The ecology of the Arctic char and the dolly varden in the Becharof Lake drainage, Alaska

Thesis (M.S.) University of Alaska Fairbanks, 2000Becharof Lake is home to both Arctic char (Salvelinus alpinus) and the closely related Dolly Varden (Salvelinus malma), two species known not only to be similar in appearance but also to exhibit similar life histories. The body morphometry, otolith microchemistry, and stomach contents of both species were studied in fish collected from May to September 1998. Morphometric and meristic analysis revealed clear separation in body structure between the two species, as well as potential sub-populations within each species. Otolith microchemistry revealed incidences of anadromy and non-anadromy in both species. Stomach content analysis revealed a broad feeding niche but smaller ranges in food types in individual Arctic char with little seasonal preference, whereas Dolly Varden showed seasonality in food choices. Data suggest that both species can move in and out of the lake system, and that little competition for food or habitat occurs between the two species in the summer months

Utility of Pop-Up Satellite Archival Tags to Study the Summer Dispersal and Habitat Occupancy of Dolly Varden in Arctic Alaska

In Arctic Alaska, Dolly Varden Salvelinus malma is highly valued as a subsistence fish; however, little is known about its marine ecology. New advances in electronic tagging, such as pop-up satellite archival tags (PSATs), provide scientists with a fishery-independent means of studying several aspects of this species’ movement and ecology. To evaluate the usefulness of this technology, we attached 52 PSATs to Dolly Varden in the Wulik River, which flows from northwestern Alaska into the Chukchi Sea, to study several characteristics of the marine habits of this species. Overall, PSATs provided unprecedented information about summer dispersal of Dolly Varden, including the first evidence of offshore dispersal in the Chukchi Sea, as well as previously documented dispersal types such as movement to other rivers and southerly nearshore movements in northwestern Alaska. On the basis of minimal observable evidence of tag-induced behavioral effects, as well as movements of more than 450 km by fish at liberty (i.e., between tag deployment and release or recapture), we conclude that PSATs offer an effective alternative method for studying several aspects of Dolly Varden dispersal and ecology in areas where it is not practical or feasible to capture these fish, such as coastal and offshore regions of Arctic AlaskaDans l’Alaska de l’Arctique, l’omble du Pacifique, Salvelinus malma revêt une grande importance en tant que poisson de subsistance. Toutefois, on en sait peu sur son écologie marine. Les progrès réalisés en matière de traçabilité électronique, notamment en ce qui a trait aux étiquettes de collecte de données par satellite (PSAT) permettent aux scientifiques d’étudier plusieurs aspects des déplacements et de l’écologie de cette espèce sans dépendre de la pêche. Afin d’évaluer l’utilité de cette technologie, nous avons fixé 52 PSAT à des ombles du Pacifique de la rivière Wulik, qui s’écoule depuis le nord-ouest de l’Alaska jusqu’à la mer des Tchouktches, pour étudier plusieurs caractéristiques des habitudes aquatiques de cette espèce. Dans l’ensemble, les PSAT ont permis de recueillir des renseignements sans précédent au sujet de la dispersion estivale de l’omble du Pacifique, y compris la première preuve de dispersion extracôtière dans la mer des Tchouktches et d’autres types de dispersion anciennement documentés, comme les déplacements vers d’autres cours d’eau et les déplacements sublittoraux en direction sud, dans le nord-ouest de l’Alaska. D’après un minimum d’éléments de preuve observables quant aux effets découlant de la présence d’étiquettes sur le comportement ainsi que d’après les déplacements de plus de 450 kilomètres des poissons en liberté (c’est-à-dire entre l’installation des étiquettes et le relâchement ou la recapture), nous concluons que les PSAT présentent une méthode de rechange efficace pour étudier plusieurs aspects de la dispersion et de l’écologie de l’omble du Pacifique dans des endroits où il n’est pas pratique ou réalisable de prendre ces poissons, comme dans les régions côtières et extracôtières de l’Alaska de l’Arctique

A 915 MHz wristwatch-integrated antenna for wireless health monitoring

A compact 915 MHz antenna integrated within a wristwatch wireless sensor device is presented. The antenna is a variant of a planar inverted-F antenna (PIFA) and uses a dual-resonator configuration. The results of simulation and measurement are shown to be in good agreement with the antenna exhibiting desirable impedance and radiation characteristics together with low Specific Absorption Rate (SAR) performance. The antenna is fabricated using a low cost flexible printed circuit and is fully integrated into the watch device. Measurements on the prototype antenna show a -10 dB impedance bandwidth of 30 MHz, a peak realized gain of -4.9 dBi and a peak radiation efficiency of 15.9% at 915 MHz. The antenna also has a low SAR value of 0.003 W/kg making it suitable for a wide range of wrist-worn wireless applications

ATLAS Run 1 searches for direct pair production of third-generation squarks at the Large Hadron Collider

This paper reviews and extends searches for the direct pair production of the scalar supersymmetric partners of the top and bottom quarks in proton-proton collisions collected by the ATLAS collaboration during the LHC Run 1. Most of the analyses use 20 fb$^{-1}$ of collisions at a centre-of-mass energy of $\sqrt{s}$ = 8 TeV, although in some case an additional 4.7 fb$^{-1}$ of collision data at $\sqrt{s}$ = 7 TeV are used. New analyses are introduced to improve the sensitivity to specific regions of the model parameter space. Since no evidence of third-generation squarks is found, exclusion limits are derived by combining several analyses and are presented in both a simplified model framework, assuming simple decay chains, as well as within the context of more elaborate phenomenological supersymmetric models

Utility of Pop-Up Satellite Archival Tags to Study the Summer Dispersal and Habitat Occupancy of Dolly Varden in Arctic Alaska

In Arctic Alaska, Dolly Varden Salvelinus malma is highly valued as a subsistence fish; however, little is known about its marine ecology. New advances in electronic tagging, such as pop-up satellite archival tags (PSATs), provide scientists with a fishery-independent means of studying several aspects of this species’ movement and ecology. To evaluate the usefulness of this technology, we attached 52 PSATs to Dolly Varden in the Wulik River, which flows from northwestern Alaska into the Chukchi Sea, to study several characteristics of the marine habits of this species. Overall, PSATs provided unprecedented information about summer dispersal of Dolly Varden, including the first evidence of offshore dispersal in the Chukchi Sea, as well as previously documented dispersal types such as movement to other rivers and southerly nearshore movements in northwestern Alaska. On the basis of minimal observable evidence of tag-induced behavioral effects, as well as movements of more than 450 km by fish at liberty (i.e., between tag deployment and release or recapture), we conclude that PSATs offer an effective alternative method for studying several aspects of Dolly Varden dispersal and ecology in areas where it is not practical or feasible to capture these fish, such as coastal and offshore regions of Arctic Alaska</jats:p