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In massive objects, such as galaxy clusters, the turbulent velocity dispersion, $\sigma_\mathrm{turb}$, is tightly correlated to both the object mass, $M$, and the thermal energy. Here, we investigate whether these scaling laws extend to lower-mass objects in dark-matter filaments. We perform a cosmological zoom-in simulation of a filament using an adaptive filtering technique for the resolved velocity component and a subgrid-scale model to account for the unresolved component. We then compute the mean turbulent and thermal energies for all halos in the zoom-in region and compare different definitions of halo averages. Averaging constrained by density and temperature thresholds is favored over averages solely based on virial spheres. We find no clear trend for the turbulent velocity dispersion versus halo mass, but significant correlation and a scaling law with exponent $\alpha\sim 0.5$ between the turbulent velocity dispersion and thermal energy that agrees with a nearly constant turbulent Mach number, similar to more massive objects. We conclude that the self-similar energetics proposed for galaxy clusters extends down to the CGM of individual galaxies., Comment: 12 pages, 11 figures, submitted to Astronomy and Astrophysics

Free-living species vary substantially in the extent of their spatial distributions. However, distributions of parasitic species have not been comprehensively compared in this context. We investigated which factors most influence the geographical extent of mammal parasites. Using the Global Mammal Parasite Database we analysed 17 818 individual geospatial records on 1806 parasite species (encompassing viruses, bacteria, protozoa, arthropods, and helminths) that infect 396 carnivore, ungulate, and primate host species. As a measure of the geographical extent of each parasite species we quantified the number and area of world ecoregions occupied by each. To evaluate the importance of variables influencing the summed area of ecoregions occupied by a parasite species, we used Bayesian network analysis of a subset (n = 866) of the parasites in our database that had at least two host species and complete information on parasite traits. We found that parasites that covered more geographical area had a greater number of host species, higher average phylogenetic relatedness between host species, and more sampling effort. Host and parasite taxonomic groups had weak and indirect effects on parasite ecoregion area; parasite transmission mode had virtually no effect. Mechanistically, a greater number of host species likely increases both the collective abundance and habitat breadth of hosts, providing more opportunities for a parasite to have an expansive range. Furthermore, even though mammals are one of the best studied animal classes, the ecoregion area occupied by their parasites is strongly sensitive to sampling effort, implying mammal parasites are undersampled. Overall, our results support that parasite geographical extent is largely controlled by host characteristics, many of which are subsumed within host taxonomic identity.

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A series of novel nitroheterocyclic phosphoramidates has been prepared, and the cytotoxicity of these compounds has been evaluated in clonogenic assays against B16, wild-type and cyclophosphamide-resistant MCF-7, and HT-29 cells under aerobic conditions and HT-29 cells under hypoxic conditions. All compounds were comparable in toxicity to wild-type and resistant MCF-7 cells and were also selectively toxic to HT-29 cells under hypoxic conditions (selectivity ratios 1.7 to >20). Analogues lacking the nitro group were not cytotoxic. Electron-withdrawing substituents increased cytotoxicity under aerobic conditions and thereby decreased hypoxic selectivity. In contrast, an electron-donating substituent markedly decreased both aerobic and hypoxic cytotoxicity but enhanced hypoxic selectivity. Chemical reduction of the nitro group resulted in rapid expulsion of the cytotoxic phosphoramide mustard. The most potent of these compounds show significant cytotoxicity under both aerobic and hypoxic conditions.

We report the application of nanosecond transient grating spectroscopy to probe the excited state level structure of NO2 near 487.9 nm. Intensity and polarization grating transients were obtained in one-color (DFWM) and two-color (TC-RFWM) configurations. Most grating transients exhibit pronounced beats, arising from coherences among excited state hyperfine levels, which are enhanced in polarization grating experiments. Analysis of these beats yields detailed information on the excited state hyperfine level structure at a resolution 100 times smaller than the bandwidth of the applied laser fields. The grating transients are compared to predictions of the grating decomposition method (GDM) using Fourier transform analysis.

