cssi/SciSciGPT-SciSciNet huggingface dataset:
Low Reynolds number flow through nozzle-diffuser elements in valveless micropumps

Flow characteristics of low Reynolds number laminar flow through gradually expanding conical and planar diffusers were investigated. Such diffusers are used in valveless micropumps to effect flow rectification and thus lead to pumping action in one preferential direction. Four different types of diffuser flows are considered: fully developed and thin inlet boundary layer flows through conical and planar diffusers. The results from the numerical analysis have been quantified in terms of pressure loss coefficient. The variation of pressure loss coefficient with diffuser angle is presented for Reynolds numbers of 200, 500 and 1000. The pressure loss coefficients have been used to calculate the diffuser efficiency for two different types of nozzle-diffuser elements. The general trend of variation of pressure loss coefficient with diffuser angle was found to be similar to that for high Reynolds number turbulent flow. However, unlike at high Reynolds numbers, pressure loss coefficients at low Reynolds numbers vary significantly with Reynolds number. It was also observed that trends of variation in the pressure loss coefficient with Reynolds number are different for small and large diffuser angles. Also, at low Reynolds numbers, the pressure loss coefficients for a thin inlet boundary layer are not always smaller than those for fully developed inlet boundary layer, in contrast to the behavior for high Reynolds number flows. Contrary to past claims, flow rectification is shown to be indeed possible for laminar flows. The two different types of nozzle-diffuser elements considered led to pumping action in opposite directions. Further, it was observed that flow rectification properties of both kinds of nozzle-diffuser elements improved with increasing Reynolds number.
Field ionization energy spectra of molecules

Abstract Considerations for determination of the partition of internal energy in ion s formed by field ionization are discussed in terms of the distribution of ion energies. Experimental high-resolution energy spectra for the molecular ions produced by field ionization of toluene, cycloheptatriene, phenol, hydrogen and carbon monoxide are shown and discussed. In particular it is concluded that the range of internal energies can be of the order of several electron volts. Implications of the observations for rate predictions are discussed.
School Bonding, Race, and Delinquency

While there is considerable evidence that blacks experience school in qualitatively distinct ways from whites, there has been a general failure to examine racial variation in the impact of school variables on juvenile misconduct. The purpose of this research is to describe the manner in which school bonding affects delinquent conduct, focusing in particular on the role of the school in the delinquent involvement of black youths. Our orientation is primarily a control theory one that suggests that the greater the degree of school bonding the lesser the likelihood of involvement in delinquent activities. Our review of the literature leads us to expect differential levels of bonding by race and across varying racial environments of schools, with resulting differential effects on delinquency. On the basis of a neighborhood sample of 942 adolescents, we identijj seven distinct dimensions of school bonding. The analysis reveals that blacks are at least as strongly bonded to the school as whites, that our model explains comparable amounts of variance in delinquency across race-sex subgroups, and that the racial composition of the school is generally unimportant in conditioning the effect of school bonding on delinquency. While our findings are generally supportive of control theory, a model that purports to be invariant across race, gender, and socioeconomic boundaries, we caution that such a conclusion may be both premature and mistaken. We discuss the implications of these findings and suggest that they be interpreted within a framework that also considers family and peer bonding.
A methane flux transect along the trans-Alaska pipeline haul road

Methane flux measurements were made during the summer of 1987 at 10 km intervals along a north–south transect from Prudhoe Bay (70°13′N) to the Arctic Circle (66°30′N) in Alaska. A regional comparison showed that the mean CH 4 flux from arctic tundra (52 mg m -2 d -1 ) was significantly greater than the mean from high latitude taiga (11 mg m -2 d -1 ). Sites occupied on the transect were classified into 6 categories based on differences in plant communities and CH 4 emission was further compared. Mean CH 4 fluxes (mg m -2 d -1 ) for each category were: wet tundra, 90; low brush-muskeg bog, 45; moist tundra, 31; freshwater ponds, 21; spruce forest, 4.6; and alpine tundra, 0.6. Differences among means were statistically significant. During the period of observation, CH 4 emission was only weakly correlated with soil temperature, water table depth, thaw depth and organic layer depth. Extending these fluxes to appropriate areas and emission periods yields independent estimates of annual CH 4 emission from global tundra and taiga environments of 38 Tg and 15 Tg. This is about 46% of the wetland emission term or 10% of the global atmospheric input. DOI: 10.1034/j.1600-0889.1990.t01-2-00002.x
The Clinical Significance of Somatic Pain Tolerance in Patients with Coronary Artery Disease

Methods Two hundred seventy-one patients with a recent acute coronary event underwent pain tolerance testing using the tourniquet test. Baseline ambulatory and exercise electrocardiography, and stress thallium scintigraphy were performed, and patients were followed prospectively for a mean of 33 ± 8 months for the occurrence of unstable angina, nonfatal myocardial infarction (Ml), or cardiac death. Results Patients with lower tolerance to somatic pain were significantly older (P = 0.001), had more clinical angina (P = 0.04), and on multivariate analysis had poorer exercise tolerance (P = 0.002) than those with higher pain tolerance. Low and high pain tolerance patients demonstrated similar degrees of myocardial ischemia on noninvasive testing and had similar cardiac event rates (death, nonfatal Ml, or unstable angina) during the follow-up period. Conclusions Despite demonstrating a similar frequency of myocardial ischemia and similar prognosis as patients with high pain tolerance, individuals with low pain tolerance were more likely to experience clinical symptoms and functional impairment, providing evidence that individual differences in somatic pain tolerance influence the symptomatic expression of coronary disease.
Parallel effects of genetic variation in ACE activity in baboons and humans.

