Showing papers by "Dalhousie University published in 2006"

Impacts of biodiversity loss on ocean ecosystem services.

Abstract: Human-dominated marine ecosystems are experiencing accelerating loss of populations and species, with largely unknown consequences. We analyzed local experiments, long-term regional time series, and global fisheries data to test how biodiversity loss affects marine ecosystem services across temporal and spatial scales. Overall, rates of resource collapse increased and recovery potential, stability, and water quality decreased exponentially with declining diversity. Restoration of biodiversity, in contrast, increased productivity fourfold and decreased variability by 21%, on average. We conclude that marine biodiversity loss is increasingly impairing the ocean's capacity to provide food, maintain water quality, and recover from perturbations. Yet available data suggest that at this point, these trends are still reversible.

Depletion, Degradation, and Recovery Potential of Estuaries and Coastal Seas

Abstract: Estuarine and coastal transformation is as old as civilization yet has dramatically accelerated over the past 150 to 300 years. Reconstructed time lines, causes, and consequences of change in 12 once diverse and productive estuaries and coastal seas worldwide show similar patterns: Human impacts have depleted >90% of formerly important species, destroyed >65% of seagrass and wetland habitat, degraded water quality, and accelerated species invasions. Twentieth-century conservation efforts achieved partial recovery of upper trophic levels but have so far failed to restore former ecosystem structure and function. Our results provide detailed historical baselines and quantitative targets for ecosystem-based management and marine conservation.

Resilience across Cultures

Abstract: Summary Findings from a 14 site mixed methods study of over 1500 youth globally support four propositions that underlie a more culturally and contextually embedded understanding of resilience: 1) there are global, as well as culturally and contextually specific aspects to young people’s lives that contribute to their resilience; 2) aspects of resilience exert differing amounts of influence on a child’s life depending on the specific culture and context in which resilience is realized; 3) aspects of children’s lives that contribute to resilience are related to one another in patterns that reflect a child’s culture and context; 4) tensions between individuals and their cultures and contexts are resolved in ways that reflect highly specific relationships between aspects of resilience. The implications of this cultural and contextual understanding of resilience to interventions with at-risk populations are discussed.

A systematic review of faculty development initiatives designed to improve teaching effectiveness in medical education: BEME Guide No. 8.

Abstract: Background: Preparing healthcare professionals for teaching is regarded as essential to enhancing teaching effectiveness. Although many reports describe various faculty development interventions, there is a paucity of research demonstrating their effectiveness.Objective: To synthesize the existing evidence that addresses the question: “What are the effects of faculty development interventions on the knowledge, attitudes and skills of teachers in medical education, and on the institutions in which they work?”Methods: The search, covering the period 1980–2002, included three databases (Medline, ERIC and EMBASE) and used the keywords: staff development; in-service training; medical faculty; faculty training/development; continuing medical education. Manual searches were also conducted.Articles with a focus on faculty development to improve teaching effectiveness, targeting basic and clinical scientists, were reviewed. All study designs that included outcome data beyond participant satisfaction were accepted....

A systematic review of faculty development initiatives designed to improve teaching effectiveness in medical education: BEME Guide No. 8

Abstract: Background: Preparing healthcare professionals for teaching is regarded as essential to enhancing teaching effectiveness. Although many reports describe various faculty development interventions, there is a paucity of research demonstrating their effectiveness.Objective: To synthesize the existing evidence that addresses the question: “What are the effects of faculty development interventions on the knowledge, attitudes and skills of teachers in medical education, and on the institutions in which they work?”Methods: The search, covering the period 1980–2002, included three databases (Medline, ERIC and EMBASE) and used the keywords: staff development; in-service training; medical faculty; faculty training/development; continuing medical education. Manual searches were also conducted.Articles with a focus on faculty development to improve teaching effectiveness, targeting basic and clinical scientists, were reviewed. All study designs that included outcome data beyond participant satisfaction were accepted....

