Showing papers by "Cornell University published in 1988"
TL;DR: This paper summarizes the insights gained in automatic term weighting, and provides baseline single term indexing models with which other more elaborate content analysis procedures can be compared.
Abstract: The experimental evidence accumulated over the past 20 years indicates that textindexing systems based on the assignment of appropriately weighted single terms produce retrieval results that are superior to those obtainable with other more elaborate text representations. These results depend crucially on the choice of effective term weighting systems. This paper summarizes the insights gained in automatic term weighting, and provides baseline single term indexing models with which other more elaborate content analysis procedures can be compared.
9,460 citations
Journal Article•
TL;DR: Testing as a sole agent, IFN-gamma was the only one of the 12 cytokines capable of inducing both NO2- and H2O2 release and the pathways leading to secretion of H2 O2 and No2- are independent.
Abstract: The capacity of 12 cytokines to induce NO2- or H2O2 release from murine peritoneal macrophages was tested by using resident macrophages, or macrophages elicited with periodate, casein, or thioglycollate broth. Elevated H2O2 release in response to PMA was observed in resident macrophages after a 48-h incubation with IFN-gamma, TNF-alpha, TNF-beta, or CSF-GM. Of these, only IFN-gamma induced substantial NO2- secretion during the culture period. The cytokines inactive in both assays under the conditions tested were IL-1 beta, IL-2, IL-3, IL-4, IFN-alpha, IFN-beta, CSF-M, and transforming growth factor-beta 1. Incubation of macrophages with IFN-gamma for 48 h in the presence of LPS inhibited H2O2 production but augmented NO2- release, whereas incubation in the presence of the arginine analog NG-monomethylarginine inhibited NO2- release but not H2O2 production. Although neither TNF-alpha nor TNF-beta induced NO2- synthesis on its own, addition of either cytokine together with IFN-gamma increased macrophage NO2- production up to six-fold over that in macrophages treated with IFN-gamma alone. Moreover, IFN-alpha or IFN-beta in combination with LPS could also induce NO2- production in macrophages, as was previously reported for IFN-gamma plus LPS. These data suggest that: 1) tested as a sole agent, IFN-gamma was the only one of the 12 cytokines capable of inducing both NO2- and H2O2 release; 2) the pathways leading to secretion of H2O2 and NO2- are independent; 3) either IFN-gamma and TNF-alpha/beta or IFN-alpha/beta/gamma and LPS can interact synergistically to induce NO2- release.
2,829 citations
Book•
01 Jan 1988TL;DR: The authors showed that looking out for Number One may require that we look out for others, too, finding evidence in our emotional acts, like the blush on telling a lie, they can serve as hard-to-fake signals of a commitment to social values.
Abstract: The "Me" generation has justified itself by appealing to social scientists who see selfishness as the only rational basis for action. But what are we to make of selfless acts in business, personal life, even politics? In this provocative book, Robert Frank shows us that looking out for Number One may require that we look out for others, too. He finds his evidence in our emotional acts. Like the blush on telling a lie, they can serve as hard-to-fake signals of a commitment to social values. We recognize these signs; we know people we trust; and if we can identify trustworthy fellows we can reject those who do not merit our faith.
2,082 citations
1,912 citations
TL;DR: The first use of a complete RFLP linkage map to resolve quantitative traits into discrete Mendelian factors, in an interspecific back-cross of tomato is reported, broadly applicable to the genetic dissection of quantitative inheritance of physiological, morphological and behavioural traits in any higher plant or animal.
