Hot Site Research Articles

The Hot Tubb Folsom-Midland Site (41CR 10), Texas

The Hot Tubb site, located in the Monahans Dunes just off the southern High Plains of west Texas, has yielded Folsom and Midland projectile points, as well as badly fragmented and occasionally burned remains of Bison antiquus. Because these materials occur primarily on the surface of a deflation basin within an active sand dune, which also contains artifacts of later age, the Paleoindian component cannot be easily isolated, nor have attempts to determine its radiocarbon age been successful. Nonetheless, the distribution and density of the bone and diagnostic Folsom material indicate there is spatialandpossibly stratigraphic integrity to this component, which makes it possible to discern where and what Paleoindian activity may have occurred on site.We infer this was a small Folsom-age bison kill and processing locality of an estimated six animals. The lithic assemblage is marked by intensive reworking and even refluting of projectile points, suggesting that the supply of stone, originally acquired at sources at least 150 km distant, was low by the time of this occupation. That dearth of stone, the presence of Midland points, as well as a possible Midland point preform, may also shed some light on the longstanding ‘Folsom-Midland Problem.’

2D nanostructure of gold nanoparticles: An approach to SERS-active substrate

Monolayer well-ordered close-packed 2D nanostructures of gold nanoparticles were fabricated without using any capping reagent or surfactant. The area of the 2D nanostructure obtained was as large as several 100 s μm 2 to mm 2. The individual gold nanoparticles of the 2D nanostructure are not in contact depicting the possible surface active site (i.e. hot site). The SERS-activity was measured by using crystal violet molecules adsorbed on the 2D nanostructure. The estimated enhancement was found as much as 10 8. Size-dependent SERS intensity of the well-ordered 2D nanostructures is discussed in detail.

Comparison of metal–amino acid interaction in Phe–Ag and Tyr–Ag complexes by spectroscopic measurements

In this article, we have compared the metal–amino acid interactions in Tyr–Ag and Phe–Ag complexes through pH dependent SERS measurements. By analyzing the variation in relative intensities of SERS bands with the pH of the amino acid solution, we have obtained the orientation and conformation of the amino acid molecules on the Ag surface. The results obtained from our experimental studies are supported by the energy minimized structures and the observed charge distributions in different terminals of the molecules. This, in a way, shows that SERS measurements not only exhibit the interaction of the amino acid molecules with Ag clusters but also demonstrate their orientation around it. We have addressed a long standing query on whether the amine group is directly attached to the Ag surface along with the carboxylate group and π-electrons in these systems. In addition, pH dependent optical absorption and transmission electron microscopy measurements have been performed to understand the required conditions for the appearance of the SERS spectra in the light of the aggregation of metal particles and the number of hot sites in the sol. Our results confirm that the formation of hot sites in the sol plays a direct role in forming a stable Ag–ligand complex. Furthermore, the interaction kinetics of metal–amino acid complexes have been analyzed via both Raman and absorption measurements.

Determinants of protein stability and folding: Comparative analysis of beta‐lactoglobulins and liver basic fatty acid binding protein

A new energy decomposition approach, aimed at identifying residues playing a folding key role, has been applied here to three homologous proteins, belonging to the calycin superfamily, namely bovine and porcine beta-lactoglobulins and Liver basic fatty acid binding protein, sharing the same beta-barrel fold and different degree of sequence identities. All-atom, explicit solvent molecular dynamics simulations around the native conformation were used to generate, for each of the three proteins, energy maps which were further simplified through eigenvalue decomposition. Analysis of the components of the eigenvector associated with the lowest eigenvalue singled out those residues (hot sites) behaving as strongly interacting and possible nucleation centers. The results fit well with experimental folding data and, especially, with the analysis of side chain-side chain interaction conservation.

Scanning Near-Field Optical Microscopic Observation of Surface-Enhanced Raman Scattering Mediated by Metallic Particle-Surface Gap Modes

Samples consisting of a copper phthalocyanine (CuPc) thin film sandwiched between Au particles and a Ag film were prepared and their Raman scattering was investigated with a scanning near-field optical microscope (SNOM). The Raman intensity of CuPc was found to be greatly enhanced by the presence of the Au particles and takes a maximum on top of the particles. It was also found that the enhancement factor depends strongly on the diameter of Au particles and the excitation wavelength. With the aid of reflection-absorption spectra, which exhibited an absorption peak attributable to the gap mode of the particle–surface system, the observed behavior of the enhancement factor could be explained by the resonance of incident and scattered light to the gap mode. The present results clearly demonstrate that the gap between the metallic particle and surface is a hot site of Raman scattering.

