cssi/SciSciGPT-SciSciNet huggingface dataset:
BF3?OEt2-initiated polymerization of 2-methylene-1,3-dioxepanes

BF 3 .OEt 2 -initiated polymerizations of 2-methylene-1,3-dioxepane gave polymers composed of both ring-retained and ring-opened structures. The ring-opening content increased with an increase in polymerization temperature. Poly(4,7-dimethyl-2-methylene-1,3-dioxepane) propagated slower during BF 3 .OEt 2 -initiated polymerization and had a lower ring-opened content than poly( 2-methylene-1,3-dioxepane). The type of acid initiator used also affected the amount of ring opening observed. Stronger acids gave less ring opening. Attempted BF 3 .OEt 2 -initiated copolymerizations of these seven-membered ring cyclic ketene acetals with isobutyl vinyl ether at room temperature resulted in formation of the two homopolymers.
Helix-coil dynamics in RNA: the amino acid acceptor helix of Escherichia coli phenylalanine transfer RNA.

Abstract The RNA helix is a fluctuating dynamic structure in solution. In this paper we report a kinetic description of the individual base-pairs in an RNA helix (the acceptor stem of Escherichia coli tRNA Phe ) obtained by proton nuclear magnetic resonance spectroscopy using the saturation recovery techniques described by Johnston & Redfield (1977). We have determined the helix opening rates of each of the six Watson-Crick G·C base-pairs in the acceptor stem of partially unfolded E. coli tRNA Phe at elevated temperature in the presence of buffers, under which conditions saturation recovery is exchange-dominated and the exchange process is rate-limited by helix-coil opening.
Preservation of hearing among agricultural workers: a review of literature and recommendations for future research.

Agricultural workers have significant exposures to a myriad of occupational hazards on the farm. Morbidity and mortality statistics repeatedly illustrate the toll of these hazards on the thousands of farmers nationwide (NSC, 2000). Among the most common occupational diseases among farmers is noise–induced hearing loss (NIHL). Marvel (1992) estimates that approximately 328,000 farmers are exposed to potentially hazardous noise levels, especially tractor noise.
Approach to the design of discrete-time wavelets

The paper presents an approach to the design of half-band discrete-time wavelets. This is accomplished through the use of a class of quadrature mirror filters which exhibit near- perfect reconstruction property. In particular, we present a technique for the design of such filters, wherein the designer has the flexibility to make tradeoffs between in- band behavior, out-of-band behavior, and the transition-band behavior. The basic formulation is carried out in the frequency domain, which is shown to translate the design problem into an eigenvalue-eigenvector problem. To find the optimal filter for a specific set of specifications, an optimization algorithm is also presented. Using this algorithm, designs ranging from 4 to 80 taps have been carried out successfully. A fairly complete table of resulting filters, which can be used by signal and image processing engineers, is included in the paper.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
The quantitative epistemological content of Bohr's Correspondence Principle

The basic dynamical quantities of classical mechanics, such as position, linear momentum, angular momentum and energy, obtain their fundamental epistomological content by means of their intimate relationship to the symmetries of the space-time manifold which is the arena of physics. The program of canonical quantization can be understood as a two stage process. The first stage is Bohr's Correspondence Principle, whereby the basic dynamical quantities of the quantum theory are required to retain precisely the same relationship to the symmetries of the space-time manifold as do their classical counterparts, thereby preserving their epistemological, as well as measurement-theoretic, significance. Having so identified the basic dynamical variables, functions of these may now be used to identify the subtler symmetries of the proper canonical group. The second and determining stage of the quantization program requires the establishment of a correspondence between some of these subtler symmetries of the classical theory and related symmetries of the quantum theory, the relationship being determined by a common algebraic form for their defining functions.
A tripeptide sequence within the nascent DaaP protein is required for mRNA processing of a fimbrial operon in Escherichia coli.

The biogenesis of F1845 fimbriae, a member of the Dr family of Escherichia coli adhesins, is regulated by endonucleolytic cleavage of the daaABCDPE primary transcript and differential stability of the resulting cleavage products. Processing of daa mRNA is dependent upon translation of a small open reading frame, designated daaP, which flanks the daa processing site. Here, we demonstrate that daa mRNA processing is directly coupled to daaP translation. Cleavage of the daaA–E mRNA was shown to require the tripeptide Gly–Pro–Pro (GPP), encoded by daaP codons 49–51 downstream of the processing site. Processing also required active translation through RNA located upstream of the processing site; however, processing did not depend on the amino acid sequence encoded by the region of daaP upstream of the processing site. Finally, determination of the processing site was shown to involve its location relative to the codons encoding the GPP tripeptide. These data show that translation of daaP is required in cis to promote RNA processing. These data suggest a model involving interaction of the nascent GPP tripeptide portion of the DaaP polypeptide with the ribosome, triggering cleavage of the associated mRNA at a fixed distance upstream. A model of active involvement of the ribosome in this process is proposed.
Laser Photochemical Vapor Deposition

