bluuebunny/crossref_metadata_2025_split huggingface dataset:
Three-Dimensional Structure Identified from Single Sections
Authors: Elias Hans 
Published: October 2006

Errors in the identification of objects have been made frequently because of faulty interpretation of their flat images or sections. Such errors are perpetuated through a strange psychological chain reaction.
1) The first author who observes sections of an object, although presenting faithful pictures of sections of it, identifies its shape incorrectly. Such an initial mistake may be due to identification of the flat image with the object itself or to failure to consider the shape of the image as a function of the shape of the real object and the angle and level of cutting.
2) The first author describes verbally his personal concept of the object.
3) The reader reads the text of a publication before or without examining the pictorial evidence.
4) The reader's belief in the authority of the printed word immunizes him against critical evaluation of the evidence.
5) The reader regards a published opinion as a "fact."
6) A mechanism of suppression of new evidence is set up in the brain of the reader in favor of previously published, verbalized concepts. His brain unconsciously rejects new concepts that might arise intracerebrally. The printed word supersedes visual evidence.
7) A secondary mechanism parallels steps 3 to 6. An observer notices an unfamiliar figure in the microscope. Following established procedures for scientific investigations, he refrains from forming an opinion about his observation. Instead he rushes to the library searching for similar, published observations. If he finds a previous report about a similar shape, he accepts it as a "fact" and he "confirms" the previously printed viewpoint. Let me interject a personal experience concerning this mechanism. I investigated the arrangement of blood vessels in the human liver by means of corrosion preparations. The work was divided between an assistant and me. He was assigned the task of preparing drawings of two specimens. In his drawings he showed a structure which was absent from the specimens but had been described in a previous publication.
This article shows simple ways for correct initial identification of shape and structure and for the breaking of the reverberating circuit of erroneous thinking.
The Origins of Taxonomy
Authors: Raven Peter H. , Berlin Brent , Breedlove Dennis E. 
Published: October 2006

There are approximately 10 million kinds of organisms in the world, of which we have described some 15 percent. The rapid growth of the human population will cause most of the remainder to disappear from the earth before they are seen by a taxonomist. These facts suggest a more rigorous application of priorities in systematic biology as well as a careful review of the principles upon which our taxonomic system is based.
Folk taxonomies all over the world are shallow hierarchically and comprise a strictly limited number of generic taxa ranging from about 250 to 800 forms applied to plants and a similar number applied to animals. These numbers are consistent, regardless of the richness of the environment in which the particular people live. Very few specific and varietal taxa are recognized in folk taxonomic systems. Until the invention of movable type in the mid-l5th century, written taxonomies were simply records of the folk taxonomies of particular regions. Subsequently, with the possibility for the wide distribution of books, it began to seem worth while to attempt to describe and name all species of plants and animals in the world. By the year 1700, 698 genera of plants were recognized; and by the year 1778, some 1350 genera, including tens of thousands of species. In 1789 de Jussieu interpolated the family as a higher level taxonomic category in an attempt to reduce the number of important units in the system to a memorable number. The family is still the focal point in systems of angiosperm classification at present, several hundred families being recognized.
Problems with the taxonomic system stem largely from the fact that it is not designed as an information retrieval device. In folk taxonomies, names are given to organisms and these are used to communicate about the organisms with others who already know the culturally significant properties of the organisms being discussed. In dealing with the vast numbers of organisms that exist, we tend to overemphasize the process of classification and the decisions it involves at the expense of the information about the organisms that we are supposedly accumulating. Frequent changes in names exacerbate the difficulties of the system and render it still less useful for information retrieval.
With modern electronic data processing equipment, it has become possible to record information about organisms, to retain this information in a data bank, and to utilize it for various purposes, including the construction of various taxonomic systems. The invention of high-speed electronic data processing equipment is seen as analogous to but more important than the invention of movable type in the history of systematic biology. By using such equipment to its full potentialities, we should be able to achieve a qualitative improvement in our perception of the living world.
Gene Therapy for Human Genetic Disease?
Authors: Friedmann Theodore , Roblin Richard 
Published: October 2006

