cssi/SciSciGPT-SciSciNet huggingface dataset:
Depression of hepatic glutathione by opioid analgesic drugs in mice

The ability of morphine and other opioid analgesic drugs to diminish hepatocellular glutathione (GSH) concentrations was examined in ICR mice. When administered intraperitoneally, morphine, hydromorphone, ethylmorphine, l-alpha-acetylmethadol (LAAM), and meperidine all caused a significant decrease in hepatic GSH concentrations in male mice while codeine, methadone, butorphanol, nalbuphine, and pentazocine were without effect even at doses up to those approaching acute lethality. Depression of hepatic GSH equivalent to that observed after ip administration could be elicited by icv administration of small doses of morphine, ethylmorphine, and hydromorphone. LAAM and meperidine were ineffective following icv administration in these experiments. The discrepancy between results following ip versus icv administration of LAAM and meperidine suggests that hepatic metabolism of some opioids may be important for their activity in the CNS, as both norLAAM and normeperidine diminished hepatic GSH when administered by the icv route. The opioid-induced lowering of hepatic GSH does not appear to be sex-dependent since morphine and LAAM produced qualitatively and quantitatively similar effects on hepatic GSH in female mice. Morphine administered icv produced a substantial increase in the hepatotoxicity of two compounds dependent upon GSH for detoxification, acetaminophen and cocaine, as measured by serum alanine aminotransferase activities. These observations indicate that a number of opioid analgesic drugs have the potential to diminish hepatic GSH. Further, these results support earlier studies which indicate that central opioid effects on hepatic GSH are mediated through mu-opioid receptor stimulation. Last, these studies suggest that a centrally initiated opioid action on hepatic GSH may significantly influence the susceptibility of the liver to the effects of some hepatotoxic agents.
Statistical correction of central Southwest Asia winter precipitation simulations

Severe drought is a notable feature of the hydrology of central Southwest (CSW) Asia. Although studies have linked the region's interannual precipitation variability to remote forcings that include East Asia jet stream variability and western Pacific tropical convection, atmospheric general circulation models (GCMs) forced by observed sea-surface temperatures demonstrate little skill in simulating interannual precipitation variability in this region. Here, statistical methods of correcting systematic errors in GCM simulations of CSW Asia precipitation are investigated. Canonical correlation analysis is used to identify model fields related to observed precipitation anomaly patterns. These relationships are then used to predict observed precipitation anomalies. This approach is applied to the ECHAM 4.5 GCM using regional precipitation, upper-level winds and western Pacific tropical precipitation as predictors of observed CSW Asia precipitation anomalies. The statistical corrections improve the GCM precipitation simulations, resulting in modest, but statistically significant, cross-validated skill in simulating CSW Asia precipitation anomalies. Applying the procedure to hindcasts with persisted sea-surface temperatures gives lower, but statistically significant, precipitation correlations in the region along the Hindu Kush mountain range. Copyright © 2003 Royal Meteorological Society
The Molecular Mechanism of Monolayer Scission

Hydrophobic globules surrounded by lipid monolayers are ubiquitous structures found in most cells, prokaryotic and eukaryotic. These structures, called lipid droplets, are hypothesized to accumulate as inclusions of oil-like molecules between the two leaflets of a membrane which grow larger and eventually bud off. The budding process is submicroscopic and difficult to observe in experiments, and studying it in molecular simulations has thus far presented computational challenges. Using dissipative particle dynamics, we attempt to understand the molecular details of the droplet budding process. We develop a lipid reservoir that can supply lipids to the bulging monolayer as the droplet buds out of the membrane. Our simulations support existing schematic models for the growth and budding process and predict a morphological transition between a partially and completely enveloped intermediate structure. Our results suggest a molecular mechanism for monolayer scission. Droplets generated using this technique can be useful in further studying the structure and dynamics of the droplet and its unique monolayer-integrated proteome.
Who asks and who receives in salary negotiation

The influence of individual differences and negotiation strategies on starting salary outcomes was investigated. A sample of 149 newly hired employees in various industry settings participated in this study. Results indicated that those who chose to negotiate increased their starting salaries by an average of $5000. Individuals who negotiated by using competing and collaborating strategies, characterized by an open discussion of one's positions, issues, and perspectives, further increased their salaries as compared to those who used compromising and accommodating strategies. Individual differences, including risk-aversion and integrative attitudes, played a significant role in predicting whether or not individuals negotiated, and if so, what strategies they used. Copyright © 2009 John Wiley & Sons, Ltd.
Erythrocyte Deformation in Human Muscular Dystrophy

Erythrocytes from patients with congenital muscular dystrophy exhibit dramatic surface deformation when observed with a scanning electron microscope. A similar alteration, but one affecting a smaller proportion of cells, occurs in the case of female carriers of the sex-linked Duchenne dystrophic condition. These observed changes in the erythrocyte surface may reflect a systemic defect in membrane properties.
Saffman-Taylor problem in sector geometry: Solution and selection

