Key Study Components Research Articles

Reporting and Description of Research Methodology in Studies Estimating Effects of Firearm Policies.

Evidence about which firearm policies work, to what extent, and for whom is hotly debated, perhaps partly because variation in research methodology has produced mixed and inconclusive effect estimates. We conducted a scoping review of firearm policy research in the health sciences in the United States, focusing on methodological considerations for causal inference. We identified original, empirical articles indexed in PubMed from 1 January 2000 to 1 September 2021 that examined any of 18 prespecified firearm policies. We extracted key study components, including policy type(s) examined, policy operationalization, outcomes, study setting and population, study approach and design, causal language, and whether and how authors acknowledged potential sources of bias. We screened 7733 articles and included 124. A plurality of studies used a legislative score as their primary exposure (n = 39; 32%) and did not examine change in policies over time (n = 47; 38%). Most examined firearm homicide (n = 51; 41%) or firearm suicide (n = 40; 32%) as outcomes. One-third adjusted for other firearm policies (n = 41; 33%). Three studies (2%) explicitly mentioned that their goal was to estimate causal effects, but over half used language implying causality (n = 72; 58%). Most acknowledged causal identification assumptions of temporality (n = 91; 73%) and exchangeability (n = 111; 90%); other assumptions were less often acknowledged. One-third of studies included bias analyses (n = 42; 34%). We identified a range of methodologic approaches in firearm policy research in the health sciences. Acknowledging the imitations of data availability and quality, we identify opportunities to improve causal inferences about and reporting on the effects of firearm policies on population health.

Biological carbon pump responses to multiscale physical processes: a review of sediment trap studies in the South China Sea

Accurately assessing the capacity of the modern ocean to photosynthetically fix and sequester atmospheric CO2, termed the biological carbon pump (BCP), is a key component in studies on the marine carbon cycle and the global climate system. Particulate organic carbon (POC) flux into the ocean interior is an important indicator of the BCP strength, and it can be directly measured by sediment traps on time scales from days to years. This study has been conducted in the South China Sea (SCS) for over three decades. The SCS is one of the largest tropical marginal seas, located in the Asian monsoon region with frequent occurrence of dynamic physical processes and anthropogenic perturbations. It hosts an ideal natural laboratory to investigate the response of the BCP to multiscale physical processes. In this mini review, we briefly introduce the study history of mooring sediment traps in the SCS, synthesize the processes that regulate the temporal variability in mesopelagic POC flux, and how it is sensitive to climate changes. The time-series characteristics of the POC flux are clearly linked to primary production, as well as the key physical processes in the upper layer. The seasonal East Asian monsoon, intraseasonal eddies, aerosol deposition and interannual El Niño Southern Oscillation (ENSO) events are the main controlling factors over weekly to yearly timescales. Together, they suggest that the multiscale physical forcing in the upper layer regulates the mesopelagic POC export flux by controlling nutrient supplementation and subsequent POC production.

Reciprocal associations between housing instability and youth criminal legal involvement: a scoping review

BackgroundYouth experiencing homelessness have disproportionate contact with the criminal legal system. This system contact represents a critical inflection point for enhancing risk or opportunities for stabilization; however, the policy and scholarly traditions examining the criminal legal system have not traditionally incorporated housing or other social determinants as a central focus of intervention.MethodsWe conducted a scoping review using PRISMA-ScR guidelines to examine how the research literature is currently addressing housing within the context of youth involvement in the legal system. Databases searched included PubMed, Web of Science, and Academic Search Complete. Google Scholar was used to identify papers not indexed in the academic databases of interest. Database searches were conducted between September and December 2019 and articles were restricted to those published in English between the year 2000 and 2019. Key study components extracted included demographic information regarding each sample, type of article, study methodology, direction of effects of interest, outcome measures and primary findings, as well as theoretical frameworks engaged by the authors.ResultsThe search results returned 2154 titles for review. After screening all 2154 titles, 75 met eligibility for inclusion. reviews were conducted for all 75 papers. 36 abstracts met eligibility criteria and underwent full-text review. Ultimately, 29 articles satisfied eligibility criteria and were included in this scoping review.ConclusionsPublications are primarily focused on the social epidemiology of risk factors and behaviors determining youth justice contact, but relatively less so on studies of interventions targeting youth delinquency, crime reduction, or recidivism that included housing support. The lack of continuity in theorizing from epidemiology to applied science in this area represents a gap in the literature that is likely reducing the effectiveness of interventions to interrupt patterns of legal system contact for youth. Integrating a public health framework that emphasizes the upstream social determinants leading to contact with the youth justice system would represent a paradigm shift for the field that would have beneficial effects on long term health outcomes for youth.

