Landau Theory of the Phase Transitions in Half Doped Manganites: Interplay of Magnetic, Charge and Structural Orders

The order parameters of the magnetic, charge and structural orders at half-doped manganites are identified. A corresponding Landau theory of the phase transitions is formulated. Many structural and thermodynamical behaviors are accounted for and clarified within the framework. In particular, the theory provides a unified picture for the scenario of the phase transitions and their nature with respect to the variation of the tolerance factor of the manganites. It also accounts for the origin of the incommensurate nature of the orbital order and its subsequently accompanying antiferromagnetic order.Comment: 4 pages, 3 eps figures, Revtex, Phys. Rev. B61, 200

High levels effects of vitamins A , D3 , E and C upon semen quality of bulls

Os efeitos de super dosagem de vitaminas A, D3, E e C sobre a qualidade do sêmen de 20 touros, 10 de origem europeia (Grupo I) e 10 de origem indiana (Grupo II), foram estudados visando a evitar seu declínio no período da seca. O experimento constou de três períodos: Preliminar, com duração de 6 semanas, Experimental (9 semanas) e Pós-experimental (9 semanas) com colheitas de sêmen semanais, utilizando-se vagina artificial para o Grupo I e eletroejaculação para o Grupo II. Durante todo o experimento os animais receberam 40.000 UI de vitamina A, 4.000 UI de vitamina D3 e 40mg de vitamina E contidos em 4kg de ração concentrada, por animal e por dia, além da forragem verde. No período experimental, cada animal recebeu, adicionalmente, 15ml de um complexo vitamínico A, D3 E C, que continha 50.000 UI de vitamina A, 5.000 UI de vitamina D3, 30mg de vitamina E e 1OOmg de vitamina C por ml. No total foram realizadas 480 colheitas de sêmen com seus respectivos espermogramas, analisando-se particularmente o volume de sêmen, motilidade, concentração espermática e formas patológicas, incluindo anormalidades do acrossomo, cabeça, inserção, peça intermediária, gotas citológicas, distais e presença de formas plasmáticas. Análise estatística aplicada aos resultados obtidos não foi capaz de revelar diferenças significativas, quanto à qualidade do sêmen, que se manteve praticamente inalterada antes, durante e depois da ministração do choque vitamínico. Esta ocorrência leva a supor que a suplementação de vitaminas A, D3 E e C para reprodutores bovinos no período da seca é desnecessária à produção de sêmen de boa qualidade, desde que os animais contém com teores adequados de vitaminas A, D3, E, na ração.  The purpose of this study was to determine the effect of high levels of vitamins A, D3, E and C upon semen quality of 20 bulls, 10 of European origin (group I) and 20 zebu bulls (group II) mainly during dry season. The trial had a 6 weeks preliminary step, an experimental period and a post-experimental period of 9 weeks each. Semen collections were made once a week, group I being collected with artificial vagina and group II by electroejaculation. Over 480 semen samples were collected from the 20 bulls. The animals were fed daily 4kg of a concentrate ration containing 40000 IU of vitamin A, 4000 IU of vitamin D3 and 40mg of vitamin E, besides grass. During the experimental period each animal received additionally “per os” 15ml of a vitamin A, D3,C complex, containing 50000 IU of vitamin A, 5000 IU of vitamin D3 , 30mg of vitamin E and 100mg of vitamin C per ml. Differences between periods were not significant regarding semen quality. It appears that the feeding of 15ml vitamin A D3, E, C Complex daily in addition to the normal ration did not increase the volume of semen produced by the bulls or the spermatozoa concentration in the semen, as so it did not improve the motility of the spermatozoa and did not change the per cent of abnormal spermatozoa

