Magneto-optical stokes polarimetry and nanostructured magnetic materials.

Stokes parameters fully characterize the polarization state of light in an experimentally accessible manner. Photoelastic modulator (PEM) based Stokes polarimetry offers a very high sensitivity which is particularly suitable for the investigation of the magneto-optical properties of nanostructured magnetic materials. In this paper, we shall describe a robust methodology recently developed by us that utilizes a dual PEM setup. As an example of its application, we report on the magneto-optical characteristics of focused Ga ion beam patterned Fe films. We have investigated Ga ion irradiation of single-layer polycrystalline Fe films deposited on Si3N4 substrates, which allows us to study the effects of ion implantation with minimum added complications. Complemented by structural and other characterization techniques, the absolute measurement of magneto-optical effects through the determination of Stokes parameters has enabled us to effectively separate the various contributions from film thinning due to sputtering, structural modifications and compositional changes caused by Ga incorporation. A comparison is also made between the magneto-optical behavior of patterned thin films and that of anodic aluminum oxide embedded magnetic nanowire arrays.

Deaths from violence in North Carolina, 2004: how deaths differ in females and males.

OBJECTIVE: To identify gender differences in violent deaths in terms of incidence, circumstances, and methods of death. DESIGN: Analysis of surveillance data. SETTING: North Carolina, a state of 8.6 million residents on the eastern seaboard of the US. SUBJECTS: 1674 North Carolina residents who died from violence in the state during 2004. METHODS: Information on violent deaths was collected by the North Carolina Violent Death Reporting System using data from death certificates, medical examiner reports, and law enforcement agency incidence reports. RESULTS: Suicide and homicide rates were lower for females than males. For suicides, females were more likely than males to have a diagnosis of depression (55% v 36%), a current mental health problem (66% v 42%), or a history of suicide attempts (25% v 13%). Firearms were the sole method of suicide in 65% of males and 42% of females. Poisonings were more common in female than male suicides (37% v 12%). Male and female homicide victims were most likely to die from a handgun or a sharp instrument. Fifty seven percent of female homicides involved intimate partner violence, compared with 13% of male homicides. Among female homicides involving intimate partner violence, 78% occurred in the woman's home. White females had a higher rate of suicide than African-American females, but African-American females had a higher rate of homicide than white females. CONCLUSIONS: The incidence, circumstances, and methods of fatal violence differ greatly between females and males. These differences should be taken into account in the development of violence prevention efforts.

Risk factors among handgun retailers for frequent and disproportionate sales of guns used in violent and firearm related crimes.

OBJECTIVE: To determine the retailer and community level factors associated with frequent and disproportionate sales of handguns that are later used in violent and firearm related crimes (VFC handguns). DESIGN: Cross sectional. The authors used California records to identify all handguns sold by study subjects during 1996-2000 and federal gun tracing records to determine which of these guns had been recovered by a police agency in the US or elsewhere and traced by 30 September 2003. SUBJECTS AND SETTING: The 421 licensed gun retailers in California selling at least 100 handguns annually during 1996-2000. MAIN OUTCOME MEASURE: The number of VFC handguns per 1000 gun years of exposure. Differences are expressed as incidence rate ratios (RR) with 95% confidence intervals (CI). RESULTS: Subjects accounted for 11.7% of California retailers with handgun sales, 81.5% of handgun sales, and 85.5% of VFC handguns. Among subjects, the 3426 VFC handguns accounted for 48.0% of all traced handguns and 65.0% of those linked to a specified crime. The median VFC handgun trace rate was 0.5/1000 gun years (range 0-8.8). In multivariate analysis, this rate increased substantially for each single-point increase in the percentage of proposed sales that were denied because the purchasers were prohibited from owning guns (RR 1.43; 95% CI 1.32 to 1.56), and was increased for pawnbrokers (RR 1.26; 95% CI 1.02 to 1.55). Community level crime rates and sociodemographics had little predictive value. CONCLUSIONS: Risk factors, largely determined at the retailer level, exist for frequent and disproportionate sales of handguns that are later used in violent and firearm related crimes. Screening to identify high risk retailers could be undertaken with data that are already available.

Aspergillus clavatus tremorgenic neurotoxicosis in cattle fed sprouted grains.

