cssi/SciSciGPT-SciSciNet huggingface dataset:
Verified query results from hybrid authentication trees

We address the problem of verifying the accuracy of query results provided by an untrusted third party Publisher on behalf of a trusted data Owner. We propose a flexible database verification structure, the Hybrid Authentication Tree (HAT), based on fast cryptographic hashing and careful use of a more expensive one-way accumulator. This eliminates the dependence on tree height of earlier Merkle tree based proposals and improves on the VB tree, a recent proposal to reduce proof sizes, by eliminating a trust assumption and reliance on signatures. An evaluation of the Hybrid Authentication Tree against the VB tree and Authentic Publication showing that a HAT provides the smallest proofs and faster verification than the VB tree. With moderate bandwidth limitations, the HATs low proof overhead reduces transfer time to significantly outweigh the faster verification time of Authentic Publication. A HAT supports two verification modes that can vary per query and per Client to match Client resources and applications. This flexibility allows the HAT to match the best performance of both hash based and accumulator based methods.
Vibrational spectra of ammonia chemisorbed on platinum (111) . II. The electron scattering mechanism

Abstract We have measured the angle and energy dependence of the inelastic cross sections for NH3 chemisorbed on Pt(111). The relative contributions of dipole and nondipole processes in the on-specular intensities were determined. The angular dependence (off-specular scattering) was found to be more useful than the impact energy dependence for discrimination between the two scattering mechanisms. For both molecular states of NH3/Pt(111), strong impact scattering contributions were found in the NH stretching mode intensities. One particular mode, the degenerate stretch [νd(NH)] was selectively excited by impact scattering. The energy dependence showed an enhancement of all of the inelastic intensities at low impact energies (1 eV). This enhancement was found to be a result of a surface reflectivity increase, coupled with an increase in the inelastic cross section. The latter increase is not predicted by dipole theory. Determination of the molecular orientation was not possible, due to the complex contributions of dipole and impact scattering.
Environmental performance rating and disclosure : an empirical investigation of China's green watch program

Environmental performance rating and disclosure has emerged as an alternative or complementary approach to conventional pollution regulation, especially in developing countries. However, little systematic research has been conducted on the effectiveness of this emerging policy instrument. This paper investigates the impact of a Chinese performance rating and disclosure program, Green Watch, which has been operating for 10 years. To assess the impact of Green Watch, the authors use panel data on pollution emissions from rated and unrated firms, before and after implementation of the program. Controlling for the characteristics of firms and locations, time trend, and initial level of environmental performance, the analysis finds that firms covered by Green Watch improve their environmental performance more than non-covered firms. Bad performers improve more than good performers, and moderately non-compliant firms improve more than firms that are significantly out of compliance. The reasons for these different responses seem to be that the strengths of incentives that the disclosure program provides to the polluters at different levels of compliance are different and the abatement costs of achieving desired levels of ratings are different for different firms.
Isolation and characterization of a recombinant heat shock protein of Aspergillus fumigatus.

Abstract Background: Aspergillus fumigatus, a common environmental fungus, is responsible for a number of lung disorders, including allergy and infection, in human beings. For immunodiagnosis of these diseases, standardized, pure, and relevant antigens are not currently available. Methods: A complementary DNA library of A. fumigatus was constructed with messenger RNA isolated from 96-hour-old culture of the organism. Fusion proteins expressed with the cDNA were characterized and evaluated. Results: One of the clones, which reacted with both rabbit anti-A. fumigatus serum and a pool of sera from patients with allergic bronchopulmonary aspergillosis, expressed a 65 kd protein of A. fumigatus. The recombinant protein reacted with immunoglobulin E and immunoglobulin G antibodies in the sera from patients with allergic bronchopulmonary aspergillosis. The deduced amino acid sequence of the partially sequenced complementary DNA of the clone is homologous with the hsp 90 family of heat shock proteins in human beings and other organisms. Conclusion: The immunodominant nature and the homology to human heat shock proteins suggest a possible role for this protein in protective immunity and autoimmunity.
Online tools for accessing veterinary information : Electronic continuing resources

Abstract This article presents an overview of veterinary medical library Web sites as “one-stop-shops” for accessing quality, authoritative information related to veterinary medicine. Highlighted are some of the features and easy-to-use resources that can be found within these sites, including a brief discussion of electronic journals. Also featured is a list of veterinary medical libraries, and a list of veterinary gateways, reference works, professional organizations, networks and services, government, pet care and health, and miscellaneous categories that are freely available from U.S. and Canadian libraries serving veterinary colleges.
Clues To The Formation And Evolution Of Tidal Dwarf Galaxies

