cssi/SciSciGPT-SciSciNet huggingface dataset:
Autochthonous leaf assemblages as records of deciduous forest communities: An actualistic study

How well do autochthonous leaf assemblages reflect live plant communities? How do leaf assemblages accumulating over different time scales compare in paleoecologic information content? Forest-floor leaf assemblages accumulating over ten-day intervals (referred to here as short-term assemblages) and over a five-month season of leaf abscission (referred to here as a long-term assemblage) were compared with the surrounding community in a modern temperate deciduous forest in northern Ohio. Leaf number in the long-term leaf assemblage is strongly correlated with the abundance of taxa (stem number) around the accumulation site and weakly correlated with both average taxon size (stem circumference) and average taxon distance from the accumulation site. Of the variance in leaf number, 45% is explained solely by stem number and 67% by stem number and average distance together. Average size explains an insignificant amount of the variance in leaf number. Like the long-term assemblage, leaf number in the short-term leaf assemblages is usually strongly correlated with stem number and usually weakly correlated with average taxon size and average taxon distance. However, these patterns are not consistent, and the correlations are highly variable. Similarly, there is high variability in the degree to which stem number, average taxon size and average taxon distance account for variance in leaf number. Short-term leaf assemblages are characterized by great fluctuations in taxonomic relative abundance, caused by seasonal variation in the timing and rate of leaf abscission among taxa. While autochthonous leaf assemblages accumulating over several months can reflect the surrounding community with fair accuracy, leaf assemblages accumulating over shorter time spans are inconsistent records of the surrounding community. The depositional circumstances producing short-term assemblages (i.e. event burial) may result in well-preserved specimens, but community data from such assemblages should be treated with caution and, if possible, compared with data from contemporaneous long-term assemblages.Paleobotany, taphonomy, actualism, paleocommunity reconstruction, time-averaging. Keith H. Meldahl, Damon Scott and Karen Carney, Department of Geology, Oberlin College, Oberlin, Ohio, 44074, USA; 6th June, 1994; revised 8th February, 1995.
Independent origins of New Zealand moas and kiwis

Two groups of flightless ratite birds existed in New Zealand during the Pleistocene: the kiwis and the moas. The latter are now extinct but formerly included 11 species. We have enzymatically amplified and sequenced approximately 400 base pairs of the mitochondrial 12S rRNA gene from bones and soft tissue remains of four species of moas as well as eight other species of ratite birds and a tinamou. Contrary to expectation, the phylogenetic analysis shows that the kiwis are more closely related to Australian and African ratities than to the moas. Thus, New Zealand probably was colonized twice by ancestors of ratite birds.
New Developments in the Use of Histamine and Histamine Receptors

Histamine and the histamine receptors are important regulators of a plethora of biological processes, including immediate hypersensitivity reactions and acid secretion in the stomach. In these roles, antihistamines have found widespread therapeutic applications, while the last receptor to be discovered, the H4 histamine receptor, has become a major target of novel therapeutics. Recent studies involving human genetic variance and the development of mice lacking specific receptors or the ability to generate histamine have shown roles for the histamine pathway that extend well beyond the established roles. These include identification of previously unappreciated mechanisms through which histamine regulates inflammation in allergy, as well as roles in autoimmunity, infection, and pain. As a result, antihistamines may have wider applications in the future than previously predicted.
An overview of the quantitative influence of several risk factors on progression of atherosclerosis in young people in the United States

This overview of the National Institutes of Health-supported, multicenter, investigator-initiated study of the Pathobiological Determinants of Atherosclerosis in Youth (PDAY) is designed to summarize the plan, approaches, and the expanding contribution of this unique research program, which is now in its tenth year. It traces for the first time the development, the organization, and the function of the many new features and facets that are being used to yield needed information on the relationships between the classic risk factors and the topography, severity, and the cellular and chemical reactions that influence the development of the early raised plaques. It has also helped establish the factors that influence the progression of the four major types of intermediate raised lesions that grossly are all similar, well delineated fatty plaques. Most of the observations are quantitative. A few glimpses into the unique findings that have been published are presented.
Fisetin inhibits growth, induces G2/M arrest and apoptosis of human epidermoid carcinoma A431 cells: role of mitochondrial membrane potential disruption and consequent caspases activation

Non-melanoma skin cancers (NMSCs), one of the most common neoplasms, cause serious morbidity and mortality. Therefore, identification of non-toxic phytochemicals for prevention/treatment of NMSCs is highly desirable. Fisetin (3,3',4',7-tetrahydroxyflavone), a dietary flavonoid, present in fruits and vegetables possesses anti-oxidant and antiproliferative properties. The aim of this study was to investigate the chemotherapeutic potential of fisetin in cultured human epidermoid carcinoma A431 cells. Treatment of A431 cells with fisetin (5-80 μm) resulted in a significant decrease in cell viability in a dose- and time-dependent manner. Employing clonogenic assay, we found that fisetin treatment significantly reduced colony formation in A431 cells. Fisetin treatment of A431 cells resulted in G₂ /M arrest and induction of apoptosis. Furthermore, treatment of A431 cells with fisetin resulted in (i) decreased expression of anti-apoptotic proteins (Bcl2; Bcl-xL and Mcl-1); (ii) increased expression of pro-apoptotic proteins (Bax, Bak and Bad); (iii) disruption of mitochondrial potential; (iv) release of cytochrome c and Smac/DIABLO from mitochondria; (v) activation of caspases; and (vi) cleavage of Poly(ADP-ribose) polymerase (PARP) protein. Pretreatment of A431 cells with the pan-caspase inhibitor (Z-VAD-FMK) blocked fisetin-induced cleavage of caspases and PARP. Taken together, these data provide evidence that fisetin possesses chemotherapeutic potential against human epidermoid carcinoma A431 cells. Overall, these results suggest that fisetin could be developed as a novel therapeutic agent for the management of NMSCs.
Rootstock/scion relations in horticultural crop physiology

