nils-herrmann/clean_scirepeval huggingface dataset:
KNOOP HARDNESS NUMBERS FOR 127 OPAQUE MINERALS

Knoop indentation hardness numbers may be obtained on polished mineral grains as small as 10 microns in diameter. This paper gives average Knoop numbers for 127 opaque minerals and quartz. The limits of tests and the average hardness number are plotted on a logarithmic scale on which the lines representing the hardness range for a given mineral are reasonably comparable throughout the range from 1 to 1500.

Bismuth (0.7) is the softest mineral tested, berthierite (1140) the hardest. Other representative hardnesses (Talmage-scale equivalents in parentheses) are: argentite, 26 (A); galena, 75 (B); chalcopyrite, 175  niccolite, 460 (E); magnetite, 528 (F); ilmenite, 965 (G). Quartz, 467 (7 on the Mohs scale), is approximately equivalent on the Knoop scale to niccolite, 460 (5–5½ on the Mohs scale), and goethite, 476 (5–5½ on the Mohs scale), and softer than magnetite, 536 (5½–6½ on the Mohs scale).

Some minerals exhibit striking differences in hardness in different crystallographic orientations. Molybdenite has a hardness of 12 parallel to {0001} cleavage and 60 at right angles to the cleavage; hucbnerite is 313 parallel to {010} cleavage and 463 at right angles to cleavage; enargite is 154 parallel to {110} cleavage and 378 at right angles to cleavage.

Field of study: Geology
Evaluation of the clinical utility of a carotid bruit.

Uncertainty exists over whether listening for carotid bruits as part of the clinical examination is informative in terms of predicting the presence or severity of carotid stenosis.



We sought to undertake a comprehensive meta-analysis and meta-regression of all studies to date that have assessed the relationship between a carotid bruit and severity of degree of stenosis.



Electronic databases were used to identify all published studies in humans evaluating the association between bruit and stenosis published until and including October 2011. Pooled sensitivity, specificity and diagnostic odds ratio (DOR) were calculated for each stenosis group. Summary receiver operating characteristic (SROC) curve analysis was performed in studies assessing clinically relevant (i.e. >70%) stenosis. Meta-regression was performed in all studies, using random effects.



We identified 26 studies evaluating the association between carotid bruit and stenosis, in 15 117 arteries. For clinically relevant stenosis (i.e. >70%), we found pooled sensitivity 0.53 [95% confidence interval (CI): 0.5-0.55], specificity 0.83 (95% CI: 0.82-0.84) and DOR 4.32 (95% CI: 2.78-6.66). SROC curve analysis gave an area under the curve of 0.73. Meta-regression analysis showed a (non-significant) (P = 0.067) inverse relationship between carotid bruit and stenosis.



The carotid bruit is of moderate value for detecting clinically relevant carotid stenosis. It gives high specificity but low sensitivity. The likelihood of a carotid bruit does not increase at increasing degrees of stenosis.

Field of study: Medicine
Numerical approach to the waiting time for the one-dimensional porous medium equation

We consider the nonlinear degenerate diffusion equation. The most striking manifestation of the nonlinearity and degeneracy is an appearance of interfaces. Under some condition imposed on the initial function, the interfaces do not move on some time interval [0, t*]. In this paper, from numerical points of view, we try to determine the value of t*, which is called the waiting time.

Field of study: Mathematics
Putative Mitochondrial Sex Determination in the Bivalvia: Insights From a Hybrid Transcriptome Assembly in Freshwater Mussels