Abstract: The conflict between the Mendelian theory of particulate inheritance and the observation of continuous variation for most traits in nature was resolved in the early 1900s by the concept that quantitative traits can result from segregation of multiple genes, modified by environmental effects. Although pioneering experiments showed that linkage could occasionally be detected to such quantitative trait loci (QTLs), accurate and systematic mapping of QTLs has not been possible because the inheritance of an entire genome could not be studied with genetic markers. The use of restriction fragment length polymorphisms (RFLPs) has made such investigations possible, at least in principle. Here, we report the first use of a complete RFLP linkage map to resolve quantitative traits into discrete Mendelian factors, in an interspecific back-cross of tomato. Applying new analytical methods, we mapped at least six QTLs controlling fruit mass, four QTLs for the concentration of soluble solids and five QTLs for fruit pH. This approach is broadly applicable to the genetic dissection of quantitative inheritance of physiological, morphological and behavioural traits in any higher plant or animal.
1,546 citations
TL;DR: Electrolytic and ibotenic acid lesions of the LH demonstrate that neurons in the LH are involved in the autonomic, but not the behavioral, conditioned response pathway, whereas neurons inThe caudal CG are involvedIn the behavioral and autonomic pathway, although different efferent projections of the central amygdala thus appear to mediate the behavioraland autonomic concomitants of conditioned fear.
Abstract: The purpose of the present study was to determine whether lesions of areas projected to by the central amygdaloid nucleus (ACE) would disrupt the classical conditioning of autonomic and/or behavioral emotional responses. The areas studied included 3 projection targets of the ACE: the lateral hypothalamic area (LH), midbrain central gray (CG) region, and bed nucleus of the stria terminalis (BNST). Lesions were made either electrolytically or by microinjection of ibotenic acid, which destroys local neurons without interrupting fibers of passage. Two weeks later, the animals were classically conditioned by pairing an acoustic stimulus with footshock. The next day, conditioned changes in autonomic activity (increases in arterial pressure) and emotional behavior ("freezing," or the arrest of somatomotor activity) evoked by the acoustic conditioned stimulus (CS) were measured during extinction trials. Electrolytic and ibotenic acid lesions of the LH interfered with the conditioned arterial pressure response, but did not affect conditioned freezing. Electrolytic lesions of the rostral CG disrupted conditioned freezing but not conditioned changes in arterial pressure. Ibotenic acid injected into the rostral CG reduced neither the arterial pressure nor the freezing response. Injection of ibotenic acid in the caudal CG, like electrolytic lesions of the rostral CG, disrupted the freezing, but not the arterial pressure response. Injection of ibotenic acid into the BNST had no effect on either response. These data demonstrate that neurons in the LH are involved in the autonomic, but not the behavioral, conditioned response pathway, whereas neurons in the caudal CG are involved in the behavioral, but not the autonomic, pathway. Different efferent projections of the central amygdala thus appear to mediate the behavioral and autonomic concomitants of conditioned fear.
1,540 citations
TL;DR: In this article, the wall region of a turbulent boundary layer is modelled by expanding the instantaneous field in so-called empirical eigenfunctions, as permitted by the proper orthogonal decomposition theorem.
Abstract: We have modelled the wall region of a turbulent boundary layer by expanding the instantaneous field in so-called empirical eigenfunctions, as permitted by the proper orthogonal decomposition theorem (Lumley 1967, 1981). We truncate the representation to obtain low-dimensional sets of ordinary differential equations, from the Navier–Stokes equations, via Galerkin projection. The experimentally determined eigenfunctions of Herzog (1986) are used; these are in the form of streamwise rolls. Our model equations represent the dynamical behaviour of these rolls. We show that these equations exhibit intermittency, which we analyse using the methods of dynamical systems theory, as well as a chaotic regime. We argue that this behaviour captures major aspects of the ejection and bursting events associated with streamwise vortex pairs which have been observed in experimental work (Kline et al. 1967). We show that although this bursting behaviour is produced autonomously in the wall region, and the structure and duration of the bursts is determined there, the pressure signal from the outer part of the boundary layer triggers the bursts, and determines their average frequency. The analysis and conclusions drawn in this paper appear to be among the first to provide a reasonably coherent link between low-dimensional chaotic dynamics and a realistic turbulent open flow system.
