bluuebunny/crossref_metadata_2025 huggingface dataset:
Sound Off! Trade in Your Pendulum for a Personal Spacecraft
Authors: Taylor P. Mark
Published: November 2020

Over my fifteen–year career in mathematics education, I have seen major changes in the way textbooks are written and used as well as in how state standards are written and tested. Many of the mathematics teachers with whom I have spoken are excited about the momentum brought about by the increase in research and the publication of the NCTM Standards documents in 1989, 1991, 1995, and 2000. These include recommendations in curriculum, instruction, assessment, and professional responsibilities. I have witnessed curriculum changes that include shifts in emphasis, inclusion of new topics, exclusion of outdated topics, and the integration of content within high school mathematics courses. Instructional changes have included a shift toward using more hands–on materials at the high school level, an increase in awareness of the role of multiple representations, a shift from occasional use of scientific calculators to frequent use of graphing calculators, and an emphasis on the role of the student as an active learner in the mathematics classroom. Assessment changes include less emphasis on tests as the be–all and end–all of assessment and a shift toward having students explain their reasoning as a part of the assessment process.
A two-decade record of variations in suspended sediment in the Warta River, a lowland river in western Poland
Authors: SKOLASIŃSKA Katarzyna , NOWAK Bogumił , BRADTKE Katarzyna
Published: November 2020

Fluctuations in suspended sediment concentration (SSC) has been investigated in the Warta River (western Poland), based on data obtained for the period 1961–1980 from three gauge stations located in upstream, middle-stream and downstream areas. Over the two decades, the SSC values demonstrated wide fluctuations and an overall increase at each gauge station. No significant correlation was generally observed between SSC and discharge but high SSC was found to follow low discharge and increasing temperature during the summer seasons in some years. Measurements of SSC and discharge were used to estimate total annual suspended sediment load (SSL). SSL values were found to increase downstream along with an increase in discharge. SSC decreases along the river course. However, when it comes to changes over time, SSL variability was mainly determined by SSC changes. The maximum SSC values were primarily caused by anthropogenic factors: the disposal of mine wastewater upstream, river training works, increased urbanisation and the intensification of sewage disposal. Where the river catchment has been greatly affected by anthropogenic factors, a denudation index calculated solely based on SSC and discharge does not appear to reflect the actual denudation rate, and must be treated with caution.
A REMARK ON BOLTZMANN H THEOREM
Authors: CHANG TSUNG-SDEI  ,   中国科学院数学研究所,北京师范大学物理系
Published: November 2020

It is pointed out that the quantum-mechanical Boltzmann H theorem in the restricted sense (i.e. with explicit consideration of the statistics of the particles constituting the system and their interactions) does not lead directly to the distribution laws for the particles among their various states as is commonly believed, but to the equality of the probability for all states belonging to the system as a whole if the system is isolated, (or to the Boltzmann factor for the probabilities of states belonging to a system at constant temperature), in agreement with the result of the generalized quantum-mechanical H theorem as given by Pauli. The distribution laws for the particles among their various states may of course be deduced from the latter.In the course of proof, we have also introduced the following minor improvements:(i) To avoid conservation of energy in microscopic processes which lead to changes in the states of the particles and thus to equilibrium, we let our system be in interaction with a heat reservoir, so that energy may be supplied by or given to it. This is tauto-mount to changing the study of the entropy for an isolated system to that of the free energy for a system at constant temperature.(ii) Interaction energies between the particles which affect the total energy of the system and thus the distribution laws for the particles among their various states are included.
COMPOSITE BEAMS JOINTED BY BOLTS
Authors: KU CHIU-LIN  ,   清华大学
Published: November 2020

In this paper, it is proved that the problem of composite beams jointed by bolts can be solved in terms of certain equivalent continuous beams. The equivalent beam is specified as follows: 1) It consists of supports of the original beam and equivalent supports situated at the points where bolts are used. 2) It is loaded by the given load on the original beam.Then the reactions at the bolts in the original composite beam are equal to a constant C times the reactions at various supports of the equivalent continuous beam. The constant is equal to C=(E′J′-k(EJ+E′J′))/(EJ+E′J′), where EJ and E′J′ are flexaral rigidities of the first and second parts of the composite beam respectively, and k is the distributing ratio of load on the second part.The solution of the problem is then greatly simplified.This method can be generalized for composite beams consisting of more than two parts, on which the given load is not proportionately distributed.
MEASUREMENTS OF ATTENUATION OF SOUND IN FOGGY AIR AT LOW AUDIBLE FREQUENCIES
Authors: WEI YUNG-CHIO  ,   南京大学物理系
Published: November 2020