Abstract A preliminary report is made of the results of growth studies on compound trees formed of all combinations, as scion and as rootstock, of three clones, chosen to cover a wide range of vigour, of apple, quince, and cherry. Under the conditions of the orchard experiment and with the clones used, no distinction was found between influence on tree size of any apple clone when present as the scion or when present as the rootstock. Major distinctions in influence as scion or as rootstock were, however, found in the case of certain quince and cherry clones. Evidence as to the precocity of flowering of the scions of compound trees indicates that precocity may occur independently of a dwarfing influence.
Psilocybin dose-dependently causes delayed, transient headaches in healthy volunteers

Background Psilocybin is a well-characterized classic hallucinogen (psychedelic) with a long history of religious use by indigenous cultures, and nonmedical use in modern societies. Although psilocybin is structurally related to migraine medications, and case studies suggest that psilocybin may be efficacious in treatment of cluster headache, little is known about the relationship between psilocybin and headache.
New intermediate temperature proton conductors : Hydrated heavy alkali thio-hydroxogermanates

Abstract Fuel cells are emerging as popular alternative power sources due to their high efficiencies, low green house gas emissions, and the possibility of using renewable hydrogen fuels. At the heart of the proton-based fuel cell is the proton exchange membrane (PEM) transporting protons from the anode to the cathode while providing electronic insulation. Hydrated polymers such as Nafion® are the most popular PEM for many applications, but they are restricted by strong humidification requirements to operating temperatures below 100 °C. Alternative membrane materials are critically needed for the intermediate temperature range of 100 to 300 °C where higher efficiencies and easier water (steam) management are possible. Here we report a new class of solid inorganic hydroxide proton conductors with mixed anions, specifically hydrated alkali thio-hydroxogermanates. As an example, proton conductivities for the amorphous cesium thio-hydroxogermanate Cs 2 GeS 2 (OH) 2 · x H 2 O (0 x − 3 to 10 − 2 (Ω cm) − 1 for temperatures of 100 to 275 °C under low relative humidities (R.H.
Plasmonic Nanocavity Organic Light‐Emitting Diode with Significantly Enhanced Light Extraction, Contrast, Viewing Angle, Brightness, and Low‐Glare

One central challenge in LEDs is to increase light extraction; but for display applications, other factors may have equal significance, such as ambient-light absorption, contrast, viewing angle, image sharpness, brightness, and low-glare. However, current LED structures enhance only some of the factors, while degrading the others. Here, a new organic LED (OLED) structure is proposed and demonstrated, with a novel plasmonic nanocavity, termed “plasmonic cavity with subwavelength hole-array” (PlaCSH), and exhibits experimentally significant enhancements of all above factors with unprecedented performances. Compared to the conventional OLEDs (the same but without PlaCSH), PlaCSH-OLEDs achieve experimentally: i) 1.57-fold higher external-quantum-efficiency and light-extraction-efficiency (29%/32% without lens, 55%/60% with lens)—among the highest reported; ii) ambient-light absorption not only 2.5-fold higher but also broad-band (400 nm) and nearly angle and polarization independent, leading to lower-glare; iii) fivefold higher contrast (12 000 for 140 lux ambient-light); iv) viewing angle tunable by the cavity length; v) 1.86-fold higher normal-view-brightness; and vi) uniform color over all emission angles. The PlaCSH is an excellent optical antenna—excellent in both radiation and absorption of light. Furthermore, PlaCSH-OLEDs, a simple structure to produce, are fabricated using nanoimprint over large-area (≈1000 cm2), hence scalable to wallpaper size.
Protein Tyrosine Kinase Signaling in the Mouse Oocyte Cortex During Sperm-Egg Interactions and Anaphase Resumption

