cssi/SciSciGPT-SciSciNet huggingface dataset:
Longevity of granular iron in groundwater treatment processes: changes in solute transport properties over time.

Abstract Although progress has been made toward understanding the surface chemistry of granular iron and the mechanisms through which it attenuates groundwater contaminants, potential long-term changes in the solute transport properties of granular iron media have until now received relatively little attention. As part of column investigations of alterations in the reactivity of granular iron, studies using tritiated water ( 3 H 2 O) as a conservative and non-partitioning tracer were periodically conducted to independently isolate transport-related effects on performance from those more directly related to surface reactivity. Hydraulic residence time distributions (HRTDs) within each of six 39-cm columns exposed to bicarbonate solutions were obtained over the course of 1100 days of operation. First moment analyses of the data revealed generally modest increases in mean pore water velocity ( v ) over time, indicative of decreasing water-filled porosity. Gravimetric measurements provided independent estimates of water-filled porosity that were initially consistent with those obtained from 3 H 2 O tracer tests, although at later times, porosities derived from gravimetric measurements deviated from the tracer test results owing to mineral precipitation. The combination of gravimetric measurements and 3 H 2 O tracer studies furnished estimates of precipitated mineral mass; depending on the assumed identity of the predominant mineral phase(s), the porosity decrease associated with solute precipitation amounted to 6–24% of the initial porosity. The accumulation of mineral and gas phases led to the formation of regions of immobile water and increased spreading of the tracer pulse. Application of a dual-region transport model to the 3 H 2 O breakthrough curves revealed that the immobile water-filled region increased from initially negligible values to amounts ranging between 3% and 14% of the total porosity in later periods of operation. For the aged columns, mobile–immobile mass transfer coefficients ( k mt ) were generally in the range of 0.1–1.0 day −1 and reflected a slow exchange of 3 H 2 O between the two regions. Additional model calculations incorporating sorption and reaction suggest that although changes in HRTD can have an appreciable effect on trichloroethylene (TCE) transformation, the effect is likely to be minor relative to that stemming from passivation of the granular iron surface.
Anomere Benzoesäureester des Galaktosamins

Die Anomeren des 1.3.4.6-Tetra-O-benzoyl-N-benzoyl-D-galaktosamins und des 1.3.4.6-Tetra-O-benzoyl-N-Cbo-D-galaktosamins wurden durch stereospezifische Methoden hergestellt. Die Trennung der mittels unspezifischer Benzoylierungen erhaltenen Anomerengemische gelang sowohl durch Kristallisation als auch durch Chromatographie. Sechs Alkyl-3.4.6-tri-O-benzoyl-β-D-galaktosaminid-hydrobromide werden beschrieben.
Pancreastatin: characterization of biological activity.

Summary Pancreastatin (PST) (1–49) was first isolated from the porcine pancreas and can inhibit glucose-induced insulin release. PST (33–49), a PST C-terminal fragment, can also inhibit insulin release. The purpose of this study was to determine the shortest C-terminal biologically active fragment of PST, in terms of inhibition of insulin release from the isolated perfused rat pancreas. Porcine PST (1–49) and C-terminal fragments, PST (33–49), PST (35–49), PST (37–49) and PST (39–49) were synthesized by solid-phase methodology. PST (1–49), PST (33–49) and PST (35–49), at 10 nM, significantly (p
Young adults with acute lymphoblastic leukemia treated with a pediatric-inspired regimen do not need a bone marrow transplant in first remission

To the editor: Gupta et al[1][1] concluded that young adult patients with acute lymphoblastic leukemia (ALL) aged 15 to 35 years should be treated in first remission with allogeneic transplant. They based their judgment on a meta-analysis of 13 studies, each of which had a control regimen used
Teachers’ reports of learning and application to pedagogy based on engagement in collaborative peer video analysis

Given international use of video-based reflective discussions in teacher education, and the limited knowledge about whether teachers apply learning from these discussions, we explored teachers’ learning of new ideas about pedagogy and their self-reported application of this learning. Nine inservice and 48 preservice teachers participated in video-based reflective discussions and documented their learning, sources of knowledge that contributed to their learning, and application of this learning to their teaching in their practica courses. A total of 227 response sheets with this information were collected. Multilevel logit regression was used to examine how sources of learning and content learned were related to teachers’ application of learning to their teaching practices. We found that teachers reported applying 40% of their learning; particularly, what they learned about methods and materials for instruction, and that they learned from both video and discussion almost equally.
Humors from Tumors: Carcinoembryonic Antigen, Alpha-Fetoprotein, and Digestive System Cancer

Excerpt There is a growing list of tumor-associated fetal substances that show diagnostic promise and may in time have immunotherapeutic and prophylactic value (1, 2). Malignancies of the digestive...
Hybrid regions for post-change mean in a sequence of normal variables

The hybrid bootstrap uses resampling ideas to extend the duality approach to the interval estimation for a parameter of interest when there are nuisance parameters. The confidence region constructed by the hybrid bootstrap may perform much better than the ordinary bootstrap region in a situation where the data provide substantial information about the nuisance parameter, but limited information about the parameter of interest. We apply this method to estimate the post-change mean after a change is detected by a stopping procedure in a sequence of independent normal variables. Since distribution theory in change point problems is generally a challenge, we use bootstrap simulation to find empirical distributions of test statistics and calculate critical thresholds. Both likelihood ratio and Bayesian test statistics are considered to set confidence regions for post-change means in the normal model. In the simulation studies, the performance of hybrid regions are compared with that of ordinary bootstrap regio...
Probing the frontostriatal loops involved in executive and limbic processing via interleaved TMS and functional MRI at two prefrontal locations: a pilot study.

