cssi/SciSciGPT-SciSciNet huggingface dataset:
Morphology and Flow in Streams

Streams are characterized by a continual downstream movement of water, dissolved substances, and suspended particles. These components are derived primarily from the drainage basin or watershed, which is the total land area draining into a given stream channel. Thus the hydrological, chemical, and biological characteristics of a stream reflect the climate, geology, and vegetational cover of the drainage basin [cf., Beaumont (1975), Likens and Bormann (1995), Hynes (1970), Oglesby et al. (1972) and Whitton (1975)]. Water from rain or snow, falling on hilly or mountainous terrain, actually follows diverse routes in moving downhill (Fig. 5.1). Precipitation first may be intercepted by vegetation, then by litter on the surface of the ground. When water is added to the surface of a soil more rapidly than it can soak in (i.e., the infiltration capacity is exceeded) it will run off pverland. Normally, most of the water from precipitation infiltrates into the soil. Soils have variable capacity to store water depending oh depth, structure, composition, and other faqtors. Before stream flow can occur, this storage capacity must be exceeded. Storage capacity jcontinually is made available by evaporation and transpiration (evapotranspiration). Until recently, limnologists have ignored, for the most part, the importance of hydrologic flow paths in regulating the metabolism and biogeochemistry of streams and lakes, as well as their role in the historical generation and accumulation of lake sediments [see Likens (1984)].
Formation of chloroplast membranes in Chlamydomonas reinhardi y-1. Effects of inhibitors of protein synthesis.

Abstract During normal greening of the y-1 mutant of Chlamydomonas reinhardi, photoreductive activities with 2,6-dichloroindophenol (DCI), an assay for Photosystem II, and with methyl red (ascorbate and DCI as electron donors), an assay for Photosystem I, increased in parallel with chlorophyll. Disc membranes formed approximately in parallel with chlorophyll synthesis and fused to form grana. In the presence of 20 µg of chloramphenicol (CAP) per ml, the cells produced chlorophyll and membranes at 90% of the rate of control cells, but photoreductive activities were drastically reduced. Photoreduction of DCI and of methyl red in CAP-treated cells increased at rates only 35% and 50%, respectively, of those in control cells. Also, in CAP-treated cells the discs rarely fused to form grana. Inhibition of these activities was reversible upon removal of CAP. Chlorophyll synthesis and disc formation in cells in the presence of cycloheximide (CHI) at 1 µg per ml occurred at about one-half of the rate of control cells, but photoreductive activity with DCI and disc fusion into grana was the same as in controls on a chlorophyll basis. At concentrations of CHI above 5 µg per ml, chlorophyll synthesis was completely inhibited. The incorporation of 14C-leucine into total protein by whole cells was inhibited maximally 30 to 50% by CAP and maximally 40 to 50% by CHI; the effects of the drugs were additive. The membranes formed in the presence of CAP could be repaired by transferring the cells to a medium containing CHI (10 µg per ml). During 2 hours of subsequent incubation in light, the existing membranes gained activity until, on a chlorophyll basis, they were at least as active as the membranes formed in control cells. These results indicate that products of both the cytoplasmic and the chloroplastic protein-synthesizing systems are required for disc membrane production in the chloroplast of this alga.
Synthesis of anatase TiO2 nanocrystals with exposed {001} facets.

This paper reports a facile synthesis of anatase TiO2 nanocrystals with exposed, chemically active {001} facets. The nanocrystals were prepared by digesting electrospun nanofibers consisting of amorphous TiO2 and poly(vinyl pyrrolidone) with an aqueous acetic acid solution (pH = 1.6), followed by hydrothermal treatment at 150 °C for 20 h. The as-obtained nanocrystals exhibited a truncated tetragonal bipyramidal shape with 9.6% of the surface being enclosed by {001} facets. The use of electrospinning is critical to the success of this synthesis as it allows for the generation of very small particles of amorphous TiO2 to facilitate hydrothermal crystallization, an Ostwald ripening process. The morphology of the nanocrystals had a strong dependence on the pH value of the solution used for hydrothermal treatment. Low pH values tended to eliminate the {001} facets by forming sharp corners while high pH values favored the formation of a rodlike morphology through an oriented attachment mechanism. When acetic ac...
Emphasizing formal analysis in a software engineering curriculum

The integration of formal method application throughout a six course software engineering curriculum is outlined. Formal analysis skills were included in order to increase the complex program solving skills of the student. The five instruction-oriented courses presented highlight how formal analysis was introduced in and applied to the corresponding subject material. The materials presented, along with an accounting of the experiment, provide a basis for other academicians to teach formal analysis at their own institutions.
Evaluation of a BSW Research Experience: Improving Student Research Competency

This article examines the experience of 24 BSW students in a faculty-mentored undergraduate research experience (URE) over the course of 1 academic year. In particular, we sought to better understand students’ self-perceived sense of competency across 15 specific research skills. In addition, we examined the URE’s impact on students’ knowledge about and attitudes toward research, as well as anxiety levels about research. A cross-sectional pre- and posttest design utilized both quantitative (survey) and qualitative (focus group) methodologies. All of the students’ ratings of their 15 research skills improved over time; 3 were statistically significant. Students demonstrated the most gain in evidence-based practice, ability to use statistical software, and data entry and analysis. Both knowledge about and attitude toward research improved significantly. Anxiety levels were surprisingly low. The importance of faculty mentoring is discussed, and suggestions for future research are provided.
Design of network topology in an adversarial environment

