Lack Of Positive Correlation Research Articles

Coexistence of Earth‐origin O+ and solar wind‐origin H+/He++ in the distant magnetotail

In the lobe/mantle region at ∼159 RE away from the Earth during a geomagnetically disturbed period, we have found the coexistence of three ion species, H+, He++, and O+, streaming tailward with nearly the same flow velocity ∼200–500 km/s. Both H+ and O+ ions are detected almost continuously from near plasma sheet to near magnetopause region. From a positive correlation between the proton density and their velocity component parallel to the magnetic field VH+║, we conclude that most of protons have come from the solar wind. The existence of He++ further supports this conclusion, which implies the importance of solar wind contribution to the magnetotail. The existence of O+, on the other hand, suggests that the ions of ionospheric origin have mixed with those of solar wind origin. The lack of positive correlation between O+ density and VO+║ is consistent with the idea that O+; ions have some source mechanism different from that of protons. Simultaneously, curious velocity differences are also observed: VO+¶ appears to be often faster than VH+║; by ΔV¶ = 20–30 km/s. This observation may provide a key for further discussion.

Calcium effect on number, dimension and activity of nucleoli in cortex cells of pea ( Pisum sativum L.) roots after treatment with heavy metals

Calcium effect on nucleolar activity in the presence of heavy metals (Cd, Cr, Pb) was assessed by determining the variation in number and diameter of nucleoli in cortex cells of Pisum sativum. The ability of cells to incorporate 3H-uridine and 3H-lysine into nuclei, nucleoli and cytoplasm was also determined. The presence of metals increased the number of cells with one nucleolus and lowered the number of cells with two but mostly with three nucleoli. Calcium added to chromium diminished the number of cells with one nucleolus increasing those with two nucleoli when this ion was present in cadmium solution. The size of a single nucleolus as well as a total nucleolar dimension in the nucleus of cells both in calcium and those treated with metals underwent reduction as its number increased. Calcium alone and that added to metal solutions enhanced the size of a single nucleolus as well as the total nucleolar dimension. In material treated with heavy metals or after calcium addition the intensity of RNA synthesis in nucleolus and radioactivity of nucleus was positively correlated with the number of nucleoli. Disturbances in this relation within nucleolus and nucleus appeared in the presence of cadmium and lead as well as after calcium addition. No relation between the number of nucleoli and radioactivity of cytoplasm was seen in all experimental series except calcium alone. The lack of positive correlation between the number of nucleoli and radioactivity of nucleoli, nuclei and cytoplasm was also observed after incubation with 3H-lysine. Exception was nucleolus in the presence of calcium or chromium and lead after calcium addition.

Lack of positive correlation between placental blood flow and mean arterial pressure in the non-anaesthetised guinea pig near term; an indication for autoregulation?

The objective of the present study was to evaluate whether placental blood flow (PBF) decreases or increases, in response to a fall or rise in mean arterial pressure (MAP), respectively, in an unanaesthetised animal model with a haemochorial placenta. Such a response would support the absence of autoregulation of placental blood flow for changes in mean arterial pressure. To this end, 31 late-pregnant guinea pigs were subjected to isovolemic haemodilution, a sham procedure or isovolemic haemoconcentration, after adequate recovery from instrumentation. The percentage change from baseline in PBF (δPBF, %), was compared between animals with a fall in MAP, in response to haemodilution or the sham procedure (MAP-fall, n = 8, mean δMAP −11 ± 7%) and those with a rise in MAP, following haemoconcentration (MAP-rise, n = 10, mean δMAP + 15 ± 8%). In addition, the percentage change in the blood flow to the myocardium, gastrointestinal tract, adrenals, kidneys, brain, skin, carcass and myometrium was compared between the MAP-fall and the MAP-rise group. The direction of the change in PBF did not differ between the MAP-fall and the MAP-rise group. In this respect, the distribution of δPBF over the two groups was comparable with that observed for the myocardium, gastrointestinal tract, adrenals, skin, carcass and myometrium. The blood flow to the kidneys and the brain varied in response to the change in haematocrit. The results of this study show that PBF varies independently from MAP. This observation supports the idea that the blood flow to the labyrinthine placenta of the awake and healthy guinea pig near term may be autoregulated for hydrostatic inflow pressure, at least over the spectrum of arterial pressures observed in the present study.

