Abstract. The aim of this study was to estimate the distance Mississippi patients must travel to access hospital-based emergency rooms (ERs) and to determine whether an association exists between geographic distance and ER utilization. To that end, great circle distances between Census Block Group Centroid Points and 89 hospitals with emergency departments were calculated for the State of Mississippi. Data on the socio-demographic characteristics of each block group came from the 2000 US Census data. Logistic regression analyses were conducted to test if there was any association between ER utilization and travel distance. Compared to the national benchmark of 35.7%, more than one in two (56.7%), or 1,612,762 Mississippians visited ERs in 2003 with an estimated 6.1 miles per person annual travel for this purpose. The majority of the target population (54.9%) was found to live within 5 miles of hospitals with ERs. Logistic analyses revealed that block groups associated with less miles traveled to hospitals with ERs had a higher proportion of African Americans, impoverished people, female householders, people with more than 12 years education, people older than 65 years, people with high median house values, and people without employment. Twenty-nine of the 89 hospitals (33%) providing ER care in Mississippi were found to be in areas with above-average ER utilization rates. These hospitals served a smaller geographical area (28% of the total) but had a greater proportion of visitors (57%) and served a higher percentage (37%) of the state population. People in areas served by the less utilized ERs traveled more miles to be cared for (7.1 miles vs 5.4 miles; p<0.0001). Logistic regression analysis revealed that shorter distances were associated with increased use of the ERs, even after controlling for socio-demographic factors. The conclusion is that Mississippi ERs are typically located in block groups with higher percentages of disadvantaged residents and that people in these areas are more likely to utilize ER services. Our data suggest that the geographical distance has an impact on ER utilization, especially by reducing utilization in disadvantaged block group areas. Disadvantaged persons living near ER hospitals (<5 miles) were found to be more likely to utilize the ER services. Geographic distance should therefore be considered when planning state-wide ER programmes for disadvantaged populations.