A brief overview of the status of laser photochemical vapor deposition (LPVD) will be given, with emphasis on large area processing. Recent experiments, in which chemical vapor deposition of Ge (or Si) has been "triggered" by ultraviolet (UV) laser photodissociation of GeH4 (or Si2H6), are described.
Expression of nervous system antigen-3 by lines of mouse fibroblasts and kidney cells and continued expression in hybrid cells

In a survey of the expression on cultured mouse cells of the cell surface antigen known as nervous system antigen-3 (NS-3), it was found that RAG, a renal adenocarcinoma line, expressed that antigen. It was also observed that 3T3, a fibroblast line of unknown tissue origin, expressed NS-3. Cells of these two lines were hybridized with cells of two mouse L cell lines that did not express NS-3. Four hybrid clones were tested for both the 3T3 X L cell cross and the RAG X L cell cross, and all the hybrids were found to be NS-3 positive. All the hybrids had at least 40% as much activity as the NS-3 positive parent. Of the four parental mouse cell lines used, only 3T3 expressed Thy-1.2 antigen on the cell surface. In contrast to the continued expression of NS-3 on hybrid cells, Thy-1.2 antigen was not detectable on two clones of 3T3 X L cell hybrids that were tested.
Deficient immunologic functions of NZB mice.

SummarySpleen cells from Coombs positive 480-500-day-old male NZB mice were incapable of inducing graft-versus-host reactions when injected into (NZBXA) F1 hybrids. This occurred even when the total number of nucleated cells injected was adjusted to contain 15-20 × 106 lymphoid cells. Younger, 45 and 150 day old, NZB mice were capable of inducing graft-versus-host reactions in a normal fashion.
THE IDENTITY OF OUR PROFESSION

Publisher Summary Chemical engineering, according to Frontiers in Chemical Engineering, will be governed by a new paradigm in the future. The new paradigm suggests revolutionary change, with far-reaching implications regarding education research and the practice of the profession. Chemical engineering has been experiencing gradual and predictable evolutionary change for four decades. Chemical engineering research now considers to an increasing extent, phenomena at a “micro” level, using sophisticated instrumentation that was unavailable only a few years ago. These research tools have widened the scope of potential applications, as required by the demands of the modem science-based technologies; they have required no change in the basic disciplinary matrix5 of transport and reaction rate control. It is suggested that chemical engineers do need to be more aggressive in seeking a leadership role in bringing about advances in technology. Also, chemical engineering education needs to be built around a core at the graduate as well as the undergraduate level. The core should emphasize the disciplinary matrix: the analysis of chemical and physical rate processes.
Metabolic characteristics and body composition in house finches: effects of seasonal acclimatization

House finches (Carpodacus mexicanus) from the introduced population in the eastern United States were examined to assess metabolic characteristics and aspects of body composition associated with seasonal acclimatization. Wild birds were captured during win- ter (January and February) and late spring (May and June) in southeastern Michigan. Standard metabolic rates did not differ seasonally, but cold-induced "peak" metabolic rate was 28% greater in winter than late spring. The capacity to maintain elevated metabolic rates during cold exposure ("thermogenic endurance") increased significantly from an average of 26.1 to 101.3 rain in late spring and winter, respectively. House finches captured in the late afternoon during winter had twice as much stored fat as those during late spring. Both the wet mass and lean dry mass of the pectoralis muscle, a primary shivering effector, were significantly greater during winter. The seasonal changes in peak metabolism and thermogenic endur- ance demonstrate the existence and magnitude of meta- bolic seasonal acclimatization in eastern house finches. Increased quantities of stored fat during winter appear to play a role in acclimatization, yet other physiological adjustments such as lipid mobilization and catabolism are also likely to be involved.
Herpes simplex virus 1 gene expression is accelerated by inhibitors of histone deacetylases in rabbit skin cells infected with a mutant carrying a cDNA copy of the infected-cell protein no. 0.