We study the strategic interaction between a network manager whose goal is to choose (as communication infrastructure) a spanning tree of a network given as an undirected graph, and an attacker who is capable of attacking a link in the network. We model their interaction as a zero-sum game and discuss a particular set of Nash equilibria. More specifically, we show that there always exists a Nash equilibrium under which the attacker targets a critical set of links. A set of links is called critical if it has maximum vulnerability, and the vulnerability of a set of links is defined as the minimum fraction of links the set has in common with a spanning tree. Using simple examples, we discuss the importance of critical subsets in the design of networks that are aimed to be robust against attackers. Finally, an algorithm is provided, to compute a critical subset of a given graph.
Language model and acoustic model information in probabilistic speech recognition

The authors propose an approach to the estimation of the performance of the language model and the acoustic model in probabilistic speech recognition that tries to take into account the interaction between the two. It consists of a new measure, called speech decoder entropy (SDE), of joint acoustic-context information. Some results are presented for a 20000-word vocabulary recognizer. The authors discuss some limitations of the work and some suggestions for future developments. >
Modeling studies of the upper ocean response to a tropical cyclone

A coupled ocean and boundary layer flux numerical modeling system is used to study the upper ocean response to surface heat and momentum fluxes associated with a major hurricane, namely, Hurricane Dennis (July 2005) in the Gulf of Mexico. A suite of experiments is run using this modeling system, constructed by coupling a Navy Coastal Ocean Model simulation of the Gulf of Mexico to an atmospheric flux model. The modeling system is forced by wind fields produced from satellite scatterometer and atmospheric model wind data, and by numerical weather prediction air temperature data. The experiments are initialized from a data assimilative hindcast model run and then forced by surface fluxes with no assimilation for the time during which Hurricane Dennis impacted the region. Four experiments are run to aid in the analysis: one is forced by heat and momentum fluxes, one by only momentum fluxes, one by only heat fluxes, and one with no surface forcing. An equation describing the change in the upper ocean hurricane heat potential due to the storm is developed. Analysis of the model results show that surface heat fluxes are primarily responsible for widespread reduction (0.5°–1.5°C) of sea surface temperature over the inner West Florida Shelf 100–300 km away from the storm center. Momentum fluxes are responsible for stronger surface cooling (2°C) near the center of the storm. The upper ocean heat loss near the storm center of more than 200 MJ/m2 is primarily due to the vertical flux of thermal energy between the surface layer and deep ocean. Heat loss to the atmosphere during the storm’s passage is approximately 100–150 MJ/m2. The upper ocean cooling is enhanced where the preexisting mixed layer is shallow, e.g., within a cyclonic circulation feature, although the heat flux to the atmosphere in these locations is markedly reduced.
H/sub infinity / optimization with time domain constraints over a finite horizon

An algorithm for computing the solution to H/sub infinity / problems with time domain constraints over a finite horizon is presented. This problem is transformed into a convex finite-dimensional optimization problem. Some of the characteristics of the optimal solution are established, namely, the degree of the optimal solution and its behavior in the special case in which the constraints are not binding, in order to gain further insight into the nature of the optimization problem, including the fact that it is in general nondifferentiable. An example is presented in which the technique provides better time responses with only slight deterioration of the robustness properties as compared with the unconstrained H/sub infinity /-optimal solution. Although all the results were obtained for single input-single output systems, they extend naturally to multivariable systems. >
Seeing Masculine Men, Sexy Women, and Gender Differences: Exposure to Pornography and Cognitive Constructions of Gender

ABSTRACT This article examines the relation between men's exposure to pornography and their beliefs about men and women. Study 1 presents an individual difference measure for assessing exposure to pornography that was then used in six subsequent studies. In Study 2, high exposure scores predicted being male, having a sexual partner, and the reasons for viewing sexual materials. In Studies 3 and 4, high exposure men were more likely than low exposure men to think that most men perform masculine behaviors. In Studies 5 and 6, high exposure men were also more likely lo generate sexual descriptions of women spontaneously. Finally, in Study 7, high exposure men perceived the most gender differences after viewing sexual or sexual/violent music videos; low exposure men perceived the most differences after viewing sexual or romantic ones. These studies suggest that exposure to pornography is related to broad and fundamental ways of understanding men, women, and gender relations.
The effects of local employment opportunities on youths' work and schooling

This study uses individual-level data from the Sample Edited Detail File of the 1990 Decennial Census of the United States to estimate multinomial logit models of young men's and women's enrollment and employment behavior. The models include county-level averages of (1) the earnings opportunities currently available to individuals with similar educational backgrounds and (2) the difference in earnings opportunities associated with additional schooling as explanatory variables. Estimates indicate that young people who have not yet completed high school are relatively insensitive to changes in earnings opportunities. For young people who have completed high school, increases in current earnings opportunities modestly reduce enrollments and increase employment.
The midgestational maternal blood pressure decline is absent in mice lacking expression of the angiotensin II AT2 receptor.