Hydrogen peroxide is a very versatile oxidizing agent, and it is also environmentally compatible considering that the products of its exothermic decomposition are oxygen and water. When kept in a clean temperature-controlled environment, the self-reaction (decomposition) rate is extremely low. However, it is well known that even a small amount of contamination will dramatically increase the reaction rate. This paper describes the use of the fast thermal activity interpreter (FTAI) instrument to examine the chemical reactivity of commercially available 50% hydrogen peroxide at two different temperatures (30 and 40°C) both with and without contamination. The results show that at 30°C a small amount of rust (330 ppm) increases the reaction rate of 50% hydrogen peroxide by a factor of 50. When the temperature is increased to 40°C, the reaction rate is further increased by almost a factor of four. The implication for reactivity management is that at this contamination level most practical vessel sizes would require emergency venting capability. An evaluation was then performed to determine the emergency venting requirement for the safe transportation or storage of the contaminated hydrogen peroxide. It was determined that for quantities of the material less than 5 gallons, conventional breather vents would be sufficient to accommodate the gas evolved. However, for larger quantities, a safety relief device would be needed. For example, for a 400-gallon tote bin at 40°C the required minimum vent area is estimated to be 4.3 in 2 , corresponding to a minimum vent diameter of 2.3 inches.

The ability to predict long-term plant-availability of soil P provides an additional management tool for sustainable agriculture. Our objective is to present a methodology using P fractionation data for predicting long-term plant-availability of soil P. Soil samples were collected (0–30 cm) in 1975, 1985, and 1992 from two continually cropped field trials. Soils were a Norfolk loamy sand and a Davidson clay loam, two Ultisols from North Carolina, USA. Four rates of P were applied from 1975 to 1986, and subsequently discontinued. The relationships between the resin and inorganic NaHCO3 fractions, and between the inorganic NaHCO3 and NaOH fractions, indicated that some level of equilibrium appeared to exist between these three fractions of soil P. Given this equilibrium condition, removal of resin P, as the most plant-available fraction, would subsequently reduce the levels of P in the inorganic NaHCO3 and NaOH fractions. Conversely, adding P as fertilizer would increase P in the resin fraction with a subsequent increase in the inorganic NaHCO3 and NaOH fractions. Although P applied as fertilizer was not completely accounted for in crop removal or net change in soil P, estimated numbers of crops based on our model for predicting available P reflected trends in yields at these two field sites. Sixteen and five crops were estimated for the Norfolk and Davidson soils, respectively. Both corn and soybean yields continued to be high on the Norfolk soil through 1992, while corn yields had declined after 1985 on the Davidson soil. Quantifying the long-term availability of soil P provides some measure of potential return on a capital investment of P fertilization in low-input agriculture.

Sewage sludge contains trace elements. With repeated sludge applications as crop fertilizer, these trace elements may accumulate in the soil to phytotoxic concentrations. My objective was to assess the scientific basis for the current cumulative loading limits for Cu, Ni, and Zn in land-applied sewage sludge. An overview of the USEPA's phytotoxicity risk assessment, the basis for these loading limits, was presented, discussed, and compared in the context of the underlying principles of phytotoxicity thresholds. I concluded that EPA phytotoxicity thresholds in immature plants were arbitrarily selected, and extrapolations to field applications of sewage sludge were not substantiated. Variability in plant accumulation rates and soil sorption capacities of trace elements were not adequately considered in the EPA analysis. Because of the assumptions, simplifications, and extrapolations introduced into the phytotoxicity analysis, the final results, that is, EPA's cumulative loading limits for Cu, Ni, and Zn, are not substantiated by the analysis. The phytotoxicity analysis does not represent an appropriate application of underlying scientific principles. A more appropriate basis for regulating trace element applications in sewage sludge would reflect an understanding of site-specific characteristics, possibly including concentration limits for trace elements in plant tissue, soil, and/or groundwater. Additional research would be required to substantiate EPA's conclusions about the cumulative pollutant loading limits, as derived from EPA's phytotoxicity risk assessment.

Excluding fertilizer P, a finite quantity of soil P exists for plant uptake. To improve our understanding of sinks and sources of long-term plant-available P, soil P fractions to a depth of 30 cm were determined in soils under a continuous cropping system prior to fertilization (1975), after 10 yr of P fertilization (1985), and 6 yr after the last P fertilization (1992). Soil types for two study sites were Norfolk loamy sand (fine-loamy, siliceous, thermic Typic Kandiudult) and Davidson clay loam (clayey, kaolinitic, thermic Rhodic Paleudult). Superphosphate was applied from 1975 to 1986 at rates of 0, 10, 20, and 40 kg P ha -1 yr -1 . Average removal of P, via corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] cropping, was between 10 and 20 kg P ha -1 yr -1 from 1975 to 1992. Resin-extractable soil P increased in the Norfolk soil with annual P applications that were in excess of crop removal and decreased with annual P applications that were less than crop P removal. Resin-extractable soil P decreased to below 3 mg P kg -1 in the Davidson soil regardless of P application or removal rate. Inorganic soil P extracted with NaHCO 3 and NaOH increased with excess P additions and decreased with deficient P additions for both soils. Organic soil P in the Norfolk soil extracted with NaOH represented a P sink at the 40 kg P ha -1 yr -1 treatment in 1985, but subsequently mineralized by 1992. In both soils, inorganic P extracted in the resin, NaHCO 3 , and NaOH fractions, and organic P in the NaOH fraction of the Norfolk soil, represented the biologically dynamic P.

