Search

Focuses on the formulation of the second order Dehn functions. Geometric calculus of spherical pictures; Infinite variety of subquadratic behavior; Investigation on the functions of HNN-extensions.

Self-interest vs. cooperation is a fundamental dilemma in animal behavior as well as in human and organizational behavior. In organizations, how to get people to cooperate despite or in conjunction with their self-interest is fundamental to the achievement of a common goal. While both organizational designs and social interactions have been found to further cooperation in organizations, some of the literature has received contradictory support, just as very little research, if any, has examined their joint effects in distributed organizations, where communication is usually achieved via different communication media. This paper reviews the extant literature and offers a set of hypotheses to integrate current theories and explanations. Further, it discusses how future research should examine the joint effects of media, incentives, and social interactions.

Purpose: To investigate the utility of hyperpolarized He-3 MRI for detecting regional lung ventilated volume (VV) changes in response to exercise challenge and leukotriene inhibitor montelukast, human subjects with exercise induced bronchoconstriction (EIB) were recruited. This condition is described by airway constriction following exercise leading to reduced forced expiratory volume in 1 second (FEV1) coinciding with ventilation defects on hyperpolarized He-3 MRI., Materials and Methods: Thirteen EIB subjects underwent spirometry and He-3 MRI at baseline, postexercise, and postrecovery at multiple visits. On one visit montelukast was given and on two visits placebo was given. Regional VV was calculated in the apical/basilar dimension, in the anterior/posterior dimension, and for the entire lung volume. The whole lung VV was used as an end-point and compared with spirometry., Results: Postchallenge FEV1 dropped with placebo but not with treatment, while postchallenge VV dropped more with placebo than treatment. Sources of variability for VV included region (anterior/posterior), scan, and treatment. VV correlated with FEV1/ forced vital capacity (FVC) and forced expiratory flow between 25 and 75% of FVC and showed gravitational dependence after exercise challenge., Conclusion: A paradigm testing the response of ventilation to montelukast revealed both a whole-lung and regional response to exercise challenge and therapy in EIB subjects., (Copyright © 2013 Wiley Periodicals, Inc.)

Phytoplankton species vary in their physiological properties, and are expected to respond differently to seasonal changes in water column conditions. To assess these varying distribution patterns, we used 412 samples collected monthly over 12 years (1991-2004) at the Bermuda Atlantic Time-Series Study site, located in the northwestern Sargasso Sea. We measured plastid 16S ribosomal RNA gene abundances with a terminal restriction fragment length polymorphism approach and identified distribution patterns for members of the Prymnesiophyceae, Pelagophyceae, Chrysophyceae, Cryptophyceae, Bacillariophyceae and Prasinophyceae. The analysis revealed dynamic bloom patterns by these phytoplankton taxa that begin early in the year, when the mixed layer is deep. Previously, unreported open-ocean prasinophyte blooms dominated the plastid gene signal during convective mixing events. Quantitative PCR confirmed the blooms and transitions of Bathycoccus, Micromonas and Ostreococcus populations. In contrast, taxa belonging to the pelagophytes and chrysophytes, as well as cryptophytes, reached annual peaks during mixed layer shoaling, while Bacillariophyceae (diatoms) were observed only episodically in the 12-year record. Prymnesiophytes dominated the integrated plastid gene signal. They were abundant throughout the water column before mixing events, but persisted in the deep chlorophyll maximum during stratified conditions. Various models have been used to describe mechanisms that drive vernal phytoplankton blooms in temperate seas. The range of taxon-specific bloom patterns observed here indicates that different 'spring bloom' models can aptly describe the behavior of different phytoplankton taxa at a single geographical location. These findings provide insight into the subdivision of niche space by phytoplankton and may lead to improved predictions of phytoplankton responses to changes in ocean conditions.

