The Jurassic Laberge Group in the Whitehorse Trough of the Canadian Cordillera: Using Detrital Mineral Geochronology and Thermochronology to Investigate Tectonic Evolution

The Laberge Group is an Early to Middle Jurassic sequence of mostly siliciclastic sedimentary rocks that were deposited in a marginal marine environment in the northern Canadian Cordillera. It forms a long narrow belt with a total thickness of 3–4 km extending for more than 600 km across southern Yukon and northwestern British Columbia. These sedimentary rocks overlap the Yukon-Tanana, Stikinia and Cache Creek terranes that form the main components of the Intermontane superterrane. The Laberge Group contains a record of the erosion of some of these terranes, and also offers some constraints on the timing of their amalgamation and accretion to the Laurentian margin. The Laberge Group was deposited with local unconformity on the Late Triassic Stuhini Group (in British Columbia) and correlative Lewes River Group (in Yukon), both of which are volcanic-rich, and assigned to the Stikinia terrane. The Laberge Group is in turn overlain by Middle Jurassic to Cretaceous clastic rocks, including the Bowser Lake Group in BC and the Tantalus Formation in Yukon. Clast compositions and detrital zircon populations within the Laberge Group and between it and these bounding units indicate major shifts in depositional environment, basin extent and detrital sources from Late Triassic to Late Jurassic. During the Early Jurassic clast compositions in the Laberge Group shifted from sediment- and volcanic-dominated to plutonic-dominated, and detrital zircon populations are dominated by grains that yield ages that approach or overlap their inferred depositional ages. This pattern is consistent with progressive dissection and unroofing of (an) active arc(s) to eventually expose Triassic to Jurassic plutonic suites. Detrital rutile and muscovite data from the Laberge Group indicate rapid cooling and then exhumation of adjoining metamorphic rocks during the Early Jurassic, allowing these to contribute detritus on a more local scale. The most likely source for such metamorphic detritus is within the Yukon-Tanana terrane, and its presence in the Laberge Group may constrain the timing of amalgamation and accretion of the Yukon-Tanana and Stikinia terranes. Thermochronological data also provide new insights into the evolution of the Laberge Group basin. Results from the U–Th/(He) method on detrital apatite suggest that most areas experienced post-depositional heating to 60°C or more, whereas U–Th/(He) results from detrital zircon show that heating to more than 200°C occurred on a more local scale. In detail, Laberge Group cooling and exhumation was at least in part structurally controlled, with more strongly heated areas situated in the footwall of an important regional fault system. The thermochronological data are preliminary, but they suggest potential to eventually constrain the kinematics and timing of inversion across the Laberge Group basin and may also have implications for its energy prospectivity. In summary, the Laberge Group is a complex package of sedimentary rocks developed in an active, evolving tectonic realm, and many questions remain about the details of its sources and evolution. Nevertheless, the available information demonstrates the potential of combined geochronological and thermochronological methods applied to detrital minerals to unravel links between regional tectonics, basin development and clastic sedimentation.Le groupe de Laberge est une séquence du Jurassique inférieur à moyen composée principalement de roches sédimentaires silicoclastiques qui se sont déposées dans un milieu margino-marin, dans le nord de la Cordillère canadienne. Il forme une longue ceinture