Adolescent Substance Use and Individual Beliefs That Drug Use Is Wrong: A Statewide Epidemiological Study.

OBJECTIVE: Informed by cognitive dissonance theory, the current study investigated the ability of youths' belief that drug use is wrong to predict likelihood of past year substance use abstinence as well as frequency of use at grades 8, 10, and 12. METHOD: Study analyses were executed from a statewide epidemiological survey of more than 125,000 youth using multi-group Zero-Inflated Poisson regression modeling. RESULTS: Personal belief that drug use is wrong demonstrated the largest magnitude of effect at each grade among the individual, family, and school-based factors under examination; this finding emerged with respect to predicting past year substance use abstinence as well as rates of substance use among individuals reporting past year use. Although differences across grades were evident for the magnitude of effect within various risk and protective factors, the rank ordering in magnitude of effect between factors was consistent across grades 8, 10, and 12. CONCLUSION: Current results underscore the salience of youths' belief that drug use is wrong in explaining likelihood of past year substance use at multiple time points during adolescence.Supplemental data for this article is available online at https://doi.org/10.1080/10826084.2022.2034877 .

Kinanthropometric Characteristic Comparisons of NCAA Division I Offensive and Defensive Linemen Spanning 8 Decades.

ABSTRACT: Jacobson, BH, Dawes, J, Smith, D, and Johnson, Q. Kinanthropometric characteristic comparisons of NCAA Division I offensive and defensive linemen spanning eight decades. J Strength Cond Res 36(12): 3404-3408, 2022-College football players have gained body mass, stature, and speed since the inception of the game. Of particular note is the body mass gain of NCAA Division I offensive linemen (OL) and defensive linemen (DL). The primary purpose of this study was to compare body mass and stature of OL and DL for each decade since 1950 and to subsequently compare speed using more recently available NFL Combine data to determine if the rates of gain have been consistent or is waning. Ten universities were randomly chosen from the "Power Five" conferences based on the prominence of their football programs. Recorded data included players' body mass, stature, and available 40 yd times. For each team, 8 OL and 8 DL were chosen, totaling 80 OL and 80 DL. Results indicated that body mass increased significantly ( p < 0.05) for both OL and DL (57.9 and 54.4%, respectively). However, the rate of weight gain for either OL or DL was not linear. Both OL and DL consistently increased in height from 1950 with OL and DL increasing 12.7 cm (5.0 in) and 11.4 cm (4.7 in), respectively. In addition, 40 yd times have improved over the 3 available decades (2000-2020). The 2020 times were significantly faster than the 2000 for both OL and DL. These findings may have profound implications related to player safety. The overall increases in body mass of linemen in combination with greater speed may result in have devastating consequences to the human body in a contact/collision sport such as football. Indeed, new rules are being considered to reduce debilitating injures.

Age-related gene expression changes in lumbar spinal cord: Implications for neuropathic pain.

Clinically, pain has an uneven incidence throughout lifespan and impacts more on the elderly. In contrast, preclinical models of pathological pain have typically used juvenile or young adult animals to highlight the involvement of glial populations, proinflammatory cytokines, and chemokines in the onset and maintenance of pathological signalling in the spinal dorsal horn. The potential impact of this mismatch is also complicated by the growing appreciation that the aged central nervous system exists in a state of chronic inflammation because of enhanced proinflammatory cytokine/chemokine signalling and glial activation. To address this issue, we investigated the impact of aging on the expression of genes that have been associated with neuropathic pain, glial signalling, neurotransmission and neuroinflammation. We used qRT-PCR to quantify gene expression and focussed on the dorsal horn of the spinal cord as this is an important perturbation site in neuropathic pain. To control for global vs region-specific age-related changes in gene expression, the ventral half of the spinal cord was examined. Our results show that expression of proinflammatory chemokines, pattern recognition receptors, and neurotransmitter system components was significantly altered in aged (24-32 months) versus young mice (2-4 months). Notably, the magnitude and direction of these changes were spinal-cord region dependent. For example, expression of the chemokine, Cxcl13, increased 119-fold in dorsal spinal cord, but only 2-fold in the ventral spinal cord of old versus young mice. Therefore, we propose the dorsal spinal cord of old animals is subject to region-specific alterations that prime circuits for the development of pathological pain, potentially in the absence of the peripheral triggers normally associated with these conditions.

Provision of consumer health information in Alberta's Rural Public Libraries.

