Acoustic and vibration isolation for a gravity gradiometer.

Vibration in the audio frequency band affects the performance of rotating gravity gradiometers used for airborne mineral exploration. This is probably due to translation to rotation coupling inside the gradiometer platform. It was found that the DC gravity gradient signal was proportional to the square of the third time derivative of position, or jerk squared. The demanding airborne environment for such instrumentation demands a light weight broadband acoustic shield and vibration isolator. This paper presents the design principles for such an isolator, based on vibration isolated spherical shell structures. Performance data are presented as well as flight test data that demonstrated a 14% gravity gradient noise reduction compared with an unshielded instrument.

Rotational isolation with neutrally buoyant suspension.

Rotational vibration isolation is of critical importance for many airborne instrumentation applications. Such isolators require very low frequency isolation for the rotational degrees of freedom combined with translational rigidity and negligible translation to rotation coupling. This paper describes a vibration isolator using neutrally buoyant flotation to provide high translation rigidity combined with very low rotational rigidity. The isolator reduces the rotational vibration at all frequencies above its resonance (0.18 ± 0.01 Hz) and has a large dynamic range (±30°) suitable for airborne surveying. Viscous, inviscid, and mechanical coupling inside the isolator have been analyzed. A recent fixed wing flight test shows the isolator reducing the rotational vibration by more than a factor of 1000 at frequencies above 10 Hz.

Animal Abuse and Interpersonal Violence: The Cruelty Connection and Its Implications for Veterinary Pathology.

The role of the veterinary forensic pathologist in the investigation of animal abuse or neglect can go beyond documenting the condition of animals presented as evidence. Although animal cruelty is a moral concern and a crime in itself, law enforcement response to such crimes is often enhanced by the recognition that crimes against animals can be both indicators of other ongoing crimes against people and predictors of the potential for interpersonal violence. An understanding of common motives underlying animal cruelty can aid the pathologist in asking appropriate questions. The authors review the forms of pathology evidence commonly seen in various presentations of animal cruelty. Understanding these forms of evidence can help the pathologist describe findings that can be significant for assessing the potential risks the alleged perpetrator may pose to other animals and humans.

Early mobilisation after conventional knee replacement may reduce the risk of postoperative venous thromboembolism.

We carried out an audit on the result of achieving early walking in total knee replacement after instituting a new rehabilitation protocol, and assessed its influence on the development of deep-vein thrombosis as determined by Doppler ultrasound scanning on the fifth post-operative day. Early mobilisation was defined as beginning to walk less than 24 hours after knee replacement. Between April 1997 and July 2002, 98 patients underwent a total of 125 total knee replacements. They began walking on the second post-operative day unless there was a medical contraindication. They formed a retrospective control group. A protocol which allowed patients to start walking at less than 24 hours after surgery was instituted in August 2002. Between August 2002 and November 2004, 97 patients underwent a total of 122 total knee replacements. They formed the early mobilisation group, in which data were prospectively gathered. The two groups were of similar age, gender and had similar medical comorbidities. The surgical technique and tourniquet times were similar and the same instrumentation was used in nearly all cases. All the patients received low-molecular-weight heparin thromboprophylaxis and wore compression stockings post-operatively. In the early mobilisation group 90 patients (92.8%) began walking successfully within 24 hours of their operation. The incidence of deep-vein thrombosis fell from 27.6% in the control group to 1.0% in the early mobilisation group (chi-squared test, p < 0.001). There was a difference in the incidence of risk factors for deep-vein thrombosis between the two groups. However, multiple logistic regression analysis showed that the institution of an early mobilisation protocol resulted in a 30-fold reduction in the risk of post-operative deep-vein thrombosis when we adjusted for other risk factors.

Benchmarking applications: linking state strategic planning, quality improvement, and consumer reporting.

This article demonstrates the value of using benchmark patient satisfaction data for Medicaid program quality improvement. The authors compare surveys of Maryland Medicaid and federal employees in Maryland, utilizing the latter as an external benchmark. Unadjusted and adjusted analyses found a significantly lower percentage of Medicaid than federal respondents rated telephone access excellent, very good, or good, whereas more Medicaid respondents rated advice on prevention and choice of primary care doctor highly. Patient satisfaction external benchmark data provide managed care organizations (MCOs) and state policy makers with goals to improve quality and standards to measure care objectively in vulnerable populations.

Breeds of dogs involved in fatal human attacks in the United States between 1979 and 1998.

