bluuebunny/crossref_metadata_2025_split huggingface dataset:
Induction of c‐fos mRNA Expression in Rat Striatum by Neuroleptic Drugs
Authors: Miller Jeannette C. 
Published: October 2006

Abstract:The effect of selective dopamine D2 receptor‐acting drugs on striatal c‐fos mRNA expression in the rat has been investigated by Northern hybridization and autoradiography to determine a possible role for c‐fos in the initiation of adaptive changes in D2 receptor number by neuroleptic drugs. The neuroleptic drug haloperidol, a D2 receptor antagonist, was found to produce a rapid and transient induction of c‐fos mRNA expression as compared with the expression in animals treated with saline. This induction by haloperidol was found to be dose dependent and D2 receptor mediated, inasmuch as a D2 agonist completely reversed the induction and the inactive isomer of the neuroleptic butaclamol, which does not produce an increase in D2 receptors, had no effect on c‐fos mRNA expression. From these data, it can be concluded that c‐fos expression in striatum is under dopamine D2 receptor‐mediated inhibitory control. It is suggested that c‐fos may play a role in the initiation of the increase in D2 receptor number produced by chronic neuroleptic drug treatment.
Stereospecific Polymerization
Authors: Ketley A. D. , Werber F. X. 
Published: October 2006

The great flurry of activity which followed the announcement of Ziegler and Natta's initial results has led to the discovery of an enormous number of catalyst systems which are effective in stereospecific polymerization. However, there is little more understanding now than in 1955 of how most of these systems work. Now that the initial excitement has cooled, a larger amount of thoughtful work on the mechanisms of these reactions should appear. As a basis for understanding both the heterogeneous and homogeneous systems, more mechanism studies in organometallic chemistry are urgently needed. More specifically for the heterogeneous catalysts, continued attempts should be made to find better models for the active sites, and new analytical methods should be sought to provide more information concerning the active site itself. In homogeneous systems, greater understanding of the ion pairs, the structure of which is so critical, could be obtained by the preparation and study of nonpolymeric analogues.
In addition to understanding better the catalysts that we already have, we may see in the future the development of new kinds of catalysts. Some of these may be capable of producing polymers in which the units have a more complex code than in those produced by simple stereospecific catalysts. Such catalysts already exist in nature. For example, we now know that the RNA molecule functions as a multifunctional catalyst in peptide syntheses, each sequence of three bases along the backbone corresponding to a particular amino acid. The molecule consequently acts as a catalytic template which defines the order in which these amino acids polymerize into the final peptide. Synthetic RNA's have also been prepared containing only one base such as uracil along the chain.
Since three uracil units correspond to phenylalanine, the polyuracil acts as a template for the formation of a peptide containing only this amino acid. There seems no reason why, ultimately, we should not be able to synthesize polymeric catalysts of this type which can act as templates for the polymerization of specific monomers other than those found in living systems. If a number of systems such as this can be found, we will be on the road to producing catalysts which can not only control the stereochemistry of a polymer chain but also the order in which a group of different monomers can enter into it.
Milk Production of Cows on Protein-Free Feed
Authors: Virtanen Artturi I. 
Published: October 2006

The synthesis of bacterial protein in the rumen of lactating cows fed on purified carbohydrates, with urea and ammonium salts as the sole sources of nitrogen, can be increased, through feed adaptation, to a level adequate not only for the maintenance of the cow but also for a relatively high milk production. The best annual milk yield per cow on the experimental feed has, so far, been 4217 kilograms, calculated as standard milk (684 kilocalories per kilogram of milk). The composition of the test milk is similar to that of normal fat- and protein-rich milk. Fractionation of casein and serum proteins of test milk and normal milk by different methods demonstrated the similarity of the proteins of the two milks. The normal or higher concentrations of the water-soluble vitamins in test milk show that the biosynthesis of these vitamins in the rumen is vigorous. The flavor of the two milks is very similar—proof that biosynthesis of the effective flavor compounds of milk occurs in the body of the cow. The only component of test milk whose composition, when small amounts of vegetable oil have been fed, has differed from that of normal milk is the fat.
The studies of milk production on the experimental feed have opened up new possibilities for investigating the biosynthesis of different milk components. The studies are also of practical importance: Since the vigorous biosynthesis of proteins from simple nitrogen compounds in the rumen of test-feed-adapted cows has been demonstrated, there are greater possibilities for studying the replacement of protein by urea. In countries where there are plenty of forests, part of the feed of cows can be made up of certain wood products—for instance, hemicellulose and cellulose of low quality. The new findings may also be of value in the dry areas of the globe, where milk would be of vital significance for improving the nutrition of the population.
Death in Embryonic Systems
Authors: Saunders John W. 
Published: October 2006