ナノプラズモニクス

Several topics on nano-plasmonics are reviewed including hot site engineering, plasmonic crystals, plasmonic waveguides, plasmonic lithography, a perfect lens with a metal slab, and plasmonics in long-wavelength region.

Incubation regimes of cold-climate reptiles: the thermal consequences of nest-site choice, viviparity and maternal basking

Cold-climate reptiles show three kinds of adaptation to provide warmer incubation regimes for their developing embryos: maternal selection of hot nest sites; prolonged uterine retention of eggs; and increased maternal basking during pregnancy. These traits may evolve sequentially as an oviparous lineage invades colder climates. To compare the thermal consequences of these adaptations, I measured microhabitat temperatures of potential nest sites and actual nests of oviparous scincid lizards (Bassiana duperreyi), and body temperatures of pregnant and non-pregnant viviparous scincid lizards (Eulamprus heatwolei). These comparisons were made at a site where both species occur, but close to the upper elevational limit for oviparous reptiles in south-eastern Australia. Viviparity and maternal basking effort had less effect on mean incubation temperature than did maternal nest-site selection. Eggs retained in utero experienced bimodal rather than unimodal diel thermal distributions, but similar mean incubation temperatures. Often the published literature emphasizes the ability of heliothermic (basking) reptiles to maintain high body temperatures despite unfavourable ambient weather conditions; this putative ability is central to many hypotheses on selective forces for the evolution of viviparity. In cold climates, however, opportunities for maternal thermoregulation to elevate mean body temperatures (and thus, incubation temperatures) above ambient levels may be severely limited. Hence, at least over the broad elevational range in which oviparous and viviparous species live in sympatry, maternal selection of ‘hot’ nests may be as effective as is viviparity in providing favourable incubation regimes. © 2004 The Linnean Society of London, Biological Journal of the Linnean Society, 2004, 83, 145–155.

Use of close-range photogrammetry to characterize fracture surfaces

Abstract Natural fractures are characterized by rough surfaces and complex fluid flows. A large distribution of apertures (residual voids) within their walls and the presence of contact points produce heterogeneous flows (channelling). The resulting permeabilities, porosities or fluid-rock exchange surfaces cannot be realistically modelled by parallel and smooth plate models. It is therefore very important to better constrain models of the fracture planes : asperity heights and aperture distribution to be able to fix specific models of permeability in specific fracture void geometry. In this approach, a precise description of the fracture surface planes is given by providing some new quantitative data of surface roughness in the case of natural fractures. Studied fractures are sampled in a granite and a sandstone in the deep basement of the Hot Dry Rock site of Soultzsous-Forêts (Bas-Rhin, France). An original use of close-range photogrammetry is performed to quantify XYZ data on fracture walls. This methodology is presented as a non destructive, precise and accurate technology to quantify some digital terrain models (DTM) of the fracture plane topography. XYZ results are statistically treated in terms of surface roughness and tortuosity and are compared for different rocks to previous data obtained by mechanical profilometry. The results shows that the photogrammetric approach gives same order of asperity heights magnitudes as profilometry despite a shift towards more important values of roughness when close range photogrammetry uses relative autocorrelation models. The advantage of photogrammetry is that this technique gives very quick results and is non destructive when thin alteration or pulverulent deposits are present within fracture walls or in the rock matrix. The disadvantage is that a slight smoothing of data is inherent to an absolute model calibration. Finally only relative 300*300 DTM are finally chosen to match profilometry data because of their higher precision in terms of micro roughness description to compare natural fracture surfaces. In the objective of a classification of fracture roughness in specific geological contexts, the photogrammetric approach gives a good estimation of different classes of roughness in function of rock alteration and type.