Validity and reliability of the Edmonton Frail Scale

Abstract: 1. Meltzer H, Gill H, Petticrew M, Hinds K. Office of Population Census and Surveys (OPCS)—Surveys of Psychiatric Morbidity in Great Britain Report 1: The prevalence of psychiatric morbidity amongst adults living in private households. London: HMSO, 1995. 2. Beekman AT, Copeland JR, Prince MJ. Review of community prevalence of depression in later life. Br J Psychiatry 1999; 174: 307–11. 3. Prescription Pricing Authority (PPA) PACT Centre Pages. Drugs used in Mental Health. http://www.ppa.org.uk/news/ pact-112003/pact-112003.htm (4 November 2004, date last accessed). 4. Middleton N, Gunnell D, Whitley E, Dorling D, Frankel S. Secular trends in antidepressant prescribing in the UK, 1975–1998 J Public Health Med 2001; 23: 262–6. 5. National Institute for Clinical Excellence. Management of depression in primary and secondary care. Clinical Guideline 23. National Institute for Clinical Excellence 2004. 6. Percudani M, Barbui C, Fortino I, Petrovich L. Antidepressant drug prescribing among elderly subjects: a population-based study. Int J Geriatr Psychiatry 2005; 20: 113–8. 7. Lawreson RA, Tyrere F, Newson RB, Farmer RDT. The treatment of depression in UK general practice: selective serotonin reuptake inhibitors and tricyclic antidepressants compared. J Affect Disord 2000; 59: 149–57. 8. Wilson KC, Copeland JR, Taylor S, Donoghue J, McCracken CF. Natural history of pharmacotherapy of older depressed community resident. The MRC-ALPHA Study. Br J Psychiatry 1999; 175: 439–43. 9. Living in Britain. A summary of changes over time – Use of health services. Office of National Statistics (ONS). http://www.statistics.gov.uk (16 February 2005, date last accessed). 10. Rosenbaum JF, Zajecka J. Clinical management of antidepressant discontinuation. J Clin Psychiatry 1998; 59: 535–7. 11. Zermansky AG. Who controls repeats? Br J Gen Prac 1996; 46: 643–7.

Mortality in systemic lupus erythematosus.

Abstract: Objective. To examine mortality rates in the largest systemic lupus erythematosus (SLE) cohort ever assembled. Methods. Our sample was a multisite international SLE cohort (23 centers, 9,547 patients). Deaths were ascertained by vital statistics registry linkage. Standardized mortality ratio (SMR; ratio of deaths observed to deaths expected) estimates were calculated for-all deaths and by cause. The effects of sex, age, SLE duration, race, and calendar-year periods were determined. Results. The overall SMR was 2.4 (95% confidence interval 2.3-2.5). Particularly high mortality was seen for circulatory disease, infections, renal disease, non-Hodgkin's lymphoma, and lung cancer. The highest SMR estimates were seen in patient groups characterized by female sex, younger age, SLE duration < 1 year, or black/African American race. There was a dramatic decrease in total SMR estimates across calendar-year periods, which was demonstrable for specific causes including death due to infections and death due to renal disorders. However, the SMR due to circulatory diseases tended to increase slightly from the 1970s to the year 2001. Conclusion. Our data from a very large multicenter international cohort emphasize what has been demonstrated previously in smaller samples. These results highlight the increased mortality rate in SLE patients compared with the general population, and they suggest particular risk associated with female sex, younger age, shorter SLE duration, and black/African American race. The risk for certain types of deaths, primarily related to lupus activity (such as renal disease), has decreased over time, while the risk for deaths due to circulatory disease does not appear to have diminished. (Less)

Buried alive: how osteoblasts become osteocytes.

Abstract: During osteogenesis, osteoblasts lay down osteoid and transform into osteocytes embedded in mineralized bone matrix. Despite the fact that osteocytes are the most abundant cellular component of bone, little is known about the process of osteoblast-to-osteocyte transformation. What is known is that osteoblasts undergo a number of changes during this transformation, yet retain their connections to preosteoblasts and osteocytes. This review explores the osteoblast-to-osteocyte transformation during intramembranous ossification from both morphological and molecular perspectives. We investigate how these data support five schemes that describe how an osteoblast could become entrapped in the bone matrix (in mammals) and suggest one of the five scenarios that best fits as a model. Those osteoblasts on the bone surface that are destined for burial and destined to become osteocytes slow down matrix production compared to neighbouring osteoblasts, which continue to produce bone matrix. That is, cells that continue to produce matrix actively bury cells producing less or no new bone matrix (passive burial). We summarize which morphological and molecular changes could be used as characters (or markers) to follow the transformation process.

Predictors of parent training efficacy for child externalizing behavior problems--a meta-analytic review.

Abstract: Background: The differential effectiveness of parent training has led researchers to examine a variety of child, parent, and familial variables that may predict treatment response. Studies have identified a diverse set of child, parent psychological/behavioral and demographic variables that are associated with treatment outcome and dropout. Method: The parent training literature was examined to isolate child, parent, and family variables that predict response to parent training for child externalizing behavior problems. A literature review was conducted spanning articles published from 1980 to 2004 of indicated prevention (children with symptoms) and treatment (children with diagnosis) studies. Meta-analyses were conducted to determine standardized effect sizes associated with the identified predictors. Results: Many of the predictors of treatment response examined in this meta-analysis resulted in moderate standardized effect sizes when study results were subjected to meta-analytic procedures (i.e., low education/occupation, more severe child behavior problems pretreatment, maternal psychopathology). Only low family income resulted in a large standardized effect size. Predictors of drop-out resulted in standardized effect sizes in the small or insubstantial range. Conclusions: Response to parent training is often influenced by variables not directly involving the child, with socioeconomic status and maternal mental health being particularly salient factors.

