bluuebunny/crossref_metadata_2025 huggingface dataset:
Adsorption Isotherms and 13C Solid-state NMR Study of Hazardous Organic Compounds Sorbed on Coal Fly Ash
Authors: Netzel Daniel A. , Miknis Francis P.
Published: November 2020

Fly ash is a by-product from the combustion of coal. The 1985 annual US production was estimated to be about 1 x 108 metric tons. The utilization of fly ash during the 1980s remained stable at about 25% per year. Because of its pozzolanic properties, nearly 50% of the utilized fly ash is consumed in the production of cement and concrete. The vast quantity of fly ash that is not being used and its availability throughout the country and worldwide have motivated research for new uses in commerce and industry. Little is known of the organic adsorbent properties of fly ash. However, if they are found to be favorable, the potential commercial applications of the adsorptive characteristics of fly ash could include its use as an adsorbent sandwich for organics in combination with landfill or other dump-site liners, in traps for organics in waste waters, in filters for organics in process air streams, and as a stabilizer for organic wastes in drums. Variables that may affect the adsorbability of the fly ash towards organics in water include temperature; solution pH; and interactions between solute molecules and fly ash, and between solvent molecules and fly ash. Thus, there is an essential need to characterize each coal fly ash type to enable potential correlation between coal fly ash structural properties and the effectiveness of the adsorption characteristics of coal fly ash for immobilizing organic hazardous waste compounds. The composition and properties of pulverized fly ash depend on the type of coal burned and the nature of the combustion process. Thus, fly ashes from different origins may have significantly different sorption properties towards organic compounds of environmental interest. Eastern and western coal fly ashes differ significantly in their physical and chemical properties. The major minerals found in coal fly ash are α-quartz (SiO2), mullite (3A12O3 ·2SiO2), hematite (Fe2O3), magnetite (Fe3O4), lime (CaO), and gypsum (CaSO4·2H2O). Little is known of the coordination state and distribution of siliceous and aluminous material in coal fly ashes. Most siliceous and aluminous materials in fly ash are amorphous and thus are not detected or quantified by X-ray techniques.
27Al NMR Study of the Hydrolysis and Condensation of Organically Complexed Aluminum
Authors: Thomas Fabien , Masion Armand
Published: November 2020

Aluminum is the most abundant metal of the Earth’s crust, of which it represents approximately 8%, ranking after oxygen and silicon. It exists mainly as oxides. In terrestrial environments, aluminum commonly exists as secondary (authigenic) hydroxide or aluminosilicate minerals, mainly clays. These minerals are highly insoluble at neutral pH. However, aluminum occurs in detectable amounts in natural waters, due to leaching of the soil minerals in acidic conditions. Soil acidity may have a natural origin, such as an acidic (silicic) mother rock, melted snow, dissolved carbonic acid, or biologically generated organic acids. During the past two decades, it has been demonstrated that one of the major origins of increased aluminum mobilization and transport in forested soils is introduction of strong acid through atmospheric sulfur and nitrogen deposition. It has also been shown that aqueous aluminum is the biogeochemical link between atmospheric pollution and damage caused to tree roots and aquatic organisms such as plankton, crustaceans, insects, and fish. Biological studies have shown that the different aluminum species exhibit various toxicities: the most toxic are the monomeric and the polynuclear species; complexation with organic acids results in low toxicity. The significance of aluminum to human health has long been regarded as negligible. There is a possible link between high-level aluminum contamination by renal dialysis or hemodialysis, and neurodegenerative health disorders such as Parkinson’s or Alzheimer’s diseases, but the part played by aluminum is not clear. However, since aluminum salts are used on an industrial level as coagulants and flocculants in water treatment, the aluminum concentration and speciation in drinking water deserve careful monitoring. Because of the specific toxicity of the aluminum species, there has been considerable concern in the past two decades over the speciation of aqueous aluminum present in soils and aquatic systems. To this end, several techniques have been developed in order to partition the aluminum species. The most common among them are chromatographic separation and categorization methods such as timed ferron reaction, and computational methods derived from thermodynamic equilibrium constants. However, significant discrepancies between the results have been noticed, and attributed to the dramatic interference of organic and inorganic anions in the Al fractionation.
Preparation of Low-Carbon Sediments from the Mississippi River and Certain Tributaries for Solid-state CPMAS 13C NMR Analysis
Authors: Leenheer Jerry A. , Maciel Gary E.
Published: November 2020