Galaxy-galaxy interactions and mergers can cause major perturbations to the structure and content of galaxies. One of the interesting aspects of these interactions is the possible formation of dwarf galaxies in/from the tidal debris. The idea that such self-gravitating objects could form from gravitational encounters was first suggested by Zwicky (1956, Ergebnisse der Exakten Naturwissenchaften 29, 344). We present high sensitivity HI observations, taken with the VLA, as a part of a multiwavelength study of interacting galaxies to look for evidence of these objects. Seven Arp galaxies were observed and we present a preliminary analysis for five of these. Although our data needs further editing to fully remove the effects of solar contamination and continuum emission, preliminary results for these five systems indicate various levels of disturbance in the HI. Arp 31 shows very low levels of disturbance, with extended HI arms, one of which extends in the same direction as its companion NGC 694. Arp 135 is a very disturbed system with a prominent HI tail and various concentrations of HI located both in the tail and in the vicinity of the system. Gravitational and stability tests need to be performed on these knots to see if they qualify as tidal dwarfs. Arp 78, though a very complex and disturbed system, has no obvious tidal dwarf candidates, despite the presence of some clumping. Arp 213 is not particularly disturbed, although its isovelocity contours are complex. This could be indicative of a warp or the effects of a major-minor merger. We have, so far, not detected any candidates to qualify as tidal dwarfs. Arp 158 appears to be an intermediate stage merger with distinct nuclei embedded within both the optical and the HI nuclei. The data for this system was particularly plagued by the effects of solar interference and continuum emission. Much further editing is required for this system before we can make any conclusive remarks about the presence or absence of clumps. M. Iyer acknowledges an International Travel Grant from the A.A.S.
Archival Preservation Practice in a Nationwide Context.

The preservation of historical materials, in a variety of forms and formats, is both a cultural necessity and a central responsibility for professional archivists. Archivists need to define for themselves just what archival preservation entails and assess the capacity of the thousands of archives, large and small, scattered and isolated from each other, to develop and administer sophisticated preservation programs. The author presents the results of the first nationwide study of archival preservation practices in the United States. He describes a model of archival preservation that partially shaped the research project, summarizes the research process involved, reports the major findings, and discusses the implications of the research for archivists and the archival profession.
Symmetry-breaking bifurcation of analytic solutions to free boundary problems: An application to a model of tumor growth

In this paper we develop a general technique for establishing analyticity of solutions of partial differential equations which depend on a parameter e. The technique is worked out primarily for a free boundary problem describing a model of a stationary tumor. We prove the existence of infinitely many branches of symmetry-breaking solutions which bifurcate from any given radially symmetric steady state; these asymmetric solutions are analytic jointly in the spatial variables and in e. 1. THE MODEL AND MAIN RESULT In this paper we present a general technique for establishing analyticity of solutions of systems of partial differential equations which depend analytically on a parameter e. The method works not only for boundary value problems but also for free boundary problems. In this latter context it can be used to establish long time existence of transient solutions, and also to study the existence of spatially asymmetric steady solutions. Since free boundary problems are typically more challenging than their boundary-value counterparts, we shall concentrate here on a free boundary problem from developmental biology, namely, a model of tumor growth. To further exemplify the generality of our approach an instance of a boundary value problem (in a fixed domain) is presented in the last section of the paper. A variety of other problems are amenable to the same analysis, including, in particular, the Hele-Shaw model of fluid flow [11]. Within the last several decades a number of mathematical models have been developed that aimed at describing the evolution of carcinomas (see. e.g., [1, 5, 6, 8, 12, 13] and the references cited there). The main objective of these models has been to qualitatively describe, under various simplifying assumptions, the growth and stability of tumor tissue. Analysis and simulations of such models are helping to assess the relative importance of various mechanisms affecting tumor growth as well as the efficacy of certain cancer treatments. On the other hand, the description of the stationary (dormant) configurations that arise from the models has only been addressed in the case of spherical tumors, but otherwise it remains largely unexplored. In this paper we develop a method for establishing analyticity of Received by the editors August 17, 1999. 1991 Mathematics Subject Classification. Primary 35B32, 35R35; Secondary 35B30, 35B60, 35C10, 35J85, 35Q80, 92C15, 95C15.
Simple Technical Trading Strategies: Returns, Risk and Size

This paper investigates the efficacy of the most simple and commonly used technical trading strategies seen across firms of varying market capitalization. The results show that the success of trading strategies declines sharply with an increase in firm size, supporting the hypothesis that technical analysis is most appropriate for smaller stocks. Technical strategies applied to smaller stocks earn excess average monthly returns of 1.7%, even after adjusting for aggregate risk factors such as market, size, book-to-market, momentum, and liquidity. In contrast, when applied to large stocks, such strategies do not earn excess returns over a buy and hold strategy. The results are robust when adjusted for time varying expected returns, transactions costs, and nonsynchronous trading.
Reducing Fertilizer-Nitrogen Losses from Rowcrop Landscapes: Insights and Implications from a Spatially Explicit Watershed Model†

