cssi/SciSciGPT-SciSciNet huggingface dataset:
Gravitational radiation from supernova neutrino bursts

SUPERNOVAE, the violent collapses of massive stars into neutron stars, are considered to be the strongest known sources of gravitational radiation. The quadrupole (and higher) moments of the hydrodynamic motions of the infalling matter generate the radiation. A burst of neutrinos of total energy ∼0.1 M⊙c2 and of duration between ∼10−3 and 1 s is thought to accompany the collapse1. If this burst has nonspherical angular distribution, it will generate additional gravitational radiation— possibly comparable in magnitude to that caused by the collapse. That the neutrino burst might produce gravitational waves had been overlooked until recently, when Epstein suggested the idea2. This problem is of interest in its own right because a massless field is acting as the source of a radiation field. In electromagnetism there are no charged, massless particles; in fact, the existence of such a particle would lead to infrared divergences3. The gravitational effects of neutrinos have been studied previously2,4–6, but the approach we report here is new and has a nice analogue in electromagnetism. The emission of a neutrino is a quantum process and so we use the zero frequency limit (ZFL) quantum technique of Weinberg3 to obtain a classical source which gives correct results in this limit. Because the time scale of the burst (∼10−3–1 s) is much longer than that of the neutrino emission process (∼10−22 s) only the ZFL is needed in the calculation. The ZFL technique has been used in an analogous way in electromagnetism to calculate the electromagnetic radiation accompanying β-decay or electron capture7. Smarr has applied the ZFL method to the gravitational bremsstrahlung process8.
What role for biologically based dose-response models in estimating low-dose risk?

BACKGROUND: Biologically based dose-response (BBDR) models can incorporate data on biological processes at the cellular and molecular level to link external exposure to an adverse effect. OBJECTIVES: Our goal was to examine the utility of BBDR models in estimating low-dose risk. METHODS: We reviewed the utility of BBDR models in risk assessment. RESULTS: BBDR models have been used profitably to evaluate proposed mechanisms of toxicity and identify data gaps. However, these models have not improved the reliability of quantitative predictions of low-dose human risk. In this commentary we identify serious impediments to developing BBDR models for this purpose. BBDR models do not eliminate the need for empirical modeling of the relationship between dose and effect, but only move it from the whole organism to a lower level of biological organization. However, in doing this, BBDR models introduce significant new sources of uncertainty. Quantitative inferences are limited by inter- and intraindividual heterogeneity that cannot be eliminated with available or reasonably anticipated experimental techniques. BBDR modeling does not avoid uncertainties in the mechanisms of toxicity relevant to low-level human exposures. Although implementation of BBDR models for low-dose risk estimation have thus far been limited mainly to cancer modeled using a two-stage clonal expansion framework, these problems are expected to be present in all attempts at BBDR modeling. CONCLUSIONS: The problems discussed here appear so intractable that we conclude that BBDR models are unlikely to be fruitful in reducing uncertainty in quantitative estimates of human risk from low-level exposures in the foreseeable future. Use of in vitro data from recent advances in molecular toxicology in BBDR models is not likely to remove these problems and will introduce new issues regarding extrapolation of data from in vitro systems.
Cerebrocortical Microdysgenesis with Anomalous Callosal Connections: A Case Study in the Rat

A spontaneously occurring area of cerebrocortical microdysgenesis, resembling microgyria, and having its origin during development was noted in the left auditory cortex of a rat which had received a callosal section in adult life. Adjoining sections were prepared with cresyl violet for visualization of cell bodies, and by the Fink-Heimer method for degenerating axonal terminals. The microdysgenetic region was characterized by fused molecular layers containing ectopic neurons and by abnormal cortical lamination. The architecture of terminal degeneration of callosal axons within this region was abnormal with a notable absence of the usual lamination pattern and the presence instead of dense terminations in what would normally be layers I-IV and in connecting bridges running across layer V. Abnormal developmental processes that might account for the anomalous projection patterns in cortical malformations are discussed in the light of knowledge about normal corticogenesis. The behavioral implications for some childhood learning disorders are also considered.
A high-speed correlator

The correlation function, $\phi_{ij}^{(\tau)} = \lim_{T \rightarrow \infty} {1 \over T} \int^{T}_{o} f_{i}(t)f_{j}(t-\tau) dt$ is of great interest today because of its use in the fields of oceanography and meteorology and because of its recent applications in the field of communication. Various machines, both analog and digital, have been designed for the automatic computation of correlation functions. The machine described in this paper differs from those which have previously been described in the literature in that the speed with which it computes the integral above for each value of τ i is mainly limited by the minimum value of T permissible for a precision of a few per cent.
Combined research and curriculum development of nontraditional manufacturing

Nontraditional manufacturing (NTM) is becoming increasingly important in modern engineering. Therefore, it is important to develop up-to-date pedagogic materials for the area. This paper reports collaborative efforts among three universities in such a development sponsored by National Science Foundation of USA. The features of the development include systematic introduction, recent research results, and web implementation with interactive capabilities. This paper is based on an extensive web based course with animations, including Java applets, Shockwave animations, VRML animations, and QuickTime movies. The development is aimed at upper level undergraduate and introductory graduate students. Areas of focus include Laser Material Processing, Electrical Discharge Machining, Electro-Chemical Machining, and Abrasive Water Jet Machining. Cross process innovation are also presented. Needs for further pedagogic developments are discussed.
Relationships among the slopes of lines derived from various data analysis techniques and the associated correlation coefficient

A technique for fitting a straight line to a collection of data points is given. The relationships between the slopes and correlation coefficients, and between the corresponding standard deviations and correlation coefficient are given.
Intestinal absorption of calcium and calcium metabolism in patients with essential hypertension and normal renal function.

