Showing papers by "Bar-Ilan University published in 1982"

Intracellular oxidation-reduction state measured in situ by a multichannel fiber-optic surface fluorometer

Abstract: The principles of the measurement in vivo of the oxidation-reduction state of intramitochrondrial pyridine nucleotides were used in establishing a multichannel fluorometer-reflectometer. This approach made possible the study of changes of mitochrondrial redox states in four different organs (brain, liver, kidney, and testis) of the same animal, as well as the monitoring of four different cortical areas of the same brain hemisphere. In the measurement of reduced nicotinamide adenine dinucleotide fluorescence, oximetric and movement artifacts are negligible, but blood volume changes and tissue absorption properties are a source of error. The corrected fluorescence is obtained by subtracting the reflectance from the fluorescence signed in 1:1 ratio., During graded hypoxia, the corrected fluorescence showed a gradual increase and was maximal during anoxia in all four organs tested.

The complexity of finding maximum disjoint paths with length constraints

Abstract: The following problem is considered: Given an integer K, a graph G with two distinct vertices s and t, find the maximum number of disjoint paths of length K from s to t. The problem has several variants: the paths may be vertex-disjoint or edge-disjoint, the lengths of the paths may be equal to K or bounded by K, the graph may be undirected or directed. It is shown that except for small values of K all the problems are NP-complete. Assuming P ≠ NP, for each problem, the largest value of K for which the problem is not NP-complete is found. Whenever a polynomial algorithm exists, an efficient algorithm is described.

A Shifting Algorithm for Min-Max Tree Partitioning

Abstract: The problem of finding a mm-max partmon of a weJghted tree T with n veruces into q subtrees by means of k = q 1 cuts is considered. A top-down shifting algorithm for this problem ts presented An outhne is given of an efficJent implementatmn of the algorithm wtth complexity O(k3rd(T) + kn), where rd(T) ts the number of edges m the radius of T

A comparison of nine systems to diagnose schizophrenia.

Abstract: The files of 283 hospitalized patients discharged with a diagnosis of schizophrenia, schizoaffective schizophrenia, or paranoid state were examined without knowledge of the patient's subsequent history. These patients, most of whom had originally been diagnosed by DSM-I criteria, were retrospectively diagnosed by New York Research Diagnostic Criteria (RDC), the New Haven Schizophrenia Index (NHSI), the St. Louis criteria, Taylor-Abrams 1978 criteria, Schneider's first-rank symptoms (FRS), the Washington IPSS 12-Point Flexible System, Astrup's process/nonprocess distinction, and DSM-III . Kappa values measuring pairwise diagnostic agreement among the nine systems were typically low except among RDC, DSM-III , and St. Louis criteria. Long-term followup status was not significantly predicted by the FRS, NHSI, or Taylor-Abrams criteria. Diagnosis by means of the other systems, especially the Astrup process/ nonprocess distinction, was significantly correlated with followup. However, Astrup's "process" schizophrenia is not operationally defined and could not be expected to be used with the degree of interrater reliability desired by researchers. On the other hand, of the operationally defined systems, DSM-III schizophrenia has the highest correlation with followup and is thus suggested for use by researchers desiring a highly homogenous, although narrowly defined, population. Investigators wishing to cast a wider net could use a less restrictive system such as the RDC, with or without schizoaffectives included.

Stem rust of wheat 3300 years old found in Israel.

Abstract: A fungus parasite observed on two ancient lemma fragments of wheat was identified as Puccinia graminis. The fragments were found in a storage jar from the Late Bronze Age excavated at Tel Batash, Israel, Uredia, hyphae, and germinating uredospores, though charred, were well preserved.

Intuitonistic Basis for Non-Monotonic Logic

Abstract: McDermott and Doyle [4] suggested a system, denoted by ⊢, of non-monotonic logic. This notion was intended to formalise non-monotonic reasoning as involved in real situations and in artificial intelligence. McDermott and Doyle also list in their paper several difficulties and problems in their approach. Their semantics seems to be inadequate and there are several counterintuitive results obtained in their system.