Atomic force microscopy (AFM) performed with variable-force imaging was recently demonstrated to be an accurate method of determining the diameter and number of sidewalls of a carbon nanotube (CNT). This AFM technique provides an alternative to transmission electron microscopy (TEM) when TEM imaging is not possible due to substrate thickness. We have used variable-force AFM to characterize horizontally aligned CNTs grown on ST-cut quartz. Our measurements reveal new aspects of horizontally aligned growth that are essential for enhancing the performance of CNT-based devices as well as understanding the growth mechanism. First, previously reported optimal growth conditions produce a large spread in CNT diameters and a significant fraction of double-walled CNTs. Second, monodispersity is significantly improved when growth temperature is reduced. Third, CNTs with diameters up to 5 nm align to the substrate, suggesting the interaction between CNTs and the quartz lattice is more robust than previously reported.

Background: Factors affecting fractional exhaled nitric oxide (FeNO) in early childhood are incompletely understood., Objective: To examine the relationships between FeNO and allergic sensitization, total IgE, atopic dermatitis, rhinitis, asthma, and lung function (spirometry) in children., Methods: Children at high risk of asthma and other allergic diseases because of parental history were enrolled at birth and followed prospectively. FeNO was measured by an online technique at ages 6 and 8 years. Relationships among FeNO, various atopic characteristics, and asthma were evaluated., Results: Reproducible FeNO measurements were obtained in 64% (135/210) of 6-year-old and 93% (180/194) of 8-year-old children. There was seasonal variability in FeNO. Children with aeroallergen sensitization at ages 6 and 8 years had increased levels of FeNO compared with those not sensitized (geometric mean; 6 years, 10.9 vs 6.7 parts per billion [ppb], P < .0001; 8 years, 14.6 vs 7.1 ppb, P < .0001). FeNO was higher in children with asthma than in those without asthma at 8 years but not 6 years of age (6 years, 9.2 vs 8.3 ppb, P = .48; 8 years, 11.5 vs 9.2 ppb, P = .03). At 8 years of age, this difference was no longer significant in a multivariate model that included aeroallergen sensitization (P = .33). There were no correlations between FeNO and spirometric indices at 6 or 8 years of age., Conclusion: These findings underscore the importance of evaluating allergen sensitization status when FeNO is used as a potential biomarker in the diagnosis and/or monitoring of atopic diseases, particularly asthma.

Vertical, seasonal and geographical patterns in ocean microbial communities have been observed in many studies, but the resolution of community dynamics has been limited by the scope of data sets, which are seldom up to the task of illuminating the highly structured and rhythmic patterns of change found in ocean ecosystems. We studied vertical and temporal patterns in the microbial community composition in a set of 412 samples collected from the upper 300 m of the water column in the northwestern Sargasso Sea, on cruises between 1991 and 2004. The region sampled spans the extent of deep winter mixing and the transition between the euphotic and the upper mesopelagic zones, where most carbon fixation and reoxidation occurs. A bioinformatic pipeline was developed to de-noise, normalize and align terminal restriction fragment length polymorphism (T-RFLP) data from three restriction enzymes and link T-RFLP peaks to microbial clades. Non-metric multidimensional scaling statistics resolved three microbial communities with distinctive composition during seasonal stratification: a surface community in the region of lowest nutrients, a deep chlorophyll maximum community and an upper mesopelagic community. A fourth microbial community was associated with annual spring blooms of eukaryotic phytoplankton that occur in the northwestern Sargasso Sea as a consequence of winter convective mixing that entrains nutrients to the surface. Many bacterial clades bloomed in seasonal patterns that shifted with the progression of stratification. These richly detailed patterns of community change suggest that highly specialized adaptations and interactions govern the success of microbial populations in the oligotrophic ocean.

Objective: To report a case of severe memory loss in an elderly patient after initiation of fluoxetine., Case Summary: An 87-year-old white woman was started on fluoxetine for depression, and the dose was titrated to 20 mg/d. She developed progressive memory loss over the next 6 weeks for which she ultimately was hospitalized. Other potential causes for her memory loss were ruled out. After fluoxetine was discontinued, the patient's memory improved significantly over the next 2 months. An objective causality assessment indicated a possible relationship between the memory loss and fluoxetine in this patient., Discussion: Our report documents a case of severe reversible memory deterioration after initiating fluoxetine. Fluoxetine has a favorable adverse effect profile when compared with older classes of antidepressants. Postmarketing studies and isolated case reports, however, suggest that fluoxetine may harm memory in some patients. Some selective serotonin-reuptake inhibitors (SSRIs) appear to cause memory loss more frequently than others., Conclusions: Clinicians should be aware of the possible effects of fluoxetine (and possibly other SSRIs) on memory.