Bivalves exhibit an astonishing diversity of sexual systems, with genetic and environmental determinants of sex, and possibly the only example of mitochondrial genes influencing sex determination pathways in animals. In contrast to all other animal species in which strict maternal inheritance (SMI) of mitochondria is the rule, bivalves possess a system known as doubly uniparental inheritance (DUI) of mitochondria in which maternal and paternal mitochondria (and their corresponding female-transmitted or F mtDNA and male-transmitted or M mtDNA genomes) are transmitted within a species. Species with DUI also possess sex-associated mtDNA-encoded proteins (in addition to the typical set of 13), which have been hypothesized to play a role in sex determination. In this study, we analyzed the sex-biased transcriptome in gonads of two closely-related freshwater mussel species with different reproductive and mitochondrial transmission modes: the gonochoric, DUI species, Utterbackia peninsularis, and the hermaphroditic, SMI species, Utterbackia imbecillis. Through comparative analysis with other DUI and non-DUI bivalve transcriptomes already available, we identify common male and female-specific genes, as well as SMI and DUI-related genes, that are probably involved in sex determination and mitochondrial inheritance in this animal group. Our results contribute to the understanding of what could be the first animal sex determination system involving the mitochondrial genome.

Field of study: Biology
Diatom paleolimnology of late Pliocene Baringo Basin (Kenya) paleolakes

Kenya's Baringo-Tugen Hills-Barsemoi drill site is one of six localities across Kenya and Ethiopia from which the Hominin Sites and Paleolakes Drilling Project has obtained sediment cores in an effort to investigate the role of environmental forcing in shaping human evolution. The Baringo Basin site features extensive exposures of the Chemeron Formation, which contains >100 fossil vertebrate localities including five hominin sites. The 228-m drill core, dating from ~3.29 to 2.56 Ma, is characterized by fluvio-lacustrine sediments, including multiple diatomites, with evidence of variable degrees of later pedogenic modification. In the lower part of the core (~3.29–3.04 Ma), diatoms were preserved only in very low abundance, consistent with predominantly fluvial or lake marginal environments. In contrast, five diatomites and two additional diatom-rich intervals were deposited after ~3.04 Ma, reflecting a major shift in the basin hydrology. Planktonic freshwater species dominated these diatom-rich intervals, whereas periphytic taxa were present in proportions less than 2%, suggesting that these intervals represent open-water deposition during lake highstands. Littoral or saline assemblages are largely absent throughout the core. Instead, we observed a pattern of increasing diatom frustule dissolution at the tops and bottoms of diatomite units, indicating increased alkalinity during the transgressive/regressive phases. A Na-bearing zeolite (analcime) indicative of saline waters precipitated in clastic-dominated intervals between diatomites, suggesting extreme environmental variability between lake highstands and lowstands. Diatom assemblages were consistently dominated by a few species belonging to the genera Aulacoseira and Stephanodiscus, which were at times co-dominant. We infer that assemblages dominated by Aulacoseira represent a well-mixed lake with abundant supply of silica. When Stephanodiscus was dominant, which occurred more frequently in the later freshwater phases, we infer incomplete mixing and reduced silica flux to the epilimnion (upper water layer).

Field of study: Environmental science, Geography
A comparison of college physical education teaching in mainland China and Taiwan.

The authors compared the current conditions of college physical education teaching in mainland China and Taiwan.College physical education teaching in mainland China emphasizes lifetime sport and health first,bases mainly on developing students' physical makings and cultivating their sports skills,places evaluation key factors on physical makings,techniques/skills and sports abilities;college physical education teaching in Taiwan emphasizes leisure intensified,independent and diversified development,bases mainly on developing students' sports abilities and personality,and adopts diversified evaluation.

Field of study: Education
Surface modification and electrochemical properties of cobalt-based layered perovskite cathodes for intermediate-temperature solid oxide fuel cells

