Showing papers by "Dalhousie University published in 1998"
TL;DR: Findings revealed that catastrophizing, measured by the Pain Catastrophizing Scale, was significantly correlated with patients' reported pain intensity, perceived disability and employment status and was associated with disability independent of the levels of depression and anxiety.
Abstract: The present study examined the role of catastrophizing in predicting levels of pain and disability in a sample of individuals who had sustained soft-tissue injuries to the neck, shoulders or back following work or motor vehicle accidents. Participants were 86 (27 men, 59 women) consecutive referrals to the Atlantic Pain Clinic, a multidisciplinary treatment centre for the management of persistent pain disorders. Findings revealed that catastrophizing, measured by the Pain Catastrophizing Scale (PCS; Sullivan, M.J.L. et al., Psychol. Assess., 7 (1995) 524-532) was significantly correlated with patients' reported pain intensity, perceived disability and employment status. The results of a regression analysis further showed that catastrophizing contributed to the prediction of disability over and above the variance accounted for by pain intensity. In addition, catastrophizing was associated with disability independent of the levels of depression and anxiety. The rumination subscale of the PCS was the strongest predictor of pain and disability. Theoretical and clinical implications of the findings are discussed.
581 citations
TL;DR: This article argued that the strong focus on emotional distress as the marker of coping efforts has masked the importance of social functions, processes and outcomes in coping with life stress, particularly the role of communal coping.
Abstract: This paper argues for a substantial re-conceptualization of coping. The strong focus on emotional distress as the marker of coping efforts has masked the importance of social functions, processes and outcomes in coping with life stress, particularly the role of communal coping. Communal coping is a cooperative problem-solving process salient in coping with both individual and collective stressors. It involves the appraisal of a stressor as `our' issue and cooperative action to address it. Beyond its important role in coping, communal coping is endemic to notions of social integration, interdependence and close relationships, and may underlie the resilience of families and other social units dealing with stressful life events. The authors present a framework that distinguishes communal coping from other individual and social coping processes. We also provide an analysis of benefits and costs of communal coping, a discussion of key factors in its utilization, and suggestions for further research on the func...
565 citations
TL;DR: The diagnosis of Q fever relies mainly upon serology, the most commonly used method being the immunofluorescence assay, and serological testing for Q fever should always be done for a patient with a febrile illness and negative blood cultures.
Abstract: My colleagues and I compliment Dr. Fournier and coauthors on an excellent review (3). However, we were surprised to read the statement that there is no commercially available enzyme-linked immunosorbent assay (ELISA) for the serological detection of Q fever, since papers describing these assays have been published (1, 2, 4). These ELISAs, for the detection of specific immunoglobulin M (IgM), IgA, and IgG antibodies produced during Q fever, are available from PanBio Pty Ltd., Brisbane, Australia. All tests use a common assay method, including the provision of cutoff control sera, and take less than an hour to perform. The availability of these tests in part contradicts the claim made by Fournier et al. (3) that ELISA is a more laborious technique than immunofluorescence assay (IFA) and requires considerable experience in interpreting the results. The IgG ELISA has been shown to have good correlation with immunofluorescence, and all patients determined to have a significant level of antibody by IFA were positive in the PanBio test (2, 4). The IgM and IgA ELISAs showed a significant correlation with the complement fixation test, with sensitivity of 100% and specificity of 89% being reported for each assay (1).
555 citations
TL;DR: The role of environmental variability in the survival of juvenile fish and shellfish is reviewed by examining the success of previously published environment–recruitment correlations when tested with new data and suggesting that future progress will require testing general hypotheses using data from many populations.
Abstract: I review the role of environmental variability in the survival of juvenile fish and shellfish by examining the success of previously published environment–recruitment correlations when tested with new data. The proportion of published correlations that have been verified upon retest is low. There is one generalization that stands out: correlations for populations at the limit of a species' geographical range have often remained statistically significant when re-examined. An examination of environment–recruitment correlations that were reviewed 13 years ago by Shepherd and co-workers shows that only 1 out of 47 reviewed studies is currently used in the estimation of recruitment in routine assessments. The results suggest that future progress will require testing general hypotheses using data from many populations.