1,271 citations
TL;DR: In this paper, the authors present a data structure for yield trials with both significant main effects and a significant genotype x environment (GE) interaction, which is not always effective with this data structure: the usual analysis of variance (ANOVA), having a merely additive qualitative model, identifies the GE interaction as a source but does not analyze it; principal components analysis (PCA), on the other hand, is a multiplicative model and hence contains no sources for additive qualitative effects.
Abstract: Yield trials frequently have both significant main effects and a
significant genotype x environment (GE) interaction. Traditional
statistical analyses are not always effective with this data structure:
the usual analysis of variance (ANOVA), having a merely additive
model, identifies the GE interaction as a source but does not analyze
it; principal components analysis (PCA), on the other hand is a
multiplicative model and hence contains no sources for additive
genotype or environment main effects; and linear regression (LR)
analysis is able to effectively analyze interaction terms only where
the pattern fits a specific regression model. The consequence of fitting
inappropriate statistical models to yield trial data is that the
interaction may be declared nonsignificant, although a more appropriate
analysis would find agronomically important and statistically
significant patterns in the interaction. Therefore, agronomists and
plant breeders may fail to perceive important interaction effects.
1,269 citations
TL;DR: Twenty-one percent of 292 patients with untreated borderline hypertension were found to have normal daytime ambulatory pressures, and patients with white coat hypertension were defined as having "white coat" hypertension, and they were more likely to be female and younger, to weigh less, and to be more recently diagnosed.
Abstract: Twenty-one percent of 292 patients with untreated borderline hypertension (clinic diastolic blood pressures persistently between 90 and 104 mm Hg) were found to have normal daytime ambulatory pressures (defined from a population of normotensive subjects). These patients were defined as having "white coat" hypertension, and they were more likely to be female and younger, to weigh less, and to be more recently diagnosed than patients whose pressure was elevated both in the clinic and during ambulatory monitoring. Patients with white coat hypertension did not show a generalized increase of blood pressure lability, nor an exaggerated pressor response while at work. The phenomenon is more pronounced when blood pressure is measured by a physician than by a technician. In such patients, the pressor response may be relatively specific to the physician's office and lead to significant misclassification of hypertension.
1,150 citations
TL;DR: In this paper, topographic data are combined with data on structure magmatism, seismicity, and paleomagnetism to support a simple kinematical model for the late Cenozoic evolution of the central Andes.
Abstract: Topographic data are combined with data on structure magmatism, seismicity, and paleomagnetism to support a simple kinematical model for the late Cenozoic evolution of the central Andes. The model interrelates Andean uplift, a changing geometry of the subducted Nazca plate, and a changing outline of the leading edge of the South American plate. It is argued that the late Cenozoic uplift of the Andes is a result of thermal thinning of the lithosphere and crustal thickening produced by crustal shortening.
1,131 citations
TL;DR: In recent years, there has been a proliferation of empirical studies documenting unexpected or anomalous regularities in security rates of return as discussed by the authors, including seasonal regularities related to the time of the day, the day of the week, and the turn of the year.
Abstract: In recent years there has been a proliferation of empirical studies documenting unexpected or anomalous regularities in security rates of return. In addition to the widely studied relation between firm size and rate of return,1 these include seasonal regularities related to the time of the day [Harris (1986)], the day of the week [see Ball and Bowers (1986), Cross (1973), French (1980), Gibbons and Hess (1981), Jaffe and Westerfield (1985), Keim and Stambaugh (1984), and Lakonishok and Levi (1982)], the time of the month [Ariel (1987)], and the turn of the year [see Haugen and Lakonishok (1988), Jones, Pearce, and Wilson (1987), Lakonishok
TL;DR: In this article, the Gibbs-ensemble Monte Carlo simulation methodology for phase equilibrium calculations proposed by Panagiotopoulos is generalized and applied to mixture and membrane equilibria, and an alternative derivation of the Gibbs simulation criteria based on the limiting distributions for the appropriate statistical mechanical ensembles is presented.
