Magnetooptic properties of self-trapped excitons in cesium halides

A model for the electronic structure of self-trapped excitons in Cs halides is proposed. By applying it, reasonable interpretations were obtained for the magnetic circular polarization (MCP) of the 2 intrinsic emissions in CsI, and for the MCP and EPR in CsBr

Optical detection of spin relaxation processes in the triplet state of the self trapped exciton in alkali halides

The transient response of the triplet self-trapped exciton luminescence intensity to a pulsed microwave excitation was measured for 1.3 K < T < 4.2 K in NaCl, KCl, RbCl, KBr, RbBr and CsBr. The results are quantitatively explained with a theoretical model describing the spin relaxation phenomena as 1-phonon direct processes. Good agreement was obtained as a function of temperature and magnetic field

Feasibility of quantum key distribution through dense wavelength division multiplexing network

In this paper, we study the feasibility of conducting quantum key distribution (QKD) together with classical communication through the same optical fiber by employing dense-wavelength-division-multiplexing (DWDM) technology at telecom wavelength. The impact of the classical channels to the quantum channel has been investigated for both QKD based on single photon detection and QKD based on homodyne detection. Our studies show that the latter can tolerate a much higher level of contamination from the classical channels than the former. This is because the local oscillator used in the homodyne detector acts as a "mode selector" which can suppress noise photons effectively. We have performed simulations based on both the decoy BB84 QKD protocol and the Gaussian modulated coherent state (GMCS) QKD protocol. While the former cannot tolerate even one classical channel (with a power of 0dBm), the latter can be multiplexed with 38 classical channels (0dBm power each channel) and still has a secure distance around 10km. Preliminary experiment has been conducted based on a 100MHz bandwidth homodyne detector.Comment: 18 pages, 5 figure

Agricultura orgânica em áreas urbanas e periurbanas com base na agroecologia.

A agricultura orgânica com base na agroecologia é o mote tecnológico adequado à realidade dos agroecossistemas urbanos. Este artigo ressalta a necessidade de se desenvolver tecnologias e insumos específicos. A partir de experiências com agricultura urbana em diferentes países em desenvolvimento, evidencia-se a necessidade de se buscar capacidades locais e apoio do poder público, especialmente nas iniciativas da sociedade organizada e mobilizada para a produção agrícola urbana

Insight from the draft genome of Dietzia cinnamea P4 reveals mechanisms of survival in complex tropical soil habitats and biotechnology potential

The draft genome of Dietzia cinnamea strain P4 was determined using pyrosequencing. In total, 428 supercontigs were obtained and analyzed. We here describe and interpret the main features of the draft genome. The genome contained a total of 3,555,295 bp, arranged in a single replicon with an average G+C percentage of 70.9%. It revealed the presence of complete pathways for basically all central metabolic routes. Also present were complete sets of genes for the glyoxalate and reductive carboxylate cycles. Autotrophic growth was suggested to occur by the presence of genes for aerobic CO oxidation, formate/formaldehyde oxidation, the reverse tricarboxylic acid cycle and the 3-hydropropionate cycle for CO2 fixation. Secondary metabolism was evidenced by the presence of genes for the biosynthesis of terpene compounds, frenolicin, nanaomycin and avilamycin A antibiotics. Furthermore, a probable role in azinomycin B synthesis, an important product with antitumor activity, was indicated. The complete alk operon for the degradation of n-alkanes was found to be present, as were clusters of genes for biphenyl ring dihydroxylation. This study brings new insights in the genetics and physiology of D. cinnamea P4, which is useful in biotechnology and bioremediation

Developmental and pathological lymphangiogenesis: from models to human disease.

The lymphatic vascular system, the body's second vascular system present in vertebrates, has emerged in recent years as a crucial player in normal and pathological processes. It participates in the maintenance of normal tissue fluid balance, the immune functions of cellular and antigen trafficking and absorption of fatty acids and lipid-soluble vitamins in the gut. Recent scientific discoveries have highlighted the role of lymphatic system in a number of pathologic conditions, including lymphedema, inflammatory diseases, and tumor metastasis. Development of genetically modified animal models, identification of lymphatic endothelial specific markers and regulators coupled with technological advances such as high-resolution imaging and genome-wide approaches have been instrumental in understanding the major steps controlling growth and remodeling of lymphatic vessels. This review highlights the recent insights and developments in the field of lymphatic vascular biology

Identification of a 120-kD surface glycoprotein distinguishing cultured superior cervical ganglion from ciliary ganglion neurons

Cell recognition during development of the nervous system involves specific interactions between neuronal cell surface molecules and their environment. Thus one type of neuron could carry on its surface a molecule which allows it to be distinguished from other types of neurons. We have tried to identify such specific components by comparing cell surfaces of cultured chick sympathetic (superior cervical ganglion) and parasympathetic (ciliary ganglion) neurons. Using metabolic labeling with (3H)-fucose or surface-labeling with the galactose oxidase-tritiated sodium borohydride method, we have identified a glycoprotein with an apparent molecular weight of 120 kD which is present on superior cervical ganglion neurons, but can barely be revealed on ciliary ganglion neurons. This molecule thus distinguishes two subsets of neurons and might therefore play a role in mediating specific interactions between the sympathetic neurons and their environment