cssi/SciSciGPT-SciSciNet huggingface dataset:
New scaling laws predicting turbulent particle pair diffusion, overcoming the limitations of the prevalent Richardson-Obukhov theory

Both the evolution of particle pair separation distance l in a turbulent flow and how different length scales affect l are major unresolved challenges. The reigning theory in this topic is that of Richardson and Obukhov (R-O theory). We propose a new theory of pair diffusion in homogeneous, isotropic turbulence hypothesizing that not only structures of size l, but much larger ones also induce significant pair separation—ignored in the R-O theory. We arrive at new scaling laws for the pair diffusivity K, leading to K ∼ l γ where γ depends on the size of the inertial subrange: for a short inertial subrange, we find from our simulations that K ∼ l 1.44, and for an infinite inertial subrange, we find that K ∼ l 1.556—these relations agree closely with data. We assert that the celebrated “R-O constant” gl is neither physically meaningful nor a constant as universally assumed; our theory leads to two new physically relevant constants: GK for pair diffusivity and Gl for pair separation—which asymptote to G K ≈ 0.73 and G l ≈ 0.01 at high Reynolds numbers. We find that the particle dispersion is smaller by an order of magnitude compared to R-O prediction; this is significant in many applications such as sprays, and, in particular, the spread of biological contagions (e.g., COVID19) which persist longer and drift farther compared to R-O prediction. We find that the turbulent dispersion does not depend on the fine structure timescale—a striking result which would greatly facilitate turbulent diffusion modeling.
The Mobile Ummah: Belonging and Travel among Muslim Converts in Spain

Converts to Islam in southern Spain struggle to understand their place in the ummah (the global Muslim community). Some converts experience anxiety about their newfound minority Muslim status at ho...
Fresh and Hardened Behavior of UHPC Prepared with Different Mix Design Parameters

Ultra-high performance concrete (UHPC) is a new class of concrete that has superior workability, as well as mechanical and durability properties that far exceed those of conventional concrete. To achieve these properties, a very dense internal structure and the very low water-to-binder ratio (w/b) are generally necessary. While particle packing theories are typically used to design UHPC,due to the complexity of UHPC composition interaction and characteristics, the “theoretical optimum particle packing”might not necessarily provide the best UHPC performance. A comprehensive study of the impact of different design parameters such as types and amounts of supplemental cementitious materials (SCMs),binder content, and w/bare needed for a more rational design of UHPC. Besides, the extensive amount offine materials, together of the absense of coarse aggregate and the very low w/b often makes the mixing process of UHPC challenging. In this study, evaluations were performed with multiple series of mixtures prepared with different mix design parameters and considerations. In addition,this study included an evaluation of the impact of mixers on the fresh and hardened properties of UHPC.
Data Streaming Architecture for Visualizing Cryptocurrency Temporal Data

The utilization of data streaming is becoming essential in mobile computing applications to reduce latency and increase bandwidth. Vast amounts of data are generated continuously from the Web sites of stock markets and financial institutions. The data’s meta-analysis is critical for investors and needs to analyze in a short time. Traditionally, it requires several heterogeneous resources with high storage capacity to process and compute the data. Data streaming helps to capture, pipeline, and compute the data without storing it. This research aims to visualize the continuous updates to the cryptocurrency temporal data using aggregations and simple response functions. The cryptocurrency data is collected from multiple data sources. A macro-enabled Excel external live data from Web feature, C3.js, and Tableau tools are used to capture and pipeline the streamed data in real time to make better decisions. The results show that the visualizations are dynamically updating in the events of trades in cryptocurrencies over time. Data streaming researchers and practitioners benefit from extending the streaming architecture methodology and dataflow to other domains.
Proteomic Analysis During Pediatric Extracorporeal Membrane Oxygenation Reveals Modulation of Key Coagulation and Immune Process Proteins

Purpose Clinicians managing infants requiring extracorporeal membrane oxygenation (ECMO) are presented with unique challenges due to the intense inflammatory response and associated effects on coagulation. Plasma proteomics provides a global evaluation of proteins leading to identification of therapeutic targets. We used a highly multiplexed aptamer-based proteomic approach to identify changes in protein expression from plasma samples of children on ECMO. Methods All children requiring ECMO were …
Dying Empire: US Imperialism and Global Resistance

By the 1970s the global hegemony established by an American Empire in the post-World War II period faced increasing resistance abroad and contradictions at home. Contextualizing that hegemony, resistance and contradictions is the focus of Dying Empire. Presenting a wide-ranging synthesis of approaches, the book attempts to shed light on the construction of and challenges to the military, economic, and cultural imperial projects of the United States in the late 20th and early 21st centuries. Opposing US imperialism and global domination, Francis Shor combines academic and activist perspectives to analyze the crises endemic to empire and to propose a vision for the realization of another more socially just world. The text incorporates the most recent critical discussions of US imperialism and globalization from above and below to illuminate the practices and possibilities for global resistance. Offering insights into the political and cultural convulsions of recent decades whilst raising profound and compelling questions, this book will be of interest to activists, students, and scholars of American political culture, US foreign policy, globalization, imperialism, international relations, and social movements.
Effects of Flooding on Ion Exchange Rates in an Upper Mississippi River Floodplain Forest Impacted by Herbivory, Invasion, and Restoration

