cssi/SciSciGPT-SciSciNet huggingface dataset:
Ozone-temperature relationships in the stratosphere

Utilizing independent estimates of ozone and temperature fields from the SBUV (Nimbus 7) and NOAA operational satellites, respectively, for the period 1978–1981, we have determined the coefficient of variation between the two parameters. This coefficient is defined as A= ∆03.[T] /∆T.[O3]where ∆ is an incremental change in either temperature or ozone and the bracket is a mean state. In practice, A is determined on a daily basis by regression of ozone mixing ratio versus temperature around a latitude circle during the winter season and the bracket value is the daily zonal average. This has the advantage of keeping the solar zenith angle fixed for a daily value while allowing it to change during the season. This is done at 30, 10, 5, 2, and 1 mb from 20° to 60° latitude in both hemispheres. The results are summarized and compared with those determined from a one-dimensional photochemical model applied to different latitudes.
Molecular Phylogenetic Investigation of U.S. Invasive Tamarix

Abstract Tamarix is a taxonomically difficult Old World genus that has become naturalized and invasive in the Americas and Australia. We examine the morphology and taxonomic history of 12 putative U.S. invasive Tamarix species, and investigate current invasions using chloroplast and nuclear sequence data. We test molecular phylogenetic hypotheses regarding the relationships of putative invasive taxa, and conclude that there are four invasive entities in the U.S., two of which are T. aphylla and T. parviflora. The sequence data also identify an invasive entity consisting of genetically indistinguishable T. ramosissima and T. chinensis, and another consisting of genetically indistinguishable T. gallica and T. canariensis. There is evidence of introgression between T. ramosissima, T. canariensis, and T. gallica, which is a likely source of confusion in the identification of some Tamarix invasions. Communicating Editor: Jeff H. Rettig
Using transactivity in conversation for summarization of educational dialogue.

We present our ongoing work towards using the concept of transactivity [1] for automatically assessing learning of students working together in a collaborative setting. Transactive segments of student dialogue are proposed as useful components of conversation summaries generated for instructors. Experimental evaluation of this hypothesis shows promising results. Further, initial results are presented for automatic identification of transactive contributions in student dialogue.
Penile Skin Bridges after Circumcision.

We herein present a healthy 13-year-old adolescent, who complaint of tightening and tugging of his penis during erections. He was circumcised at the age of three year. Clinical examination revealed three skin bridges at 3, 11 and 12 o’clock position, with a width of about 2-3 mm each. These acted as bridles during erections (Fig. 1). The bridges were surgically excised under general anesthesia using electrocautery, with no bleeding. There was no recurrence three months after surgery.
Differential Alterations in Host Peripheral Polymorphonuclear Leukocyte Chemiluminescence During the Course of Bacterial and Viral Infections

Abstract Previous studies have shown that stimulation of the oxidative metabolism in polymorphonuclear leukocytes (PMN) by in vitro phagocytosis of various microorganisms results in photon emission, termed chemiluminescence (CL). Studies were conducted to determine whether bacterial and viral infections induce enhanced basal endogenous host peripheral PMN CL in the absence of in vitro phagocytic stimulation. Nonimmune rats and guinea pigs as well as immune rats were inoculated with various doses (105 to 107) of live vaccine strain Francisella tularensis (per 100 g of body weight). In addition, nonimmune guinea pigs were inoculated with 40,000 plaque-forming units of Pichinde virus. Luminol-assisted endogenous PMN CL was measured at various time intervals after inoculation of microorganisms. Enhanced endogenous PMN CL was detected as early as the appearance of fever (12 h) in nonimmune animals infected with F. tularensis. Addition of sodium azide, N-ethylmaleimide, superoxide dismutase, or catalase to the CL reaction mixture containing PMN from infected animals significantly decreased the CL response. Immune rats challenged with F. tularensis exhibited resistance to infection and a decreased PMN CL compared with nonimmune rats 24 and 48 h after inoculation. However, the CL response from immune rats was significantly elevated, compared with control values. In contrast to the results obtained with the model bacterial infection, PMN isolated from guinea pigs inoculated with Pichinde virus failed to exhibit enhanced CL, compared with controls, despite significant viremia and fever. Results suggest that enhanced endogenous CL during bacterial infection occurs through mechanisms involving increased PMN oxidative metabolism and the subsequent generation of microbicidal forms of oxygen. Further, measurement of endogenous PMN CL may have diagnostic and prognostic value in infectious diseases.
COMMUNITY CHANGE IN THE VARIABLE RESOURCE HABITAT OF THE ABYSSAL NORTHEAST PACIFIC

Research capable of differentiating resource-related community-level change from random ecological drift in natural systems has been limited. Evidence for nonrandom, resource-driven change is presented here for an epibenthic megafauna community in the abyssal northeast Pacific Ocean from 1989 to 2004. The sinking particulate organic carbon food supply is linked not only to species-specific abundances, but also to species composition and equitability. Shifts in rank abundance distributions (RADs) and evenness, from more to less equitable, correlated to increased food supply during La Nina phases of the El Nino Southern Oscillation. The results suggest that each taxon exhibited a differential response to a sufficiently low dimension resource, which led to changes in community composition and equitability. Thus the shifts were not likely due to random ecological drift. Although the community can undergo population-level variations of one or more orders of magnitude, and the shape of the RADs was variable, the organization retained a significant consistency, providing evidence of limits for such changes. The growing evidence for limited resource-driven changes in RADs and evenness further emphasizes the potential importance of temporally variable disequilibria in understanding why communities have certain basic attributes.
Extended cavity perturbation technique to determine the complex permittivity of dielectric materials