We present conceptual and quantitative models that predict changes in fertilizer-derived nitrogen delivery from rowcrop landscapes caused by agricultural conservation efforts implemented to reduce nutrient inputs and transport and increase nutrient retention in the landscape. To evaluate the relative importance of changes in the sources, transport, and sinks of fertilizer-derived nitrogen across a region, we use the spatially explicit SPAtially Referenced Regression On Watershed attributes watershed model to map the distribution, at the small watershed scale within the Upper Mississippi-Ohio River Basin (UMORB), of: (1) fertilizer inputs; (2) nutrient attenuation during delivery of those inputs to the UMORB outlet; and (3) nitrogen export from the UMORB outlet. Comparing these spatial distributions suggests that the amount of fertilizer input and degree of nutrient attenuation are both important in determining the extent of nitrogen export. From a management perspective, this means that agricultural conservation efforts to reduce nitrogen export would benefit by: (1) expanding their focus to include activities that restore and enhance nutrient processing in these highly altered landscapes; and (2) targeting specific types of best management practices to watersheds where they will be most valuable. Doing so successfully may result in a shift in current approaches to conservation planning, outreach, and funding.
Stability of wheat proteins in solution

Gluten from defatted wheat flour was used to study the stability of protein extracts during various steps that are routinely made in protein analyses. These included aqueous extraction and short-term storage, handling of chromatographic fractions, freeze-drying and reconstitution. Protein composition was monitored by size-exclusion high performance liquid chromatography (SE-HPLC) and sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Distilled, deionized and sterilized water were used to prepare the gluten solutions (TFA or HCl solutions at pH 3.0) and to prepare elution solvents. In distilled or deionized water there was a decrease of polymeric protein and a corresponding increase in the monomeric components with time unless initial heating was applied. Protein extracts obtained from gluten and solvents prepared with freshly sterilized water showed no change during storage for 4 days at a temperature of 25 °C. Microbiological assays of the water samples supported the view that microbial contaminants were the source of proteases. After elution from SE-HPLC column with acetonitrile/water followed by freeze-drying and re-dissolution, the SE-HPLC profile of the monomeric proteins was unchanged. However, polymeric proteins aggregated, lost solubility and showed an altered SE-HPLC profile. The effect appeared to be due to the presence of acetonitrile and could be avoided by membrane concentration instead of freeze-drying.
Automated access to a large medical dictionary: online assistance for research and application in natural language processing

Online dictionaries can be important tools for research and application in natural language processing. This paper describes work with a machine-readable version of "Dorland's Illustrated Medical Dictionary". First the characteristics of the dictionary are briefly described, and then the complex process of converting the tape to an online interactive dictionary is discussed. The results of several experiments in automatically deriving information from the online dictionary are presented, and the paper ends with a discussion of the use of the online dictionary as a tool in the development of a natural language processing system designed for the biomedical domain.
Definitions and Eligibility Criteria Applied to the Adolescent and Adult Population with Learning Disabilities across Agencies

The purpose of this study was to investigate the similarities and differences across state agencies serving ado- lescents and adults with learning disabilities in relation to their definitions and eligibility criteria for services. Significant differences were noted within and across agen- cies. Specific emphasis was given to investigating the 51 state departments of special education (SPE) and vocational reha- bilitation (VR), including Washington, DC. A conceptual framework consisting of 21 components was used in analyz- ing the definitions and criteria. A follow-up phone interview was conducted with 14 state departments of SPE and VR to provide additional input on current trends that might not have been reflected in the empirical data. An outcome of those findings resulted in suggestions for definitions and eli- gibility criteria policy across state agencies.
Large scale yielding in blister specimens

Nonlinear von Karman plate theory was used for a consistent analysis of pressurized circular, island and peninsula blister specimens. The configurations that were considered ranged from linear plates to membranes. Interfacial energy release rates and fracture mode-mixes were extracted from the solutions. For a given pressure and all possible materials and delamination length to thickness (aspect, a/h) ratios, the peninsula blister provided the highest energy release rate, followed by the island and circular blisters. The extent of yielding in delaminating copper films with a range of thicknesses and an interfacial toughness of 100 J/m2 was then examined. It was found that all configurations of the circular blister suffered from large scale yielding. The stress levels in the island blister were notably lower, especially for a/h=10, where yielding only occurred over about 10 percent of the delaminating copper layer. While extensive yielding was still present in peninsula blister configurations with a/h=100 and 500, there was none for a/h=10. A scheme for extending the utility of blister specimens to higher aspect ratios was suggested and analyzed.
Vibrational Excitations in Single Trimetal-Molecule Transistors

Single-molecule transistors incorporating trimetal molecules of Cu3(dpa)4Cl2 and Ni3(dpa)4Cl2 (dpa = 2,2‘-dipyridylamide) have been fabricated. Conductance is measured as a function of bias and gate voltages at low temperature, showing single-electron tunneling behavior through the molecules. Additional structures corresponding to the excitations in the molecules are observed, which can be attributed to intramolecular vibrational excitations coupled to the electron tunneling processes. The energies of the vibrational states are dependent on the redox state of the included molecules.
Kinetic Evidence for Incorrectly Folded Intermediate States in the Refolding of Denatured Proteins