Globalization, Roving Bandits, and Marine Resources

Abstract: Marine resource exploitation can deplete stocks faster than regulatory agencies can respond. Institutions with broad authority and a global perspective are needed to create a system with incentives for conservation.

Width and Thickness of Fluvial Channel Bodies and Valley Fills in the Geological Record: A Literature Compilation and Classification

Abstract: The three-dimensional geometry of fluvial channel bodies and valley fills has received much less attention than their internal structure, despite the fact that many subsurface analyses draw upon the geometry of suitable fluvial analogues. Although channel-body geometry has been widely linked to base-level change and accommodation, few studies have evaluated the influence of local geomorphic controls. To remedy these deficiencies, we review the terminology for describing channel-body geometry, and present a literature dataset that represents more than 1500 bedrock and Quaternary fluvial bodies for which width (W) and thickness (T) are recorded. Twelve types of channel bodies and valley fills are distinguished based on their geomorphic setting, geometry, and internal structure, and log-log plots of W against T are presented for each type. Narrow and broad ribbons (W/T 1000, respectively) are distinguished. The dataset allows an informed selection of analogues for subsurface applications, and spreadsheets and graphs can be downloaded from a data repository. Mobile-channel belts are mainly the deposits of braided and low-sinuosity rivers, which may exceed 1 km in composite thickness and 1300 km in width. Their overwhelming dominance throughout geological time reflects their link to tectonic activity, exhumation events, and high sediment supply. Some deposits that rest on flat-lying bedrock unconformities cover areas > 70,000 km2. In contrast, meandering river bodies in the dataset are < 38 m thick and < 15 km wide, and the organized flow conditions necessary for their development may have been unusual. They do not appear to have built basin-scale deposits. Fixed channels and poorly channelized systems are divided into distributary systems (channels on megafans, deltas, and distal alluvial fans, and in crevasse systems and avulsion deposits), through-going rivers, and channels in eolian settings. Because width/maximum depth of many modern alluvial channels is between 5 and 15, these bodies probably record an initial aspect ratio followed by modest widening prior to filling or avulsion. The narrow form (W/T typically < 15) commonly reflects bank resistance and rapid filling, although some are associated with base-level rise. Exceptionally narrow bodies (W/T locally < 1) may additionally reflect unusually deep incision, compactional thickening, filling by mass-flow deposits, balanced aggradation of natural levees and channels, thawing of frozen substrates, and channel reoccupation. Valley fills rest on older bedrock or represent a brief hiatus within marine and alluvial successions. Many bedrock valley fills have W/T < 20 due to deep incision along tectonic lineaments and stacking along faults. Within marine and alluvial strata, upper Paleozoic valley fills appear larger than Mesozoic examples, possibly reflecting the influence of large glacioeustatic fluctuations in the Paleozoic. Valley fills in sub-glacial and proglacial settings are relatively narrow (W/T as low as 2.5) due to incision from catastrophic meltwater flows. The overlap in dimensions between channel bodies and valley fills, as identified by the original authors, suggests that many braided and meandering channel bodies in the rock record occupy paleovalleys. Modeling has emphasized the importance of avulsion frequency, sedimentation rate, and the ratio of channel belt and floodplain width in determining channel-body connectedness. Although these controls strongly influence mobile channel belts, they are less effective in fixed-channel systems, for which many database examples testify to the influence of local geomorphic factors that include bank strength and channel aggradation. The dataset contains few examples of highly connected suites of fixed-channel bodies, despite their abundance in many formations. Whereas accommodation is paramount for preservation, its influence is mediated through geomorphic factors, thus complicating inferences about base-level controls.

Decline in Relative Abundance of Bottlenose Dolphins Exposed to Long-Term Disturbance

Abstract: Studies evaluating effects of human activity on wildlife typically emphasize short-term behavioral responses from which it is difficult to infer biological significance or formulate plans to mitigate harmful impacts. Based on decades of detailed behavioral records, we evaluated long-term impacts of vessel activity on bottlenose dolphins (Tursiops sp.) in Shark Bay, Australia. We compared dolphin abundance within adjacent 36- km 2 tourism and control sites, over three consecutive 4.5-year periods wherein research activity was relatively constant but tourism levels increased from zero, to one, to two dolphin-watching operators. A nonlinear logistic model demonstrated that there was no difference in dolphin abundance between periods with no tourism and periods in which one operator offered tours. As the number of tour operators increased to two, there was a significant average decline in dolphin abundance (14.9%; 95% CI =− 20.8 to −8.23), approximating a decline of one per seven individuals. Concurrently, within the control site, the average increase in dolphin abundance was not significant (8.5%; 95% CI =− 4.0 to +16.7). Given the substantially greater presence and proximity of tour vessels to dolphins relative to research vessels, tour-vessel activity contributed more to declining dolphin numbers within the tourism site than research vessels. Although this trend may not jeopardize the large, genetically diverse dolphin population of Shark Bay, the decline is unlikely to be sustainable for local dolphin tourism. A similar decline would be devastating for small, closed, resident, or endangered cetacean populations. The substantial effect of tour vessels on dolphin abundance in a region of low-level tourism calls into question the presumption that dolphin-watching tourism is benign.

