Showing papers by "University of Rochester published in 1984"
TL;DR: In this article, a formalism for reasoning about actions is proposed that is based on a temporal logic, which allows a much wider range of actions to be described than with previous approaches such as the situation calculus.
2,439 citations
TL;DR: Estimates from the observed signals indicate that a large fraction of target RNAs is both retained in sections and hybridized with probe at saturation, and coupled with measurements of nonspecific background binding of heterologous probes, these data indicate that the method has sufficient sensitivity to detect many moderately abundant mRNAs.
1,621 citations
TL;DR: In this paper, the authors construct a pair of linear examples to study the collapse time of a fixed exchange-rate regime and derive a stochastic model for the same problem.
1,412 citations
TL;DR: It is suggested that the growth inhibitor and the type beta transforming growth factor are similar molecules that can either stimulate or inhibit cell proliferation depending on the experimental conditions.
Abstract: Purified growth inhibitor from BSC-1 cells and type beta transforming growth factor from human platelets are shown to have nearly identical biological activity and to compete for binding to the same cell membrane receptor. These findings suggest that the growth inhibitor and the type beta transforming growth factor are similar molecules. The data also show that the same purified polypeptide can either stimulate or inhibit cell proliferation depending on the experimental conditions.
760 citations
TL;DR: A set of 72 reference strains of Escherichia coli isolated from a variety of hosts and geographical locations has been established for use in studies of variation and genetic structure in natural populations as mentioned in this paper.
Abstract: A set of 72 reference strains of Escherichia coli isolated from a variety of hosts and geographical locations has been established for use in studies of variation and genetic structure in natural populations. The strains, which have been characterized by multilocus enzyme electrophoresis, are representative of the range of genotypic variation in the species as a whole.
712 citations
TL;DR: In this article, the authors used cognitive evaluation theory to compare limit setting styles of either a controlling or informational nature, or no limits, with forty-four first and second-grade children engaged in a painting activity.
Abstract: The imposition of external constraints on an activity has frequently been shown to undermine intrinsic motivation. Given that limits must often be set upon peoples' activities, especially in parenting and education, the present study addressed the question of whether limits can be set without undermining intrinsic motivation for the activity being limited. Using cognitive evaluation theory, contrasting limit setting styles of either a controlling or informational nature, or no limits, were placed upon forty-four first- and second-grade children engaged in a painting activity. The intrinsic motivation, enjoyment, creativity, and quality of artistic production were expected to be decreased by controlling limits relative to informational and no-limits, which were not expected to differ from each other. The results provided substantial support for these predictions, suggesting that limits can be set without undermining intrinsic motivation if they are informational in nature. Support was also found for the consensual assessment of creativity method recently developed by Amabile (1982a). Results ofthe study are discussed along with the general relation between creativity and intrinsic motivation. Recent findings in motivational research suggest that imposing external controls or constraints on an actiyity can haye a deleterious effect on subsequent intrinsic motiyation. Beginning with Deci's (1971) demonstration that tangible rewards for doing a task can negatiyely affect intrinsic motiyation, many other factors that haye a similar impact haye been identified, including symbolic rewards (Lepper, Greene, & Nisbett, 1973), yerbal praise (Deci, Cascio, &
685 citations
TL;DR: In this article, the authors develop a theory of market segmentation based on consumer self-selection and show that this relaxation has significant implications for how the products and prices are chosen and what they look like.
Abstract: The purpose of this paper is to develop a theory of market segmentation based on consumer self-selection. The extant theory is based on the third-degree price discrimination model of Pigou, central assumptions of which are that the firm can directly address individual segments and isolate them. By using consumer self-selection, I am relaxing these assumptions. In the context of a monopolist designing a product line, I show that this relaxation has significant implications for how the products and prices are chosen and what they look like. In particular, segments may be aggregated even though there are no economies of scale. Furthermore, consumer self-selection enables us to model “cannibalization” and competition among firms.
676 citations
TL;DR: The results suggest that dihydropyridines bind preferentially to the inactivated state of the calcium channel, and that the development of usedependent block is related to the ionization constants of the compounds.