The midgestational maternal blood pressure (BP) decrease is absent in mice treated with an angiotensin II AT2 receptor blocker. We tested the hypotheses that there would be 1) no midgestational decrease in maternal systolic BP (SBP) in AT2-/- mice, and 2) a pattern of increased AT2 and/or decreased AT1a mRNA expression in tissues from normal (wild-type, WT) mice, corresponding with SBP changes. Heart, aorta, placenta and kidney tissue were obtained from WT and AT2-/- mice before pregnancy and on gestational days (Gd) 5-6, 12-13 and 18-19. AT1a and AT2 mRNA expression was quantified. SBP was measured. SBP was significantly decreased in WT Gd12-13 mice, but did not change during pregnancy in AT2-/- mice. In WT mice, aortic AT1a mRNA expression levels were significantly higher at Gd12-13 and Gd18-19 compared with before pregnancy. AT1a kidney and heart mRNA did not change during pregnancy. There were no changes in AT2 mRNA expression. There was no distinct pattern of change in AT1a expression in AT2-/- mice. Placental AT1a and AT2 expression levels increased markedly between Gd12-13 and Gd18-19 in WT mice. We conclude that the AT2 receptor is essential for the midgestational SBP decline in WT mice. There is no consistent relationship between changes in tissue angiotensin II receptor mRNA expression and SBP in WT mice.
Solving the price puzzle with an alternative indicator of monetary policy

We identify the effects of monetary policy shocks on macroeconomic variables in VARs using the Divisia M4 measure of money as the policy indicator variable. We obtain theoretically sensible responses—whether or not a commodity price index is included. Thus, we eliminate the well-known empirical puzzles from the VAR by a novel choice in a policy variable, rather than the usual attachment of an ad hoc variable.
Micronuclei in adult and foetal mice exposed in vivo to heliotrine, urethane, monocrotaline and benzidine.

Abstract The level of clastogenic damage in mice following in vivo adult and transplacental exposure to benzidine, heliotrine, monocrotaline and urethane was compared using the micronucleus (MN) assays of polychromatic erythrocytes (PCE) found in mouse adult bone marrow and foetal liver. Saline was used as a negative control. Swiss-albino mice (gestation 17–19 days) were given a single acute intraperitoneal injection. Animals sacrificed 21 h after 0.75 LD50 of each chemical had significantly increased frequencies f micronucleated PCE in adult and foetal tissues (p
An in vitro model system to evaluate pulmonary macrophage, endothelial cell, and neutrophil interactions.

Pasteurella haemolytica, the cause of fibrinous pleuropneumonia in cattle, produces extensive microvascular endothelial cell (EC) damage. We have developed anin vitro model system to study the inflammatory process of this disease involving the interaction of pulmonary alveolar macrophages (AM), neutrophils (PMN), and EC. Bovine EC are grown to confluency in 24 well tissue culture plates. To mimic the vascular component, 106 PMN are later added to the EC monolayers. Bovine AM are plated onto millicell inserts and placed into the wells containing EC and PMN. The millicell insert serves as a semi-permeable barrier between AM and EC, allowing the exchange of only diffusible material. Preliminary work demonstrates thatP. haemolytica stimulated AM resulted in EC damage presumably due to both soluble lipopolysaccharide and AM secreted products.
Superoxide-dependent redox cycling of citrate-Fe3+: Evidence for a superoxide dismutaselike activity

Abstract Citrate-Fe3+, reportedly a physiological chelate, exhibits superoxide dismutaselike activity, as evidenced by (i) the inhibition of xanthine oxidase-dependent cytochrome c reduction; (ii) the dismutation of xanthine oxidase-generated superoxide to hydrogen peroxide and oxygen, and (iii) the enhanced disproportionation of potassium superoxide. The catalytic activity of citrate-Fe3+ corresponds, on a molar basis, to 0.03% of that of copper- and zinc-containing superoxide dismutase. Although weak, this activity enables citrate-Fe3+ to inhibit superoxide and ADP-Fe3+-dependent peroxidation of extracted microsomal lipids. Also, the dismutase activity of citrate-Fe3+ interferes with its ability to promote lipid peroxidation. It is proposed that chelation of Fe3+ by citrate may represent a protective mechanism against the deleterious consequences of superoxide generation.
Metabolic control in perfused rat heart during fluoroacetate poisoning

Abstract The inhibitory effect of fluoroacetate on the citric acid cycle is due to the synthesis of fluorocitrate, which is a competitive inhibitor of aconitase (Peters, 1957) . Consequently, citrate accumulates in fluoroacetate poisoned tissues. Margreth and Azzone (1964) have recently reported that rat heart homogenates have a large endogenous fluoroacetate insensitive respiration, and on the basis of studies with metabolic inhibitors concluded that it was largely supported by the utilization of glutamate and glycelytically generated DPNH. The present investigation with the isolated perfused rat heart has failed to substantiate this suggestion. In this paper we report data on the mechanical performance of the heart during fluoroacetate poisoning, and metabolic control points have been identified by applying the cross-over theorem of Chance et al (1958) to the glycolytic system and the citric acid cycle.
Growth and change in undercover online child exploitation investigations, 2000-2006.

