nils-herrmann/clean_scirepeval huggingface dataset:
Radioactivation analysis in a nuclear reactor

The factors affecting the sensitivity of radioactivation analysis are analyzed and the technique is described and discussed. The flux and cross sections are not usually known well enough, so a weighed quantity of the element studied is irradiated simultaneously for calibration purposes. After activation two possible procedures may be used. For short-lived products, spectrometry can be applied directly. For other products a chemical separation is necessary before spectrometry because of the residual activity of the main bulk of the sample. Important sources of error, such as from neutron absorption by the sample, must be considered. The use of fast as well as slow fluxes is of some value in certain determinations. The advantages and disadvantages of the radioactivation method are pointed out.

Field of study: Chemistry
Temporal sequence of metabolic and ionic events in glucose-stimulated clonal pancreatic beta-cells (HIT).

Stimulation of insulin release by glucose requires increased metabolism of glucose and a rise in cytosolic free Ca2+ in the pancreatic beta-cell. It is accompanied by increases in respiratory rate, pyridine and flavin nucleotide reduction state, intracellular pH and the ATP/ADP ratio. To test alternative proposals of the regulatory relationships among free Ca2+, mitochondrial metabolism and cellular energy state, we determined the temporal sequence of these metabolic and ionic changes following addition of glucose to clonal pancreatic beta-cells (HIT). Combined measurements of the native fluorescence of reduced pyridine nucleotides and oxidized flavin, intracellular pH, and free Ca2+ were performed together with simultaneous measurement of O2 tension or removal of samples for assay of the ATP/ADP ratio. The initial changes were detected in three phases. First, decreases occurred in the ATP/ADP ratio (<3 s) and increases in pyridine (2 +/- 1 s) and flavin (2 +/- 1 s) nucleotide reduction. Next, increases in the O2 consumption rate (20 +/- 5 s), the ATP/ADP ratio (29 +/- 12 s) and internal pH (48 +/- 5 s) were observed. Finally, cytosolic free Ca2+ rose (114 +/- 10 s). Maximal changes in the ATP/ADP ratio, O2 consumption and pyridine and flavin nucleotide fluorescence preceded the beginning of the Ca2+ change. These relationships are consistent with a model in which phosphorylation of glucose is the initial event which generates the signals that lead to an increase in respiration, a rise in the ATP/ADP ratio and finally influx of Ca2+. Our results indicate that Ca2+ does not function as the initiator of increased mitochondrial respiration.

Field of study: Biology, Computer science
Oxygen isotope values from high-latitudes: Clues for Permian sea-surface temperature gradients and Late Palaeozoic deglaciation

The Permian was a period of waning large-scale continental glaciations in the southern Hemisphere. The waning of these ice sheets during the Early Permian led to discharge of 18O-depleted ice–melt water into the oceans. This, coupled with rising seawater temperatures, resulted in a concomitant decline of about 2.5‰ in the δ18O of seawater, as recorded by brachiopod shells from low-latitude (

Field of study: Environmental science, Geography
Study on the Protective Enzyme Activity of the Hevea Seedling Under Low Phosphorus Stress

By the hydroponic culture method,the effect of low phosphorus stress on the protective enzyme system of Hevea seedlings were studied.The results showed that MAD content and SOD activities were increased under the low phosphorus stress,and higher than the CK in 84 days;POD,CAT activities began to increasing in 42 days,and both higher than CK at the 42nd day,decreased in 42～84 days and lower than the CK at the 84th Day.MAD content was changed in the roots less than in other organs,while the SOD,POD and CAT activities changed a lot more than in other organs.Root was much more sensitive by the low phosphorus stress than other organs.

Field of study: Agricultural and Food sciences
Molecular differentiation of schizoaffective disorder from schizophrenia using BDNF haplotypes.

Allelic variation in the gene encoding brain-derived neurotrophic factor (BDNF) has been associated with affective disorders, but generally not schizophrenia. Brain-derived neurotrophic factor variants may help clarify the status of schizoaffective disorder.



