cssi/SciSciGPT-SciSciNet huggingface dataset:
Structural transitions of deoxyribonucleic acid in aqueous electrolyte solutions. II. The role of hydration.

The data and approach reported in paper I (Hanlon et al., 1975, preceding paper) have been used to calculate the fractional changes in secondary structure of calf thymus deoxyribonucleic acid which occur in aqueous solutions as a function of the concentration of NaCl, KCl, LiCl, CsCl, and NH4Cl. There is a continuous loss in the "B" character of the nucleic acid with concomitant production of the C and, in some instances, an A form, as well, as the salt concentration increases. Sedimentation velocity studies suggest that there is an accompanying change in the hydrodynamic characteristics of the DNA molecules, as well. Utilizing the existing hydration data in the literature (Hearst and Vinograd, 1961a,b; Hearst, 1965; Tunis and Hearst, 1968a; Cohen and Eisenberg, 1968; Falk et al., 1962, 1963a,b), we have found that a gradual loss of "B" character and a decrease in the frictional coefficient of DNA occur as the net hydration of DNA is reduced from the fully hydrated from (60-80 mol of H2O/mol of nucleotide) to values of ca. 12-14 mol of H2O/mol of nucleotide. Below that value, a more precipitous decrease in these properties occurs. Extrapolation of the linear relationship observed between the fractional B content and the net hydration in the latter regions yield values of ca. 18 mol of H2O/mol of nucleotide at 100% B and ca. 4 mol of H2O/mol of nucleotide at 0% B (i.e., 100% C or C + A) for the alkali metal salts of DNA. The ammonium salt retains somewhat more H2O in the C and A forms (ca. 7). These results together with the hydration site assignments of Falk et al. (1962, 1963a,b) are interpreted in terms of a hydration model for DNA in aqueous solution in which an intact primary hydration shell of ca. 18 mol of H2O/mol of nucleotide is required for the maintenance of the "B" conformation. Removal of all but those water molecules solvating the phosphate groups results in the conversion to the C forms, predominantly, with a small amount of A structure formed as well in some salts. The accompanying changes in the sedimentation coefficients suggest that the DNA molecule assumes a more compact and/or flexible form under these conditions in which it is mainly in the C and A structures. The combination of these two events which ensue upon dehydration create a polymeric structure which can be more easily packaged in biological systems.
Frequency Response of Piezoelectric and Magnetostrictive Hysteretic Nonlinear Systems

Piezoelectric and magnetostrictive materials exhibit high energy densities and broadband drive capabilities enabling compact actuator designs. These applications include acoustic transducers, nano-positioning systems such as Atomic Force Microscopes (AFM) and other smart actuators for precise control of displacement. However, these materials exhibit hysteresis and constitutive nonlinearities at all drive levels. Quantification and understanding these effects on the frequency domain behavior of the materials is necessary for precise control of displacement as well as developing control strategies to alleviate the higher harmonics produced during operation. Whereas considerable effort has been made on model development and understanding these materials in parameter space and time domain, a comprehensive understanding in frequency domain is lacking. Here we quantify the effect of hysteresis, nonlinearities, bias fields and AC drive levels on the frequency domain behavior.Copyright © 2008 by ASME
The effect of fructose derived carbon shells on the plasmon resonance and stability of silver nanoparticles

Carbon nanoparticles between 10 and 50 nm in diameter and carbon shells of various thickness around silver nanoparticles were synthesized by the hydrothermal reaction of fructose. The effect of the carbon shells on the plasmon resonance of the silver nanoparticles and their stability in sodium chloride solutions was investigated. The shell thickness can be adjusted to have insignificant damping of the plasmon resonance and provide stabilization of the particles in solutions with high ionic strength. Hydrazine–carbonyl cross-linking reactions were performed to link fluorescent dye molecules to carbonyl groups on the carbon shell surface.
Production of Sunfish Lepomis spp. in Ponds Treated with Controlled‐Release Fertilizers

.– Controlled-release fertilizer in pond water released nutrients according to the pattern reported for exposure in soil. A single application of controlled-release fertilizer (13% N, 13% P2O5, 13% K2O) was compared with multiple applications of conventional, liquid fertilizer (10% N, 34% P2O5, 0% K2O) for augmenting sunfish production in ponds. Liquid fertilizer was used at an annual phosphorus input rate of 39.3 kg/ha; controlled-release fertilizer was applied at 19.7, 9.8, and 4.9 kg phosphorus/ha per yr. Phytoplankton abundance inferred from chlorophyll u and Secchi disk visibility estimates and phytoplankton photosynthesis measured by the oxygen, light-dark bottle method were similar in ponds treated with liquid fertilizer and in ponds that received controlled-release fertilizers at the two highest rates. Net sunfish production did not differ among ponds treated with 39.3 kg phosphorus/ha in liquid fertilizer or 19.7 and 9.8 kg phosphorus/ha applied in controlled-release fertilizer. Controlled-release fertilizer used in this study contained more nitrogen and potassium than needed, but a custom, controlled-release fertilizer with the proper ratio of nutrients can be made. This fertilizer would have the advantage of requiring only a single application at the beginning of the growing season, and amounts of soluble reactive phosphorus in outflow from ponds could be reduced by using controlled-release fertilizers.
Preliminary bioequivalence testing of two nicardipine HCl sustained-release formulations with in vitro/in vivo correlations.