Kinetic studies of the denaturation and renaturation of proteins indicate metastable intermediates which are not on the direct pathway between native and denatured states. This suggests that the initial steps in the folding of a structureless polypeptide chain may often be rapidly reversed and without influence on the ultimate result.
Analysis of meiotic prophase I in live mouse spermatocytes

Events occurring during meiotic prophase I are critical for the successful production of haploid gametes. Many prophase I events are mediated by a meiosis-specific structure called the synaptonemal complex. To date, the limited knowledge we have about the dynamics of these prophase I events in mice comes from fixed, two-dimensional preparations of meiotic cells making it impossible to study the three-dimensional (3D) arrangement of meiotic chromosomes. The current study involves the development of an imaging system to view prophase I events in live mammalian spermatocytes by generating a transgenic mouse, Sycp3–Eyfp21HC, expressing a fluorescently tagged synaptonemal complex protein, SYCP3. Using this live imaging system, the 3D structural arrangement of chromosomes in the different prophase I substages has been characterized in live spermatocytes, and aspects of the 3D architecture of spermatocytes have been observed that would not be possible with existing techniques. Additionally, chromosome movement in prophase I spermatocytes and meiotic progression from pachynema to diplonema were observed following treatment with the phosphatase inhibitor, okadaic acid (OA), which accelerates the progression of cells through late prophase I. These studies demonstrate that the Sycp3–Eyfp21HC live imaging system is a useful tool for the study of mammalian prophase I dynamics.
Activation of the Transcription Factor Nuclear Factor-Kappa B in Uterine Luminal Epithelial Cells by Interleukin-1 Beta 2: A Novel Interleukin-1 Expressed by the Elongating Pig Conceptus

Conceptus mortality is greatest in mammals during the peri-implantation period, a time when conceptuses appose and attach to the uterine surface epithelium while releasing proinflammatory molecules. Interleukin 1 beta (IL1B), a master proinflammatory cytokine, is released by the primate, rodent, and pig blastocyst during the peri-implantation period and is believed to be essential for establishment of pregnancy. The gene encoding IL1B has duplicated in the pig, resulting in a novel gene. Preliminary observations indicate that the novel IL1B is specifically expressed by pig conceptuses during the peri-implantation period. To verify this, IL1B was cloned from mRNA isolated from Day 12 pig conceptuses and compared with IL1B cloned from mRNA isolated from pig peripheral blood leukocytes (PBLs). The pig conceptuses, but not the PBLs, expressed a novel IL1B, referred to here as interleukin 1 beta 2 (IL1B2). Porcine endometrium was treated with recombinant porcine interleukin 1 beta 1 (IL1B1), the prototypical cytokine, and IL1B2 proteins. Immunohistochemistry and real-time RT-PCR were used to measure activation of nuclear factor-kappa B (NFKB) and NFKB-regulated transcripts, respectively, within the endometrium. Both IL1B1 and IL1B2 activated NFKB in the uterine luminal epithelium within 4 h. The NFKB activation and related gene expression, however, were lower in endometrium treated with IL1B2, suggesting that the conceptus-derived cytokine may have reduced activity within the uterus. In conclusion, the peri-implantation pig conceptus expresses a novel IL1B that can activate NFKB within the uterine surface epithelium, likely creating a proinflammatory microenvironment during establishment of pregnancy in the pig.
Indochinese Immigrant Children: Problems in Psychiatric Diagnosis

Twenty-one Indochinese refugee children and adolescents were evaluated and treated in a child psychiatry clinic. Work was done in conjunction with bilingual counselors, who were familiar with the patients' families and culture. Cross-cultural child rearing differences and the experience of recovering from severe stress confounded the application of DSM-III diagnoses. The revision of the diagnoses is described and the implications for the limitations for present diagnostic models are briefly explored.
The binary self-dual codes of length up to 32: a revised enumeration

Abstract This paper presents a revised enumeration of the binary self-dual codes of length up to 32 given by Conway and Pless in 1978–1980. The list of 85 doubly-even self-dual codes of length 32 is essentially correct, but several of their descriptions need amending. The principal change is that there are 731 (not 664) inequivalent self-dual codes of length 30. Furthermore, there are three (not two) [28, 14, 6] and 13 (not eight) [30, 15, 6] self-dual codes. Some additional information is provided about the self-dual codes of length less than 32.
The Role of Teacher Stance When Infusing Inquiry Questioning Into Middle School Science Classrooms

The purpose of this study was to describe how a teacher's stance of wonder, curiosity, and exploration during the use of hypothetical inquiry situations served as a way for the teacher to address her goals for students to be more vocal members of the learning community; to encourage critical and creative thinking in the students; to provide them with meaningful, context-rich opportunities for synthesizing personal past experience with ongoing classroom instruction; to enhance socialization skills in the middle school environment; and to provide an improvisational atmosphere for both learning and teaching.
Reply to B. E. lapointe and P. J. Barile (2004). Comment on J. C. Zieman, J. W. Fourqurean, and T. A. Frankovich. Seagrass Die-Off in Florida Bay: Long-term trends in abundance and growth of turtle grass,Thalassia testudinum. 1999. Estuaries 22: 460–470

