bluuebunny/crossref_metadata_2025 huggingface dataset:
UNDERSTANDING THE EFFECT OF CO-WORKER SUPPORT ON CONSTRUCTION SAFETY PERFORMANCE FROM THE PERSPECTIVE OF RISK THEORY: AN AGENT-BASED MODELING APPROACH
Authors: Ji Tingting , Wei Hsi-Hsien , Chen Jiayu
Published: February 2019

Co-worker safety support has been given prominence in manufacturing and transportation field for its positive effect on individual workers’ safety; however, there is little evidence to show if such supporting role of co-workers is significant in improving project-level safety performance in construction workplace. This study adopts agent-based modeling (ABM) to understand the effectiveness of two distinct co-worker-safety-support actions on the safety performance of a construction project. Based on the risk theory, the ABM model simulates a construction site where worker agents reinforce steel bars with the likelihood of suffering crane-related incidents. The results indicate that both co-worker-support actions can significantly reduce the occurrence of nonfatal incidents but shows little influence in fatal incidents, and in reducing high-severity incidents, the action of warning peers to leave the hazardous area has the same effectiveness as reminding peers to wear Personal Protective Equipment. The present study provides a fresh insight into the safety-related role of co-workers: not only reveals how the local-level effects of co-workers’ safety assistance emerge the system-level consequences, but demonstrates the effectiveness of specific peer-support actions on three levels of construction safety performance, and thereby extends our existing body of knowledge on co-worker safety support in the construction field.
Reference Star Differential Imaging of Close-in Companions and Circumstellar Disks with the NIRC2 Vortex Coronagraph at the W. M. Keck Observatory
Authors: Ruane Garreth , Ngo Henry , Mawet Dimitri , Absil Olivier , Choquet Élodie , Cook Therese , Gonzalez Carlos Gomez , Huby Elsa , Matthews Keith , Meshkat Tiffany , Reggiani Maddalena , Serabyn Eugene , Wallack Nicole , Xuan W. Jerry
Published: February 2019

Reference star differential imaging (RDI) is a powerful strategy for high-contrast imaging. Using example observations taken with the vortex coronagraph mode of Keck/NIRC2 in L′ band, we demonstrate that RDI provides improved sensitivity to point sources at small angular separations compared to angular differential imaging (ADI). Applying RDI to images of the low-mass stellar companions HIP 79124 C (192 mas separation, ΔL′ = 4.01) and HIP 78233 B (141 mas separation, ΔL′ = 4.78), the latter a first imaging detection, increases the significance of their detections by up to a factor of 5 with respect to ADI. We compare methods for reference frame selection and find that pre-selection of frames improves detection significance of point sources by up to a factor of 3. In addition, we use observations of the circumstellar disks around MWC 758 and 2MASS J16042165−2130284 to show that RDI allows for accurate mapping of scattered light distributions without self-subtraction artifacts.
Double-decker Filament Configuration Revealed by Mass Motions
Authors: Awasthi Arun Kumar , Liu Rui , Wang Yuming
Published: February 2019

It is often envisaged that dense filament material lies in the dips of magnetic field lines belonging to either a sheared arcade or a magnetic flux rope. But it is also debated which configuration correctly depicts filaments’ magnetic structure, due to our incapacity to measure the coronal magnetic field. In this paper, we address this issue by employing mass motions in an active-region filament to diagnose its magnetic structure. The disturbance in the filament was driven by a surge initiated at the filament’s eastern end in the NOAA active region 12685, which was observed by the 1 m New Vacuum Solar Telescope in the Hα line-center and line wing (±0.4 Å). Filament material predominately exhibits two kinds of motions, namely, rotation about the spine and longitudinal oscillation along the spine. The former is evidenced by antisymmetric Doppler shifts about the spine; the latter features a dynamic barb with mass extending away from the Hα spine until the transversal edge of the EUV filament channel. The longitudinal oscillation in the eastern section of the filament is distinct from that in the west, implying that the underlying field lines have different lengths and curvature radii. The composite motions of filament material suggest a double-decker host structure with mixed signs of helicity, comprising a flux rope atop a sheared-arcade system.
Acceleration of Cosmic Rays in Supernova Shocks: Elemental Selectivity of the Injection Mechanism
Authors: Hanusch Adrian , Liseykina Tatyana V. , Malkov Mikhail
Published: February 2019

Precise measurements of galactic cosmic rays revealed a significant difference between the rigidity spectral indices of protons and helium ions. This finding is a notable contrast to the commonly accepted theoretical prediction that supernova remnant (SNR) shocks accelerate protons and helium ions with the same rigidity alike. Most of the earlier explanations for the “paradox” appealed to SNR environmental factors, such as inhomogeneous p/He mixes in the shock upstream medium, variable ionization states of He, or a multi-SNR origin of the observed spectra. The newest observations, however, are in tension with most past models. In this paper, we show by self-consistent hybrid simulations that such special conditions are not vital for explaining the cosmic-ray rigidity spectra. In particular, our simulations prove that an SNR shock can modify the chemical composition of accelerated cosmic rays by preferentially extracting them from a homogeneous background plasma without additional, largely untestable assumptions. Our results confirm the earlier theoretical predictions of how the efficiency of injection depends on the shock Mach number M. Its increase with the charge-to-mass ratio saturates at a level that grows with M. We have convolved the time-dependent injection rates of protons and helium ions, obtained from the simulations, with a decreasing shock strength over the active lives of SNRs. The integrated SNR rigidity spectrum for p/He ratio compares well with the AMS-02 and PAMELA data.
Chemical Network Reduction in Protoplanetary Disks
Authors: Xu Rui , Bai Xue-Ning , Öberg Karin , Zhang Hao
Published: February 2019