Like humans, savannah baboons (Papio sp.) show heritable interindividual variation in complex physiological phenotypes. One prominent example of such variation involves production of the homeostatic regulator protein angiotensin converting enzyme (ACE), which shows heritable variation in both baboons and humans. In humans, this phenotypic variation is associ- ated with an Alu insertion-deletion polymorphism in the ACE gene, which explains approximately half of the var- iation in serum ACE activity. We identified a similar Alu insertion-deletion polymorphism in the baboon ACE homologue and measured its frequency in a wild popula- tion and a captive population of baboons. We also ana- lyzed the contribution of ACE genotype at this indel to variation in serum ACE activity in the captive popula- tion. When conditioned on weight, a known factor affect- ing ACE activity in humans, age and ACE genotype both accounted for variance in ACE activity; in particular, we identified a significant nonadditive interaction between age and genotype. A model incorporating this interaction effect explained 21.6% of the variation in residual serum ACE activity. Individuals homozygous for the deletion mutation exhibited significantly higher levels of ACE activ- ity than insertion-deletion heterozygotes at younger ages (10-14 years), but showed a trend towards lower levels of ACE activity compared with heterozygotes at older ages (� 15 years). These results demonstrate an interesting par- allel between the genetic architecture underlying ACE var- iation in humans and baboons, suggesting that further attention should be paid in humans to the relationship between ACE genetic variation and aging. Am J Phys
Children and violence.

Ask the Expert provides answers to clinical questions for nurses in practice settings. Where possible, evidence from research is used to support the experts' recommendations.
Probing the Interior of a Secretory Granule

Although a great deal is known about events leading to the release of secretory granule contents into the extracellular space, little is known about the physical state of the granule lumenal contents prior to exocytosis. We have used TIRFM as our core technique and combined it with either Fluorescent Correlation Spectroscopy (FCS) or Fluorescence Recovery After Photobleaching (FRAP) to assess the mobility of either Neuropeptide Y (NPY) or tissue plasminogen activator (tPA) inside chromaffin granules (300 nm diameter). Overall granule motion was taken into account by viewing simultaneously in the same granule one subset of protein molecules labeled with cerulean and the other with mCherry. Theories for separating out the effects of granule motion for both FCS and FRAP measurements were derived. The rapidly decaying evanescent field (decay constant ∼ 110 nm) enables a small measurement volume in FCS. The fluorescence fluctuations of the fluorophore diffusing into and out of the measurement volume had a characteristic correlation time of several hundred milliseconds. The rapidly decaying evanescent field also allows a spatially restricted bleaching of the granule fluorophore in FRAP, thereby permitting recovery by diffusion from unbleached volume within the granule. FRAP and FCS results were consistent. These initial measurements suggest a diffusion coefficient of these proteins of the order of 10-10 cm2/s, at least two orders of magnitude slower than soluble proteins in cytosol. Our initial results, therefore, indicate highly restricted protein mobility within secretory granules. Research support from NIH Grant R21NS073686 to RWH and DA.
The Lambek calculus enriched with additional connectives

Some formal properties of enriched systems of Lambek calculus with analogues of conjunction and disjunction are investigated. In particular, it is proved that the class of languages recognizable by the Lambek calculus with added intersective conjunction properly includes the class of finite intersections of context-free languages.
The effect of composition on interdiffusion in ternary alloys

Abstract When the composition of one end of a ternary diffusion couple is varied, there are changes which occur in the penetration curves, diffusion paths, interdiffusion rates and zero-flux planes. These changes are described and classified for single phase, constant diffusivity systems. It is shown that all classes of behavior can be found in any ternary system and that the limiting conditions for each class depend on the square root of the diffusivity matrix. In addition, the ternary diffusion equations are formulated in terms of both the square root matrix and the composition vector between terminal alloys. It is shown that the location or occurrence of zero-flux planes and penetration curve extrema is independent of the magnitude of the composition vector. However, concentration differences on penetration curves, diffusion path deviations and rate constants are all proportional to the magnitude of the composition vector. Numerical examples based on the diffusivity of a Ni-10Cr-8Al alloy are used to illustrate the various types of interdiffusion behavior.
SHOULD WE TEACH CHILDREN SYNTAX