An improved measurement technique to determine the complex dielectric properties of materials has been developed that extends the validity of the conventional cavity perturbation technique for circular cylindrical rod-shaped samples in circular cylindrical cavities resonating in TM/sub 0n0/ modes. The method is particularly useful for the dielectric characterization of fragile, low-loss materials that are difficult to machine to typically required thin dimensions. The method further allows for multi-frequency measurements using higher-order radial modes and somewhat alleviates the very small cavity dimensions typically required by the conventional perturbation technique at higher microwave frequencies. A validity criterion for the extended method is given. Measurements of the complex permittivity of NaCl single crystals are presented, showing excellent agreement with theory. >
Dental paleopathology and agricultural intensification in south Asia: new evidence from Bronze Age Harappa.

Patterns of dental disease among Bronze Age people of the Indus Valley Civilization are currently based on early and incomplete reports by non-specialists. This deficiency precludes accurate diachronic analysis of dental disease and its relationship with increasing agriculturalism in the Indian subcontinent. The objective of this paper is to document prevalence of dental disease at Harappa (2500-2000 B.C.), Punjab Province, Pakistan, comparatively evaluate the Harappan dental pathology profile, and use these data to assess theories regarding the dental health consequences of increasingly intensive agricultural dependence. Pathological conditions of the dentition included in the study are abscesses, ante-mortem tooth loss (AMTL), calculus, caries, hypoplasia, hypercementosis, pulp chamber exposure, and alveolar resorption. The Harappan dentition exhibits a dental pathology profile typical of a population whose subsistence base is agriculture. Dental caries at Harappa are present in 6.8% (n = 751) of the teeth and 43.6% (n = 39) of the more completely preserved dental specimens. The use of a caries correction factor is recommended to permit an estimate of caries induced AMTL in calculating the caries prevalence. All dental lesions are present at higher rates in this Harappan study sample than were reported in previous investigations, and important differences in prevalence of dental disease occur between the genders. Prevalence of dental disease increases in the greater Indus Valley as subsistence becomes more intensive and as food preparation and storage technology becomes more efficient.
A kinematic comparison of single and multijoint pointing movements.

Rapid pointing movements (no accuracy or reaction time requirements) were performed under three conditions which limited motion to the shoulder, elbow or a combination of these two joints. Velocity profiles of the hand's trajectory differed during single and multijoint movements. For the same magnitude of displacement, the hand always had a higher peak velocity, shorter rise time (time to peak velocity) and shorter movement time during single joint movements. However, when the profiles were normalized with respect to amplitude and movement time, no significant differences were observed between these three movement conditions. The velocity profiles of the elbow and/or shoulder were also compared under single and multijoint movement conditions. Analysis of these profiles revealed that the relationships between peak velocity and displacement and between movement time and displacement remained the same at the shoulder joint during single and multijoint movements. In contrast, the elbow joint velocity profiles were significantly affected by movement conditions. These relationships (peak velocity/ displacement and movement time/displacement) changed during multijoint movements and became the same as those observed at the shoulder joint. The shape of the hand velocity profile and its invariance across movement conditions can best be explained by dynamic optimization theory and supports the notion that movement of the hand is of primary importance during rapid pointing. However, the consistency of the shoulder velocity profile and the highly significant relationships between the movement of the elbow and shoulder joints indicates that a subordinate joint planning strategy is also used. The purpose of this strategy is to functionally decrease the available degrees of freedom and to simplify coordination between the moving joints. Thus, the organization of arm movements is hierarchically structured with important, but different contributions being made on both the hand planning and joint planning levels.
Thermal Evaluation of the Effects of Gaps Between Adjacent Roof Insulation Panels

The results of a study comparing double-layer to single-layer roof insulation from a heat transfer standpoint are presented. The study concentrates on the joint or gap between adjacent fiberglass roof insulation panels, but the techniques used are equally applicable to other types of insulation. Although the results are primarily an analytical solution, some verifying empirical data are also presented.
Hexrotor UAV platform enabling dextrous interaction with structures — Preliminary work

A force closure grasp is a term from dexterous manipulation that indicates a grasp that can resist any applied wrench, or force-torque. Force closure grasps are desirable because they can completely immobilize an object or impart an arbitrary wrench to an object. With fixed-base manipulators, determining the degree of force closure of a manipulation system is simplified to determining the degree of force closure of the gripper or end effector. In mobile manipulation, the manipulator base is not fixed to the ground so determining the set of wrenches that can be resisted is not strictly limited to the capabilities of the end effector. But due to the large differences in mass of the mobile base and end effector, it is generally safe to assume the degree of force closure is limited by the end effector and not by the ability of the mobile base to remain motionless. As aerial mobile manipulation has started to become an active area of research, the concept of force closure of the entire manipulation system needs to be considered. Conventional aerial platforms are not able to resist an arbitrary wrench so an end effector carried by such a vehicle will not be able to exhibit force closure. This is true because even current quad rotors lack both the number of degrees of freedom but also independence of the degrees of freedom due to the fact that the force vectors are all parallel. We have developed a hex-rotor system with six independent degrees of freedom providing force closure for a dexterous aerial vehicle for mobile manipulation tasks. The ability of the aerial mobile base to exert an arbitrary wrench coupled with a low degree of freedom manipulator will allow for an agile aerial mobile manipulator with true force closure.
The Effect of Irreversibility on the Capacity of a Turbine Blade Row

