Sensation seeking and executive deficits in relation to alcohol, tobacco, and marijuana use frequency among university students: Value of ecologically based measures.

Introduction: The development of substance use and addiction has been linked to impaired executive function which relies on systems that converge in the prefrontal cortex. This study examined several measures of executive function as predictors of college student alcohol, tobacco, and marijuana use frequency and abuse.

Methods: College students (N=321) were administered the Delis-Kaplan Executive Function System (D-KEFS) test battery, the Sensation Seeking Scale V (SSSV), the Frontal Systems Behavioral Scale (FrSBe), the Perceived Stress Scale (PSS), the Michigan Alcohol Screening Test (MAST), the Fagerstrom Test of Nicotine Dependence (FTND).

Megavoltage quality control, resources and demand: a pragmatic review.

Objective: Satisfactory radiotherapy treatment requires quality control (QC) of the equipment as well as patient-specific checks. Increased complexity and extended use of equipment plus greater demand for complex treatment has brought pressure on QC resources. The benefits of integrating patient-specific checks and QC and the efficient use of resources is examined.

IGRT/ART phantom with programmable independent rib cage and tumor motion.

Purpose: This paper describes the design and experimental evaluation of the Methods and Advanced Equipment for Simulation and Treatment in Radiation Oncology (MAESTRO) thorax phantom, a new anthropomorphic moving ribcage combined with a 3D tumor positioning system to move target inserts within static lungs.

Methods: The new rib cage design is described and its motion is evaluated using Vicon Nexus, a commercial 3D motion tracking system. CT studies at inhale and exhale position are used to study the effect of rib motion and tissue equivalence.

Couch-based motion compensation: modelling, simulation and real-time experiments.

The paper presents a couch-based active motion compensation strategy evaluated in simulation and validated experimentally using both a research and a clinical Elekta Precise Table™. The control strategy combines a Kalman filter to predict the surrogate motion used as a reference by a linear model predictive controller with the control action calculation based on estimated position and velocity feedback provided by an observer as well as predicted couch position and velocity using a linearized state space model. An inversion technique is used to compensate for the dead-zone nonlinearity.

Hallucinogens as hard science: the adrenochrome hypothesis for the biogenesis of schizophrenia.

Working in a psychiatrically innovative environment created by the Government of Saskatchewan, Canada, Abram Hoffer and Humphry F. Osmond enunciated the adrenochrome hypothesis for the biogenesis of schizophrenia in 1952, slightly later proposing and, apparently, demonstrating, in a double-blind study, that the symptoms of the illness could be reversed by administering large doses of niacin. After placing the hypothesis within its ideological framework, the author describes its emergence and elaboration and discusses the empirical evidence brought against it.

An analysis of the origin of differences between measured and simulated fields produced by a 15-element ultrasound phased array.

Modeling provides an attractive approach for the design of phased array ultrasound transducers for hyperthermia. However, measurements on physical transducers reveal differences from the idealized field profiles predicted by simulation. In this paper we report a method of analyzing the origins of these differences.

Trust amply recompensed: psychological research at Weyburn, Saskatchewan, 1957-1961.

During the 1950s and 1960s professionals intensely debated the prospect of changes in the mental health system, largely as a result of the introduction of new therapies, revised theories of mental disorder, and shifting policies governing mental health accommodation. As well as giving rise to new subspecialties within medicine, psychiatrists in some jurisdictions at this time worked closely with psychologists in an attempt to offer a more comprehensive set of options that merged theory with practice. In Saskatchewan, mental health professionals worked closely with government officials and bureaucrats and produced a variety of innovative strategies that addressed changing priorities in this system.

Lessons from the periphery: psychiatry in Saskatchewan, Canada, 1944-68.

The government of the Saskatchewan Co-Operative Commonwealth Federation, when elected in 1944, established programmes for the state-funded care of all those suffering from mental illness. It enacted legislation covering the care and treatment of the mentally ill and created a division of the Department of Public Health, the Psychiatric Services Branch (PSB), which both recruited and trained psychiatric staff, meeting the need for nonmedical staff by creating a programme for the training of psychiatric nurses in Saskatchewan. The PSB devised the Saskatchewan Plan for the delivery of rural services, centred on small mental hospitals of a revolutionary design.

The design and characterization of an ultrasound phased array suitable for deep tissue hyperthermia.

In this paper we describe the design and evaluation of a planar phased-array ultrasound transducer suitable for producing localized hyperthermia in solid tumors deep within the body. Simulation using a customized version of Ultrasim has been used to determine the relationship between the size and position of the focus and parameters of the array. These parameters include the overall size of the array and the size, shape and distribution of the individual elements.

An assessment of GafChromic film for measuring 50 kV and 100 kV percentage depth dose curves.

Percentage depth dose (PDD) curves were obtained for 50 kV and 100 kV x-rays on a Gulmay Medical D3000 DXR unit. Different dosimetry systems were compared including a Scanditronix Wellhofer small volume cylindrical ion chamber, a Wellhofer photon PFD diode, a PTW soft x-ray parallel plate chamber (N23342) and two types of radiochromic film: GafChromic EBT and GafChromic MD55. The PDD curves were also compared to BEAMnrc Monte Carlo predictions.

A multiple model approach to respiratory motion prediction for real-time IGRT.

Respiration induces significant movement of tumours in the vicinity of thoracic and abdominal structures. Real-time image-guided radiotherapy (IGRT) aims to adapt radiation delivery to tumour motion during irradiation. One of the main problems for achieving this objective is the presence of time lag between the acquisition of tumour position and the radiation delivery.

A new approach to quantify the mechanical and radiation isocentres of radiotherapy treatment machine gantries.

In this paper a new method is proposed to quantify and reduce the radiation beam position uncertainty due to the radiotherapy treatment machine gantry deflection. A new tool has been designed and manufactured to provide the means to measure the alignment of the collimator axis and of the beam central axis in space, using the NDI Polaris optical tracking system and Gafchromic films. The tool can be mounted onto the accessory tray of the linacs from different manufacturers.

John Rickman, Wilfred Ruprecht Bion, and the origins of the therapeutic community.

The history of psychiatric therapeutic communities is complex and obscure. Nevertheless, one can make a reasonable case for saying that the first true therapeutic community was created at Northfield Military Hospital, Birmingham, England, in 1945. That community had its origins in the thought and practice of two British psychoanalysts, John Rickman and Wilfred Ruprecht Bion.