Two research studies on child L2 acquisition were conducted sequentially over the last year. The first study used comparative error analysis to determine whether the actual L2 errors children make can be accounted for by “creative construction” or “habit formation.” The findings provided the impetus for the second study which compared the sequence of acquisition of certain grammatical morphemes in three different groups of children, using a cross-sectional technique. The combined findings of the two studies suggest that, given a natural communication situation, children's innate ability to organize structure accounts in a major way for their acquisition of L2 syntax. Although we believe that an L2 teacher should continue to diagnose children's L2 speech, our findings suggest that we should leave the learning of syntax to the children and redirect our teaching efforts. Practical suggestions are offered to help create speech environments in the classroom that capitalize on the child's natural language learning processes.
Femtosecond Pump−Probe Transient Absorption Study of the Photolysis of [Cp‘Mo(CO)3]2 (Cp‘ = η5-C5H4CH3): Role of Translational and Rotational Diffusion in the Radical Cage Effect

Femtosecond pump−probe studies of the photodissociation and subsequent radical cage pair recombination dynamics of the organometallic dimer [Cp‘Mo(CO)3]2 (Cp‘ = η5-C5H4CH3) are reported. The dynamics following photodissociation were studied in numerous noncoordinating hydrocarbon solvents. The results indicate that primary geminate recombination occurs on an ultrafast time scale (τ ≈ 5 ps) and the efficiency of cage escape is inversely proportional to solvent viscosity. Investigation of the time-dependent anisotropy in this system allowed for an estimate of the rotational correlation time of the radical fragments (τ ≈ 5−25 ps). Comparison of the rates of rotational motion with the population kinetics shows that the primary solvent cage dynamics and recombination efficiency are controlled by radical diffusion and not by radical rotation.
The methylerythritol phosphate pathway contributes to carotenoid but not phytol biosynthesis in Euglena gracilis.

The biosynthesis of diadinoxanthin and β-carotene in Euglena gracilis was examined using [1-13C]-d-glucose and [5,5-2H2]-1-deoxy-d-xylulose. In contrast to previous studies on isoprenoid biosynthesis in E. gracilis, the results demonstrate a role for the methylerythritol phosphate (MEP) pathway, along with the mevalonate pathway, in carotenoid biosynthesis. Interestingly, the MEP pathway is not involved in the biosynthesis of phytol, a result not previously observed for other chloroplast-containing organisms.
Water and sunlight: regenerative hydronics

Hydronic technologies are undergoing significant transformations in an attempt to revolutionise resource independence in buildings. On-site energy generation and waste regeneration are at the centre of this potential paradigm shift. This text initially discusses recent developments in hydronics systems regarding energy source, materiality, distribution and location in buildings, and plenum typology. Secondly, it evaluates emerging innovation in water-based radiation geared particularly toward zero net energy buildings. Lastly, the text presents current research in hydronic technology in which water heating and disinfection are fully integrated into a facade system through microoptics integration. This discussion contributes to the evaluation of incorporating microoptics into future building technologies in which water, waste, and energy are synergistically balanced. The integration of microoptics can fuel radical innovation leaps in this front enabling regenerative hydronics.
Hamstring anterior cruciate ligament reconstruction: a comparison of bioabsorbable interference screw and endobutton-post fixation.

Abstract Purpose The purpose of this study was to evaluate hamstring anterior cruciate ligament (ACL) reconstruction using aperture fixation with bioabsorbable interference screw (BIS) and distant fixation using EndoButton (Smith & Nephew, Andover, MA) and screw-post (ENDO). Type of study Prospective nonrandomized clinical outcome study. Methods Two groups of 15 patients who underwent autogenous hamstring ACL reconstruction with a minimum of 2 years' follow-up evaluation (mean 35 months) were included in the study. The BIS group underwent poly-L-lactic acid interference screw fixation at both femoral and tibial tunnels and the ENDO group underwent EndoButton fixation on the femoral side and screw-post fixation on the tibial side. Clinical evaluation included International Knee Documentation Committee (IKDC) and arthrometer measurements. Tunnel enlargement, screw integrity, graft integrity, and graft-tunnel interface were evaluated using radiographs and magnetic resonance imaging. Statistical analyses were performed using the Student t test, with significance set at 0.05. Results All patients in both groups had functionally normal or near-normal IKDC scores. The average IKDC subjective knee form scores were 85 ± 11 versus 81 ± 17 (BIS v ENDO) and side-to-side KT differences were 3.2 ± 2.6 mm versus 2.4 ± 1.8 mm ( P > .05). For both groups, tunnel enlargement was present on radiographs at both femoral and tibial sides (36% to 77%). Tunnel enlargement was more significant at the femoral tunnels (53% to 77%) than the tibial tunnels (36% to 42%). In the BIS group, magnetic resonance imaging revealed 9 partially degraded screws and 2 intact screws on the femoral side. On the tibial side, 4 partially degraded and 10 intact screws were seen. For both groups, the grafts have partial or complete incorporation at all tunnels. Tunnel enlargement measured on radiographs correlate well with measurements on magnetic resonance images. Conclusions Our results showed that rigid aperture fixation using BIS did not lead to significant differences in clinical outcome when compared with distant fixation using ENDO at 24 to 40 months follow-up evaluation. Significant tunnel enlargement was present in both groups, more pronounced on the femoral side. Magnetic resonance imaging findings showed that BIS were not degraded even at 2 to 4 years after surgery. Level of evidence Level II.
Functional Coupling Between Glycolysis and Sarcoplasmic Reticulum Ca2+ Transport