Beef and dairy cattle from four different herds in southern and central Queensland fed hydroponically-produced sprouted barley or wheat grain heavily infested with Aspergillus clavatus developed posterior ataxia with knuckling of fetlocks, muscular tremors and recumbency, but maintained appetite. A few animals variously had reduced milk production, hyperaesthesia, drooling of saliva, hypermetria of hind limbs or muscle spasms. Degeneration of large neurones was seen in the brain stem and spinal cord grey matter. The syndrome was consistent with A clavatus tremorgenic mycotoxicosis of ruminants. The cases are the earliest known to be associated with this fungus in Australia. They highlight a potential hazard of hydroponic fodder production systems, which appear to favour A clavatus growth on sprouted grain, exacerbated in some cases by equipment malfunctions that increase operating temperatures.

Measurement system for systematic hydrological characterization of unsaturated fractured welded tuff in a mined underground tunnel.

A field investigation of unsaturated flow through a lithophysal unit of fractured welded tuff containing lithophysal cavities has been initiated. To characterize flow in this spatially heterogeneous medium, a systematic approach has been developed to perform tests in boreholes drilled at regular intervals in an underground tunnel (drift). The purpose of the testing is to quantify the amounts of water seeping into the drift versus the amount of water moving around the drift when released into boreholes at many equidistant locations along the drift. In this paper, we describe the test equipment system that has been built for this purpose. Because the field-scale measurements--of liquid flow in the unsaturated, fractured rocks--require continuous testing for periods of days to weeks, the control of test equipment has been fully automated, allowing operation with no human presence at the field site. Preliminary results from the first set of tests indicate that, while the effects of evaporation on characterization of hydrological properties of the rock can be significant, these effects can be controlled and quantified. These tests give insight into the role of the cavities as potential storage during the initial transient flow prior to the breakthrough of water at the drift crown, as well as the role of connected fractures that provide the subsequent quasi-steady flow. In addition to the stated purpose of realizing the flow partitioning, the results yield values for the effective porosity in the pathways for liquid flow in the regions tested thus far.

Inverse and predictive modeling of seepage into underground openings.

We discuss the development and calibration of a model for predicting seepage into underground openings. Seepage is a key factor affecting the performance of the potential nuclear-waste repository at Yucca Mountain, Nevada. Three-dimensional numerical models were developed to simulate field tests in which water was released from boreholes above excavated niches. Data from air-injection tests were geostatistically analyzed to infer the heterogeneous structure of the fracture permeability field. The heterogeneous continuum model was then calibrated against the measured amount of water that seeped into the opening. This approach resulted in the estimation of model-related, seepage-specific parameters on the scale of interest. The ability of the calibrated model to predict seepage was examined by comparing calculated with measured seepage rates from additional experiments conducted in different portions of the fracture network. We conclude that an effective capillary strength parameter is suitable to characterize seepage-related features and processes for use in a prediction model of average seepage into potential waste-emplacement drifts.

Purulent and constrictive pericarditis arising from a staphylococcal lumbar infection.

A 78-year-old man was admitted to the hospital for evaluation and treatment of anasarca secondary to staphylococcal purulent pericarditis. One month earlier he had undergone a lumbar laminectomy that was complicated postoperatively by a lumbar abscess that was not clinically apparent. The infection subsequently spread to the pericardium. Despite aggressive therapy that included therapeutic pericardiocentesis, drainage of pericardial fluid, and prolonged intravenous antibiotic therapy, the patient returned 2 weeks after discharge from the hospital with complicating constrictive pericarditis. Pericardiectomy was performed, resulting in complete relief of the patient's symptoms.

Homicide and suicide rates associated with implementation of the Brady Handgun Violence Prevention Act.