We examined effects of flooding on supply rates of 14 nutrients in floodplain areas invaded by Phalaris arundinacea (reed canarygrass), areas restored to young successional forests (browsed by white-tailed deer and unbrowsed), and remnant mature forests in the Upper Mississippi River floodplain. Plant Root Simulator ion-exchange probes were deployed for four separate 28-day periods. The first deployment occurred during flooded conditions, while the three subsequent deployments were conducted during progressively drier periods. Time after flooding corresponded with increases in NO3 −-N, K+ and Zn+2, decreases in H2PO4 −-P, Fe+3, Mn+2, and B(OH)4-B, a decrease followed by an increase in NH4 +-N, Ca+2, Mg+2 and Al+3, and an increase followed by a decrease for SO4 −2-S. Plant community type had weak to no effects on nutrient supply rates compared to the stronger effects of flooding duration. Our results suggest that seasonal dynamics in floodplain nutrient availability are similarly driven by flood pulses in different community types. However, reed canarygrass invasion has potential to increase availability of some nutrients, while restoration of forest cover may promote recovery of nutrient availability to that observed in reference mature forests.
Computer Simulation of Prenucleation Cluster Using Tercolation Theory 1

Publisher Summary Metropolis presented the first application of Monte Carlo method to statistical mechanics. Lee applied the procedure to simulate the structure of physical clusters. As noted by Haile, this is typically done using a fixed number of molecules N, contained in fixed volume V, and maintained at constant temperature T. Haile also alludes to methods, which are a blend of stochastic (Monte Carlo) and deterministic (molecular dynamics) methods. This chapter describes “percolation theory,” which is employed to simulate potentially irregular growth of prenucleation clusters, which are more close to the reality of random movements of gas molecules. For practical reasons, the molecules are chosen to be hard spheres. To initiate a cluster growth, a molecule is chosen for the start of the chain. A second molecule is then attached to the surface of the first. The attachment, if necessary, may be forced to give a specific structure, if the phase change is from gas to solid phase, such as the formation of computer chips, for example in a cubic lattice, or the attachment is accomplished in accordance with satisfaction of a prescribed distribution function. In typical phase reference, the molecules will approach this embryonic center from all directions. However, only those molecules would stick that approach from a feasible direction and are not too energetic.
Stress responses in alfalfa (Medicago sativa L). XVII: Identification of multiple hydrolases and molecular characterization of an acidic glucanase

Multiple chitinases and glucanases were identified in extracts from fungal infected alfalfa tissues by chromatofocusing, activity gel assays and Western blotting. At least six glucanase isoforms were detected by activity staining of isoelectric focusing gels, varying in apparent pI from 4·7 to approximately 10·0. Chitinases were purified from alfalfa extracts by affinity chromatography; several chitinases in alfalfa extracts cross-reacted on Western blots with anti-chitinase antibody prepared against a basic bean chitinase. Thus, both chitinase and glucanase families appear to be complex in alfalfa. A cDNA for an acidic glucanase Aglu1, with a deduced pI of around 6·0, was isolated from a library prepared from RNA from elicited alfalfa suspension cells. This glucanase, which possesses a putative glycosylated C-terminal extension, appears to belong to a small gene family in alfalfa. It is not strongly expressed in alfalfa plants infected with Colletotrichum trifolii (Race 1). Glucanase transcripts detected by the Aglu1 probe were expressed at low levels in control, uninfected alfalfa plants, and were strongly induced in Phoma medicaginis infected leaf tissue and elicited cell suspension cultures.
Pedestal-free transform-limited femtosecond pulse generation at 10 GHz using a polarization maintaining dispersion decreasing fiber and dispersion imbalanced nonlinear loop mirror

We report a polarization maintaining version of a pulse compressor based on a dispersion decreasing fiber (DDF) and a dispersion-imbalanced nonlinear optical loop mirror (DI-NOLM). The pulses at the DDF output are as short as 43 fs. Using post amplification at the DI-NOLM output, we obtained a 170 fs pedestal-free pulse train at an average power of 100 mW and a repetition rate of 10 GHz.
Sailing against the Wind: African Americans and Women in U.S. Education

Sailing against the Wind: African Americans and Women in U.S. Education. Kofi Lomotey. Albany: State University of New York Press, 1997. 186 pp.
Optimal-complexity direct solver based fast synthesis of the physical layout of electromagnetic structures