Variation in Resource Abundance Affects Capture Rates of Birds in Three Lowland Habitats in Costa Rica

-We examined temporal variation in abundance of understory birds and fruiting plants in young (5-7 yr) and old (25-35 yr) successional habitats and in intact, lowland rain forest at Estacion Biologica La Selva, Costa Rica, between January 1985 and May 1986. Fruit abundance varied seasonally in each habitat but was consistently greatest in the youngest site. Frugivores and nectarivores accounted for four (forest and older successional) or five (younger successional) of the five most frequently captured bird species in each habitat. Capture rates of arboreal frugivores and arboreal frugivore-insectivores were greatest in the youngest site and were not different between older habitats. Temporal variation in capture rates of frugivores resulted from habitat shifts by resident individuals and from arrival and departure of altitudinal and latitudinal migrants. Capture rates of frugivores correlated with fruit abundance in forest and the older successional habitat but not in the youngest site. Capture rates of nectarivores and insectivores varied over time and among habitats, but rates showed no correlation with capture rates of frugivores. The lack of positive correlations in seasonal capture rates among trophic groups and the correlation between frugivores and fruit abundance support the view that temporal and spatial variation in bird abundance in tropical bird communities is at least partially in response to variation in resource abundance. Received 3 November 1989, accepted 28 July 1990. BIRD populations vary in abundance over time and space in both temperate (e.g. Kendeigh 1982, Holmes et al. 1986, many others) and tropical habitats (e.g. Fogden 1972; Karr 1976; Leighton and Leighton 1983; Martin and Karr 1986a; Loiselle 1987a, 1988; Loiselle and Blake 1991; but see Greenberg and Gradwohl 1986). Fluctuations in abundance arise from variation in population processes (Orell and Ojanen 1983, Faaborg et al. 1984, DeSante and Geupel 1987) and from movement of individuals among habitats (Karr and Freemark 1983, Wheelwright 1983, Recher and Holmes 1985, Loiselle et al. 1989, Loiselle and Blake 1991). Such movements may represent random redistribution of individuals (Wiens and Rotenberry 1978, Wiens 1984), but such hypotheses often have been advanced in the absence of data on food abundance. Individual movements may instead reflect responses to changes in microclimatic conditions (Karr and Freemark 1983, Petit 1989) or to temporal and spatial variation in food (e.g. Leighton and Leighton 1983, Wheelwright 1983, 1 Present address: Department of Biology, University of Missouri-St. Louis, 8001 Natural Bridge Road, St. Louis, Missouri 63121 USA. Recher and Holmes 1985, Loiselle and Blake 1991). Most studies lack concurrent data on fluctuations in both bird population levels and food abundance (but see Wheelwright 1983; Stiles 1985a; Levey 1988a, b; Loiselle and Blake 1991). Consequently, a more direct examination of avian responses to variations in food supply is central to resolving the controversial role of food as an influence in organization of species assemblages (Wiens 1984, Martin 1986). To address this controversy, we used data from concurrent studies on temporal and spatial variation in abundance of tropical frugivores and fruit among three habitats in Costa Rica. We focus mainly on frugivores, but for comparison we examined seasonal rhythms of bird groups (nectarivores, insectivores) that rely on different resources. Tropical frugivores are particularly appropriate for the study of the influence of resource availability on consumer populations because their diets can be readily determined (e.g. Wheelwright et al. 1984, Loiselle and Blake 1990) and their resources (fruit) accurately measured (Blake et al. 1990). Fruit-eating birds also are a major component of many tropical communi114 The Auk 108: 114-130. January 1991 This content downloaded from 157.55.39.104 on Sun, 19 Jun 2016 05:47:31 UTC All use subject to http://about.jstor.org/terms January 1991] Birds and Fruits in Lowland Tropics 115 ties (e.g. Stiles 1985b, Loiselle 1988, Karr et al. 1990, Loiselle and Blake 1991), and frugivores disperse seeds from a large proportion of tropical shrubs and trees that produce fruits (e.g. Howe and Smallwood 1982, Stiles 1985b). Thus, it is important both from theoretical and practical standpoints to better understand the interactions between frugivorous birds and fruitproducing plants (Stiles 1985b, c). STUDY AREA AND METHODS