An earlier report showed that the expression of viral genes by a herpes simplex virus 1 mutant [HSV-1(vCPc0)] in which the wild-type, spliced gene encoding infected-cell protein no. 0 (ICP0) was replaced by a cDNA copy is dependent on both the cell type and multiplicity of infection. At low multiplicities of infection, viral gene expression in rabbit skin cells was delayed by many hours, although ultimately virus yield was comparable to that of the wild-type virus. This defect was rescued by replacement of the cDNA copy with the wild-type gene. To test the hypothesis that the delay reflected a dysfunction of ICP0 in altering the structure of host protein-viral DNA complexes, we examined the state of histone deacetylases (HDACs) (HDAC1, HDAC2, and HDAC3). We report the following. (i) HDAC1 and HDAC2, but not HDAC3, were modified in infected cells. The modification was mediated by the viral protein kinase U(S)3 and occurred between 3 and 6 h after infection with wild-type virus but was delayed in rabbit skin cells infected with HSV-1(vCPc0) mutant, concordant with a delay in the expression of viral genes. (ii) Pretreatment of rabbit skin cells with inhibitors of HDAC activity (e.g., sodium butyrate, Helminthosporium carbonum toxin, or trichostatin A) accelerated the expression of HSV-1(vCPc0) but not that of wild-type virus. We conclude the following. (i) In the interval in which HSV-1(vCPc0) DNA is silent, its DNA is in chromatin-like structures amenable to modification by inhibitors of histone deacetylases. (ii) Expression of wild-type virus genes in these cells precluded the formation of DNA-protein structures that would be affected by either the HDACs or their inhibitors. (iii) Since the defect in HSV-1(vCPc0) maps to ICP0, the results suggest that this protein initiates the process of divestiture of viral DNA from tight chromatin structures but could be replaced by other viral proteins in cells infected with a large number of virions.
Nisin induces changes in membrane fatty acid composition of Listeria monocytogenes nisin‐resistant strains at 10°C and 30°C

Listeria monocytogenes isolates resistant to 10(5) IU ml-1 nisin were obtained at 30 degrees C (NR30) and at 10 degrees C (NR10). Nisin prolonged the lag phase of isolate NR30 at 10 degrees C. Isolates NR30 and NR10 did not produce a nisinase. Protoplasts of isolate NR30 were unaffected by exposure to nisin. The fatty acid composition from the wild-type strain and NR isolates was determined. As expected, temperature-induced differences in the C15/C17 fatty acid ratios were found. Growth of the NR strains in the presence of nisin resulted in significantly different C15/C17 ratios and a significant increase in the percentage of C16:0, C16: 1, C18:0 and C18: 1 fatty acids at 10 degrees C and 30 degrees C. Both the NR10 and NR30 isolates had similar growth rates at low temperatures, but these were slower than the wild-type strain. These results indicate that 'nisin resistance' is an environmentally defined phenotype and that nisin induces changes in the fatty acid composition of the membrane in L. monocytogenes nisin-resistant isolates regardless of the growth temperature.
How big should transit be? Evidence on the benefits of reorganization from the San Francisco Bay Area

This paper studies whether the many public urban transit providers in the San Francisco Bay Area could realize cost economies by consolidating into larger systems. In this discussion, any benefits of rationalization are excluded, since these could be achieved without organizational changes.
Study of Damage Engineering—Quantitative Scatter Defect Measurements of Ultralow Energy Implantation Doping Using the Continuous Anodic Oxidation Technique/Differential Hall Effect

The continuous anodic oxidation technique/differential Hall effect technique is used to study damage engineering of ultralow energy doping. It has been found that the scattering defect concentrations of the beam-line (BL) implants strongly correlate to the implant ion specie atomic mass unit and energy. Plasma doping (PLAD) seems to show a different mechanism for scatter defects. PLAD processes can have an in situ B-deposited film during implant and have less direct ion bombardment on the Si surface. The low scattering defect concentrations of PLAD implants (B2H6 and BF3) indicate that PLAD implants show an intrinsic advantage over BL counterparts in the current process regime.
Suspended‐load fallout rate as an independent variable in the analysis of current structures

The dynamic interpretation of most current-structure sequences derives directly from experiments on the succession of bedforms produced by flows in flumes. The results of these and related studies have been used to construct stability field diagrams in which the fields of individual bedforms are usually expressed as a function of flow intensity (power, velocity, bed shear stress, etc.) and grain size. The data underlying existing stability-field diagrams were collected largely from the study of flows carrying coarse-grained sediment entrained through particle-by-particle bed erosion. Many flows, however, do not entrain sediment through simple bed erosion. Most turbidity currents originate by the development of turbulence in slumps, slides, and other slope failures. Such flows generally form with highly concentrated suspended loads and their bed-load layers derive sediment from the collapsing suspended-sediment clouds. Because the collapse properties of such clouds may be related as much to suspended particle concentration, size distribution, particle interactions, and other factors as to flow intensity, the stability fields of bedforms developed beneath such flows may differ in flow intensity-grain-size relationships from those beneath flows deriving sediment from bed erosion alone. Useful stability-field diagrams for turbidity currents must include suspended-load fallout rate as a third variable, independent of flow intensity and mean grain size. A preliminary stability-field diagram of this type indicates that Bouma Tabc sequences may theoretically form with essentially no velocity variation of the attendant flow. This type of analysis may have considerable relevance to the interpretation not only of turbidites but also of other deposits formed where bed-load layers are fed from above rather than below. These include shallow-shelf storm units deposited from highly concentrated flows and volcaniclastic layers formed where pyroclastic debris falls directly into moving water.
Psychometric Properties of the Therapeutic Alliance Scale for Caregivers and Parents