Background The prefrontal cortex (PFC) is an anatomically and functionally heterogeneous area which influences cognitive and limbic processing through connectivity to subcortical targets. As proposed by Alexander et al. (1986) the lateral and medial aspects of the PFC project to distinct areas of the striatum in parallel but functionally distinct circuits. The purpose of this preliminary study was to determine if we could differentially and consistently activate these lateral and medial cortical-subcortical circuits involved in executive and limbic processing though interleaved transcranial magnetic stimulation (TMS) in the MR environment.
Imaging optics for low-loss high-resolution silica image fiber

Recently, a long low-loss silica image fiber was developed by a new fabrication technology. A large number of pixel fibers, corresponding to the pixels of the final product, are bundled, collapsed by heating, and drawn into an image fiber unit, which is a single rather thick image-guiding glass fiber with multiple discrete pixels. Although an image fiber with ~104 pixels, which is comparable with conventional fiber endoscopes, has already been produced by this new fabrication technology, increasing the number of pixels—more than 105—is required to develop.
Propagation of surface waves and waveguide modes guided by a dielectric slab inserted in a sculptured nematic thin film

Wave propagation guided by a dielectric slab inserted in a sculptured nematic thin film (SNTF) was studied theoretically. Two types of guided waves can be identified: (i) surface (Dyakonov--Tamm) waves guided by one or both of the two planar interfaces of the dielectric slab and the SNTF, and (ii) waveguide modes in the dielectric waveguide formed by the slab with the SNTF as the cladding. As the thickness of the dielectric slab is increased, the number of waveguide modes increases. If the slab thickness is less than twice the e-folding distance into the dielectric slab, the Dyakonov--Tamm waves propagate coupled to both interfaces; the coupling decreases and eventually vanishes as the slab thickness increases, so that Dyakonov--Tamm waves are guided by the individual dielectric-SNTF interfaces independently. The chosen structure supports the propagation of Dyakonov--Tamm waves in all directions, in contrast to the restricted range of propagation supported by a single SNTF-dielectric interface. Propagation of both Dyakonov--Tamm waves and waveguide modes should occur in practice with negligible attenuation, in contrast to that of surface-plasmon-polariton waves that are guided when the dielectric slab is replaced by a metal slab.
A finite element formulation to solve a non-local constitutive model with stresses and strains due to slip gradients

Solving constitutive models that incorporate the effects of plasticity and slip gradients is often complicated by the non-local nature of the models. This work presents a finite element solution to a crystal plasticity constitutive model that includes kinematic and stress effects due to slip gradients. The foundation of the model is a three term multiplicative decomposition of the deformation gradient that results in a second order differential equation in terms of the stress that drives slip. Converting the equation into a weak form results in an integral equation that includes first order derivatives of the stress as well as boundary conditions for the stress and gradients of slip rate for each slip system. Using this weak form, an incremental finite element method is developed to solve the constitutive model within a finite element solution to the equilibrium equation. Results for the compression of a two-dimensional plate show the effects of including slip gradient effects in the constitutive model and indicate the tendency for localization of the slip and dislocation density into narrow bands separating regions of nearly constant dislocation density and long range strain.
Improving literacy in women and girls globally.

In May 2006 I had the opportunity to deliver boxes of childrens books from our family and a nonprofit organization "Shared Books: Kid to Kid" to an orphanage in the rural community of Gatchina in the Russian Federation. Beautiful curly haired blonde little 4-year-old Natalia sat on the floor and hugged the book close to her heart. The joy in the faces of the children who received these books was heartwarming; thus this column focuses on literacy in women and children globally. Many of the worlds women and children have little access to written works and are either marginally literate or illiterate. Literacy is defined as "using printed and written information to function in society to achieve ones goals and to develop ones knowledge and potential" (National Center for Education Statistics 2006). It is estimated that 781 million adults worldwide are illiterate most of whom are women. Globally 140 million children are not attending school with more than 50% of them being girls (UNESCO 2006). When I had the opportunity to conduct research in Guatemala most indigenous children not attending school past the second or third grade level were girls. They either sold goods in the marketplace or were kept at home to care for younger siblings so their mothers could be employed outside the home. Their brothers remained in school. In other countries cultural beliefs keep girls out of school as does concern about violence against girls and women. (excerpt)
Reconciling resource utilization and resource selection functions.