In our view, gene therapy may ameliorate some human genetic diseases in the future. For this reason, we believe that research directed at the development of techniques for gene therapy should continue. For the foreseeable future, however, we oppose any further attempts at gene therapy in human patients because (i) our understanding of such basic processes as gene regulation and genetic recombination in human cells is inadequate; (ii) our understanding of the details of the relation between the molecular defect and the disease state is rudimentary for essentially all genetic diseases; and (iii) we have no information on the short-range and long-term side effects of gene therapy. We therefore propose that a sustained effort be made to formulate a complete set of ethicoscientific criteria to guide the development and clinical application of gene therapy techniques. Such an endeavor could go a long way toward ensuring that gene therapy is used in humans only in those instances where it will prove beneficial, and toward preventing its misuse through premature application.
Two recent papers have provided new demonstrations of directed genetic modification of mammalian cells. Munyon et al. restored the ability to synthesize the enzyme thymidine kinase to thymidine kinase-deficient mouse cells by infection with ultraviolet-irradiated herpes simplex virus. In their experiments the DNA from herpes simplex virus, which contains a gene coding for thymidine kinase, may have formed a hereditable association with the mouse cells. Merril et al. reported that treatment of fibroblasts from patients with galactosemia with exogenous DNA caused increased activity of a missing enzyme, α-D-galactose-1-phosphate uridyltransferase. They also provided some evidence that the change persisted after subculturing the treated cells. If this latter report can be confirmed, the feasibility of directed genetic modification of human cells would be clearly demonstrated, considerably enhancing the technical prospects for gene therapy.
Classic to Postclassic in Highland Central Mexico
Authors: Dumond D. E. , Muller Florencia 
Published: October 2006

The data and argument we have presented converge on three points.
1) With the decline and abandonment of Teotihuacan by the end of the Metepec phase (Teotihuacan IV), the valleys of Mexico and of Puebla-Tlaxcala witnessed the development of a ceramic culture that was represented, on the one hand, by obvious Teotihuacan derivations in presumably ritual ware and possible Teotihuacan derivations in simpler pottery of red-on-buff, and, on the other hand, by elements that seem to represent a resurgence of Preclassic characteristics. Whether the development is explained through a measure of outside influence or as a local phenomenon, the direct derivation of a substantial portion of the complex from Classic Teotihuacan is unmistakable. This transitional horizon predated the arrival of plumbate tradeware in highland central Mexico.
2) The transitional horizon coincided with (and no doubt was an integral part of) an alteration of Classic settlement patterns so drastic that it must bespeak political disruption. Nevertheless, there is no evidence that the Postclassic center of Tula represented a significant force in the highlands at that time. There is no evidence that the center of Cholula, which may even have been substantially abandoned during the previous period, was able to exert any force at this juncture; it appears more likely that Cholula was largely reoccupied after the abandonment of Teotihuacan. There is no direct evidence of domination by Xochicalco or any other known major foreign center, although some ceramic traits suggest that relatively minor influences may have emanated from Xochicalco; unfortunately, the state of research at that center does not permit a determination at this time. Thus the most reasonable view on the basis of present evidence is that the abandonment of Teotihuacan was not the direct result of the strength of another centralized power, although some outside populations may have been involved in a minor way. Whatever the proximate cause, however, it is now clear that the abandonment of Teotihuacan led to a period of Balkanization in which no single center, or pair of centers, were dominant in the highlands.
3) The transitional horizon saw the immediate development of a cultural distinction between the Valley of Mexico and the Valley of Puebla-Tlaxcala, a distinction in which differential degrees of outside cultural influence may have played a part. This distinction was magnified in the early Postclassic, with the rising power of Tula on the west and of Cholula on the east, and Balkanization ended with the growth of empire.
Maternally Acquired Runt Disease
Authors: Beer A. E. , Billingham R. E. 
Published: October 2006

Without altering the structural integrity of the placenta by irradiation or drugs, we have shown that it is possible to immunize females both adoptively and actively against the paternally inherited transplantation antigens of their fetuses. Such immunization causes a high incidence of runt disease among the litters. Although the putative chimeric status of the affected offspring has yet to be confirmed, the results of our experiments support the thesis that runt disease is caused by the activities of "unwanted" immigrant lymphocytes from the maternal circulation. Our results suggest that immunologically activated cells are more likely to cross the placenta than normal cells and that this greater mobility may not be related to the immunologic specificity of the activated cells.
Two factors may have contributed to the apparent failure of numerous previous attempts to demonstrate the capacity of transplantation immunity to affect the well-being of a fetus or, more correctly, its placenta, in the way that might be expected of a homograft. (i) Investigators were preoccupied with obtaining a classic type of rejection, in utero, analogous to the rejection of an orthotopic skin homograft. The birth of consistently healthy-looking litters, interpreted as a failure of the experiment, convinced the investigators of the efficacy of nature's solution of the homograft problem and there was no reason for them to suspect its possible limitations. Observation of the litters for several weeks might have uncovered the phenomenon of maternally induced runt disease. (ii) Most investigators resorted to hyperimmunization of the mothers. This would have facilitated the synthesis of protective isoantibodies capable of interfering with the expression of the potentially harmful cellular immune response.
Ever since the abnormalities of runt disease were first described they have repeatedly been compared to those observed in patients with certain lymphomas. Various theories have been propounded as to how maternally transmitted graft-versus-host reactivity might lead to the development of these tumors. In mice it has been established that graft-versus-host reactivity may result in a high incidence of lymphomas . Recent analysis indicates that this graft-versus-host reactivity unmasks and activates normally latent and undemonstrable oncogenic viruses. The work we describe in this article may have some relevance to the possible clinical significance of transplacental cellular mobility in man. We suggest that the relatively high incidence of lymphomas in children might also be, in part at least, due to unmasking of oncogenic viruses by subclinical graft-versus-host reactivity mediated by immunocompetent cells of maternal origin. The statistical evidence that male infants are at greater risk than females is concordant with our observation that maternally induced runts include a significantly higher proportion of males than females.
Feedback: Beyond Behaviorism
Authors: Powers William T. 
Published: October 2006

