Partial Correlation Test Research Articles

Geometry of the faithfulness assumption in causal inference

Many algorithms for inferring causality rely heavily on the faithfulness assumption. The main justification for imposing this assumption is that the set of unfaithful distributions has Lebesgue measure zero, since it can be seen as a collection of hypersurfaces in a hypercube. However, due to sampling error the faithfulness condition alone is not sufficient for statistical estimation, and strong-faithfulness has been proposed and assumed to achieve uniform or high-dimensional consistency. In contrast to the plain faithfulness assumption, the set of distributions that is not strong-faithful has nonzero Lebesgue measure and in fact, can be surprisingly large as we show in this paper. We study the strong-faithfulness condition from a geometric and combinatorial point of view and give upper and lower bounds on the Lebesgue measure of strong-faithful distributions for various classes of directed acyclic graphs. Our results imply fundamental limitations for the PC-algorithm and potentially also for other algorithms based on partial correlation testing in the Gaussian case.

The relationship between synovial fluid ARGS, cytokines, MMPs & TIMPs following acute ACL injury

s / Osteoarthritis and Cartilage 21 (2013) S63–S312 S75 active ADAMTS-4 where surface fibrillation and clustered chondrocytes were observed and lost when there was no proteoglycan observed. MMP-9 staining was strong throughout the OA sections when pronounced OA characteristics, such as fibrillation, erosion and hypertrophy, were present Conclusions: Better understanding on the dynamics of proteolytical activity profiles in OA cartilage may aid in improved insight to joint pathology. This should lead to enhanced targeting of novel intervention for OA. 123 THE RELATIONSHIP BETWEEN SYNOVIAL FLUID ARGS, CYTOKINES, MMPS & TIMPS FOLLOWING ACUTE ACL INJURY T.W. Tourville y, R.J. Johnson y, J.R. Slauterbeck y, S. Naud y, L.S. Lohmander z,x, A. Struglics z, B.D. Beynnon y. yUniv. of Vermont Coll. of Med., Burlington, VT, USA; z Lund Univ., Dept. of Orthopaedics, Clinical Sci. Lund, Lund, Sweden; xRes. Unit for Musculoskeletal Function and Physiotherapy, Inst. for Sports and Clinical Biomechanics, Univ. of Southern Denmark, Denmark, Sweden Purpose: Injury to the Anterior Cruciate Ligament (ACL) results in a high incidence of Post-Traumatic Osteoarthritis (PTOA). Limited information is available regarding the role of inflammatory mediators in PTOA, especially during the onset and earliest stages of the disease process. Recent investigations have provided evidence that a biochemical response occurs very soon after acute knee trauma, and aggrecan degradation (evidenced by elevated levels of synovial fluid (SF) aggrecanase generated N-terminal ARGS) is associated with inflammatory activity during the initial few weeks following acute ACL rupture. It is not known, however, if this process persists for a longer time interval following trauma; if ARGS concentrations are associated with additional cytokines not previously described; or how ARGS concentrations relate to levels of matrix metalloproteases (MMPs) or tissue inhibitors of metalloproteases (TIMPs) found in the synovial fluid following ACL disruption. Consequently, the purpose of this study was to evaluate relationships between SF ARGS levels and an array of cytokines, MMPs and TIMPs within the 6 months following acute ACL rupture. Methods: Synovial fluid samples from 67 ACL-injured patients (29 women) were used for analysis in this exploratory, cross sectional study. Entry criteria included: Age at the time of enrollment 1⁄4 1455yrs; BMI 1⁄4 18.5-30, Tegner score > 4; no relevant knee pathologies other than the index ACL injury; normal lower extremity alignment; and relatively minor articular cartilage and meniscal pathologies. All samples were obtained within 6 months of injury (18-155 days) via non-lavage arthrocentesis immediately prior to surgical ACL reconstruction. SF samples were analyzed for ARGS concentration via electrochemiluminescence immunoassay. Concentrations of 42 different cytokines were evaluated using commercially available Luminex-based multiplex analysis kits (42-Plex), as were 8 MMPs (panels 1 & 2), and 4 TIMPs (panel 1) (Millipore, Billerica, MA). Relationships between ARGS concentrations and individual analyte concentrations as well as MMP/TIMP ratios were evaluated statistically with partial Spearman Partial Correlation tests (rs), while adjusting for age, sex, and time since injury. This analysis technique was chosen because it is not strongly influenced by normality of data or “outliers.” Results: Statistically significant relationships were found between ARGS concentrations and FGF-2 (rs 1⁄4 -0.27, p 1⁄4 0.03) and TIMP-3 (rs 1⁄4 0.33, p 1⁄4 0.01). Although not statistically significant, FLT-3L, IP-10, and TIMP-1 had correlations greater than 0.20 (absolute values), trending toward significant correlations (Table 1). All other analytes tested received r-values less than 0.2 and were not significant.

