bluuebunny/crossref_metadata_2025 huggingface dataset:
Breaking Resonant Chains: Destabilization of Resonant Planets Due to Long-term Mass Evolution
Authors: Matsumoto Yuji , Ogihara Masahiro
Published: April 2020

Recent exoplanet observations reported a large number of multiple-planet systems, in which some of the planets are in a chain of resonances. The fraction of resonant systems to non-resonant systems provides clues about their formation history. We investigated the orbital stability of planets in resonant chains by considering the long-term evolution of planetary mass and stellar mass and using orbital calculations. We found that while resonant chains were stable, they can be destabilized by a change of ∼10% in planetary mass. Such a mass evolution can occur by atmospheric escape due to photoevaporation. We also found that resonant chains can be broken by a stellar mass loss of ≲1%, which would be explained by stellar winds or coronal mass ejections. The long-term mass change of planets and stars plays an important role in the orbital evolutions of planetary systems, including super-Earths.
Evidence for Disk Truncation at Low Accretion States of the Black Hole Binary MAXI J1820+070 Observed by NuSTAR and XMM-Newton
Authors: Xu Yanjun , Harrison Fiona A. , Tomsick John A. , Hare Jeremy , Fabian Andrew C. , Walton Dominic J.
Published: April 2020

We present results from NuSTAR and XMM-Newton observations of the new black hole X-ray binary MAXI J1820+070 at low accretion rates (below 1% of the Eddington luminosity). We detect a narrow Fe Kα emission line, in contrast to the broad and asymmetric Fe Kα line profiles commonly present in black hole binaries at high accretion rates. The narrow line, with weak relativistic broadening, indicates that the Fe Kα line is produced at a large disk radius. Fitting with disk reflection models assuming standard disk emissivity finds a large disk truncation radius (a few tens to a few hundreds of gravitational radii, depending on the disk inclination). In addition, we detect a quasi-periodic oscillation (QPO) varying in frequency between 11.6 ± 0.2 mHz and 2.8 ± 0.1 mHz. The very low QPO frequencies suggest a large size for the optically thin Comptonization region according to the Lense–Thirring precession model, supporting that the accretion disk recedes from the innermost stable circular orbit and is replaced by advection-dominated accretion flow at low accretion rates. We also discuss the possibility of an alternative accretion geometry that the narrow Fe Kα line is produced by a lamppost corona with a large height illuminating the disk.
The Composite X-Ray Spectrum of 3CRR Quasars
Authors: Zhou Minhua , Gu Minfeng
Published: April 2020

The reason for the difference between the composite X-ray spectrum for radio-loud quasars (RLQs) versus radio-quiet quasars (RQQs) is still unclear. To study this difference, we built a new composite X-ray spectrum of RLQs using Chandra X-ray data and Sloan Digital Sky Survey optical data for the sample of 3CRR quasars. We find the X-ray spectra of all 3CRR quasars, except for 3C 351, have no soft X-ray excess and can be fitted well with an absorbed power-law model. Our composite X-ray spectrum is similar to that of Shang et al. for RLQs, showing higher hard X-ray and lower soft X-ray flux than the composite X-ray spectrum of RQQs. Most blazar-like 3CRR quasars have higher X-ray flux than the median composite X-ray spectrum, which could be related to the contribution of beamed jet emission at X-ray band. From the literature, we find that nineteen 3CRR quasars have extended X-ray emission related to radio jets, indicating the inevitable contribution of jets at X-ray band. In contrast to RQQs, the X-ray photon index of 3CRR quasars does not correlate with the Eddington ratio. Our results suggest that the jet emission at X-ray band in RLQs could be related to the difference in composite X-ray spectrum between RLQs and RQQs.
ALMA Polarimetry Measures Magnetically Aligned Dust Grains in the Torus of NGC 1068
Authors: Lopez-Rodriguez Enrique , Alonso-Herrero Almudena , García-Burillo Santiago , Gordon Michael S. , Ichikawa Kohei , Imanishi Masatoshi , Kameno Seiji , Levenson Nancy A. , Nikutta Robert , Packham Chris
Published: April 2020

The obscuring structure surrounding active galactic nuclei (AGN) can be explained as a dust and gas flow cycle that fundamentally connects the AGN with their host galaxies. This structure is believed to be associated with dusty winds driven by radiation pressure. However, the role of magnetic fields, which are invoked in almost all models for accretion onto a supermassive black hole and outflows, has not been thoroughly studied. Here we report the first detection of polarized thermal emission by means of magnetically aligned dust grains in the dusty torus of NGC 1068 using ALMA Cycle 4 polarimetric dust continuum observations (0.″07, 4.2 pc; 348.5 GHz, 860 μm). The polarized torus has an asymmetric variation across the equatorial axis with a peak polarization of 3.7% ± 0.5% and position angle of 109° ± 2° (B-vector) at ∼8 pc east from the core. We compute synthetic polarimetric observations of magnetically aligned dust grains assuming a toroidal magnetic field and homogeneous grain alignment. We conclude that the measured 860 μm continuum polarization arises from magnetically aligned dust grains in an optically thin region of the torus. The asymmetric polarization across the equatorial axis of the torus arises from (1) an inhomogeneous optical depth and (2) a variation of the velocity dispersion, i.e., a variation of the magnetic field turbulence at subparsec scales, from the eastern to the western region of the torus. These observations and modeling constrain the torus properties beyond spectral energy distribution results. This study strongly supports that magnetic fields up to a few parsecs contribute to the accretion flow onto the active nuclei.
Retrograde-rotating Exoplanets Experience Obliquity Excitations in an Eccentricity-enabled Resonance
Authors: Kreyche Steven M. , Barnes Jason W. , Quarles Billy L. , Lissauer Jack J. , Chambers John E. , Hedman Matthew M.
Published: April 2020

