Similar Covariance Research Articles

Decadal Covariability of the Northern Wintertime Land Surface Temperature and Atmospheric Circulation

Abstract The decadal covariability of northern wintertime land surface temperature and 500-hPa geopotential anomalies is examined using the National Centers for Environmental Prediction–National Center for Atmospheric Research and the Twentieth-Century Reanalyses over the twentieth century and a 996-yr preindustrial climate simulation from the Canadian Earth System Model. Based on the reanalysis data, the covariability is dominated by two leading maximum covariance analysis (MCA) modes. MCA1 is characterized by temperature anomalies over most of Canada, the eastern United States, Mexico, and Eurasian mid- to high latitudes, accompanied by anomalies of opposite sign elsewhere over northern landmasses. MCA2 features temperature anomalies over most of North America, Eurasia, and Greenland with opposite anomalies elsewhere. In the upper troposphere the synoptic vorticity fluxes reinforce the anomalous circulation, while in the lower troposphere advection by the anomalous mean flow offsets the eddy forcing and maintains the decadal temperature perturbation. The MCA1-associated variability has a broad spectrum over decadal–interdecadal time scales, while the MCA2-related variability has a significant power peak around 20 yr. The change of temperature and geopotential trends around 1990 tends to be a decadal-scale shift in winter and has significant features of the leading mode of the decadal covariability. The climate model has broadly similar decadal covariability, including the leading MCA patterns as well as the temporal evolution of the patterns. The decadal temperature and geopotential anomalies primarily covary with the North Atlantic Oscillation but also with the variability of the North Pacific index, while the Southern Oscillation index variability tends to be the least important predictor for the northern decadal temperature and geopotential anomalies.

Clustered Treatment Assignments and Sensitivity to Unmeasured Biases in Observational Studies

Clustered treatment assignment occurs when individuals are grouped into clusters prior to treatment and whole clusters, not individuals, are assigned to treatment or control. In randomized trials, clustered assignments may be required because the treatment must be applied to all children in a classroom, or to all patients at a clinic, or to all radio listeners in the same media market. The most common cluster randomized design pairs 2S clusters into S pairs based on similar pretreatment covariates, then picks one cluster in each pair at random for treatment, the other cluster being assigned to control. Typically, group randomization increases sampling variability and so is less efficient, less powerful, than randomization at the individual level, but it may be unavoidable when it is impractical to treat just a few people within each cluster. Related issues arise in nonrandomized, observational studies of treatment effects, but in this case one must examine the sensitivity of conclusions to bias from nonrandom selection of clusters for treatment. Although clustered assignment increases sampling variability in observational studies, as it does in randomized experiments, it also tends to decrease sensitivity to unmeasured biases, and as the number of cluster pairs increases the latter effect overtakes the former, dominating it when allowance is made for nontrivial biases in treatment assignment. Intuitively, a given magnitude of departure from random assignment can do more harm if it acts on individual students than if it is restricted to act on whole classes, because the bias is unable to pick the strongest individual students for treatment, and this is especially true if a serious effort is made to pair clusters that appeared similar prior to treatment. We examine this issue using an asymptotic measure, the design sensitivity, some inequalities that exploit convexity, simulation, and an application concerned with the flooding of villages in Bangladesh.

A new dynamic approach for statistical optimization of GNSS radio occultation bending angles for optimal climate monitoring utility