The Development of Physical Aggression from Toddlerhood to Pre-Adolescence: A Nation Wide Longitudinal Study of Canadian Children

Abstract: The objectives of the study were to model the developmental trajectories of physical aggression (PA) from toddlerhood to pre-adolescence and to identify risk factors that distinguish typical (normative) from atypical developmental patterns. Ten cohorts of approximately 1,000 children (n = 10,658) drawn form a nationally representative (Canadian) sample were followed over 6 years. Using a group based trajectory approach, we identified three groups of children with distinct developmental trajectories between 2 and 11 years of age. One third of the children (31.1%) followed a low desisting trajectory, reflected in infrequent use of PA in toddlerhood and virtually no PA by pre-adolescence. The majority of children (52.2%) followed a moderate desisting trajectory, reflected in occasional use of PA in toddlerhood and infrequent use by pre-adolescence. One sixth of the children (16.6%) followed a high stable trajectory of PA. Multivariate logistic regression indicated that children in the high PA trajectory group were more likely to be boys (OR: 1.67; CI: 1.5–1.87), from low income families (OR: 1.4; CI; 1.27–1.67), from families where the mother had not completed high school (OR: 1.20; CI: 1.05–1.38) and who reported using hostile/ineffective parenting strategies (OR: 1.16; CI: 1.14–1.18). In sum, the results indicate that the typical developmental pattern of PA was one of occasional and declining use over time. However, about one sixth of children, mostly boys from disadvantaged families, exhibited an atypical developmental pattern reflected in more frequent and stable use of PA. The results suggest that most children learned relatively well to inhibit PA by the end of childhood and that a minority failed to do so. Family risks traditionally found to be associated with antisocial behaviors during adolescence appear to interfere with the socialization of PA during early and middle childhood.

Studying trophic ecology in marine ecosystems using fatty acids: a primer on analysis and interpretation

Abstract: Fatty acids (FA) represent a large group of molecules that comprise the majority of lipids found in all organisms. Their great diversity, biochemical restrictions and, in some cases, unique origin among plants and animals has fostered a number of areas of research, ranging from assessment of animal nutrition and metabolism, to investigating trophic interactions and ecosystem structure. Over the past three decades, we have observed the use of FA develop from a potential tool for delineating food webs (Ackman and Eaton 1966) to a powerful technique for quantitative assessment of predator diets (Iverson et al. 2004). Studies that have compared the FA found in predator fat stores with those found in their prey have allowed both qualitative (e.g., Horgan and Barrett 1985; Smith et al. 1996; Raclot et al. 1998; Dahl et al. 2000, 2003; Falk-Petersen et al. 2004) and quantitative or semi-quantitative analyses of diet (Kirsch et al. 2000; Iverson et al. 2001b, 2004; Iverson and Springer 2002) and

Digital in-line holographic microscopy.

Abstract: We first briefly review the state of the art of digital in-line holographic microscopy (DIHM) with numerical reconstruction and then discuss some technical issues, such as lateral and depth resolution, depth of field, twin image, four-dimensional tracking, and reconstruction algorithm. We then present a host of examples from microfluidics and biology of tracking the motion of spheres, algae, and bacteria. Finally, we introduce an underwater version of DIHM that is suitable for in situ studies in an ocean environment that show the motion of various plankton species.

Residential cogeneration systems: Review of the current technology

Abstract: There is a growing potential for the use of micro-cogeneration systems in the residential sector because they have the ability to produce both useful thermal energy and electricity from a single source of fuel such as oil or natural gas. In cogeneration systems, the efficiency of energy conversion increases to over 80% as compared to an average of 30–35% for conventional fossil fuel fired electricity generation systems. This increase in energy efficiency can result in lower costs and reduction in greenhouse gas emissions when compared to the conventional methods of generating heat and electricity separately. Cogeneration systems and equipment suitable for residential and small-scale commercial applications like hospitals, hotels or institutional buildings are available, and many new systems are under development. These products are used or aimed for meeting the electrical and thermal demands of a building for space and domestic hot water heating, and potentially, absorption cooling. The aim of this paper is to provide an up-to-date review of the various cogeneration technologies suitable for residential applications. The paper considers the various technologies available and under development for residential, i.e. single-family (

Using psychophysiological techniques to measure user experience with entertainment technologies

Abstract: Emerging technologies offer exciting new ways of using entertainment technology to create fantastic play experiences and foster interactions between players. Evaluating entertainment technology is challenging because success isn't defined in terms of productivity and performance, but in terms of enjoyment and interaction. Current subjective methods of evaluating entertainment technology aren't sufficiently robust. This paper describes two experiments designed to test the efficacy of physiological measures as evaluators of user experience with entertainment technologies. We found evidence that there is a different physiological response in the body when playing against a computer versus playing against a friend. These physiological results are mirrored in the subjective reports provided by the participants. In addition, we provide guidelines for collecting physiological data for user experience analysis, which were informed by our empirical investigations. This research provides an initial step towards usi...

