Isotopic analysis of belemnites and brachiopods from the Cretaceous (Albian) Hunstanton Red Chalk Formation (Hunstanton,Norfolk, UK)

Cretaceous brachiopods (Moutonithyris dutempleana) and belemnites (Neohibolites minimus) from the (Albian) Hunstanton Red Chalk Formation (Hunstanton, UK) were isotopically analysed with the aim of identifying palaeoecological and palaeotemperature trends. Shell preservation was assessed via thin section petrography and geochemical analyses. Oxygen isotopic compositions (and corresponding temperature interpretations) of well-preserved belemnites are similar in comparison to the brachiopod shells. Assuming calcite precipitation in isotopic equilibrium, they are interpreted to have occupied the same or similar warm (15–19 °C) shallow marine environment. Further, these findings indicate that the belemnites mineralised in relatively warm waters and not in deep and cool waters as suggested for some belemnite species. The isotope data are thus inconsistent with the belemnites being associated with a cool water pulse, contrasting with events associated with the Cenomanian chalks. A difference δ¹³C between the belemnites and brachiopods is interpreted to originate from differences in metabolic rates.     

Modeling fractures as interfaces with nonmatching grids

We consider a model for fluid flow in a porous medium with a fracture. In this model, the fracture is treated as an interface between subdomains, on which specific equations have to be solved. In this article, we analyze the discrete problem, assuming that the fracture mesh and the subdomain meshes are completely independent, but that the geometry of the fracture is respected. We show that despite this nonconformity, first-order convergence is preserved with the lowest-order Raviart–Thomas(-Nedelec) mixed finite elements. Numerical simulations confirm this result.     

Magnetic tracers,a probe of the solar convective layers

Abstract

A meridional circulation of sunspots has been measured through the digital analysis of the Meudon spectroheliograms from 1978 to 1983. Old and young sunspots follow a zonal meridional circulation, in several bands of latitude, in which two adjacent bands have opposite motions. This meridional circulation pattern is time-dependent. Using the H _α filaments as magnetic field tracers, a large-scale magnetic pattern has been found that was also obtained independently by direct measurement of the magnetic field (Hoeksema, 1988).

The coincidence of a large-scale magnetic pattern with a zonal meridional circulation suggests the existence of azimuthal rolls below the surface, and these azimuthal rolls can explain a number of properties of the solar cycle. New rolls occur with increasing proximity to the Equator, thereby indicating the direction of propagation of the dynamo wave. The occurrence of rolls is very favorable to the emergence of the magnetic regions. The rolls also influence the magnetic complexity of the active regions. They modulate the surface rotation through the Coriolis force, which accelerates or decelerates the fluid particles. They therefore offer a plausible explanation of the torsional oscillation pattern.

There are a number of problems raised by such an unexpected circulation pattern: for example, the coexistence of axisymmeric rolls with hypothetical giant cells, the location of the dynamo source below or within the convective zone, and the coupling of the radiative interior and the convective layers. To resolve these important issues, continuous observational studies are needed of the manifestation of solar activity, as well as of radius and luminosity variations. So, we have aimed our paper at an audience of theoreticians in the hope that they take up the challenges we describe.     

Coastal Impacts of the March 11th Tohoku, Japan Tsunami in the Galapagos Islands

On March 11, 2011 at 5:46:23 UTC (March 10 11:46:23 PM Galapagos Local Time), the M_w 9.0 Great East Japan Earthquake occurred near the Tohoku region off the east coast of Japan, spawning a Pacific-wide tsunami. Approximately 12,000 km away, the Galapagos Islands experienced moderate tsunami impacts, including flooding, structural damage, and strong currents. In this paper, we present observations and measurements of the tsunami effects in the Galapagos, focusing on the four largest islands in the archipelago; (from west to east) Isabela, Santiagio, Santa Cruz, and San Cristobal. Access to the tsunami affected areas was one of the largest challenges of the field survey. Aside from approximately ten sandy beaches open to tourists, all other shoreline locations are restricted to anyone without a research permit; open cooperation with the Galapagos National Park provided the survey team complete access to the Islands coastlines. Survey locations were guided by numerical simulations of the tsunami performed prior to the field work. This numerical guidance accurately predicted the regions of highest impact, as well as regions of relatively low impact. Tide-corrected maximum tsunami heights were generally in the range of 3–4 m with the highest runup of 6 m measured in a small pocket beach on Isla Isabela. Puerto Ayora, on Santa Cruz Island, the largest harbor in the Galapagos experienced significant flooding and damage to structures located at the shoreline. A current meter moored inside the harbor recorded relatively weak tsunami currents of less than 0.3 m/s (0.6 knot) during the event. Comparisons with detailed numerical simulations suggest that these low current speed observations are most likely the result of data averaging at 20-min intervals and that maximum instantaneous current speeds were considerably larger. Currents in the Canal de Itabaca, a natural waterway between Santa Cruz Island and a smaller island offshore, were strong enough to displace multiple 5.5-ton navigation buoys. Numerical simulations indicate that currents in the Canal de Itabaca exceeded 4 m/s (~8 knots), a very large flow speed for a navigational waterway.     

