bluuebunny/crossref_metadata_2025 huggingface dataset:
Are Circumscribable Quadrilaterals Always Inscribable?
Authors: Shin Joseph
Published: January 2021

A quadrilateral that can be circumscribed about a circle is said to be circumscribable. A quadrilateral that can be inscribed in a circle is said to be inscribable. How would you answer this question: Are circumscribable quadrilaterals always inscribable? On reflection it seems that squares are circumscribable as well as inscribable. However, what happens if the figure is not so “regular”? After a moment's thought, you will discover that some circumscribable quadrilaterals are not inscribable.
Clubs: What is Mu Alpha Theta?
Authors: Huneke Harold V.
Published: January 2021

Mathematics clubs have been a part of the mathematics scene for many years. They come in all shapes and sizes with varied activities such as offering regular programs presented by students or mathematicians from universities or industry, participating in contests, providing tutoring services, taking field trips, sponsoring mathematics field days for junior high schools, and so on. The purpose of all these activities is to promote interest and scholarship in mathematics through activities outside the classroom.
Clubs: Students Write Mathematics Tournament
Authors: Foerster Paul A.
Published: January 2021

Each year schools in Texas host their own mathematics tournaments. Ours has two unique features. One is an “Olympiad” event, written and graded by our teachers, in which contestants are marked on their work as well as on the correctness of their answers. The other feature is that the remainder of the tournament is organized, written, and graded by the students of our mathematics club. This article concentrates on the student-run part of the tournament, in particular the writing of the tests.
Kurt Gödel, Mathematician and Logician
Authors: Lenz Gerald E.
Published: January 2021

From the pages of recent history…
The Ninth U.S.A. Mathematical Olympiad
Authors: Greitzer Samuel L.
Published: January 2021

The Ninth U.S.A. Mathematical Olympiad was held on 6 May 1980. At the suggestion of members of the Olympiad Committee, the number of contestants was increased over previous years by adjusting the cutoff score from the Annual High School Mathematics Examination. As a result, 121 students (from over 400 000) were invited instead of the usual 100. In addi
A Stem-Leaf Plot: An Approach To Statistics
Authors: Macdonald A. D.
Published: January 2021

A versatile new technique to help organize data.
Reading Graduated Scales
Authors: Hall Lucien T.
Published: January 2021

Measurement is a basic skill in mathematics education. It involves the ability to read a graduated scale. Teaching students to read graduated scales is probably an overlooked or taken-for-granted part of instruction. Since so many different instruments exist and each has its own individualized graduated scale, it is necessary to teach students the process for reading those points on a graduated scale that are not numerically marked.
Sequences of Product Differences
Authors: Litwiller Bonnie H. , Duncan David R.
Published: January 2021

Some nice examples of arithmetic patterns that can he verified with elementary algebra.
Making A Better Beer Glass
Authors: Hoffer Alan R.
Published: January 2021

What this country needs is a better beer glass. Will you please help me design one?
Geometry For Pie Lovers
Authors: Fisher William
Published: January 2021

It is unfortunate, but students in high school algebra and geometry classes of- tentimes do not get to see some very useful applications of their studies. I’m thinking specifically of problems that in- volve finding maxima and minima. These types of problems are generally thought of as part of calculus and are usually avoided until then.
Geomegy Or Geolotry: What Happens When Geology Visits Geometry Class?
Authors: Reesink Carole J.
Published: January 2021

Very often when studying three-dimen- sional geometry and polyhedra, students don't feel the topic can be useful to anyone. They do become enthusiastic about their study when they see some applications. A good example is in mineralogy or crystal chemistry. The geometry of a mineral crystal is one of the principal ways of identifying the types of mineral one has found (along with the chemical composition). Many people are aware that diamonds and graphite are made of the same element; however, it is the crystal structure that differentiates the two. Geologists are constantly called on to identify miner-als found in geological exploration.
Mysteries Of Proof
Authors: Marino George
Published: January 2021

Many students enjoy mysteries with the intensity that they hate proofs. Yet mysteries and proofs can almost be isomorphic. Consider the following two problems. Problem I is a typical geometry proof, and problem 2 is a murder mystery. The solutions are so alike that their diagrammatic forms will coincide when displayed together on an overhead projector.
The Self-Distributive Property
Authors: Franz Edgar A. , Meek Katrina F.
Published: January 2021

One of the results of the new math is that most high school students of algebra know the commutative laws for addition and multiplication of real numbers, the associative laws for addition and multiplication, and the distributive law of multiplication over addition.
Some Strategy Games Using Desargues’s Theorem
Authors: Salisbury Andrew John
Published: January 2021

The use of games in the classroom can “transform the classroom from an assemblage of passive spectators into a vibrant laboratory of active participants” (Krulik 1977). One technique that 1 have employed is to modify the shape of the pattern used for tic-tac-toe and then to offer students opportunities to develop new strategies. Krulik used a board containing nine cells in which the players attempt to place three Xs or three Os in a row (fig. 1).
Algebraic Formulas For Areas Between Curves
Authors: Gabai Hyman
Published: January 2021

Korean secondary school students preparing for college learn about the existence of a simple algebraic formula for finding the area bounded by a parabola and a line. This approach does not seem to be well known among American students. Whereas the derivations of formulas developed in this paper rely on integration by parts, algebra students could use the formulas without proofs.
An Analysis of Two Car-Buying Strategies
Authors: Bland Paul , Givan Betty
Published: January 2021