The anomalous sound absorption in water fog at low audible frequencies observed by Knudsen, Wilson, and Anderson has been further investigated by the method of standing waves.Measurements were made in the frequency range of 25-250 c.p.s. for artificial fogs of several different concentrations and average droplet sizes. Artificial fogs were produced by a specially designed water sprayer and introduced into the measuring tube. The fog inside the main tube was almost turbulent-free and both the droplet size and concentration were made controllable. In order to sample the droplet size, fog droplets were allowed to settle by gravity cn a horizontal vaseline-coated glass disk which was partly inserted in the tube. This disk rotated at a constant speed while photomicrographs were taken with a 16mm. motion picture camera synchronized with an Edgerton's strobolux. The fog concentration was determined by measuring the total liquid water content in a known volume of the foggy air. The fogs thus produced had average radii of 5-9 microns and a concentration 5-14×103/c.c. These measurements were made simultaneously with the acoustic measurement. Standing wave pressure variations along the tube were registered by a logarithmic level recorder, both with and without the fog. The observed attenuation coefficients were computed from the observed first pressure minimum and the first pressure maximum of the standing wave. The maximum attenuation coefficients thus computed varied from 8.8db/sec to 20.8db/sec. The positions of maximum absorption were found to vary from 35 to 50 c.p.s.The theoretical values based on both Oswatitsch's and the modified theory proposed by the present autheor are compared with the experimental values. The experimentally obtained attenuation coefficients due to evaporation and condensation processes are found to be higher than those computed by both theories throughout the lower frequency range but in better agreement with the modified theory than with that of Oswatitsch.
THE CHARACTERISTICS OF PIEZO - ELECTRIC OSCILLATIONS OF NATURAL COLOURED QUARTZ
Authors: LIU MIN-CHICH  ,   中国科学院应用物理研究所
Published: November 2020

The object of the present work is to investigate the characteristics of piezo-electric resonantors which are cut from the natural coloured quartz, and compare the results with those obtained from those plates cut from the ordinary clear quartz in order to see if coloured quartz might be used as piezo-electric material in practice. In this work four points were stressed, they are: (1) the frequency constants of piezo-electric oscillation, (2) its stability, (3) its selectivity and activity and (4) its frequency-temperature coefficient curves. Further more a comparison of the characteristics of oscillations before and after the heat-treatment of the material was made. By the results of these experiments it concludes that the natural coloured quartz plates can be excited into piezo-electric oscillation and serve as piezo-electric resonantors. The frequency constant of a Y-cut plate from coloured quartz is about 2% lower than that of same type cut plate from clear quartz, while the frequency constants of the X-cut plate and the AT-cut plate from the coloured and clear quartz are practically the same. The heat-treatment to the three types cut plates of both kinds of quartz has a definite influence on their frequency. This effect is more pronounced to the coloured quartz plates. Likewise, heat-treatment improves, from the point-view of statistics, the selectivity and activity of oscillation of both kinds of quartz. Finally, the values of some coefficients of stiffness of the coloured and clear quartz were discussed.
A STUDY ON THE DIFFUSION OF CARBON IN γ-IRON BY METHOD OF INTERNAL FRICTION
Authors: KE TING-SUI  , YANG PEN-WEI  ,   (1)东北人民大学物理系,研究生,在中国科学院金属研究所研究实习; (2)中国科学院金属研究所
Published: November 2020

In γ-iron (containing 1.7% of Mn) an internal friction peak was observed around 240℃with a frequency of vibration of about 2 cycles per second. The height of the peak was found to increase with an increase of the carbon content and was found to decrease when the specimen was annealed at an elevated temperature. The activation energy associated with this peak was found to be 34,000±2,000 calories permole which is close to the activation energy of diffusion of carbon in y-iron determined in macro-diffusion experiments. It is concluded, thus, the observed internal frictionpeak is associated with the stress-induced diffusion of carbon in y-iron.The coefficient of diffusion D of carbon in y-iron in the temperature range of 200-260℃ was calculated according to data given by internal friction measurements. When plotted with logD against 1/T, these values of D were found to lie on the same straight line with those values of D in the temperature range of 1000-1200℃ determined in macro-diffusion experiments.The height of internal friction peak appeared to vary with the square of the carbon content in the specimen. This seems to indicate that two carbon atoms are participating in the elementary act associated with the stress-induced diffusion. A preliminary model for the observed internal friction peak was suggested thereupon: Owing to the presence of holes (vacancies) in the crystal lattice, two carbon atoms are apt to form an atomic-pair and this pair produces lattice distortions which are different along three crystallographic directions. Rotation of such an atomic-pair under the action of stress gives rise to internal friction.
EFFECT OF SURFACE RECOMBINATION ON THE PHOTOCONDUCTIVE SPECTRUM OF n-TYPE GERMANIUM (Ⅱ)
Authors: TANG TING-YUAN  ,   中国科学院应用物理研究所
Published: November 2020

The continuity equation of minority carriers in n-type germanium is solved for the stationary case, in which the volume recombination is assumed to be of the recombination-center type and the surface recombination is introduced in the boundary condition. An expression for the photoconductivity is obtained from this solution.By substituting the known absorption data and the volume lifetime of minority carrier in the sample into the expression of photoconductivity and by choosing suitable values of surface recombination velocity, photoconductive spectra are calculated and are compared with the experimental curves. The agreement is satisfactory for wave-lengths greater than 1.2 μ. Below 1.2 μ, the experimental curves fall well below the calculated curves. It is thought that other types of volume recombination may exist.The photoconductive spectra usually have a maximum outside the absorption edge. By measuring the relative height of the maximum, the surface recombination velocity can be obtained. This method is suitable for medium and large values of surface recombination velocity.The photoconductivity drops sharply on both sides of the maximum in case of large values of recombination velocity. In such cases, the energy gap of the semiconductor can be obtained in a simple way. For germanium the energy gap is 0.83 eV for direct transition and 0.635 eV for indirect transition.From this investigation, the energy gap of CdS is reestimated to be 2.53 eV and that of Cu2O greater than 2.10 eV.
THE ROLLING AND RECRYSTALLIZATION TEXTURES OF ARMCO IRON
Authors: TAT LI-CHI  , CHANG SIN-YU  ,   钢铁工业综合研究所
Published: November 2020