The principal conclusion to be drawn from the foregoing discussion is that the death of cells and the destruction of tissues, organs, and organ systems are programmed as normal morphogenetic events in the development of multicellular organisms. Death in embryonic systems may thus be explored within the same conceptual framework as growth and differentiation.
The present exploration has revealed that death during embryogenesis serves utilitarian goals in some instances, at least, that its occurrence is subject to control by factors of the immediate cellular and humoral environment, and that aberrations in its normal pattern of expression provide the mechanism for realization of many mutant phenotypes. Hopefully, it has also pointed toward the appropriate formulation of some of the problems that confront us in understanding the control of death at the level of genetic transcription, the biochemical events which determine and accompany its occurrence, and the pathways of disposition and the developmental significance of disassembled cellular building blocks.
Auditory System of Noctuid Moths
Authors: Roeder Kenneth D. 
Published: October 2006

Insect-eating bats find their aerial food by sonar, through emitting ultrasonic chirps and locating sources of echoes. Certain moths have ears sensitive to these chirps and can detect bats well beyond the range of the bats' sonar. On hearing a distant bat, many moths turn and fly directly away from the source of ultrasound. Only one sense cell in each ear of a moth provides the primary nervous information for this response. This article describes my initial attempts to find out how a moth's central nervous system processes the train of chirps reaching its two ears.
The ear of a restrained moth is exposed to a sequence of artificially generated ultrasonic pulses that approximates the cries made by a bat. This stimulus can be varied with respect to ultrasonic frequency (pitch), pulse intensity, pulse duration, the interval between pulses, and pulse-train duration.
The more sensitive acoustic sense cell responds to all frequencies between about 15,000 and 80,000 cycles per second, but the signal that it transmits to the moth's central nervous system contains no measure of frequency within this range. However, this nerve signal reports variations in the other parameters of the stimulus. The acoustic fiber connects, in the central nervous system, with various nerve cells that transform the signal farther. The signal from a pulse-marker neuron contains no measures of pulse intensity or pulse duration, reporting only changes in interpulse interval and pulse-train duration. A train-marker neuron reports only the duration of the pulse train. The stimulus parameters may be likened to keys, each of which is necessary to gain admittance through a given door but becomes superfluous once this door has been passed. This analogy suggests one of the ways in which a signal is transformed in its passage through the nervous system, and how its specificity is assured in eliciting a given response.
In addition to undergoing this kind of transformation, neural signals generated in the two directionally sensitive ears must be combined if a flying moth is to steer a course away from a distant bat. Neurons have been discovered in the central ganglia which summate signals from the right and left ears. Other neurons are inhibited in their activity by stimulation of one ear. The moth may combine signals from these neurons with motor-nerve information on the attitude of its own wings, which act as oscillating baffles modifying its directional acoustic sensitivity 20 to 40 times a second as it flaps an erratic path through the darkness.
A Theory of Self-Nonself Discrimination
Authors: Bretscher Peter , Cohn Melvin 
Published: October 2006

1) Induction of humoral antibody formation involves the obligatory recognition of two determinants on an antigen, one by the receptor antibody of the antigen-sensitive cell and the other by carrier antibody (associative interaction).
2) Paralysis of antibody formation involves the obligatory recognition of only one determinant by the receptor antibody of the antigen-sensitive cell; that is, a nonimmunogenic molecule (a hapten) can paralyze antigen-sensitive cells.
3) There is competition between paralysis and induction at the level of the antigen-sensitive cell.
4) The mechanisms of low- and high-zone paralysis, and maintenance of the unresponsive state, are identical.
5) High-zone paralysis occurs when both the carrier antibody and the receptor antibody are saturated, so that associated interactions cannot take place.
6) The mechanisms of paralysis and induction for the carrier-antigen-sensitive cell are identical to those for the humoral-antigen-sensitive cell.
7) The formation of carrier-antigen-sensitive cells is thymus-dependent, whereas humoral-antigen-sensitive cells are derived from bone marrow. Since carrier antibody is required for induction, all antigens are thymus-dependent.
8) The interaction of antigen with the receptor antibody on an antigen-sensitive cell results in a conformational change in an invariant region of the receptor and consequently paralyzes the cell. As the receptor is probably identical to the induced antibody, all antibody molecules are expected to be able to undergo a conformational change on binding a hapten. The obligatory associated recognition by way of carrier antibody (inductive signal) involves a conformational change in the carrier antibody, leading to a second signal to the antigen-sensitive cell.
9) The foregoing requirements provide an explanation for self-nonself discrimination. Tolerance to self-antigens involves a specific deletion in the activity of both the humoral- and the carrier-antigen-sensitive cells.
Participatory Technology
Authors: Carroll James D. 
Published: October 2006

