cssi/SciSciGPT-SciSciNet huggingface dataset:
Nonrandom mixing models of HIV transmission

Models of HIV transmission and the AIDS epidemic generally assume random mixing among those infected with HIV and those who are not. For sexually transmitted HIV, this implies that individuals select sex partners without regard to attributes such as familiarity, attractiveness, or risk of infection. This paper formulates a model for examining the impact of nonrandom mixing on HIV transmission. We present threshold conditions that determine when HIV epidemics can occur within the framework of this model. Nonrandom mixing is introduced by assuming that sexually active individuals select sex partners to minimize the risk of infection. In addition to variability in risky sex rates, some versions of our model allow for error (or noise) in information exchanged between prospective partners. We investigate several models including random partner selection (or proportionate mixing), segregation of the population by risky sex rates, a probabilistic combination of segregation and random selection induced by imperfect information (or preferred mixing), and a model of costly search with perfect information. We develop examples which show that nonrandom mixing can lead to epidemics that are more severe or less severe than random mixing. For reasonable parameter choices describing the AIDS epidemic, however, the results suggest that random mixing models overstate the number of HIV infections that will occur.
A synchronous homopolar machine for high-speed applications

The design, construction, and test of a high-speed synchronous homopolar motor/alternator, and its associated high efficiency six-step inverter drive for a flywheel energy storage system are presented in this paper. The work is presented as an integrated design of motor, drive, and controller. The performance goal is for power output of 30 kW at speeds from 50 kRPM to 100 kRPM. The machine features low rotor losses, high efficiency, construction from robust and low cost materials, and a rotor that also serves as the energy storage rotor for the flywheel system. The six-step inverter drive strategy maximizes inverter efficiency, and the sensorless controller works without position or flux estimation. A prototype of the flywheel system has been constructed, and experimental results for the system are presented.
The sugar industry in Peru

Since the early Colonial times sugar production has been a key sector in the Peruvian export economy. This article analyzes its evolution as from the beginning of its modern phase by mid 19th Century, its consolidation in the Northern coastal region, and its concentration in scale-economy plants. The prosperity of this type of production contributed to the formation of both an oligarchy which governed the country until 1968, and the populist party (APRA) and its electoral basis (the so-called «Aprista North»). In the sixties Velasco Alvarado’s military revolution nationalized the sugar industry, which underwent structural changes leading to a serious crisis in the eighties that has not been overcome up-todate.
The Ruptured Supervisory Alliance and Its Repair: On Supervisor Apology as a Reparative Intervention

In what ways do supervisors repair the ruptured supervisory alliance? In this article, that question is considered, with focus given to one rupture repair intervention: Supervisor apology. Apology/forgiveness theory and research are integrated with current thinking about supervision alliance rupture and repair. Using the recent conflict transformation research of Kirchhoff and colleagues (Kirchhoff, Strack, & Jager, 2009; Kirchhoff, Wagner, & Strack, 2012) as a building block, the 10 elements of apology are examined vis-a-vis the supervisory situation, and the applicability of the concepts of simple and complete apology for supervision alliance rupture repair are presented. Eight statements that link apology and forgiveness with supervision alliance rupture and repair conceptualization are proposed, and a case example that communicates the reparative effectiveness of supervisor apology is described. Supervisor rupture identification and repair is viewed as being an important competency that involves a sup...
Fast winner determination for agent coordination with SBB auctions

The runtime of winner determination for each round of a sequential bundle-bid auction (= SBB auction) has recently been shown to be linear in the number of submitted bids, which makes SBB auctions appealing for solving cooperative task-assignment problems. In this paper, we introduce the Shrewd (= SHrewd Resource Efficient Winner Determination) algorithm, whose runtime is linear in the number of submitted bids but typically much smaller than the runtime of the existing winner-determination algorithm for SBB auctions, making them feasible for larger bundle sizes.
Natural and artificial flying machines

The advent of fossil-fuel engines has provided aeronautical engineers with a ten-fold to hundred-fold increase in power-to-gross-weight ratios over the ratios available for biologically-powered flight creations, such as birds and human-powered aircraft. The tremendous achievements of engine-powered aircraft over the past eight decades have tended to obscure the fact that numerous flight problems had already been elegantly solved by birds many tens of millions of years ago. Recent projects in human-powered aircraft, in bird aerodynamics, and in the development of a flying replica of a 11-m span pterodactyl have introduced us to the bird-airplane interface. The result has been an increasing respect for “Mother Nature the Engineer,” who derived efficient evolutionary solutions for all of the factors involved in biological flight. Engineers and scientists also have much to learn from nature regarding aeroelasticity as a factor in tailoring structures to the varied demands of flight, including active-control technology, boundary-layer control, and navigation.
Incorporation of lead phthalocyanine into periodic nanolayered assemblies for advanced optical systems