Fertilization triggers activation of a series of pre-programmed signal transduction pathways in the oocyte that establish a block to polyspermy, induce meiosis resumption, and initiate zygotic development. The fusion between sperm and oocyte results in rapid changes in oocyte intracellular free calcium levels which in turn activate multiple protein kinase cascades in the ooplasm. The present study has examined the possibility that sperm-oocyte interaction involves localized activation of oocyte protein tyrosine kinases which could provide an alternative signaling mechanism triggered by the fertilizing sperm. Confocal immunofluorescence analysis with antibodies to phosphotyrosine and phosphorylated protein tyrosine kinases allowed detection of minute signaling events localized to the site of sperm-oocyte interaction that were not amenable to biochemical analysis. The results provide evidence for localized accumulation of phosphotyrosine at the site of sperm contact, binding, or fusion, which suggests active protein tyrosine kinase signaling prior to and during sperm incorporation. The PYK2 kinase was found to be concentrated and activated at the site of sperm-oocyte interaction and likely participates in this response. Widespread activation of PYK2 and FAK kinases was subsequently observed within the oocyte cortex indicating that sperm incorporation is followed by more global signaling by these kinases during meiosis resumption. The results demonstrate an alternating signaling pathway triggered in mammalian oocytes by sperm contact, binding, or fusion with the oocyte.
Reconstructing Groundwater Source Release Histories Using Hybrid Optimization Approaches

Reconstructing release histories of contaminant sources in groundwater is an important environmental forensics problem for identifying responsible parties and allocating remediation costs in a contamination incident. Such problems typically require the solution of an inverse problem. This paper investigates and compares several hybrid optimization approaches that combine genetic algorithms with a number of local search approaches for solving these problems. Previous studies in this area have focused on simple two-dimensional and/or single-source release history problems. The problems solved in this article address both single- and multiple-source releases in three-dimensional heterogeneous flow fields. A parallel computing environment is used to handle the heavy computational needs of these problems. The results indicate that hybrid optimization methods, especially those that combine an initial global heuristic approach (e.g., genetic algorithms) with a subsequent gradient-based local search approach (e.g...
The rare isotope accelerator project

Only 300 out of thousands of isotopes are stable and exist in nature. The others are unstable and decay within a wide range of lifetimes. The properties of most of these rare isotopes are unknown and can only be inferred, with considerable uncertainty, from theoretical calculations. The proposed Rare Isotope Accelerator (RIA) will make it possible to produce and study more than a thousand new rare isotopes in the laboratory. RIA will be driven by a highly flexible superconducting linear accelerator which will be capable of delivering intense beams of all elements from hydrogen to uranium. The RIA facility will be the most powerful rare isotope research facility in the world.
TRANSIT'S VALUE-ADDED EFFECTS: LIGHT AND COMMUTER RAIL SERVICES AND COMMERCIAL LAND VALUES

Transit-oriented development has gained favor as a means of reducing traffic congestion, promoting affordable housing, and curbing sprawl. The effects of proximity to light and commuter rail stations are modeled as are the effects of freeway interchanges on commercial-retail and office properties in fast-growing Santa Clara County, California. From hedonic price models, substantial capitalization benefits were found, on the order of 23% for a typical commercial parcel near a light rail transit stop and more than 120% for commercial land in a business district and within 0.25 mi of a commuter rail station. Such evidence is of use not only to developers and lenders but also to transit agencies facing lawsuits over purported negative externalities associated with being near rail. It can also help in the design of creative financing, such as value-capture programs.
Reader-Based and Teacher-Centered Instructional Tasks: Writing and Learning About a Short Story in Middle-Track Classrooms.

This study describes how and what 2 classes of middle-track 10th-graders wrote and learned when their teacher employed reader-based and teacher-centered instructional tasks for discussing and writing about a short story. The students wrote an analytic essay in response to the story and completed 3 posttests of story understanding. Retrospective interviews of 4 case-study students were analyzed to examine the students' thinking and reasoning, and to explore their perceptions of the ground rules and teacher expectations as they wrote analytically about the story. The reader-based tasks enabled the students in developing both textual and experiential knowledge about and a thoughtful stance toward the short story. These patterns suggest why the reader-based tasks permitted students to attain significantly higher posttest scores than did the teacher-centered tasks. Reader-based tasks to reading and writing may enable teachers to rethink literature instruction in classrooms with middle-track students.
The Chi Complex and Ambiguities of Meeting

In his article "The Chi Complex and Ambiguities of Meeting" Paul Carter develops a discussion of interpersonal encounters by mobilizing an apparatus of references, ranging from Jean Genet to Levinas, Derrida, Bachmann, Merleau-Ponty, and Arendt. The hypothesis is that meeting another person entails and subsumes a non-meeting; a resistance and a refusal. The article pursues the ambiguity at the heart of encountering the other through an investigation of the urban spaces that are allegedly designed to invite and facilitate meetings. The argument put forward is that these spaces are paradoxically designed to avert encounters. This is especially true in the context of a "new social, economic, and institutional life that seems to call into question the very existence of the collectivities referred to as 'community' or 'society'." The unfolding of this proposition describes a space and a topography that are open, supple, and capable of "mutual transformations." The Greek letter Chi, both in its meaning of chaos and Chora ("a process of cleavage in its double meaning"), is employed as a theoretical example of a place that defies rigidity and closeness and that invites us to linger and pause in order to allow the other to meet and be met.
FORMS: a flexible object recognition and modelling system

We briefly describe a generic statistical framework for representing the shapes of animate objects using principal component analysis and stochastic shape grammars. Such a representation scheme gives a formalism for solving the inverse problem-object recognition. Then we show: how these representations can be extracted from 2D silhouettes by a novel method for skeleton extraction and shape segmentation; how a similarity metric can be defined on this shape space; and how we can perform recognition in a bottom up/top down loop. The system is demonstrated to be stable in the presence of noise, the absence of parts, the presence of additional parts, and considerable variations in articulation and viewpoint. Successful categorization is demonstrated on a dataset of seventeen categories of animate objects. >
Three-dimensional ultrasonography: an objective outcome tool to assess collagen distribution in women with stress urinary incontinence.