This paper documents changes in the rates and characteristics of undercover police investigations against child sexual exploiters on the Internet. Telephone interviews were conducted with law enforcement officials about a nationally representative sample of cases ending in arrest for an Internet-related sex crime against a minor in 2000 and 2006. The survey found a 280% increase in arrests of offenders identified in undercover operations between the two time periods. This translates to an increase in estimated numbers of arrests nationwide from 826 to 3137. Federally funded Internet Crimes Against Children Task Forces showed the largest increase in arrests by 988%. The growth in arrests suggests the successful adaptation of new technology and training to improve police effectiveness.
Bubble interaction in low-viscosity liquids

An experimental study investigated how freely rising ellipsoidal bubbles approach each other, make contact and coalesce or breakup. Pulsed planar swarms of 10–20 bubbles with Eotvos numbers from 6.0 to 27.5 were released simultaneously in aqueous solutions of 0–48 wt% sugar with Morton numbers from 3.2 × 10−11 to 3.7 × 10−6. Bubble interaction was recorded by a video camera following the rising bubbles. Essentially, all coalescence and breakup events occurred after, not during, wake-induced collisions by a complex process related to the bubble vortex shedding cycle. This same process was also found in multi-bubble clusters and may account for excess turbulent kinetic energy generation in bubbly flow.
A prefrontal dysfunction model of early-treated phenylketonuria.

A prefrontal dysfunction model of early-treated phenylketonuria (PKU) is discussed. The biochemical perturbations caused by this genetic disorder have been found to result in depleted dopamine, a neurochemical that is critical for prefrontal cortical function. Studies of the neuropsychological sequelae of early-treated PKU in children are reviewed, and it is suggested that findings indicating executive function (EF) impairments are consistent with the prefrontal dysfunction hypothesis. An alternative model of the neuropsychological effects, that of a left-hemisphere dysfunction, is also discussed. Although a substantial amount of research has explored the neuropsychological performance of children with early-treated PKU, the extent to which these EF deficits are maintained into adolescence and adulthood is unclear. The neuropsychological expression of early-treated PKU across development requires further investigation and should provide a window on the general nature of brain development and function.
Strongly singular convolution operators on the heisenberg group

We consider the L2 mapping properties of a model class of strongly singular integral operators on the Heisenberg group Hn; these are convolution operators on Hn whose kernels are too singular at the origin to be of Calderon-Zygmund type. This strong singularity is compensated for by introducing a suitably large oscillation. Our results are obtained by utilizing the group Fourier transform and uniform asymptotic forms for Laguerre functions due to Erdelyi.
Organization of connections of the basal and accessory basal nuclei in the monkey amygdala.

PLEASE NOTE: Expression of Concern (EJN, 12:11, p4153) The present study investigated the intrinsic connections of the basal and accessory basal nuclei of the Macaca fascicularis monkey by means of the anterograde tracers Phaseolus vulgaris-leucoagglutinin (PHA-L) and biotinylated dextran amine (BDA). Analysis of the intranuclear connections of the basal nucleus indicates that there are five modules: dorsal, intermediate, ventral lateral, ventral medial and periamygdaloid sulcal cortex. The dorsal division projects to the intermediate division. Laterally, the intermediate division projects to the ventral lateral division and dorsal parts of the ventral medial division. Ventrally, the ventral lateral division projects to the ventral medial division and periamygdaloid sulcal cortex, which appears to constitute a medial extension of the basal nucleus onto the cortical surface of the amygdala. Medially, the ventral medial division projects to the intermediate and dorsal divisions. Thus, the connections between these modules form functional microcolumns within the nucleus with distinct patterns of information flow that are dorsal to ventral laterally, lateral to medial ventrally, and ventral to dorsal medially. Observations on the intranuclear connections of the accessory basal nucleus suggest that they are organized into two relatively distinct domains: the dorsal division projects to the ventral division and the ventral division projects primarily to the ventromedial division. Projections to other amygdaloid areas originate in select divisions of the basal and accessory basal nuclei, and are topographically distributed. The organization of intrinsic connections of the basal nuclei correlates with specific amygdalo-cortical connections and suggests that extensive convergence of information takes place within the amygdala, which potentially influences activity at both the temporal and parietal pathways and hippocampal fields.
Description and analysis of early faults based on geometry of fault-bed intersections

Abstract The cross-sectional configuration of dip-slip faults in stratified rocks can be characterized in terms of sense of displacement, relative age of faulted strata, polarity, hangingwall ramp/flat type, footwall ramp/flat type, hangingwall younging direction and footwall younging direction. Together, these variables provide a descriptive framework for observations at single outcrops, and a tool for kinematic analysis of deformed early faults. Contractional and extensional faults cutting strata that were flat-lying when faulted can produce only 20 initial fault configurations. Including derivative configurations that result from fault-propagation folding and post-fault deformations, as many as 120 fault configurations might be encountered in early faults. Application of these concepts is demonstrated through analysis of a major premetamorphic fault in the Acadian Orogen in Maine, which is reinterpreted as a contractional rather than an extensional structure.
Co-ordination complexes of oxovanadium (IV) with substituted pyridine 1-oxides