AbstractGlobal Navigation Satellite System (GNSS)‐based radio occultation (RO) is a satellite remote sensing technique providing accurate profiles of the Earth's atmosphere for weather and climate applications. Above about 30 km altitude, however, statistical optimization is a critical process for initializing the RO bending angles in order to optimize the climate monitoring utility of the retrieved atmospheric profiles. Here we introduce an advanced dynamic statistical optimization algorithm, which uses bending angles from multiple days of European Centre for Medium‐range Weather Forecasts (ECMWF) short‐range forecast and analysis fields, together with averaged‐observed bending angles, to obtain background profiles and associated error covariance matrices with geographically varying background uncertainty estimates on a daily updated basis. The new algorithm is evaluated against the existing Wegener Center Occultation Processing System version 5.4 (OPSv5.4) algorithm, using several days of simulated MetOp and observed CHAMP and COSMIC data, for January and July conditions. We find the following for the new method's performance compared to OPSv5.4: 1.) it significantly reduces random errors (standard deviations), down to about half their size, and leaves less or about equal residual systematic errors (biases) in the optimized bending angles; 2.) the dynamic (daily) estimate of the background error correlation matrix alone already improves the optimized bending angles; 3.) the subsequently retrieved refractivity profiles and atmospheric (temperature) profiles benefit by improved error characteristics, especially above about 30 km. Based on these encouraging results, we work to employ similar dynamic error covariance estimation also for the observed bending angles and to apply the method to full months and subsequently to entire climate data records.

Anatomic versus nonanatomic resection in cirrhotic patients with early hepatocellular carcinoma

Whether anatomic resection (AR) for hepatocellular carcinoma (HCC) can really confer a survival advantage over non-AR (NAR), especially for cirrhotic patients, remains unclear. Prospectively collected data of 543 cirrhotic patients in Child-Pugh class A submitted to AR (n = 228) versus NAR (n = 315) for early HCC in an Eastern (n = 269) and a Western (n = 274) surgical unit, were reviewed. To control for confounding variable distributions, a 1-to-1 propensity score match was applied to compare AR and NAR outcomes (n = 298). The 5-year recurrence-free and overall survivals of the 543 patients were 32.3% and 60.0%, respectively, without differences between the 2 centers (P = .635 and .479, respectively). AR conferred better overall and recurrence-free survival than NAR (P = .009 and .041, respectively), but NAR patients suffered from significantly worse hepatic dysfunction. After 1-to-1 match, AR (n = 149) and NAR (n = 149) patients had similar covariate distributions. In this matched sample, AR still conferred better recurrence-free survival over NAR (P = .044) but the beneficial effect of AR was limited to the reduction of early recurrence (<2 years) of poorly differentiated tumors and of tumors with microvascular invasion (P < .05), resulting in better overall survival (P = .018). In cirrhotic patients, AR for early HCC can lead to a lower early recurrence rate in tumors with unfavorable tumor features, whereas NAR will not worsen the recurrence rate in well/moderately differentiated tumors or in the absence of microvascular invasion.

Cardiovascular Risk in Rheumatoid Arthritis: Comparing TNF-α Blockade with Nonbiologic DMARDs

BackgroundElevated tumor necrosis factor (TNF)-α likely contributes to the excess cardiovascular risk observed in rheumatoid arthritis. We compared the cardiovascular risk in rheumatoid arthritis patients starting a TNF-α blocking agent versus a nonbiologic disease-modifying antirheumatic drug (nbDMARD). MethodsSubjects with rheumatoid arthritis participating in several different US insurance programs between 1998 and 2007 who received methotrexate were eligible. Those who added a TNF-α blocking agent were compared with subjects who added a nbDMARD in Cox regression models stratified by propensity score decile and adjusted for oral glucocorticoid dosage. We examined the composite cardiovascular end point of myocardial infarction, stroke, or coronary re-vascularization after 6 months. ResultsWe compared 8656 new users of a nbDMARD with 11,587 new users of a TNF-α blocking agent with similar baseline covariates. Incidence rates per 100 person-years for the composite cardiovascular end point were 3.05 (95% confidence interval [CI], 2.54-3.65) for nbDMARDs and 2.52 (95% CI, 2.12-2.98) for TNF-α blocking agents. The hazard ratio (HR) for the TNF-α blocking agent compared with nbDMARD carrying the first exposure forward was 0.80 (95%, CI 0.62-1.04), while the HR for the as-treated analysis was 0.71 (95% CI, 0.52-0.97). The potential cardiovascular benefit of TNF-α blocking agents was strongest among individuals ≥65 years of age (HR 0.52; 95% CI, 0.34 -0.77; P for interaction = 0.075). ConclusionAmong subjects with rheumatoid arthritis, TNF-α blocking agents may be associated with a reduced risk of cardiovascular events compared with an nbDMARD. Randomized controlled clinical trials should be considered to test this hypothesis.