PrBaCo2−xCuxO5+δ (0 ≤ x ≤ 0.2, PBCCO) layered perovskite materials were studied as cathode materials for low-temperature solid oxide fuel cells. The electrical conductivity of PBCCO decreased with an increase in Cu content, and PrBaCo1.8Cu0.2O5+δ (PBCCO20) showed the lowest electrical conductivity of 570 S cm−1 at 750 °C. In order to enhance the kinetics of the oxygen reduction reaction on the surface of PBCCO, Au-decorated PBCCO (Au@PBCCO) having gold nanoparticles on their surface was prepared by sputtering. The TEM-EDS analysis confirmed that gold nanoparticles were uniformly formed on the surface of PBCCO. Cu ions on the PBCCO surface bond with the Au nanoparticles, serving as anchors to maintain the nanoscale particle size even after heat treatment at high temperature. The Au@PBCCO showed a 60% lower polarization resistance value at 700 °C than that of the PBCCO20 due to enhanced ORR activity. We hypothesize that this enhancement is due to the fact that the electron transfer to the surface of PBCCO by the gold nanoparticles is promoted and the reduction of oxygen adsorbed on the surface increased.

Field of study: Materials science
The Nature and Origin of the Granulites of Mont Tremblant Park, Quebec

The Mont Tremblant Park granulites can be divided into two main groups: pink, quartzofeld-spathic rocks and green-gray hypersthenic rocks. The quartzofeldspathic granulites are interlayered with garnet-sillimanite gneisses and locally occur as cores of folds or large massifs. More commonly, they are regionally interbanded with the hypersthene granulites. All the granulites are intruded by the quartz mangerites of the Morin anorthosite suite. Geochemical considerations based on ternary variation diagrams and relationships in the albite-orthoclase-anorthite system show that the two groups of granulites have different compositional trends, converging at the extreme granitic end. Mineralogical and geochemical data are consistent with granulite facies conditions of metamorphism. The composition of the granulites and their field relationships are consistent with their postulated derivation from a graywacke-shale geosynclinal sequence. Under granulite facies conditions, partial anatexis formed granitic melts. This anatectic differentiation caused the graywackes to attain a composition appropriate to form hypersthenic rocks and the shales to produce quartzofeldspathic rocks with residual sillimanite-garnet layers. These rocks were deformed during the intrusion of the anorthosite suite, and the characteristic fabrics of the granulites were produced. Volatiles given off by late-stage granite magmas caused retrograde effects at contacts.

Field of study: Geology
Time to Move On? When Entity Theorists Perform Better Than Incremental Theorists

Previous research has shown that when confronted with failure, individuals with a fixed view of intelligence (entity theorists) perform worse on subsequent tasks than those with a malleable view of intelligence (incremental theorists). This study finds that entity theorists perform worse than incremental theorists only when they believe that a subsequent task measures the same ability as the task they previously failed. However, when individuals believe that the subsequent task measures an ability unrelated to the ability needed for the initial failed task, incremental theorists perform worse than entity theorists. Across five studies, we show that entity theorists are more likely to choose a different-ability task as a second task and perform better than incremental theorists on that task. We also examine the role of thoughts about previous failure in the performance differences.

Field of study: Psychology
Biological Robustness: Paradigms, Mechanisms, and Systems Principles

Robustness has been studied through the analysis of data sets, simulations, and a variety of experimental techniques that each have their own limitations but together confirm the ubiquity of biological robustness. Recent trends suggest that different types of perturbation (e.g., mutational, environmental) are commonly stabilized by similar mechanisms, and system sensitivities often display a long-tailed distribution with relatively few perturbations representing the majority of sensitivities. Conceptual paradigms from network theory, control theory, complexity science, and natural selection have been used to understand robustness, however each paradigm has a limited scope of applicability and there has been little discussion of the conditions that determine this scope or the relationships between paradigms. Systems properties such as modularity, bow-tie architectures, degeneracy, and other topological features are often positively associated with robust traits, however common underlying mechanisms are rarely mentioned. For instance, many system properties support robustness through functional redundancy or through response diversity with responses regulated by competitive exclusion and cooperative facilitation. Moreover, few studies compare and contrast alternative strategies for achieving robustness such as homeostasis, adaptive plasticity, environment shaping, and environment tracking. These strategies share similarities in their utilization of adaptive and self-organization processes that are not well appreciated yet might be suggestive of reusable building blocks for generating robust behavior.