Several abnormalities of calcium metabolism have been described in patients with essential hypertension, and they have been linked to the pathogenesis of hypertension. Intestinal calcium absorption has been shown to be decreased in rats with spontaneous hypertension, but it has not been studied in patients with essential hypertension. In these studies we have for the first time measured intestinal absorption of calcium (using oral and intravenous administration of 47Ca), along with other parameters of calcium metabolism, in 14 patients with essential hypertension and normal renal function and in 16 normal subjects. There was no difference in serum total or ionized calcium, serum phosphorus, parathyroid hormone (PTH), 25-hydroxyvitamin D (25(OH)D), 1,25-dihydroxyvitamin D (1,25(OH)2D), and 24,25-dihydroxy-vitamin D(24,25(OH)2D) among hypertensives and normotensives. The urinary excretion of calcium, on the other hand, was greater in hypertensive than in normotensive subjects (195 +/- 33 v 107 +/- 13 mg/24 h, P less than .05). There was also no difference in intestinal absorption of calcium after 2 and 24 h among hypertensives and normotensives. When hypertensive patients were stratified according to plasma renin activity (PRA) we found that patients with low PRA had higher intestinal absorption of calcium at 2 h (23 +/- 2.9 v 18 +/- 0.6%, P less than .05) but not at 24 h. Serum total and ionized calcium, PTH, and 1,25(OH)2D were not different between patients with low and those with normal-high PRA. The major derangement of calcium metabolism in patients with essential hypertension is hypercalciuria. This abnormality is more pronounced in patients with low PRA, and it may lead to increased vitamin D-dependent intestinal absorption of calcium.
Prospects for replacement of auditory neurons by stem cells

Sensorineural hearing loss is caused by degeneration of hair cells or auditory neurons. Spiral ganglion cells, the primary afferent neurons of the auditory system, are patterned during development and send out projections to hair cells and to the brainstem under the control of largely unknown guidance molecules. The neurons do not regenerate after loss and even damage to their projections tends to be permanent. The genesis of spiral ganglion neurons and their synapses forms a basis for regenerative approaches. In this review we critically present the current experimental findings on auditory neuron replacement. We discuss the latest advances with a focus on (a) exogenous stem cell transplantation into the cochlea for neural replacement, (b) expression of local guidance signals in the cochlea after loss of auditory neurons, (c) the possibility of neural replacement from an endogenous cell source, and (d) functional changes from cell engraftment.
Artificial Nutrition and Hydration in Catholic Healthcare: Balancing Tradition, Recent Teaching, and Law

Roman Catholics have a long tradition of evaluating medical treatment at the end of life to determine if proposed interventions are proportionate and morally obligatory or disproportionate and morally optional. There has been significant debate within the Catholic community about whether artificially delivered nutrition and hydration can be appreciated as a medical intervention that may be optional in some situations, or if it should be treated as essentially obligatory in all circumstances. Recent statements from the teaching authority of the church have attempted to clarify this issue, especially for those with a condition known as the persistent vegetative state. I argue that these recent teachings constitute a "general norm" whereby artificial nutrition and hydration are considered obligatory for most patients, but that these documents allow for exception in cases of complication from the means used to deliver nutrition and hydration, progressive illness, or clear refusal of such treatment by patients. While the recent clarifications do not constitute a major deviation from traditional understanding and will rarely conflict with advance directives or legal statutes, there may be rare instances in which remaining faithful to church teaching may conflict with legally enshrined patient prerogatives. Using the Texas Advance Directives Act as an example, I propose ways in which ethics committees can remain faithful to their Roman Catholic identity while respecting patient autonomy and state law pertaining to end of life health care.
Familial Amyotrophic Lateral Sclerosis Mutants of Copper/Zinc Superoxide Dismutase Are Susceptible to Disulfide Reduction