American Society of Clinical Oncology 2006 Update of the Breast Cancer Follow-Up and Management Guidelines in the Adjuvant Setting

Abstract: Purpose To update the 1999 American Society of Clinical Oncology (ASCO) guideline on breast cancer follow-up and management in the adjuvant setting. Methods An ASCO Expert Panel reviewed pertinent information from the literature through March 2006. More weight was given to studies that tested a hypothesis directly relating testing to one of the primary outcomes in a randomized design. Results The evidence supports regular history, physical examination, and mammography as the cornerstone of appropriate breast cancer follow-up. All patients should have a careful history and physical examination performed by a physician experienced in the surveillance of cancer patients and in breast examination. Examinations should be performed every 3 to 6 months for the first 3 years, every 6 to 12 months for years 4 and 5, and annually thereafter. For those who have undergone breast-conserving surgery, a post-treatment mammogram should be obtained 1 year after the initial mammogram and at least 6 months after completion ...

Environmental influences on aquatic plants in freshwater ecosystems

Abstract: Aquatic plants are important components of many freshwater ecosystems. In this review we examine natural and anthropogenic influences on the distribution and abundance of aquatic plants, and develo...

Differences between Tissue-Associated Intestinal Microfloras of Patients with Crohn's Disease and Ulcerative Colitis

Abstract: A leading hypothesis for the role of bacteria in inflammatory bowel diseases is that an imbalance in normal gut flora is a prerequisite for inflammation. Testing this hypothesis requires comparisons between the microbiota compositions of ulcerative colitis and Crohn's disease patients and those of healthy individuals. In this study, we obtained biopsy samples from patients with Crohn's disease and ulcerative colitis and from healthy controls. Bacterial DNA was extracted from the tissue samples, amplified using universal bacterial 16S rRNA gene primers, and cloned into a plasmid vector. Insert-containing colonies were picked for high-throughput sequencing, and sequence data were analyzed, yielding species-level phylogenetic data. The clone libraries yielded 3,305 sequenced clones, representing 151 operational taxonomical units. There was no significant difference between floras from inflamed and healthy tissues from within the same individual. Proteobacteria were significantly (P = 0.0007) increased in Crohn's disease patients, as were Bacteroidetes (P < 0.0001), while Clostridia were decreased in that group (P < 0.0001) in comparison with the healthy and ulcerative colitis groups, which displayed no significant differences. Thus, the bacterial flora composition of Crohn's patients appears to be significantly altered from that of healthy controls, unlike that of ulcerative colitis patients. Imbalance in flora in Crohn's disease is probably not sufficient to cause inflammation, since microbiotas from inflamed and noninflamed tissues were of similar compositions within the same individual.

Clinical response to adalimumab treatment in patients with moderate to severe psoriasis: double-blind, randomized controlled trial and open-label extension study

Abstract: Background Tumor necrosis factor is pivotal in the pathogenesis of psoriasis. Adalimumab is a fully human monoclonal immunoglobulin G 1 antibody that neutralizes tumor necrosis factor. Objectives We sought to assess the efficacy and safety of adalimumab in patients with moderate to severe plaque psoriasis. Methods In this multicenter, randomized, double-blind, placebo-controlled study, 147 patients received adalimumab (40 mg every other week or 40 mg/wk) or placebo. After 12 weeks of blinded therapy, patients taking adalimumab could continue their assigned dosages in a 48-week extension trial; patients taking placebo were switched to adalimumab (40 mg every other week). Results At week 12, 53% of patients taking adalimumab every other week, 80% of patients taking adalimumab weekly, and 4% of patients taking placebo achieved 75% improvement in Psoriasis Area and Severity Index score ( P Limitations The study was insufficiently powered to detect rare adverse events associated with adalimumab. Conclusions Adalimumab significantly improved psoriasis and was well tolerated for 60 weeks.

