8,875 research outputs found
Regulating the Arctic Gold Rush: Recommended Regulatory Reforms to Protect Alaska’s Arctic Environment From Offshore Oil Drilling Pollution
Since 2008, major oil and gas operators have invested billions attempting to drill Arctic Alaska\u27s Outer Continental Shelf. However, offshore drilling in the extreme Arctic is fraught with infrastructural, technological and environmental challenges that could result in enormous damages if an accident ever occurred. While offshore drilling operations would significantly benefit both the state of Alaska and the United States, it is imperative that the United States\u27 offshore regulatory regime adequately protects the Arctic Alaskan environment and innocent third parties. This Note examines the shortcomings of the United States\u27 current offshore drilling regulatory regime and proposes a four-part scheme that properly incentivizes operators to drill safely and adequately compensates damaged parties. The United States should revise its regulatory regime by: (1) significantly increasing the liability cap; (2) increasing an operator\u27s financial responsibility requirement in the form of mandatory third-party insurance; (3) establishing a risk-based premium fund; and (4) creating a supplementary fund from firms that extract hydrocarbons in excess of a specific threshold level
SHORT TERM MICROBIAL COLONIZATION OF REPTILE ROADKILL
Little is known about how microbes such as bacteria and fungi in the environment tempoÂrally colonize common roadkill reptile carcasses (turtles and snakes). We opportunistically collected and deployed a variety of reptile carcasses often found deceased near roads, including an Eastern Ratsnake (Pantherophis alleghaniensis), an Eastern Box Turtle (Terrapene carolina), and a Snapping Turtle (Chelydra serpentina). We sampled bacteria communities of these carcasses daily for five conÂsecutive days. We enumerated the number of colony-forming units (CFUs) and characterized microbial distinct colonies using morphology and identification of dominant colonies using 16S rRNA sequencing across carcasses. Several ecologically relevant bacterial phyla were successfully identified colonizing and dominating carcasses differentially, including members of Actinobacteria, Firmicutes, and ProteoÂbacteria. We observed higher bacterial colonization (CFUs) for both terrestrial and aquatic turtles, T. carolina and C. serpentina, compared to P. alleghaniensis. This study provides baseline data on the temporal microbiology of deceased reptiles found on roads in the piedmont of North Carolina
Tip–sample interactions: Extraction of single molecular pair potentials from force curves
This article describes a method for extracting the true tip–sample potential from an experimental force curve in atomic force microscopy. This potential is not the negative integral of the force curve. Rather, the potential is a more complicated function of the force curve and cantilever spring constant. If information about the shape of the tip is known, a decorrelation may be performed to extract molecular pair potentials from the total tip–sample potential. Applications and limitations of this method are discussed
Resolved Spectroscopy of the Narrow-Line Region in NGC 1068: Kinematics of the Ionized Gas
We have determined the radial velocities of the [O III] emitting gas in the
inner narrow-line region (NLR) of the Seyfert 2 galaxy NGC 1068, along a slit
at position angle of 202 degrees, from STIS observations at a spatial
resolution of 0.1 arcsec and a spectral resolving power of approximately 1000.
We use these data to investigate the kinematics of the NLR within 6 arcsec (430
pc) of the nucleus. The emission-line knots show evidence for radial
acceleration, to a projected angular distance of 1.7 arcsec in most cases,
followed by deceleration that approaches the systemic velocity at a projected
distance of about 4 arcsec. We find that a simple kinematic model of biconical
radial outflow can match the general trend of observed radial velocities. In
this model, the emitting material is evacuated along the bicone axis, and the
axis is inclined 5 degrees out of the plane of the sky. The acceleration of the
emission-line clouds provides support for dynamical models that invoke
radiation and/or wind pressure. We suggest that the deceleration of the clouds
is due to their collision with a patchy and anistropically distributed ambient
medium.Comment: 18 pages, Latex, includes 3 figures in postscript, to appear in the
Astrophysical Journal Letter
Shear band formation in granular media as a variational problem
Strain in sheared dense granular material is often localized in a narrow
region called shear band. Recent experiments in a modified Couette cell
provided localized shear flow in the bulk away from the confining walls. The
non-trivial shape of the shear band was measured as the function of the cell
geometry. First we present a geometric argument for narrow shear bands which
connects the function of their surface position with the shape in the bulk.
Assuming a simple dissipation mechanism we show that the principle of minimum
dissipation of energy provides a good description of the shape function.
Furthermore, we discuss the possibility and behavior of shear bands which are
detached from the free surface and are entirely covered in the bulk.Comment: 4 pages, 5 figures; minor changes, typos and journal-ref adde
Review of the Ochsenius Theory for Salt Generation in the Transylvanian Basin, Romania
This short study aims to highlight contradictions in Ochsenius’s model for the basin-wide salt generation (Kara-Bogas bay desiccation). Without claiming completeness, and through numerous records cited from the specific literature, we attempt to point at crucial incoherencies in the classical evaporitic model. In our presupposition, these might have led our ancestors to conclude that basin-wide salt generation needs theoretically well-based models. This is emphatically true for the Transylvanian Basin,Romania.The selected records are basic for the specific topic. We checked their validity by logical reasoning and by literature references.As for salt generation, the classical Ochsenius model has been upheld for the generation of evaporates even though it has been known that there are records denying the exclusivity of the evaporation model. It has also been proven that deep-sea salt exists, yet terminology is reluctant to follow the new discoveries. If non-evaporitic salt generation exists, it entails that huge salt deposits may exist, which are not remnants of a desiccation process.These cannot be considered as part of the classical theory of evaporation.Former researchers left important but neglected records, which should have updated the model of Ochsenius by now. Well-documented historical observation uncovered some contradictions in the salt generation of the Transylvanian Basin, Romania.Hereby we list 10 important contradictions,which may reveal that the well-known theory of Ochsenius (i.e. drying of Kara Bogaz bay) ought to be challenged for the Transylvanian Basin
- …