To investigate whether the energy derived from glycolysis is functionally coupled to Ca2+ active transport in sarcoplasmic reticulum (SR), we determined whether glycolytic enzymes were associated with SR membranes and whether metabolism through these enzymes was capable of supporting 45Ca transport. Sealed right-side-out SR vesicles were isolated by step sucrose gradient from rabbit skeletal and cardiac muscle. Intravesicular 45Ca transport was measured after the addition of glycolytic substrates and cofactors specific for each of the glycolytic reactions being studied or after the addition of exogenous ATP and was expressed as transport sensitive to the specific Ca(2+)-ATPase inhibitor thapsigargin. We found that the entire chain of glycolytic enzymes from aldolase onward, including aldolase, GAPDH, phosphoglycerate kinase (PGK), phosphoglyceromutase, enolase, and pyruvate kinase (PK), was associated with SR vesicles from both cardiac and skeletal muscle. Iodoacetic acid, an inhibitor of GAPDH, eliminated 45Ca transport supported by fructose-1,6-diphosphate, the substrate for aldolase, but transport was completely restored by phosphoenolpyruvate (the substrate for PK), indicating that both of the ATP-producing glycolytic enzymes, GAPDH/PGK and PK, were associated with the SR and functionally capable of providing ATP for the Ca2+ pump. Addition of a soluble hexokinase ATP trap eliminated 45Ca transport fueled by exogenous ATP but had markedly less effect on 45Ca transport supported by endogenously produced ATP (via glycolysis). Similarly, at very low concentrations of ATP and ADP (10 to 50 nmol/L), ATP that was produced endogenously from ADP and phosphoenolpyruvate supported 15-fold more 45Ca transport than ATP that was supplied exogenously at the same concentration. These results are consistent with functional coupling of glycolytic ATP to Ca2+ transport and support the hypothesis that ATP generated by SR-associated glycolytic enzymes may play an important role in cellular Ca2+ homeostasis by driving the SR Ca2+ pump.
Hyaluronic acid: structure of a fully extended 3-fold helical sodium salt and comparison with the less extended 4-fold helical forms.

The structure of sodium hyaluronate packed in a trigonal lattice (a = b = 1·17 nm, c (fiber axis) = 2·850 nm, γ = 120°) has been determined and refined against X-ray diffraction data and a quadratic approximation to non-bonded repulsion. The polysaccharide chain is a regular, left-handed 3-fold helix stabilized by O --- O intramolecular hydrogen bonds across the two kinds of glycosidic linkage. The hydroxymethyl side chain is oriented approximately gauche-gauche and the plane of the acetamido side chain is approximately normal to the helix axis. Two such chains pass through the unit cell in opposite directions intersecting the base plane at (xf = 2/3, yf = 1/3) and (xf = 1/3, yf = 2/3). The two chains are related by the dyad axis symmetry of the space group, P3221. Each carboxylate group is bound to one sodium ion which in turn binds to two oxygen atoms from a second polyanion chain and three water molecules. One of these water molecules is located in a crystallographic special position on the x,x,0 dyad and is therefore shared by two Na+ co-ordination shells. Most of the inter-chain hydrogen bonding involves water bridges and there is no direct bonding between acetamido side chains. The structure is compared to other forms of hyaluronic acid and the consequences of the different forms of intermolecular associations are considered in detail.
Can Reduction in Dietary Carbohydrate Play a Role in Normalizing the Endocrine-Metabolic State Perturbed During the Pubertal Transition? The PRIMO Pilot Study:

Macronutrient modification may play a role in normalizing the endocrine-metabolic state characteristically perturbed during the pubertal transition. This study evaluated the effect of a reduced car...
Kinetic analysis of human IL-2 activated cytotoxic cells.