Abstract Objectives To examine the distribution of periurethral collagen by three-dimensional ultrasonography (3D US) and to incorporate this technology into a practical treatment decision tree for women with stress urinary incontinence desiring collagen injection. Methods Forty-six women who received periurethral collagen injection were assessed with 3D US to document the position and volume of collagen around the urethra. Patients with a good clinical response were observed with serial 3D US scans. Women with no persistent improvement who showed a low volume or asymmetric distribution of collagen were offered repeat injections. When the patient had no improvement despite symmetric or circumferential distribution of collagen with good volume retention, another anti-incontinence treatment was recommended. Group 1 was composed of women who had a good clinical outcome and group 2 of those who did not. A statistical comparison between the two outcome groups was done to determine whether any particular distribution pattern was associated with an increased likelihood of clinical success. Results Of the 46 patients, 21 (46%) were satisfied with their continence after their last periurethral collagen injection, with a median follow-up of 14.0 months (range 2 months to 4.25 years). A significantly greater proportion of patients in group 1 had circumferentially distributed collagen on 3D US compared with those in group 2 (62% versus 20%, P = 0.006). Conclusions Circumferential distribution of collagen around the urethra is associated with a higher likelihood of clinical success. The assessment of periurethral collagen by 3D US provides an affordable, noninvasive, objective outcome measure that may aid in treatment planning.
Comparability of the MPI and EPI on normal subjects.

The MPI and EPI were compared on two samples of college students consisting of 50 males and 50 females. Form A of the EPI was used. It was found that the MPI and EPI extraversion measures correlated 0.69 for males and 0.74 for females, while the comparable correlations for the neuroticism dimension were 0.70 and 0.71 respectively. Other data are cited supporting a similar degree of comparability of scores between the two measures. No significant relationship was found between E and N in either of the samples or with either the MPI or EPI.
Coronary Artery Abnormalities in Hyper-IgE Syndrome

Hyper-IgE syndrome (HIES) is a rare primary immunodeficiency caused by autosomal dominant STAT3 mutations resulting in recurrent infections and connective tissue abnormalities. Coronary artery abnormalities have been reported infrequently. We aimed to determine the frequency and characteristics of coronary artery abnormalities. STAT3-mutated HIES patients (n = 38), ranging in age from 8 to 57 years, underwent coronary artery imaging by computed tomography or magnetic resonance imaging. Images were evaluated for tortuosity, dilation, and aneurysm. Charts were reviewed for cardiac risk factors. To allow blinded image interpretation, an age- and gender-matched non-HIES group was also evaluated (n = 33). Coronary artery tortuosity or dilation occurred in 70% of HIES patients, with aneurysms present in 37%, incidences much higher than in the literature and in our non-HIES group, in which 21% had tortuosity or dilation and 3% had aneurysms. Hypertension was more common in the HIES group than in the general population and was associated with vessel abnormalities. Atherosclerosis was uncommon and mild. Coronary artery aneurysms and tortuosity are common in HIES, despite a paucity of atherosclerosis, suggesting that STAT3 plays an integral role in human vascular remodeling and atherosclerosis.
Structural Investigation of Rimantadine Inhibition of the AM2-BM2 Chimera Channel of Influenza Viruses

The M2 channel of influenza A is a target of the adamantane family antiviral drugs. Two different drug-binding sites have been reported: one inside the pore, and the other is a lipid-facing pocket. A previous study showed that a chimera of M2 variants from influenza A and B that contains only the pore-binding site is sensitive to amantadine inhibition, suggesting that the primary site of inhibition is inside the pore. To obtain atomic details of channel-drug interaction, we determined the structures of the chimeric channel with and without rimantadine. Inside the channel and near the N-terminal end, methyl groups of Val27 and Ala30 from four subunits form a hydrophobic pocket around the adamantane, and the drug amino group appears to be in polar contact with the backbone oxygen of Ala30. The structures also reveal differences between the drug-bound and -unbound states of the channel that can explain drug resistance.
Crosslinking studies on the organization of the 16 S ribosomal RNA within the 30 S Escherichia coli ribosomal subunit