A feedforward neural net with d input neurons and with a single hidden layer of n neurons is given byg(x(1), em leader,x(d))= summation operator j=1na(j)sigma,where a(j), theta(j), w(ji) in R. In this paper we study the approximation of arbitrary functions F:R(d)-->R by a neural net in an L(p)(&mgr;) norm for some finite measure &mgr; on R(d). We prove that under natural moment conditions, a neural net with non-polynomial function can approximate any given function.

An ambient particle monitoring study was conducted in Washington, D.C. during the summer of 1994 as part of the Metropolitan Acid Aerosol Characterization Study (MAACS). Acid aerosol and inhalable (particulate matter with aerodynamic diameters < 10 micron; PM10) and fine (particulate matter with aerodynamic diameters < 2.5 micron; PM2.5) particle samples were collected for 24-hr periods (9 A.M.-9 A.M. EDT) on alternate days at six monitoring sites located throughout the greater Washington, D.C. area. Monitoring sites were located in both urban and rural areas and were generally situated along a southwest to northeast line due to the prevailing winds. Information on site characteristics, including population density and distance from the city center, was also obtained, as were data on meteorological parameters. Results from this study show strong correlations among the particulate measures, PM10, PM2.5, SO4(2-), and H+. These strong correlations resulted from the fact that PM2.5 comprised 77% of PM10, with SO4(2-)-related species accounting for 49% of total PM2.5. PM10, PM2.5, SO4(2-), and H+ concentrations were found to be uniform across the metropolitan Washington area. Spatial variation was found, however, for coarse particles (PM2.5-10) and NH3 concentrations. In our previous Philadelphia study, population density was an important determinant of spatial variation in coarse particles and NH3 concentrations, however, in Washington, D.C., population density was not associated with observed spatial patterns in coarse particle concentrations, but was an important determinant of NH3 concentrations. When data from one site (Reservoir) was excluded from the analysis, population density explained larger percentage of the variability in NH3 levels and became an important determinant of the H+/SO4(2-) ratio as well. Ambient H+ models developed from Philadelphia data were found to predict H+ concentrations in Washington, D.C. reasonably well, representing an improvement over measurements made at a single stationary ambient monitoring site.

In more than 15 years of functioning as a medical director, addressing the needs and wants of patients, physicians, hospitals, and ancillary health care suppliers, I have accumulated pieces of ¿wisdom¿ that I now feel I should share with others in medical management. The concepts are fairly simple, but they are of significant value in the ¿real-life¿ management of people. The seven simple ideas outlined in this article are not meant to be the end-all to management philosophy. Books have been written about each idea, and there are hundreds of good ideas in many sources I do not touch on here. However, I have found these seven items of significant value in dealing with others and hope others find them similarly useful.

A literature survey was used to identify pre-operative risks that commonly result in unwanted post-operative complications in the elderly. By adapting these risk conditions into a pre-operative survey, seniors who might have these complications were identified. Practitioners were notified of these risk factors. Elective surgery was postponed, when necessary, to have patients stop smoking and to gain training in pulmonary toilet. When in the inpatient setting, the patients were followed by both the surgeon and the appropriate specialist to reduce complications rates. By developing and employing this approach, a 25 percent decrease in unwanted complications was experienced, mostly due to reduction in pulmonary events. This resulted in an associated 58 percent drop in unwanted length-of-stay days in the hospital per 1,000 senior patients. Outcomes were improved, while inpatient utilization was reduced.