The Lapointe and Barile (2004) note claims to be a comment on our recent paper in Estuaries (Zieman et al. 1999), but it is really both a comment and a statement of a hypothesis. As a comment on our paper, it demonstrates a skewed reading and direct contradiction of the stated conclusions of our paper. As a statement of a new hypothesis, it relies on a very selective re-analysis of previously published work while ignoring completely the published results of the original authors. "Getting the science correct" is indeed important, owing to the large commitment of Federal and state funds to address problems of the entire south Florida ecosystem that have been caused by a century of human activities. Lapointe and Barile unfortunately have contributed no new information on the state of Florida Bay and in their comment rely on facile reinterpretation of fragments of a very robust data set that many scientists have collected over the past two decades. In this reply, we will address issues raised in roughly the same order that they appear in their comment. Beginning in 1987, dense meadows of Thalassia testudinum in Florida Bay began a rapid and as yet poorly understood die-off (Robblee et al. 1991). The first contention of Lapointe and Barile is that Zieman et al. (1999, p. 467) "overstated the role
Magnetic properties of the alkanediammonium copper halides

Abstract Powder magnetic susceptibility and magnetization data have been obtained for the remaining, unreported members of the quasi-two-dimensional series [NH 3 (CH 2 ) n NH 3 ] CuX 4 for n =2−10 and X=Cl and Br. Values for J (in-plane), J ′ (out-of-plane) and T c are tabulated for the entire series. An alternation between ferromagnetic and antiferromagnetic behavior for the low temperature phases in the bromine series was found. Several unusual low temperature phases which could not be classified were also seen.
Alkaline phosphatase of Drosophila melanogaster. II. Biochemical comparison among four allelic forms.

Biochemical analyses of partially purified preparations of APH-4 and -6 (common allelic forms) and APH-2 and -10 (rare allelic forms) of D. melanogaster reveal that the two common forms are similar in all properties investigated except for pH optimum (8.0 vs. 8.5). The common and rare forms share certain properties in common but differ in that the common forms are more stable to heat and more sensitive to inhibition by inorganic phosphate. With respect to such properties as substrate preferences and Ki values for inorganic phosphate, the common forms and APH-2 are similar to one another, whereas APH-10 is distinctly different. All four activities show preference for a phosphoaromatic compound as substrate, with O-phosphotyrosine being the best substrate of biological origin. Transphosphorylation, as related to these allelic forms of APH, is discussed.
Development of ultra-low magnetic field sensors with magnetic tunneling junctions

The discovery of tunneling magnetoresistance (TMR) has enhanced the magnetoresistance (MR) ratio from the giant magnetoresistance (GMR) regime of around 10% to over 400% at room temperature. A combination of magnetic tunnel junctions with high magnetoresistance ratio and soft magnetic layers enables the development of ultra-low magnetic field sensor with sensitivity down to the scale of picoTesla. A magnetic field sensor with such high sensitivity would have important applications in biomedicine, information storage, and remote sensing such as higher resolution images for cardiograph and magnetic resonance imaging and thus earlier detection of abnormal health condition; higher hard-disk density; and remote sensing of metallic objects. We have constructed an automated four-probe electrical measurement system for measuring TMR of magnetic tunnel junctions with high throughput, enabling us to optimize the properties of the devices. Magnetron sputtering is used to deposit thin films with thickness ranged from angstroms to nanometers. Photolithography and ion plasma etching are applied to pattern the devices. The devices have a range of size from 10 μm x 10 μm to 80 μm x 80 μm. The device is composed of the bottom electrode, free soft magnetic layer, insulating oxide layer, pinned layer, pinning layer, and top electrode. The magnetization of the free layer can be rotated by the external magnetic field which in turn changes the resistance of the device and provide the sensing capability. The system structure, design consideration, fabrication process, and preliminary experimental results are discussed and presented in this paper.
Decomposition and inversion of von Neumann-like convolution operators

Methods are presented for the decomposition of two-dimensional von Neumann-like convolution operators into sums and products of smaller von Neumann-like operators. Consequences of the techniques include the face that ever second-order operator is the sum and product of five or fewer first-order operators. A totally symmetric second-order operator can be written as the sum and product of three or fewer first-order operators. In general, an nth-order von Neumann-like operator can always be written as the sum and product of three lower order operators. The following inversion result is also discussed. If the (circulant) von Neumann mean filter operator is defined on a square coordinate set with n rows and n columns, then it fails to be invertible only if either the integer 5 divides n or the integer 6 divides n. This result provides a partial solution to a question posed by P. Gader.© (1991) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Traditional and transgenic strategies for controlling tomato-infecting begomoviruses

