Seasonal proximate composition and food source comparisons of Dolly Varden char in the Kugururok River, Alaska

Thesis (M.S.) University of Alaska Fairbanks, 1996The Kugururok River on the Noatak River System is an important spawning tributary for Dolly Varden char (Salvelinus malma), an important subsistence resource, occur bycatch in commercial fisheries, and are the basis of a sport fishery. The feeding habits and energetic condition of two spawning run patterns in the Noatak River Drainage were studied. Isotope ratio analysis revealed a predominantly marine carbon and nitrogen composition in all adult char. No internal isotopic fractionations were found either between tissues or seasons in any tissue. Proximate analysis revealed patterns of lipid and protein utilization characteristic of periodic starvation in fishes. Significant shifts of energy between key tissues were noted during the production of gonads. Data suggest that energetic minimums must be reached at sea before char can enter freshwater and successfully spawn.National Park Servic

Ocean Acidification and Alaska

This presentation outlines research questions and existing information regarding key commercial fisheries and the potential impact of ocean acidification in Alaska. Presented to the Alaska Board of Fisheries in October 2019

Laser Guide Stars for Extremely Large Telescopes: Efficient Shack-Hartmann Wavefront Sensor Design using Weighted center-of-gravity algorithm

Over the last few years increasing consideration has been given to the study of Laser Guide Stars (LGS) for the measurement of the disturbance introduced by the atmosphere in optical and near-infrared astronomical observations from the ground. A possible method for the generation of a LGS is the excitation of the Sodium layer in the upper atmosphere at approximately 90 km of altitude. Since the Sodium layer is approximately 10 km thick, the artificial reference source looks elongated, especially when observed from the edge of a large aperture. The spot elongation strongly limits the performance of the most common wavefront sensors. The centroiding accuracy in a Shack-Hartmann wavefront sensor, for instance, decreases proportionally to the elongation (in a photon noise dominated regime). To compensate for this effect a straightforward solution is to increase the laser power, i.e. to increase the number of detected photons per subaperture. The scope of the work presented in this paper is twofold: an analysis of the performance of the Weighted Center of Gravity algorithm for centroiding with elongated spots and the determination of the required number of photons to achieve a certain average wavefront error over the telescope aperture.Comment: 10 pages, 14 figure

Validation of Acute Myocardial Infarction (AMI) in the FDA’s Mini-Sentinel Distributed Database

The Food and Drug Administration’s (FDA) Mini-Sentinel is a pilot program that aims to conduct active surveillance to detect and refine safety signals that emerge for marketed medical products. The purpose of this Mini-Sentinel AMI Validation project was to: (a) develop and design an abstraction and adjudication process to use when full text medical record review is required to confirm a coded diagnosis; and (b) to test this approach by validating a code algorithm for acute myocardial infarction (AMI)

CDK4/6 inhibitors induce replication stress to cause long-term cell cycle withdrawal

CDK4/6 inhibitors arrest the cell cycle in G1‐phase. They are approved to treat breast cancer and are also undergoing clinical trials against a range of other tumour types. To facilitate these efforts, it is important to understand why a cytostatic arrest in G1 causes long‐lasting effects on tumour growth. Here, we demonstrate that a prolonged G1 arrest following CDK4/6 inhibition downregulates replisome components and impairs origin licencing. Upon release from that arrest, many cells fail to complete DNA replication and exit the cell cycle in a p53‐dependent manner. If cells fail to withdraw from the cell cycle following DNA replication problems, they enter mitosis and missegregate chromosomes causing excessive DNA damage, which further limits their proliferative potential. These effects are observed in a range of tumour types, including breast cancer, implying that genotoxic stress is a common outcome of CDK4/6 inhibition. This unanticipated ability of CDK4/6 inhibitors to induce DNA damage now provides a rationale to better predict responsive tumour types and effective combination therapies, as demonstrated by the fact that CDK4/6 inhibition induces sensitivity to chemotherapeutics that also cause replication stress

Impacts of forestry planting on primary production in upland lakes from north-west Ireland

Planted forests are increasing in many upland regions world-wide, but knowledge about their potential effects on algal communities of catchment lakes is relatively unknown. Here the effects of afforestation were investigated using palaeolimnology at six upland lake sites in the north-west of Ireland subject to different extents of forest plantation cover (4-64% of catchment area). 210Pb dated sediment cores were analysed for carotenoid pigments from algae, stable isotopes of bulk carbon (δ13C) and nitrogen (δ15N), and C/N ratios. In lakes with >50% of their catchment area covered by plantations, there were two- to six-fold increases in pigments from cryptophytes (alloxanthin) and significant but lower increases (39-116%) in those from colonial cyanobacteria (canthaxanthin), but no response from biomarkers of total algal abundance (β-carotene). In contrast, lakes in catchments with <20% afforestation exhibited no consistent response to forestry practices, although all lakes exhibited fluctuations in pigments and geochemical variables due to peat cutting and upland grazing prior to forest plantation. Taken together, patterns suggest that increases in cyanobacteria and cryptophyte abundance reflect a combination of mineral and nutrient enrichment associated with forest fertilisation and organic matter influx which may have facilitated growth of mixotrophic taxa. This study demonstrates that planted forests can alter the abundance and community structure of algae in upland humic lakes of Ireland and Northern Ireland, despite long histories of prior catchment disturbance