Protoplanetary disks (PPDs) are characterized by different kinds of gas dynamics and chemistry, which are coupled via ionization, heating, and cooling processes, as well as advective and turbulent transport. However, directly coupling gas dynamics with time-dependent chemistry is prohibitively computationally expensive when using comprehensive chemical reaction networks. In this paper, we evaluate the utility of a species-based network reduction method in different disk environments to produce small chemical networks that reproduce the abundances of major species found in large gas-phase chemistry networks. We find that the method works very well in disk midplane and surface regions, where approximately 20–30 gas-phase species, connected by ∼50–60 gas-phase reactions, are sufficient to reproduce the targeted ionization fraction and chemical abundances. Most species of the reduced networks, including major carriers of oxygen, carbon and nitrogen, also have similar abundances in the reduced and complete network models. Our results may serve as an initial effort for future hydrodynamic/magnetohydrodynamic simulations of PPDs incorporating time-dependent chemistry in appropriate regions. Accurately modeling the abundances of major species at intermediate disk heights, however, will require a much more extended network incorporating gas-grain chemistry and is left for future studies.
On the Bimodal Spin-period Distribution of Be/X-Ray Pulsars
Authors: Xu Xiao-Tian , Li Xiang-Dong
Published: February 2019

It has been reported that there are two populations of Be/X-ray pulsars, with the pulse period distribution peaked at ∼10 s and ∼200 s, respectively. A possible explanation of this bimodal distribution is related to different accretion modes in Be/X-ray binaries. In this work, we investigate the spin evolution of Be/X-ray pulsars based on the magnetically threaded accretion disk model. Compared with previous works, we take into account several distinct and important factors of Be/X-ray binaries, including the transient accretion behavior and possible change of the accretion disk structure during quiescence. We demonstrate that current Be/X-ray pulsars are close to the spin equilibrium determined by the balance of spin-up during outbursts and spin down during quiescence, and that the observed bimodal distribution can be well reproduced by the equilibrium spin periods with reasonable input parameters.
New Models of Jupiter in the Context of Juno and Galileo
Authors: Debras Florian , Chabrier Gilles
Published: February 2019

Observations of Jupiter’s gravity field by Juno have revealed surprisingly low values for the high-order gravitational moments, considering the abundances of heavy elements measured by Galileo 20 years ago. The derivation of recent equations of state for hydrogen and helium, which are much denser in the megabar region, exacerbates the conflict between these two observations. In order to circumvent this puzzle, current Jupiter model studies either ignore the constraint from Galileo or invoke an ad hoc modification of the equations of state. In this paper, we derive Jupiter models that satisfy constraints of both Juno and Galileo. We confirm that Jupiter’s structure must encompass at least four different regions: an outer convective envelope, a region of compositional and thus entropy change, an inner convective envelope, an extended diluted core enriched in heavy elements, and potentially a central compact core. We show that in order to reproduce Juno and Galileo observations, one needs a significant entropy increase between the outer and inner envelopes and a lower density than for an isentropic profile, which is associated with some external differential rotation. The best way to fulfill this latter condition is an inward-decreasing abundance of heavy elements in this region. We examine in detail the three physical mechanisms that can yield such a change of entropy and composition: a first-order molecular-metallic hydrogen transition, immiscibility between hydrogen and helium, or a region of layered convection. Given our present knowledge of hydrogen pressure ionization, a combination of the two latter mechanisms seems to be the most favored solution.
The PPEAO experimental fishing dataset: Fish from West African estuaries, lagoons and reservoirs
Authors: Simier Monique , Ecoutin Jean-Marc , Tito de Morais Luis
Published: February 2019

This paper describes a dataset of fish, crustacean and mollusc occurrences extracted from the “Experimental Fishing” section of the IRD's PPEAO information system. PPEAO stands for “Fish communities and artisanal fisheries of West African estuarine, lagoon and freshwater ecosystems”. This database contains information collected using two different methods: experimental fishing and surveys of the artisanal fisheries that exploit these ecosystems. The database is accessible at http://ppeao.ird.fr.

The current dataset is available on GBIF.org at 10.15468/ra4voa. It comprises the occurrences of 314 fish, crustacean and mollusc taxa collected in experimental sampling surveys of different aquatic ecosystems in West Africa between 1979 and 2013. Different types of fishing gear were used including purse seines, gill nets and fyke nets. The taxa were identified by IRD scientists or by scientific partners well trained in systematics. Most taxa were identified at species level (97% of cases). This dataset is the result of 213 fishing surveys, 5,362 fishing hauls and 31,709 occurrences (28,428 of fish taxa and 3,281 of crustaceans and molluscs). The number of individuals per species and per haul is included and 80% of occurrences are geolocated.
La contingence des actions du Conseil de sécurité des Nations unies dans la protection des droits de l’homme
Authors: Moine André
Published: February 2019

