Spin-glass behavior in a three-dimensional antiferromagnet ordered phase: Magnetic structure of Co-2(OH)(PO4)

Co-2(OH)(PO4) has been prepared from hydrothermal synthesis and characterized from powder x-ray diffraction. The nuclear and magnetic structures have been determined by neutron (D2B and D1B) diffraction data. The structure consists of a three-dimensional framework in which Co(1)O-5-trigonal bipyramid dimers and Co(2)O-6-octahedra chains are simultaneously present. The EPR spectrum of Zn-2(OH)(PO4):0.1%Co at 4.2 K shows a strong anisotropy of the g factor. The values obtained for the g tensor and the hyperfine coupling constants for the octahedral symmetry were g(1)=5.890, g(2)=4.550, and g(3)=2.021 and A(1)=240x10(-4) cm(-1), A(2)=155x10(-4) cm(-1), and A(3)=85x10(-4) cm(-1). Signals corresponding to the five-coordinated Co(II) ions were also observed. Magnetization measurements show the presence of two maxima at circa 75 and 15 K, respectively. The first peak was attributed to a three-dimensional antiferromagnetic ordering and the second one reveals the existence of a spin-glass-like state. This state with a cooperative freezing was also confirmed by both ac susceptibility measurements and magnetic irreversibility observed in the zero-field-cooled-field-cooled signals. From low-temperature neutron-diffraction data, antiferromagnetic ordering is established with an ordering temperature of 71 K. The propagation vector of the magnetic structure is k=[0,0,0]. The magnetic moments at 1.7 K are ferromagnetically coupled between CoO6-octahedra chains and the Co2O10 dimers in the z direction. The values obtained for the magnetic moments are: 3.39(7)mu(B) [Co(1)] and 3.84(5)mu(B) [Co(2)]. The absence of any anomaly in both the specific heat and thermal evolution of the magnetic moments below similar to20 K confirms the blocking process of a spin glass behavior. The crystal-field splitting of the Co2+ ions causes a single ion anisotropy along the z (c-axis) direction, giving an Ising character in which the local spins from the Co(1) dimers are frozen. A magnetic frustration in the Co(1) magnetic moments is observed as due to the presence of antiferromagnetic interactions between Co(2) neighbor chains. It is to note the existence of a Co(1)-O(3)(PO3)-Co(2) superexchange angle with a value of 107degrees that involves ferromagnetic couplings between chain and dimer neighbors ferromagnetically coupled. This exchange pathway together with the anisotropy and frustration could be the responsible of the spin glass behavior observed in the three-dimensional antiferromagnetic Co-2(OH)(PO4) ordered phase.66

MHC class I loci of the Bar-Headed goose (Anser indicus)

MHC class I proteins mediate functions in anti-pathogen defense. MHC diversity has already been investigated by many studies in model avian species, but here we chose the bar-headed goose, a worldwide migrant bird, as a non-model avian species. Sequences from exons encoding the peptide-binding region (PBR) of MHC class I molecules were isolated from liver genomic DNA, to investigate variation in these genes. These are the first MHC class I partial sequences of the bar-headed goose to be reported. A preliminary analysis suggests the presence of at least four MHC class I genes, which share great similarity with those of the goose and duck. A phylogenetic analysis of bar-headed goose, goose and duck MHC class I sequences using the NJ method supports the idea that they all cluster within the anseriforms clade

Comparative cytogenetic analysis of two grasshopper species of the tribe Abracrini (Ommatolampinae, Acrididae)

