cssi/SciSciGPT-SciSciNet huggingface dataset:
Relationships between the FastICA algorithm and the rayleigh quotient iteration

The FastICA algorithm is a popular procedure for independent component analysis and blind source separation. Recently, several of its convergence properties have been elucidated, including its average convergence performance and its finite-sample behavior. In this paper, we examine the kurtosis-based algorithm version for two-source mixtures with equal-kurtosis sources, proving that the single-unit FastICA algorithm has dynamical behavior that is identical to the Newton-based Rayleigh Quotient Iteration for finding an eigenvector of a symmetric matrix. We also derive a bound on the average inter-channel interference indicating that the initial convergence rate of FastICA is linear with a rate of (1/3). A simulation indicates its convergence performance.
Sodium boric acid: a Tris-free, cooler conductive medium for DNA electrophoresis

age (5−10 V/cm) runs necessary and highlights the limitations of using Tris as a cation for DNA electrophoresis. Another component of currently used buffers, EDTA, is now largely superfluous, since most DNA samples are readily soluble and since commonly used enzymes today would not carry an undesirable enzymatic activity under electrophoretic conditions.
Programming with miracles

In his seminal book, A Discipline of Programming [EWD 76], Dijkstra proposed that all sequential programs satisfy four laws for their weakest preconditions. By far the catchiest name was reserved for the Law of the Excluded Miracle, which captured the intuition that, started in a given state, a program execution must either terminate or loop forever. In the late 1980s, both Nelson [GN 89] and Morgan [CCM 90] noted that the law was unnecessarily restrictive when writing programs to be used as specifications. In the years since, "miracles" have become a standard feature in specification languages (for instance, the assume statement in JML [LLP+00] and BoogiePL [DL 05]). What is perhaps surprising is that miracles are not as commonly used in programs written as implementations. This is surprising because for many everyday tasks, programming in a language with miracles is often far superior to the popular scripting languages that are used instead. In this talk, we build upon pioneering work by Burrows and Nelson [GN 05] who designed the language LIM ("Language of the Included Miracle"). We describe a language LIMe ("LIM with extensions"), and discuss its application in the context of flight software testing, including the analysis of spacecraft telemetry logs.
MRI tissue classification with neighborhood statistics: a nonparametric, entropy-minimizing approach

We introduce a novel approach for magnetic resonance image (MRI) brain tissue classification by learning image neighborhood statistics from noisy input data using nonparametric density estimation. The method models images as random fields and relies on minimizing an entropy-based metric defined on high dimensional probability density functions. Combined with an atlas-based initialization, it is completely automatic. Experiments on real and simulated data demonstrate the advantages of the method in comparison to other approaches.
The effects of a minimum wage on employment outcomes: an application of regression discontinuity design

In this paper, I ask whether a minimum wage increase results in adverse employment outcomes in terms of work hours and the probability of gaining or retaining employment. Regression discontinuity design (rdd) is employed on a household-level panel survey dataset, using the minimum wage as the forcing variable that determines whether a sample is assigned to either the treatment group (minimum wage worker) or the control group (above minimum wage worker). The rdd graphs and the regressions seem to point to a negative effect of a higher minimum wage on work hours, not only for workers earning the minimum wage but also for workers earning 50 percent more than the minimum wage. The probability of gaining/retaining employment is lower for minimum wage workers and for workers earning 50 percent above the minimum wage. JEL Classification: J31
Oxidative treatment of high explosives contaminated wastewater

Abstract The oxidation of high explosives (HE), TNT, RDX and HMX, contaminated water has been studied under different conditions. Catalytic and advanced oxidation employing ultraviolet and hydrogen peroxide were investigated. Catalytic and non-catalytic wet oxidation of HE were carried over a 4.45 wt% Pt/TiO 2 catalyst with a particle diameter of less than 105 μ m in a batch reactor at moderate pressure (⩽35 atm) and temperature (⩽200°C). Ultraviolet photolysis in combination with hydrogen peroxide oxidation was carried out in a pyrex glass reactor with a total volume of 310 ml at ambient conditions. The irradiation in the photoreactor was obtained by a low-pressure mercury lamp that emits about 90% of its radiation at 254 nm with a 15 W power input. Catalytic and non-catalytic oxidation results indicate that the reaction rate is very much temperature dependent, virtually pressure independent, and mildly dependent on the amount of catalyst. The presence of catalyst resulted in about 20°C advantage in catalytic oxidation when compared to homogeneous wet oxidation. Also RDX/HMX oxidation was relatively easy without the presence of a catalyst at temperatures as low as 85°C and complete oxidation occurs at above 110°C in less than 30 min. Direct photolysis of RDX/HMX was accomplished in about 20 min whereas TNT was the most stable compound and the presence of hydrogen peroxide was essential to reach total oxidation in a reasonable time.
Nitrobenzimidazoles as inducers of glucose 6-phosphate dehydrogenase in Escherichia coli

