nils-herrmann/clean_scirepeval huggingface dataset:
Ablation of ATJ Graphite at High Temperatures

Results of an extensive experimental program on the ablation of ATJ graphite in air at surface pressures of 0.3 to 4.4 atm and surface temperatures of 2570 to 4030 K are presented. The measured mass-loss rates are correlated with surface temperature, pressure, and effective nose radius. The results are compared with several equilibrium thermochemical ablation theories which differ basically in the chemical species that are considered and in the thermodynamic properties assigned to these species. All the theories predict about the same mass-loss rate in the diffusion-controlled oxidation regime and are in good agreement with the experimental results. At higher temperatures, however, the experimental and theoretical results do not agree. At temperatures above 3700 K, the experimental mass-loss rate becomes independent of pressure and an exponential function of temperature. A comparison of the high-temperature results with the theories indicates that all the theories, except the one based on the thermodynamic properties from the JANAF tables, are invalid because they overpredict the mass-loss rate. On the other hand, the theory based on the JANAF properties underpredicts the measured mass-loss rate by a factor of three at 4000 K. At least a portion of this difference between experiment and theory is attributed to particulate mass loss which is visually observed.

Field of study: Physics
Synthesis and Structure Determination of an Oxygen-Functionalized Ruthenacycle: Intramolecular Attack of Coordinated Hydroxide on an Acetylenic Ligand

The reaction of a tetranuclegar hydroxoruthenium complex [(η5-C5Me5)Ru(μ3-OH)]4 (1) with dimethyl acetylenedicarboxylate (DMAD) proceeded at 60 °C to generate a dinuclear oxygen-functionalized ruthenacycle [(η5-C5Me5)Ru]2[μ-η5-OC4(CO2Me)4] (2) via an intramolecular attack of hydroxo ligand on the coordinated C-C unsaturation. The molecular structure of 2 was determined by X-ray diffraction.

Field of study: Chemistry
Complexity of Quaternary aeolian dynamics (Canary Islands)

Carbonate aeolianites are important Quaternary archives at the point of intersection between marine and terrestrial systems. Since they are composed of alternating aeolian sediments and several paleosol units, these sequences are highly suitable to reconstruct palaeoenvironmental conditions. In northern Fuerteventura, at least five different areas are characterised by successions of different dune generations and paleosols. Few studies have addressed the stratigraphic order of individual dune areas. Therefore, a comprehensive consideration spanning several dune fields is needed. Here, we aim to present a detailed stratigraphy of two different dune areas and to identify the contribution of different materials (shelf origin, dust origin, volcanic origin) along with processes (accumulation, soil formation, erosion/preservation) that build up these archives. Four key sections were selected and sampled for laboratory analyses (texture, elemental composition, CaCO3 content, palaeoenvironmental magnetics, luminescence dating, and gastropod assemblages). Based on main stratigraphic features, five major sedimentary sequences were identified indicating differences in prevailing sediment supply, humidity, and volcanic activity. First luminescence dating (IRSL) of the sequences revealed sedimentation ages between 360 ka and 15 ka. Finally, we are able to demonstrate that different dune areas show comparable stratigraphic patterns, but each studied site is defined by certain characteristics depending on the respective features of the closer surrounding. The knowledge of these peculiarities and the underlying background is essential in order to correlate different sites and to attempt an appropriate environmental interpretation of the sedimentary sequences.

Field of study: Environmental science, Geography
Femtosecond-laser micromachined optical waveguides in Bi4Ge3O12 crystals.

The optical waveguides in Bi(4)Ge(3)O(12) (BGO) crystals in both depressed-cladding and dual-line configurations have been produced using femtosecond-laser micromachining. The guiding properties and thermal stabilities of the BGO waveguides have been investigated for both geometries, showing different performance of the fabricated structures. Both depressed-cladding and dual-line waveguides support guidance along both TE and TM polarizations. Thermal annealing treatments up to 600°C reduce the propagation loss of dual-line waveguides to as low as 0.5 dB/cm, while the cladding waveguide is only stable under thermal treatment not higher than 260°C, reaching a propagation loss of 2.1 dB/cm.