A study of the preferred orientations and microstructure of armco iron after cold reduction and recrystallization has been made.The treatments consisted of hot-rolling the material into strips and (1) a cold reduction of 98.8 percent or ( 2 ) two cycles of cold reduction of about 64 percent with an intermediate anneal. All these specimens for recrystallization were treated in hydrogen at 650° and 1000℃.The components after deformation for material (1) were found to be (100) [011] +(112) [110] + (111) [112] . The primary orientations of the specimens treated in a and γ regions were determined as (100) [011] and (111) [112] .The cold rolling textures of material ( 2 ) were found to be the same as those of (1), the deviation angle being larger. The surface texture was different from the texture possessed by inside of the sheet. The microstructure showed the phe-namena of secondary recrystallization for the samples treated at higher temperature.
ULTRAPHOTOMETER USING MAGNETICALLY MODULATED PHOTOMULTIPLIER
Authors: G. O. STRIKER  ,   匈牙利科学院精密量测与仪器制造研究所
Published: November 2020

Theoretical considerations indicate that by applying the Magnephot principle to photomultipliers, a simple and rugged industrial microphotometer may be built in the range of extremely low light intensities. The requirements for a low input impedance and a conservative input signal level can be successfully combined with a satisfactory signal-to-noise ratio without the use of mechanical light chopping. The external-shield method of dark current suppression may be usefully employed to extend the sensitivity limit to lowest light values, limited only by the discontinuous nature of the light flux.Experimental investigation confirmed these assumptions and led to the construction of a sturdy and simple ultra-photometer of inherent electrical stability. The limit of useful sensitivity is around 10-12 Lumen, corresponding to the light collected by a 24" telescope from a star of the 14th order. Experiments with scintillating crystals yielded data about the use of the new instrument as a quantitative sensing device for nuclear radiation. The experimental instrument gave satisfactory performance as to zero stability, independence from leakage currents and the exclusion of dark current without cooling. The use of a.c. amplification assured convenient range-switching and the possibility to amplify the signal further for registration or control purposes. The new ultra-photometer will now be investigated in conjunction with spectrophotometry, astronomic and other low-level photometry as well as the indirect measurement of X-ray and nuclear radiation.
Multi beam hybrid heterodyne interferometry based phase enhancement technology
Authors: Kong Xin-Xin , Zhang Wen-Xi , Cai Qi-Sheng , Wu Zhou , Dai Yu , Xiang Li-Bin ,   College of Instrument Science and Optoelectronic Engineering, Beihang University, Beijing 100191, China,   Key Laboratory of Computational Optical Imaging Technology, Chinese Academy of Sciences, Beijing 100094, China,   Aerospace Information Innovation Institute, Chinese Academy of Sciences, Beijing 100094, China
Published: November 2020

Laser Doppler vibrometer can measure the displacement, velocity, acceleration and other parameters of vibration target. It has the characteristics of non-contact, high precision and long distance. So, it has a great advantage for the vibration measurement in a special working environment, where the target is light and thin, hard to contact, hard to approach. Laser heterodyne interferometry is an important means of detecting the micro vibration. With the development of micro vibration application, the sensitivity of phase measurement is highly required. Traditionally, there are several ways of improving the measurement sensitivity, such as optimizing the heterodyne interference scheme, improving the phase reconstruction algorithm and reducing the noise of key devices and so on. However, based on the analysis of the influence of stray light in the system, it is found that the controllable multi-beam interference can greatly improve the detection capability of the system. Therefore, a phase enhancement technique of multi-beam hybrid interference is proposed to meet the needs of high sensitivity detection of micro vibration. In this paper the physical mechanism and boundary conditions of phase enhancement are investigated in detail, and the quantitative relationship between the boundary conditions and phase enhancement is also analyzed thereby providing a technical reference for the enhancement detection of micro vibration targets. Through the numerical simulation and experimental verification, the following boundary conditions are obtained: the initial phase difference between the correction light and the signal light is π rad and the closer the power values of the two beams, the greater the enhancement effect of the demodulation phase is. The power difference between the two beams designed in the experiment is 1%, which means that detection capability is enhanced by 146 times. It has great application value in the high sensitivity measurement of micro vibration objects. This technology can also enhance the detection capability of heterodyne interference measurement system without changing the existing device index or phase demodulation algorithm.
Manipulations on mechanical properties of multilayer folded graphene by annealing temperature: a molecular dynamics simulation study
Authors: Li Xing-Xin , Li Si-Ping ,   Department of Engineering Mechanics, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
Published: November 2020