BACKGROUND: Access to health services is a major challenge in many rural communities within Canada. Rural public libraries can serve as centres for health resources. OBJECTIVE: The aim of this exploratory study was to analyse the manner in which Alberta's rural libraries provide health information to their patrons. METHODS: A questionnaire including closed ended and open ended questions was sent to the 285 rural libraries across the Canadian province of Alberta. Descriptive statistics and thematic analysis techniques were used for the data analysis. RESULTS: The findings indicate that in three quarters of Alberta's rural libraries, about 10% of requests for assistance were related to health issues. The provision of health information in these libraries is hampered by the lack of Internet, private space for reference interviews, and staff and volunteer training. Library staff members were inexperienced in conducting reference transactions and reported lacking confidence in meeting patrons' needs and ethical standards. DISCUSSION: Addressing these challenges will require the recruitment of more qualified librarians in rural library systems, possibly through incentive measures, and a comprehensive education and training programme for both staff and volunteers combined with the necessary resource support for the rural libraries. CONCLUSION: When human and material resources are adequate, rural libraries can contribute to improving the health literacy of their communities.

Temporally specific miRNA expression patterns in the dorsal and ventral striatum of addiction-prone rats.

MicroRNAs (miRNAs) within the ventral and dorsal striatum have been shown to regulate addiction-relevant behaviours. However, it is unclear how cocaine experience alone can alter the expression of addiction-relevant miRNAs within striatal subregions. Further, it is not known whether differential expression of miRNAs in the striatum contributes to individual differences in addiction vulnerability. We first examined the effect of cocaine self-administration on the expression of miR-101b, miR-137, miR-212 and miR-132 in nucleus accumbens core and nucleus accumbens shell (NAcSh), as well as dorsomedial striatum and dorsolateral striatum (DLS). We then examined the expression of these same miRNAs in striatal subregions of animals identified as being 'addiction-prone', either immediately following self-administration training or following extinction and relapse testing. Cocaine self-administration was associated with changes in miRNA expression in a regionally discrete manner within the striatum, with the most marked changes occurring in the nucleus accumbens core. When we examined the miRNA profile of addiction-prone rats following self-administration, we observed increased levels of miR-212 in the dorsomedial striatum. After extinction and relapse testing, addiction-prone rats showed significant increases in the expression of miR-101b, miR-137, miR-212 and miR-132 in NAcSh, and miR-137 in the DLS. This study identifies temporally specific changes in miRNA expression consistent with the engagement of distinct striatal subregions across the course of the addiction cycle. Increased dysregulation of miRNA expression in NAcSh and DLS at late stages of the addiction cycle may underlie habitual drug seeking, and may therefore aid in the identification of targets designed to treat addiction.

Can Squat Jump Performance Differentiate Starters vs. Nonstarters in Division I Female Soccer Players?

Magrini, MA, Colquhoun, RJ, Sellers, JH, Conchola, EC, Hester, GM, Thiele, RM, Pope, ZK, and Smith, DB. Can squat jump performance differentiate starters vs. nonstarters in division I female soccer players? J Strength Cond Res 32(8): 2348-2355, 2018-Although soccer is predominately an endurance sport, high velocity movements may be an important indicator of athletic success. The purpose of this investigation was to establish whether squat jumps (SJs) can differentiate starters from nonstarters with a female collegiate division I soccer team. Eighteen female division I soccer athletes were separated into 2 groups: 9 starters (age: 19.5 ± 1.0; mass = 64.8 ± 11.5 kg; height = 167.5 ± 7.7 cm; games started = 18.2 ± 4.7; and minutes played = 1633.8 ± 478.2 minutes) and 9 nonstarters (age: 19.4 ± 1.4 years; mass = 63.3 ± 4.2 kg; height = 164.7 ± 6.8 cm; games started 0.7 ± 1.3; and minutes played 158.2 ± 269.3 minutes). Each athlete performed 3 maximal SJs at a starting knee angle of 110° without arm swing. Each participant's SJ height, mean power (MP), peak power (PP), mean velocity (MV), and peak velocity (PV) were measured during each attempt by a linear position transducer. No statistically significant differences (p ≥ 0.05) in MP and PP between the starters and nonstarters were observed. However, starters performed significantly better than nonstarters in SJ height (p = 0.002), MV (p = 0.025), and PV (p = 0.015). In addition, SJ height was strongly correlated with MV (r = 0.628) and PV (r = 0.647). These findings suggest that SJ height, MV, and PV may be important variables for discriminating differences between starters and nonstarters in division I female soccer athletes and a strong indicator of explosive performance.