Field of study: Physics
A STRUCTURAL TOPOLOGICAL OPTIMIZATION METHOD BASED ON EXPLORING CONCEPTUAL ROOT

This paper introduces the transformation of the 0-1 discrete variables into continuous variables in topological optimization problem by ICM (Independence, continuous and Mapping) method. The first step is to convert equivalently the discrete problem into continuous problem taking advantages of the step-up function; The second step is to define the polish function to approach the step-up function; The third step is to establish the mapping model by introducing the filter function which is the inverse function of the polish function; The fourth step is to solve the model with continuous variables by some smooth algorithms. Some representative numerical examples of continuous structures have illustrated the process of transforming the topological optimization model into independent level one. This method and the numerical solutions show that the method is also suitable for pure mathematical optimization problems with 0-1 discrete variables.

Field of study: Engineering
Conjunctive Measurement of Aquatic Exercise in an Office Setting

The Hydrotrack, a treadmill immersed in a water bath, is designed to provide an in-office approach to aquatic therapy. 24 clinical clients in an outpatient sports medicine practice were invited to use the Hydrotrack as part of their rehabilitation treatment. Our purpose was to describe the way(s) in which the Hydrotrack is useful in rehabilitation treatment. Exercise protocols designed by a physical therapist were used for each subject. We monitored an external criterion, heart rate, to measure the subjects' exertion during the exercise process. Self-reported ratings of exercise efficacy and exertion were also used to quantify the subjects' performance on the Hydrotrack. Heart-rate values and self-report ratings supported the usefulness of this device in physical therapy.

Field of study: Psychology
Non-Equilibrium behavior of dopants during epitaxial silicon deposition using silane

Experimental studies show that the incorporation of a common gas phase dopant, AsH3 or B2H6, during the pyrolysis of silane results in a decrease in the deposition rate of silicon epitaxial layers. At low doping levels, the results are consistent with the dilute solution theory. At high doping levels, however, a deviation occurs from the equilibrium solubility conditions. Data show a reduction in deposition rate by as much as 40 percent for 10 percent AsH3/SiH4 ratios and about 20 percent for 10 percent B2H6/SiH4 ratios. The growth of retrograde junctions, where these inhibitions are most critical, are discussed.

Field of study: Materials science
Ten Black Dots and September 11: Integrating Social Studies and Mathematics through Children's Literature

Because of the pressure to increase test scores in reading and mathematics, content areas such as social studies are being eliminated from many elementary schools' curricula. It is critical that teachers find ways to integrate social studies into reading and mathematics. Social studies and mathematics may not immediately come to mind when considering subject area integration; however, these content areas can be effectively integrated through the use of children's literature and engaging activities. Research supports both curriculum integration and the use of children's literature in all content areas. Teachers must use effective methods for weaving subject areas together in ways that will motivate students and cover required state standards. This activity is an example of an activity that teachers can use to integrate social studies and math through the use of children's literature.

Field of study: Sociology
A possible mechanism of TPA-mediated downregulation of neurotrophin-3 gene expression in rat cultured vascular smooth muscle cells.

We have previously reported that in cultured rat vascular smooth muscle cells (VSMCs), neurotrophin-3 (NT-3) gene expression was suppressed by TPA (12-O-tetradecanoyl phorbol-13-acetate), which induces an AP-1 transcription factor. In the present study, to clarify the mechanism for TPA-mediated downregulation of NT-3 gene expression, effects of cycloheximide and dexamethasone (Dex) on the TPA-mediated downregulation were examined in VSMCs. Pretreatment with cycloheximide, an inhibitor of protein synthesis, or simultaneous treatment with Dex, an inhibitor of AP-1, suppressed the TPA-mediated downregulation of NT-3 gene expression. Furthermore, co-transfection of c-fos and c-jun expression vectors into VSMCs resulted in decrease in the NT-3 gene expression. The present findings suggest that TPA-induced AP-1 de novo synthesis causes the downregulation of NT-3 gene expression in VSMCs.

