Tornado shelter-seeking behavior and tornado shelter options among mobile home residents in the United States

Residents of 401 mobile homes in Georgia, Mississippi, Illinois, and Oklahoma were surveyed after they heard a tornado warning. Most residents (69%) did not seek shelter during the warning. Half of those who sought shelter went to the frame house of a friend, neighbor, or relative, and 25% of those sought shelter in a basement or underground shelter. Some of the places where residents sought shelter were of dubious quality, such as their own mobile home, another mobile home, or in an out-building. Twenty-one percent of mobile home residents believed that they had a basement or underground shelter available as shelter during a tornado warning, and about half of those said they would drive to the shelter. Residents said they would drive if the shelter was more than 200 m away. Fifteen percent actually had a basement or underground shelter suitable as shelter within 200 m of their mobile home, but only 43% of the residents would use those shelters. The most common reason cited for not using the shelters was that they did not know the people who lived there. Likewise, a frame house or other sturdy building was within 200 m of 58% of the mobile homes, but only 35% of the residents stated they would use those houses for shelter. Thirty-one percent of mobile home residents had a ditch that was at least 0.5 m deep within 200 m of the mobile home. However, 44% of these ditches had utility lines overhead, 23% had water in them, and 20% had trees overhead. The limited tornado shelter options among mobile home residents in the United States needs to be incorporated into safety instructions so that residents without nearby shelter are allowed to drive to safer shelter.     

A biomarker and δ15N study of thermally altered Silurian cyanobacterial mats

Early Silurian cherts from the Holy Cross and Bardzkie Mountains (Poland) contain abundant microfossils morphologically resembling contemporary cyanobacteria. Most of the organic matter preserved in the cherts is highly mature and extensively degraded because of biological decomposition and progressive thermal alteration. These processes may have changed the original morphology of the deposited microbial remains, so the microfossil origin could be easily misinterpreted. The cherts were therefore examined using organic geochemical and stable isotope techniques to provide support for the presence of cyanobacterial remains. The nitrogen isotopic composition of bulk sediments and extractable organic matter ranged from +0.1‰ to ?2.2‰ and from +1.8‰ to ?1.7‰, respectively. The δ¹⁵N values are thus in good agreement with a contribution of diazotrophic cyanobacteria for both locations. Biomarkers in the Holy Cross Mts. cherts included mid-chain branched monomethyl alkanes, indicative of a cyanobacterial contribution. However, molecular fossils of a cyanobacterial origin were not detected in the Bardzkie Mts. cherts, most likely because of the greater maturity than those from the Holy Cross Mts.     

Faint Lyman-break galaxies as a crucial test for galaxy formation models

It has recently been shown that galaxy formation models within the Λ cold dark matter cosmology predict that, compared to the observed population, small galaxies (with stellar masses  <10¹¹ M_⊙  ) form too early, are too passive since   z ∼ 3  and host too old stellar populations at   z = 0  . We then expect an overproduction of small galaxies at   z ≳ 4  that should be visible as an excess of faint Lyman-break galaxies. To check whether this excess is present, we use the morgana galaxy formation model and grasil spectrophotometric  +  radiative transfer code to generate mock catalogues of deep fields observed with Hubble Space Telescope Advanced Camera for Surveys. We add observational noise and the effect of Lyman α emission, and perform colour–colour selections to identify Lyman-break galaxies. The resulting mock candidates have plausible properties that closely resemble those of observed galaxies. We are able to reproduce the evolution of the bright tail of the luminosity function of Lyman-break galaxies (with a possible underestimate of the number of the brightest i -dropouts), but uncertainties and degeneracies in dust absorption parameters do not allow to give strong constraints to the model. Besides, our model shows a clear excess with respect to observations of faint Lyman-break galaxies, especially of   z ₈₅₀∼ 27 V   -dropouts at   z ∼ 5  . We quantify the properties of these 'excess' galaxies and discuss the implications: these galaxies are hosted in dark matter haloes with circular velocities in excess of 100 km s⁻¹, and their suppression may require a deep rethinking of stellar feedback processes taking place in galaxy formation.     