This paper presents the development and evaluation of an ambient particle concentrator for conducting animal inhalation exposure studies. The system utilizes the principle of virtual impactors to concentrate ambient particles in the size range 0.1-2.5 microns (aerodynamic diameter; dp) by drawing them through a series of three virtual impactors. Each impactor contains the majority of ambient fine mass (dp < 2.5 microns aerodynamic diameter) in a bleed flow (minor flow) that is 20% of the total flow entering the virtual impactor. The virtual impactors have been characterized using indoor air samples as test aerosols. Fine mass and sulfate concentrations at the outlet of the concentrating system were compared to the ambient fine mass and sulfate levels, which were determined using Harvard-Marple impactors. In each of the stages, particle concentration was increased by a factor of approximately 3. Thus, an overall concentration factor of about 25-30 was achieved. The main goal of this study was to demonstrate the feasibility of conducting animal exposures using the newly developed ambient fine particle concentrator.

Want to motivate others? Establish meaningfulness and value to them of what they are supposed to do for you, and provide the tools they need to do it. Until they see the value to them, and that value outweighs their perceived risks or costs of doing it, you may get motion but you won't get motivated behaviors. Without motivated behaviors, you'll waste a lot of time trying to goad them on toward your goal, which they don't share. What we want is bilateral motivation toward a common goal. If we're smart, we don't want to be the only ones who are motivated, and others just move.

During summer 1991, we collected indoor, outdoor, and personal ozone concentration data as well as time-activity data in State College, Pennsylvania. These concentrations were measured for 23 children and their homes using passive ozone samplers. Outdoor concentrations were also measured at a stationary ambient monitoring site. Results from this pilot study demonstrate that fixed-site ambient measurements may not adequately represent individual exposures. Outdoor ozone concentrations showed substantial spatial variation between rural and residential regions. Ignoring this spatial variation by using fixed-site measurements to estimate personal exposures can result in an error as high as 127%. In addition, evidence from our pilot study indicates that ozone concentrations of a single indoor microenvironment may not represent those of other indoor microenvironments. Personal exposures were significantly correlated with both indoor (r = 0.55) and outdoor (r = 0.41) concentrations measured at home sites. Multiple regression analyses identified indoor ozone concentrations as the most important predictors of personal exposures. However, models based on time-weighted indoor and outdoor concentrations explained only 40% of the variability in personal exposures. When the model included observations for only those participants who spent the majority of their day in or near their homes, an R2 of 0.76 resulted when estimates were regressed on measured personal exposures. It is evident that contributions from diverse indoor and outdoor microenvironments must be considered to estimate personal ozone exposures accurately.

Quality Assurance (QA) via the process of review systems is a retrospective look at what was. It is a picture of the past. Any such system is bound to have limitations, because the past cannot be changed. In QA, the ultimate aim should be to educate physicians as to where they made mistakes so that they can learn how to prevent them in the future. The distribution of what mistakes can be avoided, so that all physicians can learn from others' mistakes, takes the whole team closer to the aim of real QA--preventing mistakes. The first part of this article looks at QA in general terms; the second part looks at inherent biases that should be removed so that the team reaches the goal of bona fide quality.

An investigation of high volume particle sampling and sample handling procedures was undertaken to evaluate variations of protocols being used by the U.S. Environmental Protection Agency. These protocols are used in urban ambient air studies which collect ambient and source samples for subsequent mutagenicity analysis of the organic extracts of the aerosol fraction. Specific protocol issues investigated include: (a) duration of sampling period, (b) type of filter media used to collect air particles, (c) necessity for cryogenic field site storage and dry ice shipping of filter samples, and (d) sample handling at the receiving laboratory. Six PM10 Hi-Vol samplers were collocated at an urban site in downtown Durham, North Carolina and operated simultaneously to evaluate 12 h versus 24 h collection periods and filter media choices of glass fiber, Teflon impregnated glass fiber (TIGF), and quartz fiber. Filters from the samplers plus field blanks were collected during each of 25 sampling periods. TIGF filters from two samplers were immediately placed on dry ice in the field and transported directly to cryogenic storage. TIGF, quartz, and glass fiber filters from three samplers were transported at ambient and maintained at room temperature for three to six days prior to cryogenic storage. One TIGF sample, which was collected on a previously tared filter, was subjected to controlled environment equilibration (40 percent relative humidity, 22 degrees C) for 8 to 24 h and weighed prior to cryogenic storage. All filters were subsequently stored at -70 degrees C to -80 degrees C prior to a one-time extraction and Salmonella (Ames) mutagenicity bioassay of the entire sample set.(ABSTRACT TRUNCATED AT 250 WORDS)