Microbial infection affects egg viability and incubation behavior in a tropical passerine

Many avian species initiate incubation before clutch completion, which causes eggs to hatch asynchronously. This influences brood competitive dynamics and often results in nestling mortality. The prevailing hypotheses contend that parents incubate early because asynchronous hatching provides fitness benefits to parents or surviving offspring. An alternative idea is that early incubation is the best of a bad job because of the costs of delaying incubation to the viability of first-laid eggs. To explore this, we examined the potential for microbial infection, and the relative effects of infection and suboptimal development temperatures on the viability of pearly-eyed thrasher (Margarops fuscatus) eggs. We exposed newly laid eggs for 5 days at either end of a tropical altitudinal gradient and cleaned shells of half the eggs to reduce microbial growth. Uncleaned eggs were infected more than were cleaned eggs, and infection was greater for eggs exposed at the cool, humid site than at the hot, less humid site. Parentally incubated eggs, however, were not infected, suggesting that incubation limits infection. The consequence of exposure to infection and high ambient temperatures was a dramatic reduction in viability; cleaned eggs held at the cool site had the highest hatching success, which was significantly greater than for uncleaned eggs at this site and for cleaned eggs held at the hot site. This provides the first evidence that microbes can infect unincubated eggs of a wild bird, and that infection and ambient temperature act independently to reduce hatching success. These factors could affect avian life-history strategies in diverse habitats.

Porosity and fluid velocities in the upper continental crust (2 to 4 km) inferred from injection tests at the Soultz-sous-For�ts geothermal site1

A heat exchanger was created at the French Hot Dry Rock geothermal site using a doublet of boreholes at a depth of 3600–3800 m. After hydraulic stimulation, this exchanger was tested during a long-term circulation trial from July to November 1997. Tracer tests were carried out during the circulation trial. An analysis of the tracers indicates a connected porous volume in the range of 0.5 to 2.5 × 10 6 m 3 , with a connected porosity of the order of 0.9 to 2.3%. These values are one order of magnitude higher than values obtained by extrapolation from petrophysical investigation of the boreholes. This result is interpreted as being due to the connection of the major faults to a dense network of 2 nd -order structures. Fluid circulation velocities inferred from the tracer test are of the order of 0.25 to 0.36 m/h. Velocities derived from observation of the migration of fresh fluids after injection into the granite during stimulation tests are of the same order of magnitude (0.02 to 0.17 m/h), yielding hydraulic conductivity estimates of 6.6 10 −8 to 2.3 10 −6 m/s −1 . Both the pressure gradient during the circulation test and the density gradient are related to freshwater injection, and can be considered as possibly equivalent to temperature and hydraulic gradients in the Rhine graben, at least during some specific geological events such as the Alpine uplift phases. Thus, the test shows that fluid migration can occur in the upper continental crust exhibiting “reservoir” properties, and these should be taken into account in large-scale modelling. These properties are in good agreement with a proposed scenario of evolution involving active fluid migration during the Eocene (Alpine uplift phase). It also supports the hypothesis of seawater-derived saline fluids stored in old fractured shield rocks, which implies deep seawater circulation in the continental crust.

Porosity and fluid velocities in the upper continental crust (2 to 4 km) inferred from injection tests at the Soultz-sous-Forêts geothermal site

A heat exchanger was created at the French Hot Dry Rock geothermal site using a doublet of boreholes at a depth of 3600–3800 m. After hydraulic stimulation, this exchanger was tested during a long-term circulation trial from July to November 1997. Tracer tests were carried out during the circulation trial. An analysis of the tracers indicates a connected porous volume in the range of 0.5 to 2.5 × 10 6 m 3 , with a connected porosity of the order of 0.9 to 2.3%. These values are one order of magnitude higher than values obtained by extrapolation from petrophysical investigation of the boreholes. This result is interpreted as being due to the connection of the major faults to a dense network of 2 nd -order structures. Fluid circulation velocities inferred from the tracer test are of the order of 0.25 to 0.36 m/h. Velocities derived from observation of the migration of fresh fluids after injection into the granite during stimulation tests are of the same order of magnitude (0.02 to 0.17 m/h), yielding hydraulic conductivity estimates of 6.6 10 −8 to 2.3 10 −6 m/s −1 . Both the pressure gradient during the circulation test and the density gradient are related to freshwater injection, and can be considered as possibly equivalent to temperature and hydraulic gradients in the Rhine graben, at least during some specific geological events such as the Alpine uplift phases. Thus, the test shows that fluid migration can occur in the upper continental crust exhibiting “reservoir” properties, and these should be taken into account in large-scale modelling. These properties are in good agreement with a proposed scenario of evolution involving active fluid migration during the Eocene (Alpine uplift phase). It also supports the hypothesis of seawater-derived saline fluids stored in old fractured shield rocks, which implies deep seawater circulation in the continental crust.