The spatial evolution of stellar structures in the Large Magellanic Cloud

We present an analysis of the spatial distribution of various stellar populations within the Large Magellanic Cloud (LMC). We combine mid-infrared selected young stellar objects, optically selected samples with mean ages between ∼9 and ∼1000 Myr and existing stellar cluster catalogues to investigate how stellar structures form and evolve within the LMC. For the analysis we use Fractured Minimum Spanning Trees, the statistical Q parameter and the two-point correlation function. Restricting our analysis to young massive (OB) stars, we confirm our results obtained for M33, namely that the luminosity function of the groups is well described by a power law with index −2, and that there is no characteristic length-scale of star-forming regions. We find that stars in the LMC are born with a large amount of substructure, consistent with a two-dimensional fractal distribution with dimension     and evolve towards a uniform distribution on a time-scale of ∼175 Myr. This is comparable to the crossing time of the galaxy, and we suggest that stellar structure, regardless of spatial scale, will be eliminated in a crossing time. This may explain the smooth distribution of stars in massive/dense young clusters in the Galaxy, while other, less massive, clusters still display large amounts of structure at similar ages. By comparing the stellar and star cluster distributions and evolving time-scales, we show that infant mortality of clusters (or 'popping clusters') has a negligible influence on the galactic structure. Finally, we quantify the influence of the elongation, differential extinction and contamination of a population on the measured Q value.     

Eocene–Miocene carbon-isotope and floral record from brown coal seams in the Gippsland Basin of southeast Australia

The carbon-isotope and palynological record through 580 m thick almost continuous brown coal in southeast Australia's Gippsland Basin is a relatively comprehensive southern hemisphere Middle Eocene to Middle Miocene record for terrestrial change. The carbon isotope δ¹³C_coal values of these coals range from ? 27.7‰ to ? 23.2. This isotopic variability follows gymnosperm/angiosperm fluctuations, where higher ratios coincide with heavier δ¹³C values. There is also long-term variability in carbon isotopes through time. From the Eocene greenhouse world of high gymnosperm-heavier δ¹³C_coal values, there is a progressive shift to lighter δ¹³C_coal values that follows the earliest (Oi1?) glacial events around 33 Ma (Early Oligocene). The overlying Oligocene–Early Miocene brown coals have lower gymnosperm abundance, associated with increased %Nothofagus (angiosperm), and lightening of isotopes during Oligocene cooler conditions.The Miocene palynological and carbon-isotope record supports a continuation to the Oligocene trends until around the late Early Miocene (circa 19 Ma) when a warming commenced, followed by an even stronger isotope shift around 16 Ma that peaked in the Middle Miocene when higher gymnosperm abundance and heavier isotopes prevailed. The cycle between the two major warm peaks of Middle Eocene and Middle Miocene was circa 30 Ma long. This change corresponds to a fall in inferred pCO₂ levels for the same period. The Gippsland data suggest a link between gymnosperm abundance, long-term plant δ¹³C composition, climatic change, and atmospheric pCO₂. Climatic deterioration in the Late Miocene terminated peat accumulation in the Gippsland Basin and no further significant coals formed in southeast Australia.The poor correspondence between this terrestrial isotope data and the marine isotope record is explained by the dominant control on δ¹³C by the gymnosperm/angiosperm abundance, although in turn this poor correspondence may reflect palaeoclimate control. From the brown coal seam dating, the coal appears to have accumulated during a considerable part of the allocated 30 Ma Cenozoic time period. These brown coal carbon isotope and palynological data appear to record a more gradual atmospheric carbon isotope change compared to the marine record.     

Legal challenges to the management of transboundary watercourses in Central Asia under the conditions of Eurasian Economic Integration

Worldwide experience has shown that interstate economic integration can help states in strengthening of management of transboundary waters and international water law serves as a reference for developing of relevant interstate cooperation. Transboundary waters in Central Asia play important role in the economic cooperation among riparian states, including those who are members of the Eurasian Economic Union (EAEU). At the current stage of transboundary waters management in Central Asia, the obsolete legal status is evident. The international water law sources developed under the United Nations’ auspices have no binding application due to luck of formal membership of the EAEU states in these treaties. Also the regional set of regulations, especially for the Aral Sea Basin, needs further enhancement and more efficient implementation. The bilateral interstate regulatory framework of the managemennt of waters shared by EAEU states in Central Asia requires development of additional rules to enable better accommodation of challenges existing in terms of the current interstate cooperation. Having said that can one further assume that EAEU could serve as a new legal framework for more effective cooperation on transboundary watercourses in Central Asia? The answer might be yes, but… the current stage of the legal framework for cooperation on transboundary waters within the EAEU requires sufficient enhancements in terms of developing its legal and institutional framework. The first condition for EAEU to serve as framework for cooperation on transboundary waters of Central Asia is to strengthen the regulatory framework for the cooperation of EAEU member states regarding environmental issues in general and transboundary water relations in particular, able to accommodate two main goals: environmental protection on the one hand and economic development on the other hand. The EAEU legal framework shall also lead to improvement of existing institutional cooperation and a dispute settlement mechanism on transboundary waters shared by the member states of the EAEU.     