Randomized Trial of Long-Term Follow-Up for Early-Stage Breast Cancer: A Comparison of Family Physician Versus Specialist Care

Abstract: Purpose Most women with breast cancer are diagnosed at an early stage and more than 80% will be long-term survivors. Routine follow-up marks the transition from intensive treatment to survivorship. It is usual practice for routine follow-up to take place in specialist clinics. This study tested the hypothesis that follow-up by the patient’s family physician is a safe and acceptable alternative to specialist follow-up. Patients and Methods A multicenter, randomized, controlled trial was conducted involving 968 patients with early-stage breast cancer who had completed adjuvant treatment, were disease free, and were between 9 and 15 months after diagnosis. Patients may have continued receiving adjuvant hormonal therapy. Patients were randomly allocated to follow-up in the cancer center according to usual practice (CC group) or follow-up from their own family physician (FP group). The primary outcome was the rate of recurrence-related serious clinical events (SCEs). The secondary outcome was health-related quality of life (HRQL). Results In the FP group, there were 54 recurrences (11.2%) and 29 deaths (6.0%). In the CC group, there were 64 recurrences (13.2%) and 30 deaths (6.2%). In the FP group, 17 patients (3.5%) compared with 18 patients (3.7%) in the CC group experienced an SCE (0.19% difference; 95% CI, 2.26% to 2.65%). No statistically significant differences (P .05) were detected between groups on any of the HRQL questionnaires. Conclusion Breast cancer patients can be offered follow-up by their family physician without concern that important recurrence-related SCEs will occur more frequently or that HRQL will be negatively affected. J Clin Oncol 24:848-855. © 2006 by American Society of Clinical Oncology

Early language and communication development of infants later diagnosed with autism spectrum disorder.

Abstract: It is well recognized that delayed ''first words'' is among the most common presenting symptoms of autistic spectrum disorders (ASD). However, data on earlier language and communication development in children with ASD are limited to retrospective reports from parents and from home videos. In this study, we prospectively collected parent report data on early communication and language development in 97 infant siblings of children with ASD and 49 low-risk controls. Parents completed the MacArthur Communicative Development InventoryYInfant Form at 12 and 18 months. Analysis compared 3 groups defined on the basis of diagnostic assessment at 24 months: (1) siblings with ASD (n = 15), (2) siblings not meeting diagnostic criteria for ASD (n = 82), and (3) low-risk controls, none of whom had ASD (n = 49). Children with ASD showed delays in early language and communication compared with non-ASD siblings and controls. At 12 months, the ASD group was reported to understand significantly fewer phrases and to produce fewer gestures. At 18 months, they showed delays in their understanding of phrases, comprehension and production of single words, and use of gestures. Siblings not diagnosed with ASD also used fewer play-related gestures at 18 months than low-risk controls, even when children with identified language delays were excluded. Overall, this prospective study confirms that delays in communication and language development are apparent early in life in children with ASD, and emphasizes that developmental surveillance should include monitoring for delays in gesture, which may be among the earliest signs of ASD. J Dev Behav Pediatr 27:69Y78, 2006. Index terms: autism, language, communication, gestures, infant behavior. The developmental challenges associated with autism arise from a unique constellation of features spanning social communication and language, and behavioral adaptation. The predominant features of autism-related developmental disorders (referred to collectively as the autistic spectrum of disorders; ASD) include qualitative impairments in both verbal and nonverbal communication. 1 In addition, receptive and expres-

Estimating ground-level PM2.5 using aerosol optical depth determined from satellite remote sensing

Abstract: [1] We assess the relationship of ground-level fine particulate matter (PM 2.5 ) concentrations for 2000-2001 measured as part of the Canadian National Air Pollution Surveillance (NAPS) network and the U.S. Air Quality System (AQS), versus remote-sensed PM 2.5 determined from aerosol optical depths (AOD) measured by the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Multiangle Imaging Spectroradiometer (MISR) satellite instruments. A global chemical transport model (GEOS-CHEM) is used to simulate the factors affecting the relation between AOD and PM 2.5 . AERONET AOD is used to evaluate the method (r = 0.71, N = 48, slope = 0.69). We find significant spatial variation of the annual mean ground-based measurements with PM 2.5 determined from MODIS (r = 0.69, N = 199, slope = 0.82) and MISR (r = 0.58, N = 199, slope = 0.57). Excluding California significantly increases the respective slopes and correlations. The relative vertical profile of aerosol extinction is the most important factor affecting the spatial relationship between satellite and surface measurements of PM 2.5 ; neglecting this parameter would reduce the spatial correlation to 0.36. In contrast, temporal variation in AOD is the most influential parameter affecting the temporal relationship between satellite and surface measurements of PM 2.5 ; neglecting daily variation in this parameter would decrease the correlation in eastern North America from 0.5-0.8 to less than 0.2. Other simulated aerosol properties, such as effective radius and extinction efficiency have a minor role temporally, but do influence the spatial correlation. Global mapping of PM 2.5 from both MODIS and MISR reveals annual mean concentrations of 40-50 ug/m 3 over northern India and China.