Heart failure risk among patients with rheumatoid arthritis starting a TNF antagonist

BackgroundWhile heart failure (HF) is associated with elevations in tumor necrosis factor (TNF)α, several trials of TNF antagonists showed no benefit and possibly worsening of disease in those with known...

Health and Health Care Utilization among Obese and Diabetic Baby Boomers and Older Adults

Examine how sociodemographic, health, behavioral, and health care utilization factors are associated with being obese or having diabetes among baby boomers and older adults. Cross-sectional data were drawn from the 2007-2008 National Health and Nutrition Examination Survey. United States. A sample of 3439 baby boomers and older adults included (mean age, 62 years). Covariates included sociodemographics, health outcomes, behaviors, and inpatient and outpatient health care utilization. Multinomial logistic regression was used to explore which similar or different covariates were associated with different health states between baby boomers and older adults. Approximately 8% of baby boomers and 10% of older adults had the twin diagnoses of obesity and diabetes. Having both obesity and diabetes was more common among baby boomers and older adults who were African-American (odds ratio [OR] = 1.79, p = .029 for baby boomers; OR = 3.45, p < .001 for older adults), perceived their general health as fair/poor (OR = 7.67, p < .001; OR = 4.13, p < .001), and utilized outpatient care more often (OR = 8.28, p < .001; OR = 5.35, p = .004). Being obese only was observed less among baby boomers who were current smokers (OR = .45, p < .001), whereas it was observed more among older adults who were former smokers (OR = 1.25, p = .046). Having diabetes only was observed more among baby boomers who had hypertension (OR = 2.44, p = .01), whereas it was observed more among older adults who had very high cholesterol (OR = 2.31, p = .029). Identifying chronic disease risk factors during middle age is important for ameliorating further complications in later life. Knowing more about the correlates of obesity and diabetes among different age groups can help health care planners better target preventive health care services.

A conjugate study of mean winds and planetary waves employing enhanced meteor radars at Rio Grande, Argentina (53.8°S) and Juliusruh, Germany (54.6°N)

Two meteor radars with enhanced power and sensitivity and located at closely conjugate latitudes (54.6°N and 53.8°S) are employed for interhemispheric comparisons of mean winds and planetary wave structures at periods of ∼8 to 20 days. Our study uses data from June 2008 through May 2010 during which both radars provided nearly continuous wind measurements from ∼80 to 100 km. Monthly mean winds at 53.8°S exhibit a stronger westward zonal jet in spring and early summer at lower altitudes and no westward winds at higher altitudes. In contrast, westward mean winds of ∼5–10 ms−1 at 54.6°N extend to above 96 km during late winter and early spring each year. Equatorward mean winds extend approximately from spring to fall equinox at both latitudes with amplitudes of ∼5–10 ms−1. Meridional mean winds are more variable at both latitudes during fall and winter, with both poleward and equatorward monthly means indicating longer‐period variability. Planetary waves seen in the 2 day mean data are episodic and variable at both sites, exhibit dominant periodicities of ∼8–10 and 16–20 days and are more confined to late fall and winter at 54.6°N. At both latitudes, planetary waves in the two period bands coincide closely in time and exhibit similar horizontal velocity covariances that are positive (negative) at 54.6°N (53.8°S) during peak planetary wave responses.