CONTEXT: In February 1994, the Brady Handgun Violence Prevention Act established a nationwide requirement that licensed firearms dealers observe a waiting period and initiate a background check for handgun sales. The effects of this act have not been analyzed. OBJECTIVE: To determine whether implementation of the Brady Act was associated with reductions in homicide and suicide rates. DESIGN AND SETTING: Analysis of vital statistics data in the United States for 1985 through 1997 from the National Center for Health Statistics. MAIN OUTCOME MEASURES: Total and firearm homicide and suicide rates per 100,000 adults (>/=21 years and >/=55 years) and proportion of homicides and suicides resulting from firearms were calculated by state and year. Controlling for population age, race, poverty and income levels, urban residence, and alcohol consumption, the 32 "treatment" states directly affected by the Brady Act requirements were compared with the 18 "control" states and the District of Columbia, which had equivalent legislation already in place. RESULTS: Changes in rates of homicide and suicide for treatment and control states were not significantly different, except for firearm suicides among persons aged 55 years or older (-0.92 per 100,000; 95% confidence interval [CI], -1.43 to -0.42). This reduction in suicides for persons aged 55 years or older was much stronger in states that had instituted both waiting periods and background checks (-1.03 per 100,000; 95% CI, -1.58 to -0.47) than in states that only changed background check requirements (-0.17 per 100,000; 95% CI, -1.09 to 0.75). CONCLUSIONS: Based on the assumption that the greatest reductions in fatal violence would be within states that were required to institute waiting periods and background checks, implementation of the Brady Act appears to have been associated with reductions in the firearm suicide rate for persons aged 55 years or older but not with reductions in homicide rates or overall suicide rates. However, the pattern of implementation of the Brady Act does not permit a reliable analysis of a potential effect of reductions in the flow of guns from treatment-state gun dealers into secondary markets. JAMA. 2000;284:585-591

The medical costs of gunshot injuries in the United States.

CONTEXT: The cost of treating gunshot injuries imposes a financial burden on society. Estimates of such costs are relevant to evaluation of gun violence reduction programs and may help guide reimbursement policies. OBJECTIVES: To develop reliable US estimates of the medical costs of treating gunshot injuries and to present national estimates for the sources of payment for treating these injuries. DESIGN AND SETTING: Cost analysis using E-coded discharge data from hospitals in Maryland for 1994-1995 and New York for 1994 and from emergency departments in South Carolina for 1997. Other sources of data included the National Electronic Injury Surveillance System for 1994 incidence of nonfatal gun injuries, the National Spinal Cord Injury Statistical Center database for 1988-1992 estimates of lifetime medical costs of gun injuries, and the 1994 Vital Statistics census for incidence of fatal gun injuries. MAIN OUTCOME MEASURES: Estimated national acute-care and follow-up treatment costs and payment sources for gunshot injuries. RESULTS: At a mean medical cost per injury of about $17000, the 134445 (95% confidence interval [CI], 109465-159425) gunshot injuries in the United States in 1994 produced $2.3 billion (95% CI, $2.1 billion-$2.5 billion) in lifetime medical costs (in 1994 dollars, using a 3% real discount rate), of which $1.1 billion (49%) was paid by US taxpayers. Gunshot injuries due to assaults accounted for 74% of total costs. CONCLUSIONS: Gunshot injury costs represent a substantial burden to the medical care system. Nearly half this cost is borne by US taxpayers.

The effects of short-term variation in abortion funding on pregnancy outcomes.

The appropriations for North Carolina's abortion fund have proven inadequate during five of the years between 1980 and 1994. This on-again, off-again funding pattern provides a natural experiment for estimating the short-run effect of changes in the cost of abortions on the number of abortions to indigent women. Using an unusually detailed dataset, we estimate the effects of funding termination on the monthly abortion and birth rates. Overall, approximately one-third of pregnancies that would have resulted in an abortion, had state funds been available, are instead carried to term.

Simplified preparation of human arterial sections for PCR analysis of Chlamydia pneumoniae and human DNA.

AIMS: To investigate multiple techniques for the preparation of solid tissue for polymerase chain reaction (PCR) analysis, and to identify the most simple techniques for routine use in the laboratory. METHODS: Techniques for the preparation of arterial tissue samples including homogenisation, ultrafiltration, and treatments involving proteinase K, Gene Clean, lectin, and Fe3+ specific chelators were evaluated using the PCR to amplify both Chlamydia pneumoniae and human DNA. RESULTS: Treatment with either Gene-Clean or lectin and the Fe3+ specific chelator deferoxamine mesylate removed PCR inhibitors from tissue homogenates. Homogenisation followed by GeneClean treatment resulted in the amplification of C pneumoniae DNA from within a section of atherosclerotic carotid artery, implying that C pneumoniae elementary bodies had been disrupted. In eight further clinical samples from patients not known to have C pneumoniae infection, human DNA was amplified and no cross contamination was observed between samples. These samples contained no evidence of C pneumoniae by PCR. CONCLUSIONS: A simple preparation of solid tissue for PCR analysis, involving homogenisation followed by GeneClean treatment has been developed, and is effective for the amplification of both C pneumoniae and human DNA.