Previous studies have shown that planets that rotate retrograde (backward with respect to their orbital motion) generally experience less severe obliquity variations than those that rotate prograde (the same direction as their orbital motion). Here, we examine retrograde-rotating planets on eccentric orbits and find a previously unknown secular spin–orbit resonance that can drive significant obliquity variations. This resonance occurs when the frequency of the planet’s rotation axis precession becomes commensurate with an orbital eigenfrequency of the planetary system. The planet’s eccentricity enables a participating orbital frequency through an interaction in which the apsidal precession of the planet’s orbit causes a cyclic nutation of the planet’s orbital angular momentum vector. The resulting orbital frequency follows the relationship

, where

and

are the rates of the planet’s changing longitude of periapsis and longitude of ascending node, respectively. We test this mechanism by simulating cases of a simple Earth–Jupiter system and confirm the predicted resonance. Over the course of 100 Myr, the test Earths with rotation axis precession rates near the predicted resonant frequency experienced pronounced obliquity variations of the order of 10°–30°. These variations can be significant and suggest that while retrograde rotation is a stabilizing influence most of the time, retrograde rotators can experience large obliquity variations if they are on eccentric orbits and enter this spin–orbit resonance.
Vernal pool amphibian breeding ecology monitoring from 1931 to present: A harmonised historical and ongoing observational ecology dataset
Authors: Garretson Alexis , Napoli Megan , Feldsine Natalie , Adler-Colvin Penelope , Long Elizabeth
Published: April 2020

For 88 years (1931-present), the Mohonk Preserve's Daniel Smiley Research Center has been collecting data on occupancy and reproductive success of amphibian species, as well as associated water quality of 11 vernal pools each spring (February to May). Though sampling effort has varied over the dataset range, the size of the dataset is unprecedented within the field of amphibian ecology. With more than 2,480 individual species sampling dates and more than 151,701 recorded individual occurrences of the nine amphibian species, the described dataset represents the longest and largest time-series of herpetological sampling with paired water quality data.

We describe the novel publication of a paired dataset of amphibian occurrence with environmental indicators spanning nearly 90 years of data collection. As of February 2020, the dataset includes 2,480 sampling dates across eleven vernal pools and 151,701 unique occurrences of egg masses or individuals recorded across nine species of amphibian. The dataset also includes environmental conditions associated with the species occurrences with complete coverage for air temperature and precipitation records and partial coverage for a variety of other weather and water quality measures. Data collection has included species, egg mass and tadpole counts; weather conditions including precipitation, sky and wind codes; water quality measurements including water temperature and pH; and vernal pool assessment including depth and surface vegetation coverage. Collection of data was sporadic from 1931–1991, but data have been collected consistently from 1991 to present. We also began monitoring dissolved oxygen, nitrate concentrations and conductivity of the vernal pools using a YSI Sonde Professional Plus Instrument and turbidity using a turbidity tube in February 2018. The dataset (and periodic updates), as well as metadata in the EML format, are available in the Environmental Data Initiative Repository under package edi.398.
Nearctic walnut leafminers invade Europe: first Coptodisca lucifluella (Clemens, 1860) and now Coptodisca juglandiella (Chambers, 1874) (Lepidoptera, Heliozelidae)
Authors: Takács Attila , Szabóky Csaba , Tóth Balázs , Bozsó Miklós , Kutas János , Molnár Szilárd , Richter Ignác
Published: April 2020

The Nearctic leafminer of black walnut Coptodisca juglandiella (Chambers, 1874) was found in Hungary and reported as new for Europe. Larvae were found in leafmines on black walnut (Juglans nigra (L.)), white walnut (J. cinerea (L.)) and Arizona walnut (J. major (Torr.)); the latter two Juglans species are new host plant records for C. juglandiella. Mines of Coptodisca lucifluella (Clemens, 1860), another Nearctic invader, were found on leaves of bitternut hickory (Carya cordiformis (Wangenh.) K.Koch) and Caucasian wingnut (Pterocarya fraxinifolia (Lam). Spach.) (a new hostplant record), in addition to common walnut (Juglans regia L.). Interestingly, C. lucifluella is thought to have performed a host plant shift after its introduction into Europe, whereas C. juglandiella apparently did not. Coptodisca juglandiella has three generations in Hungary. The autumn generations of both species produced many more mines than the spring generations. One hymenopteran parasitoid specimen was reared from C. juglandiella. Larvae, mines and adults of C. juglandiella and C. juglandiella can be easily distinguished, differences are presented and illustrated. The genitalia of C. juglandiella are described for the first time.
Potential Effects of Antidepressant Agents: on the Growth & Development of Children & Adolescents
Authors: Nardi Deena A. , Barrett Sue
Published: April 2020