A longitudinal study of BDNF promoter methylation and genotype with poststroke depression

IntroductionBrain derived neurotrophic factor (BDNF) has been shown to play an important role in the pathophysiology of mood disorders including poststroke depression (PSD). BDNF secretion is influenced by epigenetic and genetic profiles. This study aimed to investigate whether BDNF gene promoter methylation status and val66met polymorphism were associated with depression ascertained at two weeks and one year after stroke. MethodsA total of 286 patients were evaluated two weeks after stroke, and 222 (78%) were followed one year later. Depression (major or minor depressive disorder) was diagnosed according to DSM-IV criteria, and classified into prevalent, persistent, and incident PSD according to presence at the two examinations. Depression severity was assessed by the Hospital Anxiety and Depression Scale-depression subscale and the Hamilton Depression Rating Scale. The effects of BDNF methylation status and genotype on PSD status were investigated using multivariate logistic regression models. The associations of BDNF methylation status and genotype with score on depression assessment scales were estimated using partial correlation tests and general linear models, respectively. ResultsHigher BDNF methylation status was independently associated with prevalent, persistent and particularly with incident PSD, and with worsening depressive symptoms over follow-up but not with baseline severity. The BDNF val66met polymorphism was independently associated with prevalent PSD, but not with persistent and incident PSD nor with depressive symptoms severity. No significant methylation-genotype interactions were found. LimitationsMethylation status was investigated with limited area of the BDNF gene and sample size was relatively small. ConclusionsA role for BDNF in PSD was supported, and associations with BDNF gene methylation status may represent a target for drug development.

音圧−粒子速度センサの安定性への湿度の影響

To examine humidity influence on stability of pu-sensors, we applied calibration and the ensemble averaged surface normal impedance method (EA-Method) under controlled relative humidity (φ =35-60%) in a reverberation room. Experiments revealed that calibration results (i.e. correction values) changed as humidity levels varied. A comparison of standard deviations on absorption coefficients generated increasing value as the humidity difference between calibration and measurement increased (Δφ =0-25%). Repeatability was demonstrated by using two identical pu-sensors in four set measurements. Furthermore, a partial correlation test demonstrated the dominance of humidity over other environmental factors influencing sensor sensitivity.

Formation Of The Pro-Social Behaviour Among Adolescent Audience Through Exposure To Films

This research studies the relationship between the exposure of films towards the formation of pro-social behaviour among the adolescent audiences. The social cognitive theory was used as the theoretical framework through the observational learning construct and acts as the intervening variable. The cross-sectional survey was employed in this research as the research design. Data were collected from the distribution of questionnaire through the stratified random sampling method. There were 1028 respondents involved in the research. The questionnaire was constructed from the combination of self-developed questionnaire and Prosocial Personality Battery (PSB). The analysis through partial correlation test shows a significant positive relationship between exposure to films (r= 0.246, p <.05) and prosocial behaviour by controlling the intervening variable. Based on the multiple-regression test, exposure to films and observational learning are the main predictor factors that contribute to the prosocial behaviour for 28.3 percent. Keywords : Films exposure, prosocial behaviour, social cognitive theory, observational learning

Intima‐media thickness in an Italian psoriatic population: correlation with lipidic serum levels, PASI and BMI

