Spatial Aspects of Restrictions on Registered Sex Offenders

Restrictions in the USA on registered sex offenders (RSOs) are examined from the spatial aspects. The long history of various restrictions imposed by government, particularly local ones, is covered in the introduction. Spatial aspects, such as delineation of zones from which certain activities or certain people are excluded is the focus. Then the nature of restrictions on RSOs is considered at the state, county and municipal level. Typical of restrictions are that RSOs are prohibited from moving into residence within a prescribed distance of certain features in a community. The distances are typically 1,000 feet but are quite variable. Typical proscribed venues are schools, parks and day care centers, but there can be many others such as bus stops. Spatial aspects of these restrictions, such as how offender locations are geocoded and represented and how proscribed venues are delineated is analyzed. Specific details and theoretical concerns related to the many problematic issues with RSO restrictions is presented. In particular questions of their constitutionality and efficacy are raised. The paper concludes with a discussion of the implications of RSO restrictions for the discipline of geography in general and for the evolution of increasingly precise methods of spatial analysis in particular.     

ESTIMATION OF ERRORS IN ABSORBANCE RATIO MEASUREMENTS

Ratio measurements are commonly used to address a variety of analytical problems in environmental,forensic and pharmaceutical laboratories.In absorbance ratioing techniques,analytical chemists rely onthe spectral features of the analyte(s)of interest.The absorbances at two wavelengths are monitored andthe ratio of these two absorbances is computed.This ratio is then used to confirm the identity of theanalyte(s)of interest,the purity of a product or the overlap of chromatographic peaks.These decisionsoften have far-reaching consequences(e.g.the identification of the source,biogenic or petrogenic,ofhydrocarbons in biological tissues or water).Given the cost and the liabilities associated with suchdecisions,it is unfortunate that these ratios are seldom reported with any statistical confidence.Thepurpose of this study is to delineate the parameters that affect absorbance ratio measurements.Themodels that can be used to estimate the statistical confidence in these measurements are derived andevaluated experimentally.The results show that these models can estimate the relative standard deviationsin absorbance ratios accurately.They can also estimate the effect of signal-to-noise ratio and the choiceof wavelengths on the precision of absorbance ratios.     

Modeling the transport and accumulation floating debris generated by the 11 March 2011 Tohoku tsunami

A global ocean circulation model is coupled to a particle-tracking model to simulate the transport of floating debris washed into the North Pacific Ocean by the Tohoku tsunami. A release scenario for the tsunami debris is based on coastal population and measured tsunami runup. Archived 2011/2012 hindcast current data is used to model the transport of debris since the tsunami, while data from 2008 to 2012 is used to investigate the distribution of debris on timescales up to 4 years. The vast amount of debris pushed into ocean likely represents thousands of years worth of ‘normal’ litter flux from Japan’s urbanized coastline. This is important since a significant fraction of the debris will be comprised of plastics, some of which will degrade into tiny particles and be consumed by marine organisms, thereby allowing adsorbed organic pollutants to enter our food supply in quantities much higher than present.     

An explicit solution for static unbounded helical dynamos

Abstract

The Lortz dynamo with helical symmetry is re-examined. It is shown that by imposing appropriate boundary conditions the set of possible solutions can be broken down into various classes characterized by the behavior of the mean magnetic field. It is found that, as the cylindrical radius, s, tends to zero, <B_Φ> ～ 0(s^j), <B_z> ～ const + 0(s^j?i), where j>5. It is proved that the azimuthal wavenumber associated with the j=5 class is necessarily equal to 2. The existence of at least one cylindrical surface inside which the dynamo is self-sustained is demonstrated. A new simple explicit solution is obtained. The topology the magnetic field is studied and three-dimensional pictures of the magnetic field lines are exhibited. Finally, a criterion for reversal of the magnetic field as a function of radius is ohtained and is applied to our solution.     

Photoelectrons in the upper atmosphere: A formulation incorporating effects of transport

An efficient scheme is described for computation of photoelectron energy spectra. The method, similar to one used in radiative transfer theory, incorporates effects due to spatial and angular redistribution of electrons. These effects play a dominant role at heights above 400 km.     

Cathodoluminescence petrography and isotope geochemistry of KT impact ejecta deposited 360 km from the Chicxulub crater, at Albion Island, Belize