Abstract The location and frequency of RNA crosslinks induced by photoreaction of hydroxymethyltrimethylpsoralen with 30 S Escherichia coli ribosomal subunits have been determined by electron microscopy. At least seven distinct crosslinks between regions distant in the 16 S rRNA primary structure are seen in the inactive conformation of the 30 S particle. All correspond to crosslinked features seen when the free 16 S rRNA is treated with hydroxymethyltrimethylpsoralen. The most frequently observed crosslink occurs between residues near one end of the molecule and residues about 600 nucleotides away to generate a loop of 570 bases. The size and orientation of this feature indicate it corresponds to the crosslinked feature located at the 3′ end of free 16 S rRNA. When active 30 S particles are crosslinked in 5 m m -Mg 2+ , six of the seven features seen in the inactive 30 S particle can still be detected. However, the frequency of several of the features, and particularly the 570-base loop feature, is dramatically decreased. This suggests that the long-range contacts that lead to these crosslinks are either absent or inaccessible in the active conformation. Crosslinking results in some loss of functional activities of the 30 S particle. This is consistent with the notion that the presence of the crosslink that generates the 570-base loop traps the subunit in an inactive form, which cannot associate with 50 S particles. The arrangement of the interacting regions crosslinked by hydroxymethyltrimethylpsoralen suggests that the RNA may be organized into three general domains. A striking feature of the Crosslinking pattern is that three of the seven products involve regions near the 3′ end of the 16 S rRNA. These serve to tie together large sections of rRNA. Thus structural changes at the 3′ end could, in principle, be felt through the entire 30 S particle.
Learning to Teach Culturally Diverse Learners: Charting Change in Preservice Teachers' Thinking about Effective Teaching

We explored the use of 2 measurement strategies-concept maps and surveys-to assess the effects of a multicultural education course on the cognitions of individuals and groups of preservice teachers. Participants included 17 preservice teachers enrolled in a 5-week multicultural education course required as part of a 1-year M.Ed. and credential program at a public university. Data were gathered before and after the course to assess preservice teachers' beliefs and conceptual changes in their representations of effective teaching for culturally diverse learners. Results suggested that 2 groups of students began the course with distinct beliefs and conceptualizations in this area, as indicated by differences in the density of their concept maps. Results also suggested that multiple indicators of cognitive change must be used to better understand the effect of these courses on preservice teachers' cognitions. Group B students had lower-density maps prior to the course than after the course. Specifically, alth...
Self-complementary AAV mediates gene targeting and enhances endonuclease delivery for double-strand break repair

Adeno-associated virus (AAV) mediates gene targeting in humans by providing exogenous DNA for allelic replacement through homologous recombination. In comparison to other methods of DNA delivery or alternative DNA substrates, AAV gene targeting is reported to be very efficient, perhaps due to its single-stranded DNA genome, the inverted terminal repeats (ITRs), and/or the consequence of induced cellular signals on infection or uncoating. These viral attributes were investigated in the presence and absence of an I-Sce endonuclease-induced double-strand break (DSB) within a chromosomal defective reporter in human embryonic kidney cells. Gene correction was evaluated using self-complementary (sc) AAV, which forms a duplexed DNA molecule and results in earlier and robust transgene expression compared with conventional single-strand (ss) AAV genomes. An scAAV repair substrate was modestly enhanced for reporter correction showing no dependency on ssAAV genomes for this process. The AAV ITR sequences were also investigated in a plasmid repair context. No correction was noted in the absence of a DSB, however, a modest inhibitory effect correlated with the increasing presence of ITR sequences. Similarly, signaling cascades stimulated upon recombinant AAV transduction had no effect on plasmid-mediated DSB repair. Noteworthy, was the 20-fold additional enhancement in reporter correction using scAAV vectors, over ss versions, to deliver both the repair substrate and the endonuclease. In this case, homologous recombination repaired the defective reporter in 4% of cells without any selection. This report provides novel insights regarding the recombination substrates used by AAV vectors in promoting homologous recombination and points to the initial steps in vector optimization that could facilitate their use in gene correction of genetic disorders.
Differential response of barley varieties to Fe stress

Abstract Previous studies indicated that plant genotypes which tolerate acid soils may be susceptible to Fe stress when grown at high pH. Evidence of this relationship was obtained through comparisons of species adapted to strongly acid or alkaline soil environments and of plant populations within species which differ widely in acid or alkaline soil tolerance. Such a correlation between Fe inefficiency and tolerance to excess Al has not been shown for barley (Hordeum vulgare L.). The purpose of the present investigation was to determine whether barley varieties, representing a range of Al tolerance, also respond differently to Fe stress. Al‐tolerant ‘Dayton’ and Al‐sensitive ‘Kearney’ barley were grown in nutrient solutions containing Fe concentrations ranging from 0.025 to 2.0 ppm, as FeEDDHA, at an initial pH of 6.5. Kearney was more resistant to Fe deficiency than Dayton and maintained more normal growth at the lower Fe levels. In addition, this variety established a lower pH in the root zone and a hig...
IFEC 2013 Breaks Records for Participation: A Summary of the Competition Results

The 2013 IEEE International Future Energy Challenge (IFEC) broke the record for participation, with a total of 36 teams submitting proposals for two topics, Topic A and Topic B. Topic A, "Highly Efficient Grid-Tied Microinverter for Photovoltaic Panels Using Wide Bandgap Devices," was held at Ohio State University, Columbus, United States. Topic B, "Low Power Off-Line Light-Emitting Diode (LED) Driver with Long Lifetime," was held at Zhejiang University (ZJU) in Hangzhou, Zhejiang, a southeast province of China. The final events for both topics were successfully completed at the end of July 2013.
Observations of ionospheric convection from the Wallops SuperDARN radar at middle latitudes