Field of study: Biology
The Pacific International Waters Project: Aims, approaches and challenges

This paper focuses on pilot activities being carried out under the Integrated Coastal Watershed Management component of the Pacific International Waters Project (IWP). The paper discusses a two-pronged approach being taken to address the root causes of identified threats to the international waters of 14 Pacific Island countries. National and local level activities are focusing on coastal fisheries, waste management and freshwater protection. The integrated strategic approach of participatory planning processes, social analysis, resource economics and communications in identification of environment problems, their causes and potential solutions for supporting behavioural change in relation to resource use and management is discussed. Some examples of country activities to date are provided. Although it is too early to assess a full range of lessons and project impacts, a number of key issues continue to provide challenges for the implementation of a large regional programme such as the IWP. They include: multi-sectoral stakeholder engagement; the establishment of partnerships needed to support integrated coastal management; and national capacity to implement community-based resource management projects.

Field of study: Environmental science
Effect of Electrical Parameters on Corrosion Resistance of MAO Coating Fabricated on Mg Alloy Under Unipolar Mode

Ceramic coating was obtained by micro-arc oxidation technique on AZ91D Mg alloy under unipolar mode in silicate-aluminate dual electrolyte.The effects of electrical parameters(current density,positive duty cycle,treating time and frequency) on the corrosion resistance of MAO coating fabricated on the Mg alloy were investigated by an orthogonal experiment of four factors with three levels.The results show that the order of affecting corrosion resistance from high to low is as follow: treating time,positive duty cycle,current density and frequency.Good corrosion resistance coating is obtained when the current density is 22 A/dm2,positive duty cycle is 40%,treating time is 12 min and frequency is 500 Hz.Compared with the Mg alloy substrate,the corrosion potential of the coated sample increases by 36.4 mV,and the corrosion current density of the coated sample decreases one order of magnitude.

Field of study: Materials science
Separation of Ionization Traps in NPN Transistors Irradiated by Lower Energy Electrons

Effects of oxide-trapped charge and interface traps induced by ionizing radiation, on the degradation of the electrical properties in NPN bipolar junction transistors (BJTs), are identified in this paper. Ionization traps in 3DG110 NPN BJTs are caused by 110 keV electron irradiations for various fluences, and the key electrical parameters are measured in situ during irradiation. In order to separate the effects of the interface traps and oxide charge on the radiation response in BJTs, the isochronal and isothermal annealing are performed after irradiations. Behavior of the radiation-induced defects is detected by DLTS after the irradiation and the postirradiation annealing. Measurement results indicate that when the change in reciprocal of the gain (Δ(1/ β)) tends to level off, the concentration of oxide-trapped charge increases with increasing irradiation fluence, while that of the interface traps keeps unchangeable. A comparison of DLTS signals with changes in excess base current (ΔIB) versus base-emitter voltage (VBE) is conducted to show the role of oxide-trapped charge and interface traps on the excess base current, illustrating that the DLTS analysis is suitable to separate the ionization traps in BJTs.

Field of study: Physics
ANEL: A novel efficient and lightweight authentication scheme for vehicular ad hoc networks

Due to the large traffic congestion in modern-day, Vehicular Ad Hoc Network (VANET) becomes an important approach to improve human safety and driving comfort. The large traffic congestion increases the number of transmitted messages, which in turn increases the computations and communications overheads in VANET. Hence, VANET requires not only efficient communications, but also lightweight security mechanisms to overcome security challenges. There are many schemes provide security to VANET by using cryptography techniques such as elliptic curve technique, session key technique, public key technique, and message authentication code technique. The schemes that use the message authentication code are called MAC-based authentication schemes. They considered as the best schemes in terms of computation and communication overheads when compared with other schemes that use other cryptography techniques, but they have some limitations. This paper proposes a novel efficient and lightweight authentication scheme (ANEL). The ANEL is a MAC-based authentication scheme that offers all the advantages of the MAC-based authentication schemes and overcomes all their limitations at the same time. In addition, the proposed scheme can achieve security objectives of VANET such as authentication, privacy-preservation, non-repudiation, etc. Moreover, our scheme provides an efficient biological password login, system key update, biological password update, and other security services. Furthermore, in this proposed scheme, the Trust Authority (TA) can disclose the source driver and vehicle of each malicious message. The security analysis shows that ANEL is the first scheme that provides countermeasures on the disclosure of system key, and it can protect VANET from various well-known attacks. The comparison results of our scheme with existing MAC-based authentication schemes in terms of computation overhead, communication overhead, and security services show that the proposed scheme is more efficient and provides a high level of security. The simulation results with ONE simulator demonstrate that our scheme reduces the message authentication time and end-to-end delay when compared with previous security schemes discussed in the literature.