Abstract: The Gibbs-ensemble Monte Carlo simulation methodology for phase equilibrium calculations proposed by Panagiotopoulos [1] is generalized and applied to mixture and membrane equilibria. An alternative derivation of the Gibbs simulation criteria based on the limiting distributions for the appropriate statistical mechanical ensembles is presented. The method is then generalized for the calculation of phase equilibria of mixtures by simulation in a constantpressure Gibbs ensemble and the calculation of equilibria across semipermeable membranes with an imposed osmotic pressure difference. The method is used to calculate phase equilibria for binary mixtures of Lennard-Jones molecules. Good agreement is found with published results obtained using other simulation techniques. The computer time required for the Gibbs method is only a small fraction of the corresponding requirement for previously available simulation techniques. Calculations for simple osmotic systems are performed for the first time by simulation, ...
TL;DR: It is discovered that rice DNA is less C-methylated than tomato or maize DNA, suggesting the notion that a large fraction of the rice genome (approximately 50%) is single copy.
Abstract: We report the construction of an RFLP genetic map of rice (Oryza sativa) chromosomes. The map is comprised of 135 loci corresponding to clones selected from a PstI genomic library. This molecular map covers 1,389 cM of the rice genome and exceeds the current classical maps by more than 20%. The map was generated from F2 segregation data (50 individuals) from a cross between an indica and javanica rice cultivar. Primary trisomics were used to assign linkage groups to each of the 12 rice chromosomes. Seventy-eight percent of the clones assayed revealed RFLPs between the two parental cultivars, indicating that rice contains a significant amount of RFLP variation. Strong correlations between size of hybridizing restriction fragments and level of polymorphism indicate that a significant proportion of the RFLPs in rice are generated by insertions/delections. This conclusion is supported by the occurrence of null alleles for some clones (presumably created by insertion or deletion events). One clone, RG229, hybridized to sequences in both the indica and javanica genomes, which have apparently transposed since the divergence of the two cultivars from their last common ancestor, providing evidence for sequence movement in rice. As a by product of this mapping project, we have discovered that rice DNA is less C-methylated than tomato or maize DNA. Our results also suggest the notion that a large fraction of the rice genome (approximately 50%) is single copy.
TL;DR: Bombardment of three mutants of the chloroplast atpB gene of Chlamydomonas reinhardtii with high-velocity tungsten microprojectiles that were coated with cloned chloropleft DNA carrying the wild-type gene permanently restored the photosynthetic capacity of the algae.
Abstract: Bombardment of three mutants of the chloroplast atpB gene of Chlamydomonas reinhardtii with high-velocity tungsten microprojectiles that were coated with cloned chloroplast DNA carrying the wild-type gene permanently restored the photosynthetic capacity of the algae. In most transformants of one of the mutants, a fragment with a 2.5-kilobase deletion was restored to normal size by a homologous replacement event; in about 25 percent of the transformants the restored restriction fragment was 50 to 100 base pairs smaller or larger than that of wild type. About one-fourth of the transformants of this mutant contained unintegrated donor plasmid when first examined. This plasmid persisted in four different transformants after 65 cell generations of continuous liquid culture but was lost from all transformants maintained on plates of selective medium. The restored wild-type atpB gene remains in all transformants as an integral part of the chloroplast genome and is expressed and inherited normally.
TL;DR: L'apparition d'un nouveau mode localise dans un reseau anharmonique pur est predite, mais possede une energie d'activation plus faible.
Abstract: A new kind of localized mode is proposed to occur in a pure anharmonic lattice. Its localization properties are similar to those of a localized mode for a force-constant defect in a harmonic lattice. These modes, which are thermally generated like vacancies but with much smaller activation energies, may appear at cryogenic temperatures in strongly anharmonic solids such as quantum crystals as well as in conventional solids.