[1] During geomagnetic storms the ability of the Super Dual Auroral Radar Network (SuperDARN) to measure ionospheric convection becomes limited when the radars suffer from absorption and the auroral disturbance expands equatorward of the radar sites. To overcome these shortcomings, it was decided to construct a SuperDARN radar at middle latitudes on the grounds of the NASA Wallops Flight Facility. This paper presents the first comprehensive analysis of Doppler measurements from the Wallops radar, which commenced operations in May 2005. Wallops measurements are compared with the Goose Bay radar during the onset of a geomagnetic storm on 31 August 2005: Goose Bay measured the onset of geomagnetic activity at high latitude while Wallops monitored the expansion of convection to middle latitudes. Average convection patterns binned by the Kp geomagnetic index are also presented. During weak-moderate geomagnetic activity (Kp ≤ 3) the Wallops radar observes ionospheric irregularities between 50° and 60° magnetic latitude drifting westward across much of the nightside. When these measurements are incorporated into the calculation of an average SuperDARN convection pattern, the streamlines of polar cap outflow on the nightside become kinked in a manner reminiscent of the Harang discontinuity. This morphology arises quite naturally when the two-cell convection at high latitudes merges with the prevailing westward convection at middle latitudes. During increased geomagnetic activity (Kp ≥ 3), Wallops is able to measure the expansion of auroral electric fields to middle latitudes and the average SuperDARN cross-polar cap potential is increased by 25%.
Miocene volcanism and deformation in the western Cordillera and high plateaus of south-central Peru

New radiometric ages on tuffs from south-central Peru support the postulated flare-up of volcanic activity during early Miocene time. In the region of Huancavelica, Julcani, and Lircay, lower Miocene rocks lie on folded strata of pre-Cenozoic age; the absence of units of Eocene and early Oligocene age indicates that this area remained positive after Incaic deformation in Eocene time. Conglomerate beds reflecting erosion attendant on the first pulse of late Cenozoic (Quechuan) compressive deformation do not appear in the stratigraphic record until after 21.5 m.y. B.P. In one section, beds of coarse conglomerate are underlain by tuff dated at 18.3 ± 0.6 m.y. and overlain by tuff dated at 17.3 ± 0.2 m.y. At another locality, beds of conglomerate conformably overlie tuff dated at 19.6 ± 0.8 m.y. If we incorporate published data from other areas in central and southern Peru, it appears that Quechuan deformation began in early Miocene time between 19.5 and 17 m.y. ago. A firm age for the end of the first pulse of Quechuan deformation in this region is provided by an ash-flow sheet dated at 12 to 12.5 m.y. that unconformably overlies strata of Eocene to early Miocene age.
31P NMR peak width in humate–phosphate complexes

Abstract The mobility of inorganic phosphate (P) attached to solid humic acid (HA) and fulvic acid (FA) via a metal “anchor” was investigated by 31 P NMR spectroscopy. The peak width of the 31 P resonance was monitored as an indicator of the degree of attachment of the element to the humic matrix. The concept was demonstrated by contrasting peak widths of thoroughly dry M–HA–P complexes with those that had been allowed to absorb different amounts of moisture. It was shown that the presence of moisture, which enhances the mobility of P, results in a significant reduction of chemical shift peak width. The work was extended to comparisons between dry systems with and without metal anchors; systems with anchors consisting of different metals; systems comprising different humates and fulvates; and systems with different size fractions of a humate. It was shown that both the type of humate/fulvate, and the metal anchor used lead to different degrees of mobility within the humic matrix. It was also found that the effect of metal addition on 31 P peak width is greater with fulvates and smaller HA fractions than with the larger HA components.
Performance of a rail car equipped with independently rotating wheelsets having yaw control

AbstractRail vehicles experience problems of hunting and severe wheel/rail wear which result in lower critical speeds. The design of the conventional railway wheelset, consisting of two wheels mounted rigidly on an axle, is one of the main factors inhibiting high-speed operation of rail vehicles. In this paper the potential for good dynamic stability at high speeds and improved ride comfort in a rail vehicle equipped with an independently rotating wheelset (IRW) having yaw control are examined. The control for the yaw rotation is provided by a state-variable feedback controller.
The biologic activity of polyanions: Past history and new prospectives

The toxicology of synthetic polyanions relates to molecular weight. This developed from experience with pyran copolymer (divinyl ether maleic anhydride copolymer), which was tested clinically as an antitumor agent and found to be too toxic for continued clinical trial. Synthetic polyanions of low molecular weight are potent stimuli to macrophage phagocytic function and possess antitumor activity. Increased host resistance to pathogens including bacteria, fungi, viruses, and trypanosomes is seen. In contrast to lower-molecular-weight fractions, higher-molecular-weight samples inhibit macrophage function, and apparently increased molecular weight > 15,000 is necessary for antiviral and immunologic stimulating capacity. One possible mechanism for the action of polyanions may relate to redistribution of calcium ions within the cell and increasing cyclic GMP activity. This is a redefinition for the role of polyanions in sol–gel alteration in cytoplasm. The killing effect of the polyanion-activated macrophage on tumor cells resembles that of the polyanion on the nucleus. Polyanions may be potent controllers of the stability of DNA within the nucleus and can act to derepress cells to turn on protein synthesis or, alternatively, inhibit enzymes involved in virus synthesis and control of RNA or DNA polymerase. Thus, they are cogent tools in an understanding of the physiology of nuclear interaction. Biological use for these agents can be developed not only in clinical approaches to inhibition of tumor or viral infection, but to eliminate plutonium, and provide selective enzyme inhibition and protein interaction which allows for isolation, neutralization, and characterization of blood and tissue protein and glycoprotein fractions vital for a wide range of pathophysiology.
Clifford Algebra Exponentials and Planar Linkage Synthesis Equations