This study examined the psychometric properties of the Therapeutic Alliance Scale for Caregivers and Parents (TASCP) in a sample of 209 caregivers whose children (4-13 years of age) presented with disruptive behavior problems to a publicly funded outpatient mental health clinic in San Diego County. Information about therapeutic alliance was collected from caregivers, children, and their therapists across the course of therapy (up to 16 months). Results support the reliability, temporal stability, convergent validity, and discriminant validity of scores on the TASCP. The multilevel factor structure of this new measure was consistent with the parallel child-report version, with 2 within-level factors and 1 between-level factor. Furthermore, predictive validity was strong, with stronger caregiver-reported alliance associated with less treatment dropout, more sessions attended, and greater satisfaction with perceived improvement.
The medium and high energy optical model and the correlations in the nuclear wave function

Abstract Watson's multiple scattering theory is applied to calculate the well depths of the nuclear optical potential for the case of strongly correlated nuclear matter. The nuclear ground state is represented by a Jastrow type wave function. The consequences of the Bethe-Goldstone equation for the correlation functions are considered. Our numerical results obtained for the case of a separable nucleon-nucleon interaction show that the effects of the correlations amount to corrections to the Fermi model case up to the order of 10 per cent in the medium and high energy range. The evaluated corrections due to the incoherent multiple scattering appear to be important.
SME Internet use and strategic flexibility: the moderating effect of IT market orientation

Abstract One of the most important topics in the marketing literature has been the concept of market orientation. However, questions remain as to the dynamics of how market orientation translates into intermediate capabilities. This study explores relationships among different types of Internet usage, IT market orientation (the extent to which IT is aligned to manage customer and competitor information and internal activities), and strategic flexibility (firm capability to respond to the need for change). Specifically, use of the Internet for communication with relevant stakeholders, owing to its market-sensing potential, should be positively and significantly related to strategic flexibility for SMEs with more IT market-oriented alignment. The market-sensing potential of Internet communication to impact strategic flexibility positively for SMEs is likely to be lost under low IT market-oriented-alignment conditions. In contrast, IT market orientation should not moderate the relationship between Internet u...
Mirror reflectivities from 50–150 eV

Abstract An accurate reflectometer has been set up on the 2.2 m monochromator at the NBS SURF-II synchrotron radiation facility to determine optical constants of materials from 50–150 eV. Properties of the monochromator, reflectometer and NBS windowless photodiode detector are discussed. Reflectivity data from 7–30 nm for two low expansion materials, a recrystallized glass (A) and a high silica glass (B), are reported and preliminary optical constants for one glass are presented.
Turning Housing Into Driving: Parking Requirements and Density in Los Angeles and New York

This article examines the idea that residential minimum parking requirements are associated with lower housing and population densities and higher vehicle densities (residential vehicles per square mile). Cities frequently use minimum parking requirements to manage traffic, but parking requirements accommodate vehicles, suggesting they should lead to more driving and congestion rather than less. If parking requirements reduce congestion, they likely do so not by reducing the number of vehicles in an area but by reducing the densities of housing and people. We support this idea by comparing the Los Angeles and New York urbanized areas. We show that differences in housing, vehicle, and population densities across and within these urbanized areas are closely correlated with differences in the share of housing units that include parking, and that the share of housing units that include parking is in turn correlated with the stringency of parking requirements. Compared with Los Angeles, New York shifts less of...
Transosseous transposition of a pedicled rectus abdominis flap to cover hip wounds

Bone-marrow transplantation may be complicated by aseptic necrosis of the femoral head. Prolonged immunosuppression places the patient at increased risk of infection and is of particular concern if replacement arthroplasty is contemplated. Infection of a prosthesis usually requires thorough debridement and removal of the device. However, attention must also be paid to the resultant cavity and soft-tissue cover. Several flaps have been reported for this problem, though limitations of flap size may make it difficult to achieve both objectives. This report describes the use a pedicled rectus abdominis flap that was tunnelled through the acetabulum in order to gain direct access to the hip and allow adequate length both to fill the dead-space and to provide cover.
Antiarrhythmic Actions of Amiodarone: A Profile of a Paradoxical Agent

