cssi/SciSciGPT-SciSciNet huggingface dataset:
Tip shape effects in scanning probe metrology

Recently, interest in the use of scanning probe microscopes (SPM) for metrology applications has grown. SPM can provide detailed topographical maps of reticles and wafers from which much useful data can be extracted. For example, CD measurements very near the bottom of sidewalls can be determined. Sidewall angles can be measured non-destructively. Micro-trenching (micro-loading) in etched quartz features on APSM can be characterized, and quartz bumps can be volume mapped for accurate dose control on FIB repair tools. The main issue complicating the use of SPM for metrology is the effect of tip shape and tip wear on the measurement data. For example, features with nearly vertical surfaces, like sidewalls, can't be measured accurately with conical tips because SPM scans will actually measure the sidewall of the tip and not the feature. This study will qualitatively address the issues associated with tip shape effects and discuss methods being employed to reduce or eliminate them.
Nitrite Mode of Action: Inhibition of Yeast Pyruvate Decarboxylase (E.C. 4.1.1.1) and Clostridial Pyruvate:Ferredoxin Oxidoreductase (E.C. 1.2.7.1) by Nitric Oxide

The effects of nitric oxide (NO) on the nonoxidative decarboxylation of pyruvate were studied using yeast pyruvate decarboxylase (PD) as a model. PD was inhibited by NO (50% inhibition 0.5 mM) under anaerobic but not under aerobic conditions. Prior inhibition by NO was not reversed by aerobic conditions. Sodium nitrite (0.5 mM) was not inhibitory. Inhibition of PD by NO was markedly enhanced in the presence of ascorbate. A preparation of pyruvate:ferredoxin oxidoreductase (PFO) from Clostridium perfringens (3624 A) was inhibited by NO (50% inhibition 0.025 mM) but not by sodium nitrite (1.0 mM). These results suggest that the thiamin dependent decarboxylation of pyruvate may be an additional site for the antimicrobial mode of action of nitrite independent of the iron-sulfur center of PFO and supports the concept that the active principle is NO.
On-road ads delivery scheduling and bandwidth allocation in vehicular CPS

We consider a promising application in Vehicular Cyber-Physical Systems (VCPS) called On-road Ad Delivery (OAD), where targeted advertisements are delivered via roadside APs to attract commuters to nearby shops. Different from most existing works on VANETs which only focused on a single technical area, this work on OAD involves technical elements from human factors, cyber systems and transportation systems since a commuter's shopping decision depends on e.g. the attractiveness of the ads, the induced detour, and traffic conditions on different routes. In this paper, we address a new optimization problem in OAD whose goal is to schedule ad messages and allocate a limited amount of AP bandwidth so as to maximize the system-wide performance in terms of total realized utilities (TRU) of the delivered ads. A number of efficient heuristics are proposed to deal with ad message scheduling and AP bandwidth allocation. Besides largescale simulations, we also present a case study in a more realistic scenario utilizing real traces collected from taxis in the city of Shanghai. In addition, we use a commercial traffic simulator (PARAMICS) to show that our proposed solutions are also useful for traffic management in terms of balancing vehicular traffic and alleviating congestion.
Racial and Ethnic Differences in Young Men's Sex and Contraceptive Education

Abstract Purpose Racial/ethnic disparities exist in young men's contraceptive knowledge. This study examines whether the likelihood of receiving sexual health education varies by race/ethnicity. Methods We examined racial/ethnic differences in sex and contraceptive education both in school and from parents with multivariable logistic regression models among 4,104 men aged 15–24 years using data from the 2006–2010 National Survey of Family Growth. Results Nearly all respondents (96.6%) reported formal sex education. Fewer reported formal birth control education (66.6%), parental sex discussions (66.8%), and parental discussions specifically about birth control (49.2%). In multivariable analysis, black men were less likely than white men to report receiving formal contraceptive education (adjusted odds ratio [aOR], .70; 95% CI, .51–.96). Both black and U.S.-born Hispanic men reported more parental sex discussions than white men (aOR, 1.44; 95% CI, 1.07–1.94, aOR, 1.47; 95% CI, 1.09–1.99, respectively). Conclusions Nearly all respondents reported having received formal sexual health education. Fewer reported receiving education about birth control either at school or at home. Black men were less likely to report receiving formal contraceptive education.
Isolation and characterization of the microflora of nixtamalized corn masa

Abstract Corn tortillas are a staple in the diet among the Mexican population, and are traditionally produced through a process known as nixtamalization. This traditional process involves steeping whole-kernel corn in an alkaline solution overnight and then grinding the corn into dough (masa), which is then baked. While the masa is held before baking, significant microbial change can occur which leads to fermentation and spoilage. The objective of this research was to characterize and identify the microflora of nixtamalized corn masa from six different commercial tortilla mills throughout Guadalajara, Mexico. The identification of samples was conducted using the microbial identification system (MIS), which analyzes cellular fatty acids via gas chromatography to identify bacterial species. Lactic acid bacteria and aerobic mesophiles were the predominant organisms, with both groups having counts ranging from 104 to 107 cfu/g across all mills. Coliform populations were observed at counts of 102 to 103 cfu/g, while yeast and mold counts were typically less than 101 cfu/g. Some mills showed no presence of coliforms or yeast or mold. Streptococcus bovis and Lactobacillus oris were isolated from all mills, and were the most prevalent organisms representing 43% and 17% of all lactic acid bacteria isolated, respectively. S. bovis was also isolated on the aerobic tryptic soy plates and was the most prevalent species representing 19% of the total organisms from these aerobic plates.
Decreased survival of C/EBP beta-deficient keratinocytes is due to aberrant regulation of p53 levels and function.