High‐ResolutionChandraSpectroscopy of γ Cassiopeiae (B0.5e)

gamma Cas has long been famous for its unique hard X-ray characteristics. We report herein on a 53 ks Chandra HETGS observation of this target. An inspection of our spectrum shows that it is quite atypical for a massive star, with abnormally weak Fe XXV, XXVI lines, Ly-alpha lines of H-like species from Fe XVII, XXIII, XXIV, S XVI, Si XIV, Mg XII, Ne X, O VII, VIII, and N VII. Also, line ratios of the rif-triplet of for a few He-like ions XVII are consistent with the dominance of collisional atomic processes. Yet, the presence of Fe and Si fluorescence K features indicates that photoionization also occurs in nearby cold gas. The line profiles indicate a mean velocity at rest and a broadening of 500 km/s. A global fitting analysis of the line and continuum spectrum finds that there are 3-4 plasma emission components. The dominant hot (12 keV) component and has a Fe abundance of 0.22 solar. Some fraction of this component (10-30%) is heavily absorbed. The other 2-3 components, with temperatures 0.1, 0.4, 3 keV, are warm, have a nearly solar composition, a lower column absorption, and are responsible for most other emission lines. The strength of the fluorescence features and the dual-column absorption model for the hot plasma component suggest the presence near the hot sites of a cold gas structure with a column density of 10^23 cm^-2. Since this value is consistent with theoretical estimates of the vertical disk column of this star, these attributes suggest that the X-rays originate near the star or disk. It is possible that the Fe anomaly in the hot component is related to the First Ionization Potential effect found in coronal structures around active cool stars. This would be yet another indication that the X-rays -rays are produced in the immediate vicinity of the Be star.

Inferred role of natural fractures, veins, and breccias in development of the artificial geothermal reservoir at the Ogachi Hot Dry Rock site, Japan

At the Ogachi Hot Dry Rock (HDR) test site, located in a Neogene caldera, northeast Japan, two artificial reservoirs, the upper one at 700 m depth and the lower one at 1000 m depth, were created in granitic basement by hydraulic stimulation. The new fracture sets, forming the reservoirs, propagated in different directions, the upper one to the east and the lower one to the NNE. Water recovery rate from a production well penetrating the two reservoirs was at best 25%, which is very low compared to other HDR test sites such as Fenton Hill, United States, and Soultz, France. In order to understand these phenomena, natural fractures were investigated using mainly core samples from the production well. It was found that natural fractures in the upper and lower reservoirs are remarkably different: the upper reservoir, at depths less than 900 m, is more densely fractured and contains far fewer thick hydrothermal veins than in the lower reservoir. It is believed that these features are due to hydrothermal brecciation associated with Neogene caldera formation and that they could greatly affect the HDR reservoir system. Thick hydrothermal veins and andesite dykes are expected to loci for reservoir fracture propagation and major flow paths because the veins and dykes occupy a prominent fracture system whose orientation coincides well with that of the reservoir propagation. On the other hand, the intensely brecciated zone is not associated with any major flow paths.