524 citations
TL;DR: Estimates of time to stability in pneumonia and explicit criteria for defining stability can provide an evidence-based estimate of optimal length of stay, and outline a clinically sensible approach to improving the efficiency of inpatient management are outlined.
Abstract: Context.—Many groups have developed guidelines to shorten hospital length of
stay in pneumonia in order to decrease costs, but the length of time until
a patient hospitalized with pneumonia becomes clinically stable has not been
established.Objective.—To describe the time to resolution of abnormalities in vital signs,
ability to eat, and mental status in patients with community-acquired pneumonia
and assess clinical outcomes after achieving stability.Design.—Prospective, multicenter, observational cohort study.Setting.—Three university and 1 community teaching hospital in Boston, Mass,
Pittsburgh, Pa, and Halifax, Nova Scotia.Patients.—Six hundred eighty-six adults hospitalized with community-acquired pneumonia.Main Outcome Measures.—Time to resolution of vital signs, ability to eat, mental status, hospital
length of stay, and admission to an intensive care, coronary care, or telemetry
unit.Results.—The median time to stability was 2 days for heart rate (≤100 beats/min)
and systolic blood pressure (≥90 mm Hg), and 3 days for respiratory rate
(≤24 breaths/min), oxygen saturation (≥90%), and temperature (≤37.2°C
[99°F]). The median time to overall clinical stability was 3 days for
the most lenient definition of stability and 7 days for the most conservative
definition. Patients with more severe cases of pneumonia at presentation took
longer to reach stability. Once stability was achieved, clinical deterioration
requiring intensive care, coronary care, or telemetry monitoring occurred
in 1% of cases or fewer. Between 65% to 86% of patients stayed in the hospital
more than 1 day after reaching stability, and fewer than 29% to 46% were converted
to oral antibiotics within 1 day of stability, depending on the definition
of stability.Conclusions.—Our estimates of time to stability in pneumonia and explicit criteria
for defining stability can provide an evidence-based estimate of optimal length
of stay, and outline a clinically sensible approach to improving the efficiency
of inpatient management.
483 citations
TL;DR: An understanding of the contribution of adenosine to pain processing is important for understanding how caffeine produces adjuvant analgesic properties in some situations, but might interfere with the optimal benefit to be derived from others.
474 citations
TL;DR: This paper showed that while incomes may be pooled for some categories of consumption (e.g. housing), the income pooling hypothesis must be rejected for others (i.e., education and child care).
Abstract: This paper uses microdata from the 1992 Statistics Canada Family Expenditure Survey to provide evidence that male and female incomes do not always exert identical influences on household expenditures. The novelty of the paper lies in its demonstration that, while incomes may be pooled for some categories of consumption (e.g. housing), the income pooling hypothesis must be rejected for others. We also go beyond simply rejecting the pooling hypothesis to ask how male versus female income is used. Our results stress the on-going importance of traditional gender roles. For example, we find that expenditures on child care increase only with women’s incomes_higher male income is not associated with higher expenditure on child care even when both spouses are full-time, full-year paid workers.
440 citations
TL;DR: PC is a powerful inducer of ischemic brain tolerance as reflected by preservation of brain tissue and motor function and the importance of protein synthesis in PC-induced IT is evaluated.
Abstract: Background and Purpose—A short duration of ischemia (ie, ischemic preconditioning [PC]) can provide significant brain protection to subsequent ischemic events (ie, ischemic tolerance [IT]). The present series of studies was conducted to characterize the temporal pattern of a PC paradigm, to systematically evaluate the importance of protein synthesis in PC-induced IT, and to explore candidate gene expression changes associated with IT. Methods—Temporary middle cerebral artery occlusion (MCAO) (10 minutes) was used for PC. Various periods of reperfusion (ie, 2, 6, and 12 hours and 1, 2, 7, 14, and 21 days) were allowed after PC and before permanent MCAO (PMCAO) (n=7 to 9 per group) to establish IT compared with non-PC (sham-operated) rats (n=22). Infarct size, forelimb and hindlimb motor function, and cortical perfusion (laser-Doppler flowmetry; n=9 per group) were measured after PMCAO. The effects of the protein synthesis inhibitor cycloheximide administered just before PC (n=13 to 17) or administered long...
