nils-herrmann/clean_scirepeval huggingface dataset:
Spatial Order in Fluvial Systems: Horton's Laws Derived from Mixed Hexagonal Hierarchies of Drainage Basin Areas

The number of stream basin areas (that is, the number of Strahler stream segments) is predicted on the basis of an hexagonal model for basin areas. It is suggested that the number of orders and the number of basins per order balance opposing tendencies for minimum overland work for streams flowing in small basins and maximum work savings in large, as opposed to small, channels. In addition, the entropy of the system approaches the maximum possible. The model agrees with empirical data in cases where the land surface is reasonably uniform with regard to structure and lithology. The necessity for approximate geometric progressions of basin areas with order creates geometric progressions of other basin parameters, leading directly to the power function relationships between variables, known as allometric growth. This model is identical to one proposed to explain the numbers of market areas per order in a system of cities. In addition, the model predicts the structure of bile ducts in one bovine liver cited in this paper.

Field of study: Geology
Discussion of the progress report of the Federal-Provincial Committee on Huronian Stratigraphy

It is argued that the term "Huronian", which has been, and still is, widely used as a time-stratigraphic term, serves a useful purpose in correlating the early Proterozoic rocks of Ontario with those of the Lake Superior region. It should not be used, therefore, as a rock-stratigraphic name of only local significance, as has been suggested in the progress report of the Federal-Provincial Committee on Huronian Stratigraphy, but be retained as an informal 'systemic' name pending clarification of conflicting results of age relationships of early Proterozoic rocks of the Great Lakes region. I A scheme of stratigraphic nomenclature is tentatively outlined for the early Proterozoic rocks of the Great Lakes region.

Field of study: Environmental science
InGaSb Defect Filter Layer to Improve Performance of GaSb Solar Cells Grown on GaAs Substrates

The reduction of the threading dislocation density in metamorphic GaSb grown on GaAs substrates through the use of InGaSb defect filter layers has been investigated. More specifically, we study the effects of strain and thickness on the ability of a InGaSb defect filter layer to reduce threading dislocations in GaSb solar cells grown on GaAs substrates. The strain between the GaSb metamorphic layer on GaAs substrate (99.5% relaxed) and the InGaSb defect filter layer is varied by changing the indium composition in the InGaSb layer. It is demonstrated that an InGaSb defect filter layer with 0.6% strain is more effective for blocking threading dislocations compared with higher-strain layers, resulting in improved short-circuit current (Jsc) and open-circuit voltage (Voc) for the metamorphic GaSb solar cell. The optimization of the defect filter layer involves varying the thickness of the layer to achieve the lowest possible threading dislocation density. This also takes into account the critical thickness of the InGaSb layer on GaSb to avoid generation of threading dislocations from the InGaSb layer itself. It is shown that adding an In0.11Ga0.89Sb defect filter layer with thickness of 250 nm and 0.6% strain beneath a GaSb solar cell grown on a GaAs substrate improves Voc from 0.1 V to 0.16 V and Jsc from 19.7 mA/cm2 to 24.7 mA/cm2.

Field of study: Materials science
Zygotic expression of the zebrafish Sox-19, an HMG box-containing gene, suggests an involvement in central nervous system development.

The zebrafish Sox-19 belongs to the Sry subfamily of HMG (Hight Mobility Group) box genes and is closely related to the Sox sub-group B, comprising the mouse Sox-1, Sox-2 and Sox-3 genes, with respect to both HMG box homology (95.3%) and neural expression during embryogenesis. Analysis of Sox-19 expression during embryogenesis by whole-mount in-situ hybridization revealed interesting features. In early gastrula embryos, Sox-19 transcripts are detected within a circular area in the region of the presomptive central nervous system (CNS) and appears to be the earliest molecular marker of the CNS in vertebrates. In the developing brain, ZfSox-19 mRNA is distributed in the ventral region of the diencephalon, midbrain and hindbrain whereas the expression is excluded from the telencephalon. In spite of the ventral localisation of its mRNA, the expression of this ZfSox-19 gene is completely normal in cyclops embryos which implies that ZfSox-19 expression is independent of the presence of the floor plate.