The nature of organic carbon in aquatic sediments and soils with low carbon contents and significant contents of paramagnetic elements such as iron and manganese is difficult to assess by solid-state, cross-polarization magic angle spinning (CPMAS) 13C nuclear magnetic resonance (NMR) spectrometry because of the inherent low sensitivity of 13C NMR analyses, and band broadening and sensitivity losses caused by paramagnetic elements. Other investigators have addressed this problem in the analysis of soils by enriching the organic carbon content by flotation, by magnetic separation of paramagnetic minerals, and by chemical reduction of iron by stannous chloride and sodium dithionite. In this study, they found that satisfactory 13C NMR spectra could be obtained if the C/Fe ratio was greater than 1 wt%. Each of the physical and chemical treatments used to increase the C/Fe ratio resulted in losses of organic matter and changes in the nature of organic matter through physical fractionation and chemical alteration. Suspended stream sediments frequently have equivalent contents of organic carbon and sesquioxide coatings with which the organic matter is associated. These sesquioxide coatings consist predominantly of iron and manganese oxyhydroxides that cause problems with NMR analyses. In this chapter we describe a method to enrich organic matter and remove iron and manganese from low-carbon sediments sampled from the Mississippi, Illinois, and Ohio Rivers with minimal loss and alteration of the organic matter. The second objective is to characterize the sedimentary organic matter by 13C NMR using recent advances that increase instrument sensitivity. Suspended and bed sediments were collected during a sampling cruise on the Mississippi River during May–June 1990. Fine bed sediments were collected in depositional regions of the river or tributaries with a pipe dredge. Suspended silts were collected using a continuous-flow centrifuge operated on board the Research Vessel Acadiana. Both bed sediments and suspended silts were freeze-dried prior to additional treatment procedures and NMR analyses. A flow chart of selective mineral dissolution procedures is presented in Figure 17.1. The acid pyrophosphate treatment6 was placed first in the sequence to remove calcium and magnesium minerals that would form insoluble oxalates in the following extraction.
Lessons about Learning as a Community
Authors: Rogoff Barbara , Bartlett Leslee
Published: November 2020

Throughout the past century, U.S. parents, scholars, and educators have debated how to help children learn in schools. This book contributes to the discussion by presenting ideas about how children can learn in a community organized to foster their learning. Our ideas stem from participation in an innovative public school that prioritizes instruction that builds on children’s interests in a collaborative way, where learning activities are planned by children as well as adults, and where parents and teachers not only foster children’s learning but also learn from their involvement with the children. Despite some notable experiments to make changes in formal school instruction, the routines of U.S. schooling have remained quite stable across the past century, with the following characteristics: . . . • Being compulsory for all children . . . . . . • Segregating children from the daily activities of the adults in their community . . . . . . • Isolating several dozen children with a single adult charged with their instruction . . . . . . • Grouping children according to their birthdates to provide large numbers of children with standard instruction in a step-by-step fashion . . . . . . • Isolating skills from their integrated use in productive activities . . . . . . • Attempting to motivate children by grading their performance . . . The familiarity of these aspects of schooling have led many adults to assume that these characteristics are necessary to learning in general. It is natural to take for granted the accustomed ways of doing things. As people continue to search for arrangements that communities can use to foster the next generation’s development, efforts to try different arrangements to aid children’s learning are very important, especially as times change. The particular form taken by U.S. schools in the 1900s is only one configuration of possible solutions to the question of how to help children learn the skills that they will need as they mature. Formal, compulsory schooling is a brief experiment in the history of human learning.
Coming Home to School
Authors: Turkanis Carolyn Goodman , Bartlett Leslee
Published: November 2020

The continuing involvement of parents and of children from before they enter school to after graduation contributes to the commitment and comfort of this learning community. In the younger grades, there are a lot of little siblings that visit. These preschoolers will later be OC students—and they already feel that they belong and don’t want to leave when their parents need to go. Leslee remembers an enchanting two-year-old who would come in with her older brother. Soon she was a student in Leslee’s classroom—and recently she was interviewed as an OC graduate for a BBC film about the OC. One four-year-old whose big sister was in Leslee’s class just couldn’t wait to have Leslee as his teacher, so his mother hired Leslee to take him to a museum one summer day so he would be satisfied to have Leslee as his teacher now. Three-year-olds join in their older sisters’ and brothers’ classroom celebrations; they dance around on the playground, holding hands with kids that are two years older—the little ones are part of the community already. By the time their first day of kindergarten arrives, they and the teachers begin the school year feeling that they are in the company of friends and thinking of school as a place that is known, comfortable, and loved. For OC students, school is not a place that you have to go, but a place that you want to go. Recently, two little boys came into school after a weekend, and Leslee said, “Hi, how was your weekend?” and one said “Too long! I wish the weekend was just so quick, so I could get back to school.” John Hayes, as a parent, reflected on the importance of enjoyment of learning in this school community: . . .I am a product of traditional education in Utah which served me well and prepared me to be competitive in higher education. When I compare the reluctance with which my three grade-schoolers view the ending of school, however, to the ultimate jubilation associated with the last day of school that I experienced as a child, I understand clearly why I opt for this educational alternative for my children. . . .
Caring Conversations
Authors: Cryns Theresa , Osborne Marilyn
Published: November 2020