Recent findings have shown that psoriasis is frequently associated with atherosclerosis. Intima-media thickness (IMT) is a surrogate marker of atherosclerosis damage. Psoriasis patients had impaired endothelial function and thicker IMT of the carotid artery, compared with the healthy control subjects. The aim of our study is to evaluate the prevalence of subclinical atherosclerosis in patients affected by cutaneous psoriasis without arthritis, considering the IMT as a subclinical feature of atherosclerosis. Intima-media thickness of the common carotid artery was measured using High-resolution B-mode ultrasound in 40 psoriasis patients and 40 control patients matched for age and gender. We also measured triglycerides, PASI, total cholesterol, LDL cholesterol and BMI. Pearson's partial correlation test was used to determine the correlation between each variable. Intima-media thickness in subjects with psoriasis was statistically higher than those in the control subjects (1.465 mm, P value < 0.001). A positive strong correlation between IMT and age (r = 0.464 P < 0.01), total cholesterol (r = 0.466 P < 0.01), LDL cholesterol (r = 0.518 P < 0.01), triglycerides (r = 0.285 P = 0.01) and PASI (r = 0.515 P < 0.01) was observed. There was no statistically significant correlation between IMT and BMI (r = 0.132 P = 0.244). Our study showed a significant increase in IMT in cutaneous psoriatic patients with moderate to severe psoriasis compared with a control group. IMT seems to be uncorrelated with BMI value. It can be assumed that the assessment of IMT, through a reliable and non-invasive technique such as ultrasound, appears particularly useful in the clinical evaluation of patients with psoriasis who may benefit from early intervention.

Associations of BDNF Genotype and Promoter Methylation with Acute and Long-Term Stroke Outcomes in an East Asian Cohort

BackgroundBrain derived neurotrophic factor (BDNF) has been shown to play an important role in poststroke recovery. BDNF secretion is influenced by genetic and epigenetic profiles. This study aimed to investigate whether BDNF val66met polymorphism and promoter methylation status were associated with outcomes at two weeks and one year after stroke.Methods and FindingsA total of 286 patients were evaluated at the time of admission and two weeks after stroke, and 222 (78%) were followed one year later in order to evaluate consequences of stroke at both acute and chronic stages. Stroke outcomes were dichotomised into good and poor by the modified Rankin Scale. Stroke severity (National Institutes of Health Stroke Scale), physical disability (Barthel Index), and cognitive function (Mini-Mental State Examination) were measured. Associations of BDNF genotype and methylation status on stroke outcomes and assessment scale scores were investigated using logistic regression, repeated measures ANOVA and partial correlation tests. BDNF val66met polymorphism was independently associated with poor outcome at 2 weeks and at 1 year, and with worsening physical disability and cognitive function over that period. Higher BDNF promoter methylation status was independently associated with worse outcomes at 1 year, and with the worsening of physical disability and cognitive function. No significant genotype-methylation interactions were found.ConclusionsA role for BDNF in poststroke recovery was supported, and clinical utility of BDNF genetic and epigenetic profile as prognostic biomarkers and a target for drug development was suggested.

Risk factors associated with brachial–ankle pulse wave velocity among peritoneal dialysis patients in Macao

BackgroundCardiovascular disease is the leading cause of mortality among peritoneal dialysis (PD) patients in Macao. Increased arterial stiffness determined by pulse wave velocity (PWV) has been established as an independent predictor of cardiovascular mortality in end-stage renal disease patients. The present study aims to investigate the relationship between arterial stiffness and its associated risk factors in chronic PD patients.MethodsA total of 96 chronic PD patients (48 males/48 females) were included in the cross-sectional study. Arterial stiffness was assessed by brachial-ankle PWV (baPWV). Patients were divided into two subgroups according to mean baPWV value. On enrollment, clinical characteristics and biochemical parameters were collected.ResultsCompared with low baPWV group patients, high baPWV group patients were significant older (p<0.001) and more likely to have a high proportion of female gender (p=0.004) as well as previous CVD history (p=0.008). Serum albumin, pre-albumin levels and residual renal creatinine clearance (CCr) were significantly lower but the serum ferritin level was significantly higher in high baPWV group patients than in low baPWV group patients (all p<0.01). BaPWV was positively associated with age (r=0.534, p<0.001), Charlson comorbidity index (r=0.350, p<0.001) and serum ferritin level (r=0.340, p=0.001). Meanwhile, baPWV negatively correlated with serum albumin (r=−0.479, p<0.001), pre-albumin levels (r=−0.320, p=0.003) and residual renal CCr (r=−0.177, p=0.048). Age-adjusted partial correlation test found a significant correlation between baPWV and CRP (r=0.462, p<0.001). Multivariate regression analysis showed that baPWV was independently associated with age (p<0.001), serum albumin level (p=0.015), CRP (p=0.019) and residual renal CCr (p=0.045).ConclusionArterial stiffness, assessed by baPWV, had an independent correlation with age, serum albumin level, CRP level and residual renal CCr among PD patients in Macao.

