Showing papers by "University of Houston published in 1973"

War and the Birth of the Nation State

Abstract: The rise of the nation-state is assigned by most historians a central role in the economic growth of Europe. Most recently Douglass North and Robert Thomas have argued that sustained economic growth was made possible only by institutional changes which, themselves, were a consequence of the rise of the nationstate. Thus it is clear that a complete model of the economic growth of Europe will have to account for the rise of the nation-state. That is.the humble task of this paper.

Porphyrins XXVIII. Extended Hückel calculations on metal phthalocyanines and tetrazaporphins

Abstract: Extended Huckel (EH) calculations on Mg, Zn, Cu, Ni, Fe, Mn, and VO complexes of phthalocyanine and tetrazaporphin are reported and the results compared to similar calculations on porphyrins The smaller ring size of phthalocyanine gives rise to a larger ligand field The bridge nitrogen atoms give rise to n - π * transitions, which are probably in the region of the Soret band In Ni, Co, Fe, and Mn there is strong mixing of the bridge N2p σ and metal b 2g (d xy ), which should affect the ligand field Extra absorption bands observed in the near uv of NiPc and CoPc are attributed to d π → π * transitions A general symmetrized EH program is reported that speeds calculations on large systems

Concentration and analysis of trace volatile organics in gases and biological fluids with a new solid adsorbent

Abstract: A new procedure for sampling, transfer, and analysis of volatile organic compounds by gas chromatography has been developed. An adsorbent trap ultimately becomes an insert for a modified injector port, and a valve system allows the sample to be transferred to a cooled precolumn and finally to the separating column. Several traps may be used for sampling (for multiple injections), and it has been established that such traps may be stored without loss of sample. The ease and reproducibility of this procedure is amenable for the investigation of volatile organic compounds involving air and water pollution, flavor, and aroma analyses, and body fluid metabolites.

Profile of volatile metabolites in urine by gas chromatography-mass spectrometry.

Abstract: Profiles of volatile metabolites of 150 urine samples from normal individuals and 40 samples from subjects with diabetes mellitus have been studied by gas chromatography and mass spectrometry. The technique involves adsorption of the urinary headspace volatiles on Tenax GC, heat desorption with helium, trapping on a cooled precolumn, and chromatography on 100-m X 0.50-mm i.d. nickel columns. Individual profiles were observed over a period of 2 months. Characteristic constituents in normal urines are 2-butanone, 2-pentanone, 4-heptanone, dimethyl disulfide, several alkyl furans, pyrrole, and carvone. In subjects with diabetes mellitus under insulin treatment, high concentrations of pyrazines, cyclohexanone, lower aliphatic alcohols, and octanols were found.

Contribution of the crystalline lens to the spherical aberration of the eye

Abstract: The influence of the corneal shape on the quality of the retinal image has been studied. We have distinguished between the role of the cornea and that of the crystalline lens; the wave surface behind the cornea was determined. First, the corneal topology was measured by photographic keratometry. Then, for the same subject, the spherical aberration of the eye was determined by the Foucault knife-edge test. The shapes of the anterior and posterior surfaces of the crystalline lens have been determined from experimental data.

Rheological behavior of shear degradable oils: Kinetic and equilibrium properties

Abstract: An investigation of the non-Newtonian, time dependent, flow properties of various crude oils at or below their pour points is reported. Experimental observations of material response under various shear and stress conditions provide a basis for the development of a kinetic and rheological model which quantitatively describes the shear degradation and equilibrium behavior exhibited by these materials. Preliminary data on the effects of thermal history and aging are also reported, showing the relative importance of these factors to the rheological properties. On presente une etude des proprietes d'ecoulement (nonnewtonien et dependant du temps) de diverses huiles brutes, a leurs points de fluidite ou au-dessous de ceux-ci. Les observations experimentales de la reponse des huiles dans diverses conditions de cisaillement et de tension ont fourni les elements de base pour la mise au point d'un modele cinetique et rheologique qui decit quantitativement la degradation par cisaillement et le comportement d'equilibre manifeste par les huiles. On rapporte aussi les resultars preliminaires qu'on a obtenus sur les effets de la chaleur et du vieillissement; ils montrent l'importance relative de ces facteurs sur les proprietes rheologiques.

In vitro fertilization with non-motile spermatozoa of the brown shrimp Penaeus aztecus

Abstract: The sperm of the brown shrimp Penaeus aztecus are nonflagellated and non-motile. In vitro fertilization can be obtained when mature eggs removed from female shrimp are added to dense sperm suspensions in seawater and agitated in a manner simulating natural spawning.

Effects of norepinephrine and sympathetic stimulation on extraction of oxygen and 86Rb in perfused canine small bowel.