427 citations
TL;DR: The ketogenic diet is effective in substantially decreasing difficult-to-control seizures and can successfully be administered in a wide variety of settings.
Abstract: Objective To determine the efficacy of the ketogenic diet in multiple centers. Design A prospective study of the change in frequency of seizures in 51 children with intractable seizures who were treated with the ketogenic diet. Setting Patients were enrolled from the clinical practices of 7 sites. The diet was initiated in-hospital and the patients were followed up for at least 6 months. Patients Fifty-one children, aged 1 to 8 years, with more than 10 seizures per week, whose electroencephalogram showed generalized epileptiform abnormalities or multifocal spikes, and who had failed results when taking at least 2 appropriate anti-epileptic drugs. Intervention The children were hospitalized, fasted, and a 4:1 ketogenic diet was initiated and maintained. Main Outcome Measures Frequency of seizures was documented from parental calendars and efficacy was compared with prediet baseline after 3, 6, and 12 months. The children were categorized as free of seizures, greater than 90% reduction, 50% to 90% reduction, or lower than 50% reduction in frequency of seizures. Results Eighty-eight percent of all children initiating the diet remained on it at 3 months, 69% remained on it at 6 months, and 47% remained on it at 1 year. Three months after initiating the diet, frequency of seizures was decreased to greater than 50% in 54%. At 6 months, 28 (55%) of the 51 initiating the diet had at least a 50% decrease from baseline, and at 1 year, 40% of those starting the diet had a greater than 50% decrease in seizures. Five patients (10%) were free of seizures at 1 year. Age, sex, principal seizure type, and electroencephalogram were not statistically related to outcome. Conclusion The ketogenic diet is effective in substantially decreasing difficult-to-control seizures and can successfully be administered in a wide variety of settings.
421 citations
TL;DR: Diagnostic criteria that may define a concise, recognizable syndrome with a single pathogenetic basis are presented and the current understanding of the management for this complex and chronic multiple congenital anomaly condition is summarized.
Abstract: CHARGE association is a nonrandom pattern of congenital anomalies that occurs together more frequently than one would expect on the basis of chance. This common multiple anomaly condition has an estimated prevalence of 1:10,000. The number of children diagnosed with CHARGE association is increasing, owing presumably to greater awareness of this condition and advances in the care of complex, chronically ill children, resulting in improved survival and outcome. This review of CHARGE association presents diagnostic criteria that may define a concise, recognizable syndrome with a single pathogenetic basis. This review also summarizes our current understanding of the management for this complex and chronic multiple congenital anomaly condition and discusses the pathogenetic basis for this condition.
411 citations
TL;DR: A split intein capable of protein trans-splicing is identified in a DnaE protein of the cyanobacterium Synechocystis sp.
Abstract: A split intein capable of protein trans-splicing is identified in a DnaE protein of the cyanobacterium Synechocystis sp. strain PCC6803. The N- and C-terminal halves of DnaE (catalytic subunit α of DNA polymerase III) are encoded by two separate genes, dnaE-n and dnaE-c, respectively. These two genes are located 745,226 bp apart in the genome and on opposite DNA strands. The dnaE-n product consists of a N-extein sequence followed by a 123-aa intein sequence, whereas the dnaE-c product consists of a 36-aa intein sequence followed by a C-extein sequence. The N- and C-extein sequences together reconstitute a complete DnaE sequence that is interrupted by the intein sequences inside the β- and τ-binding domains. The two intein sequences together reconstitute a split mini-intein that not only has intein-like sequence features but also exhibited protein trans-splicing activity when tested in Escherichia coli cells.
TL;DR: Joint visual attention does not reliably appear prior to 10 months of age, a gaze-following response can be learned, and simple learning is not sufficient as the mechanism through which joint attention cues acquire their signal value.