A new nicardipine HCl oral sustained-release dosage form was evaluated for bioequivalence in comparison with a reference product, Cardene® SR. Six healthy subjects, fasted overnight, were enrolled in a single-dose, open-label, randomized, and two-way crossover study. Blood samples were collected over a 12 hour period, and nicardipine plasma concentrations analyzed from plasma. Pharmacokinetic parameters, including Cmax, tmax, and AUC, were obtained from drug plasma concentration-time curves and pharmacokinetic, analysis conducted using WinNonlin®. The two one-sided t-test was applied in statistical analysis for comparison of the pharmacokinetic parameters between the two products. There was no convincing evidence that nicardipine HCl test product and Cardene® SR were bioequivalent. Amounts of nicardipine HCl release in vivo was mathematically obtained by deconvoluting plasma concentration-time data after oral administration using IV bolus injection data as a reference. Plots of percentages of drug release in vitro against those in vivo illustrated triphasic curves. After the in vitro time scale was corrected and then plotted against in vivo data, plots provided a polynomial relationship (R2 of 0.9920 and 0.9954). The in vitro/in vivo correlation may be useful in reformulating this particular test formulation to obtain a product with an in vivo release rate identical to Cardene® SR.
The determination of arginine released in human blood plasma after plasminogen activation. Use of a cation-exchange resin.

Abstract A method is outlined for the determination of the arginine released after activation of the plasminogen in human blood plasma based on the separation of this amino acid directly from plasma on sodium-cycled cation-exchange resin, elution of the adsorbed amino acid, and determination with the modified Sakaguchi reagent.
Performance Measurement of 802.11a Wireless Links from UAV to Ground Nodes with Various Antenna Orientations

We report measured performance of 802.11a wireless links from an unmanned aerial vehicle (UAV) to ground stations. In a set of field experiments, we record the received signal strength indicator (RSSI) and measure the raw link-layer throughput for various antenna orientations, communication distances and ground-station elevations. By comparing the performance of 32 simultaneous pairs of UAV and ground station configurations, we are able to conclude that, in order to achieve the highest throughput under a typical flyover UAV flight path, both the UAV and the ground station should use omni-directional dipole (as opposed to high-gain, narrow- beam) antennas positioned horizontally, with their respective antenna null pointing to a direction perpendicular to the UAV's flight path. In addition, a moderate amount of elevation of the ground stations can also improve performance significantly.
Using an Event History Analysis to Evaluate Social Welfare Programs

This article presents an overview of how an event history analysis can be used to evaluate social welfare programs' impacts on events and the timing of events. An overview of event history analysis is presented, including a discussion of events and spells, hazards, censoring, duration intervals, longitudinal databases, design issues, and life table and multivariate analysis techniques. The article concludes with an example of how an event history analysis was used to evaluate the Aid to Families with Dependent Children (AFDC) program.
Rapid prototyping 3D objects from scanned measurement data

It has become increasingly important to be able to generate free-form 3D shapes in commercial applications using rapid prototyping technologies. In many cases, the shapes of interest are taken from real-world objects that do not have pre-existing computer models. Constructing an accurate model for these objects by hand is extremely time consuming and difficult with even the latest 3D software packages. To aid in the modeling process, 3D scanners are used to capture the object shape and generate a high resolution model of the object. However, these models built from scans often have irregularities that prevent the construction of a useful prototype. This paper proposes a method for generating 3D models suitable for rapid prototyping from measurements of real-world objects taken by a 3D scanner. This is accomplished by taking a cloud of 3D point data as input and fitting a closed 3D surface to the data in such a way as to ensure accuracy in the representation of the object surface and compatibility with a rapid prototyping machine. We treat surface modeling and adaptation to the data in a new framework as 3D stochastic surface estimation.
Traumatic brain injury-induced axonal phenotypes react differently to treatment

Injured axons with distinct morphologies have been found following mild traumatic brain injury (mTBI), although it is currently unclear whether they reflect varied responses to the injury or represent different stages of progressing pathology. This complicates evaluation of therapeutic interventions targeting axonal injury. To address this issue, we assessed axonal injury over time within a well-defined axonal population, while also evaluating mitochondrial permeability transition as a therapeutic target. We utilized mice expressing yellow fluorescent protein (YFP) in cortical neurons which were crossed with mice which lacked Cyclophilin D (CypD), a positive regulator of mitochondrial permeability transition pore opening. Their offspring were subjected to mTBI and the ensuing axonal injury was assessed using YFP expression and amyloid precursor protein (APP) immunohistochemistry, visualized by confocal and electron microscopy. YFP(+) axons initially developed a single, APP(+), focal swelling (proximal bulb) which progressed to axotomy. Disconnected axonal segments developed either a single bulb (distal bulb) or multiple bulbs (varicosities), which were APP(-) and whose ultrastructure was consistent with ongoing Wallerian degeneration. CypD knock-out failed to reduce proximal bulb formation but decreased the number of distal bulbs and varicosities, as well as a population of small, APP(+), callosal bulbs not associated with YFP(+) axons. The observation that YFP(+) axons contain several pathological morphologies points to the complexity of traumatic axonal injury. The fact that CypD knock-out reduced some, but not all, subtypes highlights the need to appropriately characterize injured axons when evaluating potential neuroprotective strategies.
Nutritional Value of Blighted Corn as Silage or as Grain