Predictability of European 2016/2017.

Winter 2016/2017 was one of the driest on record for central Europe and the United Kingdom. This was the result of blocked atmospheric circulation with high pressure centred over North-West Europe dominating the winter mean circulation pattern. Using large ensembles of simulated winters, we find that the observed winter 2016/2017 circulation was very similar in pattern and strength to the circulation associated with the top 10% of driest Central European winters. Here, we explore whether seasonal forecasts were able to predict this circulation pattern. Despite the fact that the observed circulation anomaly did not project on to the North Atlantic Oscillation (NAO), we find that forecasts starting in November did predict a high-pressure anomaly over North-Western Europe. We use two independent data sets, and methods, to probe the drivers of this circulation pattern. We find evidence for a Rossby Wave propagating out of the tropical Atlantic where there were anomalous local rainfall anomalies. This case study is another example of real-time seasonal forecast skill for Europe and provides evidence for predictability beyond the NAO pattern.

[Benefits of integrated care delivery system for heart failure: A case study of Intermountain Healthcare (USA)]. / Bénéfices de la prise en charge intégrée de l'insuffisance cardiaque : l'exemple d'Intermountain Healthcare (États-Unis).

BACKGROUND: Among chronic diseases, heart failure is a top public health priority both in France and in the United States. If progress is possible in France, the experience from Intermountain Healthcare (IH), in the United States can be a source of significant experimentations. AIM: To identify the teaching of the clinical integration of the specialists in the field of heart failure with the primary care sector which could be useful in France. METHODS: This research is based on the qualitative analysis of data resulting from the work between experts, of bibliographical research, and of some groupings by item corresponding to the objectives of the Triple Aim from the Institute for Healthcare Improvement (IHI). RESULTS: The program of the integrated care delivery system for heart failure of Intermountain Healthcare reaches the objectives of the Triple Aim from the IHI, that is to say, the enhancement of the health of the population, improving quality of care and the satisfaction of the user, and the reduction of the cost of care. This program also enhances the Chronic Care Model by integrating a team of specialists in the field of heart failure, building up a pluridisciplinary team focused on the need of both the patients and their families. This creates a multidisciplinary care delivery system for heart failure which is global, protocolized, stratified, planned and followed. The prevention and the ambulatory care integrating the specialized care of second stage to the care of first stage are developed. The users and their families are co-responsible for their health. The systematic evaluation is based on the specific indicators. DISCUSSION: This program improves the effectiveness of care while improving organizational efficiency resulting in savings for IH Health Plan (SelectHealth). It also enhances the equality of access to better healthcare and health for the entire population.

Caution in interpreting FTIR/ATR spectral intensity values.

We discuss and demonstrate why FTIR/ATR spectra can only be calibrated in wavelength, not intensity, for comparison with other data sets at present. This is because the intensity calibration must remove the instrument response function. To address this problem, we suggest a possible approach.

Influences of Interelectrode Distance and Innervation Zone on Electromyographic Signals.

The purpose of the present study was to examine the effects of electrode placements centered over and offset from the innervation zone (IZ) with different interelectrode distances (IED) on the time and frequency domain parameters of the electromyographic (EMG) signal during a fatiguing submaximal, isometric workout. 11 adults performed an isometric leg extension muscle action at 50% maximal voluntary isometric contraction (MVIC) to exhaustion. Electromyographic amplitude and frequency parameters were determined from electrode placements with different IED centered over, at proximal offset, at distal offset, and away from the IZ at 10, 50, and 100% of the time to exhaustion using an electrode array. There were greater absolute EMG amplitude and lower absolute EMG frequency for electrode placements over and offset from the IZ, but lower absolute EMG amplitude over than offset from the IZ regardless of IED at each time-point during the time to exhaustion. The absolute EMG frequency values were affected by the location relative to the IZ and IED of the electrode placements, and were greater for distal offset vs. proximal offset electrode placements at each time-point. Normalization of the EMG amplitude and EMG frequency values to MVIC eliminated differences due to IED and electrode placements during the fatiguing workout.

Robust warming of the global upper ocean.