One thing that characterizes the OC is the respectful way OC teachers talk with kids. When two former OC teachers who had moved and now teach in different schools viewed a videotape of one of them teaching, the other was struck with how, after many years apart from each other, they still talk to kids the same way. Respectful conversations happen in the OC and in other schools where many exceptional teachers reach out and make connections with students. An OC teacher recounted an event that illustrates the contrast with other ways of interaction: . . . When a junior high school counselor came to register the kids in my room for junior high the next year, there was not an available table where she could sit with a small group. So I said, “Just a minute, I'll get you a space.” I asked a few kids who were working together at a table if we could use it for a while and then they could have it back. We teased each other a little and then the kids packed up their supplies and moved to work on the floor. The counselor said, “Is that how you talk to kids usually?” I said yes. She told me that in her school adults didn't treat kids like that at all— “There's hardly anyone who would have fun with kids, or even ask them for the table.” I was so stunned, I asked her what she would have done in that situation. She said she would have told them to just “move out, I need the table.” So there would have been no conversation. I asked her if that was the way the whole school interacted with children, and she said there was one person who talked just like me, and it turned out to be a former OC co-oper who now teaches there. . . . If the classroom structure allows conversations, people can learn to converse with respect. Children themselves can play a role in helping adults communicate with them.
Risking Saying "I Don't Know"
Authors: Slotnik Joanne , Johnston Marilyn
Published: November 2020

To learn, teachers need to be willing to take risks. Although they are classroom leaders, they don’t have to know it all. When we had our 20-year reunion of former and current OC teachers, one former OC teacher commented that admitting what she did not know to her teaching colleagues at her new school made her uncomfortable. Others pointed out that even as new OC teachers, saying “I don’t know” sometimes felt too risky. With more experience in the OC, however, they gained the confidence necessary to comfortably admit when they were uncertain or lacking knowledge. We began speculating about the sources of our initial discomfort. One teacher described how her own child’s teacher, in another school, felt compelled to maintain the appearance of always knowing exactly what she was doing even when she herself had many questions. She felt the need to demonstrate that her class was in control and that the kids were progressing at the same rate as those in the other classes. Without the support of other teachers, she could not disclose that she had much to learn. We speculated that a basic tenet of the OC—that learning is a process—encourages people to admit when their understanding is incomplete. No one, including the teachers, is expected to know everything. In a collaborative learning environment, people can say, “I don’t know,” and then use that acknowledgment— whether with students, parents, or teachers—as the starting point for learning. For example, when a child comes up with a question, a teacher is valued for responding, “Great question. Let’s go learn about it. I want to know the answer, too.” If the accepted approach is that “we’re all learning together,” then no one has to carry the burden of always being the expert. This is the heart of collaborative learning. Functioning as a learning community doesn’t just happen. In communicating with parents, OC teachers have to help them see that it’s okay for teachers not to know everything. The notion that “I don’t know” is a legitimate answer that forms a sound starting point for collaborative learning is a new idea for many parents.
A Historical Perspective
Authors: Kimball Bruce A.
Published: November 2020

While envisioning liberal education for the twenty-first century, we must not forget that our visions are shaped and conditioned by historical context, or tradition. Indeed, the very fact that we discuss something called "liberal education" demonstrates the influence of tradition. The general precept is well known, but the nature of this particular tradition is often misconstrued, due not only to neglect but also to genuine intentions to rescue or correct the tradition. To be sure, this particular tradition is long and complex, and it is doubtful that anyone can claim to understand fully the current situation of liberal education in light of its tradition, particularly in this era of postmodern interpretivism and deconstruction. This brief essay will therefore make two, more modest claims. First, I hope to demonstrate that, contrary to the conventional perception, the tradition of liberal education is not uniform and continuous but full of variety, discontinuity, and innovation. It has been and is a conflicted tradition. Second, I wish to argue conversely that innovative proposals made for liberal education at the end of the twentieth century often belong to the tradition, although this heritage is generally not recognized by either the proponents or their opponents. These two points, I suggest, indicate the richness and complexity of the tradition and its value, as well as its influence, for those seeking to envision what the next century of liberal education may and should hold. This is not to say that the tradition is boundless, that liberal education is all things for all situations, or that it is without blemishes or addictions, even cancerous growths. But liberal education is what we have and what we are, after centuries of trying to get it right, and we can no more wipe the slate clean and start entirely afresh here than we can in any other human endeavor. We can certainly try to change and improve in the coming century, but change and improvement imply understanding of and comparison with the past.
The Search for American Liberal Education
Authors: Wong Frank F.
Published: November 2020