étroite d'une épaisseur totale de 3 à 4 km s'étendant sur plus de 600 km à travers le sud du Yukon et le nord-ouest de la Colombie-Britannique. Ces roches sédimentaires chevauchent les terranes Yukon-Tanana, Stikinia et Cache Creek qui forment les principales composantes du superterrane Intermontagneux. Le groupe de Laberge contient un enregistrement de l'érosion de certains de ces terranes, et offre également certaines contraintes sur la datation de leur amalgamation et de leur accrétion à la marge laurentienne. Le groupe de Laberge a été déposé avec une discordance locale sur le groupe de Stuhini du Trias supérieur (en Colombie-Britannique) et le groupe corrélatif de Lewes River (au Yukon), tous deux riches en volcans et attribués au terrane de Stikinia. Le groupe de Laberge est à son tour recouvert de roches clastiques du Jurassique moyen à Crétacé, comprenant le groupe de Bowser Lake en Colombie-Britannique et la formation de Tantalus au Yukon. Les compositions de clastes et les populations de zircons détritiques au sein du groupe de Laberge et entre celui-ci, et ces unités limitrophes indiquent des changements majeurs dans l'environnement de dépôt, l'étendue du bassin et les sources détritiques du Trias supérieur jusqu’au Jurassique supérieur. Au cours du Jurassique inférieur, les compositions des clastes du groupe de Laberge sont passées d'une prédominance sédimentaire et volcanique à une prédominance plutonique, et les populations de zircons détritiques sont dominées par des grains qui donnent des âges qui se rapprochent ou chevauchent l’âge présumé de leur déposition. Ce modèle est cohérent avec la dissection progressive et le dévoilement d'un ou plusieurs arcs actifs pour éventuellement exposer les suites plutoniques du Trias au Jurassique. Les données sur le rutile détritique et la muscovite du groupe de Laberge indiquent un refroidissement rapide puis une exhumation des roches métamorphiques adjacentes au cours du Jurassique inférieur, permettant à celles-ci d’ajouter des débris à une échelle plus locale. La source la plus probable de ces débris métamorphiques se trouve dans le terrane Yukon-Tanana, et sa présence dans le groupe de Laberge peut apporter des contraintes sur la datation de l'amalgamation et de l'accrétion des terranes Yukon-Tanana et Stikinia. Les données thermo-chronologiques apportent également de nouveaux éclairages sur l'évolution du bassin du groupe de Laberge. Les résultats de la méthode U–Th/(He) sur l'apatite détritique suggèrent que la plupart des régions ont été soumises à des conditions de température post-dépôt de 60°C ou plus, tandis que les résultats U–Th/(He) sur zircon détritique montrent que des conditions de température de plus de 200° C se sont produites à une échelle plus locale. Dans le détail, le refroidissement et l'exhumation du groupe de Laberge étaient au moins en partie structurellement contrôlés, avec des régions plus fortement chauffées situées dans le mur d'un important système de failles régionales. Les données thermo-chronologiques sont préliminaires, mais elles suggèrent un potentiel pour éventuellement contraindre la cinématique et le moment de l'inversion à travers le bassin du groupe de Laberge et peuvent également avoir des implications sur sa capacité énergétique.En résumé, le groupe de Laberge est un ensemble complexe de roches sédimentaires développées dans un domaine tectonique actif et en évolution, et de nombreuses questions demeurent quant aux détails de ses sources et de son évolution. Néanmoins, les informations disponibles démontrent le potentiel de la combinaison des méthodes géochronologiques et thermo-chronologiques appliquées aux minéraux détritiques pour démêler les liens entre la tectonique régionale, le développement du bassin et la sédimentation clastique