Summary 1. Analyses based on utilization distributions (UDs) have been ubiquitous in animal space use studies, largely because they are computationally straightforward and relatively easy to employ. Conventional applications of resource utilization functions (RUFs) suggest that estimates of UDs can be used as response variables in a regression involving spatial covariates of interest. 2. It has been claimed that contemporary implementations of RUFs can yield inference about resource selection, although to our knowledge, an explicit connection has not been described. 3. We explore the relationships between RUFs and resource selection functions from a hueristic and simulation perspective. We investigate several sources of potential bias in the estimation of resource selection coefficients using RUFs (e.g. the spatial covariance modelling that is often used in RUF analyses). 4. Our findings illustrate that RUFs can, in fact, serve as approximations to RSFs and are capable of providing inference about resource selection, but only with some modification and under specific circumstances. 5. Using real telemetry data as an example, we provide guidance on which methods for estimating resource selection may be more appropriate and in which situations. In general, if telemetry data are assumed to arise as a point process, then RSF methods may be preferable to RUFs; however, modified RUFs may provide less biased parameter estimates when the data are subject to location error.
Low-Risk Patients With Chest Pain in the Emergency Department: Negative 64-MDCT Coronary Angiography May Reduce Length of Stay and Hospital Charges

OBJECTIVE. The current standard-of-care workup of low-risk patients with chest pain in an emergency department takes 12-36 hours and is expensive. We hypothesized that negative 64-MDCT coronary angiography early in the workup of such patients may enable a shorter length of stay and reduce charges.MATERIALS AND METHODS. The standard-of-care evaluation consisted of serial cardiac enzyme tests, ECGs, and stress testing. After informed consent, we added cardiac CT early in the standard-of-care workup of 53 consecutive patients. Fifty patients had negative CT findings and were included in this series. The length of stay and charges were analyzed using actual patient data for all patients in the standard-of-care workup and for two earlier discharge scenarios based on negative cardiac CT results: First, CT plus serial enzyme tests and ECGs during an observation period followed by discharge if all were negative; and second, CT plus one set of enzyme tests and one ECG followed by discharge if all were negative. Co...
New wrinkles in old receptors: Core fucosylation is yet another target to inhibit TGF-β signaling

Shen et al. exploit glycobiology to dampen transforming growth factor-β (TGF-β) signaling and ameliorate renal fibrosis after ureteral obstruction. Core fucosylation of N-linked oligosaccharides in TGF-β receptors is required for receptor function. Adenoviruses expressing Fut8-fucosyl transferase-shRNA inhibited receptor fucosylation, decreased tubule TGF-β signaling, and reduced fibrosis. Fut8-shRNA interferes with core fucosylation of other receptors also. Regardless, this first attempt to capitalize on a new aspect of TGF-β receptor function provides a basis for further research.
Fluids and shear zones in the deep crust

Abstract The continental deep crust is normally nearly fluid-absent. During and after active tectonism (extension, thrusting or shearing), fluids may be abundant in the deep crust and may be associated with such diverse phenomena as granulite-facies metamorphism, shear zone alkaline granites, carbonatite-lamprophyre-syenite complexes, and various kinds of metasomatism, including region carbonatization, fenitization, granitization, and, probably, extreme large-ion lithophile element depletion. The fluids are H2O-CO2 mixtures with variable halogens, alkalis and dissolved silicate constituents. CO2-rich fluids are inferred from dense carbonic inclusions in some deep-crustal granulites, both volcanic ejecta and uplifted deep-crustal terrains. CO2-H2O-dominated fluids must be fairly oxidizing, and may account for upward transport of Au, Sb, As and S from the lower crust and upper mantle, with enrichment of these elements at shallow levels. Crustal sources of abundant CO2 are not likely, either from meteoric sources or from buried carbonates because of their refractory nature. The most plausible source is asthenospheric carbonatite, kimberlite, and alkali basalt liquids, and volatile-enriched lithosphere. Exsolution of fluids of varying CO2/H2O ratios is possible upon freezing of the magmas, depending on depth of magma generation, velocity of ascent and degree of volatile presaturation of the lithosphere. The enriched lithosphere in areas of deep-seated magmatism is an intermediate storage site for CO2 and H2O. Melts and fluids are liberated from the mantle under tensional conditions, which can include lithospheric strike-slip faulting (transtension) and even localized tension generated in convergence. The fluids can transport heat upward, which augments their ability to metasomatize and melt the lower crust. Melting of the crust can occur under high-CO2 fluids at granulite facies conditions to produce syenitic magmas, and this could conceivably be accomplished by action of mantle-derived fluids without the need for large-scale basaltic underplating of the crust. The possibility of crust-mantle interactions is much greater if mantle-derived fluids permeate the lower crust; effects on isotopes and trace elements may be substantial in zones of enhanced permeability like the Nordre Stromfjord shear of Greenland and comparable megashears.
A Model for the Universe that Begins to Resemble a Quantum Computer