Field of study: Biology
A Discussion of Several Issues Related to the Appraisal of Benchmark Prices of Collective Construction Land

The appraising ofthe collective construction land is still an issue remaining untouched in China's management of land prices, which makes it urgent to study the appraising method and skill. Based on the specific assessment, this paper introduces the characteristics of rural collective construction land price evaluation and assessment process and analyzes the existing key problems of appraising work. For the key problems , including the evaluation scope,delimit boundary of grade,the collection of data, the selection of evaluation parameter , determination of benchmark land price and the cohesion of benchmark land price, the corresponding solution measures are pointed out.

Field of study: Agricultural and Food sciences
Debiased distributed learning for sparse partial linear models in high dimensions

Although various distributed machine learning schemes have been proposed recently for pure linear models and fully nonparametric models, little attention has been paid on distributed optimization for semi-paramemetric models with multiple-level structures (e.g. sparsity, linearity and nonlinearity). To address these issues, the current paper proposes a new communication-efficient distributed learning algorithm for partially sparse linear models with an increasing number of features. The proposed method is based on the classical divide and conquer strategy for handing big data and each sub-method defined on each subsample consists of a debiased estimation of the double-regularized least squares approach. With the proposed method, we theoretically prove that our global parametric estimator can achieve optimal parametric rate in our semi-parametric model given an appropriate partition on the total data. Specially, the choice of data partition relies on the underlying smoothness of the nonparametric component, but it is adaptive to the sparsity parameter. Even under the non-distributed setting, we develop a new and easily-read proof for optimal estimation of the parametric error in high dimensional partial linear model. Finally, several simulated experiments are implemented to indicate comparable empirical performance of our debiased technique under the distributed setting.

Field of study: Computer science
The Nonparametric Estimation of Branching Curves

The spline smoothing approach to nonparametric regression is extended to cover the estimation of curves that branch at certain specified points in time. This extension is motivated and illustrated by data from an experiment on sunflowers. Apart from providing insight into this particular data-analytic problem, the work described demonstrates the power of the roughness penalty approach in coping with curve estimation of a nonstandard kind. Particularly in the context of certain experiments in horticulture and arboriculture, the experimental material may be treated identically to the control up to a certain known time part of the way through the experiment. To display and investigate the effect of treatments applied during growth it is of interest to estimate a branching curve. In the simplest case we want to study two growth curves that are common up to a certain known time and then diverge (or branch) after the application of a treatment to part of the experimental material. The spline-smoothing ...

Field of study: Mathematics
Yukon-Tanana terrane in the southern Campbell Range, Finlayson Lake belt, southeastern Yukon: the geological setting of retrogressed eclogite of the Klatsa metamorphic complex

Tanana terrane in the southern Campbell Range is composed of rocks that have different metamorphic, exhumation, and structural histories, and that have formed in disparate parts of the Paleozoic Yukon–Tanana volcanic arc. The geological relationships in the southern Campbell Range reveal the tectonic and structural history of the Klatsa metamorphic complex, which represents the remnants of an Early Mississippian subduction zone beneath the Yukon–Tanana arc. The Klatsa metamorphic complex is composed of foliated to massive serpentinite, leucogabbro, amphibolite, and retrogressed eclogitic quartz–muscovite schist with lenses of metabasite. It was structurally juxtaposed on Upper Mississippian to Lower Permian metasedimentary rocks of the White Lake, King Arctic, and Money Creek formations. Regional and local structural and stratigraphic relationships suggest that the Klatsa metamorphic complex is part of the Cleaver Lake thrust sheet, the structurally highest thrust sheet in a north- to northeast-verg...

Field of study: Environmental science
BRIEF COMMUNICATIONS: Induced absorption of pump radiation in solutions of organic dyes used as active media in ultraviolet lasers

The dependence of the quantum efficiency of fluorescence on the intensity of pumping with the fourth harmonic of neodymium laser radiation (265 nm) was determined for solutions of several organic compounds (paraterphenyl, PPD, α–NPD, α–NPO, etc.). The reduction in the quantum efficiency with rising pump intensity was attributed to an induced absorption at the pump wavelength. A qualitative comparison was made of the intensity of the induced absorption and laser characteristics of the investigated compounds.