When Charles William Eliot launched his radical reforms at Harvard in the late 1870s, he was convinced that the fixed curriculum, based on English liberal education models, was ill-suited to the democratic spirit, the cultural diversity, and the rapidly changing circumstances in America. By introducing the free elective system, he hoped to develop in students the habits of self-reliance that he regarded as essential to the American democratic system. Seventy years later, in a post-World War II climate of concern about the "unifying purpose and idea" for American education, Harvard issued a new version of liberal education in its famous Redbook. To address the new American circumstances, these reforms reduced rather than increased choices for students. These benchmarks of American higher education notwithstanding, the final chapter of a widely respected study by Bruce Kimball, published in 1986, opens with the observation that there is no "distinctively American view of liberal education. This observation contains an irony that raises interesting and significant questions. After such high-profile efforts as those made at Harvard, why is there no clear model of American liberal education? And if there is no such model, do we need to develop one, especially in the context of the dramatic changes affecting American society today—changes that in many ways are more radical than those faced by Charles William Eliot? Why, in this latest round of debates about the core curriculum in our colleges and universities, has the issue been posed in terms of the primacy and purity of Western civilization rather than in terms of the adequacy of our educational models to address the realities of America in the late twentieth century? These questions are even more striking when one considers the almost complete reversal of roles and the dramatic changes in orientation that have occurred in the relationship between the United States and its cultural ancestors in the Anglo-European world.
The Years before College
Authors: Gardner Howard
Published: November 2020

Participants in the past decade's discussions about precollegiate education speak informally of "waves" of educational reform. The first wave which took place in the early and middle 1980s, centered on attempts to ensure that students would secure the prerequisites for higher learning; this phase was often termed a quest for "basic skills" or the "basic literacies/' though sometimes commentators spoke more bluntly about "getting the little buggers to work harder." The second wave, which occupied the late 1980s, called for the professionalization of teachers and of building administrators. There should be a higher caliber of teachers, teachers should have more control over the events in their classrooms, and management should occur, as much as possible, directly on site. Commentators like Albert Shanker and Patricia Graham have pointed out that neither of these waves was controversial. No one could question the importance of basic skills, though the means by which they were attained, and the time by which they should be in place, merited discussion. By the same token, while some may have feared the negative consequences of too much teacher or building autonomy, it was scarcely correct politically to oppose this trend in too direct a fashion. One area of potential discussion has remained conspicuously absent from the first decade of discussions. This missing wave could be termed "the primary purpose of education." Various goals were implicit in many discussions, of course; they ranged from the preparation of a skilled workforce to the education of a wise citizenry. But there was understandable reluctance to make this discussion overt, because educators' goals are too likely to conflict with one another: the reformer who values well-roundedness or individual excellence might well clash with the reformer who values the graduate steeped in science or in the classics of Western civilization. Since reformers have needed all of the support and as much consensus as they could garner, it is not surprising that such discussions have taken place far more frequently in the corridors at meetings or in writings by individuals like Allan Bloom or E. D. Hirsch,1 who did not come from the ranks of precollegiate educators.
The Effect of Thermal Vibrations on the Intensities of the Diffracted Beams
Authors: Coppens Philip
Published: November 2020

The atoms in a crystal are vibrating with amplitudes determined by the force constants of the crystal’s normal modes. This motion can never be frozen out because of the persistence of zero-point motion, and it has important consequences for the scattering intensities. Since X-ray scattering (and, to a lesser extent, neutron scattering) is a very fast process, taking place on a time scale of 10−18 s, the photon-matter interaction time is much shorter than the period of a lattice vibration, which is of the order Thus, the recorded X-ray scattering pattern is the sum over the scattering of a large number of 1/v, or ≈10−13s. instantaneous states of the crystal. To an extremely good approximation, the scattering averaged over the instantaneous distributions is equivalent to the scattering of the time-averaged distribution of the scattering matter (Stewart and Feil 1980). The structure factor expression for coherent elastic Bragg scattering of X-rays may therefore be written in terms 〈ρ(r)〉, of the thermally averaged electron density: . . . F(H)=∫unit cell〈ρ(r)〉 exp (2πi H ·r) dr (2.1) . . . The smearing of the electron density due to thermal vibrations reduces the intensity of the diffracted beams, except in the forward |S| = 0 direction, for which all electrons scatter in phase, independent of their distribution. The reduction of the intensity of the Bragg peaks can be understood in terms of the diffraction pattern of a more diffuse electron distribution being more compact, due to the inverse relation between crystal and scattering space, discussed in chapter 1. The reduction in intensity due to thermal motion is accompanied by an increase in the incoherent elastic scattering, ensuring conservation of energy. In this respect, thermal motion is much like disorder, with the Bragg intensities representing the average distribution, and the deviations from the average appearing as a continuous, though not uniform, background, generally referred to as thermal diffuse scattering or TDS. A crystal with n atoms per unit cell has 3nN degrees of freedom, N being the number of unit cells in the crystal.
Introduction
Authors: Sperber Daniel
Published: November 2020