This article presents a sequential growth model for the Universe that acts like a quantum computer. The basic constituents of the model are a special type of causal set (causet) called a c-causet. A c-causet is defined to be a causet that has a unique labeling. We characterize c-causets as those causets that form a multipartite graph or equivalently those causets whose elements are comparable whenever their heights are different. We show that a c-causet has precisely two c-causet offspring. It follows that there are 2n c-causets of cardinality n + 1. This enables us to classify c-causets of cardinality n + 1 in terms of n-bits. We then quantize the model by introducing a quantum sequential growth process. This is accomplished by replacing the n-bits by n-qubits and defining transition amplitudes for the growth transitions. We mainly consider two types of processes, called stationary and completely stationary. We show that for stationary processes, the probability operators are tensor products of positive rank-one qubit operators. Moreover, the converse of this result holds. Simplifications occur for completely stationary processes. We close with examples of precluded events.
CHARGE-COUPLED DEVICES IN INFRARED IMAGING

Mooney describes the quest for a high-temperature infrared imaging device and shows how platinum silicide complements charge-coupled devices in achieving that end.
Synthesis and structural and spectroscopic characterization of the germanazene [GeN(2,6-i-Pr2C6H3)]3 and the tin and lead tetramers [SnN(BMes2)]4, [SnN(2,6-i-Pr2C6H3)]4, and [PbN(2,6-i-Pr2C6H3)]4

The reactions of M(N(SiMe{sub 3}){sub 2}){sub 2} (M = Ge, Sn, Pb) with two bulky primary amines have been investigated. When Ge(N(SiMe{sub 3}){sub 2}){sub 2} was treated with H{sub 2}N(Dipp) (Dipp = 2,6-i-Pr{sub 2}C{sub 6}H{sub 3}), the trimeric species (GeN(Dipp)){sub 3} (1) was formed in high yield. The reaction of Sn(N(SiMe{sub 3}){sub 2}){sub 2} with H{sub 2}N(Dipp) or the primary borylamine H{sub 2}NBMes{sub 2} gives the tetrameric species (SnN(Dipp)){sub 4} (2) and (SnN(BMes{sub 2})){sub 4} (3). The lead compound (PbN(2,6-i-Pr{sub 2}C{sub 6}H{sub 3})){sub 4} (4) was prepared in a similar manner. Details of the {sup 1}H NMR spectroscopy and X-ray crystal structures of all compounds are reported. The trimer (GeN(Dipp)){sub 3} (1), which was described in a preliminary communication, has a planar Ge{sub 3}N{sub 3} ring structure with stereochemically active Ge lone pairs. The structures of 2-4 are tetrameric, featuring Sn{sub 4}N{sub 4} or Pb{sub 4}N{sub 4} cubane skeletons. The data suggest considerable ionic character in the M-N bonds.
Effects of sodium and lithium environments on mechanical properties of ferrous alloys

Abstract A review of the current status of work on the mechanical properties of structural materials in liquid sodium and lithium environments is presented. The influence of the environment as well as the effects of the microstructural and compositional changes that occur in austenitic and ferritic steels during long-term exposure are discussed. Requirements for additional data on mechanical properties are identified.
Oblique flow onto a growing crystal interface: An exact solution

Abstract Similarity solutions to the equations governing the steady transport of momentum, heat and solute for a model problem concerning the growth of a crystal from a dilute binary liquid have been obtained for the case of a two dimensional forced flow onto a steadily growing interface. The solutions obtained represent a non-parallel flow which is oblique to the solid-liquid interface.
The success of protest groups: Multivariate analyses

This paper reviews earlier research and presents new analytical findings regarding the outcomes of social movements. Using the resource mobilization/management approach, empirical propositions that seek to explain protest group success or failure are tested. Based upon data gathered from a sample of 53 US protest groups, the causal models explained the majority of the variance in degree of success between these groups. Our findings indicate that protest groups which threaten to replace or destroy established groups are usually unsuccessful, and those having many strong alliances tend to be more successful than groups fighting alone. The use of violence does not greatly aid the prediction of group outcome because of the unpredictable, ambivalent reaction to violence by established groups.
The preparation of diazine derivatives containing the ferroin group

With the idea of providing new compounds capable of chelation with metal ions, certain derivatives of diazines, containing the ferroin (NCCN) group have been prepared.
Outbreak of Necrotizing Enterocolitis Caused by Norovirus in a Neonatal Intensive Care Unit

Objectives To investigate an outbreak of necrotizing enterocolitis (NEC) in a neonatal intensive care unit (NICU) and to identify the etiology, describe illness risk factors, and develop control measures. Study design A retrospective case-control study was performed including newborns with NEC and newborns without NEC, examining demographic factors and exposures to medications, staff members, and procedures before illness. Stool samples from affected newborns were collected and tested for bacteria, parasites, and viruses. Results We confirmed a NEC outbreak in the NICU in January 1998 with 8 cases, including 2 deaths, clustered in time and space. Norovirus-like particles were identified in all available stools from cases; norovirus (NoV) was confirmed with reverse transcriptase polymerase chain reaction in 4 of 6 samples. NEC cases were younger, had lower Apgar scores, and received antibiotics longer than 25 control subjects. Three NICU health care personnel had more contact with cases than control subjects; 1 staff member recalled having gastroenteritis symptoms around the time of the outbreak. Conclusions This report associates NoV with NEC. NoV appeared to precipitate NEC in predisposed infants. Spatial clustering and epidemiologic links between cases and a health care worker with gastroenteritis suggests that NoV should be investigated among the etiologies of NEC outbreaks and that interventions targeted to interruption of NoV transmission should be considered.
Temperature Distribution and Heat-Transfer Results for an Internally Cooled, Heat-Generating Solid