It is often felt that poorly controlled epileptic patients, who are taking anticonvulsant medication, are over represented in A&E departments compared to the general population. This A&E based study set out to determine whether such patients do have inadequate serum anticonvulsant levels, when they present following a seizure, to A&E departments. All epileptic patients, taking medication, who presented to the A&E departments of St. Bartholomew's and Hackney Hospitals, London, over a 4-month period were studied. Serum anticonvulsant concentrations were measured on their arrival in the departments. Forty-six patients were studied. Only 21% of anticonvulsant drug concentrations were within 'therapeutic' ranges. A total of 66% were below 'therapeutic' ranges and 13% were potentially toxic. The implication of these findings is discussed.

Common sense has to do with problem solving. In the complexities of everyday human life, we are faced time and again with the need to solve problems. In fact, every situation we face, at least at the first exposure, requires some form of problem solving. When we want food, we have to solve a series of problems from acquisition to preparation to serving and eating. When we deal with organizational needs, problem solving is the daily fare.

The turnover of classical Folch-Lees proteolipid proteins was studied after administration of [2,3-3H]tryptophan to both developing and adult rat brain. The animals were killed from 2h to 250 days after subcutaneous injections of [3H]tryptophan. The measured specific radioactivity in developing brain attained maximum value 24h after the administration of label, whereas the total radioactivity per brain reached a maximum 21 days after injection. The half-life of proteolipid protein from the measured specific radioactivity was 7-20 days, depending on the time-points used for the calculation, whereas calculation from total radioactivity between 28-77 and 91-257 days gave half-lives of 35-40 and 188 days respectively. In contrast, in animals injected at 40 days of age, the half-life from the whole-brain-radioactivity data was 188 days. The problem of the recycling of radioactivity for the synthesis of myelin proteins from either a general or a discrete amino acid pool is discussed.

In brief: A 29-year-old distance runner developed wheezing, chest tightness, and cough associated with training or racing in temperatures below 0 C. He had been running for four years and had recently moved to Colorado from Texas. The subject was treated with 2.5 mg of terbutaline orally one hour before running, and his symptoms completely resolved. Premedication was required only during the winter months. This case illustrates that with proper management and premedication tailored to the individual, athletes susceptible to exercise-induced asthma can participate at an essentially normal level throughout the year.

The Tradescantia genetic system developed by the late Dr. Arnold H. Sparrow for the study of effects of ionizing radiation is applicable to chemical mutagen detection. Early radiobiological data demonstrated that the stamen hairs were sensitive to as little as 0.25 rad of x-rays and that the number of cells showing a phenotypic change in pigmentation from blue to pink plateaus after approximately 21 days of chronic, low-level irradiation. Exposures to the air pollutants SO(2), NO(2), and O(3) and to vapors of mutagens such as 1,2-dibromoethane (DBE) and ethyl methanesulfonate (EMS) demonstrated the usefulness of the system as a detector of chemical mutagens. A significant number of phenotypic changes was observed following exposures to as little as 0.14 ppm of DBE. The maximum sensitivity of the system is obtained with long-term or chronic exposures because the response increases linearly in proportion to the duration of exposure up to 21 days. To monitor industrial sites for atmospheric mutagens a mobile laboratory was designed to support plant culture in the field. Environment-controlled growth chambers were installed in a trailer so that both ambient air fumigations and concurrent clean-air control exposures could be made. Sites monitored by the mobile laboratory were: Elizabeth, N. J.; Charleston, W. Va.; Birmingham, Ala.; Baton Rouge, La.; Houston, Tex.; Upland, Calif.; Magna, Utah; and Grand Canyon, Ariz. The latter site at Grand Canyon served as a clean air control study. Atmospheric contaminants from petroleum and chemical processing plants generated a significant number of phenotypic pigment changes that were 17 to 31% above the control levels; contaminants from steel and copper smelters, automotive combustion products and photochemical compounds were negative. Chemical analyses are underway to identify the atmospheric mutagens at the sites that showed a positive response.