The hunger to participate that exists today in various segments of the American public is in part a response to what some people perceive as an unresponsiveness of institutions and processes to the felt needs of the individual and of society. It is also, in part, an expression of a desire for a redistribution of power in American public life.Technology is one of the major determinants of the nature of public as well as private life in contemporary society. Participatory technology is an attempt on the part of diverse individuals and groups to influence technological processes through participation in existing or new public processes by which technology is or can be developed, controlled, and implemented. Like other processes of direct citizen participation in governmental decision making, it raises many questions about the adequacy of existing theories and practices of representative government. These questions cannot be answered on an a priori basis. Members of the educational, scientific, technical, and governmental communities should analyze these questions in an effort to develop answers that are appropriate to the particular situations for which they are responsible and with which they are concerned.
Radio Stars
Authors: Hjellming R. M. , Wade C. M. 
Published: October 2006

Up to the present time six classes of radio stars have been established. The signals are almost always very faint and drastically variable. Hence their discovery has owed as much to serendipity as to the highly sophisticated equipment and techniques that have been used. When the variations are regular, as with the pulsars, this characteristic can be exploited very successfully in the search for new objects as well as in the detailed study of those that are already known. The detection of the most erratically variable radio stars, the flare stars and the x-ray stars, is primarily a matter of luck and patience. In the case of the novas, one at least knows where and roughly when to look for radio emission.
A very sensitive interferometer is clearly the best instrument to use in the initial detection of a radio star. The fact that weak background sources are frequently present makes it essential to prove that the position of a radio source agrees with that of a star to within a few arc seconds. The potential of radio astronomy for the study of radio stars will not be realized until more powerful instruments than those that are available today can be utilized. So far, we have been able to see only the most luminous of the radio stars.
Food Production and the Energy Crisis
Authors: Pimentel David , Hurd L. E. , Bellotti A. C. , Forster M. J. , Oka I. N. , Sholes O. D. , Whitman R. J. 
Published: October 2006

The principal raw material of modern U.S. agriculture is fossil fuel, whereas the labor input is relatively small (about 9 hours per crop acre). As agriculture is dependent upon fossil energy, crop production costs will also soar when fuel costs increase two- to fivefold. A return of 2.8 kcal of corn per 1 kcal of fuel input may then be uneconomical.
Green revolution agriculture also uses high energy crop production technology, especially with respect to fertilizers and pesticides. While one may not doubt the sincerity of the U.S. effort to share its agricultural technology so that the rest of the world can live and eat as it does, one must be realistic about the resources available to accomplish this mission. In the United States we are currently using an equivalent of 80 gallons of gasoline to produce an acre of corn. With fuel shortages and high prices to come, we wonder if many developing nations will be able to afford the technology of U.S. agriculture.
Problems have already occurred with green revolution crops, particularly problems related to pests. More critical problems are expected when there is a world energy crisis. A careful assessment should be made of the benefits, costs, and risks of high energy-demand green revolution agriculture in order to be certain that this program will not aggravate the already serious world food situation.
To reduce energy inputs, green revolution and U.S. agriculture might employ such alternatives as rotations and green manures to reduce the high energy demand of chemical fertilizers and pesticides. U.S. agriculture might also reduce energy expenditures by substituting some manpower currently displaced by mechanization.
While no one knows for certain what changes will have to be made, we can be sure that when conventional energy resources become scarce and expensive, the impact on agriculture as an industry and a way of life will be significant. This analysis is but a preliminary investigation of a significant agricultural problem that deserves careful attention and greater study before the energy situation becomes more critical.
The Economics of Resource Recovery from Municipal Solid Waste
Authors: Abert James G. , Alter Harvey , Bernheisel J. Frank 
Published: October 2006