Abstract: We have investigated the mechanisms of blockade of calcium channel current by the dihydropyridines, e.g. nisoldipine, nitrendipine, and nicardipine. Membrane current was recorded in isolated calf Purkinje fibers using a two-microelectrode voltage-clamp technique, and voltage protocols were designed to identify voltage- and use-dependent block by these compounds systematically. Our results show that calcium channel blockade by dihydropyridine derivatives is strongly modulated by membrane potential. Block is more pronounced when current is measured from depolarized holding potentials, but in contrast to verapamil, this voltage-dependent block occurs in the absence of repetitive depolarizations. Use-dependent block by dihydropyridines is observed at pulse frequencies greater than 1 Hz. Our results suggest that dihydropyridines bind preferentially to the inactivated state of the calcium channel, and that the development of use-dependent block is related to the ionization constants of the compounds. Furthermore, binding is approximately one thousand times stronger to inactivated channels than to resting channels. This state-dependent difference in binding affinities may account for the previously reported contrast between electrophysiological and binding data for these compounds.
544 citations
TL;DR: In this article, a nonlinear stochastic process is presented that reproduces Luder's projection postulate, and the corresponding density operator undergoes a linear evolution reproducing von Neumann's projection.
Abstract: A nonlinear stochastic process is presented that, for each realization and for large times, reproduces L\"uder's projection postulate. The corresponding density operator undergoes a linear evolution reproducing von Neumann's projection postulate. The violation of the Bell inequality, for instance, is described with the two apparatus acting independently on the composed system.
442 citations
TL;DR: The records of all patients with abdominal aortic aneurysms in a Midwest city with a stable population over a 30-year period were reviewed, revealing an absolute increase in the incidence of AAAs in the population under study and the frequency of rupture was greatest in the last decade.
426 citations
TL;DR: The physical properties and mode of replication of HSV are briefly described, and an outline of the different clinical manifestations associated with HSV infection is presented.
Abstract: Infections with herpes simplex virus (HSV) are extremely common. HSV infection may be asymptomatic or may cause any one of a wide variety of disease syndromes. In this review, the physical properties and mode of replication of HSV are briefly described, and an outline of the different clinical manifestations associated with HSV infection is presented. Principles of diagnosis, treatment, and prevention of these infections are also discussed.
TL;DR: Differences between abused, neglected, and comparison children were present on a number of measures, indicating that maltreated children display significant cognitive and social deficits.
Abstract: 42 preschool children who had a previous history of physical abuse, serious neglect, or no prior history of child maltreatment participated in a multimodal assessment of cognitive and behavioral functioning. In addition to standardized tests of cognitive ability and behavioral observations in the classrooms, both the parents and teachers rated the children on several measures. Results show that the abused and neglected children had lower scores on all the measures of cognitive functioning when compared to the matched comparison children. The behavioral observation data from the classrooms, however, were more complex. That is, differences among groups depended on the type of behavior observed. Neglected children engaged in the least number of interactions with other children, and the abused children demonstrated the most aggression. Both parents and teachers rated the maltreated children as more aggressive, less mature, and less ready to learn. In summary, differences between abused, neglected, and comparison children were present on a number of measures, indicating that maltreated children display significant cognitive and social deficits.
TL;DR: It is proposed that chromatin assembly is an active, ATP-driven process that catalyzes DNA supercoiling and Chromatin assembly in vitro.
TL;DR: In this article, the deepinelastic electron-scattering cross sections per nucleon were measured in the kinematic range $0.09l~xl~0.9$ and $2l~{Q}^{2}l~15$ with use of electrons with energies ranging from 8 to 24.
Abstract: The deep-inelastic electron-scattering cross sections per nucleon ${\ensuremath{\sigma}}_{A}$ for D, He, Be, C, A1, Ca, Fe, Ag, and Au were measured in the kinematic range $0.09l~xl~0.9$ and $2l~{Q}^{2}l~15$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^{2}$ with use of electrons with energies ranging from 8 to 24.5 GeV. The ratio $\frac{{\ensuremath{\sigma}}_{A}}{{\ensuremath{\sigma}}_{\mathrm{D}}}$ is consistent with unity in the range $0.1lxl0.3$. For $0.3lxl0.8$, the ratio decreases logarithmically with atomic weight $A$, or linearly with average nuclear density. No ${Q}^{2}$ dependence in the ratio was observed over the kinematic range of the data.
TL;DR: This work states that generalized Recombination, followed by Gyrase-Mediated Illegitimate Recombinations, and then Topoisomerases, Recombination, and RePAIR are viable strategies for DNA replication.