If the assumption is made that the process followed by the expansion of a gas in a converging blade row is isentropic, thermodynamic analysis leads to the result that the attainment of maximum mass flow, for a given flow area and predetermined inlet pressure and temperature, occurs when sonic velocity is reached at the throat. If, however, as in practice, the expansion proceeds with internal frictional losses, and if certain common assumptions are made regarding these losses, then, assuming adiabatic flow, thermodynamic analysis shows that the maximum flow will occur at a Mach number less than unity. If this paradox is not noticed, it may lead to an appreciable underestimate of the mass flow passed by a blade row for a given set of inlet conditions. This paper examines the relationship between blade row losses and boundary layer characteristics in an attempt to rationalize the calculation of the capacity of a turbine as modified by irreversibility.
Male and female teachers: Do they treat boys and girls differently?

Forty experienced and inexperienced teachers, 20 male and 20 female, were observed during free play periods in preschool classes. Male teachers gave more favorable comment than female teachers, and also more physical affection. Male teachers also joined the play of the children more than female teachers. Female teachers interacted less than male teachers. Experienced teachers initiated behaviors, directed, gave information, asked and answered questions, and helped the child more than inexperienced teachers. Experienced teachers interacted more with boys and girls when they engaged in feminine-preferred activities, with no difference between male and female teachers in this regard. Inexperienced teachers of both sexes interacted more with boys engaging in masculine-preferred activities and girls engaging in feminine-preferred activities. It was suggested that the male stereotype and the school environment are less congruent than the female stereotype and school, and that experienced teachers encourage children to engage in school-type activities.
A Detailed Study of the Low-Frequency Periodic Behavior of a Dry Friction Oscillator

This work examines the periodic stopping motion present in the low-frequency response of dry friction oscillator, excited harmonically through a base spring. Piecewise linear solution methods are used to compare two simple friction models, to consider the effects of viscous damping, and to illustrate stability considerations. Scaling phenomena, particularly at degenerate frequency ratios, are noted. Finally, experimental results provide a means to assess the effectiveness of the simple friction models in predicting observed motion.
Multiple ligand-based emissions from a platinum(II) terpyridine complex attached to pyrene.

Attaching an electron-rich aryl substituent at the 4‘ position of the trpy ligand in Pt(trpy)Cl+ endows the low-lying excited state with intraligand charge-transfer (ILCT) character, enhances the emission intensity, extends the excited-state lifetime, and inhibits exciplex quenching by Lewis bases. When pyrene is the substituent, the complex exhibits singlet- and triplet-state emission and the lifetime extends to 64 μs in room-temperature dichloromethane solution.
Non-infectious virus induces cytotoxic T lymphocytes and binds to target cells to permit their lysis.

MUCH current interest is focused on the involvement of expressed products of the major histocompatability (H–2) gene complex, especially those associated with the K and D regions of H–2, in inducing cell-mediated immune responses and in permitting recognition and killing by cytoxic thymus-derived lymphocytes (CTL). Observations in many laboratories have led to the generalisation that syngeny between stimulator and target cells at the K and/or D region of H–2 is required for CTL activity to virus-infected cells1–3, minor histocompatibility antigens4, the male H–Y antigen5 and chemically modified syngeneic cells6–9. This study asks three questions related to the geneic restriction of induction and expression of CTL: (1) can non-infectious virus efficiently induce CTL, (2) can non-infectious virus absorbed to target cells render them susceptible to killing by CTL, and (3) can non-infectious virus absorbed onto or chemically linked to cells induce CTL and does using allogeneic or xenogeneic carrier cells affect this induction?
Biosynthesis, processing, and secretion of α-L-fucosidase in lymphoid cells from patients with I-cell disease and pseudo-Hurler polydystrophy