Quaternary palaeoenvironmental oscillations drove the evolution of the Eurasian Carassius auratus complex (Cypriniformes, Cyprinidae)

AbstractAim We sought to reconstruct the spatio‐temporal genetic diversification in goldfish of the Carassius auratus complex, which is widely distributed in Eurasia, to test whether vicariance events or human‐mediated translocations best explained lineage divergence and genogeographical history.Location East Asia and the Oriental islands including Japan, the Ryukyus and Taiwan, and Europe, including Russia and the Czech Republic.Methods We reconstructed the matrilineal history of Eurasian goldfish using 1876 sequences from the partial mitochondrial DNA control region (426 bp) and 191 complete sequences of cytochrome b (1140 bp) from 67 localities representing most of the range of the species. Divergence times were estimated using a Bayesian Markov chain Monte Carlo approach based either on molecular clock data or on the fossil record. Genetic structure and the historical demography of populations were analysed using partial correlation tests and analyses of molecular variance.Results Three lineages had high levels of regional specificity. Lineages A and B from the main islands of Japan differed greatly from lineage C, which occurred on the mainland, Taiwan and the Ryukyus. Lineages A and B had late Pliocene origins. Six geographically constrained sublineages within lineage C had near‐simultaneous mid‐Pleistocene divergences.Main conclusions Genetic structure in the C. auratus complex appears to have been driven by palaeoenvironmental perturbations rather than human translocations. The disappearance of a land bridge in the Tsushima Strait around 3.0 Ma is responsible for the separation of Japanese and continental lineages; the estimated divergence time is 2.75–2.32 Ma. Fujian, China and Vietnam appear to have provided important refugia for the C. auratus complex during glaciation. After warm, moist summer monsoons intensified during the mid‐Pleistocene, goldfish are likely to have dispersed north‐eastwards to recolonize the Ryukyus via Taiwan and northwards to recolonize mainland China.

Analisis CSR Dan Kinerja Keuangan Studi Empiris Pada Perusahaan Yang Terdaftar Pada Indeks Sri Kehati

The objectives of this study are to analyze the difference and correlation between the corporate social performance and the corporate financial performance Companies in Indonesia, The sample population of this study is company listed in Indonesian Stock Exchange. sampling was used in this study, are 23 companies in SRI KEHATI Index The CSR score is measured by content analysis of corporate annual report . The data is tested by using partial correlation test to know the correlation between the corporate social performance and financial performance. The results of this study show that there no significant relation between financial performance at (t) year and CSR but found significant at tht (t+1) year. Managerial implications from this research will hopefully provide a new discourse for investor in considering the aspects that need to be taken into investments that are not to monetary measurements. this research hopes management company can provide the input on the importance of corporate social responsibility in terms of the overall strategic management to improve the company's financial and social performance and raise awareness of companies to conduct CSR activities.

Relationships between Plasma Osteopontin Levels and Cognitive Performances in Relapsing Multiple Sclerosis: Effect of Natalizumab Treatment (P04.099)