A simple mathematical model of the molecular basis for the function of a diffusional sampler for dilute mixtures of gaseous contaminants in supporting gases is presented. The model is based on the movement of single molecules of the contaminant between sections of a tubular diffusion path on a step-by-step basis; the length of the step and of each section of the tube are equal to the mean free path, lambda, under the specified conditions. When the model is used, the coefficient of diffusion, D, can be calculated from lambda and the average velocity, v, of the contaminant molecule. Both lambda and v were calculated independently using equations which involved the minimum number of assumptions. The value of D so estimated was of the same order as that in the literature, differing by a factor of less than 2. It should be emphasized that the model represents a statistical, thermodynamic approach to understanding diffusional samplers, and its utility is independent of the means of estimating lambda and v for specific gas pairs.

Five tissue antigens have been identified which appear in carcinoma arising in the ovary. Antisera to a variety of human tissues were absorbed with a saline extract of normal ovary as well as plasma; five distinct antigens (A1-A4, TA) were detected in ovarian tumor extracts as well as in normal tissues. A1, A2, and A3 were widely distributed in normal tissues while A4 was found principally in buffy coat blood cells and spleen, and TA was mainly associated with normal cervix but was variably detected in liver and lung. Heating the tumor extract to 56 degrees resulted in inactivation of A1, A2, and A3. A4 was inactivated at 80 degrees, whereas TA was stable at 100 degrees. Pronase treatment readily abolished A3 activity, more slowly inactivated A1, A2, and A4, and only very slowly destroyed TA. Partial separation of the antigens was obtained by Sephadex G-200 chromatography. TA from individual benign and malignant tumors as well as normal cervix appears to be the same molecule by criteria of immunodiffusion, immunoelectrophoresis, and gel filtration. The potential use of these antigens as tracers of ovarian carcinoma is indicated.

Five tissue antigens have been identified which appear in carcinoma arising in the ovary. Antisera to a variety of human tissues were absorbed with a saline extract of normal ovary as well as plasma; five distinct antigens (A1-A4, TA) were detected in ovarian tumor extracts as well as in normal tissues. A1, A2, and A3 were widely distributed in normal tissues while A4 was found principally in buffy coat blood cells and spleen, and Ta was mainly associated with normal cervix but was variably detected in liver and lung. Heating the tumor extract to 56 degrees resulted in inactivation of A1, A2, and A3. A4 was inactivated at 80 degrees, whereas TA was stable at 100 degrees. Pronase treatment readily abolished A3 activity, more slowly inactivated A1, A2, and A4, and only very slowly destroyed TA. Partial separation of the antigens was obtained by Sephadex G-200 chromatography. TA from individual benign and malignant tumors as well as normal cervix appears to be the same molecule by criteria of immunodiffusion, immunoelectrophoresis, and gel filtration. The potential use of these antigens as tracers of ovarian carcinoma is indicated.

Myelin from developing rat brains was separated on a discontinuous sucrose gradient into subfractions of two different densities, i.e. light and heavy myelin. Electron photomicrographs showed that heavy myelin consisted primarily of large compacted multilamellar structures with a distinct intraperiod line characteristic of myelin in situ. Light myelin, on the other hand, was composed of small vesicles having a unilamellar structure. Similar to whole myelin, both membrane subfractions were highly enriched in 2',3'-cyclic nucleotide-3'-phosphohydrolase. The specific activity of the enzyme, however, showed no developmental trend. Both subfractions contained all the four major proteins characteristic of the whole myelin membrane. There were, however, quantitative differences in the relative distribution of these proteins between light and heavy myelin. Basic protein accounted for 55% and proteolipid protein for 46% of the total myelin proteins of light and heavy myelin, respectively. DM-20 (Agrawal, H.C., Burton, R. M., Fishman, M.A., Mitchell, R.F. and Prensky, A.L. (1972) J. Neurochem. 19, 2083-2089) exhibited a developmental "switch" between light and heavy myelin. Light myelin appeared to contain more DM-20 in 15- to 20-day-old rat brain, whereas the concentration of this protein was higher in heavy myelin at subsequent ages studied.