Wind integration cost in China: A production simulation approach and case study

The integration cost of large-scale variable renewable energy (VRE) in China’s coal-dominated inflexible power systems is of significant concern when studying the generation cost of VRE. One key component of studies about integration cost is the question of how to estimate the impact of large-scale VRE integrated into power systems on the operation mode of conventional generators. It is intuitive to compare system-level costs with and without VRE under a benchmarked system. In this study, we employ a unit commitment (UC) model to simulate the output of various types of units based on minimizing the total power system cost. Then, we estimate the conventional generator operation cost change caused by the change of operation mode. Using the power system in Jilin province as a typical case, the integration cost will increase with increased VRE penetration, reaching 123.5 CNY/MWh at 40% penetration level. The idle cost of the coal-fired power units accounts for 69% of the integration cost at 40% VRE penetration, the highest proportion; wind curtailment cost ranks second for 26%, while the incremental operating cost of coal power accounts for 4.7%. With a long-term perspective, establishing a complete power market and adopting an appropriate pricing mechanism to incentivize system flexibility is the best solution for adopting VRE.

A pilot randomised placebo-controlled trial of cannabidiol to reduce severe behavioural problems in children and adolescents with intellectual disability.

Severe behavioural problems (SBP) are a major contributor to morbidity in children with intellectual disability (ID). Medications used to treat SBP in ID are associated with a high risk of side effects. Cannabidiol has potential therapeutic effects in SBP. This pilot study aimed to investigate the feasibility of conducting a randomised placebo-controlled trial of cannabidiol to reduce SBP in children with ID. This is a double-blind, placebo-controlled, two-armed, parallel-design, randomised controlled trial of cannabidiol in children aged 8-16 years with ID and SBP. Participants were randomised 1:1 to receive either 98% cannabidiol in oil (Tilray, Canada) or placebo orally for 8 weeks. The dose was up-titrated over 9 days to 20 mg/kg/day in two divided doses, with a maximum dose of 500 mg twice/day. The feasibility and acceptability of all study components were assessed. Eight children were randomised, and all completed the full study protocol. There were no serious adverse events or drop-outs. Protocol adherence for key study components was excellent: study visits 100%, medication adherence 100%, blood tests 92% and questionnaire completion 88%. Parents reported a high degree of acceptability with the study design. All parents reported they would recommend the study to other families with children with similar problems. There was an efficacy signal in favour of active drug. The findings suggest that the study protocol is feasible and acceptable to patients with ID and SBP and their families.

Tomographic filtering via the generalized inverse: a way to account for seismic data uncertainty

SUMMARY Tomographic-geodynamic model comparisons are a key component in studies of the present-day state and evolution of Earth’s mantle. To account for the limited seismic resolution, ‘tomographic filtering’ of the geodynamically predicted mantle structures is a standard processing step in this context. The filtered model provides valuable information on how heterogeneities are smeared and modified in amplitude given the available seismic data and underlying inversion strategy. An important aspect that has so far not been taken into account are the effects of data uncertainties. We present a new method for ‘tomographic filtering’ in which it is possible to include the effects of random and systematic errors in the seismic measurements and to analyse the associated uncertainties in the tomographic model space. The ‘imaged’ model is constructed by computing the generalized-inverse projection (GIP) of synthetic data calculated in an earth model of choice. An advantage of this approach is that a reparametrization onto the tomographic grid can be avoided, depending on how the synthetic data are calculated. To demonstrate the viability of the method, we compute traveltimes in an existing mantle circulation model (MCM), add specific realizations of random seismic ‘noise’ to the synthetic data and apply the generalized inverse operator of a recent Backus–Gilbert-type global S-wave tomography. GIP models based on different noise realizations show a significant variability of the shape and amplitude of seismic anomalies. This highlights the importance of interpreting tomographic images in a prudent and cautious manner. Systematic errors, such as event mislocation or imperfect crustal corrections, can be investigated by introducing an additional term to the noise component so that the resulting noise distributions are biased. In contrast to Gaussian zero-mean noise, this leads to a bias in model space; that is, the mean of all GIP realizations also is non-zero. Knowledge of the statistical properties of model uncertainties together with tomographic resolution is crucial for obtaining meaningful estimates of Earth’s present-day thermodynamic state. A practicable treatment of error propagation and uncertainty quantification will therefore be increasingly important, especially in view of geodynamic inversions that aim at ‘retrodicting’ past mantle evolution based on tomographic images.