Abstract Extracts of cultures of Escherichia coli B grown in the presence of nitrobenzimidazoles contain increased activity of glucose 6-phosphate dehydrogenase. The ratio of activity of glucose 6-phosphate dehydrogenase to the activity of 6-phosphogluconate dehydrogenase may be as high as 8, whereas the ratio for cultures not exposed to drugs is between 1 and 2. The magnitude and kind of effect of the drug depend on the position of the nitro group on the ring with position 4 more effective than 6. Another substituent on the 6-position modifies the effect of the 4-NO 2 so that the 4-NO 2 ,6-NH 2 benzimidazole was most effective in decreasing cell division without much effect on other parameters of growth, while the 4-NO 2 ,6-Cl benzimidazole was more toxic and also the most effective inducer of synthesis of glucose 6-phosphate dehydrogenase.
Sex Differences in Field Dependence-Independence between the Ages of 3 and 6

The present study analyzed sex differences in field dependence-independence between the ages of 3 and 6 yr., using the Preschool Embedded-figures Test. Results indicated that at age 5 girls were si...
A masking effect of urine from male dogs

Abstract Male dogs were given five separate two-way olfactory preference tests in which control urine from males was compared with: estrous urine; 75% estrous urine + 25% male urine; 50% estrous urine + 50% male urine; 25% estrous urine + 75% male urine; and 25% estrous urine + 75% water. The stimulus value of estrous urine was progressively decreased by the addition of increasing quantities of male urine. However, estrous urine still maintained a high stimulus value when it was diluted with an equivalent amount of water.
Intrathecal somatostatin, somatostatin analogs, substance P analog and dynorphin A cause comparable neurotoxicity in rats.

Abstract Rats chronically implanted with intrathecal catheters received intrathecal injections (10 μl followed by 10 μl saline flush) of either saline ( n = 5), somatostatin (100 μg, n = 10), the somatostatin analog BIM 23003 (100 μg, n = 5), the somatostatin analog SMS 201–995 (100 μg, n = 5), the substance P analog [ d -Pro 2 , d -Trp 7,9 ] SP (10 μg, n = 10), or dynorphin A (1–17) (20nmol, n = 8). These doses (somatostatin, substance P and dynorphin A) were selected based on previous studies in which they caused significant motor deficits. Effects on thermal cutaneous nociception, behavior, motor function and spinal cord histopathology were evaluated. All peptides caused severe neurotoxicity, evidenced by flaccid hind leg paralysis and lumbar spinal neuronal degeneration, which was accompanied by an inflammatory reaction in meninges and spinal gray matter. Histopathological changes had developed within 24 h after injection of somatostatin, substance P analog and dynorphin A, showing mild to severe neuronal degeneration and mild inflammatory responses in spinal cord and meninges. Significant antinociceptive effects, due to severe neurotoxic effects, were only observed following intrathecal injection of SMS 201–995 and the substance P analog. Potential neurotoxic mechanisms of the different peptides are discussed.
On future population.

Everything prior to Section 2.9 is in terms of aggregate births of the several years or other periods, considered as a time series. If each family made its decisions on having or not having children in relation to the conditions of the year, without reference to the number of children it has had in the past, nothing more need be said. But suppose now that couples aim at a certain number of children; good or bad times cause them to defer or to advance their childbearing, but not to change the total number. Then the fluctuations in the time series of births are less consequential; the drop of the birth rate in a depression would be made up in the subsequent business upswing, and the rate of increase of the population would be lower only insofar as older parents imply a greater length of generation. Constancy in the total number of children per family results in constancy in the average number of children per cohort, and the Bureau of the Census and the Scripps Foundation have taken advantage of this constancy in their projections.
Study on Commercial Scale Steam Explosion of Winter Brassica Napus STRAW

The lignocellulose-based rapeseed straw is usually burned. However, the presence of chlorine causes ash caking and potential risk of carcinogen formations. Because its natural form severely undergoes the anaerobic fermentation, it was subjected to various parameters of steam explosion technology. The dynamics of the processes were analyzed using the new parameter called Explosion Power Density, which was recently proposed to substitute the previously used Severity factor. However, it was proved that this parameter cannot embrace the complexity of the biotechnological process and should be accompanied by other operating parameters, for example, water content. The maximum yield of methane, 345.3 m3 tVS−1, was achieved in the vicinity of Explosion Power Density, 32 MWm−3, VS 9.9%, while the thermophilic conditions (50°C) allowed to reduce the time of anaerobic fermentation.
General-Relativistic Observables via Hamilton-Jacobi Functionals

By means of a canonical transformation, the Hamiltonian of general relativity can be made homogeneous in the momenta. Solutions of the corresponding Hamilton-Jacobi equations yield functionals of the configuration-space variables which are constant over equivalence classes generated by the constraints. The constancy of such solutions of the Hamilton-Jacobi equations is also a sufficient condition for infinitesimally neighboring sets of configuration variables to lie within the same four-dimensional space-time of the given family of Ricciflat manifolds.
Mode-pulling, mode-splitting and pulsing in a high gain He-Xe laser

Abstract High-gain, single-mode, helium-xenon lasers operating at 3.51 μm have been found to emit light in pulses rather than in a continuous wave. Two different pulsing regimes have been found, one correlated with oscillation in the vicinity of the Lamb dip and the other apparently due to mode splitting. Both instabilities require high gain and relatively low homogeneous broadening to be observed.
Analytical Modeling and Experimental Verification of the Vibrations of the Zigzag Microstructure for Energy Harvesting

