Experience with DAQ for ATLAS Semi-Conductor Tracker

The Semi-Conductor Tracker is a silicon strip tracker that forms part of the ATLAS detector at the LHC. The DAQ system is responsible for reading data from the detector for analysis. Recent experiences of commissioning and integration of the DAQ are described including problems and solutions

Investigating the intrinsic noise limit of Dayem bridge NanoSQUIDs

NanoSQUIDs made from Nb thin films have been produced with nanometre loop sizes down to 200 nm, using weak-link junctions with dimensions less than 60 nm. These composite (W/Nb) single layer thin film devices, patterned by FIB milling, show extremely good low-noise performance ∼170 nΦ0 at temperatures between 5 and 8.5 K and can operate in rather high magnetic fields (at least up to 1 T). The devices produced so far have a limited operating temperature range, typically only 1–2 K. We have the goal of achieving operation at 4.2 K, to be compatible with the best SQUID series array (SSA) preamplifier available. Using the SSA to readout the nanoSQUIDs provides us with a means of investigating the intrinsic noise of the former. In this paper we report improved white noise levels of these nanoSQUIDs, enabling potential detection of a single electronic spin flip in a 1-Hz bandwidth. At low frequencies the noise performance is already limited by SSA preamplifier noise

Attachment-based family therapy for adolescents with suicidal ideation: a randomized controlled trial.

OBJECTIVE: To evaluate whether Attachment-Based Family Therapy (ABFT) is more effective than Enhanced Usual Care (EUC) for reducing suicidal ideation and depressive symptoms in adolescents. METHOD: This was a randomized controlled trial of suicidal adolescents between the ages of 12 and 17, identified in primary care and emergency departments. Of 341 adolescents screened, 66 (70% African American) entered the study for 3 months of treatment. Assessment occurred at baseline, 6 weeks, 12 weeks, and 24 weeks. ABFT consisted of individual and family meetings, and EUC consisted of a facilitated referral to other providers. All participants received weekly monitoring and access to a 24-hour crisis phone. Trajectory of change and clinical recovery were measured for suicidal ideation and depressive symptoms. RESULTS: Using intent to treat, patients in ABFT demonstrated significantly greater rates of change on self-reported suicidal ideation at post-treatment evaluation, and benefits were maintained at follow-up, with a strong overall effect size (ES = 0.97). Between-group differences were similar on clinician ratings. Significantly more patients in ABFT met criteria for clinical recovery on suicidal ideation post-treatment (87%; 95% confidence interval [CI] = 74.6-99.6) than patients in EUC (51.7%; 95% CI = 32.4-54.32). Benefits were maintained at follow-up (ABFT, 70%; 95% CI = 52.6-87.4; EUC 34.6%; 95% CI = 15.6-54.2; odds ratio = 4.41). Patterns of depressive symptoms over time were similar, as were results for a subsample of adolescents with diagnosed depression. Retention in ABFT was higher than in EUC (mean = 9.7 versus 2.9). CONCLUSIONS: ABFT is more efficacious than EUC in reducing suicidal ideation and depressive symptoms in adolescents. Additional research is warranted to confirm treatment efficacy and to test the proposed mechanism of change (the Family Safety Net Study).Clinical Trial Registry Information: Preventing Youth Suicide in Primary Care: A Family Model, URL: http://www.clinicaltrials.gov, unique identifier: NCT00604097

Tunable coaxial cavity resonator for linear and nonlinear microwave characterization of superconducting wires

We discuss experimental results obtained using a tunable cylindrical coaxial cavity constituted by an outer Cu cylinder and an inner Pb-BSCCO wire. We have used this device for investigating the microwave response of the superconducting wire, both in the linear and nonlinear regimes. In particular, by tuning the different modes of the cavity to make them resonant at exactly harmonic frequencies, we have detected the power emitted by the superconducting inner wire at the second- and third-harmonic frequency of the driving field. The results obtained in the nonlinear regime, whether for the microwave surface impedance or the harmonic emission, are qualitatively accounted for considering intergrain fluxon dynamics. The use of this kind of device can be of strong interest to investigate and characterise wires of large dimensions to be used for implementing superconducting-based microwave devices.Comment: 14 pages, 6 embedded figures, accepted for publication in Supercond. Sci. Techno

Integrable Euler top and nonholonomic Chaplygin ball

We discuss the Poisson structures, Lax matrices, $r$-matrices, bi-hamiltonian structures, the variables of separation and other attributes of the modern theory of dynamical systems in application to the integrable Euler top and to the nonholonomic Chaplygin ball.Comment: 25 pages, LaTeX with AMS fonts, final versio

