Quantifying marine vessel traffic from aerial surveys in the Salish Sea

There are a number of potential impacts associated with vessel traffic on marine ecosystems, including noise and oil pollution, ship-strikes, and fishing and fisheries bycatch. To assess these impacts, many studies employ marine traffic data collected using Automatic Identification Systems (AIS) onboard vessels. However, AIS only captures a fraction of the actual marine traffic because it omits many of the smaller vessels, which are not legally required to carry AIS. Without this information, the assessment of vessel-associated impacts based on AIS is inherently flawed, and underestimated. The NEMES (Noise Exposure to the Marine Environment from Ships) project is particularly interested in this unknown component of marine traffic as non-AIS vessels are likely contributing a considerable amount of noise in the Salish Sea. With the assistance of the National Aerial Surveillance Program (NASP), we have been collecting vessel traffic information for both AIS and non-AIS vessels during two years (2016, 2017) in parts of the Salish Sea. The AIS receiver and sensors onboard the NASP aircraft can collect AIS information and video with positional information of target objects such as vessels. The video also allows the characterization of the vessel type (e.g., sailboat, motorboat, fishing vessel) and vessel activity (i.e., fishing, motoring or sailing). Results indicate that non-AIS vessels contribute at least 60% of the overall vessel traffic in surveyed areas between 2016 and 2017. The majority of these non-AIS vessels are recreational vessels, particularly during the summer months and near popular touristic destinations such as the Southern Gulf Islands. Through this work, we are now able to build a more complete picture of the distribution and type of vessels using the Salish Sea, and have a better understanding of their potential impacts to the marine ecosystem

Layer Features of the Lattice Gas Model for Self-Organized Criticality

A layer-by-layer description of the asymmetric lattice gas model for 1/f-noise suggested by Jensen [Phys. Rev. Lett. 64, 3103 (1990)] is presented. The power spectra of the lattice layers in the direction perpendicular to the particle flux is studied in order to understand how the white noise at the input boundary evolves, on the average, into 1/f-noise for the system. The effects of high boundary drive and uniform driving force on the power spectrum of the total number of diffusing particles are considered. In the case of nearest-neighbor particle interactions, high statistics simulation results show that the power spectra of single lattice layers are characterized by different $\beta_x$ exponents such that $\beta_x \to 1.9$ as one approaches the outer boundary.Comment: LaTeX, figures upon reques

Gel transitions in colloidal suspensions

The idealized mode coupling theory (MCT) is applied to colloidal systems interacting via short-range attractive interactions of Yukawa form. At low temperatures MCT predicts a slowing down of the local dynamics and ergodicity breaking transitions. The nonergodicity transitions share many features with the colloidal gel transition, and are proposed to be the source of gelation in colloidal systems. Previous calculations of the phase diagram are complemented with additional data for shorter ranges of the attractive interaction, showing that the path of the nonergodicity transition line is then unimpeded by the gas-liquid critical curve at low temperatures. Particular attention is given to the critical nonergodicity parameters, motivated by recent experimental measurements. An asymptotic model is developed, valid for dilute systems of spheres interacting via strong short-range attractions, and is shown to capture all aspects of the low temperature MCT nonergodicity transitions.Comment: 12 pages, LaTeX, 5 eps figures, uses ioplppt.sty, to appear in J. Phys.: Condens. Matte

Acute sodium overload produces renal tubulointerstitial inflammation in normal rats

The aim of the present study was to determine whether acute sodium overload could trigger an inflammatory reaction in the tubulointerstitial (TI) compartment in normal rats. Four groups of Sprague-Dawley rats received increasing NaCl concentrations by intravenous infusion. Control (C): Na + 0.15M; G1: Na+ 0.5M; G2: Na+ 1.0M; and G3: Na+ 1.5M. Creatinine clearance, mean arterial pressure (MAP), renal blood flow (RBF), and sodium fractional excretion were determined. Transforming growth factor β1 (TGF-β1), α-smooth muscle actin (α-SMA), RANTES, transcription factor nuclear factor-kappa B (NF-κB), and angiotensin II (ANG II) were evaluated in kidneys by immunohistochemistry. Animals with NaCl overload showed normal glomerular function without MAP and RBF modifications and exhibited a concentration-dependent natriuretic response. Plasmatic sodium increased in G2 (P G2>C group. These results suggest that an acute sodium overload is able 'per se' to initiate TI endothelial inflammatory reaction (glomerular and peritubular) and incipient fibrosis in normal rats, independently of hemodynamic modifications. Furthermore, these findings are consistent with the possibility that activation of NF-κB and local ANG II may be involved in the pathway of this inflammatory process.Fil: Roson, Maria Ines. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cavallero, Carmen Susana. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Della Penna, Silvana. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Cao, Gabriel Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Hospital Alemán; ArgentinaFil: Gorzalczany, Susana Beatriz. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Pandolfo, Marcela. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Kuprewicz, A.. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Canessa, O.. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Toblli, Jorge Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Hospital Alemán; ArgentinaFil: Fernandez, Belisario Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentin

Capturing Information on Vessels and Cetaceans: developing a passive monitoring system for Boundary Pass

As marine traffic intensifies in the Salish Sea, cetaceans, and in particular, Southern Resident Killer Whales (SRKWs), are continually facing increasing amounts of exposure to noise and other disturbances from movements of vessels. While the majority of large vessel activity can be captured and assessed through the use of Automatic Identification Systems (AIS), the contribution of smaller non-AIS vessels is difficult to quantify and currently largely under assessed. Increasingly, government and industry are required to take operational and strategic mitigation measures to minimise vessel disturbances on cetaceans without reliable, comprehensive data and analysis to inform those decisions. Therefore this work focuses on filling these gaps by collecting information on both non-AIS vessels and the presence of marine mammal (including SRKW) within Boundary Pass) using three passive forms of data collection: an AIS receiver, hydrophones and a land-based camera. This talk describes an outline of the camera work being undertaken, from the design stages to installation. It will highlight some of the initial findings from the early analysis work along with some of the challenges and limitations of this type of data. Additionally, acoustic data on cetaceans in Boundary Pass will also be presented. Unlike the camera this form of passive monitoring is only able to capture the presence of cetaceans when they are vocalizing. Evidence already exists to suggest that some species reduce their rate of vocalization in the presence of vessels (and their associated noise). Therefore, integration of both acoustic and visual data will enable us to build a more complete picture of cetacean habitat use and the relationship between vessels and cetaceans in Boundary Pass. Furthermore, the information obtained through analysis of this data is also particularly important for informing models that aim to assess the level of vessel disturbance cetaceans are subjected to

Effective Interactions and Volume Energies in Charged Colloids: Linear Response Theory

Interparticle interactions in charge-stabilized colloidal suspensions, of arbitrary salt concentration, are described at the level of effective interactions in an equivalent one-component system. Integrating out from the partition function the degrees of freedom of all microions, and assuming linear response to the macroion charges, general expressions are obtained for both an effective electrostatic pair interaction and an associated microion volume energy. For macroions with hard-sphere cores, the effective interaction is of the DLVO screened-Coulomb form, but with a modified screening constant that incorporates excluded volume effects. The volume energy -- a natural consequence of the one-component reduction -- contributes to the total free energy and can significantly influence thermodynamic properties in the limit of low-salt concentration. As illustrations, the osmotic pressure and bulk modulus are computed and compared with recent experimental measurements for deionized suspensions. For macroions of sufficient charge and concentration, it is shown that the counterions can act to soften or destabilize colloidal crystals.Comment: 14 pages, including 3 figure

Modulation of epithelial sodium channel (ENaC) expression in mouse lung infected with Pseudomonas aeruginosa

BACKGROUND: The intratracheal instillation of Pseudomonas aeruginosa entrapped in agar beads in the mouse lung leads to chronic lung infection in susceptible mouse strains. As the infection generates a strong inflammatory response with some lung edema, we tested if it could modulate the expression of genes involved in lung liquid clearance, such as the α, β and γ subunits of the epithelial sodium channel (ENaC) and the catalytic subunit of Na(+)-K(+)-ATPase. METHODS: Pseudomonas aeruginosa entrapped in agar beads were instilled in the lung of resistant (BalB/c) and susceptible (DBA/2, C57BL/6 and A/J) mouse strains. The mRNA expression of ENaC and Na(+)-K(+)-ATPase subunits was tested in the lung by Northern blot following a 3 hours to 14 days infection. RESULTS: The infection of the different mouse strains evoked regulation of α and β ENaC mRNA. Following Pseudomonas instillation, the expression of αENaC mRNA decreased to a median of 43% on days 3 and 7 after infection and was still decreased to a median of 45% 14 days after infection (p < 0.05). The relative expression of βENaC mRNA was transiently increased to a median of 241%, 24 h post-infection before decreasing to a median of 43% and 54% of control on days 3 and 7 post-infection (p < 0.05). No significant modulation of γENaC mRNA was detected although the general pattern of expression of the subunit was similar to α and β subunits. No modulation of α(1)Na(+)-K(+)-ATPase mRNA, the catalytic subunit of the sodium pump, was recorded. The distinctive expression profiles of the three subunits were not different, between the susceptible and resistant mouse strains. CONCLUSIONS: These results show that Pseudomonas infection, by modulating ENaC subunit expression, could influence edema formation and clearance in infected lungs

Inherent Dynamics of the Acid-Sensing Ion Channel 1 Correlates with the Gating Mechanism

A combination of computational and experimental approaches reveals the dynamics of ASIC1 gating, involving a deformation of the channel that triggers “twist-to-open” motions of the channel pore