Extreme events,trends, and variability in Northern Hemisphere lake-ice phenology (1855–2005)

Often extreme events, more than changes in mean conditions, have the greatest impact on the environment and human well-being. Here we examine changes in the occurrence of extremes in the timing of the annual formation and disappearance of lake ice in the Northern Hemisphere. Both changes in the mean condition and in variability around the mean condition can alter the probability of extreme events. Using long-term ice phenology data covering two periods 1855–6 to 2004–5 and 1905–6 to 2004–5 for a total of 75 lakes, we examined patterns in long-term trends and variability in the context of understanding the occurrence of extreme events. We also examined patterns in trends for a 30-year subset (1975–6 to 2004–5) of the 100-year data set. Trends for ice variables in the recent 30-year period were steeper than those in the 100- and 150-year periods, and trends in the 150-year period were steeper than in the 100-year period. Ranges of rates of change (days per decade) among time periods based on linear regression were 0.3−1.6 later for freeze, 0.5−1.9 earlier for breakup, and 0.7−4.3 shorter for duration. Mostly, standard deviation did not change, or it decreased in the 150-year and 100-year periods. During the recent 50-year period, standard deviation calculated in 10-year windows increased for all ice measures. For the 150-year and 100-year periods changes in the mean ice dates rather than changes in variability most strongly influenced the significant increases in the frequency of extreme lake ice events associated with warmer conditions and decreases in the frequency of extreme events associated with cooler conditions.     

Mixed land use and obesity: an empirical comparison of alternative land use measures and geographic scales

Obesity is a growing epidemic in the United States. Walkable neighborhoods, characterized as having the 3Ds of walkability (population Density, land use Diversity, and pedestrian-friendly Design), have been identified as a potentially promising factor to prevent obesity for their residents. Past studies examining the relationship between obesity and walkability vary in geographic scales of neighborhood definitions and methods of measuring the 3Ds. To better understand potential influences of these sometimes arbitrary choices, we test how four types of alternative measures of land use diversity measured at three geographic scales relate to body mass index for 4960 Salt Lake County adults. Generalized estimation equation models demonstrate that optimal diversity measures differed by gender and geographic scale and that integrating walkability measures at different scales improved the overall performance of models.     

Evidence of early Holocene closed-basin conditions in the Huron-Georgian basins from within the North Bay outlet of the upper Great Lakes

Sub-bottom profiling and coring were undertaken at eight sub-basins along the lower French River and at five small lakes near North Bay, Ontario, to collect stratigraphical and chronological evidence to investigate whether lakes occupying the Huron–Georgian basins during the early- to mid-Holocene became hydrologically closed. All of the coring sites are located within the route of the North Bay outlet that carried outflow from the upper Great Lakes during this period. Sand beds containing organic detritus are present within five cores from Muskrat, Crombie and Deep bays that otherwise are composed of glaciolacustrine rhythmites or fine-grained lacustrine deposits. These sand beds are interpreted to represent intervals when water levels within the sub-basins were lower than present, based on chronology, sediment texture, and macrofossil assemblages. It is inferred that the water surface in the Huron–Georgian basins fell below the level of the Dalles Rapids sill isolating the lower French River sub-basins from the large lake. A core from Depensier Lake, North Bay, contains an organic-rich sand interval within a thicker sand unit barren of organic materials. Macrofossils within this organic-rich interval are interpreted to be evidence of substantially diminished flow through the North Bay outlet channel. Radiocarbon dates of terrestrial macrofossils provide correlation of the sand beds between the French River cores as well as with the organic-rich sand in the Depensier Lake core. The possibility that the sand beds in the French River cores represent flood deposits rather than evidence of hydrologically closed conditions is considered, but rejected, based on the occurrence of multiple peaty layers and the record of shallow water conditions inferred from macrofossils within the upper sand bed of core MUS1, Muskrat Bay, in combination with the evidence of quiescent depositional conditions from similarly aged macrofossils in the core from Depensier Lake. Eight radiocarbon dates from the French River cores are incorporated into an elevation-age plot of paleo-indicators of water levels in the Huron–Georgian basins, using additional data from the literature. This plot and stratigraphic evidence from the Muskrat Bay cores indicates that separate closed-basin intervals occurred between 9.0 and 8.4, and 9.5 and 9.3 ka cal BP (~ 8.1 and 7.6, and ~ 8.5 and 8.3 ka BP). The occurrence of these two closed-basin intervals between 9.6 and 8.4 ka cal BP (~ 8.7 and 7.6 ka BP) implies that run-off derived exclusively from precipitation within the non-glaciated portions of the upper Great Lakes drainage basins was likely insufficient at this time to support an open-basin lake hydrology during the contemporary climate, which was colder and drier than present, without being supplemented from glacial Lake Agassiz overflow and/or Laurentide Ice Sheet meltwater.