The purpose of this article is to present a problem in applied mathematics that can be used as a study project by a secondary school student. The problem is within the grasp of students at the secondary level who have studied sequences and series. We have chosen the problem because its solution brings into play such varied topics as beginning algebra, the theory of interest, and the theory of sums of series of finite length.
Sharing Teaching Ideas: Harmonic Series Revisited
Authors: Beimler Gerald
Published: January 2021

Sharing Teaching Ideas offers practical tips on the teaching of topics related to the secondary school curriculum. We hope to include classroom-tested approaches that offer new slants on familiar subjects for the beginning and the experienced teacher. Please send an original and four copes of your ideas to the managing editor for review.
The Caterer's Problem
Authors: Krause Eugene F.
Published: January 2021

How to teach problem solving? My usual unimaginative approach is to throw out a lot of problems and ask the students to work on them. Recently I tried something a little different with a class of preservice and in-service middle school teachers. We plunged into a problem that, to the best of my knowledge, was unsolved and treated it as a class research project. For an interval of several weeks we devoted a few minutes each period to progress reports on it. During this time.
Mathematics and the Imagination
Authors: Jacobs Harold R.
Published: January 2021

Several years ago an article appeared in the editorial pages of the Los Angeles Times in which the author reminisced about his mathematics education. Although he was a gifted student and had progressed beyond calculus, his fondest memories were of an old arithmetic book. It was not what the book taught that had captivated him but, rather, how it taught.
Challenges for Enriching the Curriculum: Algebra
Authors: Giambrone Tom M.
Published: January 2021

Many students in our algebra courses need the challenge of exploring problems that must be solved by a method that involves the creation of a new (for those students) technique rather than the application of a known algorithm. The problems presented in this article are designed to challenge these gifted students while giving them opportunities to use algebraic concepts.
Challenging Applications: Problems in the “Raw”
Authors: Agnew Jeanne , Keener Marvin S. , Finney Ross L.
Published: January 2021

Where and when should our gifted high school students develop problem-solving abilities? Here and now! The basic questions encountered by a problem solver at any level are these: Where do I begin? What is the real question? What do I know that helps? What more do I need to know? How can I find it? How can I apply all this to the problem? Have I made valid assumptions?
Clubs: Algebra and a Super Card Trick
Authors: Davis Edward J. , Middlebrooks Ed
Published: January 2021

Here is a fascinating card trick that can be explained and justified using first-year algebra. We have used this trick with high school classes and mathematics clubs as a motivational device and sometimes as a challenge to students to find or finish the algebraic justification. This procedure makes a good example of the power of mathematics to unmask seemingly complex situations and, therefore, is a good device for teachers to “keep up their sleeves” for some auspicious occasion or a time when interest is lagging. Some related procedures can be found in the bibliography.
The Harmonic Triangle: Opportunities for Pattern Identification and Generalization
Authors: Stones Ivan D.
Published: January 2021

In the search for nonroutine material for a class on the history of mathematics, I became interested in the patterns that can be discovered within number triangles. “Looking for patterns” is a mathematical activity that not only is challenging and fun for students but also helps develop problem-solving techniques.
Some Variations on a Mathematical Card Trick
Authors: Markowitz Lee M.
Published: January 2021

In “A Simple Mathematical Model of a Neat Card Trick,” John Elliott (1982) explained a trick that has appeared in several books (Patton 1968*; Scarne 1950). It is an intriguing activity that can be generalized in several ways. Let's first review the procedures, and then see how we can generalize from them.
Inversion in a Circle: A Different Kind of Transformation
Authors: Cohen Martin P.
Published: January 2021

Geometric transformations (e.g., reflections, rotations, translations) are now included in many secondary school geometry textbooks in an effort to strengthen students’ facility with coordinate geometry and their algebraic manipulative skills.
Triangular Numbers: The Building Blocks of Figurate Numbers
Authors: Olson Melfried , Goff Gerald K. , Blose Murray
Published: January 2021

Figurate or polygonal numbers have been studied since the Greek era. Recent publications in mathematics education have reflected their continuing attraction (Hartman 1976; Smith 1972; Weaver 1974).
SoundOFF: A Shortage of Mathematics Teachers in Houston
Authors: Say Elaine
Published: January 2021

The time had come to act. A shortage of teachers in a few teaching fields— specifically mathematics, science, bilingual education, and special education prompted the Houston Independent School District to go beyond traditional lockstep salary schedules to attract teachers in shortage fields. In a single year, all Texas universities were not certifying a sufficient number of mathematics teachers to fill the vacancies in this urban, predominantly minority district alone.
Al-Khwarizmi
Authors: Arndt A. B.
Published: January 2021

I enjoy introducing my mathematics classes to the history of mathematics and science. It is a subject they don't seem to encounter anywhere else, not even in their history courses, and it is one of the few topics that span that wide and culturally divisive gap between science and art in our society.
Sharing teaching ideas: A “Metric Review Show”
Authors: Barnett David
Published: January 2021

