Search for pair and single production of new heavy quarks that decay to a ℤ boson and a third-generation quark in pp collisions at √ s=8 TeV with the ATLAS detector

A search is presented for the production of new heavy quarks that decay to a Z boson and a third-generation Standard Model quark. In the case of a new charge +2/3 quark (T), the decay targeted is T → Zt, while the decay targeted for a new charge −1/3 quark (B) is B → Zb. The search is performed with a dataset corresponding to 20.3 fb−1 of pp collisions at √ s = 8TeV recorded in 2012 with the ATLAS detector at the CERN Large Hadron Collider. Selected events contain a high transverse momentum Z boson candidate reconstructed from a pair of oppositely charged same-flavor leptons (electrons or muons), and are analyzed in two channels defined by the absence or presence of a third lepton. Hadronic jets, in particular those with properties consistent with the decay of a b-hadron, are also required to be present in selected events. Different requirements are made on the jet activity in the event in order to enhance the sensitivity to either heavy quark pair production mediated by the strong interaction, or single production mediated by the electroweak interaction. No significant excess of events above the Standard Model expectation is observed, and lower limits are derived on the mass of vector-like T and B quarks under various branching ratio hypotheses, as well as upper limits on the agnitude of electroweak coupling parameters.

Plant strengtheners enhance parasitoid attraction to herbivore-damaged cotton via qualitative and quantitative changes in induced volatiles

BACKGROUND Herbivore-damaged plants release a blend of volatile organic compounds (VOCs) that differs from undamaged plants. These induced changes are known to attract the natural enemies of the herbivores and therefore are expected to be important determinants of the effectiveness of biological control in agriculture. One way of boosting this phenomenon is the application of plant strengtheners, which has been shown to enhance parasitoid attraction in maize. It is unclear whether this is also the case for other important crops. RESULTS The plant strengtheners BTH [benzo (1,2,3) thiadiazole-7-carbothioic acid S-methyl ester] and laminarin were applied to cotton plants, and the effects on volatile releases and the attraction of three hymenopteran parasitoids, Cotesia marginiventris, Campoletis sonorensis and Microplitis rufiventris, were studied. After treated and untreated plants were induced by real or simulated caterpillar feeding, it was found that BTH treatment increased the attraction of the parasitoids, whereas laminarin had no significant effect. BTH treatment selectively increased the release of two homoterpenes and reduced the emission of indole, the latter of which had been shown to interfere with parasitoid attraction in earlier studies. Canonical variate analyses of the data show that the parasitoid responses were dependent on the quality rather than the quantity of volatile emission in this tritrophic interaction. CONCLUSION Overall, these results strengthen the emerging paradigm that induction of plant defences with chemical elicitors such as BTH could provide a sustainable and environmentally friendly strategy for biological control of pests by enhancing the attractiveness of cultivated plants to natural enemies of insect herbivores. © 2014 Society of Chemical Industry

Introduction to Soft-Collinear Effective Theory

Among resummation techniques for perturbative QCD in the context of collider and flavor physics, soft-collinear effective theory (SCET) has emerged as both a powerful and versatile tool, having been applied to a large variety of processes, from B-meson decays to jet production at the LHC. This book provides a concise, pedagogical introduction to this technique. It discusses the expansion of Feynman diagrams around the high-energy limit, followed by the explicit construction of the effective Lagrangian - first for a scalar theory, then for QCD. The underlying concepts are illustrated with the quark vector form factor at large momentum transfer, and the formalism is applied to compute soft-gluon resummation and to perform transverse-momentum resummation for the Drell-Yan process utilizing renormalization group evolution in SCET. Finally, the infrared structure of n-point gauge-theory amplitudes is analyzed by relating them to effective-theory operators. This text is suitable for graduate students and non-specialist researchers alike as it requires only basic knowledge of perturbative QCD.

