Showing papers by "Sewanee: The University of the South published in 1993"

Decoding algebraic-geometric codes up to the designed minimum distance

Abstract: A simple decoding procedure for algebraic-geometric codes C/sub Omega /(D,G) is presented. This decoding procedure is a generalization of Peterson's decoding procedure for the BCH codes. It can be used to correct any ((d*-1)/2) or fewer errors with complexity O(n/sup 3/), where d* is the designed minimum distance of the algebraic-geometric code and n is the codelength. >

Application of a random walk model to geographic distributions of animal mitochondrial DNA variation.

Abstract: In rapidly evolving molecules, such as animal mitochondrial DNA, mutations that delineate specific lineages may not be dispersed at sufficient rates to attain an equilibrium between genetic drift and gene flow. Here we predict conditions that lead to nonequilibrium geographic distributions of mtDNA lineages, test the robustness of these predictions and examine mtDNA data sets for consistency with our model. Under a simple isolation by distance model, the variance of an mtDNA lineage's geographic distribution is expected be proportional to its age. Simulation results indicated that this relationship is fairly robust. Analysis of mtDNA data from natural populations revealed three qualitative distributional patterns: (1) significant departure of lineage structure from equilibrium geographic distributions, a pattern exhibited in three rodent species with limited dispersal; (2) nonsignificant departure from equilibrium expectations, exhibited by two avian and two marine fish species with potentials for relatively long-distance dispersal; and (3) a progression from nonequilibrium distributions for younger lineages to equilibrium distributions for older lineages, a condition displayed by one surveyed avian species. These results demonstrate the advantages of considering mutation and genealogy in the interpretation of mtDNA geographic variation.

Rule-based approach to computing module cohesion

Abstract: Stevens, Myers, and Constantine introduced the notion of cohesion, an ordinal scale of seven levels that describes the degree to which the actions performed by a module contribute to a unified function (1974). They provided rules, termed as associative principles to examine the relationships between processing elements of a module and designate a cohesion level to it. Stevens et al., however, did not give a precise definition for the term processing element. The author interprets the output variables of a module as its processing elements. Stevens et al.'s associative principles are transformed to relate the output variables based on their data and control dependence relationships. What results is a rule-based approach to computing cohesion. Experimental results show that, but for temporal cohesion, the cohesion associated to a module under this reinterpretation and that due to the original definitions are identical for all examples. >

Post-traumatic Stress Disorder in Adolescents after a Hurricane

Abstract: A school-based study conducted in 1990, 1 year after Hurricane Hugo, investigated the frequency and correlates of post-traumatic stress disorder (PTSD) in 1,264 adolescents aged 11-17 years residing in selected South Carolina communities. Data were collected via a 174-item self-administered questionnaire that included a PTSD symptom scale. A computer algorithm that applied decision rules of the Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised to the symptoms reported was used to assign a diagnosis of PTSD and to designate the number of individuals who met the reexperiencing (20%), avoidance (9%), and arousal (18%) criteria. Rates of PTSD were lowest in black males (1.5%) and higher, but similar, in the remaining groups (3.8-6.2%). Results from a multivariable logistic model indicated that exposure to the hurricane (odds ratio (OR) = 1.26, 95% confidence interval 1.13-1.41), experiencing other violent traumatic events (OR = 2.46, 95% confidence interval 1.75-3.44), being white (OR = 2.03, 95% confidence interval 1.12-3.69) and being female (OR = 2.17, 95% confidence interval 1.15-4.10) were significant correlates of PTSD.