OBJECTIVE: To summarize breeds of dogs involved in fatal human attacks during a 20-year period and to assess policy implications. ANIMALS: Dogs for which breed was reported involved in attacks on humans between 1979 and 1998 that resulted in human dog bite-related fatalities (DBRF). PROCEDURE: Data for human DBRF identified previously for the period of 1979 through 1996 were combined with human DBRF newly identified for 1997 and 1998. Human DBRF were identified by searching news accounts and by use of The Humane Society of the United States' registry databank. RESULTS: During 1997 and 1998, at least 27 people died of dog bite attacks (18 in 1997 and 9 in 1998). At least 25 breeds of dogs have been involved in 238 human DBRF during the past 20 years. Pit bull-type dogs and Rottweilers were involved in more than half of these deaths. Of 227 reports with relevant data, 55 (24%) human deaths involved unrestrained dogs off their owners' property, 133 (58%) involved unrestrained dogs on their owners' property, 38 (17%) involved restrained dogs on their owners' property, and 1 (< 1%) involved a restrained dog off its owner's property. CONCLUSIONS: Although fatal attacks on humans appear to be a breed-specific problem (pit bull-type dogs and Rottweilers), other breeds may bite and cause fatalities at higher rates. Because of difficulties inherent in determining a dog's breed with certainty, enforcement of breed-specific ordinances raises constitutional and practical issues. Fatal attacks represent a small proportion of dog bite injuries to humans and, therefore, should not be the primary factor driving public policy concerning dangerous dogs. Many practical alternatives to breed-specific ordinances exist and hold promise for prevention of dog bites.

Natural history of median nerve sensory conduction in industry: relationship to symptoms and carpal tunnel syndrome in 558 hands over 11 years.

We evaluated the natural history of median nerve sensory conduction, hand/wrist symptoms, and carpal tunnel syndrome (CTS) in an 11-year longitudinal study of 289 workers from four industries. Twenty hands which had carpal tunnel release surgery were excluded, leaving 558 hands for the primary study group. Overall, the trend was for mean sensory latencies and prevalence of slowing to increase, the prevalence of symptoms to decrease, and the prevalence of CTS to remain unchanged. Among individual hands, nerve conduction abnormalities tended to persist (82% 11-year persistence), while symptoms fluctuated widely (13% 11-year persistence). There was a strong, direct linear correlation between initial severity of slowing and subsequent development of CTS; however, most workers who developed de novo slowing did not develop symptoms or CTS. We conclude that changes in conduction status of the median nerve occur naturally with increasing age and do not necessarily lead to symptoms and CTS.

The Rowing Cycle: Sources of Variance and Invariance in Ergometer and On-the-Water Performance.

In a recent study of the kinematics of the drive phase of the rowing stroke, Lamb (1989) provided detailed evidence that ergometer performance simulates on-the-water performance closely. In the present experiment, Lamb's analysis was extended in an investigation of the timing of the complete cycle of the rowing action of 5 rowers under each of those performance conditions. The authors followed Beek's (1992) suggestion that the first task in the analysis of timing in skilled movement is to specify the sources of variance and invariance in each particular task by identifying the major temporal constraints and the key relative timing variables. In addition, the possibility that some simple mathematical relationship (e.g., Schmidt, 1985) might describe the relative timing between the stroke and recovery phases of the rowing action when performed at different speeds was investigated. Both an absolute and a relative variability criterion were used in assessing and comparing timing variability over 4 speeds of rowing and between on-water and ergometer rowing in 5 elite male subjects. Criteria outlined by Gentner (1987) were used in assessing relative timing between stroke and recovery. The results indicated that variability decreases dramatically as a function of increased rowing rate; however, when variability is expressed as a function of movement duration, those decreases appear much less dramatic. Overall variability of the rowing cycle was caused principally by variability in the recovery phase, whereas the stroke phase was relatively invariant under both rowing conditions. The changes in the relative timing of the rowing stroke across the 4 speeds studied followed a simple mathematical rule, best described as linear increments in the stroke proportion of the total rowing cycle with increases in rowing rate. Moreover, those changes were similar across the 2 rowing conditions. The present results are discussed in light of findings from other forms of propulsion, such as walking, running, and stair climbing, in which the movement constraints are quite different.

Vitamin B6, vitamin C, and carpal tunnel syndrome. A cross-sectional study of 441 adults.

As part of an ongoing study of carpal tunnel syndrome (CTS) in industry, we measured plasma concentrations of pyridoxal 5'-phosphate (PLP, a measure of vitamin B6 status) and total ascorbate (ASC, a measure of vitamin C status) in 441 adult volunteers from six industries and a university exercise study. In the entire study group and in non-vitamin users (n = 218), there were no significant differences in mean plasma PLP or ASC concentrations between controls (neither symptoms nor slowing), subjects with symptoms only, subjects with median nerve slowing only, or subjects with CTS (symptoms + slowing). In male non-vitamin users (n = 137), there were significant inverse univariate associations between plasma PLP concentration and the prevalence of pain, the frequency of tingling and nocturnal awakening, and the Phalen test result. In this same subgroup, the ASC/PLP ratio was directly associated with the prevalence of pain and nocturnal awakening, and with the frequency of pain, tingling, and nocturnal awakening. In multivariate analyses, plasma ASC concentration predicted more median nerve slowing and confirmed CTS, and vitamin or vitamin interaction variables were independent predictors of 20 CTS-related outcomes. These multivariate relationships often occurred only after adjustment for age, gender, body mass index, serum alkaline phosphatase activity, or tobacco use. We conclude that there are significant relationships between plasma vitamin levels and both components of CTS (specific symptoms and median nerve slowing). The interaction between plasma PLP and ASC appears to be particularly important with respect to symptoms.

