Enhancing AIS to Improve Whale-Ship Collision Avoidance and Maritime Security

Whale-ship strikes are of growing worldwide concern due to the steady growth of commercial shipping. Improving the current situation involves the creation of a communication capability allowing whale position information to be estimated and exchanged among vessels and other observation assets. An early example of such a system has been implemented for the shipping lane approaches to the harbor of Boston, Massachusetts where ship traffic transits areas of the Stellwagen Bank National Marine Sanctuary frequently used by whales. It uses the Automated Identification Systems (AIS) technology, currently required for larger vessels but becoming more common in all classes of vessels. However, we believe the default mode of AIS operation will be inadequate to meet the long-term needs of whale-ship collision avoidance, and will likewise fall short of meeting other current and future marine safety and security communication needs. This paper explores the emerging safety and security needs for vessel communications, and considers the consequences of a communication framework supporting asynchronous messaging that can be used to enhance the basic AIS capability. The options we analyze can be pursued within the AIS standardization process, or independently developed with attention to compatibility with existing AIS systems. Examples are discussed for minimizing ship interactions with Humpback Whales and endangered North Atlantic Right Whales on the east coast, and North Pacific Right Whales, Bowhead Whales, Humpback Whales, Blue Whales and Beluga Whales in west coast, Alaskan and Hawaiian waters

The Luminosity, Mass, and Age Distributions of Compact Star Clusters in M83 Based on HST/WFC3 Observations

The newly installed Wide Field Camera 3 (WFC3) on the Hubble Space Telescope has been used to obtain multi-band images of the nearby spiral galaxy M83. These new observations are the deepest and highest resolution images ever taken of a grand-design spiral, particularly in the near ultraviolet, and allow us to better differentiate compact star clusters from individual stars and to measure the luminosities of even faint clusters in the U band. We find that the luminosity function for clusters outside of the very crowded starburst nucleus can be approximated by a power law, dN/dL \propto L^{alpha}, with alpha = -2.04 +/- 0.08, down to M_V ~ -5.5. We test the sensitivity of the luminosity function to different selection techniques, filters, binning, and aperture correction determinations, and find that none of these contribute significantly to uncertainties in alpha. We estimate ages and masses for the clusters by comparing their measured UBVI,Halpha colors with predictions from single stellar population models. The age distribution of the clusters can be approximated by a power-law, dN/dt propto t^{gamma}, with gamma=-0.9 +/- 0.2, for M > few x 10^3 Msun and t < 4x10^8 yr. This indicates that clusters are disrupted quickly, with ~80-90% disrupted each decade in age over this time. The mass function of clusters over the same M-t range is a power law, dN/dM propto M^{beta}, with beta=-1.94 +/- 0.16, and does not have bends or show curvature at either high or low masses. Therefore, we do not find evidence for a physical upper mass limit, M_C, or for the earlier disruption of lower mass clusters when compared with higher mass clusters, i.e. mass-dependent disruption. We briefly discuss these implications for the formation and disruption of the clusters.Comment: 36 pages, 13 figures, 1 table; accepted for publication in the Astrophysical Journa

Resting State Functional Connectivity of the Supplementary Motor Area and the Caudate Nucleus in Prodromal Huntington\u27s Disease

Huntington’s disease (HD) is a fatal neurodegenerative genetic disease that causes motor difficulties, mood impairment, and cognitive dysfunction. Prodromal Huntington’s disease (PrHD) refers to people who carry the mutated huntingtin (htt) gene, but do not yet fit the criteria needed for a full diagnosis. Changes in mood typically begin in the prodromal phase, and apathy is a particularly devastating change that progresses in severity throughout the course of the disease. We investigated neural connectivity changes that could be associated with apathy severity within this population. We performed a seed-based connectivity analysis on resting state scans of 89 (PrHD) patients, with the supplementary motor area, bilateral caudate and caudate head as our regions of interest. We found that apathy severity was significantly correlated with increased connectivity between the caudate head and the supplementary motor area (p = 0.03). Further analyses are needed to establish the extent of the effect of caudate atrophy on this relationship, which we would predict would be highly related due to the degenerative nature of the disease

Relationships among Fine Sediment Settling and Suspension, Bed Erodibility, and Particle Type in the York River Estuary, Virginia