Abstract Twenty-one complexes of oxovanadium (IV) chloride, bromide, thiocyanate, perchlorate and tetrafluoroborate with various substituted pyridine 1-oxide ligands have been prepared and characterized. The variation in stoicheiometry depended both upon the type of donor molecule (activator or deactivator substitution) and the sources of oxovanadium (IV) ions. Complexes of the type VOL5X2, VOL4X2·H2O, VOL2X2·H2O and VOL2X2 were prepared.
Internet Addiction: A New Clinical Phenomenon and Its Consequences

New research identifies online users who became hooked on chat rooms, interactive games, and even eBay only to see their lives become increasingly unmanageable because of the Internet. Prior resear...
SAT State Comparisons: A Response to Marchant and Paulson (2001)

The College Board discourages ranking states and has made a change in policy in the presentation of data. Although it is not invalid nor inappropriate to report test scores by state, invalid inferences may be drawn from these scores. Further research based on analytically appropriate methods is recommended.
Super resolution image reconstruction using averaged image and regularized deconvolution

Super resolution (SR) image reconstruction is used to obtain a high resolution (HR) image from multiple low resolution (LR) images. In this paper, we propose a new method to solve the SR reconstruction problem. The LR images are modeled as downsampled images of the original scene shifted by sub-pixel distances. In addition, we model the downsampling process as averaging light intensity on the corresponding pixel area. Based on this downsampling model, the average of multiple LR images with appropriate registration can be thought of as a blurred version of the HR image. After the point spread function (PSF) for this blur is identified, the HR image is obtained by regularized deconvolution method. The regularization factor can be determined by line search of a cost function. Two distinct cases are considered: (1) only translational motion among LR images is assumed, (2) both translational and rotational motions among LR images are considered. For the second case, the rigid body group representation is used.
Animal models of chronic pain: scientific and ethical issues.

Chronic pain is a major health care problem throughout the world. Available data indicate that acute pain syndromes cont~bute significantly to health care costs but that chronic or recurrent pain produces an even greater economic burden in addition to social and psychological problems [8,19]. As the medical and scientific community has become aware that chronic pain is different from acute pain and has its own high economic and social costs, there has developed increased interest in research focused on the etiology and treatment of chronic pain. In this paper, we will focus on the implications this interest in chronic pain has for the conduct of basic research in animals. The importance and nature of the clinical problem have raised questions about the need to develop animal models to study the pathophysiological processes that may be unique to chronic pain. However, the development and use of models in which animals are exposed to persistent painful stimuli present serious and difficult ethical problems that require continuing discussion among scientists [2,3,6]. Some definitions are in order before discussing these issues. We accept the definition of the Taxonomy Committee of the IASP: (pain is) ‘an unpleasant sensory and emotional experience as-
The regeneration and division of mouse L-cell karyoplasts

Abstract A technique for efficient cytochalasin-induced enucleation was used to prepare "karyoplasts" — nuclei surrounded by a thin shell of cytoplasm and an outer cell membrane. Methods for estimating the quantity of cytoplasm remaining in karyoplasts indicated that they contained less than 10% of the amount found in whole cells. Procedures for separating karyoplasts from contaminating cytoplasmic fragments and whole cells are also described. Freshly prepared L-cell karyoplasts were unable to adhere to and spread upon a surface. However, after incubation for several days, about 30% of the karyoplasts regained these abilities to some degree. A portion of the regenerating karyoplasts were then observed to divide. These events were confirmed and recorded by time-lapse cinematography. In addition, by culturing karyoplasts under appropriate conditions, clones were isolated.
Uranyl acetate as a direct inhibitor of DNA-binding proteins

Zinc finger proteins, one of the largest families of DNA-binding proteins in higher eukaryotes, are so named because they require zinc ions for appropriate structure and function. Dysregulation of zinc finger-containing DNA transcription and repair proteins has been proposed as a potential mechanism for the toxic effects of some metal ions. Uranium metal has been reported to be both a cytotoxic and a genotoxic agent. We hypothesized that these toxic effects of uranium might be due to its ability to directly disrupt zinc finger activity. To test this hypothesis, two purified zinc finger proteins, Aart and Sp1, were analyzed by electrophoretic mobility shift in the presence of uranyl acetate. Inhibition of binding was apparent at 10 microM uranyl acetate, while no inhibition was observed with up to 2000 microM the cytotoxic metalloid sodium arsenite. Preincubation of the DNA with uranyl acetate did not inhibit zinc finger protein binding, suggesting that the inhibition was due to direct uranyl interaction with the protein. Surprisingly, uranyl acetate inhibited two nonzinc finger DNA-binding proteins, AP1 and NF-kappaB, to a similar extent, and zinc finger inhibition was reduced in the presence of bovine serum albumin. These results suggest that uranium can directly inhibit the function of DNA-binding proteins, most likely via a nonspecific protein interaction.
Spectroscopic characterization of silicalite-1 and titanium silicalite-1