A large ( approximately 10(23) J) multi-decadal globally averaged warming signal in the upper 300 m of the world's oceans was reported roughly a decade ago and is attributed to warming associated with anthropogenic greenhouse gases. The majority of the Earth's total energy uptake during recent decades has occurred in the upper ocean, but the underlying uncertainties in ocean warming are unclear, limiting our ability to assess closure of sea-level budgets, the global radiation imbalance and climate models. For example, several teams have recently produced different multi-year estimates of the annually averaged global integral of upper-ocean heat content anomalies (hereafter OHCA curves) or, equivalently, the thermosteric sea-level rise. Patterns of interannual variability, in particular, differ among methods. Here we examine several sources of uncertainty that contribute to differences among OHCA curves from 1993 to 2008, focusing on the difficulties of correcting biases in expendable bathythermograph (XBT) data. XBT data constitute the majority of the in situ measurements of upper-ocean heat content from 1967 to 2002, and we find that the uncertainty due to choice of XBT bias correction dominates among-method variability in OHCA curves during our 1993-2008 study period. Accounting for multiple sources of uncertainty, a composite of several OHCA curves using different XBT bias corrections still yields a statistically significant linear warming trend for 1993-2008 of 0.64 W m(-2) (calculated for the Earth's entire surface area), with a 90-per-cent confidence interval of 0.53-0.75 W m(-2).

Relationship Between Selected Strength and Power Assessments to Peak and Average Velocity of the Drive Block in Offensive Line Play.

Jacobson, BH, Conchola, EC, Smith, DB, Akehi, K, and Glass, RG. Relationship between selected strength and power assessments to peak and average velocity of the drive block in offensive line play. J Strength Cond Res 30(8): 2202-2205, 2016-Typical strength training for football includes the squat and power clean (PC) and routinely measured variables include 1 repetition maximum (1RM) squat and 1RM PC along with the vertical jump (VJ) for power. However, little research exists regarding the association between the strength exercises and velocity of an actual on-the-field performance. The purpose of this study was to investigate the relationship of peak velocity (PV) and average velocity (AV) of the offensive line drive block to 1RM squat, 1RM PC, the VJ, body mass (BM), and body composition. One repetition maximum assessments for the squat and PC were recorded along with VJ height, BM, and percent body fat. These data were correlated with PV and AV while performing the drive block. Peal velocity and AV were assessed using a Tendo Power and Speed Analyzer as the linemen fired, from a 3-point stance into a stationary blocking dummy. Pearson product analysis yielded significant (p ≤ 0.05) correlations between PV and AV and the VJ, the squat, and the PC. A significant inverse association was found for both PV and AV and body fat. These data help to confirm that the typical exercises recommended for American football linemen is positively associated with both PV and AV needed for the drive block effectiveness. It is recommended that these exercises remain the focus of a weight room protocol and that ancillary exercises be built around these exercises. Additionally, efforts to reduce body fat are recommended.

Time Course of Changes in Neuromuscular Parameters During Sustained Isometric Muscle Actions.

Smith, CM, Housh, TJ, Herda, TJ, Zuniga, JM, Camic, CL, Bergstrom, HC, Smith, DB, Weir, JP, Hill, EC, Cochrane, KC, Jenkins, NDM, Schmidt, RJ, and Johnson, GO. Time course of changes in neuromuscular parameters during sustained isometric muscle actions. J Strength Cond Res 30(10): 2697-2702, 2016-The objective of the present study was to identify the time course of changes in electromyographic (EMG) and mechanomyographic (MMG) time and frequency domain parameters during a sustained isometric muscle action of the leg extensors at 50% maximal voluntary isometric contraction. The EMG and MMG signals were measured from the vastus lateralis of 11 subjects to identify when motor unit activation strategies changed throughout the sustained isometric muscle action. The EMG amplitude (muscle activation) had a positive linear relationship (p = 0.018, r = 0.77) that began to increase at the initiation of the muscle action and continued until task failure. Electromyographic frequency (motor unit action potential conduction velocity) and MMG frequency (global motor unit firing rate) had negative quadratic relationships (p = 0.002, R = 0.99; p = 0.015, R = 0.94) that began to decrease at 30% of the time to exhaustion. The MMG amplitude (motor unit activation) had a cubic relationship (p = 0.001, R = 0.94) that increased from 10 to 30% of the time to exhaustion, then decreased from 40 to 70% of the time to exhaustion, and then markedly increased from 70% to task failure. The time course of changes in the neuromuscular parameters suggested that motor unit activation strategies changed at approximately 30 and 70% of the time to exhaustion during the sustained isometric muscle action. These findings indicate that the time course of changes in neuromuscular responses provide insight into the strategies used to delay the effects of fatigue and are valuable tools for quantifying changes in the fatiguing process during training programs or supplementation research.