We observed that 14 biologically metallated mutants of copper/zinc superoxide dismutase (SOD1) associated with familial amyotrophic lateral sclerosis all exhibited aberrantly accelerated mobility during partially denaturing PAGE and increased sensitivity to proteolytic digestion compared with wild type SOD1. Decreased metal binding site occupancy and exposure to the disulfide-reducing agents dithiothreitol, Tris(2-carboxyethyl)phosphine (TCEP), or reduced glutathione increased the fraction of anomalously migrating mutant SOD1 proteins. Furthermore, the incubation of mutant SOD1s with TCEP increased the accessibility to iodoacetamide of cysteine residues that normally participate in the formation of the intrasubunit disulfide bond (Cys-57 to Cys-146) or are buried within the core of the β-barrel (Cys-6). SOD1 enzymes in spinal cord lysates from G85R and G93A mutant but not wild type SOD1 transgenic mice also exhibited abnormal vulnerability to TCEP, which exposed normally inaccessible cysteine residues to modification by maleimide conjugated to polyethylene glycol. These results implicate SOD1 destabilization under cellular disulfide-reducing conditions at physiological pH and temperature as a shared property that may be relevant to amyotrophic lateral sclerosis mutant neurotoxicity.
Evaluation of internally consistent parameters for the triple-layer model by the systematic analysis of oxide surface titration data

Systematic analysis of surface titration data from the literature has been performed for ten oxides (anatase, hematite, goethite, rutile, amorphous silica, quartz, magnetite, δ-MnO2, corundum, and γ-alumina) in ten electrolytes (LiNo3, NaNO3, KNO3, CsNO3, LiCl, NaCl, KCl, CsCl, NaI, and NaClO4) over a wide range of ionic strengths (0.001 M–2.9 M) to establish adsorption equilibrium constants and capacitances consistent with the triple-layer model of surface complexation. Experimental data for the same mineral in different electrolytes and data for a given mineral/ electrolyte system from various investigators have been compared. In this analysis, the surface protonation constants (K,, and Ks,2) were calculated by combining predicted values of ΔpK(log Ks,2 − log Ks,1) (Sverjensky and Sahai, 1996) with experimental points of zero charge; site-densities were obtained from tritium-exchange experiments reported in the literature, and the outer-layer capacitance (C2) was set at 0.2 F·m−2. This scheme permitted us to retrieve consistent sets of values for the inner layer capacitance (C1), and for the electrolyte adsorption constants (Ks,L− and Ks,M+) corresponding, respectively, to the equilibria >SOH2+ + Laq− = >SOH2+ − L− and >SO− + Maq+ = >SO− − M+ Aqueous activity coefficients were calculated using the extended Debye-Huckel equation (Helgeson et al., 1981), which is valid to high ionic strengths (>0.5 M). Systematic analysis of the data reveals important trends and differences between triple-layer model predictions and experimental data and between data for the same mineral/ electrolyte from different investigators. Furthermore, the analysis yields an internally consistent set of triple-layer parameters which will be used in developing a predictive model for electrolyte adsorption based on Born solvation and electrostatic theory (Sahai and Sverjensky, 1997a).
Influences on foreign ownership level and entry mode choice in Vietnam

Abstract This study examines the determinants of (1) ownership level in equity joint ventures and (2) foreign market entry mode choice in the context of Vietnam. The first part is a replication of [Pan, Y. (1996). Influences on foreign equity ownership level in joint ventures in China. Journal of International Business Studies , 27, 1–26] study of foreign ownership level in equity joint ventures in China. Though Vietnam and China share some common characteristics, most of Pan's findings are not generalizable to Vietnam. The second part indicates that advertising intensity, country risk of Vietnam, project investment amount, project duration, cultural distance, competitive intensity, and location of investment have significant impacts on entry mode choice. An integrated analysis of joint venture ownership level and entry mode choice based on percentage of foreign equity suggests that only some of the above factors have statistically significant effects.
Alpha‐synuclein expression patterns in the colonic submucosal plexus of the aging Fischer 344 rat: implications for biopsies in aging and neurodegenerative disorders?

Background This experiment assessed normative expression patterns of alpha-synuclein (SYNC), including ganglionic remodeling and development of SYNC pathologies, in the submucosal plexus (SMP) of the colon during healthy aging. The observations address age-associated changes in bowel function and are relevant to evaluations of SMP-containing colonic biopsies for SYNC or synucleinopathies associated with aging and peripheral neurodegenerative diseases. Methods Colonic submucosal whole mounts from groups of virgin male Fischer 344 rats (n ≥ 8 per group) at 4, 8, 16, and 24 months of age were processed immunohistochemically for SYNC and the pan-neuronal marker HuC/D. In addition, macrophages immunoreactive for MHCII were examined. Stereological protocols were used to generate unbiased estimates of neuron density, neurons per ganglion, neurons per ganglionic area, and neuron size. Key Results The protein SYNC was expressed in a subpopulation of SMP neurons, in both nucleus and cytoplasm. The general age-associated pattern across different cell counts was an increase in the number of SYNC+ neurons between 4 and 8 months of age, with progressively decreasing numbers of both SYNC+ and SYNC- neurons over the remaining lifespan. The soma size of SYNC+ neurons increased progressively with age. Aggregated SYNC occurred in the aging SMP, and macrophages with alternatively activated profiles were located adjacent to pathological SYNC deposits, consistent with ongoing phagocytosis. Conclusions & Inferences Changes in SYNC expression with age, including a baseline of accumulating synucleinopathies in the healthy aging SMP, need to be considered when interpreting either functional disturbances or biopsies of the aging colon.
Theoretical problems in negotiating trade liberalization