Amiodarone, a complex compound with variegated electropharmacologic and pharmacokinetic properties and an equally complex side-effect profile, continues to have a critical role in the control of ventricular and supraventricular tachyarrhythmias as the use of class I agents has declined. Such is also the case with sotalol. Unlike other so-called class III agents, amiodarone non-competitively blocks sympathetic stimulation, and its effects on repolarization are not associated with reverse use dependency. Rarely does it produce torsades de pointes despite its propensity to induce significant bradycardia and marked prolongation of the QT interval. During long-term therapy with the drug, there is no impairment of ventricular function; in fact, there are significant increases in the left ventricular ejection fraction during protracted amiodarone therapy in patients with heart failure. Long-term amiodarone administration consistently demonstrates marked efficacy in a wide spectrum of arrhythmias. The major limitation of amiodarone during long-term therapy is its unusual side-effect profile, although the increasing trend for low-dose drug therapy has demonstrated a major decline in the overall incidence of serious adverse reactions. Amiodarone is effective in controlling symptomatic ventricular tachycardia and fibrillation (VT/VF) in > 60-70% of patients when conventional agents (especially class I) are ineffective or not well tolerated. The efficacy of amiodarone compared with that of an implantable cardioverter-defibrillator in patients with VT/VF and in survivors of cardiac arrest remains uncertain when total mortality is used as the primary endpoint of comparison. Amiodarone suppresses ventricular ectopy and markedly suppresses nonsustained VT. It prevents inducible VT/VF in a small number of patients, but slows VT rate in a larger number. The role of the drug in prolonging survival in the postmyocardial infarction patient is unclear, although preliminary data from blinded studies suggest that the drug decreases arrhythmia-related mortality. Similarly, in heart failure, amiodarone has the potential to reduce total mortality but appears to be selectively effective in nonischemic rather than in ischemic cardiomyopathy. Intravenous amiodarone was recently introduced in the United States for the control of recurrent destabilizing VT or VF resistant to conventional therapy. There is also evolving data indicating that the drug might be the most potent agent in maintaining sinus rhythm in patients with atrial fibrillation or flutter converted chemically or electrically to sinus rhythm. However, blinded controlled comparative studies involving sotalol, quinidine, or pure class III drugs have not been carried out. The available data nevertheless suggest that, barring its side-effect profile, amiodarone is a desirable prototype of a broad-spectrum antifibrillatory and antiarrhythmic compound.
Blast Performance of Marine Foam Core Sandwich Composites at Extreme Temperatures

The dynamic behavior of sandwich composites for marine applications, made of E-glass Vinyl Ester skin and Corecell™ M100 foam core material, was studied at different temperatures using a shock tube apparatus. High-speed photography coupled with the optical technique of Digital Image Correlation was used to record the real time deformation of the specimen during shock wave loading. Sandwich composites under a high temperature environment demonstrated a significant amount of fiber breakage, fiber-matrix delamination as well as core compression when subjected to a shock wave loading. When subjected to low temperature environment and shock loading, the core material showed brittle behavior resulting in core-cracking in the sandwich composite. The dynamic response and failure mechanisms demonstrated by the sandwich composites at these temperatures were in correspondence with the high strain rate behavior of the individual constituents.
Nef and PAK: virulence factor and cellular accomplice

The Nef protein is important in HIV replication and in AIDS pathogenesis. The finding that Nef activates a member of the PAK family of protein kinases provides new insights into the mechanisms of action of this critical virulence factor.
Convergence Properties of Higher Order Modeling of Cylindrical Wire Kernel

Recent research has proposed new techniques to analyze the cylindrical wire kernel accurately. These techniques assume a circumferentially invariant surface current distribution. Such an approximation is valid for cases where the wire diameter is very small compared to the wavelength and can be used to model wire structures by using higher order bases. This paper performs a higher order analysis of wire antennas using the method of moments (MoM) and examines the variation in error convergence with wire thickness. Numerical results show that fast convergence can be achieved with these bases up to the point where circumferential variations are important
Redundancy in the pathway for redox regulation of mammalian methionine synthase: reductive activation by the dual flavoprotein, novel reductase 1.

Abstract Methionine synthase is an essential cobalamin-dependent enzyme in mammals that catalyzes the transfer of a methyl group from methyltetrahydrofolate to homocysteine to give tetrahydrofolate and methionine. It is oxidatively labile and requires for its sustained activity an auxiliary repair system that catalyzes a reductive methylation reaction. Genetic and biochemical studies have demonstrated that the soluble dual flavoprotein oxidoreductase, methionine synthase reductase, serves as a redox partner for methionine synthase in an NADPH-dependent reaction. However, three reports suggest the possibility of redundancy in this redox pathway. First, a hyperhomocysteinemic patient has been reported who has an isolated functional deficiency of methionine synthase but appears to be distinct from the cblE and cblG classes of patients with defects in methionine synthase reductase and methionine synthase, respectively. Second, another dual flavoprotein oxidoreductase with significant homology to methionine synthase reductase, NR1, has been described recently, but its function is unknown. Third, methionine synthase can be activated in vitro by a two-component redox system comprised of soluble cytochrome b5 and P450 reductase. In this study, we demonstrate a function for human NR1 in vitro. It is able to fully activate methionine synthase in the presence of soluble cytochrome b5 with a Vmax of 2.8 ± 0.1 μmol min–1 mg–1 protein, which is comparable with that seen with methionine synthase reductase. The KactNR1 is 1.27 ± 0.16 μm, and a 20-fold higher stoichiometry of reductase to methionine synthase is required for NR1 versus methionine synthase reductase, suggesting that it may represent a minor pathway in the cell, assuming that the two proteins are present at similar levels.
A research approach to institutional alternatives in the administration of agrarian development programmes