Field of study: Biology
Insulin receptor antibodies in diabetes mellitus.

Sera from 80 subjects with IDDM and NIDDM, together with sera from 20 patients with miscellaneous autoimmune conditions and 20 healthy adult subjects were tested for insulin receptor antibodies by (1) inhibition of 125I-insulin binding to EBV-transformed lymphoid cells, and by (2) immunoprecipitation of solubilized insulin receptors in the presence of an excess of mono-specific anti-human IgG or IgM; this test allowed the assessment of the class of antibody activity. Anti-insulin antibodies in the sera were also measured using a double antibody technique. Anti-insulin receptor antibodies were found in 13 of 33 subjects with IDDM and six of 47 with NIDDM. These were principally in the IgM class, and in both groups of diabetics there was a good correlation between % inhibition of insulin binding to intact cells, and % of antibody precipitated by IgM (P less than 0.001), but not by IgG (P greater than 0.1). There was also a good correlation between the % inhibition of insulin binding to intact cells and the daily dose of insulin used in treatment (P less than 0.001). Insulin antibodies were found in seven of 33 subjects with IDDM and six of 12 with NIDDM, all of whom were on insulin treatment. These six subjects were the only ones with NIDDM who also had anti-insulin receptor antibody activity, suggesting that such antibodies may represent auto-anti-idiotype activity. This study shows that autoimmunity in insulin dependent (Type I) diabetes is not limited to islet cells and that such patients also develop antibodies to the insulin receptor. While three out of five patients with relative insulin resistance (requirement greater than 90 u/day) also showed evidence of insulin receptor antibody activity, the clinical significance of these antibodies has yet to be determined.

Field of study: Biology, Medicine
Unraveling the Veil of Subspace RIP Through Near-Isometry on Subspaces

Dimensionality reduction is a popular approach to tackle high-dimensional data with low-dimensional nature. Subspace Restricted Isometry Property, a newly-proposed concept, has proved to be a useful tool in analyzing the effect of dimensionality reduction algorithms on subspaces. In this paper, we provide a characterization of subspace Restricted Isometry Property, asserting that matrices which act as a near-isometry on low-dimensional subspaces possess subspace Restricted Isometry Property. This points out a unified approach to discuss subspace Restricted Isometry Property. Its power is further demonstrated by the possibility to prove with this result the subspace RIP for a large variety of random matrices encountered in theory and practice, including subgaussian matrices, partial Fourier matrices, partial Hadamard matrices, partial circulant/Toeplitz matrices, matrices with independent strongly regular rows (for instance, matrices with independent entries having uniformly bounded $4+\epsilon$ moments), and log-concave ensembles. Thus our result could extend the applicability of random projections in subspace-based machine learning algorithms including subspace clustering and allow for the application of some useful random matrices which are easier to implement on hardware or are more efficient to compute.

Field of study: Engineering
An integer ambiguity resolution algorithm for real-time GPS attitude determination

The problem of integer ambiguity resolution must be solved to fully exploit the information contained in the GPS carrier phase measurements for real-time attitude determination. A new algorithm for integer ambiguity resolution that uses single-difference smoothed pseudorange measurements is proposed that has several advantages over the conventional algorithms such as the search methods and the motion-based algorithms. These advantages include minimal computational effort at each epoch and an analytically derived equation which calculates the expected time to ambiguity resolution. The validity and the performance of the new algorithm are investigated through simulations although processing real data will be necessary to verify the usability of the proposed algorithm in real situations.