Statistics Clinic

Do you have elevated pvalues? Is the data analysis process getting you down? Do you experience anxiety when you need to respond to criticism of statistical methods in your manuscript? You may be suffering from Insufficient Statistical Support Syndrome (ISSS). For symptomatic relief of ISSS, come for a free consultation with JSC biostatisticians at our help desk during the poster sessions at the HRP Investigators Workshop. Get answers to common questions about sample size, missing data, multiple testing, when to trust the results of your analyses and more. Side effects may include sudden loss of statistics anxiety, improved interpretation of your data, and increased confidence in your results

A Mouse Model of Huntington’s Disease Shows Altered Ultrastructure of Transverse Tubules in Skeletal Muscle Fibers

Huntington’s disease (HD) is a fatal and progressive condition with severe debilitating motor defects and muscle weakness. Although classically recognized as a neurodegenerative disorder, there is increasing evidence of cell autonomous toxicity in skeletal muscle. We recently demonstrated that skeletal muscle fibers from the R6/2 model mouse of HD have a decrease in specific membrane capacitance, suggesting a loss of transverse tubule (t-tubule) membrane in R6/2 muscle. A previous report also indicated that Cav1.1 current was reduced in R6/2 skeletal muscle, suggesting defects in excitation–contraction (EC) coupling. Thus, we hypothesized that a loss and/or disruption of the skeletal muscle t-tubule system contributes to changes in EC coupling in R6/2 skeletal muscle. We used live-cell imaging with multiphoton confocal microscopy and transmission electron microscopy to assess the t-tubule architecture in late-stage R6/2 muscle and found no significant differences in the t-tubule system density, regularity, or integrity. However, electron microscopy images revealed that the cross-sectional area of t-tubules at the triad were 25% smaller in R6/2 compared with age-matched control skeletal muscle. Computer simulation revealed that the resulting decrease in the R6/2 t-tubule luminal conductance contributed to, but did not fully explain, the reduced R6/2 membrane capacitance. Analyses of bridging integrator-1 (Bin1), which plays a primary role in t-tubule formation, revealed decreased Bin1 protein levels and aberrant splicing of Bin1 mRNA in R6/2 muscle. Additionally, the distance between the t-tubule and sarcoplasmic reticulum was wider in R6/2 compared with control muscle, which was associated with a decrease in junctophilin 1 and 2 mRNA levels. Altogether, these findings can help explain dysregulated EC coupling and motor impairment in Huntington’s disease

Interface Train/ Infrastructure ferroviaire: influence de l'interface multi-contact et aptitude au shuntage du matériel roulant

La plupart des fonctions de signalisation nécessitent de connaître l'état d'occupation de portions de voie appelé « zones ». La détection d'une circulation sur une zone peut s'effectuer au moyen d'un « circuit de voie » équipant cette zone. Le circuit de voie est constitué d'un émetteur et d'un récepteur et d'une ligne de transmission formée par les rails. En l'absence de circulation sur la zone, le récepteur reçoit toute l'énergie de l'émetteur. En présence d'une circulation, les essieux du train « shuntent » le signal émis par l'émetteur induisant une très faible énergie reçue au niveau du récepteur. On dit qu'il y a « shuntage » du circuit de voie par la circulation et donc présence de la circulation sur la zone. La qualité du « shuntage » est donc primordiale dans la détection d'une circulation. Elle dépend de la bonne qualité du contact électrique « rail/roue ». L'évènement redouté que constitue le « déshuntage » conduit à signifier au système que la zone est libre de toute circulation alors qu'une circulation est présente sur la zone.   Le shuntage est une problématique système qui met en jeu les caractéristiques de l'infrastructure, des caractéristiques intrinsèques des circulations, de l'environnement et des conditions d'exploitations. Un problème demeure : le cadre physique du couplage électromécanique est mal établi. Les études s'intéressent à différents aspects du shuntage isolément du cadre du shuntage, il manque une étude qui permet d'unifier les contributions mécaniques et physiques : c'est le cadre mécanique du train circulant sur la voie qui conditionne le bon shuntage au travers du contact roue/rail. Il semble donc évident de devoir prendre en compte les caractéristiques physiques du train, du circuit de voie, et de l'exploitation, et les interactions entre celles-ci. Nous proposons une refondation des systèmes d'évaluation par « scores » utilisés par les belges et les néerlandais avec la possibilité de prendre en compte les paramètres aléatoires et imprédictibles intervenant dans le shuntage. Pour pouvoir faire cela, une étude statistique a été lancée sur des données de la SNCF. In fine, un système est proposé permettant l'admission d'un train sur les voies en le faisant correspondre à un point dans un espace abstrait dont les dimensions sont constituées de ses caractéristiques : l'admissibilité correspondra à la position de ce point dans cet espace abstrait par rapport à une norme fixée par les exploitants du réseau