2D layered transport properties from topological insulator Bi2_2Se3_3 single crystals and micro flakes

Low-field magnetotransport measurements of topological insulators such as Bi$_2$Se$_3$ are important for revealing the nature of topological surface states by quantum corrections to the conductivity, such as weak-antilocalization. Recently, a rich variety of high-field magnetotransport properties in the regime of high electron densities ($\sim10^{19}$ cm$^{-3}$) were reported, which can be related to additional two-dimensional layered conductivity, hampering the identification of the topological surface states. Here, we report that quantum corrections to the electronic conduction are dominated by the surface states for a semiconducting case, which can be analyzed by the Hikami-Larkin-Nagaoka model for two coupled surfaces in the case of strong spin-orbit interaction. However, in the metallic-like case this analysis fails and additional two-dimensional contributions need to be accounted for. Shubnikov-de Haas oscillations and quantized Hall resistance prove as strong indications for the two-dimensional layered metallic behavior. Temperature-dependent magnetotransport properties of high-quality Bi$_2$Se$_3$ single crystalline exfoliated macro and micro flakes are combined with high resolution transmission electron microscopy and energy-dispersive x-ray spectroscopy, confirming the structure and stoichiometry. Angle-resolved photoemission spectroscopy proves a single-Dirac-cone surface state and a well-defined bulk band gap in topological insulating state. Spatially resolved core-level photoelectron microscopy demonstrates the surface stability.Comment: Sci. Rep. (2016

On the volume of the set of mixed entangled states

A natural measure in the space of density matrices describing N-dimensional quantum systems is proposed. We study the probability P that a quantum state chosen randomly with respect to the natural measure is not entangled (is separable). We find analytical lower and upper bounds for this quantity. Numerical calculations give P = 0.632 for N=4 and P=0.384 for N=6, and indicate that P decreases exponentially with N. Analysis of a conditional measure of separability under the condition of fixed purity shows a clear dualism between purity and separability: entanglement is typical for pure states, while separability is connected with quantum mixtures. In particular, states of sufficiently low purity are necessarily separable.Comment: 10 pages in LaTex - RevTex + 4 figures in eps. submitted to Phys. Rev.

Dispersal within a spatially structured population of lesser kestrels: The role of spatial isolation and conspecific attraction

1. Factors governing dispersal rates have seldom been examined in spatially structured populations of vertebrates. We gathered information during 8 years on transfer rates between subpopulations in a spatially structured, growing population of colonial lesser kestrels Falco naumanni, and analysed the contribution of several variables related to spatial isolation and characteristics of both subpopulation of origin and destination on probabilities of dispersal. 2. Lesser kestrels were highly philopatric to their subpopulations, but first-breeders dispersed more often than adults (26% vs. 4%, n = 1706) because adults were reluctant to move from familiar areas. Frequency of subpopulation change was higher in females than in males (first-recruiters: 30% vs. 22%, n = 987; adults 5% vs. 1%, n = 719), according to their different breeding roles. However, all populational factors had an equal effect on individuals of different sex and dispersal status. 3. Movement rates decreased with inter-subpopulation distance - indicating that travelling to distant subpopulations may impose costs in terms of breeding prospects -and with the number of subpopulations, which increased during our study period. 4. Conspecific attraction strongly influenced the probability of dispersal: it was relatively higher in largely populated subpopulations, and individuals of large subpopulations were reluctant to change to others. These results were neither influenced by the size and breeding density of the subpopulations nor by habitat quality in terms of food availability or risk of predation, as indicated by breeding success of kestrels at each subpopulation. The number of conspecifics could be used by the kestrels as a cue of patch quality in terms of settlement options, and large subpopulations could be more easily detected by prospecting birds. 5. Our study highlights the fact that several assumptions of theoretical metapopulation modelling are often not fulfilled in nature. Both theoretical models and management strategies on spatially structured populations or metapopulations should thus consider the number, population size, and spatial distribution of local populations, as well as their relationships with the dispersal ability of the species.Peer Reviewe

Correction: The Endocytic Adaptor Eps15 Controls Marginal Zone B Cell Numbers.

Eps15 is an endocytic adaptor protein involved in clathrin and non-clathrin mediated endocytosis. In Caenorhabditis elegans and Drosophila melanogaster lack of Eps15 leads to defects in synaptic vesicle recycling and synapse formation. We generated Eps15-KO mice to investigate its function in mammals. Eps15-KO mice are born at the expected Mendelian ratio and are fertile. Using a large-scale phenotype screen covering more than 300 parameters correlated to human disease, we found that Eps15-KO mice did not show any sign of disease or neural deficits. Instead, altered blood parameters pointed to an immunological defect. By competitive bone marrow transplantation we demonstrated that Eps15-KO hematopoietic precursor cells were more efficient than the WT counterparts in repopulating B220⁺ bone marrow cells, CD19⁻ thymocytes and splenic marginal zone (MZ) B cells. Eps15-KO mice showed a 2-fold increase in MZ B cell numbers when compared with controls. Using reverse bone marrow transplantation, we found that Eps15 regulates MZ B cell numbers in a cell autonomous manner. FACS analysis showed that although MZ B cells were increased in Eps15-KO mice, transitional and pre-MZ B cell numbers were unaffected. The increase in MZ B cell numbers in Eps15 KO mice was not dependent on altered BCR signaling or Notch activity. In conclusion, in mammals, the endocytic adaptor protein Eps15 is a regulator of B-cell lymphopoiesis