Characterization of Mg2+- and Ca2+-ATPase activity in membrane vesicles from ejaculated ram seminal plasma

Abstract: The activity of divalent cation-stimulated adenosine triphosphatase (ATPase) has been studied in vesicular membranes isolated from ejaculated ram seminal plasma. This nonspecific acidic ATPase can be activated by millimolar concentration of any one of the following cations: Ca2+, Mg2+, Zn2+, or Mn2+ to give high specific activity (approximately 300 mumol/mg/hr), in absence of the other cations. Free Zn2+ inhibits activity of this ATPase. The Km for adenosonine triphosphate (ATP) ranged between 0.17 and 0.24 mM, and for the divalent cation ranged between 0.4 and 0.8 mM. When the ATPase is activated by Ca2+, two Kms for Ca2+ concentration were found: 0.8 and 0.08 mM. It is suggested that the seminal plasma membranes also contain alkaline ATPase, which is more specific for Ca2+.

Mutual Perceptions of Arabs and Jews in Israel

Abstract: Mutual perceptions of Israeli Arabs and Jews were examined; 132 Jewish university students and 122 Arab teacher college students rated the social and intellectual characteristics of a typical Israeli Arab and a typical Israeli Jew on a semantic differential scale. The findings showed that (1) each group views itself more favorably that it does the other; (2) both groups agree that the Jew excels intellectually rather than socially, while the opposite holds true for the Arab; and (3) the Jews emphasize their intellectual advantage, while the Arabs emphasize their social superiority. The results were related to other findings indicating that these perceptions are part of more general image, common in Israel, of Western and Middle-Eastern persons.

Optimum Contracts for Research Personnel, Research Employment, and the Establishment of

Abstract: This paper considers the problem of hiring scientists for research and development projects when one takes explicit account of the fact that the scientist may be able to use the information acquired during the project in a rival enterprise Management's problem is to determine an optimum labor policy for its project The policy consists of an employment decision and a labor contract Given optimum behavior, it is straightforward to analyze the effect of the potential for mobility of scientific personnel on project profitability and on research employment We also formalize conditions under which one would expect to observe a scientist leaving his employer to set up (or join) a rival

Non-Immunological Recognition and Killing of Xenogeneic Cells by Macrophages: III Destruction of Fish Cells by Murine Macrophages

Abstract: Non-immune non-activated murine peritoneal macrophages killed in vitro fish ( Cyprinus carpio ) PHA-induced lymphoblasts. Addition of PHA and WGA to effector-target cell cultures did not potentiate the killing. This killing (xenolysis) was expressed by non-elicited and thioglycollate-elicited macrophages as well as by macrophages depleted of lymphocytes. It is suggested that mammalian macrophages have a xenolytic potential towards phylogenetically distant species which is analogous to the capacity of invertebrate phagocytes to destroy xenografts.

Ultrastructural studies in Morphological assessment of human spermatozoa

Abstract: The fine morphology of the regional structure of ejaculated spermatozoa which was observed by light microscope, scanning electron microscope and transmission electron microscope was the basis for the classification of various morphological characteristics. A quantitative analysis of the frequencies of these morphological characteristics in the fertile and suspected infertile populations was conducted. A discriminant analysis of these data revealed that 6 morphological characteristics out of 30 examined by light microscope, 9 out of 42 examined by scanning electron microscope and 8 out of 35 examined by transmission electron microscope were discriminatory. In addition, the discriminant analysis enabled obtaining a morphological score for each semen sample which was calculated from the weights of the different discriminatory characteristics for the 3 microscopic techniques. It was possible to separate the fertile from the infertile population using these morphological scores. The fertile man obtained positive scores while the suspected infertile men obtained negative scores. The practical use of the different morphological scores as diagnostic tools for male infertility clinics is discussed.

Optimized mixture of sex pheromonal components for trapping of maleSpodoptera littoralis in Israel

Abstract: The sex pheromone gland extracts ofSpodoptera littoralis (Boisd.) in Israel were reexamined by capillary gas chromatography and capillary gas chromatography combined with mass spectrometry. The following compounds were identified: (Z)-9-tetradecenyl acetate (46%), (Z,E)-9,11-tetradecadienyl acetate (33%), (Z,Z)-9,11-tetradecadienyl acetate (4%), (E)-11-tetradecadienyl acetate (9%), (Z)-11-tetradecenyl acetate (7%), and (Z,E)-9,12-tetradecadienyl acetate (0.5-1%). Field tests with various combinations of the major attractant (Z,E)-9,11-tetradecadienyl acetate and the minor components indicated that the best lure forS. littoralis in Israel is 2 mg (Z,E)-9,11-tetradecadienyl acetate containing 0.2-1% of (Z,E)9,12-tetradecadienyl acetate.