AbstractKinetic analysis was used to define lytic events in peripheral blood mnonuclear cells (Pm) activated in lymphkine conditioned medium (LCM) and recanbinant interleukin-2 (rIL-2). This analysis provided quantitative information on the functional properties of these lymphkine-activated killer (LAK) cells against NK-resistant and NK-sensitive tumor cell lines. the maximum rate of target cell lysis (Vmax) and Km (target cell number resulting in 1/2 Vmax) were determined. IL-2 activated effector cells that bound to target cells also lysed them (i.e., non-lytic bystander lymphocytes did not influence the determination of kinetic parmters) in contrast to lysis mediated by unactivated NK cells. the extent of LAK cell binding to tmr target cells was dependent upon the tumor type. LAK cell frequency determinations were calculated where Km approximated the concentration of LAK cells that were capable of killing a particular target. LAK cells generated in rIL-2 were lytically more efficient than those activate...
Chandra hardware and systems: keeping things running

System management for any organization can be a challenge, but satellite projects present their own issues. I will be presenting the network and system architecture chosen to support the scientists in the Chandra X-ray Center. My group provides the infrastructure for science data processing, mission planning, user support, archive support and software development. Our challenge is to create a stable environment with enough flexibility to roll with the changes during the mission. I'll discuss system and network choices, web service, backups, security and systems monitoring. Also, how to build infrastructure that's flexible, how to support a large group of scientists with a relatively small staff, what challenges we faced (anticipated and unanticipated) and what lessons we learned over the past 6 years since the launch of Chandra. Finally I'll outline our plans for the future including beowulf cluster support, an improved helpdesk system, methods for dealing with the explosive amount of data that needs to be managed.
Motor-evoked potentials in response to fatiguing grip exercise in multiple sclerosis patients

Abstract Objective : This study examined central and peripheral effects of fatiguing exercise (3 min maximal grip) in healthy controls ( n =10) and multiple sclerosis (MS) subjects with weakness, MS-W ( n =16) and normal motor function, MS-NM ( n =16) in the studied extremity. Method : Transcranial magnetic stimulation (TMS) was used to assess resting and facilitated motor-evoked potentials (MEPs) of abductor pollicus brevis (APB) and flexor carpi radialis (FCR) muscles before and after fatiguing exercise. Exercise-induced depletion and recovery of phosphocreatine (PCr) were measured using 31 P magnetic resonance spectroscopy ( 31 PMRS) in FCR. Results and conclusion : MS subjects demonstrated significantly lower peak force and a faster decline in force than controls. Contralateral muscle activation (hand grip) before the fatigue protocol resulted in significantly increased MEP amplitudes in all groups. Contralateral hand grip following fatiguing exercise resulted in significantly higher MEP amplitudes in controls and MS-NM subjects, but not MS-W subjects. Fatiguing exercise resulted in prolonged central motor conduction time (CMCT) in MS subjects, but not controls. No group differences in PCr depletion or resynthesis were observed. All groups demonstrated significant post-exercise depression (PED) of MEP amplitude that persisted beyond the time course of PCr recovery, indicating fatigue was central in origin. MS subjects were less able than controls to increase cortical excitability using contralateral muscle activation following fatiguing exercise, possibly indicating impaired conduction in the corpus callosum.
The Support of Multiple Data Streams in a Dynamically Configured Software System

This paper discusses a modular data-acquisition system that allows on-line, dynamic configuration of software to meet a user's particular acquisition and analysis needs. The support of multiple data streams, typically consisting of a raw data stream and one or more derived data streams, is emphasized. Examples are given, including a real-time data transformation of multiparameter events that operates in a two-parameter data space.
Pennsylvanian coalified rhizomorphs in Illinois: evidence for non‐compressive coalification to bituminous coal rank

Irregular and discontinuous coalified objects, here termed rhizomorphs, occur above the Summum (No. 4) Coal Member (Carbondale Formation) at one locality in La Salle County, Illinois. These vitrinite structures, varying between 3 mm and 4 cm in diameter, occur in a blocky to structureless mottled claystone characterized by numerous carbonaceous streaks and small-scale slickensides. The rhizomorphs twist and bend in a tightly coiled and kinked pattern, and may extend laterally through the claystone for 40 cm or more before bifurcating or terminating. The rhizomorphs display little or no evidence of compressive distortion. They are composed of two types of material: structureless bright conchoidal collinite; and cellular woody structure. One or more vascular bundles occur as discrete steles within a groundmass of collinite gel; these are generally aligned longitudinally within the coal except where steles diverge laterally as offshoots. The rhizomorphs are believed to be a diagenetic derivative of rooting structures; this is based on their occurrence in an underclay-like sediment and on their irregular, kinked form, which differs from that of most vertical supportive plant stems. Non-compressive coalification of the plant material may have occurred through: (1) aerobic alteration of cell walls to non-compressive inertinite; (2) centripetal contraction and selective degradation of plant tissue; and (3) impregnation of more resistant stelar elements by organic gel derived from degradation of thin-walled tissue.
A secure distributed framework for achieving k -anonymity

k-anonymity provides a measure of privacy protection by preventing re-identification of data to fewer than a group of k data items. While algorithms exist for producing k-anonymous data, the model has been that of a single source wanting to publish data. Due to privacy issues, it is common that data from different sites cannot be shared directly. Therefore, this paper presents a two-party framework along with an application that generates k-anonymous data from two vertically partitioned sources without disclosing data from one site to the other. The framework is privacy preserving in the sense that it satisfies the secure definition commonly defined in the literature of Secure Multiparty Computation.
Quantifying habitat loss: Assessing tree encroachment into a serpentine savanna using dendroecology and remote sensing