Large-scale development project implementation requires the delivery ana coordination of several inputs. Often, these inputs are under the control of separate agencies. A model to guide empirical testing of alternative institutional structures is developed and applied to a case study. Alternatives include a coordinating forum, a planning agency and versions of a consolidated, centralised super agency. The model emphasises variables which affect the bargaining power of a project initiator in obtaining the cooperation of other parties.
The real-space multiple-scattering theory and the electronic structure of grain boundaries

We describe the recently developed real-space multiple-scattering theory (RSMST), which is designed for performing first-principles electronic-structure calculations of extended defects, such as surfaces and interfaces including atomic relaxations and with or without impurities, without using artificial periodic boundary conditions. We present the results of non-charge-selfconsistent RSMST calculations of the local electronic densities of states at twist and tilt grain boundaries in fcc Cu and bcc Nb, and report on progress towards the implementation of charge self-consistency and total-energy capabilities.
Temporal coherence sensitivity in auditory cortex.

Natural sounds often contain energy over a broad spectral range and consequently overlap in frequency when they occur simultaneously; however, such sounds under normal circumstances can be distinguished perceptually (e.g., the cocktail party effect). Sound components arising from different sources have distinct (i.e., incoherent) modulations, and incoherence appears to be one important cue used by the auditory system to segregate sounds into separately perceived acoustic objects. Here we show that, in the primary auditory cortex of awake marmoset monkeys, many neurons responsive to amplitude- or frequency-modulated tones at a particular carrier frequency [the characteristic frequency (CF)] also demonstrate sensitivity to the relative modulation phase between two otherwise identically modulated tones: one at CF and one at a different carrier frequency. Changes in relative modulation phase reflect alterations in temporal coherence between the two tones, and the most common neuronal response was found to be a maximum of suppression for the coherent condition. Coherence sensitivity was generally found in a narrow frequency range in the inhibitory portions of the frequency response areas (FRA), indicating that only some off-CF neuronal inputs into these cortical neurons interact with on-CF inputs on the same time scales. Over the population of neurons studied, carrier frequencies showing coherence sensitivity were found to coincide with the carrier frequencies of inhibition, implying that inhibitory inputs create the effect. The lack of strong coherence-induced facilitation also supports this interpretation. Coherence sensitivity was found to be greatest for modulation frequencies of 16-128 Hz, which is higher than the phase-locking capability of most cortical neurons, implying that subcortical neurons could play a role in the phenomenon. Collectively, these results reveal that auditory cortical neurons receive some off-CF inputs temporally matched and some temporally unmatched to the on-CF input(s) and respond in a fashion that could be utilized by the auditory system to segregate natural sounds containing similar spectral components (such as vocalizations from multiple conspecifics) based on stimulus coherence.
Impact of Ultra-Sensitive technology and contemporary therapy on laboratory results.

The introduction of ultra-sensitive labels for immunoassays has exposed some of the limitations inherent in them. Thus, for instance a major problem with acridinium esters used, as chemiluminescence label is the formation of the so called “pseudobases” at an alkaline pH, which if not suppressed can affect the rate of the chemiluminescence reaction. Chemiluminescence labels such as luminol can also be problematic when attached to antibodies and small molecules to the extent that the sensitivity of the assay can be reduced by the decrease in the intensity of chemiluminescence. The increased use of molecular methods such as polymerase chain reaction (PCR) and post PCR methods to study mutations have various pittalls, which if unrecognized and uncontrolled can lead to incorrect results and misinterpretation. Patients who are exposed to mouse immunoglobulins through imaging or therapeutic techniques can develop antibodies to mouse immunoglobulins (human anti-mouse antibodies or HAMA) which can be a major problem for non optimized immunoassays using murine monoclonal antibodies. The types of therapy such as anticoagulant used in anticoagulant therapy, blood substitute and drug therapy can impact on the measurements of some of the biochemical and other analytes. One must separate the transient, physiological effects introduced by therapy from long-term biochemical alterations due to disease.
President's Message for 1968

The article discusses the plans of the Academy of Management in 1968, announcing that Paul Gordon was appointed as president-elect and Joseph Litterer as vice-president. The author states that he h...
Interactive effects of solutes, potassium sorbate and incubation temperature on growth, heat resistance and tolerance to freezing of Zygosaccharomyces rouxii

The interactive effects of solutes, potassium sorbate and incubation temperature on growth, heat resistance and tolerance to freezing of Zygosaccharomyces rouxii were investigated. Growth rates in media supplemented with glucose, sucrose or NaCl to aw 0.93 were more rapid than in unsupplemented media (aw 0.99). Although growth in unsupplemented medium was lower at 35 degrees C, incubation at 21 degrees C or 35 degrees C had little effect on growth in media supplemented with glucose and sucrose. The addition of 300 micrograms potassium sorbate/ml to media resulted in reduced growth rates, particularly at 35 degrees C. Heat resistance of Z. rouxii was substantially greater in cultures previously incubated at 35 degrees C than in cultures incubated at 21 degrees C in media both with and without 300 micrograms potassium sorbate/ml. Zygosaccharomyces rouxii was tolerant to freezing at -18 degrees C for up to 120 d in all test media supplemented with glucose, sucrose or NaCl. The addition of 300 micrograms potassium sorbate/ml to sucrose-supplemented media resulted in increased resistance to freezing in cultures previously incubated at 21 degrees C. Sensitivity to freezing increased when cultures were incubated at 21 degrees C in media not supplemented with solutes. Glucose and sucrose provided the best protection against inactivation by heating and freezing, regardless of the presence of potassium sorbate in growth media.
Operant generalization of auditory tempo in quail neonates.