Steroidogenesis and cAMP production in isolated avian granulosa cells during follicular maturation: lack of positive correlation.

Luteinizing hormone- and forskolin-induced acute steroidogenesis and cAMP production were studied in dispersed chicken granulosa cells in relation to follicular maturation. Cells isolated from the 6 largest preovulatory follicles (F1-F6) were used in this study. Basal steroidogenic activity increased with progressive maturation of the follicle without a corresponding rise in basal cAMP production. Both LH- and forskolin-promoted progesterone production was directly correlated with the maturational stage of the follicle and the dose of the agonists. On the other hand, LH caused the greatest increase in cAMP production in the third and fourth largest preovulatory follicles (F3-F4), whereas forskolin-stimulated cAMP accumulation was maximal in the least mature granulosa cells (F5-F6). Thereafter it decreased in proportion with follicular development. It is concluded that LH-induced acute steroidogenesis in chicken granulosa cells is not positively correlated with cAMP production during the last few days of follicular maturation. Therefore the steroidogenic responsiveness of granulosa cells of the largest follicle to LH cannot be ascribed solely to receptor-coupled adenylate cyclase activity. As shown by the forskolin experiment, the intrinsic activity of the adenylate cyclase-cAMP system is greatest in the small F5, F6 follicles which respond only minimally in terms of steroidogenesis to either a receptor dependent agonist (LH) or a nonreceptor agonist (forskolin).

Stereotypy in Human Randomization and Spontaneous Sequencing of Responses

dancy as a measure of stereotypy in human performance on randomization and spontaneous sequencing tasks. In the latter study they hypothesized that in a randomization task the control over stereotypy is limited by a subject's ability to randomize and in a spontaneous task by both his ability to randomize and his willingness, suggesting a distinction between cognitive and attitudinal (volitional) components of stereotypy. Higher stereotypy scores on spontaneous sequencing were hypothesized to be related to the attitudinal component. The present study was done to determine the correlation between the tasks of randomization and spontaneous activity, using the information-theoretic measure of redundancy as a measure of stereotypy. A relative lack of positive correlation would be consistent with the notion of cognitive and attitudinal components of stereotypy as independent factors of stereotypy, while a significant positive correlation would indicate a common factor of stereotypy in both types of tasks. Subjects were 106 undergraduates of both sexes; 52 were given the spontaneous sequencing task first, followed by the randomization task. The remaining 54 subjects were tested in the reverse order. Both tasks were those described earlier (1. 2). When the spontaneous sequencing task was presented first, the product-moment correlation was -.I09 (p > .05), but when the randomization task was first, 7 was .640 (p < .01). This discrepancy requires some explanation. The spontaneous sequencing task is induced by non-specific instructions (the subject does whatever he pleases), while the randomization task is preceded by specific randomization instructions (subject has to apply his ability to randomize the sequence). While the transition from non-specific to specific tasks would not be expected to contaminate the specific task (namely, randomization), the converse would not be equally logical. An initial specific task would be expected to carry over to the following non-specific task because subjects habituate to one particular mode of responding which is also consistent with and allowed by the non-specific instructions (namely, spontaneous sequencing instructions). Tbe correlation of .640 when the randomization task is first, should be interpreted as spurious (albeit on an ex port facto basis). This interpretation is supported by an inspection of the means. When the spontaneous sequencing task was second, the redundancy dropped to a low of .430 (compared with .659 when the same task was first), a level more consistent with redundancy obtained on randomization (.346 and .296, respectively). A lack of positive correlation, when the randomization follows the spontaneous sequencing task, supports the contention that the stereotypy in the two tasks is of two different kinds, namely, of a cognitive and of an attitudinal (volitional) type.