Objective: To assess the relationship between plasma Osteopontin (pOPN) levels and cognitive performances before and during 2 year Natalizumab (NTZ) treatment in Relapsing Multiple Sclerosis (RRMS) patients. Background Increased plasma and cerebrospinal fluid (CSF) OPN levels were reported in patients with MS, Alzheimer disease and HIV-associated dementia. A marked decline of CSF OPN levels during NTZ treatment has been recently described in RRMS patients. Design/Methods: Forty-three RRMS (33 F, mean age 34.3±10.4 years, mean disease duration 9.9±5.3 years, median EDSS [range]3.5[2.0-5.5]) scheduled for NTZ treatment and 22 age- and gender-matched Healthy Controls (HCs) were enrolled. pOPN levels were assessed by a commercial ELISA kit on plasma samples at baseline and every 6 months for 2 years. Cognitive performances were assessed, by the Brief Repeatable Battery, at baseline and every 12 months. A global Cognitive Impairment Index (CII) was calculated for each patient. The correlations between different parameters were evaluated through the Partial correlation test. Results: Baseline pOPN levels were significantly (Mann-Whitney test; p=.02) higher (65.13±22.91 ng/ml) in RRMS patients than in HCs (53.20±12.68). Cognitive impairment (failure≥3 tests) was detected in 27.9% of RRMS. In RRMS patients, baseline pOPN levels significantly correlated (r=.59, p=.004) with CII values (median 14; range 0-27). pOPN levels significantly (p=.036) decreased after 1(n=24; 56.19±17.63) and 2 (n=8; 36.87±8.71) years of NTZ treatment. Median CII significantly (p=.029) decreased during NTZ treatment to 9 (range 0-28) at year 1 and to 3.5 (range 0-18) at year 2. A significant correlation between the reduction of the CII and of the pOPN levels was found (r=.442; p=0.045) at year 1. Conclusions: these results suggest a possible role of OPN as a bridge protein between inflammation and neurodegeneration in RRMS and a beneficial effect of NTZ on cognitive performances partially related to a reduction of pOPN levels. Disclosure: Dr. Iaffaldano has nothing to disclose. Dr. Ruggieri has nothing to disclose. Dr. Viterbo has received personal compensation for activities with Biogen Idec and Novartis. Dr. Mastrapasqua has nothing to disclose. Dr. Paolicelli has received personal compensation for activities with Merck, Serono, Bayer Schering Pharma, and Biogen Idec. Dr. Lucchese has nothing to disclose. Dr. Trojano has received personal compensation for activities with Bayer Pharmaceuticals Corporation, Biogen Idec and Sanofi-Aventis Pharmaceuticals, Inc. as a consultant and/or speaker. Dr. Trojano has received research support from Merck & Co., Inc.

Executive Functions Predict the Success of Top-Soccer Players

While the importance of physical abilities and motor coordination is non-contested in sport, more focus has recently been turned toward cognitive processes important for different sports. However, this line of studies has often investigated sport-specific cognitive traits, while few studies have focused on general cognitive traits. We explored if measures of general executive functions can predict the success of a soccer player. The present study used standardized neuropsychological assessment tools assessing players' general executive functions including on-line multi-processing such as creativity, response inhibition, and cognitive flexibility. In a first cross-sectional part of the study we compared the results between High Division players (HD), Lower Division players (LD) and a standardized norm group. The result shows that both HD and LD players had significantly better measures of executive functions in comparison to the norm group for both men and women. Moreover, the HD players outperformed the LD players in these tests. In the second prospective part of the study, a partial correlation test showed a significant correlation between the result from the executive test and the numbers of goals and assists the players had scored two seasons later. The results from this study strongly suggest that results in cognitive function tests predict the success of ball sport players.

Choline metabolism biomarkers predict the risk of metabolic unfitness among young men

To test the hypothesis that plasma choline metabolism biomarkers, alone and together with genetic determinants of one carbon (1‐C) metabolism, predict metabolic unfitness associated with a lipid overload (i.e. obesity), a cross‐sectional analysis was conducted involving 249 Mexican American men with a median age of 22 y. Circulating concentrations of choline, betaine, folate, metabolic unfitness indicators (i.e. lipid panel and liver enzymes), and polymorphisms of 1‐C metabolizing genes (i.e. MTHFD1 G1958A) were assessed. Bivariate partial correlation tests and multivariate regression models were performed in data analysis. Plasma choline positively and plasma betaine negatively associated with body mass index (BMI) with lower plasma betaine observed in men whose BMI &gt; 25.8 kg/m2 (cohort median). In age‐ and BMI‐adjusted regression models, plasma betaine associated positively with serum HDL‐cholesterol. Further, plasma betaine associated negatively with serum alanine aminotransferase (ALT) among men with serum folate &lt; 14.5 ng/mL (cohort median) or among men with at least one copy of MTHFD1 1958A allele. In sum, these data demonstrate that choline metabolism markers predict the risk of metabolic unfitness and support the need to investigate the potential therapeutic benefits of choline/betaine on metabolic fitness.Grant Funding Source : NIH Grant #S06GM053933 and California Agriculture Research Initiative