Abstract Digestibility trials with 300 to 350kg steers indicated no significant difference between blighted and normal corn silage or grain as a feedstuff for growing beef steers. Extra care in harvesting and processing is recommended to prevent secondary problems with blighted feedstuffs.
Endoscopic Therapy for Barrett's Esophagus

Recent retrospective cohort data and a prospective randomized sham controlled trial have clearly documented the impact of endoscopic ablation therapy on dysplasia and Barrett's esophagus (BE). The clinical indications for ablation of BE includes high-grade dysplasia and intramucosal adenocarcinoma. The techniques of resection of mucosal irregularities and of ablation are reviewed, primarily thermal and photodynamic ablation. Ablation of BE with neoplasia has appropriately entered the clinical arena.
Real-world calibration of GOES-8 and -9 sensors

The calibration processing algorithms currently in effect for the GOES-8 and -9 imagers and sounders are described. The algorithms have been changed since the launch of GOES-8. Smoothing of the calibration slopes has been instituted to suppress the effects of noise in the blackbody sequences. In the visible channel, the signal, originally transmitted to users in absolution counts, is now provided relative to the signal from space. The operational calibration equations were generalized to eliminate errors caused by the variation of the reflectances of the instruments' scan mirrors with east-west scan position, which was discovered after the launch of GOES-8. We are in the process of developing processing changes to mitigate the effects of two other anomalies--the appearance of east-west stripes in the infrared images from the imagers; and erroneous calibrations around midnight during six months of the year, caused by the presence of unwanted radiation from hot components of the imagers' and sounders' telescopes during the calibration sequences. Instructions are given on how to convert the counts in the GVAR data stream to radiances, temperatures, and mode-A counts.
A review of possible health concerns associated with zero net energy homes

The purpose of this paper is to identify potential human health concerns that may arise from the increasing popularity of zero net energy homes (ZNEH) a form of high-performance green building in the US. Since high levels of energy consumption are not sustainable, ZNEH has the potential to reduce the environmental impact without penalty to occupants by providing a healthy home environment at low energy inputs. The premise of this article is that ZNEHs can indeed maintain high levels of health while reducing energy consumption. However, the potential for health impacts must be investigated. In this brief essay, main health questions that might arise in relationship to ZNEHs are reviewed. In addition, potential areas for additional research on zero net energy homes and their effects on human health are identified. This topic remains in its infancy and is a viable area of research that will benefit greatly from additional research.
Error sum of squares and power comparisons for model search, identification and discrimination

Abstract The model search, identification, and discrimination between models within a specified class of models are considered for finding the best model in describing the data. Two criterion functions, error sum of squares and power for testing the uncommon parameter in the models, are used for this purpose. Some general results with special reference to 2 m fractional factorial plans are presented.
Sampling Broiler Litter: How Many Samples Are Needed?

SUMMARY Poultry litter can be sampled from chicken house floors, storage piles, or at cleanout. Existing guidelines typically advise to obtain a composite sample from an arbitrary number of subsamples that can be taken randomly or systematically. If nutrients in poultry litter differ in the variability of their concentrations, the number of subsamples needed to obtain reliable analytical results should be a direct function of their variabilities. Our work documented the variability in the concentrations of nutrients in broiler litter, when samples were taken from different parts of a commercial chicken house and from the trucks at cleanout. Additionally, using conventional statistical and computer-intensive random resampling methods, we calculated the number of subsamples needed for the mean concentrations of components to be within specified ranges from the experimental mean 95% of the time. The results showed wide differences in the variability of nutrient concentrations and the advantage of sampling after the broiler litter has undergone some degree of mixing, as may take place during cleanout.
The adverse effects of diabetes on osteoarthritis: update on clinical evidence and molecular mechanisms

Projected increases in the prevalence of both diabetes mellitus (DM) and osteoarthritis (OA) ensure their common co-existence. In an era of increasing attention to personalized medicine, understanding the influence of common comorbidities such as DM should result in improved care of patients with OA. In this narrative review, we summarize the literature addressing the interactions between DM and OA spanning the years from 1962 to 2014. We separated studies depending on whether they investigated clinical populations, animal models, or cells and tissues. The clinical literature addressing the influence of DM on OA and its therapeutic outcomes suggests that DM may augment the development and severity of OA and that DM increases risks associated with joint replacement surgery. The few high quality studies using animal models also support an adverse effect of DM on OA. We review strengths and weaknesses of the common rodent models of DM. The heterogeneous literature derived from studies of articular cells and tissues also supports the existence of biochemical and biomechanical changes in articular tissues in DM, and begins to characterize molecular mechanisms activated in diabetic-like environs which may contribute to OA. Increasing evidence from the clinic and the laboratory supports an adverse effect of DM on the development, severity, and therapeutic outcomes for OA. To understand the mechanisms through which DM contributes to OA, further studies are clearly necessary. Future studies of DM-influenced mechanisms may shed light on general mechanisms of OA pathogenesis and result in more specific and effective therapies for all OA patients.
Theoretical analysis of the role of the infernal mode in the stability of peaked pressure profiles in pellet fuelled JET discharges