Periodically structured polymeric materials can lead to the next generation of electro-optic and nonlinear optical devices for applications in information technology. Layer-multiplying melt coextrusion is an attractive method for fabricating periodic structures with thousands of alter- nating polymer microlayers or nanolayers. Many advanced applications for periodic polymeric structures would be enabled by locating a photoactive dye in one or both layers. However, it is anticipated that due to the thinness of the individual layers and the relatively low molecular weight of many dyes, a substantial fraction of the dye will diffuse from the doped layers into the undoped layers during melt coex- trusion. In the present study, we demonstrate two methods for confining the activity of a photoactive dye, lead phthalo- cyanine, to the doped layers. Polycarbonate containing lead phthalocyanine was coextruded with undoped polyester as an assembly of 128 alternating 86 nm-thick layers. Using the absorption spectra, we demonstrated that a high concentra- tion of the monomer form persisted in the polycarbonate layers, whereas the lead form was converted to the less active lead-free form in the polyester layers. Thus, the active monomer form of PbPc(b-CP)4 was maintained selectively in the polycarbonate layers. In the second approach, the coex- trusion process was altered so that the alternating polycar- bonate and polyester layers were separated by a thin layer of a barrier polymer. The barrier layer prevented diffusion of the dye during melt coextrusion and the dye remained selec- tively in the polycarbonate layers. V C 2009 Wiley Periodicals, Inc. J Appl Polym Sci 113: 2150-2159, 2009
An improved push-pull voltage fed converter using a tapped output-filter inductor

A new concept of using a tapped output-filter inductor and an auxiliary commutating diode to reduce the liklihood of transformer core saturation in a push-pull, voltage-fed converter is presented. The linearized circuit model and transfer functions are derived with a hybrid approach using both state-space and circuit averaging. Operation of the new converter—including parasitic effects—is discussed, and a design equation for inductor tap ratio is established. It is predicted and experimentally confirmed that the new converter has more symmetrical transformer core operation, and the potential exists for lower transistor turnon current and reduced transistor voltage stress. These benefits reduce switching loss and enhance transistor reliability.
Microlithographic lens for DUV scanner

This paper describes several kinds of new technologies introduced into the latest microlithographic lens system for Nikon’s DUV (Deep Ultra Violet) scanner.
Nonlinear time-domain performance model for a wave energy converter in three dimensions

A nonlinear three-dimensional time-domain performance model has been developed for a floating axisymmetric point absorbing WEC. This model employs a set of linear partial differential equations, in the form of a state-space model, to replace the convolution integrals needed to solve for radiation reaction. Linear time-domain results are verified against predictions from a frequency-domain model. Nonlinear timedomain predictions are compared back to frequency-domain and linear time-domain predictions to show the effects of some linearization assumptions. A simple resistive control strategy is applied throughout these scenarios.
The impact of forest cutting on the diversity of ground beetles ( Coleoptera: Carabidae) in the southern Appalachians.

. 1. Carabid beetles were sampled by means of pitfall traps on several clearcut areas and in adjacent forests. 2. A hierarchical analysis of diversity revealed a significant increase in the within-genus component of species diversity after forest cutting. 3. This trend in intrageneric diversity was obscured, with respect to total species diversity, by a nonsignificant reduction in diversity at the generic level. 4. The increase in the within-genus component of species diversity following forest cutting was consistent with the hypothesis that disturbance of a cornmunity can disrupt processes of competitive exclusion.
Renormalization and fixed points in finance, since 1962

Abstract In diverse sciences that lack Hamiltonians, the analysis of complex systems is helped by the powerful tools provided by renormalization, fixed points and scaling. As one example, an intrinsic form of exact renormalizability was long used by the author in economics and related fields, most notably in finance. In 1962–3, its use led to a model of price variation founded on the (Cauchy-Polya-Levy) stable distribution, with striking data collapse that accounted for observed large deviations from Gaussianity. In 1965, a different form of exact renormalization led to fractional Brownian motion, which neglected large deviations but accounted for long dependence and the resulting non periodic cyclic behavior. Finally, from a seed planted in 1972, exact renormalizability and scaling led to a model of price variation of which the M1963 and M1965 models are special examples. This broader model, fractional Brownian motion in multifractal time, accounts simultaneously for both large deviations and long dependence. These three steps are in loose parallelism with space, time and joint renormalization in statistical physics. This presentation surveys the old works and many new developments described in the author's 1997 books on fractals and scaling in finance.
High-temperature strain relaxation in silica by optical correlation spectroscopy

Abstract Strain relaxation has been studied in silica glass from the glass transition up to 1750°C by means of optical correlation spectroscopy. The decay function shape for longitudinal strain is found to be independent of temperature so that silica can be considered thermorheologically simple over a large part of its transformation region. Measurements on high silica glass (Corning Code 7900) yield the same decay function apart from a viscosity-dependent shift of the average relaxation time.
The Relationship Between Parents’ Anti-fat Attitudes and Restrictive Feeding