Consistent behavior patterns are created by variable acts, and generally repeat only because detailed acts change. The accepted explanation of this paradox, that "cues" cause the changes, is irrelevant; it is unsupported by evidence, and incapable of dealing with novel situations.
The apparent purposefulness of variations of behavioral acts can be accepted as fact in the framework of a control-system model of behavior. A control system, properly organized for its environment, will produce whatever output is required in order to achieve a constant sensed result, even in the presence of unpredictable disturbances. A control-system model of the brain provides a physical explanation for the existence of goals or purposes, and shows that behavior is the control of input, not output.
A systematic investigation of controlled quantities can reveal an organism's structure of control systems. The structure is hierarchical, in that some quantities are controlled as the means for controlling higher-order quantities. The output of a higher-order system is not a muscle force, but a reference level (variable) for a lower-order controlled quantity. The highest-order reference levels are inherited and are associated with the meta-behavior termed reorganization.
When controlled quantities are discovered, the related stimulus-response laws become trivially predictable. Variability of behavior all but disappears once controlled quantities are known. Behavior itself is seen in terms of this model to be self-determined in a specific and highly significant sense that calls into serious doubt the ultimate feasibility of operant conditioning of human beings by other human beings.
Hydrological and Ecological Problems of Karst Regions
Authors: LeGrand H. E. 
Published: October 2006

Climate exerts a universal dominant influence on ecology, but processes of karstification have an equally high ecological influence in carbonate rock regions. Development of karst features depends greatly on the degree to which water containing carbon dioxide has been able to move on and through carbonate rocks and to remove some of the rock in solution. Distinctive features of many karst terranes include scarcity of soils, scarcity of surface streams, and rugged topography; less distinctive are the highly permeable and cavernous rocks, especially at the shallow depths. This high permeability gives rise to many practical problems, including (i) scarcity and poor predictability of groundwater supplies, (ii) scarcity of surface streams, (iii) instability of the ground, (iv) leakage of surface reservoirs, and (v) an unreliable waste-disposal environment.
Natural karst processes in some carbonate rock regions have caused a greater restriction in the development of biota than man can ever be suspected of causing.
Electrotonic Processing of Information by Brain Cells
Authors: Schmitt Francis O. , Dev Parvati , Smith Barry H. 
Published: October 2006

In contrast to well-studied through-projection neurons that propagate information from one region to another in the central nervous system, short-axon or axonless neurons form local circuits, transmitting signals through synapses and electrical junctions between their dendrites. Interaction in this dendritic network proceeds without spike action potentials. Interaction is mediated by graded electrotonic changes of potential and is transmitted through high sensitivity (submillivolt threshold) synapses rather than by the lower sensitivity (20 to 100-mv threshold) synapses typical of projection neurons. A crucial feature of local circuits is their high degree of interaction both through specialized junctional structures and through the extracellular fields generated by local and more distant brain regions.
The anatomical evidence for the nature and distribution of neuronal local circuits in the nervous system is surveyed. Bioelectric mechanisms are discussed in relation to the special properties of local circuits, including dendrodendritic synapses, synaptic sensitivity, electrotonic coupling, and field effects. Intraneuronal and interneuronal transport of various types of substances suggests that the biochemical and the bioelectrical parameters are functionally interwoven. Through such interactions neuronal local circuits, with their distinctive properties, may play an essential role in higher brain function.
The Lunar Laser Ranging Experiment
Authors: Bender P. L. , Currie D. G. , Poultney S. K. , Alley C. O. , Dicke R. H. , Wilkinson D. T. , Eckhardt D. H. , Faller J. E. , Kaula W. M. , Mulholland J. D. , Plotkin H. H. , Silverberg E. C. , Williams J. G. 
Published: October 2006