An investigation was made of the temperature distribution and heat transfer in heat-generating solids which are internally cooled by circular flow passages. Under the conditions of hydrodynamically and thermally fully developed flow and uniform internal heat generation in the solid, the temperature rises linearly in the direction of fluid flow. It was found that with increased spacing of passages, the temperature field about any passage is less and is less influenced by neighboring passages. The local heat flux was essentially uniform around the periphery of the cooling passage. (M.C.G.)
Imogen: a parallel 3D fluid and MHD code for GPUs

We present Imogen, a fully parallel code for simulating either the Euler or Ideal MHD equations, in two or three dimensions, on GPUs and GPU clusters. Fluid dynamic codes have historically been written entirely in either Fortran or C/C++. Imogen combines the power of GPU acceleration and compiled CUDA solver modules under the hood with the ease of development, ease of use, and ease of modification characteristic of interpreted languages as everything but the core numeric routines is written in Matlab.Our basic goal of writing a highly parallel and fast fluid simulation code driven by Matlab which is GPU accelerated and fully parallel has been largely achieved at this time. We have tested simulations with up to 350 million cells using as many as 50 GPUs on the University of Oregon's ACISS supercomputer, and see no technical reason we could not use many more. Depending on the complexity of the physics used, a single C2070 device can handle as many as 25 million computation cells and still achieve simulation rates as high as a few seconds per timestep. Even though the code runs in an interpreted environment, we have found that interpretation overhead is quite small. Tests simulations with a resolution of 83 found roughly 80ms per complete iteration of overhead on a test workstation, which would be no more than a few percent of the time used by a large simulation.We use a standard fluid scheme neatly summarized in [1] and the exactly ∇ • Β preserving magnetic update algorithm of [2]. Fluid and MHD problems are tested against Imogen and we find that its convergence is second order in both space and time. Because Imogen is a relatively new code, implementation and testing of support for extended physics is a continuous and ongoing process. The use of operator splitting means that new non-ideal effects can be implemented and tested without amending the fluid code.The structures which kernels follow depending on the specifics of the finite differencing they will be undertaking is examined for patterns. Common errors encountered in the development process are explored.In addition, work in progress on the application of Imogen to research into two astrophysical phenomenon, accretion shocks and the protostellar disks, is briefly presented. The linear instability of MHD shock waves for many/most possible parameters is established, and while there has been nonlinear work [3] it appears to largely be assumed that the distortion will keep growing and completely destroy the shock front in the nonlinear regime; We have observed severe distortion but have not seen a breakup. We also present early experiments in applying Imogen to differentially rotating disks.
Temperature coefficient of open thimble chambers

Data taken on the temperature dependence of A150 and graphite ionization chambers show a temperature dependence consistent with the volume coefficient of expansion of the chamber materials. For graphite chambers this effect is negligible, but for A150 the T dependence is some 20% less than expected from the ideal gas law. In cases when the highest accuracy is required this effect should be taken into account.
Write-read-write signal precompensation techniques for magnetic recording

Medium noise in magnetic recording has been shown to be caused in part by the magnetic microstructure of the medium, which is determined at the time of manufacture of the medium. Systems can be designed to exploit this spatial dependence to increase recording density. Signal precompensation to achieve this is described here using two possible models for medium noise: additive and multiplicative. Based upon recent experimental results, the multiplicative model should be the more realistic of the two models, and hence is discussed in more detail. The anticipated increase in performance is quantified in terms of the signals written on the medium and the noise power.
The School Performance of Immigrant Minorities: A Comparative View

The international and comparative literature on linguistic minorities reveals that immigrant youths of working-class backgrounds are frequently more suecessful in school than nonimmigrant students of similar class background, either majority or minority, if they receive all their schooling in their new homeland. Drawing directly on a case study of Punjabi Sikh farm families settled in California, this article explores the forces that enable immigrant young people to succeed academically, to the degree that they do, in spite of severe handicaps. MINORITY SCHOOL PERFORMANCE, EDUCATIONAL POLICY, LINGUISTIC MINORITIES, IMMIGRANTS, SOUTH ASIANS
Investigation of formally zerovalent Triphos iron complexes

The reduction of Triphos [PhP(CH2CH2PPh2)2] iron halide complexes has been explored, yielding formally zerovalent (κ3-Triphos)Fe(κ2-Triphos) and (κ3-Triphos)Fe(κ2-Bpy). Electrochemical analysis, coupled with the metrical parameters of (κ3-Triphos)Fe(κ2-Bpy), reveal an electronic structure consistent with a π-radical monoanion bipyridine chelate that is antiferromagnetically coupled to a low spin, Fe(I) metal center.
Microstructure of natural hydrate host sediments