Supporting the object-oriented database on the Kernel Database System

If a single operating system can support multitudes of different programming languages and data structures, a database system can support a variety of data models and data languages. In this thesis, a Kernel Database System (KDS) supporting classical data models and data languages (i.e., hierarchical, network, relational, and functional) is used to support a demonstration object oriented data model and data language. This thesis extends previous research by accommodating an object-oriented-data-model-and-language interface in the KDS. Consequently, the research shows that it is feasible to use the KDS to support modem data models and languages as well as classical ones. This thesis details the KDS design, Insert operation, and Display function. This thesis also details how to implement modifications to the Test-Interface so that the KDS can support the object-oriented database. This thesis proves complex data structures in an object-oriented data model can be realized using an attribute-based data model which is the kernel data model of the KDS. Second, it details how the KDS is designed showing why no changes needed to be made to the KDS to implement the object-oriented toy database. Third, it argues the advantages of using a KDS in the database-system design. The KDS design produces savings in costs from compatability, reduced training, expandability, and software reuse.http://archive.org/details/supportingobject1094535152NANAU.S. Navy (U.S.N.) author.;Korean Army author

Recovery from repeated on-court tennis sessions: Combining cold-water immersion, compression, and sleep interventions

To investigate the effects of combining cold-water immersion (CWI), full-body compression garments (CG), and sleep-hygiene recommendations on physical, physiological, and perceptual recovery after 2-a-day on-court training and match-play sessions. Methods: In a crossover design, 8 highly trained tennis players completed 2 sessions of on-court tennis-drill training and match play, followed by a recovery or control condition. Recovery interventions included a mixture of 15 min CWI, 3 h of wearing full-body CG, and following sleep-hygiene recommendations that night, while the control condition involved postsession stretching and no regulation of sleeping patterns. Technical performance (stroke and error rates), physical performance (accelerometry, countermovement jump [CMJ]), physiological (heart rate, blood lactate), and perceptual (mood, exertion, and soreness) measures were recorded from each on-court session, along with sleep quantity each night. Results: While stroke and error rates did not differ in the drill session (P > .05, d .05, d > 0.90). Although accelerometry values did not differ between conditions (P > .05, d .05, d = 0.90). Furthermore, CWI and CG resulted in faster postsession reductions in heart rate and lactate and reduced perceived soreness (P > .05, d > 1.00). In addition, sleep-hygiene recommendations increased sleep quantity (P > .05, d > 2.00) and maintained lower perceived soreness and fatigue (P 2.00). Conclusions: Mixed-method recovery interventions (CWI and CG) used after tennis sessions increased ensuing time in play and lower-body power and reduced perceived soreness. Furthermore, sleep-hygiene recommendations helped reduce perceived soreness. © 2014 Human Kinetics, Inc

Prevalence of hoarding disorder: A systematic review and meta-analysis

Currently there is uncertainty concerning the prevalence of Hoarding Disorder (HD) due to methodological issues in the evidence base. Estimates have widely ranged from between 1.5% and 6% of the general population. This systematic review and meta-analysis therefore aimed to summarise and reliably estimate the prevalence of HD by employing strict inclusion criteria and using studies with sufficiently large samples. A systematic literature search was conducted to identify all relevant prevalence studies. Inclusion criteria were studies that reported working age adult HD prevalence rates and had sample sizes of at least 1009 participants. Eleven studies met criteria (n = 53,378), had low risk of bias and were originally based in developed countries. A random effects meta-analysis was then conducted, with subgroup moderator analysis and meta-regression. The pooled estimated prevalence for HD was 2.5% (CI 1.7–3.6%) and subgroup analyses revealed that prevalence rates were similar for both males and females. Guidance on the manner in which HD is assessed in future prevalence studies is provided and the clinical implications of the results discussed

Exploring emotions and cognitions in hoarding: a Q-methodology analysis

Background: The cognitions and emotions of people prone to hoarding are key components of the dominant cognitive behavioural model of hoarding disorder. Aims: This study sought to use Q-methodology to explore the thoughts and feelings of people that are prone to hoarding, to identify whether distinct clusters of participants could be found. Method: A 49-statement Q-set was generated following thematic analysis of initial interviews (n = 2) and a review of relevant measures and literature. Forty-one participants with problematic hoarding met various study inclusion criteria and completed the Q-sort (either online or offline). A by-person factor analysis was conducted and subsequent participant clusters compared on psychometric measures of mood, anxiety, hoarding and time taken on the online task as proxy for impulsivity. Results: Four distinct participant clusters were found constituting 34/41 (82.92%) of the participants, as the Q-sorts of n = 7 participants failed to cluster. The four clusters found were ‘overwhelmed’ (n = 11 participants); ‘aware of consequences’ (n = 13 participants); ‘object complexity’ (n = 6 participants) and ‘object–affect fusion’ (n = 4 participants). The clusters did not markedly differ with regard to hoarding severity, anxiety, depression or impulsivity. Conclusions: Whilst the participant clusters reflect extant research evidence, they also reveal significant heterogeneity and so prompt the need for further research investigating emotional and cognitive differences between people prone to hoarding

A descriptive analysis of internal and external loads for elite-level tennis drills