In order to understand the processes controlling the temporal variability in settling velocity (Ws) and bed erodibility (ε), in the middle reaches of the York River estuary, VA, the relationships between the hydrodynamics and particle types were investigated with a near-­‐bed Acoustic Doppler Velocimeter (ADV) and the York River 3-­‐D Hydrodynamic Cohesive Bed Model. ADV observations of the flow characteristics that occurred over a strong temporal transition period indicated that Ws and ε were characterized by two distinct regimes with contrasting sediment and water column characteristics: (i) a physically-­‐dominated regime (Regime 1) which was a period dominated by flocculated muds (flocs), and (ii) a biologically-­‐influenced regime (Regime 2) which was a period dominated by biologically formed pellets mixed with flocs. During Regime 1, Ws averaged about 0.5 mm/s, and ε averaged about 3 kg/m2/Pa. In contrast, during Regime 2 average Ws increased to 1.5 mm/s, and average ε dropped to 1 kg/m2/Pa. The change between these two regimes and the transition in Ws and ε were linked with the arrival and departure of a seasonal density front. Comparison between ADV observations and the results from the York River 3-­‐D Hydrodynamic Cohesive Bed Model suggested that the current model version was not conducive to examining the temporal variability in settling velocity associated with the transition of the distinct sediment regimes. The existing model version estimated realistic values for current speed and concentration and resolved the daily variation associated with in current speed, bed stress, concentration, and settling velocity. However, model estimates of bed stress, current speed, settling velocity, and erodibility did not suggest the presence of two distinct sediment regimes. The model did a poor job of predicting peak bed stresses and settling velocities. Both were over estimated by a factor of 2 throughout most of the study period. Possible modifications to create a version that is able to simulate the bed stresses and sediment properties (i.e. erodibility and settling velocity) during each regime with more accuracy are: (1) define finer sediment classes in the model that are more representative of the water column and not just the seabed, (2) use a consolidation time scale of 5 days rather than 24 hours to allow more sediment to be suspended at lower bed stresses, (3) further reduce hydraulic roughness, and (4) turn on sediment induced stratification

Regional Patterns of Fish and Wildlife Harvests in Contemporary Alaska

Subsistence harvests of fish and wildlife play a vital role in the economies and ways of life of rural Alaska communities. State and federal laws establish a priority for subsistence over other fishing and hunting. These laws recognize that the economic, cultural, and social role of subsistence fishing and hunting is not uniform across Alaska: federal law limits eligibility to rural residents, and state law, while allowing all state residents to participate, requires the identification of nonsubsistence areas where subsistence fishing and hunting are not permitted. But defining “rural Alaska” and “nonsubsistence areas” sparked decades of political debate and litigation. A review of nonsubsistence areas by the Alaska Joint Board of Fisheries and Game in 2013 resulted in updated estimates of noncommercial fish and wildlife harvests. Comprehensive data from systematic household surveys in 198 rural communities provided a basis for estimating harvest levels and trends at census-area and statewide levels and crucial input to board deliberations. In 2012, rural Alaska harvests averaged 134 kg/person, while urban Alaska harvests averaged 10 kg/person. The statewide rural harvest was 26% below an estimate for the 1980s, but changes varied by region. Throughout the Arctic and Subarctic, factors shaping subsistence harvests include development, the rising costs of living, shifting resource populations, regulations, climate change, and cultural change. Understanding the vulnerability and adaptability of northern communities requires monitoring of subsistence harvests through annual programs and periodic comprehensive community studies.La récolte du poisson et du gibier à des fins de subsistance joue un rôle essentiel dans les économies et les modes de vie des collectivités rurales de l’Alaska. La législation de l’État et la législation fédérale accordent la priorité à la récolte de subsistance par opposition à toute autre forme de chasse ou de pêche. Ces lois reconnaissent que le rôle économique, culturel et social de la pêche et de la chasse de subsistance n’est pas uniforme à l’échelle de l’Alaska : la législation fédérale restreint l’admissibilité aux résidents des milieux ruraux, tandis que la législation de l’État, bien qu’elle permette à tous les résidents de l’État de participer à ces activités, exige l’identification des zones de non-subsistance où la chasse et la pêche de subsistance sont interdites. Cependant, la définition de ce qui constitue l’« Alaska rural » et les « zones de non-subsistance » a fait l’objet d’un débat politique et d’un litige pendant des dizaines d’années. L’examen des zones de non-subsistance réalisé par l’Alaska Joint Board of Fisheries and Game (le conseil) en 2013 a donné lieu à l’estimation actualisée des récoltes non commerciales du poisson et du gibier. Des données exhaustives prélevées grâce à des sondages systématiques effectués auprès des ménages de 198 collectivités rurales ont servi de fondement à l’estimation des récoltes et à la détermination des tendances dans la zone de recensement de même que des niveaux à l’échelle de l’État, en plus de présenter des données cruciales ayant servi dans le cadre des délibérations du conseil. En 2012, les récoltes des régions rurales de l’Alaska ont atteint 134 kg/personne en moyenne, tandis que les récoltes des régions urbaines de l’Alaska ont atteint 10 kg/personne en moyenne. À l’échelle de l’État, la récolte rurale a été inférieure à l’estimation faite pour les années 1980 dans une mesure de 26 %, mais les changements variaient d’une région à l’autre. Dans l’Arctique et dans la zone subarctique, les facteurs exerçant une influence sur les récoltes de subsistance comprennent le développement, le coût de la vie à la hausse, l’évolution des populations de ressources, la réglementation, le changement climatique et le changement culturel. Pour comprendre la vulnérabilité et l’adaptabilité des collectivités du Nord, il y a lieu de surveiller les récoltes de subsistance par le biais de programmes annuels et d’études communautaires périodiques et exhaustives

