Derivation of the probability distribution function for the local density of states of a disordered quantum wire via the replica trick and supersymmetry

We consider the statistical properties of the local density of states of a one-dimensional Dirac equation in the presence of various types of disorder with Gaussian white-noise distribution. It is shown how either the replica trick or supersymmetry can be used to calculate exactly all the moments of the local density of states.' Careful attention is paid to how the results change if the local density of states is averaged over atomic length scales. For both the replica trick and supersymmetry the problem is reduced to finding the ground state of a zero-dimensional Hamiltonian which is written solely in terms of a pair of coupled spins which are elements of u(1, 1). This ground state is explicitly found for the particular case of the Dirac equation corresponding to an infinite metallic quantum wire with a single conduction channel. The calculated moments of the local density of states agree with those found previously by Al'tshuler and Prigodin [Sov. Phys. JETP 68 (1989) 198] using a technique based on recursion relations for Feynman diagrams. (C) 2001 Elsevier Science B.V. All rights reserved.

The spectrum of D-slash in QCD via replicas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Approccio meccanico statistico allo studio delle Macchine di Boltzmann Ristrette

La Macchina di Boltzmann Ristretta (RBM) è una rete neurale a due strati utilizzata principalmente nell'apprendimento non supervisionato. La sua capacità nel rappresentare complesse relazioni insite nei dati attraverso distribuzioni di tipo Boltzmann Gibbs la rende un oggetto particolarmente interessante per un approfondimento teoretico in ambito fisico matematico. In questa tesi vengono presentati due ambiti di applicazione della meccanica statistica all'apprendimento automatico. 1) La similarità della RBM a unità binarie con il modello di Ising permette di sfruttare un'espansione alle alte temperature per approssimare l'energia libera, termine presente nel gradiente della likelihoood e difficile da trattare numericamente. I risultati ottenuti con questa tecnica sul dataset MNIST sono paragonabili a quelli ottenuti dalla Contrastive Divergence, che utilizza invece metodi di Monte Carlo. 2) L'equivalenza statistica della variante ibrida di RBM con il modello di Hopfield permette di studiare la taglia del training set necessaria per l'apprendimento attraverso l'analisi del problema inverso, in cui i ruoli di spin e pattern sono invertiti. Viene quindi presentato un metodo basato sulla teoria di Gauge che permette di derivare il diagramma di fase del modello di Hopfield duale sulla linea di Nishimori in funzione della temperatura e del rapporto tra numero di campioni e dimensione del sistema.

Some new killing trick: Welfare reform and drug markets in a U.S. urban ghetto

Ethnographic data collected over a 5-year period is analyzed to determine how the Personal Responsibility & Work Opportunity Reconciliation Act of 1996 (PRWORA) has affected the lives of young male drug dealers from AIDS-afflicted families residing in Detroit. The data analysis indicated that the participants perceived drug dealing as the only viable employment opportunity for meeting the quotidian & health care needs of their families. The findings also revealed that the participants were highly aware of local political processes & the necessities of caring for relatives living with AIDS. Additional attention is dedicated to exploring the state of MI's rationale for ending the General Assistance Program, the sociocultural foundations of the PRWORA, various stipulations of the PRWORA, & how the PRWORA has augmented the legal vulnerability of welfare recipients. It is concluded that the PRWORA will force many welfare recipients to engage in illicit activities & will generally decrease recipients' health. 59 References. J. W. Parker

Replica management in real-time Ada 95 applications

In this paper, we present some of the fault tolerance management mechanisms being implemented in the Multi-μ architecture, namely its support for replica non-determinism. In this architecture, fault tolerance is achieved by node active replication, with software based replica management and fault tolerance transparent algorithms. A software layer implemented between the application and the real-time kernel, the Fault Tolerance Manager (FTManager), is the responsible for the transparent incorporation of the fault tolerance mechanisms The active replication model can be implemented either imposing replica determinism or keeping replica consistency at critical points, by means of interactive agreement mechanisms. One of the Multi-μ architecture goals is to identify such critical points, relieving the underlying system from performing the interactive agreement in every Ada dispatching point.

Plasmacytoid dendritic cells: one-trick ponies or workhorses of the immune system?

Plasmacytoid dendritic cells (pDCs) were first described as interferon-producing cells and, for many years, their overlapping characteristics with both lymphocytes and classical dendritic cells (cDCs) created confusion over their exact ontogeny. In this Viewpoint article, Nature Reviews Immunology asks five leaders in the field to discuss their thoughts on the development and functions of pDCs--do these cells serve mainly as a major source of type I interferons or do they also make other important contributions to immune responses?