There is worldwide interest in the study of natural gas hydrate because of its potential impact on world energy resources, control on seafloor stability, significance as a drilling hazard and probable impact on climate as a reservoir of a major greenhouse gas. Gas hydrates can (a) be free floating in the sediment matrix, (b) contact, but do not cement, existing sediment grains, or (c) actually cement and stiffen the bulk sediment. Seismic surveys, often used to prospect for hydrates over a large area, can provide knowledge of the location of large hydrate concentrations because the hydrates within the sediment pores modify seismic properties. The ability to image a sample at the grain scale and to determine the porosity, permeability and seismic profile is of great interest since these parameters can help in determining the location of hydrates with certainty. We report here on an investigation of the structure of methane hydrate sediments at the grain-size scale using the synchrotron radiation-based computed microtomography (CMT) technique. Work has started on the measurements of the changes occurring as tetrahydrofuran hydrate, a surrogate for methane hydrate, is formed in the sediment.
The Calculator for Concept Formation: A Clinical Status Study.

The focus of this clinical study was whether young, school-age children can be taught, with minimal instruction, to use and perceive successive punches of the counter button' of a handheld calculator as a means for performing certain counting activities associated with basic fact addition and subtraction. Tasks presented in individual interviews were designed to give information about the following questions.
The mechanism of cell elongation during lens fiber cell differentiation

Lens fiber cell formation is one of the most important events occurring during lens morphogenesis and growth. Primary fiber cell elongation in the posterior half of the lens vesicle establishes the basic pattern of lens cell distribution, a monolayer of epithelium on the anterior surface covering a mass of elongated fiber cells. Subsequent secondary fiber cell formation from the equatorial epithelial cells accounts for lens growth by successive addition of elongating cells to the periphery of the fiber mass. During these processes cells elongate to many times their original length. In addition to the importance of fiber cell formation during development, disturbances in this process may be associated with some kinds of congenital, drug-induced and radiation-induced cataracts (Weiss, 1975; Hanna, 1975; Worgul and Rothstein, 1975).
Future refining impacts of the clean air act amendments of 1990

Abstract An assessment of the future refining impacts of the U.S. Clean Air Act Amendments of 1990 has been performed with the Navy Mobility Fuels Forecasting System. In 1992, the Environmental Protection Agency (EPA) should finalize precise requirements for Phase I reformulated gasoline, to be produced in 1995–1999. EPA requirements for Phase II reformulated gasoline, to be produced after 1999, will not be established until 1993. The assessment of refining impacts assumes that reformulated gasoline with likely Phase I specifications will be produced for markets projected for the year 2000. The assessment suggests that gasoline reformulation costs in U.S. coastal and near-coastal refining regions could be 3.5 to 5.6 cents per gallon (1989 U.S. currency). The relative value of MTBE is the most important determinant of the reformulation cost. For mileage equivalent to one gallon of conventional gasoline, the regional total added costs (including reformulation costs) for reformulated gasoline could be 5.2 to 7.6 cents. In blending reformulated gasolines, the reduction of butane for lower Reid vapor pressure and the reduction of reformate for lower aromatics are generally compensated by increased percentages of alkylate and/or straight run naphthas. Relatively larger refinery process capacity additions are required for butane isomerization, alkylation, aromatics recovery, and distillate hydrotreating.
Zero assignment in a time delayed continuous system for active vibration control

Active control of undesirable vibrations in structures, such as automobiles, rotors, air/space crafts, buildings, bridges etc., can be realized by pole and/or zero assignment. The Pole assignment problems in active control deals with reassigning a small set of unwanted eigenvalues and/or eigenvectors by using feedback control force to suitably chosen desired location, whereas the suppression of the amplitude of vibration at the desired location in the structure is known as zero assignment. Real time implementation of an active control strategy requires incorporation of the inherent time delay in the feedback loop for control gain computations. In this paper, methods for obtaining closed form solution of control gains for active zero assignment in a non-uniform distributed parameter system is presented while considering a small time delay in a feedback loop. The absorption strategy is demonstrated with examples. Effect of the time delay in control gains is studied and issues related to system stability are briefly discussed.
Novel tri-modal defect structure in Nb-doped MOCVD Y Ba2Cu3O7: a paradigm for pinning landscape control

Immobilization of vortices, or flux pinning, is both an enduring scientific issue and one of the most important problems in optimizing high temperature superconductors (HTSs) for commercial use. Here, we demonstrate a practical approach to the creation of a multi-modal flux pinning landscape in Y Ba2Cu3O7 (YBCO) films employing an industrially scalable metal–organic chemical vapor deposition technique. Through controlled additions of Nb, we have achieved a novel distribution of crystallographic defects that immobilize (pin) vortices in the YBCO matrix. That is, with only the addition of a single dopant element, a tri-modal, non-superconducting defect structure is induced that threads through the YBCO matrix laterally (parallel to the ab planes of YBCO), vertically (parallel to the YBCO c-axis), and isotropically in the form of random spherical defects. For optimally doped samples, the influence of these multi-modal nanocrystalline defect structures on the flux pinning properties manifests itself as a significant improvement in the critical current density (Jc) for all magnetic field orientations. The results demonstrate the possibility of achieving an ideal flux pinning landscape (from an orientation and strength viewpoint), which permits the design of HTS wires with fully-tunable properties by processes suitable for large-scale manufacturing.
Disruption of tactile discrimination in rats by bilateral stimulation of midbrain lemniscal pathways