To test the hypothesis that BDNF haplotypes are associated with psychiatric illness marked by a prominent affective component.



Frequencies of a 5-marker BDNF haplotype were examined in 600 White participants across four diagnostic categories and healthy controls.



Individuals with schizoaffective disorder and other affective disorders were significantly more likely to carry two copies of the most common BDNF haplotype (containing the valine allele of the Val66Met polymorphism) compared with healthy volunteers. Moreover, when compared with people with schizophrenia, individuals with schizoaffective disorder were significantly more likely to carry two copies of the common haplotype.



To our knowledge, this is the first candidate gene study to demonstrate association with schizoaffective disorder but not schizophrenia. Variation in the BDNF gene may be associated with the clinical phenotype of affective dysregulation across several DSM-IV diagnostic categories.

Field of study: Medicine, Psychology
A practical language and toolkit for high-integrity tools

This paper shows how a safe interface to heap storage, based on garbage collection as provided in implementations of pure functional languages, can be combined with imperative languages. It also shows how expressive notation from functional languages, such as algebraic data types and equational definition of functions with pattern matching, can be adopted. The paper argues that the resulting combination is appropriate for the construction of high-integrity tools, based on an assessment against the same criteria as have been used for assessing the suitability of imperative languages for producing high-integrity software.

Field of study: Computer science, Engineering
Simulated Design Strategies for SPECT Collimators to Reduce the Eddy Currents Induced by MRI Gradient Fields

Combining single photon emission computed tomography (SPECT) with magnetic resonance imaging (MRI) requires the insertion of highly conductive SPECT collimators inside the MRI scanner, resulting in an induced eddy current disturbing the combined system. We reduced the eddy currents due to the insert of a novel tungsten collimator inside transverse and longitudinal gradient coils. The collimator was produced with metal additive manufacturing, that is part of a microSPECT insert for a preclinical SPECT/MRI scanner. We characterized the induced magnetic field due to the gradient field and adapted the collimators to reduce the induced eddy currents. We modeled the x-, y-, and z-gradient coil and the different collimator designs and simulated them with FEKO, a three-dimensional method of moments / finite element methods (MoM/FEM) full-wave simulation tool. We used a time analysis approach to generate the pulsed magnetic field gradient. Simulation results show that the maximum induced field can be reduced by 50.82% in the final design bringing the maximum induced magnetic field to less than 2% of the applied gradient for all the gradient coils. The numerical model was validated with measurements and was proposed as a tool for studying the effect of a SPECT collimator within the MRI gradient coils.

Field of study: Physics
Multi-channel MAC Protocol of Wireless Mesh Networks Based on Directional Antennas and Time Synchronization Mechanism

It's of imminent importance to build wireless mesh networks as access networks for wireless users in city districts and countryside.This paper describes in detail a new MAC protocol,called Mesh-MAC,that is suited for such networks in terms of efficiency.The protocol is implemented on top of low-cost 802.11 hardware.By a novel network time synchronization mechanism,we realize packet-forwarding in the network based on per link forwarding that is formed by directional antennas.The simulation results indicate that Mesh-MAC protocol achieves much improvement in performance such as throughput and end-to-end delay etc.compared with 802.11 and 2P protocols.

Field of study: Computer science
Epirogenese in Nordwestdeutschland im höheren Jura und in der Unterkreide

ZusammenfassungDie epirogenen Vorgänge, die in Nordwestdeutschland im höheren Jura und in der Unterkreide stattgefunden haben, werden in drei Karten dargestellt und im Text erörtert. Vorbedingung hierfür war die Möglichkeit der Trennung des epirogenen und des halokinetischen Anteils an den jeweiligen Bodenbewegungen.AbstractEpeirogenic movements, which happened in Northwest-Germany in later Jurassic and in lower Cretaceous time are mapped and discussed. Preliminary condition for this was the possibility of separating the epeirogenic and the halokinetic part of the movements.RésuméLes événements épirogénétiques qui se sont produits dans la partie supérieure du Jurassique et au Crétacé inférieur en Allemagne du Nord-Ouest sont discutés et représentés sous forme de cartes. La condition préliminaire pour cela était la possibilité de séparer les mouvements épirogénétiques et les mouvements halokinétiques.Краткое содержаниеНа трех картах предст авлены и пояснены в те ксте эпирогенные процесс ы, имевшие место в север о-западной Германии в верхней Юре и в нижнем меле. Предпосы лкой послужило разгр аничение эпирогенных и галокинетических эл ементов в каждом данн ом движении.