Mean annual attachment, bone level, and tooth loss: A systematic review.

Rate of progression of periodontitis has been used to inform the design of classifications of periodontal diseases. However, the evidence underpinning this topic is unclear and no systematic review has yet been conducted. The focused question for this systematic review was: in adults, what is the progression of periodontitis in terms of clinical attachment loss, radiographic bone loss, and tooth loss? Highly sensitive electronic search was conducted for published data in MEDLINE, EMBASE, LILACS, and unpublished grey literature in OpenGrey up to February 2016. Reference lists of retrieved studies for full-text screening and reviews were hand-searched for potentially eligible studies. Prospective, longitudinal observational studies with follow-up of at least 12 months and presenting data on the primary outcome, change in clinical attachment level, in adults (age ≥18 years). Secondary outcomes, tooth loss and bone level change, were only assessed in studies reporting the primary outcome. Studies investigating specific disease populations or only on treated periodontitis patients were excluded. Risk of bias and methodology were assessed using the Newcastle-Ottawa Scale with two additional questions on security of outcome assessment. Studies were pooled by abstracting or estimating mean annual attachment or bone level change and annual tooth loss. Random effects meta-analysis was conducted with investigation of effect of potential modifiers where possible. A total 11,482 records were screened for eligibility; 33 publications of 16 original studies reporting on more than 8,600 participants were finally included as eligible for the review. The studies represented populations from both developing and developed economies. Mean annual attachment loss was 0.1mm per year (95% CI 0.068, 0.132; I2 =99%) and mean annual tooth loss was 0.2 teeth per year (95% CI 0.10, 0.33; I2 =94%). Observational analysis of highest and lowest mean attachment change quintiles suggested substantial differences between groups with minimal annual change in the lowest quintile and an average deterioration of 0.45mm mean attachment loss per year in the highest group. This value increased to 0.6mm per year with periodontitis alone. There was surprisingly little effect of age or gender on attachment level change. Geographic location, however, was associated with more than three times higher mean annual attachment loss in Sri Lanka and China (0.20mm, 95% CI 0.15, 0.27; I2 =83%) vs North America and Europe (0.056mm, 95% CI 0.025, 0.087; I2 =99%) P<0.001. There were a limited number of studies (N=16), high variability of design in key study components (sampling frames, included ages, data analyses), and high statistical heterogeneity that could not be explained. Within the limitations of the research, the data show that mean annual attachment level change varies considerably both within and between populations. Overall, the evidence does not support or refute the differentiation between forms of periodontal diseases based upon progression of attachment level change.

