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1.
Water Resour Res ; 57(1)2021.
Article in English | MEDLINE | ID: mdl-33746297

ABSTRACT

Identifying the spatial distribution and magnitude of seepage flux across the groundwater-surface water (GW-SW) interface is critical for assessing potential impairments and restoration alternatives for water bodies adjacent to sites with groundwater contamination. Measurement of the vertical distribution and time-varying characteristics of temperature in sediments provides an indirect way to map out spatial and temporal patterns of seepage flux into surface water. Two spreadsheet-based calculation tools are introduced that implement four one-dimensional analytical solutions to calculate the magnitude and direction of seepage flux based on measurement of steady-state vertical temperature profiles or transient diel temperature signals at two depths within sediment. Performance of these calculation tools is demonstrated for a pond receiving contaminated groundwater discharge from an adjacent landfill. Transient versus steady-state model performance is compared, and limitations of transient modelsare illustrated for a situation with unfavorable sediment characteristics and inadequate sensor spacing. The availability of a range of analytical solutions implemented within Microsoft Excel® is intended to encourage practitioners to explore use of this seepage flux characterization method and develop greater insight into best practices for model selection and use.

2.
Nature ; 459(7246): 540-2, 2009 May 28.
Article in English | MEDLINE | ID: mdl-19478778

ABSTRACT

Since the 1995 discovery of the broad iron K-line emission from the Seyfert galaxy MCG-6-30-15 (ref. 1), broad iron K lines have been found in emission from several other Seyfert galaxies, from accreting stellar-mass black holes and even from accreting neutron stars. The iron K line is prominent in the reflection spectrum created by the hard-X-ray continuum irradiating dense accreting matter. Relativistic distortion of the line makes it sensitive to the strong gravity and spin of the black hole. The accompanying iron L-line emission should be detectable when the iron abundance is high. Here we report the presence of both iron K and iron L emission in the spectrum of the narrow-line Seyfert 1 galaxy 1H 0707-495. The bright iron L emission has enabled us to detect a reverberation lag of about 30 s between the direct X-ray continuum and its reflection from matter falling into the black hole. The observed reverberation timescale is comparable to the light-crossing time of the innermost radii around a supermassive black hole. The combination of spectral and timing data on 1H 0707-495 provides strong evidence that we are witnessing emission from matter within a gravitational radius, or a fraction of a light minute, from the event horizon of a rapidly spinning, massive black hole.


Subject(s)
Extraterrestrial Environment/chemistry , Iron/analysis , Iron/chemistry
3.
Phys Rev Lett ; 96(1): 011302, 2006 Jan 13.
Article in English | MEDLINE | ID: mdl-16486434

ABSTRACT

We report new results from the Cryogenic Dark Matter Search (CDMS II) at the Soudan Underground Laboratory. Two towers, each consisting of six detectors, were operated for 74.5 live days, giving spectrum-weighted exposures of 34 (12) kg d for the Ge (Si) targets after cuts, averaged over recoil energies 10-100 keV for a weakly interacting massive particle (WIMP) mass of 60 GeV/c2. A blind analysis was conducted, incorporating improved techniques for rejecting surface events. No WIMP signal exceeding expected backgrounds was observed. When combined with our previous results from Soudan, the 90% C.L. upper limit on the spin-independent WIMP-nucleon cross section is 1.6 x 10(-43) cm2 from Ge and 3 x 10(-42) cm2 from Si, for a WIMP mass of 60 GeV/c2. The combined limit from Ge (Si) is a factor of 2.5 (10) lower than our previous results and constrains predictions of supersymmetric models.