This paper uses the exponential defined on a Clifford algebra of planar projective space to show that the standard-form design equations used for planar linkage synthesis are obtained directly from the relative kinematics equations of the chain. The relative kinematics equations of a serial chain appear in the matrix exponential formulation of the kinematics equations for a robot. We show that formulating these same equations using a Clifford algebra yields design equations that include the joint variables in a way that is convenient for algebraic manipulation. The result is a single formulation that yields the design equations for planar 2R dyads, 3R triads, and nR single degree-of-freedom coupled serial chains and facilitates the algebraic solution of these equations including the inverse kinematics of the chain. These results link the basic equations of planar linkage design to standard techniques in robotics.
Cooperative Stepwise Relaying and Combining for Multihop Vehicular Wireless Communication

Vehicular ad hoc networks (VANETs) require cooperation among vehicles in exchanging information, which improves traffic efficiency and safety. Cooperative communication among these vehicles can significantly improve wireless communication performance. This paper proposes a novel cooperative scheme named cooperative stepwise relaying and combining (CSRC) for multihop VANETs, which utilizes low-order demodulations to partially demodulate high-order modulated signals cooperatively at intermediate relay vehicular nodes. Bit error rate (BER) probability is analyzed. The performance comparison among the proposed CSRC and conventional cooperative schemes is conducted through simulation and a software-defined radio testbed. The experiment results show that CSRC significantly improves the multihop VANETs' performance with cooperative communication.
Dual collimation acquisition for high resolution, low noise SPECT

Dual-collimation (DC) imaging for single photon emission computed tomography (SPECT) is presented as a technique to improve effective sensitivity with little loss of resolution. For some imaging tasks, DC can overcome the inherent tradeoff between resolution and sensitivity of gamma camera collimators. Simulations were used to investigate the system performance without the expense of collimator fabrication. With DC for SPECT, a single image which is consistent with two projection sets acquired in two different collimators is reconstructed, one with high resolution/low sensitivity and another with high sensitivity/low resolution. By incorporating a detailed model of the SPECT acquisition geometry (including each collimator) into the maximum-likelihood expectation maximization reconstruction algorithm, an image having a combination of moderate noise and moderate resolution is produced. Based on a preliminary evaluation of DC for SPECT, it is concluded that, for moderate-size (2-cm radius) cold lesion imaging, DC can provide significant improvement in contrast-to-noise without significantly sacrificing image contrast, although for smaller lesions this advantage is diminished. For small hot spot imaging, DC can provide significant improvement in image noise without significantly sacrificing image resolution. >
Intake and Performance of Lactating Cows Grazing Diverse Forage Mixtures

Twenty multiparous Holstein cows in midlactation grazed pastures of 4 forage mixtures in a 12-wk study repeated during 2 grazing seasons to determine if forage mixture complexity affected intake and productivity of lactating dairy cows. The forage mixtures were 1) orchardgrass plus white clover [2 species (SP)]; 2) orchardgrass, white clover, and chicory (3SP); 3) orchardgrass, tall fescue, perennial ryegrass, red clover, birdsfoot trefoil, and chicory (6SP); and 4) 6SP mixture plus white clover, alfalfa, and Kentucky bluegrass (9SP). Total herbage intake was similar among forage mixtures, averaging 12.0 kg/d across all forage mixtures and years. Milk production and composition were not affected by forage mixture or year, and averaged 34.6 kg/d, 3.4%, and 2.8% for milk production, milk fat percentage, and milk protein percentage, respectively. The conjugated linoleic acid content of milk fat was higher for cows that grazed the 3SP, 6SP, and 9SP mixtures than from cows that grazed the 2SP mixture (1.02 vs. 0.87 g of conjugated linoleic acid/100 g of fatty acids, respectively). Blood glucose, blood urea nitrogen, and nonesterified fatty acids were not affected by forage mixture and averaged 69.2 mg/dL, 13.4 mg/dL, and 277.5 μEq/L, respectively. The results of this study indicate that altering the forage mixture in pastures did not affect dry matter intake, milk production, or blood metabolite profiles of lactating cows. The use of complex mixtures of forages in grazing systems should not affect dairy cow performance.
Deglacial changes in dust flux in the eastern equatorial Pacific