Multiple criteria must be used to relate a membrane fraction (;myelin-like') to myelin. These reported in this communication are electron microscopy, marker enzymes, sodium dodecyl sulphate-polyacrylamide-gel electrophoretic patterns and lipid composition.

Current methods for testing stool samples for hemoglobin utilize peroxidase oxidation of chemical indicators such as guaiac or benzidine. These tests have frequent false-positive and false-negative results, complicating random screening for occult gastrointestinal bleeding. The authors have developed an immunochemical test for human blood in feces using goat antibodies to hemoglobin. When employed in radial immunoassay the test is uncomplicated by cross-reaction with common human foods or other nonhemorrhagic fecal fecal constitutents. The lower limit of sensitivity for hemoglobin in stool samples is 10 mg/dl, compared with a commonly reported threshold of 100 mg/dl for peroxidase tests. The test accurately detects hemoglobin in mixtures of human blood and feces. Immunochemical identification of human blood in stool offers improved detection of lower gastrointestinal bleeding.

The advantages of clinical and mechanical combination of observations for prediction are mutually reinforced by an application of Bayesian statistics. The technique is shown to be particularly advantageous in a situation which is characterized by a paucity of observations available to suppliment a prior expert judgment. The approach also presents a basis for evaluating relative expertise and tracing the learning experience of experts. Taking the community as the organizational level of analysis, data on the classification of aged persons in Durham County, North Carolina, and data on the changes in classification of these individuals within the population over time are gathered and studied. These data are combined with clinical judgments of changes as a demonstration of the merits of the technique developed in this paper.

One-hundred-fourteen hypertensive high school students were evaluated to determine whether a distinctive clinical profile could be identified; 71 normotensive students served as controls. Selected blood chemistry determinations, urinalysis, and chest roentgenograms were done to help rule out secondary causes of hypertension. Left ventricular function was assessed by echocardiography and systolic time intervals. The hemodynamic response to exercise was also evaluated. A significant number of the subjects 14 to 18 years of age with persistent systolic and/or diastolic pressure 1.65 SD above the mean for age and sex showed the following: obesity; elevated serum triglyceride concentration; basilar hypertrophy by electrocardiogram/vectorcardiogram; electromechanical systole and pre-ejection period shorter, and the ratio of the pre-ejection period over the left ventricular ejection time lower, than mean for age and sex as determined by systolic time intervals; volume indices depressed and cardiac contractile functions elevated as determined by echocardiography; higher blood pressure at start of exercise stress test and higher peak systolic and diastolic pressures during test, and a slower return of heart rate to base line level after the test. The above findings should be useful in following the course of a young individual with essential hypertension and may provide a means of evaluating therapeutic intervention.

The findings presented here of work on the opisthobranch mollusc Pleurobranchaea californica indicate that some of the variability that has been observed in the activity of neurons during patterned motor activity may be attributable to low-dimensional chaos. We obtained long trains of action potentials (spikes) from these neurons, scanned them using adjacent temporal windows having equal widths, and converted the counts into frequency time series. These series were passed through a low-pass filter and detrended when necessary. The resulting time series gave a view of the envelopes of high-frequency bursts of spikes relating to the repetitive motor activity rather than of the intervals between spikes. Where applicable, we also compared analyses of smoothed data with the unprocessed spike intervals and found similar results for each type of time series. Autocorrelation functions of the processed data quickly decreased to zero, indicating that the long-term evolution of the time series could not be predicted from information at some given time. The first zero crossing of the autocorrelation function was used to define the lag for mapping the series into multidimensional phase space. These constructions were then used to examine the dynamics of the motor patterns directly from the state parameters of the time series: 1-D maps obtained from Poincaré slices of 2-D phase portraits, principal Lyapunov exponents, and correlation dimensions all indicated that the activity may be attributable to low-dimensional chaos. The present findings are similar to those of previous work in which equal-interval time series were obtained by interpolation of the unequal-interval spike trains. We discuss the implications of chaos and the difficulties in the application of extant dynamical tools to spike trains. An accompanying paper inquires into the ability of neural networks to read and transmit chaotic activity.