TL;DR: In this article, the problem of population inversion adiabatically in an $N$-level system using one or more laser fields whose detunings and/or amplitudes are continuously varied is studied analytically and numerically.
Abstract: The problem of achieving population inversion adiabatically in an $N$-level system using one or more laser fields whose detunings and/or amplitudes are continuously varied is studied analytically and numerically. The $\mathrm{SU}(N)$ coherence vector picture is shown to suggest unexpected inversion procedures and also to give a generalized interpretation of adiabatic following. It is shown that the (${N}^{2}\ensuremath{-}1$)-dimensional $\mathrm{SU}(N)$ space contains an ($N\ensuremath{-}1$)--dimensional steady-state subspace $\mathit{\ensuremath{\Gamma}}(t)$ whose orthonormal basis vectors ${\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\Gamma}}}_{1},\dots{}, {\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\Gamma}}}_{N\ensuremath{-}1}$ are given explicitly in terms of the Hamiltonian matrix elements. The motion of the system can be interpreted as a "generalized precession" of $\stackrel{\ensuremath{\rightarrow}}{\mathrm{S}}$ about $\mathit{\ensuremath{\Gamma}}$. Multilevel adiabatic following occurs when the angle $\ensuremath{\chi}(t)$ between the coherence vector $\stackrel{\ensuremath{\rightarrow}}{\mathrm{S}}$ and its projection onto $\mathit{\ensuremath{\Gamma}}$ is very small. The multiple dimension of $\mathit{\ensuremath{\Gamma}}$ is shown to provide a variety of paths for adiabatic inversion. The adiabatic solution is obtained by solving $N\ensuremath{-}1$ simple equations for the directional cosines of $\stackrel{\ensuremath{\rightarrow}}{\mathrm{S}}$ on ${\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\Gamma}}}_{i}$. The adiabatic solution and time scale and the state taken up by the atomic variable are discussed analytically and numerically for a three-level system.
TL;DR: The mid-Paleozoic radiation of durophages and response of the marine fauna was in many respects similar to events of the Mesozoic Marine Revolution, in effect, the Paleozoic precursor to that event.
Abstract: The mid-Paleozoic was punctuated by a rapid radiation of durophagous (shell-crushing) pred- ators. These new predators were primarily placoderm and chondrichthyan fishes but probably also included phyllocarid and eumalacostracan arthropods. Coincident with the radiation of these durophages, beginning in the mid-Devonian, there was an increase in the frequency of predation-resistant morphologies in a variety of marine invertebrate taxa. Among bellerophontid molluscs, disjunct coiling disappeared and umbilici became less common while the frequency of genera with sculpture increased. The abundance of brachiopod genera with spines on one or both valves increased dramatically. Sculpture became more pronounced and common among genera of coiled nautiloids. Inadunate and camerate crinoids showed a marked increase in spinosity, and all three crinoid subclasses tended to develop thicker thecal plates. Trends toward increasing relative frequencies of predation-resistant features were formed in different ways. Bellerophontid genera lacking predation-resistant features tended to go extinct, leaving the sculp- tured, tightly coiled forms as the predominant forms. Among Brachiopoda, the radiation of productids provided the tremendous increase in numbers of spinose genera. Among crinoids, predation-resistant features were acquired through evolution within established clades. These observations suggest that predation by shell-crushing predators has been an important control on the morphology and composition of the marine invertebrate fauna since at least the Middle Devonian. The mid-Paleozoic radiation of durophages and response of the marine fauna was in many respects similar to events of the Mesozoic Marine Revolution, in effect, the Paleozoic precursor to that event.
TL;DR: The authors compare des relations mere-enfant par une observation dans le milieu naturel: moins de comportements positifs and plus de concortements agressifs chez la mere maltraitante et chez l'enfant maltraite, minimum d'interactions chez les meres negligentes.
Abstract: Comparaison des relations mere-enfant par une observation dans le milieu naturel: moins de comportements positifs et plus de comportements agressifs chez la mere maltraitante et chez l'enfant maltraite, minimum d'interactions chez les meres negligentes
TL;DR: G prognostic information on recurrence and survival for resected Stage I lung cancer patients with squamous cell carcinoma, adenocarcinoma or large cell carcinomas is presented.