Purpose: Planning tennis sessions accentuating physical development requires an understanding of training load (TL). The aims were to describe the external and internal TL of drills and analyze relationships between ratings of perceived exertion (RPE), TL, and other measures. Methods: Fourteen elite-level junior tennis athletes completed 259 individual drills. Six coaches helped devise classifications for all drills: recovery/defensive, open pattern, accuracy, 2-on-1 open, 2-on-1 net play, closed technical, point play, and match play. Notational analysis on stroke and error rates was performed postsession. Drill RPE and mental exertion were collected postdrill, while heart rate (HR) was recorded continuously. Results: Recovery/defensive, open pattern, and point play were significantly greater than closed technical drills (P .05) between categories. Substantial correlations existed for drill RPE and TL with mental exertion (r > .62) for several categories. TL was substantially correlated with total strokes (r > .65), while HR and stroke and error rates were in slight to moderate agreement with RPE and TL (r < .51). Conclusions: Recovery/defensive drills are highest in physiological stress, making them ideal for maximizing physicality. Recovery/defensive drills compromised training quality, eliciting high error rates. In contrast, 2-on-1 net-play drills provided the lowest error rates, potentially appropriate for error-amelioration practice. Open-pattern drills were characterized by significantly higher stroke rates, suggesting congruence with high-repetition practice. Finally, with strong relationships between physical and mental perception, mental exertion may complement currently used monitoring strategies (TL and RPE). © 2014 Human Kinetics, Inc

A comparison of the perceptual and technical demands of tennis training, simulated match play, and competitive tournaments

© 2016 Human Kinetics, Inc. Purpose: High-performance tennis environments aim to prepare athletes for competitive demands through simulated-match scenarios and drills. With a dearth of direct comparisons between training and tournament demands, the current investigation compared the perceptual and technical characteristics of training drills, simulated match play, and tournament matches. Methods: Data were collected from 18 high-performance junior tennis players (gender: 10 male, 8 female; age 16 ± 1.1 y) during 6 ± 2 drill-based training sessions, 5 ± 2 simulated match-play sessions, and 5 ± 3 tournament matches from each participant. Tournament matches were further distinguished by win or loss and against seeded or nonseeded opponents. Notational analysis of stroke and error rates, winners, and serves, along with rating of perceived physical exertion (RPE) and mental exertion was measured postsession. Results: Repeated-measures analyses of variance and effect-size analysis revealed that training sessions were significantly shorter in duration than tournament matches (P .05; d = 1.26, d = 1.05, respectively). Mental exertion in training was lower than in both simulated match play and tournaments (P >.05; d = 1.10, d = 0.86, respectively). Stroke rates during tournaments exceeded those observed in training (P .05, d < 0.80). Conclusions: Training in the form of drills or simulated match play appeared to inadequately replicate tournament demands in this cohort of players. Coaches should be mindful of match demands to best prescribe sessions of relevant duration, as well as internal (RPE) and technical (stroke rate) load, to aid tournament preparation

Comparison of athlete-coach perceptions of internal and external load markers for elite junior tennis training

Purpose: To investigate the discrepancy between coach and athlete perceptions of internal load and notational analysis of external load in elite junior tennis. Methods: Fourteen elite junior tennis players and 6 international coaches were recruited. Ratings of perceived exertion (RPEs) were recorded for individual drills and whole sessions, along with a rating of mental exertion, coach rating of intended session exertion, and athlete heart rate (HR). Furthermore, total stroke count and unforced-error count were notated using video coding after each session, alongside coach and athlete estimations of shots and errors made. Finally, regression analyses explained the variance in the criterion variables of athlete and coach RPE. Results: Repeated-measures analyses of variance and interclass correlation coefficients revealed that coaches significantly (P < .01) underestimated athlete session RPE, with only moderate correlation (r = .59) demonstrated between coach and athlete. However, athlete drill RPE (P = .14; r = .71) and mental exertion (P = .44; r = .68) were comparable and substantially correlated. No significant differences in estimated stroke count were evident between athlete and coach (P = .21), athlete notational analysis (P = .06), or coach notational analysis (P = .49). Coaches estimated significantly greater unforced errors than either athletes or notational analysis (P < .01). Regression analyses found that 54.5% of variance in coach RPE was explained by intended session exertion and coach drill RPE, while drill RPE and peak HR explained 45.3% of the variance in athlete session RPE. Conclusion: Coaches misinterpreted session RPE but not drill RPE, while inaccurately monitoring error counts. Improved understanding of external- and internal-load monitoring may help coach-athlete relationships in individual sports like tennis avoid maladaptive training. © 2014 Human Kinetics, Inc