Mean annual attachment, bone level, and tooth loss: A systematic review

Rate of progression of periodontitis has been used to inform the design of classifications of periodontal diseases. However, the evidence underpinning this topic is unclear and no systematic review has yet been conducted. The focused question for this systematic review was: in adults, what is the progression of periodontitis in terms of clinical attachment loss, radiographic bone loss, and tooth loss? Highly sensitive electronic search was conducted for published data in MEDLINE, EMBASE, LILACS, and unpublished grey literature in OpenGrey up to February 2016. Reference lists of retrieved studies for full-text screening and reviews were hand-searched for potentially eligible studies. Prospective, longitudinal observational studies with follow-up of at least 12 months and presenting data on the primary outcome, change in clinical attachment level, in adults (age ≥18 years). Secondary outcomes, tooth loss and bone level change, were only assessed in studies reporting the primary outcome. Studies investigating specific disease populations or only on treated periodontitis patients were excluded. Risk of bias and methodology were assessed using the Newcastle-Ottawa Scale with two additional questions on security of outcome assessment. Studies were pooled by abstracting or estimating mean annual attachment or bone level change and annual tooth loss. Random effects meta-analysis was conducted with investigation of effect of potential modifiers where possible. A total 11,482 records were screened for eligibility; 33 publications of 16 original studies reporting on more than 8,600 participants were finally included as eligible for the review. The studies represented populations from both developing and developed economies. Mean annual attachment loss was 0.1mm per year (95% CI 0.068, 0.132; I2 =99%) and mean annual tooth loss was 0.2 teeth per year (95% CI 0.10, 0.33; I2 =94%). Observational analysis of highest and lowest mean attachment change quintiles suggested substantial differences between groups with minimal annual change in the lowest quintile and an average deterioration of 0.45mm mean attachment loss per year in the highest group. This value increased to 0.6mm per year with periodontitis alone. There was surprisingly little effect of age or gender on attachment level change. Geographic location, however, was associated with more than three times higher mean annual attachment loss in Sri Lanka and China (0.20mm, 95% CI 0.15, 0.27; I2 =83%) vs North America and Europe (0.056mm, 95% CI 0.025, 0.087; I2 =99%) P<0.001. There were a limited number of studies (N=16), high variability of design in key study components (sampling frames, included ages, data analyses), and high statistical heterogeneity that could not be explained. Within the limitations of the research, the data show that mean annual attachment level change varies considerably both within and between populations. Overall, the evidence does not support or refute the differentiation between forms of periodontal diseases based upon progression of attachment level change.

Demographic and Operational Factors Predicting Study Completion in a Multisite Case-Control Study of Preschool Children.

Participant attrition can limit inferences drawn from study results and inflate research costs. We examined factors associated with completion of the Study to Explore Early Development (2007-2011), a multiple-component, case-control study of risk factors for autism spectrum disorder in preschoolers, conducted in California, Colorado, Georgia, Maryland, North Carolina, and Pennsylvania. Participants (n = 3,769) were asked to complete phone interviews, questionnaires, an in-person evaluation, and biologic sampling. We examined whether participant demographic and administrative factors predicted completion using mixed-effects logistic regression models. Completion of individual key study components was generally 70% or higher. However, 58% of families completed all per-protocol data elements (defined a priori as key study components). Per-protocol completion differed according to mother's age, race, educational level, driving distance to clinic, number of contact attempts to enroll, and number of telephone numbers provided (all P < 0.05). Case status was not associated with completion, despite additional data collection for case-confirmation. Analysis of a subset that completed an early interview revealed no differences in completion by household factors of income, primary language spoken, number of adults, or number of children with chronic conditions. Differences in completion by race and education were notable and need to be carefully considered in developing future recruitment and completion strategies.

Effectiveness of early quadriceps exercises after anterior cruciate ligament reconstruction

Objective. To systematically review the published information regarding the effectiveness and safety of early postoperative quadriceps muscle exercise training on pain, joint laxity, function and range of motion in postoperative anterior cruciate ligament (ACL) reconstruction adult patients. Data sources. Five databases (CINAHL, PEDro, Pubmed, Science Direct and the Cochrane Library) were searched for studies published from January 1990 to May 2007. Study selection. Publications describing research into the effectiveness of early quadriceps exercises after ACL reconstruction were included. A total of three eligible articles met the inclusion criteria. Data extraction. A review of the three eligible studies was undertaken to describe the key study components. The PEDro Scale was used to determine the methodological quality of the selected trials and the level of evidence of all the eligible studies was categorised according to the evidence hierarchy by Lloyd-Smith.24 Relevant data were extracted by the two reviewer groups to reduce bias. Data synthesis. Due to study heterogeneity a meta-analysis could not be conducted. Effect sizes were calculated provided that sufficient data were provided. Outcome measures included range of motion (ROM), functional performance, pain and knee laxity. The methodological quality of the studies did not vary considerably across the studies and the average PEDro score was 66%. Marginal significant differences were noted in knee ROM at 1 month postoperatively, pain day 1 postoperatively, knee laxity and subjective evaluation of function at 6 months postoperatively. Conclusion. Early quadriceps exercises can be performed safely in the first 2 postoperative weeks, but clinically significant gains in ROM, function, pain and knee laxity were not evident. Further research should include standardised interventions, measurement time frames and outcome measurement tools to allow for a meta- analysis to be conducted

