Deconstructing Digital-to-Analog Converters with Inlet

Many statisticians would agree that, had it not been for DNS, the understanding of hierarchical databases might never have occurred. In fact, few systems engineers would disagree with the deployment of thin clients, demonstrates the structured importance of steganography. In or- der to address this riddle, we better understand how cache coherence [14] can be applied to the construction of RPCs

Examination of the seasonal variation in the abundance of Crangon shrimp and its relationship to the presence of the green sturgeon (Acipenser medirostris).pdf

A better understanding of the distribution and spawning behavior of Crangon shrimp and their relationship with their predators, including the green sturgeon, Acipenser medirostris, is an important step toward the larger goal to understand food webs of the nearshore continental shelf of the northeastern Pacific. Here, I examined how the biomass and energetics of two species of Crangon varied seasonally and by depth and the relationship between those patterns and the modeled distribution of A. medirostris, hypothesizing that the predicted presence of sturgeon would show a positive relationship with Crangon. With the help of Larkin Loewenherz, a colleague, I also examined the assemblage and spawning behavior of Crangon species across several habitat types in Yaquina Bay, Oregon, hypothesizing that C. franciscorum would dominate the bay while C. alaskensis would be most common offshore, and that these species would be of larger average mass offshore due to mature individuals moving down the salinity gradient. This latter investigation, dealing with spawning and assemblage, was presented to a public audience as the final project for the spring term 2014 BI 450 Marine Biology course at Hatfield Marine Science Center. Crangon samples were collected via beam trawl near Newport, Oregon, in 15 months over a span of 3 years (2010-2013). The presence of A. medirostris was predicted with help from Dr. David Huff, using a model based on data from coastal hydrophone arrays tracking acoustically tagged sturgeon, that included a number of physical covariates. For spawning and assemblage, samples were trawled from two stations in the river channel of Yaquina Bay and collected from two beach stations by seine net during spring 2014, and compared with offshore samples taken the previous year. Subsequent analyses found that for the most part, biomass density of Crangon was higher in fall and late summer than in winter or spring, driven by the more abundant C. alaskensis. Alternatively, Crangon stylirostris was most abundant in February and at shallower depths. Energetics of individual C. alaskensis was higher in winter than in fall and at shallower depths, and energetics of C. stylirostris showed no effect from month or depth. Biomass density of Crangon and calorimetry of C. alaskensis were both tested as explanatory variables for A. medirostris, but no relationship was found between these quantities and A. medirostris presence. For assemblage and spawning, we found that species assemblage differed between habitat types, but there was no significant difference in mean individual biomass between the channel and offshore habitats. We also found that there was no significant difference in average proportion of gravid C. alaskensis females between the channel and offshore habitats, leaving the question of where they go to spawn unanswered. We did find a positive correlation between the average total length and the percentage of gravid females. The observed patterns in Crangon abundance and energetics could be explained either by seasonal fluctuation of nutrients caused by upwelling, or by reproductive migration of individual shrimp once they reached sexual maturity. The lack of any correlation between Crangon distribution and A. medirostris presence doesn’t rule out some relationship between the two, but a larger spatial area of Crangon sampling might be required to detect those patterns if they exist. From our findings regarding assemblage and spawning, one of two possible interpretations exists: either salinity is not sufficiently different between the bay and the offshore area - or more likely, salinity is not a useful predictor of gravidity in Crangon. This study was important because it aimed to shed some light on the habits of an oft-overlooked group of animals, which likely play a significant role in coastal food webs. By sharing our work with an audience that extended beyond our immediate colleagues and included people outside of our field, our hope was that we would open the eyes of some of the public to just how many questions about the denizens of the supposedly familiar near-shore and estuarine environments still wait to be answered.Keywords: sturgeon, Biology, acipenser, medirostris, Shrimp, Marine, Gravidity, Population, Spawning, Gravid, Crangon, Hatfield, Estuary, Ecology, calorimetry, green, Pacific, Yaquina, Estuarine, Benthic, Caride

Investigation of Crangon species assemblage and spawning patterns in Yaquina Bay, OR.pdf