Field of study: Mathematics
Multi-Functional Laccase Immobilized Hydrogel Microparticles for Efficient Removal of Bisphenol A

Hghly stable, reusable, and multi-functional biocatalytic microparticles with Laccase (Lac) enzyme (Lac/particles) were synthesized for bisphenol A (BPA) removal from aqueous solution. The Lac/particles were prepared by encapsulating Lac enzymes into poly ethylene glycol (PEG) hydrogel via the UV assisted emulsion polymerization method followed by cross linking with glutaraldehyde (GA). The obtained Lac/particles were spherical and micron sized (137–535 μm), presenting high enzyme entrapment efficiency of 100%, high activity recovery of 18.9%, and great stability at various pHs (3–7) than the free Lac. The Lac/particles could adsorb the BPA into the catalytic particles in a short time, promoting contact between BPA and enzyme, and further enzymatically degrade them without the shaking process and independent surrounding buffer solution. The Lac/particles could be reused for another round BPA adsorption and biotranformation by maintaining over 90% of BPA removal efficiency after seven times reuse. The synergistic effects of adsorption and biocatalytical reaction of Lac/particles have significant values in high efficient and cost-effective BPA removal.

Field of study: Materials science
Effect of chronic exposure to cadmium on hepatic drug metabolism.

: In an attempt to examine the chronic effect of low levels of cadmium on hepatic drug-metabolizing enzyme system, an experiment was carried out in which growing male rats were given 0, 5, 10, and 20 ppm of cadmium in drinking water for a period of 8 weeks. An ip administration of a hypnotic dose of pentobarbital to the cadmium-treated and the control rats 24 hr following the termination of the experiment exhibited that there was no significant difference in the drug metabolism in control and any of the treated groups. Next, liver microsomes were isolated from animals in all groups to study their ability to metabolize drugs in vitro. The results indicated that the activity of benzphetamine N-demethylase and aniline hydroxylase, and the concentration of microsomal cytochrome P-450 were almost identical in the control and treated groups. On the other hand, a single ip dose of cadmium (2 mg/kg) caused significant decrease in the vivo and in vitro microsomal drug metabolism. These results suggest that although a single ip dose of cadmium (2 mg/kg) causes significant inhibition of drug metabolism, chronic exposure to cadmium up to 20 ppm in drinking water over a period of 8 weeks is unlikely to affect hepatic drug metabolism.

Field of study: Agricultural and Food sciences
Study on Question-based Object-Oriented Knowledge Representation

Question-based object-oriented knowledge representation method overcomes the shortcomings that the process of formalizing knowledge is very complicated in the course of constructing repository and the efficiency of searching texts is very low. The method uses the types of questions as attribute earmarks and these earmarks are tagged in the texts. The repository is composed of the texts marked, database stores the class relation. In the question answering system used texts as the elements of repository, Question-based object-oriented knowledge representation method can locate the site of answers rapidly by analyzing the types of questions, that increases efficiency of extracting information directly from original texts.

Field of study: Computer science
Kinetic parameter estimation from attenuated SPECT projection measurements

Conventional analysis of dynamically acquired nuclear medicine data involves fitting kinetic models to time-activity curves generated from regions of interest defined on a temporal sequence of reconstructed images. However, images reconstructed from the inconsistent projections of a time-varying distribution of radiopharmaceutical acquired by a rotating SPECT system can contain artifacts that lead to biases in the estimated kinetic parameters. To overcome this problem the authors investigated the estimation of kinetic parameters directly from projection data by modeling the data acquisition process. To accomplish this it was necessary to parametrize the spatial and temporal distribution of the radiopharmaceutical within the SPECT field of view. In a simulated transverse slice, kinetic parameters were estimated for simple one compartment three myocardial regions of interest, as well as for the liver. Myocardial uptake and washout parameters estimated by conventional analysis of noiseless simulated data had biases ranging between 1-63%. Parameters estimated directly from the noiseless projection data were unbiased as expected, since the model used for fitting was faithful to the simulation. Predicted uncertainties (standard deviations) of the parameters obtained for 500,000 detected events ranged between 2-31% for the myocardial uptake parameters and 2-23% for the myocardial washout parameters.