Abstract Titanium silicalite samples were prepared by two different procedures. A titanium-free sample (silicalite-1) was also prepared. The samples were characterized by XRD, SEM, skeletal ET-FIR and FT-Raman, UV-vis FT-IR of hydroxy- groups and of adsorbed ammonia. The skeletal spectra have been analyzed on the basis of a general interpretation of the vibrational structure of tetrehedra-based silica polymorphs. This lead to a partial modification of the traditional assignments of the skeletal vibrations of zeolites. Framework Ti is found to be responsible for a band near 960 cm −1 , in both IR and Raman spectra, and for a shoulder near 510 cm −1 in the IR spectra, as well as for other weak perturbations of the silicalite spectra. The two main features have been assigned to the asymmetric stretching and to the rocking modes of Si-O-Ti bridges. Framework Ti is found to act as a Lewis acid center, being able to coordinate ammonia from gas-phase. Extraframework Ti is observed in the form of anatase in samples prepared with the procedure 1 only with Ti content above 2%, while TiO 2 is found in all samples prepared with the procedure 2. Both series of samples are active catalysts of phenol hydroxylation by H 2 O 2 .
Antidepressant-like effect of Δ9-tetrahydrocannabinol and other cannabinoids isolated from Cannabis sativa L.

The antidepressant action of cannabis as well as the interaction between antidepressants and the endocannabinoid system has been reported. This study was conducted to assess the antidepressant-like activity of Δ9-THC and other cannabinoids. Cannabinoids were initially evaluated in the mouse tetrad assay to determine doses that do not induce hypothermia or catalepsy. The automated mouse forced swim (FST) and tail suspension (TST) tests were used to determine antidepressant action. At doses lacking hypothermic and cataleptic effects (1.25, 2.5, and 5 mg/kg, i.p.), both Δ9-THC and Δ8-THC showed a U-shaped dose response with only Δ9-THC showing significant antidepressant-like effects at 2.5 mg/kg (p < 0.05) in the FST. The cannabinoids cannabigerol (CBG) and cannabinol (CBN) did not produce antidepressant-like actions up to 80 mg/kg in the mouse FST, while cannabichromene (CBC) and cannabidiol (CBD) exhibited significant effect at 20 and 200 mg/kg, respectively (p < 0.01). The antidepressant-like action of Δ9-THC and CBC was further confirmed in the TST. Δ9 -THC exhibited the same U-shaped dose response with significant antidepressant-like action at 2.5 mg/kg (p < 0.05) while CBC resulted in a significant dose dependent decrease in immobility at 40 and 80 mg/kg doses (p < 0.01). Results of this study show that Δ9-THC and other cannabinoids exert antidepressant-like actions, and thus may contribute to the overall mood-elevating properties of cannabis.
The potencies of synthetic analogues of saxitoxin and the absolute stereoselectivity of decarbamoyl saxitoxin

The potencies of synthetic saxitoxin (+/- STX) and six of its synthetic analogues, including the enantioselectively synthesized unnatural (-)enantiomer of decarbamoyl saxitoxin (dcSTX), were measured and compared to those of natural saxitoxin [(+)STX]. The analogues, all of which were racemic (+/-) mixtures except for dcSTX, varied in the substituents at the C6 position, the carbamoyl 'moeity', and the C12 position, the hydrated ketone. The ability of the toxins to inhibit the compound action potential (AP) and to displace radiolabeled natural saxitoxin (3H-STX) from nerve membranes at equilibrium were both used as potency assays. Biological activity of both (+)- and (-)dcSTX was analyzed by the kinetics of block of single Na+ channels reconstituted in planar lipid bilayer membranes, where it was demonstrated that only (+)dcSTX had biological activity. The potency of STX analogues fell markedly as the substituent at the C6 position became smaller; Ki values from the binding competition assay (at 4 degrees C) are: (+/-)6-methanolic-STX, 5 x 10(-10) M; (+/-)6-methyl-STX, 1 x 10(-6) M; (+/-)6-dihydro-STX, 3.5 x 10(-5) M. Replacement of the ketone at the C12 position by a methylene group was accomplished in two derivatives, although both also had substituents at the C6 position. The compound (+/-)6-methyl-12-deoxy-STX was about 0.03 as potent as (+/-)6-methyl-STX and only 10(-5) as potent as racemic (+/-)STX. In synthetic compounds where the benzyloxymethyl (-CH2OCH2C6H5) substituent occurred at the C6 position, the C12-methylene derivative still displayed some binding activity (Ki = 6 x 10(-4) M). However, when the same C6 derivatized compounds also contained a 6-membered heterocyclic group (-C3H8S2-) conjugated to carbon 12, the measured binding affinity was even further decreased (Ki = 2 x 10(-3) M). The findings show that substitutions on the carbon 6 position of STX have stronger effects on STX potency than previously believed, and that the toxin may form a hydrogen bond with the sodium channel at this site. Furthermore, the total removal of oxygen from the C12 position does not completely abolish the binding activity of the molecule.
Peroxisome Proliferator-Activated Receptor and Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is the leading cause of new blindness in the western world and is becoming more of a socio-medical problem as the proportion of the aged population increases. There are multiple efforts underway to better understand this disease process. AMD involves the abnormal retinal pigment epithelium (RPE), drusen formation, photoreceptor atrophy, and choroidal neovascularization. Peroxisome proliferator-activated receptors (PPARs) play an important role in lipid degeneration, immune regulation, regulation of reactive oxygen species (ROSs), as well as regulation of vascular endothelial growth factor (VEGF), matrix metalloproteinase-9 (MMP-9), and docosahexaenoic acid (DHA). These molecules have all been implicated in the pathogenesis of AMD. In addition, PPAR gamma is expressed in RPE, an essential cell in photoreceptor regeneration and vision maintenance. This review summarizes the interactions between PPAR, AMD-related molecules, and AMD-related disease processes.
Chk1 signaling pathways that mediated G2M checkpoint in relation to the cellular resistance to the novel topoisomerase I poison BNP1350

