Improved diffusion Monte Carlo propagators for bosonic systems using Ito calculus

The construction of importance sampled diffusion Monte Carlo (DMC) schemes accurate to second order in the time step is discussed. A central aspect in obtaining efficient second order schemes is the numerical solution of the stochastic differential equation (SDE) associated with the Fokker-Plank equation responsible for the importance sampling procedure. In this work, stochastic predictor-corrector schemes solving the SDE and consistent with It\uf4 calculus are used in DMC simulations of helium clusters. These schemes are numerically compared with alternative algorithms obtained by splitting the Fokker-Plank operator, an approach that we analyze using the analytical tools provided by It\uf4 calculus. The numerical results show that predictor-corrector methods are indeed accurate to second order in the time step and that they present a smaller time step bias and a better efficiency than second order split-operator derived schemes when computing ensemble averages for bosonic systems. The possible extension of the predictor-corrector methods to higher orders is also discussed

Large memcapacitance and memristance at Nb:SrTiO3_{3} / La0.5_{0.5}Sr0.5_{0.5}Mn0.5_{0.5}Co0.5_{0.5}O3−δ_{3-\delta} Topotactic Redox Interface

The possibility to develop neuromorphic computing devices able to mimic the extraordinary data processing capabilities of biological systems spurs the research on memristive systems. Memristors with additional functionalities such as robust memcapacitance can outperform standard devices in key aspects such as power consumption or miniaturization possibilities. In this work, we demonstrate a large memcapacitive response of a perovskite memristive interface, using the topotactic redox ability of La$_{0.5}$Sr$_{0.5}$Mn$_{0.5}$Co$_{0.5}$O$_{3-\delta}$ (LSMCO, 0 $\leq$ $\delta$ $\leq$ 0.62). We demonstrate that the multi-mem behaviour originates at the switchable n-p diode formed at the Nb:SrTiO3/LSMCO interface. We found for our Nb:SrTiO$_{3}$/LSMCO/Pt devices a memcapacitive effect C$_{HIGH}$/C$_{LOW}$ ~ 100 at 150 kHz. The proof-of-concept interface reported here opens a promising venue to use topotactic redox materials for disruptive nanoelectronics, with straightforward applications in neuromorphic computing technology.Comment: 14 pages, 5 figures, to appear in Appl. Phys. Let

Efficiency in Multi-objective Games

In a multi-objective game, each agent individually evaluates each overall action-profile on multiple objectives. I generalize the price of anarchy to multi-objective games and provide a polynomial-time algorithm to assess it. This work asserts that policies on tobacco promote a higher economic efficiency

An American Philosophy of Punishment: Moral Permissibility, the Inferiorities of Punishment, and a Case for Pure Restitution

“An American Philosophy of Punishment: Moral Permissibility, the Inferiorities of Punishment, and a Case for Pure Restitution” is an examination of the paradigm of criminal punishment currently implemented in the United States and the inherent flaws of ‘punishment’ as a system of justice. The characteristics of punishment are evaluated from a perspective, “punishment by necessity,” which attempts to justify criminal punishment for a lack of viable alternatives. David Boonin, in his book, The Problem of Punishment, offers a robust alternative paradigm of criminal justice- ‘pure restitution’. Boonin advances two arguments: (1) ‘pure restitution’ is capable of replacing punishment as a paradigm of criminal justice and (2) restitution should replace punishment because punishment is morally impermissible. This paper considers two of the most notorious objections to Barnett’s pure restitution, the “irreparable harms” and “third party victims” objections, as well as the moral status of punishment. The “irreparable harms” objection claims that the inability of restitution to entirely repair victims in crimes against the person indicates that restitution cannot offer any remedy, and that this inability is unacceptable. This objection fails to recognize the possibility for partial reparations, nor that punishment is equally incapable of wholly repairing the victims of these crimes. The “third party victims” objection claims that by compelling the offender to make restitution to the victim, the state is harming individuals in proximity to the offender, but the state is prohibited from harming individuals. This objection fails to consider the critical distinction of intent and culpability; the state does not intend to harm third parties by exacting restitution, but does so as a foreseeable consequence, whereas the offender caused an intentional harm, and thus carries a higher degree of blameworthiness. Additionally, the present implementation of restitution is considered by considering the relevant legal precedent, the Constitutional situation of restitution, and a hypothetical implementation scenario, which highlights the potential for “crime insurance/ tax”, and the other practical implications of implementing restitution

Clinical Features of 705 Borrelia burgdorferi Seropositive Patients in an Endemic Area of Northern Italy