Field of study: Physics
EDITOR'S PERSPECTIVE ON ARTICLE 1: Mechanisms of edema formation after intracerebral hemorrhage: effects of thrombin on cerebral blood flow, blood-brain barrier permeability, and cell survival in a rat model

The authors use a highly reproducible model to simulate spontaneous intracerebral hemorrhage in rats. The progressive mass effect that develops over several days after hemorrhage is largely due to edema formation in brain parenchyma adjacent to the clot. The specific mechanisms that are responsible for the enlarging lesion are explored in well-designed and executed experiments. The toxic effect of thrombin, released during the clotting process, on brain parenchyma has been identified as well as a therapeutic window when specific treatment can interrupt edema formation around the hematoma.

Field of study: Medicine
Biochemical and functional characterization of the synaptic vesicle-associated form of CA2+/calmodulin-dependent protein kinase II.

Ca+/calmodulin-dependent protein kinase II (CaMPKII) is a brain-enriched protein kinase that plays important roles in synaptic transmission and plasticity. In nerve terminals, a form of CaMPKII is associated with synaptic vesicles and binds the COOH-terminal region of synapsin I (SYNI). The biochemical properties of the vesicle-associated form of CAMPKII have been investigated and compared with those of the soluble forebrain enzyme. Both the alpha- and beta-subunits of CaMPKII copurifying with synaptic vesicles were tightly associated with the vesicle membrane. The vesicle-associated form of CaMPKII was indistinguishable from the soluble form with respect to sites of autophosphorylation, kinetics of both autophosphorylation and SYNI phosphorylation, and induction of autonomous activity upon autophosphorylation. Although both subunits of the soluble CaMPKII interacted with a photoactivatable SYNI derivative, only the alpha-subunit of the synaptic vesicle-associated CaMPKII bound to the COOH-terminal region of SYNI. The latter interaction was strongly dependent on the phosphorylation state of SYNI and on divalent cations, but appeared to be independent of autophosphorylation. These results demonstrate that, although the vesicle-associated form of CaMPKII is catalytically indistinguishable from the soluble form, it exhibits distinct characteristics concerning its association with the vesicle membrane and with SYNI.

Field of study: Biology
Permafrost response to increasing Arctic shrub abundance depends on the relative influence of shrubs on local soil cooling versus large-scale climate warming

Deciduous shrub abundance is increasing across the Arctic in response to climatic warming. In a recent field manipulation experiment in which shrubs were removed from a plot and compared to a control plot with shrubs, Blok et al (2010 Glob. Change Biol. 16 1296–305) found that shrubs protect the ground through shading, resulting in a ~ 9% shallower active layer thickness (ALT) under shrubs compared to grassy-tundra, which led them to argue that continued Arctic shrub expansion could mitigate future permafrost thaw. We utilize the Community Land Model (CLM4) coupled to the Community Atmosphere Model (CAM4) to evaluate this hypothesis. CLM4 simulates shallower ALT (~− 11 cm) under shrubs, consistent with the field manipulation study. However, in an idealized pan-Arctic + 20% shrub area experiment, atmospheric heating, driven mainly by surface albedo changes related to protrusion of shrub stems above the spring snowpack, leads to soil warming and deeper ALT (~+ 10 cm). Therefore, if climate feedbacks are considered, shrub expansion may actually increase rather than decrease permafrost vulnerability. When we account for blowing-snow redistribution from grassy-tundra to shrubs, shifts in snowpack distribution in low versus high shrub area simulations counter the climate warming impact, resulting in a grid cell mean ALT that is unchanged. These results reinforce the need to consider vegetation dynamics and blowing-snow processes in the permafrost thaw model projections.