This paper addresses an issue in energy harvesting that has plagued the potential use of harvesting through the piezoelectric effect at the micro-electro-mechanical systems (MEMS) scale. Effective energy harvesting devices typically consist of a cantilever beam substrate coated with a thin layer of piezoceramic material and fixed with a tip mass tuned to resonant at the dominant frequency of the ambient vibration. The fundamental natural frequency of a beam increases as its length decreases, so that at the MEMS scale the resonance condition occurs orders of magnitude higher than ambient vibration frequencies, rendering the harvester ineffective. Here, we propose a new geometry for MEMS scale cantilever harvesters with low fundamental frequencies. A "zigzag" geometry is proposed, modeled, and solved to show that such a structure would be able to vibrate near resonance at the MEMS scale. An analytical solution is presented and verified against Rayleigh's method and is validated against a macroscale experiment. The analysis is used to provide design guidelines and parametric studies for constructing an effective MEMS scale energy harvesting device in the frequency range common to low frequency ambient vibrations, removing a current barrier.
Generation of CD8 (T8) cytotoxic cells has a preferential requirement for CD4+2H4- inducer cells.

Abstract CD8 (T8) cells are capable of both suppression and cytotoxicity. However, we have found that the activation of CD8 cytotoxic cells has a preferential requirement for a different CD4 (T4) subset from that previously reported for the activation of CD8 suppressor cells. We have recently characterized two monoclonal antibodies which subdivide CD4 cells into inducers of help for antibody production (CD4 + 4B4 + ) and inducers of CD8 mediated suppression (CD4 + 2H4 + ). We now report that CD4 + 4B4 + 2H4 − cells also preferentially induce CD8-mediated cytotoxicity. Human peripheral blood T cells were fractionated into CD8, CD4, CD4 + 2H4 + , and CD4 + 2H4 − populations by both the adherence to antibody-coated plates and the fluorescence-activated cell sorter. The cells were cultured 6 days with irradiated allogeneic non-T cells and a cytotoxicity assay was then performed using cryopreserved non-T cells as targets. It was found that the combination of CD4 + 2H4 − cells and CD8 cells resulted in greater cytotoxicity than either CD4 + CD8, or CD4 + 2H4 + + CD8. The combination of CD4 + 2H4 + cells with CD8 cells resulted in minimal cytotoxicity, which was similar to that generated by CD8 cells alone. These results were confirmed using anti-4B4 to positively select the reciprocal CD4 subset. Furthermore, the cytotoxicity induced by CD4 + 2H4 − cells was alloantigen specific and Class I major histocompatibility complex restricted. As both CD4 + 2H4 + and CD4 + 2H4 − cells proliferate equally well to alloantigen and produce similar levels of interleukin 2 (IL-2), it is likely that the generation of CD8 cytotoxic cells requires a signal in addition to IL-2.
Synthesis of a site-specific DNA-binding peptide

The Hin recombinase binds to specific sites on DNA and mediates a recombination event that results in DNA inversion. In order to define the DNA-binding domain of the Hin protein two peptides 31 and 52 amino acids long were synthesized. Even though the 31mer encompassed the sequence encoding the putative helix-coil-helix-binding domain, it was not sufficient for binding to the 26-base pair DNA crossover site. However, the 52mer specifically interacted with the site and also effectively inhibited the Hin-mediated recombination reaction. The 52mer bound effectively to both the 26-base pair complete site and to a 14-base pair "half site." Nuclease and chemical protection studies with the 52mer helped to define the DNA base pairs that contributed to the specificity of binding. The synthetic peptide provides opportunities for new approaches to the study of the nature of protein-DNA interaction.
Effects of Tidal Stage and Sun Angles on Intertidal Benthic Microalgal Productivity

Motile benthic diatoms exhibit rhythmlc vertical migrations that are influenced by tidal and llght cycles. As a consequence of these periodlc migrations, corresponding periodicities in benthic microalgal production should occur. Using oxygen microelectrodes, hourly measurements of microalgal production were obtained from subaerially exposed cores collected from low-intertidal muddy sediments in North Inlet estuary, South Carolina, USA Microalgal productivity at low tide was twce that at high tlde (mean difference 52 %) and was significantly correlated with diurnal and tidal periodicities (r2 = 0.41; p < 0.0001). Production values ranged from 28.0 to 460.5 pm01 O2 mg chl a-' h' and maximum rates were achieved during mid-afternoon low tides. A curvilinear regression equation was constructed to simulate daily and monthly benthic microalgal production based on tidal and light cycles. Comparisons between predictions of the curvilinear equation and published data sets showed a reasonable agreement (r2 = 0.77), suggesting similar phenomena in other estuaries. Current benthic microalgal production models do not account for hourly variability in productivity, leading to potentially large errors when measurements are extrapolated over monthly and annual time scales. Although other physiological and abiotic factors also influence benthic microalgal productivity, much of the short-term variability in production rates may be simply attributed to migratory rhythms within estuarine sediments.
A Complement of Ten Essential and Pleiotropic Arabidopsis COP/DET/FUS Genes Is Necessary for Repression of Photomorphogenesis in Darkness