Recent studies have identified roles for C/EBPβ in cellular survival and tumorigenesis, however, the mechanisms through which C/EBPβ regulates these processes are not fully understood. Previously, we demonstrated that C/EBPβ−/− mice are resistant to carcinogen-induced skin tumorigenesis and in response to topical carcinogen treatment display a 17-fold increase in keratinocyte apoptosis compared to wild-type mice. Here, we have investigated the mechanisms through which C/EBPβ regulates apoptosis in response to carcinogenic stress. Analysis of carcinogen-treated C/EBPβ−/− mouse skin revealed a striking increase in the number of p53 immunopositive keratinocytes in the epidermis of C/EBPβ−/− mice compared to wild-type mice and this increase was temporally associated with a concomitant anomalous increase in apoptosis. The increased levels of p53 were functional as Mdm2, Bcl-2, C/EBPα and p21 were differentially regulated in the epidermis of carcinogen-treated C/EBPβ−/− mice. The increase in p53 protein was not associated with an increase in p53 mRNA levels. To determine whether p53 is required for the increased apoptosis in C/EBPβ−/− mice, C/EBPβ/p53 compound knockout mice were generated. Carcinogen-treated C/EBPβ/p53 compound knockout mice did not display increased apoptosis demonstrating p53 is required for the proapoptotic phenotype in C/EBPβ−/− mice. Our results demonstrate that altered keratinocyte survival in C/EBPβ−/− mice results from aberrant regulation of p53 protein and function and indicate C/EBPβ has a role in the negative regulation of p53 protein levels in response to carcinogen-induced stress.
Petroleum films exposed to sunlight produce hydroxyl radical

Abstract Sunlight exposed oil films on seawater or pure water produced substantial amounts of hydroxyl radical as a result of irradiation. Oil was collected from the surface of the Gulf of Mexico following the Deepwater Horizon spill and exposed to simulated sunlight in thin films over water. Photochemical production of hydroxyl radical was measured with benzoic acid as a selective chemical probe in the aqueous layer. Total hydroxyl radical formation was studied using high benzoic acid concentrations and varying exposure time. The total amount of hydroxyl radical produced in 24 h irradiations of thin oil films over Gulf of Mexico water and pure water were 3.7 × 10−7 and 4.2 × 10−7 moles respectively. Steady state concentrations of hydroxyl radical were measured using a competition kinetics approach. Hydroxyl radical concentrations of 1.2 × 10−16 to 2.4 × 10−16 M were observed for seawater and pure water under oil films. Titanium dioxide (TiO2) nanomaterials were added to the system in an effort to determine if the photocatalyst would enhance oil photodegradation. The addition of TiO2 nanoparticles dramatically changed the observed formation rate of hydroxyl radical in the systems with NP water at pH 3, showing increased formation rate in many cases. With photocatalyst, the steady state concentration of radical decreased, predominantly due to an increase in the hydroxyl radical scavenging rate with oxide present. This study illustrates that oil is a strong and important source of hydroxyl radical when exposed to sunlight. The fate of oil and other dissolved species following oil spills will be heavily dependent on the formation and fate of hydroxyl radical.
Deposition of charged particles in a channel

Abstract Deposition of particles in a parallel-plate channel under the influence of inertia, viscous, gravity and electrostatic image forces was studied using a trajectory method. A laminar fluid flow of uniform and fully-developed velocity profiles is assumed and the fluid is suspended with particles having the same velocity as the fluid at the inlet plane. A trajectory method was employed to find the trajectory of each particle entering the channel. The governing equations were solved with the fourth-order Runge-Kutta method. Depositions were calculated based on the distance for a particle to reach the wall. The deposition increases with increasing gravity effect and image force effect. The image force effects dominate the flow when the ratio of the charge parameter Q to the gravity parameter G is greater than 5 and diminishes when the ratio is less than 0.001. The inertia force increases with increasing particle size and results in higher deposition while the viscous force decreases the deposition. The uniform flow gives higher deposition than the fully-developed flow.
Targeting of the domain‐specific integral membrane protein PM52 to the periacrosomal plasma membrane during guinea pig spermiogenesis