Les membres des Nations unies ont conféré au Conseil de sécurité la mission principale du maintien de la paix et de la sécurité internationales. Dans le cadre de cette mission pacificatrice des relations internationales, le Conseil peut potentiellement protéger, promouvoir ou respecter les droits de l’homme et les libertés fondamentales. Un lien doit à cette fin être établi entre la paix et le respect des droits de l’homme. Cependant, la latitude d’action du Conseil de sécurité pour agir en faveur des droits de l’homme suppose l’existence de situations susceptibles de justifier son action pour leur défense ou leur promotion et la réunion de conditions politiques internationales favorables à l’adoption de résolutions pour tenter d’y remédier. Une telle intervention du Conseil en faveur des droits de l’homme peut être motivée soit parce que la méconnaissance ou la violation de ces derniers nuit à la sécurité internationale soit parce que la promotion des droits de l’homme est un moyen d’établissement et de consolidation de la paix. L’étendue des droits ainsi promus ou défendus dans les différentes situations est un enjeu parallèle de cette volonté du Conseil. Cependant encore, malgré un unanimisme du discours sur le nécessaire respect des droits de l’homme et la large ratification des instruments juridiques les recensant, les dissensions relatives aux moyens de ce respect par le Conseil sont fréquentes en son sein. Certains membres refusent la prise en compte des atteintes aux droits de l’homme par le Conseil de sécurité car celles-ci relèveraient de la souveraineté nationale ou d’autres enceintes. Ils soupçonnent en effet une possible instrumentalisation politique des atteintes aux droits de l’homme. D’autres membres, à l’inverse, considèrent que la protection des droits de l’homme est indissociable de la paix et de la sécurité internationales. De plus, en pratique, la légitimité du Conseil de sécurité à agir en la matière est parfois, sinon souvent, contestée notamment du fait de la composition même du Conseil, de la manière dont il exerce son mandat et de ses propres défaillances dans le respect des droits de l’homme. Ces écueils nuisent à l’aptitude du Conseil de sécurité des Nations unies à agir effectivement ou systématiquement pour protéger les droits de tous les membres de la communauté humaine.
Top 100 Most-Cited Clinical Studies of Hip and Knee Arthroplasty: The Foundation of Practice
Authors: Piuzzi Nicolas S. , Sultan Assem A. , Gatta Julian , Ng Mitchell , Cantrell William A. , Khlopas Anton , Newman Jared M. , Sodhi Nipun , Harwin Steven F. , Mont Michael A.
Published: February 2019

Total number of citations has been considered a proxy for a published study's importance within a given field. However, there are multiple pitfalls to correlating the total number of citations alone with the quality of a study. In this review, the authors aimed to identify the top 100 most-cited studies of hip and knee arthroplasty and then assess study design and quality of reporting. More than half of these studies were level IV evidence, unblinded, not randomized, and not controlled. This underscores the need for higher-quality study design to support practice. [
Orthopedics
. 2019; 42(2):e151–e161.]
Carbonation of hybrid concrete with high blast furnace slag content and its impact on structural steel corrosion
Authors: Angulo-Ramirez D. E. , Mejía de Gutiérrez R. , Valencia-Saavedra W. G. , De Medeiros M. H. F. , Hoppe-Filho J.
Published: February 2019

The aim of this research was to study the carbonation resistance of a blast furnace slag concrete (80% GBFS/20%OPC), with and without alkaline activation, and its influence on the corrosion of structural reinforcement. An OPC-based concrete produced under the same specifications was used as a reference material. To do this, the material was subjected to an accelerated carbonation process under controlled conditions (65% relative humidity, 1% CO2, 25°C). The half-cell potential (Ecorr), linear polarization resistance (LPR) tests showed that both concretes based on GBFS led to depassivation of the reinforcing steel at approximately 99 days, which is the time required for full carbonation of the evaluated concretes.
Size effect in the fracture properties of sandwich panels of plasterboard and core of rock wool
Authors: Alonso J. A. , Reyes E. , Gálvez J. C.
Published: February 2019

This paper extends the previous work of the authors and deals with the study of fracture of sandwich panels of plasterboard and rock wool under in-plane bending and tensile loading. It presents the results of the experimental campaign focused on the size effect of the tested specimens. To this end, mixed-mode (I and II) fracture tests have been carried out with specimens of three different sizes. The experimental results are compared with the values obtained from the numerical simulation of the test by using a model based on the embedded cohesive crack developed by the authors in previous published works. Comparison of the results shows how the model is able to reproduce the size effect of the specimens in this material from the parameters that characterize fracture behaviour. The aim is to use the cohesive model proposed by the authors to move from laboratory tests to a built panel.
Construction and Application of Internal Medicine Teaching Interactive Course Based on 5-Star Instructional Model
Authors: Fang Qiong
Published: February 2019

With the continuously deepening education reform, to realize effective teaching as much as possible, teaching quality improvement becomes the precondition of building a moderately prosperous society. At the same time, teaching informationization also requires teachers to pay attention to keeping abreast of the times, adopt multimedia means for teaching and improve teaching efficiency. As new teaching concepts and teaching methods are required in the new era, five-star teaching theory focusing on problem-solving and the consistency of the teaching process and the learning process provides theoretical guidance for curriculum design through four steps, activating original knowledge, displaying and demonstrating new knowledge, trying application exercise, and integrated mastery. The classroom teaching interactive response system (CIRS) which attaches great importance to the interactive feedback between teachers and students, strengthens students' participation in the classroom can have a real-time control of teaching progress and adjust the teaching content in real time. Combination of five-star teaching theory and CIRS has the optimum effect on improving effective teaching. With internal medicine teaching course as the example, the study conducted smartphone CIRS course teaching model based on 5-Star Instructional Model, carried out experiments, and evaluated the experiment results through questionnaire survey. Experiment results show that the teaching mode received students’ full recognition, improved students' internal medicine teaching course scores and achieved good teaching results.
A “Maker Education + SPOC” Teaching Model for College Political Economics Courses
Authors: Fu Yunling
Published: February 2019