Field of study: Environmental science
A deflation method for regular matrix pencils

A generalization of the concept of eigenvalue is introduced for a matrix pencil and it is called eigenpencil; an eigenpencil is a pencil itself and it contains part of the spectral information of the matrix pencil. A Wielandt type deflation procedure for regular matrix pencils is developed, using eigenpencils and supposing that they can have both finite and infinite eigenvalues. A numerical example illustrates the proposed method.

Field of study: Mathematics
Electron Transfer Capacities of Dissolved Organic Matter Derived from Swine Manure Based on Eletrochemical Method

Dissolved organic matter (DOM) is the most active fraction of compost organic matter. The presence of the redox-active functional groups in DOM allows it to act an electron shuttle to promote the electron transfer between microorganisms and terminal electron acceptors. In this study, the electron transfer capacities (ETCs) of compost DOM samples at eight different composting stages were determined by electrochemical method. 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and Diquat dibro-mide monohydrate (DQ) were used to measured electron donating capacity (EDC) and electron accepting capacity (EAC) at working voltage 0.61 V/–0.49 V, respectively. The evolution characteristics of the chemical structures and components were analyzed by combining the three-dimensional fluorescence spectra, Fourier transform infrared (FTIR) spectra and elemental analysis. The results showed that the EDC of DOM increased from 16.850 μmol e− (g C)−1 to 22.077 μmol e− (g C)−1, The EAC decreased from 1.866 μmol e− (g C)−1 to 1.779 μmol e− (g C)−1. The results of three-dimensional fluorescence spectroscopy showed that the relative contents of humic-like and protein-like components gradually increased and decreased, respectively, during the composting process. The humuc-like components were the main contributor for the ETC of DOM. FTIR spectra showed that there was no significant change in the hydroxyl and carboxyl group contents of DOM during composting, suggesting no contribution of these function groups to the ETC of DOM. The elemental analysis showed that the content of oxygen in the DOM increased during the composting process, while the sulfur-containing group might be dominated contributor for its ETC.

Field of study: Chemistry
Dunnigan-Kobberling syndrome: an autosomal dominant form of partial lipodystrophy.

Dunnigan-Kobberling syndrome is a form of partial lipodystrophy characterized by sparing of the face. Despite descriptions of six families since 1974, details of total body adipose tissue distribution and studies of carbohydrate and fat metabolism are lacking. The mode of inheritance also remains unclear, with most authors favouring an X-linked dominant transmission lethal in the hemizygous male. We examined 23 members of a family, of whom at least eight had partial lipodystrophy. Auxological evaluation and cross-sectional imaging showed absence of subcutaneous fat, presence of adipose tissue inside the body cavities, and skeletal muscle hypertrophy. Biochemical evaluation identified insulin resistance but revealed inadequate suppression of non-esterified fatty acids. In this family, male-to-male transmission supports an autosomal dominant mode of inheritance for Dunnigan-Kobberling syndrome.

