The bearable lightness of being

How are philosophical questions about what kinds of things there are to be understood and how are they to be answered? This paper defends broadly Fregean answers to these questions. Ontological categories-such as object, property, and relation-are explained in terms of a prior logical categorization of expressions, as singular terms, predicates of varying degree and level, etc. Questions about what kinds of object, property, etc., there are are, on this approach, reduce to questions about truth and logical form: for example, the question whether there are numbers is the question whether there are true atomic statements in which expressions function as singular terms which, if they have reference at all, stand for numbers, and the question whether there are properties of a given type is a question about whether there are meaningful predicates of an appropriate degree and level. This approach is defended against the objection that it must be wrong because makes what there depend on us or our language. Some problems confronting the Fregean approach-including Frege's notorious paradox of the concept horse-are addressed. It is argued that the approach results in a modest and sober deflationary understanding of ontological commitments

Atom in a coherently controlled squeezed vacuum

A broadband squeezed vacuum photon field is characterized by a complex squeezing function. We show that by controlling the wavelength dependence of its phase it is possible to change the dynamics of the atomic polarization interacting with the squeezed vacuum. Such a phase modulation effectively produces a finite range temporal interaction kernel between the two quadratures of the atomic polarization yielding the change in the decay rates as well as the appearance of additional oscillation frequencies. We show that decay rates slower than the spontaneous decay rate can be achieved even for a squeezed bath in the classic regime. For linear and quadratic phase modulations the power spectrum of the scattered light exhibits narrowing of the central peak due to the modified decay rates. For strong phase modulations side lobes appear symmetrically around the central peak reflecting additional oscillation frequencies.Comment: 4 pages, 4 figure

Equatorial X-rays and their effect on the lower mesosphere

On the night of May 23/24, 1975, a sequence of rocket and balloon experiments was launched from Chilca Base, Peru (12.5 deg S, 76.8 deg W, magnetic dip = - 0.7 deg). Detailed analysis and comparisons of the data yielded the first direct measurement of lower mesospheric response to a galactic X-ray source. This result could only have been determined at the equator, where cosmic ray background effects are minimal. The objective of the experiments was to seek out the equatorial energetic electron belt, sporadically reported to contain fluxes near auroral levels, measure the bremsstrahlung radiation produced by this particle belt, and determine the influence of this radiation on the middle atmosphere. High altitude rocket payloads (Nike Tomahawk 18.170 and 18.171) were launched to probe the thermosphere during and following the anticipated downward drift period. Each carried an on-axis X-ray scintillation detector and Geiger Mueller energetic electron detectors. Magnetometers and lunar sensors were used to determine payload aspect

Measuring hydraulic fracture apertures: A comparison of methods

Hydraulic fracture apertures predominantly control fluid transport in fractured rock masses. Hence, the objective of the current study is to investigate and compare three different laboratory-scale methods to determine hydraulic apertures in fractured (Fontainebleau and Flechtinger) sandstone samples with negligible matrix permeability. Direct measurements were performed by using a flow-through apparatus and a transient-airflow permeameter. In addition, a microscope camera permitted measuring the mechanical fracture apertures from which the corresponding hydraulic apertures were indirectly derived by applying various empirical correlations. Single fractures in the sample cores were generated artificially either by axial splitting or by a saw cut resulting in hydraulic apertures that ranged between 8 and 66 µm. Hydraulic apertures, accurately determined by the flow-through apparatus, are used to compare results obtained by the other methods. The transient-airflow permeameter delivers accurate values, particularly when repeated measurements along the full fracture width are performed. In this case, the derived mean hydraulic fracture apertures are in excellent quantitative agreement. When hydraulic apertures are calculated indirectly from optically determined mechanical apertures using empirical equations, they show larger variations that are difficult to compare with the flow-through-derived results. Variations in hydraulic apertures as observed between methods are almost certainly related to differences in sampled fracture volume. Overall, using direct flow-through measurements as a reference, this study demonstrates the applicability of portable methods to determine hydraulic fracture apertures at both the laboratory and outcrop scales

A Variational Principle for Eigenvalue Problems of Hamiltonian Systems

We consider the bifurcation problem $u'' + \lambda u = N(u)$ with two point boundary conditions where $N(u)$ is a general nonlinear term which may also depend on the eigenvalue $\lambda$. We give a variational characterization of the bifurcating branch $\lambda$ as a function of the amplitude of the solution. As an application we show how it can be used to obtain simple approximate closed formulae for the period of large amplitude oscillations.Comment: 10 pages Revtex, 2 figures include