Two genetic screens, one for mutations resulting in photomorphogenic development in darkness and the other for mutants with fusca phenotype, have thus far identified six pleiotropic Arabidopsis COP/DET/FUS genes. Here, we characterized representative mutants that define four additional pleiotropic photomorphogenic loci and a null mutant allele of the previously defined DET1 locus. Dark-grown seedlings homozygous for these recessive mutations exhibit short hypocotyls and expanded cotyledons and are lethal before reaching reproductive development. Dark-grown mutant seedlings also display characteristic photomorphogenic cellular differentiation and elevated expression of light-inducible genes. In addition, analyses of plastids from dark-grown mutants reveal partial chloroplast differentiation and absence of etioplast development. Root vascular bundle cells of light-grown mutant seedlings develop chloroplasts, suggesting that these FUS gene products are important for suppression of chloroplast differentiation in light-grown roots. Double-mutant analyses indicate that these pleiotropic cop/det/fus mutations are epistatic to mutations in phytochromes, a blue-light photoreceptor, and a downstream regulatory component, HY5. Therefore, there is a complement of at least 10 essential and pleiotropic Arabidopsis genes that are necessary for repression of photomorphogenic development.
Genome-wide remodeling of the epigenetic landscape during myogenic differentiation

We have examined changes in the chromatin landscape during muscle differentiation by mapping the genome-wide location of ten key histone marks and transcription factors in mouse myoblasts and terminally differentiated myotubes, providing an exceptionally rich dataset that has enabled discovery of key epigenetic changes underlying myogenesis. Using this compendium, we focused on a well-known repressive mark, histone H3 lysine 27 trimethylation, and identified novel regulatory elements flanking the myogenin gene that function as a key differentiation-dependent switch during myogenesis. Next, we examined the role of Polycomb-mediated H3K27 methylation in gene repression by systematically ablating components of both PRC1 and PRC2 complexes. Surprisingly, we found mechanistic differences between transient and permanent repression of muscle differentiation and lineage commitment genes and observed that the loss of PRC1 and PRC2 components produced opposing differentiation defects. These phenotypes illustrate striking differences as compared to embryonic stem cell differentiation and suggest that PRC1 and PRC2 do not operate sequentially in muscle cells. Our studies of PRC1 occupancy also suggested a “fail-safe” mechanism, whereby PRC1/Bmi1 concentrates at genes specifying nonmuscle lineages, helping to retain H3K27me3 in the face of declining Ezh2-mediated methyltransferase activity in differentiated cells.
Hyperprogesteronemia in response to Vitex fischeri consumption in wild chimpanzees (Pan troglodytes schweinfurthii)

Chimpanzees in Gombe National Park consume fruits of Vitex fischeri during a short annual fruiting season. This fruit species is a member of a genus widely studied for phytoestrogen composition and varied physiological effects. One particularly well-studied species, V. agnus-castus, is noted for its documented effects on female reproductive function, evidenced in increased progesterone levels and consequent regulation of luteal function. We examined reproductive hormone levels in both male and female chimpanzees during a 6-week period of intense V. fischeri consumption. V. fischeri consumption was associated with an abrupt and dramatic increase in urinary progesterone levels of female chimpanzees to levels far exceeding the normal range of variation. Female estrogen levels were not significantly impacted, nor were male testosterone levels. These are some of the first data indicating that phytochemicals in the natural diet of a primate can have significant impacts on the endocrine system, though the fluctuating nature of chimpanzee diet and reproductive function does not allow us to determine whether the effects observed during this short period had a broader positive or negative impact on female fertility. Given the widespread use of various Vitex species by African primates and the as-yet-undescribed phytochemical properties of these species, we predict that our observations may be indicative of a broader phenomenon.
Ultrasonography of the normal fetal brain

Since the early 1960s it has been possible to identify the fetal head using A-mode ultrasound. The introduction of high-resolution, real-time, grayscale ultrasound in the mid-to-late 1970s first enabled the routine display of subtle internal anatomy. Using presently available equipment, the fetus can be imaged from 7 weeks after the last menstrual period until term and the internal anatomy of the fetal head can be detected after 11–12 weeks. The ultrasonic anatomy of the normal fetal head throughout the second and third trimesters is discussed, as are the normal changes taking place with growth.
Comparison of the structure of amorphous Ge and GaAs

Abstract The radial distribution functions of amorphous Ge and GaAs have been determined by X-ray diffraction with sufficient accuracy to reliably establish, for the first time, differences in the two structures. The staggered configuration is found to be favored in both structures, but much more so in amorphous GaAs than in amorphous Ge. This result is interpreted, using structural models, as also implying a difference in ring statistics, with a negligible fraction of 5-membered rings in amorphous GaAs.
Following the standard form: Effects of equation format on algebraic modeling

When people construct algebraic equations to represent quantitative relations, they often reverse the roles of the variables (6S = P instead of 6P = S). Results from three experiments show that a major reason for such reversal errors is people’s adherence to, and interpretation of, the Standard Form of algebraic models. College students constructed, selected, and interpreted algebraic models that either had the standard multiplication format (MF: ax = y), or the mathematically equivalent division format (DF: y/a = x). A large minority of participants constructed reversed MF models, whereas most participants who were instructed to use DF equations constructed correct models (Experiment 1). Most participants understood that MF and DF models of the same relation should be mathematically equivalent (Experiment 2), but they drew a conceptual distinction between these models (Experiment 3). The authors discuss the impact of notational conventions on people’s interpretation and use of representational tools.
Traveling waves in rotating Rayleigh-Bénard convection.