Analysis of the advantages of using the “maker education + SPOC” teaching model in college political economics courses from the perspective of maker education and SPOC reveals that this model can improve the teaching quality of political economics courses and cultivate students’ innovation ability and problem solving skills. Based on the offline teaching system, the model of applying “maker education + SPOC” in college political economics courses was designed from the aspects of teaching environment, teaching process and teaching evaluation, and Shandong Normal College in Shandong Province was took as a case to carry out a study on the teaching practice and teaching effect of the model. It was found that the model can positively influence the teaching effect of college political economics courses, and opinions and suggestions were put forward on the practice of the model.
Illustration Design Teaching Mode Based on Virtual Wall Painting Technology
Authors: Zhang Lingling
Published: February 2019

With rapid development of 3D virtual scene, virtual reality (VR) technology starts to be applied in teaching practice. Because of its conception and innovation, VR technology has certain advantage in art creation learning and teaching. In traditional art course teaching, theoretical knowledge is more than design practice, and the depth of design cases is insufficient. Thus, students lack driving force of art creation. On this basis, wall painting technology and VR technology were combined and applied in the course of Illustration Design in this paper. According to the course requirement of Illustration Design – many design cases, Illustration Design teaching mode based on virtual wall painting technology was constructed. The study result showed that, students more approved the new teaching mode, their interest improved greatly and teaching efficiency boosted significantly. The teaching mode can make up for defects of traditional art design teaching mode and contributes to cultivating students’ art creation ability.
A Learning Process Model to Enhance Digital Literacy using Critical Inquiry through Digital Storytelling (CIDST)
Authors: Kaeophanuek Siriwatchana , Na-Songkhla Jaitip , Nilsook Prachyanun
Published: February 2019

Digital literacy is important because it is the underpinning influence that sustains an individual’s competent and purposeful use of digital technology in education. Having digital literacy requires more than just the technical ability to operate digital devices properly; it also comprises a variety of skills that are utilized in executing tasks in digital environments, such as information skills, socio-emotional skills, cognitive skills and reproduction skills that the learner needs to master in order to use digital environments effectively. This research aim is to propose a learning process model to enhance digital literacy using critical inquiry through digital storytelling (CIDST). The research methodology was divided into two phases: the first phase involves document analysis and synthesis to develop the learning process model and the second phase involves evaluating the suitable learning model by experts. From the results, we anticipate that our learning process model could be used for reference on the part of teachers planning and implementing instructional activities to enhance the digital literacy of undergraduate students.
Student Experiences of Using Online Material to Support Success in A-Level Economics
Authors: McGuinness Natalie , Vlachopoulos Dimitrios
Published: February 2019

Current research has demonstrated that the leap from GCSEs to A-Levels is the greatest transition learners will go through in their educational journey. This paper looks into student attitudes towards utilising online resources to succeed in A-Level exams. Students are now expected to retain information across the two-year course, so this research looks into how educators can support such learning. Data tracking, questionnaires and interviews were conducted with Year One Economics students in a 16-19 educational institution in South-East England. The research identified that students require online resources to support them in their knowledge construction and retention; however, educators need to be wary of making certain assumptions. Learners’ digital capabilities are still developing, so educators need to promote online resources that will support learner needs, as well as ensure that the material is both accessible and easy to use
Augmented Reality Based Educational Design for Children
Authors: Sun Minghui , Wu Xinyu , Fan Zhihua , Dong Liyan
Published: February 2019

Human-computer interaction (HCI) has developed rapidly in recent years, and more and more researchers are interested in applying HCI techniques into education. Compared with traditional approaches in the real world, gesture recognition is considered as a reasonable alternative since it is vivid and flexible. However, most of educational equipment nowadays achieves the function of augmented reality, without any interaction. This paper implemented a prototype, not only based on augmented reality system, but also especially we think about the interactive design. Accessibility is achieved by mobile devices and the dynamic switch of gesture recognition. By this interactive method, children are able to interact with the virtual objects easily and naturally. Consequently, children can have a profound and deep understanding of what they learn, and the quality of education will be improved.
Analysis of Spectrum Selection Methods Based on Platform-Qualnet in Cognitive Radio Networks
Authors: Sun Hui , Han Han
Published: February 2019

Dynamic spectrum Access ï¼ˆDSAï¼‰is used to make use of the spectrum in wireless network. In most situations, control channel is a common approach to negotiation between secondary users. But, based on this feature, the attacker can destroy the communication network only influence the control center. So, in this paper, two methods without control channel are simulated in Qualent platform. The results prove that those methods are available, and the Receiver-directed channel selection is more match to the regular control channel standards in throughput.
Automatic Classification for Fruits’ Types and Identification of Rotten Ones Using k-NN and SVM
Authors: Nosseir Ann , Ahmed Seif Eldin  A.
Published: February 2019