The sperm plasma membrane is segregated into functionally, biochemically, and structurally distinct domains yet the protein sorting pathways and assembly mechanisms that assemble these domains during spermiogenesis are incompletely understood. We previously characterized two structurally related size-variant, integral membrane proteins of 52 kDa (PM52) and 35 kDa localized to the periacrosomal plasma membrane of guinea pig cauda epididymal spermatozoa (Westbrook-Case et al., 1994). In this study we used light and electron microscopic immunocytochemistry to define the expression pattern and sorting pathway that establishes the domain-specific distribution of PM52 during spermiogenesis. The PM52 is first expressed in acrosome-phase spermatids and it localizes exclusively to the cytoplasmic lobe. Immunoelectron microscopy revealed that both cytoplasmic vesicles and the plasma membrane of the cytoplasmic lobe labeled with anti-PM52. During early stages of expression, PM52 appeared to be absent from the head region, but significant PM52 accumulation over the spermatid head was noted in late acrosomal phase spermatids. Throughout spermiogenesis PM52 extended posteriorly to the annulus, which represents a barrier preventing PM52 diffusion into the posterior tail. Following the migration of the annulus to the midpiece-principal piece junction, PM52 began to disappear from the flagellar region and at the completion of spermiogenesis most of the PM52 was restricted to the acrosomal segment. Spermatids and epididymal sperm PM52 exhibited identical sizes by SDS-PAGE and immunoblotting, indicating that they are not proteolytically modified during epididymal maturation. The PM52 antibodies were also used to screen a guinea pig testis cDNA library, and sequence determination of full-length PM52 clones demonstrated identity of a sperm membrane protein recently termed "sperad" (Quill and Garbers, 1996). Membrane barriers and potential mechanisms establishing the domain-specific residence of PM52 are discussed.
Melt segregation driven by dynamic forcing

Melt segregation can be driven by suction applied to the free surface of a partially molten region (dynamic forcing). Dynamic forcing may play a role in drawing melt towards eruption centers or in maintaining melt channels within the mantle. I examine the importance of dynamic forcing by means of a model in which melt is extracted by suction from a deformable porous medium with initially uniform porosity. The suction rapidly reduces the porosity near the free surface, and the melt extraction rate drops to zero after about 10³ yr. The total volume of melt extracted during this time is only about 0.05 km³ per km² of free surface area. These results suggest that dynamic forcing probably plays a negligible role in melt segregation, and that melt channels are unlikely to exist in the mantle.
The Price of Expertise: Effects of Experience on the Water-Level Task

When shown a tilted container, people often fail to appreciate that the surface of the liquid contained within should remain horizontal with respect to the ground This study investigated how amenable this bias is to experience in relevant everyday situations Surprisingly, liquid surfaces that waitresses and bartenders considered natural deviated even more from horizontal than was the case for comparison groups This finding is, to our knowledge, the only documented case in which performance declines with experience We suggest that practical experience promotes a functionally relative perspective, in which the orientation of the liquid's surface is evaluated relative to that of its container as opposed to being related directly to the surrounding environment The container-relative perspective, in turn, evokes a perceptual bias that is responsible for the systematic errors observed on this task
A periodicity of tritiated-thymidine incorporation into cytoplasmic deoxyribonucleic acid during the cell cycle of Tetrahymena pyriformis.

REPORTS indicate that 3H-thymidine is incorporated into a DNase-sensitive material in the cytoplasm of the ciliate Tetrahymena pyriformis1–5. It is now known that most of this cytoplasmic DNA is localized inside the mitochondria of this species1. Furthermore, this cytoplasmic DNA appears to be stable and conserved during cell growth and reproduction1,4.
Critical urban collaborative ethnographies: articulating community with Sappho for Equality in Kolkata, India

This article reflects on the notion of community through a collaborative ethnographic study with women loving women in Kolkata. Performing critical urban ethnographies in the global south and writing about sexualities that defy easy spatial categorizations are vital for those who seek to extend the scholarship of sexualities beyond the ‘gayborhood paradigm’ in the global north. This article focuses on how women loving women understand community and activism in Kolkata, a city that exists within tireless attempts at economic rejuvenation and vibrant modes of living. The question of community is moot in political activism around decriminalization of same-sex relationships and social legitimacy of the same. Drawing on collaborative ethnographic work with Sappho for Equality, an activist collective working with sexually marginalized women in eastern India, we engage with community as a space through which women loving women articulate marginalization and strategically connect with normative social institution...
Numerical optimization of the micromagnetics energy

The numerical computation of the minimum energy for a ferromagnetic material with a fine domain structure modeled by the theory of micromagnetics is difficult because the bulk energy has many local minima and because the optical magnetization can have many domains. We show that an efficient implementation of the simulated annealing algorithm can be used to compute the magnetization which has the minimum energy.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
What if you build it, and they keep coming and coming and coming?

Purpose – To provide an overview of building use in Lied Library at UNLV from the Library's opening in 2001 through early 2004 and to provide and update on the implications of the ramifications of that use for staff and users.Design/methodology/approach – Use and visitation statistics are highlighted and factors associated with the use, such as overall design, policy changes, new services and resources as well as campus context are presented.Findings – The experiences at UNLV's Lied Library indicate that the concept of “library as place” still matters; that an awe‐inspiring and esthetically pleasing design can produce a very functional building and that still matters; that continually evolving user‐focused services still matter; and that, for the library to continue to matter in the lives of its users, it must continue to adapt to its campus context, to collaborate successfully with campus partners and to respond effectively to the constantly changing context of information delivery and knowledge promotio...
With a little help from my friends: complementation as a survival strategy for viruses in a long-lived host system.