A combined analytical, numerical, and experimental study of the traveling-wave wall mode in rotating Rayleigh-Benard convection is presented. No-slip top and bottom boundary conditions are used for the numerical computation of the linear stability, and the coefficients of the linear complex Ginzburg-Landau equation are then computed for various rotation rates. Numerical results for the no-slip boundary conditions are compared with free-slip calculations and with experimental data, and detailed comparison is made at a dimensionless rotation rate Omega=274. It is found that the inclusion of the more realistic no-slip boundary conditions for the top and bottom surfaces brings the numerical linear stability analysis into better agreement with the experimental data compared with results using free-slip top/bottom boundary conditions. Some remaining discrepancies may be accounted for by the finite conductivity of the sidewall boundaries.
Quantitative anatomic measures and comorbid medical illness in late- life major depression

The authors examined the individual and relative roles of atrophy, comorbid medical illness, and cerebrovascular risk factors in the pathogenesis of late-life major depressive disorder (MDD). They used magnetic resonance imaging techniques to study 28 subjects with late-life MDD, 29 healthy control subjects, and 34 subjects with probable dementia of the Alzheimer type (DAT). Depressed subjects showed increases in cerebrospinal fluid volumes comparable to the DAT group but significantly different from control subjects. High-intensity signals, but not measures of atrophy correlated significantly with cerebrovascular risk factor scores. A logistic regression revealed that both brain atrophy and medical illness are associated with an increased risk of developing MDD. Data suggest that both atrophy and comorbid medical illness increase the likelihood of developing MDD in late life.
Oocyte activation in the marine shrimp, Sicyonia ingentis

The resumption of meiotic maturation and formation of the hatching envelope in the ova of the marine shrimp, Sicyonia ingentis were triggered by exposure to seawater. Fertilized and unfertilized ova underwent the same sequence of events; however, a slightly longer time was required for the completion of meiotic maturation and hatching envelope formation in unfertilized ova. The hatching envelopes formed in both cases were structually identical. Activation of unfertilized ova, but not fertilized ova, depended on external Ca++. If unfertilized ova that formed neither polar bodies nor a hatching envelope in Ca++-free seawater were transferred to normal seawater, activation resumed. External Mg++ was necessary for both fertilized and unfertilized ova to undergo activation.
Low-frequency electric microfield distributions in plasmas.

We evaluate the low-frequency component electric microfield distribution at a charged point, i.e., the field distribution due to ions, possibly of different species, which interact through an electron-screened potential. The method employed is an adaptation of the adjustable-parameter exponential (APEX) approximation previously developed for the high-frequency component and involves a noninteracting-quasiparticle representation of the electron-screened ions designed to yield the correct second moment of the microfield distribution. The APEX results are compared to Monte Carlo simulations, and we find good agreement.
Effects of temperature on fruit thinning with ethephon in ‘Golden Delicious’ apples

Abstract The effect of temperature on the ability of 2-chloroethylphosphonic acid (ethephon), when applied at 20 mm stage of fruit development, to induce ethylene evolution of fruit and leaves and abscission of fruit and leaves was determined using 9-year-old root-bagged ‘Golden Delicious’/M.27 apple ( Malus domestica Borkh.) trees in environment-controlled growth rooms. Ethephon at 400 μL L −1 effectively thinned apples, and its thinning effect was not affected by increasing day/night temperature from 21.1/10 to 32.2/21.1 °C. Fruit ethylene evolution was enhanced by application of ethephon. Peak fruit ethylene evolution occurred 1 day after application of ethephon when day/night temperature was 32.2/21.1 °C whereas it occurred 2 days after application of ethephon at a day/night temperature of 21.1/10 or 26.7/15.6 °C. Ethephon increased leaf ethylene evolution drastically but it did not induce leaf abscission regardless of temperature.
The chemisorption of Co on Rh(111)

Abstract The adsorption of CO on Rh(111) has been studied by thermal desorption mass spectrometry and low-energy electron diffraction (LEED). At temperatures below 180 K, CO adsorbs via a mobile precursor mechanism with sticking coefficient near unity. The activation energy for first-order CO desorption is 31.6 kcal/mole (νd = 1013.6s−1) in the limit of zero coverage. As CO coverage increases, a (√3 ×√3)R30u overlayer is produced and then destroyed with subsequent formation of an overlayer yielding a (2 × 2) LEED pattern in the full coverage limit. These LEED observations allow the absolute assignment of the full CO coverage as 0.75 CO molecules per surface Rh atom. The limiting LEED behavior suggests that at full CO coverage two CO binding states are present together.
Negative differential conductance in strained Si point contacts and wires