Operant generalization, a building block of cognition, has never been studied in neonates. We developed a preparation for newly hatched quail in order to investigate the form of the generalization gradient very early in development. For their first 4–5 days after hatching, northern bobwhite chicks pecked for brief heat presentations while hearing a high-pitched sound repeated at a constant rate (nondifferential training). Tempo generalization was then assessed in extinction. A significantly excitatory average gradient resulted despite minimal postnatal experience.
Longitudinal associations between depressive and anxiety disorders: a comparison of two trait models.

BackgroundDepression and anxiety are highly co-morbid disorders. Two latent trait models have been proposed to explain the nature of the relationship between these disorders. The first posits that depressive and anxiety disorders are both manifestations of a single internalizing factor. The second model, based on a tripartite model proposed by Clark & Watson [Journal of Abnormal Psychology (1991) 100, 316–336], proposes that depressive and anxiety disorders reflect a combination of shared and disorder-specific factors.MethodWe directly compared the two models in a sample of 891 individuals from the Oregon Adolescent Depression Project who participated in up to four diagnostic assessments over approximately 15 years. Structural equation models were used to examine the relationship between depressive and anxiety disorders across different developmental periods (<14, 14–18, 19–23, 24–30 years of age).ResultsThe one- and three-factor models were hierarchically related. Thus, a direct comparison between the one- and three-factor models was possible using a χ2 difference test. The result found that the three-factor model fit the data better than the one-factor model.ConclusionsThe three-factor model, positing that depressive and anxiety disorders were caused by a combination of shared and disorder-specific factors, provided a significantly better fit to the data than the one-factor model postulating that a single factor influences the development of both depressive and anxiety disorders.
Nitrogen fixation in freshwater, estuarine, and marine ecosystems. 2. Biogeochemical controls1

Planktonic nitrogen fixation in lakes is strongly related to lake trophic status, with moderate and high rates usually occurring only in eutrophic lakes. Among eutrophic lakes, nitrogen fixation is related to the ratio of nitrogen loading to phosphorus loading to the lake; significant nitrogen fixation by planktonic organisms generally occurs only when the N: P ratio of the nutrient loading is near or below the Redfield ratio of 16: 1. In contrast, nitrogen fixation by planktonic organisms is generally low in estuaries even when the N: P ratio of nutrients inputs is low. The tendency toward less nitrogen fixation by plankton in estuaries and coastal marine ecosystems than in lakes subject to similar loadings of nitrogen and phosphorus may be due to a lower availability in oxic seawater of one or more trace elements required for nitrogen fixation, such as molybdenum and iron. Iron concentrations are generally lower in estuarine waters and seawater than in most lakes. And although molybdenum concentrations in seawater are actually higher than in lakes, molybdenum availability is probably lower, since sulfate inhibits molybdate assimilation by microbes. Molybdate is the primary form of molybdenum in oxic seawater, and the ratio of sulfate: molybdate is greater than in lakes. However, even in lakes sulfate is several orders of magnitude more abundant than molybdenum, and the ratio of dissolved sulfate to dissolved molybdenum typically is much greater than the ratio of sulfur to molybdenum apparently required by nitrogen-fixing cyanobacteria. Consequently, assimilation of molybdate by cyanobacteria is probably an energetically expensive process in all natural waters, but more so in seawater than in freshwaters. High concentrations of dissolved organic matter are known to favor blooms of cyanobacteria, perhaps by increasing iron and/or molybdenum availability through chelation. The primary controls on nitrogen fixation in sediments, wetlands, macrophyte beds, and cyanobacterial mats may be different from those for fixation by planktonic organisms. Both molybdenum and iron are probably more available in these systems than in oxic waters, since reducing conditions and high DOC concentrations will increase iron solubility and favor the stability of reduced forms of molybdenum; sulfate should not inhibit the assimilation of these reduced molybdenum compounds. Consequently, nitrogenase synthesis (and, therefore, nitrogen fixation) in wetlands and in sediments may be less energetically expensive than in oxic water columns. A major control on nitrogen fixation in sediments may be repression of nitrogenase synthesis by high concentrations of ammonium, a factor less important to planktonic fixation because of the much lower concentrations of ammonium generally found in water columns than in sediments.
G3139 (oblimersen) may inhibit prostate cancer cell growth in a partially bis-CpG-dependent non-antisense manner