A linear (optimal) complexity direct solver not only can significantly accelerate the forward analysis of electromagnetic problems, but also open up a new solution space for fast inverse design (synthesis). In this work, we show how the layout synthesis of electromagnetic structures can be transformed to an equivalent inverse problem, and subsequently solved by a linear-complexity direct finite-element solver without the need for an optimizer.
Pipes, pools, and filters: How collaboration networks affect innovative performance

Research summary: Innovation requires inventors to have both new knowledge and the ability to combine and configure knowledge (i.e., combinatory knowledge), and such knowledge may flow through networks. We argue that both combinatory knowledge and new knowledge are accessed through collaboration networks, but that inventors' abilities to access such knowledge depends on its location in the network. Combinatory knowledge transfers from direct contacts, but not easily from indirect contacts. In contrast, new knowledge transfers from both direct and indirect contacts, but is far more likely to be new and useful when it comes from indirect contacts. Exploring knowledge flows in 69,476 patents and 89,930 unique inventors reveals evidence that combinatory knowledge from direct contacts and new knowledge from indirect contacts significantly affects innovative performance. Managerial summary: Inventors often combine ideas to create innovations. To do this, they need ideas to combine and they need the ability to combine those ideas. Inventors can get ideas to combine as well as the ability to combine ideas through prior co-workers. Prior co-workers can share ideas that may be relevant for the inventor's project and can tell the inventor about other things that other people are working on, especially people the inventor may not know. This can help inventors easily learn about ideas from friends-of-friends. The ability to combine ideas, however, is much harder to pass on. Prior co-workers must carefully work with the inventor to teach him or her the complex processes of combining ideas. This means that it is very hard to learn how to combine knowledge from a friend-of-a-friend, but it may be possible to learn from prior co-workers. We explore this phenomenon in the social relationships of software inventors. Copyright © 2015 John Wiley & Sons, Ltd.
Hemodynamics and low density lipoprotein metabolism. Rates of low density lipoprotein incorporation and degradation along medial and lateral walls of the rabbit aorto-iliac bifurcation

We have investigated whether arterial wall low density lipoprotein (LDL) metabolism in areas of disturbed flow differs from the metabolism in adjacent regions of undisturbed flow. Using the rabbit aorto-iliac bifurcation as a model, we examined the rates of LDL incorporation and catabolism in vivo and correlated them to the arterial flow patterns in these regions. The trapped ligand method was used to quantitate the rates of LDL incorporation and degradation over a 20-hour period in three hemodynamic zones of the daughter iliac branch: 1) a region of flow separation where the shearing forces are elevated along the medial wall and reduced along the lateral wall, 2) a transition region where the flow patterns begin to approach the fully established situation, and 3) a unidirectional flow region with symmetric fluid shearing forces along the medial and lateral walls. Our results indicate an elevated rate of LDL incorporation into the lateral versus the medial wall in the proximal zone of flow separation (5.2 +/- 0.8 nl/mg/hr vs. 3.7 +/- 0.5 nl/mg/hr, p less than 0.01). A similar elevation in the degradation rate of the lateral over the medial wall of this most proximal zone was also observed (2.1 +/- 0.4 vs. 1.4 +/- 0.2, p less than 0.05). No such differences were observed regarding LDL incorporation and degradation in the transitional or unidirectional hemodynamic zones. These results suggest that modifications in arterial wall LDL incorporation and catabolism are induced by hemodynamic forces. The implications of these findings for the formation of the atherosclerotic lesion are discussed.
Combining Independent Syntactic and Semantic Annotation Schemes

We present MAIS, a UIMA-based environment for combining information from various annotated resources. Each resource contains one mode of linguistic annotation and remains independent from the other resources. Interactions between annotations are defined based on use cases.
Evaluation of Heated Frying Oils Containing Added Fatty Acids

Frying oils (corn, lightly and highly hydrogenated soybean and tallow) were heated 24 hr at 200°C and acid value and percentage polar compounds measured. Fatty acids (stearic, oleic and linoleic) were added to the oils at 1 and 5% levels to determine their effect on oil quality. Corn oil formed acidic and polar compounds at faster rates than the other oils. With 5% fatty acids added, acid value decreased because acidic compounds evaporated faster than they were formed. Polar compound formation generally increased with fatty acid addition in corn oil and lightly hydrogenated soybean oil and decreased in highly hydrogenated soybean oil and tallow.
Development of a Fatigue Life Assessment Tool for Pipelines With Local Wrinkling Through Physical Testing and Numerical Modelling