Effects of field storage method on E. coli concentrations measured in storm water runoff.

Storm water runoff is increasingly assessed for fecal indicator organisms (e.g., Escherichia coli, E. coli) and its impact on contact recreation. Concurrently, use of autosamplers along with logistic, economic, technical, and personnel barriers is challenging conventional protocols for sample holding times and storage conditions in the field. A common holding time limit for E. coli is 8 h with a 10 °C storage temperature, but several research studies support longer hold time thresholds. The use of autosamplers to collect E. coli water samples has received little field research attention; thus, this study was implemented to compare refrigerated and unrefrigerated autosamplers and evaluate potential E. coli concentration differences due to field storage temperature (storms with holding times ≤24 h) and due to field storage time and temperature (storms >24 h). Data from 85 runoff events on four diverse watersheds showed that field storage times and temperatures had minor effects on mean and median E. coli concentrations. Graphs and error values did, however, indicate a weak tendency for higher concentrations in the refrigerated samplers, but it is unknown to what extent differing die-off and/or regrowth rates, heterogeneity in concentrations within samples, and laboratory analysis uncertainty contributed to the results. The minimal differences in measured E. coli concentrations cast doubt on the need for utilizing the rigid conventional protocols for field holding time and storage temperature. This is not to say that proper quality assurance and quality control is not important but to emphasize the need to consider the balance between data quality and practical constraints related to logistics, funding, travel time, and autosampler use in storm water studies.

Adjuvant chemotherapy for stage III colon cancer: relative dose intensity and survival among veterans.

BACKGROUND: Given the paucity of information on dose intensity, the objective of this study is to describe the use of adjuvant chemotherapy for stage III colon cancer, focusing on relative dose intensity (RDI), overall survival (OS) and disease-free survival (DFS). METHODS: Retrospective cohort of 367 patients diagnosed with stage III colon cancer in 2003-2008 and treated at 19 VA medical centers. Kaplan-Meier curves summarize 5-year OS and 3-year DFS by chemotherapy regimen and RDI, and multivariable Cox proportional hazards regression was used to model these associations. RESULTS: 5-fluorouracil/leucovorin (FU/LV) was the most commonly initiated regimen in 2003 (94.4%) and 2004 (62.7%); in 2005-2008, a majority of patients (60%-74%) was started on an oxaliplatin-based regimen. Median RDI was 82.3%. Receipt of >70% RDI was associated with better 5-year OS (p < 0.001) and 3-year DFS (P = 0.009) than was receipt of ≤70% RDI, with 5-year OS rates of 66.3% and 50.5%, respectively and 3-year DFS rates of 66.1% and 52.7%, respectively. In the multivariable analysis of 5-year OS, oxaliplatin + 5-FU/LV (versus 5-FU/LV) (HR = 0.55; 95% CI = 0.34-0.91), >70% RDI at the first year (HR = 0.58; 95% CI = 0.37-0.89) and married status (HR = 0.66; 95% CI = 0.45-0.97) were associated with significantly decreased risk of death, while age ≥75 (versus 55-64) (HR = 2.06; 95% CI = 1.25-3.40), Charlson Comorbidity Index (HR = 1.17; 95% CI = 1.06-1.30), T4 tumor status (versus T1/T2) (HR = 5.88; 95% CI = 2.69-12.9), N2 node status (HR = 1.68; 95% CI = 1.12-2.50) and bowel obstruction (HR = 2.32, 95% CI = 1.36-3.95) were associated with significantly increased risk. Similar associations were observed for DFS. CONCLUSION: Patients with stage III colon cancer who received >70% RDI had improved 5-year OS. The association between RDI and survival needs to be examined in studies of adjuvant chemotherapy for colon cancer outside of the VA.

Effects of neuromuscular fatigue on electromechanical delay of the leg extensors and flexors in young men and women.

INTRODUCTION: We examined the effects of neuromuscular fatigue on volitional electromechanical delay (EMD) of leg extensors and flexors between genders. METHODS: Twenty-one men and 20 women performed 2 maximal voluntary contractions (MVCs), followed by intermittent isometric contractions of leg extensors and flexors using a 0.6 duty cycle (6-s contraction, 4-s relaxation) at 50% of MVC until volitional fatigue was achieved. MVCs were again performed at 0, 7, 15, and 30 min post-fatigue. RESULTS: EMD was greater compared with baseline at all post-fatigue time phases for the leg flexors (P = 0.001-0.007), while EMD was greater at Post0, Post15 and Post30 (P = 0.001-0.023) for the leg extensors. EMD was also greater for leg extensors compared with leg flexors only at Post0. CONCLUSION: No differential gender-related fatigue effects on EMD were shown. There were different fatigue-induced responses between leg extensors and flexors, with leg extensors exhibiting higher EMD immediately post-fatigue.