Organization of cortical microtubules in graviresponding maize roots

Abstract: Immunofluorescence labeling of cortical microtubules (MTs) was used to investigate the relationship between MT arrangement and changes in growth rate of the upper and lower sides of horizontally placed roots of maize (Zea mays L. cv. Merit). Cap cells and cells of the elongation zone of roots grown vertically in light or darkness showed MT arrangements that were transverse (perpendicular) to the growth direction. Microtubules of cells basal to the elongation zone typically showed oblique orientation. Two hours after horizontal reorientation, cap cells of gravicompetent, light-grown and curving roots contained MTs parallel to the gravity vector. The MT arrangement on the upper side of the elongation zone remained transverse but the MTs of the outer four to five layers of cortical cells along the lower side of the elongation zone showed reorientation parallel to the axis of the root. The MTs of the lower epidermis retained their transverse orientation. Dark-grown roots did not curve and did not show reorientation of MTs in cells of the root cap or elongation zone. The data indicate that MT depolymerization and reorientation is correlated with reduction in growth rate, and that MT reorientation is one of the steps of growth control of graviresponding roots.

Influence of Density on Growth of White-Tailed Deer

Abstract: Age and mass data from 9,956 white-tailed deer ( Odocoileus virginianus ) from South Carolina were used to examine the relationship between growth patterns of each sex and population density. Growth parameters for 16 annual cohorts born between 1965 and 1981 were derived with a Richards function; population sizes were estimated with a competing risks model. There were significant relationships of growth parameters for males, but not for females, with population density. Males grew more slowly and reached smaller adult masses at the highest population densities. The growth-density association was weakest in young deer and strongest in males 1.5–2.5 years of age. Sex-specific differences in the growth-density relationship may be due to energetic costs associated with competition among males for mates or to a higher use of marginal habitats by males than by females. One consequence of sex-specific relationships of density with growth rates and adult size is a decrease in sexual dimorphism in size at greater population densities.

The discrete collocation method for nonlinear integral equations

Abstract: The collocation method for solving linear and nonlinear integral equations results in many integrals which must be evaluated numerically. In this paper, we give a general framework for discrete collocation methods, in which all integrals are replaced by numerical integrals. In some cases, the collocation method leads to solutions which are superconvergent at the collocation node points. We consider generalizations of these results, to obtain similar results for discrete collocation solutions. Lastly, we consider a variant due to Kumar and Sloan for the collocation solution of Hammerstein integral equations

Passcal instrument performance during the Tibetan Plateau Passive Seismic Experiment

Abstract: Summary The PASSCAL instrumentation performed very well in the Tibetan Plateau Seismic Experiment. This experiment has demonstrated the viability of recording high-quality broadband data at temporary sites in extreme environments. It also highlights some areas where further development is needed. Primarily, more effort is needed to develop more versatile triggering options for the PASSCAL instruments. Such developments could both increase the instrument9s success at recording low magnitude teleseismic events for travel-time studies and save disk space when recording local events, thus further increasing the feasibility of long deployments in remote regions. Although the use of the PASSCAL instrument9s calibration circuitry for sensor recentering is a valuable technique, more experience is needed in the construction of sensor pads to minimize tilt problems that require site visits to relevel the seismometer such as we experienced at a few sites in the winter. This may also lead to improved low-frequency noise levels, although signals with periods greater than 200 sec can be recovered from these sites. The most exciting aspect of the data we have collected is its broad frequency content and spatial density. We anticipate that this type of experiment will be increasingly useful in the study of lithospheric interactions as well as deep Earth structure. This data was delivered to the IRIS Data Management Center in early September 1993 and is available to the community. Two other broadband passive-seismic experiments, the Baikal Rift experiment (Gao et al. 1992) and the Rocky Mountain Front experiment (Sheehan et al. 1992) should be delivered to the IRIS DMC in the Fall of 1993 as well. Temporary broadband seismic experiments represent an extension of the permanent Global Seismic Network (GSN). We encourage the seismological community to incorporate these data into any research using GSN data in order to maximize the potential utility of this new mode of seismic recording.