Viruses of to the family Geminiviridae are considered some of the most important pathogens in tropical and subtropical regions of the world. Members of one Geminiviridae genus, Begomovirus, have been causing severe losses, particularly in tomato (Lycopersicon esculentum) production in the Americas and the Caribbean. Several new begomoviruses have been reported in the region and, at least one, Tomato yellow leaf curl virus (TYLCV), has been brought in from the Old World via infected transplants. In addition, the recombination events that are playing an important role in Begomovirus diversity have increased the complexity of their control. This scenario has led to the search for control measures that go beyond traditional host genetic resistance, chemical controls and cultural practices. In this review, besides the recommended classical control measures, transgenic approaches will be discussed, as well as the mechanisms involved in their successful control of viruses.
Sample-size salience and statistical inference

In this study, students were asked to judge which of two samples was most likely to produce data exceeding the population mean. In two experiments, we examined the importance of the discriminability of the sample sizes for students’ judgments. The findings conflict with claims that students make their judgments based on a representativeness heuristic and support the view that errors reflect inattention to important but nonsalient dimensions of the task.
Probing Frozen Molecular Embraces

The interaction of a catalyst with its substrate partner can coax the reactant into a new conformation that can stretch its bonds and rotate its functional groups. These changes can reduce the energetic costs of reaction and facilitate a specific approach for other reactants that favors a particular stereochemical product. Some of the new catalysts being developed demonstrate exquisite control even over the way that bulky substituents are assembled on a framework by trapping them in a stereochemical configuration from which they cannot be disengaged, thus avoiding unwanted rearrangements ( 1 , 2 ). Some of these catalysts clasp onto one of the reactants through multiple hydrogen-bonding (H-bonding) attachment points that complement those on the substrate, working cooperatively to produce the desired configuration in the binding partner ( 1 , 2 ). On page 694 of this issue, Garand et al. ( 3 ) submit a complex formed by a peptide-derived catalyst (C) and an aromatic substrate (S) (see the figure) to a detailed structural interrogation through a combination of mass spectrometry and infrared (IR) spectroscopy.
CaM Induced Gating Mechanism of AQP0

Aquaporin 0 (AQP0) is a water channel protein necessary for lens transparency. AQP0 water permeability is lower than that of other aquaporins, and is regulated by calcium through the action of calmodulin (CaM). NMR studies indicate that one CaM monomer interacts with the C-terminal α-helices of two adjacent AQP0 monomers residing in an AQP0 tetramer. Our goal is to determine the mechanism by which CaM gates AQP0 water permeability. We utilize molecular dynamics simulations of a model of the AQP0-CaM complex. Trajectories of AQP0 and the AQP0-CaM complex embedded in a POPC lipid bilayer show differences between the water occupancy of the AQP0 pore with and without bound CaM. The motion of tyrosine 149 (Y149), a residue residing in the ‘phenolic barrier’ of AQP0, is reduced in the AQP0-CaM complex. Hypotheses concerning the gating mechanism of AQP0 are tested utilizing the Xenopus oocyte-swelling assay. Specifically, Y149 mutants are tested for calcium regulation. Analysis of the interface between AQP0 and CaM shows a chain of interacting residues connecting the interface and Tyr149. Analysis of our simulations indicates that Tyr149 serves as the gate in the regulation of AQP0 water permeability by CaM. Under conditions of low CaM binding, Tyr149 moves dynamically into and out of the AQP0 pore with a low open (out-of-pore) probability. Upon CaM binding, the motion of Tyr149 is decreased and the open probability is reduced. These results reveal a novel gating mechanism in which the binding of a protein to AQP0 reduces the dynamics of pore lining residues, thereby reducing the open-probability of the pore.
The Role of Ortho-Substitution in the Synthetic Auxins.

The structure of molecules active as auxins has been investigated extensively, and presents one of the most attractive of all problems of the relation between a chemical structure and a biological activity. The structures are. relatively simple, the compounds generally stable and the tests reproducible and quantitative. The results and conclusions to date were reviewed in 1949 (13). The general rules for the structural requirements of active molecules which were given more than 14 years ago (5) have been slightly modified and restated to fit certain new cases (16, 17), but basically new departures in principle have not appeared until quite recently. There are now, however, two important new points to consider. One of these is the proposal of Muir and co-workers (3, 9, 10) that in order for a substance to liave auxin activity, at least one of. the positions on the aromatic ring ortho to the acidic side chain must be unsubstituted. This proposal stemmed from the inactivity (or very low activity) of 2,4,6-trimethylphenylbutyric acid, 4,7-dichloro-2-methylindoleacetic acid, and particularly the 2,4,6-trichloro-, tribromoand trimethyl-derivatives of phenoxyacetic acid. These authors used the elongation of Avena coleoptile sections as a test. It has been pointed out earlier (15) that the Avena coleoptile is more selective than the pea stem. However, the present paper shows that also in pea stems these latter three compounds are of very low activity. The second new principle is the activity of certain benzoic acid derivatives, reported (1) and confirmed (10) for growth of Avena sections, and which is also confirmed herein for the pea test. Earlier suggestions of activity in this series, based on different tests, had been made for 2-bromo-3nitrobenzoic acid and some other derivatives (19) ; but activity in the pea test had not been found (18). It was suggested that these compounds did not have true auxin activity (18). The fact that true auxin activity is present in benzoic acid derivatives means that the rule that the acid group must be separated from the ring by at least one atom (5), though valid in the large majority of cases (13), is subject to important exceptions. The same is true for the suggested explanation of this requirement, namely that the acid group must be held out of the plane of the ring (16). In the present study a number of other compounds relating to the above two points have been tested, and it is shown that the role of ortho-substitution is less simple than it appeared at first. Some of the facts are consistent
Report of Workshop 5: Early high-dose chemotherapy