Abstract: The authors present prognostic information on recurrence and survival for resected Stage I lung cancer patients with squamous cell carcinoma, adenocarcinoma or large cell carcinoma. The data derive from 392 carefully staged patients and include results from the history and physical examination, preoperative laboratory tests, nature of the surgery, complications, initial pathologic findings following surgical resection, and final pathologic review. A simple multivariate model of recurrence, which is used to classify patients into low, intermediate, and high-risk groups, is based on tumor size and location (T1, T2), histologic type (squamous, nonsquamous/mixed) and nodal status (N0, N1). To model survival, the performance status and the presence of empyema, pneumonia, or wound infection were added to the previous factors. Not all factors associated with increased mortality are associated with increased risk of recurrence, and, in particular, postoperative empyema, pneumonia or wound infections carry an increased risk of death only. Serial measurements of performance status and leukocyte count have the potential for monitoring for increased risk of recurrence and death.
TL;DR: Two new shuttle vectors have been constructed by fusing the Escherichia coli plasmid pUC9 with the Staphylococcus aureus plasmids pU110 and pC194, which replicate in both E. coli and Bacillus subtilis and contain seven restriction sites within a part of the lacZ gene.
TL;DR: The results are interpreted as evidence that inactivation is both voltage and Ca dependent, and that the rate of in activation is increased as Ca enters during depolarizing pulses, perhaps because of an additional Ca-dependent mechanism.
Abstract: We have studied the influence of divalent cations on Ca channel current in the calf cardiac Purkinje fiber to determine whether this current inactivates by voltage- or Ca-mediated mechanisms, or by a combination of the two. We measured the reversal (or zero current) potential of the current when Ba, Sr, or Ca were the permeant divalent cations and determined that depletion of charge carrier does not account for time-dependent relaxation of Ca channel current in these preparations. Inactivation of Ca channel current persists when Ba or Sr replaces Ca as the permeant divalent cation, but the voltage dependence of the rate of inactivation is markedly changed. This effect cannot be explained by changes in external surface charge. Instead, we interpret the results as evidence that inactivation is both voltage and Ca dependent. Inactivation of Sr or Ba currents reflects a voltage-dependent process. When Ca is the divalent charge carrier, an additional effect is observed: the rate of inactivation is increased as Ca enters during depolarizing pulses, perhaps because of an additional Ca-dependent mechanism.
TL;DR: Root surfaces that had received acid treatment after root planing exhibited funnel-shaped orifices of dentinal tubules, and intertubular zones with a fibrillar, mat-like morphology, compared with those that had been treated with citric acid alone.
Abstract: The purpose of this study was to characterize, using the scanning electron microscope, the nature of root surfaces denuded by (1) root planing alone or (2) root planing plus citric acid treatment. Six teeth were extracted from three squirrel monkeys, and the coronal half of the root surface was planed to remove attached periodontal ligament fibers and cementum. Citric acid, pH 1, was topically applied to the denuded surfaces of 3 teeth. The surface of only root-planed specimens had an irregular surface which corresponded to a smear layer. Root surfaces that had received acid treatment after root planing exhibited funnel-shaped orifices of dentinal tubules, and intertubular zones with a fibrillar, mat-like morphology. The implications of the different root-surface characteristics are discussed.
TL;DR: Findings for K1 isolates add to a growing body of evidence supporting the hypothesis that the genetic structure of natural populations of E. coli is basically clonal, with very limited recombination of chromosomal genes.
Abstract: Genotypes of 142 K1 isolates of four O serogroups of Escherichia coli from human hosts in Europe and the United States were characterized by an electrophoretic analysis of allozymic variation in 12 chromosomally encoded enzymes. The genetic structure of natural populations revealed by this analysis is closely similar to that indicated in earlier studies by Achtman and colleagues of the electrophoretic migration pattern for four outer membrane proteins and the chemical structure of the cell-wall lipopolysaccharides. The combined evidence demonstrates that most of the K1 isolates belong to a small number of geographically widespread clones. The distribution of O serogroups among the isolates does not consistently correspond to the clonal structure; O1:K1 isolates represent at least two distantly related, geographically widespread clones, one of which is genetically similar to a clone of the O18:K1 serotype. These findings for K1 isolates add to a growing body of evidence supporting the hypothesis that the genetic structure of natural populations of E. coli is basically clonal, with very limited recombination of chromosomal genes. Clonal structure has important implications for the study of the determinants of pathogenicity and disease specificity in E. coli.