Does Family Planning Reduce Infant Mortality? Evidence From Surveillance Data in Matlab, Bangladesh

Analyzing the effect of family planning on child survival remains an important issue but is not straightforward because of several mechanisms linking family planning, birth intervals, total fertility, and child survival. This study uses a dynamic model jointly explaining infant mortality, whether contraceptives are used after each birth, and birth intervals. Infant mortality is determined by the preceding birth interval and other covariates (such as socio-economic status).The decisions about using contraceptives after each birth are driven by similar covariates, survival status of the previous child, and the family’s gender composition. Birth spacing is driven by contraceptive use and other factors. We find favorable effects of contraceptive use, reducing infant deaths in second and higher order births. Because the mortality risks for first-borns is higher than for later births and contraceptive use reduces the number of higher order births, the net effect on the total infant mortality rate is small.

Bisphosphonate Therapy, Death, and Cardiovascular Events Among Female Patients With CKD: A Retrospective Cohort Study

Accelerated vascular calcification contributes to cardiovascular disease burden in patients with chronic kidney disease (CKD). We hypothesized that bisphosphonate therapy would reduce the risk of mortality and cardiovascular events in this population. Retrospective cohort study. Adult women with stage 3 or 4 CKD receiving primary care in a large rural integrated health care system in 2004-2010. Time-dependent exposure status based on outpatient prescription for any medication within the bisphosphonate class, obtained from electronic health records. Time to death and first cardiovascular event (composite of myocardial infarction, heart failure, or stroke). Data from 9,604 eligible female patients with CKD were analyzed; 3,234 were treated with bisphosphonate therapy. During a median follow-up of 3.9 (25th-75th percentile, 2.3-5.4) years, there were 286 versus 881 deaths and 206 versus 571 cardiovascular events (treated vs not-treated groups, respectively). In a multivariate Cox proportional hazard model, the adjusted HR for death (treated vs not treated) was 0.78 (95% CI, 0.67-0.91; P = 0.003). In Cox modeling adjusted for similar baseline covariates, treatment with bisphosphonates was not associated with a lower risk of the composite cardiovascular outcome (adjusted HR, 1.14; 95% CI, 0.94-1.39; P = 0.2). Residual confounding by unidentified factors, exclusion of male patients, and lack of information about longitudinal drug adherence. For female patients with CKD, treatment with bisphosphonates is associated with a lower risk of death, but not cardiovascular events. Confirmatory studies and investigations of potential causal mechanisms are warranted.

Influence of prior sunlight exposure on ICU mortality - does delirium play a role?

With interest we read the article by Castro and colleagues exploring the relationship between sunlight exposure and ICU mortality [1]. Interestingly, less daylight exposure prior to ICU admission was associated with a reduction in ICU mortality. While the authors mention the infl u ence of light on the development of delirium, it is also recognized that delirium is an independent risk factor for death [2-4]. However, the authors did not adjust for delirium. To determine whether sunlight exposure is still associated with ICU mortality when additional adjustments are made for delirium, we performed a similar retrospective cohort study on 2,623 patients admitted to ICUs of three large hospitals in the Netherlands. Th e 28-day photoperiod values were retrieved from weather stations in the vicinity of these hospitals from the Royal Dutch Meteorological Institute, including actual sunlight hours per day. Th e pre-illness photoperiod ranged from 37 to 301 hours. In total, 849 (32.4%) patients suff ered from delirium during their ICU admission and 200 (7.6%) patients died during their hospital stay. In a multivariate logistic regression analysis adjusting for similar covariates to the Castro group but now also including delirium, the cumulative 28-day photoperiod prior to ICU admission was not associated with in-hospital mortality (odds ratio = 1.001; 95% confi dence interval = 0.997 to 1.005). Naturally, our study population is smaller than that in Castro and colleagues’ study and therefore it would be interesting to know whether the reported relationship between sunlight exposure and outcome remains when delirium is added as a covariate. If this relationship does not remain, it could be determined whether delirium is a confounder or a mediator of mortality.

