Phenomenology of The Left-Right Twin Higgs Model

The twin Higgs mechanism has recently been proposed to solve the little hierarchy problem. We study the implementation of the twin Higgs mechanism in left-right models. At TeV scale, heavy quark and gauge bosons appear, with rich collider phenomenology. In addition, there are extra Higgses, some of which couple to both the Standard Model fermion sector and the gauge sector, while others couple to the gauge bosons only. We present the particle spectrum, and study the general features of the collider phenomenology of this class of model at the Large Hadron Collider.Comment: 41 pages, version appears in PR

Mafic alkaline metasomatism in the lithosphere underneath East Serbia: evidence from the study of xenoliths and the host alkali basalts

Effects of mafic alkaline metasomatism have been investigated by a combined study of the East Serbian mantle xenoliths and their host alkaline rocks. Fertile xenoliths and tiny mineral assemblages found in depleted xenoliths have been investigated. Fertile lithologies are represented by clinopyroxene (cpx)-rich lherzolite and spinel (sp)-rich olivine websterite containing Ti–Al-rich Cr-augite, Fe-rich olivine, Fe–Al-rich orthopyroxene and Al-rich spinel. Depleted xenoliths, which are the predominant lithology in the suite of East Serbian xenoliths, are harzburgite, cpx-poor lherzolite and rare Mg-rich dunite. They contain small-scale assemblages occurring as pocket-like, symplectitic or irregular, deformation-assisted accumulations of metasomatic phases, generally composed of Ti–Al- and incompatible element-rich Cr-diopside, Cr–Fe–Ti-rich spinel, altered glass, olivine, apatite, ilmenite, carbonate, feldspar, and a high-TiO2 (c. 11 wt%) phlogopite. The fertile xenoliths are too rich in Al, Ca and Fe to simply represent undepleted mantle. By contrast, their composition can be reproduced by the addition of 5–20 wt% of a basanitic melt to refractory mantle. However, textural relationships found in tiny mineral assemblages inside depleted xenoliths imply the following reaction: opx+sp1 (primary mantle Cr-spinel) ±phlogopite+Si-poor alkaline melt=Ti–Al-cpx+sp2 (metasomatic Ti-rich spinel)±ol±other minor phases. Inversion modelling, performed on the least contaminated and most isotopically uniform host basanites (87Sr/86Sr=c. 0.7031; 143Nd/144Nd=c. 0.5129), implies a source that was enriched in highly and moderately incompatible elements (c. 35–40× chondrite for U–Th–Nb–Ta, 2× chondrite for heavy rare earth elements (HREE), made up of clinopyroxene, carbonate (c. 5%), and traces of ilmenite (c. 1%) and apatite (c. 0.05%). A schematic model involves: first, percolation of CO2- and H2O-rich fluids and precipitation of metasomatic hydrous minerals; and, second, the subsequent breakdown of these hydrous minerals due to the further uplift of hot asthenospheric mantle. This model links intraplate alkaline magmatism to lithospheric mantle sources enriched by sublithospheric melts at some time in the past

Income Disparity between Japan and ASEAN-5 Economies: Converge, Catching Up or Diverge?

The objective of this study is to empirically examine the income disparity between Japan and each of the five major economies of South East Asia (ASEAN-5) during the period of 1960 to 1997, utilizing the popular augmented Dickey-Fuller (ADF) unit root test. The results provide evidence of income divergence between Japan and each of the ASEAN-5 economies. To avoid the problem associated with structural break, this study proceeds with the jointly crash and changes in trend model proposed by Zivot and Andrews (1992), and is able to obtain evidence of long run income convergence between the Japanese and Singaporean economies. As for the rest of the four ASEAN countries- Indonesia, Malaysia, the Philippines and Thailand, the earlier results of income divergence remain valid and hence suggest that it would be a more realistic and urgent goal to narrow the income gap among these five core economies of ASEAN.