Abstract: Previous studies have shown that sympathetic stimulation can cause a redistribution of intestinal capillary blood flow. Our computer model of the intestinal circulation predicted that the diffusion parameters (e.g., capillary surface area and mean capillaryto-cell diffusion distance) altered by precapillary sphincter closure would be sufficient to affect intestinal oxygen extraction. To test this prediction in an animal model, we made continuous measurements of arteriovenous oxygen difference (ΔO 2 ) and perfusion pressure during constant-flow perfusion of isolated loops of canine small bowel. Intraarterial infusion of norepinephrine or stimulation of sympathetic nerves for 7 minutes produced sustained increases in vascular resistance and sustained reductions in arteriovenous ΔO 2 . Maximal changes in resistance and arteriovenous ΔO 2 occurred by the second minute of norepinephrine or sympathetic nerve stimulation, and subsequently both parameters escaped somewhat. The maximal and steady-state values of these parameters were dose-dependent or frequency-dependent. In other experiments, sympathetic nerve stimulation caused synchronous decreases in arteriovenous ΔO 2 and 86 Rb extraction. These results support the hypothesis that the infusion of norepinephrine and the stimulation of sympathetic nerves cause sustained reductions in the density of the perfused capillary bed which are sufficient to reduce intestinal extraction of Rb and oxygen despite constant-flow perfusion.

A computational method for eigenvalues and eigenvectors of a matrix with real eigenvalues

Abstract: This paper describes a new computational procedure for calculating eigenvalues and eigenvectors of a square matrix. The method is based on a matrix function, the sign of a matrix. Eigenvalues and eigenvectors of matrices with distinct eigenvalues and nondefective matrices with repeated roots can be determined in a straightforward manner. Defective matrices require additional calculations.

Steady state multiplicity and stability of enzymatic reaction systems.

Abstract: Several techniques for investigating the multiplicity and stability of open isothermal enzymatic reactors are discussed and some of the pitfalls in previous thinking pointed out. The example which is used to illustrate these methods exhibits several interesting features. Among these is the existence of a stable oscillatory state which surrounds a unique steady state which is asymptotically stable to certain finite disturbances.

Studies on the tardigrades. II. Fine structure of the pharynx of Milnesium tardigradum Doyère.

Abstract: The fine structure of the pharynx and associated valve of the tardigrade Milnesium tardigradum is presented. The pharynx consists of a triradiate, cuticle lined lumen surrounded by radially arranged muscle cells and special apical cells which cap each of the ventricles of the lumen. The valve is an unusual structure marking the anterior limit of the pharynx. It is a specialization of the cuticular lining of the foregut and the apical cells of the pharynx. The significance and phyletic affinities of these structures are discussed.

An Iterative Approach to the Feature Selection Problem

Abstract: The problem dealt with concerns feature selection or reducing the dimension of the data to be processed from n to k. By reducing the dimension of the data from n to k, classification time is generally reduced. Yet the dimension reduction should not be so great that classification accuracy is impaired. Thus, the general problem is considered of classifying an n-dimensional observation vector x into one of m-distinct classes where each class is normally distributed with mean and covariance. It is shown that the probability of misclassification is minimized if a maximum likelihood classification procedure is used to classify the data. The dimension of each observation vector to be processed is conveniently reduced by performing the transformation y = Bx, where B is a K by n matrix of rank k. Thus, the n-dimensional classification problem transforms into a k-dimensional classification problem.

Studies on the tardigrades. I. Fine structure of the anterior foregut of Milnesium tardigradum Doyère.

Abstract: The fine structure of the anterior foregut of the tardigrade Milnesium tardigradum is presented. The oral region consists of a terminal mouth opening surrounded by six plate-like lips lying within a circlet of six prominent papillae. The buccal cavity is enclosed within a thick cuticular tube which possesses appendage structures, the stylet sheaths, stylet supports and paired protrusible stylets. Two large salivary glands envelop the buccal structures and contain voluminous amounts of secretory product. The arrangement, possible functions and phyletic significance of these structures are discussed.

Toward a Contingency Theory of Organizational Control

Abstract: The association between three organizational control variables and measures of effectiveness is examined. The findings indicate that organizational performance at the first level of management is e...

Application of dicarbonyl-rhodium-trifluoroacetyl-d-camphorate to special problems of olefin analysis by gas-liquid chromatography

Abstract: The title compound, dissolved in squalane, has been used as stationary phase in g.l.c. for purity determinations of olefins. High resolution open tubular columns have been prepared with the same phase. C2H4, C2D4 and the isomeric butenes were efficiently separated.