Pipelines are one of the primary modes to transport hydrocarbon products throughout the world. A majority of these pipeline systems are buried, which are susceptible to ground movement that imposes axial forces and bending moments on the pipeline section. As a result of these forces and moments pipeline section may experience localized deformation that result in wrinkling, buckling and other damage mechanisms. This may impair the pipeline mechanical performance with respect to local stress concentration, lower strength and reduced fatigue life. Cyclic operational loads or ground movement events may result in strain reversals within the pipeline section that may lead to fracture through low cycle fatigue process.In this study, physical testing was conducted to examine the strength and fatigue life performance characteristics of hot rolled steel (44-W). The effects of the test sample bend radius, wall thickness and imposed displacement stroke range on fatigue performance were examined. The data was used to develop and refine continuum finite element modeling procedures that can be used to assess the influence of pipeline damage on fatigue life in a more detailed numerical simulation framework.Copyright © 2014 by ASME
Plasma exchange versus intravenous immunoglobulin treatment in myasthenic crisis

Article abstract We performed a retrospective multicenter chart review to compare the efficacy and tolerance of plasma exchange (PE) and intravenous immunoglobulin (IVIg) in treatment of 54 episodes of myasthenic crisis. After adjustment for other variables, PE (compared with IVIg) was associated with a superior ventilatory status at 2 weeks (partial F = 6.2, p = 0.02) and 1 month functional outcome (partial F = 4.5, p = 0.04). However, the complication rate was higher with PE compared with IVIg (13 versus 5 episodes, p = 0.07).
Estimating Long-Term Ground Level Concentrations of SO2 from Short-Term Peak Data

Maximum concentrations of sulfur dioxide vary approximately inversely as the square root of the averaging time for periods up to a year, a much longer time period than those reported in previously published studies. This finding is based on analyses of SO2 and tracer gas concentrations measured in the vicinities of a test stack, a petrochemical complex, and eight power plants. Therefore, for a given set of emission conditions, long-term concentrations of SO2 and other conservative pollutants emitted by well-defined sources can be rapidly estimated from maximum short-term concentrations, and vice versa. The scatter in the data corresponds to an estimation error of about a factor of three for averaging time conversions of one day to one year. This is approximately the same error associated with conventional calculations. Therefore, the use of averaging time conversions is justified as a rapid screening technique to estimate compliance with ambient air quality standards.
Optogenetic GABAA Receptors: Controlling Neural Inhibition with Light

GABAA receptors are the major mediators of inhibitory neurotransmission in the mammalian brain. GABAergic transmission is highly heterogeneous in vivo due to the diverse receptor subunit composition and localization. To better elucidate the roles of different GABAA receptors in the neural signaling network, it is desirable to develop tools to modulate the activity of a specific subtype of GABAA receptors. Optogenetic control of protein functions has been an emerging approach for studying cell signaling. Here we present a novel approach for modulating GABAA-receptor activities. The approach involves two players: (1) an engineered GABAA receptor with a cysteine properly positioned near the GABA binding site; and (2) a photoswitch that can be covalently attached to the designated cysteine. The photoswitch consists of a cysteine-reactive maleimide, a photosensitive azobenzene, and an antagonist of the receptor. Receptor inhibition is turned on and off upon light switching.Several candidate mutants and photoswitches were identified from an extensive screening on recombinant GABAA receptors (α1β2 and α5β2) using electrophysiology. The “optogenetic receptors” (i.e., the photoswitch-labeled mutants) exert rapid, reversible changes in the amplitude of GABA-evoked currents in response to light switching. When the attached photoswitch is converted to the trans state by 500-nm light, the receptor becomes less sensitive to GABA (manifested in an increased EC50) compared to the unlabeled receptor. The activity of the inhibited receptor is restored upon 380-nm illumination. These optogenetic GABAA receptors are potentially useful tools for studying synaptic and extrasynaptic GABAergic transmission in the mammalian brain.
Electron beam control using experimentally measured transport matrices

Free electron lasers (FELs) place very stringent requirements on the quality of electron beams. Present techniques for commissioning and operating electron accelerators may not be optimized to produce the high brightness beams needed. Therefore, it is proposed to minimize the beamline errors in electron accelerator transport systems by minimizing the deviations between the experimentally measured and design transport matrices of each beamline section. The transport matrix for each section is measured using evoked responses. In addition, the transverse phase space of the beam is reconstructed by measuring the spatial distribution of the electrons at a number of different betatron phases and applying tomographic techniques developed for medical imaging.
How accurate is ultrasonography in detecting hydronephrosis in azotemic patients

Screening for hydronephrosis continues to be an essential part of the evaluation of patients with azotemia of unknown cause. To determine whether sonography is as reliable as nephrotomography for screening purposes, we carried out a prospective, comparative study. Sixty-two patients were evaluated. Mean serum creatinine was 4.3 mg/dl. Of 116 kidneys, 45 were obstructed according to urographic criteria and 42 of these were correctly called hydronephrotic by sonography. The 3 false negative sonographic studies occurred in 2 patients. All 3 kidneys contained radiopaque calculi visible on the plain abdominal film. Of the 71 nonobstructed kidneys, 5 were mistakenly called hydronephrotic by ultrasound, giving a false positive rate of 7%. We believe it is appropriate to use gray-scale ultrasound as a screening test for urinary obstruction in azotemic patients providing the plain abdominal radiograph shows no calcifications.
Measurement of instabilities and ion heating in an electron beam ion source