Having a system that classifies different types of fruits and identifies the quality of fruits will be of a value in various areas especially in an area of mass production of fruits’ products. This paper presents a novel system that differentiates between four fruits types and identifies the decayed ones from the fresh. The algorithms used are based on the colour and the texture features of the fruits’ images. The algorithms extract the RGB values and the first statistical order and second statistical of the Gray Level Co-occurrence Matrix (GLCM) values. To segregate between the fruits’ types, Fine, Medium, Coarse, Cosine, Cubic, and Weighted K-Nearest Neighbors algorithms are applied. The accuracy percentages of each are 96.3%, 93.8%, 25%, 83.8%, 90%, and 95% respectively.  These steps are tested with 46 pictures taken from a mobile phone of seasonal fruits at the time i.e., banana, apple, and strawberry. All types were accurately identifying.  To tell apart the decayed fruits from the fresh, the linear and quadratic Support Vector Machine (SVM) algorithms differentiated between them based on the colour segmentation and the texture feature algorithms values of each fruit image. The accuracy of the linear SVM is 96% and quadratic SVM 98%.
Applying QCA with Fuzzy Logic to Generate a Refined set of Factors for Information Systems Adoption: The Case of Public Ecuadorian Organization, an Example of IS Adoption in Emerging Economies
Authors: Alcivar Nayeth I. , Sanzogni Louis , Houghton Luke
Published: February 2019

Information Systems (IS) research continues to contribute to a long list of technology adoption factors from many studies conducted outside the Latin American (LAT) nations. These investigations fail to appropriate the context of IS adoption in LAT. This fail is mainly due to the geographical scope of existing studies. Those aimed at North America for example, are out of context regarding a diverse technological approach when applied to LAT. Further, uncertainty and an inability to predict outcomes of technology adoption, create variances in results because the local contexts are not considered. The reasons for this are unclear from existing studies. To detailed explore this problem further, a Qualitative Comparative Analysis (QCA) was applied to LAT economies, expecting to assess a refined set of drivers from existing technology adoption studies. A Fuzzy Logic process was used to refine these drivers. The research found that fourteen themes are candidates for future study purposes. The drivers provide LAT stakeholders, as well as actors from other emerging economies, with a contextual frame that can be the basis for adopting technology more meaningfully within these nations
CyberMaster: An Expert System to Guide the Development of Cybersecurity Curricula
Authors: Hodhod Rania , Khan Shamim , Wang Shuangbao
Published: February 2019

The growing number of reported cyber-attacks pose a difficult challenge to individuals, governments and organizations. Adequate protection of information systems urgently requires a cybersecurity-educated workforce trained using a curriculum that covers the essential skills required for different cybersecurity work roles.  The goal of the CyberMaster expert system is to assist inexperienced instructors with cybersecurity course design. It is an intelligent system that uses visual feedback to guide the user through the design process. Initial test executions show the promise of such a system in addressing the enormous shortage of cybersecurity experts currently available for designing courses and training programs.
Buñuel o el exterminador de sus hijos cinematográficosReflexiones preliminares
Authors: Amiot-Guillouet Julie
Published: February 2019

Cine de adultos, el de Buñuel pocas veces se ha acercado al tema de la niñez. Desde este punto de vista – entre otros muchos – la película Los olvidados aparece excepcional en el panorama buñueliano. Lo que quisiera plantear aquí es cómo esta película destroza de manera sistemática a sus personajes infantiles, arraigándose no tanto en el antecedente muchas veces señalado que es Las Hurdes, sino más bien en la secuencia del infanticidio de La edad de oro. Si el discurso manifiesto de la película designa como responsables de la tragedia de los jóvenes a la sociedad y a sus injusticias, se puede observar que su muerte es al fin y al cabo un producto de la hybris de los adultos, y de la suya propia. Desde esta perspectiva, Buñuel evidencia el poder de los impulsos de sus personajes, en una representación incómoda, poco acorde con los requisitos de los buenos sentimientos, ya sean los de la sociedad, ya sean los de su reflejo cinematográfico, en el que logra atrapar al espectador para hacerlo cómplice de la matanza.
Evaluating solar radiation forecast uncertainty
Authors: Tuononen Minttu , O'Connor Ewan J. , Sinclair Victoria A.
Published: February 2019