Sharing Teaching Ideas offers practical tips on the teaching of topics related to the secondary school curriculum. We hope to include classroom-tested approaches that offer new slants on familiar subjects for the beginning and the experienced teacher. Please send an original and four copies of your ideas to the managing editor for review.
Modeling with Difference Equations: Two Examples
Authors: Wapner Leonard M.
Published: January 2021

Mathematics can stand alone without its applications. The extent to which applications are taught at the secondary level is somewhat arbitrary; nevertheless, I believe that mathematical modeling is both an enjoyable and highly instructive experience for students. Great care should be taken to insure that the models presented are comprehensible and relevant.
Sharing teaching ideas: Generating Primitive Pythagorean Triples: A Computer Solution
Authors: Szczepanski Ronald
Published: January 2021

Sharing Teaching Ideas offers practical tips on the teaching of topics related to the secondary school curriculum. We hope to include classroom-tested approaches that offer new slants on familiar subjects for the beginning and the experienced teacher. Please send five copies of your ideas to the managing editor for review.
Microcomputer-assisted discoveries: A Computer-Based Investigation in Algebra
Authors: Winter M. J.
Published: January 2021

Finding and classifying positive integral solutions to the problem is appropriate for beginning and advanced algebra classes. The computer does the “work” of finding the solutions, but students will get a great deal of practice in algebraic manipulation as they analyze the solutions, searching for patterns.
SoundOFF: Cooperation in Mathematics Education
Authors: Pollak H. O.
Published: January 2021

Once again, we are experiencing a time of ferment in mathematics education. A plethora of special committees and commissions is at work on the subject, many individuals, both inside and outside of mathematics education, are expressing their views, the newspapers contain many pertinent headlines and editorials, and a number of bills are pending in Congress.
Sharing teaching ideas: Triangular Differences
Authors: Pinkerton Kenny
Published: January 2021

Sharing Teaching Ideas offers practical tips on the teaching of topics related to the secondary school curriculum. We hope to include classroom-tested approaches that offer new slants on familiar subjects for the beginning and the experienced teacher. Please send five copies of your ideas to the managing editor for review.
The Summer Olympic Games: A Mathematical Opportunity
Authors: Ewbank William A.
Published: January 2021

“In the Spring a young man's fancy lightly turns to thoughts of love,” wrote Tennyson, but this spring other events will claim his attention (and hers)— the summer Olympic Games! The 1984 Olympiad will be held in our own back yard (Los Angeles), and it can offer many interesting topics for investigation by the mathematics class.
College Entrance Mathematics in the Year 2000
Authors: Maurer Stephen B.
Published: January 2021

What will the college preparatory mathematics program look like in the year 2000? I shall try to tell you.
Mainstreaming Visually Handicapped Students in Mathematics Classes
Authors: Awad M. Michael , Wise Joe L.
Published: January 2021

Integration of blind and sighted students at the high school level is becoming a common practice. Section 504 of the Higher Education Act, which became law in June 1972, provides that no student may be denied admission to an educational institution because of visual impairment. The educational community thus has both a legal and a moral obligation to provide education for the blind.
Microcomputer-assisted discoveries: Understanding the Central Limit Theorem
Authors: Thomas David A.
Published: January 2021

“Microcomputer-assisted Discoveries” offers tips for using the microcomputer in novel ways to improve the teaching of mathematics. Please send five copies of your ideas to the managing editor for review.
125 Kids + 4 Months’ Prep + 7 Computers = 3 Great Days
Authors: Wiatt Joyce
Published: January 2021

Do you want your students to use a computer but don't know what to have them do or how to organize the activities? Here is the story of how 125 seventh graders had three days of hands-on computer experience with very little wasted time and great success and kept up with their other work as well!
Sharing teaching ideas
Authors: Hanson J. Robert
Published: January 2021

“Sharing Teaching Ideas” offers practical tips on the teaching of topics related to the secondary school curriculum. We hope to include classroom-tested approaches that offer new slants on familiar subjects for the beginning and the experienced teacher. See the masthead page for details on submitting manuscripts for review.
Mathematics Contests
Authors: Kahanec Frank
Published: January 2021

Motivating students to become more involved with mathematics can be a troublesome everyday problem. Mathematics contests geared to your student population can be one way to overcome this difficulty. The Forest View Mathematics Department has sponsored and encouraged students’ participation in the American Invitational Mathematics Examination, the Santa Clara contest, and the ICTM computer competition. In addition, we have held three school contests of our own! The purpose of this article is to acquaint you with some of our past experiences and give you some ideas for future contests.
Using Microcomputers to Solve Probability Problems
Authors: Haigh William E.
Published: January 2021

Probability theory is that branch of mathematics that is concerned with calculating the probability of outcomes of experiments. For instance, when a die is rolled, we say that the probability of rolling a 1 is 1/6. We do not actually roll the die, but we are able to compute the probability of rolling a 1. After a large number of tosses with an unbiased die. we would expect that 1 6 of the time the top face would be a 1.
Soundoff: Attention and Interest—are You Teaching Without Them?
Authors: Sherman Helene J.
Published: January 2021

The views expressed in the “Soundoff” editorials do not necessarily reflect the views of the Editorial Panel of the Mathematics Teacher or the National Council of Teachers of Mathematics. Readers are encouraged to react to these editorials by writing to the author, with copies to the Mathematics Teacher for consideration in “Reader Reflections.” Please double-space all letters that are to be considered for publication. Editorials from readers are welcomed.
Microcomputer-assisted mathematics: Graph Many Functions, Part 2
Authors: Kimberling Clark
Published: January 2021

