Showing papers by "Rutgers University published in 1969"

The Adjustment of Stock Prices to New Information

Abstract: There is an impressive body of empirical evidence which indicates that successive price changes in individual common stocks are very nearly independent. Recent papers by Mandelbrot and Samuelson show rigorously that independence of successive price changes is consistent with an "efficient" market, i.e., a market that adjusts rapidly to new information. It is important to note, however, that in the empirical work to date the usual procedure has been to infer market efficiency from the observed independence of successive price changes. There has been very little actual testing of the speed of adjustment of prices to specijc kinds of new information. The prime concern of this paper is to examine the process by which common stock prices adjust to the information (if any) that is implicit in a stock split

Factor stimulating transcription by RNA polymerase.

Abstract: A protein component usually associated with RNA polymerase can be separated from the enzyme by chromatography on phosphocellulose. The polymerase is unable to transcribe T4 DNA unless this factor is added back.

Does Violence Breed Violence? Contributions from a Study of the Child Abuse Syndrome

Abstract: A study covering three generations of families of abused children supports the themes that violence breeds violence and that a child who experiences violence as a child has the potential of becoming a violent member of society in the future. The authors believe that the physician has a critical role and responsibility in interrupting this cycle of violence.

E. coli sigma factor: a positive control element in phage T4 development.

Abstract: The σ factor of E. coli RNA polymerase selectively promotes transcription of T4 phage pre-early genes. The residual activity of the minimal enzyme on T4 DNA is caused by random initiation on both strands of the entire T4 DNA molecule.

The development of maternal responsiveness in the rat

Abstract: Maternal responsiveness in the rat develops gradually during pregnancy and parturition, and in the postpartum period of maternal care. Virgins can be shown to have a basic level of maternal responsiveness, which is raised during pregnancy and again at parturition. After parturition the young maintain the mother's maternal responsiveness, but there are indications that as they grow older they cause a decline in her responsiveness. Maternal responsiveness is shown to be based upon substance(s) carried in the blood of the postparturient mother. Transferring blood plasma from a new mother to a virgin causes the latter to become maternal towards young within 48 hours, where normally it requires two to three times this period of exposure to young.

Intervention as a scientific concept

Abstract: The deeper one delves into the literature on intervention, the more incredulous one becomes. The discrepancy between the importance attached to the problem of intervention and the bases on which solutions to it are founded is so striking that at first one wonders whether an adequate sample of the literature has been examined. Enlargement of the sample, however, only makes the discrepancy more glaring, and after pursuing every footnote that suggests a different approach and ruminating in a wide variety of documents, one is compelled to conclude that the literature is indeed incredible. The spirit of scientific explanation appears to have had no impact on it whatsoever. In an age when it is second nature to assume that the solution of problems requires comprehension of their sources, scholarly writings on the problem of intervention are singularly devoid of efforts to develop systematic knowledge on the conditions under which interventionary

Microbial Decomposition of Methionine and Identity of the Resulting Sulfur Products

Abstract: Various bacteria, actinomycetes, and filamentous fungi decomposed methionine, but only certain aerobic bacteria isolated from soil decomposed it in the absence of other organic substrates. These bacteria could grow on methionine as the only organic substrate and source of nitrogen and sulfur. Methionine was first deaminated and then demethiolated with production of methanethiol, part of which was oxidized to dimethyl disulfide. The amount of methanethiol that was oxidized varied with different cultures. A bacterial culture initially unable to grow on methionine developed capacity to do this in a medium which contained methionine and other growth substrates. The two sulfur products, methanethiol and dimethyl disulfide, are volatile and escaped from the media, resulting in a decrease in the sulfur content proportional to the amount of methionine decomposed.

Near-optimum design of linear systems by a singular perturbation method

Abstract: It is shown that the state feedback matrix of a linear system optimal with respect to a quadratic performance index can be expanded in a MacLaurin series in parameters which change the order of the system. The first two terms of this series are employed in a near-optimum design for a high-order plant. The result of the near-optimum design is superior to that achieved by a conventional low-order design, while the amount of computation is considerably less than that required for a high-order design. An example of a second-order design for a fifth-order plant is given.