The gender gap in reporting household gun ownership.

OBJECTIVES: This study examined errors in estimating household gun ownership that result from interviewing only 1 adult per household. METHODS: Data from 2 recent telephone surveys and a series of in-person surveys were used to compare reports of household gun ownership by husbands and wives. RESULTS: In the telephone surveys, the rate of household gun ownership reported by husbands exceeded wives' reports by an average of 12 percentage points; husbands' reports also implied 43.3 million more guns. The median "gender gap" in recent in-person surveys is 7 percentage points. CONCLUSIONS: Future research should focus on respondents' reports about personally owned guns.

Chlamydia pneumoniae infection and ethnic origin

OBJECTIVES: To test the association of Chlamydia pneumoniae infection with ethnic origin. DESIGN: A prospective study by micro-immunofluorescence of antibodies to C. pnuemoniae in patients admitted to one hospital with a variety of non-pulmonary, non-cardiovascular disorders. SETTING: A large district general hospital serving a multi-ethnic inner-city population in Birmingham, UK. SUBJECTS: There were 1518 patients, 1061 of whom were Caucasian, 290 Asian and 167 Afro-Caribbean. Each of 169 Asian and 141 Afro-Caribbeans was matched with two Caucasians for age, sex, smoking habit, steriod medication and date of admission, and logistic regression methods were used to compared the effects on C. pneumoniae antibody levels of ethnic origin, these confounding variables, diabetes mellitus and social deprivation. OUTCOME MEASURES: Serological evidence of acute C. pnuemoniae infection or reinfection (defined by titres of IgM > or = 8, a four-fold rise in IgG or IgG > or = 512) and previous infection (IgG 64-256 or IgA > or = 8). RESULTS: Results showed 4.8 percent of Caucasians, 6.6 percent of Asians and 10.2 percent of Afro-Caribbeans had antibody titres suggesting acute (re) infection; and 11.2 percent of Caucasians, 13.4 percent Asians and 21.0 percent of Afro-Caribbeans had titres suggesting previous infection. On chi 2 analysis, the distributions of the three possible serological outcomes (acute, previous and no infection) differed significantly (p < 0.05) between the Afro-Caribbean and Caucasian groups, but not between Asians and Caucasians or between Afro-Caribbeans and Asians. After adjusting for possible confounding variables, odds ratios for Afro-Caribbean versus Caucasian origin were 5.5 (95 percent confidence intervals 2.0-15.0) for acute (re) infection and 1.9 (1.0-3.7) for previous infection. CONCLUSION: Our results suggest that C. pneumoniae infection may be more prevalent among Afro-Caribbean than among Caucasian people, and that Asians may lie somewhere them in this respect. The behaviour of this pathogen in different ethnic groups deserve further investigation. Future studies of this organism should give due attention to the ethnic origins of patients.(AU)

Chlamydia pneumoniae and asthma.

BACKGROUND: This study was designed to test the association of Chlamydia pneumoniae infection with asthma in a multi-racial population, after adjustments for several potential confounding variables. METHODS: Antibodies to C pneumoniae were measured by microimmunofluorescence in 123 patients with acute asthma, 1518 control subjects admitted to the same hospital with various non-cardiovascular, non-pulmonary disorders, and 46 patients with severe chronic asthma, including some with "brittle" asthma. Acute infection or reinfection was defined by titres of IgG of > or = 512 or IgM > or = 8 or a fourfold rise in IgG, and previous infection by IgG 64-256 or IgA > or = 8. Logistic regression was used to control for likely confounders, including ethnic origin, age, sex, smoking habit, steroid medication, diabetes mellitus and social deprivation, on antibody levels. RESULTS: Antibody titres consistent with acute C pneumoniae infection were found in 5.7% of patients with acute asthma and 5.7% of control patients, while 14.6% of patients with acute asthma and 12.7% of control patients had titres suggesting previous infection. These two groups did not differ significantly. However, titres suggesting previous infection were found in 34.8% of patients with severe chronic asthma: the difference between this group and the control group was statistically significant with an adjusted odds ratio of 3.99 (95% confidence interval 1.60 to 9.97). CONCLUSIONS: These data raise important questions about the previously demonstrated association of C pneumoniae infection with asthma, and suggest that future studies of this association should give particular attention to the presence or absence of a history of severe chronic asthma.