The regulatory bodies of both the United States and United Kingdom have issued cautionary statements about prescribing antidepressant medications to treat major depressive disorder (MDD) in children younger than age 18. Despite these cautions, antidepressant agents, particularly SSRIs and serotonin activators, are regularly used to treat MDD in this age group, and increasingly so in very young children. This article considers the possible effects of antidepressant agents on the growth and development of children younger than age 18 and provides recommendations for the use and careful monitoring of these medications, including screening for physiological effects, self-injurious behavior, and suicidal ideation. Guidelines for use of antidepressant agents with these populations include incorporating medications into comprehensive, holistic treatment, assessing for onset of severe akathesia as a marker of increased risk for self-harm, and advocating for more clinical trials of these medications in different childhood age groupings.
Mindfulness and Job Satisfaction Among Hospital Nurses: The Mediating Roles of Positive Affect and Resilience
Authors: Lin Lin , Liu Xingling , He Guoping
Published: April 2020

The current study aimed to explore the relationships between nurses' mindfulness and job satisfaction and the mediating roles of positive affect and resilience. A total of 1,043 Chinese hospital nurses completed self-report questionnaires from March to April 2019. Pearson's correlation analysis was used to identify the relationships among the four variables, and the bias-corrected bootstrap method was used to test the mediation hypotheses. The results revealed that nurses' mindfulness was at a medium-high level, whereas positive affect, resilience, and job satisfaction were at medium levels. The total scores and dimension scores of the four variables showed strong positive correlations, and nurses' mindfulness affected job satisfaction directly and indirectly through the intermediary roles of positive affect and resilience. Nursing managers should recognize the importance of mindfulness and incorporate mindfulness training into health promotion and employee management plans for hospital nurses. In addition, strategies should be implemented to cultivate positive affect and resilience. [
Journal of Psychosocial Nursing and Mental Health Services, 58
(6), 46–55.]
Model of Empathic Pain Assessment and Treatment in Persons With Dementia
Authors: Starr Lauren T. , Magan Kristin Corey
Published: April 2020

The current article presents an evidence-based model for understanding clinical empathy's relationship with the assessment and treatment of pain in persons with advanced dementia. A literature review informed creation of an interdisciplinary conceptual framework of clinician empathy in pain assessment and treatment among persons with advanced dementia. Driven by observation of behaviors indicating pain in persons with dementia unable to self-report, the model represents the cognitive, affective, ethical, and behavioral components of clinical empathy involved in assessing and treating pain, relevant patient outcomes, and contextual factors influencing empathy and outcomes; and provides a framework for testing clinical empathy interventions to improve adverse outcomes in persons with advanced dementia. Understanding the relationship between clinician empathy and the assessment and treatment of pain in persons with advanced dementia may improve care quality and help reduce pain behaviors in this patient population. This model may be used to inform pain research in persons with dementia and develop clinical interventions and clinician education programs. [Research in Gerontological Nursing, 13(5), 264–276.]
Coconut Fiber Reinforced Cement-Based Composites
Authors: Rabma Siriphorn , Narksitipan Suparut , Jaitanong Nittaya
Published: April 2020

The aim of this research was to study the properties of cement reinforced with coconut fiber. The coconut fiber addition that uses in this research were 5, 10 and 15% by weight of cement. The cement paste and coconut fiber were mixed together and packed into an iron mold. Then, the specimens were kept at room temperature for 24 hours and were moist cured in the water bath at 3, 7 and 28 days. After that, the physical properties i.e. water absorption and density were examined. The microstructure was characterized by scanning electron microscopy (SEM). The results showed the surfaces of the coconut fibers were not smooth, spread with nodes and irregular stripes, which is covered with substances and other impurities. The compressive strength and flexural strength were also investigated. From the results, the mechanical properties were decreased with increasing coconut fiber content due to reducing density and higher porosity and water absorption compared to non-fiber cement paste and physical properties of fiber had been flexibility and smoother caused poor binding with cement. The best compressive strength and flexural strength results were obtained with the percentages of coconut fiber as 5% which value as 26.67 N/mm2 and 5.08 N/mm2 respectively.
Characterization of Mesoporous Silica and its Application as an Adsorbent for Benzene Sensing
Authors: Chayasombat Bralee , Muensri Pitchaya , Klinthongchai Yoothapong , Inpor Kroekchai , Santawitee Onuma , Debeda Helene , Thanachayanont Chanchana , Prichanont Seeroong
Published: April 2020

Mesoporous silica (MPS) is a porous silica material with various pore structures. In this study, mesocellular foam silica (MCF) was synthesized and functionalized by hexamethyldisilazane (HMDS) to study effects of surface chemistry on benzene adsorption capability. Physical and chemical properties of pristine and functionalized MCFs were characterized and compared. Scanning and transmission electron microscopy showed that the complex pore structures of the MCFs were retained after the functionalization at relatively high temperature (573K). TGA and FTIR results showed that the functionalization led to a reduction of water adsorbed on the surfaces of the MCF. The functionalization improved adsorption of benzene compared to the pristine MCF and the optimum HMDS:SiO2 molar ratio was 1.5. The amount of benzene adsorbed has a linear relationship with the concentration of benzene in the environment. This relationship enables quantitative benzene detection by using the functionalized MCF as sensing materials in resistive-type or gravimetric-type benzene gas sensors.
Effect of Metal Precursor Solution on Morphology of Porous LaCoO3
Authors: Boonlha Sukit , Chakthranont Pongkarn , Kityakarn Sutasinee
Published: April 2020