We develop an analytical method to extend the two-parameter family of analytical solutions in channel geometry to sector geometry with arbitrary opening angle at zero surface tension. We then show how to apply the WKB method to select the limiting finger width at very small surface tension. The result agrees very well with experiment. We also discuss stability of the pattern based on the special structure of these selected solutions.
Small Satellites: The Desire for a Mass Producible, Mass Customizable Nanosatellite

Small satellites played a key role at the dawn of the Space Age. It could very well be the case that their progeny will pave the way for satellites of Generation-after-Next where they are produced as mass produced commodities. The Aerospace Corporation, a California nonprofit corporation operates a Federally Funded Research & Development Center sponsored by the Air Force, is conducting research and technology development to radically change the way satellites are designed, manufactured and assembled. One critical area of investigation is whether the structural material of a satellite needs to be made of metal or carbon/polymer composite, as it is currently done, or whether glass ceramics could be used where it becomes possible to integrate electronic, RF, optical and fluidic functions on the same structural substrate. Since their invention nearly 60 years ago, glass ceramic materials have been used in a wide range of applications from human health (e.g., medical and dental) to consumer commodities (e.g., electronics) to transportation (e.g., aerospace). The material class has technological appeal since it is manufactured in the glassy amorphous phase and can be shaped via low cost “plastic” molding techniques, and then converted via a heat treatment step to the ceramic form. The photostructurable glass ceramics (PSGCs) are a subclass of the glass-ceramics. These materials include photo-sensitizer compounds that initiate the ceramization process. The advantage of the PSGC materials is that they can be lithographically patterned and the exposed areas can be subsequently converted into at least two ceramic phases, one of which is soluble in dilute hydrofluoric (HF) acid. Consequently, the fabrication of intricate microstructures by lithographic or laser direct-write techniques is now a commercial success. Because the material transformation process is photolytically initiated, other material properties can also be “activated” on a local scale through patterning. In a series of investigations, we have developed specialized laser direct write irradiation tooling that explores the effect of metered exposure to alter specific material properties. For the commercially available PSGC Foturan™ we can alter the chemical solubility, mechanical strength, optical transmission, RF and acoustic properties. Other published work has demonstrated changes in the optical index. We have applied this knowledge in the development of an integrated cold gas propulsion system for a 1kg class nanosatellite vehicle that is largely made of PSGC materials. The micropropulsion system includes valves, electronics, wireless telemetry and a control system to demonstrate “leader-follower” or station keeping maneuvers on an air table. PSGC like materials can be used as a structural small-satellite material and this simple change of material choice could usher in the use of digital-direct-development methodologies and the manufacturing of nanosatellites in mass production quantities. All trademarks, service marks, and trade names are the property of their respective owners.
Excited-state molecular photoionization dynamics

This review presents a survey of work using resonance-enhanced multiphoton ionization and double-resonance techniques to study excited-state photoionization dynamics in molecules. These techniques routinely provide detail and precision that are difficult to achieve in single-photon ionization from the ground state. The review not only emphasizes new aspects of photoionization revealed in the excited-state experiments but also shows how the excited-state techniques can provide textbook illustrations of some fundamental mechanisms in molecular photoionization dynamics. Most of the examples are confined to diatomic molecules.
Expression, crystallization and preliminary X-ray studies of the PDZ domain of Dishevelled protein.

Dishevelled (Dsh) protein is an important component of the Wnt signal-transduction pathway. It has three relatively conserved domains: DIX, PDZ and DEP. The PDZ domain of the Xenopus laevis homolog of Dsh, which consists of residues 254–348, was overexpressed as a soluble protein in Escherichia coli, purified and crystallized. The crystals were obtained by the vapor-diffusion method, using 1.4 M sodium formate as a precipitant. The crystals diffracted to 2.3 A resolution. The space group was determined to be P6122 or P6522, with unit-cell dimensions a = b = 95.9, c = 93.9 A.
Heating of the solar middle chromosphere by large-scale electric currents