A prototypical operating statement similar to that used by business firms has been shown to be a useful decision-making tool for a community choosing a solid waste management system. When applied to resource recovery, it highlights the economics of recovery and the values of the input parameters necessary to achieve economic viability, whether in the case of public or private ownership.
In most communities, refuse processing to recover material resources must be based on more than one source of revenue. In addition to the revenues from the sale of by-products, there must be revenues from processing the incoming refuse and from a user, or dump, fee. In the first case discussed, that of materials recovery by a front end system, resource recovery is shown to be economically feasible for those communities in which the present cost of disposal is relatively high. The indifferent community was one having a current cost of $7.72 per ton; more accurately, this would be the cost for the near-term future. It is not necessary that current costs be used, since many communities are merely "dumping" their refuse. The indifference decision should be based on the cost of an environmentally sound alternative.
Energy recovery from municipal solid waste can increase the number of communities in which resource recovery will be an economic adjunct to a solid waste management system. The analysis presented here was based on the assumption that the value of the fuel recovered exactly offset the additional capital and operating costs of the utility which burns it. There could be costs above and beyond this; similarly, there could be a saving by taking into account the economic value of the organic fraction as fuel. However, it is believed that the assumption under which the materials-plus-energy case was analyzed seems to be realistic at this time.
Mineral Resources, Economic Growth, and World Population
Authors: Brooks David B. , Andrews P. W. 
Published: October 2006

World population and world income can grow at any likely rate for the next 50 to 75 years, probably for longer, and mineral supplies will continue to keep pace with demand. Not, however, without environmental costs, without affecting Third World development, and, perhaps most important, without ignoring critical questions of power. In what might be termed the revisionist form of the limits to growth thesis, Aurelio Peccei and Alexander King, cofounders of the Club of Rome, seem to be saying that the forecasts of doom themselves are unimportant but they symbolize critical problems of the nature and uses of power in the modern world:
. . . the Club of Rome is questioning the quality of growth and its distribution around the world. . . . We know that the present structure of the world is obsolete. . . . Both private and state capitalism are stale . . . we have to develop something else.
Surely, continually increasing rates of mineral production are symptoms of this obsolete power structure, a result of the fact that, ultimately, population growth and monetary income growth lead to demands for natural resources that necessitate their being found and produced regardless of the implications. Since such higher rates of production are geologically and economically sustainable, we should choose among alternative paths of growth, and hence among alternative rates of mineral resource development, according to what we like or dislike about these implications. The key information will not be found in tables comparing reserves and consumption but in preferences and ethics.
Rural Health Care in Mexico?
Authors: Caedo Luis 
Published: October 2006

A very large percentage of Mexico's population living in rural areas lacks resources for health care. Any new effort to provide such care must emphasize the health of the infant population because of the high percentage of infants in the country. Plans made at the national level have not been correlated with the conditions that exist in rural areas. For example, the majority of university programs are oriented toward urban medical practice, and the construction of more schools of medicine to solve the problem of doctors in rural areas is based on a mistaken premise. This problem has not been solved even in developed countries such as the United States where, as in Mexico, graduates in medicine migrate to the cities where optimal conditions are met for practicing the type of medicine for which they have been trained. Furthermore, it is both expensive and illogical to maintain urban doctors in rural areas where they cannot practice their profession for lack of resources; to do so is to deny the purpose of their education. Conventional schools of medicine, for reasons of investment and of structure, should teach only very selected groups of students who, on finishing their training, are fully capacitated to practice specialized medicine. A different system is required if we are to provide adequate health care in the rural communities. A system such as that described herein, adapted to the real need of rural communities, would avoid the necessity to create dysfunctional bureaucracies and would not destroy those institutions which have proved useful in the past. This study should be considered as one of the many pilot programs that should be initiated in order to determine the type of program that would best solve the problem of health care in rural Mexico. Other programs already being considered at the National Autonomous University of Mexico include the A36 plan of the Faculty of Medicine, now in operation; the work of C. Biro carried out in Netzahualcoyotl City (both focused on providing medical care to the urban poor); and the Open University program.
Unless an efficient program designed to meet the needs of rural communities is quickly put into operation, Mexico will, in the near future, be facing the same problems now confronting Southeast Asia.