THYROID FUNCTION TEST IMBALANCE IN EPILEPTIC CHILDREN UNDER ANTICONVULSIVE THERAPY

How to Cite this Article: Ravi Torkaman M, Amirsalari S, Saburi A. Thyroid Function Test Imbalance in Epileptic ChildrenUnder Anticonvulsive Therapy. Iranian Journal of Child Neurology 2012;6(1):43-44. Dear Editor, There have been many studies regarding the impact of antiepileptic drugs(AEDs) on thyroid function. There are some challenging scopes which must beconsidered for conducting the study adressing the focused question. “Which oneof the thyroid hormones is related to the AEDs consumption?”. Some studiesdemonstrated that there may be alterations in all thyroid function tests (T3, T4 andTSH) after antiepileptic therapy in children (1). Some studies concluded that longtermprescription of anticonvulsive medications resulted in a decline in serum T4levels, although it had no effect on serum TSH levels. However, changes in serumT3 level was challenging and it must be investigated further (2).There were some confounding factors which may interfere with the conclusion.One of them is the type of the study. There are various study plans for this purposesuch as cross-sectional, case-control, experimental, self-controlled cohort anddouble-blind randomized clinical trial studies. It seems that the proper protocol ofstudy for this propose is a double-blind randomized clinical trial study. By usingother designs, the authors cannot interpret the effect of AEDs on thyroid function;however, they can discuss the prevalence of thyroid hormone imbalance and thecoordination among T3, T4 and TSH.Moreover, one of the confounding factors is the thyroid binding globulin (TBG)effect. It has appeared that some of the AEDs may change the amount of TBGand in this way may affect the amount of thyroid hormones (3). Clonazepamand valproic acid do not have any enzyme inducing effects, but phenobarbital,carbamazepine, phenytoin and primidone may induce the hepatic enzyme (4-6). Therefore, it seems necessary to analyze each group of patients based on thetype of drug which is prescribed and also by using the free amount of thyroidhormones, the researcher will be able to exclude the TBG effect. In addition, ageis an important factor which should be considered. The epileptic patients showextra-thyroid adverse effects such as vitamin D and bone metabolism disordersdue to antiepileptic drugs (7). Other secondary clinical disorders which interactwith the thyroid metabolism should be considered and overruled in the study withthe mentioned proposal, especially in the older population.It appears that the confounding effect of the duration of AED intake mustbe adjusted regarding the children’s age using multivariate analysis such asregression model or partial correlation test. The etiological mechanism of serumconcentrations of thyroid hormone change by AEDs has not been clarified clearlyand besides, patients with a personal or family history of thyroid disorders mayprogress to overt thyroid hormone imbalance secondary to AED consumption (6). Therefore, it is suggested that the pure etiologicalmechanism of thyroid disorders due to AEDs shouldbe studied in such cases. Previous reports suggestedthat return to normal of all parameters was observedafter withdrawal of anticonvulsive therapy and thisreversibility of the thyroid hormone imbalance may bea clue for further investigations in order to study thepatho-physiologic mechanism of this disorder (6).Recently, new pharmaceutical drugs have beensuccessfully used for epileptic patients. It is expectedthat the therapeutic role of these new medications willbecome more prominent in these patients in the futureand future studies should be focused on their adverseeffects. Disclosures: None.