Summary Permeability data from Permian dolomitized shallow-water platform carbonate outcrops in west Texas and New Mexico exhibit two to five orders of magnitude variability, most of which occurs within distances of a few feet [1 to 2 m] within single rock-fabric units. A variety of longer-range features are also observed, including vertical interbed average-permeability contrasts, 140- to 180-ft [42- to 54-m] lateral periodicities, and up to 2,700-ft [810-m] lateral trends. The short-range heterogeneities can be modeled with K-Bessel semivariograms having asymptotic power-law behavior at the origin. The periodicities can be modeled with "hole-effect" J-Bessel semivariograms. Stochastic two-dimensional areal and vertical cross-section models explore the effects of these heterogeneities. Fluid-flow simulations demonstrate that some long-range features control overall flow behavior even when short-range variability composes most of the variance. The short-range heterogeneities produce local smearing of displacement fronts. Introduction For more than 10 years the Bureau of Economic Geology (BEG), The U. of Texas, Austin (UT), has been collecting petrophysical data from carbonate outcrops in west Texas and New Mexico to advance knowledge of the geological, petrophysical, geostatistical, and fluid-flow aspects of this important class of hydrocarbon reservoir rocks.1–6 Most of this work has been conducted in Permian dolomitized shallow-water platform carbonate systems of the San Andres, Grayburg, and Victorio Peak (a Clear Fork equivalent) formations. The subsurface equivalents of these outcrop successions contain a majority of the hydrocarbon resources in the Permian Basin of west Texas and New Mexico and more than 17 billion [&gt;2.7 billion?m3] of remaining mobile oil.7 Although particularly applicable to Permian Basin reservoirs, these outcrops provide insight into reservoir architecture and heterogeneity in highly cyclic shallow-water platform carbonate successions around the world. The prolific Permian Khuff carbonate reservoirs of the Middle East, for example, are close analogs. This paper is focused on two outcrops: a San Andres outcrop at Lawyer Canyon, Algerita Escarpment, Guadalupe Mountains, New Mexico, and a Victorio Peak outcrop, Apache Canyon, Sierra Diablo Mountains, Texas (Fig. 1). Outcrops of the San Andres formation in the Guadalupe Mountains form a 17-mile [27-km] continuous exposure along the Algerita Escarpment. Approximately parallel to depositional dip, this section displays a spectrum of cyclic, middle to outer platform carbonate facies successions. Studies of this shallow-water carbonate platform succession based on the application of modern sequence stratigraphic concepts have created a basis for modeling of San Andres reservoirs.4 The Lawyer Canyon area, the locale for most of the measurements described in this article, exposes the ramp-crest segment of the lower San Andres platform. Cycles in the ramp crest comprise basal mudstones and wackestones and capping grainstones and grain-dominated packstones.4 Lawyer Canyon is perhaps the most thoroughly sampled carbonate outcrop in the world, at least in terms of petrophysical measurements relevant to fluid-flow modeling. The earliest known sampling at this location was conducted by Shell Oil Co. in 1969-1971.8 Sampling by the BEG and UT at Lawyer Canyon began in 1988.9 The BEG data set has been augmented with measurements collected by Chevron Petroleum Technology Co.10 and previously unpublished data collected by Mobil Technology Co. in 1992-1993. The combined ramp-crest data set at Lawyer Canyon (there are additional outer ramp data at Lawyer Canyon that we do not discuss here11) includes approximately 5,000 mechanical field permeameter (MFP) measurements, 1,200 plug samples, 830 natural gamma-ray measurements, and a variety of descriptive parameters. In this article we examine four horizontal transects of MFP data designed to reveal patterns of permeability heterogeneity that cannot be observed in vertical wells (Fig. 2). We also consider in less detail six vertical MFP transects. The transects sample three different grainstone units, the highest permeability rock fabric at Lawyer Canyon.4 Each transect is fully contained within a single grainstone unit. Outcrops in Apache Canyon provide a 1.5-mile [2.4-km] continuous exposure of the Victorio Peak formation along an oblique-to-dip section immediately landward of the platform margin. Ongoing studies of the Victorio Peak succession reveal thin cycles packaged into thicker cycle sets and sequences. Petrophysical data for this study were obtained from 414 1-in.-diameter [2.54-cm] plug samples collected in 1997 from a horizontal transect in a single high-frequency cycle at the base of a high-frequency sequence. The transect was designed to investigate petrophysical heterogeneity in a transition from tidal-flat facies updip to subtidal grainstones and grain-dominated packstones downdip. General Observations The MFP data from the four horizontal Lawyer Canyon transects are displayed in Fig. 3. The 414 Apache Canyon samples were each cut into as many 1-in.-long [2.54-cm] pieces as possible, producing 689 plugs. The Apache Canyon permeability transect is shown in Fig. 4. The Apache Canyon porosity transect (not shown) has similar properties. Perhaps the most striking feature of these data is the high degree of variability. The Lawyer Canyon transects have at least two orders of magnitude variation within single grainstone units. One transect, H1, exhibits more than three orders of magnitude variation. The Apache Canyon transect, which spans a transition from subtidal to tidal-flat facies, has five orders of magnitude variability. The larger variability at Apache Canyon is related to the larger range of rock fabrics sampled, but it is also due to the different permeability measurement methods. The lower limit of MFP measurements at Lawyer Canyon is about 1 md [9.87E-04 µm2]; the lower limit of plug permeability data at Apache Canyon is 0.01 md [9.87E-06 µm2]. Table 1 summarizes the permeability data from these five transects. The Apache Canyon transect stands out from the others; it has a smaller geometric average and a larger variance than any of the Lawyer Canyon transects. The smaller mean permeability at Apache Canyon is consistent with the generally muddier rocks sampled in that transect. The Lawyer Canyon averages, especially in transect H2b, might be slightly overestimated because of the inability of the MFP to measure permeabilities less than 1 md [&lt;9.87E-04 µm2].

For the first time a global meeting on hepatitis A virus (HAV) infection as vaccine preventable disease was organized at the end of 2007. More than 200 experts from 46 countries gathered to investigate the changing global HAV epidemiology reflecting the increasing numbers of persons at risk for severe clinical disease and mortality from HAV infection. The benefits of childhood and adult hepatitis A (HepA) vaccination strategies and the data needed by individual countries and international health organizations to assess current HepA prevention strategies were discussed. New approaches in preventing HAV infection including universal HepA vaccination were considered. This introductory paper summarizes the major findings of the meeting and describes the changing epidemiology of HAV infections and the impact of HepA vaccination strategies in various countries. Implementation of HepA vaccination strategies should take into account the level of endemicity, the level of the socio-economic development and sanitation, and the risk of outbreaks. A stepwise strategy for introduction of HepA universal immunisation of children was recommended. This strategy should be based on accurate surveillance of cases and qualitative documentation of outbreaks and their control, secure political support on the basis of high-quality results, and comprehensive cost-effectiveness studies. The recognition of the need for increased global attention towards HepA prevention is an important outcome of this meeting.

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