Long-term risks of death and institutionalization of elderly people in relation to deficit accumulation at age 70

Abstract: OBJECTIVES: To measure relative fitness and frailty in older people without specific frailty instruments and to relate that measurement to long-term health outcomes. DESIGN: Retrospective cohort studies. SETTING: Two population-based studies of people aged approximately 70 at baseline and followed up to 10 years (in the Canadian Study of Health and Aging (CSHA)) or 26 years in the Gothenburg H-70 cohort study. PARTICIPANTS: Nine hundred sixty-two men and 1,178 women. MEASUREMENTS: Deficit accumulation (the exposure) was counted using self-reported (CSHA) or clinically designated (H-70) symptoms, signs, diseases, and disabilities. Relative fitness and frailty were measured in relation to the degree of deficit accumulation evaluated in four quartiles, representing those most fit to those most frail. The items that made up the frailty index were selected randomly without replacement in 1,000 iterations. The outcomes were risks of death or residential long-term care. RESULTS: Worse frailty, however measured, was associated with worse survival; the Kaplan-Meier curves of random iterations of the frailty definition showed virtually no interquartile overlap for mortality. For any given level of frailty, men died younger than women. Worse frailty was also associated with a higher risk of institutionalization. CONCLUSION: Frailty appears to be a robust concept that is readily operationalized, with the risk of adverse outcomes being largely established by age 70.

Channel flow, ductile extrusion and exhumation in continental collision zones: an introduction

Abstract: The channel flow model aims to explain features common to metamorphic hinterlands of some collisional orogens, notably along the Himalaya–Tibet system. Channel flow describes a protracted flow of a weak, viscous crustal layer between relatively rigid yet deformable bounding crustal slabs. Once a critical low viscosity is attained (due to partial melting), the weak layer flows laterally due to a horizontal gradient in lithostatic pressure. In the Himalaya–Tibet system, this lithostatic pressure gradient is created by the high crustal thicknesses beneath the Tibetan Plateau and ‘normal’ crustal thickness in the foreland. Focused denudation can result in exhumation of the channel material within a narrow, nearly symmetric zone. If channel flow is operating at the same time as focused denudation, this can result in extrusion of the mid-crust between an upper normal-sense boundary and a lower thrust-sense boundary. The bounding shear zones of the extruding channel may have opposite shear sense; the sole shear zone is always a thrust, while the roof shear zone may display normal or thrust sense, depending on the relative velocity between the upper crust and the underlying extruding material. This introductory chapter addresses the historical, theoretical, geological and modelling aspects of channel flow, emphasizing its applicability to the Himalaya–Tibet orogen. Critical tests for channel flow in the Himalaya, and possible applications to other orogenic belts, are also presented. The hinterlands of collisional orogens are often characterized by highly strained, high-grade metamorphic rocks that commonly display features consistent with lateral crustal flow and extrusion of material from mid-crustal depths towards the orogenic foreland. A recent model for lateral flow of such weak mid-crustal layers has become widely known as the ‘channel flow’ model. The channel flow model has matured through efforts by several research groups and has also been applied to a variety of geodynamic settings. Thermal-mechanical modelling of collision zones, including the Himalayan–Tibetan system, has brought the concept of channel flow to the forefront of orogenic studies. Original contributors to the concept of channel flow initiated an important paradigm shift (Kuhn 1979), from geodynamic models of continental crust with finite rheological layering to the more encompassing channel flow model. This time-dependent midto lower crustal flow process, which will be reviewed in this chapter, may progress into foreland fold-and-thrust tectonics in the upper crust, thereby providing a spatial and temporal link between the early development of a metamorphic core in the hinterland and the foreland fold-and-thrust belt at shallower structural levels. Outcomes and implications of such a viscous flowing middle to lower crust include a dynamic coupling between mid-crustal and surface processes, and limitations to accurate retro-deformation of orogens (non-restorable orogens, e.g. Jamieson et al. 2006). This Special Publication contains a selection of papers that were presented at the conference ‘Channel flow, extrusion, and exhumation of lower to mid-crust in continental collision zones’ hosted by the Geological Society of London at Burlington House, in December 2004. Because most of the ongoing debate on crustal flow focuses on the Cenozoic age Himalaya–Tibet collisional system, some of the key questions that are addressed in this volume include the following. . Does the model for channel flow in the Himalaya–Tibet system concur with all available geological and geochronological data? From: LAW, R. D., SEARLE, M. P. & GODIN, L. (eds) Channel Flow, Ductile Extrusion and Exhumation in Continental Collision Zones. Geological Society, London, Special Publications, 268, 1–23. 0305-8719/06/$15.00 # The Geological Society of London 2006. . How do the pressure–temperature-time (P-T-t) data across the crystalline core of the Himalaya fit with the proposed channel flow? . Are the microstructural fabric data (pure shear and simple shear components) compatible with crustal extrusion (thickening or thinning of the slab)? . If the channel flow model is viable for the Himalaya–Tibet system, what may have initiated channel flow and ductile extrusion? . Why did the extrusion phase of the Himalayan metamorphic core apparently cease during the late Miocene–Pliocene? . Are some of the bounding faults of the potential channel still active, or were they recently active? . Is the Himalayan channel flow model exportable to other mountain ranges? This introductory paper addresses the historical, theoretical, geological and modelling aspects of crustal flow in the Himalaya–Tibet orogen. Critical tests for crustal flow in the Himalaya, and possible applications to other orogenic belts, are presented and difficulties associated with applying these tests are discussed. Personal communication citations (pers. comm. 2004) identify comments expressed during the conference. The Himalaya–Tibetan plateau system The Himalaya–Tibet system initiated in Early Eocene times, following collision of the Indian and Eurasian plates (see Hodges (2000) and Yin & Harrison (2000) for reviews). The collision resulted in closure of the Tethyan Ocean, southward imbrication of the Indian crust, and northward continental subduction of Indian lower crust and mantle beneath Asia. The collision thickened the southern edge of the Asian crust to 70 km, and created the Tibetan Plateau, the largest uplifted part of the Earth’s surface with an average elevation of 5000 m (Fielding et al. 1994). The Himalayan orogen coincides with the 2500km-long topographic front at the southern limit of the Tibetan Plateau. It consists of five broadly parallel lithotectonic belts, separated by mostly north-dipping faults (Fig. 1). The Himalayan metamorphic core, termed the Greater Himalayan sequence (GHS), is bounded by two parallel and opposite-sense shear zones that were both broadly active during the Miocene (Hubbard & Harrison 1989; Searle & Rex 1989; Hodges et al. 1992, 1996). The Main Central thrust (MCT) zone marks the lower boundary of the GHS, juxtaposing the metamorphic core above the underlying Lesser Himalayan sequence. The South Tibetan detachment (STD) system defines the upper boundary roof fault of the GHS, marking the contact with the overlying unmetamorphosed Tethyan sedimentary sequence. The apparent coeval movement of the MCT and STD, combined with the presence of highly sheared rocks and high grade to migmatitic rocks within the GHS, has led many workers to view the GHS as a north-dipping, southward-extruding slab of mid-crustal material flowing away from the thick southern edge of the Tibetan Plateau, towards the thinner foreland fold-thrust belt. Dynamics of channel flow The concepts of crustal extrusion and channel flow originated in the continental tectonics literature in the early 1990s. Unfortunately, these two processes are often referred to interchangeably without justification. One of the main points that emerged from the Burlington House conference was that a distinction between channel flow and crustal extrusion must be made. Parallel versus tapering bounding walls on channel flow and/or extrusion processes, and how these processes may replenish over time, are two resolvable parameters that are critical for distinguishing channel flow from extrusion. Brief definitions and overviews of the two processes are presented below. A more detailed overview of the mechanics of the related processes is provided by Grujic (2006).