Abstract This paper points out that the General Agreement on Tariffs and Trade (GATT)/World Trade Organization (WTO) trade liberalization possesses very special characteristics. I argue that these characteristics are responses to a set of problems inherent to contemporary trade liberalization. This is not a matter of mere historical interest. These problems remain very much with us, and recognition of this fact should influence our approach to future trade negotiations.
The social costs of development: A Puerto Rican case

Eduardo Seda. Social Change and Personality in a Puerto Rican Agrarian Reform Community. Evanston: Northwestern University Press, 1973. xxvi + 187 pp. Appendix, bibliography and index. $8.50.
Psychiatric Outcome of Temporal Lobectomy for Epilepsy: Incidence and Treatment of Psychiatric Complications

Summary: Purpose: To determine the incidence of psychiatric disorders before and after surgical treatment for partial epilepsy and to document the effectiveness of their treatment. Methods: Fifty consecutive patients treated surgically for focal epilepsy (44 temporal and six frontal) were evaluated by established neuropsychiatric methods before surgery and over a mean period of 2 years after surgery. The patients with interictal dysphoric disorders, with or without psychotic episodes, were treated with tricyclic antidepressant medication alone or combined with serotonin selective reuptake inhibitors and, if necessary, with the addition of risperidone. Results: Before surgery, 25 (57%) of the 44 patients with temporal lobe epilepsy had dysphoric disorders. After surgery, 17 (39%) of the 44 patients experienced either de novo psychiatric complications (six psychotic episodes, six dysphoric disorders, and two depressive episodes) or exacerbation of preoperative dysphoric disorder (three patients). Eight previously intact patients of the 19 (42%) developed dysphoric disorders after surgery that were significantly related to recurrence of seizures. All psychiatric complications occurred in the first 2 months after surgery, except for the six patients intact before surgery, who had a recurrence of seizures. A significant predictor of ultimate excellent psychiatric outcome was complete absence of seizures after surgery. All postoperative psychiatric complications remitted on treatment with psychotropic medication in the compliant patients. Conclusions: An exceptional psychiatric morbidity is associated with the months after temporal lobectomy. Possible pathogenetic mechanisms are discussed. Antidepressant drugs are very effective in treating the psychiatric disorders of chronic epilepsy; their use in conjunction with the surgical treatment of epilepsy appears to be crucial for the overall positive outcome of a significant number of patients.
Specific Factors, Capital Markets, Portfolio Diversification, and Free Trade: Domestic Determinants of the Repeal of the Corn Laws

Whereas the Ricardo-Viner specific factors model implies that owners of land and capital stood diametrically opposed to one another on the issue of free trade in nineteenth-century Britain, studies in the economic history literature posit that the economic interests of these two groups of factor owners were not mutually exclusive but rather overlapped as a result of rapid economic changes in the 1830s that intensified landowner diversification into nonagri-cultural ventures. Hence, the former views the repeal of the Corn Laws in 1846 as capital gaining the political upper hand over the landed elite, whereas the latter implies that landowners with diversified portfolios stood to gain from, or simply became indifferent to, free trade in grain. This paper alters the specific factors model to include the concepts of diversification and investment capital flows. It then tests the political implications of diversification, hypothesizing a positive correlation between constituency diversification and parliamentary voting on repeal of the Corn Laws. Both individual and aggregate sets of data confirm that diversified interests contributed to the free-trade policy outcome.
Intensity and transmission measurements in the ν3-fundamental of N2O at low temperatures

Spectral transmission of IR radiation through the nitrogen-broadened lines of the nu-3 fundamental of N2O has been measured at 154, 202 and 300 K. A value of 1411 + or - 54 per sq cm per atmosphere at STP has been obtained for the combined strength of the nu-3 and nu-2(1) + nu-3 - nu-2(1) bands, using the Wilson-Wells-Penner-Weber method. This value of the combined strength, the relative intensity calculations of Gray Young, the room-temperature data of Toth for nitrogen-broadened half-widths in the nu-1 + nu-3 and 2nu2(0) + nu-3 bands, and the variation of the line width with temperature proposed by Varanasi and Sarangi are shown to yield excellent agreement between the measured and computed spectral transmittance throughout the band.
On the correlation of exchange rates and interest rates

Abstract This note shows that a negative correlation between the price of foreign currency and nominal interest rates in not necessarily an indication of movements in the real rate of interests. Such a correlation could be consistent with a monetarist model in which the real rate is constant.
Plasma Synthesis of Highly Monodisperse Ge Nanocrystals and Self-Assembly of Dense Nanocrystal Layers

Germanium nanocrystals have been synthesized using a low-pressure, nonthermal plasma approach. The nanocrystal size can be adjusted between 4-20 nm by varying the plasma parame-ters, and the size distribution is relatively narrow with standard deviations of 10-20% of the av-erage crystal size. Stable colloidal solutions of the germanium crystals have been prepared by grafting organic alkene ligands onto the nanocrystal surfaces. When drop-cast from solution onto TEM grids, the nanocrystals form densely packed films.
Analysis of billiard ball computation using phase space logics