Saturation effects in coherent anti-Stokes Raman scattering

Abstract: Saturation effects in coherent anti-Stokes Raman scattering (CARS) spectroscopy are discussed. The discussion is limited to Raman-resonant CARS (${\ensuremath{\omega}}_{l}\ensuremath{-}{\ensuremath{\omega}}_{s}\ensuremath{\simeq}{\ensuremath{\omega}}_{21}$, where ${\ensuremath{\omega}}_{l,s}$ are the frequencies of the pump fields with powers ${P}_{l,s}$, and ${\ensuremath{\omega}}_{21}$ is the frequency of the Raman transition $|1〉\ensuremath{\rightarrow}|2〉$) with the possible addition of a one-photon resonance (${\ensuremath{\omega}}_{l}\ensuremath{\simeq}{\ensuremath{\omega}}_{31}$ is the frequency of the electronic transition $|1〉\ensuremath{\rightarrow}|3〉$). For these cases we show that the CARS polarization ${\mathcal{p}}_{\mathrm{CARS}}$ is proportional to the off-diagonal density-matrix element ${\ensuremath{\rho}}_{21}$. In order to determine ${\ensuremath{\rho}}_{21}$, we use Laplace transforms to solve the Bloch equations for the effective two-level system $|1〉$ and $|2〉$ when ${\ensuremath{\omega}}_{l}$ is far from resonance, or for the three-level system $|1〉,|2〉$, and $|3〉$, when ${\ensuremath{\omega}}_{l}\ensuremath{\simeq}{\ensuremath{\omega}}_{31}$. The steady-state expression for ${\mathcal{p}}_{\mathrm{CARS}}$ in the former case gives ${\mathcal{p}}_{\mathrm{CARS}}\ensuremath{\propto}{P}_{l}{P}_{s}^{\frac{1}{2}}$ at low powers and ${\mathcal{p}}_{\mathrm{CARS}}\ensuremath{\propto}{P}_{l}^{0}{P}_{s}^{\frac{\ensuremath{-}1}{2}}$ at high powers. In the three-level system, we show that when the pressure is low and at least one field is weak, the slow time dependence of ${\ensuremath{\rho}}_{21}$ must be considered. When one field is strong and the other weak, the CARS spectrum is Stark split. When ${P}_{l}$ is high, for example, ${\mathcal{p}}_{\mathrm{CARS}}\ensuremath{\propto}{P}_{l}^{0}{P}_{s}^{\frac{1}{2}}$ for ${\ensuremath{\omega}}_{s}\ensuremath{\simeq}{\ensuremath{\omega}}_{32}$ and ${\mathcal{p}}_{\mathrm{CARS}}\ensuremath{\propto}{({P}_{l}{P}_{s})}^{\frac{1}{2}}$ when ${\ensuremath{\omega}}_{s}\ensuremath{\simeq}{\ensuremath{\omega}}_{32}\ifmmode\pm\else\textpm\fi{}{V}_{13}$ where ${V}_{13}$ is the one-photon Rabi frequency for the $|1〉\ensuremath{\rightarrow}|3〉$ transition. The Wilcox-Lamb approximation is used to reduce the three-level Bloch equations to rate equations containing one- and two-photon terms. When the fields are so weak that both one- and two-photon terms are small compared to the decay terms, the usual expression for ${\mathcal{p}}_{\mathrm{CARS}}$ is reproduced. If only the direct two-photon processes are important, the effective-two-system results are reproduced. When both fields are intense and nearly resonant, the steady state is rapidly achieved. The results for the case where one field is much stronger than the other are essentially the same as those for one strong and one weak field. When the fields are of comparable strength, ${\mathcal{p}}_{\mathrm{CARS}}\ensuremath{\propto}{P}_{l}^{\frac{1}{2}}{P}_{s}^{0}$ for ${\ensuremath{\omega}}_{l}\ensuremath{\simeq}{\ensuremath{\omega}}_{31}$ and ${\ensuremath{\omega}}_{s}\ensuremath{\simeq}{\ensuremath{\omega}}_{32}$, and the CARS spectrum is split into five components.