Field of study: Medicine
The Tarantula Nebula as a template for extragalactic star forming regions from VLT/MUSE and HST/STIS

We present VLT/MUSE observations of NGC 2070, the dominant ionizing nebula of 30 Doradus in the LMC, plus HST/STIS spectroscopy of its central star cluster R136. Integral Field Spectroscopy (MUSE) and pseudo IFS (STIS) together provides a complete census of all massive stars within the central 30×30 parsec2 of the Tarantula. We discuss the integrated far-UV spectrum of R136, of particular interest for UV studies of young extragalactic star clusters. Strong He iiλ1640 emission at very early ages (1–2 Myr) from very massive stars cannot be reproduced by current population synthesis models, even those incorporating binary evolution and very massive stars. A nebular analysis of the integrated MUSE dataset implies an age of ~4.5 Myr for NGC 2070. Wolf-Rayet features provide alternative age diagnostics, with the primary contribution to the integrated Wolf-Rayet bumps arising from R140 rather than the more numerous H-rich WN stars in R136. Caution should be used when interpreting spatially extended observations of extragalactic star-forming regions.

Field of study: Physics
Small and Medium Tourist Enterprises and Social Media Adoption: Empirical Evidence from Tanzanian Tourism Sector

The increasing competition and the highly demands of globalization in tourism sector are increasing challenges in the market and operation of Small and Medium enterprises in Tanzania. In order to cope with these challenges, it is evidenced that the adoption of social media networking is an enabler of small and medium tourist enterprises in quest of enhancing competitiveness in their globalized market place. Despite of this benefit offered by Social Media (SM) to SMEs, very little is known on the factors influencing adoption of Social Media in Tanzanian Tourist sector. This paper aims at filling the gap by examining factors influencing adoption of Social Media Networking among SMEs in Tanzanian Tourism Sector. Questionnaire was used to collect data from SMEs owners and employees in Dar es salaam city, Iringa region and Rukwa region where geographical stratified sampling was used to ensure representativeness of the sample from the heterogonous population to form homogeneous group followed by simple random sampling technique which was used to draw a sample of 265 respondents for quantitative data and purposive sampling technique was used to pick sample for qualitative data. Factor analysis was used to ensure construct validity of the proposed conceptual model in this study while Cronbach’s alpha was used to test the suitability of research instrument used in collecting data for the study. Structure equation modeling method was used to test hypothesis on the factors influencing adoption of social media networking among SME in Tanzania tourism sector. Findings using SEM revealed that organization context and environmental context are significantly influencing adoption of social media networking adoption while technology context was found to be insignificant factor. This study recommended that in order SMEs to continuously be competitive in this global and dynamic market they should continue to adopt the use of social media networking as a tool to capture more customers worldwide.

Field of study: Business
Genome-wide DNA methylation alterations of Alternanthera philoxeroides in natural and manipulated habitats: implications for epigenetic regulation of rapid responses to environmental fluctuation and phenotypic variation.

Alternanthera philoxeroides (alligator weed) is an invasive weed that can colonize both aquatic and terrestrial habitats. Individuals growing in different habitats exhibit extensive phenotypic variation but little genetic differentiation in its introduced range. The mechanisms underpinning the wide range of phenotypic variation and rapid adaptation to novel and changing environments remain uncharacterized. In this study, we examined the epigenetic variation and its correlation with phenotypic variation in plants exposed to natural and manipulated environmental variability. Genome-wide methylation profiling using methylation-sensitive amplified fragment length polymorphism (MSAP) revealed considerable DNA methylation polymorphisms within and between natural populations. Plants of different source populations not only underwent significant morphological changes in common garden environments, but also underwent a genome-wide epigenetic reprogramming in response to different treatments. Methylation alterations associated with response to different water availability were detected in 78.2% (169/216) of common garden induced polymorphic sites, demonstrating the environmental sensitivity and flexibility of the epigenetic regulatory system. These data provide evidence of the correlation between epigenetic reprogramming and the reversible phenotypic response of alligator weed to particular environmental factors.

Field of study: Environmental science
A Novel Molecular System for Nitric Oxide Detection with High Sensitivity

A novel molecular switching system was developed for the direct detection of endogenous nitric oxide. The system is comprised from an Fe(II)–dithiocarbamate complex in which TEMPOL molecule coordinates to the centered iron through a redox interaction. Nitric oxide binds to the iron to liberate the TEMPOL. The system will be potentially useful for the monitoring of endogenous nitric oxide.

