A test of first order scaling in Nf=2 QCD

We complete our analysis of Nf=2 QCD based on the lattice staggered fermion formulation. Using a series of Monte Carlo simulations at fixed (amq*Ls^yh) one is able to test the universality class with given critical exponent yh. This strategy has been used to test the O(4) universality class and it has been presented at the previous Lattice conferences. No agreement was found with simulations in the mass range amq=[0.01335,0.15] using lattices with Ls=16 up to 32 and Lt=4. With the same strategy, we now investigate the possibility of a first order transition using a new set of Monte Carlo data corresponding to yh=3 in the same mass and volume range as the one used for O(4). A substantial agreement is observed both in the specific heat scaling and in the scaling of the chiral condensate, while the chiral susceptibilities still presents visible deviation from scaling in the mass range explored.Comment: 5 pages, 6 figures, Presented at the XXV International Symposium on Lattice Field Theory, July 30 - August 4 2007, Regensburg, German

Exchange coupling between silicon donors: the crucial role of the central cell and mass anisotropy

Donors in silicon are now demonstrated as one of the leading candidates for implementing qubits and quantum information processing. Single qubit operations, measurements and long coherence times are firmly established, but progress on controlling two qubit interactions has been slower. One reason for this is that the inter donor exchange coupling has been predicted to oscillate with separation, making it hard to estimate in device designs. We present a multivalley effective mass theory of a donor pair in silicon, including both a central cell potential and the effective mass anisotropy intrinsic in the Si conduction band. We are able to accurately describe the single donor properties of valley-orbit coupling and the spatial extent of donor wave functions, highlighting the importance of fitting measured values of hyperfine coupling and the orbital energy of the $1s$ levels. Ours is a simple framework that can be applied flexibly to a range of experimental scenarios, but it is nonetheless able to provide fast and reliable predictions. We use it to estimate the exchange coupling between two donor electrons and we find a smoothing of its expected oscillations, and predict a monotonic dependence on separation if two donors are spaced precisely along the [100] direction.Comment: Published version. Corrected b and B values from previous versio

A test of first order scaling in Nf =2 QCD: a progress report

We present the status of our analysis on the order of the finite temperature transition in QCD with two flavors of degenerate fermions. Our new simulations on large lattices support the hypothesis of the first order nature of the transition, showing a preliminary two state signal. We will discuss the implications and the next steps in our analysis.Comment: 6 pages, 4 figures. Talk presented at The XXVI International Symposium on Lattice Field Theory, July 14 - 19, 2008 - Williamsburg, Virginia, US

'You Treated Me Like an Object, I Don't Forgive You!': The Effect of Dehumanization on Interpersonal Forgiveness from the Victim's Perspective

Introduction. There is a gap in the literature on the impact of the perceptions of a victim of an offense upon their forgiveness towards the offender, particularly when those perceptions include dehumanization. Objectives. The present cross-sectional exploratory study aimed at examining whether the perceptions of being treated in a dehumanized fashion influences interpersonal forgiveness, avoidance, and revenge intentions of dehumanized victims towards the offender. Method. We recruited 149 individuals from the general population, who took part in an online task, consisting of remembering an offense they had been victim of and of a set of self-reported measures of dehumanization (uniqueness and nature), interpersonal forgiveness, avoidance, and revenge intentions. We used multiple linear regression to test the study’s hypotheses. Results. The perceived denial of the victims’ human uniqueness was not associated with the dependent variables, whereas the perceived denial of the victims’ human nature was significantly and negatively associated with interpersonal forgiveness and positively with avoidance and revenge intentions, after controlling for the effects of a set of known covariates. Conclusions. The results revealed a role for dehumanization (nature) in predicting the victims’ interpersonal forgiveness, avoidance, and revenge intentions. Implications for further research are discussed

Surface code architecture for donors and dots in silicon with imprecise and nonuniform qubit couplings