4.
Crit Care Med ; 29(7): 1438-44, 2001 Jul.
Article in English | MEDLINE | ID: mdl-11445705

ABSTRACT

OBJECTIVES: To determine whether the simultaneous measurement of tissue pH, Pco2, and Po2 with a multiple-parameter fiberoptic sensor can be used to indicate the onset of hepatic dysoxia, to determine critical values, and to assess their use in predicting negative outcomes. DESIGN: Prospective animal study. SETTING: University research laboratory. SUBJECTS: Fourteen Yorkshire swine. INTERVENTIONS: Hemorrhagic shock (n = 11) was induced over 15 mins to lower systolic blood pressure to 40 mm Hg and was maintained for 30, 60, or 90 mins. Resuscitation was achieved with shed blood and warm saline to maintain mean pressure >60 mm Hg for 120 mins. Sham animals (n = 3) were subjected to 90 mins of sham shock, followed by a 120-min recovery period. MEASUREMENTS AND MAIN RESULTS: The multiple-parameter sensor continuously measured tissue pH, Pco2, and Po2. pH and Pco2, indicators of anaerobic metabolism, were plotted against tissue Po2. All shocked animals, but no sham animals, showed a biphasic relationship between Po2 and both pH and Pco2. Curves were fit to both an exponential and a dual-line linear function to determine critical values for Po2, pH, and Pco2. The length of time the animal was dysoxic was evaluated as a predictor of negative outcome. Critical values determined from the exponential models were more sensitive indicators of negative outcome than values determined from the linear model and more sensitive than arterial lactate and tonometric intramucosal pH and Pco2. CONCLUSIONS: The multiple-parameter sensor offers the unique opportunity to study solid as well as hollow organ dysoxia through the simultaneous measurement of interstitial pH, Pco2, and Po2 in a small tissue region. The gradual transition from sufficient oxygen availability to dysoxia as a result of hemorrhage was better described by an exponential equation. The length of time that pH was below or Pco2 was above the critical value determined from the exponential model was predictive of a negative outcome.


Subject(s)
Biosensing Techniques , Fiber Optic Technology , Liver Diseases/diagnosis , Oxygen/metabolism , Shock, Hemorrhagic/complications , Animals , Carbon Dioxide/metabolism , Cell Hypoxia , Extracellular Space/metabolism , Hemodynamics , Hydrogen-Ion Concentration , Linear Models , Liver Diseases/etiology , Liver Diseases/metabolism , Manometry , Models, Biological , Partial Pressure , Regional Blood Flow , Splanchnic Circulation , Swine
5.
Phys Rev Lett ; 84(25): 5699-703, 2000 Jun 19.
Article in English | MEDLINE | ID: mdl-10991035

ABSTRACT

The Cryogenic Dark Matter Search (CDMS) employs Ge and Si detectors to search for weakly interacting massive particles (WIMPs) via their elastic-scattering interactions with nuclei while discriminating against interactions of background particles. CDMS data, accounting for the neutron background, give limits on the spin-independent WIMP-nucleon elastic-scattering cross section that exclude unexplored parameter space above 10 GeV/c2 WIMP mass and, at >75% C.L., the entire 3sigma allowed region for the WIMP signal reported by the DAMA experiment.

6.
Obes Res ; 7(2): 141-9, 1999 Mar.
Article in English | MEDLINE | ID: mdl-10102250

ABSTRACT

OBJECTIVE: There are few data for associations of serum leptin with body fat, fat distribution, sex hormones, or fasting insulin in elderly adults. We hypothesized that the sex difference in serum leptin concentrations would disappear after adjustment for subcutaneous, but not visceral body fat. Serum leptin would not be associated with sex hormone concentrations or serum fasting insulin after adjusting for body fat and fat distribution. RESEARCH METHODS AND PROCEDURES: Subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) volumes were measured using magnetic resonance imaging in a cross-sectional sample of 56 nondiabetic, elderly men and women aged 64 years to 94 years. Serum leptin, sex hormones (testosterone and estrone), sex hormone-binding globulin, and fasting insulin were also measured. Nine women were taking hormone replacement, and five men were clinically hypogonadal. RESULTS: Leptin was significantly associated with both SAT and VAT in each sex. Adjustment for SAT reduced the sex difference in leptin by 56%, but adjustment for VAT increased the difference by 25%. Leptin was not associated with serum estrone or hormone replacement therapy in the women, but had a significant, negative association with testosterone in the men that was independent of SAT, but not VAT. Leptin was significantly associated with fasting insulin in both sexes independent of age, sex hormones, sex hormone-binding globulin, VAT and SAT. DISCUSSION: Sex difference in serum leptin is partly explained by different amounts of SAT. Studies including both men and women should adjust for SAT rather than total body fat that includes VAT. The sex difference in serum leptin is not due to estrogen, but may be partly explained by testosterone. Testosterone is negatively associated with leptin in men, but the association is confounded with VAT. Leptin is associated with fasting insulin in nondiabetic elderly men and women independent of body fat, fat distribution, or sex hormones.