TL;DR: It is found that plasmids isolated from bacteria grown at different temperatures exhibit differences in DNA linking numbers, which are consistent with the hypothesis that fine control of DNA topology in bacterial cells is brought about by changes in linking number to maintain a constant value for supercoiling.
Abstract: The level of DNA supercoiling can be altered either by breaking-rejoining reactions that change the DNA linking number or by environmental changes that alter the helical pitch of DNA. In vitro, temperature changes alter helical pitch and, thus, supercoiling. We find that plasmids isolated from bacteria grown at different temperatures exhibit differences in DNA linking numbers. The differences in plasmid linking numbers offset the effect temperature is expected to have on supercoiling. These results are consistent with the hypothesis that fine control of DNA topology in bacterial cells is brought about by changes in linking number to maintain a constant value for supercoiling.
TL;DR: In this article, qualitative and quantitative arguments are presented that elucidate the modifications that the whole three-dimensional structure of the diffracted field undergoes as the Fresnel number is gradually decreased, and contours of equal intensity in the focal region are presented for systems of selected Fresnel numbers, which focus uniform waves.
Abstract: It was recently shown that, when a converging spherical wave is focused in a diffraction-limited system of sufficiently low Fresnel numbers, the point of maximum intensity does not coincide with the geometrical focus but is located closer to the exit pupil. In the present paper both qualitative and quantitative arguments are presented that elucidate the modifications that the whole three-dimensional structure of the diffracted field undergoes as the Fresnel number is gradually decreased. Contours of equal intensity in the focal region are presented for systems of selected Fresnel numbers, which focus uniform waves.
TL;DR: One hundred eighty cases of Meniere's disease were identified in the Rochester, MN population during the 30‐year period, 1951 through 1980, and the annual age‐adjusted incidence rate was 15.3; the preponderance for females over males was not statistically significant.
Abstract: One hundred eighty cases of Meniere's disease were identified in the Rochester, MN population during the 30-year period, 1951 through 1980. The annual age-adjusted incidence rate per 100,000 population was 15.3; the preponderance for females (16.3) over males (13.3) was not statistically significant. There was no change in annual incidence rate from 1951 through 1970, and a slight decrease in the period, 1971 through 1980. The prevalence rate on January 1, 1980, was 218.2 per 100,000 population. Clinical aspects of Meniere's disease noted during the course of this study are reported.
TL;DR: Stage for stage, the prognosis of patients with adenocarcinoma of the small intestine parallels that of patientsWith greater awareness of this tumor, it is possible that earlier detection will lead to improved overall survival.
Abstract: Sixty-five patients with adenocarcinoma of the small intestine were encountered over a 31 year period. The duodenum was the most common location, with a decreasing frequency distally. Associated malignancies were present in a fourth of the patients. Presenting signs and symptoms were vague and related to either obstruction or bleeding. Barium contrast examination and endoscopy for duodenal tumors were the primary diagnostic modalities. Curative treatment was wide resection of bowel and mesentery for jejunal and ileal tumors and pancreaticoduodenectomy for duodenal tumors. Favorable prognosticators included jejunal location, absence of nodal metastases, and a well-differentiated grade. Stage for stage, the prognosis of patients with adenocarcinoma of the small intestine parallels that of patients with adenocarcinoma of the colon. With greater awareness of this tumor, it is possible that earlier detection will lead to improved overall survival.
TL;DR: La base des modifications provoquees par les radiations est liee a l'hypoplasie parenchymateuse cellulaire des cellules souches et aux modifications avec vaisseaux fins et des tissus fibro-conjonctifs.
Abstract: La base des modifications provoquees par les radiations est liee a l'hypoplasie parenchymateuse cellulaire des cellules souches et aux modifications avec vaisseaux fins et des tissus fibro-conjonctifs. Les effets tardifs de la chimiotherapie resulteraient principalement de la depletion parenchymateuse cellulaire de cellules non en mitoses et en mitoses mais avec une epargne de la microcirculation et du strome des tissus fibroconjonctifs
TL;DR: It is suggested that an association between RSV lower respiratory tract infections and chronic abnormalities of pulmonary function may be detected sequentially through the first 8 years of life, not limited to those children developing an atopic state during that same time period.