General method to determine replica symmetry breaking transitions

We introduce a new parameter to investigate replica symmetry breaking transitions using finite-size scaling methods. Based on exact equalities initially derived by F. Guerra this parameter is a direct check of the self-averaging character of the spin-glass order parameter. This new parameter can be used to study models with time reversal symmetry but its greatest interest lies in models where this symmetry is absent. We apply the method to long-range and short-range Ising spin-glasses with and without a magnetic field as well as short-range multispin interaction spin-glasses.

Therapeutic drug monitoring in cancer - Are we missing a trick?

Therapeutic drug monitoring (TDM) can be defined as the measurement of drug in biological samples to individualise treatment by adapting drug dose to improve efficacy and/or reduce toxicity. The cytotoxic drugs are characterised by steep dose-response relationships and narrow therapeutic windows. Inter-individual pharmacokinetic (PK) variability is often substantial. There are, however, a multitude of reasons why TDM has never been fully implemented in daily oncology practice. These include difficulties in establishing appropriate concentration target, common use of combination chemotherapies and the paucity of published data from pharmacological trials. The situation is different with targeted therapies. The large interindividual PK variability is influenced by the pharmacogenetic background of the patient (e.g. cytochrome P450 and ABC transporters polymorphisms), patient characteristics such as adherence to treatment and environmental factors (drug-drug interactions). Retrospective studies have shown that targeted drug exposure correlates with treatment response in various cancers. Evidence for imatinib currently exists, others are emerging for compounds including nilotinib, dasatinib, erlotinib, sunitinib, sorafenib and mammalian target of rapamycin (mTOR) inhibitors. Applications for TDM during oral targeted therapies may best be reserved for particular situations including lack of therapeutic response, severe or unexpected toxicities, anticipated drug-drug interactions and concerns over adherence treatment. There are still few data with monoclonal antibodies (mAbs) in favour of TDM approaches, even if data showed encouraging results with rituximab and cetuximab. TDM of mAbs is not yet supported by scientific evidence. Considerable effort should be made for targeted therapies to better define concentration-effect relationships and to perform comparative randomised trials of classic dosing versus pharmacokinetically-guided adaptive dosing.

In vivo assessment of use-dependent brain plasticity--beyond the "one trick pony" imaging strategy.

This article has been written as a comment to Dr Thomas and Dr Baker's article "Teaching an adult brain new tricks: A critical review of evidence for training-dependent structural plasticity in humans". We deliberately expand on the key question about the biological substrates underlying use-dependent brain plasticity rather than reiterating the authors' main points of criticism already addressed in more general way by previous publications in the field. The focus here is on the following main issues: i) controversial brain plasticity findings in voxel-based morphometry studies are partially due to the strong dependency of the widely used T1-weighted imaging protocol on varying magnetic resonance contrast contributions; ii) novel concepts in statistical analysis allow one to directly infer topological specificity of structural brain changes associated with plasticity. We conclude that iii) voxel-based quantification of relaxometry derived parameter maps could provide a new perspective on use-dependent plasticity by characterisation of brain tissue property changes beyond the estimation of volume and cortical thickness changes. In the relevant sections we respond to the concerns raised by Dr Thomas and Dr Baker from the perspective of the proposed data acquisition and analysis strategy.

The Invisible Institutional Repository: Missing a Trick (and Missing Fulltext)?

Presentation at Open Repositories 2014, Helsinki, Finland, June 9-13, 2014

"They're trying to trick us!": Making sense of anti-oppressive children's literature in the elementary school classroom

This study examines how children make sense of “anti-oppressive” children’s literature in the classroom, specifically, books that integrate and promote positive portrayals of gender non-conformity and sexual diversity. Through a feminist poststructural lens, I conducted ethnographic observations and reading groups with twenty students in a grade one/two classroom to explore how children engage with these storybooks. I further explored how the use of these books in the classroom might help to mediate and negotiate existing gendered and heteronormative beliefs and practices within educational settings. The books used in this study challenge oppressive gender and sexuality regimes within mainstream children’s literature that have traditionally served to marginalize and silence gender non-conforming and LGBTQ individuals. Responses from participants in this study aid in questioning how dominant discourses of gender and sexuality are produced and reinforced, as well as where we may find opportunities for change and reform within the elementary school classroom.