Subject(s)
Adipose Tissue , Body Composition , Gonadal Steroid Hormones/blood , Insulin/blood , Proteins/analysis , Aged , Aged, 80 and over , Blood Glucose/analysis , Body Constitution , Body Mass Index , Cohort Studies , Estrogen Replacement Therapy , Estrone/blood , Female , Humans , Leptin , Longitudinal Studies , Male , Middle Aged , Testosterone/blood
7.
Am J Epidemiol ; 147(8): 755-63, 1998 Apr 15.
Article in English | MEDLINE | ID: mdl-9554417

ABSTRACT

Muscle mass decreases with age, leading to "sarcopenia," or low relative muscle mass, in elderly people. Sarcopenia is believed to be associated with metabolic, physiologic, and functional impairments and disability. Methods of estimating the prevalence of sarcopenia and its associated risks in elderly populations are lacking. Data from a population-based survey of 883 elderly Hispanic and non-Hispanic white men and women living in New Mexico (the New Mexico Elder Health Survey, 1993-1995) were analyzed to develop a method for estimating the prevalence of sarcopenia. An anthropometric equation for predicting appendicular skeletal muscle mass was developed from a random subsample (n = 199) of participants and was extended to the total sample. Sarcopenia was defined as appendicular skeletal muscle mass (kg)/height2 (m2) being less than two standard deviations below the mean of a young reference group. Prevalences increased from 13-24% in persons under 70 years of age to >50% in persons over 80 years of age, and were slightly greater in Hispanics than in non-Hispanic whites. Sarcopenia was significantly associated with self-reported physical disability in both men and women, independent of ethnicity, age, morbidity, obesity, income, and health behaviors. This study provides some of the first estimates of the extent of the public health problem posed by sarcopenia.


Subject(s)
Muscular Atrophy/epidemiology , Adult , Aged , Aged, 80 and over , Aging/physiology , Anthropometry , Body Composition , Body Mass Index , Cross-Sectional Studies , Female , Frail Elderly , Geriatric Assessment , Hispanic or Latino , Humans , Logistic Models , Male , New Mexico/epidemiology , Prevalence , Random Allocation , White People
8.
Physician Assist ; 19(6): 73-6, 78, 1995 Jun.
Article in English | MEDLINE | ID: mdl-10143795

ABSTRACT

Assisted suicide continues to be a topic of debate among health care providers, including PAs. The Public Policy Committee of the Michigan Academy of Physician Assistants surveyed all licensed PAs in Michigan regarding assisted suicide in an effort to determine whether a public policy statement should be developed, and whether that could be extrapolated into a resolution to be taken to the House of Delegates (HOD) of the American Academy of Physician Assistants in 1994. Based on the divergent results of the survey, the Michigan delegation did not submit a resolution to the HOD.


Subject(s)
Attitude of Health Personnel , Physician Assistants/psychology , Public Policy , Suicide, Assisted/statistics & numerical data , Euthanasia/statistics & numerical data , Humans , Michigan , Physician Assistants/statistics & numerical data , Societies, Medical , Surveys and Questionnaires
9.
Pediatrics ; 85(2): 139-43, 1990 Feb.
Article in English | MEDLINE | ID: mdl-2296500

ABSTRACT

The pediatric literature has documented a growing attention to defining the nature and quality of residency training. The critical incident technique, a method widely accepted in industrial settings, was used in this study to determine attitudes and behaviors deemed critical for successful performance of residents in a pediatric training program. Structured interviews with 17 senior teaching faculty produced descriptions of resident behavior that were classified into the following mutually exclusive categories: commitment to learning, clinical judgment, communicating medical information, recognition of limits, professional behavior, interpersonal skills with patients, and dealing with emergency situations. Only 30% of the critical incidents obtained from the faculty were related to criteria traditionally used to select and evaluate residents, such as knowledge and technical skills, while the remaining incidents were noncognitive in nature. The results of this study have implications for the evaluation and selection of residents and suggest that pediatric program directors and faculty must give attention to the means by which noncognitive skills are fostered in residents.


Subject(s)
Attitude of Health Personnel , Clinical Competence , Internship and Residency/standards , Pediatrics/education , Behavior , Communication , Educational Measurement , Evaluation Studies as Topic , Hospital Bed Capacity, 500 and over , Humans , Iowa , Judgment
10.
Radiology ; 172(1): 275-6, 1989 Jul.
Article in English | MEDLINE | ID: mdl-2740514

ABSTRACT

Open-ended interviews with 107 patients documented specific patient expectations of radiologic procedures during which there was no direct radiologist-patient interaction. Patient expectations could be classified into those related to the facility and those related to interactions with radiology staff. Among facility-related expectations, waiting time far outweighed all other concerns. Interpersonal skills were the predominant expectation of radiology staff. The role of the radiologist in fulfilling patient expectations was less clear. Only 10% of unprompted patients cited the radiologist as a factor in their expectations. When patients were specifically prompted to discuss the radiologist's role, communication skills, accuracy of interpretation, and interpersonal skills were the predominant concerns.