Talented mathematics students like stories about geniuses. They like to know what the geniuses were doing when they were teenagers.
Polyominoes: An Unsolved Problem
Authors: Hollingsworth Caroline
Published: January 2021

Although a double-six set of dominoes contains twenty-eight different dominoes, they are indistinguishable if we turn them face down. Dominoes have only one shape (fig. 1). Similarly, we can find just one monomino (fig. 2). But, beginning with trominoes, we find more than one shape. Trominoes have two shapes (fig. 3), and tet- rominoes have five (fig. 4).
New Directions in Two-Year College Mathematics
Authors: Albers Donald J.
Published: January 2021

Twenty-four leaders in American education met at Menlo College in Atherton, California, in July 1984 to discuss the state of mathematics in two-year colleges. At the conference, which was sponsored by the Alfred P. Sloan Foundation, twenty-two papers were presented and discussed.
How Well Do Students Write Geometry Proofs?
Authors: Senk Sharon L.
Published: January 2021

Throughout the history of American education, learning to write proofs has been an important objective of the geometry curriculum for college-bound students. At the same time proof writing has also been perceived as one of the most difficult topics for students to learn. Until recently, the extent of students’ difficulties with writing proofs has been largely a matter of conjecture, for little research has been conducted in this area.
Soundoff: The Impact of Computer Science on School Mathematics
Authors: Ralston Anthony
Published: January 2021

Recently NCTM sponsored a conference on “The Impact of Computing Technology on School Mathematics.” Its report (Corbitt 1985), published in the April issues of the Mathematics Teacher and Arithmetic Teacher should be of interest to many teachers of secondary school mathematics. My topic here, however, is not the report but rather a related topic that is only lightly touched on in it. I am concerned with the impact of computer science, not computing technology, on secondary school mathematics.
The American Junior High School Mathematics Examination
Authors: Butts Thomas , Mientka Walter E.
Published: January 2021

The First Annual American Junior High School Mathematics Examination (AJHSME) will be held on 10 December 1985.
Sharing Teaching Ideas
Authors: Boling Bruce A. , Hornsby E. John
Published: January 2021

“Sharing Teaching Ideas” offers practical tips on the teaching of topics related to the secondary school curriculum. We hope to include classroom-tested approaches that offer new slants on familiar subjects for the beginning and the experienced teacher. See the masthead page for details on submitting manuscripts for review.
How Many Triangles?
Authors: Moser James M.
Published: January 2021

Because the statement of the problem has a very appealing simplicity—it is very succinct, lacks nuances and tricky conditions, and is easy to understand—one might assume that the solution would be equally forthright and clear.
Problem Solving in Geometry—A Sequence of Reuleaux Triangles
Authors: Smart James R.
Published: January 2021

A Reuleaux (pronounced “rue-low”) triangle is an example of a curve of constant width. The distance between parallel tangents is the same no matter which direction is used. A Reuleaux triangle ABC can be constructed (see fig. 1) by starting with an equilateral triangle ABC with sides of length w and drawing arcs of circles connecting two vertices, with the third vertex as center. Figure 1 also shows two pairs of parallel tangents. The length of the side of the equilateral triangle is the constant width for the associated Reuleaux triangle.
Central Tendency and Dispersion: The Essential Union
Authors: Kelly Ivan W. , Beamer James E.
Published: January 2021

Few people would doubt that the main reason that mathematics is taught in the schools is because of its usefulness in everyday life. When one lists the mathematics with which an informed citizen comes in contact, basic skills in statistics are often included (Willoughby 1981). NCTM's (1980, 21) An Agenda for Action concludes that “emerging programs that prepare users of mathematics in nontraditional areas of application may no longer demand the centrality of calculus that has traditionally been demanded for all students.” Certainly. the increased importance accorded to probability and statistics would be considered a part of these nontraditional applications. An earlier report by NCTM (1972, 674), “Mathematical Competencies and Skills Essential for Enlightened Citizens,” included the ability to “determine mean, median, and mode for given numerical data” among its list of forty-eight competencies. A publication of the Council for Basic Education (Willoughby 1981, 34) reports that “another basic skill is collecting, organizing, and interpreting data.”
Mathematical Diagnosis with the Microcomputer: Tapping a Wealth of Potential
Authors: Ronau Robert N.
Published: January 2021

Authorities in the field of mathematical diagnosis have documented that diagnostic information is an essential and integral component of mathematics instruction (Ashlock 1976; Brueckner and Bond 1955; Buswell and Leonore 1926; Reisman 1972; and Underhill 1977). Yet partly because of time constraints and classroom-management difficulties, teachers often neglect formal diagnosis. This article presents a few examples of mathematical diagnosis by microcomputer and suggests possible future considerations for this field.
Bottles and Balloons—an Adventure in Problem Solving
Authors: Miles Marion
Published: January 2021

Finding word problems is not the easiest task of mathematics teachers. Basic practical questions often degenerate into boring exercises, and whimsical puzzles are sometimes deemed too outlandish to pursue. Sometimes, however, a real situation arises that stimulates discussion beyond the limits of the textbook so that problem-solving techniques are sharpened, and the end of class comes all too soon.
An Application of Quadratic Equations to Baseball
Authors: Eisner Milton P.
Published: January 2021