G3139 is an 18-mer phosphorothioate oligodeoxyribonucleotide, which is targeted to the initiation codon region of the bcl -2mRNA. Although treatment of PC3 prostate cancer cells with G3139, which contains two CpG motifs, causes a dramatic decrease in bcl -2 protein expression after 3 days, it did not result in significant cellular apoptosis, as it does in many other cell lines. The absence of apoptosis was demonstrated by the absence of pro-caspase 3 cleavage products and of Annexin V cell surface expression. In addition, ATP production and the mitochondrial membrane potential Δ Ψ m were preserved. Despite this, G3139 significantly inhibited the rate of cellular proliferation in complete media and blocked cloning in soft agar. G4232, a variant of G3139 that down-regulates bcl -2 expression to the same extent but has both CpG cytidines C5 methylated, was only minimally antiproliferative. A series of mismatched G3139-related oligomers were synthesized that could also substantially down-regulate bcl -2 protein expression, but only if the CpG motifs were preserved, demonstrating the presence of additional non-antisense mechanisms. G3139 caused production of reactive oxygen species in growth-arrested cells and oxidation of nuclear guanosine to 8-hydroxy-2′-deoxyguanosine, as determined by 1F7 monoclonal antibody staining. Bromodeoxyuridine incorporation studies demonstrated that G3139 induced a G1-S entry block and an intra-S-phase block in PC3 cells that persisted as long as 3 days. This finding coincides with the observation that expression of several proteins encoded by S-phase genes, including c- myb and poly(ADP-ribose) polymerase, were significantly reduced. These results illustrate the complexity of the mechanism of action of G3139 in PC3 cells.
Monte Carlo simulation methods for dynamic line layout problems with nonlinear movement costs

Monte Carlo simulation provides a risk management tool for solving line layout problems when material flow requirements change over time and/or are uncertain. This study demonstrates this capability for line layout problems where material handling costs are not directly proportional to the distance travelled, e.g., where individual material moves impose a fixed cost which is amortised over the length of the move. Nonlinear movement costs are modelled using a movement 'discount factor' embedded in a Monte Carlo simulation model that is used to identify solutions performing at high, although not necessarily optimal, levels across a range of operating conditions. The procedure is demonstrated through a series of sample problems. [Received 09 September 2008; Revised 26 November 2008; Accepted 01 December 2008]
Ontogenetic investigation of underwater hearing capabilities in loggerhead sea turtles (Caretta caretta) using a dual testing approach

Sea turtles reside in different acoustic environments with each life history stage and may have different hearing capacity throughout ontogeny. For this study, two independent yet complementary techniques for hearing assessment, i.e. behavioral and electrophysiological audiometry, were employed to (1) measure hearing in post-hatchling and juvenile loggerhead sea turtles Caretta caretta (19–62 cm straight carapace length) to determine whether these migratory turtles exhibit an ontogenetic shift in underwater auditory detection and (2) evaluate whether hearing frequency range and threshold sensitivity are consistent in behavioral and electrophysiological tests. Behavioral trials first required training turtles to respond to known frequencies, a multi-stage, time-intensive process, and then recording their behavior when they were presented with sound stimuli from an underwater speaker using a two-response forced-choice paradigm. Electrophysiological experiments involved submerging restrained, fully conscious turtles just below the air–water interface and recording auditory evoked potentials (AEPs) when sound stimuli were presented using an underwater speaker. No significant differences in behavior-derived auditory thresholds or AEPderived auditory thresholds were detected between post-hatchling and juvenile sea turtles. While hearing frequency range (50–1000/1100 Hz) and highest sensitivity (100–400 Hz) were consistent in audiograms pooled by size class for both behavior and AEP experiments, both post-hatchlings and juveniles had significantly higher AEP-derived than behavior-derived auditory thresholds, indicating that behavioral assessment is a more sensitive testing approach. The results from this study suggest that post-hatchling and juvenile loggerhead sea turtles are low-frequency specialists, exhibiting little differences in threshold sensitivity and frequency bandwidth despite residence in acoustically distinct environments throughout ontogeny.
The design of multiplierless two-channel linear-phase FIR filter banks with applications to image subband coding

An optimization technique is presented for the design of multiplierless two-channel linear-phase finite impulse response (FIR) filter banks which yield good filtering performance and nearly perfect signal reconstruction. The filter coefficients are represented by a canonic signed-digit (CSD) code. When applied to image subband coding, this technique provides an easy way to design low-complexity analysis/synthesis filter banks for high-performance codecs. Examples concerning the design of filters and the application to image subband coding are given. >
Science to Practice: Is T2* Enough to Assess Oxygenation?

The blood oxygen level–dependent (BOLD) signal is affected by many more tissue parameters than O2 alone, including spin density, T2, blood volume fraction, and hematocrit; just as oxygen saturation can vary between different tissues, so may these additional MR parameters affecting the BOLD signal.