Field of study: Computer science
Structural characterization of the N‐terminal part of the MERS‐CoV nucleocapsid by X‐ray diffraction and small‐angle X‐ray scattering

The N protein of coronaviruses is a multifunctional protein that is organized into several domains. The N‐terminal part is composed of an intrinsically disordered region (IDR) followed by a structured domain called the N‐terminal domain (NTD). In this study, the structure determination of the N‐terminal region of the MERS‐CoV N protein via X‐ray diffraction measurements is reported at a resolution of 2.4 Å. Since the first 30 amino acids were not resolved by X‐ray diffraction, the structural study was completed by a SAXS experiment to propose a structural model including the IDR. This model presents the N‐terminal region of the MERS‐CoV as a monomer that displays structural features in common with other coronavirus NTDs.

Field of study: Chemistry
The Third Sector and Residential Care for the Elderly in China's Transitional Welfare Economy

This article examines third-sector welfare homes for Chinese elderly and argues that four factors affect their survival and development prospects: the extent care establishments meet the needs of their users; how successfully they manage their human resources; whether they ensure their financial sustainability; and whether they satisfy the expectations of their investors. The data reveal that while care homes generally serve their customers well and maintain staff satisfaction, they encounter difficulties in financing and service operation that pose grave challenges to their investors. The resulting problems cast a shadow over the future prospects of old-age care homes and raise questions concerning the state's non-profit policy.

Field of study: Political science
A martingale characterization of the price of a nonrenewable resource with decisions involving uncertainty

This paper presents a general model of nonrenewable resource consumption and exploration decisions involving uncertainty about the time of occurrence of an event such as exhaustion, stock discovery, or a substitute development. The resulting price process is characterized in terms of necessary and sufficient conditions under which the price is expected to rise at a rate equal to, greater than, or less than the discount rate. The general model is illustrated and the price process and the optimal decisions are characterized by examining the three types of uncertainty indicated above.

Field of study: Economics
Geology, lithogeochemistry, and significance of porphyry intrusions associated with gold mineralization within the Timmins–Porcupine gold camp, Canada

The Timmins–Porcupine gold camp, Abitibi greenstone belt, is host >60 Moz of Au with many gold deposits spatially associated with porphyry intrusions and the Porcupine–Destor deformation zone (PDDZ...

Field of study: Environmental science
An inverse time-dependent source problem for a time-space fractional diffusion equation

This paper is devoted to identify a time-dependent source term in a time–space fractional diffusion equation by using the usual initial and boundary data and an additional measurement data at an inner point. The existence and uniqueness of a weak solution for the corresponding direct problem with homogeneous Dirichlet boundary condition are proved. We provide the uniqueness and a stability estimate for the inverse time-dependent source problem. Based on the separation of variables, we transform the inverse source problem into a first kind Volterra integral equation with the source term as the unknown function and then show the ill-posedness of the problem. Further, we use a boundary element method combined with a generalized Tikhonov regularization to solve the Volterra integral equation of the fist kind. The generalized cross validation rule for the choice of regularization parameter is applied to obtain a stable numerical approximation to the time-dependent source term. Numerical experiments for six examples in one-dimensional and two-dimensional cases show that our proposed method is effective and stable.

Field of study: Mathematics