The very peaked pressure profiles in some pellet fuelled discharges with ion cyclotron resonance heating in the Joint European Torus (JET) are terminated by an abrupt flattening of the temperature profile. This appears to be the result of an instability with a very fast time-scale that is triggered when the safety factor q drops below 1.5. The ideal m/n = 3/2 infernal mode, which is excited only when q is very close to 1.5, may well be the responsible instability. Linear magnetohydrodynamic stability calculations, based on equilibria that model the relevant JET discharges as closely as possible, yield growth rates consistent with the rise time of the instability. Non-linear calculations initialized with the same equilibria exhibit plasma behaviour very similar to that seen experimentally: (1) a flattening of the pressure profile occurs, (2) a residual m = 3 structure is present after the flattening, and (3) the time-scale for the flattening is in reasonable agreement with experimental observations. It is thus concluded that the ideal infernal mode is a viable candidate for the instability.
Wolf scent marking with raised-leg urination

Raised-leg urinations were performed almost exclusively by dominant male and female wolves (Canis lupus). The alpha male and female in two captive groups showed full raised-leg urinations (RLUs) throughout the year. Each alpha male and female sniffed and marked on one another's marks frequently; however, the pair that bred did more marking and more double marking. They increased their marking frequency prior to and during the breeding season, decreased it at the time of parturition, while the female was in the den, and then increased to a moderate level when the female took part in pack activities again. Because the alpha pair was the principal sender and receiver of the message within the group, it is likely that double marks function to maintain and advertise the pair bond. Because the group that did not breed also did not double mark frequently, the presence of double marking in a captive group may be diagnostic of the viability of the group as a pack.
Excitatory Neuromuscular transmission in crayfish: calcium dependence is unaffected by picrotoxin.

Picrotoxin, 1 × 10−5M to 1.6 × 10−3M, had little or no effect on the amplitude of intracellularly recorded excitatory junctional potentials (EJPs) at extracellular calcium concentrations [Ca2+]0 ranging from 0.5 to 15 mM. The slope of the log EJP vs. log[Ca2+]0 relationship was approximately 1 with or without picrotoxin. The reduction of EJP amplitude resulting from the addition of 5 × 10−5M GABA was largely reversed by 10−5M picrotoxin.
Cocaine effects are modulated by central CB2 receptors in mice: new hope in a cannabinoid target for addiction and other CNS disorders

Evaluation of: Xi ZX, Peng XQ, Li X et al. Brain cannabinoid CB2 receptors modulate cocaine’s actions in mice. Nat. Neurosci. 14(9), 1160–1166 (2011). This study aimed to investigate the possible involvement of brain CB2 receptors in cocaine’s behavioral and neurochemical effects by using highly selective CB2 receptor agonists and antagonists, combined with CB1 and CB2 receptor knockout mice. They found that systemic or intracerebral administration of the CB2 selective agonist, JWH133, dose-dependently inhibited intravenous cocaine self-administration, cocaine-induced locomotion and cocaine-induced nucleus accumbens extracellular dopamine in wild-type and CB1 receptor knockout mice, but not in CB2 receptor knockout mice. These findings indicate that brain CB2 receptors modulate cocaine’s reinforcing and locomotor-stimulating effects, likely through a dopamine-dependent mechanism, and further suggest that selective ligands targeting brain CB2 receptors may represent a novel target for cocaine and other dru...
Center of inertia for the post-Newtonian n-body problem in gravitation with PPN parameters γ and β

Abstract We find the center of inertia for the case of the post-Newtonian n -body lagrangian (in standard coordinates) with PPN parameters γ and β, and find that the potential energy term - Gm i m j / r ij splits equally between the particles i and j .
Synthesis and analytical characterization of the sodium salt of heptakis(2-O-methyl-3,6-di-O-sulfo)cyclomaltoheptaose, a chiral resolving agent candidate for capillary electrophoresis.