The grasshopper species Orthoscapheus rufipes and Eujivarus fusiformis were analyzed using several cytogenetic techniques. The karyotype of O. rufipes, described here for the first time, had a diploid number of 2n = 23, whereas E. fusiformis had a karyotype with 2n = 21. The two species showed the same mechanism of sex determination (XO type) but differed in chromosome morphology. Pericentromeric blocks of constitutive heterochromatin (CH) were detected in the chromosome complement of both species. CMA3/DA/DAPI staining revealed CMA3-positive blocks in CH regions in four autosomal bivalents of O. rufipes and in two of E. fusiformis. The location of active NORs differed between the two species, occurring in bivalents M6 and S9 of O. rufipes and M6 and M7 of E. fusiformsi. The rDNA sites revealed by FISH coincided with the number and position of the active NORs detected by AgNO3 staining. The variability in chromosomal markers accounted for the karyotype differentiation observed in the tribe Abracrini

Communication for Peaceful Social Change and Global Citizenry

The adoption of the 17 Sustainable Development Goals (SDGs) by the United Nations (UN) in 2015 represents a universal call to action involving multiple international actors for the purpose of eradicating poverty, improving living conditions and promoting peace. This entry provides a theoretical overview of the contributions of scholars and practitioners who highlight the importance of a transformative, educational and emancipatory communication by different social actors to establish the main lines of action for the 2030 Agenda for Sustainable Development. This communicative model involves the coordination of actors and strategies, both short- and long-term, cross-cutting actions and discourses to build social, cultural and political settings based on the criteria of peace, equality, social justice and human rights. Specifically, this entails a contribution to the objectives set out in SDG 16, “Peace, Justice and Strong Institutions”, given that the proposed theoretical framework is grounded in Communication for Peace and Communication for Social Change, and includes a systematization of different strategies and experiences from a variety of social issuers, mainly institutions, non-governmental organizations (NGOs) or social movements, aimed at promoting peaceful and inclusive societies. Specifically, communication for peaceful social change and global citizenry contributes to the achievement of specific SDG 16 objectives, particularly 16.1: Significantly reduce all forms of violence... [...

Measurement of the Forward-Backward Asymmetry in the B -> K(*) mu+ mu- Decay and First Observation of the Bs -> phi mu+ mu- Decay

We reconstruct the rare decays $B^+ \to K^+\mu^+\mu^-$, $B^0 \to K^{*}(892)^0\mu^+\mu^-$, and $B^0_s \to \phi(1020)\mu^+\mu^-$ in a data sample corresponding to $4.4 {\rm fb^{-1}}$ collected in $p\bar{p}$ collisions at $\sqrt{s}=1.96 {\rm TeV}$ by the CDF II detector at the Fermilab Tevatron Collider. Using $121 \pm 16$ $B^+ \to K^+\mu^+\mu^-$ and $101 \pm 12$ $B^0 \to K^{*0}\mu^+\mu^-$ decays we report the branching ratios. In addition, we report the measurement of the differential branching ratio and the muon forward-backward asymmetry in the $B^+$ and $B^0$ decay modes, and the $K^{*0}$ longitudinal polarization in the $B^0$ decay mode with respect to the squared dimuon mass. These are consistent with the theoretical prediction from the standard model, and most recent determinations from other experiments and of comparable accuracy. We also report the first observation of the $B^0_s \to \phi\mu^+\mu^- decay and measure its branching ratio${\mathcal{B}}(B^0_s \to \phi\mu^+\mu^-) = [1.44 \pm 0.33 \pm 0.46] \times 10^{-6}$using$27 \pm 6$signal events. This is currently the most rare$B^0_s$ decay observed.Comment: 7 pages, 2 figures, 3 tables. Submitted to Phys. Rev. Let

Measurements of the properties of Lambda_c(2595), Lambda_c(2625), Sigma_c(2455), and Sigma_c(2520) baryons

We report measurements of the resonance properties of Lambda_c(2595)+ and Lambda_c(2625)+ baryons in their decays to Lambda_c+ pi+ pi- as well as Sigma_c(2455)++,0 and Sigma_c(2520)++,0 baryons in their decays to Lambda_c+ pi+/- final states. These measurements are performed using data corresponding to 5.2/fb of integrated luminosity from ppbar collisions at sqrt(s) = 1.96 TeV, collected with the CDF II detector at the Fermilab Tevatron. Exploiting the largest available charmed baryon sample, we measure masses and decay widths with uncertainties comparable to the world averages for Sigma_c states, and significantly smaller uncertainties than the world averages for excited Lambda_c+ states.Comment: added one reference and one table, changed order of figures, 17 pages, 15 figure