Perioperative antibiotic prophylaxis and wound infection following breast surgery

Abstract: The effectiveness of perioperative antibiotic prophylaxis against wound infections following breast surgery was investigated by meta-analysis of published data from a randomized clinical trial and an observational data set, which included a total of 2587 surgical procedures, including excisional biopsy, lumpectomy, mastectomy, reduction mammoplasty and axillary node dissection. There were 98 wound infections (3.8%). Prophylaxis was used for 44% (1141) of these procedures, cephalosporins accounted for 986 (86%) of these courses of antibiotics. Prophylaxis prevented 38% of infections, after controlling for operation type, duration of surgery and participation in the randomized trial (Mantel-Haenszel Odds Ratio = 0.62, 95% confidence interval = 0.40-0.95, P = 0.03). There was no significant variation in efficacy according to operation type or duration. We conclude that antibiotic prophylaxis significantly reduces the risk of postoperative wound infection following these commonly performed breast procedures.

Potentiometric and Fiber Optic Sensors for pH Based on an Electropolymerized Cobalt Porphyrin

Abstract: Potentiometric and fiber optic sensors based on polymer films were prepared by electrodeposition of the ion-carrier monomer cobalt(II) tetrakis (p-hydroxyphenyl)porphyrin, [Co(p-OH)TPP]. Fiber optic sensors were developed by electropolymerization of the porphyrin on the surface of indium(tin) oxide glass slides. The optical sensors were highly selective to pH, presenting minimal interferences from anions. They had a linear response from pH 8 to 12. Potentiometric sensors were prepared from porphyrin films electrodeposited on glassy-carbon disk electrodes. These electrodes gave a near-Nernstian response to pH from pH 2 to 12 with minimal interferences

Using Elderly Educators to Increase Colorectal Cancer Screening

Abstract: This article reports on the elderly educator method, a practical and economical intervention that was used for increasing the rate of return of fecal occult blood sampling in colorectal screening among 171 socioeconomically disadvantaged older persons. Two methods that used elderly educators had an overall response rate of more than 60%. Logistic regression shows a statistically significant difference between two methods that used elderly educators and two methods that did not.

The design and application of residualizing labels for studies of protein catabolism.

Abstract: Residualizing labels (R-labels) are chemical tags for proteins, originally designed for studies of the sites and mechanisms of plasma protein catabolism. The labels consist of oligosaccharides derivatized with radioactive, fluorescent, nuclear magnetic resonance (NMR), or positron emission tomography (PET) active reporter molecules. Because these glycoconjugates generally have molecular masses in excess of 500 daltons and are hydrophilic, they are relatively membrane impermeant. They are also designed to be resistant to lysosomal hydrolases and are therefore retained inside cells with half-lives of 2-5 days after endocytosis and degradation of the carrier protein. The R-labels thus provide a convenient means for following the cumulative uptake and catabolism of proteins by cells in vivo or in vitro. This review summarizes how R-labels have provided insights into the sites and regulation of the turnover of circulating proteins, and pathways for intracellular transport and degradation of endocytosed proteins. The potential use of R-labels for noninvasive studies of the distribution of protein pharmaceuticals in vivo is also discussed.

Healthy Cities and change: social movement or bureaucratic tool?

Abstract: Healthy Cities is seen as a vision, project and movement. Its wide appeal leaves it open to losing touch with the core values envisaged by the originators of Healthy Cities. This paper considers the outcomes Healthy Cities should aim for in Australia and the processes by which they can be achieved. It identifies the political ideology underlying the Ottawa Charter as social democratic and collectivist. Economic rationalism, individualism and misplaced professionalism are discussed as blocks to achieving Healthy Cities. It is suggested that professional workers seeking to promote health should operate within a 'health promotion winners' triangle' as many do currently. The paper concludes by arguing that Healthy Cities should ensure complacency does not permit a taken-for-granted economism, individualism and professionalism to dominate agendas for change and suggests ways in which collaborations with forces inside and outside bureaucracies may assist the processes of achieving healthier cities.

Repair of N-methylpurines in the mitochondrial DNA of xeroderma pigmentosum complementation group D cells.

