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Biomedical subjects

K Kelleher

Publications and source records attributed to K Kelleher.

At least 19 recordsLinked to original sources
PubMed2007

The lakes of Titan.

The surface of Saturn's haze-shrouded moon Titan has long been proposed to have oceans or lakes, on the basis of the stability of liquid methane at the surface. Initial visible and radar imaging failed to find any evidence of an ocean, although abundant evidence was found that flowing liquids have existed on the surface. Here we provide definitive evidence for the presence of lakes on the surface of Titan, obtained during the Cassini Radar flyby of Titan on 22 July 2006 (T16). The radar imaging polewards of 70 degrees north shows more than 75 circular to irregular radar-dark patches, in a region where liquid methane and ethane are expected to be abundant and stable on the surface. The radar-dark patches are interpreted as lakes on the basis of their very low radar reflectivity and morphological similarities to lakes, including associated channels and location in topographic depressions. Some of the lakes do not completely fill the depressions in which they lie, and apparently dry depressions are present. We interpret this to indicate that lakes are present in a number of states, including partly dry and liquid-filled. These northern-hemisphere lakes constitute the strongest evidence yet that a condensable-liquid hydrological cycle is active in Titan's surface and atmosphere, in which the lakes are filled through rainfall and/or intersection with the subsurface 'liquid methane' table.

Journal Article↗
PubMed2006

Titan Radar Mapper observations from Cassini's T3 fly-by.

Cassini's Titan Radar Mapper imaged the surface of Saturn's moon Titan on its February 2005 fly-by (denoted T3), collecting high-resolution synthetic-aperture radar and larger-scale radiometry and scatterometry data. These data provide the first definitive identification of impact craters on the surface of Titan, networks of fluvial channels and surficial dark streaks that may be longitudinal dunes. Here we describe this great diversity of landforms. We conclude that much of the surface thus far imaged by radar of the haze-shrouded Titan is very young, with persistent geologic activity.

Journal Article↗
PubMed2006

The sand seas of Titan: Cassini RADAR observations of longitudinal dunes.

The most recent Cassini RADAR images of Titan show widespread regions (up to 1500 kilometers by 200 kilometers) of near-parallel radar-dark linear features that appear to be seas of longitudinal dunes similar to those seen in the Namib desert on Earth. The Ku-band (2.17-centimeter wavelength) images show approximately 100-meter ridges consistent with duneforms and reveal flow interactions with underlying hills. The distribution and orientation of the dunes support a model of fluctuating surface winds of approximately 0.5 meter per second resulting from the combination of an eastward flow with a variable tidal wind. The existence of dunes also requires geological processes that create sand-sized (100- to 300-micrometer) particulates and a lack of persistent equatorial surface liquids to act as sand traps.

Extraterrestrial Environment↗
PubMed2005

Cassini radar views the surface of Titan.

The Cassini Titan Radar Mapper imaged about 1% of Titan's surface at a resolution of approximately 0.5 kilometer, and larger areas of the globe in lower resolution modes. The images reveal a complex surface, with areas of low relief and a variety of geologic features suggestive of dome-like volcanic constructs, flows, and sinuous channels. The surface appears to be young, with few impact craters. Scattering and dielectric properties are consistent with porous ice or organics. Dark patches in the radar images show high brightness temperatures and high emissivity and are consistent with frozen hydrocarbons.

Atmosphere↗
PubMed2005

Psychological symptoms and nonfatal unintentional injuries among Chinese adolescents: a prospective study.

PURPOSE: To describe patterns of nonfatal unintentional injuries and investigate the association of psychological symptoms with injury risk among adolescents in Guangxi, China. METHODS: Adolescents were selected from middle and high school students in Baise City, Guangxi, China. Psychological symptoms at baseline were measured using SCL-90-R and nonfatal unintentional injuries that occurred among participants were recorded using a standardized injury surveillance questionnaire. Annual injury rates per 100 adolescents by adolescents' demographic and family characteristics were calculated. Student's t-test and the Chi-square test were used to test differences in mean raw scores of SCL-90-R subscales and injury rates. Relative risks and odds ratios of injury with 95% confidence intervals were calculated in univariate analyses and multivariate logistic models. RESULTS: A total of 1474 middle and high school students finished the study. Of them, 442 reported nonfatal unintentional injuries during the study period, resulting in an annual injury rate of 30.3 per 100 adolescents. Boys had a significantly higher injury rate than girls (32.6% vs. 27.4%). Injury rate decreased as the adolescents' age increased. Compared with adolescents who were not injured, the injured adolescents had higher average raw scores of all subscales of SCL-90-R, with an exception of the subscale for hostility. All SCL-90-R subscales factors, except those for hostility and phobia, were associated with injury risk. After confounding effects of age, gender, and ethnicity were controlled using logistic regression models, SCL-90-R subscales for somatization (OR = 2.00, 95% CI 1.52-2.63), obsessive-compulsiveness (OR = 2.10, 95% CI 1.71-2.58), interpersonal-sensitivity (OR = 1.66, 95% CI 1.34-2.06), depression (OR = 2.00, 95% CI 1.59-2.51), anxiety (OR = 2.08, 95% CI 1.62-2.66), and psychoticism (OR = 1.60, 95% CI 1.26-2.03) were significantly associated with an elevated injury risk. CONCLUSION: Psychological symptoms are associated with an elevated risk of nonfatal unintentional injury among middle and high school students. Mental health services, such as psychological counseling, may help reduce the risk of nonfatal unintentional injuries among Chinese adolescents.