Search for a New Heavy Gauge Boson Wprime with Electron + missing ET Event Signature in ppbar collisions at sqrt(s)=1.96 TeV

We present a search for a new heavy charged vector boson $W^\prime$ decaying to an electron-neutrino pair in $p\bar{p}$ collisions at a center-of-mass energy of 1.96\unit{TeV}. The data were collected with the CDF II detector and correspond to an integrated luminosity of 5.3\unit{fb}^{-1}. No significant excess above the standard model expectation is observed and we set upper limits on $\sigma\cdot{\cal B}(W^\prime\to e\nu)$. Assuming standard model couplings to fermions and the neutrino from the $W^\prime$ boson decay to be light, we exclude a $W^\prime$ boson with mass less than 1.12\unit{TeV/}c^2 at the 95\unit{%} confidence level.Comment: 7 pages, 2 figures Submitted to PR

A Conserved Behavioral State Barrier Impedes Transitions between Anesthetic-Induced Unconsciousness and Wakefulness: Evidence for Neural Inertia

One major unanswered question in neuroscience is how the brain transitions between conscious and unconscious states. General anesthetics offer a controllable means to study these transitions. Induction of anesthesia is commonly attributed to drug-induced global modulation of neuronal function, while emergence from anesthesia has been thought to occur passively, paralleling elimination of the anesthetic from its sites in the central nervous system (CNS). If this were true, then CNS anesthetic concentrations on induction and emergence would be indistinguishable. By generating anesthetic dose-response data in both insects and mammals, we demonstrate that the forward and reverse paths through which anesthetic-induced unconsciousness arises and dissipates are not identical. Instead they exhibit hysteresis that is not fully explained by pharmacokinetics as previously thought. Single gene mutations that affect sleep-wake states are shown to collapse or widen anesthetic hysteresis without obvious confounding effects on volatile anesthetic uptake, distribution, or metabolism. We propose a fundamental and biologically conserved concept of neural inertia, a tendency of the CNS to resist behavioral state transitions between conscious and unconscious states. We demonstrate that such a barrier separates wakeful and anesthetized states for multiple anesthetics in both flies and mice, and argue that it contributes to the hysteresis observed when the brain transitions between conscious and unconscious states

Synchrotron radiation-based experimental determination of the optimal energy for cell radiotoxicity enhancement following photoelectric effect on stable iodinated compounds

This study was designed to experimentally evaluate the optimal X-ray energy for increasing the radiation energy absorbed in tumours loaded with iodinated compounds, using the photoelectric effect. SQ20B human cells were irradiated with synchrotron monochromatic beam tuned at 32.8, 33.5, 50 and 70 keV. Two cell treatments were compared to the control: cells suspended in 10 mg ml1 of iodine radiological contrast agent or cells pre-exposed with 10 mM of iodo-desoxyuridine (IUdR) for 48 h. Our radiobiological end point was clonogenic cell survival. Cells irradiated with both iodine compounds exhibited a radiation sensitisation enhancement. Moreover, it was energy dependent, with a maximum at 50 keV. At this energy, the sensitisation calculated at 10% survival was equal to 2.03 for cells suspended in iodinated contrast agent and 2.60 for IUdR. Cells pretreated with IUdR had higher sensitisation factors over the energy range than for those suspended in iodine contrast agent. Also, their survival curves presented no shoulder, suggesting complex lethal damages from Auger electrons. Our results confirm the existence of the 50 keV energy optimum for a binary therapeutic irradiation based on the presence of stable iodine in tumours and an external irradiation. Monochromatic synchrotron radiotherapy concept is hence proposed for increasing the differential effect between healthy and cancerous tissue irradiation