Body weight loss as a measure of motivation in hunger and thirst

Abstract: An animal deprived of food or water does two things: He loses weight and he becomes more active. Many studies have shown an intimate relation between these two classes of events (cf. Bolles, 1967). The premise of this paper is that further study of this relation may add to the knowledge of the underlying physiological substrates of hunger and thirst. Three hypotheses are examined: ( 1 ) Body weight loss as an active process involved in the defense of certain physiological parameters and, therefore, a basic measure of degree of depletion; (2) Body weight loss as a basic measure of motivation, as reflected in levels of instrumental or spontaneous activity; and (3) Depletion as related to motivation via the recovery growth function. The first question to be examined is how body weight (BW) is lost under conditions of restricted food or water intake. Both within and among species there is, in general, a linear relation between the log intake of water or food and log BW (Adolph, 1949; Kleiber, 1961; Richter & Brailey, 1929). In a fasting animal the same relation holds between his final (asymptotic) weight and the size of ration given. This suggests that for any given nutrient, the amount of the nutrient consumed is always proportional to the resulting BW, thus maintaining a constant ratio. If the nutrient is present in inadequate amounts, and none of the nutrientprocurring or -conserving responses of the animal is sufficient, it follows that BW must be lost in order to conserve the ratio of the nutrient consumed to BW. First, let us consider the case of water deprivation. The hypothesis is that the ratio of body water to lean body mass must be maintained (Collier, 1964; Collier 8~ Knarr, 1966; Collier & Levitsky, 1967). FIGURE 1 presents the weight-loss curves for two groups of rats. The animals represented by the upper curve rereceived 24 percent of their ad lib intake of water, whereas the lower curve animals received no water. TABLE 1 shows the percentage of water, determined by drying, in a selected set of organs from animals sacrificed at various times following the institution of the 24-percent ration. No significant differences as a function of time were observed. Similar results were obtained for the second group receiving no water (see also Wolf, 1958). Upon further examination of the curves in FIGURE 1, several questions arise: How is the rat losing weight, and what is the end point of the weight loss? Does BW stabilize on a limited ration and if so, at what value? Kleiber (1961 ) suggests that a fasting animal consumes himself at a rate proportional to the amount of active metabolic tissue left at any moment. If metabolic rate does not change greatlv during fasting, as suggested by Rixson and Stevenson (1957), one may predict from this assumption that log BW will decline linearly as a function of time (cf bottom curve of FIGURE I ). When some water or food is available, the rate of decline decreases as the BW approaches a value that can be supported by the amount of nutrient given. FIGURE 2 shows this relation between asymptotic weight and water ration for groups of rats given different proportions of their ad lib water intake. The form of this curve is the classic linear function relating log of food or water intake and log BW in ad lib-fed ani-

Amphotericin B and other polyenic antifungal antibiotics.

Abstract: The polyenic antifungal antibiotics are a large group of related macrolides whose ring contains a rigid planar lipophilic portion and a flexible hydrophilic portion. These inhibit growth of fungi (but not of bacteria) and have significant value in treatment of intestinal or topical monilial infections. Amphotericin B is used systemically for the treatment of acute histoplasmosis and blastomycosis. After the initial demonstration of therapeutic utility, attention became focused on the in vitro biologic action of the polyenes. The critical step was identified as formation of a complex with the membrane sterol of sensitive organisms. The consequences of this binding are being examined using natural and artificial membranes. The surprising feature that has emerged is the wide variation in ultimate physiologic effects produced by the individual polyenes. Investigation of this problem should provide important information on membrane function as well as on the nature of the specific membrane complexes. Finally, and of great interest at the moment, physiologic and pharmacologic effects on sterol and steroid metabolism in animals have been observed. These changes are consistent with available information on the mechanism of the microbial action of the polyenes. The possible practical application of these discoveries is of great interest.

Laughing gull chicks: recognition of their parents' voices.

Abstract: Laughing gull chicks between 6 and 13 days old responded to the calls of their own parents with orientation toward the sound, approach, increased locomotion, and vocalization. In response to the same kinds of calls from other adults they tended to orient away from the sound, withdraw, and sit or crouch. Chicks as young as 6 days can identify their parents from individual characteristics in the calls of adult gulls.

Gregarious Setting in the American Oyster Crassostrea virginica Gmelin

Abstract: In laboratory cultures of setting oyster larvae,Crassostrea virginica, it was noted that few of many exposed cultch shells collected most of the set. Also, setting, was very sporadic with respect to time. Several hypotheses were tested to explain such observations. Individual cultch shells were not differentially attractive to setting larvae. However, cultch shells containing 24-hour-old spat or 2-month-old spat attracted more set than unspatted control shells in the same culture and stimulated more set than that received in separate control cultures. Undersides of bottom-most layers of shells attracted more set than the higher layers of shells in laboratory cultures. Two-month-old spat, inside larval-proof plankton mesh bags, stimulated set on shells outside the bags indicating that a water-borne pheromone may be the stimulating agent. These findings confirm the contention of Crisp (1967) that gregarious setting occurs inC. virginica.

Effect of shaking speed and type of closure on shake flask cultures.

Abstract: Growth of microorganisms and biosynthesis of microbial products in shake flasks may be limited by operating conditions which provide inadequate supplies of oxygen. Methods are described for meeting the oxygen requirements of test organisms by using standard baffled flasks with pad-type closures and shaking at relatively high speeds. Growth of Escherichia coli B in a rich medium and production of candidin by Streptomyces viridoflavus were the test systems used. Flasks shaken at 230 to 385 rev/min gave sulfite oxidation rates of 1 to 8 mmoles of oxygen per liter per min over a useful working volume range (40 to 150 ml in 300-ml flasks). These rates are as high as those obtained in agitated fermentors under usual operating conditions.