Support for new policies to regulate firearms. Results of two national surveys.

BACKGROUND: New policy options are emerging in the debate regarding the regulation of firearms in the United States. These options include the treatment of firearms as consumer products, the design of which can be regulated for safety; denial of gun ownership to those convicted of misdemeanors; and strategies to curtail the illegal sale of guns. The public's opinion of these innovative gun-policy options has not been thoroughly assessed. METHODS: We conducted two telephone surveys of 1200 adults each in the United States in 1996 and 1997-1998. Cognitive interviews and pretests were used in the development of the survey instruments. Potential participants were then contacted by random-digit dialing of telephone numbers. RESULTS: A majority of the respondents favored safety standards for new handguns. These standards included childproofing (favored by 88 percent of respondents), personalization (devices that permit firing only by an authorized person; 71 percent), magazine safeties (devices that prevent firing after the magazine or clip is removed; 82 percent), and loaded-chamber indicators (devices that show whether the handgun is loaded; 73 percent). There was strong support for policies prohibiting persons convicted of specific misdemeanors from purchasing a firearm. Support for such prohibitions was strongest for crimes involving violence or the illegal use of a firearm (83 to 95 percent) or substance abuse (71 to 92 percent). There was also widespread support for policies designed to reduce the illegal sale of guns, such as mandatory tamper-resistant serial numbers (90 percent), a limit of one handgun purchase per customer per month (81 percent), and mandatory registration of handguns (82 percent). Even among the subgroup of respondents who were gun owners, a majority were in favor of stricter gun regulations with regard to 20 of the 22 proposals covered in the poll. CONCLUSIONS: Strong public support, even among gun owners, for innovative strategies to regulate firearms suggests that these proposals warrant serious consideration by policy makers.

Chlamydia pneumoniae antibodies in severe essential hypertension.

Several studies have implied an association between Chlamydia pneumoniae (C. pneumoniae) and cardiovascular disease. Our study was designed to determine whether this organism is associated with severe essential hypertension in a multiracial British population. Antibodies to C. pneumoniae were measured by microimmunofluorescence in 123 patients with chronic severe hypertension and 123 control subjects, matched for ethnic origin, age, sex, and smoking habit, admitted to the same hospital with various noncardiovascular, nonpulmonary disorders. Previous infection was defined by IgG 64 to 256, provided that there was no detectable IgM. Multiple regression analyses of matched and unmatched data were used to investigate the influences of antibody levels and potential confounding factors (ethnic origin, age, sex, smoking habit, diabetes mellitus, and social deprivation) on hypertension. A portion of the hypertensive patients underwent echocardiography, estimation of left ventricular mass index, and measurements of fibrinogen, D-dimer, and von Willebrand factor concentrations. Thirty-five percent of hypertensive patients and 17.9% of matched control subjects had antibody titers consistent with previous C. pneumoniae infection. The hypertensive patients differed significantly from their matched control subjects in their level of previous infection, with an odds ratio of 2.5 (95% confidence interval, 1.3 to 4.7). There were no significant differences in antibody levels between patients with left ventricular hypertrophy and those without it. Fibrinogen, D-dimer, and von Willebrand factor concentrations were not significantly associated with antibody levels. These data support an association of C. pneumoniae with severe essential hypertension. They provide no evidence of a predisposition to develop left ventricular hypertrophy in hypertensive patients with C. pneumoniae infection or of associations with hypercoagulability or endothelial dysfunction.

Chlamydia pneumoniae antibody titers are significantly associated with acute stroke and transient cerebral ischemia: the West Birmingham Stroke Project.