Too little and too much: investigating the role of balanced prefrontal neural activity in behavioural flexibility

A consistent deficit of schizophrenia, among numerous neuropsychiatric disorders, is impaired cognitive flexibility, the prefrontal-dependent ability to overcome pre-existing behavioural strategies to adjust behaviour in line with changing environmental demands. Prefrontal gamma-aminobutyric acid (GABA) dysfunction has been linked to these cognitive impairments and there is evidence that tasks requiring cognitive flexibility require the medial prefrontal cortex (mPFC) and local GABA-mediated transmission. In this thesis, I report five experiments in which an operant strategy shifting task was used to test whether both increased and decreased GABA inhibition in the mPFC impair strategy shifting in Lister Hooded rats. In experiment 1, prefrontal hypo-activation or functional disinhibition was induced by micro-infusing the GABAA agonist muscimol (62.5ng/side) or antagonist picrotoxin (PTX) (300ng/side) respectively, into the mPFC; these manipulations had markedly impaired sustained attention in a 5-choice serial reaction time (5CSRT) test during previous research. Results showed that neither prefrontal hypo-activation nor disinhibition affected shifting from a spatial response to a visual light-cue-based response, although disinhibition impaired expression of the spatial response and increased trial omissions. Remarkably, all rats required up to three times the number of trials to shift the responses as compared to previous studies in other rat strains. Two additional behavioural studies without infusions followed; experiment 2 showed removal of pre-training cue-light pre-exposure and reduction of training trials for the initial spatial response strategy did not facilitate shifting to cue-based strategy; experiment 3 showed rats could acquire the cue strategy and then shift to the spatial response strategy, and also perform spatial response reversals, within a similar number of trials as in previous studies. Ultimately, however, there was always a substantially higher shift cost for response-to-cue than for the cue-to-response shift (~ 200 trials). Experiment 4 investigated effects of mPFC disinhibition and hypo-activation on shifting from cue to response strategies, and there is evidence to suggest prefrontal picrotoxin disrupted shifting ability, impaired expression of rule retrieval following rule acquisition, and response latency. Additionally, experiment 5 found that administering the same prefrontal disinhibition, prior to initial rule acquisition, as well as prior to strategy shifting, increased perseveration. Finally, a Bayesian analysis approach was used to infer the types of learning strategies that rats were using during task performance, with preliminary results suggesting that rats predominantly use a lose-shift strategy during the first trials of shifting to a spatial response. From these data one conclusion is that when present during initial rule learning prefrontal disinhibition may augment reward-association, and impair expression of newly learnt shift rules, thus increasing perseveration

Periosteum: biology, regulation, and response to osteoporosis therapies

Periosteum contains osteogenic cells that regulate the outer shape of bone and work in coordination with inner cortical endosteum to regulate cortical thickness and the size and position of a bone in space. Induction of periosteal expansion, especially at sites such as the lumbar spine and femoral neck, reduces fracture risk by modifying bone dimensions to increase bone strength. The cell and molecular mechanisms that selectively and specifically activate periosteal expansion, as well as the mechanisms by which osteoporosis drugs regulate periosteum, remain poorly understood. We speculate that an alternate strategy to protect human bones from fracture may be through targeting of the periosteum, either using current or novel agents. In this review, we highlight current concepts of periosteal cell biology, including their apparent differences from endosteal osteogenic cells, discuss the limited data regarding how the periosteal surface is regulated by currently approved osteoporosis drugs, and suggest one potential means through which targeting periosteum may be achieved. Improving our understanding of mechanisms controlling periosteal expansion will likely provide insights necessary to enhance current and develop novel interventions to further reduce the risk of osteoporotic fractures

Practical implementation of an interior point nonmonotone line search filter method