Annealing is a commonly used fabrication technology of graphene-assembled materials, which serves as an efficient method to control material properties. In graphene-assembled materials, the multilayer folded configuration of graphene has been widely observed due to the two dimensional characteristic of graphene. However, the manipulation on the mechanical properties of graphene-assembled materials by annealing has not been fully understood yet, especially considering the effect of folded microstructures. In this paper, we focus on the effect of annealing temperature on the mechanical properties of multilayer folded graphene. The dependences of elastic modulus, tensile strength, ultimate strain and fracture toughness on the annealing temperature have been systematically studied by molecular dynamics simulations. Moreover, the mechanisms behind the manipulations by annealing temperature have been revealed combining the structural evolutions obtained from the simulations. Our results indicate that the multilayer folded graphene after annealing under higher temperature exhibits significant reinforcement on its elastic modulus and tensile strength, while its ultimate strain drops instead. The fracture toughness is enhanced only within a certain range of annealing temperature. The controllable mechanical properties are attributed to the formation of interlayer covalent bonds between carbon atoms belonging to adjacent layers during the annealing processing. With the annealing temperature increases, more interlayer crosslinks are observed from simulations, which greatly strengthens the interlayer interaction. For the cases with lower annealing temperature, the folded graphene can be unfolded easily then finally flattened under tensile stretch, and the structural failure originates from the interlayer slippage in the folded area. However, for the cases with higher annealing temperature, the unfolding deformation is prevented since the folded graphene is blocked by much denser interlayer crosslinks, and the origins of structural failure transforms to the intralayer fracture in graphene plane. Considering the intralayer covalent bond interaction is far more powerful than the interlayer van der Waals interaction, the higher annealing temperature will bring higher elastic modulus and tensile strength due to the change on the structural failure mode, but it will sacrifice the ductility at the same time due to the blocked unfolding process of folded area. It is confirmed in our study that the annealing is an effective approach for the synthetic modulation on the stiffness, strength, ductility and toughness of multilayer folded graphene.
Terahertz emission spectrum of polar antiferromagnet Fe2Mo3O8
Authors: Shi Li-Yu , Wu Dong , Wang Zi-Xiao , Lin Tong , Zhang Si-Jie , Liu Qiao-Mei , Hu Tian-Chen , Dong Tao , Wang Nan-Lin ,   International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
Published: November 2020

In polar materials, the transition of electrons in momentum space will change the spontaneous polarization. When excited by femtosecond pulse laser, the transient modulation of the electric polarization will radiate electromagnetic wave at terahertz frequency. In a magnetic ordered system, the coherent excited spin wave radiates electromagnetic waves of the same frequency in the process of precession and relaxation. The investigation of the terahertz emission spectra of these materials not only helps us to understand the ferroelectric and magnetic ordered dynamic processes of materials, but also provides a reference for searching for new terahertz sources. We study the terahertz emission spectrum of the polar antiferromagnet Fe2Mo3O8. Under the pumping of 800 nm laser, electrons in the material are excited across the band gap leading the electric polarization to be ultra-fast modulated. The broadband terahertz excitation spectrum from 0.1 to 3.5 THz is observed, and the direction of the terahertz electric field is along the inherent electric polarization direction of the material. After entering into the magnetic order state, two new single-frequency terahertz oscillations are observed, located at 1.25 THz and 2.7 THz respectively, which correspond to the excitation of the two antiferromagnetic spin waves of Fe2Mo3O8.
NUCLEAR LEVEL SPACING DEDUCED FROM THE RESONANCE ABSORPTION OF NEUTRONS
Authors: Y. H. Yang  ,   华中大学物理系
Published: November 2020

The average nuclear level spacings of In, Ir and Au are estimated from the beta-ray activities induced by the primary photo-neutrons emitted from a Ra+Be source. A Geiger-Muller counter made of aluminum is used for measuring the induced activities. The saturated induced activities for the three elements are found to be 0.665±0.23 0.982±.03l, 0.453±0.21 (no./sec.) respectively. The estimation for the average nuclear level spacings is made in accordance with Breit-Wigner's one level formula, the resnlts being 5.6, 15 and 6 volts for In, Ir, Au respectively. The spacing of Ir is probably somewhat over estimated since the values of the energy and absorption coefficient of the resonance neutron group, used in the estimation, are not very accurate.
ASSUMPTIONS IN SAINT-VENANT'S SOLUTION FOR THE TORSION OF AN ELASTIC CYLINDER
Authors: CHIEN WEI-ZANG  ,   北京清华大学
Published: November 2020

In this paper, it is proved that Saint-Venant's solution for torsion can be obtained from the following simplified assumptions: (?τxz)/(?z)=(?τyz)/(?z)=0. These assumptions are much more simplified than those given by Saint-Venant in 1855, A. Clebsch in 1862, W. Voigt in 1887, and J. N. Goodier in 1937.
Fatigue in Children with Pronated Feet After Aerobic Exercises
Authors: de los Ángeles Gómez-Benítez María , Gómez-Benítez Andrea , Ramos-Ortega Javier , Castillo-López José M. , Bellido-Fernandez Lorena , Munuera-Martínez Pedro V.
Published: November 2020

Background

Sports have a strong influence on current society. Foot posture has been postulated to be a risk factor for overuse injuries; however, the link between foot posture and injuries is unclear. This study aimed to determine whether children with pronated feet become more fatigued after participating in sports tests than those with normal feet.