Safety of hepatic resection for colorectal metastases in the era of neo-adjuvant chemotherapy

The relationship between neo-adjuvant chemotherapy prior to hepatectomy in patients with resectable colorectal liver metastases and post-operative morbidity still has to be clarified. Data from 242 patients undergoing hepatectomy for colorectal liver metastases, judged resectable at first observation, were reviewed and their clinical outcome was related to neo-adjuvant chemotherapy (125 patients). Selection biases were outlined and properly handled by means of propensity score analysis. Post-operative death was 1.2% and morbidity 40.9%. Pre-operative chemotherapy was only apparently related to higher morbidity (P = 0.021): multivariate analysis identified extension of hepatectomy and intra-operative blood loss as independent prognostic variables (P < 0.05). Patients receiving and not receiving neo-adjuvant chemotherapy were significantly different for several covariates, including extension of hepatectomy (P = 0.049). After propensity score adjustment, 94 patients were identified as having similar covariate distribution (standardized differences <|0.1|) except for neo-adjuvant treatment (47 patients for each group). In this matched sample, mortality was similar and post-operative complications were only slightly higher (hazard ratio = 1.38) in treated patients. A significantly higher need for fluid replacement was only observed in patients receiving neo-adjuvant chemotherapy (P = 0.038). Neo-adjuvant chemotherapy showed a limited role in determining post-operative morbidity after hepatic resection and did not modify mortality.

Hormonal Contraception and HIV Risk

To the Editor: Recently, 2 analyses were published from the Hormonal Contraception and Risk of HIV Acquisition Study, a multicenter cohort study specifically designed to evaluate whether hormonal contraceptive use (depot-medroxyprogesterone acetate [DMPA] or combined oral contraceptives [COCs]) alters the risk of HIV acquisition among women.1,2 A detailed description of study participants and methods has been published elsewhere.1 The main study analysis used conventional Cox proportional hazard models with time-varying hormonal contraceptive exposure to adjust for demographic and sexual risk factors. This analysis showed little or no evidence of increased risk of HIV acquisition with either DMPA (hazard ratio = 1.25 [95% confidence interval = 0.89-1.78]) or COCs (0.99 [0.69-1.42]) compared with the nonhormonal group.1 A reanalysis using a marginal structural model (MSM) to accommodate hormonal-contraceptive exposure switching and confounding with the same set of demographic and sexual risk factors found evidence for an increased HIV acquisition risk associated with DMPA (1.48 [1.02-2.15]) but not COC use (1.19 [0.80-1.76]).2 MSMs can appropriately adjust for time-dependent confounding and selection bias using the inverse-probability-of-treatment weighting (IPTW).3 Nevertheless, the model relies on certain assumptions that either cannot be verified (eg, no unmeasured confounders) or could be problematic in the data from this study4 (eg, violation of the positivity assumption due to high association between pregnancy and hormonal contraceptive use). We conducted several sensitivity analyses to address the above concerns. First, we examined possible model misspecification in the marginal structural model by adding or removing suspected time-varying confounder(s). Second, we investigated the variability of hazard ratios estimated by MSM using a nonparametric bootstrapping procedure to obtain estimates from 1000 with replacement bootstrap samples.5 Finally, we explored possible violations of the positivity assumption when pregnancy status was included in the MSM analyses. We found a consistently larger effect of DMPA than COCs on HIV acquisition, compared with the nonhormonal group, across various analyses (Table). DMPA also appeared to have a larger effect with MSM analyses than with the conventional Cox model when similar covariates were included in analyses. Model misspecification can cause estimated hazard ratios to vary from 1.24 (0.85-1.80) to 1.51 (1.03-2.22) for DMPA, and from 1.00 (0.69-1.47) to 1.19 (0.80-1.76) for COCs.TABLE: Estimated Effect of HC Exposure on Time to HIV Acquisition in Hormonal Contraception and Risk of HIV Acquisition Study, Uganda and Zimbabwe, 1999-2004Compared with the results in Model 3 (the published results1), the bootstrapped estimates provided similar findings. We also note that the distributions of estimated weights were similar among MSM analyses that did not include pregnancy status; means and standard deviations were approximately 1 and 0.55, respectively, with reasonable ranges from about 0.01 to 2.64. However, when pregnancy status was included in the analysis, the distribution from untruncated weights clearly indicated the violation of positivity assumption because a large standard deviation (16.4) and a wide range of weights (from <0.01 to 3915) were observed. In general, the estimated effect becomes unstable and attenuated under that situation, with a large deviation of weights. The validity of the MSM analysis depends on the assumption that all confounders were measured and sufficient to adjust for confounding and selection biases. The causal effect estimates could be biased if these assumptions were incorrectly specified. In these analyses, we evaluated the potential issues of model specification and the positivity assumption. These findings parallel the results from a simulation study6 that found that inclusion of more confounders (even in the absence of complete control) resulted in a decrease in bias. This observation suggests that including all possible time-varying confounders in analyses may reduce bias, as long as no finite sample bias is introduced. In addition, because current pregnancy clearly violated the positivity assumption for computing IPTW in the estimation of the hormonal contraceptive effect on HIV acquisition, alternative modeling approaches (such as structural-nested-failure-time models) should be considered.7 Details on time-dependent confounder assessment and MSM specification are available in the eAppendix (https://links.lww.com/EDE/A514). Pai-Lien Chen Biostatistics Department FHI360 Research Triangle Park, NC [email protected] Stephen R. Cole Department of Epidemiology University of North Carolina Chapel Hill, NC Charles S. Morrison Clinical Sciences Department FHI360 Research Triangle Park, NC