Abstract. The presence of clouds and their characteristics have a strong impact on the
radiative balance of the Earth and on the amount of solar radiation reaching
the Earth's surface. Many applications require accurate forecasts of surface
radiation on weather timescales, for example solar energy and UV radiation
forecasts. Here we investigate how operational forecasts of low and mid-level
clouds affect the accuracy of solar radiation forecasts. A total of 4 years
of cloud and solar radiation observations from one site in Helsinki, Finland,
are analysed. Cloud observations are obtained from a ceilometer and therefore
we first develop algorithms to reliably detect cloud base, precipitation, and
fog. These new algorithms are widely applicable for both operational use and
research, such as in-cloud icing detection for the wind energy industry and
for aviation. The cloud and radiation observations are compared to forecasts
from the Integrated Forecast System (IFS) run operationally and developed by
the European Centre for Medium-Range Weather Forecasts (ECMWF). We develop
methods to evaluate the skill of the cloud and radiation forecasts. These
methods can potentially be extended to hundreds of sites globally. Over Helsinki, the measured global horizontal irradiance (GHI) is strongly
influenced by its northerly location and the annual variation in cloudiness.
Solar radiation forecast error is therefore larger in summer than in winter,
but the relative error in the solar radiation forecast is more or less
constant throughout the year. The mean overall bias in the GHI forecast is
positive (8 W m−2). The observed and forecast distributions in
cloud cover, at the spatial scales we are considering, are strongly skewed
towards clear-sky and overcast situations. Cloud cover forecasts show more
skill in winter when the cloud cover is predominantly overcast; in summer
there are more clear-sky and broken cloud situations. A negative bias was
found in forecast GHI for correctly forecast clear-sky cases and a positive
bias in correctly forecast overcast cases. Temporal averaging improved the
cloud cover forecast and hence decreased the solar radiation forecast error.
The positive bias seen in overcast situations occurs when the model cloud has
low values of liquid water path (LWP). We attribute this bias to the model
having LWP values that are too low or the model optical properties for
clouds with low LWP being incorrect.
Towards a more complete quantification of the global carbon cycle
Authors: Kirschbaum Miko U. F. , Zeng Guang , Ximenes Fabiano , Giltrap Donna L. , Zeldis John R.
Published: February 2019

Abstract. The main
components of global carbon budget calculations are the emissions from
burning fossil fuels, cement production, and net land-use change, partly
balanced by ocean CO2 uptake and CO2 increase in the
atmosphere. The difference between these terms is referred to as the residual
sink, assumed to correspond to increasing carbon storage in the terrestrial
biosphere through physiological plant responses to changing conditions
(ΔBphys). It is often used to constrain carbon
exchange in global earth-system models. More broadly, it guides expectations
of autonomous changes in global carbon stocks in response to climatic
changes, including increasing CO2, that may add to, or subtract
from, anthropogenic CO2 emissions. However, a budget with only these terms omits some important additional fluxes that are
needed to correctly infer ΔBphys. They are cement carbonation and
fluxes into increasing pools of plastic, bitumen, harvested-wood products, and landfill
deposition after disposal of these products, and carbon fluxes to the oceans via wind
erosion and non-CO2 fluxes of the intermediate breakdown products of methane
and other volatile organic compounds. While the global budget includes river transport of
dissolved inorganic carbon, it omits river transport of dissolved and particulate organic
carbon, and the deposition of carbon in inland water bodies. Each one of these terms is relatively small, but together they can constitute important
additional fluxes that would significantly reduce the size of the inferred ΔBphys. We estimate here that inclusion of these fluxes would reduce ΔBphys from the currently reported 3.6 GtC yr−1 down to about 2.1 GtC yr−1
(excluding losses from land-use change). The implicit reduction in the size of
ΔBphys has important implications for the inferred magnitude of
current-day biospheric net carbon uptake and the consequent potential of future
biospheric feedbacks to amplify or negate net anthropogenic CO2 emissions.
Regulation of N2O emissions from acid organic soil drained for agriculture: Effects of land use and season
Authors: Taghizadeh-Toosi Arezoo , Elsgaard Lars , Clough Tim J. , Labouriau Rodrigo , Ernstsen Vibeke , Petersen Søren O.
Published: February 2019

Abstract. Drained organic soils are extensively used for cereal and high-value cash crop production or as grazing land, but emissions of nitrous oxide (N2O) are enhanced by the drainage and cultivation. A study was conducted to investigate the regulation of N2O emissions in a raised bog area drained for agriculture. The area has been classified as potentially acid sulfate soil, and we hypothesised that pyrite oxidation was a potential driver of N2O emissions. Two sites with rotational grass, and two sites with a potato crop, were equipped for monitoring of N2O emissions, as well as sub-soil N2O concentrations at 5, 10, 20, 50 and 100 cm depth, during spring and autumn 2015. Precipitation, air and soil temperature, soil moisture, water table (WT) depth, and soil mineral N were recorded during weekly field campaigns. In late April and early September, intact cores were collected to 1 m depth at adjacent grassland and potato sites for analysis of soil properties, which included acid volatile sulfide (AVS) and chromium-reducible sulfur (CRS) to quantify, respectively, iron monosulfide (FeS) and pyrite (FeS2), as well as total reactive iron (TRFe) and nitrite (NO2−). Soil organic matter composition and total reduction capacity was also determined. The soil pH varied between 4.7 and 5.4. Equivalent soil gas phase concentrations of N2O ranged from around 10 µL L−1 at grassland sites to several hundred µL L−1 at potato sites, in accordance with lower soil mineral N concentrations at grassland sites. Total N2O emissions during 152–174 days were 3–6 kg N2O-N ha−1 for rotational grass, and 19–21 kg N2O-N ha−1 for potato sites. Statistical analyses by graphical models showed that soil N2O concentration in the capillary fringe was the strongest predictor for N2O emissions in spring, and for grassland sites also in the autumn. For potato sites in the autumn, nitrate (NO3−) availability in the top soil, together with temperature, were the main controls on N2O emissions. Pyrite oxidation coupled with NO3− reduction could not be dismissed as a source of N2O, but the total reduction capacity of the peat soil was much higher than explained by the FeS2 concentration. The concentrations of TRFe were also much higher than pyrite concentrations, and potentially chemodenitrification could have been a source of N2O during WT drawdown in spring. The N2O emissions associated with rapid soil wetting and WT rise in autumn were consistent with biological denitrification. Soil N availability and seasonal WT changes were important controls of N2O emissions.
A dataset of 30-meter annual vegetation phenology indicators (1985–2015) in urban areas of the conterminous United States
Authors: Li Xuecao , Zhou Yuyu , Meng Lin , Asrar Ghassem R. , Lu Chaoqun , Wu Qiusheng
Published: February 2019