Objective: Anti-fat prejudice is a common attitude in our society, and it has implications for those who hold and are targets of this prejudice. Little is known, however, about how parents’ anti-fat attitudes impact the ways they feed their young children. We hypothesized that parents’ attitudes about weight would predict parents’ restrictive feeding practices above and beyond the effects of the child's actual weight and the parents’ concern about child overweight. Research Methods and Procedures: A total of 126 mothers and 102 fathers returned surveys about anti-fat attitudes, feeding practices (restriction for weight and restriction for health), and concern about child overweight. Results: Parental concern about child overweight was related to higher restrictive feeding practices for both mothers and fathers. Parents’ anti-fat attitudes also predicted restrictive feeding above and beyond the effects of parent and child BMI and parental concern about overweight. Discussion: These findings suggest that parents’ anti-fat attitudes impact the way they feed their children.
Marrow Fat and Bone: New Insights from Mice and Humans

Adipocytes are an essential component of the bone marrow micro-environment. Developmentally, fatty infiltration of the marrow in the appendicular skeleton occurs at the time of peak bone acquisition. Conversely, vertebral marrow fat is most predominant with advancing age. Recent studies suggest that the amount of marrow fat is inversely associated with bone mineral density. It may also be a predictor of subsequent fracture. The molecular cellular and genetic aspects of marrow fat in mouse models and humans are discussed. More studies are needed to understand the relationship of marrow fat to mineral metabolism, energy balance, and skeletal fragility.
Growth and nutrient uptake potential of Azolla caroliniana willd. and Salvinia rotundifolia willd. as a function of temperature

Abstract Growth and nutrient uptake of Azolla caroliniana Willd. and Salvinia rotundifolia Willd. were studied under controlled conditions at constant temperatures ranging from 10 to 30°C. Maximum plant density (standing crop) occurred in the 15–20°C range, with Azolla and Salvinia attaining densities of 158 and 270 g (dry wt) m −2 , respectively. Net primary productivity was greatest within the range of 20–30°C (5.3 and 13.2 g (dry wt) m −2 day −1 for Azolla and Salvinia , respectively). Maximum productivity was found to occur at intermediate plant-density levels. Specific growth rate (SGR) of Azolla ranged from 0.063 to 0.142 days −1 at 10° and 30°C, respectively, while the SGR of Salvinia was in the range 0.047–0.112 days −1 at 10° and 25°C, respectively. Nutrient removal rates in Azolla and Salvinia cultures were greatest at 20°C. Maximum rate of P uptake by Azolla was 21.4 mg m −2 day −1 , while maximum N and P uptake by Salvinia was 127.2 and 26.5 mg m −2 day −1 , respectively.
Release of prostaglandins evoked by neurohormonal stimuli in the isolated spleen of rabbit.

Abstract In the isolated spleen of rabbit perfused with Tyrode solution, sympathetic nerve stimulation (NS) and administration of either noradrenaline (NA), 50–75 ng, or bradykinin (BK), 50 ng, released a material into the venous effluent that cause contraction of rat stomach strip (RSS), rat colon (RC), chick rectum (CR) and bovine coronary artery (BCA). The musculotropic activity of the material released from the spleen was not diminished when it was allowed to stand at either 37°C or at room temperature. The release of this musculotropic material evoked by neurohormonal stimuli was abolished during the infusion of the prostaglandin (PG) synthesis inhibitor, indomethacin, 1 μg/ml. Application of authentic PGE2 directly on the assay organs caused contraction, whereas PGI2 contracted RSS, RC, and CR but relaxed BCA. In the spleen labeled with [14C]AA , NS, NA or BK released radio-labeled products haveing the chromatographic characteristics of PGE2 and, to a lesser extent, of PGF2α. Indomethacin abolished the release of these radiolabeled products from the spleen. These observations taken together with the musculotropic characteristics of the material in the venous effluent, suggest that PGE2 is the major product of cyclo-oxygenase released by NS, NA and by BK from the isolation perfused spleen of rabbit.
Three additional families of Lagrangian surfaces of constant curvature in complex projective plane

Abstract Three additional families of Lagrangian surfaces of constant curvature in complex projective plane C P 2 ( 4 ) shall be added to the list of Theorem 1 in my article [B.-Y. Chen, Classification of Lagrangian surfaces of constant curvature in complex projective planes, J. Geom. Phys. 53 (2005) 428–460].
African American College Students' Preferences for Quick Service Restaurants

ABSTRACT The competition among the quick service restaurants (QSRs) continues to be intense, and college students have a variety of food choices to select. This study investigated the African American students' demographics, food habits, food preferences, and importance of image attributes in selecting and patronizing a QSR. The findings reveal that the four most important image attributes to this group of students seems to be: cleanliness, quality and taste of food/beverage, price/value, and friendly/attentive service. In addition, students' perceptions of selected QSRs and marketing strategies are discussed.
A probability model for the time to fatigue failure of a fibrous composite with local load sharing