Sedimentation and intrinsic viscosity behavior of PM2 bacteriophage DNA in alkaline solution

Abstract: The sedimentation coefficient and intrinsic viscosity of nicked and closed circular PM2 bacteriophage DNA have been measured as a function of pH in the alkaline region. A gradual increase in the sidimentation coefficient, and a corresponding decrease in the intrinsic viscosity, are observed for the superhelical (closed) circle in the pH region from 10.5 to about 10.9. This has been tentatively interpreted in terms of the known dependence of sedimentation coefficient upon the number of superhelical turns. At slightly higher pH values, the curve passes through the minimum (sedimentation coefficient) and maximum (intrinsic viscosity) expected when the superhelical turns present at neutral pH are unwound by partial alkaline denaturation. Sedimentation studies of the relaxed (nicked) circular species have revealed the existence of DNA forms in the pH region from 11.27 to 11.37 which sediment considerably faster than the closed circle in the same pH region. These have been identified as partially denatured nicked circles, in which varying fractions of the duplex structure have undergone alkaline denaturation, but strand separation has not yet occurred. Varying fractions of a slower species, either undenatured or completely denatured nicked circles, are also observed in some of these experiments. A corresponding result is observed in the intrinsic viscosity vs. pH curve. When nicked circular PM2 DNA is exposed to various alkaline pH's, rapidly neutralized, and sedimented at neutral pH, the expected sharp transition from native to denatured (strand-separated) molecules is seen. However, a very narrow pH range is noted in which native and denatured forms coexist in a single experiment. The above experiments carried out upon the closed form also reveal a narrow pH range in which the bulk of the transition from native closed circles to the collapsed cyclic coil takes place, in acccord with an earlier study on a different DNA. This transition is shown never to be completely effected, however, as there is a fraction (7–8%)of the closed circles which renature to the native form, regardless of the alkaline pH employed. This same phenomenon was not observed in the case of artificially closed λb2b5c DNA circles. Possible explanations for some of the above results are discussed.

New theorems of association of variables in multiple dimensional Laplace transform

Abstract: In non-linear systems analysis, multiple dimensional Laplace transform is often applied in solving the volterra model. The special technique for the inverse Laplace transform solution is called the association of variables. Three new thoorems are developed for the theory of association. Compared with the inspection method of Brilliant, the pair listing method of Lubbock, the new approach is much simpler and easier and more systematic. Several illustrative examples are included.

Charge and energy spectra of trans-iron cosmic rays

Abstract: A 22-${\mathrm{m}}^{2}$ detector array consisting of $G\ensuremath{-}5$ nuclear emulsion, fast-film \ifmmode \check{C}\else \v{C}\fi{}erenkov detector, and 40 sheets of plastic detectors was exposed for \ensuremath{\sim} 60 h at a mean atmospheric depth of \ensuremath{\sim}3.7 g/${\mathrm{cm}}^{2}$ and a rigidity of 2.5 GV. The detector was designed to determine both the charge and energy of trans-iron nuclei. For the first time it has been possible to determine cosmic-ray abundances in the difficult region $30Z\ensuremath{\le}42$ as well as to study the heavier nuclei. Over the entire periodic table from Ne on, the trend of cosmic-ray abundances is similar to that expected from sources with solar abundances, after nuclear reactions in interstellar space have been taken into account. The abundance ratios $[Z\ensuremath{\ge}90]:[81\ensuremath{\le}Z\ensuremath{\le}83]:[74\ensuremath{\le}Z\ensuremath{\le}80]$ are not inconsistent with solar abundances if Grevesse's photospheric abundances of Th and U, adjusted for radioactive decay, are adopted instead of meteoritic abundances. These ratios agree somewhat better with an $r$-process composition and a leakage lifetime of several million years. No trans-uranic nuclei were observed in the present flight. Serious consideration must be given to the possibility that most of the cosmic rays with $Z60$ originate from material of solar composition. One of the major new results of the study was the determination of an energy spectrum for the nuclei with $Z60$. If the integral-energy spectrum is given by $N(E)\ensuremath{\propto}{(E+{M}_{0}{c}^{2})}^{\ensuremath{-}\ensuremath{\eta}}$ where $E$ is the kinetic energy per nucleon, then the spectral index for high-$Z$ nuclei is $\ensuremath{\eta}=2.75\ifmmode\pm\else\textpm\fi{}0.53$ for $0.5 \frac{\mathrm{GeV}}{\mathrm{amu}}\ensuremath{\le}E\ensuremath{\le}2.0 \frac{\mathrm{GeV}}{\mathrm{amu}}$. In the same energy interval the index for helium nuclei is $\ensuremath{\eta}=1.3$. This may imply a different origin for high- and low-$Z$ cosmic rays.