Summary Workshop 5, entitled "Early High-Dose Chemotherapy for Hodgkin's Lymphoma', was conducted at the Third International Symposium on Hodgkin's Lymphoma in Koln, Germany, on September 23, 1995. The objective of the workshop was to determine whether one could identify, at diagnosis, a high-risk group of Hodgkin's disease patients who could be subjected to high-dose therapy with acceptable toxicity as part of their initial therapy. D. Hasenclever of Leipzig, Germany, presented a preliminary analysis of a multivariate model which involved over 4000 patients with advanced Hodgkin's disease. Unfortunately, the model did not permit the definition of a significant group of patients with less than a 50% progression free survival at 5 years. A. Carella from Genoa, Italy, and S. J. Proctor from Newcastleupon-Tyne, U.K., presented their ongoing randomized trials of early high-dose therapy while N. Schmitz from Kiel, Germany, presented the results of a matched pair analysis of patients receiving high-dose chemotherapy compared to patients receiving conventional chemotherapy. A. H. Goldstone from London, United Kingdom, and J. O. Armitage from Omaha, USA., presented important long-term toxicity data. C. Gisselbrecht from Paris, France, presented the data on second neoplasms. D. L. Longo from Frederick, USA., focused on the results of using either conventional or highdose therapy as salvage therapy, hi summary the workshop defined both the enthusiasm for improving the treatment results of patients with advanced Hodgkin's disease by using high-dose therapy and the problems associated with conducting those type of studies. The following is a report on Workshop 5, 'Early HighDose Chemotherapy for Hodgkin's Lymphoma', which was conducted at the Third International Symposium on Hodgkin's Lymphoma in Koln, Germany, on September 23,1995. The objective of the workshop was to determine whether one could identify, at diagnosis, a high-risk group of Hodgkin's disease patients who could be subjected to high-dose therapy with acceptable toxicity as part of their initial therapy. Therefore, the workshop focused on several questions. First, can one define at diagnosis a group of patients with less than a 50% risk of freedom from relapse at 5 years? Second, what is the existing preliminary data that suggests that early high-dose therapy can improve the therapeutic results? Third, what is the expected acute and long-term toxicity of early high-dose therapy? Fourth, what are the results of alternative treatment strategies that use either conventional or high-dose therapy as salvage therapy? Finally, can one now design a rational strategy for early high-dose chemotherapy in Hodgkin's disease? Regarding the initial question of defining at diagnosis a group of patients with less than a 50% risk of freedom from relapse at 5 years, D. Hasenclever of Leipzig, Germany, presented a preliminary analysis
A Formal, Bayesian Approach for Uncertainty Analysis of a Watershed Model

Uncertainty analysis (UA) has received substantial attention in water resources during the last decade. Bayesian approaches are often preferred for UA. This study describes a formal Bayesian approach for the assessment of parameter uncertainty and predictive uncertainty using a spatially distributed hydrologic model and will demonstrate its application using data from a well monitored experimental watershed. A Markov-Chain Monte Carlo (MCMC) scheme has been used to sample posterior parameter distributions. A formal, flexible likelihood function that explicitly accounts for heteroscedasticity, temporal correlation and non-normality of simulation residuals has been used to describe closeness of the simulated and observed streamflow. Performance of the formal likelihood function will be compared to that of simple least squares with regard to generating accurate predictive uncertainty estimates at multiple streamflow gaging stations available in the experimental watershed. Limitation of the SLS assumptions with regard to the structure of model residuals will be illustrated and capability of the formal likelihood function to address these assumptions will be scrutinized. Finally, the maximum likelihood solutions identified by the uncertainty analysis method will be compared to the optimal solutions determined using a single objective optimization exercise to test effectiveness of the uncertainty analysis method to also identify the optimal solutions sought during model calibration.
Hybrid modeling of DFIGs for wind energy conversion systems