Abstract In selective host species, the extent of Citrus tristeza virus (CTV) infection is limited through the prevention of long-distance movement. As CTV infections often contain a population of multiple strains, we investigated whether the members of a population were capable of interaction, and what effect this would have on the infection process. We found that the tissue-tropism limitations of strain T36 in selective hosts could be overcome through interaction with a second strain, VT, increasing titer of, and number of cells infected by, T36. This interaction was strain-specific: other strains, T30 and T68, did not complement T36, indicating a requirement for compatibility between gene-products of the strains involved. This interaction was also host-specific, suggesting a second requirement of compatibility between the provided gene-product and host. These findings provide insight into the ‘rules’ that govern interaction between strains, and suggest an important mechanism by which viruses survive in a changing environment.
Intraarticular anterior cruciate ligament reconstruction in the symptomatic arthritic knee

We reviewed a consecutive series of young sympto matic patients with chronic anterior cruciate ligament- deficient knees to determine if an autogenous patellar tendon graft reconstruction decreased their symptoms and increased the stability of the knee. All patients had radiographic evidence of posttraumatic arthritis. Thirty- three patients met our criteria for inclusion in the study. Time from injury to reconstruction of the anterior cru ciate ligament averaged 105 months. All patients under went an accelerated rehabilitation program designed to help them regain full range of motion as soon as pos sible. Preoperative and postoperative range of motion, strength, stability, and subjective evaluations were compared. Followup averaged 44.8 months. Follow-up range of motion was not significantly different from preoperative measurements (P = 0.51). Postoperative stability, as measured by KT-1000 arthrometer maxi mum manual test, averaged 2.7 mm versus 8.4 mm preoperatively (P < 0.001). Isokinetic testing reve...
Responding to Questions About Thoughts Attenuates Responses to Questions About Feelings: Further Exploration of the Situational Self-Statement and Affective State Inventory

The Situational Self-Statement and Affective State Inventory (SSSASI) assesses specific thoughts and feelings in response to 5 vignettes describing frustrating events. In its original form, participants responded to a series of 5 self-statements (thoughts), then 5 affective state descriptors (feelings), following each vignette. Recent research has shown that a parallel form of the SSSASI in which the feelings precede the thoughts produces significantly higher scores on many of the feelings categories. Responding to the thoughts before the feelings significantly attenuates scores on the feelings, but responding to the feelings before the thoughts has no effect on scores on the thoughts. To test the limits of this phenomenon, we studied 6 parallel forms of the SSSASI, each with a different number of thoughts preceding the feelings. The results show that increasing the numbers of thoughts presented before the feelings tends to produce progressively lower scores on the feelings. If we assume that stronger endorsements of feelings are more valid reflections of respondents' genuine initial reactions to frustrating events, then the implications are that a preferable format for the SSSASI—and, presumably, similar inventories assessing thoughts and feelings—is that in which participants respond to questions about feelings before they respond to questions about thoughts.
Quinolinate synthetase: the oxygen-sensitive site of de novo NAD(P)+ biosynthesis

The ability of niacin to relieve the growth-inhibiting effect of hyperoxia on Escherichia coli can be attributed to the dioxygen sensitivity of quinolinate synthetase. The activity of this enzyme within E. coli was diminished by exposure of the cells to 4.2 atm O2, while the activity in extracts was rapidly decreased by 0.2 atm O2. Neither catalase nor superoxide dismutase afforded detectable protection against the inactivating effect of O2, indicating that H2O2 and O2- were not significant intermediates in this process. Nevertheless, H2O2 at 1.0 mM did inactivate quinolinate synthetase, even under anaerobic conditions and in the absence of catalatic activity which might have generated O2. Addition of paraquat to aerobic cultures of E. coli caused an inactivation of quinolinate synthetase, which may be explained in terms of an increase in the production of H2O2. The O2-dependent inactivation of quinolinate synthetase in extracts was gradually reversed during anaerobic incubation and this reactivation was blocked by alpha, alpha'-dipyridyl or by 1,10-phenanthroline. The sequence of the quinolinate synthetase "A" protein contains a--cys-w-x-cys-y-z-cys--sequence, which is characteristic of (Fe-S)4-containing proteins. This sequence, together with the effect of the Fe(II)-chelating agents, suggests that the O2-sensitive site of quinolinate synthetase is an iron-sulfur cluster which is essential for the dehydration reaction catalyzed by the A protein.
Proton polarization measurements near isobaric analogue resonances in 145Eu

Abstract Measurements of the polarization of elastically scattered protons have been carried out to determine the total angular momenta of the isobaric analogues of the ground state and of the first two p-states in 145Sm. They were found to be J π = 7 2 − , 3 2 − and 1 2 − , respectively. The assignment of J π = 1 2 − for the second l = 1 state is disagreement with previous assignments.
Elastic scattering by an obstacle in a half-space bounded by a penetrable interface