Field of study: Environmental science
Experimental Study on Superplastic Extrusion of Spur Gear

The superplastic extrusion of spur gears wos studied.The manner of extrusion is radial and the experiment material is Pb-Sn alloy.In order to reduce load,the divided flow method was used in the experiment.The experimental results show that it is feasible to machining the spur gear with superplastic extrusion process.The divided flow method has merits in the fields of inducing forming load and improving metal ability to fill in mould,which provides a feasible basis for practice use.

Field of study: Materials science
Missing Boundaries of Comparison: The Political Community

How and where should the balance lie between lofty principles of human solidarity and the self-interest which drives the indispensable market? This remains the puzzler today that it was for Alexis de Tocqueville. Writing on Democracy in America in the 1840s, he saw in Americans' "habits of the heart" (their customs and values) a tension between community solidarity and self-centered individualism that might endanger democracy.1 In the United States, foundations and centers across a wide ideological spectrum have appeared, dedicated to save the purportedly failing political community.2 The political community and its relation to individual autonomy pose a "central issue" of political  In contrast to political thought and to public discourse, the field of comparative politics almost ignores the political community as either a normative issue

Field of study: Political science
Simulation analysis of cold-test characteristics of pitch-tapered helical slow-wave structure

Based on the MAFIA simulation platform,the effects of helix pitch on dispersion,interaction impedance and attenuation characteristics are analyzed for an ultra-wide band(4~18 GHz) helical slow-wave structure.The rules of the cold-test characteristics changing with helix pitch are also studied and it turns out that,with increasing helix pitch,the phase velocity increases linearly,the interaction impedance changes nonlinearly and the attenuation constant decreases nonlinearly.At the same time,with the limitation of the synchronism between the electron beam and the electromagnetic wave,the change of pitch is small and therefore an approximate linear relation can be introduced.Based on these effects and rules,the linear interposition method is suggested to get the cold-test characteristics for structures with linearly-tapered pitch.

Field of study: Physics
Very Fast Routing Table Lookup and Update Algorithm Based on Index and Compression

Internet protocol (IP) address lookup is a critical function of the network processors. While lots of solutions to this problem have been presented, few of them achieves line rate lookup and high update performance, high memory efficiency, and low hardware cost simultaneously. It is popular to use the content addressable memory devices for current commercial products, but it is a high cost, high power solution, particularly when applied to large databases. This paper presentes a novel high performance routing table lookup and update algorithm. According to the all-around performance, such as search and update performance, cost and consuming power, this work is better than the state-of-the-art. This algorithm is based on the index and compressed bit vector. Here not only one SRAM access cycle routing table lookup performance is accomplished but also two SRAM access cycles update performance is achieved in a pipelined scheme. The search and update process is illustrated in details. A maximum 530k routing entries can be held in about 1Mbytes SRAM space.

Field of study: Computer science
The late proterozoic glacial era

The Late Proterozoic glacial record is reviewed on a global basis as a setting and introduction for that part of the symposium concerned with West African tillites. No unequivocal glacial deposits have yet been recorded in the interval 1.0–2.0 Ga. Late Proterozoic glacial epochs have been grouped into three main periods namely: Lower Congo (c. 0.9 Ga), Sturtian (c. 0.8 Ga) and Varangian (c. 0.65 Ga), and a possible final Late Sinian Epoch near the Precambrian-Cambrian boundary. The Ediacaran Epoch, with its metazoan fauna follows Varangian and in part at least precedes Late Sinian. The Sturtian and Varangian glacial periods each comprise at least two main glacial epochs, the tillites of which are widespread. Chronometric ages are currently disputed and the values given are for identification in the literature rather than to provide chronometric definition. Of all the glacial epochs, only those of the Varangian glacial period appear to be represented in West Africa. It has been argued that Varangian tillites were of global extent, many forming in tropical latitudes, though some authors prefer a hypothesis of polar wandering to limit glaciation to polar latitudes.

Field of study: Environmental science, Geography