A global resistive, two-dimensional, time-dependent magnetohydrodynamic (MHD) model is used to introduce and support the hypothesis that the quiet solar middle chromosphere is heated by resistive dissipation of large-scale electric currents which fill most of its volume. The scale height and maximum magnitude of the current density are 400 km and 31.3 m/sq m, respectively. The associated magnetic field is almost horizontal, has the same scale height as the current density, and has a maximum magnitude of 153 G. The current is carried by electrons flowing across magnetic field lines at 1 m/s. The resistivity is the electron contribution to the Pedersen resitivity for a weakly ionized, strongly magnetized, hydrogen gas. The model does not include a driving mechanism. Most of the physical quantities in the model decrease exponentially with time on a resistive timescale of 41.3 minutes. However, the initial values and spatial; dependence of these quantities are expected to be essentially the same as they would be if the correct driving mechanism were included in a more general model. The heating rate per unit mass is found to be 4.5 x 10(exp 9) ergs/g/s, independent of height and latitude. The electron density scale height is found to be 800 km. The model predicts that 90% of the thermal energy required to heat the middle chromosphere is deposited in the height range 300-760 km above the temperature minimum. It is shown to be consistent to assume that the radiation rate per unit volume is proportional to the magnetic energy density, and then it follows that the heating rate per unit volume is also proportional to the energy from the photosphere into the overlying chromosphere are briefly discussed as possible driving mechanisms for establishing and maintaining the current system. The case in which part of or all of the current is carried by protons and metal ions, and the contribution of electron-proton scattering to the current are also considered, with the conclusion that these effects do not change the qualitative prediction of the model, but probably change the quantitative predictions slightly, mainly by increasing the maximum magntiude of the current density and magnetic field to at most approximately 100 mA/m and approximately 484 G, respectively. The heating rate per unit mass, current density scale height, magnetic field scale height, temperatures, and pressures are unchanged or are only slightly changed by including these additional effects due to protons and ions.
Discrepancies in diagnoses of neuroepithelial neoplasms: the San Francisco Bay Area Adult Glioma Study.

BACKGROUND Valid and reliable diagnoses of disease are key both to meaningful epidemiologic and clinical investigations and to decision-making about appropriate treatment. One previous study highlighted the lack of precision in diagnosing primary brain tumors in a neuropathology referral practice. The current study explores diagnostic discrepancies in a population-based adult glioma series by hospital of origin, specialty training of the original diagnosing pathologist, and clinical significance. METHODS To confirm patients' eligibility for the San Francisco Adult Glioma Study, the authors obtained participants' pathology specimens and conducted a uniform secondary neuropathology review. Eligible patients were all adults age 20 years or older newly diagnosed with glioma between August 1, 1991, and March 31, 1994, who resided in 1 of 6 San Francisco Bay Area counties. RESULTS Overall, the original and secondary diagnoses were the same (concordant) for 352 (77%) of the 457 cases available for study. Twenty-six percent of the cases from community hospitals were discordant, compared with 12% of the cases from academic hospitals P = 0.004. Of the 105 discordant diagnoses, 17 (16%) were determined to be clinically significant, defined as a difference that could significantly alter patient management and/or prognosis. Sixteen of these 17 cases originated at community hospitals, and only 1 originated at a hospital with a neuropathologist. Based on the distribution of review diagnoses, subjects presenting at nonacademic hospitals were more likely than those presenting at academic hospitals to have glioblastoma (61% vs. 52%; P = 0.07). CONCLUSIONS The percentage of cases with discrepant original and review diagnoses was higher among those originally diagnosed at community hospitals without a neuropathologist than among those originally diagnosed at an academic hospital with a neuropathologist. Clinically significant discrepancies were much more likely to have originated at a community hospital without a neuropathologist. These data highlight the importance of review of brain tumors by a neuropathologist prior to decision-making regarding treatment. A separate implication of this study is that glioma cases selected exclusively from academic or nonacademic institutions in a particular geographic area are unlikely to be representative of all cases occurring in that area. Cancer 2000;88:2342–9. © 2000 American Cancer Society.
Optimum Elastic Design of A Reinforced Beam

Optimum fiber distributions in composite elastic beams are investigated us ing the criteria of minimum strain energy and maximum failure load. Ar bitrarily specified bounds are placed upon the specific volume fraction of fibers, and the total volume of fibers available for reinforcing the beam is assumed to be fixed. Numerical results are presented for beams constructed of ordinary and bimodulus composite materials. For the examples considered it is found that significant improvements in both stiffness and strength generally can be achieved through the use of nonuniform fiber distributions.
Evidence that BDNF regulates heart rate by a mechanism involving increased brainstem parasympathetic neuron excitability

Autonomic control of heart rate is mediated by cardioinhibitory parasympathetic cholinergic neurons located in the brainstem and stimulatory sympathetic noradrenergic neurons. During embryonic development the survival and cholinergic phenotype of brainstem autonomic neurons is promoted by brain-derived neurotrophic factor (BDNF). We now provide evidence that BDNF regulates heart rate by a mechanism involving increased brainstem cardioinhibitory parasympathetic activity. Mice with a BDNF haploinsufficiency exhibit elevated resting heart rate, and infusion of BDNF intracerebroventricularly reduces heart rate in both wild-type and BDNF+/- mice. The atropine-induced elevation of heart rate is diminished in BDNF+/- mice and is restored by BDNF infusion, whereas the atenolol-induced decrease in heart rate is unaffected by BDNF levels, suggesting that BDNF signaling enhances parasympathetic tone which is diminished with BDNF haploinsufficiency. Whole-cell recordings from pre-motor cholinergic cardioinhibitory vagal neurons in the nucleus ambiguus indicate that BDNF haploinsufficiency reduces cardioinhibitory vagal neuron activity by increased inhibitory GABAergic and diminished excitatory glutamatergic neurotransmission to these neurons. Our findings reveal a previously unknown role for BDNF in the control of heart rate by a mechanism involving increased activation of brainstem cholinergic parasympathetic neurons.
Cytochemistry of type II pneumocytes in Chediak-Higashi syndrome of mice.