A series of novel nitrobenzyltetrakis(chloroethyl)phosphorodiamidates has been prepared, and its cytotoxicity has been evaluated against HT-29 cells under aerobic and hypoxic conditions and against murine bone marrow progenitor cells under aerobic conditions. All compounds were selectively toxic to HT-29 cells under hypoxic conditions, and the selectivity ratios varied from 1.6 to > 90. Analogs lacking either the nitro group or the tetrakis(chloroethyl) moiety were not cytotoxic, confirming that the presence of both nitro and incipient alkylating groups are essential for activity. Surprisingly, some analogs were far more toxic to bone marrow progenitors than to HT-29 cells under aerobic conditions, suggesting that other activation mechanisms must exist in these hematopoietic cells. Cytotoxicity increased with increasing depth in the HT-29 spheroid model, consistent with the preferential hypoxic toxicity of these compounds. Alkaline elution experiments showed a greater number of DNA interstrand cross-links under hypoxic compared to aerobic conditions. The extent of cross-linking in hypoxic cells was essentially identical to that produced by an equitoxic dose of melphalan, suggesting that the cytotoxicity of these compounds results from phosphorodiamidate release and alkylation of DNA.

Two methods of coupling integrated optical waveguides to photodetectors are investigated. As waveguides, SiON layers were deposited by low-pressure chemical vapor deposition on a thick isolation layer of thermally grown SiO(2) on silicon substrates. Lateral p-i-n diode photodetectors were fabricated by standard processing in the silicon substrates. Structures for end-fire and leaky-wave coupling were fabricated. Coupling efficiencies of up to 84% for end-fire and 88% for leaky-wave coupling were obtained. The fabrication steps are described, and the resulting optoelectrical behavior is discussed.

Decreasing concentrations of extractable Mg in soils of peanut (Arachis hypogaea L.) production regions of North Carolina have resulted in increased Mg fertilizer recommendations. There is little soil or plant criteria, however, on which to base Mg deficiency. The objective of this study was to determine the yield and Mg status of peanuts relative to the level of soil Mg. Five counties were surveyed for leaf and soil data in 1989–90. Similar data were available from nine counties in 1970–72. A field experiment was also conducted in 1989–90 in an on-going lime and Mg study. Although the 1990 survey data suggested that phosphogypsum usage during the last decade may be reducing Mg levels in the surface soil, leaf Mg was almost invariably above 2.0 g kg-1 for both surveys, reflecting adequate amounts of soil Mg according to current plant analysis standards. In the field study, prior lime and Mg treatments resulted in soil Mg ranging from 0.02 to 0.25 cmolc L-1, but there was no yield response that could be related directly to Mg. Leaf Mg was positively correlated to surface soil Mg, and inclusion of subsoil Mg slightly improved this relationship. The data from these studies indicated that sufficient leaf Mg (above 2.0 g kg-1) was attained when surface soil Mg was as low as 0.06 cmolc L-1 or as low as 3 percent of the CEC. We feel these estimates of the soil Mg critical level for peanut production are high, as there was not a Mg deficiency with leaf Mg as low as 1.5 g kg-1 in the field study.

Consistent spatial–temporal yield patterns should help determine spatial production potential. Our objective was to evaluate methods for using yield monitor data to develop spatial yield goal maps. Three to seven years of yield monitor data were analyzed for five sprinkler–irrigated cornfields in central and western Kansas. Yield data were block–averaged to 55 m square cells, normalized based on the mean yield, and then used to develop spatial yield goals for subsequent years using six different methods. One method used a uniform yield goal, two methods combined normalized yield monitor data with a uniform yield goal (transitional), and three methods used only normalized yield monitor data from previous years. Methods were evaluated based on their ability to predict the spatial yield pattern of the subsequent year better than the uniform method. Yield monitor data were also segregated based on the temporal CV of each field during the time of the study, and the six methods were evaluated only on the data that were deemed temporally stable. The result of incorporating yield monitor data into yield goals was inconsistent across sites and years. For one site, the two transitional and three yield monitor methods were significantly better predictors of normalized yield. On another field, the uniform method was a better predictor of normalized yield than the yield monitor methods in three of six years, while the yield monitor methods were better than the uniform method in another year. On a third field, the yield monitor method predicted normalized yield better than the uniform method in one of four years with no difference in the other three years. In general, when the correlation coefficient between two years of yield monitor data exceeded 0.70, the methods that incorporated yield monitor data into the yield goal were better predictors of normalized yield than the uniform method. Evaluating these methods using only data from cells where the temporal CV was less than the average temporal CV for the field did not improve the results sufficiently to warrant widespread use of this practice.