Geochemical evolution of copper-bearing granitic rocks of Guichon Creek Batholith, British Columbia, Canada

The Guichon Creek batholith, located in south-central British Columbia, is host to numerous porphyry copper deposits that are considered as being closely related to the pluton. Variations in major and trace element distribution are consistent with a model of crystallization-fractionation of a K-poor calc-alkaline magma of intermediate composition. Relatively low Rb and Rb/Sr values, and high K/Rb ratios are consistent with Sr isotopic ratios that suggest a subcrustal source region for the generation of the magma, probably by partial melting of subducted oceanic crust at relatively shallow depths.Cu, like other femic elements, (Zn, Mn, V, Ni, Co, Ti) generally decreases with increasing fractionation, which reflects normal differentiation trends. The apparent lack of positive correlation between Cu contents of rocks and ore potential of intrusive units may be explicable if mineralization is regarded as an independent by-product of magma generation, rather than the result of differentiation processes. Close relationships between trace metal values and degree of fractionation emphasize the need for assigning different background values to each intrusive unit, during geochemical exploration.

Lack of positive correlation between cell respiration and cytochrome content in galactose-grown Saccharomyces cerevisiae

FEBS LettersVolume 55, Issue 1-2 p. 42-45 Full-length articleFree Access Lack of positive correlation between cell respiration and cytochrome content in galactose-grown Saccharomyces cerevisiae A.V. Galkin, A.V. Galkin Department of Biokinetics, Laboratory of Bioorganic Chemistry, Lomonosov State University, Moscow, USSRSearch for more papers by this authorT.A. Makhlis, T.A. Makhlis Department of Biokinetics, Laboratory of Bioorganic Chemistry, Lomonosov State University, Moscow, USSRSearch for more papers by this authorA.S. Zubatov, A.S. Zubatov Department of Biokinetics, Laboratory of Bioorganic Chemistry, Lomonosov State University, Moscow, USSRSearch for more papers by this authorV.N. Luzikov, V.N. Luzikov Department of Biokinetics, Laboratory of Bioorganic Chemistry, Lomonosov State University, Moscow, USSRSearch for more papers by this author A.V. Galkin, A.V. Galkin Department of Biokinetics, Laboratory of Bioorganic Chemistry, Lomonosov State University, Moscow, USSRSearch for more papers by this authorT.A. Makhlis, T.A. Makhlis Department of Biokinetics, Laboratory of Bioorganic Chemistry, Lomonosov State University, Moscow, USSRSearch for more papers by this authorA.S. Zubatov, A.S. Zubatov Department of Biokinetics, Laboratory of Bioorganic Chemistry, Lomonosov State University, Moscow, USSRSearch for more papers by this authorV.N. Luzikov, V.N. Luzikov Department of Biokinetics, Laboratory of Bioorganic Chemistry, Lomonosov State University, Moscow, USSRSearch for more papers by this author First published: July 15, 1975 https://doi.org/10.1016/0014-5793(75)80952-5Citations: 7AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat References 1 B. Ephrussi, P.P. Slonimski, Biochim. Biophys. Acta, 6, (1950), 256– 267. 2 D.B. Roodyn, D. Wilkie, The Biogenesis of Mitochondria (1968), Methuen Co, Ltd 3 J. Jayaraman, C. Cotman, H.R. Mahler, C.W. Sharp, Arch. Biochem. Biophys., 116, (1966), 224– 251. 4 R. Marchant, D.G. Smith, Biol. Rev., 43, (1968), 459– 477. 5 V.N. Luzikov, A.S. Zubatov, E.I. Rainina, L.E. Bakeyeva, Biochim. Biophys. Acta, 245, (1971), 321– 334. 6 V.N. Luzikov, A.S. Zubatov, E.I. Rainina, Dokl. Akad. Nauk SSSR, 195, (1970), 1453– 1455. 7 V.N. Luzikov, A.S. Zubatov, E.I. Rainina, J. Bioenerg., 5, (1973), 129– 149. 8 A. Tzagoloff, J. Biol. Chem., 244, (1969), 5020– 5026. 9 R.W. Estabrook, B. Mackler, J. Biol. Chem., 224, (1957), 637– 648. 10 R.K. Poole, D. Lloyd, B. Chance, Biochem. J., 138, (1974), 201– 210. 11 B. Mackler, P.J. Collipp, H.M. Duncan, N.A. Rao, F.M. Huennekens, J. Biol. Chem., 237, (1962), 2968– 2974. 12 O.H. Lowry, N.J. Rosebrough, A.L. Farr, R.J. Randall, J. Biol. Chem., 193, (1951), 265– 275. 13 T.G. Cartledge, D. Lloyd, M. Erecinska, B. Chance, Biochem. J., 130, (1972), 739– 747. 14 B. Ephrussi, P.P. Slonimski, Y. Yotsuyanagy, J. Tavlitzki, Compt. Rend. Trav. Lab. Carlsberg, 26, (1956), 87– 98. 15 M.F. Utter, E.A. Duell, C. Bernofsky, R.V. Mills Aspects of Yeast Metabolism (1966), Blackwell Scientific Publication Oxford 197– 215. 16 W. Rouslin, G. Schatz, Biochem. Biophys. Res. Commun., 37, (1969), 1002– 1007. 17 C.P. Lee, R.W. Estabrook, B. Chance, Biochem. Biophys. Acta, 99, (1965), 32– 45. Citing Literature Volume55, Issue1-2July 15, 1975Pages 42-45 ReferencesRelatedInformation