Outcomes Among Black Patients With Stage II and III Colon Cancer Receiving Chemotherapy: An Analysis of ACCENT Adjuvant Trials

Among patients with resected colon cancer, black patients have worse survival than whites. We investigated whether disparities in survival and related endpoints would persist when patients were treated with identical therapies in controlled clinical trials. We assessed 14,611 patients (1218 black and 13,393 white) who received standardized adjuvant treatment in 12 randomized controlled clinical trials conducted in North America for resected stage II and stage III colon cancer between 1977 and 2002. Individual patient data on covariates and outcomes were extracted from the Adjuvant Colon Cancer ENdpoinTs (ACCENT) database. The endpoints examined in this meta-analysis were overall survival (time to death), recurrence-free survival (time to recurrence or death), and recurrence-free interval (time to recurrence). Cox models were stratified by study and controlled for sex, stage, age, and treatment to determine the effect of race. Kaplan-Meier estimates were adjusted for similar covariates to control for confounding. All statistical tests were two-sided. Black patients were younger than whites (median age, 58 vs 61 years, respectively; P < .001) and more likely to be female (55% vs 45%, respectively; P < .001). Overall survival was worse in black patients than whites (hazard ratio [HR] of death = 1.22, 95% confidence interval [CI] = 1.11 to 1.34, P < .001). Five-year overall survival rates for blacks and whites were 68.2% and 72.8%, respectively. When subsets defined by sex, stage, and age were analyzed, overall survival was consistently worse in black patients. Recurrence-free survival was worse in black patients than whites (HR of recurrence or death = 1.14, 95% CI = 1.04 to 1.24, P = .0045). Three-year recurrence-free survival rates in blacks and whites were 68.4% and 72.1%, respectively. In contrast, recurrence-free interval was similar in black and white patients (HR of recurrence = 1.08, 95% CI = 0.97 to 1.19, P = .15). Three-year recurrence-free interval rates in blacks and whites were 71.3% and 74.2%, respectively. Black patients with resected stage II and stage III colon cancer who were treated with the same therapy as white patients experienced worse overall and recurrence-free survival, but similar recurrence-free interval, compared with white patients. The differences in survival may be mostly because of factors unrelated to the patients' adjuvant colon cancer treatment.

