Active noise barrier minimizing pressure gradient

Minimization of the sound pressure field within the shadow zone of a noise barrier is achieved by reducing the pressure gradient along a line, at the top of a barrier, via active noise control. The noise control effectiveness of a barrier is increased by this strategy, especially for specific system configurations. The proposed method was evaluated by numerical simulation. Results indicate that system orientation has little effect on minimizing the pressure gradient at the top of the barrier when the error sensors are invisible to the primary noise disturbance. Highly effective control within the shadow zone and close to the barrier is possible when the system is oriented at an angle where two or more error sensors are in line with the first diffracting edge and the primary noise disturbance. Increasing the spatial extent of the quiet zone is possible by increasing the number of control sources, where the error sensors have a line of sight with the primary noise disturbance

Methamphetamine: Fact vs. Fiction and Lessons from the Crack Hysteria

The purpose of this report is to provide a critical examination of the available evidence on illicit methamphetamine use and its consequences in the United States and internationally. It is the aim of this report to dispel some of the myths about the effects of methamphetamine and other illicit drugs using the best available scientific data. Further, it is our hope that this analysis will lead to more rational policies for dealing with both legal and illegal amphetamine. The report begins with an examination of the lessons learned from the "crack cocaine scare" in the 1980s. In this way, the reader can draw parallels between society's response to crack cocaine then, and methamphetamine now. The report then describes distinctions and similarities between methamphetamine and other amphetamine-type stimulants. Also examined is the prevalence of methamphetamine use and public policies in response to the perceived increased use of the drug and perceived drug-related problems. Finally, the report critically reviews the scientific literature on the effects of methamphetamine on the brain, physiology, and behavior. The data show that many of the immediate and long-term harmful effects caused by methamphetamine use have been greatly exaggerated just as the dangers of crack cocaine were overstated nearly three decades ago. Recommendations are made in an effort to remedy this situation and to enhance public health and safety

Return-to-work support for workers with mental health problems: identifying and responding to key challenges of sick leave

Introduction This research explored return-to-work and sick leave experiences of workers with mental health issues in contact with acute or community mental health services. Method Using a critical realist methodology with a comparative case study and collaborative design, 21 employed participants recovering from mental health problems participated in semi-structured interviews. Data were analysed using inductive and deductive thematic and constant comparative analysis. Findings While on sick leave, despite a range of challenges, participants treasured their work identities. They were sustained by positive and troubled by negative memories of work. People missed the routine of work and felt isolated. To varying degrees of success, they searched for alternative activities to fill this gap and promote recovery. Conclusion The need for sick leave was not disputed, but an important discovery was its iatrogenic (‘side-’) effects, whereby isolation and reduced activity levels could exacerbate mental health problems. Negative impacts of sick leave need to be mitigated by support to maintain worker identity and orientation and by opportunities and encouragement to sustain routine, activities and social contacts. A new concept of ‘occupational capital’ emerged, comprising accessible external opportunities and supports for occupational participation, and internal capacities and skills required to access these. </jats:sec

Mechanisms of improvement of respiratory failure in patients with COPD treated with NIV

Annabel H Nickol1,2, Nicholas Hart1,3, Nicholas S Hopkinson1, Carl-Hugo Hamneg&amp;aring;rd4, John Moxham5, Anita Simonds1, Michael I Polkey11Respiratory Muscle Laboratory, Royal Brompton Hospital, London, UK; 2Oxford Centre for Respiratory Medicine, Churchill Hospital, Oxford, UK; 3The Lane Fox Unit, St Thomas&amp;rsquo; Hospital, London, UK; 4Department of Pulmonary Medicine and Clinical Physiology, Sahlgrenska University, Gotenborg, Sweden; 5Respiratory Muscle Laboratory, King&amp;rsquo;s College London School of Medicine, King&amp;rsquo;s College Hospital, London, UKBackground: Noninvasive ventilation (NIV) improves gas-exchange and symptoms in selected chronic obstructive pulmonary disease (COPD) patients with hypercapnic respiratory failure. We hypothesized NIV reverses respiratory failure by one or all of increased ventilatory response to carbon-dioxide, reduced respiratory muscle fatigue, or improved pulmonary mechanics.Methods: Nineteen stable COPD patients (forced expiratory volume in one second 35% predicted) were studied at baseline (D0), 5&amp;ndash;8 days (D5) and 3 months (3M) after starting NIV.Results: Ventilator use was 6.2 (3.7) hours per night at D5 and 3.4 (1.6) at 3M (p = 0.12). Mean (SD) daytime arterial carbon-dioxide tension (PaCO2) was reduced from 7.4 (1.2) kPa to 7.0 (1.1) kPa at D5 and 6.5 (1.1) kPa at 3M (p = 0.001). Total lung capacity decreased from 107 (28) % predicted to 103 (28) at D5 and 103 (27) % predicted at 3M (p = 0.035). At D5 there was an increase in the hypercapnic ventilatory response and some volitional measures of inspiratory and expiratory muscle strength, but not isolated diaphragmatic strength whether assessed by volitional or nonvolitional methods.Conclusion: These findings suggest decreased gas trapping and increased ventilatory sensitivity to CO2 are the principal mechanism underlying improvements in gas-exchange in patients with COPD following NIV. Changes in some volitional but not nonvolitional muscle strength measures may reflect improved patient effort.Keywords: COPD; hypercapnic respiratory failure; NIV; pulmonary mechanics; ventilatory driv

Racial Justice Requires Ending the War on Drugs

Historically, laws and policies to criminalize drug use or possession were rooted in explicit racism, and they continue to wreak havoc on certain racialized communities. We are a group of bioethicists, drug experts, legal scholars, criminal justice researchers, sociologists, psychologists, and other allied professionals who have come together in support of a policy proposal that is evidence-based and ethically recommended. We call for the immediate decriminalization of all so-called recreational drugs and, ultimately, for their timely and appropriate legal regulation. We also call for criminal convictions for nonviolent offenses pertaining to the use or possession of small quantities of such drugs to be expunged, and for those currently serving time for these offenses to be released. In effect, we call for an end to the “war on drugs.

Zinc Finger Protein, Hzf, Is Required for Megakaryocyte Development and Hemostasis

Using an expression gene trapping strategy, we recently identified a novel gene, hematopoietic zinc finger (Hzf), which encodes a protein containing three C2H2-type zinc fingers that is predominantly expressed in megakaryocytes. Here, we have examined the in vivo function of Hzf by gene targeting and demonstrated that Hzf is essential for megakaryopoiesis and hemostasis in vivo. Hzf-deficient mice exhibited a pronounced tendency to rebleed and had reduced α-granule substances in both megakaryocytes and platelets. These mice also had large, faintly stained platelets, whereas the numbers of both megakaryocytes and platelets were normal. These results indicate that Hzf plays important roles in regulating the synthesis of α-granule substances and/or their packing into α-granules during the process of megakaryopoiesis