Abstract A novel karenitecin, BNP1350, is a topoisomerase I-targeting anticancer agent with significant antitumor activity in vitro and in vivo. A BNP1350-resistant human head and neck carcinoma A253 cell line, denoted A253/BNPR, was developed. The A253/BNPR cell line was approximately 9-fold resistant to BNP1350 and 4-fold cross-resistant to another topoisomerase I inhibitor SN-38, the active metabolite of irinotecan. After drug treatment with equimolar concentrations of BNP1350 (0.7 μM) for 2 h, activation of the DNA double-strand break repair protein complexes was similar in the two cell lines, suggesting that DNA dsb repair is not attributable to resistance to BNP1350 in the A253/BNPR cells. Cell cycle analysis indicates that the A253 cell line accumulated primarily in S phase, but G2 phase accumulation was observed in the A253/BNPR cell line at 48 h after drug removal. Elevated chk1 phosphorylation at Ser345 following DNA damage induced by BNP1350 was accompanied by G2 accumulation in the A253/BNPR cell line, while exposure to equimolar concentrations of BNP1350 (0.7 μM) induced S-phase arrest and no increased phosphorylation of chk1 at Ser345 in the A253 cell line. Under the same conditions, increased chk1 activity was observed in the A253/BNPR cell line, but not in the A253 cell line. Moreover, stimulated binding of 14-3-3 proteins to chk1 was observed in BNP1350-treated A253/BNPR cells. To confirm relationship between chk1 expression/phosphorylation and drug resistance to topo I poisons, we examined the effects of chk1 or chk2 antisense oligonucleotides on the cellular growth inhibition. Chk1 antisense oligonucleotide can sensitize the A253/BNPR cells to killing by topo I inhibitor BNP1350, but no significant sensitization of BNP1350-induced growth inhibition was observed in the drug-sensitive cell line. Chk2 antisense oligonucleotide has only a small sensitization effect on BNP1350-induced growth inhibition in both cell lines. The data indicate that the chk1 signaling pathways that mediate cell cycle checkpoint are associated with cellular resistance to BNP1350 in the A253/BNPR cell line.
Low Temperature Magnetic Susceptibility of Cu(II) Porphine

ONE of the basic problems in very low temperature physics is the choice of paramagnetic materials for adiabatic demagnetization and thermometry. To be suitable for magnetic cooling the sample must remain paramagnetic down to the lowest temperatures of interest. For thermometric use the susceptibility should also exhibit Curie law behaviour so that extrapolation to lower temperatures is meaningful. To satisfy both of these conditions an inorganic salt is normally used in which the density of magnetic ions is very low by virtue of large numbers of waters of hydration. Cerium magnesium nitrate [CeMg3(NO3)12.24H2O] is the most commonly used salt.
Probing the Catalytic Triad of an Archaeal RNA Splicing Endonuclease

Among the four known mechanisms of intron removal, three are reputedly catalyzed by RNA molecules. In the fourth mechanism, a protein endonuclease removes introns from nuclear tRNA and all archaeal RNAs. Three strictly conserved residues of the splicing endonuclease, a histidine, a lysine, and a tyrosine, were predicted to catalyze the intron cleavage reaction in a manner similar to that of the catalytic triad of ribonuclease A. Single-turnover kinetic parameters were obtained for the wild-type enzyme and two triad mutants. Mutation of histidine to alanine produced an at least approximately 28-fold reduction; mutation of tyrosine to phenylalanine produced an at least approximately 7-fold reduction in activity, while a histidine and tyrosine double mutation abolished cleavage. The single mutation of lysine to glutamic acid abolished RNA cleavage activity in the absence of a divalent metal but maintained a substantial level of activity in the presence of specific divalent metals. These data support important functional roles already proposed for the catalytic triad and suggest an intriguing hypothesis in which the splicing endonuclease is an intermediate in the transition from the RNA to the RNP world.
Modeling injection well performance during deep-well injection of liquid wastes