Earth's energy imbalance since 1960 in observations and CMIP5 models.

Observational analyses of running 5 year ocean heat content trends (Ht) and net downward top of atmosphere radiation (N) are significantly correlated (r ∼ 0.6) from 1960 to 1999, but a spike in Ht in the early 2000s is likely spurious since it is inconsistent with estimates of N from both satellite observations and climate model simulations. Variations in N between 1960 and 2000 were dominated by volcanic eruptions and are well simulated by the ensemble mean of coupled models from the Fifth Coupled Model Intercomparison Project (CMIP5). We find an observation-based reduction in N of - 0.31 ± 0.21 W m-2 between 1999 and 2005 that potentially contributed to the recent warming slowdown, but the relative roles of external forcing and internal variability remain unclear. While present-day anomalies of N in the CMIP5 ensemble mean and observations agree, this may be due to a cancelation of errors in outgoing longwave and absorbed solar radiation. KEY POINTS: Observed maximum in ocean heat content trend in early 2000s is likely spuriousNet incoming radiation (N) reduced by 0.31 ± 0.21 W m-2 during the warming pausePresent-day estimates of N may contain opposing errors in radiative components.

Acute Postexercise Time Course Responses of Hypertrophic vs. Power-Endurance Squat Exercise Protocols on Maximal and Rapid Torque of the Knee Extensors.

The aim of this study was to examine the effects of a medium-intensity high-volume vs. explosive squat protocol on the postexercise time course responses of maximal and rapid strength of the knee extensors. Seventeen resistance-trained men (mean ± SD: age = 22.0 ± 2.6 years) performed maximal voluntary contractions (MVCs) of the knee extensors before and after performing a squat workout using either a low-intensity fast velocity (LIFV) (5 × 16 at 40% 1 repetition maximum) or a traditional high-intensity slow velocity (TISV) (5 × 8 at 80% 1RM) exercise protocol. For each MVC, peak torque (PT), peak rate of torque development (RTDpeak), absolute (RTDabs), and relative RTD (RTDnorm) at early (0-50 milliseconds) and late (100-200 milliseconds) phases of muscle contraction were examined at pre- (Pre) and post-exercise at 0, 7, 15, and 30 (Post0...30) minutes. There were no intensity × time interactions for any variables (p = 0.098-0.832). Peak torque was greater at Pre than Post0 and Post7 (p = 0.001-0.016) but was not greater than Post15 and Post30 (p = 0.010-0.189). RTDpeak and early absolute RTD (RTD50abs) were greater at Pre than all postexercise time phases (p = 0.001-0.050); however, later absolute RTD (RTD100-200abs) was only greater at Pre than Post0 and Post30 (p = 0.013-0.048). Early relative RTD (RTD50norm) was only higher at Pre compared with Post0 (p = 0.023), whereas no differences were observed for later relative RTD (RTD100-200norm) (p = 0.920-0.990). Low-intensity fast velocity and TISV squat protocols both yielded acute decreases in maximal and rapid strength capacities following free-weight squats, with rapid strength showing slower recovery characteristics than maximal strength.

Do seasonal-to-decadal climate predictions underestimate the predictability of the real world?

Seasonal-to-decadal predictions are inevitably uncertain, depending on the size of the predictable signal relative to unpredictable chaos. Uncertainties can be accounted for using ensemble techniques, permitting quantitative probabilistic forecasts. In a perfect system, each ensemble member would represent a potential realization of the true evolution of the climate system, and the predictable components in models and reality would be equal. However, we show that the predictable component is sometimes lower in models than observations, especially for seasonal forecasts of the North Atlantic Oscillation and multiyear forecasts of North Atlantic temperature and pressure. In these cases the forecasts are underconfident, with each ensemble member containing too much noise. Consequently, most deterministic and probabilistic measures underestimate potential skill and idealized model experiments underestimate predictability. However, skilful and reliable predictions may be achieved using a large ensemble to reduce noise and adjusting the forecast variance through a postprocessing technique proposed here.