Abstract: Previous work from our laboratory has shown that mitochondria are able to repair N-methylpurines formed by methylnitrosourea (MNU). However, it is unclear as to whether repair mechanisms that remove this type of lesion in nuclear DNA also remove these adducts in mitochondria. To address this question, we studied repair of MNU-induced N-methylpurines in the mitochondrial DNA from xeroderma pigmentosum complementation group D (XP-D) cells using quantitative Southern blot analysis and 32P-end-labeling techniques. These cells have been reported to be defective in the repair of this type of lesion in their nuclear genome. WI 38 cells were used as normal controls for these studies. Both XP-D fibroblasts and WI 38 cells were exposed to 0.5 mM MNU for 1 h. Following an 8 h repair period, 61% of N-methylpurines were repaired in the mitochondrial genome of XP-D cells and 39% of these lesions were repaired in WI 38 cells. After 24 h, XP-D cells had repaired 77% of the N-methylpurines in their mitochondrial genome, while WI 38 cells had 44% repair of this type of damage. During this same 24 h time period, 81.5% of the N7-methylguanines had been removed from the total cellular DNA of the WI 38 cells compared to only 38.3% repair of this lesion in the XP-D cells. Thus, XP-D cells, though deficient in the repair of N-methylpurines in their nuclear genome, are proficient in the repair of this type of damage in their mitochondria, suggesting that the mechanisms to repair N-methylpurines in the nuclear and mitochondrial genomes of these cells are different.

Body Mass Index and Fat Patterning as Correlates of Lipids and Hypertension in an Elderly, Biracial Population

Abstract: BACKGROUND Associations between anthropometric measurements of fat patterning and risk factors for cardiovascular disease have been demonstrated in several populations composed predominantly of White, young or middle-aged adults Fat pattern changes with aging and older adults tend to have a more central or abdominal fat distribution Few investigators have focused on relationships of fat patterning with plasma lipids or blood pressure in older adults or in Blacks METHODS Body mass index (BMI), fat patterning, plasma lipids, and blood pressure were examined in participants of the Charleston Heart Study Subjects included 216 White men, 95 Black men, 320 White women, and 155 Black women with a mean age of 727 years (range 61-106) RESULTS In each of the four race and gender groups, BMI was inversely correlated with HDL cholesterol and positively correlated with hypertension BMI tended to be positively associated with total cholesterol, although the relationships were not statistically significant After controlling for the effects of BMI, age, smoking, and alcohol intake (using regression analysis), waist to hip ratio was associated with cholesterol levels in the White men and women and the Black men In similar models, waist circumference in Black women was inversely associated with HDL There were no significant relationships between waist to hip ratio and hypertension in any of the groups after controlling for BMI CONCLUSION In an elderly cohort, waist to hip ratio was associated with plasma lipids, but not with hypertension, when the effects of BMI were held constant

An Assessment of Cumulative Sum Charts for Authorship Attribution

Abstract: Issue Section: Articles © Oxf ord University Press You do not currently have access to this article. Download all figures Morton and Michaelson have proposed using cumulative sum charts of various word classes as a method of authorship attribution. Their method has been criticized for its lack of a firm statistical basis and its subjective nature. We present an alternate method, based on weighted cumulative sums, that has a firm basis in statistics and uses rigorous, well-established testing procedures. The results of experiments conducted to test the procedures. The result of experiments conducted to test the validity of weighted cumulative sums for authorship attribution are also presented. These results indicate cumulative sums are not consistently reliable indicators of authorship Sign in Don't already have an Oxford Academic account? Register Forg ot password? Don't have an account? Oxford Academic account Email address / Username

Measurements of computer anxiety: A review

Abstract: The objective of this article is to present a review and discussion of scales and questionnaires developed to assess computer anxiety. Included are descriptions of the scales, scale development procedures, and reliability and validity testing. Research questions generated and examined with the scales are also included. Finally, problems with reliability and validity testing are presented along with an assessment of future directions of computer anxiety research.