Abstract The type II pneumocytes of beige mice with the Chediak-Higashi syndrome (CHS) have been compared ultrastructurally and histochemically with those of normal black mice in both newborn and adult animals. In normal black mice the inner face of the limiting membrane of lamellar bodies near the cell surface revealed continuous dialyzed iron (DI) staining as did the luminal surface of the cell. The periodate-thiocarbohydrazide-silver proteinate (PA-TCH-SP) method stained selectively the luminal surface of the granular pneumocyte together with multivesicular bodies and the inner face of the limiting membrane of lamellar bodies, in normal black mice thus supporting the role of multivesicular bodies as precursors of lamellar bodies. The beige mice lacked the layer of continuous DI staining lining the superficial lamellar bodies. Moreover, the PA-TCH-SP staining was negligible on the limiting membrane of large lamellar bodies in beige mice. Immunostaining for lysozyme appeared weaker in the large lamellar bodies of type II pneumocytes of the beige mice. Peroxisomes were normal in size but somewhat increased in number in type II pneumocytes of beige mice. The multivesicular bodies as well as the lamellar bodies increased in size and decreased in number in the beige mice and, in some cell profiles, multivesicular bodies or lamellar bodies appeared to be fusing. Since the multivesicular bodies are thought to be precursors of lamellar bodies, these findings indicate that atypical fusion of the lysosomes in type II pneumocytes occurs at early to late stages of maturation. Newborn beige mice disclosed a greater and more consistent increase in size of the lamellar bodies than did adult beige mice. Compared with newborn black mice the newborn beige mice revealed fewer secreted lamellar bodies in the alveolar space. The cytochemical and morphological changes in lamellar bodies and their precusor multivesicular bodies in type II pneumocytes of beige mice are interpreted as resulting from increased fusion of the precursor bodies and lamellar bodies with one another. Impaired secretion of lamellar bodies possibly also contributes to increased size of lamellar bodies and content of lamellar body material in granular pneumocytes of beige mice.
The entitlements of unallied hunters after a sequential capture

As the famous fox case of Pierson v Post illustrates, rival hunters who have separately contributed to the capture of a wild animal may have different notions about which of them owns the prey. During the Stone Age, hunter-gatherers likely developed sophisticated norms to resolve these sorts of controversies. Each of the contributors to this symposium focuses on common law property rights in prey that North American judges articulated during the nineteenth century. Their articles analyse the rules of the game that applied in the Newfoundland sealery, North Pacific whaling grounds, and rural Long Island. In each setting, both hunters and judges tailored the applicable rules of capture to the characteristics of the hunted animal. When hunters’ customs were opaque, as they commonly were, judges sought to crystallize definitive legal rules. The articles in the symposium strikingly illustrate the gulf between ‘humanistic’ and ‘scientific’ styles of legal analysis.
Importance of temporal relationships in combined modality radioimmunotherapy of breast carcinoma.

BACKGROUND. The beneficial effects of radioimmunotherapy (RIT) may result from activation of molecular pathways that lead to programmed cell death (apoptosis). The influences of sequence and timing of 99 Y-DOTA-peptide-ChL6 antibody ( 90 Y-ChL6) and anti-epidermal growth factor receptor antibody (ch225) or paclitaxel (Taxol; Bristol-Myers Squibb, Princeton, NJ) on efficacy and toxicity were examined. METHODS. Groups of human breast carcinoma (HBT 3477) tumored mice received paclitaxel (300 or 600 μg) or ch225 (70, 150, or 350 μg) at various intervals before or after 90 Y-ChL6. Mortality, hematologic toxicity, weight loss, and therapeutic efficacy were evaluated. RESULTS. Mice receiving paclitaxel within 24 hours of 90 Y-ChL6 had a 100% response rate; 48% were cured when paclitaxel was given 6 or 24 hours after 90 Y-ChL6. When 150 μg ch225 was given 24 hours before 90 Y-ChL6, the response and cure rates surpassed those of 90 Y-ChL6 alone. Timing of administration was critical, with mortality rates as high as 80% in some groups receiving 350 μg ch225 and 90 Y-ChL6. CONCLUSIONS. In this aggressive human breast carcinoma model, combined 90 Y-ChL6 and paclitaxel had a high therapeutic index with many cures. Sequence of administration was critical in order for ch225 or paclitaxel, when combined with 90 Y-ChL6, to enhance the response rate.
Functional interaction between cyclin T1/cdk9 and Purα determines the level of TNFα promoter activation by Tat in glial cells