Book•
01 Jul 1988TL;DR: In this paper, the authors present a comprehensive, up-to-date account of computer relaying in power systems, based in part on the author's extensive experience in the field.
Abstract: This text/reference presents a comprehensive, up-to-date account of computer relaying in power systems, based in part on the author's extensive experience in the field. Provides background material on current relaying practices, and covers the mathematical foundations for relaying algorithms. Each chapter contains helpful illustrations, examples, and problems.
TL;DR: Among 11 polypeptide growth factors that regulate angiogenesis, fibrogenesis and other aspects of tissue repair, two proteins that are 71% similar proved to be potent macrophage deactivators: these are transforming growth factor-β1 (TGF- β1) and TGF-β2.
Abstract: Macrophage activation—enhanced capacity to kill, in a cell that otherwise mostly scavenges—is essential for host survival from infection and contributes to containment of tumours. Both microbes and tumour cells, therefore, may be under pressure to inhibit or reverse the activation of macrophages. This reasoning led to the demonstration of macrophage deactivating factors from both microbes1,2 and tumour cells3–5. In some circumstances the host itself probably requires the ability to deactivate macrophages. Macrophages are essential to the healing of wounds and repair of tissues damaged by inflammation. Yet the cytotoxic products of the activated macrophages can damage endothelium, fibroblasts, smooth muscle and parenchymal cells (reviewed in ref. 6). Thus, after an inflammatory site has been sterilized, the impact of macrophage activation on the host might shift from benefit to detriment. These concepts led us to search for macrophage deactivating effects among polypeptide growth factors that regulate angiogenesis, fibrogenesis and other aspects of tissue repair. Among 11 such factors, two proteins that are 71% similar proved to be potent macrophage deactivators: these are transforming growth factor-β1 (TGF- β1) and TGF- β2.
TL;DR: It is shown that the development of ovarian follicles greater than or equal to 5 mm in heifers occurs in waves and that the most common pattern is three waves per estrous cycle.
Abstract: It isnot clearwhether the turnover of ovarianfollicles during the estrouscycle in cattleisContinuous and independent of thephase of the cycle,or whether waves of follicular growth occur at specifictimes of the cycle. To clarifythis controversy, the pattern of growth and regression of ovarian follicles was characterized during a complete estrous cycle in ten heifers by daily ultrasonographic examinations. Follicles � 5 mm were measured and theirrelativelocationswithin the ovary were determined in order tofollow the sequentialdevelopment of each individual follicle. Results indicated the presence of either two (n = 2 heifers), three (n = 7), or four (n = I) waves of follicular growth per cycle.Each wave was characterizedby the development of one large (dominant) follicle and a variable number of smaller (non-dominant) follicles. In the most common pattern observed (threewaves/cycle),thefirst, second, and third waves started on Days 1.9 ± 0.3, 9.4 ± 0.5, and 16.1 ± 0.7 (X ± SEM), respectively. The dominant follicle in the third wave was the ovulatory follicle. The maximal sizeand the growth rateof the dominant folliclein the second wave were significantlylower than inthe other waves, but no significant difference was observed between the first and third waves. For the two heifers that had two follicularwaves/cycle,the waves startedon Days 2 and 11, whereas in the remaining heifer (four waves/cycle), the waves began on Days 2, 8, 14, and 17, respectively. At 0, 1, 2, 3, and 4 days before estrus, the ovulatory follicle was the largest follicle in the ovaries in 100%, 95%, 74%, 35%, and25% offollicular phases monitored, respectively. The relative size of the preovulatory follicle at the completion of luteolysis (progesterone< I ng/ml) was negatively correlated (r = -0.90; p<0.0001) with the interval of time between the end of luteolysis and the luteinizinghormone surge,suggestingthat the length of proestrus isdetermined by the sizeof thepreovulatoryfollicleat the beginning ofproestrus.In conclusion,thisstudy shows thatthe development of ovarian follicles�5 mm in heifers occurs inwaves and thatthe most common pattern isthreewaves per estrouscycle.