Accidents↗
PubMed2005

The incidence of S. aureus bacteraemia in acute hospitals of the Mid-Western Area, Ireland, 2002-2004.

Concerns about healthcare-associated infections and the global crisis in antimicrobial resistance has combined to accentuate the fears around so-called "superbugs". In Ireland there is no single agreed indicator regarded as a true measure of the level of methicillin resistant Staphylococcus aureus (MRSA) in hospitals. The objective of this study was to compare two crude measures of MRSA--the percentage of bacteraemia caused by MRSA and the incidence rate (per 1000 bed days used) of MRSA bacteraemia in six acute hospitals. We examined all blood cultures positive for S. aureus (methicillin sensitive and resistant) from 2002 to 2004 in the Health Service Executive (HSE) Mid-Western Area of Ireland. Hospital In-Patient Enquiry (HIPE) data was used to determine monthly in-patient bed days used. Of 245 patient episodes of bacteraemia, 119 were MRSA. The trends in the percentage of isolates that were MRSA and the incidence rate calculated were compared. The incidence rate appears to be a more reliable and robust indicator of MRSA in hospitals than the percentage. Despite many difficulties in interpreting indicators of MRSA they should not preclude the regular publication of data at least at regional level in Ireland.

Acute Disease↗
PubMed2005

Human brucellosis in the Mid-West 2002-3.

Human brucellosis remains a serious public health issue in Ireland. Clinical notifications in the Mid-Western Area (HSE-MWA) underestimate the burden of illness and attendant morbidity in the region. The diagnosis of acute and chronic human brucellosis depends on the clinical evidence and the results from laboratory serological testing or culture on rare occasion. This study examined the clinical evidence behind locally defined serological "positives" in the HSE-MWA from 2002 to 2003. Ninety cases were detected in 2002 and 31 in 2003. While sampling bias is likely to be present, aspects of brucellosis in Ireland were confirmed. Middle-aged males were most commonly affected. The majority of cases were linked to farming or veterinary practice. Symptoms such as sweats, fever and weight loss were commonly associated with acute brucellosis infection while malaise was common in acute and chronic brucellosis. A clear definition of what is notifiable is needed. Surveillance systems must appreciate the importance of both clinical and laboratory evidence to classify confirmed or probable brucellosis as paired sera were not common. Public health authorities must follow-up the clinical aspects for accurate national statistics. General practitioners in the Mid-West appear to be vigilant regarding brucellosis in their patients. Regional zoonoses committees are useful in monitoring disease prevalence in human and animal populations without compromising confidentiality.

Adolescent↗
PubMed2003

The use of primary/national school absenteeism as a proxy retrospective child health status measure in an environmental pollution investigation.

As a result of community concerns over animal and human ill health centred around a rural town in the Republic of Ireland, a series of epidemiological studies were conducted. The absence of adequate health-information systems forced researchers to investigate alternative methods of assessing child health in the 'at-risk' area. This study aimed to examine annual primary/national school attendance data over a 10 year period as a proxy health status measure. Data from six geographical areas were analysed; one of these six areas was designated the 'high-risk' area on the basis of reports of animal ill health. Significantly higher absenteeism rates were noted in the 'high-risk' area in nine of the 10 years examined. Although caution is urged in the interpretation of these results, this study demonstrates that primary/national school absenteeism data can act as a useful, albeit crude, proxy measure of health status.

Absenteeism↗
PubMed2003

Dead cattle, lead and child health.