Abstract A composite material consisting of stiff, parallel fibers embedded in a flexible bonding matrix is considered. A steady tensile load is applied to the composite, and as time passes, breaks occur at various places along the fibers. Once enough breaks have accumulated in a cross-sectional area of the composite, it fails. This failure process is modeled by viewing the composite as a chain of bundles with the loads from failed fibers being shared in a localized fashion within each bundle. Using this model, approximations to the distribution of the time to failureof the composite are derived. Two types of approximations are considered. One is an approximation to the entire distribution with uniformly small absolute error, and the other is an approximation to the lower tail of the distribution with small relative error. Both approximations are based on the fact that for an appropriate choice of K the time to failure of the bundle is asymptotically equivalent to the time of the first appearance of a set of k or more adjacent failed fibers—a crack of size k—in one of the bundles.
Foaming and emulsifying properties of soy protein isolate and hydrolysates in skin and hair care products

There is a growing market for formulating proteins into a wide variety of products including laundry detergents, bath products, shampoos, and skin cleansers. Soy protein isolate (SPI), soy protein hydrolysate A (SPHA) from papainmodified SPI, and hydrolysate B from papain- and proteasemodified SPI were used in blends with three major detergents, sodium dodecyl sulfate (SDS), sodium laureth sulfate (SLS), and disodium lauryl sulfosuccinate (DSLSS). SPHA was used to partially replace these detergents in bath soap, conditioning shampoo, and cream hand cleanser. The effectiveness of SPI, SPHA, or SPHB blends with the three detergents and their influence in prototype products on foaming and emulsifying properties were investigated.
Characterization of two substance P antisera

The cross reactivity of two currently used substance P (SP) antisera (K 16 and K 25) with various analogues of SP, partial sequences of SP and other naturally occurring peptides were tested in a radioimmunoassay system. Both antisera were found to be C-terminal directed, this tendency being most pronounced for antiserum K 16. The capacity of antiserum K 25 to bind various SP-related peptides correlated to the previously described biological activity of these peptides on the isolated guinea pig ileum. The results thus indicate that this antiserum binds to a biologically active part of the SP-molecule.
Single conformation spectroscopy of a flexible bichromophore: 3-(4-hydroxyphenyl)-N-benzylpropionamide.

Resonant two-photon ionization (R2PI), UV hole-burning (UVHB), and resonant ion-dip infrared (RIDIR) spectroscopy have been used to study the single-conformation infrared and ultraviolet spectroscopy of 3-(4-hydroxyphenyl)-N-benzylpropionamide (HNBPA, HOC6H5CH2CH2(C═O)NHCH2C6H5) cooled in a supersonic expansion. UVHB determines the presence of three conformers, two of which dominate the spectrum. RIDIR spectra in the OH stretch (3600−3700 cm−1), amide NH stretch (3450−3500 cm−1), and C═O stretch (1700−1750 cm−1) regions reveal the presence of small shifts in these fundamentals that are characteristic of the folding of the flexible chain and the ring−ring and ring−chain interactions. On the basis of a comparison of the experimental frequency shifts with calculations, the two major experimentally observed conformers are assigned to two folded structures in which the two aromatic rings are (nominally) face-to-face and perpendicular to one another. The perpendicular structure has a transition assignable to th...
An estimation algorithm for multirate sampled digital control systems

Abstract This paper presents an optimization-based algorithm for state estimation of multirate digital control systems. The algorithm features a predictor estimator structure and it is derived by employing a time invariant modelling approach to multirate systems. Special care is taken to ensure the causality of the derived estimation algorithm and to reduce the dimensionality inherent in multirate system modelling while maintaining a reasonably simple implementation. The proposed algorithm is developed to ensure convergence in state estimation between base sampling instants as well as between model rate sampling instants.
Arab media, corporate communications, and public relations: the case of Al Jazeera

Over the past few decades, public relations has developed significantly in the West into a sophisticated management function which is recognized as an integral part of any organization's attempt to communicate with various persons, both within and outside the organization, in order to achieve its goals and objectives. However, this is not the case in the Arab world where public relations remains underdeveloped and, even when practised, is relatively unsophisticated. This paper deals with the public relations function in a prominent though controversial Arab media organization: Al Jazeera Satellite Channel. It explores how Al Jazeera has been dealing with internal and external communication issues impelled initially by its role as a satellite broadcaster spearheading changes in a vibrant Arab mediascape and subsequently by its expansion into a global broadcaster. Drawing on James Grunig's four models of communication to analyze Al Jazeera's public relations practices, the case study at hand outlines some o...
Surviving Surrogate Decision-Making: What Helps and Hampers the Experience of Making Medical Decisions for Others

BACKGROUND A majority of end-of-life medical decisions are made by surrogate decision-makers who have varying degrees of preparation and comfort with their role. Having a seriously ill family member is stressful for surrogates. Moreover, most clinicians have had little training in working effectively with surrogates.
Differential Inhibition of Prion Propagation by Enantiomers of Quinacrine