Porous materials are attractive in various applications such as energy storage and production, industrial processing, environmental treatment, and catalysis. Porous LaCoO3 was prepared using three different metal precursor solutions: i) 40%v/v methanol-ethylene glycol (40%Me/EG), ii) Lysine (Lys), and iii) Lysine/citric acid (Lys/Cit) with poly(methyl methacrylate) colloidal crystal as porous templates (PMMA-CCT). PMMA-CCT filled with metal precursor solution were carbonized under N2 followed by oxidized under 50% O2 in N2 atmosphere. X-ray diffraction patterns of the obtained porous LaCoO3 are rhombohedral LaCoO3 phase without impurity. The scanning electron microscopy (SEM) was carried out to examine the morphology of porous LaCoO3. The SEM image of the LCO-Lys/Cit exhibits better connected particles and a well-defined pore structure compared to those prepared by Lys or 40%Me/EG metal precursor solutions. The evolution of pore formation of LCO-Lys/Cit was investigated by SEM, Fourier transform infrared spectroscopy (FT-IR), and thermal gravitational analysis (TGA). The materials show high catalytic properties for the electrochemical water oxidation reaction. The high capacitances of all porous LaCoO3 are attributed to the controlled three-dimensional porous morphology of the catalysts. This synthesis approach can achieve porous materials with promising properties for catalysis applications.
A Morphological Investigation of Ag/Graphite Oxide/TiO2 Composites for Photocatalysis
Authors: Junin Chabaiporn , Worayingyong Attera , Kongmark Chanapa , Yordsri Visittapong , Chayasombat Bralee , Thanachayanont Chanchana , Klysubun Wantana
Published: April 2020

To handle persistent toxic organic contaminants in water, advanced oxidation process (AOP) by titanium dioxide (TiO2) and its composites has been extensively utilized. A smart combination of composite materials was synthesized to improve photocatalytic activity of TiO2 via engineering effective charge transfer. In this study, synthesis of Ag/Graphite Oxide (GO)/TiO2 was investigated. Degussa P25 TiO2 (Rutile:Anatase of 85:15, 99.9%, 20nm) nanopowder was purchased. Graphite oxide was prepared using modified Hummer’s method. Photoreduction and ultrasonication were conducted to prepare Ag nanoparticles (AgNPs). XRD was used to confirm formation of Ag- GO- TiO2, i.e., peaks of GO, AgNPs and phases of anatase and rutile of TiO2 P25. Backscattered SEM was used to identify the AgNPs in different compositions of the AgNPs/GO/TiO2 composites. TEM was used for high resolution images to observe sizes and shapes of nanomaterials involved. X-ray absorption near edge structure (XANES) spectra of the Ag L3-edge were used to confirm zero-valence AgNPs. The best performed photocatalyst from this study was 5Ag0.5GOTiO2 with 78.86 % degradation of RhB after 2 hours. The AgNPs were found to be spherical with sizes of around 2-10 nanometers and evenly distributed within the GO/TiO2 matrix.
Feasibility Study of Using Modified Recycled Fiber-Cement for the Production of High Performance Fiber-Cement Composites
Authors: Pahusuwanno Peerapat , Chakartnarodom Parinya , Kongkajun Nuntaporn , Prakaypan Wichit
Published: April 2020

The aim of this work is to study the feasibility of recycling the rejected fiber-cement composites as the filler in the fiber-cement mixture for producing the new fiber-cement composites. The rejected fiber-cement composites were ground and mixed with ordinary Portland cement (OPC), sand, cellulose fiber, and the dissolving agent which was a chemical prepared from the proprietary blend of citric acid together with thickening and wetting agent. The samples (75 mm × 200 mm × 7 mm) were prepared by mixing the raw materials, including 34.25 wt% OPC, 30 wt% sand, 5.5 wt% cellulose fiber, and 30.25 wt% recycled fiber-cement composites. Then, the dissolving agent was added in the amount of 0 to 4.5 % of the OPC weight in the mixture. The mixtures of raw materials were mixed with water to form the slurry. Then, the green samples were produced by the filter pressing method. After molding, the green samples were autoclaved at pressure 10 bars and temperature 180 °C for 16 hrs. After that, the microstructure of the autoclaved samples was examined by scanning electron microscope (SEM). The modulus of rupture (MOR) and modulus of elasticity (MOE) of the samples were measured by universal testing machine (UTM) based on ASTM C1186-08 standard. The results showed that properties of the samples passed the requirements of the industrial standard. In addition, the utilization of dissolving agent affects both the microstructure and the properties of the samples.
PARAMETERS OF INTEREST FOR THE DESIGN OF GREEN INFRASTRUCTURE
Authors: Šperac Marija , Obradović Dino
Published: April 2020