Abstract When analyzing individual gates in circuitry, one usually assumes that inputs are either 0 or 1, as are the outputs, but the fact is that these input values are really either “high” voltage or “low” voltage. Determining whether or not a given input is to be considered as high or low depends on a physical measurement of the voltage. Since physical measurement is never exact, it is more realistic to consider “high,” “low,” and “indeterminate,” hence considering three possible values, rather than two, when reasoning about computer hardware. When considering physical measurement as part of the determination as to what inputs and outputs are for a given gate, one can no longer reason about these gates using boolean logic. There are several possible non-boolean alternatives one may consider. We will examine motivation for some such alternatives and point out how we might apply them to a particular model of computation: the billiard ball model.
Twenty Years of Gene Targeting: What We Don't Know

It has been a little over 20 years since targeted gene disruption in the mouse was reported. This Perspectives article examines how we got to where we are and paints in broad strokes what we have and have not learned. Homologous recombination was well known in the latter half of the 20th century,1,2 but its use in the directed mutation, disruption, and alteration of the mammalian genome was hampered by the vanishingly small frequency with which it occurred.3 However, with powerful selection techniques, these infrequent events could be detected, and in 1987 to 1988 the Smithies and Capecchi laboratories published data documenting general strategies for targeted disruption in mouse embryo–derived stem cells.4–6 As targeted gene disruption of the mouse genome became established, transcription factors that impacted organ development were first, obvious targets, and because mouse embryo viability is dependent on a functional heart beginning at around day 10.5 to 11 of development, the essential role(s) these factors played in cardiac development began to become apparent.7 Scientific advances often come about because of a fortuitous mix of technology, people, and circumstance, and such was the case for a first, seminal study in which a gene known to be vital in controlling cardiac contractility was targeted for deletion. Thomas Doetschman, the first author on the paper from the Smithies' laboratory, was recruited to the University of Cincinnati, where Evangelia Kranias was working on the small protein, phospholamban. Kranias initiated a minisabbatical with Doetschman, taking on the project to “knockout” the phospholamban gene. The paper, which was published in Circulation Research in 1994,8 not only helped to define the role phospholamban played in normal cardiac function but also brought home to the cardiovascular community the powerful approach represented …
Evaluating spatial overlap and relatedness of white-tailed deer in a chronic wasting disease management zone.

Wildlife disease transmission, at a local scale, can occur from interactions between infected and susceptible conspecifics or from a contaminated environment. Thus, the degree of spatial overlap and rate of contact among deer is likely to impact both direct and indirect transmission of infectious diseases such chronic wasting disease (CWD) or bovine tuberculosis. We identified a strong relationship between degree of spatial overlap (volume of intersection) and genetic relatedness for female white-tailed deer in Wisconsin’s area of highest CWD prevalence. We used volume of intersection as a surrogate for contact rates between deer and concluded that related deer are more likely to have contact, which may drive disease transmission dynamics. In addition, we found that age of deer influences overlap, with fawns exhibiting the highest degree of overlap with other deer. Our results further support the finding that female social groups have higher contact among related deer which can result in transmission of infectious diseases. We suggest that control of large social groups comprised of closely related deer may be an effective strategy in slowing the transmission of infectious pathogens, and CWD in particular.
A Policy Model to Evaluate the Benefits, Risks and Costs of Warfarin Pharmacogenomic Testing

Background: In 2007, the US FDA added information about pharmacogenomics to the warfarin label based on the influence of the CYP2C9 and VKORC1 genes on anticoagulation-related outcomes. Payers will be facing increasing demand for coverage decisions regarding this technology, but the potential clinical and economic impacts of testing are not clear. Objective: To develop a policy model to evaluate the potential outcomes of warfarin pharmacogenomic testing based on the most recently available data. Methods: A decision-analytic Markov model was developed to assess the addition of genetic testing to anticoagulation clinic standard care for a hypothetical cohort of warfarin patients. The model was based on anticoagulation status (international normalized ratio), a common outcome measure in clinical trials that captures both the benefits and risks of warfarin therapy. Initial estimates of testing effects were derived from a recently completed randomized controlled trial (n = 200). Healthcare cost ($US, year 2007 values) and health-state utility data were obtained from the literature. The perspective was that of a US third-party payer. Probabilistic and one-way sensitivity analyses were performed to explore the range of plausible results. Results: The policy model included thromboembolic events (TEs) and bleeding events and was populated by data from the COUMAGEN trial. The rate of bleeding calculated for standard care approximated bleeding rates found in an independent cohort of warfarin patients. According to our model, pharmacogenomic testing provided an absolute reduction in the incidence of bleeds of 0.17%, but an absolute increase in the incidence of TEs of 0.03%. The improvement in QALYs was small, 0.003, with an increase in total cost of $US162 (year 2007 values). The incremental cost-effectiveness ratio (ICER) ranged from testing dominating to standard care dominating, and the ICER was <$US50 000 per QALY in 46% of simulations. Results were most sensitive to the cost of genotyping and the effect of genotyping. Conclusion: Our model, based on initial clinical studies to date, suggests that warfarin pharmacogenomic testing may provide a small clinical benefit with significant uncertainty in economic value. Given the uncertainty in the analysis, further updates will be important as additional clinical data become available.
RESPONSES TO MULTIPLE CHEMICAL CUES BY THE CRAYFISH ORCONECTES VIRILIS