The solution for the problem of an elastic obstacle in the presence of a penetrable half-space excited by a dyadic elastic wave is given. Integral equations and algebraic solutions are obtained by considering the non-embedding half-space as an obstacle. Explicit results for scatterers which are small compared to all wavelengths involved are derived as well as asymptotic results for large distances from the interface.
Identification of a Murine Locus Conveying Susceptibility to Cadmium-Induced Forelimb Malformations

The heavy metal cadmium (Cd), an environmentally ubiquitous contaminant, is a potent teratogen in mice. When administered parenterally, it induces an array of malformations that vary in scope and severity with the route, dose, time of administration, and the strain of the animal. When administered intraperitoneally on day 9.0 of gestation, 4 mg/kg cadmium chloride produces forelimb defects (predominantly ectrodactyly) in over 80% of fetuses of the C57BL/6 mouse strain, while no limb defects are observed in the identically treated SWV strain. Like other examples of strain-specific teratogenic activity, the underlying nature of the differential susceptibility remains unknown. The present study investigates the segregation of sensitivity to Cd-induced forelimb defects in crosses between C57BL/6 and SWV mice and provides evidence for the involvement of both maternal and fetal factors in the determination of defect expression. In addition, quantitative trait loci (QTL) analysis of the fetal genetic component was performed among 198 backcross progeny, utilizing a genomic linkage map of 149 informative microsatellite markers. One QTL demonstrating significant linkage to expression of the defect, designated Cadfar (cadmium-induced forelimb autopod reduction), was mapped to the distal end of chromosome 6 with a lod score of 3.1.
Elicitation of 6‐Methoxymellein in Carrot Leaves by Cercospora carotae

The inoculation of carrot leaves with conidia of the fungus Cercospora carotae induced the accumulation of 6-methoxymellein in the leaf blade and petiole, but not the root, of susceptible carrot plants. Root slices directly inoculated with mycelium of C carotae also accumulated 6-methoxymellein. In leaves, the peak in 6-methoxymellein levels coincided with the appearance of the first lesions, 9 days after inoculation. After this point the compound started to degrade steadily. This phytoalexin could thus be a defence compound against foliar pathogens of carrot. © 1997 SCI.
Influence of veratridine on [3H]-L-quinuclidinyl benzilate ([3H]QNB) binding in mouse hindbrain.

Abstract The neurotoxin veratridine is well known for its ability to open sodium channels in neuronal and muscle tissues in micromolar concentrations. It has also been shown that veratridine is an inhibitor of the potent muscarinic receptor antagonist l -quinuclidinyl benzilate (QNB) at these concentrations. These findings prompted us to examine the relationships between action potential sodium channels and muscarinic receptors in a glass-fiber filtration assay for [ 3 H]QNB binding to mouse hindbrain membranes using agents known to affect interconversion of the affinity states in some muscarinic receptor populations, i.e. guanosine triphosphate (GTP) and magnesium (Mg 2+ ). The actions of the sodium channel antagonist tetrodotoxin (TTX) were also examined. Veratridine inhibited [ 3 H]QNB binding with a K i , value of approximately 2.5 μM. This inhibition exhibited a competitive mechanism at higher concentrations (5–10 μM), while showing an apparent non-competitive action at low concentrations (1 μM). Magnesium caused a parallel shift to the right in the inhibition curve with a 32% increase in the veratridine K i . GTP caused a non-parallel shift to the left with the greatest displacement occurring at lower veratridine concentrations (2–5 μM). The addition of magnesium to GTP did not alter the action of GTP significantly. TTX (5 μM) caused a parallel shift of the veratridine inhibition curve to the right. In addition, TTX alone inhibited the binding of [ 3 H]QNB. Therefore, it appears that there may be more than one binding site for veratridine which may be linked to the muscarinic system and that these may be action potential sodium channels.
The Very First Stars: Formation and Reionization of the Universe

One of the key challenges for the next 10 years is to understand the first sources of light, the first stars and possibly accreting black holes. Their formation ended the cosmic dark ages at redshifts z ≃ 20 − 30, and signaled the transition from the simple initial state of the universe to one of ever increasing complexity. We here review recent progress in understanding the formation process of the first stars with numerical simulations, starting with cosmological initial conditions and modelling the detailed physics of accretion. Once formed, the first stars exerted crucial feedback on the primordial intergalactic medium, due to their input of radiation and of heavy chemical elements in the wake of supernova explosions. The current theoretical model posits that the first stars were predominantly very massive, typically ~100 M⊙. Our predictions will be tested with upcoming near-infrared observatories, such as the James Webb Space Telecope, in the decade ahead.
What do mouse gene knockouts tell us about the structure and function of the red cell membrane

Abstract Recent development of knockout mice with targeted deletion of specific genes encoding various red cell membrane proteins has added valuable armamentarium to red cell membrane structure–function studies. In this chapter we will summarize the various recent developments regarding the structure and function of the red cell membrane derived from studies using knockout mice. In addition to being expressed in red cells, all major red cell membrane proteins are also expressed in cells of various tissues. The potential use of knockout mice to decipher the biological functions of red cell membrane proteins in non-erythroid cells is also explored.
Comparison of a chlorophyll a- protein complex isolated from a blue-green alga with chlorophyll-protein complexes obtained from green bacteria and higher plants.