Abstract: Two experiments examined the origins of joint visual attention with a training procedure. In Experiment 1, infants aged 6-11 months were tested for a gaze-following (joint visual attention) response under feedback and no feedback conditions. In Experiment 2, infants 8-9 months received feedback for either following the experimenter's gaze (natural group) or looking to the opposite side (unnatural group). Results of the 2 experiments indicate that (a) joint visual attention does not reliably appear prior to 10 months of age, (b) from about 8 months of age, a gaze-following response can be learned, and (c) simple learning is not sufficient as the mechanism through which joint attention cues acquire their signal value.
TL;DR: In this article, the authors describe a number of initiatives, particularly in the United States and Canada, which are categorized as engineering or self-designing, and list 11 characteristics of eco-industrial parks which are emerging from the existing projects.
TL;DR: The authors found that the older the family business and the longer the respondent's tenure in that business, the more important these attributes became, despite the attention the literature has given to those attributes.
Abstract: Respondents from 485 family firms in Canada rated integrity and commitment to the business as the most important attributes of a successor. Results indicated that the older the family business and the longer the respondent's tenure in that business, the more important these attributes became. Birth order and gender were rated the least important, despite the attention the literature has given to those attributes.
TL;DR: It is shown that MtzR results from loss of oxygen‐insensitive NADPH nitroreductase activity, and suggests that many rdxA (MtzR) mutations may have been selected by prior use of Mtz against other infections.
Abstract: Metronidazole (Mtz) is a critical component of combination therapies that are used against Helicobacter pylori, the major cause of peptic ulcer disease. Many H. pylori strains are Mtz resistant (MtzR), however, and here we show that MtzR results from loss of oxygen-insensitive NADPH nitroreductase activity. The underlying gene (called 'rdxA') was identified in several steps: transformation of Mtz-susceptible (MtzS) H. pylori with cosmids from a MtzR strain, subcloning, polymerase chain reaction (PCR) and DNA sequencing. We also found that (i) E. coli (normally MtzR) was rendered MtzS by a functional H. pylori rdxA gene; (ii) introduction of rdxA on a shuttle vector plasmid into formerly MtzR H. pylori rendered it MtzS; and (iii) replacement of rdxA in MtzS H. pylori with an rdxA::camR null insertion allele resulted in a MtzR phenotype. The 630 bp rdxA genes of five pairs of H. pylori isolates from infections that were mixed (MtzR/MtzS), but uniform in overall genotype, were sequenced. In each case, the paired rdxA genes differed from one another by one to three base substitutions. Typical rdxA genes from unrelated isolates differ by 5% in DNA sequence. Therefore, the near identity of rdxA genes from paired MtzR and MtzS isolates implicates de novo mutation, rather than horizontal gene transfer in the development of MtzR. Horizontal gene transfer could readily be demonstrated under laboratory conditions with mutant rdxA alleles. RdxA is a homologue of the classical nitroreductases (CNRs) of the enteric bacteria, but differs in cysteine content (6 vs. 1 or 2 in CNRs) and isoelectric point (pI=7.99 vs. 5.4-5.6), which might account for its reduction of low redox drugs such as Mtz. We suggest that many rdxA (MtzR) mutations may have been selected by prior use of Mtz against other infections. H. pylori itself is an early risk factor for gastric cancer; the possibility that its carcinogenic effects are exacerbated by Mtz use, which is frequent in many societies, or the reduction of nitroaromatic compounds to toxic, mutagenic and carcinogenic products, may be of significant concern in public health.
TL;DR: Mean d2 provides a better measure of individual genetic variability than heterozygosity for microsatellite data; and a convenient tool for assessing the effects of inbreeding and outbreeding in natural populations.