Ecological Study of Community-Level Factors Associated With Chronic Mountain Sickness in the Young Male Chinese Immigrant Population in Tibet

BackgroundChronic mountain sickness (CMS) is a complex medical and public health problem that seriously affects highland immigrants. This study investigated relationships between community-level factors and CMS.MethodsIn this ecological study, data on age- and ethnicity-standardized CMS rates, community factors, and controlling variables were obtained from 2009–2010 surveys of 108 Chinese highland military units. Associations among variables were examined using correlation tests, analyses of covariance, and logistic regression.ResultsThe rate of CMS ranged from 1.25% to 36.58% (mean: 14.65%, standard deviation: 8.15%) among military units. Partial correlation tests indicated that medicine expenditure was strongly negatively correlated with CMS (r = −0.267, P = 0.005). Analyses of covariance indicated that communities with oxygen-generating systems had lower CMS rates (F = 9.780, P = 0.002), whereas urban location (F = 5.442, P = 0.022) and construction duty (F = 4.735, P = 0.011) were associated with higher CMS rates. The multiple logistic model showed that medicine expenditure (OR = 0.897, P = 0.022), oxygen-generating system (available vs unavailable: OR = 0.827, P = 0.020), community type (urban vs rural: OR = 1.228, P = 0.019), and occupation (construction vs logistics: OR = 1.240, P = 0.029) were significantly associated with CMS.ConclusionsWe identified community-level, health-related factors that were associated with CMS among young male immigrants. To alleviate the burden of CMS in these highland immigrant populations, further investment should be made in medicine and oxygen-generating systems, and preventive interventions should be implemented among construction workers. Further research should investigate the effects of urbanization on CMS development.

Investigation of thealteration of gray matter volume in children with mental retardation with the optimalvoxel-based morphometry

：Objective To detectbrain structural difference between children with unexplained mental retardation andchildren with typically normal development. Methods The high-resolution magnetic MRimaging were obtained from 21 children with unexplained mental retardation and 30age-matched control children without intellectual disabilities. Voxel-based morphometryanalysis with an optimization of spatial segmentation and normalization procedures wereapplied to compare differences of gray matter volume between the two groups. The total andregional gray matter volume were compared between the two groups with independent t test.Meanwhile, correlation was conducted to analyze the relationship between the total graymatter volume and intelligence quotient (IQ) with partial correlation test. Results Thetotal gray matter volume was significantly increased in the mental retardation children[(1. 012 ±0. 079) × 106 mm3]in relative to the controls [(0. 956 ± 0. 059) × 106 mm3,t = - 2. 80, P ＜ 0. 05]. Compared tocontrols,children with unexplained mental retardation showed significantly increased graymatter volume in different regions, including the bilateral thalami, the bilateralsuperior frontal gyri, the bilateral gyri rectus, the bilateral temporal poles, the rightinferior frontal gyrus, right parahippocampal gyrus and the right cerebellum. Nocorrelation was detected between the total gray matter volume and IQ in children withmental retardation (r = 0. 078 ,P ＞ 0. 05). Conclusions VBM would detect the gray matterabnormalities that were not founded in routine MR scanning. The increase of gray mattervolume in the frontal-thalamus network might indicate the delayed maturation of the braindevelopment. This might be one of the causations of mental retardation in children. Key words: Mental retardation; Magnetic resonance imaging; Brain; Child

The neural basis of central proprioceptive processing in older versus younger adults: An important sensory role for right putamen

Our sense of body position and movement independent of vision (i.e., proprioception) relies on muscle spindle feedback and is vital for performing motor acts. In this study, we first sought to elucidate age-related differences in the central processing of proprioceptive information by stimulating foot muscle spindles and by measuring neural activation with functional magnetic resonance imaging. We found that healthy older adults activated a similar, distributed network of primary somatosensory and secondary-associative cortical brain regions as young individuals during the vibration-induced muscle spindle stimulation. A significant decrease in neural activity was also found in a cluster of right putamen voxels for the older age group when compared with the younger age group. Given these differences, we performed two additional analyses within each group that quantified the degree to which age-dependent activity was related to (1) brain structure and (2) a behavioral measure of proprioceptive ability. Using diffusion tensor imaging, older (but not younger) adults with higher mean fractional anisotropy were found to have increased right putamen neural activity. Age-dependent right putamen activity seen during tendon vibration was also correlated with a behavioral test of proprioceptive ability measuring ankle joint position sense in both young and old age groups. Partial correlation tests determined that the relationship between elderly joint position sense and neural activity in right putamen was mediated by brain structure, but not vice versa. These results suggest that structural differences within the right putamen are related to reduced activation in the elderly and potentially serve as biomarker of proprioceptive sensibility in older adults.