Prevalence and Evolution of Core Photosystem II Genes in Marine Cyanobacterial Viruses and Their Hosts

Abstract: Cyanophages (cyanobacterial viruses) are important agents of horizontal gene transfer among marine cyanobacteria, the numerically dominant photosynthetic organisms in the oceans. Some cyanophage genomes carry and express host-like photosynthesis genes, presumably to augment the host photosynthetic machinery during infection. To study the prevalence and evolutionary dynamics of this phenomenon, 33 cultured cyanophages of known family and host range and viral DNA from field samples were screened for the presence of two core photosystem reaction center genes, psbA and psbD. Combining this expanded dataset with published data for nine other cyanophages, we found that 88% of the phage genomes contain psbA, and 50% contain both psbA and psbD. The psbA gene was found in all myoviruses and Prochlorococcus podoviruses, but could not be amplified from Prochlorococcus siphoviruses or Synechococcus podoviruses. Nearly all of the phages that encoded both psbA and psbD had broad host ranges. We speculate that the presence or absence of psbA in a phage genome may be determined by the length of the latent period of infection. Whether it also carries psbD may reflect constraints on coupling of viral- and host-encoded PsbA–PsbD in the photosynthetic reaction center across divergent hosts. Phylogenetic clustering patterns of these genes from cultured phages suggest that whole genes have been transferred from host to phage in a discrete number of events over the course of evolution (four for psbA, and two for psbD), followed by horizontal and vertical transfer between cyanophages. Clustering patterns of psbA and psbD from Synechococcus cells were inconsistent with other molecular phylogenetic markers, suggesting genetic exchanges involving Synechococcus lineages. Signatures of intragenic recombination, detected within the cyanophage gene pool as well as between hosts and phages in both directions, support this hypothesis. The analysis of cyanophage psbA and psbD genes from field populations revealed significant sequence diversity, much of which is represented in our cultured isolates. Collectively, these findings show that photosynthesis genes are common in cyanophages and that significant genetic exchanges occur from host to phage, phage to host, and within the phage gene pool. This generates genetic diversity among the phage, which serves as a reservoir for their hosts, and in turn influences photosystem evolution.

Coral Reefs and the Global Network of Marine Protected Areas

Abstract: Existing marine reserves are largely ineffective and as a whole remain insufficient for the protection of coral reef diversity.