Bilateral stimulation in the midbrain medial lemniscus disrupted tactile discrimination in four of nine rats. Single conditioning shocks in the midbrain of these animals attenuated by more than 80% the somatosensory cortical evoked responses elicited by test shocks to the contralateral forepaw. Midbrain stimulation did not selectively disrupt discrimination in the remaining five rats, and midbrain conditioning shocks attenuated the cortical test response by less than 80% on at least one side. The four rats that showed disrupted discrimination and bilaterally strong attenuation of cortical responses also had both midbrain electrodes in or next to the medial lemniscus. The five rats that did not show these effects had at least one midbrain electrode away from that structure.
Development of ultrafast laser-plasma X-ray sources for time-resolved absorption studies in the 4-5 keV energy range

Summary form only given. We present the progress in the optimization of laser produced plasma sources, specifically aimed the 4-5 keV X-ray energy range, using Ti and Ta wire and plane targets. Two table-top Chirped Pulse Amplification (CPA) laser systems were used: the INRS CPA laser (Nd:glass second harmonic @532 nm, 400 fs, 400 mJ, high pulse/pedestal contrast ratio, low repetition rate), and the UCSD CPA laser (Ti:sapphire @800 nm, 30 fs, 100 mJ 20 Hz repetition rate). The spectra of the emitted radiation were analyzed by the combination of a curved Si crystal spectrometer and an X-ray CCD camera arrangement. The PX-1 X-ray streak camera of INRS has also been used to follow the time history of multi-keV X-ray emission with subpicosecond temporal resolution. Comparison of the data collected with the two systems (INRS vs. UCSD) suggests the important role of the pre-pulse in achieving the maximum yield in a particular emission wavelength range. The pulse duration of the excitation pulses also has a strong effect in controlling the hot electron production processes in the rapidly expanding solid density plasma. Preliminary experiments on static absorption spectra of iodine at the L-III edge gave important data (photon statistics, signal-to-noise ratio) for designing future time-resolved EXAFS experiments based on laser produced X-ray sources.
Image–Guided Ex vivo Liver Ablation by Unfocused Ultrasound using Passive Cavitation Detection

ABSTRACT Ablation therapy is used as an alternative to surgical resection of hepatic tumors. In ablation, tumors are destroyed through heating by RF current, high intens ity focused ultrasound (HIFU), or other energy sources. Ablation can be performed with a linear array transducer delivering unfocused intense ultrasound (>10 W/cm 2 ). This allows simultaneous treatment and imagi ng, a feature uncommon in RF ablation. Unfocused ultrasound can also enable faster bulk tissue ablation than HIFU. In the experiments reported here, a 32-element linear a rray transducer with a 49 mm aperture delivers 3.1 MHz continuous wave unfocused u ltrasound at amplitudes 0.71.4 MPa during the therapy cycle. It also operates in pulse-echo mode to capture B-scan images. Ex-vivo fresh bovine liver tissue placed in degassed saline is exposed to continuous wave ultrasound interleaved with brief pulsed ultrasound imaging cycles. Tissue exposures range between 5 to 20 minutes. The follo wing measurements are made at intervals of 1 to 3 seconds: tissue temperature with a needle thermocouple, acoustic emissions with a 1 MHz passive unfocused detector, and tissue echogenicity from image brightness. Passively detected acoustic emissions are used to quantify cavitation activity in the ablation experiments presented here. As severity and extent of tissue ablation ar e related to temperature, this paper will statistically model temperature as a function of tissue echogenicity and cavitation. The latter two quantities can potentially be monitored noninvasively and used as a surrogate for temperature, enabling improved image guidance and control of ultrasound ablation. KEYWORDS: Ultrasound ablation, Cavitation, Logistic regression, Temperature, Monitoring, Statistical Modeling 1. INTRODUCTION
Previous abdominal colectomy affects functional results after ileal pouch-anal anastomosis