Adaptations of the branchial ectoparasite Probopyrus pandalicola (Isopoda: Bopyridae) for survival and reproduction related to ecdysis of the host, Palaemonetes pugio (Caridea: Palaemonidae)

Abstract: Survival of the branchial ectoparasite Probopyrus pandalicola through ecdysis of the host, Palaemonetes pugio, was studied by observing infected shrimps before and after ecdysis and directly with time-lapse video. The parasite pair retained its position through 97.3% of 112 host ecdyses. This observation and positive correlations between parasite and host size support the hypothesis that bopyrid isopods remain on and grow together with their host. Video recordings of shrimp ecdysis showed that the female and male maintain their position rather than being cast off and reentering the host branchial chamber. Observations on exuviae from parasitized shrimps and from video recordings suggest that the female parasite avoids being discarded with the molt skin by immediately attaching to the newly exposed inner lining of the gill cover as the shrimp backs out of its exuviae. Reproductive activities of the parasite relative to host molting were studied. Epicaridium larvae were released from the host branchial chamber several hours to 5 days before the host molt. Spawning by the parasite female took place within several hours (median = 12 h) after host ecdysis. Expulsion of exuvial fragments of female parasites from the host branchial chamber was observed in 2 video recordings prior to spawning. In several video recordings, the usually inactive male moved from its site on the female abdomen up to and inside the female marsupium after the host molt and before female spawning, presumably to inseminate the female. Females from which males had been removed failed to produce a brood after the next host molt, tentatively supporting the hypothesis that females must be inseminated prior to each spawning.

Ultrastructure of the gravid uterus of Hymenolepis diminuta (Platyhelminthes: Cestoda).

Abstract: The fine structure of the uterus in gravid proglottids of Hymenolepis diminuta was examined by standard techniques for scanning and transmission electron microscopy. The uterus consisted of a syncytial uterine epithelium attached to the medullary parenchyma through a thin extracellular basal matrix. The epi- thelium contained prominent nuclei in the juxtalumenal cytoplasm. The cytoplasm was dominated by extensive granular endoplasmic reticulum, with dilated cisternae containing an electron-lucent material and widely scat- tered electron-dense spherical bodies. No Golgi body or other agranular endomembrane component was ob- served, but the epithelium contained numerous free ribosomes and a few mitochondria. The apical plasma membrane was folded into long microlamellae. Epithelial and epitheliomesenchymal folds and villi resulted in a compartmentalized uterine lumen, with each chamber containing 1 to several eggs. These data suggest a high level of synthetic activity within the uterine epithelium, but the chemical products and functional significance of this activity are not yet known. tained in the laboratory and thus are not widely studied by most tapeworm biologists. The vast majority of experimental tapeworm research is conducted with Hymenolepis diminuta, which is easily maintained in the laboratory and is oc- casionally parasitic in humans and some do- mesticated animals. However, with the excep- tion of a single scanning electron micrograph published in a review by Lumsden and Specian (1980), nothing is known about the uterine ul- trastructure of this species. Because of the im- portance of H. diminuta to tapeworm research, the present study was undertaken to elucidate the ultrastructure of its gravid uterus.

Behavioral Intensive Care Unit (BICU): A New Concept in the Management of Acute Agitated Behavior in Elderly Demented Patients

Abstract: Intensive care units were developed in response to the perceived need for increased monitoring in critically ill medical patients. The same principle applies to elderly patients with severe agitated behaviors. These patients can be served by the Geriatric Behavioral Intensive Care Unit (BICU). The uniqueness of the program results from the application of a behavioral and environmental approach to the treatment of agitated behavior. The underlying strategy in the treatment process is to enhance the patient's ability to adapt to his or her home environment. Preliminary results have been encouraging, showing positive outcomes in diverse areas such as low level of institutional placement, patient quality of life, and caregiver symptoms of burden and depression.

In vivo measurement of the low-frequency dielectric spectra of frog skeletal muscle.

Abstract: Capacitance, conductance and dielectric loss spectra are obtained, in vivo, for a number of electrode separations in the gastrocnemius muscle of a frog. At each frequency the reciprocals of these parameters are plotted versus electrode separation. From the slopes of the resulting lines the complex permittivity and the conductivity of the muscle can be determined, with electrode effects eliminated. The sequence of power-law responses which is found is consistent with the fractal model proposed by Dissado. The electrical properties measured in vivo with needle electrodes are similar to those measured with surface electrodes for frequencies between 1 kHz and 1 MHz.