N-Acetylglucosamine 1-phosphotransferase is a key enzyme required for synthesis of the mannose 6-phosphate recognition marker that is used by many newly made acid hydrolases for their transport to lysosomes. It has previously been found that lymphoid cells from patients with I-cell disease and pseudo-Hurler polydystrophy have nearly normal intracellular and intralysosomal activities of several lysosomal acid hydrolases, despite a deficiency of N-acetylglucosamine 1-phosphotransferase. These results suggest that lymphoid cells may provide an important system to investigate alternate mechanisms for targeting newly made acid hydrolases to lysosomes. In the present study, the biosynthesis, processing and secretion of alpha-L-fucosidase in I-cell and pseudo-Hurler lymphoid cells was used as a model system to study the existence of such mechanisms. The level of intracellular alpha-L-fucosidase protein in exponentially growing I-cell or pseudo-Hurler lymphoid cultures was statistically indistinguishable from the mean of 19 control cultures. A 1.5 h [35S]methionine pulse experiment showed that alpha-L-fucosidase is initially synthesized by I-cell, pseudo-Hurler and control cultures as an intracellular form (Mr = 58,000). Companion cultures chased with methionine from 2 to 21 h processed the enzyme to an intracellular form (Mr = 60,000) and an extracellular form (Mr = 62,000). All enzyme forms were glycoproteins with polypeptide chains of Mr 52,000. In control cells incubated with radioactive inorganic phosphate (32Pi), less than 1% of the 32Pi incorporated into alpha-L-fucosidase was associated with carbohydrate chains and greater than 99% with polypeptide chains. In I-cell disease lymphoid cells, the 32Pi incorporated into alpha-L-fucosidase was associated solely with polypeptide chains. A qualitative analysis of phosphorylated residues identified phosphoserine in alpha-L-fucosidase from control and I-cell lymphoid cells. Only alpha-L-fucosidase from control cells contained mannose 6-phosphate. These results are consistent with the proposal that I-cell lymphoid cells may use a mannose 6-phosphate-independent mechanism for routing alpha-L-fucosidase. Additional metabolic labelling experiments demonstrated the presence of 32P-labelled alpha-L-fucosidase in both cells and medium of a control lymphoid culture, but only in cells of an I-cell lymphoid culture. In contrast, alpha-L-fucosidase labelled with [35S]methionine was found in cells and medium of control and I-cell lymphoid cultures. Since phosphoserine was only found to occur in intracellular, but not in extracellular alpha-L-fucosidase of the I-cell culture, we speculate that phosphoserine may be involved in intracellular retention of alpha-L-fucosidase in I-cell lymphoid cells.
Site-directed Mutagenesis Reveals the Essentiality of the Conserved Residues in the Putative Diiron Active Site of the Trypanosome Alternative Oxidase

Trypanosoma brucei possesses a non-cytochrome, salicylhydroxamic acid (SHAM)-sensitive ubiquinol:oxygen oxidoreductase known as trypanosome alternative oxidase (TAO). TAO and similar SHAM-sensitive alternative oxidases (AOXs) contain 2-3 conserved diiron-binding motifs (EXXH). Site-directed mutagenesis of residues H165A, E214A, E266A, and H269L within the conserved EXXH motif abolished the ability of TAO to complement the heme-deficient Escherichia coli strain GE1387. These mutations also reduced the growth of this E. coli auxotroph to about 85% of the control cells containing wild type TAO. In contrast, mutation of residues outside the EXXH motifs, e.g. V205A, L243A, C261A, and V271A, had little effect on complementation, and the reduction in the cell growth was about 5-10%. Mutations of the putative iron-binding residues within the EXXH motifs of TAO abolished the ability to confer SHAM-sensitive respiration to E. coli heme mutant, whereas mutations of the non-conserved/non-iron binding residues resulted in 20-30% reduction of SHAM-sensitive respiration of the E. coli auxotroph. Immunoblot analysis of the total cellular protein of transformed E. coli revealed that the expression level of mutated and wild type TAO (35 kDa) remained unaltered. Mutation at C261A produced a truncated but functional protein of 28 kDa. The addition of ortho-phenanthroline to the growth medium produces a non-functional TAO. The effect of ortho-phenanthroline on the activity of TAO was completely alleviated by the addition of iron in the medium, which suggests that iron is needed for the activity of TAO. This work demonstrates that His-165, Glu-214, Glu-266, and His-269 and the presence of iron are essential for the activity of TAO.
NONDESTRUCTIVE MEASUREMENT of TRANSIENT MOISTURE PROFILES and the MOISTURE DIFFUSION COEFFICIENT IN A POTATO DURING DRYING and ABSORPTION BY NMR IMAGING

A nondestructive method to measure the internal moisture distribution and to determine the effective moisture diffusion coefficient for a potato during drying and absorption was developed using NMR imaging and numerical modeling techniques. the coefficients obtained were 1.04 to 7.28 × 10−10 m2/s, for moisture contents between 40% and 55% (wb), during drying with a sample temperature of 40°C; and were 9.78 × 10−12 to 2.33 × 10−11 m2/s, for moisture contents between 56% and 60%, during absorption at 23°C.
Multiple-ionization channels in proton-atom collisions

A detailed investigation of multiple ionization of He (ionization charge states q = 1,2), Ne (q = 1--3), and Ar and Kr (q = 1--4) is presented for proton impact energies ranging from 10 keV to a few MeV. Absolute cross sections for various ionization pathways have been obtained by combining some new measurements with previously published experimental results and, in certain cases, with existing theoretical information. It is shown how each of these pathways contribute to the various stages of target ionization that are observed after the collision and how these experimentally measured quantities are related to the cross sections for initial inner- and outer-shell vacancy production. Areas where additional data are required or where the existing data are not internally consistent are pointed out. In general, it is shown that the existing data are sufficient to describe the ionization of helium as well as the lower levels of ionization of neon, argon, and krypton. However, for the higher degrees of ionization, particularly for Kr, our understanding is hampered by substantial gaps in the available inner-shell ionization data: both in cross-section and branching-ratio information. Nevertheless, the data are sufficient to indicate the relative importance of the various pathways. Formore » all targets, direct multiple outer-shell cross sections were extracted. Analyzing the energy dependences of these cross sections provided some hints as to how to calculate multiple-ionization cross sections, e.g., information as to where the multiple ionization is dominated by the first-order or by a higher-order term in the perturbation expansion of the proton-target interaction is obtained.« less
Ultrasound-guided suprapubic cystostomy catheter placement in the emergency department