To investigate how organisms respond to multiple cues, the responses of the crayfish Orconectes virilis to natural chemical stimuli presented both one at a time and in combinations were recorded in the laboratory. Following the introduction of predator (snapping turtle) odours, individuals decreased the rate of non-locomotory movements compared to control levels. The addition of food odour resulted in an increase in movement as well as postural changes. When both signals were presented simultaneously, the level of food-elicited movements was reduced and the extent of inhibition of food-related responses depended upon the relative intensity of the two types of input. The behavioural effect of predator odour introduction lasted about two hours. When alarm odour and food odour were presented simultaneously, movements were reduced even more strongly than with the predator odour-food odour combination. Presentation of two signals associated with danger (alarm and predator odours) resulted in a significantly greater reduction of food odour-induced movement than for either danger signal by itself.
Focus on melanoma

Much remains to be learned about the pathogenesis of melanoma. How do different receptors and signaling pathways regulate uncontrolled growth, invasion, and metastases? What is the role of solar exposure in the etiology of melanoma? As genetics and cell biology reveal pathways and key molecules, new targets for prevention and therapy will appear. Mouse models that recapitulate human melanoma and the relevant pathways should allow better preclinical models for screening and developing new classes of therapeutic agents.
On the robust rank analysis of linear models with nonsymmetric error distributions

Abstract The robust analysis of linear models based on R-estimates involves an estimate of a scale parameter which is used in the analysis as a standardizing constant. The consistency of previous estimates of this scale parameter required that the underlying errors be symmetrically distributed. This assumption is not always warranted, for instance in survival models. A new estimate is proposed for the scale parameter and it is shown to be consistent for nonsymmetric and symmetric error distributions. With this new scale estimate, a complete robust analysis of a linear model can be accomplished without assuming symmetry. The small sample properties of the analysis are examined in a Monte Carlo study of several different situations.
Time-dependent studies of single and multiple photoionization of H + 2

A time-dependent method is used to study the photoionization of the simplest one-electron molecule, ${\mathrm{H}}_{2}^{+}.$ We use the variational principle to solve the time-dependent Schr\"odinger equation for ${\mathrm{H}}_{2}^{+}$ in spherical coordinates $(r,\ensuremath{\theta})$ centered on the center of mass of the ${\mathrm{H}}_{2}^{+}$ system in a time-varying electromagnetic field, in the fixed-nuclei approximation. Bound and continuum states of ${\mathrm{H}}_{2}^{+}$ are obtained by diagonalizing the two-dimensional Hamiltonian for ${\mathrm{H}}_{2}^{+}$ on a uniform lattice. Two different algorithms for the time propagation of the Schr\"odinger equation are described, the first an explicit time propagator involving matrix multiplication and the second an implicit time propagator involving matrix inversion. Single-photoionization cross sections for ${\mathrm{H}}_{2}^{+}$ are presented for the cases where the laser field is oriented both parallel and perpendicular to the internuclear axis. Excellent agreement is found between the present calculations and previous work. Two- and three-photon ionization cross sections are also presented for the cases where the laser field is oriented both parallel and perpendicular to the internuclear axis. Comparison with previous work is available only for the parallel orientation case where good agreement is found with a previous time-independent calculation.
Stereotactic Radiosurgery for Epilepsy and Functional Disorders

Stereotactic radiosurgery is used for many indications. In functional neurosurgery, it is used to modulate the function of axons, neurons, and related brain circuits. In this article, indications, current techniques, and outcomes are discussed.
Timing of sound-evoked potentials and spike responses in the inferior colliculus of awake bats

Abstract Neurons in the inferior colliculus (IC), one of the major integrative centers of the auditory system, process acoustic information converging from almost all nuclei of the auditory brain stem. During this integration, excitatory and inhibitory inputs arrive to auditory neurons at different time delays. Result of this integration determines timing of IC neuron firing. In the mammalian IC, the range of the first spike latencies is very large (5–50 ms). At present, a contribution of excitatory and inhibitory inputs in controlling neurons' firing in the IC is still under debate. In the present study we assess the role of excitation and inhibition in determining first spike response latency in the IC. Postsynaptic responses were recorded to pure tones presented at neuron's characteristic frequency or to downward frequency modulated sweeps in awake bats. There are three main results emerging from the present study: (1) the most common response pattern in the IC is hyperpolarization followed by depolarization followed by hyperpolarization, (2) latencies of depolarizing or hyperpolarizing responses to tonal stimuli are short (3–7 ms) whereas the first spike latencies may vary to a great extent (4–26 ms) from one neuron to another, and (3) high threshold hyperpolarization preceded long latency spikes in IC neurons exhibiting paradoxical latency shift. Our data also show that the onset hyperpolarizing potentials in the IC have very small jitter (
Spectrophotometric Estimation of Metmyoglobin in Frozen Meat Extractsaa