In baseball, the primary objective of each team is to have the greatest winning percentage in its division at the end of the season. During the season, daily standings list the teams in order of decreasing winning percentages. Beside each team's percentage is the number of games it is behind, a measure of how many games that a team trails the team with the greatest winning percentage. For example, consider the standings of National League teams on the morning of 8 August 1984, as shown in table 1.
Soundoff: Developmental-Studies Mathematics: Developmental or Review?
Authors: Gordon John T.
Published: January 2021

Developmental-studies mathematics is the set of skills that students must possess if they are to be sucessful in beginning college-level mathematics. In most colleges and universities, elementary algebra from the secondary school curriculum is a major part of developmental-studies mathematics. Some arithmetic, or some intermediate algebra, or some of both is also commonly included. Although this content is studied by most college-bound students before they enter their last two years of high school, over 60 percent of all students nationally who enter a community college are required to take developmental-studies mathematics (Griffin 1981). Similarly, in many of the larger universities, this statistic is over 50 percent (Whitesitt 1982).
The Method of Finite Differences: Some Applications
Authors: Guillotte Henry P.
Published: January 2021

The method of finite differences is a powerful tool and can be used in many different settings. The method will be discussed and some applications, familiar and unfamiliar, will be shown.
Soundoff: Let's Eliminate Precalculus
Authors: Connors Edward A.
Published: January 2021

Mathematicians select their terminology quite carefully. Despite this diligence, however, mathematical terminology is still deficient at times. Terminology that is difficult may be unavoidable, but that which is ambiguous, deceptive, or meaningless should be discarded. In this spirit, I'll settle for a quick and permanent discard of the term precalculus. And while we are examining the term precalculus, let's also look at precalculus courses.
Turning Landslides into Cliff hangers: An Analysis of Presidential Election Returns
Authors: Duncan David R. , Litwiller Bonnie H.
Published: January 2021

The 1980 U.S. presidential election is widely perceived to have been a landslide. If one considers the electoral-vote totals (489 for Reagan; 49 for Carter), “landslide” seems an apt description. Popular-vote totals (43 899 248 for Reagan; 35 481 435 for Carter) depict a more competitive contest. The plurality (8 417 813) is still, however, substantial.
Modeling the Cost of Homeownership
Authors: Vest Floyd
Published: January 2021

This article presents an investigation of the cost of homeownership by constructing a mathematical model with refinements and illustrates an important type of problem solving with calculators, which falls in line with recommendations found in An Agenda for Action (1980, 1, 4).
Rational Functions: Ignored Too Long in the High School Curriculum
Authors: Hornsby E. John , Cole Jeffery A.
Published: January 2021

“Rational functions? Gee, I've never had to teach that topic before. How do I approach it?”
Microcomputer-Assisted Mathematics: Polynomial Equations Revisited
Authors: Sullivan Jillian C. F.
Published: January 2021

Although solving polynomial equations is important in mathematics, most high school students can solve only linear and quadratic equations. This is because the methods for solving cubic and quartic equations are difficult, and no general methods of solution are available for equations of degree higher than four. However, numerical methods can be used to approximate the real solutions of polynomial equations of any degree. Because they involve a great deal of computation they have not traditionally been taught in the schools. Now that most students have access to calculators and computers, this computational difficulty is easily overcome.
Virtual Reconstruction of the Eastern Part of Moscow Bely Gorod Relief by Means of GIS Software
Authors: Entin Andrey
Published: January 2021

Virtual reconstruction of an urban historical landscape over a relatively large area requires the reconstruction of historical land surfaces. To solve this problem one needs to obtain a detailed spatial data on the Earth surface elevation for a certain historical period as well as the information about the way it changed over time. The reconstruction can be performed using different software. One of the convenient options is to use geographic information systems (GIS) since this approach assumes work with georeferenced data “by default” thus providing for easier combinations with other reconstruction components. The article describes the creation of digital relief models (DRMs) of the eastern part of Moscow Bely Gorod reflecting the state of the land surface in the 16th, 17th and 18th centuries via GIS software (MAG, SAGA, QGIS). Input data for this research are contours from 1:2000 topographic plans and generalized materials of archaeological sources. Using this basis as well as GIS analysis methods, three gridded DRMs (one for each epoch) have been constructed. These DRMs are suitable for use within the GIS environment and for export to other software.
Impacts of Controlled Forest Fires on Soil Properties in Gadchiroli Forest Circle, Central India
Authors: Kamble Rahul
Published: January 2021