Updated Next-to-Next-to-Leading-Order QCD Predictions for the Weak Radiative B -Meson Decays

Weak radiative decays of the B mesons belong to the most important flavor changing processes that provide constraints on physics at the TeV scale. In the derivation of such constraints, accurate standard model predictions for the inclusive branching ratios play a crucial role. In the current Letter we present an update of these predictions, incorporating all our results for the O(α2s) and lower-order perturbative corrections that have been calculated after 2006. New estimates of nonperturbative effects are taken into account, too. For the CP- and isospin-averaged branching ratios, we find Bsγ=(3.36±0.23)×10−4 and Bdγ=(1.73+0.12−0.22)×10−5, for Eγ>1.6  GeV. Both results remain in agreement with the current experimental averages. Normalizing their sum to the inclusive semileptonic branching ratio, we obtain Rγ≡(Bsγ+Bdγ)/Bcℓν=(3.31±0.22)×10−3. A new bound from Bsγ on the charged Higgs boson mass in the two-Higgs-doublet-model II reads MH±>480  GeV at 95% C.L.

Amygdala response to self-critical stimuli and symptom improvement in psychotherapy for depression

Background: Cognitive–behavioural therapy is efficacious in the treatment of major depressive disorder but response rates are still far from satisfactory. Aims: To better understand brain responses to individualised emotional stimuli and their association with outcome, to enhance treatment. Method: Functional magnetic resonance imaging data were collected prior to individual psychotherapy. Differences in brain activity during passive viewing of individualised self-critical material in 23 unmedicated out-patients with depression and 28 healthy controls were assessed. The associations between brain activity, cognitive and emotional change, and outcome were analysed in 21 patients. Results: Patients showed enhanced activity in the amygdala and ventral striatum compared with the control group. Non-response to therapy was associated with enhanced activity in the right amygdala compared with those who responded, and activity in this region was negatively associated with outcome. Emotional but not cognitive changes mediated this association. Conclusions: Amygdala hyperactivity may lessen symptom improvement in psychotherapy for depression through attenuating emotional skill acquisition.

Repair of Annulus fibrosus with Genipin-enhanced Fibrin Hydrogel and silk membrane- fleece

Introduction Low back pain is often caused by a trauma causing disc herniation and /or disc degeneration. Although there are some promising approaches for nucleus pulposus repair, the inner tissue of the intervertebral disc (IVD) so far no treatment or repair is available for annulus fibrosus (AF) injuries. Here we aimed to develop a new method to seal and repair AF injuries by using a silk fleece composite and a genipin enhanced hydrogel. Methods Bovine (b) IVDs were harvested under aseptic conditions and kept in free swelling conditions for 24h in high-glucose DMEM containing 5% bovine serum for equilibration (1). A circular 2mm biopsy punch (Polymed Medical Center, Switzerland) was used to form a reproducible defect in the AF. For filling the defect and keeping the silk composite in place a human-derived fibrin gel (Baxter Tisseel, Switzerland) enhanced with 4.2mg/ml of the cross linker genipin (Wako Chemicals GmbH, Germany) was used. The silk composite consists of a mesh- and a membrane side (Spintec Engineering GmbH, Germany); the membrane is facing outwards to form a seal. bIVDs were cultured in vitro for 14 days either under dynamic load in a custom-built bioreactor under physiological conditions (0.2MPa load and ±2° torsion at 0.2Hz for 8h/day) or static diurnal load of 0.2MPa (2). At the end of culture discs were checked for seal failure, disc height, metabolic activity, cell death by necrosis (LDH assay), DNA content and glycosaminoglycan content. Results Silk composite maintained its position throughout the 14 days of culture under loaded conditions. Although repaired discs performed slightly lower in cell activity, DNA and GAG content were in the range of the control. Also LDH resulted in similar values compared to control discs (Fig 1). Height loss in repaired discs was in the same range as for static diurnal loaded control samples. For dynamically loaded samples the decrease was comparable to the injured, unrepaired discs. Fig 1 LDH of repaired discs compared to control disc after 24h in free swelling conditions for equilibration and first three loading cycles. Conclusions Silk-genipin-fibrin reinforced hydrogel is a promising approach to close AF defects as tested by two degree of freedom loading. In further experiments cytocompatibility of genipin has to be investigated. References 1. Chan SC, Gantenbein-Ritter B. Preparation of intact bovine tail intervertebral discs for organ culture. J Vis Exp 2012, Feb 2;60(60):e3490. 2. Walser J, Ferguson SJ, Gantenbein-Ritter B. Design of a mechanical loading device to culture intact bovine caudal motional segments of the spine under twisting motion. In: Davies J, editors. Replacing animal models: a practical guide to creating and using biomimetic alternatives. Chichester, UK: John Wiley & Sons, Ltd.; 2012. p. 89-105. Acknowledgements This project is funded by the Gerbert Rüf Stiftung project # GRS-028/13 and the Swiss National Science Project SNF #310030_153411.