An empirical assessment of IT disaster risk

Disasters have historically been associated with catastrophic events such as floods,fires, hurricanes, or earthquakes, but recent computer failures, such as the air trafficsystem failure at Washington Center, have broadened the definition of disaster—asany event causing significant disruption to operations, thereby threatening businesssurvival [9] With the incentives of cost-efficiency and competition driving businessto place more critical information assets into automated systems and networks [4],the loss or denial of assets required for normal operations can have a catastrophicimpact on a firm’s bottom line [2]. Such disasters may involve the loss of integrity orreliability in a critical dataset or in the means by which data are transported, manip-ulated, or presented. As firms grow more dependent on uninterrupted information system function-ing, disaster recovery (DR) is receiving increasing attention, and a growing numberof organizations are beginning to engage in DR planning. In addition to cold sites,reciprocal agreements, and other services, DR vendors market a service known as “hotsites,” designed to provide standby computer resources in the event that one or moresubscribers require an alternative computer center to process critical applications.Companies pay steep monthly subscription fees for hot-site facilities, into whichcompany departments can move, literally overnight, if required [6]. This requirementis usually prompted by an actual or perceived event that could render the subscriber’scomputer systems inoperable. The activation of hot site service is initiated throughthe formal declaration of a disaster. The definition of disaster varies by client, withhot site providers generally allowing a broad interpretation of the term. For example,some vendor clients declare disasters in order to provide backup data processing capa-bility during a planned relocation of their data center.Despite the vital necessity of uninterrupted IT capability for most of today’sorganizations, few empirical studies provide practitioners and academicians with a

Arsenic Tolerating Plants from Mine Sites and Hot Springs in the Semi‐Arid Region of Chihuahua, Mexico

AbstractPhytoremediation is an emergent field of great potential for the removal of metals, metalloids and other contaminants from soil, water and sediments. The use of native plants with high tolerance and capacity to accumulate the metal to be removed is a very convenient approach. High levels of arsenic (As) have been found at several natural sources in the northern arid and semi‐arid regions of Mexico. The state of Chihuahua is, among others, one in which As has been detected in sources of natural drinking water. The aim of the present work was to identify indigenous plants in the state of Chihuahua with As tolerance and accumulating capacity. Water samples from different mine sites and hot springs were inspected. At these sites, the As concentration varied in the range of 110–191 μg/l in water and 40–2100 μg/g in soils. A native plant identified as Eleocharis sp. (Cyperaceae), collected from the nearby surroundings of a hot spring site, was found to contain an As concentration of 301 μg/g. The arsenic bioconcentration (BCF) and translocation (TF) factors for this plant exceeded 1 (5.22 and 7.37, respectively), which classifies it as an arsenic‐tolerant plant with potential use in phytoextraction. The TF of Brickellia veronicaefolia, Nicotiana glauca and Baccharis salicifolia were above one, but they had very low BCF coefficients, which limited their potential to be considered for a phytoremediation process.

FGFR2 and WDR11 are neighboring oncogene and tumor suppressor gene on human chromosome 10q26

Oncogenes and tumor suppressor genes are clustered around recombination hot spots or fragile sites in the genome, because double-strand break is the common initial step in translocation, deletion and gene amplification. FGFR2 gene on human chromosome 10q26 is amplified in diffuse-type gastric cancer, while WDR11 gene on human chromosome 10q26 is disrupted in glial tumors. Here, we investigated genomic structure around FGFR2 and WDR11 loci. The FGFR2 gene, consisting of 21 exons, was located within nucleotide position 485637-605687 of NT_030764.5 (reverse orientation), and WDR11 gene was located within nucleotide position 6515786-6574126 of NT_008902.12 (forward orientation). Because nucleotide position 1-91397 of NT_030764.5 corresponded to nucleotide position 6639437-6748623 of NT_008902.12, FGFR2 and WDR11 genes were found to be closely linked in tail-to-tail manner with an interval of ca. 570 kb. Due to the deletion of exon 21 within FGFR2 amplicons, exon 21 is substituted by exon 20 or other aberrant exons in aberrant FGFR2 transcripts previously isolated from KATO-III, OCUM-2M and HSC43 cells. Mapping of aberrant exons and deletion junctions around the WDR11-FGFR2 locus in KATO-III and OCUM-2M cells revealed that inverted-type recombination occurred through end joining of the FGFR2 locus on one allele and that on the other allele. Amplification of FGFR2 gene with such recombination around exon 21 results in exclusion of WDR11 gene from the FGFR2 amplicon. Tumor suppressor genes closely linked to oncogenes might be excluded from amplicon through a breakage-fusion-bridge process during oncogene amplification.