In addition to its stimulatory effect on transcription of the HIV-1 LTR, the early protein of HIV-1, Tat, exhibits detrimental effects on the CNS by deregulating the expression of several cytokines and immunomodulators including TNFalpha. Activation of the viral promoter by Tat requires several cellular proteins including cyclin T1 and its partner, cdk9, which upon association with the TAR sequence of the LTR, forms a complex that enhances the activity of RNA polymerase II. Here, we examined the involvement of cyclin T1/cdk9 in Tat-mediated transcriptional activation of the TNFalpha promoter which has no TAR sequence. Results from transfection of human astrocytic cells revealed that both cyclin T1 and cdk9 stimulate the basal promoter activity of TNFalpha, although the level of such activation is decreased in the presence of Tat. Ectopic expression of Puralpha, a brain-derived regulatory protein which binds to Tat, enhanced the basal level of TNFalpha transcription, yet exerted a negative effect on the level of Tat activation of the TNFalpha promoter. The antagonistic effect of Puralpha and Tat upon the TNFalpha promoter was diminished in the presence of cyclin T1 and cdk9, suggesting cooperativity of Puralpha with cyclin T1 and cdk9 in Tat activation of the TNFalpha promoter. Results from protein-protein binding studies showed the interaction of Puralpha with both cyclin T1 and cdk9 through distinct domains of Puralpha which are in juxtaposition with each other. Interestingly, the site for cyclin T1 binding within Puralpha is adjacent to the region which is important for Tat/Puralpha association. In light of these observations, we propose a model which ascribes a bridging role for Puralpha in assembling Tat, cyclin T1, and cdk9 around the promoter region of TAR-negative genes such as TNFalpha, which is responsive to Tat activation.
Quality of service guarantees in virtual circuit switched networks

We review some recent results regarding the problem of providing deterministic quality of service guarantees in slot-based virtual circuit switched networks. The concept of a service curve is used to partially characterize the service that virtual circuit connections receive. We find that service curves provide a convenient framework for managing the allocation of performance guarantees. In particular, bounds on end-to-end performance measures can be simply obtained in terms of service curves and burstiness constraints on arriving traffic. Service curves can be allocated to the connections, and we consider scheduling algorithms that can support the allocated service curves. Such an approach provides the required degree of isolation between the connections in order to support performance guarantees, without precluding statistical multiplexing. Finally, we examine the problem of enforcing burstiness constraints in slot-based networks. >
Optimal diet of horses with chronic exertional myopathies.

Chronic exertional rhabdomyolysis represents a syndrome of recurrent exercise-associated muscle damage in horses that arises from a variety of etiologies. Major advances have been made in the understanding of the pathophysiology of this disease, and causative genetic defects have been recently identified for two conditions—polysaccharide storage myopathy of quarter horses, paints, warm bloods, and draft breeds. Dietary management in combination with a regular exercise regimen comprises the most effective means for control of clinical signs.
Reproductive biology of the male leaf‐nosed bat, Macrotus waterhousii in Southwestern United States

The reproductive biology of the bat Macrotus waterhousii was investigated anatomically and physiologically several times monthly throughout the year. The male spermatogenic cycle is initiated in June; sperm are available in August. Testicular hypertrophy is accompanied by increased levels of testicular ascorbic acid and circulating plasma testosterone. Sperm are present in the seminiferous tubules and later the epididymides from August to early December. Regression in testicular size begins in late September and testes are involuted by early December. Levels of testicular ascorbic acid and plasma testosterone decline at this time, although detectable amounts of both are present year-round. Mature sperm are absent from the male tract after late November or early December. The accessory sex gland complex and Cowper's glands undergo an annual cycle in synchrony with the testicular cycle. The accessory complex contains fructose, the concentration of which varies seasonally in direct proportion to glandular hypertrophy. Only trace levels of fructose are elaborated by Cowper's glands undergo an annual cycle in synchrony with the testicular cycle. The accessory complex contains fructose, the concentration of which varies seasonally in direct proportion to glandular hypertrophy. Only trace levels of fructose are elaborated by Cowper's glands. In contrast to vespertilionid bats, where the accessory glands remain enlarged and active when testes involute, those in Macrotus regress. The penis differs structurally from that of other temperate North American bats, primarily by lacking a bony baculum and specialized erectile accessory corpus cavernosus bodies. Males are not reproductively active in their first autumn.
An Analysis of Possible U.S. Sugar Import Policy Revisions

The U.S. sugar import policy, while supporting domestic producers, has had indirect effects on other markets. This study extends previous analyses to look at effects of sugar policy changes from a total agricultural sector perspective. The effects of sugar policy reform are studied with and without changes in farm program provisions for other crops. The results show welfare losses due to the sugar program. It is also shown that reduction of farm programs without altering the sugar quota tilts the terms of trade toward sugar producers giving them a competitive advantage and it is implied that both sets of policies need to be revised simultaneously to avoid distortions between commodities.
Chronic Cavitary Histoplasmosis: Failure of Oral Treatment with Ketoconazole

Ketoconazole appears to be a safe drug in the treatment of chronic cavitary histoplasmosis. Primary failure and relapse have been described, requiring amphotericin B, even after long therapy with ketoconazole. Four typical cases are presented. We caution about such potential failures and stress the importance of close observation of patients begun on therapy with ketoconazole for chronic cavitary histoplasmosis.
Statistical analysis of three fourth-order ordinary differential equation solvers