The urbanization process significantly reduced the permeability of land surfaces, which affected the changes of runoff characteristics and the relations in the hydrological cycle. In urban environments, the relationships within the hydrological cycle have changed in quantity, in particular: precipitation, air temperature, evaporation, and infiltration. By applying the green infrastructure (GI) to urban environments is beneficial for the water resources and the social community. GI has an effect on the improvement of ecological, economic, and social conditions. Using GI into urban areas increases the permeability of land surfaces, whereby decreasing surface runoff, and thus the frequency of urban floods. It also has a significant influence on the regulation of air quality, water purification, climate change impact, and the changes in the appearance of the urban environment. When planning and designing the GI, it is necessary to identify the type of GI and determine the size and location of the selected GI. Since each urban environment has its own characteristics, it is necessary to analyze them before deciding on the GI. The paper analyzed meteorological parameters (precipitation, air temperature, insolation, air humidity) affecting the selection of GI types, using the specific example of an urban environment – the City of Osijek, Croatia. Significant parameters when designing GI are operation and maintenance These parameters directly affect the efficiency of GI. The proper selection of GI and its location results in maximum gains: the reduction of land surface drainage - drainage of the sewage system, purification and retention of precipitation at the place of production, the improvement of air quality, and the improvement of living conditions in urban environments
TIME OF CONCENTRATION IN AN EXPERIMENTAL BASIN: METHODS FOR ANALYSIS, BACKWATER EFFECTS AND VEGETATION REMOVAL
Authors: Malutta Simone , Pscheidt Jhonathan Cristian , Neto Tiago Guizoni , Klein Silvana , Bonumá Nádia Bernardi , Chaffe Pedro Luiz Borges , Kobiyama Masato
Published: April 2020

There are several empirical and theoretical formulas used for the estimation of the time of concentration (Tc). However, it has been shown that the Tc estimation may vary in several orders of magnitude depending on the method. In this study we compare 10 different methods for the estimation of the Tc using sub-basins and backwater effects to analyze those results. We also analyzed if the vegetation removal changes the Tc in the basin. The study area is the basin of the Federal University of Santa Catarina (UFSC) campus in Joinville with a significant part in a wetland and there is backwater effect caused by the Piraí river. Applying the empirical and theoretical equations found a significant variation of Tc estimates, the standard deviation in relation to the general average was around 65%. The influence of vegetation removal and drainage of a canal had an effect of reducing the Tc by 50%.
UTILIZATION OF MAXIMUM POWER IN AIRFOIL BLADE OF HORIZONTAL AXIS WIND TURBINE BY THE CONCEPT OF CFD ANALYSIS
Authors: Choubey Abhishek
Published: April 2020

Pollution free power production, quick installation and commissioning capability, less operation and maintenance cost and taking benefit of by means of free and renewable energies are all advantages of using wind turbines as an power generators. Along with these advantages, the main drawback of this source is the conditional nature of wind flow. Therefore, using reliable and efficient apparatus is necessary in order to get as much as energy from wind during the limited period of time that it flows strongly. Wind power is the fastest increasing renewable energy resource and wind power penetration in power systems increases at a significant rate. The high access of wind power into power systems in the present and near future will have several impacts on their planning and operation. A wind turbine transforms the kinetic energy in the wind to mechanical energy in a shaft and ultimately into electrical energy in a generator. Turbine blade is the mainly important part of any wind turbine. In this paper we consider single airfoil NACA 0018 and done CFD analysis at different blade angles 00,100,150 and 300 with constant wind velocity of 6 m/s. The analysis results show that blade angle 15º gives best possible power.
CONTRIBUTION OF GEOGRAPHICAL INFORMATION SYSTEMS TO THE IDENTIFICATION OF GOODS IMPACTED BY THE CONSTRUCTION OF THE YAOUNDÉ-NSIMALEN HIGHWAY: URBAN SECTION
Authors: TEGNO NGUEKAM Eric Wilson , Foahom Bernard , Mbetjock Camille Kamtchoua
Published: April 2020

Cameroon through its Strategy for Growth and Employment (DSCE), has set up the construction of the Yaoundé-Nsimalen highway project. As part of the assessments of its potential effects on the environment, an ESIA was carried out, according to the framework law on the management of the environment. The acquisition of housing has resulted in an '' anarchic '' installation in the urban and peri-urban area. The construction of a highway as planned overlays on these facilities and poses a problem related to the liberation of spaces previously occupied. The purpose of this study is to identify, locate and classify the impacted goods by the highway construction project through Geographic Information Systems (GIS). Our methodology consisted first, making a satellite identification of the impacted goods, then a field campaign and finally a processing of the data collected. This study was also limited to the identification of two types of property, the buildings and parcels of land. Thus, it has been possible to distinguish and locate six categories of buildings, eight categories of parcels of land defined according to the Cameroon law No. 85/009 of 04 July 1985 on the expropriation for public purpose and the terms of compensation and according to Order No. 0082 / y. 15.1 / MNUH / D of November 20, 1987 laying down the bases for calculating the market value of buildings expropriated for reasons of public utility. The result of this study shows that mapping is a very practical tool for identifying and materializing the impacts that a project may have on components of environment. The GIS revealed a potential disappearance of 1502 building spread over 867 parcels of land.
Treatment of bacterial respiratory infections
Authors: Van Eyk A. D.
Published: April 2020