A unified analysis of niche overlap incorporating data of different types

Summary1. Competition theory predicts that community structure may be shaped by resource partitioning between co‐occurring species. As such, quantifying the degree of resource partitioning (i.e., niche overlap) is a key component of studies examining community structure and species coexistence.2. For many organisms, multiple resource axes quantify niche space. Each axis may be described by a different type of data (e.g. categorical, continuous, count or binary data, as well as electivity scores), with different data types requiring different statistical treatments. Therefore, incorporating multiple axes into a single measure of niche space is problematic.3. Here, we propose general methods for combining multiple niche axes, each characterized by different data types, within a unified analysis of niche overlap. Using appropriate transformations and probability models, we show that each data type can give rise to directly comparable measures of niche overlap, with the overlap statistic between two species defined as the overlapping area between the distributions for each species.4. Measurements derived from different types of data can be combined into a single unified analysis of niche overlap by averaging over multiple axes.5. We then describe null model permutation tests that assess statistical differences in niche overlap, which can address questions commonly posed by population ecologists (e.g. do two species occupy different niche space?) and community ecologists (e.g. are multiple species evenly distributed across niche space?).6. To illustrate the use of these newly devised indices, we use an example from reef fishes that combines ratio, categorical and electivity data, and an example from alpine plants that combines continuous and ratio data.7. The methods described in this article are relevant to a wide variety of ecological projects, including the investigation of invasive species, relative abundance distributions, global change, species coexistence and evolutionary diversification.

Spring migration timing of Sylvia warblers in Tatarstan (Russia) 1957–2008

Abstract The timing of when migrant birds return to breed is a key component of studies of the impact of climate change upon bird populations. However, such data are not distributed evenly across the World, and in the Northern Hemisphere are underrepresented in Asia and the east of Europe. Therefore, to help rectify this bias, we analysed first arrival dates (FAD) of four species of Sylvia warblers (Blackcap Sylvia atricapilla, Whitethroat S.communis, Lesser Whitethroat S.curruca and Garden Warbler S.borin) collected in the Tatarstan Republic of Russia between 1957 and 2008. Over the whole period the species returned to their breeding sites between three and six days earlier; these trends were significant except for Whitethroat. Advances in arrival were especially apparent in the two earlier species, Blackcap and Lesser Whitethroat, mainly because local temperatures for March had risen substantially. Except for Whitethroat, FADs were significantly related to temperatures in the African wintering ground and/or in Tatarstan. Whilst significant correlations occurred between FADs of some of the species, there was considerable variability in these relationships indicating a species-specific response to rising temperatures. Changes in FADs in this eastern extremity of Europe were smaller than in Central and Western Europe.

Effectiveness of early quadriceps exercises after anterior cruciate ligament reconstruction : review

Objective. To systematically review the published information regarding the effectiveness and safety of early postoperative quadriceps muscle exercise training on pain, joint laxity, function and range of motion in postoperative anterior cruciate ligament (ACL) reconstruction adult patients. Data sources. Five databases (CINAHL, PEDro, Pubmed, Science Direct and the Cochrane Library) were searched for studies published from January 1990 to May 2007. Study selection. Publications describing research into the effectiveness of early quadriceps exercises after ACL reconstruction were included. A total of three eligible articles met the inclusion criteria. Data extraction. A review of the three eligible studies was undertaken to describe the key study components. The PEDro Scale was used to determine the methodological quality of the selected trials and the level of evidence of all the eligible studies was categorised according to the evidence hierarchy by Lloyd-Smith. Relevant data were extracted by the two reviewer groups to reduce bias. Data synthesis. Due to study heterogeneity a meta-analysis could not be conducted. Effect sizes were calculated provided that sufficient data were provided. Outcome measures included range of motion (ROM), functional performance, pain and knee laxity. The methodological quality of the studies did not vary considerably across the studies and the average PEDro score was 66%. Marginal significant differences were noted in knee ROM at 1 month postoperatively, pain day 1 postoperatively, knee laxity and subjective evaluation of function at 6 months postoperatively. Conclusion. Early quadriceps exercises can be performed safely in the first 2 postoperative weeks, but clinically significant gains in ROM, function, pain and knee laxity were not evident. Further research should include standardised interventions, measurement time frames and outcome measurement tools to allow for a meta-analysis to be conducted.