Methods

One hundred five children aged 10 to 12 years (mean ± SD age, 10.46 ± 0.78 years) participated in the sports tests, which were aerobic-type resistance exercises with six stations at which each child remained for 30 sec. The posture of the foot was evaluated via the Foot Posture Index and the plantar footprint via the arch index and the Clarke angle before and after aerobic-type resistance exercises. Perceived tiredness was evaluated with the Pictorial Children's Effort Rating Table (PCERT) and whether there was pain during or after physical activity.

Results

The variables used to measure foot posture and the plantar arch changed more in the pronated feet, suggesting that the feet undergo more pronation after physical exercise. The neutral feet obtained a mean ± SD PCERT score of 5.46 ± 1.89 and the pronated feet a score of 7.60 ± 1.92.

Conclusions

Children with pronated feet showed more fatigue and foot pain during and/or after physical exercise than those with neutral feet. Foot type could be responsible for the lack of enthusiasm of children toward undertaking healthy activities, and this problem might be solved via appropriate orthopedic treatment.
Vascular plant species diversity of Mt. Etna (Sicily): endemicity, insularity and spatial patterns along the altitudinal gradient of the highest active volcano in Europe
Authors: Sciandrello Saverio , Minissale Pietro , Giusso del Galdo Gianpietro
Published: November 2020

Background

Altitudinal variation in vascular plant richness and endemism is crucial for the conservation of biodiversity. Territories featured by a high species richness may have a low number of endemic species, but not necessarily in a coherent pattern. The main aim of our research is to perform an in-depth survey on the distribution patterns of vascular plant species richness and endemism along the elevation gradient of Mt. Etna, the highest active volcano in Europe.

Methods

We used all the available data (literature, herbarium and seed collections), plus hundreds of original (G Giusso, P Minissale, S Sciandrello, pers. obs., 2010–2020) on the occurrence of the Etna plant species. Mt. Etna (highest peak at 3,328 mt a.s.l.) was divided into 33 belts 100 m wide and the species richness of each altitudinal range was calculated as the total number of species per interval. In order to identify areas with high plant conservation priority, 29 narrow endemic species (EE) were investigated through hot spot analysis using the “Optimized Hot Spot Analysis” tool available in the ESRI ArcGIS software package.

Results

Overall against a floristic richness of about 1,055 taxa, 92 taxa are endemic, of which 29 taxa are exclusive (EE) of Mt. Etna, 27 endemic of Sicily (ES) and 35 taxa endemic of Italy (EI). Plant species richness slowly grows up to 1,000 m, then decreases with increasing altitude, while endemic richness shows an increasing percentage incidence along the altitudinal gradient (attributed to the increased isolation of higher elevation). The highest endemic richness is recorded from 2,000 up to 2,800 m a.s.l., while the highest narrow endemic richness (EE) ranges from 2,500 up to 2,800 m a.s.l. Life-form patterns clearly change along altitudinal gradient. In regard to the life-form of the endemics, the most represented are the hemicryptophytes, annual plants (therophytes) are prevailing at lower altitudes and show a decreasing trend with increasing elevation, while chamaephytes are featured by an increasing trend up to 3,100 m of altitude. Furthermore, the results of the hotspot analysis emphasize the high plant conservation priority areas localized in oro-mediterranean (1,800–2,400 m s.l.m.) and cryo-mediterranean (2,400–2,800 m) bioclimatic belts, in correspondence of the oldest substrates of the volcano.

Conclusions

High plant speciation rate caused by increasing isolation with elevation is the most plausible explanation for the largest active volcano in Europe. The high degree of endemic species on Mt. Etna is linked to its geographical, geological and climatic isolation, all important drivers of speciation acting on the population gene flows. The hot spot map obtained represents a useful support for help environmental decision makers to identify priority areas for plant conservation.
Aspectos problemáticos en torno al consentimiento en los matrimonios por conveniencia en Chile
Authors: Basoalto Riveros Constanza Pamela
Published: November 2020

El fenómeno de los matrimonios celebrados con fines ajenos a la institución matrimonial es ya ampliamente conocido en la sociedad civil. Se trata de matrimonios en los que falta una auténtica voluntad conyugal, y que se han denominado por la doctrina como matrimonios por conveniencia, de complacencia, blancos, entre otras calificaciones. Actualmente, esta temática se ha visto renovada por los numerosos movimientos migratorios que han dado un matiz distinto al debate, y es bajo esa perspectiva desde donde comienza el presente análisis.Este trabajo examina algunos aspectos problemáticos del tema, partiendo desde el inexistente tratamiento legal del fenómeno en Chile, culminando con lo que sería la sanción jurídica del mismo. Al efecto, la autora desarrolla algunas de sus razones en orden a considerar la inexistencia jurídica como posible sanción legal.
Precision Farming Development Centre Hyderabad: The Boon for Local Farmers
Authors: Devi M. Uma , Kaleel Ibrahim , Chaitanya K. , Deepika . , Srinu B. , Chaitanya A. Krishna , Swathi G.
Published: November 2020