Abstract 1. 1. An improved procedure has been devised for the purification of large quantities of a detergent-soluble chlorophyll a-protein complex (λmax 677 nm) from a blue-green alga. The complex, which is pure by the criteria of gel electrophoresis and ultracentrifugation, contains approx. 70% of the chlorophyll a of the organism. Studies of the composition of the complex indicate that the protein moiety is probably made up of subunits (mol. wt. 35000), each of which contains five moles of chlorophyll and a trace of β-carotene and echinonone. 2. 2. Comparison of the physical and chemical properties of the algal chlorophyll-protein complex with those of a water-soluble bacteriochlorophyll-protein of green bacteria, and another detergent-soluble chlorophyll a-protein complex of higher plants suggests that all photosynthetic organisms might contain an analogous class of chlorophyll-proteins (mol. wt. 150000–160000), which are associated with photo-chemical system I activity, and which are composed of four identical protein subunits and 20 moles of chlorophyll. 3. 3. The water insolubility of the algal and higher plant chlorophyll-protein complexes is most probably explained by the presence of apolar amino acid residues on the surface of the molecule. In vivo the chlorophyll a-proteins are postulated to be attached to the lamellar membrane by hydrophobic bonding of the apolar regions to the lamellar lipids. 4. 4. Comparative studies indicate that the algal and higher plant complexes are much more closely related to each other than to the bacterial complex.
Family Functioning Patterns as Predictors of Engagement: Which Families Participate in Services and Which Ones Do Not?

ABSTRACT The present study examines the relationship between specific areas of family functioning and family engagement in prevention services. A sample of 147 families who initiated youth-centered treatment services from a non-profit agency was selected. Statistical analysis was used to test for relationships between family scores on the Family Assessment Measure (version III, General Scale) and family levels of engagement in services. Results of binary logistic regression analysis indicated that individual and family characteristics are associated with family engagement in services. In addition to demographic variables of age and race, family patterns of denial made a significant individual contribution to the evaluated model. Implications for engaging families in prevention services are discussed and suggestions are made for future research.
Effect of organic anions on the crystallization of the Ca2(+)-ATPase of muscle sarcoplasmic reticulum.

Abstract The effect of varying the solute species on the crystallization of the Ca 2+ -ATPase from rabbit muscle reticulum (SR) is reported. We have found that substitution of KCl with salts of organic acids in the crystallization protocol reported by Pikula et al. [1] has a profound effect on the size of two-dimensional crystalline arrays. Crystalline arrays of up to 3 μm diameter have been obtained by incubating purified calcium ATPase in standard crystallization medium but with 0.8 M sodium propionate substituted for KCl. These two-dimensional (2-D) arrays display a reduced tendency to stack in addition to having larger planar dimensions. Increasing the KCl concentration does not have the same effect on stacking or crystal growth that sodium propionate has. The production of 2-D sheets has some dependence on the hydrocarbon chain length of the salt because crystals formed in propionate were larger and less stacked than those formed in acetate or formate. There seems to be no dependence on cation. These observations suggest that in addition to reducing the forces that lead to stacking of the sheets, propionate may facilitate incorporation of the detergent-solubilized protein into the 2-D sheet.
On the counter-cyclicality of prices and markups in a Cournot model of entry

Abstract We prove in a Cournot model that the price and markup are counter-cyclical due to changes in the extent of competition if the income effect is decreasing in the price, as occurs when preferences are homothetic or demand is isoelastic.
SOME ASPECTS OF THE KAPITZA RESISTANCE

The Kapitza resistance of tin and indium, in both the superconducting and normal states, and sapphire have been mesaured in the temperatare range of 1.3 to 2 deg K. The results are compared with those reported for superconducting and normal lead as well as with the predicted values from current theory. Although quaiitative agreement with the theory is obtained, large discrepancies in the absolute value of the Kapitza registance as well as its temperature dependence for metals in their superconducting state are observed, suggesting the existence of other, as yet undiscovered, parallel mechanisms. The effect of electric field on the Kapitza resistance between platinum and liquid helium was investtgated with the hope of determining the influence of the coupling between the phonons of the liquid and the part of the electronic wave functions of the metal which decay into the liquid on the Kapitza resistance. Under our experimental conditions, no effect is observed. (auth)
Omitted variables in longitudinal data models

The omission of important variables is a well-known model specification issue in regression anal- ysis and mixed linear models. The author considers longitudinal data models that are special cases of the mixed linear models; in particular, they are linear models of repeated observations on a subject. Models of omitted variables have origins in both the econometrics and biostatistics literatures. The author describes regression coefficient estimators that are robust to and that provide the basis for detecting the influence of certain types of omitted variables. New robust estimators and omitted variable tests are introduced and illustrated with a case study that investigates the determinants of tax liability.
Subcellular Distribution and Macromolecular Binding of Aflatoxin in Fetal and Neonatal Rat Liver