The observation of negative differential conductance (NDC) in simple nanostructure geometries fabricated on high-mobility Si/SiGe strained-layer heterostructures is reported. The NDC is observed in the drain characteristic of etch-defined “point contacts” with lithographic width and length of 0.22, and 0.12 μm, respectively. Current peak-to-valley ratios as large as 2.0 are observed at T=1.3 K. The NDC is also observed in “wire” geometries as long as 19 μm, and can persist to temperatures as high as 83 K, with a minimum in the differential conductance observable at 103 K. The NDC in long wires is accompanied by the formation of a high-field domain at the drain end of the wire. The effect is only observed in laterally constricted geometries, but is not a result of quantum confinement or impurity-related trapping. We suggest that the NDC and the attendant domain formation are caused by phonon emission by hot electrons within the constricted geometry.
A New Differential Analyzer

This paper describes a new 14-integrator differential analyzer recently placed in service by the General Electric Company at Schenectady. This analyzer has a mechanical interconnection system but has integrators of novel design in that a Polaroid follow-up system is used rather than the more usual mechanical torque amplifiers.
Effects of Postural Support on Eye Hand Interactions across Development

Reaching to grasp an object of interest requires a complex sensorimotor transformation-involving eye, head, hand, and postural systems. We show here that discontinuities in development of movement in these systems are dependent not only on age but also vary according to task constraints. Providing external postural support allows us to examine the differential influences of the eye on the hand and the hand on the eye as the ability to isolate and coordinate each system changes with age. Children 4–6 years old had significant difficulty isolating eye movement from head or hand movement, whereas children 7–9 years old showed improved ability to isolate the eye, and by 10–15 years children became proficient in isolating hand movements from eye movements. Postural support had differential effects on the processes of initiation and execution of eye–hand movements. The addition of postural support decreased the time needed for planning the movement, especially in the youngest children, and contributed to increased speed of isolated movements, whereas it caused differential slowing of coordinated movements depending on the child’s developmental level. We suggest that the complexity of the results reflects the complexity of changing task requirements as children transition from simpler ballistic control of all systems to flexible, independent but coordinated control of multiple systems.
A markov routing algorithm for mobile DTNs based on spatio-temporal modeling of human movement data

Store-carry-forward communication, which is set as the heart of all routing protocols for mobile disruption-tolerant networks (DTNs), exploits nodes' mobility to bring messages closer to their destinations by exchanging messages across mobile nodes when they meet in close proximity. Understanding the subtle characteristics of human mobility leads to better service and application provisioning for mobile DTNs. We use GPS traces collected from multiple mobile users to empirically study different aspects of human mobility. Various Markov models (first, second and third-order) are estimated from users' mobility data. Based on empirical evidence, second-order Markov models are deemed sufficient to estimate mobile users' future locations accurately. These Markov models permit the design of a new routing algorithm for mobile DTNs capable of more efficiently routing data objects to their destination locations. The relay selection in this routing algorithm is based on mobile users' absorption times to the destination location. Simulations show that the proposed routing algorithm consumes less energy than legacy epidemic routing algorithms without excessive transmission delays.
The Polya algorithm for convex approximation

Abstract Let X = C[0, 1] and let b be the set of continuous convex functions on [0, 1]. If ƒ ϵ X , then the set μ∞(ƒ∣ C ) of all best L∞-approximants to ƒ from b is not empty and may contain more than one element. In this paper we define an element ƒ∗ in μ∞(ƒ∣ C called the strict approximation to ƒ from b , and we show that lim p → ∞ ƒ p (x) = ƒ ∗ (x) for all x in [0, 1], where ƒp is the unique best Lp-approximant to ƒ from b . We then establish the continuity of the mapping ƒ → ƒ∗. Finally, we show that if ƒ, g ϵ X are uniformly close on [0, 1], and if I is a closed subinterval of (0, 1), then ƒp and gp are uniformly close on I for p ⩾ 1.
The Lack of Synchronization between Iron Uptake and Cell Growth Leads to Iron Overload in Saccharomyces cerevisiae during Post-exponential Growth Modes

Fermenting cells growing exponentially on rich (YPAD) medium underwent a transition to a slow-growing state as glucose levels declined and their metabolism shifted to respiration. During exponential growth, Fe import and cell-growth rates were matched, affording an approximately invariant cellular Fe concentration. During the transition period, the high-affinity Fe import rate declined slower than the cell-growth rate declined, causing Fe to accumulate, initially as FeIII oxyhydroxide nanoparticles but eventually as mitochondrial and vacuolar Fe. Once the cells had reached slow-growth mode, Fe import and cell-growth rates were again matched, and the cellular Fe concentration was again approximately invariant. Fermenting cells grown on minimal medium (MM) grew more slowly during the exponential phase and underwent a transition to a true stationary state as glucose levels declined. The Fe concentration of MM cells that just entered the stationary state was similar to that of YPAD cells, but MM cells continu...
Emerging cyberinfrastructure: Challenges for the chemical process control community