Forest is an important ecosystem service to human beings. In recent decades the forest is facing tremendous pressure from anthropogenic activities. One of the activities is the burning of forest floor for easy collection of non-timber forest produce. As a result of this number of incidences of forest fires has increased in the tribal-dominated area of the world. These forest fires have adverse impacts on soil properties which will ultimately in the long term have impacts on the forest ecosystem. Taking into consideration this fact this study was attempted to assess the impacts of controlled forest fires on the physicochemical properties of forest soil in the Gadchiroli forest circle of Central India. To assess the impacts six sampling sites from the forest where identified from the study area where no previous forest fire history was recorded in that season. Initial soil sampling before controlled forest fire was carried out in summer 2019 by quartering method in the topsoil layer (1-5 cm). A controlled forest fire was carried out in the same area. The soil was prepared for soil analysis and analysed by adopting standard methods for bulk density, water holding capacity, pH, electrical conductivity, organic carbon, and organic matter. Results revealed that forest fires increase the bulk density of soil, at 50% (n = 3) sampling locations water holding capacity got reduced down; whereas, at other half increased in capacity was observed. In the case of soil pH 66% (n = 4) sample reported increased in soil pH and at other reduction in soil pH was recorded. Except at one sampling location electrical conductivity was reduced. A similar trend was also noticed for organic carbon and organic matter. Bulk density and water holding capacity will have long term impacts; whereas, pH, electrical conductivity, organic carbon and organic matter will have short term impacts. Furthermore, in those sampling locations where forest fire does not occur in the last 2-3 years organic carbon and organic matter content of the soil is high. Thus, measures to be taken to reduce forest fires activities by incorporating an effective forest fire management system at a place by incorporating fire load management subsystem and fire suppression subsystem.
An investigation of monthly variation of different physicochemical parameters of dairy industry effluent
Authors: Patil Nilam Sarjerao , Kurhekar Jaya Vikas
Published: January 2021

ABSTRACT           Industrialization no doubt enhances the productivity, but also results in release of toxic substances into the environment, creating health hazards. Dairy industry ranks as one of the most polluted industries in India. For cleaning and washing procedures, dairy industry plants generate large volumes of waste water, which is 2.5 times milk volume processed. Dairy effluent contains high load of organic matter. This study was aimed at assessing the monthly variation of different physicochemical parameters of effluent like pH, Temperature, Turbidity, Electrical Conductivity, Chemical Oxygen Demand, Biological Oxygen Demand, Total Solids, Total Dissolved Solids, Total Suspended Solids, Chlorides, Sulfates, Oil & Grease, Proteins, Lipids etc. The pH was recorded for values between 7.3 to 8.2 whereas overall mean value was 7.7±0.37 (S.D.) in all month’s data collected which is ambient for the microbial population to grow. Maximum temperature was reported in May (33°C) while lowest value was reported in December (24°C). Mean value of turbidity was recorded as 762±207 NTU. Maximum EC value was reported in January (650 µS/cm) while minimum value was reported in May (354 µS/cm). BOD values reported were between 268 to 950 mg/lit. Maximum BOD values were reported in August and October while minimum was reported in the month of July. Mean value was recorded at 597±208 mg/lit. COD mean value was recorded at 2184±417 mg/lit. Maximum COD values were observed during August and September while minimum during February to April. TDS was noted down to be between 960 to 1362 mg/lit. TS mean value was around 1412 ± 108 mg/lit. TSS was found to be between 245 to 365 mg/lit during the year 2013-14. Maximum TSS value was reported in November and September while minimum in March. Maximum chloride value was reported in March (562 mg/lit) while minimum in September (256 mg/lit). Mean value of sulfate was 247 ± 98 mg/lit. Mean value for oil and grease was recorded as 163 ± 44 mg/lit. Maximum protein value was reported in November (260 mg/lit) while minimum in the months of May and September (154 mg/lit). Mean value of lipid was recorded to be 600±63 mg/lit indicating obvious variation during batches. The present study has been aimed at procuring dairy industry effluents & characterizing them for different parameters in order to check the fluctuation in organic loads.
Solvent‐Regulated Electronic Structure and Morphology of Inorganic Hole Injection Layers for Efficient Quantum Dot Light‐Emitting Diodes
Authors: Wu Qianqian , Cao Fan , Kong Lingmei , Yang Xuyong
Published: January 2021

Inorganic charge transport layers (CTLs) have been proven to be effective for improving the stability of electroluminescent devices. However, the effective regulation of electronic structure for solution‐processed inorganic CTLs is still challenging by doping or interface engineering, and the film morphology is usually poor due to surface aggregation. Herein, the energy level and mobility of inorganic phosphomolybdic acid (PMA) hole injection layers (HILs) are regulated by adjusting the polarity of solvents, and the resulting inorganic HILs with proper electronic structure act as an energy ladder to better promote hole injection, thereby achieving balanced carrier transport in quantum dot light‐emitting diodes (QLEDs). Meanwhile, the surface morphology of the inorganic PMA film is also improved using solvents with high boiling points, which minimizes the surface tension and is conducive to the formation of smooth and pinhole‐free films. As a result, the devices using PMA dissolved in n‐butanol with a lower polarity exhibit a peak external quantum efficiency (EQE) of 19.2%, which is 3.6 times higher than that of QLEDs using PMA obtained from acetone solvent with a higher polarity. Herein, a general method for the deposition of high‐quality HILs for the fabrication of solution‐processed inorganic functional layers and optoelectronic devices is provided.
Dynamic characteristics of the volatile cloudy zone in a gas–solid fluidized bed with hydrocarbon liquid spray
Authors: Tian Sihang , Sun Jingyuan , Yang Yong , Yang Yao , Huang Zhengliang , Wang Jingdai , Yang Yongrong
Published: January 2021