TL;DR: Linkage maps based on a common set of restriction fragment length polymorphism markers provide a basis for uniting the previously separate disciplines of tomato and potato genetics and may now be possible to test theories about homologies or orthologies of other genes, including those coding for disease resistance and stress tolerances.
Abstract: Potato (Solanum tuberosum L.) and tomato (Lycopersicon esculentum) are members of the Solanaceae (nightshade family) and have the same basic chromosome number (x = 12). However, they cannot be cross-hybridized and, until now, it was unknown how conserved the gene order might be between these two species. We report herein the construction of a genetic linkage map of potato chromosomes based on genomic and cDNA clones from tomato. The potato map was drawn from segregation data derived from the interspecific cross S. phureja X (S. tuberosum X S. chacoense) (2n = 2x = 24), and consists of 135 markers defining 12 distinct linkage groups. Nearly all of the tomato probes tested hybridized to potato DNA, and in most cases, the copy number of the employed clones was the same in both species. Furthermore, all clones mapped to the same linkage group in both species. For nine chromosomes, the order of loci appears to be identical in the two species, while for the other three, intrachromosomal rearrangements are apparent, all of which appear to be paracentric inversions with one breakpoint at or near the centromere. These results are consistent with cytogenetic theory, previously untested in plants, which predicts that paracentric inversions will have the least negative effect on fitness and thus be the most likely form of chromosomal rearrangements to survive through evolutionary time. Linkage maps based on a common set of restriction fragment length polymorphism markers provide a basis for uniting the previously separate disciplines of tomato and potato genetics. Using these maps, it may now be possible to test theories about homologies or orthologies of other genes, including those coding for disease resistance and stress tolerances.
TL;DR: Data suggests that the exposure of the normal host to cachectin is capable of inducing a pathophysiological syndrome of cachexia, anemia, and inflammation similar to that observed during inflammatory states or malignancy.
Abstract: Cachexia is a potentially lethal syndrome of unknown etiology characterized by anorexia, weight loss, and protein wasting that frequently complicates the treatment of chronic inflammation and cancer Cachectin/TNF was isolated during the search for a humoral mediator of cachexia and found to stimulate the breakdown of energy stores from adipocytes and myocytes in vitro, but the chronic effects of the monokine in vivo are not known Sublethal doses of recombinant human cachectin administered twice daily for 7-10 d caused cachexia in rats, as evidenced by reduced food intake, weight loss, and depletion of whole-body lipid and protein stores Significant anemia is also observed and found to be the result of decreased red blood cell mass, not expanded plasma volume Leukocytosis and histopathological evidence of tissue injury and inflammation are observed in several organs, including omentum, liver, spleen, and heart These data suggests that the exposure of the normal host to cachectin is capable of inducing a pathophysiological syndrome of cachexia, anemia, and inflammation similar to that observed during inflammatory states or malignancy
TL;DR: In this paper, the effect of molecular associations on the phase coexistence properties of hard-sphere fluids with one or two directional, attractive centers is investigated and the critical points and phase equilibria of the associating fluids are determined for various values of the strength and range of the attractive site.
Abstract: The effect of molecular associations on the phase coexistence properties of fluids with one or two directional, attractive centres is investigated. The individual molecules are represented by hard-sphere repulsive cores with off-centre, square-well attractive sites. Such a system’s thermodynamic properties can be calculated by using expressions based on a theory recently proposed by Wertheim. Isothermal-isobaric Monte Carlo simulations of hard-sphere fluids with one or two attractive sites are shown to be in good agreement with the results of the theory. In order to study the system’s phase equilibria using the theory, a simple van der Waals mean-field term is added to account for the dispersion forces. The critical points and phase equilibria of the associating fluids are determined for various values of the strength and range of the attractive site. Furthermore, results are presented for the degree of association in the gas and liquid phases along the vapour pressure curve. The theory can treat fluids with strong hydrogen-bonding associations such as those found in the carboxylic acids, the aliphatic alcohols, hydrogen fluoride, water etc.