Abstract For over a century, increases in the abundance of woody plants in savannas have been occurring worldwide in a process known as encroachment. Encroachment into savannas is a significant management concern because it affects the unique values associated with savanna systems, including high levels of both taxonomic and landscape diversity. Improving methods for reconstructing encroachment patterns should aid savanna management, especially if the methods provide a baseline from which to assess and project ecological change. We reconstructed the encroachment history of a small serpentine Jeffrey pine savanna and forecasted future landscape change using two distinct approaches. First, we used dendroecology to determine encroachment rates, establish historical site reference conditions, and project tree-growth trends. Second, we used historical aerial photographs to construct a spatial model of past tree encroachment and to predict near future encroachment. We found encroachment began ∼1850 and was not related to differences in topography across the landscape. Trees greater than 30 cm in diameter have increased from a mean stem density of ∼1.6 trees per ha in 1890 to a mean stem density of ∼13.8 trees per ha in 2009. Concomitant with the increase in tree density and average tree size was the contraction of the grass-dominated areas of the savanna, which represented ∼50% of Little Bald Hills in 1942, but less than 10% in 2009. If current encroachment rates continue, our models suggest that less than 5% of Little Bald Hills will be grassland in 50 years. This is not the first study to utilize both historical photo analysis and dendroecology, but it is the first to use these tools to identify explicit locations where encroachment is likely to occur in the near future.
Noninvasive assessment of left ventricular assist devices with cardiovascular computed tomography and impact on management.

Background Left ventricular assist devices (LVADs) provide a bridge to recovery or heart transplantation but require serial assessment. Echocardiographic approaches may be limited by device artifact and acoustic window. Cardiovascular computed tomography (CCT) may provide improved non-invasive imaging of LVADs. We evaluated the diagnostic findings and clinical impact of CCT for non-invasive assessment of patients with LVADs. Methods CCT examinations performed between 2005 and 2008 in patients with LVADs were identified. Acquisitions were completed on the identical 64-detector-row scanner with intravenous contrast administration. Electrocardiographic gating was used in patients with pulsatile devices, and peripheral pulse gating was used in patients with continuous-flow devices. Comparison was made between CCT results and 30-day outcomes, including echocardiographic and intraoperative findings. Results We reviewed 32 CCT examinations from 28 patients. Indications included evaluation of low cardiac output symptoms, assessment of cannula position, low flow reading on the LVAD, and surgical planning. CCT identified critical findings in 6 patients, including thrombosis and inlet cannula malposition, all confirmed intraoperatively. CCT missed 1 case of intra-LVAD thrombus. Using intraoperative findings as the gold standard, CCT's sensitivity was 85% and specificity was 100%. Echocardiographic LVAD evaluation did not correlate with findings on CCT (κ = −0.29, 95% confidence interval, −0.73 to 0.13). Conclusions This preliminary observational cohort study indicates that non-invasive imaging using CCT of LVADs is feasible and accurate. CCT warrants consideration in the initial evaluation of symptomatic patients with LVADs.
Methodology for modeling and simulating line-end shortening effects in deep-UV resist

This paper present a methodology for modeling and simulating line-end shortening (LES) effects in deep-UV photoresist and calibrating the simulation with experimental data. A reaction/diffusion mode is first calibrated using large area dose-to-clear versus bake time data and thickness loss from a top-to-top bake experiment. SPLAT and STORM are linked to simulate the exposure and post exposure bake processes of chemically amplified resist. A threshold mode is then applied to determine the line-end shortening effects. Verification experiments were conducted on two resists, APEX-E and UVIIHS, for several types of geometric features, and the resist model parameters were fine tuned using the Method of Feasible Direction. The measurement of LES agrees quite well when the simulation using an exponential diffusion model of post exposure bake is used. The fine tuning reduced the RMS error to below the noise level in the experimental data and improve the accuracy in predicting LES to 10 percent of feature size.
Lithographic patterning of immobilized enzymes in chitosan thin films for multi-layer, chemical/biological sensors

Patterning of immobilized enzyme in spin-cast chitosan thin films will enable the creation of multi-layer biologically-active devices. Bulk immobilized enzymes used in multi-layer devices, in contrast to surface functionalized devices; enable the implementation and characterization of multi-component assays. This paper demonstrates a procedure to immobilize enzymes into an aqueous chitosan solution, spin-cast that solution into a thin-film, and, finally, pattern that thin film using photolithography and oxygen plasma. Enzymes immobilized, deposited, and patterned using this process retain functionality, as shown with the example assay of szlig-D-galactosidase (szlig-Gal) and fluorescein di-szlig-D-galactopyranoside (FDG), a fluorogenic substrate for szlig-Gal. Hydrogel thicknesses of 200 nm to 1.5 mum (dry) were achieved and line widths down to 2 mum were observed. Finally, a multi-layer stack of chitosan hydrogel is demonstrated using a stopping layer of sputtered silicon dioxide (SiO2).
Advanced Techniques to Increase the Number of Users and Bit Rate in OCDMA Networks