Effectiveness of early quadriceps exercises after anterior cruciate ligament reconstruction

Objective. To systematically review the published information regarding the effectiveness and safety of early postoperative quadriceps muscle exercise training on pain, joint laxity, function and range of motion in postoperative anterior cruciate ligament (ACL) reconstruction adult patients. Data sources. Five databases (CINAHL, PEDro, Pubmed, Science Direct and the Cochrane Library) were searched for studies published from January 1990 to May 2007. Study selection. Publications describing research into the effectiveness of early quadriceps exercises after ACL reconstruction were included. A total of three eligible articles met the inclusion criteria. Data extraction. A review of the three eligible studies was undertaken to describe the key study components. The PEDro Scale was used to determine the methodological quality of the selected trials and the level of evidence of all the eligible studies was categorised according to the evidence hierarchy by Lloyd-Smith.24 Relevant data were extracted by the two reviewer groups to reduce bias. Data synthesis. Due to study heterogeneity a meta-analysis could not be conducted. Effect sizes were calculated provided that sufficient data were provided. Outcome measures included range of motion (ROM), functional performance, pain and knee laxity. The methodological quality of the studies did not vary considerably across the studies and the average PEDro score was 66%. Marginal significant differences were noted in knee ROM at 1 month postoperatively, pain day 1 postoperatively, knee laxity and subjective evaluation of function at 6 months postoperatively. Conclusion. Early quadriceps exercises can be performed safely in the first 2 postoperative weeks, but clinically significant gains in ROM, function, pain and knee laxity were not evident. Further research should include standardised interventions, measurement time frames and outcome measurement tools to allow for a meta- analysis to be conducted

Capecitabine, oxaliplatin, radiotherapy, and excision (CORE) in patients with MRI-defined locally advanced rectal adenocarcinoma: Results of an international multicenter phase II study

3528 Background: The addition of chemotherapy to preoperative radiotherapy (RT) may reduce distant recurrence and increase tumor resectability. The CORE study evaluated oxaliplatin, capecitabine, and RT (XELOX-RT) followed by total mesorectal excision (TME), then adjuvant XELOX in patients (pts) with MRI-defined locally advanced rectal cancer. Methods: MRI inclusion criteria: tumor beyond mesorectal fascia, tumor ≤2 mm from mesorectal fascia, or T3/4 tumor &lt;5 cm from anal verge. Chemoradiation (CRT) was 45 Gy RT (1.8 Gy/dose) 5 days/wk for 5 wks, weekly oxaliplatin 50 mg/m2, and twice-daily capecitabine 825 mg/m2 on each day of RT. Surgery was 6–8 wks after completing XELOX-RT. Pts with R0-R1 resection were to receive XELOX for 6 cycles. Central radiologic and histopathologic review were key study components. Processes to determine histopathologic response and circumferential resection margin (CRM) were predefined. The primary endpoint was pCR rate (planned n=70 evaluable pts). Results: Between July 2003 and Dec 2004, 87 pts were enrolled; 85 pts received XELOX-RT and 79 had TME. Seventy pts (82%) had R0-R1 resection, with a 67% R0 rate (n=57) by Quirke methodology (CRM &gt;1 mm). The pCR rate was 13% (10/78 pts assessable for tumor response; 95% CI, 5.46–20.34%). Tumor regression grading showed excellent response in 35% and poor response in 64% of pts. Of 60 pts evaluated by central MRI review for response by RECIST, the overall response rate was 70% (7% complete; 63% partial response). Preoperative grade (G) 3/4 adverse events (% of pts; evaluable n=85) included diarrhea 16% (12% G3), sensory neuropathy 1% (G3), neutropenia 1% (G3), and hand-foot syndrome 1% (G3). More than 90% of pts received full dose radiotherapy. Conclusions: Significant tumor regression and a high R0 resection rate were achieved using a CRT regimen of preoperative oxaliplatin, capecitabine, and 45 Gy RT, with acceptable toxicity. Central histopathologic and radiologic review data, together with safety and efficacy results for both preoperative CRT and postoperative chemotherapy, will be presented. [Table: see text]

Biomechanical factors associated with the risk of knee injury when landing from a jump

