Comment on ``Cosmological Gamma Ray Bursts and the Highest Energy Cosmic Rays''

In a letter with the above title, published some time ago in PRL, Waxman made the interesting suggestion that cosmological gamma ray bursts (GRBs) are the source of the ultra high energy cosmic rays (UHECR). This has also been proposed independently by Milgrom and Usov and by Vietri. However, recent observations of GRBs and their afterglows and in particular recent data from the Akeno Great Air Shwoer Array (AGASA) on UHECR rule out extragalactic GRBs as the source of UHECR.Comment: Comment on a letter with the above title published by E. Waxman in PRL 75, 386 (1995). Submitted for publication in PRL/Comment

Computer-aided Melody Note Transcription Using the Tony Software: Accuracy and Efficiency

accepteddate-added: 2015-05-24 19:18:46 +0000 date-modified: 2017-12-28 10:36:36 +0000 keywords: Tony, melody, note, transcription, open source software bdsk-url-1: https://code.soundsoftware.ac.uk/attachments/download/1423/tony-paper_preprint.pdfdate-added: 2015-05-24 19:18:46 +0000 date-modified: 2017-12-28 10:36:36 +0000 keywords: Tony, melody, note, transcription, open source software bdsk-url-1: https://code.soundsoftware.ac.uk/attachments/download/1423/tony-paper_preprint.pdfWe present Tony, a software tool for the interactive an- notation of melodies from monophonic audio recordings, and evaluate its usability and the accuracy of its note extraction method. The scientific study of acoustic performances of melodies, whether sung or played, requires the accurate transcription of notes and pitches. To achieve the desired transcription accuracy for a particular application, researchers manually correct results obtained by automatic methods. Tony is an interactive tool directly aimed at making this correction task efficient. It provides (a) state-of-the art algorithms for pitch and note estimation, (b) visual and auditory feedback for easy error-spotting, (c) an intelligent graphical user interface through which the user can rapidly correct estimation errors, (d) extensive export functions enabling further processing in other applications. We show that Tony’s built in automatic note transcription method compares favourably with existing tools. We report how long it takes to annotate recordings on a set of 96 solo vocal recordings and study the effect of piece, the number of edits made and the annotator’s increasing mastery of the software. Tony is Open Source software, with source code and compiled binaries for Windows, Mac OS X and Linux available from https://code.soundsoftware.ac.uk/projects/tony/

Berry's phase contribution to the anomalous Hall effect of gadolinium

When conduction electrons are forced to follow the local spin texture, the resulting Berry phase can induce an anomalous Hall effect (AHE). In gadolinium, as in double-exchange magnets, the exchange interaction is mediated by the conduction electrons and the AHE may therefore resemble that of chromium dioxide and other metallic double-exchange ferromagnets. The Hall resistivity, magnetoresistance, and magnetization of single crystal gadolinium were measured in fields up to 30 T. Measurements between 2 K and 400 K are consistent with previously reported data. A scaling analysis for the Hall resistivity as a function of the magnetization suggests the presence of a Berry's-phase contribution to the anomalous Hall effect.Comment: 6 pages, 7 figures, submitted to Phys. Rev.

Doping of inorganic materials in microreactors – preparation of Zn doped Fe₃O₄ nanoparticles

Microreactor systems are now used more and more for the continuous production of metal nanoparticles and metal oxide nanoparticles owing to the controllability of the particle size, an important property in many applications. Here, for the first time, we used microreactors to prepare metal oxide nanoparticles with controlled and varying metal stoichiometry. We prepared and characterised Zn-substituted Fe₃O₄ nanoparticles with linear increase of Zn content (ZnxFe₃−xO₄ with 0 ≤ x ≤ 0.48), which causes linear increases in properties such as the saturation magnetization, relative to pure Fe₃O₄. The methodology is simple and low cost and has great potential to be adapted to the targeted doping of a vast array of other inorganic materials, allowing greater control on the chemical stoichiometry for nanoparticles prepared in microreactors

HIV infection and psychiatric illness

Objective: To review the clinical features and current knowledge on the treatment of psychiatric symptoms and disorders in patients with human immunodeficiency virus (HIV) infection. Method: We searched the PubMed database combining HIV/AIDS with different keywords for psychiatric diagnoses and symptoms (e.g. depression, mania, anxiety, psychosis, dementia, substance abuse) and for psychopharmacological treatment. The years covered by these searches included 1980 to 2008. Results: Patients with HIV infection are at an increased risk of psychiatric illness. Major depressive disorder and subsyndromal depressive symptoms, as well as anxiety disorder and substance abuse are more prevalent among HIV infected individuals than among the general population. HIV-associated neurocognitive disorders (HAND) are common among HIV patients, and HIV-associated dementia (HAD) is a serious condition during the acquired immune deficiency syndrome (AIDS) stage of HIV disease. Secondarymania and psychosis might be the first clinical symptom of HIV dementia. The introduction of highly active anti-retroviral therapy (HAART) has resulted in significant decreases in morbidity and mortality for HIV infected patients. HAART has also decreased the incidence of HAD, but does not give complete protection from this condition. The utility of psychotropic medications in HIV patients has not been studied sufficiently as a basis for guidelines, and more controlled trials are needed. Conclusion: Psychiatric illness is common in HIV infected individuals, and underlines the importance for screening not only for cognitive impairment but also forco morbid mental disease in HIV-positive patients. Further studies of the neuropsychiatric complications during HIV disease and the use of psychotropics under these circumstances are clearly needed. A better understanding of the pathogenesis of HAD is essential to identify additional therapeutic strategies for prevention and treatment of this neurodegenerative disease. Studies are also needed for optimizing effective utilization of antiretrovirals into the CNS. Mania and psychosis secondary to HAD may be used as an indicator to initiate HAART, irrespective of CD4 count. Further research on the utility of HAART in the treatment of such acute neuropsychiatric symptoms associated with HIV infection should be initiated