Varieties of Limited Access Orders: The nexus between politics and economics in hybrid regimes

This article advances our understanding of differences in hybrid stability by going beyond existing regime typologies that separate the study of political institutions from the study of economic institutions. It combines the work of Douglass North, John Wallis, and Barry Weingast (NWW) on varieties of social orders with the literature on political and economic regime typologies and dynamics to understand hybrid regimes as Limited Access Orders (LAOs) that differ in the way dominant elites limit access to political and economic resources. Based on a measurement of political and economic access applied to seven post‐Soviet states, the article identifies four types of LAOs. Challenging NWW's claim, it shows that hybrid regimes can combine different degrees of political and economic access to sustain stability. Our typology allows to form theoretical expectations about the kinds of political and/or economic changes that will move different types of LAOs toward more openness or closure

Advancing the time of ripeness of grapes by the application of methyl 2-(ureidooxy) propionate (a growth retardant)

Methyl 2-(ureidooxy) propionate (MUP), a plant growth retardant, hastened the ripening of grape berries of Vitis vinifera L. cultivars Mataro and Sultana by about 2 weeks and 1 week, respectively. The vines were sprayed with 0.1 % solution of MUP about halfway :through the first rapid growth phase of the fruit and again 2 weeks later. Terminal and lateral shoot growth was inhibited. Ripening of berries was advanced as measured by development of colour, and changes in titratable acid and reducing sugar content. The earlier ripening of the berries may have been due to hormonal changes but the advancement was much greater than that found previously with abscisic acid or ethylene applied during the slow growth stage of berry development.Die Beschleunigung des Reifezeitpunktes von Trauben durch die Anwendung vonMethyl-2-(ureidooxy)-Propionat, einen WachstumsdämpferMethyl-2-(ureidooxy)-Propionat (MUP), welches das Pflanzenwachstum verlangsamt, beschleunigte bei den Vitis-vinifera-Sorten Mataro und Sultana die Beerenreife um etwa 2 Wochen bzw. 1 Woche. Die Reben wurden etwa in der Mitte der ersten raschen Wachstumsphase der Beeren und ein weiteres Mal 2 Wochen später mit einer 0,1%igen MUP-Lösung besprüht. Das terminale und laterale Triebwachstum war gehemmt. Die Beerenreife war beschleunigt, wie die Entwicklung der Beerenfarbe und die Veränderungen im Gehalt an titrierbarer Säure und reduzierenden Zuckern zeigten. Die frühzeitigere Beerenreife könnte auf hormonale Veränderungen zurückgehen; allerdings war die Reife viel stärker beschleunigt als im Fall früherer Versuche, in denen während der langen Wachstumsphase der Beerenentwicklung Abscisinsäure oder Äthylen angewandt worden waren

The Effect of Diethylstilbestrol on the Digestibility of Dry Matter and Nitrogen and on Nitrogen Retention in Lambs

Although the usefulness of orally administered diethylstilbestrol (stilbestrol) in increasing weight gains and feed efficiency of fattening cattle has been established, little is known concerning the mechanism by which it exerts its beneficial effect. Two possible modes of action may exist. First, the stilbestrol may have some effect on the rumen microorganisms which might cause an increased digestion of feed in the rumen. Brooks et al. (1954) have shown that stilbestrol increased the digestibility of cellulose in the artificial rumen. They also obtained increased cellulose and protein digestion in sheep when stilbestrol was fed. However the levels fed the sheep were considerably above the mg. per lamb per day reported to be effective with lambs (Hale et al. 1955). Sykes et al. (1956) reported an increase in crude fiber digestibility and a decrease in protein digestibility with lactating cows when stilbestrol was fed. Digestibility of the dry matter of the ration tended to be improved but the differences were not statistically significant. Erwin et al. (1956) reported stilbestroI had no effect on digestibility of dry matter, crude fiber, crude protein or ether extract with steers. Secondly, the orally fed stilbestrol may exert some action on the metabolism of the animal\u27s tissue which is thought to occur when the stilbestrol is implanted (Clegg and Cole, 19 54). It has been shown that implanted stilbestrol increased nitrogen retention but had no effect on ration digestibility (Jordan 1953: Whitehair et al. 1953). Bell et al. (1955) found that orally fed stilbestrol increased nitrogen retention in lambs. Presumably this action is brought about by the absorbed stilbestrol acting similar to that on the implanted stilbestrol. The objectives of this report were to study the effects of different levels of stilbestrol upon the digestibility of dry matter and crude protein and on nitrogen retention with wether lambs