Computing three-dimensional structures from sparse experimental constraints requires method for combining heterogeneous sources of information, such as distances, angles, and measures of total volume, shape, and surface. For some types of information, such as distances between atoms, numerous methods are available for computing structures that satisfy the provided constraints. It is more difficult, however, to use information about the degree to which an atom is on the surface or buried as a useful constraint during structure computations. Surface measures have been used as accept/reject criteria for previously computed structures, but this is not an efficient strategy. In this paper, we investigate the efficacy of applying a surface measure in the computation of molecular structure, using a method of probabilistic least square computations which facilitates the introduction of multiple, noisy, heterogeneous data sources. For this purpose, we introduce a simple purely geometrical measure of surface proximity called maximal conic view (MCV). MCV is efficiently computable and differentiable, and is hence well suited to driving a structural optimization method based, in part, on surface data. As an initial validation, we show that MCV correlates well with known measures for total exposed surface area. We use this measure in our experiments to show that information about surface proximity (derived from theory or experiment, for example) can be added to a set of distance measurements to increase significantly the quality of the computed structure. In particular, when 30 to 50 percent of all possible short-range distances are provided, the addition of surface information improves the quality of the computed structure (as measured by RMS fit) by as much as 80 percent. Our results demonstrate that knowledge of which atoms are on the surface and which are buried can be used as a powerful constraint in estimating molecular structure.

We use an information theoretical framework to estimate the probability of the score of gapped alignments. With appropriate scaling, the score of a global (and with some adjustments also the score of a local) alignment of two sequences can be viewed as the difference in the number of bits needed to transmit the two sequences T1 and T2 under two different encoding schemes C1 and C2. C1 is an idealized scheme, assumed to achieve an optimal encoding with respect to a distribution p, and the assumption that T1 and T2 are independent. C2 is an alternate scheme, that will transmit T1 and T2 while taking advantage of the optimal alignment between the two. That is under C1, the strings T1 and T2 (with respective probabilities p(T1) and p(T2)), are assumed to be encoded using C1(T1, T2) = log [formula: see text] bits. By slightly modifying a known Theorem we show that the probability (under p) that two independent sequences T1, T2 can be transmitted with an alternate encoding scheme (C2) with no more than C1(T1, T2)-r bits is bounded by 2-r. We then show how to use this bound to derive upper bounds for the probability of gapped alignment scores between two sequences.

In this paper we present a formalism for the formation of self consistent, hierarchical, “Low-Level” groupings of pairs of straight line segments from which all higher level groupings may be derived. Additionally, each low-level grouping is associated with a “Quality” factor, based on evidential reasoning, which reflects how much the groupings differ from mathematically perfect ones. This formalism has been incorporated into algorithms within the “LPEG” software package produced at the University of Surrey. LPEG was developed as part of the Vision As Process [Crowley et al., 1989] project. We present results of the application of these algorithms to sets of line segments extracted from a test image.

A psychiatric unit that is characterized by rapid staff and patient turnover was studied longitudinally on four occasions at 6-week intervals, using measures of ward atmosphere, ward activities, perception of patients, and population characteristics. Although the ward did show a great deal of change demographically, perceptions of it were highly stable for patient and staff groups. It was further shown that, in addition to stable perceptions of specific activities or aspects of the milieu, there were also broader underlying perceptual dimensions that were consistent across time. Stable staff-versus-patient and intra-staff differences in perceptions were also found. The results are discussed in terms of the factors that might contribute to the maintenance of such a stable environment, and in terms of the importance of attending to individual variations in perceptions of ward atmosphere.

In this note we show how both known and new sufficient conditions for reachability in boundary control for the heat equation can easily be derived from null controllability. A characterisation of reachable states remains elusive.

We present coloring algorithms for several strong coloring problems and analyze their performance in spaces of random hypergraphs. In these spaces the number of colors used by our algorithms is almost surely within a small constant factor (less than 4) of the strong chromatic number of the hypergraph.