Endogenous networks and international cooperation

The rise of social network analyses in the social sciences has allowed empirical work to better account for interdependencies among actors and among their actions. However, this work has been, to a large extent, descriptive: it has treated these actions as exogenous and immutable. In many cases these networks describe actions like alliance formation or trade phenomena that are the outcome variables for programs of social scientific research. In this paper, I attempt to account for both interdependencies and the endogenous nature of networks by incorporating formal theory; helping answer the question of how these networks arise by looking at the incentives of actors to form links with each other. I discuss the appropriate solution concept for a network formation game, and present an algorithm for finding the equilibrium of these networks computationally as well as ways to compare the theoretical networks to observed ones in order to evaluate the fit of the theory. I apply these methods to the study of international cooperation a subject where both the interdependencies and purposive nature of actors must be accounted for. The theoretical network is able to reproduce a number of important observed characteristics. Still, there are more factors that must be accounted for if we want to understand how the network of international cooperation is formed

Bond-graph Input-State-Output Port-Hamiltonian formulation of memristive networks for emulation of Josephson junction circuits

A bond graph Input-State-Output Port-Hamiltonian formulation of memristive networks for Josephson junction circuits in state space is presented. The methodology has applications to the modeling of SQUIDs and other non-linear transducers and enables the formulation of input-output models of complex components embedded in non-linear networks

A double-sided silicon micro-strip super-module for the ATLAS inner detector upgrade in the high-luminosity LHC

The ATLAS experiment is a general purpose detector aiming to fully exploit the discovery potential of the Large Hadron Collider (LHC) at CERN. It is foreseen that after several years of successful data-taking, the LHC physics programme will be extended in the so-called High-Luminosity LHC, where the instantaneous luminosity will be increased up to 5 × 1034 cm−2 s−1. For ATLAS, an upgrade scenario will imply the complete replacement of its internal tracker, as the existing detector will not provide the required performance due to the cumulated radiation damage and the increase in the detector occupancy. The current baseline layout for the new ATLAS tracker is an all-silicon-based detector, with pixel sensors in the inner layers and silicon micro-strip detectors at intermediate and outer radii. The super-module is an integration concept proposed for the strip region of the future ATLAS tracker, where double-sided stereo silicon micro-strip modules are assembled into a low-mass local support structure. An electrical super-module prototype for eight double-sided strip modules has been constructed. The aim is to exercise the multi-module readout chain and to investigate the noise performance of such a system. In this paper, the main components of the current super-module prototype are described and its electrical performance is presented in detail

Prototyping of petalets for the Phase-II Upgrade of the silicon strip tracking detector of the ATLAS Experiment

In the high luminosity era of the Large Hadron Collider, the HL-LHC, the instantaneous luminosity is expected to reach unprecedented values, resulting in about 200 proton-proton interactions in a typical bunch crossing. To cope with the resultant increase in occupancy, bandwidth and radiation damage, the ATLAS Inner Detector will be replaced by an all-silicon system, the Inner Tracker (ITk). The ITk consists of a silicon pixel and a strip detector and exploits the concept of modularity. Prototyping and testing of various strip detector components has been carried out. This paper presents the developments and results obtained with reduced-size structures equivalent to those foreseen to be used in the forward region of the silicon strip detector. Referred to as petalets, these structures are built around a composite sandwich with embedded cooling pipes and electrical tapes for routing the signals and power. Detector modules built using electronic flex boards and silicon strip sensors are glued on both the front and back side surfaces of the carbon structure. Details are given on the assembly, testing and evaluation of several petalets. Measurement results of both mechanical and electrical quantities are shown. Moreover, an outlook is given for improved prototyping plans for large structures.Comment: 22 pages for submission for Journal of Instrumentatio

On waiting for something to happen

This paper seeks to examine two particular and peculiar practices in which the mediation of apparently direct encounters is made explicit and is systematically theorized: that of the psychoanalytic dialogue with its inward focus and private secluded setting, and that of theatre and live performance, with its public focus. Both these practices are concerned with ways in which “live encounters” impact on their participants, and hence with the conditions under which, and the processes whereby, the coming-together of human subjects results in recognizable personal or social change. Through the rudimentary analysis of two anecdotes, we aim to think these encounters together in a way that explores what each borrows from the other, the psychoanalytic in the theatrical, the theatrical in the psychoanalytic, figuring each practice as differently committed to what we call the “publication of liveness”. We argue that these “redundant” forms of human contact continue to provide respite from group acceptance of narcissistic failure in the post-democratic era through their offer of a practice of waiting