Field of study: Chemistry
On the convergence of a damped Newton-like method with modified right hand side vector

We present a convergence analysis for a damped Newton-like method with modified right-hand side vector in order to approximate a locally unique solution of a nonlinear equation in a Banach spaces setting. In the special case when the method is defined on R m , our method provides computable error estimates based on the initial data. Such estimates were not given in relevant studies such as. Numerical examples further validating the theoretical results are also presented in this study.

Field of study: Mathematics
Effect of environment on the early steps of ear initiation in maize (Zea mays L.)

The effects of environmental conditions on ear-shoot initiation have been investigated in three inbred genotypes of Zea mays L. which are used for seed production. Scanning electron microscopy (SEM) and binocular examination during the vegetative phase showed that axillary meristems are initiated at the same rate as the leaf primordia on the apical meristem, but with a delay of 5.6-7.0 plastochrons, depending on the genotype. Furthermore, the topmost axillary meristem is initiated on the same day as the tassel, whatever the genotype. One of the inbreds (B22) used in this study has been reported to exhibit, in field conditions, a reproductive failure affecting ear initiation, causing the topmost ear to be replaced at maturity by a sterile, leaf-like, structure. Scanning electron microscopic study of the formation of the abnormal axillary buds indicated that ear failure resulted from the early collapse of the axillary meristem followed by elongation of the prophyll or of the meristem itself. Using controlled environments, ear abortion was mimicked by a chilling treatment (10 degrees C), given just before tassel initiation. Other factors, such as high irradiance and flooding, enhanced the abortive response. The critical stage for the main ear was just before the initiation of the topmost axillary meristem which also corresponded to tassel initiation. Chilling the plants before or after tassel initiation either induced an acclimation response or had no effect. The three inbreds showed differential responses to the stress treatment, indicating that a genetic factor is implicated as well. It is suggested that chilling causes a perturbation of apical dominance which, in the responsive genotypes, represses axillary meristem development. The use of a stress-sensitive inbred such as B22 as a model system could yield some interesting clues to the mechanism of endogenous control of ear initiation in maize.

Field of study: Environmental science
A Case Study of Implementing a Cooperative Learning Program in an Inner-City School

Although there is substantial research on the benefits of cooperative learning strategies, little is known about how teachers implement these strategies under typical school conditions. The purpose of the present case study was to exam ine the implementation process for 9 teachers at 1 elementary school during a full year. Qualitative and quantitative measures included systematic classroom observa tion, teacher questionnaires, interviews, and informal contacts with the principal and teachers. The major finding of the study was that most teachers became increas ingly proficient over the year at implementing 1 type of cooperative learning (STAD?Student Teams-Achievement Divisions), but considerable planning and monitoring were needed to ensure their success. Over time, teachers tended to become increasingly satisfied and comfortable in using STAD; associated outcomes were moderately high levels of student collaboration and interdependence during the cooperative learning sessions. However, despite these outcomes, many of the teach ers struggled throughout the year to understand and implement the specific strate gies prescribed by the STAD model. Three emergent themes related to these strug gles?training, administrative support, and peer encouragement?emerged from the study. Each seems critical to the quality of the classroom implementations of STAD that were achieved.

Field of study: Education
Semiparametric Estimation for Two-Sample Location-Scale Models under Type I Censorship

To compare two samples under Type I censorship, this article proposes a method of semiparametric inference for the two-sample location-scale problem when the model for two samples is characterized by an unknown distribution and two unknown parameters. Simultaneous estimators for both the location shift and scale change parameters are given. It is shown that the two estimators are strongly consistent and asymptotically normal. The approach in this article can also be used for scale-shape models. Monte Carlo studies indicate that the proposed estimation procedure performs well in finite and heavily censored samples, maintains high relative efficiencies for a wide range of censoring proportions and is robust to the model misspecification, and also outperforms other competitive estimators.

Field of study: Mathematics