Navigating Challenges in Interpreting Plant Physiology Responses through Gas Exchange Results in Stressed Plants

This paper explores the challenges that arise when performing and interpreting leaf gas exchange measurements in plants subjected to abiotic stress. It highlights how factors such as cuticular fluxes, stomatal closure, and common assumptions about gas exchange can lead to errors, especially under stress conditions. Key phenomena such as substomatal cavity unsaturation and stomatal patchiness during water stress are discussed in detail, as they significantly complicate the calculation of gas exchange parameters under stress. The paper also addresses the importance of other factors, including steady-state conditions, the differences between adaxial and abaxial surface responses, and boundary layer effects, all of which play critical roles in influencing the accuracy of measurements. Important physiological indicators—such as intrinsic water-use efficiency, minimum leaf conductance, substomatal CO2 concentration, and mesophyll conductance—are analysed in the context of how stress-induced discrepancies in data often result from measurement artefacts rather than true physiological differences. To address these challenges, the paper outlines practical approaches to improving measurement accuracy, offering insights on standardising experimental conditions and minimising errors. By recognising these issues, gaps in current knowledge are identified, providing a comprehensive overview of the challenges in interpreting leaf gas exchange data under stress conditions and suggesting areas for further study

Stoßwellenuntersuchungen zum Zerfall stickstoffhaltiger Verbindungen mit spektroskopischen Methoden

In dieser Arbeit wurden Geschwindigkeitskonstanten für den thermischen Zerfall von NCN und Allylamin unter verbrennungsrelevanten Bedingungen untersucht. Zerfallsreaktionen stickstoffhaltiger Verbindungen spielen zum Beispiel bei der Stickoxidbildung in Verbrennungsprozessen eine Rolle. Die Experimente wurden an einem Stoßrohr durchgeführt, an das ein ARAS-Aufbau oder ein FM-Spektrometer gekoppelt wurde. Die erhaltenen Ergebnisse wurden mit Hilfe der statistischen Reaktionstheorie analysiert

O cenário normativo do mercado de carbono no brasil e o potencial dos recursos naturais nacionais

Orientador: Dr. José Osório do Nascimento NetoTrabalho de Conclusão de Curso (Especialização) - Universidade Federal do Paraná, Setor de Ciências Agrárias, Curso de Especialização Direito Ambiental.Resumo: O presente trabalho teve como objetivo analisar a legislação do Mercado de Carbono, com vista a avaliar a capacidade dos recursos naturais do Brasil para estabelecer um Mercado consolidado. A partir desse estudo, foram identificadas as primeiras conferências da ONU, nos anos 1970, até a que se realizou em Paris (França) em dezembro de 2015, a COP 21, em que surge o Acordo de Paris. Foram levantadas informações acerca dos principais documentos (nacionais e internacionais) relacionados às mudanças climáticas, entendendo o que as normativas atuais oferecem para a melhor defesa dessas necessidades. Será feita uma breve análise sobre o setor florestal do Brasil, com especial destaque ao bioma da Amazônia e às populações tradicionais, que podem ser ferramenta para auxiliar a meta de redução de emissão de Gases de Efeito Estufa (GEE) no país e seus efeitos no aquecimento global

Supporting second language acquisition of bilingual preschool children through professionalization of caregivers in specialized preschool programs

The aim of the present study was to investigate the effectiveness of a training program on language support strategies and dialogic reading for caregivers working in specialized preschool programs. These programs serve children without a regular childcare place who grow up with one or more languages other than German as the environmental language. Recent studies investigating the development of children attending these programs found only moderate improvements in German receptive language skills, while language support quality of the programs was rated as average. We assessed receptive second language competencies in vocabulary and grammar of n = 48 children and language support competencies of n = 15 caregivers using an interventional pre-posttest design. Receptive vocabulary skills of children supported by trained caregivers (intervention group) were compared to children supported by untrained caregivers (control group, n = 43). We found that both children’s and caregivers’ competencies increased from pre- to posttest, whereas the control group’s receptive vocabulary skills did not increase noticeably. The caregivers’ language support competencies influenced the increase of children’s receptive grammar but not vocabulary skills. The comparison between the intervention group and control group consistently showed no effect of group membership on children’s receptive vocabulary acquisition over time. Since the control group data came from a secondary analysis, only receptive vocabulary skills could be compared. The preliminary results of our study suggest that a caregivers’ training on language support strategies and dialogic reading in everyday educational situations support bilingual children’s grammar acquisition

SmartFluo: A Method and Affordable Adapter to Measure Chlorophyll a Fluorescence with Smartphones

In order to increase the monitoring capabilities of inland and coastal waters, there is a need for new, affordable, sensitive and mobile instruments that could be operated semi-automatically in the field. This paper presents a prototype device to measure chlorophyll a fluorescence: the SmartFluo. The device is a combination of a smartphone offering an intuitive operation interface and an adapter implying a cuvette holder, as well as a suitable illumination source. SmartFluo is based on stimulated fluorescence of water constituents such as chlorophyll a. The red band of the digital smartphone camera is sensitive enough to detect quantitatively the characteristic red fluorescence emission. The adapter contains a light source, a strong light emitting diode and additional filters to enhance the signal-to-noise ratio and to suppress the impact of scattering. A novel algorithm utilizing the red band of the camera is provided. Laboratory experiments of the SmartFluo show a linear correlation (R 2 = 0.98) to the chlorophyll a concentrations measured by reference instruments, such as a high-performance benchtop laboratory fluorometer (LS 55, PerkinElmer)