Feeding Behavior, Aggression, and the Conservation Biology of Flamingos: Integrating Studies of Captive and Free-ranging Birds

Abstract: Flamingos (Aves, Phoenicopteridae) represent an ancient lineage of long-legged, microphagous, colonial wading birds. Although often perceived as tropical, flamingo distribution is more closely tied to the great deserts of the world, and to hypersaline sites, than it is to equatorial regions. Many aspects of flamingo behavior and ecology can be studied in captivity. Experimental studies involving captive birds, when combined with observational studies of free-ranging birds, offer researchers opportunities to address questions that are unanswerable with field work alone. Zoo populations of flamingos are prime candidates for such studies. Here, we use samples of our own work to illustrate the synergistic effects of combining zoo and field research

Micronuclei in adult and foetal mice exposed in vivo to heliotrine, urethane, monocrotaline and benzidine.

Abstract: The level of clastogenic damage in mice following in vivo adult and transplacental exposure to benzidine, heliotrine, monocrotaline and urethane was compared using the micronucleus (MN) assays of polychromatic erythrocytes (PCE) found in mouse adult bone marrow and foetal liver. Saline was used as a negative control. Swiss-albino mice (gestation 17–19 days) were given a single acute intraperitoneal injection. Animals sacrificed 21 h after 0.75 LD50 of each chemical had significantly increased frequencies f micronucleated PCE in adult and foetal tissues (p

Biogenic amines in silage. 1. The occurrence of biogenic amines in silage.

Abstract: In laboratory silages made from orchardgrass, red clover and oats, significant levels of toxic biogenic amines were found. The most widespread were putrescine and cadaverine, concentrations of spermidine, spermine and histamine were ten times lower on average. Of the amines considered, putrescine content seems to be the most sensitive indicator of the extent of putrefaction in silages. A relationship between the putrescine contents and the degree of proteolysis was found. The biogenic amine content is closely connected with both the variety of crop ensiled and even more so with the method and the efficiency of preservation. Neither the application of formic acid nor wilting suppressed the formation of any of the amines in silages selectively. Formic acid suppressed the total concentration of amines to 23% as compared with controls. The highest levels of amines were found in orchardgrass and oat silages; smaller amounts were detected in clover silages. In the case of very poorly preserved silage 100-150 g of toxic amines can be consumed by a cow in a day. This could have a deleterious effect on the physiological condition and the performance of livestock.

Clinical rheumatology training of Australian medical students. A national survey of 1991 graduates.

Abstract: Objective: To describe Australian medical graduates' knowledge, experiences and practical training in rheumatology and their attitudes towards rehabilitation and disability. Design: Cross-sectional survey of all interns at randomly selected hospitals in each State. Participants: 382 Australian interns at 12 hospitals surveyed in the first week of their 1991 internship. Results:New interns demonstrated little experience with soft tissue rheumatism, with only 45% reporting they had examined a patient with bursitis and 22% one with epicondylitis. There was considerable dissatisfaction with the teaching of assessment of low back pain, regardless of the amount of formal rheumatology teaching the graduates had experienced, with only 22% rating it as good or excellent. There was little evidence that students are exposed to the social dimensions of chronic illness; only 32% of students reported that they had been shown how to assess a patient's psychological adjustment to illness. Only 22% felt competent at assessing disability and handicap and less than half of the graduates studied had ever attended a clinic where there was a physiotherapist. Graduates who had never been attached to either a rheumatology ward or an outpatients clinic (17%) were less likely to have examined a patient with gout (P < 0.001), osteoarthritis (P < 0.01), or chronic low back pain (P < 0.05), and were more likely to report dissatisfaction with training in rheumatology. Conclusion: This survey suggests that there are significant problems in the training of medical students in musculoskeletal disorders, particularly in relation to the assessment of disability and the appreciation of psychosocial factors.