Social isolation disrupts hippocampal neurogenesis in young non-human primates

Social relationships are crucial for the development and maintenance of normal behavior in non-human primates. Animals that are raised in isolation develop abnormal patterns of behavior that persist even when they are later reunited with their parents. in rodents, social isolation is a stressful event and is associated with a decrease in hippocampal neurogenesis but considerably less is known about the effects of social isolation in non-human primates during the transition from adolescence to adulthood. To investigate how social isolation affects young marmosets, these were isolated from other members of the colony for 1 or 3 weeks and evaluated for alterations in their behavior and hippocampal cell proliferation. We found that anxiety-related behaviors like scent-marking and locomotor activity increased after social isolation when compared to baseline levels. in agreement, grooming an indicative of attenuation of tension was reduced among isolated marmosets. These results were consistent with increased cortisol levels after 1 and 3 weeks of isolation. After social isolation (1 or 3 weeks), reduced proliferation of neural cells in the subgranular zone of dentate granule cell layer was identified and a smaller proportion of BrdU-positive cells underwent neuronal fate (doublecortin labeling). Our data is consistent with the notion that social deprivation during the transition from adolescence to adulthood leads to stress and produces anxiety-like behaviors that in turn might affect neurogenesis and contribute to the deleterious consequences of prolonged stressful conditions.Universidade Federal de São Paulo, Dept Fisiol, BR-04023062 São Paulo, BrazilUniv Fed Rio Grande do Norte, Dept Fisiol, BR-59072970 Natal, RN, BrazilUniv Fed Rural Rio de Janeiro, Dept Ciencias Fisiol, Rio de Janeiro, BrazilUniversidade Federal de São Paulo, Dept Fisiol, BR-04023062 São Paulo, BrazilWeb of Scienc

Network Models: Action formulation

We develop a technique to formulate quantum field theory on arbitrary network, based on different, randomly disposed sets of scattering's. We define R-matrix of the whole network as a product of R-matrices attached to each of scattering nods. Then an action for a network in terms of fermionic fields is formulated, which allows to calculate the transition amplitudes as their Green functions. On so-called bubble and triangle diagrams it is shown that the method produces the same results as the one which uses the generalized star product. The approach allows to extend network models by including multiparticle interactions at the scattering nods.Comment: 27 pages, 9 figure

The SWELLS Survey. I. A large spectroscopically selected sample of edge-on late-type lens galaxies

The relative contribution of baryons and dark matter to the inner regions of spiral galaxies provides critical clues to their formation and evolution, but it is generally difficult to determine. For spiral galaxies that are strong gravitational lenses, however, the combination of lensing and kinematic observations can be used to break the disk-halo degeneracy. In turn, such data constrain fundamental parameters such as i) the mass density profile slope and axis ratio of the dark matter halo, and by comparison with dark matter-only numerical simulations the modifications imposed by baryons; ii) the mass in stars and therefore the overall star formation efficiency, and the amount of feedback; iii) by comparison with stellar population synthesis models, the normalization of the stellar initial mass function. In this first paper of a series, we present a sample of 16 secure, 1 probable, and 6 possible strong lensing spiral galaxies, for which multi-band high-resolution images and rotation curves were obtained using the Hubble Space Telescope and Keck-II Telescope as part of the Sloan WFC Edge-on Late-type Lens Survey (SWELLS). The sample includes 8 newly discovered secure systems. [abridged] We find that the SWELLS sample of secure lenses spans a broad range of morphologies (from lenticular to late-type spiral), spectral types (quantified by Halpha emission), and bulge to total stellar mass ratio (0.22-0.85), while being limited to M_*>10^{10.5} M_sun. The SWELLS sample is thus well-suited for exploring the relationship between dark and luminous matter in a broad range of galaxies. We find that the deflector galaxies obey the same size-mass relation as that of a comparison sample of elongated non-lens galaxies selected from the SDSS survey. We conclude that the SWELLS sample is consistent with being representative of the overall population of high-mass high-inclination disky galaxies.Comment: 21 pages, 6 figures, MNRAS, in pres