Optical code-division multiple-access (OCDMA) systems have recently become a topic of interest for their potential application in access points and optical LANs. In this paper, we review OCDMA systems and their limitations, as well as various experimental techniques to increase the number of users and/or bit rate in a system or a network. These techniques include incorporating M-ary modulation formats, hard-limiting receiver, variable thresholding, and orthogonal polarizations as the third dimension. We also discuss some network limitations such as congestion collapse and near-far effect, and we investigate two techniques to overcome them: interference avoidance and missing chip detection.
Decomposition based approach for synthesis of multi-level threshold logic circuits

Scaling is currently the most popular technique used to improve performance metrics of CMOS circuits. This cannot go on forever because the properties that are responsible for the functioning of MOSFETs no longer hold in nano dimensions. Recent research into nano devices has shown that nano devices can be an alternative to CMOS when scaling of CMOS becomes infeasible in the near future. This is motivating the need for stable and mature design automation techniques for threshold logic since it is the design abstraction used for most nano- devices. This paper presents a new decomposition theory that is based on the properties of threshold functions. The main contributions of this paper are: (1) A new method of algebraic factorization called the min-max factorization. (2) A decomposition theory that uses this new factorization to identify and characterize threshold functions. (3) A new threshold logic synthesis methodology that uses the decomposition theory. This synthesis methodology produces circuits that are better than the previous state of art (27% better gate count and comparable circuit depth).
Toward implementing distributed scaffolding: Helping students learn science from design

In this article, we present two studies that helped us understand the kinds of support that students need to learn science successfully from design activities. Both were enacted in the context of an approach to learning science from design called learning by design (LBD). In our first study, we designed and integrated a paper-and-pencil scaffolding tool, the design diary, into an LBD unit to support students' design-related activities. We learned two important lessons from the first study. First, we refined our understanding of the processes involved in designing and the ways we might present those processes to students. Second, and more important, we observed that in the dynamic, complex environment of the classroom, not all of the scaffolding could be provided with any one tool or agent. We found that students need multiple forms of support and multiple learning opportunities to learn science successfully from design activities. In our next study, we provided additional support through an organized system of tools and agents. Our analysis of data from the second study leads us to believe that supporting multiple students in a classroom requires us to rethink the notion of scaffolding as it applied to groups of learners in a classroom. We put forth the notion of distributed scaffolding as an approach to supporting hands-on inquiry learning in a classroom. © 2005 Wiley Periodicals, Inc. J Res Sci Teach 42: 185–217, 2005
X-ray crystallographic and solution state nuclear magnetic resonance spectroscopic investigations of NADP+ binding to ferredoxin NADP reductase from Pseudomonas aeruginosa.

The ferredoxin nicotinamide adenine dinucleotide phosphate reductase from Pseudomonas aeruginosa (pa-FPR) in complex with NADP+ has been characterized by X-ray crystallography and in solution by NMR spectroscopy. The structure of the complex revealed that pa-FPR harbors a preformed NADP+ binding pocket where the cofactor binds with minimal structural perturbation of the enzyme. These findings were complemented by obtaining sequential backbone resonance assignments of this 29518 kDa enzyme, which enabled the study of the pa-FPR−NADP complex by monitoring chemical shift perturbations induced by addition of NADP+ or the inhibitor adenine dinucleotide phosphate (ADP) to pa-FPR. The results are consistent with a preformed NADP+ binding site and also demonstrate that the pa-FPR−NADP complex is largely stabilized by interactions between the protein and the 2′-P AMP portion of the cofactor. Analysis of the crystal structure also shows a vast network of interactions between the two cofactors, FAD and NADP+, and th...
Judicial independence in transition: Revisiting the determinants of judicial activism in the constitutional courts of post-communist states

This study investigates the relationship between dimensions of judicial independence and judicial review in constitutional courts Central and Eastern Europe and the Former Soviet Union. In part a modified replication of prior works examining the issue, the study uses newly collected data from a panel of ten countries. It examines the relationship of judicial review with: (1) judicial independence (using both measures employed by the prior works, corrected versions of those measures, and measures original to this study); (2) political and social contextual factors; and (3) the receptiveness of post-communist countries to the importation of transplanted legal institutions. Improvements on the conceptualisation of judicial independence, inclusion of the dimensions of receptiveness, and a more appropriate panel of countries enable this study to present a more complete and accurate portrait of constitutional judicature in transition contexts. The results show that while corrections to prior measures of judicial independence improve the results at the margin, the entirely new measures of the concept represent a greater step forward. Several dimensions of judicial independence are positively related to judicial review, as are the measures of countries’ receptiveness to legal transplants. Other key factors positively related to judicial review in transition include legislative fragmentation at the time of each court decision, the scope of rights guarantees in a bill of rights, and popular trust in courts. Presidential power is negatively related to judicial review. The findings further indicate that aside from judicial independence, the prior works do present correct portrayals of most of the contextual influences they investigate.
Economic evaluation of capecitabine as adjuvant or metastatic therapy in colorectal cancer