Abstract Deep-well injection of municipal and industrial wastes, and liquid hazardous wastes is an important waste disposal practice worldwide. Performance of injection wells during the deep-well injection of liquid wastes and waste waters is critically dependent upon the physico-chemical properties of the waste, the operational parameters such as injection rates and pressures, as well as the hydrogeologic and geochemical character of the host formation. Development of theories and models that can predict the injection well performance as a function of these parameters is a vital research need. This paper presents the development and application of a well injectivity decline (WID) simulator, that can be used to model injection well performance during deep-well injection. Injectivity decline due to particulates in the injection fluid is modeled for various types of well completions. Results from the simulator are presented with an emphasis on the resulting well plugging and injectivity decline. The significant role played by injected wastewater quality, host formation properties, injection rate and pressure, well completion type, initial damage to the well/formation and the presence of gravel packs around the wellbore is discussed. The results quantitatively show that under typical injection conditions a high total suspended solids (TSS) concentration in the waste stream, low injection rate, low injection pressures, formation heterogeneity (layering), low porosity and permeability of the formation all contribute to a rapid decline in injection well performance. The simulator provides a tool for predicting well performance during waste injection as a function of the waste, formation and operational characteristics. Such simulations can be valuable during planning and operating injection wells to achieve and sustain satisfactory well performance.
Cost-effectiveness of concurrent supercomputers

This article introduces a mathematical function that describes the latent concurrency inherent in an arbitrary program with given initial conditions. The concurrency function is used to derive asymptotic estimates for speedup, including Amdahl's Law. It provides a new method for analyzing cost-effectiveness of the processor-memory-communications constituents of a computing system for applications where system cost and execution time are mutually elastic variables. The costs of programming and input/output are not taken into account in the present study. The methods are applied to study the relative advantages of serial versus concurrent processing; the relationship of the memory/processor ratio to cost-effectiveness; the conditions that determine the relative advantages of SIMD and MIMD control structures; the effects of various interprocessor communication strategies; and cost-effectiveness implications of the choice of data path width.
Security, Dignity, Caring Relationships, and Meaningful Work: Needs Motivating Participation in a Job-Training Program

Researchers asked 17 participants in a job-training program to describe their personal struggles following an economic restructuring. Examined through a critical theoretical lens, findings indicate that the learners enrolled in the program to reclaim security, dignity, meaningful work, and caring relationships. Program planners at community colleges are therefore urged to employ democratic program planning models, ask learners about their educational needs as they see them, and listen compassionately to their responses.
Mesoscale Eddy–Internal Wave Coupling. Part I: Symmetry, Wave Capture, and Results from the Mid-Ocean Dynamics Experiment

Abstract Vertical profiles of horizontal velocity obtained during the Mid-Ocean Dynamics Experiment (MODE) provided the first published estimates of the high vertical wavenumber structure of horizontal velocity. The data were interpreted as being representative of the background internal wave field, and thus, despite some evidence of excess downward energy propagation associated with coherent near-inertial features that was interpreted in terms of atmospheric generation, these data provided the basis for a revision to the Garrett and Munk spectral model. These data are reinterpreted through the lens of 30 years of research. Rather than representing the background wave field, atmospheric generation, or even near-inertial wave trapping, the coherent high wavenumber features are characteristic of internal wave capture in a mesoscale strain field. Wave capture represents a generalization of critical layer events for flows lacking the spatial symmetry inherent in a parallel shear flow or isolated vortex.
Managing vegetation within U.S. national parks: A policy analysis

The development of U.S. national park vegetation management policies is briefly traced from 1872, when Yellowstone National Park was created, to the present. Ambiguities in legislative policies are described and partially resolved. Alternative vegetation management objectives, consistent with those policies, are evaluated using quantitative data from a giant sequoia-mixed-conifer forest community in Kings Canyon National Park. It is concluded from an analysis of this data that structural maintenance objectives are biologically infeasible in this forest community because the community does not have a fully regulated or steady-state distribution of aggregation types. Since such a steady-state distribution of aggregation types is probably not present in most forest communities, the Park Service is generally restricted to pursuing process maintenance objectives for vegetation within national parks and monuments. It is also pointed out that implementation of some process maintenance objectives is complicated by the need to return the forest community to its pre-fire exclusion state before reintroducing fire to the ecosystem. To do otherwise would perpetuate the changes in species composition and structure that have resulted from more than three-quarters of a century of fire exclusion. A new alternative for managing vegetation in national parks that is based on a high resolution description of the presettlement forest community, called the reconstruction-simulation approach, is also presented.
Uplifts, Hassles, and Adaptational Outcomes in Early Adolescents

The relationship of daily uplifts and hassles to adaptational outcomes has gained increasing attention in recent years. However, investigators have focused considerably more on hassles than uplifts. In an attempt to rectify this trend, the present study examines the relationship of uplifts and hassles to anxiety, depression, distress, self-restraint, perceived sup-port from friends, perceived social competence, and general self-worth in a sample of 23 sixth graders (141 girls). Results indicate that both hassles and uplifts are substantially related to these outcomes in the expected direction, with the exception of a modest positive association between uplift and anxiety for girls. Moreover, in most cases uplifts add significantly to the relationship between hassles and outcomes, thus high-lighting the importance of uplifts. Other findings idicate that uplifts/hassles patterns vary as a function of gender and the particular outcome being considered. Similarities to and differences from adult findings are ...