The background in the neutrinoless double beta decay experiment GERDA

The GERmanium Detector Array (GERDA) experiment at the Gran Sasso underground laboratory (LNGS) of INFN is searching for neutrinoless double beta decay of 76Ge. The signature of the signal is a monoenergetic peak at 2039 keV, the Q-value of the decay, Q_bb. To avoid bias in the signal search, the present analysis does not consider all those events, that fall in a 40 keV wide region centered around Q_bb. The main parameters needed for the neutrinoless double beta decay analysis are described. A background model was developed to describe the observed energy spectrum. The model contains several contributions, that are expected on the basis of material screening or that are established by the observation of characteristic structures in the energy spectrum. The model predicts a flat energy spectrum for the blinding window around Q_bb with a background index ranging from 17.6 to 23.8*10^{-3} counts/(keV kg yr). A part of the data not considered before has been used to test if the predictions of the background model are consistent. The observed number of events in this energy region is consistent with the background model. The background at Q-bb is dominated by close sources, mainly due to 42K, 214Bi, 228Th, 60Co and alpha emitting isotopes from the 226Ra decay chain. The individual fractions depend on the assumed locations of the contaminants. It is shown, that after removal of the known gamma peaks, the energy spectrum can be fitted in an energy range of 200 kev around Q_bb with a constant background. This gives a background index consistent with the full model and uncertainties of the same size

Grey and white matter correlates of recent and remote autobiographical memory retrieval:Insights from the dementias

The capacity to remember self-referential past events relies on the integrity of a distributed neural network. Controversy exists, however, regarding the involvement of specific brain structures for the retrieval of recently experienced versus more distant events. Here, we explored how characteristic patterns of atrophy in neurodegenerative disorders differentially disrupt remote versus recent autobiographical memory. Eleven behavioural-variant frontotemporal dementia, 10 semantic dementia, 15 Alzheimer's disease patients and 14 healthy older Controls completed the Autobiographical Interview. All patient groups displayed significant remote memory impairments relative to Controls. Similarly, recent period retrieval was significantly compromised in behavioural-variant frontotemporal dementia and Alzheimer's disease, yet semantic dementia patients scored in line with Controls. Voxel-based morphometry and diffusion tensor imaging analyses, for all participants combined, were conducted to investigate grey and white matter correlates of remote and recent autobiographical memory retrieval. Neural correlates common to both recent and remote time periods were identified, including the hippocampus, medial prefrontal, and frontopolar cortices, and the forceps minor and left hippocampal portion of the cingulum bundle. Regions exclusively implicated in each time period were also identified. The integrity of the anterior temporal cortices was related to the retrieval of remote memories, whereas the posterior cingulate cortex emerged as a structure significantly associated with recent autobiographical memory retrieval. This study represents the first investigation of the grey and white matter correlates of remote and recent autobiographical memory retrieval in neurodegenerative disorders. Our findings demonstrate the importance of core brain structures, including the medial prefrontal cortex and hippocampus, irrespective of time period, and point towards the contribution of discrete regions in mediating successful retrieval of distant versus recently experienced events

The NOD2-Smoking Interaction in Crohn's Disease is likely Specific to the 1007fs Mutation and may be Explained by Age at Diagnosis:A Meta-Analysis and Case-Only Study

Background: NOD2 and smoking are risk factors for Crohn's disease. We meta-analyzed NOD2-smoking interactions in Crohn's disease (Phase 1), then explored the effect of age at diagnosis on NOD2-smoking interactions (Phase 2). Methods: Phase 1: MEDLINE and EMBASE were searched for studies (n = 18) providing data on NOD2 and smoking in Crohn's disease. NOD2-smoking interactions were estimated using odds ratios (ORs) and 95% confidence intervals (CIs) calculated using random effects models. Phase 2: A case-only study compared the proportion of smokers and carriers of the 1007 fs variant across ages at diagnosis (≤16, 17–40, >40 years). Findings: Phase 1: Having ever smoked was less common among carriers of the 1007 fs variant of NOD2 (OR 0.74, 95%CI:0.66–0.83). There was no interaction between smoking and the G908R (OR 0.96, 95%CI:0.82–1.13) or the R702W variant (OR 0.89, 95%CI:0.76–1.05). Phase 2: The proportion of patients (n = 627) carrying the 1007 fs variant decreased with age at diagnosis (≤16 years: 15%; 17–40: 12%; >40: 3%; p = 0.003). Smoking was more common in older patients (≤16 years: 4%; 17–40: 48%; >40: 71%; p < 0.001). Interpretation: The negative NOD2-smoking interaction in Crohn's disease is specific to the 1007 fs variant. However, opposing rates of this variant and smoking across age at diagnosis may explain this negative interaction