STRATIGRAPHY AND SEDIMENTATION OF THE PRECAMBRIAN REVETT FORMATION, NORTHWEST MONTANA AND NORTHERN IDAHO

The Revett Formation of the Middle Proterozoic Belt Supergroup can be usefully divided into informal lower, middle, and upper members which can be correlated throughout the study area. The lower Revett is dominated by thick beds of clean, fine-grained quartzite which is most commonly flat-laminated or cross-stratified. The middle Revett is composed of thinly-laminated siltite and argillite with only occasional thin interbeds of clean quartzite. Laminae in the siltite are characteristically wavy and laterally discontinuous. The upper Revett comprises interstratified intervals tens of meters thick of both clean, fine-grained quartzite and thinly-laminated siltite-argillite. Quartzite beds in the Revett Formation are tabular and laterally persistent, and lack channels or lateral accretion surfaces. Unchannelized, laterally unconfined sheet-floods are interpreted as the major depositional mechanism. Paleocurrent trends indicate dominantly north-northeastward sediment transport. Regional stratigraphic trends support this interpretation. Lateral and distal variation in sheet-flood deposits are represented in stratigraphic sections by changing ratios of clean quartzite to siltite. Vertical sequences of thickening, thinning, or thickening then thinning of quartzite beds represent abandonment, progradation, or shifting of depositional lobes. Southward stratigraphic thickening in the upper Revett across the Jocko line, a proposed down-to-the-south syndepositional growth fault (Winston, 1982), is not abrupt enough to be clearly related to active faulting during deposition. A southward- thickening sediment wedge or structural displacement of thick next to thin stratigraphic sections may be better explanations of the observed thickness changes

Incorporating Road User Costs into Integrated Life-Cycle Cost Analyses for Infrastructure Sustainability: A Case Study on Sr-91 Corridor Improvement Project (Ca)

Life-cycle cost analysis (LCCA) is a decision-making tool that allows governing agencies the ability to assess several long-term alternative investment options. This paper presents a LCCA analysis process which integrates the Federal Highway Administration (FHWA) program, RealCost (a road user cost calculation program), the FHWA-endorsed Construction Analysis for Pavement Rehabilitation Strategies (CA4PRS) and Caltrans specific design tools (CalFP and CalAC), into the existing Caltrans LCCA process (a modified version of the FHWA LCCA process). In using tools backed by the FHWA and validated through previous agency use, the presented process has a potential to be replicated on urban corridor improvement projects across the US while aiding agencies in achieving economical sustainability throughout the infrastructure maintenance phases. This paper also fills the gap identified by Ozbay et al. in 2004, incorporating road user cost calculations into the LCCA process. Validation was achieved through the execution of the recently completed $1.4 B US California SR-91 Corridor Improvement Project. The SR-91 team used the presented tool to choose one of the two alternatives (maintain HOV SR-91 lane and add I-15 HOV lane using long-life Portland Cement Concrete Pavement or add Express Lane to SR-91 and I-15 using long-life Continuously Reinforced Concrete Pavement and Asphalt Concrete Pavement), equating to an estimated life-cost savings of$32 M.112Nsciessciscopu

Comparative Water Relations of Four Species of Upland Deciduous Trees along a Moisture Gradient

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Efectos de la salinidad sobre la gravedad específica y la viabilidad de huevos de una carpa norteamericana (Ciprinidae)

The influence of salinity on survival, specific gravity, and size of eggs of the endangered Hybognathus amarus (Rio Grande silvery minnow) was studied to provide insight into factors affecting their potential dispersal and fate. Under low salinity conditions egg specific gravity declined significantly in the first hour after spawning as the perivitelline space of the egg filled with water. Egg specific gravity achieved a minimum value approximately 1 h post-spawning and remained approximately constant until hatching, which occurred near 48 h post-spawning at 20°C. Specific gravity of the egg depended on the salinity of the water surrounding the egg: hardened eggs changed rapidly in diameter and specific gravity when exposed to water of higher salinity. Size and specific gravity of H. amarus eggs also differed when the eggs were incubated in different groundwater sources. Experiments indicated that calcium chloride saline solution had a greater effect on egg specific gravity and size than did solutions of sodium or potassium chlorides. Survival of H. amarus eggs declined sharply at salinity greater than 3 (practical salinity units, PSU) and was only 5% at a salinity of 8. Habitat restoration to benefit H. amarus should consider the salinity of habitats in which eggs incubate.El efecto de la salinidad sobre la supervivencia, gravedad específica y talla de los huevos del ciprínido puesto en peligro de extinción, Hybognathus amarus, fue estudiado para proporcionar información sobre los factores que afectan la dispersión y el destino de los huevos. Bajo condiciones de salinidad baja la gravedad específica del huevo disminuyó de forma significativa durante la primera hora después de la puesta, a medida que el espacio del perivitelino del huevo se fue llenando de agua. la gravedad específica del huevo alcanzó un valor mínimo 1 hora después de la puesta y quedó aproximadamente constante hasta eclosión, que ocurrió alrededor de 48 horas tras la puesta a 20˚C. la gravedad específica del huevo dependió de la salinidad del agua que le rodeaba. los huevos con corion endurecido cambiaron rápidamente en diámetro y gravedad específica cuando fueron expuestos a agua de salinidad más alta. El tamaño y la gravedad específica de los huevos de H. amarus también se diferenciaron cuando los huevos fueron incubados en diferentes fuentes de agua subterránea. Los experimentos indicaron que la solución salina del cloruro de calcio tuvo un mayor efecto sobre la gravedad específica del huevo que las soluciones de los cloruros del sodio o del potasio. Expuestos a soluciones de salinidad de más de 3 (PsU), la supervivencia de los huevos de H. amarus disminuyó claramente, bajando a sólo el 5% en la solución de 8. la restauración del hábitat con el objetivo de beneficiar a H. amarus debe considerar la salinidad de los hábitats en los cuales el huevo incuba