Abstract A pure, single isomer, strong electrolyte chiral resolving agent candidate for capillary electrophoresis, the sodium salt of heptakis(2-O-methyl-3,6-di-O-sulfo)cyclomaltoheptaose has been synthesized on the 100-g scale, in greater than 97% purity, through heptakis(2,6-di-O-tert-butyldimethylsilyl)cyclomaltoheptaose, heptakis(2-O-methyl-3,6-di-O-tert-butyldimethylsilyl)cyclomaltoheptaose and heptakis(2-O-methyl)cyclomaltoheptaose intermediates. The structural identity of each intermediate and the final product was conclusively established by high-resolution MALDI-TOF mass spectrometry, variable-temperature 1H and 13C NMR spectroscopy and X-ray crystallography. The purity of each intermediate and the final product was determined by gradient high-performance liquid chromatography (HPLC) and indirect UV detection capillary electrophoresis.
Heat transfer and pressure drop in narrow rectangular channels

Abstract Recently, with the advent of more powerful electronic chips and the miniaturization of electronic circuits and other compact systems, a great demand exists for developing efficient heat removal techniques to accommodate these high heat fluxes. With this objective in mind, both single-phase forced convection and subcooled and saturated nucleate boiling experiments have been performed in small rectangular channels using FC-84 as test fluid. The test section used in these experiments consisted of five parallel channels with each channel having the following dimensions: hydraulic diameter (Dh)=0.75 mm and length to diameter ratio (L/Dh)=409.8. The experiments were performed with the channels oriented horizontally and uniform heat fluxes applied at the top and bottom surfaces. The parameters that were varied during the experiments included the mass flow rate, inlet liquid subcooling, and heat flux. In each of the experiments conducted, the temperature of both the liquid and the wall were measured at various locations along the flow direction. Based on the measured temperatures, pressure drops, and the overall energy balance across the test section, the heat transfer coefficients for both single-phase forced convection and flow boiling has been calculated. Additionally, in these experiments, the single- and two-phase pressure drop across the channels was also measured. A correlation has been developed for two-phase flow pressure drop under subcooled and saturated nucleate boiling conditions. Furthermore, two new correlations are proposed – one for subcooled flow boiling heat transfer and the other for saturated flow boiling heat transfer.
Thought on the Convergence of Digital Media, Memory, and Social and Urban Spaces

In this article, the relationship between the development of digital media and memory,community, and urban spaces is discussed. It is based on a project sponsored by the European Commissioni3 and was developed by a consortium of five partners between 1997 and 2000. The project’s name is Living Memory (LiMe), which is a communication system prototype. LiMe aims to provide members of a locality with means to capture, share, and explore their collective memory and experiences and is an intelligent network of interfaces embedded within the physical fabric of the local community, supporting the creation and distribution of informal content within that community. LiMe interfaces are in natural meeting and crossing points, such as cafes and bus stops. People do not have to sit behind computers to create and find information but come across local knowledge incidentally and peripherally in everyday locations. LiMe is about discovering, expressing, and getting out in the local physical neighborhood.
What's a working set?

I am writing about the paper by A. Petrella and H. Farrey, of IBM, SIMULATING WORKING SETS UNDER MVS, reprinted in the SIGMETRICS Newsletter, Issue (8, 4), winter 1979-80. The paper is an amalgam of very good modeling work and misinformation about the working set concept. I will summarize the important contributions and give a short essay about working sets.
Nanofabrication of III?V semiconductors employing diblock copolymer lithography

To fully exploit the potential advantages of ideal quantum dots (QDs) (i.e. full 3D carrier confinement), elimination of the wetting layer and a uniform monomodal QD size distribution is needed. Nanopatterning with selective metalorganic chemical vapour deposition (MOCVD) QD growth has potential for achieving a higher degree of control over the QD formation, compared with the conventional Stranski–Krastanov (SK) self-assembly growth process. QD formation employing large surface area patterning prepared by dense nano-scale (20–30 nm diameter) diblock copolymer lithography is described. The resulting pattern consists of perpendicularly ordered cylindrical domain formed as part of a self-organizing diblock copolymer, such as polystyrene-block-poly(methylmethacrylate) (PS-b-PMMA). This pattern can be transferred to an underlying substrate or dielectric layer. Selective MOCVD growth of the QDs is achieved by employing the nanopatterned template mask. The resulting QD densities of 5 × 1010 cm−2 are comparable to densities achieved using the SK self-assembly growth mode. Nanopatterned growth yields a nearly monomodal QD size distribution. Variable temperature photoluminescence has been used to characterize the optical properties of capped InGaAs QDs on GaAs (λ ~ 1.1 µm) and InP (λ ~ 1.5 µm) substrates and preliminary results on the incorporation of such materials into diode laser structures are discussed. The extension of nanopatterned growth, beyond the pseudomorphic limit in the case of growth of strained-layer epitaxy, can lead to defect reduction and an improved morphology when compared with non-patterned growth.
Finite element method for hydrodynamic mass with nonstationary fluid

Abstract In this investigation, a method has been developed for determining the hydrodynamic mass of a body in fluid. It is applied to the impeller stage of a centrifugal pump. In comparison with other added mass approaches, two main features have been included: (1) an accurate representation of the three-dimensional geometry of the pump; (2) the effects of the velocity of the fluid. The method is based on a linear perturbation technique which assumes that the disturbance in the pump's flow boundaries and velocities caused by motion of the rotor are small. A potential method is used to estimate the velocity flow fields. The hydrodynamic mass is then obtained by calculating the total force which results from the pressures induced by perturbation of the rotor.
Regulation of spermatogenesis by small non-coding RNAs: Role of the germ granule