The aflatoxins are mycotoxins produced by several species of Aspergillus, aflatoxin B1 (B1) being the most potent hepatotoxic and hepatocarcinogenic compound among these metabolites. There is a wide variation in susceptibility to B1 among animal species and sexes.23 Considerable research has been undertaken on biochemical mechanisms of the action of aflatoxin in relation to the species and sex differences. Formation of B1-8,9-epoxide by the cytochrome P-450 enzyme system and subsequent binding to DNA are regarded as critical steps of the carcinogenic effect of B1. 1,21,24,29,31 The importance of formation of the B1-glutathione conjugate by cytosolic glutathione S-transferase in inactivation of B1-epoxide has been well documented in relation to species and sex differences of the B1 effects. 3,4,18,22,27
A framework for modeling influence, opinions and structure in social media

The Blogosphere provides an interesting opportunity to study social interactions. Blogs provide a channel to express opinions, facts and thoughts. Through these pieces of information, also known as memes, bloggers influence each other and engage in conversations that ultimately lead to exchange of ideas and spread of information. We aim to characterize and model the Blogosphere to study the spread of influence, opinion formation and social interaction. Further, we propose a simple generative process that models creation and evolution of blogs. This model is an extension of existing preferential attachment and random surfer model. Using available samples of the Blogosphre (represented as a blog graph) and the proposed generative model, we hypothesize, compare and validate different approaches to modeling influence and opinion formation in social media.
Structure of the SAM-II riboswitch bound to S-adenosylmethionine

In bacteria, numerous genes harbor regulatory elements in the 5′ untranslated regions of their mRNA, termed riboswitches, which control gene expression by binding small-molecule metabolites. These sequences influence the secondary and tertiary structure of the RNA in a ligand-dependent manner, thereby directing its transcription or translation. The crystal structure of an S-adenosylmethionine–responsive riboswitch found predominantly in proteobacteria, SAM-II, has been solved to reveal a second means by which RNA interacts with this important cellular metabolite. Notably, this is the first structure of a complete riboswitch containing all sequences associated with both the ligand binding aptamer domain and the regulatory expression platform. Chemical probing of this RNA in the absence and presence of ligand shows how the structure changes in response to S-adenosylmethionine to sequester the ribosomal binding site and affect translational gene regulation.
Dual Regulation of δ-Opioid Receptor Function by Arachidonic Acid Metabolites in Rat Peripheral Sensory Neurons

The regulation of opioid receptor system function in peripheral sensory neurons is not well understood. Opioid agonist efficacy to inhibit nociceptor function and to promote antinociception is generally weak under basal conditions and frequently no response occurs. However, in response to a cyclooxygenase-dependent metabolite of arachidonic acid (AA) after exposure to inflammatory mediators, such as bradykinin (BK) or exogenous AA, peripheral opioid receptor systems become much more responsive to opioid agonists. In this study, we examined the time course for the induction and maintenance of functional competence of the δ-opioid receptor (DOR) system in adult rat nociceptors in culture and in vivo. We found that the responsive state of DOR after pretreatment with BK or exogenous AA is transient (30–60 minutes) and persists for 15–30 minutes after a 15-minute exposure of nociceptors to BK or AA. Interestingly, whereas functional competence of the DOR system could be reinduced with a second application of BK 60 minutes after the first, responsiveness of the DOR system could not be reinduced after an initial exposure to AA. This nonresponsive state of DOR after exogenous AA was mediated by a lipoxygenase (LOX)-dependent metabolite of AA. Intraplantar carrageenan also produced transient DOR functional competence and responsiveness was also reinduced by inhibition of LOX. Thus, the DOR system expressed by peripheral sensory neurons is under dual regulation by cyclooxygenase- and LOX-dependent metabolites of AA.
Object model creation from multiple range images: acquisition, calibration, model building and verification

This paper demonstrates the accuracy of a prototype Laser Range Camera (LRC) developed at the National Research Council of Canada for the creation of models of real objects. A laser survey performed in collaboration with the Canadian Space Agency and NASA is used as a test case. The object selected for this particular test case is the Orbiter Docking System (ODS) located at the Kennedy Space Center, Florida. During the laser survey, 128 range (and registered intensity) images were acquired all around the ODS. These images were then processed in our laboratory. A full model of the top portion of the ODS was created along with an almost complete model of the ODS. The ODS has a diameter of 1.6 m and a height of 3.9 m. Targets mounted on the top portion of the ODS were used to assess the accuracy of the calibration and of the image registration process. These targets were measured with a network of theodolites a day prior to the laser survey and used as a reference. With the current calibration and range image registration techniques, an accuracy better than 0.25 mm in X and Y, and, 0.80 mm in Z was achieved. These results compare favorably with the single point accuracy obtained after calibration, i.e., about 0.25 mm in X and Y, and, 0.50 mm in Z. These figures and others should testify on the usefulness of a LRC for accurate model building.
Wind extraction potential from 4D-Var assimilation of stratospheric O 3 , N 2 O, and H 2 O using a global shallow water model