Abstract The role of instabilities in the performance of an electron beam ion source (EBIS) has been studied experimentally. Measurements were made on the EBIS test stand at the Lawrence Berkeley Laboratory using an rf spectrum analyzer, an X-ray camera and a time-of-flight analyzer. Instabilities associated with the beam current, trapped electrons and trapped ions were identified. It was found that when the instabilities were present the effective ionization rate was reduced the radial extent of the ions was increased. These observations are consistent with the hypothesis that the ions are being heated by the instabilities.
Esophagopericardial fistula arising from barrett's esophagus

Esophagopericardial fistula is a rare complication of numerous benign, malignant, and traumatic conditions of the esophagus. Approximately 100 cases of fistulae between the esophagus and heart have been reported. We describe the second reported case of an esophagopericardial fistula secondary to a benign esophageal ulcer within Barrett's mucosa without prior surgery. The radiologic, endoscopic, and surgical management of this case are discussed.
Procreative Liberty, Enhancement and Commodification in the Human Cloning Debate

The aim of this paper is to scrutinize a contemporary standoff in the American debate over the moral permissibility of human reproductive cloning in its prospective use as a eugenic enhancement technology. I shall argue that there is some significant and under-appreciated common ground between the defenders and opponents of human cloning. Champions of the moral and legal permissibility of cloning support the technology based on the right to procreative liberty provided it were to become as safe as in vitro fertilization and that it be used only by adults who seek to rear their clone children. However, even champions of procreative liberty oppose the commodification of cloned embryos, and, by extension, the resulting commodification of the cloned children who would be produced via such embryos. I suggest that a Kantian moral argument against the use of cloning as an enhancement technology can be shown to be already implicitly accepted to some extent by champions of procreative liberty on the matter of commodification of cloned embryos. It is in this argument against commodification that the most vocal critics of cloning such as Leon Kass and defenders of cloning such as John Robertson can find greater common ground. Thus, I endeavor to advance the debate by revealing a greater degree of moral agreement on some fundamental premises than hitherto recognized.
Linear dependencies in fourth-rank turbulence tensor models☆

Abstract In turbulence modeling, and perhaps elsewhere, one encounters the need to model a fourth-rank tensor M ijpq , which is symmetric in ij and pq, in terms of a second-rank symmetric tensor b ij . It has commonly been assumed that there are fifteen linearly independent tensor forms in the most general such model. Here we show that there are only twelve, and give the three linear dependencies.
Macrophyte root and rhizome decay: the impact of nutrient enrichment and the use of live versus dead tissue in decomposition studies

The decomposition of roots and rhizomes of two macrophytes, Eleocharis cellulosa and Typha domingensis, was studied in oligotrophic phosphorus (P) limited marshes of northern Belize. The experiment was conducted in long-term control and P enriched plots in five limestone-based inland marshes. Decomposition of naturally senescent root and rhizome litter was studied over 9 months using litterbags. Belowground litter was acquired by growing plants in unenriched (control) or P enriched marsh soils for 5 months. Plants were then allowed to naturally senesce using a split root design, which promoted nutrient retranslocation. The resulting senescent litter had 30 % higher C:P and 40 % lower P content than living roots and rhizomes. There were no differences in C:N among treatments or senescent versus live litter. Litterbags, filled with control or enriched root and rhizome litter, were buried in the upper 10–14 cm soil in the corresponding plot of each marsh. Differences in the rate of decay between species were greatest for rhizome tissue, with Typha decaying more than twice as fast as Eleocharis. For both species, however, tissue P enrichment had no effect on coarse root and rhizome decay. Enhanced root production from P enrichment, coupled with no change in decay, should lead to enhanced accretion over time. Additional tests, using litterbags filled with living roots and rhizomes, yielded dramatically different results between treatments compared to senescent tissue. Results from senescent belowground tissue also differed from shoot decomposition. Caution should be exercised when inferring belowground decomposition from live tissue and aboveground rates of decay.
GAUGE: Grid Automation and Generative Environment

The Grid has proven to be a successful paradigm for distributed computing. However, constructing applications that exploit all the benefits that the Grid offers is still not optimal for both inexperienced and experienced users. Recent approaches to solving this problem employ a high-level abstract layer to ease the construction of applications for different Grid environments. These approaches help facilitate construction of Grid applications, but they are still tied to specific programming languages or platforms. A new approach is presented in this paper that uses concepts of domain-specific modeling (DSM) to build a high-level abstract layer. With this DSM-based abstract layer, the users are able to create Grid applications without knowledge of specific programming languages or being bound to specific Grid platforms. An additional benefit of DSM provides the capability to generate software artifacts for various Grid environments. This paper presents the Grid Automation and Generative Environment (GAUGE). The goal of GAUGE is to automate the generation of Grid applications to allow inexperienced users to exploit the Grid fully. At the same time, GAUGE provides an open framework in which experienced users can build upon and extend to tailor their applications to particular Grid environments or specific platforms. GAUGE employs domain-specific modeling techniques to accomplish this challenging task. Copyright © 2005 John Wiley & Sons, Ltd.
Use of Self-perspectives and their Sources to Predict the Mathematics Enrollment Intentions of Girls and Boys