We assessed the effect of previous abdominal colectomy on functional results after ileal “J” pouch-anal anastomosis (IPAA) in patients with ulcerative colitis. Twenty-five patients with colectomy prior to IPAA were compared with 22 patients who underwent noncolonic abdominal operations prior to IPAA. No differences were observed in pre- or postoperative resting anal sphincter pressure, squeeze pressure, or rectal inhibitory reflex. Previous colectomy was associated with a greater incidence of postoperative small bowel obstruction. Mean ± SEM daily stool frequency at 1 and 12 months postoperatively, respectively, was 8.9±0.8 and 5.7±0.3 for patients who had undergone previous colectomy, and 8.2±0.7 and 6.0±0.5 for the no previous colectomy group (p=not significant). At the same postoperative intervals, nocturnal stool frequency was 1.9±0.3 and 1.1±0.2 for the colectomy group and 1.5±0.3 and 0.6±0.1 for the no colectomy group (p=0.05 at 1 year). More patients in the previous colectomy group had greater than or equal to 1 nocturnal stool after 1 year (71% versus 33%,p=0.03). Although pouch capacity at 1 year was not different in the 2 groups, pouch capacity was directly related to stool frequency in the no colectomy group (r2=0.48,p=0.01), but not in the previous colectomy group (r2= 0.08,p=not significant). We conclude that previous abdominal colectomy may be associated with a higher overall incidence of small bowel obstruction. Moreover, previous colectomy is a determinant of postoperative nocturnal stool frequency after IPAA, most likely due to altered ileal pouch function. When possible, single-stage colectomy, mucosal proctectomy, and endorectal ileal pouch-anal anastomosis should be performed in patients requiring colectomy for ulcerative colitis.
Response sequence learning as a function of primary versus conditioned reinforcement

Two groups of pigeons were required to generate a fixed sequence of responses on three keys, for example, middle-left-right. One group received a small food reward (SFood) following each correct response except the terminal one, which was followed by a large food reward. The second group received conditioned reinforcement from an overhead light (SLight) for each correct response, with the terminal correct response followed by both SLight and the large food reward. We manipulated length of sequence (3 or 7 responses) and duration of required interresponse interval (IRI; 1 to 9 sec). SLight contingencies generated more accurate performances than did SFood when sequence length was 3 responses but not when it was 7 responses. IRI duration influenced accuracy under the SLight contingencies but not under SFood. These results show that conditioned reinforcers sometimes generate more accurate sequence learning than do primary reinforcers, and that schedule contigencies influence which type of feedback will optimize performance. The results parallel those from the matching-to-sample and conditional discrimination literature.
Microbial degradation of hydrazine.

Hydrazine is toxic to many forms of bacteria. The activities of the autotrophic nitrifiers Nitrosomonas and Nitrobacter, denitrifying bacteria, and anaerobic methanogens were inhibited by the chemical. In addition, hydrazine prolonged the lag phase of growth as well as inhibited growth of the soil bacterium Enterobacter cloacae. Due to rapid disappearance in soil, hydrazine at 100 ..mu..g/g exhibited only temporary inhibition on soil bacterial populations. However, hydrazine at 500 ..mu..g/g caused a significant reduction of soil bacterial populations, although fungal populations in soil were enhanced by the presence of hydrazine. Despite its toxicity to soil bacteria, hydrazine in small quantities was cometabolically degraded to nitrogen gas by Nitrosomonas. An enzyme system of nitrogen-fixing heterotrophic bacteria was able to convert hydrazine to ammonia. However, it was not clear that the bacteria could utilize hydrazine as a sole source of nitrogen for growth. In the present study, the authors describe the isolation of an Achromobacter sp. from soil that had a high capacity to degrade hydrazine. Attempts to establish degradation pathways are also reported.
Supporting configuration and deployment of component-based DRE systems using frameworks, models, and aspects

This research focuses on using frameworks, model-driven development, and aspect-oriented software development techniques to address key configuration and deployment concerns of component-based distributed real-time and embedded (DRE) systems. System designers and deployers can use these techniques to configure quality of service (QoS) aspects of their systems and fine-tune their systems during the design and runtime phases to ensure their systems meet end-to-end performance requirements.
The Vibrational Spectrum and Specific Heat of a Face-Centered Cubic Crystal

The frequency spectrum of a face-centered cubic crystal lattice is found by actually modeling the constant-frequency surfaces of the secular determinant in plaster of Paris and measuring the volume enclosed between successive surfaces. The frequency spectrum so obtained is used in the evaluation of the specific heat of a general crystal of the type treated, and numerical values are presented for the element silver. The present theory (that of Born and v. Karman) is in much better agreement with experimental values for temperatures below 100°K than is the Debye theory. Certain anomalies in the specific heat curves of silver and potassium chloride at temperatures below 10°K are not explicable in terms of the atomic model that is used.
Exploiting overlapping channels for minimum power configuration in real-time sensor networks

Multi-channel communications can effectively reduce channel competition and interferences in a wireless sensor network, and thus achieve increased throughput and improved end-to-end delay guarantees with reduced power consumption. However, existing work relies only on a small number of orthogonal channels, resulting in degraded performance when a large number of data flows need to be transmitted on different channels. In this paper, we conduct empirical studies to investigate the interferences among overlapping channels. Our results show that overlapping channels can also be utilized for improved real-time performance if the node transmission power is carefully configured. In order to minimize the overall power consumption of a network with multiple data flows under end-to-end delay constraints, we formulate a constrained optimization problem to configure the transmission power level for every node and assign overlapping channels to different data flows. Since the optimization problem has an exponential computational complexity, we then present a heuristic algorithm designed based on Simulated Annealing to find a suboptimal solution. Our empirical results on a 25-mote testbed demonstrate that our algorithm achieves better real-time performance and less power consumption than two baselines including a scheme using only orthogonal channels.