In a gas–solid fluidized bed with continuous hydrocarbon liquid spray, a volatile “cloudy zone” could be formed, defined as a dynamically steady liquid‐affected zone, including droplets, wet particles, and the gas which passes through the zone. A new flow pattern with the dynamic coexistence of cloudy zone and non‐cloudy zone (gas–solid zone), is accordingly established. The temperature, particle concentration, and particle velocity fields are measured in real‐time via infrared thermography and particle imaging velocimetry, respectively. Results show that the area and range of central position of the cloudy zone illustrate a heavier fluctuant trend with the increasing velocity of liquid spray, and the main frequency of area fluctuation is close to that of the bubble rising. Moreover, the particle concentration and particle velocity in the cloudy zone are lower than those in the non‐cloudy zone, breaking the conventional symmetrical distributions of hydrodynamic parameters of particles in a gas–solid fluidized bed.
Multimorbidity burden and dementia risk in older adults: The role of inflammation and genetics
Authors: Grande Giulia , Marengoni Alessandra , Vetrano Davide L. , Roso‐Llorach Albert , Rizzuto Debora , Zucchelli Alberto , Qiu Chengxuan , Fratiglioni Laura , Calderón‐Larrañaga Amaia
Published: January 2021

Introduction

We investigate dementia risk in older adults with different disease patterns and explore the role of inflammation and apolipoprotein E (APOE) genotype.

Methods

A total of 2,478 dementia‐free participants with two or more chronic diseases (ie, multimorbidity) part of the Swedish National study on Aging and Care in Kungsholmen (SNAC‐K) were grouped according to their multimorbidity patterns and followed to detect clinical dementia. The potential modifier effect of C‐reactive protein (CRP) and apolipoprotein E (APOE) genotype was tested through stratified analyses.

Results

People with neuropsychiatric, cardiovascular, and sensory impairment/cancer multimorbidity had increased hazards for dementia compared to the unspecific (Hazard ration (HR) 1.66, 95% confidence interval [CI] 1.13‐2.42; 1.61, 95% CI 1.17‐2.29; 1.32, 95% CI 1.10‐1.71, respectively). Despite the lack of statistically significant interaction, high CRP increased dementia risk within these patterns, and being APOE ε4 carriers heightened dementia risk for neuropsychiatric and cardiovascular multimorbidity.

Discussion

Individuals with neuropsychiatric, cardiovascular, and sensory impairment/cancer patterns are at increased risk for dementia and APOE ε4, and inflammation may further increase the risk. Identifying such high‐risk groups might allow tailored interventions for dementia prevention.
Pd@CeO2‐catalyzed cyanation of aryl iodides with K4Fe(CN)6·3H2O under visible light irradiation
Authors: Wang Shengyu , Wang Jianqiang , Pan Junyi , Liu Cheng , Gong Xubin , Guo Cheng
Published: January 2021

Cyanation of aryl iodides is still challenging work for chemical researchers because of harsh reaction conditions and toxic cyanide sources. Herein, we have developed a new protocol based on the combination of the catalyst Pd@CeO2, nontoxic cyanide source K4[Fe (CN)6]·3H2O, and driving force visible light irradiation. The reaction is operated at relatively moderate temperature (55°C) and exhibits good catalytic efficiency of product aryl nitriles (yields of 89.4%). Moreover, the catalyst Pd@CeO2 possesses good reusability with a slight loss of photocatalytic activity after five consecutive runs. The reaction system based on the above combination shows a wide range of functional group tolerance under the same conditions. Reaction conditions such as temperature, time, the component of catalyst, and solutions are optimized by studying cyanation of 1‐iodo‐4‐nitrobenzene as model reaction. According to these results, the possible mechanism of Pd@CeO2‐catalyzed cyanation of aryl iodides under visible light irradiation is proposed based on the influence of visible light on the catalyst and reactant compounds. In all, we provided an environmental and economic method for preparation of aryl nitriles from cyanation of aryl iodides based on the goal of green chemistry for sustainable development.
Resorcin[4]arene‐based Cu(I) binuclear and mononuclear complexes as efficient catalysts for azide‐alkyne cycloaddition reactions
Authors: Qin Qian , Xu Guo‐Hai , Liu Ying‐Ying , Ma Jian‐Fang
Published: January 2021

In this study, three fascinating resorcin[4]arene‐based Cu(I) complexes, named [CuCl (TPC4R)] (1), [CuBr (TPC4R)] (2), and [Cu2I2(TPC4R)] (3) were prepared by using a pyrimidine‐functionalized resorcin[4]arene ligand (TPC4R). In1and2, two Cu(I) ions were linked by two TPC4R and two Cl−(or Br−) anions to form binuclear units. The adjacent units were extended into supramolecular layers through H bonds. In3, two Cu(I) ions were connected by one TPC4R and two I−anions to form a mononuclear complex. The mononuclear units were connected by hydrogen bonds to produce a supramolecular chain. Significantly,1and2exhibit high efficiency and universality for azide‐alkyne cycloaddition reactions in the synthesis 1,2,3‐triazoles andβ‐OH‐1,2,3‐triazoles. It has been found that the amount of catalyst, solvent type and reaction temperature have considerable influences on the activities of catalytic systems. The conversions of catalysts1and2could reach 99% for most of the selected substrates. It was found that after repeatedly used for 4 times, the catalytic activity of1did not decrease apparently.
Association of Higher Hydroxychloroquine Blood Levels With Reduced Thrombosis Risk in Systemic Lupus Erythematosus
Authors: Petri Michelle , Konig Maximilian F. , Li Jessica , Goldman Daniel W.
Published: January 2021

Objective

Hydroxychloroquine (HCQ) has a primary role in the prophylaxis and treatment of systemic lupus erythematosus (SLE) and may be protective against thrombosis in SLE. Optimal weight‐based dosing of HCQ is unknown. This study was undertaken to examine the usefulness of HCQ blood monitoring in predicting thrombosis risk in a longitudinal SLE cohort.