A better understanding of the distribution and spawning behavior of Crangon shrimp and their relationship with their predators, including the green sturgeon, Acipenser medirostris, is an important step toward the larger goal to understand food webs of the nearshore continental shelf of the northeastern Pacific. Here, I examined how the biomass and energetics of two species of Crangon varied seasonally and by depth and the relationship between those patterns and the modeled distribution of A. medirostris, hypothesizing that the predicted presence of sturgeon would show a positive relationship with Crangon. With the help of Larkin Loewenherz, a colleague, I also examined the assemblage and spawning behavior of Crangon species across several habitat types in Yaquina Bay, Oregon, hypothesizing that C. franciscorum would dominate the bay while C. alaskensis would be most common offshore, and that these species would be of larger average mass offshore due to mature individuals moving down the salinity gradient. This latter investigation, dealing with spawning and assemblage, was presented to a public audience as the final project for the spring term 2014 BI 450 Marine Biology course at Hatfield Marine Science Center. Crangon samples were collected via beam trawl near Newport, Oregon, in 15 months over a span of 3 years (2010-2013). The presence of A. medirostris was predicted with help from Dr. David Huff, using a model based on data from coastal hydrophone arrays tracking acoustically tagged sturgeon, that included a number of physical covariates. For spawning and assemblage, samples were trawled from two stations in the river channel of Yaquina Bay and collected from two beach stations by seine net during spring 2014, and compared with offshore samples taken the previous year. Subsequent analyses found that for the most part, biomass density of Crangon was higher in fall and late summer than in winter or spring, driven by the more abundant C. alaskensis. Alternatively, Crangon stylirostris was most abundant in February and at shallower depths. Energetics of individual C. alaskensis was higher in winter than in fall and at shallower depths, and energetics of C. stylirostris showed no effect from month or depth. Biomass density of Crangon and calorimetry of C. alaskensis were both tested as explanatory variables for A. medirostris, but no relationship was found between these quantities and A. medirostris presence. For assemblage and spawning, we found that species assemblage differed between habitat types, but there was no significant difference in mean individual biomass between the channel and offshore habitats. We also found that there was no significant difference in average proportion of gravid C. alaskensis females between the channel and offshore habitats, leaving the question of where they go to spawn unanswered. We did find a positive correlation between the average total length and the percentage of gravid females. The observed patterns in Crangon abundance and energetics could be explained either by seasonal fluctuation of nutrients caused by upwelling, or by reproductive migration of individual shrimp once they reached sexual maturity. The lack of any correlation between Crangon distribution and A. medirostris presence doesn’t rule out some relationship between the two, but a larger spatial area of Crangon sampling might be required to detect those patterns if they exist. From our findings regarding assemblage and spawning, one of two possible interpretations exists: either salinity is not sufficiently different between the bay and the offshore area - or more likely, salinity is not a useful predictor of gravidity in Crangon. This study was important because it aimed to shed some light on the habits of an oft-overlooked group of animals, which likely play a significant role in coastal food webs. By sharing our work with an audience that extended beyond our immediate colleagues and included people outside of our field, our hope was that we would open the eyes of some of the public to just how many questions about the denizens of the supposedly familiar near-shore and estuarine environments still wait to be answered.Keywords: Caridea, Gravidity, Hatfield, Estuary, Marine, Population, Biology, Ecology, green, Shrimp, Gravid, medirostris, calorimetry, acipenser, Spawning, Benthic, Crangon, sturgeon, Estuarine, Pacific, Yaquin

Sloan Digital Sky Survey III Photometric Quasar Clustering: Probing the Initial Conditions of the Universe using the Largest Volume

The Sloan Digital Sky Survey has surveyed 14,555 square degrees of the sky, and delivered over a trillion pixels of imaging data. We present the large-scale clustering of 1.6 million quasars between z = 0.5 and z = 2.5 that have been classified from this imaging, representing the highest density of quasars ever studied for clustering measurements. This data set spans ~11,000 square degrees and probes a volume of 80(Gpc/h)^3. In principle, such a large volume and medium density of tracers should facilitate high-precision cosmological constraints. We measure the angular clustering of photometrically classified quasars using an optimal quadratic estimator in four redshift slices with an accuracy of ~25% over a bin width of l ~10 - 15 on scales corresponding to matter-radiation equality and larger (l ~ 2 - 30). Observational systematics can strongly bias clustering measurements on large scales, which can mimic cosmologically relevant signals such as deviations from Gaussianity in the spectrum of primordial perturbations. We account for systematics by employing a new method recently proposed by Agarwal et al. (2014) to the clustering of photometrically classified quasars. We carefully apply our methodology to mitigate known observational systematics and further remove angular bins that are contaminated by unknown systematics. Combining quasar data with the photometric luminous red galaxy (LRG) sample of Ross et al. (2011) and Ho et al. (2012), and marginalizing over all bias and shot noise-like parameters, we obtain a constraint on local primordial non-Gaussianity of fNL = -113+/-154 (1\sigma error). [Abridged]Comment: 35 pages, 15 figure

Climate vulnerability assessment for Pacific salmon and steelhead in the California Current Large Marine Ecosystem.