The spermatogenic process relays in highly regulated gene expression mechanisms at the transcriptional and post-transcriptional levels to generate the male gamete that is needed for the perpetuation of the species. Small non-coding RNA pathways have been determined to participate in the post-transcriptional regulatory processes of germ cells. The most important sncRNA molecules that are critically involved in spermatogenesis belong to the miRNA and piRNAs pathways as illustrated by animal models where ablation of specific protein components displays male infertility. Several elements of these regulatory pathways have been found in the nuage or germ granule, a non-membranous cytoplasmatic structure that can be seen in spermatocytes and spermatids. This notion suggests that germ granules may act as organizer centers for silencing pathways in the germline. In general, miRNAs regulate spermatogenesis through targeting and down-regulation of specific transcripts to eventually promote sperm development. However, piRNAs are powerful repressors of transposon elements expression in the spermatogenic process. Here we describe the suggested functions that miRNA and piRNAs pathways execute in the regulation of spermatogenesis and include some recent studies in the field. Despite major strides on the detailed molecular mechanisms of sncRNAs in relation to spermatogenesis, there is plenty to discover on this fascinating regulatory program.
Assessing the generalizability of smoking studies

We used data from the 1986 Adult Use of Tobacco Survey, 10 studies of self-quitters and seven studies of treatment seekers, to illustrate how subpopulations of smokers might differ; e.g. treatment seekers vs. self-quitters and research volunteers vs. smokers in the general population. Smoking researchers may wish to use our results to determine whether their sample is similar to the population of interest.
Computers and instruction: Implications of the rising tide of criticism for reading education

Abstract As the implications of computer applications in reading education have become clear, an increasing variety of objections have been raised. Computers were initially uncritically accepted in classrooms due to a popular misunderstanding of their potential. Lack of theoretical and research knowledge about the reading process on the part of school administrators contributed to the confusion in initial introduction of computers into reading instruction. In fact, many of the reasons used to support computer‐based education have no basis in fact. This article surveys a variety of criticisms targeted toward some aspects of computer‐based instruction in reading in an effort to direct attention to the beneficial implications of computers in the classroom.
Congeneric and (Essentially) Tau-Equivalent Estimates of Score Reliability What They Are and How to Use Them

Coefficient alpha, the most commonly used estimate of internal consistency, is often considered a lower bound estimate of reliability, though the extent of its underestimation is not typically known. Many researchers are unaware that coefficient alpha is based on the essentially tau-equivalent measurement model. It is the violation of the assumptions required by this measurement model that are often responsible for coefficient alpha's underestimation of reliability. This article presents a hierarchy of measurement models that can be used to estimate reliability and illustrates a procedure by which structural equation modeling can be used to test the fit of these models to a set of data. Test and data characteristics that can influence the extent to which the assumption of tau-equivalence is violated are discussed. Both heuristic and applied examples are used to augment the discussion.
Enhanced learning following a single, acute dose of MDA.

Abstract The behavioral effects of a single, acute dose of methylenedioxyamphetamine (MDA) were assessed using the rabbit nictitating membrane (NM) preparation. Acquisition of the classically conditioned NM response was carried out in a single session under MDA at doses of 10 and 20 μmol/kg (1.79 and 3.58 mg/kg, respectively) and retention was assessed during a drug-free state 48 h later. In agreement with previous reports, MDA at a dose of 10 μmol/kg enhanced acquisition of the conditioned NM response and learning was retained in the nondrug state. However, MDA at a dose of 20 μmol/kg failed to affect either acquistion or retention. In further agreement with previous reports, MDA at 10 μmol/kg facilitated the amplitude of the unconditioned response during unpaired stimulus presentations. It is suggested that this enhanced motor response may be due to enhanced neural transmission in the afferent limb of the unconditioned reflex arc.
Application of Multivariate Statistical Methodology to Model Factors Influencing Fate and Transport of Fecal Pollution in Surface Waters

The increasing number of polluted watersheds and water bodies with total maximum daily loads (TMDLs) has resulted in increased research to find methods that effectively and universally identify fecal pollution sources. A fundamental requirement to identify such methods is understanding the microbial and chemical processes that influence fate and transport of fecal indicators from various sources to receiving streams. Using the Watauga River watershed in northeast Tennessee as a model to better understand these processes, multivariate statistical analyses were conducted on data collected from four creeks that have or are expected to have pathogen TMDLs. The application of canonical correlation and discriminant analyses revealed spatial and temporal variability in the microbial and chemical parameters influencing water quality, suggesting that these creeks differ in terms of the nature and extent of fecal pollution. The identification of creeks within a watershed that have similar sources of fecal pollution using this data analysis approach could change prioritization of best management practices selection and placement. Furthermore, this suggests that TMDL development may require multiyear and multisite data using a targeted sampling approach instead of a 30-d geometric mean in large, complex watersheds. This technique may facilitate the choice between watershed TMDLs and single segment or stream TMDLs.
Electrochemistry of Cu(I) bipyridyl complexes with alkene, alkyne, and nitrile ligands. Implications for plant hormone action of ethylene.