We develop an autoregressive integrated moving average (ARIMA) model to study the statistical behavior of the numerical error generated from three fourth-order ordinary differential equation solvers: Milne's method, Adams–Bashforth method and a new method that randomly switches between the Milne and Adams–Bashforth methods. With the actual error data based on three differential equations, we desire to identify an ARIMA model for each data series. Results show that some of the data series can be described by ARIMA models but others cannot. Based on the mathematical form of the numerical error, other statistical models should be investigated in the future. Finally, we assess the multivariate normality of the sample mean error generated by the switching method.
Noise subspace techniques in non-gaussian noise using cumulants

We consider noise subspace methods for narrowband direction-of-arrival or harmonic retrieval in colored linear non-gaussian noise of unknown covariance and unknown distribution. The non-gaussian noise covariance is estimated via higher order cumulants and combined with correlation information to solve a generalized eigenvalue problem. The estimated eigenvectors are used in a variety of noise subspace methods such as multiple signal classification (MUSIC), MVDR and eigenvector. The noise covariance estimates are obtained in the presence of the harmonic signals, obviating the need for noise-only training records. The covariance estimates may be obtained nonparametrically via cumulant projections, or parametrically using autoregressive moving average (ARMA) models. An information theoretic criterion using higher order cumulants is presented which may be used to simultaneously estimate the ARMA model order and parameters. Third- and fourth-order cumulants are employed for asymmetric and symmetric probability density function (pdf) cases, respectively. Simulation results show considerable improvement over conventional methods with no prewhitening. The effects of prewhitening are particularly evident in the dominant eigenvalues, as revealed by singular value decomposition (SVD) analysis. >
‘Zip codes’ direct intracellular protein tyrosine phosphatases to the correct cellular ‘address’

The transmembrane and intracellular protein tyrosine phosphatases (PTPs) play an essential role as signal transduction proteins involved in various cellular processes including division, proliferation and differentiation. As such, their activity must be strictly regulated to avoid nonspecific tyrosine dephosphorylation of cellular proteins. The intracellular PTPs possess a diversity of protein sequences outside the catalytic domain that appear to serve as 'zip codes' specifically 'addressing' these proteins to defined subcellular compartments. These localization strategies are proposed to function as a regulatory mechanism, defining the substrate specificity and function of the intracellular PTPs.
Development of long-lived high-performance zinc-calcium/nickel oxide cells

The addition of Ca(OH)2 to the zinc electrode of Zn/KOH/NiOOH cells was investigated in order to determine its effect on the rate of zinc active material redistribution (shape change) and cell cycle-life performance. Cells of equal mass and capacity, and therefore the same specific energy, containing 0, 10, 25, and 40 mol% Ca(OH)2 in their zinc electrodes were constructed and tested. The Ca(OH)2 and Zn(OH) 4 2− -supersaturated KOH solution formed a calcium-zincate complex during the discharge half-cycle. The solubility of this complex is less than that of ZnO, and the lower zinc species solubility leads to a slower rate of Zn redistribution, thereby extending the cell cycle life. The best cells tested were those with 25%-Ca(OH)2 electrodes, which lost capacity at a rate of 0.13%/cycle, compared to 0.47%/cycle in calcium-free control cells constructed in the same manner. Also, zinc active material utilization in the calcium-containing electrodes showed a dramatic improvement, compared to the calcium-free zinc electrodes.
Molecular Exciton Cluster States and Spectra with Application to Benzene

A cluster expansion is introduced for the determination of the optical absorption properties of cluster states in substitutionally disordered molecular crystals. This method is based on the Green's function expansion in terms of the localized cluster states in the energy region of the guest sub-band. The general features of the method are illustrated by calculations for a simple two-dimensional molecular crystal. The physical parameters for the calculation are based on the v11 benzene vibrational exciton. Both polarized and unpolarized cluster optical absorptions display strong asymmetries, with respect to the isolated guest spectral line. Calculations are performed on the monomer, dimer, trimer, and tetramers (three kinds) of the benzene crystal ac-plane. Es wird eine Clusterentwicklung fur die Bestimmung der optischen Absorptionseigenschaften der Clusterzustande in substitntionsfehlgeordneten Molekularkristallen eingefuhrt. Diese Methode beruht auf der Entwicklung der Greenschen Funktion nach den lokalisierten Clusterzustanden im Energiebereich der Gast-Subbanden. Das allgemeine Vorgehen dieser Methode wird durch Rechnungen fur einen simplen zweidimensionalen Molekulkristall illustriert. Die physikalischen Parameter fur die Rechnungen basieren auf dem Benzen-v11-Schwingungsexziton. Sowohl die polarisierte als auch die unpolarisierte optische Clusterabsorption zeigt starke Asymmetrie bezuglich der isolierten Gast-Spektrallinie. Rechnungen werden fur die Monomere, Dimere, Trimere und Tetramere (drei Arten) der Benzenkristall-ac-Ebene durchgefuhrt.
Between Archive and Participation: Public Memory in a Digital Age