The depositional and diagenetic history of Cretaceous–Tertiary (KT) impact ejecta deposited 360 km from the Chicxulub crater, at Albion Island, Belize, has been investigated using integrated cathodoluminescence and isotopic analyses. A quarry exposes 26 m of Upper Cretaceous Barton Creek Formation dolomitized marine limestone overlain by 16 m of dolomitized Albion Formation impact ejecta. The Albion Formation consists of a lower fine‐grained ≈1‐m‐thick spheroid bed and an upper 15‐m‐thick coarse conglomeratic diamictite bed. A 14‐event paragenetic sequence has been documented and used as a temporal framework to interpret chemostratigraphic trends in bulk rock δ¹⁸O, δ¹³C and ⁸⁷Sr/⁸⁶Sr. The uppermost surface of the Barton Creek Formation was subaerially exposed before the KT impact, as indicated by a brecciated palaeosol that caps upsection decreases in δ¹³C and δ¹⁸O. Small 1‐cm‐diameter spheroids in the spheroid bed exhibit vermicular crystalline textures but lack the concentric zonations common to accretionary lapilli. These spheroids are hypothesized originally to have been impact glass or reactive Ca and Mg oxide dusts that adhered to water vapour particles condensing from the cooling impact vapour cloud. The spheroids were dolomitized soon after deposition. The earliest dolomitization in the matrix sediments of the Albion Formation was also post‐depositional, replacing clays formed by devitrification of impact glass. Dolomite and clay ⁸⁷Sr/⁸⁶Sr exhibit a distinct symmetrical distribution in the spheroid bed ranging from 0·707745 to 0·707872. Although unproven, this may represent primary changes in the chemical composition of the impact glass. The limestone clasts in the diamictite bed were dolomitized before the KT impact and exhibit upsection decreases in bulk rock ⁸⁷Sr/⁸⁶Sr. This suggests that the clasts were excavated from strata equivalent in age or older than the Barton Creek Formation at locations closer to, or in, the Chicxulub crater.     

Vertical distribution of two sympatric labrid fishes in the Western Mediterranean and Eastern Atlantic rocky subtidal: local shore topography does matter

Changes in the shore topography (e.g. slope) occur at a scale of hundreds of meters in several locations in the Lusitanian and the Mediterranean Sea provinces. We tested whether differences in the bottom inclination might affect the vertical distribution patterns of two sympatric coastal labrid fishes, the rainbow wrasse Coris julis and the ornate wrasse Thalassoma pavo. Visual censuses were used to determine the distribution and abundance of these labrid species in high (≥30°) and low (≤3°) slope rocky substrates covered by brown macroalgae and at two different depths (shallow, 4–7 m, and deep 14–20 m). Pectoral fin aspect ratio was used as an estimate of swimming performance to potentially explain the patterns observed. Despite the intrinsic biogeographical differences in the overall density of T. pavo and C. julis, on steep coasts the ornate wrasse dominated in shallow waters, whereas the two species coexisted both in shallow and deeper depths on gentle slope coasts. These distribution patterns were consistent across locations, and fin aspect ratio was not a good predictor of between‐habitat use for wrasses. We show that, under specific topographical conditions, the depth segregation pattern seems to be an interactive segregation (likely related to resource competition) rather than a result of selective segregation due to morphological differences in the pectoral fin. Significant ecological changes might occur in locations where the density of T. pavo has recently increased as a result of water warming.     

Most similar neighbor imputation of forest attributes using metrics derived from combined airborne LIDAR and multispectral sensors

In the context of predicting forest attributes using a combination of airborne LIDAR and multispectral (MS) sensors, we suggest the inclusion of normalized difference vegetation index (NDVI) metrics along with the more traditional LIDAR height metrics. Here the data fusion method consists of back-projecting LIDAR returns onto original MS images, avoiding co-registration errors. The prediction method is based on non-parametric imputation (the most similar neighbor). Predictor selection and accuracy assessment include hypothesis tests and over-fitting prevention methods. Results show improvements when using combinations of LIDAR and MS compared to using either of them alone. The MS sensor has little explanatory capacity for forest variables dependent on tree height, already well determined from LIDAR alone. However, there is potential for variables dependent on tree diameters and their density. The combination of LIDAR and MS sensors can be very beneficial for predicting variables describing forests structural heterogeneity, which are best described from synergies between LIDAR heights and NDVI dispersion. Results demonstrate the potential of NDVI metrics to increase prediction accuracy of forest attributes. Their inclusion in the predictor dataset may, however, in a few cases be detrimental to accuracy, and therefore we recommend to carefully assess the possible advantages of data fusion on a case-by-case basis.     

Natural frequency and damping ratio of a vertically vibrated surface foundation

It is possible and common to obtain equivalent natural frequency and damping for a soil-foundation system from results of experimental or numerical analysis assuming the system has a single degree of freedom. Three approaches to extract natural frequency and damping were applied to the vertically vibrated soil-foundation system. The sensitivity of the computed natural frequency and damping to the soil properties was evaluated through parametric studies. About 10–20% of discrepancy in values of natural frequency was observed due to different approaches. The results help to assess the reliability of equivalent soil properties determined from the reported natural frequency of the system. Finally the results obtained using theoretical predictions with linear soil properties measured in situ were compared to those calculated from experimental data. The prediction and experimental results showed good agreements if the embedment of the foundation is neglected with stepped sine test but considered with impulse test.     

Drought 2002 in Colorado: An Unprecedented Drought or a Routine Drought?

The 2002 drought in Colorado was reported by the media and by public figures, and even by a national drought-monitoring agency, as an exceptionally severe drought. In this paper we examine evidence for this claim. Our study shows that, while the impacts of water shortages were exceptional everywhere, the observed precipitation deficit was less than extreme over a good fraction of the state. A likely explanation of this discrepancy is the imbalance between water supply and water demand over time. For a given level of water supply, water shortages become intensified as water demands increase over time. The sobering conclusion is that Colorado is more vulnerable to drought today than under similar precipitation deficits in the past.