Lack of positive correlation between adenyl cyclase activity and iodide transport in rat thyroids.

Adenyl cyclase activity was determined in 9000 X g pellets of thyroid homogenates from a) intact rats that received no medication vs propylthiouracil (PTU) treatment for 20 days; b) untreated hypophysectomized rats vs similar rats injected with TSH (1 U) and PTU (20 mg) daily for 3 days, and c) hypophysectomized rats which were given no TSH or a single dose (1 U) of the hormone. In experiment c), thyroids for enzyme assay were removed 10 or 30–45 min after the injection of TSH. Thyroidal iodide transport was measured by the thyroid—serum radioiodide concentration (T/S) ratio, which averaged 69 vs 219 in the intact and PTU—treated rats, 5.2 vs 185 in untreated hypophysectomized rats and those injected with TSH+ PTU, and 4.4 vs 81 and 5.2 vs 78, respectively, in 2 groups of hypophysectomized rats and similar rats treated with TSH 24 hr before they were killed. In spite of the stimulation of the thyroid by endogenous or exogenous TSH reflected by these marked rises in the T/S ratios, adenyl cyclase activity ...

Effects of neonatal and adult treatments with gonadal hormones on choline acetylase activity in brain regions of male mice after fighting.

The effects of neonatal and adult administrations of gonadal hormones were investigated on the activity of regional brain choline acetylase (ChAc) and fighting behavior in the mouse. It was found that, generally, the hormonal treatments resulted in consistent increases in hypothalamic and hippocampal ChAc, and inconsistent changes in cortical ChAc. Increases in enzyme activity were not accompanied by similar increases in fighting. There was a lack of positive correlation between a particular gonadal hormone used, the increase in ChAc and fighting A number of hypotheses are proposed.