Abstract The synchronous reference frame is widely used in Doubly Fed Induction Generation (DFIG) modeling. In a DFIG, it is usually assumed that slip control is in place at the rotor-side converters to make sure that the injected rotor voltage at slip frequency gives a constant stator frequency (60 Hz or 50 Hz). In the analysis, the injected rotor voltages are directly expressed in the synchronous reference frame. In the cases where slip control is not available, the above modeling will not work. This paper implements a hybrid model (dqabc) of a DFIG. The key modeling idea is to use the frequencies of the injected rotor voltages as explicit inputs and further transform the injected rotor voltage into the synchronous reference frame. This allows one to model and simulate scenarios including: (i) acceleration via rotor injection, (ii) harmonic simulation for six-pulse rotor injection, and (iii) negative sequence compensation using rotor injection. Matlab/Simulink is used to perform the simulations of three cases listed above. Laboratory experiments on two of the cases confirm the validity of the model and simulation results.
Raynaud’s phenomenon and digital ischemia: a practical approach to risk stratification, diagnosis and management

Digital ischemia is a painful and often disfiguring event. Such an ischemic event often leads to tissue loss and can significantly affect the patient's quality of life. Digital ischemia can be secondary to a vasculopathy, vasculitis, embolic disease, trauma, or extrinsic vascular compression. It is an especially serious complication in patients with scleroderma. Risk stratification of patients with scleroderma at risk for digital ischemia is now possible with clinical assessment and autoantibody profiles. Because there are a variety of conditions that lead to digital ischemia, it is important to understand the pathophysiology underlying each ischemic presentation in order to target therapy appropriately. Significant progress has been made in the last two decades in defining the pathophysiological processes leading to digital ischemia in rheumatic diseases. In this article we review the risk stratification, diagnosis, and management of patients with digital ischemia and provide a practical approach to therapy, particularly in scleroderma.
Effects of hydrologic and water quality drivers on periphyton dynamics in the southern Everglades

Everglades periphyton mats are tightly-coupled autotrophic (algae and cyanobacteria) and heterotrophic (eubacteria, fungi and microinvertebrates) microbial assemblages. We investigated the effect of water column total phosphorus and nitrogen concentrations, water depth and hydroperiod on periphyton of net production, respiration, nutrient content, and biomass. Our study sites were located along four transects that extended southward with freshwater sheetflow through sawgrass-dominated marsh. The water source for two of the transects were canal-driven and anchored at canal inputs. The two other transects were rain-driven (ombrotrophic) and began in sawgrass-dominated marsh. Periphyton dynamics were examined for upstream and downstream effects within and across the four transects. Although all study sites were characterized as short hydroperiod and phosphorus-limited oligotrophic, they represent gradients of hydrologic regime, water source and water quality of the southern Everglades. Average periphyton net production of 1.08 mg C AFDW−1 h−1 and periphyton whole system respiration of 0.38 mg C AFDW−1 h−1 rates were net autotrophic. Biomass was generally highest at ombrotrophic sites and sites downstream of canal inputs. Mean biomass over all our study sites was high, 1517.30 g AFDW m−2. Periphyton was phosphorus-limited. Average periphyton total phosphorus content was 137.15 μg P g−1 and average periphyton total N:P ratio was 192:1. Periphyton N:P was a sensitive indicator of water source. Even at extremely low mean water total phosphorus concentrations ( ≤ 0.21 μmol l−1), we found canal source effects on periphyton dynamics at sites adjacent to canal inputs, but not downstream of inflows. These canal source effects were most pronounced at the onset of wet season with initial rewetting. Spatial and temporal variability in periphyton dynamics could not solely be ascribed to water quality, but was often associated with both hydrology and water source.
Sequential chromatogram ratio technique: evaluation of the effects of retention time precision, adsorption isotherm linearity, and detector linearity on qualitative and quantitative analysis

A study of the sequential chromatogram ration technique was done to characterized and correct for retention time variation, peak-shape change due to concentraions exceeding the adsorption isotherm linear range, and mild detector nonlinearty over a broad concentration range. A sensitive minimization routine was developed to overlay chromatographic peaks from sequential injections using a simple displacement along the time axis
Comments on diffusive and electrostatic effects with immobilized enzymes

Abstract Shuler, Aris & Tsuchiya (1972) have recently considered the combined effects of diffusive resistance and electrostatic field on the rate of reaction catalyzed by an enzyme immobilized on a non-porous surface. They employed a potential distribution for the electrical double layer which is asymptotically valid when surface potential is small.The complete Gouy-Chapman solution, which is valid for higher surface potential, is employed here. Numerical values of the effectiveness factor calculated with this potential distribution agree very closely with the results of Shuler et al. for most cases. It is shown that the effectiveness factor can (i) attain magnitudes much greater than unity in physically realizable systems, (ii) approach the solution for “infinite” surface potential at reasonable values of surface charge density, and (iii) pass through a maximum as bulk substrate concentration is varied. This behavior leads to the existence of an optimum surface concentration for enzyme immobilized on a highly charged non-porous support such that the most effective catalytic action on a charged substrate is ensured. Finally, it is established that significant electrical and/or diffusive effects result in non-linear Lineweaver-Burk plots of reciprocal observed reaction velocity against reciprocal bulk substrate concentration. These non-linear plots cannot be interpreted in the same way as linear plots obtained when enzyme is unbound.