Methods

HCQ levels were serially quantified from EDTA whole blood by liquid chromatography–tandem mass spectrometry. The mean HCQ blood levels calculated prior to thrombosis or until the last visit were compared using t‐tests between patients with and those without thrombosis. Pooled logistic regression was used to analyze the association between rates of thrombosis and HCQ blood level. Rate ratios (RRs) and 95% confidence intervals (95% CIs) were calculated.

Results

In 739 patients with SLE, thrombosis occurred in 38 patients (5.1%). The mean ± SD HCQ blood level was lower in patients who developed thrombosis versus those who did not develop thrombosis (720 ± 489 ng/ml versus 935 ± 580 ng/ml; P = 0.025). Thrombosis rates were reduced by 13% for every 200‐ng/ml increase in the most recent HCQ blood level (RR 0.87 [95% CI 0.78–0.98], P = 0.025) and by 13% for mean HCQ blood level (RR 0.87 [95% CI 0.76–1.00], P = 0.056). Thrombotic events were reduced by 69% in patients with mean HCQ blood levels ≥1,068 ng/ml versus those with levels <648 ng/ml (RR 0.31 [95% CI 0.11–0.86], P = 0.024). This remained significant after adjustment for confounders (RR 0.34 [95% CI 0.12–0.94], P = 0.037).

Conclusion

Low HCQ blood levels are associated with thrombotic events in SLE. Longitudinal measurement of HCQ levels may allow for personalized HCQ dosing strategies. Recommendations for empirical dose reduction may reduce or eliminate the benefits of HCQ in this high‐risk population.
Improvement of luminescence properties of NaYF4:Yb3+/Er3+ upconversion materials by a cross‐relaxation mechanism based on co‐doped Ho3+ ion concentrations
Authors: Chung Jong Won , Kwak Minseok , Yang Hyun Kyoung
Published: January 2021

NaYF4:Yb3+/Er3+/Ho3+ nanophosphors were successfully synthesized using a solvothermal method and with various concentrations of Ho3+ ions. The crystal structure, grain size, morphology, and luminescence properties were analyzed by X‐ray diffraction, field‐emission scanning electron microscopy, and photoluminescence measurements. All samples were crystallized as a cubic structure; it was confirmed that all samples exhibited strong green emission and weak red emission generated at a particular level of the activated ions. The strongest upconversion fluorescence intensity was observed in the Ho3+ and Er3+ ions co‐doped NaYF4 materials with a Ho3+ ion concentration of 0.005 mol. Only the green fluorescence intensity at the 542 nm centre increased strongly due to the 4S3/2→4I15/2 energy transfer. This increase in upconversion fluorescence intensity at a selected wavelength was described as a cross‐relaxation mechanism due to the addition of Ho3+ ions.
Major ion chemistry of two cratonic rivers in the tropics: Weathering rates and their controlling factors
Authors: Samanta Anupam , Tripathy Gyana Ranjan , Pradeep Aswin T. , Mandal Anirban
Published: January 2021

Continental weathering plays a dominant role in regulating the global carbon cycle, soil chemistry and nutrient supply to oceans. The CO2‐mediated silicate weathering acts as a major CO2 sink, whereas sulphuric acid‐mediated carbonate dissolution releases CO2 to the atmosphere–ocean system. In this study, dissolved major ions and silica concentrations of two tropical (Damodar and Subarnarekha) river systems from India have been measured to constrain the type and rate of chemical weathering for these basins. The total dissolved solids (TDS) of these rivers, a measure of total solute supply from all possible sources, are about 2–3 times higher than that of the global average for rivers. Mass balance calculations involving inverse modelling estimate that 63 ± 11% of total cations are derived from rock weathering, of which 27 ± 7% of cations are supplied through silicate weathering. The sulphide‐S concentrations are estimated by comparing the water chemistry of these two rivers with that of a nearby river (Brahmani) with similar lithology but no signatures of sulphide oxidation. The outflows of Damodar and Subarnarekha rivers receive 17% and 55% of SO4 through sulphide oxidation, respectively. The sulphide oxidation fluxes from the ore mining areas, such as upper Damodar (0.52 × 109 mol/yr) and lower Subarnarekha (0.66 × 109 mol/yr) basins, are disproportionally (~9 times) higher compared to their fractional areal coverage to the global drainage area. The corresponding CO2 release rate (2.84 × 104 mol/km2/yr) for the Damodar basin is lower by five times than its CO2 uptake rate (1.38 × 105 mol/km2/yr). The outcomes of this study underscore the dominance of sulphide oxidation in controlling the dissolved chemical (cationic and sulphur) fluxes.