In sizing up the notion of public memory, rhetoricians would be remiss not to consider the increasing influence of new media on today's remembrance culture. This article addresses memorial functions of the internet in light of recent scholarly debates about virtues and drawbacks of modern “archival memory” as well as the paradoxical link between the contemporary public obsession with memory and the acceleration of amnesia. To explore the strengths and limitations of the internet as a vehicle of collecting, preserving, and displaying traces of the past, the article examines The September 11 Digital Archive, a comprehensive online effort to document public involvement in recording and commemorating the tragedy of 11 September, 2001.
Responses of neurons to click-pairs as simulated echoes: Auditory nerve to auditory cortex

When two identical sounds are presented from different locations with a short interval between them, the perception is of a single sound source at the location of the leading sound. This “precedence effect” is an important behavioral phenomenon whose neural basis is being increasingly studied. For this report, neural responses were recorded to paired clicks with varying interstimulus intervals, from several structures of the ascending auditory system in unanesthetized animals. The structures tested were the auditory nerve, anteroventral cochlear nucleus, superior olivary complex, inferior colliculus, and primary auditory cortex. The main finding is a progressive increase in the duration of the suppressive effect of the leading sound (the conditioner) on the response to the lagging sound (the probe). The first major increase occurred between the lower brainstem and inferior colliculus, and the second between the inferior colliculus and auditory cortex. In neurons from the auditory nerve, cochlear nucleus, ...
RACE AND COLLEGE ADMISSIONS: AN ALTERNATIVE TO AFFIRMATIVE ACTION?

During the late 1990s, several states eliminated affirmative action admissions policies at their public colleges. Some of these states substituted a program that grants admission to the top x% of each high school's graduating class. These new programs were instituted in efforts to restore minority college enrollments to their prior levels. This paper finds that the preferences given to minority applicants under affirmative action are large and that the minority share of admitted students in top-tier institutions would fall substantially after eliminating these preferences. However, there are not sufficient numbers of minorities in the top x% of their high school for the expected recovery from an x% program to be very large. Furthermore, most minority beneficiaries would have been accepted without these programs. As a result, x% programs are unable to replace traditional affirmative action and maintain the share of minority students.
How people recall, recognize, and reuse search results

When a person issues a query, that person has expectations about the search results that will be returned. These expectations can be based on the current information need, but are also influenced by how the searcher believes the search engine works, where relevant results are expected to be ranked, and any previous searches the individual has run on the topic. This paper looks in depth at how the expectations people develop about search result lists during an initial query affect their perceptions of and interactions with future repeat search result lists. Three studies are presented that give insight into how people recall, recognize, and reuse results. The first study (a study of recall) explores what people recall about previously viewed search result lists. The second study (a study of recognition) builds on the first to reveal that people often recognize a result list as one they have seen before even when it is quite different. As long as those aspects that the searcher remembers about the initial list remain the same, other aspects can change significantly. This is advantageous because, as the third study (a study of reuse) shows, when a result list appears to have changed, people have trouble re-using the previously viewed content in the list. They are less likely to find what they are looking for, less happy with the result quality, more likely to find the task hard, and more likely to take a long time searching. Although apparent consistency is important for reuse, people's inability to recognize change makes consistency without stagnation possible. New relevant results can be presented where old results have been forgotten, making both old and new content easy to find.
The pionic contribution to diffuse γ-rays: upper limits

Abstract Diffuse γ-rays probe the highest-energy processes at the largest scales. Here we derive model-independent constraints on the hadronic contribution to the Galactic and extragalactic γ-ray spectra at in the energy range 50 MeV ≲E γ ≲10 GeV . The hadronic component is dominated by emission from neutral pions, with a characteristic spectrum symmetric about mπ0/2. We exploit the well-defined properties of the pion decay spectrum to quantify the maximum pionic fraction of the observed γ-ray intensity. We find that the Galactic spectrum above 30 MeV can be atmost about 50% pionic. The maximum pionic contribution to the extragalactic spectrum is energy dependent; it also depends on the redshift range over which the sources are distributed, ranging from as low as about 20% for pions generated very recently, to as much as 90% if the pions are generated around redshift 10. The implications of these constraints for models of γ-ray and neutrino emission are briefly discussed.
Characteristics of a high-current, high-voltage Shockley diode