Field of study: Engineering, Physics
Study on the stability of natural pigment for Myrica rubra Steb et zucc.

The stability of red pigment,which were extracted from the Myrica rubra Steb et zucc.,was detected under different temperature,pH,sunlight and mediaeval conditions.The results show that the pigment can dissolve in water,the pigment could be stable under acidity conditions.Sunlight,oxidizing agent,reducing agent,some metallicion and strong alkali conditions could obviously effect the stability of the pigment.

Field of study: Agricultural and Food sciences
A Middle Pleistocene intense monsoonal episode from the Kapthurin Formation, Kenya: Stable isotopic evidence from bovid teeth and pedogenic carbonates

Carbon and oxygen isotope values of bovid tooth enamel and pedogenic carbonates were used to reconstruct the paleoenvironments associated with Middle Pleistocene archeological and paleontological sites from the Kapthurin Formation, Kenya. Fossil teeth and pedogenic carbonates were collected from lacustrine and fluvial facies (K3 and K3’) of the Kapthurin Formation (~ 543–509 ka). Twenty teeth from six bovid tribes and twenty four pedogenic carbonates were sequentially sampled for stable oxygen and carbon analysis. The primary aims of this work are to reconstruct the vegetative habitats of bovids and environmental landscapes from the Kapthurin Formation, assessing the presence of C3, C4, or mixed vegetation and foragers. We also assess general paleoclimate factors, such as overall aridity, seasonal shifts in water availability, and broad habitat reconstructions. Carbon isotope values suggest a wide range of foraging strategies were available to bovids, and are characterized by both C3 dominated and C4 dominated diets, with little evidence for mixed feeders, while pedogenic carbonates suggest the landscape combined a mix of C3 and C4 vegetation sources, structurally similar to wooded grasslands. Paleoclimatic conditions, based on the reconstructed mean annual water deficit from δ18Oenamel values suggest a hyper mesic environment, most comparable to the modern Ituri rainforest, indicating a much wetter climate than the modern Lake Baringo Basin. This environment coincides with an intensified Middle Pleistocene African monsoonal system at the onset of Marine Isotope Stage 13 (~ 533 ka). The Middle Pleistocene Lake Baringo regional habitat appears to have been one dominated by woodland areas, perennially active streams, marsh and sumpland environments, and a surrounding grassland ecosystem. This lush basin would have provided hominins with a diverse and productive ecosystem. Perhaps not surprisingly, archeological sites are found in all habitats, including wet, forested, and grassland environments.

Field of study: Environmental science, Geography
A Discussion of Possibility of Reinforcement Learning Using Event-Related Potential in BCI

Recently, Brain computer interface (BCI) which is a direct connecting pathway an external device such as a computer or a robot and a human brain have gotten a lot of attention. Since BCI can control the machines as robots by using the brain activity without using the voluntary muscle, the BCI may become a useful communication tool for handicapped persons, for instance, amyotrophic lateral sclerosis patients. However, in order to realize the BCI system which can perform precise tasks on various environments, it is necessary to design the control rules to adapt to the dynamic environments. Reinforcement learning is one approach of the design of the control rule. If this reinforcement leaning can be performed by the brain activity, it leads to the attainment of BCI that has general versatility. In this research, we paid attention to P300 of event-related potential as an alternative signal of the reward of reinforcement learning. We discriminated between the success and the failure trials from P300 of the EEG of the single trial by using the proposed discrimination algorithm based on Support vector machine. The possibility of reinforcement learning was examined from the viewpoint of the number of discriminated trials. It was shown that there was a possibility to be able to learn in most subjects.