Abstract This paper considers a broad, high-level overview of two key trends in “emerging cyberinfrastructure”: how it is nearing a tipping point of “information flow reversal” of data flowing from the periphery of the internet to the core (instead of the historic “download” model of data flow from the core to the periphery) and the coupling of all traditional infrastructures such as roads and power grids to cyberhubs with the incorporation of smart features such as sensors and actuators. In the language of the CPC community, the cyberinfrastructure for data flow is evolving from an isolated and simple open-loop system to a closed-loop system of complex inter-dependencies with all other infrastructures. This pathway will undoubtedly lead to one of the grand challenges of modern systems engineering, namely a system with a rich set of dynamics that presents a formidable challenge amenable only to those most skilled in the art and science of process control. The dramatic ramp up in societal investments in radio frequency identification (RFID), the emergence of a community investigating dynamic data-drive application systems (DDDAS) and mitigation of security risks engendered by cyberhubs linking critical infrastructures can all be reconsidered in this framework as part of a greater pattern.
Retrieval of thin ice thickness from multifrequency polarimetric SAR data

We discuss the observed C- and L-band polarimetric signatures of thin lead ice in one Synthetic Aperture Radar image based on the expected ice properties and results from a scattering model.
Probability Statistics, and Reliability for Engineers

Introduction: Introduction. - Types of Uncertainty. - Taylor Series Expansion. - Applications. - Problems. - Data Description and Treatment: Introduction.- Classification of Data. - Graphical Description of Data. - Histograms and Frequency Diagrams. - Descriptive Measures. - Applications. - Problems. - Fundamentals Of Probability: Introduction. - Sample Spaces, Sets, and Events. - Mathematics of Probability. - Random Variables and Their Probability Distributions. - Moment.- Common Discrete Probability Distributions. - Common Continuous Probability Distributions. - Applications. - Problems. - Multiple Random Variables: Introduction. - Joint Random Variables and Their Probability Distributions. - Functions of Random Variables. - Applications. - Problems. - Fundamentals of Statistical Analysis: Introduction. - Estimation of Parameters. - Sampling Distributions. - Hypothesis Testing: Procedure. - Hypothesis Tests of Means. - Hypothesis Tests of Variances. - Confidence Intervals. - Sample-Size Determination. - Selection of Model Probability Distributions. - Applications. Problems. - Curve Fitting and Regression Analysis: Introduction. - Correlation Analysis. - Introduction to Regression. - Principle of Least Squares. - Reliability of the Regression Equation. - Reliability of Point Estimates of the Regression Coefficients. - Confidence Intervals of the Regression Equation. - Correlation Versus Regression. - Applications of Bivariate Regression Analysis. - Multiple Regression Analysis. - Regression Analysis of Nonlinear Models. - Applications. Problems. - Simulation: Introduction. - Monte Carlo Simulation. - Random Numbers. - Generation of Random Variables. - Generation of Selected Discrete Random Variables. - Generation of Selected Continuous Random Variables. - Applications. - Problems. - Reliability and Risk Analysis: Introduction. - Time to Failure. - Reliability of Components. - Reliability of Systems. - Risk-Based Decision Analysis. - Applications. - Problems. - Bayesian Methods: Introduction. - Bayesian Probabilities. - Bayesian Estimation of Parameters. - Bayesian Statistics. - Applications. - Problems. - Appendix A: Probability and Statistics Tables. - Appendix B: Values of the Gamma Function. - Subject Index.
Plastisols as a surface coating

Vinyls are noted for their excellent physical properties including flexibility, toughness, unlimited color selection, and abrasion and chemical resistance. Vinyl plastisols combine these properties with the ease of liquidapplication. Plastisols are dispersions of fine particle size polyvinyl chloride (PVC) resins in plasticizing liquids. In addition to the resins and plasticizers, heat or light stabilizers, color pigments, flame retardants, blowing agents, or other additives may be included as determined by the intended end use. Plastisols may be fused in relatively thick sections without concern for solvent or water blistering; they are commonly referred to as 100% solids materials. Organosols are closely related to plastisols. Simply stated, they are plastisols to which a volatile solvent or thinner has been added. Their utility arises from being able to use a liquid to apply a hard, tough film, in thickness generally limited to under 15 mils. Organosols may be applied in many decorative finishes such as matted, textured, or hammer tone.
Hydroelastic response and energy harvesting potential of flexible piezoelectric beams in viscous flow

Electroactive polymers such as piezoelectric elements are able to generate electric potential differences from induced mechanical deformations. They can be used to build devices to harvest ambient energy from natural flow-induced deformations, e.g., as flapping flags subject to flowing wind or artificial seaweed subject to waves or underwater currents. The objectives of this study are to (1) investigate the transient hydroelastic response and energy harvesting potential of flexible piezoelectric beams fluttering in incompressible, viscous flow, and (2) identify critical non-dimensional parameters that govern the response of piezoelectric beams fluttering in viscous flow. The fluid-structure interaction response is simulated using an immersed boundary approach coupled with a finite volume solver for incompressible, viscous flow. The effects of large beam deformation, membrane tension, and coupled electromechanical responses are all considered. Validation studies are shown for the motion of a flexible filam...
Activation of dopamine neurons is critical for aversive conditioning and prevention of generalized anxiety