Prion diseases are fatal neurologic disorders caused by accumulation of a pathogenic isoform (PrP(Sc)) of the prion protein (PrP). The recent discovery of the inhibitory action of quinacrine on PrP(Sc) formation in scrapie-infected neuroblastoma (ScN2a) cells raised the possibility of a treatment for patients with prion disease. To investigate the efficacy of quinacrine enantiomers, we measured the inhibitory effect of these isomers on PrP(Sc) formation in ScN2a cells. (S)-quinacrine exhibited superior antiprion activity compared with (R)-quinacrine and two generic quinacrines that appear to be racemates. Treatment with these various forms of quinacrine did not induce adverse changes affecting cell survival and the expression of marker proteins over a range of potentially therapeutic concentrations. Thus, quinacrine enantiomers demonstrated stereoselectivity on prion elimination but not cytotoxicity in ScN2a cells. Our results raise the possibility that in vivo treatment using one enantiomer of quinacrine may be superior to a racemic mixture, which is the form that is generally used when quinacrine is employed to treat parasitic diseases.
MCL1 meets its end during mitotic arrest.

Evidence for the destruction of the anti-apoptotic protein MCL1 during prolonged mitotic arrest comes from three papers, one in The EMBO Journal and two in Nature, thus shedding light on the mechanism of apoptosis induction under these conditions.
Applications of thermoanalytical methods to the study of thin films

Studies of the formation and properties of thin films is a growing area in both science and technology. Characterization of these films and the processes by which they are prepared is a major factor in understanding, controlling, and optimizing their synthesis and usefulness. Thermal methods can play an important role in such studies, provided that they can overcome the difficulties imposed by the massive amount of associated substrate. Unless one is studying the film — substrate interaction, the substrate's presence only serves to decrease the sensitivity by diluting or reducing the thermal effect being measured. The three basic strategies that have evolved are discussed and examples described. One approach is to remove the film from the substrate, when this is appropriate and feasible, and then study the film separately. A second method is to use larger samples and careful measurements in an effort to overcome the reduced sensitivity. The final means is to develop very sensitive and/or selective techniques to investigate the film and its potential interactions with the substrate.
Singularity and Autoregressive Disturbances in Linear Logit Models

The implications of including autoregressive disturbances in linear logit models of demand systems are explored. It is argued that the normality assumption of the error terms is more appropriate in the linear logit model than in a share equation model with additive disturbances (commonly found in the literature). Autoregressive disturbances and their implications for model estimation are discussed in that context. Both theoretical arguments and empirical evidence are presented in favor of the logit specification given the presence of serial correlation.
Endocrine influences on parental care during a short breeding season : testosterone and male parental care in Lapland longspurs (Calcarius lapponicus)

In males of socially monogamous birds, plasma testosterone (T) typically declines to low levels during the parental phase. Studies on multiple-brooded species indicate that high T may be incompatible with high-quality paternal care. The length of the breeding season may affect the costs and benefits of high T and its effect on paternal care. We studied the effect of experimentally elevated T on paternal care in a single-brooded species with a short breeding season, the Lapland longspur (Calcarius lapponicus). We monitored T levels and parental behavior in 16 males with subcutaneous T implants, 14 males with empty implants, and 14 unimplanted males. We videotaped nests when nestlings were 2–3 days old and again at 4–5 days. T males with 2- to 3-day-old young visited nests and fed young less often than control males, and the mates of the T males compensated with elevated visits and feedings. However, when nestlings were 4–5 days old, T males visited their nests at normal rates – though feeding movements remained below normal – and T females visited and fed at normal rates. Nestling mass and nest success were similar in both groups. Overall, high T suppresses paternal care in Lapland longspur males. The partial improvement of paternal care when nestlings are older, despite high T, may be related to the short 6-week breeding season of this arctic species, and the consequently reduced benefits of sexual behavior late in the breeding season.
Spectrum Utilization Study in Support of Dynamic Spectrum Access for Public Safety

Radios for public safety communication have some of the most stringent requirements for access, reliability and robustness. While wireless technology has seen tremendous strides in the past decade, large parts of the public safety infrastructure have unfortunately lagged behind. Today the majority of the Land Mobile Radios (LMR) used by police and fire departments, among others, utilize bandwidth inefficient analog FM radio systems, despite the limited available radio spectrum allocated for these applications. Additionally, numerous interoperability issues continue to exist between the various agencies, jurisdictions and disciplines; for example, radios from the state law enforcement authorities may not be able to communicate with Federal ones. This paper presents data from spectral measurements carried out over several public safety bands in the city of Chicago. Occupancy estimates over a period of several months are given and analyzed, and seasonal/event-driven variation and trends are discussed. The results demonstrate an imbalance in occupancy between public safety channels, which show high peak occupancy during normal day to day operations, and adjacent commercial LMR channels, which have much lower usage. This indicates potential opportunities for the application of dynamic spectrum access techniques to increase the capacity of public safety channels during emergencies. Furthermore, the spectrum utilization data may be useful for planning for the expansion or optimization of present-day systems.
The Rhetoric and Iconography of Reform: Women Coal Miners in Belgium, 1840–1914

Reflecting on the development of industrial capitalism in Europe, Antonio Gramsci wrote:It is worth drawing attention to the way in which industrialists…have been concerned with the sexual affairs of their employees and with their family arrangements in general. One should not be misled…by the ‘puritanical’ appearance assumed by this concern. The truth is that the new type of man demanded by the rationalization of production and work cannot be developed until the sexual instinct has been suitably regulated and until it too has been rationalized.
Translating What We Know about the Context of Antisocial Behavior into a Lower Prevalence of Such Behavior.