At the end of the introduction to my book Roman Palestine, 200-400, the Land: Crisis and Change in Agrarian Society as Reflected in Rabbinic Sources (1978), I wrote: “Finally, developments in the rural community cannot be divorced from those of the urban community. The two communities are mutually interdependent, their interactions significant for each as for both. This I hope will be shown in a future volume dealing with the conditions of urban life during the same centuries”. Some fifteen years have passed, and I have still not fulfilled that hope. This volume only satisfies my promise of a supplementary volume in a partial manner. Whereas the two former volumes, Roman Palestine, 200-400, Money and Prices (1974; 2nd edition, 1991) and the volume quoted above, presented a socioeconomic historical thesis, the present volume does not. Hence its chronological parameters have been broadened to encompass much of the Tannaitic period, and it covers a period of some three hundred years, from ca. 100 to 400 C.E. Unlike the present-day studies of ancient urban history, it does not deal with a specific city—for example, Tiberias, Sepphoris, Caesarea, or Lod—and is thus unlike the excellent studies of Lee I. Levine on Caesarea, Joshua J. Schwartz on Lod, Stuart S. Miller on Sepphoris, Gustav Hermansen on Ostia, and more recently, Donald W. Engels on Roman Corinth. My book synthesizes what is known of urban life in Talmudic Palestine and hence deals with a theoretical, nonexistent, “synthetic” city.” The reader will readily see that I have been greatly influenced by Jerome Carcopino’s seminal work on everyday life in Roman times, the classic Daily Life in Ancient Rome, which to a great extent set the tone for this genre of writing. However, he was writing about a specific town. In a sense, my narrative is closer in character to A. H. M. Jones’s paradigmatic The Greek City from Alexander to Justinian. I have also been somewhat influenced by W. A. Becker’s Gallus, or Roman Scenes of the Time of Augustus, although from a literary point of view, his work is closer to historical fiction.
Duality Theory
Authors: Floudas Christodoulos A.
Published: November 2020

Nonlinear optimization problems have two different representations, the primal problem and the dual problem. The relation between the primal and the dual problem is provided by an elegant duality theory. This chapter presents the basics of duality theory. Section 4.1 discusses the primal problem and the perturbation function. Section 4.2 presents the dual problem. Section 4.3 discusses the weak and strong duality theorems, while section 4.4 discusses the duality gap. This section presents the formulation of the primal problem, the definition and properties of the perturbation function, the definition of stable primal problem, and the existence conditions of optimal multiplier vectors.
Mixed-Integer Linear Optimization
Authors: Floudas Christodoulos A.
Published: November 2020

This chapter provides an introduction to the basic notions in Mixed-Integer Linear Optimization. Sections 5.1 and 5.2 present the motivation, formulation, and outline of methods. Section 5.3 discusses the key ideas in a branch and bound framework for mixed-integer linear programming problems. A large number of optimization models have continuous and integer variables which appear linearly, and hence separably, in the objective function and constraints. These mathematical models are denoted as Mixed-Integer Linear Programming MILP problems. In many applications of MILP models the integer variables are 0 — 1 variables (i.e., binary variables), and in this chapter we will focus on this sub-class of MILP problems. A wide range of applications can be modeled as mixed-integer linear programming MILP problems. These applications have attracted a lot of attention in the field of Operations Research and include facility location and allocation problems, scheduling problems, and fixed-charge network problems. The excellent books of Nemhauser and Wolsey (1988), and Parker and Rardin (1988) provide not only an exposition to such applications but also very thorough presentation of the theory of discrete optimization. Applications of MILP models in Chemical Engineering have also received significant attention particularly in the areas of Process Synthesis, Design, and Control. These applications include (i) the minimum number of matches in heat exchanger synthesis (Papoulias and Grossmann, 1983; see also chapter 8) (ii) heat integration of sharp distillation sequences (Andrecovich and Westerberg, 1985); (iii) multicomponent multiproduct distillation column synthesis (Floudas and Anastasiadis, 1988); (iv) multiperiod heat exchanger network, and distillation system synthesis (Floudas and Grossmann, 1986; Paules and Floudas, 1988); flexibility analysis of chemical processes (Grossmann and Floudas, 1987); (v) structural properties of control systems (Georgiou and Floudas, 1989, 1990); (vi) scheduling of batch processes (e.g., Rich and Prokapakis, 1986, 1986; Kondili et al., 1993; Shah et al, 1993; Voudouris and Grossmann, 1992, 1993); and (vii) planning and scheduling of batch processes (Shah and Pantelides, 1991, Sahinidis et al, 1989, Sahinidis and Grossmann, 1991). In addition to the above applications, MILP models are employed as subproblems in the mixed-integer nonlinear optimization approaches which we will discuss in the next chapter. In this section, we will present the formulation of Mixed-Integer Linear Programming MILP problems, discuss the complexity issues, and provide a brief overview of the solution methodologies proposed for MILP models.
The Saga of the Chicxulub Crater
Authors: Verschuur Gerrit L.
Published: November 2020