Precision farming is the technique of applying the right amount of input (fertilizer, pesticide, water etc.) at the right location at the right time to enhance production, decrease input and/or protect the environment, Site-Specific Crop Management (SSCM), Farming by-the-foot, Farming soils and not fields, Prescription farming, Environmentally-friendly farming & Information-based crop production. Thus, precision farming is an appealing concept and its principles quite naturally lead to the expectation that farming inputs can be used more effectively, with subsequent improvements in profits and environmentally less burdensome production. The precision farming developments of today can provide the technology for the environment friendly agriculture of tomorrow. Especially in the case of small farmers in developing countries like India, precision farming holds the promise of substantial yield improvement with minimal external input use. In order to achieve optimal production with less inputs, Precision Farming Development Centre (PFDC), Hyderabad, Telangana, India, plays important role in Precision farming by reaching local farmers to introduce precision farming techniques. PFDC Hyderabad attracts local farmers with tailor made annual action plans which includes both research and extension part. This study shows how PFDC Hyderabad uplifts both financial and social status of local farmers by introducing them to Precision Farming.
Richness and Diversity of the Edaphic Macrofauna in a Brazilian Seasonally Dry Tropical Forest
Authors: Costa Cássio Ricardo Gonçalves da , Silva Marcos Gomes da , Cunha Rayane Sley Melo da , Sousa Marcia Mayara de , Linhares Anne Carolline Maia , Silva Sonaria de Sousa , Marques Ailson de Lima , Moura Debora Coelho de , Batista Regiane Farias , Lima José Ayron Moraes de
Published: November 2020

The objective of this work was to evaluate the influence of seasonality on the diversity and richness of the edaphic macrofauna during the dry and rainy periods, in an area of Caatinga in the Brazilian semiarid region. Samples were collected in a sample grid, totaling 10 points, spaced 30 meters apart, in rainy and dry seasons. For quantitative assessment of macrofauna, the total number of organisms (species abundance) was measured, according to diversity. The diversity of the soil macrofauna for this research corresponds to the following order: Hymenoptera> Diptera> Aranaea> Orthoptera> Coleoptera, for the rainy and dry periods, with a greater predominance of the order Hymenoptera. The influence of seasonality was observed in relation to the richness and diversity of the region's macrofauna, with marked fluctuations between the rainy and dry periods.
Multiple Protective Roles of Nanoliposome‐Incorporated Baicalein against Alpha‐Synuclein Aggregates
Authors: Aliakbari Farhang , Mohammad‐Beigi Hossein , Abbasi Shahsanam , Rezaei‐Ghaleh Nasrollah , Lermyte Frederik , Parsafar Soha , Becker Stefan , Tafreshi Azita Parvaneh , O'Connor Peter B. , Collingwood Joanna F. , Christiansen Gunna , Sutherland Duncan S. , Jensen Poul Henning , Morshedi Dina , Otzen Daniel E.
Published: November 2020

Nanoparticles are useful for increasing drug stability, solubility, and availability. The small molecule baicalein inhibits fibrillation, and detoxifies aggregates of α‐synuclein (αSN) associated with Parkinson's disease (PD), but it suffers from instability, low solubility and consequent low availability. Here it is demonstrated that incorporation of baicalein into zwitterionic nanoliposomes (NLP‐Ba) addresses these problems. NLP‐Ba inhibits αSN fibril initiation, elongation, secondary nucleation, and also depolymerizes mature fibrils more effectively than free baicalein and prevents soluble αSN aggregates from seeding new fibrils. Importantly, NLP‐Ba perturbs oligomers’ capacity to permeabilize the membrane. The interaction between NLP‐Ba and αSN is confirmed by different biophysical techniques. This nanosystem crosses the blood‐brain barrier in vitro and is effective against rotenone neurotoxicity in vivo. The effect of NLP‐Ba on αSN fibrillation/cytotoxicity is attributed to a combination of free baicalein and empty NLPs. The results indicate a neuroprotective role for NLP‐Ba in decreasing αSN pathogenicity in PD and highlight the use of nanoliposomes to mobilize poorly soluble hydrophobic drugs.
Etanercept or Methotrexate Withdrawal in Rheumatoid Arthritis Patients in Sustained Remission
Authors: Curtis Jeffrey R. , Emery Paul , Karis Elaine , Haraoui Boulos , Bykerk Vivian , Yen Priscilla K. , Kricorian Greg , Chung James B.
Published: November 2020

Objective

Patients with rheumatoid arthritis (RA) in whom remission is achieved following combination therapy with methotrexate plus etanercept face an ongoing medication burden. This study was undertaken to investigate whether sustained remission achieved on combination therapy can be maintained with either methotrexate or etanercept monotherapy, as assessed following discontinuation of one or the other medication from the combination.

Methods

Of the 371 adult patients with RA who received combination therapy with methotrexate plus etanercept, remission (defined as a Simplified Disease Activity Index [SDAI] score of ≤3.3) was sustained in 253 patients through a 24‐week open‐label period. These 253 patients then entered a 48‐week, double‐blind period and were randomized to receive either 1) methotrexate monotherapy (n = 101), 2) etanercept monotherapy (n = 101), or 3) methotrexate plus etanercept combination therapy (n = 51). Patients who subsequently experienced disease‐worsening received rescue therapy with the combination regimen at the same dosages as used in the initial run‐in period. The primary end point was the proportion of patients in whom SDAI‐defined remission was maintained without disease‐worsening at week 48 in the etanercept monotherapy group as compared to the methotrexate monotherapy group. Secondary end points included time to disease‐worsening, and the proportion of patients in whom SDAI‐defined remission was recaptured after initiation of rescue therapy.