Macroscopic Discontinuous Shear Thickening vs Local Shear Jamming in Cornstarch

We study the emergence of discontinuous shear-thickening (DST) in cornstarch, by combining macroscopic rheometry with local Magnetic Resonance Imaging (MRI) measurements. We bring evidence that macroscopic DST is observed only when the flow separates into a low-density flowing and a high-density jammed region. In the shear-thickened steady state, the local rheology in the flowing region, is not DST but, strikingly, is often shear-thinning. Our data thus show that the stress jump measured during DST, in cornstach, does not capture a secondary, high-viscosity branch of the local steady rheology, but results from the existence of a shear jamming limit at volume fractions quite significantly below random close packing.Comment: To be published in PR

Acquisition of acid vapor and aerosol concentration data for use in dry deposition studies in the South Coast Air Basin

An atmospheric monitoring network was operated throughout the South Coast Air Basin in the greater Los Angeles area during the year 1986. The primary objective of this study was to measure the spatial and temporal concentration distributions of atmospheric gas phase and particulate phase acids and bases in support of the California Air Resources Board's dry deposition research program. Gaseous pollutants measured include HNO_3, HCl, HF, HBr, formic acid, acetic acid and ammonia. The chemical composition of the airborne particulate matter complex was examined in three size ranges: fine particles (less than 2.2 μm aerodynamic diameter, AD), PM_(10) (less than 10 μm AD) and total particles (no size discrimination). Upwind of the air basin at San Nicolas Island, gas phase acids concentrations are very low: averaging 0.3 μg m^(-3) (0.1 ppb) for HNO_3, 0.8 μg m^(-3) for HCl, 0.13 μg m^(-3) for HF, and 2.6 μg m^(-3) for formic acid. Annual average HN03 concentrations ranged from 3.1 μg m^(-3) (1.2 ppb) near the Southern California coast to 6.9 μg m^(-3) (2.7 ppb) at an inland site in the San Gabriel Mountains. HCl concentrations within the South Coast Air Basin averaged from 0.8 μg m^(-3) to 1.8 μg m^(-3) during the year 1986. Long-term average HF concentrations within the air basin are very low, in the range from 0.14 to 0.22 μg m^(-3) between monitoring sites. Long-term average formic acid concentrations are lowest near the coastline (5.0 μg m^(-3) at Hawthorne), with the highest average concentrations (10.7 μg m^(-3)) observed inland at Upland. Ammonia concentrations at low elevation within the South Coast Air Basin average from 2.1 μg m^(-3) to 4.4 μg m^(-3) at all sites except Rubidoux. Rubidoux is located directly downwind of a large ammonia source created by dairy farming and other agricultural activities in the Chino area. Ammonia concentrations at Rubidoux average 30 μg m^(-3) during 1986, a factor of approximately 10 higher than elsewhere in the air basin. Annual average PM_(10) mass concentrations within the South Coast Air Basin ranged from 47.0 μg m^(-3) along the coast to 87.4 μg m^(-3) at Rubidoux, the farthest inland monitoring site. Five major aerosol components (carbonaceous material, NO_3^-, SO_4^-, NH_4^+ and soil-related material) accounted for greater than 80% of the annual average PM_(10) mass concentration at all on-land monitoring stations. A peak 24-h average PM_(10) mass concentration of 299 μg m^(-3) was observed at Rubidoux during 1986. That value is a factor of 2 higher than the federal 24-h average PM_(10) concentration standard, and a factor of 6 higher than the State of California PM_(10) standard. More than 40% of the PM_(10) aerosol mass measured at Rubidoux during that peak day event consisted of aerosol nitrates plus ammonium ion. Reaction of gaseous nitric acid to form aerosol nitrates was a major contributor to the high PM_(10) concentrations observed in the Rubidoux area near Riverside, California