Abstract: We examined the relations between fitness-related traits of wild harbour seal (Phoca vitulina) pups with microsatellite heterozygosity, and with a measure of genomic diversity based on the mean squared distance between microsatellite alleles within an individual, mean d2. Birth weight was positively influenced by maternal age, pup sex, and either mean d2 or individual heterozygosity in separate multiple regression models. The association of birth weight with mean d2 was stronger than that with heterozygosity, however. The factors maternal age, pup sex, and mean d2 combined to account for 36.8% of the variation in birth weight, with mean d2 accounting for the greatest explanatory power (52.3% of the variance explained). Pups which survived until weaning had significantly higher mean d2 than pups which died, independent of birth weight. These effects are consistent with heterosis resulting from recent population mixing, and/or inbreeding depression in this population. Mean d2 thus provides (i) a better measure of individual genetic variability than heterozygosity for microsatellite data; and (ii) a convenient tool for assessing the effects of inbreeding and outbreeding in natural populations.
TL;DR: The results suggest that at the intakes observed in this study, the chronic ingestion of uranium in drinking water affects kidney function and that the proximal tubule, rather than the glomerulus, is the site for this interference.
TL;DR: Analyses of narrative language sample by age sub-group showed no evidence of a critical period for language development ending at adolescence, nor of a "syntactic ceiling" at MLUs corresponding to simple sentences for the Down syndrome group.
Abstract: Hypotheses that children and adolescents with Down syndrome show (a) a specific expressive language impairment, (b) a "critical period" for language acquisition, (c) a "simple sentence syntactic ceiling" in production, and (d) deficit in grammatical morphology were investigated cross-sectionally. Conversational and narrative language samples from 47 children and adolescents with Down syndrome (Trisomy 21), aged 5 to 20 years, were compared to those from 47 control children aged 2 to 6 years matched statistically for nonverbal mental age. Children with Down syndrome appear to have a specific language impairment, compared to control children, in number of different words and total words (in the first 50 utterances) and in mean length of utterance (MLU). Total utterance attempts per minute were more frequent in the Down syndrome group. Narrative samples contained more word tokens, more word types, and longer MLU than conversation samples, for both groups. Intelligibility of narratives was significantly poorer for the Down syndrome group than controls. Analyses of narrative language sample by age sub-group showed no evidence of a critical period for language development ending at adolescence, nor of a "syntactic ceiling" at MLUs corresponding to simple sentences for the Down syndrome group. Omissions of word tokens and types were more frequent in the older Down syndrome than the younger control sample, matched on MLU.
TL;DR: A novel approach to stable noise modeling is introduced based on the LePage series representation and the results obtained are useful for the prediction of noise statistics in a wide range of environments with deterministic and stochastic power propagation laws.
Abstract: This paper addresses non-Gaussian statistical modeling of interference as a superposition of a large number of small effects from terminals/scatterers distributed in the plane/volume according to a Poisson point process. This problem is relevant to multiple access communication systems without power control and radar. Assuming that the signal strength is attenuated over distance r as 1/r/m, we show that the interference/clutter could be modeled as a spherically symmetric /spl alpha/-stable noise. A novel approach to stable noise modeling is introduced based on the LePage series representation. This establishes grounds to investigate practical constraints in the system model adopted, such as the finite number of interferers and nonhomogeneous Poisson fields of interferers. In addition, the formulas derived allow us to predict noise statistics in environments with lognormal shadowing and Rayleigh fading. The results obtained are useful for the prediction of noise statistics in a wide range of environments with deterministic and stochastic power propagation laws. Computer simulations are provided to demonstrate the efficiency of the /spl alpha/-stable noise model in multiuser communication systems. The analysis presented will be important in the performance evaluation of complex communication systems and in the design of efficient interference suppression techniques.
TL;DR: Research on the acute and chronic effects of alcohol and other drugs on cognitive and physiological variables relevant to PTSD intrusion and arousal symptoms is reviewed to highlight ways in which these two sets of PTSD symptoms might be functionally interrelated with substance abuse.
TL;DR: The QOLRAD is a short and user-friendly instrument with excellent psychometric properties addressing patient concerns in gastroesophageal reflux disease (GERD) and dyspepsia and its responsiveness to change in clinical trials is currently being explored.