Results

Baseline demographic and clinical characteristics of the RA patients were similar across the treatment groups. At week 48, SDAI‐defined remission was maintained in significantly more patients in the etanercept monotherapy group than in the methotrexate monotherapy group (49.5% versus 28.7%; P = 0.004). Moreover, as a secondary end point, sustained SDAI‐defined remission was achieved in significantly more patients who received combination therapy than in those who received methotrexate monotherapy (52.9% versus 28.7%; P = 0.006). Time to disease‐worsening was shorter in those who received methotrexate monotherapy than in those who received etanercept monotherapy or those who received combination therapy (each P < 0.001 versus methotrexate monotherapy). Among the patients who received rescue therapy, SDAI‐defined remission was recaptured in 70–80% in each treatment group. No new safety signals were reported.

Conclusion

The efficacy of etanercept monotherapy was superior to that of methotrexate monotherapy and similar to that of combination therapy in maintaining remission in patients with RA. SDAI‐defined remission was recaptured in most of the patients who were given rescue therapy. These data could inform decision‐making when withdrawal of therapy is being considered to reduce treatment burden in patients with well‐controlled RA.
DLR Equations and Rigidity for the Sine‐Beta Process
Authors: Dereudre David , Hardy Adrien , Leblé Thomas , Maïda Mylène
Published: November 2020

We investigate Sineβ, the universal point process arising as the thermodynamic limit of the microscopic scale behavior in the bulk of one‐dimensional log‐gases, or β‐ensembles, at inverse temperature β > 0. We adopt a statistical physics perspective, and give a description of Sineβ using the Dobrushin‐Lanford‐Ruelle (DLR) formalism by proving that it satisfies the DLR equations: the restriction of Sineβ to a compact set, conditionally on the exterior configuration, reads as a Gibbs measure given by a finite log‐gas in a potential generated by the exterior configuration. In short, Sineβ is a natural infinite Gibbs measure at inverse temperature β > 0 associated with the logarithmic pair potential interaction. Moreover, we show that Sineβ is number‐rigid and tolerant in the sense of Ghosh‐Peres; i.e., the number, but not the position, of particles lying inside a compact set is a deterministic function of the exterior configuration. Our proof of the rigidity differs from the usual strategy and is robust enough to include more general long‐range interactions in arbitrary dimension. © 2020 Wiley Periodicals, Inc.
Simple Solution‐Processed Approach for Nanoscale Coverage of Perovskite on Textured Silicon Surface Enabling Highly Efficient Perovskite/Si Tandem Solar Cells
Authors: Wang Jiayuan , Gao Chao , Wang Xin , Wang Yangrunqian , Cheng Zhendong , Liu Hong , Shen Wenzhong
Published: November 2020

Existing methods toward the preparation of perovskite deposited on textured silicon surfaces are technically complicated for perovskite/Si monolithic tandem solar cells (TSCs). Herein, a handy solvent engineering approach of introducing starch additive in MAPbI3‐based one‐step spin coating at room temperature is reported. The effect of different starch contents in perovskite precursor solution on morphological, structural, optical, and photovoltaic properties of the perovskite films is investigated. The starch enhances the solution viscosity and establishes hydrogen bonds with CH3NH3+, leading to the formation of almost same perovskite crystal structure films suitable for textured silicon surfaces. The perovskite film with a starch concentration of 5 wt% realizes full coverage on the textured silicon surface with an average thickness around 600 nm. Both the perovskite film and corresponding plane solar cell exhibit stable crystal structure and device performance due to the starch molecules located at the perovskite grain boundaries to lock the water molecules. The potential of pairing the yielded quasiconformal nanoscale coverage of perovskite layers with textured silicon surfaces is evaluated, and the uniform light absorption in perovskite layers and good match of the current density in perovskite/Si monolithic TSCs, with the best‐calculated cell efficiency exceeding 29%, are demonstrated.
New (and Old) Monomers from Biorefineries to Make Polymer Chemistry More Sustainable
Authors: Al‐Naji Majd , Schlaad Helmut , Antonietti Markus
Published: November 2020

This opinion article describes recent approaches to use the “biorefinery” concept to lower the carbon footprint of typical mass polymers, by replacing parts of the fossil monomers with similar or even the same monomer made from regrowing dendritic biomass. Herein, the new and green catalytic synthetic routes are for lactic acid (LA), isosorbide (IS), 2,5‐furandicarboxylic acid (FDCA), and p‐xylene (pXL). Furthermore, the synthesis of two unconventional lignocellulosic biomass derivable monomers, i.e., α‐methylene‐γ‐valerolactone (MeGVL) and levoglucosenol (LG), are presented. All those have the potential to enter in a cost‐effective way, also the mass market and thereby recover lost areas for polymer materials. The differences of catalytic unit operations of the biorefinery are also discussed and the challenges that must be addressed along the synthesis path of each monomers.
Dynamic concentration of the triangle‐free process
Authors: Bohman Tom , Keevash Peter
Published: November 2020