A crisis can hit any business. It can hurt cash flow, productivity, the public's faith, and the company's image. The adverse effects come in two major areas: public image and cash flow, both of which can be devastating. Lack of planning ensures maximum pain and the greatest chance of future collapse. A proactive stance can lessen the pain and give the best chance of recovery. Like a forest fire, a crisis can be sniffed early or it can destroy thousands of 'acres.' The best manager will have plans for crisis management and will be able to smell the smoke before the blaze consumes the forest.

Placental transfer of tritiated digoxin in the ewe and its effect upon the left ventricular output (LVO) of the exteriorized fetal lamb were studied. Seven ewes were given 6 mug per kilogram of body weight of tritiated digoxin daily (20 per cent of total digitalizing dose 0.03 mug per kilogram of body weight) during their entire pregnancies. The fetuses were exteriorized between 130 and 140 days of gestation, and the LVO was determined serially by the dye-dilution technique for one hour. The mean tissue concentrations in millimicrograms per gram for the ewes were: heart, 5.7 plus or minus 1.76; liver, 3.38 plus or minus 1.38, kidney, 01.9 plus or minus 12.3. Corresponding values for the fetuses were: 1.55 plus or minus 1.01, 0.78 plus or minus 0.35, and 2.48 plus or minus 1.18. The mean serum level for the ewe at the end of one hour was 1.65 ng. per milliliter plus or minus 0.48, and that for the fetus was 1.22 plus or minus 0.20. The amniotic fluid contained 1.45 ng. per milliliter plus or minus 0.27. At the end of one hour, the mean LVO of the fetus had decreased by 39 plus or minus 15 per cent of its control value. Although the fetal serum level of tritiated digoxin was similar to that found in the mother and the amniotic fluid contained a significant amount of tritiated digoxin, the fetal tissue concentration of tritiated digoxin was not sufficient to produce any demonstrable inotropic effect.

Altered hemoglobin (Hb) has been found in the feces as a sequel to an upper gastrointestinal bleed. Active Hb antigen of increased anodic mobility was detected on immunoelectrophoresis of melena stools using a goat anti-Hb. The Hb derivative was also identified in polyacrylamide gel electrophoresis using 412 nm. absorbance. The alteration could be simulated in vitro by incubation of hemolysate with duodenal juice or purified carboxypeptidase B alone, or by a mixture of carboxypeptidases A and B. Treatment of hemolysate or purified Hb with acid, gastric juice, pepsin, pancreatic juice, bile, trypsin, or chymotrypsin failed to produce the characteristic alteration. Instead, no change, or production of alpha and beta chains, or gradual but complete elimination of the Hb antigen was seen. This latter all or none pattern is presumed to prevail in the large bowel on the basis of incubations of hemoglobin-feces mixtures. Individuals documented to be bleeding into the colon were found to have at least a portion of their Hb antigen in the unaltered form by immunoelectrophoresis. This finding may be of value in identifying the general origin of a gastrointestinal bleed.

In support of Health Effects Research Studies, pulmonary function tests are periodically administered to a large number of children. The ventilatory performance of these children is being evaluated by measuring the 0.75-sec forced expiratory volume (FEV(0.75)) with a waterless mechanical volume spirometer used in conjunction with an electronic timing unit. During a 1-yr testing period, operation with the volume spirometer and the EPA designed electronic timing unit proved to be highly successful. The volume spirometer was found to be more advantageous in conducting tests at remote field stations than the water spirometer and other electronic instruments which measure flow rate with a transducer element. The volume spirometer is lightweight, easy to operate, and has the capability of easy and accurate field calibration when used in conjunction with the electronic timing unit. Presently the volume spirometer and EPA designed electronic timing package are employed in all Community Health and Surveillance System (CHESS) pulmonary function testing studies.