The nature of syntactic impairment in autism

This paper presents a first exploration of the syntactic abilities of autistic children using the framework of truncation theory (Rizzi 1993-4, 2000). It is the first step of an ongoing research project aiming to (a) provide a complete map of syntax in autism, for such work has never been attempted from a sound linguistic perspective (b) develop a targeted remediation program to enhance syntactic abilities of autistic children. Recently, a growing body of work has emphasized the existence of a causal relation between the acquisition of complex syntax (embedding) and the development of a theory of mind (in normally-developing, deaf and autistic children). Early identification and remediation of syntactic deficits is therefore crucial not only to enhance cognitive abilites related to theory of mind, but also because of the critical period hypothesis for language acquisition.

Genetically engineered silk and genipin-enhanced fibrin hydrogel for annulus fibrosus repair

INTRODUCTION: Around 80% of people are affected by low back pain at least once in their life, often caused by trauma provoking intervertebral disc (IVD) herniation and/or IVD degeneration. Apart from some promising approaches for nucleus pulposus repair, so far no treatment or repair is available for the outer fibrous tissue, annulus fibrosus (AF). We aimed for sealing and repairing an AF injury in a bovine IVD organ culture model in vitro over 14 days under different loading conditions. For this purpose, a silk fleece composite from Bombyx mori silk was combined with genipin-enhanced fibrin hydrogel [1]. METHODS: Bovine IVDs of 12-17 months old animals were isolated by first removing all surrounding tissue, followed by cutting out the IVDs [2]. Culturing of discs occurred in high glucose Dulbecco's Modified Eagle Medium (HG-DMEM) supplemented with 5% serum as previously described. On the next day, injury was induced using a 2mm biopsy punch (Polymed, Switzerland). The formed cavity was filled with (0.4%) genipin-enhanced human based fibrin hydrogel (35- 55mg/mL human fibrinogen, Baxter, Austria) and sealed with a silk fleece-membrane composite (Spintec Engineering, Germany). Different culture conditions were applied: free swelling, static diurnal load of 0.2MPa for 8h/d and complex loading at 0.2MPa compression combined with ± 2° torsion at 0.2Hz for 8h/d. Complex loading was applied by a custom built 2 degree of freedom bioreactor [3]. After 14 days of culture cell activity was determined with resazurin assay. Additionally, glycosaminoglycan (dimethyl-methylene blue), DNA (Hoechst) and collagen content (hydroxy-proline) were determined. Finally, real-time qPCR of major IVD marker genes was performed. RESULTS: The silk seal closing the injury site could successfully withstand the forces of all three loading conditions with no misplacement over the two weeks’ culture. Nevertheless, disc height of the repaired discs did not significantly differ from the injured group. The disc phenotype could be maintained as demonstrated by biochemical analysis of gene expression, cell activity, DNA-, collagen- and GAG content. The silk itself was evaluated to be highly biocompatible for hMSC, as revealed by cytotoxicity assays. DISCUSSION & CONCLUSIONS: The silk can be considered a highly-elastic and biocompatible material for AF closure and the genipin-enhanced fibrin hydrogel has also good biomechanical properties. However, the cyto-compatibility of genipin seems rather poor and other hydrogels and/or cross-linkers should be looked into. REFERENCES: 1 C.C. Guterl et al. (2014) Characterization of Mechanics and Cytocompatibility of Fibrin Genipin Annulus Fibrosus Sealant with the Addition of Cell Adhesion Molecules, Tissue Eng Part A 2 S.C. Chan, B. Gantenbein-Ritter (2012) Preparation of intact bovine tail intervertebral discs for organ culture, J Vis Exp 3 B Gantenbein et al. (2015) Organ Culture Bioreactors - Platforms to Study Human Intervertebral Disc Degeneration and Regenerative Therapy, Curr Stem Cell Res Ther [epub ahead of print] ACKNOWLEDGEMENTS: This project is supported by the Gebert Rüf Stiftung project # GRS-028/13.