Abstract Atmospheric dust levels may play important roles in feedbacks linking continental source areas, tropical convection, marine productivity, and global climate. These feedbacks appear to be particularly significant in the tropical Pacific, where variations in local convection and productivity have been demonstrated to have impacts on climate at higher latitudes. Modeling of past dust levels and related feedbacks has been limited, however, by a paucity of observational data. In this study we present a temporal and spatial survey of dust fluxes to the eastern equatorial Pacific over the past 30 kyr. Glacial and Holocene fluxes of 232Th, a proxy for continental material, were calculated by normalization to 230Th from a north–south transect of cores along 110°W between 3°S and 7°N (ODP sites 848–853). Fluxes were 30–100% higher during the last glacial, suggesting increased dustiness in both hemispheres during the glacial period. In both time periods, dust fluxes decrease towards the south, reflecting scavenging of Northern Hemisphere dust by precipitation at the ITCZ. The Holocene meridional dust flux gradient between 7°N and 3°S is characterized by a steep drop in dust levels at the southern edge of the modern range of the ITCZ, while the gradient is shallower and more nearly linear during the last glacial. This change may indicate that the glacial ITCZ in this region was a less effective barrier to inter-hemispheric dust transport, most likely due to a decrease in convective intensity and precipitation during the last glacial; alternatively, the change in gradient may be explained by increased variability in the location of the glacial ITCZ. Our data do not appear to require a mean southerly displacement of the glacial ITCZ, as suggested by the results of other studies.
Identification of Feigned Mental Retardation Using the New Generation of Malingering Detection Instruments: Preliminary Findings

A recent Supreme Court decision—Atkins v. Virginia, 536 U.S. 304 (2002)—prohibiting the execution of mentally retarded (MR) defendants may have raised the attractiveness of feigning this condition in the criminal justice system. Unfortunately, very few published studies have addressed the detection of feigned MR. The present report compared results from tests of intelligence, psychiatric feigning, and neurocognitive faking in a group of 26 mild MR participants (MR) and 25 demographically matched community volunteers asked to feign MR (CVM). Results showed that the CVM suppressed their IQ scores to approximate closely the level of MR participants. WAIS-III and psychiatric malingering measures were relatively ineffective at discriminating feigned from genuine MR. Although neurocognitive malingering tests were more accurate, their reduced specificity in MR participants was of potential concern. Revised cutting scores, set to maintain a Specificity rate of about .95 in MR clients, were identified, although th...
Tax-Deferred Accounts, Constrained Choice and Estimation of Individual Saving

The paper analyzes the effect of tax-deferred individual retirement accounts (IRAs) in the United States on net individual saving. The results are based on a model of constrained optimization with the limit on tax-deferred saving the principle constraint. The estimates suggest that contributions to IRAs represent substantial net saving increases. Were the IRA limit to be increased, only about 10 to 20% of resulting increase in IRA contributions would be taken from other savings. About 50% would come from reduced consumption and about 35% from reduced
Magnetic phase contrast X-ray microscopy

This paper reports the use of phase sensitive X-ray optical elements in the soft X-ray transmission microscope beamline to image the magnetic domain structure of Gd25Fe75 amorphous layer at high spatial resolution. The amorphous magnetic material is deposited by electron beam evaporation onto a polyimid substrate exhibiting a pronounced perpendicular magnetic anisotropy. Observations show a magnetic contrast at the boundary of the magnetic domains; i.e. at the domain walls where the magnetization changes its direction. Hence, the availability of the X-ray optical elements adds an important new contrast mechanism to magnetic X-ray microscopy.
Coinfection with HIV and Hepatitis C Virus in Injection Drug Users and Minority Populations

Coinfection with human immunodeficiency virus (HIV) and hepatitis C virus (HCV) is common. In the United States, it has been estimated that 25% of persons infected with HIV are also infected with HCV. The prevalence of coinfection with HIV and HCV is highest among those infected via percutaneous routes. In fact, in urban areas in the United States, 50%-90% of persons infected with HIV via injection drug use are coinfected with HCV. In addition, limited data from drug treatment centers in these urban areas suggest that the prevalence of coinfection with HIV and HCV may be highest among African Americans and Hispanics. Little information is available with regard to the epidemiology of coinfection with HIV and HCV among injection drug users (IDUs) or minority populations. Likewise, although there is a growing body of data on the potential complexities of treating HCV among IDUs and the poor response to current anti-HCV treatment among African Americans, few data address the therapy of coinfection with HIV and HCV among IDUs and minority populations.
Virtual prepaid tokens for Wi-Fi hotspot access

We introduce virtual prepaid tokens (VPT), a novel billing scheme that allows users to obtain access at Wi-Fi hotspots without having an account with a hotspot provider or a physical prepaid token (PPT). Upon arrival at a hotspot, a user buys a VPT online, using a third-party payment server with which the user already has an account. Experiments show that users can buy a VPT and gain full Internet connectivity in less than 15 seconds, i.e. much less time than it would take to create another account or to buy and activate a PPT. VPT can be used in hotspots that use a captive portal or IEEE 802.1x for user authentication. The latter alternative enables better security. We also contribute a novel technique that allows a single access point to authenticate users by either method. Hotspots can use this solution for migrating to 802.1x without disrupting legacy captive-portal users. Experiments demonstrate that the proposed technique has little overhead and interoperates broadly.