The triangle‐free process begins with an empty graph on n vertices and iteratively adds edges chosen uniformly at random subject to the constraint that no triangle is formed. We determine the asymptotic number of edges in the maximal triangle‐free graph at which the triangle‐free process terminates. We also bound the independence number of this graph, which gives an improved lower bound on the Ramsey numbers R(3, t): we show , which is within a 4 + o(1) factor of the best known upper bound. Our improvement on previous analyses of this process exploits the self‐correcting nature of key statistics of the process. Furthermore, we determine which bounded size subgraphs are likely to appear in the maximal triangle‐free graph produced by the triangle‐free process: they are precisely those triangle‐free graphs with density at most 2.
Green Synthesis of Iron Nanoparticles for Investigation of Biofilm Inhibition Property
Authors: Majumdar Moumita , Khan Shamim Ahmed , Nandi Nishithendu Bikash , Roy Shaktibrata , Panja Anindya Sundar , Roy Dijendra Nath , Misra Tarun Kumar
Published: November 2020

Green metal nanoparticles (NPs) have emerged as efficient biofilm inhibitors.Citrus macroptera(CM) fruit extract mediated iron (Fe) NPs,i. e., CM‐FeNPs were thus synthesized for studying biofilm inhibition property. The shape (spherical), size (12 nm), and crystallinity (α‐Fe0bcc) of the CM‐FeNPs were confirmed by studying mainly Transmission Electron microscopy (TEM) and X‐ray Diffractometer (X‐RD) tools. The particles inhibit biofilm growth of a bacteriaPseudomonas aeruginosa(P. aeruginosa) by inhibiting the functions of extracellular polymeric substances (EPS) and virulence factors to ∼80 %. Scanning Electron microscopy (SEM) images of the bacteria in presence of the CM‐FeNPs (4600 nM) in combination with azithromycin (AZI) evidence the inhibition of biofilm growth >80 %. Molecular docking studies support experimental findings and result significant negative binding energies (e. g., isoplatydesmine/LasR: −8.25 kcal/mole, isoplatydesmine/MvfR: −7.56 kcal/mole) from bioactive molecules/biofilm proteins interactions. Thus, CM‐FeNPs could be considered as potential biofilm inhibitors, and as an alternative to antibiotic drugs.
Encapsulation of Porphyrin‐Fe/Cu Complexes into Coordination Space for Enhanced Selective Oxidative Dehydrogenation of Aromatic Hydrazides
Authors: Zhang Dongxu , Du Peiyao , Liu Jia , Zhang Ruizhong , Zhang Zhen , Han Zhengang , Chen Jing , Lu Xiaoquan
Published: November 2020

The encapsulation of specific nanoentities into hollow nanomaterials derived from metal organic frameworks has attracted continuous and growing research attentions owing to their unique structural properties and unusual synergistic functions. Herein, using the phase transformation of uniform rhombi dodecahedron ZIF‐67, hollow nano‐shell with a well‐defined morphology is successfully prepared. Particularly, the iron‐oxygen complex, that is formed by the interaction between TCPP‐Fe/Cu (TCPP = tetrakis(4‐carboxyphenyl)‐porphyrin) and oxygen, can be acted as an ideal proton acceptor for practical organic reactions. Considering the unique adaptability of hollow ZIFs (named HZ) to the transformation of encapsulated TCPP‐Fe/Cu bimetallic catalytic active sites, a heterogeneous catalyst (defined as HZ@TCPP‐Fe/Cu) through morphology‐controlled thermal transformation and rear assemble processes is designed and constructed. Under heterogeneous conditions, HZ@TCPP‐Fe/Cu serves as a multifunctional molecular selector to promote the oxidative dehydrogenation of different aromatic hydrazide derivatives with high selectivity toward primary carbon among primary, secondary, and tertiary carbons that are unachievable by other traditional homogeneous catalysts. The high catalytic activity, selectivity, and recyclability of the catalyst proposed here are attractive advantages for an alternative route to the environmentally benign transformation of aromatic hydrazides to aromatic azobenzene.
Carrier‐Free Platinum Nanomedicine for Targeted Cancer Therapy
Authors: Wang Changping , Li Lin , Zhang Song , Yan Yang , Huang Quan , Cai Xiaopan , Xiao Jianru , Cheng Yiyun
Published: November 2020

Numerous nanomedicines have been developed to improve the efficiency and safety of conventional anticancer drugs; however, the complexities in carrier materials and functional integration make it challenging to promote these candidates for clinical translation. In this study, a facile method to prepare carrier‐free anticancer nanodrug with inherent bone targeting and osteoclastogenesis inhibition capabilities is reported. Phytic acid, a naturally occurring and nontoxic product, is reacted with cisplatin to form uniform nanoparticles of different sizes. The prepared nanoparticles possess high drug loading and pH‐responsive drug release behaviors. Phytic acid in the nanomedicine ensures high bone targeting and osteoclastogenesis inhibition, and the released platinum drugs triggered by tumor extracellular acidity eradicate tumor cells. The nanomedicine around 100 nm shows high anticancer activity and much reduced side effects in a subcutaneous breast cancer model when compared with cisplatin. In addition, it shows high accumulation at osteolytic lesions, and efficiently inhibits tumor growth and tumor‐associated osteolysis in a bone metastatic breast cancer model. Here, a facile and efficient strategy to prepare carrier‐free nanomedicines with high anticancer drug loading, inherent bone targeting, and osteoclast inhibitory activities for cancer therapy is provided.