An understanding of the differences in the ways in which self-efficacy and interest influence boys’ and girls’ intentions to continue enrollment in mathematics courses may provide insight into how to encourage continued mathematics enrollment for all students. Two competing theoretical models of mathematics self-efficacy and interest in predicting students’ enrollment intentions and achievement were evaluated separately across samples of middle level boys and girls. One model was empirically supported for both groups and indicated the independent influence of self-efficacy and interest in predicting enrollment intentions. Multi-group analyses revealed that self-efficacy’s influence in enrollment intentions and achievement was significantly stronger for boys than for girls, and interest was significantly more important in the prediction of enrollment intentions for girls than for boys.
Influence of the temperature-ramp on mass transfer effects during temperature-programmed desorption from porous catalysts

The influence of mass transfer effects on temperature-programmed desorption (TPD) spectra from porous catalysts has been examined from the standpoints of nondimensional analysis and numerical simulation of specific models. Considerable attention has been focused on the interaction of H/sub 2/ and CO over Group VIII metal supported catalysts. In the absence of mass transfer limitations and under conditions of equilibrium adsorption, reasonably accurate estimates of the enthalpy of adsorption can be obtained using a theoretical relationship, which is independent of the transport model used to describe flow through the porous bed of catalyst. Gorte has proposed that intraparticle concentration gradients can be minimized by reducing catalyst particle size and carrier gas flow rate. This criterion was obtained by nondimensionalization of the differential equations governing mass transfer during TPD and appears to provide a suitable basis for predicting the onset of intraparticle mass transfer effects. This work assumes that this condition is met and considers the applicability of a convenient procedure that has been proposed for mathematically simulating thermal desorption from porous adsorbent particles. This method is an alternative to the dispersion model and introduces the concept of a mixing cell. In such a model, the number of mixing cells inmore » a cascade of mixing cells is chosen such that axial dispersion of gas-phase species is accurately described: as axial dispersion becomes more significant, the number of mixing cells that simulate this dispersion decreases. 13 references.« less
In Vivo Biochemistry in Bacterial Cells Using FRAP: Insight into the Translation Cycle

In vivo measurements of the mobility and binding kinetics of cellular components are essential to fully understand the biochemical processes occurring inside cells. Here, we describe a fluorescence recovery after photobleaching-based method that can be easily implemented to the study of reaction-diffusion processes in live bacteria despite their small size. We apply this method to provide new, to our knowledge, quantitative insight into multiple aspects of the bacterial translation cycle by measuring the binding kinetics and the micrometer-scale diffusive properties of the 50S ribosomal subunit in live Caulobacter cells. From our measurements, we infer that 70% of 50S subunits are engaged in translation and display, on average, limited motion on the micrometer scale, consistent with little mixing of transcripts undergoing translation. We also extract the average rate constants for the binding of 50S subunits to 30S initiation complexes during initiation and for their release from mRNAs when translation is completed. From this, we estimate the average time of protein synthesis and the average search time of 50S subunits before they engage in the next initiation event. Additionally, our experiments suggest that so-called free 50S subunits do not diffuse freely; instead their mobility is significantly slowed down, possibly through transient associations with mRNA.
Mice bred for severity of acute alcohol withdrawal respond differently in a Go/No-go task

Background Mice selectively bred for high or low withdrawal to acute alcohol differ on a number of traits, including consumption of alcohol, conditioned place preference for alcohol, and sensitivity to alcohol-induced locomotor activity. One trait that has not been examined in these mice is behavioral inhibition. Methods High and low alcohol withdrawal mice (second replicate: high and low acute alcohol withdrawal [HAW-2/LAW-2]) were trained and tested in a Go/No-go task. Mice were administered 0.0, 0.5, 1.0, and 1.5 g/kg ethanol (EtOH) on 3 occasions according to an incomplete Latin Square. A separate cohort of C57BL/6J (B6) and DBA/2J (D2) mice (the progenitor strains for HAW-2/LAW-2 mice) underwent the same protocol, using the same EtOH doses. Results HAW-2 and LAW-2 mice did not differ in behavioral inhibition at baseline, although LAW-2 mice did have higher overall levels of responding in the task. EtOH did not alter behavioral inhibition in these mice. However, it did decrease responses to the Go cue, and this effect was greater in HAW-2 mice than in LAW-2 mice. D2 mice had lower behavioral inhibition than B6 mice at baseline, and EtOH slightly decreased behavioral inhibition in both strains. Conclusions The findings with D2 and B6 mice generally fit with the existing literature. However, the lack of a difference in behavioral inhibition between HAW-2 and LAW-2 mice was unexpected, as well as the absence of any effect of these doses of EtOH on behavioral inhibition in these mice. Nonetheless, the findings do suggest that selectively breeding for high or low withdrawal to acute alcohol can lead to differences in operant behavior in the Go/No-go task.
Six Persistent Research Misconceptions