Abstract: OBJECTIVE To develop a disease-specific QOL instrument (QOLRAD) addressing patient concerns in gastroesophageal reflux disease (GERD) and dyspepsia. Patients. 759 male (45%) and female (55%) patients with a mean age of 48.4 years (sd 15.2) were used in the psychometric evaluation. MAIN OUTCOME MEASURES A pilot version of QOLRAD, the Gastrointestinal Symptoms Rating Scale (GSRS) and the SF-36 were completed prior to endoscopy. Items with a high ceiling effect, items measuring a different construct, i.e. with a low squared multiple correlation (R 0.80) with another item were removed. A confirmatory factor analysis was also performed. RESULTS The final questionnaire included 25 items depicting problems with emotions, vitality, sleep, eating/drinking, and physical/social functioning. The internal consistency reliability was high (alpha value overall 0.97, dimensions 0.89-94). Construct validity, i.e. the associations between similar constructs in the QOLRAD, the SF-36 and the GSRS scores was confirmed. Pain and symptom severity were markers of impaired QOL. The impact on health-related QOL was similar across the functional gastrointestinal disorders with the exception of patients with a normal endoscopy, who did slightly worse. CONCLUSION The QOLRAD is a short and user-friendly instrument with excellent psychometric properties. Its responsiveness to change in (AVMC1) clinical trials is currently being explored.
TL;DR: Testing school-aged autistic children across three different contexts demonstrated that a sizeable proportion of children with autism did not have difficulties with following another's head turn, and the ability to orient to another person's head and gaze was facilitated by increasing children's attention to environmental targets and social cues.
Abstract: Children with autism are known to have difficulties in sharing attention with others. Yet one joint attention behaviour, the ability to follow another person's head turn and gaze direction, may be achieved without necessarily sharing attention. Why, then, should autistic children have difficulties with it? In this study we examined the extent of this difficulty by testing school-aged autistic children across three different contexts; experiment, observation, and parent interview. We also tested whether the ability to orient to another person's head and gaze could be facilitated by increasing children's attention to environmental targets and social cues. Results for experiment and observation demonstrate that a sizeable proportion of children with autism did not have difficulties with following another's head turn. There was a difference between children with high and low verbal mental ages, however. Whereas children with higher mental ages (over 48 months) were able to orient spontaneously to another person's head turn, children with lower mental ages had difficulties with this response. When cues were added (pointing, language) or when feedback from targets was given, however, their performance improved. Parent interview data indicated that children with autism, whatever their mental age, began to follow head turn and gaze direction years later than typically developing children. Developments in attention and language are proposed as possible factors to account for this developmental delay.
TL;DR: Correlations between parent and child pain reports do not accurately represent the relationship between these ratings and in fact overestimate the strength of the relationship, which may contribute to inadequate pain control.
Abstract: Objective: Parents are often the primary source of information regarding their children pain in both research and clinical practice. However, parent--child agreement on pain ratings has not been well established. The objective of the present study was to examine agreement between child- and parent-rated pain following minor surgery. Setting: Tertiary care children's hospital. Participants: A total of 110 children (56.4% male) aged 7-12 years undergoing surgery and their parents. Outcome Measures: Parents and children independently rated pain intensity by using a 7-point Faces Pain Scale on the day of the child's surgery and the following 2 days. Results: Correlations (both Pearson's and intraclass correlation coefficients) indicated a highly significant relationship between child and parent ratings. However, kappa statistics indicated only poor to fair agreement beyond chance. Parents tended to underestimate their children's pain on the day of surgery and the following day, but not on the second day following surgery. When children's and parents pain ratings for each of the 3 days were collapsed into a no-pain/low-pain group or a clinically significant pain group, kappa statistics indicated fair to good agreement, Parents demonstrated low levels of sensitivity in identifying when their children were experiencing clinically significant pain. Conclusions: Correlations between parent and child pain reports do not accurately represent the relationship between these ratings and in fact overestimate the strength of the relationship. Parents' underestimation of their child's pain may contribute to inadequate pain control.
TL;DR: The present review explores the conditions under which this latter, inhibitory, effect-referred to as inhibition of return (IOR)—is revealed and those conditions underWhich it is generated and indicates where further experimental research is critical.
