the delivery of different types of drugs. The present review describes preparation methods, characterization techniques, and recent studies on niosomal drug delivery systems and also gives up to date information regarding recent applications of niosomes in drug delivery.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This report investigates adaptations of electronic packaging methods used to create stacks of these sensors. Four methods were developed and tested to determine the best option in terms of mechanical stability and electrical conductivity of the system. For the first method, a stack is created by way of through paper vias (TPVs), a hole that is cut in the pads of the sensors and then filled with electrically conductive adhesive through the openings on the two sensors to be joined. The second method is called mechanical caulking and connects sensors through pads which have been lined with copper tape backed with conductive adhesive. The connection is created with a small copper rivet which is flattened in place by compressive force. The third method is the stitching method which is inspired by sewing of fabric. A pattern of thin copper wire is stitched on the pad of a sensor that is lined with copper tape backed with conductive adhesive. The wire is then stitched through a second sensor that is treated similarly with copper tape and the stack receives the same pattern through the two layers as was applied to the first sensor alone. The final method is the collapsed daisy chain which is the linear connection of sensors to their neighboring sensors via copper tape backed with conductive adhesive. The row of sensors is then collapsed in an alternating orientation into a single stack.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The accurate prediction of stress histories for the fatigue analysis is of utmost importance for the design process of wind turbine rotor blades. As detailed, transient, and geometrically non-linear three-dimensional finite element analyses are computationally weigh too expensive, it is commonly regarded sufficient to calculate the stresses with a geometrically linear analysis and superimpose different stress states in order to obtain the complete stress histories. In order to quantify the error from geometrically linear simulations for the calculation of stress histories and to verify the practical applicability of the superposition principal in fatigue analyses, this paper studies the influence of geometric non-linearity in the example of a trailing edge bond line, as this subcomponent suffers from high strains in span-wise direction. The blade under consideration is that of the IWES IWT-7.5-164 reference wind turbine. From turbine simulations the highest edgewise loading scenario from the fatigue load cases is used as the reference. A 3D finite element model of the blade is created and the bond line fatigue assessment is performed according to the GL certification guidelines in its 2010 edition, and in comparison to the latest DNV GL standard from end of 2015. The results show a significant difference between the geometrically linear and non-linear stress analyses when the bending moments are approximated via a corresponding external loading, especially in case of the 2010 GL certification guidelines. This finding emphasizes the demand to reconsider the application of the superposition principal in fatigue analyses of modern flexible rotor blades, where geometrical nonlinearities become significant. In addition, a new load application methodology is introduced that reduces the geometrically non-linear behaviour of the blade in the finite element analysis.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Wie wird Geschlecht von Studierenden der Erziehungs- und Bildungswissenschaften rezipiert? Wie stehen die Studierenden zu Geschlechterfragen? Ausgehend von der Beobachtung, dass das Interesse an Geschlechterfragen zum Teil als individuelle, zudem etwas anachronistische Neigung erscheint, rekonstruiert diese empirische Studie u.a., welchen Einfluss das Studium des spezifischen Fachgebietes auf die Studierenden hat. Zudem wird deutlich, dass die studentische (De-)Thematisierung von Geschlecht auch maßgeblich von rhetorischen Modernisierungsprozessen und gesellschaftlichen Verdeckungszusammenhängen beeinflusst wird. (DIPF/Verlag)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Silver nanoparticles are widely used for many applications. In this study silver nanoparticles have been tested for their toxic effect on fibroblasts (NIH-3T3), on a human lung adenocarcinoma epithelial cell line (A-549), on PC-12-cells, a rat adrenal pheochromocytoma cell line, and on HEP-G2-cells, a human hepatocellular carcinoma cell line. The viability of the cells cultivated with different concentrations of silver was determined by the MTT assay, a photometric method to determine cell metabolism. Dose-response curves were extrapolated and IC50, total lethal concentration (TLC), and no observable adverse effect concentration (NOAEC) values were calculated for each cell line. As another approach, ECIS (electric-cell-substrate-impedance-sensing) an automated method to monitor cellular behavior in real-time was applied to observe cells cultivated with silver nanoparticles. To identify the type of cell death the membrane integrity was analyzed by measurements of the lactate dehydrogenase releases and by determination of the caspase 3/7 activity. To ensure that the cytotoxic effect of silver nanoparticles is not traced back to the presence of Ag+ ions in the suspension, an Ag+ salt (AgNO3) has been examined at the same concentration of Ag+ present in the silver nanoparticle suspension that is assuming that the Ag particles are completely available as Ag+ ions.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Sterben und Tod bedeuten meist das Hindurchgehen durch eine schwere Zeit sowohl für den Betroffenen selbst als auch für dessen Familienangehörige und Freunde. Umso wichtiger ist es, diesen Weg nicht alleine gehen zu müssen und dadurch Trost zu finden, dass in der Begleitung eine lebensstärkende Hoffnung zum Ausdruck kommt. Der vorliegende Band zum Thema Sterben, Tod und Trauer versammelt Beiträge aus unterschiedlichen fachlichen und beruflichen Perspektiven. Dabei wird die Soziale Arbeit als Bindeglied zwischen den unterschiedlichen Disziplinen herausgearbeitet. Das Buch macht deutlich, das Sterben und Trauern nicht nur mit großen Belastungen verbunden sind, sondern auch Chancen zu Integrität, Erkenntnis und persönlichem Wachstum eröffnen. Eine ganzheitliche, an den Bedürfnissen der Betroffenen orientierte Wegbegleitung von Haupt- und Ehrenamtlichen kann hierbei eine wichtige Hilfe darstellen. (DIPF/Orig.)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Research in solar energy conversion and the associated photoactive materials has attracted continuous interest. Due to its proper electronic band structure, high quantum efficiency, and photonic and chemical innerness, TiO2 has been demonstrated as a versatile oxide semiconductor capable of efficiently utilizing sunlight to produce electrical and chemical energy. Its outstanding physicochemical performances have led to an array of advanced photocatalytic and photoelectrochemical applications including environmental photocatalysis, dye/semiconductor-sensitized solar cell, and solar fuel productions.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The multiwall carbon nanotubes (MWCNTs)/titanium dioxide (P25) composite in different ratios was prepared using simple evaporation and drying process. The composite was characterized by Raman spectroscopy, X-ray diffraction (XRD), UV-visible diffuse reflectance spectroscopy, and scanning electron microscopy (SEM). The photocatalytic activity of this composite was investigated using degradation of the Bismarck brown R dye (BBR). An optimal MWCNTs/TiO2 ratio of 0.5% (w/w) was found to achieve the maximum rate of BBR degradation. It was observed that the composite exhibits enhanced photocatalytic activity compared with TiO2. The enhancement in photocatalytic activity performance of the MWCNTs/P25 composite is explained in terms of recombination of photogenerated electron-hole pairs. In addition, MWCNTs act as a dispersing support to control the morphology of TiO2 particles in the MWCNTs/TiO2 composite.