Scientific knowledge changes rapidly, but the concepts and methods of the conduct of research change more slowly. To stimulate discussion of outmoded thinking regarding the conduct of research, I list six misconceptions about research that persist long after their flaws have become apparent. The misconceptions are: 1) There is a hierarchy of study designs; randomized trials provide the greatest validity, followed by cohort studies, with case–control studies being least reliable. 2) An essential element for valid generalization is that the study subjects constitute a representative sample of a target population. 3) If a term that denotes the product of two factors in a regression model is not statistically significant, then there is no biologic interaction between those factors. 4) When categorizing a continuous variable, a reasonable scheme for choosing category cut-points is to use percentile-defined boundaries, such as quartiles or quintiles of the distribution. 5) One should always report P values or confidence intervals that have been adjusted for multiple comparisons. 6) Significance testing is useful and important for the interpretation of data. These misconceptions have been perpetuated in journals, classrooms and textbooks. They persist because they represent intellectual shortcuts that avoid more thoughtful approaches to research problems. I hope that calling attention to these misconceptions will spark the debates needed to shelve these outmoded ideas for good.
RENAL FUNCTION AS A MARKER OF HUMAN FETAL MATURATION

Sixty clinically well infants of various gestational ages (27 to 40 weeks) were studied from 24-40 hours after birth to evaluate glomerular filtration rate and renal excretion rate of sodium at various stages of fetal maturation. Creatinine clearance was directly related to gestational as (r = 0.643). Fractional sodium excretion was inversely related to gestational age (r = -0.755). The renal functions of small for gestational age infants were similar to those of full-term infants whose birth weights were appropriate for gestational age. The data showed that the glomerular functions of an infant below 32 weeks of gestation were more predominant than the tubular function resulting in a greater fractional sodium excretion rate and higher urinary Na loss in infants of this gestational age, when compared with the more mature infants.
FOS expression induced by an ethanol-paired conditioned stimulus.

To identify brain areas involved in ethanol-induced Pavlovian conditioning, brains of male DBA/2J mice were immunohistochemically analyzed for FOS expression after exposure to a conditioned stimulus (CS) previously paired with ethanol (2 g/kg) in two experiments. Mice were trained with a procedure that normally produces place preference (Before: ethanol before the CS) or one that normally produces place aversion (After: ethanol after the CS). Control groups received unpaired ethanol injections in the home cage (Delay) or saline only (Naive). On the test day, mice were exposed to the 5-min CS 90 min before sacrifice. Before groups showed a conditioned increase in activity, whereas the After group showed a conditioned decrease in activity. FOS expression after a drug-free CS exposure was significantly higher in Before-group mice than in control mice in the bed nucleus of the stria terminalis (Experiment 1) and anterior ventral tegmental area (Experiments 1-2). Conditioned FOS responses were also seen in areas of the extended amygdala and hippocampus (Experiment 2). However, no conditioned FOS changes were seen in any brain area examined in After-group mice. Overall, these data suggest an important role for the mesolimbic dopamine pathway, extended amygdala and hippocampus in ethanol-induced conditioning.
Barriers to entry and competitive strategies

The relationships between the difficulty of entry and competitive strategies in five industries, chosen for their differing structural contexts, were tested. Statistical support was found for the value of pre-entry analysis of entry barriers and of firms' predicted responses to potential entry. In particular, the creation of idle productive capacity appears to be a potent deterrent to new entrants.
Titanium oxide aerogels prepared from titanium metal and hydrogen peroxide

Abstract The reaction of hydrogen peroxide with excess titanium metal produces rigid titanium oxide aquagels. Subsequent solvent exchanges with ethanol and carbon dioxide, and supercritical drying produces the corresponding aerogels. The aerogels are translucent yellow in appearance, are amorphous to X-rays, and have a BET surface area of 350 m 2 /g. The empirical formula of the material, as prepared, is TiO 3 H 2.7 C 0.35 . Infrared spectroscopy indicates the presence of peroxide and carbonate groups. The microstructure of the aerogel consists of a network of elongated particles 2–5 nm in diameter and tens of nm in length. Thermal treatment under argon at 473 K causes rapid decomposition of the aerogel, forming a blue-gray powder consisting of a mixture of rutile and anatase with a surface area of 80 m 2 /g. Additional thermal treatment at 973 K under air forms predominantly rutile, with a surface area of 20 m 2 /g.
Recovery of an interface from boundary measurement in an elliptic differential equation