Abstract. Fine-resolution satellite observations show great potential for characterizing seasonal and annual dynamics of vegetation phenology in urban domains, from local to regional and global scales. However, most previous studies were conducted using coarse or moderate resolution data, which are inadequate for characterizing the spatiotemporal dynamics of vegetation phenology in urban domains. In this study, we produced an annual vegetation phenology dataset in urban ecosystems for the conterminous United States (US), using all available Landsat images on the Google Earth Engine (GEE) platform. First, we characterized the long-term mean seasonal pattern of phenology indicators of the start of season (SOS) and the end of season (EOS), using a double logistic model. Then, we identified the annual variability of these two phenology indicators by measuring the difference of dates when the vegetation index in a specific year reaches the same magnitude as its long-term mean. The derived phenology indicators agree well with in-situ observations from PhenoCam network and Harvard Forest. Comparing with results derived from the moderate resolution imaging spectroradiometer (MODIS) data, our Landsat derived phenology indicators can provide more spatial details. Also, temporal trends of phenology indicators (e.g., SOS) derived from Landsat and MODIS are consistent overall, but the Landsat derived results from 1985 have a longer temporal span compared to MODIS from 2001. In general, there is a spatially explicit pattern of phenology indicators from the North to the South in cities in the conterminous US, with an overall advanced SOS in the past three decades. The derived phenology product in the US urban domains at the national level is of great use for urban ecology studies for its fine spatial resolution (30 m) and long temporal span (30 years). The data are available at https://doi.org/10.6084/m9.figshare.7685645.v2.
In Love and Trouble: Stories of Black Women
Authors: Rosenfelt Deborah
Published: February 2019

This collection of stories works well to introduce literature students to issues of race, gender, and class.
Critical Teaching and Everyday Life
Authors: Alexander Buzz
Published: February 2019

This Teaching Note describes Ira Shor’s work developing Freirian pedagogy for the college classroom and the use of his book in a graduate course for teachers.
Kiss of the Spider Woman
Authors: Kampf Louis
Published: February 2019

An Argentinian novel about two cell mates -- one imprisoned for being gay, the other for his Marxist politics – “convincingly ties the political to the sexual” for students in a women’s studies course.
Reconciling Native Son and Native Daughters
Authors: Estes-Hicks Onita
Published: February 2019

Richard Wright’s novel meets serious resistance from students but sudden and intense media attention on a police manhunt for a young black man brings them a new perspective on the book.
Reading the Romance: Women, Patriarchy, and Popular Literature
Authors: Ohmann Richard
Published: February 2019

In a class on popular fiction, this book leads students to a more sophisticated understanding of what Harlequin romances and similar books might mean to their readers.
Ethnic Notions
Authors: Radner Susan
Published: February 2019

This documentary film traces the historical changes in racist imagery of African Americans and helps students understand the role representation plays in justifying and sustaining oppression.
Raising Awareness of Social Justice and War Through Film and Poetry
Authors: Gaylie Veronica
Published: February 2019

Student middle-school teachers view the documentary Voices in Wartime and are moved to dedicate a “Peace Tree” on their campus.
Can Critical Teaching Foster Activism in this Time of Repression?
Authors: Shor Ira
Published: February 2019

This Teaching Note provides a brief description of “participatory approaches with subject matters that are local, contemporary, contentious, co-developed, and legible” in a required composition course.
Introduction
Authors: Rosen Bob
Published: February 2019

This is the introduction to the cluster of 47 Teaching Notes, reprinted from past issues of Radical Teacher.
The Case Against Education by Bryan Caplan
Authors: Davis James
Published: February 2019

Review of Bryan Caplan, The Case Against Education: Why the Education System is a Waste of Time and Money (Princeton University Press, 2018)
ANÁLISE ESPAÇO-TEMPORAL DAS CHUVAS PERSISTENTES NA REGIÃO DO PARQUE ESTADUAL DO RIO DOCE–PERD, SOB INFLUÊNCIAS DAS ZCAS E ZCOU (OUT/2015 A DEZ/2016)
Authors: Lima Jean Monteiro , Cupolillo Fulvio
Published: February 2019

Este artigo tem por objetivo analisar os eventos de chuvas persistentes que ocorreram na região do Parque Estadual do Rio Doce (PERD), para o período de outubro de 2015 a dezembro de 2016, por meio de elaboração de mapas decendiais de precipitações, com dados fornecidos das estações  meteorológicas automáticas de Timóteo e Caratinga fornecidos pelo INMET e com o uso software ArcGIS 10.5. Assim, foi analisado o decêndio de cada mês, observando os maiores e menores índices totais pluviométricos bem como os eventos: Zona de Convergência da América do Sul (ZCAS) e Zona de Convergência de Umidade (ZCOU), que geraram as chuvas persistentes na região. Os resultados evidenciaram a estreita relação entre os eventos de ZCAS e ZCOU e catástrofes urbanas como enchentes e deslizamentos, ocorridos nos município do entorno do PERD, bem como demonstram a urgente e crescente necessidade do planejamento estratégico por parte do poder público e da população na organização do espaço geográfico de modo a evitar transtornos como a perda de vidas humanas, prejuízos materiais e danos ambientais, devido à influência destes mecanismos atmosféricos na gênese das chuvas persistentes e seus efeitos no Bioma Mata Atlântica e sistemas lacustres doPERD.
DINÂMICA CLIMÁTICA REGIONAL EM MUNICÍPIOS DA ZONA DA MATA, CAMPO DAS VERTENTES E SUL E SUDOESTE DE MINAS GERAIS: AS ONDAS DE CALOR E FRIO
Authors: De Oliveira Daiane Evangelista , De Assis Débora Couto , Ferreira Cássia De Castro Martins
Published: February 2019