Searching for the trigger of the active galactic nucleus quasi-periodic oscillation: 8 years of RE J1034+396

RE J1034+396 is one of the most extreme Narrow-line Seyfert 1s detected thus far, showing the only quasi-periodic oscillation (QPO) reliably detected in an Active Galactic Nucleus (AGN). Comparison with similar spectral and timing properties observed in the black hole X-ray binary (BHB) GRS 1915+105 suggests that RE J1034+396 is a super-Eddington accretor. A more complete understanding of the behaviour of RE J1034+396 can therefore lead to a unification of the accretion physics between such extreme AGN and super-Eddington BHBs. Here we report on our latest XMM-Newton observations of RE J1034+396, which no longer show the QPO, indicating that this source shows a non-stationary power-spectrum. We use spectral and temporal analysis across all five XMM-Newton observations of the source to probe the evolution of the object. The combination of the shape of the fractional variability with energy and the inferred velocity of absorbing material in the line-of-sight rules out an absorption-only method of creating the QPO. Instead the periodically changing absorption may be produced by the QPO causing a change in ionization state. We extend our analysis by including the covariance spectra which give much better signal to noise than an rms spectrum. These reveal a new aspect of the QPO, which is that there is also a small contribution from a soft component which is hotter than the soft excess seen in the mean spectrum. Folding the lightcurve on the QPO period shows that this component lags behind the hard X-rays. If this is due to re-processing then the lag corresponding to a light travel time across 30 R_g. Some of the remaining observations have similar energy spectra and covariance spectra, but none of them show a significant QPO, so we conclude that none of these features are the trigger for the appearance of the QPO in this object.

Genetic variation shapes protein networks mainly through non-transcriptional mechanisms.

Author SummaryThe level of protein produced by each gene corresponds approximately to the level of mRNA transcript produced by that gene: so high-abundance proteins, like those involved in protein synthesis, are represented by high-abundance transcripts, whereas low-abundance proteins, like those involved in signaling pathways, are represented by low-abundance transcripts. Furthermore, genetic variation can cause variation in transcript levels for the same gene between different individuals. These two observations have led to the assumption that inter-individual variation in transcript levels for any particular gene causes corresponding variation in protein levels. However, this need not be the case, because protein levels could be controlled not only by regulating transcript levels but also by regulating protein translation and stability. Because inter-individual variation in the levels of the transcript for any particular gene is typically less than 3-fold, rather than orders of magnitude, it is possible that the predominant cause of inter-individual variation in levels of any particular protein is transcription-independent regulation of protein levels. Here, we look in a genetically diverse population of 95 yeast strains at the genetic variation that leads in turn to variation in levels of 354 proteins that function within co-regulated networks. We find that the between-strain variation predominantly reflects transcription-independent mechanisms. If this result is typical of the proteome as a whole, it suggests that protein levels in genetically diverse populations cannot be accurately inferred from levels of their underlying transcripts.

THE QUANTITATIVE GENETICS OF INCIPIENT SPECIATION: HERITABILITY AND GENETIC CORRELATIONS OF SKELETAL TRAITS IN POPULATIONS OF DIVERGING FAVIA FRAGUM ECOMORPHS