Mechanical Performance of Direct Restorative Techniques Utilizing Long Fibers for “Horizontal Splinting” to Reinforce Deep MOD Cavities-An Updated Literature Review

Excessive cavity preparation and root canal treatment leads to a weakened tooth structure with a lower resistance to fracture. Fiber reinforcement is frequently used to reinforce such teeth, and multiple fiber types and possible applications exist. Various methods for utilizing long fibers to internally splint the remaining cavity walls in the case of large mesio-occluso-distal (MOD) cavities have been proposed; however, no summary of their performance has been written up to now. Our study aims to review the available literature to evaluate and compare the mechanical performance of the different materials and methods utilized for horizontal splinting in large MOD cavities. Three independent authors performed a thorough literature search using PubMed, ScienceDirect, and Google Scholar up until January 2022. The authors selected in vitro studies that used long fibers placed horizontally in posterior teeth with large MOD cavities to reinforce these teeth. From 1683 potentially relevant articles, 11 publications met our inclusion criteria. Seven out of eleven studies showed that horizontal splinting with long fibers improved the fracture resistance of the restored teeth. Three articles showed no significant difference between the fracture resistance of the restored groups. Only one article reported a lower fracture resistance to the horizontally splinted group, compared to conventional direct composite restoration. Within the limitations of this review, evidence suggests that long fiber reinforcement could be used to improve the fracture resistance of heavily restored teeth.</p

Fracture behaviour of MOD restorations reinforced by various fibre-reinforced techniques - An in vitro study

PURPOSE: The aim was to evaluate the fracture resistance of various direct restorative techniques utilizing different fibre-reinforced materials for restoring deep class II. MOD cavities in molar teeth.MATERIAL AND METHODS: Two hundred forty intact mandibular third molars were randomly divided into twelve groups (n = 20). Except for the control group (G12), deep mesio-occluso-distal (MOD) cavities were prepared all other groups. After adhesive treatment and rebuilding the missing interproximal walls with composite, the specimen were restored with different fibres and a final occlusal layer of composite as follows: composite only (G1), short fibre-reinforced composite (SFRC) (G2), glass fibre net (GFN) on the base of the cavity bucco-lingually (BL) and SFRC (G3), SFRC and GFN on top of it BL (G4), SFRC and occlusal splinting with GFN (G5), GFN circumferentially and SFRC (G6), polyethylene fibres (PF) on the base of the cavity BL and composite (G7), composite and PF on top of it BL (G8), composite and occlusal splinting with PF (G9), PF circumferentially and composite (G10), transcoronal splinting with PF (G11). Fracture-resistance for the restored teeth were tested using universal-testing machine. Fracture thresholds and fracture patterns were measured and evaluated.RESULTS: The transcoronal splinting (G11) yielded the highest fracture resistance among the restored groups. Groups 1, 3 and 4 showed significantly lower fracture resistance values compared to intact teeth.CONCLUSION: Incorporating polyethylene or a combination of short and bidirectional glass fibres in certain positions in direct restorations seems to be able to restore the fracture resistance of sound molar teeth.</p

Exercise-Induced Protection Against Reperfusion Arrhythmia Involves Stabilization of Mitochondrial Energetics

Mitochondria influence cardiac electrophysiology through energy- and redox-sensitive ion channels in the sarcolemma, with the collapse of energetics believed to be centrally involved in arrhythmogenesis. This study was conducted to determine if preservation of mitochondrial membrane potential (ΔΨ(m)) contributes to the antiarrhythmic effect of exercise. We utilized perfused hearts, isolated myocytes, and isolated mitochondria exposed to metabolic challenge to determine the effects of exercise on cardiac mitochondria. Hearts from sedentary (Sed) and exercised (Ex; 10 days of treadmill running) Sprague-Dawley rats were perfused on a two-photon microscope stage for simultaneous measurement of ΔΨ(m) and ECG. After ischemia-reperfusion, the collapse of ΔΨ(m) was commensurate with the onset of arrhythmia. Exercise preserved ΔΨ(m) and decreased the incidence of fibrillation/tachycardia (P < 0.05). Our findings in intact hearts were corroborated in isolated myocytes exposed to in vitro hypoxia-reoxygenation, with Ex rats demonstrating enhanced redox control and sustained ΔΨ(m) during reoxygenation. Finally, we induced anoxia-reoxygenation in isolated mitochondria using high-resolution respirometry with simultaneous measurement of respiration and H(2)O(2). Mitochondria from Ex rats sustained respiration with lower rates of H(2)O(2) emission than Sed rats. Exercise helps sustain postischemic mitochondrial bioenergetics and redox homeostasis, which is associated with preserved ΔΨ(m) and protection against reperfusion arrhythmia. The reduction of fatal ventricular arrhythmias through exercise-induced mitochondrial adaptations indicates that mitochondrial therapeutics may be an effective target for the treatment of heart disease

Primary homework in England: the beliefs and practices of teachers in primary schools

This study examines teachers’ views about and practices in homework in primary schools, based on questionnaire data from 235 primary teachers and 19 in-depth interviews. Findings suggest that teachers prioritise contradictory goals and act in ways that support only some of these. Reading with parents is a universal form of homework and other homework focuses either on English or mathematics or takes a project-led approach. Integration of homework into class learning is problematic. Teachers are concerned about the possible effects of homework on educational inequality and questions are raised about teachers’ perceptions of homework as a signifier of good parenting