Major ecological realignments are already occurring in response to climate change. To be successful, conservation strategies now need to account for geographical patterns in traits sensitive to climate change, as well as climate threats to species-level diversity. As part of an effort to provide such information, we conducted a climate vulnerability assessment that included all anadromous Pacific salmon and steelhead (Oncorhynchus spp.) population units listed under the U.S. Endangered Species Act. Using an expert-based scoring system, we ranked 20 attributes for the 28 listed units and 5 additional units. Attributes captured biological sensitivity, or the strength of linkages between each listing unit and the present climate; climate exposure, or the magnitude of projected change in local environmental conditions; and adaptive capacity, or the ability to modify phenotypes to cope with new climatic conditions. Each listing unit was then assigned one of four vulnerability categories. Units ranked most vulnerable overall were Chinook (O. tshawytscha) in the California Central Valley, coho (O. kisutch) in California and southern Oregon, sockeye (O. nerka) in the Snake River Basin, and spring-run Chinook in the interior Columbia and Willamette River Basins. We identified units with similar vulnerability profiles using a hierarchical cluster analysis. Life history characteristics, especially freshwater and estuary residence times, interplayed with gradations in exposure from south to north and from coastal to interior regions to generate landscape-level patterns within each species. Nearly all listing units faced high exposures to projected increases in stream temperature, sea surface temperature, and ocean acidification, but other aspects of exposure peaked in particular regions. Anthropogenic factors, especially migration barriers, habitat degradation, and hatchery influence, have reduced the adaptive capacity of most steelhead and salmon populations. Enhancing adaptive capacity is essential to mitigate for the increasing threat of climate change. Collectively, these results provide a framework to support recovery planning that considers climate impacts on the majority of West Coast anadromous salmonids

Early Ocean Distribution of Juvenile Chinook Salmon in an Upwelling Ecosystem

Extreme variability in abundance of California salmon populations is often ascribed to ocean conditions, yet relatively little is known about their marine life-history. To investigate which ocean conditions influence their distribution and abundance, we surveyed juvenile Chinook salmon (Oncorhynchus tshawytscha) within the California Current (central California (37o 30’ N) to Newport, Oregon (44o 00’ N)) for a two-week period over three summers (2010-2012). At each station, we measured chlorophyll a as an indicator of primary productivity, acoustic-based metrics of zooplankton density as an indicator of potential prey availability, and physical characteristics such as bottom depth, temperature, and salinity. We also measured fork lengths and collected genetic samples from each salmon that was caught. Genetic stock identification revealed that the majority of juvenile salmon were from the Central Valley and the Klamath Basin (91-98%). We constructed generalized logistic-linear negative binomial hurdle models and chose the best model(s) using AIC to determine which covariates influenced salmon presence and, at locations where salmon were present, determined the variables that influenced their abundance. The probability of salmon presence was highest in shallower waters with high chlorophyll a concentration and close to an individual’s natal river. Catch abundance was primarily influenced by year, mean fork length, and proximity to natal rivers. At the scale of sampling stations, presence and abundance was not related to acoustic indices of zooplankton density. In the weeks to months following ocean entry, California’s juvenile Chinook salmon population appears to be primarily constrained to coastal waters near natal river outlets

Past and estimated future impact of invasive alien mammals on insular threatened vertebrate populations

Invasive mammals on islands pose severe, ongoing threats to global biodiversity. However, the severity of threats from different mammals, and the role of interacting biotic and abiotic factors in driving extinctions, remain poorly understood at a global scale. Here we model global extirpation patterns for island populations of threatened and extinct vertebrates. Extirpations are driven by interacting factors including invasive rats, cats, pigs, mustelids and mongooses, native species taxonomic class and volancy, island size, precipitation and human presence. We show that controlling or eradicating the relevant invasive mammals could prevent 41–75% of predicted future extirpations. The magnitude of benefits varies across species and environments; for example, managing invasive mammals on small, dry islands could halve the extirpation risk for highly threatened birds and mammals, while doing so on large, wet islands may have little benefit. Our results provide quantitative estimates of conservation benefits and, when combined with costs in a return-on-investment framework, can guide efficient conservation strategies

GREAT3 results I: systematic errors in shear estimation and the impact of real galaxy morphology

We present first results from the third GRavitational lEnsing Accuracy Testing (GREAT3) challenge, the third in a sequence of challenges for testing methods of inferring weak gravitational lensing shear distortions from simulated galaxy images. GREAT3 was divided into experiments to test three specific questions, and included simulated space- and ground-based data with constant or cosmologically-varying shear fields. The simplest (control) experiment included parametric galaxies with a realistic distribution of signal-to-noise, size, and ellipticity, and a complex point spread function (PSF). The other experiments tested the additional impact of realistic galaxy morphology, multiple exposure imaging, and the uncertainty about a spatially-varying PSF; the last two questions will be explored in Paper II. The 24 participating teams competed to estimate lensing shears to within systematic error tolerances for upcoming Stage-IV dark energy surveys, making 1525 submissions overall. GREAT3 saw considerable variety and innovation in the types of methods applied. Several teams now meet or exceed the targets in many of the tests conducted (to within the statistical errors). We conclude that the presence of realistic galaxy morphology in simulations changes shear calibration biases by $\sim 1$ per cent for a wide range of methods. Other effects such as truncation biases due to finite galaxy postage stamps, and the impact of galaxy type as measured by the S\'{e}rsic index, are quantified for the first time. Our results generalize previous studies regarding sensitivities to galaxy size and signal-to-noise, and to PSF properties such as seeing and defocus. Almost all methods' results support the simple model in which additive shear biases depend linearly on PSF ellipticity.Comment: 32 pages + 15 pages of technical appendices; 28 figures; submitted to MNRAS; latest version has minor updates in presentation of 4 figures, no changes in content or conclusion