A scaled quantum computer with donor spins in silicon would benefit from a viable semiconductor framework and a strong inherent decoupling of the qubits from the noisy environment. Coupling neighbouring spins via the natural exchange interaction according to current designs requires gate control structures with extremely small length scales. We present a silicon architecture where bismuth donors with long coherence times are coupled to electrons that can shuttle between adjacent quantum dots, thus relaxing the pitch requirements and allowing space between donors for classical control devices. An adiabatic SWAP operation within each donor/dot pair solves the scalability issues intrinsic to exchange-based two-qubit gates, as it does not rely on sub-nanometer precision in donor placement and is robust against noise in the control fields. We use this SWAP together with well established global microwave Rabi pulses and parallel electron shuttling to construct a surface code that needs minimal, feasible local control.Comment: Published version - more detailed discussions, robustness to dephasing pointed out additionall

Insurance Between Firms: The Role of Internal Labor Markets

We investigate how Internal Labor Markets (ILMs) allow organizations to accommodate shocks calling for costly labor adjustments. Using data on workers' mobility within French business groups, we find that adverse shocks affecting affiliated firms boost the proportion of workers redeployed to other group units rather than external firms. This effect is stronger when labor regulations are stricter and destination-firms are more efficient or enjoy better growth opportunities. Affiliated firms hit by positive shocks rely on the ILM for new hires, especially high-skilled workers. Overall, ILMs emerge as a co-insurance mechanism within organizations, providing job stability to employees as a by-product

Praziquantel: its use in control of schistosomiasis in sub-Saharan Africa and current research needs

Treatment with praziquantel (PZQ) has become virtually the sole basis of schistosomiasis control in sub-Saharan Africa and elsewhere, and the drug is reviewed here in the context of the increasing rate that it is being used for this purpose. Attention is drawn to our relative lack of knowledge about the mechanisms of action of PZQ at the molecular level, the need for more work to be done on schistosome isolates that have been collected recently from endemic areas rather than those maintained in laboratory conditions for long periods, and our reliance for experimental work mainly on Schistosoma mansoni, little work having been done on S. haematobium. There is no evidence that resistance to PZQ has been induced in African schistosomes as a result of its large-scale use on that continent to date, but there is also no assurance that PZQ and/or schistosomes are in any way unique and that resistant organisms will not be selected as a result of widespread drug usage. The failure of PZQ to produce complete cures in populations given a routine treatment should therefore solicit considerable concern. With few alternatives to PZQ currently available and/or on the horizon, methods to monitor drug-susceptibility in African schistosomes need to be devised and used to help ensure that this drug remains effective for as long a time as possibl

Radiosurgery for trigeminal neuralgia using a linear accelerator with BrainLab system: report on initial experience in Lausanne, Switzerland

BACKGROUND/AIMS: Radiosurgery is an effective treatment for trigeminal neuralgia (TN) with minimal complications. Most experience is based on gamma knife radiosurgery (GKRS) and to a lesser extent on linear accelerators. METHODS: We report our initial experience in 17 patients with TN treated by an adapted linear accelerator using the BrainLab system. The trigeminal root entry zone immediately adjacent to the pons (target volume: 0.01-0.09 cm3, mean: 0.02 cm3) was targeted by use of a multileaf collimator to deliver 40-45 Gy to the 80% isodose (dose max 50-56 Gy). Median follow-up was 12 months (range: 1-60). RESULTS: All patients reported some initial improvement in level of pain after treatment (mean time: 1 month). Initial pain responses were as follows: 6 patients (35%) had complete pain relief and required no medication, 6 (35%) had occasional pain but were off medication, and 5 (30%) experienced partial relief of pain but still required medication, usually in lower doses. Five patients (29%) who experienced initial pain relief had recurrences ranging from 4-13 months after procedure. There were no major or minor complications of radiosurgery except one case of mild facial itching. CONCLUSION: Stereotactic radiosurgery using a linear accelerator appears to be effective and can be a favourable alternative to other procedures, including GKRS. The procedure is very safe and side effects are rare and minor. However, a randomised trial with a longer follow-up comparing radiosurgery to other surgical procedures is needed to assess the long term effectiveness of this treatmen