Abstract T he purpose of this article is to describe a series of patients undergoing ultrasound-guided suprapubic cystostomy catheter placement in the Emergency Department. A series of 17 consecutive patients who underwent emergent real-time ultrasound-guided suprapubic cystostomy in the ED over a 2-year period is reported. The procedure was facilitated by direct ultrasound imaging of the bladder using a Digital Sonoace 5500 machine. Procedural notes and follow-up records were analyzed for efficacy, safety, and complications. The results demonstrated that trans-abdominal ultrasound confirmed urinary retention before drainage in each of the 17 cases enrolled. Each patient required emergent suprapubic cystostomy catheter placement for acute urinary outflow obstruction because urethral bladder catheterization was not possible or was contraindicated. Continuous real-time ultrasound-guided percutaneous suprapubic cystostomy placement and decompression of the bladder was successful in all 17 (100%, 90–100% CI: 95%) cases. There were no complications reported. In conclusion, real-time ultrasound imaging of the bladder was successful for the purpose of aiding the guidance of a suprapubic cystostomy catheter placement in the ED and might represent an improvement from the standard blind method presently used.
Targeted Metabolomics Connects Thioredoxin-interacting Protein (TXNIP) to Mitochondrial Fuel Selection and Regulation of Specific Oxidoreductase Enzymes in Skeletal Muscle

Thioredoxin-interacting protein (TXNIP) is an α-arrestin family member involved in redox sensing and metabolic control. Growing evidence links TXNIP to mitochondrial function, but the molecular nature of this relationship has remained poorly defined. Herein, we employed targeted metabolomics and comprehensive bioenergetic analyses to evaluate oxidative metabolism and respiratory kinetics in mouse models of total body (TKO) and skeletal muscle-specific (TXNIPSKM−/−) Txnip deficiency. Compared with littermate controls, both TKO and TXNIPSKM−/− mice had reduced exercise tolerance in association with muscle-specific impairments in substrate oxidation. Oxidative insufficiencies in TXNIP null muscles were not due to perturbations in mitochondrial mass, the electron transport chain, or emission of reactive oxygen species. Instead, metabolic profiling analyses led to the discovery that TXNIP deficiency causes marked deficits in enzymes required for catabolism of branched chain amino acids, ketones, and lactate, along with more modest reductions in enzymes of β-oxidation and the tricarboxylic acid cycle. The decrements in enzyme activity were accompanied by comparable deficits in protein abundance without changes in mRNA expression, implying dysregulation of protein synthesis or stability. Considering that TXNIP expression increases in response to starvation, diabetes, and exercise, these findings point to a novel role for TXNIP in coordinating mitochondrial fuel switching in response to nutrient availability.
Genetic Changes in Regulation Occurring in the Tryptophan Biosynthetic Pathway of l-Tryptophan Producing Mutants Derived from Bacillus subtilis K

The regulatory mechanism for l-tryptophan (l-Trp) synthesis was compared between the wild type strain and l-Trp producing mutants of B. subtilis K. In the wild type strain, indolmycin (IM) repressed the synthesis of anthranilate synthetase (AS) more strongly than 5-fluorotryptophan ► (5FT), which repressed AS to the same extent as l-Trp did. 5FT inhibited the activity of AS as strongly as l-Trp did, while IM had no inhibitory effect. In the 5FT resistant strains, the syntheses of AS and tryptophan synthetase (TS-B) were markedly increased by genetic derepression, while AS remained still sensitive to the feedback inhibition by l-Trp. The facts that IM repressed the syntheses of AS and TS-B in the strain which was 5FTr and IMS, and did not repress those in the IM-resistant mutant suggested that IM acts as a co-repressor in a different way from 5FT.
Micro-social structural approaches to HIV prevention: a social ecological perspective

To be effective and sustainable, HIV-prevention interventions need to be sufficiently powerful to counteract prevailing social norms and diffuse through the targeted community to provide social reinforcement for behaviour change. Social structural and environmental factors are major influences on HIV-related behaviours yet the dearth of conceptualization and operationalization of these factors impede progress in intervention development. In this paper we propose a social ecological perspective to intervention and highlight relevant theories from social psychology and organizational behaviour literatures. We examine social networks and social settings as micro-structural and environmental influences on HIV risk behaviours, social identities and norms, and as important targets for HIV-prevention intervention. Intervention approaches are proposed that target networks and behavioural settings and provide participants with socially meaningful and rewarding behavioural options that are consistent with valued prosocial identities or roles. Examples are presented on how such an approach has been utilized in prior HIV prevention interventions, including our social network-oriented intervention that trained disadvantaged former and current illicit drug users to conduct peer outreach. We describe how behavioural interventions may enhance or introduce new prosocial identities and social roles, and that network members may confer social approval to reinforce these identities and roles, leading to sustained behavioural risk reduction and changes in risk behaviour norms.
Measuring coral reef community metabolism using new benthic chamber technology