Island Exceptionalism and International Maritime Conflicts

Scholars have argued that due to their special geographical circumstances, island states develop a different relationship with maritime space than their continental counterparts. This is generally attributed both to island residents’ greater access to and benefit from oceanic resources and also to the metaphysical qualities of life that uniquely develop on islands. This article investigates deeper into the phenomenon of geographically determined island exceptionality by considering whether island states and mainland states truly behave differently when it comes to their treatment of and behavior in maritime spaces. Through an analysis of disputed areas in the International Correlates of War maritime data, I consider whether island states are more likely to try and confirm sovereignty over disputed maritime waters than mainland states. My examination of disputed maritime areas in the Western Hemisphere and Europe from 1900 to 2001 shows that indeed island states are both more likely to try and settle a disputed maritime area, whether by force or by negotiated resolution. This finding is then used to raise new questions about the geographic differences that characterize island states in the world political system.     

A Regional Measure of Neighborhood Multiple Environmental Deprivation: Relationships with Health and Health Inequalities

The health impacts of simultaneous exposure to multiple adverse environmental factors are of concern in the United Kingdom. UK-wide indicators exist, but context-specific finer resolution measures are lacking. An environmental deprivation index was developed for 398 neighborhoods (average population = 760) in a Scottish council area, including measures of air pollution, noise pollution, traffic environment, undesirable land uses, and crime. Adverse environmental conditions were related to ill health in the region and implicated in wider socioeconomic health inequalities. The results suggest an independent role for environmental deprivation in explaining poor health and health inequalities.     

Sex Offender Residential Movement Patterns: A Markov Chain Analysis

This article introduces a new approach to the analysis of changes in sex offender residences over time. Using a Markov chain framework, we analyze residential movement patterns of registered sex offenders in Hamilton County, Ohio, over a three-year period (2005–2007). Results indicate a 46 percent reduction in offenders violating spatial restriction zone policy as compared to a counterfactual case where offenders move as a function of housing distributions. Strong legacy effects are also found as offenders previously in violation of restriction policies move into other restricted zones at a higher rate than offenders who were previously in compliance with the policy. Parcels that previously were home to registered offenders also continue to attract offenders in future periods. Although we find differences in the probabilities of attracting offenders for parcels outside and inside restricted zones that are consistent with offender restrictive policies, these differences are actually significantly smaller than what holds under the counterfactual. Parcels in restricted zones continue to attract offenders at a higher rate than expected, despite the policy restrictions.     

Greening U.S. National Parks: Expanding Traditional Roles to Address Climate Change

The U.S. National Park Service has embarked on a new campaign to address climate change. This directive includes new programs to encourage visitors to change their behaviors once they return home. By becoming involved in issues that go beyond park boundaries, these changes mark a shift in how the National Park Service fulfills its mission. This article explores how these efforts evolved and the possible implications to the visitors being exposed to a new message. Visitors were surveyed in Denali National Park and Preserve in Alaska. The results revealed that the majority of those surveyed support these new efforts by the National Park Service.     

Transformation of Trichloroethylene to Predominantly Non‐Regulated Products under Stimulated Sulfate Reducing Conditions

Anaerobic microcosms containing sediment and water were amended to generate a range of mass loadings of FeS. Microcosms were then spiked with trichloroethylene (TCE) and the concentration of TCE and possible volatile reaction products monitored over time. The lowest yields of TCE, as well as the lowest yields of reaction products regulated under the Safe Drinking Water Act (i.e., dichloroethylene isomers and vinyl chloride), were observed at FeS mass loadings at or above 20 g/L. Sixty eight days after spiking with TCE, selected microcosms were amended with sulfate and lactate, or sulfate, Fe(II), and lactate, and the effect of these amendments on TCE transformation and yield of regulated products was compared to microcosms that did not receive any amendments. Addition of sulfate, Fe(II), and lactate led to the greatest improvement on TCE depletion rates and the lowest yields of regulated reaction products compared with addition of sulfate and lactate, or no amendments. Analysis of kinetic modeling suggests that microbial and abiotic processes acted in concert to promote TCE transformation to a relatively low yield of regulated products in microbially active microcosms that contained high mass loadings of FeS.