Abstract: Unpredictive visual transient cues have a biphasic effect on reaction times (RTs) to peripheral onset targets. At relatively short (e.g., 150-msec) cue-target stimulus onset asynchronies (SOAs), RTs to targets at cued versus uncued locations are facilitated, whereas at relatively long SOAs (e.g., beyond 300 msec), they are inhibited. The present review explores the conditions under which this latter, inhibitory, effect-referred to as inhibition of return (IOR; Posner & Cohen, 1984)—is revealed and those conditions under which it is generated. We argue that the extant literature converges on the view that IOR reflects a motor response bias that is generated by the activation of an oculomotor program to fixate the cue. However, we reveal that current conceptualizations of IOR are based on a limited sampling of possible tests of the generation and measurement of IOR and indicate where further experimental research is critical.
TL;DR: In this paper, a model of UV-influenced photosynthesis in the presence of vertical mixing is presented, which is constrained with comprehensive measurements from the Weddell-Scotia Confluence during the austral spring of 1993.
Abstract: Photosynthesis of Antarctic phytoplankton is inhibited by ambient ultraviolet (UV) radiation during incubations1,2,3,4, and the inhibition is worse in regions beneath the Antarctic ozone ‘hole’4 But to evaluate such effects, experimental results on, and existing models of, photosynthesis5,6,7 cannot be extrapolated directly to the conditions of the open waters of the Antarctic because vertical mixing of phytoplankton alters UV exposure and has significant effects on the integrated inhibition through the water column2,8,9 Here we present a model of UV-influenced photosynthesis in the presence of vertical mixing, which we constrain with comprehensive measurements from the Weddell-Scotia Confluence during the austral spring of 1993 Our calculations of photosynthesis integrated through the water column (denoted PT) show that photosynthesis is strongly inhibited by near-surface UV radiation This inhibition can be either enhanced or decreased by vertical mixing, depending on the depth of the mixed layer Predicted inhibition is most severe when mixing is rapid, extending to the lower part of the photic zone Our analysis reveals that an abrupt 50% reduction in stratospheric ozone could, in the worst case, lower PT by as much as 85% However, stronger influences on inhibition can come from realistic changes in vertical mixing (maximum effect on PT of about ±37%), measured differences in the sensitivity of phytoplankton to UV radiation (±46%) and cloudiness (±15%)
TL;DR: In this article, a simple model that accounts for the feedback between resource (food) abundance, its reactivity, and the intensity of bioturbation leads to a quantitative estimate of 9.7 cm.
Abstract: The activities and consequently the bioturbational effects of deposit-feeding organisms are largely restricted to a narrow surficial zone of marine sediments with a worldwide, environmentally invariant mean of 9.8 cm with a standard deviation of 4.5 cm. Currently available theories of infaunal behavior cannot predict quantitatively this observation. A new simple model that accounts for the feedback between resource (food) abundance, its reactivity, and the intensity of bioturbation leads to a quantitative estimate of 9.7 cm. This model constitutes a fundamental advance in our understanding bioturbation.
TL;DR: In this paper, an ab initio pseudopotential plane-wave method was used to calculate the total energies for several structures of the lithium-tin phase diagram, which were used to determine a theoretical electrochemical voltage profile, which compares well with experiment for $xl2.5$ in the room-temperature electrochemical cell.
Abstract: An ab initio pseudopotential plane-wave method was used to calculate the total energies for several structures (Sn, ${\mathrm{Li}}_{2}{\mathrm{Sn}}_{5},$ LiSn, ${\mathrm{Li}}_{7}{\mathrm{Sn}}_{3},$ ${\mathrm{Li}}_{5}{\mathrm{Sn}}_{2},$ ${\mathrm{Li}}_{13}{\mathrm{Sn}}_{5},$ ${\mathrm{Li}}_{7}{\mathrm{Sn}}_{2},$ and Li) of the lithium-tin phase diagram. This information was used to determine a theoretical electrochemical voltage profile, which compares well with experiment for $xl2.5$ in ${\mathrm{Li}}_{x}\mathrm{Sn}.$ For $xg2.5,$ it was found that the equilibrium structures predicted by the phase diagram were not formed in the room-temperature electrochemical cell, which explains why the calculated results are less good there. Calculations of this type are useful for materials research in lithium-ion batteries.