When the Alvarez team announced to the world that the K/T boundary clay contained a excess of iridium they suggested that it could only be explained if a comet or asteroid had slammed into the earth 65 million years ago. The iridium was deposited when a cloud of debris created by the vaporization of the object upon impact girdled the earth and fell back to form the so-called fireball layer. Most earth scientists were skeptical when they first heard about this. If an object 10 kilometers across had collided with enough force to trigger a global environmental catastrophe that precipitated the extinction of more than half of the species alive at the time, where was the crater? It didn’t take crater experts long to figure that the scar left by such an impact should be huge hole in the ground about 180 kilometers across and a tenth as deep. If it existed, it shouldn’t be hard to find, unless it was under the ocean somewhere, or covered in vast amounts of sediment. It turns out that when the search for the crater began there were several people, perhaps dozens, who already knew where it was. However, they either didn’t know that the search was on, or weren’t allowed to reveal what they knew. The saga of the discovery of the K/T impact crater beneath the north coast of the Yucatan Peninsula of Mexico began many decades before the discovery of iridium in the K/T boundary layer. The saga goes all the way back to 1947 when a gravity survey was started in the Yucatan by the Mexican national oil company, PEMEX. Surface gravity measurements allow geophysicists to detect the structure of rock formations deep beneath the earth’s surface. The study of gravity maps of a region then helps the scientists to figure out where oil might be found; at least that is the goal. The Yucatan survey turned up some intriguing data, including hints of a circular feature some 1,000 meters deep. In the early 1950s test wells were drilled, but no oil was found.
Solar System Debris
Authors: Verschuur Gerrit L.
Published: November 2020

The object that slammed into the earth to precipitate the dinosaur demise was no stranger to the solar system; it had been lurking about its outer regions ever since the sun and planets formed 4.5 billion years ago. Like a construction site littered with builder’s materials after the work is done, debris left over from the formation of the sun and planets is scattered throughout the solar system in the form of comets and asteroids. From among this population the great impactor that triggered the K/T extinction event originated. Unfortunately there is no way to cart the debris away so that earth won’t smash headlong into another comet or asteroid. Whether we like it or not, we live with the hazard of occasionally finding some of this stuff directly in the path of the earth’s orbit around the sun. In fact, every day something from space slams into our planet. The generic name for icy, dusty, rocky, or metallic objects that wander about in interplanetary space is “meteoroid.” After the process of planetary formation was essentially complete, a great deal of meteoroidal material was left over. Depending on its fate, a meteoroid hurtling into the earth’s atmosphere today earns a new name. It is called a meteor in the case of a tiny pea-sized particle that burns up in the atmosphere to produce a momentary fiery trail known as a shooting star. These have long been the focus of superstitions because of their obvious associations with the heavens and, therefore, with gods that might reside there. Even in our time, it is common to “make a wish upon a star” when a meteor is seen. Every night you can see dozens if not hundreds of meteor trails. On a good night in a clear location half a dozen an hour is about as good as you can expect. In addition to the meteors that burn up to leave a visible trail, there are countless that are too small to be seen, enough to allow tens of millions of wishes a day. These heat the atmosphere enough to produce trails of hot gas that reflect radar signals.
Dodging the Asteroids?
Authors: Verschuur Gerrit L.
Published: November 2020

Finding asteroids and comets that may someday slam into our planet is the first step. What do we do then? This question is being given a whole lot of attention. In early 1993 NASA and the U.S. Congress received a report of the Near-Earth-Objects Interception Workshop (Spaceguard), the first step toward creating a program for pushing aside approaching asteroids. The report stated that “There is a clear need for continuing national and international scientific investigation and political leadership to establish a successful and broadly acceptable policy.” There are two or three options open to us to avoid being wiped out. The first is to step out of the way. This may not sound very practical, and it isn’t, at least not for a planet-load of people. However, if we plan ahead we could ship a few thousand human beings to other parts of the solar system so that if the earth were to be struck, they, at least, would survive. This would only be a privilege for a few, and getting back to earth after the cataclysm could be a rather large problem in itself. Who will welcome them back upon their return? Where would they land? If we could afford to set up colonies on the moon or Mars, the colonists could wait until after the dust had settled before attempting to return. The problem with this option is that, after a really healthy thwack, the earth’s environment would be so altered that returning human beings might find this to be an alien planet. The second way in which we could avoid getting hit would be to place an object between the onrushing comet or asteroid and ourselves. For such an emergency it might pay to place a few asteroids in geocentric orbit to be maneuvered when we need them. Then we could watch the spectacle as one asteroid slams into another, possibly showering the planet with small bits of debris that might do no more than create a spectacular display of fireballs—if we get it right, of course.
The Reading-Writing Connection
Authors: Wiener Harvey S.
Published: November 2020