Acute respiratory tract infections are one of the most common reasons that result in general practitioner consultations. Viruses are the most common cause of both upper- and lower respiratory tract infections, however pneumonia is usually bacterial in origin. When from a bacterial origin, S. pneumoniae non-typical H. influenzae and M. catarrhalis are mostly the cause of acute otitis media, acute bacterial rhinosinusitis and acute exacerbations of chronic bronchitis, while S. pyogenes are usually the presenting organisms in acute pharyngotonsillitis. B. pertussis, C. pneumoniae or M. pneumoniae are common organisms associated with acute bronchitis and community-acquired pneumonia (atypical). Pneumonia is a serious life-threatening condition, and organisms mostly associated with it include S. pneumoniae, S. aureus, H. influenzae type b, K. pneumoniae, Legionella species or P. jirovecii. Common symptoms and signs include coughing, facial pain, fever, nasal congestion, sore throat, dyspnoea, and tachypnoea. Most of the acute uncomplicated respiratory tract infections are self-limiting in nature. It is in many instances a challenge to distinguish between acute bronchitis and pneumonia because of the similarity in presenting symptoms. Antibiotics are in many instances inappropriately prescribed to treat the infections resulting in the burden of antibiotic resistance patterns within the community. Treatment options are usually amoxicillin, amoxicillin-clavulanic acid or the 2nd or 3rd generation cephalosporins.
Burning issues in blood pressure control
Authors: Ker J. A. , Outhoff K.
Published: April 2020

Globally more than 1 billion people have hypertension and it is predicted that because of ageing populations and increasing sedentary lifestyles, this figure will rise to about 1.5 billion by 2025. Elevated blood pressure (BP) is the leading cause of premature death and morbidity due to stroke and ischemic heart disease. Hypertension is also a major risk factor for heart failure, atrial fibrillation, chronic kidney disease, peripheral arterial disease and cognitive decline. This article discusses the current evidencebased treatment guidelines and pressing temporal issues in optimal blood pressure control.
Perioperative Management of Pacemakers (PM) and Implantable Cardioverter Defibrillators (ICD) in South Africa
Authors: Keene A.
Published: April 2020

No abstract available.
A practical approach to perioperative anticoagulation
Authors: Beeton A.
Published: April 2020

No abstract available.
The out-and-about consultation
Authors: Ellis Chris
Published: April 2020

No abstract available.
Understanding Alzheimer disease
Authors: Vally M. , Kathrada F.
Published: April 2020

Alzheimer disease (AD) is a neurodegenerative disorder with an uncertain pathogenesis. It is characterised by symptoms of memory impairment, executive dysfunction and visuospatial impairment. Management goals and interventions should be based on a solid alliance with the patient and family and on thorough psychiatric, neurological and general medical evaluations of the nature and cause of cognitive deficits and associated non-cognitive symptoms. There are currently three cholinesterase inhibitors and one N-methyl-D-aspartate (NMDA) antagonist indicated in the treatment of AD as monotherapy or in combination. Cholinesterase inhibitors remain the first-line therapy in patients with mild to moderate AD, which may stabilise the symptomatic cognitive and functional decline. Other pharmacotherapy options include the use of memantine which may be used by itself or in combination with cholinesterase inhibitors. These treatments are for symptomatic relief and are not disease modifying in preventing the progression of the disease.
Brand innovator versus multisource cefpodoxime in respiratory tract infections: A comparative study
Authors: Snyman J. R. , Medlen C. E.
Published: April 2020

Purpose: In everyday practice clinicians are overwhelmed by claims from the pharmaceutical industry and, due to marketing efforts, they often view generic multisource products with scepticism despite proof and registration by regulatory authorities of bioequivalence. The primary aim of this study was exploratory and aimed to compare the acceptability of generic cefpodoxime (Cepodem®) versus the innovator brand product (Orelox®) in terms of effectiveness, safety and tolerability in a general private practice setting in South Africa in the treatment of upper and lower respiratory tract infections.Methods and patients: Ninety patients were recruited and randomised to receive either product for 10 days after clinical diagnoses of either tonsillo-pharyngitis or rhino-sinusitis or pneumonia.Results: It was demonstrated that both products resulted in similar clinical and bacteriological cure rates with also no difference in tolerability profiles.Conclusion: These findings support the bioequivalence data as submitted for regulatory approval, of the generic Cepodem® translating into clinical effectiveness and argues against the need for a clinical non-inferiority study to demonstrate sameness.
Growing the discipline of family medicine as a counterculture
Authors: Von Pressentin Klaus B.
Published: April 2020

No abstract available.
Optimising the learning environment for undergraduate students in the Department of Family Medicine at Sefako Makgatho Health Sciences University
Authors: Govender I. , De Villiers M.
Published: April 2020

Background: An important determinant of a medical student’s behaviour and performance is the department’s teaching and learning environment. Evaluation of such an environment can explore methods to improve educational curricula and optimise the academic learning environment.Aim: The aim is to evaluate the educational environment of undergraduate students in the Department of Family Medicine as perceived by students.Setting: This descriptive quantitative study was conducted with one group of final-year students (n = 41) enrolled in 2018, with a response rate of 93% (n = 39). Students were in different training sites at SMU.Methods: Data were collected using the Dundee Ready Educational Environmental Measure (DREEM) questionnaire. Total and mean scores for all questions were calculated.Results: The learning environment was given a mean score of 142/200 by the students. Individual subscales show that ‘academic self-perception’ was rated the highest (25/32), while ‘social self-perception’ had the lowest score (13/24). Positive perception aspects of the academic climate included: student competence and confidence; student participation in class; constructive criticism provided; empathy in medical profession; and friendships created. Areas for improvement included: provision of good support systems for students; social life improvement; course coordinators being less authoritarian and more approachable; student-centred curriculum with less emphasis on factual learning and factual recall.Conclusion: Students’ perceptions of their learning environment were more positive than negative. The areas of improvement will be used to draw lessons to optimise the curriculum and learning environment, improve administrative processes and develop student support mechanisms in order to improve students’ academic experience.
I got burnt once (IGBO)
Authors: Ellis Chris
Published: April 2020