SUMMARY Frozen meat-water extracts stored under lights exhibit a pattern of metmyoglobin formation similar to that in frozen steaks. The spectrophotometric method of analysis was satisfactory for estimating the percent metmyoglobin in the solutions. Fluorescent lights significantly increased the formation of metmyoglobin in the solutions, similar to that reported for frozen steaks. Dialyzing the extract inhibited the increase of metmyoglobin in the frozen solution when stored under light. Addition of copper, manganese, or calcium ions in the form of the chloride salts to the dialyzed solution did not increase rate of metmyoglobin formation appreciably. The addition of chloride salts of magnesium and iron contributed to an increase in the rate of metmyoglobin formation. When the dialysate was concentrated and added to the dialyzed residue there was a significant increase in the rate of metmyoglobin formation.
Distance learning: an option for your future?

Distance learning programs are proving to be very popular for advancing nursing education from both a continuing education and academic degree perspective. Whether one is exploring opportunities to maintain perianesthesia certification or to pursue an advanced academic degree, distance learning technologies offer many feasible options. The following article provides prospective distance learning students with a brief description of distance learning, including its history and evolution. Distance learning technologies are reviewed and key elements that can determine student satisfaction and success are discussed.
Predicting the progress of diffusively limited chemical reactions in the presence of chaotic advection.

The effects of chaotic advection and diffusion on fast chemical reactions in two-dimensional fluid flows are investigated using experimentally measured stretching fields and fluorescent monitoring of the local concentration. Flow symmetry, Reynolds number, and mean path length affect the spatial distribution and time dependence of the reaction product. A single parameter $\overline{\ensuremath{\lambda}}N$, where $\overline{\ensuremath{\lambda}}$ is the mean Lyapunov exponent and $N$ is the number of mixing cycles, can be used to predict the time-dependent total product for flows having different dynamical features.
Sensory biases underlie sex differences in tamarin long call structure

Within the vocal repertoires of many species, both males and females produce acoustic variants of the same call type. Despite the relative salience of the acoustic features that correlate with the caller's sex, little is known about the functional significance of this acoustic cue. Specifically, do conspecifics use this information when making behavioural decisions, implying that it is meaningful to signal receivers? And, if so, what selective pressures underlie the salience of the sex differences in call structure? Here we present a series of phonotaxis experiments designed to address these issues in the cottontop tamarin, Saguinus oedipus. We focus on the tamarin combination long call (CLC), a species-specific vocalization consisting of one to two chirps followed by three to four whistles, that functions in the context of social isolation and mate attraction. CLCs produced by males had significantly shorter whistles than those produced by females, although there was some overlap in the sex-specific ranges. Sex differences in the acoustic morphology of CLCs elicited consistent selective phonotaxis, suggesting that this acoustic cue is meaningful to signal receivers and that whistle duration is the primary acoustic feature used to determine the sex of the caller. Males preferred female CLCs consisting of the longest whistles, whereas females preferred male CLCs with the shortest whistles, suggesting that sensory biases in tamarins underlie sex differences in CLCs. These preferences persisted even when stimulus calls contained whistle durations that fell outside the natural range.
Vitamin B-6 requirements of humans

Abstract Vitamin B-6, also referred to as vitamin B 6 , is the generic descriptor for all 3-hydroxy-2-methylpyridine derivatives possessing the biological activity of pyridoxine. Convincing evidence of the essentiality of the vitamin was demonstrated when hyperirritability and epileptiform-type seizures were reported in infants fed autoclaved commercial liquid formula low in vitamin B-6; administration of the vitamin corrected these symptoms. Vitamin B-6 status and requirements have been assessed using several methodologies. Dietary assessment usually consists of 24-h recall and/or 2–7-d intake records with nutrient composition being estimated using values given in the US Department of Agriculture's Handbook 8 series. Frequently used biochemical assessment methodologies include xanthurenic acid excretion after a tryptophan load, urinary 4-pyridoxic acid level, urinary and plasma total vitamin B-6 levels, erythrocyte alanine and aspartate aminotransferase activity coefficients, and plasma pyridoxal-5′-phosphate concentration. The most accepted vitamin B-6 status parameter is plasma pyridoxal-5′-phosphate concentration; however, more than one method should be utilized in evaluating status. The minimum vitamin B-6 requirement of men as evaluated by different researchers using various methodologies seems to be about 0.65 to 1.25 mg/d; similar estimates have been made for women. Estimates of vitamin B-6 requirements of pregnant and lactating women range from about 2.1 to 7.6 mg/d; pregnancy may affect many of the parameters utilized for assessing vitamin B-6 status. Controlled feeding studies utilizing infants, children, and adolescents are mainly lacking. Recommended Dietary Allowances (RDAs) for vitamin B-6 have existed since 1968; these RDAs are based primarily on protein intake. A few other countries also have recommended intake values for the vitamin. Vitamin B-6 metabolism and requirements may be altered in several diseases and pathological conditions. The symptoms for some but not all patients with these diseases/conditions have been reported to improve when therapeutic doses of the vitamin are given. Vitamin B-6 has been shown to be toxic. Dosages above 200 mg pyridoxine hydrochloride/d are not recommended.
Vibrational Coherence Transfer and Trapping as Sources for Long-Lived Quantum Beats in Polarized Emission from Energy Transfer Complexes

We entertain vibrational coherence transfer and related processes as possible sources for certain long-lived quantum beats observed in time-resolved polarized emission signals from photosynthetic l...
Ca2+-induced conformational transition in the inhibitory and regulatory regions of cardiac troponin I.