Comparative analysis of MGE 412 patterns in 18 isogenic lines of Drosophila melanogaster

Comparative analysis of patterns of mobile genetic element 412 was conducted in 18 isogenic lines of Drosophila melanogaster isolated in three isogenic experiments in 1987 through 1999. Twelve "extra-hot" isogenization sites (in 15-18 lines) and 23 "hot" isogenization sites (> or = 10 lines) were found; of these, 19 occurred in the original heterogeneous line. These sites virtually do not overlap with hot induction sites of transposition. Sites of the latter group generally retain their positions during isogenization. It was shown that no more than 20% of the new sites were brought from the balancer by double recombination, while inbreeding and outbreeding caused 80% of them. Different factors were shown to have different hot isogenization sites. A similarity tree was constructed for the patterns of 18 isogenic lines. The maximum peak of the tree was very low (< 0.25), i.e., the isogenic lines are more similar to than different from one another. The tree was subdivided into subtrees. The division was in good agreement with the isogenization groups corresponding to individual isogenization experiments. Significant correlation was found between the total fragment length and the number of new sites per lines.

Impacts of off-road vehicles on nitrogen cycles in biological soil crusts: resistance in different U.S. deserts

Biological soil crusts are an important component of desert ecosystems, as they influence soil stability and fertility. This study examined and compared the short-term vehicular impacts on lichen cover and nitrogenase activity (NA) of biological soil crusts. Experimental disturbance was applied to different types of soil in regions throughout the western U.S. (Great Basin, Colorado Plateau, Sonoran, Chihuahuan, and Mojave deserts). Results show that pre-disturbance cover of soil lichens is significantly correlated with the silt content of soils, and negatively correlated with sand and clay. While disturbance appeared to reduce NA at all sites, differences were statistically significant at only 12 of the 26 sites. Cool desert sites showed a greater decline than hot desert sites, which may indicate non-heterocystic cyanobacterial species are more susceptible to disturbance than non-heterocystic species. Sandy soils showed greater reduction of NA as sand content increased, while fine-textured soils showed a greater decline as sand content increased. At all sites, higher NA before the disturbance resulted in less impact to NA post-disturbance. These results may be useful in predicting the impacts of off-road vehicles in different regions and different soils.

Surface electric variations induced by deep hydraulic stimulation: An example from the Soultz HDR site

We carried out monitoring of surface electric potential variations at the Soultz Hot Dry Rock site (France) during a stimulation experiment where 23 000 m3 of water were injected in granite at 5 km depth. We have observed a long‐period (9–10 days) potential variation with a maximum amplitude of ≈5 mV, thanks to the conductive well casing. The start of this anomalous potential coincides with that of the water injection and its magnitude increases as more water is injected before returning toward its original value after shut‐in. We interpret this anomalous potential as an electrokinetic effect which is caused by the injection of water circulating in deep fractures. We modeled the pressure distribution during the stimulation and obtained the surface SP using electrokinetic coupling relationships. We found that an in‐situ coupling coefficient of ≈−1 mV/MPa, at the low end of laboratory values, gives a good fit to the data.

Germination ecology of the weed Parthenium hysterophorus in eastern Ethiopia

SummaryGermination ecology of Parthenium hysterophorus, recently introduced to Ethiopia, was studied in a series of experiments. Viability of the seeds was greater than 50% after 26 months of burial in the soil indicating the potential build‐up of a substantial persistent soil seed bank. A short period of dry storage was sufficient to overcome a light requirement for germination in a minor fraction of the seeds. Likewise, seeds exhumed from burial showed an increase in germination ability in darkness over time, with a weak tendency for seasonal cyclicity in dormancy level at one of two sites. Germination occurred at the mean minimum (10°C) and maximum (25°C) temperatures of the collection sites, as well as over a wide range of fluctuating (12/2°C‐35/25°C) temperatures in light. No germination of P. hysterophorus seeds occurred at osmotic potentials &lt; ‐0.52 MPa (at 27°C), the species being less tolerant to moisture stress than sorghum grains. Most seedlings emerged from shallowly buried (&lt; 0.5 cm) seeds and none from more than 5 cm depth. Naturally dispersed seeds required about 60 days, at a hot lowland site, to start emergence despite the presence of adequate rainfall, and higher number of seedlings emerged in undisturbed plots than in hand hoed plots. These experiments and field observations suggest that there are no obvious climatic conditions that may limit the germination of Parthenium hysterophorus in Ethiopia, but a high moisture requirement of the seeds for germination could be the major factor limiting germination during the dry season.