Domicile-related carbon monoxide poisoning in cold months and its relation with climatic factors

Background Many studies have identified strong correlations between winter months and acute, unintentional carbon monoxide (CO) poisoning. In this study, we aimed to investigate the incidence pattern of acute domicile-related CO poisoning in Beijing and its relation with climatic factors. Methods Data on CO poisoning were collected from the emergency medical service system during August 1, 2005, to July 31, 2007, in Beijing. Variations of the monthly and seasonal distribution of CO poisoning occurrences were examined with χ 2 testing. Climatic data including temperature, barometric pressure, humidity, wind speed, and visibility were obtained from the Beijing Meteorological Bureau. Correlations between the occurrence of CO poisoning and mean of each meteorological parameter spanning 3 days were analyzed with partial correlation test, with related parameters controlled. Results Significant differences were found among the cases occurring each month of the year ( P < .001). The monthly caseload reached the peak and the nadir in January and in September, respectively. During the cold period, 3331 patients were recorded, accounting for 88.4% of the total cases of the 2-year study period. Among the 5 climatic parameters, only temperature had a significant inverse correlation with the occurrence of CO poisoning ( P < .001, r = –0.467). Conclusions The incidences of CO poisoning were highest during winter, particularly during the time period when charcoal or coal use for indoor heating would be most prevalent in Beijing.

THE X-RAY ENERGY DEPENDENCE OF THE RELATION BETWEEN OPTICAL AND X-RAY EMISSION IN QUASARS

We develop a new approach to the well-studied anti-correlation between the optical-to-X-ray spectral index, alpha_ox, and the monochromatic optical luminosity, l_opt. By cross-correlating the SDSS DR5 quasar catalog with the XMM-Newton archive, we create a sample of 327 quasars with X-ray S/N > 6, where both optical and X-ray spectra are available. This allows alpha_ox to be defined at arbitrary frequencies, rather than the standard 2500 Angstroms and 2 keV. We find that while the choice of optical wavelength does not strongly influence the alpha_ox-l_opt relation, the slope of the relation does depend on the choice of X-ray energy. The slope of the relation becomes steeper when alpha_ox is defined at low (~ 1 keV) X-ray energies. This change is significant when compared to the slope predicted by a decrease in the baseline over which alpha_ox is defined. The slopes are also marginally flatter than predicted at high (~ 10 keV) X-ray energies. Partial correlation tests show that while the primary driver of alpha_ox is l_opt, the Eddington ratio correlates strongly with alpha_ox when l_opt is taken into account, so accretion rate may help explain these results. We combine the alpha_ox-l_opt and Gamma -L_bol/L_Edd relations to naturally explain two results: 1) the existence of the Gamma-l_x relation as reported in Young et al. (2009) and 2) the lack of a Gamma-l_opt relation. The consistency of the optical/X-ray correlations establishes a more complete framework for understanding the relation between quasar emission mechanisms. We also discuss two correlations with the hard X-ray bolometric correction, which we show correlates with both alpha_ox and Eddington ratio. This confirms that an increase in accretion rate correlates with a decrease in the fraction of up-scattered disk photons.

Association of heart rate recovery after exercise with indices of obesity in healthy, non-obese adults

We aimed at determining whether body mass index (BMI), waist circumference (WC), and waist-to-hip ratio (WHR) are associated with heart rate recovery (HRR) and to demonstrate which of the three indices of obesity, is the strongest predictor of HRR in apparently healthy non-obese adults. Three hundred and twenty-five subjects aged 18-66 years participated in the study. Anthropometric indices were measured, and subjects performed cycle ergometer exercise at 75-85% maximum heart rate. Heart rate (HR) was measured during the last minute of exercise and in the first minute of post-exercise recovery. A partial correlation test and a multiple linear regression analysis, after adjusting for age and peak oxygen uptake indicated that the best predictors of HRR were BMI in males and WHR in females. The present data suggest that, HRR is independently related to indices of obesity-BMI, WC, and WHR and strengthen the usefulness of these anthropometric indices in predicting cardiovascular risks. In addition, the findings suggest that BMI in men and WHR in women best express the relationship between obesity and cardiovascular risks.