Generalized anxiety is thought to result, in part, from impairments in contingency awareness during conditioning to cues that predict aversive or fearful outcomes. Dopamine neurons of the ventral midbrain exhibit heterogeneous responses to aversive stimuli that are thought to provide a critical modulatory signal to facilitate orientation to environmental changes and assignment of motivational value to unexpected events. Here we describe a mouse model in which activation of dopamine neurons in response to an aversive stimulus is attenuated by conditional genetic inactivation of functional NMDA receptors on dopamine neurons. We discovered that altering the magnitude of excitatory responses by dopamine neurons in response to an aversive stimulus was associated with impaired conditioning to a cue that predicts an aversive outcome. Impaired conditioning by these mice was associated with the development of a persistent, generalized anxiety-like phenotype. These data are consistent with a role for dopamine in facilitating contingency awareness that is critical for the prevention of generalized anxiety.
Breakup of liquid threads in linear flows

Abstract We study, theoretically, the surface-tension-driven breakup of a long filament of fluid in a general linear flow, v = L·x. By analyzing the problem in a moving frame and assuming a circular cross section we find that the flow around the filament is an axisymmetric extensional flow with a time-dependent strength, which can be calculated from the rate of rotation of the filament and a contribution to the axial velocity which varies with the azimuthal angle. The analysis of the axisymmetric time-dependent case does not appear to be overly restrictive: the asymmetric variation may be small even in the case of a simple shear flow, in which the asymmetry is the greatest among all possible linear flows, depending on the initial orientation of the filament. We present calculations for two special cases: hyperbolic extensional flow and simple shear flow. The results indicate that under similar conditions, the drop fragments produced on breakup in simple shear flow are larger than those in hyperbolic extensional flow. The predictions of the theory also compare reasonably well with some previous experimental data in hyperbolic extensional flow and simple shear flow.
Growth of dorsal spinocerebellar axons through a lesion of their spinal pathway during early development in the North American opossum, Didelphis virginiana.

Abstract Supraspinal axons grow around or through lesions of their spinal pathway during specific critical periods of mammalian development, but comparable plasticity has not been documented for axons which form ascending tracts. In the present study, we asked whether axons of the dorsal spinocerebellar tract (DSCT) are capable of such growth. The spinal cord of the North American opossum, Didelphis virginiana, was hemisected at mid-thoracic levels between postnatal day (PD) 5 and 68 and after varying survival times, bilateral injections of Fluoro-Gold or Fast Blue were made into the anterior lobe of the cerebellum, the major target of DSCT axons. Seven days later, the pups were sacrificed and their spinal cord processed for fluorescence microscopy. In animals lesioned between PD5 and 9, and allowed to survive for 37–269 days, neurons were labeled bilaterally in Clarke's nucleus (CN) caudal to the lesion, but they were fewest in number and smallest in size on the lesioned side. Since the DSCT originates almost entirely within CN on the ipsilateral side, we conclude that the neurons labeled ipsilateral and caudal to the lesion supported axons which grew around or through it. Histological examination revealed that recognizable spinal cord was present at the lesion site and that labeled spinocerebellar axons were located in their normal position ipsilateral to the lesion. It appears, therefore, that growth occurred through the lesion. In animals lesioned between PD13 and 68, labeled neurons were not found in CN caudal and ipsilateral to the lesion although they were present on the contralateral (control) side. We conclude that DSCT axons, like axons which form descending tracts, grow through a lesion of their spinal pathway if it is made early in development.
Effect of storage of cassava roots on the chemical composition and sensory qualities of gari and fufu

Abstract The effect of storage of cassava roots (TMS 30572), at ambient temperature for 0–4 days, on percentage yield, chemical composition and sensory qualities of gari and fufu was investigated. Acidity of cassava roots did not change appreciably during storage, but moisture and cyanide contents decreased by 3·2 and 7·7%, respectively. Storage of cassava roots led to a reduction in cyanide content of gari and fufu. It also reduced the percentage yield of gari and fufu by 49·9 and 60·3, respectively. Moisture content, pH and acidity of gari and fufu, however, remained fairly constant irrespective of the length of storage of cassava roots. Also, acidity increased while cyanide content decreased during fermentation of gari and fufu mash. Storage of cassava roots was found to have no significant effect on the organoleptic qualities of gari and fufu.
The Future of Export Controls: Developing New Strategies for Nonproliferation

Export controls remain an important instrument to international nonproliferation efforts in that they raise the cost of weapons of mass destruction (WMD) acquisition and development, buy time, and deny known and potential proliferant actors easy access to items and technologies that are either indispensable to WMD development or can make critical differences in existing arsenals. However, making export controls effective requires strengthening both multilateral export control regimes and national export control systems; shifting away from only focusing on selected items/technologies to greater attention to potential destabilizing military applications in prospective end-user(s)/end-use; and, better and more regular intelligence and information sharing. Export controls based on the mission/mandates of existing international nonproliferation regimes such as the Treaty on the Nonproliferation of Nuclear Weapons (NPT) and Chemical Weapons Convention (CWC) will have greater legitimacy and therefore relatively more ready acceptance among exporters and importers alike.