A method is presented for using an adiabatic reactor to study the kinetics of reactions of gases on solid catalysts. The method is based on measurement of the steady state axial profile of temperature or composition in a specially designed adiabatic packed bed reactor. Reaction rates are calculated from these measured profiles by graphical differentitation. The method is applicable for multireaction systems and for any type of kinetic behavior. The method was demonstrated by an experimental study of cumene cracking an silica-alumina catalyst at 420° to 480°C. The measured reaction rates are in satisfactory agreement with results obtained by other investigators who used isothermal reactors. Areas of application of the adiabatic method are suggested.

Studied the interactive effects of examiner, instructional set, field dependence, and extraversion on the reactions of 81 males and 39 females to five Holtzman Inkblot Technique factor scores. Half of the Ss were told that the HIT was a measure of mental health and half that it was experimental in nature, which produced two instructional sets. Field dependence was measured with the Embedded Figures Test and extraversion by the Eysenck Personality Inventory. Subjective anxiety was tapped via the State-Trait Anxiety Inventory. Results revealed no differences among five examiners. However, three of the five HIT factors and the STAI were affected significantly by the instructional set. The effects, while significant, were not massive. Field dependence interacted with instructional set; field dependent Ss reacted with generally more changes in scores than did field independent S. Unlike field dependence, extraversion appeared unrelated to instructional set effects. The results are discussed in terms of how the factor scores interacted with the field dependence and instructional set in psychologically meaningful ways.

We consider two hashing models for storing a set S ⊂ {0, 1, 2, …, m - 1} in a table T of size n.The first model uses universal hashing for a partially loaded table. A set of hash functions is universal if, for any the input set, a randomly selected function has an efficient expected performance. Universal hash functions originate in [CW79], where they were used for open hashing using chaining. [CW79] poses as an open question whether comparable results can be achieved for any closed hashing schemes.The second model is perfect hashing for a full table. In preprocessing the input set is used to determine a hash function that achieves some desired performance criteria. This model was used among others in [ME82] and [FKS84].In both models a key problem is to construct a “small” set of functions, which will permit a short description (program) for each function in the set.We show, for the first time, that universal hashing can be successfully used for closed hashing and in particular for double hashing. Specifically, the set of congruential polynomials of O(log n) degree is universal for double hashing if the table load is below .75; the program size (or number of random bits generated by the algorithm) is O(log log m + log2n).For perfect hashing, we obtain nearly tight results on the size of oblivious O(1)-probe hash functions: Oblivious k-probe hash functions require O(n/k2e-k + log log m) bits of description.A probabilistic construction is presented, which shows that oblivious k-probe hash functions, can be specified in O(ne-k + log log m) bits, which nearly matches the above lower bound.We give a variation of an O(1) time 1-probe (perfect) hash function that can be specified in O(n + log log m) bits, which is tight to within a constant factor of the lower bound.In view of the adaptive schemes presented in [FNSS88], these bounds establish a significant gap between oblivious and non-oblivious O(1)-probe search.

Studied the relationship of diagnosis, age, length of hospitalization, and various measures of perceived level of psychopathology, perceived appropriateness of hospitalization, and sociometric choice among 39 adolescent psychiatric inpatients. Factor analysis revealed two factors, one that was apparently a measure of perceived level of psychopathology and another that was apparently a measure of sociometric choice. Perceptions of an individual's level of psychopathology appear to be shared across staff and patient boundaries. Appropriateness of hospitalization had a strong positive relationship to perceived level of psychopathology and a weak negative relationship to sociometric standing. The relative lack of relationship between sociometric standing and perceived level of psychopathology is discussed in light of past research and methodological design issues.

As community mental health continues to grow in credibility, it has expanded, not only into new areas of treatment (e.g., child abuse), but also into new geographical areas, such as rural Canada. However, transplantation of urban-based community mental health models into the rural community poses major problems. To illustrate such problems as well as possible solutions, this paper describes a day-care program in a non-urban area, the overall settings of the program, a description of its structure and the issues facing it, as well as some of the ways we have dealt with them. We then discuss some recent changes we made in the program and how we evaluated these, to illustrate how such a program can institute an ongoing program evaluation. Finally, some data on the outcome of the program is presented.

Counts were made of the coliform bacilli and psychrophilic organisms in the intestinal contents of arctic ground squirrels while the animals were in the active state and again following periods of hibernation. Total viable aerobic cell counts were also obtained. Data are presented which indicate that there was a significant increase in the number of psychrophiles and a simultaneous decrease in the number of coliform bacilli during hibernation. No changes were found in the total cell counts which could be associated with hibernation.