O presente estudo teve por objetivo estudar, identificar e caracterizar, nas séries históricas de 1993 a 2011, os episódios de Ondas de calor e frio. Para isso, foi feito um recorte geográfico delimitando o objeto de estudo em áreas localizadas nos municípios da Zona da Mata (Juiz de Fora e Viçosa), Campo das Vertentes (Barbacena e Lavras), Sul e Sudoeste de Minas Gerais (Machado, Caldas e São Lourenço), buscando assim reconhecer os padrões espaço-temporais com que se manifestaram na área. Os dados utilizados foram de temperatura do ar máxima diária (Tmax) e mínima diária (Tmin), obtidas através do banco de dados do INMET. Os eventos de ondas foram identificados e contabilizados a partir de duas técnicas, sendo uma delas o período em que durante cinco ou mais dias registrou-se Tmax e Tmin superando a médias mais um desvio padrão; e a outra de dias consecutivos de temperatura superiores ou inferiores a 5°C em relação à média do período. Por fim, os dados foram espacializados com a finalidade de verificar a sua distribuição espacial, além de sua correlação com outras variáveis físicas. Os resultados indicaram que os municípios localizados à Oeste apresentaram um maior quantitativo de ondas de calor, enquanto que os à Leste apresentaram um maior quantitativo de ondas de Frio. Concluindo-se então que o relevo é o principal fator geográfico para a variabilidade dos regimes térmicos.
CLIMATOLOGIA DA PROFUNDIDADE ÓTICA E DEPENDÊNCIA ESPECTRAL DE AEROSSÓIS EM REGIÕES DE FLORESTA E CERRADO NO BRASIL
Authors: Menezes Jorge Almeida , Palácios Rafael Da Silva , De Menezes Evanízio Marinho , Nogueira José De Souza
Published: February 2019

Aerossóis atmosféricos desempenham um papel importante no equilíbrio de energia do sistema Terra-atmosfera. Medidas de aerossóis foram realizadas em quatro sítios, dois em área de floresta (Rio Branco e Ji-Paraná) e dois em área de Cerrado (Cuiabá e Campo Grande), utilizando fotômetro solar da rede global AERONET. Dados de 5 anos permitiram classificar as propriedades óticas dos aerossóis, definindo a climatologia para cada sítio. Neste trabalho a profundidade óptica de aerossol (AOD 440nm) e expoente Angstrom, α(440-870), foram utilizados para a análise espectral de aerossol. Médias de AOD(440nm) para sítios de Cerrado foram, respectivamente, 0,29 (±0,40), 0,18(±0,24), com média correspondente de α 1,20(±0,39), 1,16(±0,36). Médias de AOD(440nm) para sítios de Floresta são, respectivamente, 0,85(±0,71), 0,35(±0,44), com média correspondente de α  1,38(±0,41), 1,40(±0,34). A AOD(440nm) tanto para regiões de Cerrado como de Floresta mostram picos distintos para estação seca e chuvosa, sendo que estão relacionados com padrões sazonais de aerossóis característicos dessas regiões. O α (440-870) apresentou modos de frequência que relacionam-se com os principais tipos de aerossóis presentes tanto em Cerrado como em Floresta. Um cenário principal de aerossóis foi definido como aerossóis oriundos de queima de biomassa, com forte influência de fontes locais de aerossóis poluídos. Mistura de aerossóis estão presentes, enquanto que poeira em suspensão tem uma ocorrência pouco relevante.
O ESTUDO DAS TENDÊNCIAS PLUVIOMÉTRICAS NO MUNICÍPIO DE IRATI/PR
Authors: Pinheiro Gabriela Marques , Vide Javier Martin
Published: February 2019

As mudanças climáticas globais, suas causas e consequências têm ganhado cada vez mais importância no cenário mundial. De acordo com o Primeiro Relatório de Avaliação Nacional (RAN-1), do Painel Brasileiro de Mudanças Climáticas, a projeção para mudanças da precipitação para a região Sul da América do Sul prevê, até 2040, aumento de 5% a 10%. Neste contexto, esta trabalho tem por objetivo principal compreender a variabilidade pluviométrica (1980 a 2010), assim como analisar tendências futuras para eventos pluviais no município de Irati, localizado na região sudeste do estado do Paraná. Dessa forma, foram utilizadas técnicas estatísticas para cálculo da variabilidade e tendências pluviométricas. Os resultados demostraram que a cidade não apresenta tendências positiva e negativa de precipitação para as últimas 30 décadas. Dessa forma, os dados corroboram para o melhor entendimento da gênese das chuvas bem como para os estudos sobre os impactos regionais e locais das mudanças climáticas e variabilidade climática.