Accurate measurement of coral reef community metabolism is a necessity for process monitoring and in situ experimentation on coral reef health. Traditional methodologies used for these measurements are effective but limited by location and scale constraints. We present field trial results for a new benthic chamber system called the Submersible Habitat for Analyzing Reef Quality (SHARQ). This large, portable incubation system enables in situ measurement and experimentation on community-scale metabolism. Rates of photosynthesis, respiration, and calcification were measured using the SHARQ for a variety of coral reef substrate types on the reef flat of South Molokai, Hawaii, and in Biscayne National Park, Florida. Values for daily gross production, 24-h respiration, and net calcification ranged from 0.26 to 6.45 g O2 m−2 day−1, 1.96 to 8.10 g O2 m−2 24 h−1, and 0.02 to 2.0 g CaCO3 m−2 day−1, respectively, for all substrate types. Field trials indicate that the SHARQ incubation chamber is an effective tool for in situ isolation of a water mass over a variety of benthic substrate types for process monitoring, experimentation, and other applications.
Ethics for Studying Online Sociotechnical Systems in a Big Data World

The evolution of social technology and research methods present ongoing challenges to studying people online. Recent high-profile cases have prompted discussion among both the research community and the general public about the ethical implications of researching humans, their information, and their activities in large-scale digital contexts. Examples of scientific and market research involving Facebook users and OKCupid clients exemplify the ethical complexities of both studying and manipulating online user behavior. When does data science become human subjects research, and what are our obligations to these subjects as researchers' Drawing from previous work around the ethics of digital research, one goal of this workshop is to work towards a set of guiding principles for CSCW scholars doing research online.
Fracture and distant migration of the Bard Recovery filter: a retrospective review of 363 implantations for potentially life-threatening complications.

Abstract Purpose To report the occurrence of fracture of the Recovery filter and incidence of potentially life-threatening complications associated with fractured fragment migration. Materials and Methods A retrospective study of images obtained after placement of Recovery inferior vena cava (IVC) filters from 2003 to 2006 was conducted at a single tertiary-care center. Images were reevaluated for fracture and migration; complications related to filter fracture were investigated. Kaplan–Meier survival analysis was performed to investigate the relationship between time in situ and fracture. Results A total of 363 Recovery filters were placed; 97 were retrieved, leaving 266 filters in situ (135 patients subsequently died of other causes). The following images were evaluated: 130 chest computed tomography (CT) scans, 153 abdominal CT scans, 254 chest radiographs, 148 radiographs of the abdomen/pelvis, and 106 cavagrams. Mean imaging follow-up interval was 18.4 months (maximum, 81.3 mo). No en bloc migration occurred outside the IVC. Twenty-six limb fractures (all short limbs) were identified in 20 patients; the earliest occurred at 4.1 months. Eight fragment migrations occurred into pulmonary arteries, seven into iliac/femoral veins, one into the right ventricle, and one into the renal vein. Seven fragments were intracaval near the filter, one was extracaval, and one could not be located. Kaplan–Meier survival estimates predicted a fracture rate of 40% at 5.5 years. Of the 20 patients with filter fractures, three died of unrelated causes and 17 remain asymptomatic. Conclusions Recovery filter fractures occurred at the short limb only, with a suggested 5.5-year fracture risk of 40%. No life-threatening events occurred in patients with filter fracture.
Density-dependent dynamics in size-structured plant populations

Year-to-year changes in numbers of individuals in a plant community occur in response to a confluence of factors—nutrient and water availability, climatic conditions, and the type and status of individual plants. Since effects of these factors are conditioned by plant density, we wish to examine the dynamical changes in the composition of a plant community that can be explained, or at least simulated, by a model driven by density alone. We develop a model of plants classified by size or life-state in which each density vector is generated from that of the preceding time period by an appropriate matrix multiplication. Matrix models have been generally discussed by Caswell. In our formulation, matrix entries representing survival and reproduction rates are determined in each time period as implicit or explicit functions of density. This temporal plasticity in life history “parameters” produces an interaction between individual plant histories and community development. We develop a joint analysis of how plants may allocate energy among reproduction, maintenance, and growth so as to maximize “fitness”, and of the long-term dynamics of communities that contain such plants. Density affects plant access to water and to required nutrients, as well as to energy. We shall, however, focus on the latter. In this paper, we emphasize intra- or interspecific competition among perennials, though we sketch out an approach for annuals. Our discussion concerns the model itself, together with some indication, both theoretical and via computer simulations, of the possible dynamical behaviors of the system. (For instance, a species of pioneer type in which all individuals are of the same size will tend to maximize fitness at high density by devoting all energy to maintenance, and none to reproduction. At low density the optimal allocation typically is reversed, and involves either reproduction only, or a mixture of reproduction and maintenance.) Subsequent papers will enlarge on the implications of the model, and will deal more fully with populations of annuals.
Pretreatment with n-6 PUFA protects against subsequent high fat diet induced atherosclerosis-Potential role of oxidative stress-induced antioxidant defense