Field of study: Computer science
Bromination and iodination of 6H,12H-5, 11-methanodibenzo[b,f][1,5] diazocine: A convenient entry to unsymmetrical analogs of Tröger's base

6H,12H-5,11-Methanodibenzo[b,f][1,5]diazocine can easily be prepared from aniline and paraformaldehyde. Its reactions with either N-bromosuccinimide (NBS) or with iodine monochloride (ICl) in the presence of a suitable activator smoothly afford 2-bromo- and 2-iodo- derivatives, respectively. The combination of these halogenation methods provides access to the 8-bromo-2-iodo derivative, which is an interesting and otherwise inaccessible intermediate for the synthesis of unsymmetrical analogs of Troger's base. The reported halogenations represent the first examples of electrophilic substitution in 6H,12H-5,11-methanodibenzo[b,f][1,5]diazocine.

Field of study: Chemistry
Decorrelating multiuser code-timing estimation for long-code CDMA with bandlimited chip waveforms

This paper addresses the problem of multiuser code-timing estimation for asynchronous uplink code-division multiple-access (CDMA) systems with aperiodic spreading codes and bandlimited chip waveforms. Two decorrelating code-timing estimation schemes, namely the frequency-domain least-squares (FLS) and frequency-domain weighted least-squares (FWLS) estimators, are developed. The two proposed estimators offer different tradeoffs between complexity and estimation accuracy. A critical step for decorrelating-based estimation is to decompose the received signal into subsignals of shorter duration. We discuss how to perform the decomposition to ensure improved identifiability and statistical stability of the proposed schemes. Due to a unique signal structure in the frequency domain, both the FLS and FWLS estimators admit efficient implementations that result in significant complexity reductions. The Crame/spl acute/r-Rao bound for the estimation problem under study is derived and used as an assessment tool for the proposed estimators. Numerical results show that both of the proposed estimators can support overloaded systems (with more users than the processing gain) in multipath fading environments and significantly outperform a conventional technique based on matched-filter processing.

Field of study: Engineering
Synthesis and bulk properties of oxychloride superconductor Ca2-xNaxCuO2Cl2

A series of polycrystalline samples and submillimeter size single crystals of a cuprate oxychloride Ca2-xNaxCuO2Cl2 (Na-CCOC) with values of Na content ranging from underdoped to optimally doped regions were synthesized at pressure of 30-55 kbar and temperature of 1250-1700 °C. A systematic variation of the transition temperature Tc with a maximum value of 29 K for x≈0.20 has been found as a function of Na content. In order to check the role of the apical oxygen for high-temperature superconductivity, we performed muon-spin rotation and magnetization studies of the in-plane magnetic penetration depth λabfor Ca2-xNaxCuO2Cl2 samples with x≈0.11, 0.12, 0.15, 0.18, and 0.19. The absolute value of the in-plane magnetic penetration depth at T=0 was found to increase with decreasing doping from λab(0)=316(19) nm for the x≈0.19 sample to λab(0)=430(26) nm for the x≈0.11 one. Based on a comparison of the present Na-CCOC data with the data of La2-xSrxCuO4 cuprate superconductors, it is concluded that replacing of apical oxygen by chlorine decreases the coupling between the superconducting CuO2 planes, leading to an enhancement of the two-dimensional properties of Na-CCOC. The torque studies implies that the anisotropy coefficient λ=84(1) of Ca1.82Na0.18CuO2Cl2 single crystals is much more enhanced compared to the structurally related La1.82Sr0.18CuO4 where for same doping λ is much lower, i.e. γ ≈ 11.

Field of study: Physics
Current management of acute ischemic stroke. Part 1: Thrombolytics and the 3-hour window.

To help family physicians who care for patients with acute stroke or who are involved in planning service delivery or resource allocation to understand recent developments in acute stroke care.



A MEDLINE search indicated that most data were derived from well designed, randomized, double-blind, placebo-controlled trials, including all the largest international studies and large systematic reviews.


MAIN MESSAGE
Treatment of acute stroke with tissue plasminogen activator seems beneficial for certain patients with certain kinds of stroke. Because thrombolytic therapy is not without risk and requires substantial resources, it should be administered only by physicians trained in its use and in centres with the necessary experience and resources. Because time is important, an organized and efficient system of stroke care with collaboration between hospital and prehospital care providers and help from ordinary citizens is essential.



Management of acute stroke is an emerging discipline; many potential therapies are still experimental.

Field of study: Medicine