Versão não definitiva do artigoHere we present a primal-dual interior point nonmonotone line search filter method for nonlinear programming. The filter relies on three measures, the feasibility, the centrality and the optimality presented in the optimality conditions, considers relaxed acceptability criteria for the step size and includes a feasibility restoration phase. The evaluation of the method is until now made on small problems and a comparison is provided with a merit function approach

Surface velocity and ice discharge of the ice cap on King George Island, Antarctica

Glaciers on King George Island, Antarctica, have shown retreat and surface lowering in recent decades, concurrent with increasing air temperatures. A large portion of the glacier perimeter is ocean-terminating, suggesting possible large mass losses due to calving and submarine melting. Here we estimate the ice discharge into the ocean for the King George Island ice cap. L-band synthetic aperture radar images covering the time-span January 2008 to January 2011 over King George Island are processed using an intensity-tracking algorithm to obtain surface velocity measurements. Pixel offsets from 40 pairs of radar images are analysed and inverted to estimate a weighted average surface velocity field. Ice thicknesses are derived from simple principles of ice flow mechanics using the computed surface velocity fields and in situ thickness data. The maximum ice surface speeds reach mayor que 225 m/yr, and the total ice discharge for the analysed flux gates of King George Island is estimated to be 0.720+/-0.428 Gt/yr, corresponding to a specific mass loss of 0.64+/-0.38 m w.e./yr over the area of the entire ice cap (1127 km2)

Integrating the promotion of physical activity within a smoking cessation programme: Findings from collaborative action research in UK Stop Smoking Services

Background: Within the framework of collaborative action research, the aim was to explore the feasibility of developing and embedding physical activity promotion as a smoking cessation aid within UK 6/7-week National Health Service (NHS) Stop Smoking Services. Methods: In Phase 1 three initial cycles of collaborative action research (observation, reflection, planning, implementation and re-evaluation), in an urban Stop Smoking Service, led to the development of an integrated intervention in which physical activity was promoted as a cessation aid, with the support of a theoretically based self-help guide, and self monitoring using pedometers. In Phase 2 advisors underwent training and offered the intervention, and changes in physical activity promoting behaviour and beliefs were monitored. Also, changes in clients’ stage of readiness to use physical activity as a cessation aid, physical activity beliefs and behaviour and physical activity levels were assessed, among those who attended the clinic at 4-week post-quit. Qualitative data were collected, in the form of clinic observation, informal interviews with advisors and field notes. Results: The integrated intervention emerged through cycles of collaboration as something quite different to previous practice. Based on field notes, there were many positive elements associated with the integrated intervention in Phase 2. Self-reported advisors’ physical activity promoting behaviour increased as a result of training and adapting to the intervention. There was a significant advancement in clients’ stage of readiness to use physical activity as a smoking cessation aid. Conclusions: Collaboration with advisors was key in ensuring that a feasible intervention was developed as an aid to smoking cessation. There is scope to further develop tailored support to increasing physical activity and smoking cessation, mediated through changes in perceptions about the benefits of, and confidence to do physical activity

Ubiquitination and proteasomal degradation of ATG12 regulates its proapoptotic activity

During macroautophagy, conjugation of ATG12 to ATG5 is essential for LC3 lipidation and autophagosome formation. Additionally, ATG12 has ATG5-independent functions in diverse processes including mitochondrial fusion and mitochondrial-dependent apoptosis. In this study, we investigated the regulation of free ATG12. In stark contrast to the stable ATG12–ATG5 conjugate, we find that free ATG12 is highly unstable and rapidly degraded in a proteasome-dependent manner. Surprisingly, ATG12, itself a ubiquitin-like protein, is directly ubiquitinated and this promotes its proteasomal degradation. As a functional consequence of its turnover, accumulation of free ATG12 contributes to proteasome inhibitor-mediated apoptosis, a finding that may be clinically important given the use of proteasome inhibitors as anticancer agents. Collectively, our results reveal a novel interconnection between autophagy, proteasome activity, and cell death mediated by the ubiquitin-like properties of ATG12