Objectives. To systematically assess the literature investigating biomechanical knee injury risk factors when an individual lands from a jump. Data sources. Four electronic databases were searched for peer-reviewed English journals containing landing biomechanical studies published over 14 years (1990 - 2003). Study selection. Publications describing research into knee joint kinetics and/or kinematics when landing from a jump were included. A total of 26 eligible articles met the inclusion criteria. Data extraction. A review of the 26 eligible studies was undertaken to describe the key study components including the study aims, sample populations, measurement tools, measurement procedures and knee risk factors. Methodological quality was scored using the Crombie Checklist and PEDro Scale. Data synthesis. The methodological quality of the studies reviewed was fair. Information on risk factors was variable. One proposed risk factor, landing with the knee in a relatively more extended position, may increase injury risk. Validity was compromised when the landing action was isolated by studying drop-jumping instead of the whole landing task. Results of reviewed studies were potentially confounded by a number of factors. Conclusion. High-level evidence for biomechanical knee injury risk factors when landing from a jump is lacking and it is difficult to draw conclusions regarding knee injury risk factors when landing. However, the published research reviewed provides important information on injury causality and theories to direct future studies. Further research should be directed towards younger populations using valid testing protocols applicable to real life scenarios. South African Journal of Sports Medicine Vol. 18 (1) 2006: pp. 18-23

Present-at-admission diagnoses improve mortality risk adjustment and allow more accurate assessment of the relationship between volume of lung cancer operations and mortality risk

Mortality risk adjustment is a key component of studies that examine the statistical relationship between hospital lung cancer operation volume and in-hospital mortality. Previous studies of this relationship have used different methods of adjusting for factors that influence mortality risk, but none have adjusted for differences in comorbid disease using only diagnoses identified as present-at-admission. This study uses adjustments for conditions identified as present-at-admission to examine the statistical relationship between the volume of lung cancer operations and mortality among 14,456 California hospital patients, and compares these results to other methods of risk adjustment similar to those used in previous studies. Mortality risk adjustment using present-at-admission diagnoses yielded better discrimination and explained more of the variability in observed deaths. Large increases in hospital procedure volume were associated with much smaller decreases in mortality risk than those estimated using comparable risk-adjustment models. Present-at-admission diagnoses can be used to improve mortality risk adjustment and may allow a more accurate assessment of the relationship between procedure volume and mortality risk.

Molecular haplotyping at high throughput.

Reconstruction of haplotypes, or the allelic phase, of single nucleotide polymorphisms (SNPs) is a key component of studies aimed at the identification and dissection of genetic factors involved in complex genetic traits. In humans, this often involves investigation of SNPs in case/control or other cohorts in which the haplotypes can only be partially inferred from genotypes by statistical approaches with resulting loss of power. Moreover, alternative statistical methodologies can lead to different evaluations of the most probable haplotypes present, and different haplotype frequency estimates when data are ambiguous. Given the cost and complexity of SNP studies, a robust and easy-to-use molecular technique that allows haplotypes to be determined directly from individual DNA samples would have wide applicability. Here, we present a reliable, automated and high-throughput method for molecular haplotyping in 2 kb, and potentially longer, sequence segments that is based on the physical determination of the phase of SNP alleles on either of the individual paternal haploids. We demonstrate that molecular haplotyping with this technique is not more complicated than SNP genotyping when implemented by matrix-assisted laser desorption/ionisation mass spectrometry, and we also show that the method can be applied using other DNA variation detection platforms. Molecular haplotyping is illustrated on the well-described beta(2)-adrenergic receptor gene.

Organizational types and organizational innovation : Downsizing among industrial, financial, and utility firms

Given the importance of innovation to organizations and to society-at-large, scholars have asked: Why do organizations innovate? Institutionalists argue that the causes of innovation vary by organizational type: While technicoeconomic forces should trigger innovation among “efficiency-minded” organizations, social and cultural forces should spur innovation among “institutionalized” organizations. Building on this argument, I specify two organizational orientations—efficiency and institutional—and formulate general hypotheses on the degree to which technicoeconomic versus sociocultural forces should produce innovation among three types of organizations—industrial, financial, and utility firms. I draw on these general hypotheses in examining the causes of a major yet underexamined innovation, organizational downsizing, from 1979 to 1995. The findings indicate that the causes of downsizing among industrial, financial, and utility firms vary according to theoretical logic, revealing that there are limits to the generalizability of efficiency-based and institutional explanations of innovation; however, these limits are precisely those predicted by the theoretical framework. I conclude by stressing the advantages of making the investigation of organizational types a key component of studies on organizations.