We study the inverse problem of recovering an interior interface from a boundary measurement in an elliptic boundary value problem arising from a semiconductor transistor model. We set up a nonlinear least-squares formulation for solving the inverse problem, and establish the necessary derivatives with respect to the interface. We then propose both the Gauss---Newton iterative method and the conjugate gradient method for the least-squares problem, and present implementation of these methods using integral equations.
Laser Raman spectra of bis(2,4-pentanedionato)dimethyltin(IV) in oriented single crystals and solutions: the molecular structure in solution

Abstract In a study of the structure of (CH 3 ) 2 Sn(acac) 2 (Hacac = acetylacetone), Raman spectra have been recorded with benzene solutions, non-oriented crystalline samples, and with oriented single crystals. Far infrared spectra also are reported for non-oriented samples. Factor group analyses in C 2h 5 symmetry are carried out for the skeletal and ligand vibrations. The crystal spectra are assigned in terms of the factor group species and in most cases also in terms of the symmetry species of the molecular modes. The frequencies of the skeletal vibrations are almost identical for the crystal where (CH 3 ) 2 Sn(acac) 2 exists as a centrosymmetric molecule with trans methyl groups and the benzene solution. Intermolecular interactions between the two molecules in the unit cell are very weak as correlation splittings must be less than 1 cm −1 . Relative values were determined for the Raman crystal tensor components of the symmetric (SnC 2 ) stretching mode from single crystal intensity measurements. By appropriate transformation, these were used to obtain the relative values of the molecular tensor for this mode. From these data, the depolarization ratio for a non-oriented sample was computed to be p = 0.19 ± 0.02, p s = 0.10 ± 0.02. With the benzene solution, the observed values were 0.18 ± 0.02, 0.11 ± 0.01. The relative values of the components of the derived polarizability tensor are similar to those of (CH 3 ) 2 SnF 2 which also has trans methyl groups. Using the Wolkenstein approximation of bond polarizabilities, it is estimated that the decrease in anisotropy brought about by a trans to cis isomerization upon dissolution should cause a decrease in p of 38 per cent, in marked contrast to the experimental results. Both the frequency and intensity data suggest that (CH 3 ) 2 Sn(acac) 2 has the same trans structure in solution and in the crystal, although the cis structure has been assigned to the molecule in solution on the basis of dipole moment data. Possible origins of the reported orientation dipole moment of 2.95 D for the molecule in benzene solution are discussed.
Solder Joint Reliability Prediction of Flip Chip Packages Under Shock Loading Environment

Solder joint reliability under shock loading condition has been a concern over the years especially with constant reductions in the characteristic dimensions of the package and the solder joint. With the impeding transition to lead free solder, attention has moved from temperature cycle failure to mechanical shock failure. A method has been developed that employs a specially designed shock test board (STB) to characterize the solder joint performance as a function of board surface strain. This unique test board can be adapted to a wide range of test and boundary conditions. Using this board, a range of shock inputs is tested to establish correlation of the dynamic response and solder joint damage severity. The effects of package size, board thickness, and solder ball pitch are included in this paper to highlight the critical design factors for solder joint reliability in shock. This method can be used to characterize solder joint performance at the component level, early in development. One can also provide board strain based design limits guide system design and prevent late discovery of solder joint issues. Modal analysis based finite element models have been used to supplement understanding of the board response. The model demonstrates good correlation of the strain on the board and the stresses developed in the solder joint. The modeling data also suggested that the maximum principal stress at the solder joint face is a good failure criterion as it maps well with the actual failure locus found.Copyright © 2005 by ASME
Operant conditioning in mice

Abstract Only in recent years has the necessity to test drugs and chemicals for behavioral toxicity been recognized. The mouse is the animal most commonly used for conventional toxicity screening, but it has rarely been used for toxicity studies using operant behavior. This investigation demonstrates that the mouse has a potential similar to that of the rat to learn operant tasks if lever press is substituted by lever touch and if the caloric value of reinforcement pellets is diluted by noncaloric bulk. Under these conditions mice can learn the following schedules of reinforcement: continuous, discriminated variable-interval, discriminated single alternation go, no-go, and differential reinforcement of low rate (DRL). As in rats, performance is optimal within a range of 20±5 per cent weight reduction from the body weight under ad libitum feeding conditions.
Interplay between mycoplasmas and host target cells

The infectious pattern of mycoplasmas (Mycoplasma penetrans, Mycoplasma pneumoniae and Mycoplasma genitalium) in mammalian cells was examined using confocal microscopy and flow cytometry combined with cell fractionation and mycoplasma viability determinations. Within 2 h postinfection mycoplasmas parasitize cell surfaces, enter the intracellular spaces and locate throughout the cytoplasmic and perinuclear regions. These mycoplasmas can be cultivated from cytoplasmic and nuclear fractions 96 h later and continue to persist intracellularly for at least 7 days, suggesting a much more active intracellular role for mycoplasmas than had been considered previously.