Background. Lyme Borreliosis is a multisystemic infection caused by spirochetes of Borrelia burgdorferi sensu lato complex. The features of Lyme Borreliosis may differ in the various geographical areas, primarily between the manifestations found in America and those found in Europe and Asia. Objective. to describe the clinical features of Lyme Borreliosis in an endemic geographic area such as Friuli-Venezia Giulia in the Northeastern part of Italy. Methods.The medical records of patients resulted seropositive for Borrelia burgdorferi have been retrospectively recorded and analyzed. Results. Seven hundred and five patients met the inclusion criteria, 363 males and 342 females. Erythema migrans was the most common manifestation, detected in 437 patients. Other classical cutaneous manifestations included 58 cases of multiple erythema migrans, 7 lymphadenosis benigna cutis, and 18 acrodermatitis chronica atrophicans. The musculoskeletal system was involved in 511 patients. Four hundred and sixty patients presented a neurological involvement. Flu-like symptoms preceded or accompanied or were the only clinical feature in 119 patients. Comments.The manifestations of Lyme borreliosis recorded in this study are similar to the ones of other endemic areas in Europe, even if there are some peculiar features which are different from those reported in Northern Europe and in the USA

Investigating Phosphopantothenoylcysteine Synthetase as a Potential Antibacterial Target.

Phosphopantothenoylcysteine synthetase (PPCS) is the second enzyme in the universal Coenzyme A (CoA) biosynthetic pathway. PPCS is responsible for catalyzing the condensation of 4’-phosphopantothenate (PPA) and L-cysteine via nucleotide triphosphate activation of PPA. PPCSs have been broadly classified into three types (Type I-III) based upon expression profile and nucleotide triphosphate specificity. Type I PPCSs are found in a majority of bacteria and archaea, utilize CTP for activation of PPA in the first half reaction, and are expressed as the C-terminal domain of a fusion protein with phosphopantothenoylcysteine decarboxylase (PPCDC). Type II PPCSs are in eukaryotes, utilize both CTP and ATP, and expressed separately from PPCDC as a monofunctional enzyme. Type III PPCSs are found in certain bacteria, utilize CTP, and are expressed as a monofunctional enzyme. Based upon the difference in nucleotide triphosphate specificity and PPCS type between human and bacteria, PPCS was chosen for exploration as a possible novel antibacterial target. Four mimics of the activated intermediate produced from the first half reaction catalyzed by PPCS were synthesized in twelve steps in average of 18% overall yield. These four intermediate mimics were tested in vitro for PPCS inhibition against PPCS from E. coli, E. faecalis, S. pneumoniae, and human. IC50s were obtained for all four intermediate mimics and the best mimic had a Ki of 24 nM against efPPCS. The best intermediate mimic displayed low nanomolar potency versus the bacterial forms of PPCS while displaying 100-1000 fold selectivity for the bacterial PPCS over human PPCS. Further, three of the intermediate mimics were used in a structural study to elucidate how they bind within the PPCS active site. The co-crystal structures of PPCS and the three intermediate mimics were solved to 2.11-2.37 Å. Analogs of PPA where the carboxylate was replaced with either an amine or thiol. The phosphorylated thiol PPA mimic was found to act as a competitive inhibitor of PPCS with respect to PPA with a Ki of 12 M. This study shows that it is possible to selectively inhibit bacterial PPCS over human PPCS and thus PPCS represents an antibacterial target worthy of further investigation.Ph.D.Medicinal ChemistryUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/78970/1/jamesdo_1.pd

Collective Awareness for Abnormality Detection in Connected Autonomous Vehicles

The advancements in connected and autonomous vehicles in these times demand the availability of tools providing the agents with the capability to be aware and predict their own states and context dynamics. This article presents a novel approach to develop an initial level of collective awareness (CA) in a network of intelligent agents. A specific collective self-awareness functionality is considered, namely, agent-centered detection of abnormal situations present in the environment around any agent in the network. Moreover, the agent should be capable of analyzing how such abnormalities can influence the future actions of each agent . Data-driven dynamic Bayesian network (DBN) models learned from time series of sensory data recorded during the realization of tasks (agent network experiences) are here used for abnormality detection and prediction. A set of DBNs, each related to an agent , is used to allow the agents in the network to reach synchronously aware possible abnormalities occurring when available models are used on a new instance of the task for which DBNs have been learned. A growing neural gas (GNG) algorithm is used to learn the node variables and conditional probabilities linking nodes in the DBN models; a Markov jump particle filter (MJPF) is employed for state estimation and abnormality detection in each agent using learned DBNs as filter parameters. Performance metrics are discussed to asses the algorithm’s reliability and accuracy. The impact is also evaluated by the communication channel used by the network to share the data sensed in a distributed way by each agent of the network. The IEEE 802.11p protocol standard has been considered for communication among agents. Performances of the DBN-based abnormality detection models under different channel and source conditions are discussed. The effects of distances among agents and of the delays and packet losses are analyzed in different scenario categories (urban, suburban, and rural). Real data se..