This paper describes design, development, characterization, and operation of a two-terminal, high-current, high-voltage silicon four-layer diode. The main feature of this new four-layer diode is a voltage-current characteristic which is, prior to switching, similar to that of an avalanche diode. This property is achieved by short-circuiting one emitter-base junction, resulting in a grid-type emitter geometry. The short-circuiting takes place over the entire device area in order to maintain uniform turn-on and uniform current conduction. Devices switching at 1000 volts or higher, with peak pulse current capability of 1000 amperes or more, are described. To achieve very high switching voltages, the stacking of two or three silicon chips was found to be useful. Extended tests Were performed at various combinations of pulsewidths (0.5 to 12 µs), repetition rates (0.2 to 2000 pulses per second), and operating times (0.1 to 2500 hours). The test circuits and the resulting turn-on and recovery times are summarized, Failure analysis establishes hot spot development or thermal fatigue as possible failure mechanisms. Since series operation of many devices is possible without complicated dividing networks, the complexity of pulse modulator circuitry is reduced, and resonantly charged circuits can exhibit a high degree of operation reliability and temperature insensitivity.
Waves in low‐β plasmas: Slow shocks

Results from wave theory and numerical simulation of the nonlinear MHD equations are used to study the response of a conducting fluid containing an embedded magnetic field with beta less than 1 to the sudden injection of material along the field lines. It is shown that the injection produces slow shocks with configurations which are concave toward the ejecta driver. Fast-mode waves which have not steepened into the shock precede the slow shock and alter the ambient medium. When beta equals 0.1, the fast mode becomes a transverse wave for parallel propagation, while the slow wave approaches a longitudinal, or sound, wave.
Cell-Based GATA4 Cardiac Gene Transfer Using Cell-Penetrating Peptide

See related article, pages 1626–1633 Congestive heart failure (CHF) is the only cardiovascular disease that is increasing in prevalence.1 Patients with CHF who have symptoms with mild activity or at rest (Class III and Class IV) have a poor long-term outcome, with 5-year age-adjusted mortality of 50%.2,3 Heart transplantation has an 80% 5-year survival rate, but only 3000 cardiac transplants are performed in the US each year, where the prevalence for severe CHF is estimated at 5 million patients.4 Angiotensin converting enzyme inhibitors, aldosterone antagonists, β-adrenergic receptor antagonists, and implanted cardiac defibrillators have improved survival. However, even with optimal medical and device management, heart failure is an inexorable disease associated with unacceptably high morbidity and mortality.1 Because the prevalence of CHF is high and the outlook dismal, new therapeutic approaches are needed. In gene transfer experiments, one generally studies how increased expression of a single molecule influences signal transduction and cardiac function. These studies have identified a large number of potential therapeutic targets in cardiac myocytes, including cell membrane receptors and their ligands, calcium handling proteins, intracellular signaling molecules, transcription factors, and contractile proteins in cardiac myocytes.5–9 An abundance of therapeutic candidates is thwarted by the Achilles’ heel of cardiovascular gene transfer—the paucity of evidence for a vector and delivery method that will provide adequate cardiac expression safely. The exuberance engendered by cardiovascular gene therapy has subsided over the last 10 years, supplanted by similar hopes for cell-based therapy. Bone marrow–derived cells, endothelial progenitor cells, and embryonic or mesenchymal stem cells have been used successfully in animal models,10,11 although debate continues regarding cardiac myocyte regeneration per se.12 Clinical trials using bone marrow–derived cells in patients with acute …
Structure and dynamics of metallic and carburized catalytic Ni nanoparticles: effects on growth of single-walled carbon nanotubes

Understanding the evolution of the catalyst structure and interactions with the nascent nanotube under typical chemical vapor deposition (CVD) conditions for the synthesis of single-walled carbon nanotubes is an essential step to discover a way to guide growth toward desired chiralities. We use density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulations on model metallic and carburized Ni clusters to explore changes in the fundamental features of the nanocatalyst: geometric and electronic structure, dynamics and stability of the carburized nanocatalyst, and interactions with nascent nanotube caps at two different temperatures (750 and 1000 K) and different carbon composition ratios. This allows us to gain insight about the evolution of these aspects during the pre-growth and growth stages of CVD synthesis of single-walled carbon nanotubes and their implications for reactivity and control of the nanotube structure.
Impact of the Health Insurance Portability and Accountability Act on Participant Recruitment and Retention

Recruiting and retaining an adequate sample is critical to the success of any research project involving humans. Recent reports indicate that the Health Insurance Portability and Accountability Act (HIPAA) privacy rule has adversely affected research. Few resources are available to help researchers navigate the challenges to recruitment and retention after HIPAA privacy rule implementation. This article addresses obstacles to recruitment in prospective clinical research studies related to the HIPAA privacy rule, as well as HIPAA-compliant strategies to enhance recruitment and retention. Recruitment challenges discussed include evolving interpretations of the HIPAA regulations, inability to directly contact potential participants, complexity of HIPAA-required documents, increased costs of recruitment, and an expanding administrative burden. Among the strategies addressed are preparatory research reviews, using clinical collaborators and staff liaisons, prescreening potential participants, minimizing participant burden during the consent process, enhancing participant follow-up, facilitating recruitment for future studies, and streamlining compliance training for staff.
Anatomy of an Intrusion

This insider's look at a real, sustained attack against a major, multinational corporation offers lessons learned about how to recognize an attack early, how to respond, and what to do to prevent future attacks.