Physiological responses of women to simulated weightlessness: A review of the first female bed-rest study

Subjects were exposed to centrifugation, to lower body negative pressure (LBNP), and to exericse stress both before and after bed rest. Areas studied were centrifugation tolerance, fluid electrolyte changes and hematology, tolerance to LBNP, physical working capacity, biochemistries, blood fibrinolytic activity, female metabolic and hormonal responses, circadian alterations, and gynecology. Results were compared with the responses observed in similarly bed-rested male subjects. The bed-rested females showed deconditioning responses similar to those of the males, although with some differences. Results indicate that women are capable of coping with exposure to weightlessness and, moreover, that they may be more sensitive subjects for evaluating countermeasures to weightlessness and developing criteria for assessing applicants for shuttle voyages

High-pt Particle Production at PHENIX

It has been established that "hard probes", observables involving high-momentum transfer, provide useful tools for studying the hot, dense medium created in nucleus-nucleus collisions at RHIC. The nuclear modification factor, azimuthal correlations, direct photon production, as well as the dependence of the nuclear modificaton factor on centrality and angle with respect to the reaction plane are critical for understanding the early dynamics of such heavy-ion collisions. We will review recent results from PHENIX for particle production at high-pT and discuss their implications.Comment: Proceedings from the Conference on the Intersections of Particle and Nuclear Physics, 30 May - 3 June 200

XMM Follow-Up Observations of Three Swift BAT-Selected Active Galactic Nuclei

We present XMM-Newton observations of three AGN taken as part of a hunt to find very heavily obscured Compton-thick AGN. For obscuring columns greater than 10^25 cm^-2, AGN are only visible at energies below 10 keV via reflected/scattered radiation, characterized by a flat power-law. We therefore selected three objects (ESO 417-G006, IRAS 05218-1212, and MCG -01-05-047) from the Swift BAT hard X-ray survey catalog with Swift X-ray Telescope XRT 0.5-10 keV spectra with flat power-law indices as candidate Compton-thick sources for follow-up observations with the more sensitive instruments on XMM-Newton. The XMM spectra, however, rule out reflection-dominated models based on the weakness of the observed Fe K-alpha lines. Instead, the spectra are well-fit by a model of a power-law continuum obscured by a Compton-thin absorber, plus a soft excess. This result is consistent with previous follow-up observations of two other flat-spectrum BAT-detected AGN. Thus, out of the six AGN in the 22-month BAT catalog with apparently flat Swift XRT spectra, all five that have had follow-up observations are not likely Compton-thick. We also present new optical spectra of two of these objects, IRAS 05218-1212 and MCG -01-05-047. Interestingly, though both these AGN have similar X-ray spectra, their optical spectra are completely different, adding evidence against the simplest form of the geometric unified model of AGN. IRAS 05218-1212 appears in the optical as a Seyfert 1, despite the ~8.5x10^22 cm^-2 line-of-sight absorbing column indicated by its X-ray spectrum. MCG -01-05-047's optical spectrum shows no sign of AGN activity; it appears as a normal galaxy.Comment: 18 pages including 4 figures, accepted by Ap

Firm Capabilities, Competition and Industrial Policies in a History-Friendly Model of the Computer Industry

In this paper, we explore some problems that industrial policy faces in industries characterized by dynamic increasing returns on the basis of a 'history friendly model' of the evolution of the computer industry. How does policy affect industry structure over the course of industry evolution? Is the timing of the intervention important? Do policy interventions have indirect and perhaps unintended consequences on different markets at different times? We focus on two sets of policies: antitrust and interventions aiming at supporting the entry of new forms in the industry. The results of our simulations show that, if strong dynamic increasing returns are operative, both through technological capabilities and through customer tendency to stick with a brand, there is little that antitrust and entry policy could have done to avert the rise of a dominant firm in mainframes. On the other hand, if the customer lock in effect had been smaller, either by chance or through policies that discouraged efforts of firms to lock in their customers, the situation might have been somewhat different. In the first place, even in the absence of antitrust or entry encouraging policies, market concentration would have been lower, albeit a dominant firm would emerge anyhow. Second, antitrust and entry encouraging policies would have been more effective in assuring that concentration would decrease. The leading firm would continue to dominate the market, but its relative power would be reduced. © Elsevier Science B.V

Pointwise tube formulas for fractal sprays and self-similar tilings with arbitrary generators

In a previous paper by the first two authors, a tube formula for fractal sprays was obtained which also applies to a certain class of self-similar fractals. The proof of this formula uses distributional techniques and requires fairly strong conditions on the geometry of the tiling (specifically, the inner tube formula for each generator of the fractal spray is required to be polynomial). Now we extend and strengthen the tube formula by removing the conditions on the geometry of the generators, and also by giving a proof which holds pointwise, rather than distributionally. Hence, our results for fractal sprays extend to higher dimensions the pointwise tube formula for (1-dimensional) fractal strings obtained earlier by Lapidus and van Frankenhuijsen. Our pointwise tube formulas are expressed as a sum of the residues of the "tubular zeta function" of the fractal spray in $\mathbb{R}^d$. This sum ranges over the complex dimensions of the spray, that is, over the poles of the geometric zeta function of the underlying fractal string and the integers $0,1,...,d$. The resulting "fractal tube formulas" are applied to the important special case of self-similar tilings, but are also illustrated in other geometrically natural situations. Our tube formulas may also be seen as fractal analogues of the classical Steiner formula.Comment: 43 pages, 13 figures. To appear: Advances in Mathematic