This study was carried out as part of a larger interagency investigation in response to concerns about human health following the death of three cattle from lead poisoning in an old lead mining area in Silvermines, Tipperary. Its aim was to screen for lead toxicity in the local child population. Screening consisted of measurement of blood lead concentrations and the completion of questionnaires regarding exposure to lead and general health. Pre-school and primary school children resident in four surrounding district electoral divisions (DEDs) were specifically targeted. One out of 334 (0.3%) children screened had an elevated blood lead concentration. The geometric mean lead concentration was 2.6 microg/dl which is below the intervention lead concentration of 10 microg/dl recommended by the CDC. The mean lead concentration in those aged under three years was statistically significantly higher than in those aged three years and over (3.4 microg/dl vs 2.5 microg/dl; p=0.000581). No specific health problems were identified by the questionnaires. This study concluded that the elevated environmental lead levels which were demonstrated by other agencies involved in this investigation are not currently being transferred to children. It recommends further blood screening of children in the area and ongoing education to minimise the risk of lead toxicity in the area in the future.

Adolescent↗
PubMed2002

Functional limitations of school-aged children seen in primary care.

OBJECTIVE: The purpose of the present study was to assess the prevalence of functional limitations in children seen in a large paediatric practice network and to identify sociodemographic, family and psychosocial factors related to functional limitations. STUDY DESIGN: Cross-sectional analysis. POPULATION: Children were recruited from two large, practice-based primary care research networks during their paediatric office visits. For the present study, participants included 14 630 school-aged children (ages 6-15 years) and their caregivers. OUTCOMES MEASURED: Parents completed written questionnaires including the Pediatric Symptom Checklist, the Family Apgar and the Functional Limitations Index. RESULTS: Findings indicated that 15% of children surveyed had some limitation in their daily functioning. More children had schoolwork and physical function limitations than limitations in personal and self-care. Logistic regression equations predicted functional limitations and health status in children from a model of sociodemographic factors, psychosocial symptoms and family functioning. CONCLUSIONS: A low but significant number of school-age children seen in the primary care setting experience functional limitations. Children with any psychosocial symptoms were at increased risk for functional limitations, indicating the critical need to screen for functional impairment in children with suspected behavioural or emotional problems. A screening tool of functional limitations may be useful for assessing the presence or absence of such limitations in children's daily function and warrants further investigation.

Activities of Daily Living↗
PubMed2001

Monitoring and enforcing cultural competence in Medicaid managed behavioral health care.

In recent years cultural competence has expanded beyond language provisions to include understanding and factoring into services provision the cultural perspectives clients may have that are different from the majority culture. The federal government requires state Medicaid programs to offer culturally competent services, but little is known about how states implement such mandates and monitor and enforce them. We reviewed the origins and implications of cultural competence mandates and conducted a brief case study of 5 states to learn about the implementation of cultural competence provisions in behavioral managed care contracts. We found that states and managed behavioral health organizations (MBHOs) vary in their definitions and implementation of standards to ensure mental health care access for vulnerable populations. Although states had a variety of oversight mechanisms, varying contractual requirements ranging from optional to required, vague contract language, no existing standardized indicators or definitions, and scant data on the cultural characteristics of the populations enrolled in Medicaid managed care hamper monitoring and enforcement of cultural competence by states. Implications for MBHOs, states, and the federal government, as well as services researchers, follow.

Clinical Competence↗
PubMed2001

Physician gender and psychosocial care for children: attitudes, practice characteristics, identification, and treatment.

OBJECTIVE: To examine differences by physician gender in the identification and treatment of childhood psychosocial problems. DESIGN: Survey of patients (n = 19,963) and physicians (n = 366) in primary care offices in 2 large, practice-based research networks. Multivariate regressions were used to control for patient, physician, and visit characteristics, with a correction for the clustered sample. SUBJECTS: Children ages 4 to 15 years seen consecutively for nonemergent care. MEASURES: Physician report of attitudes, training, practice factors, and identification and treatment of psychosocial problems. Parental report of demographics and behavioral symptoms. RESULTS: Compared with male physicians, female physicians were less likely to view care for psychosocial problems as burdensome. They were more likely to see children who were female, younger, black or Hispanic, in single-parent households, enrolled in public or managed health plans, and with physical health limitations. Children seen by male physicians had higher symptom counts. Male physicians were more likely to report having primary care responsibility for their patient and that parents agree with their care plan. Female physicians spent more time with patients. After controlling for these differences, female physicians did not differ from male physicians in identification or treatment of childhood psychosocial problems. CONCLUSIONS: Male and female physicians see different kinds of children for different visit purposes and have different kinds of relationships with their patients. After controlling for these factors, management of childhood psychosocial problems does not differ by physician gender. Improving management of psychosocial conditions depends on identifying modifiable factors that affect diagnosis and treatment; our work suggests that characteristics of the practice environment, physician-patient relationship, and patient self-selection deserve more research.

Adolescent↗