Although we have identified many variables that affect antisocial behavior, there is no evidence that we have learned how to reduce the incidence of such behavior or the proportion of young people who repeatedly engage in antisocial behavior. It is appropriate, therefore, for behavioral scientists to turn some of their energies to research on reducing the incidence and prevalence of antisocial behavior. Small communities may be a particularly useful social unit in which to conduct experimental research. The interventions to be tested include advocacy and community organizing to influence communities to make validated school and clinical interventions widely available and to assist them in increasing other forms of supervision of young people and social and material support of families. Key components of advocacy and community organizing are suggested, and possibilities for research are described.
Effect of Taxol and Diamide on Shear Tolerance of Hybridoma and Insect Cells

The role of the cytoskeletal structure on the shear tolerance of hybridoma and insect cells to laminar and turbulent shear flow field was investigated. The cytoskeletal network of cells modified by taxol and diamide, which are known to alter the stability of specific cytoskeletal components, resulted in increased cell shear tolerance to both laminar and turbulent flow fields. Plasma membrane fluidity measurements revealed that modification of microtubules by taxol did not alter the fluidity state of the plasma membrane. The increase in shear tolerance by taxol treatment is attributed to its ability to stabilize microtubules in the cytoskeleton. A low concentration of taxol, 0.05 microM, did not reduce the hybridoma cell growth rate or the monoclonal antibody production rate, but both were decreased at a higher concentration, 0.25 microM.
A neural observer for dynamic systems

Abstract A new class of observers is presented to estimate the states of dynamic systems, based on the rapidly growing technology of neural networks. The observer, with its parallel processing capabilities, provides a viable means for constructing, in real time, the states of complex dynamic systems from a small number of sensors. It has also the ability to learn about the system dynamics, generalize from previous learning and abstract essential characteristics from contaminated inputs. Unlike conventional Luenberger observers, where the design calculations are rather intensive and the implementation is a challenge in real time even for low order systems, the design and implementation of the neural observer is very simple and straightforward. It can equally be designed for linear as well as non-linear systems, whereas the Luenberger observer is limited only to linear systems. Numerical examples are presented to illustrate the merits of the proposed neural observer in estimating the states of simple linear and non-linear systems.
Leveraging spatial diversity to mitigate partial band interference in undersea networks through waveform reconstruction

Many acoustic channels suffer from interference which is neither narrowband nor impulsive. This relatively long duration partial band interference can be particularly detrimental to system performance. We survey recent work in interference mitigation as background motivation to develop a spatial diversity receiver for use in underwater networks. The network consists of multiple distributed cabled hydrophones that receive data transmitted over a time-varying multipath channel in the presence of partial band interference produced by interfering active sonar signals as well as marine mammal vocalizations. In operational networks, many “dropped” messages are lost due to partial band interference which corrupts different portions of the received signal depending on the relative position of the interferers, information source and receivers due to the slow speed of propagation. Our algorithm has been tested on simulated data and is shown to work on an example from a recent undersea experiment.
Variation in modes and rates of evolution in nuclear and mitochondrial ribosomal DNA in the mushroom genus Amanita (Agaricales, Basidiomycota): phylogenetic implications.

Modes and rates of molecular evolution, and congruence and combinability for phylogenetic reconstruction, of portions of the nuclear large ribosomal subunit (nLSU-rDNA) and mitochondrial small subunit (mtSSU-rDNA) genes were investigated in the mushroom genus Amanita. The AT content was higher in the mtSSU-rDNA than in the nLSU-rDNA. A transition bias in which AT substitutions were as frequent as transitions was present in the mtSSU-rDNA but not in the nLSU-rDNA. Among-sites rate variation in nucleotide substitutions at variable sites was present in the nLSU-rDNA but not in the mtSSU-rDNA. Likelihood ratio tests indicated very different models of evolution for the two molecules. A molecular clock could be rejected for both data sets. Rates of molecular evolution in the two molecules were uncoupled: faster evolutionary rates in the mtSSU-rDNA and nLSU-rDNA were not observed for the same taxa. In separate phylogenetic analyses, the nLSU-rDNA data set had higher phylogenetic resolution. The partition homogeneity test and statistical bootstrap support for branches indicated absence of conflict in the phylogenetic signal in the two data sets; however, tree topologies produced from the separate data sets were not congruent. Heterogeneity in modes and rates of evolution in the two molecules pose difficulties for a combined analysis of the two data sets: the use of equally weighted parsimony is not fully satisfactory when rate heterogeneity is present, and it is impractical to determine a model for maximum-likelihood analysis that fits simultaneously two heterogeneous data sets. Overall topologies produced from either the separated or the combined analyses using various tree reconstruction methods were identical for nearly all statistically significant branches.
Quark model of nucleon-nucleon spin-orbit potentials