Capecitabine, an oral prodrug of 5-fluorouracil, is indicated for adjuvant treatment in patients with Dukes' C colon cancer and for subsequent lines in metastatic colorectal cancer. The aim of this article is to review the literature on the economics of capecitabine for the treatment of colon cancer. A systematic review was conducted to search for articles published from January 2003 to December 2009 that met the inclusion criteria. For abstracts that were considered acceptable, full-text articles were then reviewed. Of the 42 potential studies that were identified, 13 original studies (16 publications) met the inclusion criteria. To date, the economic evaluation literature has consistently projected or found that capecitabine is not only a cost-effective treatment for adjuvant or for metastatic colorectal cancer (i.e., providing good value for money) but, furthermore, would actually be cost saving in the majority of country settings.
Classification of pediatric acute lymphoblastic leukemia by gene expression profiling

Contemporary treatment of pediatric acute lymphoblastic leukemia (ALL) requires the assignment of patients to specific risk groups. We have recently demonstrated that expression profiling of leukemic blasts can accurately identify the known prognostic subtypes of ALL, including T-cell lineage ALL (T-ALL), E2A-PBX1, TEL-AML1, MLL rearrangements, BCR-ABL, and hyperdiploid karyotypes with more than 50 chromosomes. As the next step toward developing this methodology into a frontline diagnostic tool, we have now analyzed leukemic blasts from 132 diagnostic samples using higher density oligonucleotide arrays that allow the interrogation of most of the identified genes in the human genome. Nearly 60% of the newly identified subtype discriminating genes are novel markers not identified in our previous study, and thus should provide new insights into the altered biology underlying these leukemias. Moreover, a proportion of the newly selected genes are highly ranked as class discriminators, and when incorporated into class-predicting algorithms resulted in an overall diagnostic accuracy of 97%. The performance of an array containing the identified discriminating genes should now be assessed in frontline clinical trials in order to determine the accuracy, practicality, and cost effectiveness of this methodology in the clinical setting.
Diagnostic evaluation of food-related allergic diseases

Food allergy is a serious and potentially life-threatening problem for an estimated 6% of children and 3.7% of adults. This review examines the diagnostic process that begins with a patient's history and physical examination. If the suspicion of IgE-mediated food allergy is compelling based on the history, skin and serology tests are routinely performed to provide confirmation for the presence of food-specific IgE antibody. In selected cases, a provocation challenge may be required as a definitive or gold standard reference test for confirmation of IgE mediated reactions to food. Variables that influence the accuracy of each of the diagnostic algorithm phases are discussed. The clinical significance of food allergen-specific IgE antibody cross-reactivity and IgE antibody epitope mapping of food allergens is overviewed. The advantages and limitations of the various diagnostic procedures are examined with an emphasis on future trends in technology and reagents.
Problem-Based Learning: Can It Improve Managerial Thinking?.

Problem-based learning (PBL), widely employed in medical schools, has much to offer management education as well. This article presents a comparative analysis of PBL’s likely benefits for medical a...
Prolonged Episodes of Persistent Asthma: A Distinct Clinical Pattern With Characteristic Clinical Features

Study objectives: To investigate a clinical pattern of unexplained persistent asthma that is episodic in nature and lasts for months to years. This pattern of prolonged episodes of unexplained, persistent asthma was not defined previously. Designs: Investigating the clinical features using a retrospective cohort design. Setting and patients: Eighteen subjects (ages, 13 to 64 years) from an allergy practice in a large prepaid health maintenance organization who had two or more prolonged episodes of unexplained persistent asthma lasting > 2 months during a 12-year period. Results: These subjects accounted for 39 asthmatic episodes lasting from 2 to 74 months (median, 7 months). The duration of the episodes positively correlates with the severity of asthma (p 5 0.02) at the initial part of the episodes. All episodes demonstrated a similar pattern, with symptom severity greatest at the onset and gradually diminishing until recovery. The relatively symptom-free intervals between the episodes ranged from 1.5 to 63 months (median, 13 months). Fifty-six percent of the episodes (95% confidence interval [CI], 40% to 72%) were associated with symptoms very suggestive or suggestive of an infection of the upper respiratory tract at the onset of the episodes; 33% of the episodes (95% CI, 19% to 50%) had possible symptoms suggestive of an infection; whereas only 10% of the episodes (95% CI, 3% to 24%) had questionable or no symptoms suggestive of an infection of the upper respiratory tract. Thirty-four episodes had the onset between September and March, whereas only 5 episodes occurred between April and August (p < 0.001). Conclusions: These observations indicate that prolonged episodes of unexplained, persistent asthma lasting for months to years constitute a distinct clinical pattern of asthma with characteristic clinical features. (CHEST 2000; 117:944 ‐949)