Abstract. The wind extraction due to assimilation of stratospheric trace gas (tracer) data is examined using a 4D-Var (four-dimensional variational) data assimilation system based on the shallow water equations coupled to the tracer continuity equation. The procedure is outlined as follows. First, a nature run is created, simulating middle stratospheric winter conditions. Second, ozone (O3), nitrous oxide (N2O), and water vapor (H2O) (treated in this study as passive tracers) are initialized using Aura Microwave Limb Sounder (MLS) mixing ratios at 850 K potential temperature and are advected by the nature run winds. Third, the initial dynamical conditions are perturbed by using a 6 h offset. Fourth, simulated hourly tracer observations on the full model grid are assimilated with a 4D-Var system in which tracer and winds are coupled via the adjoint of the tracer continuity equation. Multiple assimilation experiments are performed by varying the amount of random observation error added to the simulated measurements. Finally, the wind extraction potential (WEP) is calculated as the reduction of the vector wind root mean square error (RMSE) relative to the maximum possible reduction. For a single 6 h assimilation cycle with the smallest observation error, WEP values are ~60% for all three tracers, while 10-day multi-cycle simulations result in WEP of ~90%, wind errors of ~0.3 m s−1, and height errors of ~13 m. There is therefore sufficient information in the tracer fields to almost completely constrain the dynamics, even without direct assimilation of dynamical information. When realistic observation error is added (based on MLS precisions at 10 hPa), the WEP after 10 days is 90% for O3, 87% for N2O, and 72% for H2O. O3 and N2O provide more wind information than H2O due to stronger background gradients relative to the MLS precisions. The RMSE for wind reach a minimum level of ~0.3–0.9 m s−1 for the MLS precisions, suggesting a limit to which realistic tracers could constrain the winds, given complete global cover age. With higher observation noise levels, the WEP values decrease, but the impact on the winds is still positive up to noise levels of 100% (relative to the global mean value) when compared to the case of no data assimilation.
Growth of Streptococcus faecalis under High Hydrostatic Pressure and High Partial Pressures of Inert Gases

Growth of Streptococcus faecalis in a complex medium was inhibited by xenon, nitrous oxide, argon, and nitrogen at gas pressures of 41 atm or less. The order of inhibitory potency was: xenon and nitrous oxide > argon > nitrogen. Helium appeared to be impotent. Oxygen also inhibited streptococcal growth and it acted synergistically with narcotic gases. Growth was slowed somewhat by 41 atm hydrostatic pressure in the absence of narcotic gases, but the gas effects were greater than those due to pressure. In relation to the sensitivity of this bacterium to pressure, we found that the volume of cultures increased during growth in a volumeter or dilatometer, and that this dilatation was due mainly to glycolysis. A volume increase of 20.3 ± 3.6 ml/mole of lactic acid produced was measured, and this value was close to one of 24 ml/mole lactic acid given for muscle glycolysis, and interestingly, close to the theoretic volume increase of activation calculated from the depression of growth rate by pressure.
Establishing discriminative control of responding using functional and alternative reinforcers during functional communication training

Functional communication training (FCT) is a popular treatment for problem behaviors, but its effectiveness may be compromised when the client emits the target communication response and reinforcement is either delayed or denied. In the current investigation, we trained 2 individuals to emit different communication responses to request (a) the reinforcer for destructive behavior in a given situation (e.g., contingent attention in the attention condition of a functional analysis) and (b) an alternative reinforcer (e.g., toys in the attention condition of a functional analysis). Next, we taught the participants to request each reinforcer in the presence of a different discriminative stimulus (SD). Then, we evaluated the effects of differential reinforcement of communication (DRC) using the functional and alternative reinforcers and correlated SDs, with and without extinction of destructive behavior. During all applications, DRC (in combination with SDs that signaled available reinforcers) rapidly reduced destructive behavior to low levels regardless of whether the functional reinforcer or an alternative reinforcer was available or whether reinforcement for destructive behavior was discontinued (i.e., extinction).
Unprecedented recent summer warmth in Arctic Canada

[1] Arctic air temperatures have increased in recent decades, along with documented reductions in sea ice, glacier size, and snow cover. However, the extent to which recent Arctic warming has been anomalous with respect to long-term natural climate variability remains uncertain. Here we use 145 radiocarbon dates on rooted tundra plants revealed by receding cold-based ice caps in the eastern Canadian Arctic to show that 5000 years of regional summertime cooling has been reversed, with average summer temperatures of the last ~100 years now higher than during any century in more than 44,000 years, including the peak warmth of the early Holocene when high-latitude summer insolation was 9% greater than present. Reconstructed changes in snowline elevation suggest that summers cooled ~2.7°C over the past 5000 years, approximately twice the response predicted by Coupled Model Intercomparison Project Phase 5 climate models. Our results indicate that anthropogenic increases in greenhouse gases have led to unprecedented regional warmth.