In 1940, the then-chairman of the editorial board of the Encyclopaedia Britannica, Mortimer J. Adler, wrote an article called "How to Mark a Book" for the Saturday Review of Literature. Adler asserted for his adult readers what must sound clearly like heresy to parents of young children. Owning a book fully, he said in absolutely timeless advice, "comes only when you have made it part of yourself, and the best way to make yourself a part of it is by writing in it." I can see you cringing. Write in this expensive, lovely book I bought Leslie at birthday time? Nothing doing. Adler pointed out that our worship of books on this level—physical objects to be revered and respected—is misguided. We love the thing, "the craft of the printer," as opposed to what it contains, "the genius of the author." Owning a book and simply placing it on the shelf means only that we have the book in our library. Truly owning a book means that we have it in our souls. Now of course we don't write in books we don't own. Books we borrow from friends or from the library or from the school classroom must stay intact for others to use later on. But your child can learn that lesson at any age—a lesson I'm sure that you try to teach regularly. Yet, you must temper your proscription. "Don't write in this book" you want to reserve for books your child does not own. "Please write in this book!" should be your plea for any volume in your youngster's home library. Why? As Adler wisely pointed out more than fifty years ago, reading a book should be a conversation between the reader and the writer. Good readers question what they find in books; they challenge what they read; and marking up a book is a way of recording the dialogue between the parties. You really do know this, don't, you, from your own days in school when you attacked review books or texts themselves or photocopies of magazine articles with much underlining, marginal comments, or highlighting.
Faraway Views : Generalizing
Authors: Wiener Harvey S.
Published: November 2020

It's been a rough Tuesday, especially in your dealings with teenagers. A mother of two young kids yourself, you expect a modicum of respect from kids ten, fifteen, or twenty years younger than you are. But today, no such luck. In Stop 'n Shop a nineteen year old stock boy packing apple sauce jars nearly knocks you over as he hoists a huge carton from a dolly to the floor. Of course, he gives you no apology. At Burger King, the order taker sneers at you when you present a fifty dollar bill; she mumbles a snide remark under her breath about your confusing a fast food store with a bank. The gas jockey at a new Exxon station gives you fifteen dollars' worth of premium when you ordered ten dollars' worth of regular and zealously begins a shouting match, demanding that you pay up because you should have been sure that he heard what you wanted. A few other similar experiences have set your teeth on edge. Kids, you grumble. Deteriorating in manners. No good, today's generation. No respect for their elders. Self-centered. Care only about their own needs and feelings. If you can remember formulating principles like these or others like them, congratulate yourself as a highorder thinker. Even though the thoughts themselves might result from unhappy experiences, you've used your good brain power to establish a broader context for your experiences. Go ahead and pat yourself on the back! What you've done is to exercise another major strategy that marks mature thought: generalizing. The ability to generalize helps you interpret your surroundings and helps you probe deeper meanings from it. It allows you to see relations between specific circumstances and more abstract conditions. Psychologists say that the process of generalizing is a process of discovery; when you see similar elements in diverse circumstances you take a conceptual leap forward in your thinking. To some, one of the primary goals of education is to create thinkers who know how to generalize.
Moms and Dads as Reading Helpers :Good Books Through The Grades
Authors: Wiener Harvey S.
Published: November 2020

Read some chilling statistics, reported in an accurate Roper Organization survey a short time ago. Pollsters telephoned a nationally representative cross section of 1,000 families with kids from three to fourteen years old. Over ninety percent of moms and dads said reading was essential to their boy or girl's success. But of those with a child who could read, only 66 percent were happy with how their youngster was reading. According to age group, these are the numbers regarding parents who thought their child was interested in reading: . . .SCHOOL LEVEL PERCENTAGE Preschool 56% Kindergarten-second grade 59% Third grade-fifth grade 53% Beyond fifth grade 39%. . . At best, therefore, according to parents, six out of ten youngsters in any of the four groups found books stimulating. Of all the families surveyed only forty-four percent said their children read for pleasure each day. The implications are astounding. Personal happiness, future education, good jobs, enlightened citizenry, the society's continued advance: these all are at stake. Looking beyond the elementary and junior high school years, a Carnegie Foundation survey of 5500 college professors revealed that 75% think undergraduates at their institutions are seriously underprepared in basic skills; 66% think their colleges are paying too much money and spending too much time teaching what students should have learned prior to college admission. The failure of our schools to develop essential skills, the pervasive indifference to books among our children, the minimal achievement level at which so many youngsters hover throughout their educational lives—these are grim barriers to knowledge, happiness, and success. We read about this new study, that commission's report, those irrefutable data. We worry for awhile and then shrug with resignation. I'm not hopeful that the depressing statistics we hear about so regularly will improve any time soon, no matter what changes we make in our country's formal educational system. But in the informal realm;—the home, the supermarket, the playground, the various child-parent intersections—fertile, untilled soil stretches out around us.
River Turtle Diversity, Adaptations, and Roles in the River Ecosystem
Authors: Moll Don , Moll Edward O.
Published: November 2020