No abstract available.
Caregivers of children with diabetes mellitus: challenges of caring for and perceptions of consultations in a South African public sector context
Authors: Dhada B. L. , Blackbeard D. R.
Published: April 2020

Background: Understanding caregivers’ challenges in caring for children with diabetes mellitus (DM) and their perceptions of consultations with the multidisciplinary team (MDT) may be valuable in assisting in achieving control.Methods: Using a qualitative descriptive design, anonymised, transcribed recorded data from semi-structured interviews with a purposive sample of caregivers were thematically analysed in three areas: (a) challenges experienced in caring for their child, (b) feelings around MDT consultations pertaining to helpfulness, support and diabetes education, and (c) suggestions for clinic improvement. University of KwaZulu-Natal ethics committee approval and informed consent were obtained.Results: All caregivers (n = 14) were female with a mean age of 38 years. Total diabetes caring experience was 47.4 years. The primary caregiver was the mother in nine interviews. Ten interviewees were unemployed. The children’s ages ranged from 3 to 15 years with mean age at diagnosis of 6.7 years. Caregivers’ challenges in caring were reflected in two global themes: ‘DM care is difficult’ and needs a ‘process of adjustment’ over time to accept and meet demands. These included emotional, practical, financial, behavioural and social challenges. Caregivers’ feelings regarding overall consultations were mostly positive, including satisfaction. The MDT’s helpfulness and support were perceived as patient-centred and meeting education and care needs. Negative feelings were frustration and boredom. Clinic improvement suggestions included shorter waiting times and seeing the same doctor for continuity of care.Conclusion: Caregivers in South Africa experienced caring for children with DM as difficult, requiring an adjustment process. Perceptions of consultations were mostly positive. Relevant clinic improvements were suggested.
Burning issues in acute heart failure management
Authors: Ker J. A. , Outhoff K.
Published: April 2020

In general, heart failure is the end-stage manifestation of cardiovascular disease and is an important and increasing cause of morbidity worldwide. Acute heart failure, whether of new onset or an exacerbation of chronic heart failure, causes sudden congestion, typically presenting as pulmonary oedema. The mortality associated with acute heart failure is extremely high. Potentially life-saving treatments and other burning issues are highlighted in this review.
An HIV-free generation: review of prevention strategies
Authors: Moodley I.
Published: April 2020

Globally South Africa has the largest HIV epidemic, with an estimated 7.7 million people living with HIV (PLHIV). The burden of HIV in South Africa varies by age, gender and key population groups. Prevalence is highest among adults between the ages of 15 and 49 years and is higher among females than males. The prevalence rate also varies by province with the highest rates observed in KwaZulu-Natal, Free State, Eastern Cape, Mpumalanga and Northwest.While greater access to anti-retroviral treatment (ART) has significantly reduced the number of deaths and new infections, the number of new infections is still relatively high, highlighting the need for prevention.Initial prevention strategies focus on behavioural change through increased education and awareness to ensure safer sex, mainly through peer education, condom distribution and voluntary medical male circumcision (VMMC), all of which are in place with varying degrees of success. More recently newer approaches are being considered such as pre-exposure prophylaxis (PrEP) and treatment as prevention (TasP). The major challenge is still behavioural change.This review sets out to critically evaluate the current and newer approaches. Studies suggest that to achieve greater impact, rather than targeting the general population, prevention strategies should focus on vulnerable populations and in provinces with the highest HIV burden.
An evaluation of male learners’ knowledge, attitudes and practices regarding sexual and reproductive health in rural northern KwaZulu-Natal province
Authors: Rogers Mampho Mochaoa , Mfeka-Nkabinde Gloria , Ross Andrew
Published: April 2020

Background: With a disparate HIV prevalence among young men and women, high rates of teenage pregnancies and a lack of responsible fatherhood, issues of reproductive health among young people need to be urgently addressed. The aim of this research was to assess the knowledge, attitudes and practices regarding sexual and reproductive health among young men in the Bethesda Hospital catchment area of northern KwaZulu-Natal province.Methods: This observational, descriptive cross-sectional study was conducted at six randomly selected high schools within the uMkhanyakude district. All grade 12 male learners ≥ 18 years completed a questionnaire regarding their reproductive health knowledge, attitudes and practices.Results: A total of 279 learners participated in the study with a median age of 20.2 years and a mean knowledge score of 63.8%. Only 28.3% of the learners showed good or excellent knowledge on basic sexual and reproductive health questions; 50.9% believed that girls say ‘no’ to sex when they mean ‘yes’, and 46.2% believed that girls were sexually aroused when dominated by a man. Some 156 (55.9%) of those who were sexually active did not know their current sexual partner’s HIV status. There were significant associations between being brought up in a female-headed family and early sexual debut but not between early sexual debut and paternalistic attitudes to women.Discussion and conclusions: Basic sexual and reproductive health knowledge among the majority of participants was adequate. Patriarchal attitudes of sexual domination were prominent, and these are probably influenced by sociocultural belief systems of traditional masculinity, which are defined and dominated by men. This perpetuates gender inequality and contributes to poor sexual and reproductive health outcomes. Poor health-seeking behaviour and attitude relating to sexually transmitted infections (STIs), and having concurrent multiple sexual partners, puts them and their sexual partners at risk of HIV/AIDS acquisition. Strategies need to be developed to enhance socially acceptable and comprehensive sexual and reproductive health education and services among young men in this area, foster positive attitudes towards women and encourage gender-equal relationships.
A profile of Caesarean sections performed at a district hospital in Tshwane, South Africa
Authors: Govender I. , Steyn C. , Maphasha O. , Abdulrazak A. T.
Published: April 2020