BACKGROUND AND PURPOSE: Several studies have implied an association between Chlamydia pneumoniae and atherosclerosis. Our research was designed to investigate the association of this organism with strokes and transient cerebral ischemia. METHODS: Antibodies to C pneumoniae were measured in 176 patients with stroke or transient cerebral ischemia and 1518 control subjects with noncardiovascular, nonpulmonary disorders. Acute infection or reinfection was defined by IgG > or =512 or IgM > or =8 or fourfold rise in IgG, and previous infection was defined by IgG 64 to 256 or IgA > or =8. Logistic regression was used to examine the influences of ethnic origin, age, sex, smoking habit, diabetes mellitus, steroid medication, and social deprivation on antibody levels. Some patients underwent CT and carotid ultrasound examinations and cholesterol, triglyceride, fibrinogen, and von Willebrand factor estimations. RESULTS: We found that 13.6% of stroke/transient ischemic attack (TIA) patients and 5.7% of control subjects had antibody titers suggesting acute C pneumoniae (re)infection, while 32.4% of stroke/TIA patients and 12.7% of control subjects had titers suggesting previous infection (P<.05). Stroke/TIA patients differed from control subjects in their levels of acute and previous infection, with adjusted odds ratios of 4.2 (95% CI, 2.5 to 7.1) and 4.4 (95% CI, 3.0 to 6.5), respectively. These did not differ notably between strokes resulting from major nonhemorrhagic infarcts, small-vessel infarcts, or hemorrhage. Cholesterol, triglyceride, fibrinogen, and von Willebrand factor concentrations showed no apparent association with titers. CONCLUSIONS: These data support the association of cerebral vascular disease with previous C pneumoniae infection and the association of stroke and transient cerebral ischemia with recrudescence of infection.

Chlamydia pneumoniae infection and ethnic origin.

OBJECTIVES: To test the association of Chlamydia pneumoniae infection with ethnic origin. DESIGN: A prospective study by micro-immunofluorescence of antibodies to C. pneumoniae in patients admitted to one hospital with a variety of non-pulmonary, non-cardiovascular disorders. SETTING: A large district general hospital serving a multi-ethnic inner-city population in Birmingham, UK. SUBJECTS: There were 1518 patients, 1061 of whom were Caucasian, 290 Asian and 167 Afro-Caribbean. Each of 169 Asians and 141 Afro-Caribbeans was matched with two Caucasians for age, sex, smoking habit, steroid medication and date of admission, and logistic regression methods were used to compare the effects on C. pneumoniae antibody levels of ethnic origin, these confounding variables, diabetes mellitus and social deprivation. OUTCOME MEASURES: Serological evidence of acute C. pneumoniae infection or reinfection (defined by titres of IgM > or = 8, a four-fold rise in IgG or IgG > or = 512) and previous infection (IgG 64-256 or IgA > or = 8). RESULTS: Results showed 4.8% of Caucasians, 6.6% of Asians and 10.2% of Afro-Caribbeans had antibody titres suggesting acute (re)infection; and 11.2% of Caucasians, 13.4% of Asians and 21.0% of Afro-Caribbeans had titres suggesting previous infection. On chi 2 analysis, the distributions of the three possible serological outcomes (acute, previous and no infection) differed significantly (p < 0.05) between the Afro-Caribbean and Caucasian groups, but not between Asians and Caucasians or between Afro-Caribbeans and Asians. After adjusting for possible confounding variables, odds ratios for Afro-Caribbean versus Caucasian origin were 5.5 (95% confidence intervals 2.0-15.0) for acute (re)infection and 1.9 (1.0-3.7) for previous infection. CONCLUSIONS: Our results suggest that C. pneumoniae infection may be more prevalent among Afro-Caribbean than among Caucasian people, and that Asians may lie somewhere between them in this respect. The behaviour of this pathogen in different ethnic groups deserves further investigation. Future studies of this organism should give due attention to the ethnic origins of patients.

Infectious agents and atherosclerotic vascular disease.

The pathological changes underlying occlusive vascular disease show considerable overlap with those caused by a range of infections. Particular viral and bacterial pathogens have long been suspected of playing a part, directly or indirectly, in the process leading to atherosclerosis. We review recent evidence of links between infections and ischaemic heart disease, particularly in the case of Chlamydia pneumoniae infection. Possible mechanisms for these associations are discussed.