Abstract The lowest-order spin-orbit potentials between two nucleons are calculated by using nonrelativistic two-quark spin-orbit interactions obtained from meson masses. The resulting scattering matrices (calculated in the Born approximation) are compared with those from phenomenological nuclear forces. They are found to have the correct signs and roughly the correct strengths in both the T = 1 and T = 0 channels. The many uncertainties and difficulties inherent in the quark picture of nucleon-nucleon spin-orbit forces are briefly discussed.
Modulation of radical ion pair lifetimes by the presence of a third spin in rodlike donor-acceptor triads.

It is well known that the molecular structure of an electron donor−acceptor system can be changed to optimize the electronic coupling between photogenerated radical ion pairs (PRPs), resulting in favorable charge separation (CS) and charge recombination (CR) rates. It would be far more convenient to avoid extensive synthetic modifications to the structure to achieve the same ends by perturbing the electronic properties of the PRP. We present here results on PRPs within rodlike donor−acceptor molecules having a covalently attached stable 2,2,6,6-tetramethylpiperidinoxyl radical (T•). The distances and orientations between all three radicals are highly restricted by the intervening molecular structure, making it possible to directly measure both the CR dynamics and the spin−spin exchange interaction, 2JPRP, between the radicals within the PRPs. The molecular triads studied are MeOAn−6ANI−PI−T• and MeOAn−6ANI−NI−T•, where MeOAn = p-methoxyaniline, 6ANI = 4-(N-piperidinyl)naphthalene-1,8-dicarboximide, NI = n...
Layout based frequency dependent inductance and resistance extraction for on-chip interconnect timing analysis

It is well understood that frequency independent lumped-element circuits can be used to accurately model proximity and skin effects in transmission lines [7]. Furthermore, it is also understood that these circuits can be synthesized knowing only the high and the low frequency resistances and inductances [4]. Existing VLSI extraction tools however, are not efficient enough to solve for the frequency dependent resistances and inductances on large VLSI layouts, nor do they synthesize circuits suitable for timing analysis. We propose a rules-based method that efficiently and accurately captures the high and low frequency characteristics directly from layout shapes, and subsequently synthesizes a simple frequency independent ladder circuit suitable for timing analysis. We compare our results to other simulation results.
The capacity of marine plankton, macrophytes and particulate matter to adsorb Cu2+ in the presence of Mg2+

Abstract A complexometric titration technique was employed to measure the total capacity of a variety of marine organisms to adsorb Cu2+. Measured adsorption capacities were 0.22 meq g−1 for phytoplankton, 0.3–1.0 meq g−1 for macrophytes, 1.0–2.5 meq g−1 for zooplankton and ∼ 0.3 meq g−1 for suspended particulate matter. The capacity of these materials to adsorb Cu2+ was reduced significantly in the presence of Mg2+ at seawater concentrations. Competition between Mgt2+ and Cu2+ for adsorption sites at pH 6 is described by an average conditional equilibrium constant of ∼ 103.7. This constant is such that very little Cu2+ may be adsorbed onto particulates and marine phytoplankton in the presence of Mg2+. Further, primary productivity data and estimates of the detrital carbon sedimentation in Long Island Sound suggest that the flux of particulate carbon is insufficient to remove significant amounts of Cu from the water column to sediments by adsorption mechanisms.
Observing succession on aspen-dominated landscapes using a remote sensing-ecosystem approach

In the North American upper Great Lakes region, forests dominated by the aspens (Populus grandidentata Michx. – bigtooth aspen, and P. tremuloides Michx. – trembling aspen), which established after late 19th and early 20th century logging, are maturing and succession will create a new forest composition at landscape to regional scales. This study analyzed the capabilities of Landsat ETM+ remote sensing data combined with existing ecological land unit classifications to discriminate and quantify patterns of succession at the landscape scale over the 4200 ha University of Michigan Biological Station (UMBS) in northern Lower Michigan. In a hierarchical approach first multi-temporal Landsat ETM+ was used with a landscape ecosystem classification to map upland forest cover types (overall accuracy 91.7%). Next the aspen cover type was subset and successional pathways were mapped within that type (overall accuracy 89.8%). Results demonstrated that Landsat ETM+ may be useful for these purposes; stratification of upland from wetland types using an ecological land unit classification eliminated confounding issues; multi-temporal methods discriminated evergreen conifer versus deciduous understories. The Landsat ETM+ classifications were then used to quantify succession and its relationship to landform-level ecological land units. Forests on moraine and ice contact landforms are succeeding distinctly to northern hardwoods (95% and 88% respectively); those on outwash and other landforms show greater diversity of successional pathways.
Enzymatic trimethylation of residue-72 lysine in cytochrome c. Effect on the total structure