Introduction: Caesarean section (CS) is a common obstetric procedure that prevents neonatal and maternal death when performed correctly if indicated; however, CS can give rise to complications that lead to maternal and perinatal morbidity and mortality. Rates of CS are increasing worldwide, although the World Health Organization (WHO) has indicated an ideal rate of 5–15%. South African CS rates are higher than the ideal.Methods: Maternity records of 2015 were reviewed at Odi District Hospital (ODH) to assess whether ODH complies with the ideal CS rate. In this study, extracted data include date and time of CS, maternal age, parity, gestational age, total number of previous CSs, elective or emergency, indications, anaesthesia used and registration of the surgeon.Results: There were 3 336 deliveries and 1 064 CSs (32%). The majority of women were aged from 19 to 34 years (59%), 72.8% were multiparous and 54% between 37–39 weeks’ gestation. The most common (40.1%) overall and emergency indication was foetal distress. Most CSs were emergencies (61.70%). Most elective CSs were because of a previous CS and spinal anaesthesia was used in 91.73%. Medical officers performed most of the CSs (79.0%) during working hours. The CS rate of 32% was significantly higher than the ideal 5–15% and higher than in other sub-Saharan countries with similar maternal characteristics. Indications for emergency and elective CSs were similar to previous research.Conclusion: The Caesarean section rate at ODH is higher than the recommended rate. Potential CSs therefore need to be evaluated more intensely to assess the true need for surgical intervention.
The Trace Form Over Cyclic Number Fields
Authors: Bolaños Wilmar , Mantilla-Soler Guillermo
Published: April 2020

In the mid 80’s Conner and Perlis showed that for cyclic number fields of prime degree p the isometry class of integral trace is completely determined by the discriminant. Here we generalize their result to tame cyclic number fields of arbitrary degree. Furthermore, for such fields, we give an explicit description of a Gram matrix of the integral trace in terms of the discriminant of the field.
Steiner symmetry in the minimization of the first eigenvalue of a fractional eigenvalue problem with indefinite weight
Authors: Anedda Claudia , Cuccu Fabrizio , Frassu Silvia
Published: April 2020

Let
$\Omega \subset \mathbb {R}^N$
,

$N\geq 2$
, be an open bounded connected set. We consider the fractional weighted eigenvalue problem

$(-\Delta )^s u =\lambda \rho u$
in

$\Omega $
with homogeneous Dirichlet boundary condition, where

$(-\Delta )^s$
,

$s\in (0,1)$
, is the fractional Laplacian operator,

$\lambda \in \mathbb {R}$
and

$ \rho \in L^\infty (\Omega )$
.

We study weak* continuity, convexity and Gâteaux differentiability of the map

$\rho \mapsto 1/\lambda _1(\rho )$
, where

$\lambda _1(\rho )$
is the first positive eigenvalue. Moreover, denoting by

$\mathcal {G}(\rho _0)$
the class of rearrangements of

$\rho _0$
, we prove the existence of a minimizer of

$\lambda _1(\rho )$
when

$\rho $
varies on

$\mathcal {G}(\rho _0)$
. Finally, we show that, if

$\Omega $
is Steiner symmetric, then every minimizer shares the same symmetry.
Optimal Cooperative Path Planning Considering Driving Intention for Shared Control
Authors: Li Mingjun , Song Xiao-lin , Cao Dongpu , Cao Haotian
Published: April 2020

This paper presents an optimal cooperative path planning method considering driver’s driving intention for shared control to address target path conflicts during the driver-automation interaction by using the convex optimization technique based on the natural cubic spline. The optimal path criteria (e.g. the optimal curvature, the optimal heading angle) are formulated as quadratic forms using the natural cubic spline, and the initial cooperative path profiles of the cooperative path in the Frenet-based coordinate system are induced by considering the driver’s lane-changing intention recognized by the Support Vector Machine (SVM) method. Then, the optimal cooperative path could be obtained by the convex optimization techniques. The noncooperative game theory is adopted to model the driver-automation interaction in this shared control framework, where the Nash equilibrium solution is derived by the model predictive control (MPC) approach. Finally, the proposed framework is tested with different driver’s driving intentions to avoid obstacles on a straight road and a curvy road. As a result, the planned path could continuously adapt to the driving intention and various road shapes, and the path conflicts between the human driver and the controller is also decreased by the proposed cooperative path planning method in the game-based shared control framework.