Subject(s)
Attitude , Patients/psychology , Radiology , Consumer Behavior , Humans , Physician-Patient Relations , Professional-Patient Relations
11.
J Cell Biol ; 103(3): 1129-33, 1986 Sep.
Article in English | MEDLINE | ID: mdl-3745265

ABSTRACT

Cultured endothelial cells secrete a platelet-derived growth factor-like molecule (PDGFc). We examined the effects of purified human alpha-thrombin on the production of PDGFc in cultures of human umbilical vein endothelial cells (HUVE) using a specific radioreceptor assay for PDGF. Addition of physiologically relevant concentrations of alpha-thrombin (0.1 to 10 U/ml) induced a time- and dose-dependent increase in the release of PDGFc into the culture medium. Significant stimulation of PDGFc release was observed as early as 1.5 h after addition of alpha-thrombin (10 U/ml) with a 4.9 +/- 1.1 fold increase at 24 h (mean +/- SEM of nine experiments, P less than 0.01). alpha-Thrombin treatment of HUVE did not affect cell viability as assessed by trypan blue dye exclusion. The receptor binding of PDGFc secreted by HUVE in response to alpha-thrombin was inhibited by monospecific antibody to purified human PDGF indicating that the molecule(s) is closely related to PDGF. alpha-Thrombin inactivated with diisopropylfluorophosphate was without stimulatory effect. Lysis of HUVE by repeated cycles of freeze/thaw released minimal PDGFc (less than 0.3 ng per 10(6) cells) compared to levels of PDGFc released into supernatant medium in response to alpha-thrombin (greater than 5.0 ng per 10(6) cells after a 24-h incubation with 10 U/ml alpha-thrombin). Moreover, incubation of freeze/thaw lysates of HUVE with alpha-thrombin failed to release PDGFc. Over a 3-h time course, however, alpha-thrombin-induced secretion of PDGFc was not prevented by cycloheximide. We conclude that alpha-thrombin induces secretion of PDGFc from HUVE by a nonlytic mechanism requiring the serine esterase activity of the enzyme. Although this effect does not initially require de novo protein synthesis, it does require cell-mediated conversion of PDGFc from an inactive to an active form.


Subject(s)
Endothelium/metabolism , Platelet-Derived Growth Factor/metabolism , Thrombin/pharmacology , Cells, Cultured , Cycloheximide/pharmacology , Dose-Response Relationship, Drug , Endothelium/drug effects , Humans , Umbilical Veins
12.
J Oral Maxillofac Surg ; 44(5): 353-60, 1986 May.
Article in English | MEDLINE | ID: mdl-3009757

ABSTRACT

The use of hydroxylapatite mixed with autogenous bone to augment the area posterior to the mental foramen is described. This method is combined with an interposed bone graft technique in the symphyseal area. The clinical implications are discussed in relation to potential nerve damage, height to be gained, and effects on lip-chin profile, and the results in 29 patients are reported.


Subject(s)
Alveolar Ridge Augmentation/methods , Bone Transplantation , Hydroxyapatites , Mandible/surgery , Oral Surgical Procedures, Preprosthetic/methods , Prostheses and Implants , Adult , Aged , Atrophy , Cephalometry , Durapatite , Esthetics, Dental , Female , Humans , Jaw, Edentulous/surgery , Male , Mandible/anatomy & histology , Mandible/pathology , Middle Aged , Osteotomy/methods
17.
Science ; 167(3918): 701-3, 1970 Jan 30.
Article in English | MEDLINE | ID: mdl-17781553

ABSTRACT

An electromagnetic search for magnetic monopoles of the minimum size predicted by Dirac, or of any larger magnitude, has been performed on 8.37 kilograms of lunar surface material. No monopole was found. This experimnent sets new limists on the production cross section for monopoles and on their occurrence in cosmic radiation.

19.
Southwest Med ; 50(12): 234-8, 1969 Dec.
Article in English | MEDLINE | ID: mdl-5368001
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