TL;DR: The PCQ is a promising instrument for assessing children's pain coping strategies and can be administered to children as young as 8 years of age in approximately 15 min, making it useful for assessing coping across a wide age range.
Abstract: A new measure of coping, the Pain Coping Questionnaire (PCQ), is presented and validated in two studies of children and adolescents. Factor analyses of data from healthy children and adolescents supported eight hypothesized subscales (information seeking, problem solving, seeking social support, positive self-statements, behavioral distraction, cognitive distraction, externalizing, internalizing/catastrophizing) and three higher-order scales (approach, problem-focused avoidance, emotion-focused avoidance). The subscales and higher-order scales were internally consistent. The pain coping scales were correlated in the expected directions with children's appraisals of pain controllability, self-rated coping effectiveness, emotional distress when in pain, and among high school students, pain thresholds and functional disability. The structure and internal consistency of the PCQ were replicated in a sample of children and adolescents experiencing recurrent pain (headache, arthritis), and their parents. Relations between child- and parent-ratings of children's coping were moderate (median r=0.34). Higher levels of emotion-focused avoidance were related to more emotional distress (both samples), less coping effectiveness (headache sample), and higher levels of pain (arthritis sample). Higher levels of approach coping were related to less disability (headache sample). Other relations between approach and distraction coping and the outcome variables were generally not significant. The PCQ is a promising instrument for assessing children's pain coping strategies. The items are simple and relatively few, making it useful for assessing coping across a wide age range. It can be administered to children as young as 8 years of age in approximately 15 min.
TL;DR: Mitochondria in cells without trophic support underwent a progressive shift to lower ΔΨM values that was significant by 3 hr after washing, and (−)-Deprenyl appeared to alter the relationship between intramitochondrial Ca2+ levels and ΔΩM, possibly through its reported capacity to increase the synthesis of proteins such as BCL-2.
Abstract: Studies in non-neural cells have suggested that a fall in mitochondrial membrane potential (ΔΨM) is one of the earliest events in apoptosis. It is not known whether neural apoptosis caused by nerve growth factor (NGF) and serum withdrawal involves a decrease in ΔΨM. We used epifluorescence and laser confocal microscopy with the mitochondrial potentiometric dyes chloromethyl-tetramethylrosamine methyl ester and 5,5′,6,6′-tetrachloro-1,1′,3,3′-tetraethybenzimidazol carbocyanine iodide to estimate ΔΨM. PC12 cells were differentiated in media containing serum and NGF for 6 d before withdrawal of trophic support. After washing, the cells were incubated with media containing serum and NGF (M/S+N), media without serum and NGF, or media with the “trophic-like” monoamine oxidase B inhibitor, (−)-deprenyl. Mitochondria in cells without trophic support underwent a progressive shift to lower ΔΨM values that was significant by 3 hr after washing. The percentages of cells with nuclear chromatin condensation or nuclear DNA fragmentation were not significantly increased above those for cells in M/S+N until 6 hr after washing. Replacement of cells into M/S+N or treatment with (−)-deprenyl markedly reduced the proportion of mitochondria with decreased ΔΨM. Measurements of cytoplasmic peroxyl radical levels with 2′,7′-dihydrodichlorofluorescein fluorescence and intramitochondrial Ca2+ with dihydro-rhodamine-2-acetylmethyl ester indicated that cytoplasmic peroxyl radical levels were not increased until after 6 hr, whereas increases in intramitochondrial Ca2+ paralleled the decreases in ΔΨM. (−)-Deprenyl appeared to alter the relationship between intramitochondrial Ca2+ levels and ΔΨM, possibly through its reported capacity to increase the synthesis of proteins such as BCL-2.
TL;DR: This review discusses in detail the structural features of the RING and B-box domains and possible structure function relationships for these motifs particularly in their role as protein interaction domains.
Abstract: The cysteine-rich zinc-binding motifs known as the RING and B-box are found in several unrelated proteins Structural, biochemical, and biological studies of these motifs reveal that they mediate p