Abstract A highly purified protein methylase III from Neurospora crassa or Saccharomyces cerevisiae specifically methylates a single lysine residue of position 72 of horse heart cytochrome c . The enzymatically methylated cytochrome c has been separated from the unmethylated counterpart species by isoelectric focusing. Simultaneously, the p I values of these two species were found to be 9.49 and 10.03, respectively. Since methyl substitution increases the basicity associated with the ϵ-amino group of lysine residues, the observed decrease in p I value is in opposition to the predicted increase. Space-filling models revealed the possibility of a hydrogen bond between the oxygen of amide of residue-70 asparagine and the ϵ-amino nitrogen of residue-72 lysine in unmethylated horse heart cytochrome c . The enzymatic methylation of residue-72 lysine tends to dissociate this hydrogen bond, thereby possibly inducing the shift of ‘effective charge’ of the protein molecule. This paper alsodeals with the p I values of cytochromes c from 13 different sources, determined by the isoelectric focusing technique.
The relationship of semen quality to pregnancy rate and litter size following artificial insemination in the bitch

Abstract Artificial insemination of 31 bitches with fresh, undiluted, semen resulted in 22 31 conceptions (71%) and the birth of 124 puppies. Inseminations using at least 220 × 106 spermatozoa of normal morphology resulted in a mean pregnancy rate of 81.5% ( 22 27 ). The pregnancy rates were significantly influenced by the total number of progressively motile or morphologically normal sperm cells per ejaculate (P 0.1). Litter size was not influenced by sperm motility or morphology (P > 0.1).
Segmentation-independent estimates of turbulence parameters

We present a new approach for analyzing local power law processes and apply it to temperature measurements from the upper atmosphere. We segment the data and use the wavelet scale spectrum to estimate the parameters of the power law, the scale factor and the exponent. These parameters vary from segment to segment. Part of this variation is due to the non-stationary of the data. Another part is due to estimation errors that depend on the segmentation. In this paper show how to remove effectively these segmentation dependent variations.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Joseph K. Williams, M.D., F.A.C.S., F.A.A.P.

I would like to thank Dr. Joseph Williams for serving as guest editor of this edition of Seminars in Plastic Surgery. I would also like to thank all of the authors for their contributions to this issue.
HIV life cycle and genetic approaches

HIV-1 is a retrovirus with a complex genetic structure. The virus particle is composed of the RNA genome, structural core (Gag) proteins, enzymatic core (Pol) proteins, and structural envelope (Env) proteins. Virus infection is regulated by the expression of its receptor, CD4, on lymphocytes and macrophages. This involves specific interactions between domains of the envelope protein and CD4, and perhaps additional factors. The life cycle involves reverse transcription from the viral RNA into DNA, which may be integrated into the host chromosomal DNA. Expression of the integrated viral genome leads to an array of spliced and unspliced RNA products which encodes the virion proteins, as well as viral proteins that regulate diverse aspects of the virus life cycle. Different steps in virus entry, replication and assembly are potential targets for antiviral development. Genetics approaches have been applied in many ways for development of HIV-1 therapeutics. Analysis of sequence heterogeneity has identified specific mutations associated with drug resistance. HIV-1 nucleic acids provide valuable measures for quantitation and characterization of HIV-1 infection in infected individuals. Gene therapies are also underway and directed at HIV-1 infection.
A discussion on ‘Detection of intrusions in information systems by sequential change-point methods’ by Tartakovsky, Rozovskii, Blažek, and Kim

Abstract The discussion focuses on issues arising in practical applications of the CUSUM procedures developed by Tartakovsky et al. to detect changes in multichannel sensor systems. These issues are illustrated with a data set from the MIT Lincoln Laboratory that is used to estimate the parameters of procedures for detecting denial-of-service attacks.
New Class of Purine Mutants of Chinese Hamster Ovary Cells

Mutants of Chinese hamster ovary cells (CHO/Pro-) were isolated after mutagenesis with N-methylnitrosoguanidine and selection by the bromodeoxyuridine technique. Six of these were mutants classified as purine-requiring. The metabolic block appears to be early in the purine biosynthetic pathway. The mutants do not appear to be genetically identical.
The Point of Conflict: Risking Worth Through the Multiple Potentialities of Reflected Selves

This article adopts an existentialist lens to examine the phenomenon of entering conflict with other human beings and the potential effects of such engagement on identity. In particular, it explores a teacher's active engagement (or lack thereof) in conflict as a response to the humiliation or degradation of a student. The comfort of a secure current identity and the risk that conflict poses to such an identity is posited as both the catalyst and barrier to active engagement. The point of conflict presents the teacher with a choice between self-protection and courageous sacrifice. This article attempts to expose the under-workings of such a decision through the use of narrative, depicting a situation of potential conflict between teacher and student.
Uses of Multivariate Analytical Techniques in Online and Blended Business Education: An Assessment of Current Practice and Recommendations for Future Research.

Seeking to assess the analytical rigor of empirical research in management education, this article reviews the use of multivariate statistical techniques in 85 studies of online and blended managem...