TL;DR: In this article, a theoretical approach to surface structure and reactivity is given, which is within the framework of solid-state theory, yet strives for chemical ways of interpretation. But it is quite feasible to construct interaction diagrams for surfaces, and to make frontier orbital arguments, just as for molecules.
Abstract: An account is given of a theoretical approach to surface structure and reactivity that is within the framework of solid-state theory, yet strives for chemical ways of interpretation. One begins from highly delocalized band structures, but introduces interpretational tools (density-of-states decompositions, crystal orbital overlap populations) that allow a tracing of local, chemical acts. It is quite feasible to construct interaction diagrams for surfaces, and to make frontier orbital arguments, just as for molecules. There are some interesting ways in which the surface-adsorbate interaction differs from simple molecular binding---in particular, in the way that two-orbital four-electron and zero-electron interactions can turn into bonding. The surface and bulk acting as a reservoir of electrons or holes at the Fermi level are important in this context. Chemisorption emerges as a compromise in a continuum of bonding whose extremes are dissociative adsorption and surface reconstruction.
TL;DR: In this paper, a spectral forcing scheme is developed to obtain statistically stationary velocity fields in direct numerical simulations of homogeneous, isotropic turbulence, and the results show that the details of the forcing do not have a significant effect on the small-scale structure of the velocity fields.
01 Jun 1988
TL;DR: A reformulated radiosity algorithm is presented that produces initial images in time linear to the number of patches, which brings the use of radiosity for interactive rendering within reach and has implications for the use and development of current and future graphics workstations.
Abstract: A reformulated radiosity algorithm is presented that produces initial images in time linear to the number of patches. The enormous memory costs of the radiosity algorithm are also eliminated by computing form-factors on-the-fly. The technique is based on the approach of rendering by progressive refinement. The algorithm provides a useful solution almost immediately which progresses gracefully and continuously to the complete radiosity solution. In this way the competing demands of realism and interactivity are accommodated. The technique brings the use of radiosity for interactive rendering within reach and has implications for the use and development of current and future graphics workstations.
TL;DR: It was found that the posterior nodal distance was increased in eyes which were treated with negative lenses compared to those treated with positive lenses, and this effect occurs independently in both eyes and it is not due to changes in corneal curvature.
TL;DR: It is shown that a promoter-associated RNA polymerase II molecule is transcriptionally engaged and has formed a nascent RNA chain, but is apparently arrested at that point and unable to penetrate further into the hsp70 gene without heat induction.
TL;DR: In early lactation, dietary CP and energy can profoundly affect milk yield, but current methods of assessing these nutrients are often inadequate to predict animal performance.
TL;DR: The mass spectra of several compounds with molecular weights in the 2500-20,000 Da range were obtained with a quadrupole mass spectrometer equipped with an atmospheric pressure ion source, producingmass spectra containing a series of multiply-charged molecular species.
Abstract: The mass spectra of several compounds with molecular weights in the 2500-20,000 Da range were obtained with a quadrupole mass spectrometer equipped with an atmospheric pressure ion source. Average molecular weight determinations of mellitin (2846.4 Da), a synthetic oligonucleotide (4262.8 Da), myoglobin (16,950.4 Da) and on the subunits of beta-lactoglobulin (18,277.1 Da) requiring as little as 1 pmol of material were achieved with accuracies and precisions of +/- 1 Da. An ion-spray interface was used to produce ions via the ion evaporation process, producing mass spectra containing a series of multiply-charged molecular species. A simple method for calculating the molecular weight of unknown compounds from the spectra containing multiply-charged ions is described.