The redox behavior was evaluated for several (BIPY)Cu(I) complexes (BIPY = 2,2′-bipyridyl) with unsatur ated ligands by means of cyclic voltammetry in CH2Cl2 at reduced temperatures (— 78°,—23°, 0°C). The complexes studied are [Cu(I)(BIPY)(C2H2)]PF6, [Cu(I)(BIPY)(3-hexyne)]PF6, [Cu(I)(BIPY)(DEAD)]PF6, {[CU(I)(BIPY)]2DEAD}[PF6]2 (DEAD = diethyl acetylene dicarboxylate) and [Cu(I)(BIPY)(CH3CN)]PF6. The oxidations are quasi-reversible at — 78°C for scan rates of 20 to 200mV/sec. The reductions were irreversible on the CV time scale. Evidence is presented in support of a role for an electron transfer mechanism in the case of the plant hormone ethylene. Related literature data are also discussed.
An intergenerational approach to understanding Taiwanese American adolescent girls' and their mothers' perceptions about sexual health.

Taiwan-born mothers' perceptions of sexual health affect their Taiwanese American girls' sexual perceptions. Taiwanese American girls grow up balancing two different cultural influences (Taiwanese and American) while living in the majority society. The process of balancing two different cultures is called bicultural straddling. Four separate focus group interviews with two sets of mothers and daughters ( N = 20) were conducted to understand intergenerational transmission of thoughts, perceptions, values, and attitudes associated with sex-related taboos and their impact on sexual communication, safety, and sexual health of second-generation Taiwanese American girls. The findings suggest that mother—daughter relationships, particularly mothers' traditional cultural values, influence their daughters' decision-making process. A secondary finding suggests that these girls tend to experience mental strain if they decide to go against their mothers' advice. Implications are that maternal involvement should be in...
Minimum Differentiation in Commercial Media Markets

We examine a model of locational choice in commercial media markets. Commercial media (stations) compete for audiences with their choice of programming variety in order to attract advertising revenues from advertisers. These advertisers (producers) compete in a differentiated product market and rely on advertising to inform consumers about their product. We use the model to show that media have incentives to minimize the extent of differentiation between them. This incentive is an implication of the assumed role of advertising as information and as an ultimate nuisance to the audience. When stations minimally differentiate their programming offerings, producers choose lower levels of advertising. Consequently, lower levels of product information are available to consumers, permitting producers to gain higher margins on product sales. As a result, stations can negotiate higher payments for advertising space.
Intravaginal ring delivery of tenofovir disoproxil fumarate for prevention of HIV and herpes simplex virus infection

OBJECTIVES: A safe and effective topical prevention strategy will likely require sustained delivery of potent antiviral drugs and a delivery system that simultaneously maximizes drug distribution and overcomes the behavioural challenges related to adherence. Activity against HIV and herpes simplex virus (HSV) would be advantageous given the epidemiological link between the two pathogens. We hypothesize that tenofovir disoproxil fumarate (tenofovir DF) a prodrug of tenofovir may be more potent than tenofovir and ideal for sustained intravaginal ring (IVR) delivery. METHODS: The anti-HIV and anti-HSV activity of tenofovir and tenofovir DF were assessed in cell and explant models. Cumulative tenofovir DF release and stability from polyether urethane (PEU) ethylene-co-vinyl acetate (EVA) and silicone IVRs were compared and the activity and safety of drug released were evaluated in cervical explants and in a polarized dual-chamber model. RESULTS: Tenofovir DF inhibited HIV and HSV at approximately 100-fold lower concentrations than tenofovir and retained activity in the presence of semen. PEU rings delivered >1 mg/day of tenofovir DF for 30 days. Pre-treatment of cervical explants with 10 mug/mL tenofovir DF or eluants from PEU minirings resulted in >90% inhibition of HIV and reduced HSV-2 yields by 2.5 log. Tenofovir DF and eluants did not prevent cell growth or polarization or have any deleterious effects on an epithelial barrier. CONCLUSIONS: The findings support the development of a PEU tenofovir DF ring which may provide potent and sustained protection against HIV and HSV.
Effects of Herbicides on Root Rot and Damping-off Caused by Rhizoctonia solani in Glyphosate-Tolerant Soybean