Recent speciation events provide potential opportunities to understand the microevolution of reproductive isolation. We used a marker-based approach and a common garden to estimate the additive genetic variation in skeletal traits in a system of two ecomorphs within the coral species Favia fragum: a Tall ecomorph that is a seagrass specialist, and a Short ecomorph that is most abundant on coral reefs. Considering both ecomorphs, we found significant narrow-sense heritability (h(2) ) in a suite of measurements that define corallite architecture, and could partition additive and nonadditive variation for some traits. We found positive genetic correlations for homologous height and length measurements among different types of vertical plates (costosepta) within corallites, but negative correlations between height and length within, as well as between costosepta. Within ecomorphs, h(2) estimates were generally lower, compared to the combined ecomorph analysis. Marker-based estimates of h(2) were comparable to broad-sense heritability (H) obtained from parent-offspring regressions in a common garden for most traits, and similar genetic co-variance matrices for common garden and wild populations may indicate relatively small G × E interactions. The patterns of additive genetic variation in this system invite hypotheses of divergent selection or genetic drift as potential evolutionary drivers of reproductive isolation.

Effects of an Economic Recession on Leader Personality and General Mental Ability Scores

Economic recessions have wide-ranging implications for the workforce. The science and practice of industrial and organizational psychology are certainly not immune to those implications. The purpose of this study was to examine the effects of an economic recession on leader personality and general mental ability scores in three samples (nTime 1=564; nTime 2=581; nTime 3=281) of US bank employees. The samples differed primarily in level of unemployment in the general US economy (Time 1=4.67%; Time 2=7.77%; Time 3=9.77%) with samples matched on five branches located in cities throughout the United States. Internal consistency reliabilities and similar variances and covariances across samples were found to be statistically indistinguishable. However, statistically significantly higher personality scale means in the Time 2 and Time 3 samples were evidenced in comparison to the Time 1 sample. Additional analyses suggested that these mean differences would result in different percentages of individuals being selected at seven of nine selection ratios. Implications, limitations, and future research are discussed.

On the mechanism of interannual variability of the Irminger Water in the Labrador Sea

(IWT) in the NAOexperiment have 2-3 times smaller magnitude than in the NAO + experiment. The decadal variations in the strength of circulation in the NAO + experiment covaries negatively with SSTA1 and IWT anomalies. A similar covariability of these parameters is not found in the NAOsimulations. The results from the model experiment forced with the NCEP/NCAR reanalysis from 1958 to 2005 show a shift in the subpolar ocean response to the atmospheric variability in the early 1980s. The amplitude of quasi-decadal variability of the IWT and SSTA1 and their correlation are high after 1980 (r = 0.79) and weaker in the period between 1958 and 1980 (r = 0.1). The IWT after 1980 is well correlated (r = 0.67) to the subpolar gyre transport index (SPGI, defined as the minimum value of the annual mean anomaly of the model barotropic stream function). This correlation is weaker and negative (r = �0.09) in the period from 1958 to 1980. We explain this shift in the covariability of the SSTA1, IWT, and SPGI with the antisymmetric response of the SPG to atmospheric variations at decadal time scale under positive and negative NAO index. The NAO sign changed in the early 1980s from predominantly negative to positive phase. In the 1980s and 1990s the model SPGI variability follows closely the decadal variations of the NAO index with a delay of about 3 years. Similar covariability between the SPGI and the NAO and related negative covariance of SSTA1 and IWT with the SPGI are not observed in the model simulations of the period from 1958 to 1980.

A Product Partition Model With Regression on Covariates

We propose a probability model for random partitions in the presence of covariates. In other words, we develop a model-based clustering algorithm that exploits available covariates. The motivating application is predicting time to progression for patients in a breast cancer trial. We proceed by reporting a weighted average of the responses of clusters of earlier patients. The weights should be determined by the similarity of the new patient’s covariate with the covariates of patients in each cluster. We achieve the desired inference by defining a random partition model that includes a regression on covariates. Patients with similar covariates are a priori more likely to be clustered together. Posterior predictive inference in this model formalizes the desired prediction.We build on product partition models (PPM). We define an extension of the PPM to include a regression on covariates by including in the cohesion function a new factor that increases the probability of experimental units with similar covariates to be included in the same cluster. We discuss implementations suitable for any combination of continuous, categorical, count, and ordinal covariates.An implementation of the proposed model as R-package is available for download.