Abstract Objectives Recent evidence suggests that oxidative stress can promote antioxidant defense and thus be athero-protective. n-6 polyunsaturated fatty acids (n-6 PUFA) are more prone to oxidation, compared to monounsaturated fatty acids (MUFA) and yet have proven anti-atherosclerotic effects. In this study, we tested whether early exposure to a diet rich in n-6 PUFA, compared to a MUFA rich diet would reduce lesion burden, even with subsequent exposure to a high fat, high cholesterol diet (HF). Further, we tested to determine whether oxidative mechanisms are involved in such protection. Methods and results Twenty four, 4 week old, male, LDL receptor knockout (LDL-R −/− ) mice were divided into two groups and fed either a n-6 PUFA rich or a MUFA rich diet for a period of 12 weeks. At this point, 4 mice from each group were euthanized and the remaining 8 mice from each group were fed a HF diet for four weeks. Atherosclerotic lesions, plasma lipids, autoantibodies to lipid peroxide modified proteins, isoprostanes and aortic catalase levels were measured. The n-6 PUFA diet reduced aortic lesions and plasma lipids compared to the MUFA diet and this reduction in lesions continued even after the mice were switched over to the HF diet, despite the fact that the plasma lipids were similar in both groups after the HF diet. n-6 PUFA fed mice had highest plasma isoprostane levels, indicating oxidative stress, but also had higher levels of aortic catalase. On the other hand, MUFA fed mice had comparatively lower levels of isoprostanes and their aortic catalase levels remained low. Finally, aortic lesions were negatively correlated with isoprostanes and catalase. Conclusion An initial exposure to a n-6 PUFA rich diet compared to a MUFA rich diet reduces atherosclerotic lesions and this protection probably involves oxidative stress induced by PUFA.
Basis function calculations for the massive Schwinger model in the light-front Tamm-Dancoff approximation

Abstract We use light-front field theory to study the massive Schwinger model. After making a Tamm-Dancoff truncation of Fock space so that no more than four particles are allowed in any state, the coupled light-front Tamm-Dancoff integral equations for charge zero states are solved by expanding the two-particle and four-particle amplitudes in a finite basis, thereby converting the original equations into a simple matrix equation. By retaining the four-particle sector we are able to study both the lowest energy boson of the theory and the first excited state, which for massless fermions is a scattering state of two ground state bosons. Known results for the massless Schwinger model are accurately reproduced with reasonably small bases, and existing numerical results for the massive model are reproduced and improved. The rich physics of the Schwinger model is used to elucidate several simple problems in the use of basis functions to solve Hamiltonian field theories.
PC bond cleavage of (silox)3NbPMe3 (silox = tBu3SiO) under dihydrogen leads to (silox)3Nb=CH2, (silox)3Nb=PH or (silox)3NbP(H)Nb(silox)3, and CH4.

Photolysis of the equilibrium mixture (silox)3NbPMe3 (1) + H2 (1−3 atm) ⇄ (silox)3Nb(Heq)2 (2e, tbp)/(silox)3Nb(Ht)2 (2t, pseudo-Td) + PMe3 causes PC bond cleavage. Depending on conditions, various amounts of (silox)3NbCH2 (3), (silox)3NbPH (5-H), (silox)3NbPMe (5-Me), (silox)3NbP(H)Nb(silox)3 (9, precipitated if N2 is present; X-ray), (silox)3NbH (4, active only through equilibration with 2e,t), and CH4 are produced. Addition of PH3 to 1 provides an independent route to 5-H; its deprotonation gives [(silox)3NbP]Li (6), whose methylation yields 5-Me. Early conversion 3:5-H ratios of ∼3:1 suggest that initial PC bond activation is slow relative to subsequent PC bond cleavages. Addition of HPMe2 and H2PMe to 1 generates (silox)3HNbPMe2 (7) and (silox)3HNbPHMe (8), respectively, and both degrade faster than PMe3. A mechanism based around sequential PC or CH oxidative addition, followed by 1,2-elimination events, is proposed. The limiting step in the decomposition of all PMe3 is a slow hydrogenation of 3 to r...
Formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxo-dGuo) by PAH o-quinones: involvement of reactive oxygen species and copper(II)/copper(I) redox cycling.

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants and procarcinogens that require activation by host metabolism. Metabolic activation of PAHs by Aldo-Keto-Reductases (AKRs) leads to formation of reactive and redox active o-quinones, which may cause oxidatively generated DNA damage. Spectrophotometric assays showed that NADPH caused PAH o-quinones to enter futile redox-cycles, which result in the depletion of excess cofactor. Copper (II) amplified NADPH-dependent redox-cycling of the o-quinones. Concurrent with NADPH oxidation, molecular oxygen was consumed, indicating the production of ROS. To determine whether PAH o-quinones can cause 8-oxo-dGuo formation in salmon testis DNA, three pre-requisite experimental conditions were satisfied. Quantitative complete enzymatic hydrolysis of DNA was achieved, adventitious oxidation of dGuo was eliminated by the use of chelex and desferal, and basal levels of less than 2.0 8-oxo-dGuo/105 dGuo were obtained. The HPLC-ECD analytical method was validated by spiking the DNA with standard 8-oxo-dGuo and demonstrating quantitative recovery. HPLC-ECD analysis revealed that in the presence of NADPH and Cu(II), submicromolar concentrations of PAH o-quinones generated > 60.0 8-oxo-dGuo adducts/105 dGuo. The rank order of 8-oxo-dGuo generated in isolated DNA was NP-1,2-dione > BA-3,4-dione > 7,12-DMBA-3,4-dione > BP-7,8-dione. The formation of 8-oxo-dGuo by PAH o-quinones was concentration-dependent. It was completely or partially inhibited when catalase, tiron or a Cu(I) specific chelator, bathocuproine were added, indicating the requirement for H2O2, O2− and Cu(I), respectively. Methional which is a copper-hydroperoxo complex (Cu(I)OOH) scavenger also suppressed 8-oxo-dGuo formation. By contrast, mannitol, sodium benzoate and sodium formate, which act as hydroxyl radical scavengers, did not block its formation. Sodium azide which can act as both a hydroxyl radical and 1O2 scavenger abolished the formation of 8-oxo-dGuo. These data showed that the production of 8-oxo-dGuo was dependent on Cu(II) /Cu(I) catalyzed redox cycling of PAH o-quinones to produce ROS and that the immediate oxidant was not hydroxyl radical or Cu(I)OOH and that it is more likely 1O2 which can produce a 4,8-endoperoxide-dGuo intermediate.
Effects of endotoxaemia and carbohydrate overload on glucose and insulin dynamics and the development of laminitis in horses.