Diseases caused by Rhizoctonia solani are one of many production constraints in soybean-growing regions. Little information is available about the diseases in soybeans tolerant to different herbicides. In 1998 and 1999, studies were conducted to evaluate the plausible interaction between glyphosate-tolerant soybean and herbicides (glyphosate, imazethapyr, lactofen, and pendimethalin) on damping-off and root rot caused by R. solani under greenhouse and field conditions. The herbicides were applied at the product recommended field rate on glyphosate-tolerant (Pioneer 93B01 and Pioneer 9344) and glyphosate-sensitive (BSR 101) soybean grown in soils infested with R. solani (isolate AG-4). Root rot and plant stand was significantly affected by soybean cultivars and herbicide treatments in the greenhouse study. A significant cultivar-treatment interaction was detected in the greenhouse study. The interaction implies that the cultivars responded differently to the various herbicides and especially to the herbicide pendimethalin. Plant stands of both cultivars were reduced by R. solani alone or in combination with different herbicides compared with the noninoculated control, and this was presumed to be due to damping-off. In a 2-year field study, cultivar and treatment main effects differed with respect to plant stand between years. In 1998, analysis of variance revealed a significant treatment effect on root rot severity but not plant stand. In 1999, analysis of variance revealed a significant effect of treatment on root rot severity and plant stand whereas cultivar showed a significant effect on plant stand only. In 1999, plant stands of both cultivars were similarly affected by most treatments. However, in BSR 101, the R. solani + pendimethalin + imazethapyr treatment significantly reduced plant stand compared with the R. solani + pendimethalin treatment. Root rot severity was generally low in both years of the field study. Some differential disease responses were detected between glyphosate-tolerant and glyphosate-sensitive cultivars following the application of certain herbicides in greenhouse and field studies. However, glyphosate-tolerant and glyphosate-sensitive cultivars reacted similarly to most herbicide treatments with respect to root rot and damping off.
The HCMV membrane glycoprotein US10 selectively targets HLA-G for degradation

Human cytomegalovirus (HCMV) encodes an endoplasmic reticulum (ER)-resident transmembrane glycoprotein, US10, expressed early in the replicative cycle of HCMV as part of the same cluster that encodes the known immunoevasins US2, US3, US6, and US11. We show that US10 down-regulates cell surface expression of HLA-G, but not that of classical class I MHC molecules. The unique and short cytoplasmic tail of HLA-G (RKKSSD) is essential in its role as a US10 substrate, and a tri-leucine motif in the cytoplasmic tail of US10 is responsible for down-regulation of HLA-G. Both the kinetics of HLA-G degradation and the mechanisms responsible appear to be distinct from those used by the US2 and US11 pathways, suggesting the existence of a third route of protein dislocation from the ER. We show that US10-mediated degradation of HLA-G interferes with HLA-G–mediated NK cell inhibition. Given the role of HLA-G in protecting the fetus from attack by the maternal immune system and in directing the differentiation of human dendritic cells to promote the evolution of regulatory T cells, HCMV likely targets the HLA-G–dependent axis of immune recognition no less efficiently than it interferes with classical class I MHC–restricted antigen presentation.
The Relative Merits of Two Statistics for Testing a Hypothesis about the Equality of Three Correlated Proportions

Abstract The small-sample properties of the Cochran Q and the Neyman minimum x 2 statistic (N M) were investigated. Both statistics provide tests of a hypothesis about the equality of correlated proportions. In the cases considered, N M always rejects the null hypothesis at a rate greater than the expected nominal α level, whereas Cochran's Q usually rejects this hypothesis at a rate less than the expected level. In most of the comparisons made, the observed versus expected deviation is smaller for Q than for N M; the exceptions involve those cases where the symmetric covariance condition is severely violated. Of ancillary interest is a comparison of two procedures for calculating N M when a singular covariance matrix is encountered.
Studies in Script Theory: II. Altruistic Nuclear Scripts:

A serious lack in the extensive research literature on altruism, helping, and prosocial behavior is a personological perspective: a coherent theory of personality, coupled with case studies of comm...
Spherical Collapse and the Halo Model in Braneworld Gravity

We present a detailed study of the collapse of a spherical perturbation in Dvali-Gabadadze-Porrati (DGP) braneworld gravity for the purpose of modeling simulation results for the halo mass function, bias, and matter power spectrum. The presence of evolving modifications to the gravitational force in the form of the scalar brane-bending mode leads to qualitative differences to the collapse in ordinary gravity. In particular, differences in the energetics of the collapse necessitate a new, generalized method for defining the virial radius which does not rely on strict energy conservation. These differences and techniques apply to smooth dark energy models with w ≠ -1 as well. We also discuss the impact of the exterior of the perturbation on collapse quantities due to the lack of a Birkhoff theorem in DGP. The resulting predictions for the mass function, halo bias, and power spectrum are in good overall agreement with DGP N-body simulations on both the self-accelerating and normal branch. In particular, the impact of the Vainshtein mechanism as measured in the full simulations is matched well. The model and techniques introduced here can serve as practical tools for placing consistent constraints on braneworld models using observations of large-scale structure.
Rethinking the Role of Corrective Feedback in Communicative Language Teaching

The history of second language teaching has witnessed changing perceptions of corrective feedback. Under the extreme view of communicative language teaching, which appears to be prevailing in some communicatively-oriented classrooms, learning can only come about through learner-learner interactive output practice. Form- focused instruction is deemed detrimental. Corrective feedback is consequently accorded low status in classroom processes. In this paper, I examine the 'equation' drawn between communicative language teaching and the exclusion of form-focused instruction and error correction. By bringing in a cognitive-skill-acquisition perspective to bear on the role of corrective feedback in second language acquisition, I argue that in communicative language teaching, corrective feedback remains an important vehicle for facilitating L2 knowledge construction and enhancing knowledge use. Issues related to the actual provision of corrective feedback in the classroom are considered, which include matching t...