The lunar ranging measurements now being made at the McDonald Observatory have an accuracy of 1 nsec in round-trip travel time. This corresponds to 15 cm in the one-way distance. The use of lasers with pulse-lengths of less than 1 nsec is expected to give an accuracy of 2 to 3 cm in the next few years. A new station is under construction in Hawaii, and additional stations in other countries are either in operation or under development. It is hoped that these stations will form the basis for a worldwide network to determine polar motion and earth rotation on a regular basis, and will assist in providing information about movement of the tectonic plates making up the earth's surface. Several mobile lunar ranging stations with telescopes having diameters of 1.0 m or less could, in the future, greatly extend the information obtainable about motions within and between the tectonic plates.
The data obtained so far by the McDonald Observatory have been used to generate a new lunar ephemeris based on direct numerical integration of the equations of motion for the moon and planets. With this ephemeris, the range to the three Apollo retroreflectors can be fit to an accuracy of 5 m by adjusting the differences in moments of inertia of the moon about its principal axes, the selenocentric coordinates of the reflectors, and the McDonald longitude. The accuracy of fitting the results is limited currently by errors of the order of an arc second in the angular orientation of the moon, as derived from the best available theory of how the moon rotates in response to the torques acting on it. Both a new calculation of the moon's orientation as a function of time based on direct numerical integration of the torque equations and a new analytic theory of the moon's orientation are expected to be available soon, and to improve considerably the accuracy of fitting the data.
The accuracy already achieved routinely in lunar laser ranging represents a hundredfold improvement over any previously available knowledge of the distance to points on the lunar surface. Already, extremely complex structure has been observed in the lunar rotation and significant improvement has been achieved in our knowledge of lunar orbit. The selenocentric coordinates of the retroreflectors give improved reference points for use in lunar mapping, and new information on the lunar mass distribution has been obtained. Beyond the applications discussed in this article, however, the history of science shows many cases of previously unknown phenomena discovered as a consequence of major improvements in the accuracy of measurements. It will be interesting to see whether this once again proves the case as we acquire an extended series of lunar distance observations with decimetric and then centimetric accuracy.
Resource Partitioning in Ecological Communities
Authors: Schoener Thomas W. 
Published: October 2006

To understand resource partitioning, essentially a community phenomenon, we require a holistic theory that draws upon models at the individual and population level. Yet some investigators are still content mainly to document differences between species, a procedure of only limited interest. Therefore, it may be useful to conclude with a list of questions appropriate for studies of resource partitioning, questions this article has related to the theory in a preliminary way.
1) What is the mechanism of competition? What is the relative importance of predation? Are differences likely to be caused by pressures toward reproductive isolation?
2) Are niches (utilizations) regularly spaced along a single dimension?
3) How many dimensions are important, and is there a tendency for more dimensions to be added as species number increases?
4) Is dimensional separation complementary?
5) Which dimensions are utilized, how do they rank in importance, and why? How do particular dimensions change in rank as species number increases?
6) What is the relation of dimensional separation to difference in phenotypic indicators? To what extent does the functional relation of phenotype to resource characteristics constrain partitioning?
7) What is the distance between mean position of niches, what is the niche standard deviation, and what is the ratio of the two? What is the niche shape?
The Surface of the Ice-Age Earth
Authors:   CLIMAP Project Members
Published: October 2006

In the Northern Hemisphere the 18,000 B.P. world differed strikingly from the present in the huge land-based ice sheets, reaching approximately 3 km in thickness, and in a dramatic increase in the extent of pack ice and marine-based ice sheets. In the Southern Hemisphere the most striking contrast was the greater extent of sea ice. On land, grasslands, steppes, and deserts spread at the expense of forests. This change in vegetation, together with extensive areas of permanent ice and sandy outwash plains, caused an increase in global surface albedo over modern values. Sea level was lower by at least 85 m.
The 18,000 B.P. oceans were characterized by: (i) marked steepening of thermal gradients along polar frontal systems, particularly in the North Atlantic and Antarctic; (ii) an equatorward displacement of polar frontal systems; (iii) general cooling of most surface waters, with a global average of –2.3°C; (iv) increased cooling and up-welling along equatorial divergences in the Pacific and Atlantic; (v) low temperatures extending equatorward along the western coast of Africa, Australia, and South America, indicating increased upwelling and advection of cool waters; and (vi) nearly stable positions and temperatures of the central gyres in the subtropical Atlantic, Pacific, and Indian oceans.