Summary Reasons for performing study: Insulin resistance (IR) is a risk factor for pasture-associated laminitis in equids and alimentary carbohydrate overload may trigger laminitis. Whether glucose metabolism responses to carbohydrate overload are more pronounced in insulin-resistant horses requires further study. Hypothesis: Horses pretreated with endotoxin to alter insulin sensitivity differ significantly in their glucose and insulin responses to carbohydrate overload. Methods: Horses (n = 24) were divided into 3 groups. A lipopolysaccharide (LPS; n = 8) group that received endotoxin as an 8 h 7.5 ng/kg bwt/h i.v. continuous rate infusion, an oligofructose (OF; n = 8) group that received an infusion of saline followed by 5 g/kg bwt OF via nasogastric intubation, and a LPS/OF (n = 8) group that received LPS followed 16 h later by OF. Glucose and insulin dynamics were evaluated at -24 h and 48 h using the frequently sampled i.v. glucose tolerance test and minimal model analysis. Physical examinations and haematology were performed and the severity of laminitis assessed. Results: Horses receiving LPS developed leucopenia and both LPS and OF induced clinical signs consistent with systemic inflammation. Insulin sensitivity significantly decreased (P<0.001) over time, but responses did not differ significantly among groups. Time (P<0.001) and treatment × time (P = 0.038) effects were detected for the acute insulin response to glucose, with mean values significantly increasing in LPS and LPS/OF groups, but not the OF group. Five horses in the LPS/OF group developed clinical laminitis compared with 0 and 2 horses in the LPS and OF groups, respectively. Conclusions: Endotoxaemia and carbohydrate overload reduce insulin sensitivity in horses. Endotoxin pretreatment does not affect the alterations in glucose metabolism induced by carbohydrate overload. Potential relevance: Insulin sensitivity decreases after carbohydrate overload in horses, which may be relevant to the development of pasture-associated laminitis.
Epidemiologists try many ways to show that physical activity is good for seniors' health and longevity. Review of special issue of Journal of Aging and Physical Activity: The Evergreen Project.

The April, 1998, issue of the Journal of Aging and Physical Activity (vol.6, no.2) is devoted entirely to reports of research from "The Evergreen Project," an ongoing multidisciplinary, longitudinal study of physical activity, health, and functioning in the population of elderly adults in Jyvaskyla, Finland. The issue contains an descriptive overview of the Project by Eino Heikkinen (Background, design, and methods of the Evergreen Project, pp. 106-120) and reports of five interdisciplinary studies of the levels of physical activity in the elderly and various outcomes related to it. In addition to the original, peer-reviewed reports, the issue contains abstracts of 13 studies from the Evergreen Project published in other journals and a bibliography of English language reports associated with the project. The present review concerns the five interdisciplinary studies presented in the special issue.
Tidal analysis experiments with sun-synchronous satellite altimeter data

The ERS-1, ERS-2 and Envisat series of satellite altimeters provide the only extensive datasets that could conceivably be usedto constrain ocean tide models in high latitudes. Their sun-synchronous sampling, however, severely limits theobservations of solar tides, especially the principal semidiurnal S2 constituent. The Munk–Cartwright response method is anatural choice when attempting to analyze sun-synchronous data. The present study examines various ways a response analysis might be implemented to extract tides from ERS data. Admittances expressed as simple linear or constant functions of frequency cansometimes improve estimates over standard parameterizations, especially if done in conjunction with a reasonably accurate priorsolution. Some form of regularization, such as ridge regression, is also shown to improve the estimates. The approach provesbeneficial in a test for the southern Indian Ocean tides. It offers some promise for regions otherwise void of usefulobservations.
Pharmacodynamics and pharmacokinetics of ciprofloxacin during sustained low-efficiency dialysis

Little information is available regarding ciprofloxacin pharmacokinetics and pharmacodynamics in sepsis patients receiving sustained low-efficiency dialysis (SLED). This study determined the pharmacokinetics and simulated pharmacodynamics of ciprofloxacin in ICU patients during SLED.