There are river turtles and then there are turtles that live in rivers; a statement that suggests that the definition of a river turtle may not be as straightforward as it might first appear. It is an issue that must be resolved, however, in determining the scope of the treatment of the group in this book. Complications ensue from both the context in which the term “river” is applied, and from the habitat catholicity of many chelonian species. Our resolution of the first issue is to focus upon the chelonian inhabitants of larger, higher order lotic environments, and to place less emphasis on the treatment of those species that inhabit smaller streams. With a few notable exceptions (e.g., the flattened musk turtle, Sternotherus depressus due to attention by Mount, 1981; Dodd, 1988, 1990, and in press; U.S. Fish and Wildlife Service, 1990; and Bailey & Guyer, 1998), there is so little information available concerning most of these stream dwelling species that there is relatively little sacrificed with this approach. Nevertheless, we shall refer to the limited literature concerning such species when we consider it important to our treatment of river species. As river ecosystems increase in size, however, they also increase in ecological complexity and habitat diversity. While a complete analysis of these ecosystems is well beyond the scope of this book, Welcomme (1979) distinguished between two broad categories of larger rivers that provide habitat for riverine chelonians—the reservoir river and the flood plain (or flood) river. Reservoir rivers are those with generally stable flow throughout the year as a result of even annual precipitation, or the presence of marginal lakes and swamps that store water that may be slowly released into the channel throughout the year. Such rivers (e.g., the lower Zaire) overflow their banks only rarely during periods of exceptional rainfall. Many flood plain rivers have been altered to such an extent by water flow regulation due to dams, dikes, and impoundments that they now more closely resemble rivers of the reservoir type (Welcomme, 1979). The fish communities of reservoir rivers are diverse, trophically specialized, and structured into well-defined food webs (Roberts, 1973).
River Turtle Exploitation: Past and Present
Authors: Moll Don , Moll Edward O.
Published: November 2020

Turtles and their eggs have long served as an important source of food for humans—almost certainly since very early in the evolution of the hominid lineage, and surely for at least the last 20,000 years (Nicholls, 1977). Evidence in the form of shells and skeletal material (some showing burn marks as evidence of cooking) in the middens of Paleolithic aboriginal cultures, and from eyewitness accounts of explorer-naturalists in more recent times is available from numerous locations around the world (e.g., Bates, 1863; St. Cricq, 1874; Goode, 1967; Rhodin, 1992, 1995; Pritchard, 1994; Lee, 1996; Stiner et al., 1999). Skeletal evidence of river turtles, in particular from such locations as Mohenjodaro and Harappa in the Indus Valley (e.g., Indian narrow-headed softshells and river terrapins), Mayapan, and many other Mesoamerican Mayan sites (e.g., Central American river turtles), and Naga ed-Der of Upper Ancient Egypt (e.g., Nile softshell) suggest that river turtles have helped to support the rise of the world's great civilizations as well (de Treville, 1975; Nath, 1959 in Groombridge & Wright, 1982; Das, 1991; Lee, 1996). Their role continues and, in fact, has expanded as human populations have burgeoned and spread throughout the modern world. River turtles have always been too convenient and succulent a source of protein to ignore. Often large, fecund, and easily collected with simple techniques and equipment, especially in communal nesters which may concentrate at nesting sites in helpless thousands (at least formerly), river turtles are ideal prey. Much of the harvesting has been, and continues to be, conducted in relative obscurity in many parts of the world. Occasionally, however, the sheer magnitude of the resource and its slaughter has attracted the attention of literate observers, such as the early explorer-naturalists of the New and Old World tropics. Their accounts have given us some idea of the former truly spectacular abundance of some riverine species, and the equally spectacular levels of consistent exploitation which have brought them to their modern, much-diminished condition. Summaries of the exploitation of the two best documented examples of destruction of formerly abundant riverine species, the Asian river terrapin, and the giant South American river turtle, are provided under their appropriate geographic sections below.