Approximate Screening Functions in Metals

Abstract: A variational principle is used to "solve" an approximate integral equation for the screening functions of the electron gas. It is shown that the simplest possible trial function gives a solution to the equation for the dielectric constant which is exact in both the limits of small and large momentum transfers. The results are compared with other calculations. It is shown that the approximation developed recently by Kleinman is quite good in the static large-$k$ limit, but otherwise incorrect. The dielectric constant derived from the variational calculation is used to derive an expression for the ground-state energy; this expression is similar in its essential features to the interpolation schemes of Hubbard and of Nozi\`eres and Pines, even though the Hubbard approximation considerably underestimates the exchange enhancement of the vertex function at large $k$. Finally, it is suggested that similar variational principles may have other uses, as in the paramagnon problem.

Decreased neutrophils and megakaryocytes in anemic mice of genotype W/W.

Abstract: The concentration of neutrophils and megakaryocytes was determined in the marrow of anemic mice of genotype W/Wv and their normal (+/+) litter mates. In all groups studied, the humerus of W/Wv mice contained significantly less neutrophils and megakaryocytes than did normal animals. Blood neutrophil concentration was less in all groups of W/Wv mice but in only one group which was the youngest group studied, did this value differ significantly from normal. The blood and marrow neutrophil response to endotoxin was similar in W/Wv and “+/+” animals. This suggests that the neutrophilic system of W/Wv mice responds to this stimulus in a relatively normal manner, much as their erythroid system responds to hypoxia, and androgens.

Cell-free peroxidases in soil

Abstract: The method of Galstyan for assay of peroxidase activity in soil was critically evaluated and found to be unsatisfactory. An alternate method was developed and utilized for measurement of peroxidase activity of unsterile and filter-sterilized soil extracts. The results indicate that substantial amounts of cell-free peroxidases are present in natural soils.

Alterations in the Phospholipid Composition of Escherichia coli B During Growth at Different Temperatures

Abstract: The major phospholipid classes of Escherichia coli B, phosphatidyl ethanolamine, cardiolipin, and phosphatidyl glycerol, were quantitated at different stages of the growth cycle. The organisms were incubated at both 27 and 37 C. Significant differences were observed both in the amounts of total lipid phosphorus per gram (dry weight) of cells and in the relative percentages of the individual phospholipids. At 37 C the total amount of lipid phosphorus decreased significantly throughout the growth cycle. However, at 27 C total lipid phosphorus accumulated. The patterns of the three major phospholipid classes of Escherichia coli exhibited complex quantitative changes. In addition, some evidence based on glycerol to phosphate molar ratios indicated that phosphatidyl glycerolphosphate replaced phosphatidyl glycerol during the late growth stages of E. coli B when grown at 27 C. A comparative analysis of phospholipid and fatty acid patterns led to a hypothesis attempting to explain some reported variations in the lipid composition of E. coli under different conditions of growth.

Adenoviruses: the nature of the virion and of controlling factors in productive or abortive infection and tumorigenesis.

Abstract: Publisher Summary The chapter discusses the various properties of the adenoviruses, such as the nature of virion and the controlling factors in the productive or abortive infection. The dissection of the virion and its component parts, summarized in this chapter, has provided essential markers for the exploration and correlation of these biological variables, the mapping of phage chromosomes, based on deletions in conditional lethal mutants, required the structural and functional identification of phage precursors and subunits, such that each identifiable moiety of the adenovirion will help in relating biological activity to structural and molecular properties of the viral genomes. For a full understanding of the biology of adenovirus infection, as of other virus-cell systems, it is important to recognize that uniformity and synchrony of response is a deliberately created experimental artifact resulting only from high multiplicity infection of competent cells. This type of response may be absent in natural infections, which does not occur under conditions of low multiplicity infection, and may be fundamentally irrelevant in adenoviral tumorigenesis and abortive infection. For the sake of simplicity, any infection with complete adenovirus particles not leading to production of infectious progeny will be defined as “abortive.” The term “complete” in this context, implies that the same virions can induce productive infection in some suitable indicator cell. Hence, these viruses can be characterized, operationally, as host dependent conditionally lethal, either the permissive host cell supplies some function needed for virus replication that the non permissive cell lacks, or the latter imposes a restriction not present in the permissive one. Both alternatives could, in a purely descriptive way, satisfy the need for working hypotheses to explain the various examples of abortive infection with adenoviruses.

Polymorphism in isotactic polypropylene

Abstract: The conditions under which a given form of any of the three distinct polymorphic crystalline phases of isotactic polypropylene can be obtained have been investigated. The relationship between crystallization conditions and the formation of a given crystalline phase is discussed. Evidence is cited in support of the hypothesis that the β-form of isotactic polypropylene can be produced only when appropriate nucleating materials are present. It is shown that under particular high-pressure crystallization conditions a triclinic γ-phase can be produced that does, not convert to the monoclinic α-phase either by action of heat or mechanical stress. Based on considerations of stability, density, and structure, it is suggested that the equilibrium crystal form of the polymer is the γ-form rather than the α-form which is ordinarily observed.