Fatal dog attacks, 1989-1994.

OBJECTIVES: To update data on fatal dog bites and see if past trends have continued. DESIGN: To merge data from vital records, the Humane Society of the United States, and searches of electronic news files. SETTING: United States. SUBJECTS: U.S. residents dying in the U.S. from 1989 through 1994 from dog bites. RESULTS: We identified 109 dog bite-related fatalities, of which 57% were less than 10 years of age. The death rate for neonates was two orders of magnitude higher than for adults and the rate for children one order of magnitude higher. Of classifiable deaths, 22% involved an unrestrained dog off the owner's property, 18% involved a restrained dog on the owner's property, and 59% involved an unrestrained dog on the owner's property. Eleven attacks involved a sleeping infant; 19 dogs involved in fatal attacks had a prior history of aggression; and 19 of 20 classifiable deaths involved an unneutered dog. Pit bulls, the most commonly reported breed, were involved in 24 deaths; the next most commonly reported breeds were rottweilers (16) and German shepherds (10). CONCLUSIONS: The dog bite problem should be reconceptualized as a largely preventable epidemic. Breed-specific approaches to the control of dog bites do not address the issue that many breeds are involved in the problem and that most of the factors contributing to dog bites are related to the level of responsibility exercised by dog owners. To prevent dog bite-related deaths and injuries, we recommend public education about responsible dog ownership and dog bite prevention, stronger animal control laws, better resources for enforcement of these laws, and better reporting of bites. Anticipatory guidance by pediatric health care providers should address dog bite prevention.

Tobacco, caffeine, alcohol, and carpal tunnel syndrome in American industry. A cross-sectional study of 1464 workers.

We investigated the effects of three legal drugs (tobacco, caffeine, and alcohol) on the prevalence of carpal tunnel syndrome (CTS) confirmed by nerve conduction studies (definite CTS) in two groups of American industrial workers: 656 nonclaimant workers and 808 working patients referred for upper extremity symptoms. Comparing workers with definite CTS to workers without definite CTS revealed 26% greater current use of tobacco, 19% greater lifetime use of tobacco, 5% greater current use of caffeine, 14% lesser current use of alcohol, and 75% greater history of alcohol abuse in the workers with definite CTS. All these differences were statistically significant. Those who currently used alcohol but not tobacco or caffeine were at the lowest risk for slowing, symptoms, and definite CTS. Those who currently used caffeine alone or in combination with tobacco were at the highest risk. In female workers, current smoking, current caffeine use, and current coffee consumption independently predicted 5.0% of the explainable risk for definite CTS. In male workers, history of alcohol abuse and current beer consumption independently predicted 3.0% of the explainable risk for definite CTS. Prevalence of slowing, symptoms, and definite CTS in 12 specific job categories correlated directly with current tobacco use. We conclude that the use of legal drugs affects the prevalence of median nerve slowing, symptoms, and carpal tunnel syndrome, but the effects of the drugs independently explain only a small portion of the total risk. Nevertheless, legal drug use or abuse may serve as a marker for increased CTS risk.

Amplitude Scaling Compensates for Serial Delays in Correcting Eye and Arm Movements.

Spatial and metrical parameters of the eye and arm movements made by human subjects (N = 7) in response to visual targets that were stepped unexpectedly either once (single step) or twice (double step) were studied. For the double-step, the displacement of a visual target was decreased or increased in amplitude at intervals before and during a movement. Provided the second target step occurred more than 100 ms before the onset of movement, the amplitude of the subjects' first response was altered in the direction of the new target location. But this amplitude scaling was not always sufficient to reach the new target location, and a second corrective response was required. The latency in producing this second response was greatly increased above reaction time latencies of movements to single-step targets, especially when the target change occurred 100 ms or more before movement onset. These findings suggest that even though serial processing limitations delay the production of a second corrective response, continuous parallel processing of visual information enables the amplitude of the first response to be altered with minimal delay. This enables some degree of real-time continuous control by the visuomotor control system.

Tryptophan metabolites, pyridoxine (vitamin B6) and their influence on the recurrence rate of superficial bladder cancer. Results of a prospective, randomised phase III study performed by the EORTC GU Group. EORTC Genito-Urinary Tract Cancer Cooperative Group.

This double-blind randomised phase III trial was designed to assess the effect of pyridoxine administration on the recurrence of Ta and T1 transitional cell tumours of the bladder. The trial accrued 291 patients and showed no significant difference between the pyridoxine and placebo treatment groups with respect to the time to first recurrence or the recurrence rate. Adjustment for the main prognostic factors, namely the recurrence rate prior to entry, the number of tumours at entry, the G grade and the levels of the tryptophan metabolites kynurenine plus acetyl kynurenine at entry do not change the overall conclusions.