Cardiac muscle activation is initiated by the binding of Ca(2+) to the single N-domain regulatory site of cardiac muscle troponin C (cTnC). Ca(2+) binding causes structural changes between cTnC and two critical regions of cardiac muscle troponin I (cTnI): the regulatory region (cTnI-R, residues 150-165) and the inhibitory region (cTnI-I, residues130-149). These changes are associated with a decreased cTnI affinity for actin and a heightened affinity for cTnC. Using Forster resonance energy transfer, we have measured three intra-cTnI distances in the deactivated (Mg(2+)-saturated) and Ca(2+)-activated (Ca(2+)-saturated) states in reconstituted binary (cTnC-cTnI) and ternary (cTnC-cTnI-cTnT) troponin complexes. Distance A (spanning cTnI-R) was unaltered by Ca(2+). Distances B (spanning both cTnI-R and cTnI-I) and C (from a residue flanking cTnI-I to a residue in the center of cTnI-R) exhibited Ca(2+)-induced increases of >8 A. These results compliment our previous determination of the distance between residues flanking cTnI-I alone. Together, the data suggest that Ca(2+) activation causes residues within cTnI-I to switch from a beta-turn/coil to an extended quasi-alpha-helical conformation as the actin-contacts are broken, whereas cTnI-R remains alpha-helical in both Mg(2+)- and Ca(2+)-saturated states. We have used the data to construct a structural model of the cTnI inhibitory and regulatory regions in the Mg(2+)- and Ca(2+)-saturated states.
Concentrated hydroxyapatite inks for direct-write assembly of 3-D periodic scaffolds

Hydroxyapatite (HA) scaffolds with a 3-D periodic architecture and multiscale porosity have been fabricated by direct-write assembly. Concentrated HA inks with tailored viscoelastic properties were developed to enable the construction of complex 3-D architectures comprised of self-supporting cylindrical rods in a layer-by-layer patterning sequence. By controlling their lattice constant and sintering conditions, 3-D periodic HA scaffolds were produced with a bimodal pore size distribution. Mercury intrusion porosimetry (MIP) was used to determine the characteristic pore size and volume associated with the interconnected pore channels between HA rods and the finer pores within the partially sintered HA rods.
QUANTUM YIELDS FOR ENZYME INACTIVATION AND THE AMINO ACID COMPOSITION OF PROTEINS

Summary A formula has been derived which as a first approximation, predicts the quantum yields for the inactivation of enzymes. The enzymes can be divided into a group containing cystine and the subtilisins which do not. The formula applied to subtilisin gives good agreement. For some of the enzymes, only cystine needs to be considered in the calculation; for others good agreement is found if contributions from aromatic groups are included. On this basis a quantum yield for tobacco mosaic virus protein is computed as 0.0047 at 2537 A. The origin of chemically modified histidine in photochemically inactivated lysozyme has yet to be explained.
Progress With Physically and Logically Reversible Superconducting Digital Circuits

We continue to develop a new Superconductor Flux Logic (SFL) family based on nSQUID gates with fundamentally low energy dissipation and the ability to operate in irreversible and reversible modes. Prospective computers utilizing the new gates can keep conventional logically irreversible architectures. In this case the energy dissipation is limited by fundamental thermodynamic laws and could be as low as a few kBT s per logic operation. Highly exotic and less practical logically and physically reversible circuit architectures are more attractive for us because they enable a reduction of the specific energy dissipation well below the thermodynamic threshold kBTln2. The reversible option is of interest to us because we can then experimentally demonstrate that all technical mechanisms of the energy dissipation could be cut below the fundamental thermodynamic limit. In other words, we like to set the energy dissipation record for all conventional digital technologies that (if measured in kBT ) is about one million times below the best figures achieved in commercially available semiconductor circuits. Besides, we believe that diving below the thermodynamic threshold would have impressive scientific and philosophical impacts. In the paper we introduce a new timing belt clocking scheme and present new circuits. While we still work with test circuits, some of them contain two 8-stage shift registers, one with direct and the other with inverted outputs. The energy dissipation per nSQUID gate per bit measured at 4 K temperature is already below the thermodynamic threshold. We are confident that we passed through the critical phase of the project and we simply need more time to make more sophisticated circuits. The extremely low energy dissipation converts our circuits into a natural candidate to support circuitry for any sensors operating at milli-Kelvin temperatures.