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1.
The United Parcel Service (UPS)–Motorola case study revolves around two major areas of information technology (IT) management: IT as a competitive tool and global outsourcing of IT projects. It provides an opportunity to become familiar with the decisions and actions taken by UPS to assure their competitive advantage in the turbulent courier services industry. In the IT outsourcing area, the case addresses managerial and technical issues associated with outsourcing IT projects across the global community. The case presents the specific factors that made this outsourcing project successful and discusses the development of the outsourcing relationships between UPS and Motorola (Israel), from initial negotiations to the creation of a strategic alliance between the two companies. A major point in this case is the gradual development of trust between the two sides, trust that led the two firms from being committed to a contract to becoming strategic partners.  相似文献   
2.
Angiotensin II (A II) and analogues were tested for their ability to restore electrical and mechanical activity to cardiac muscle preparations in which the fast Na+ channels had been inactivated by partial depolarization (22-27 mM K+) or by tetrodotoxin (TTX). The partially depolarized or TTX-blocked preparations were chosen because under these conditions electrical and mechanical responses are primarily Ca2+ -dependent. In depolarized rabbit right atria, A II restored spontaneous mechanical and electrical activity (measured by both intracellular and extracellular recording techniques). The frequency of action potential discharge was concentration-dependent; the threshold concentration of A II was 10(-10) M, the ED50 was 8 X 10(-9) M, and the maximum effect was observed at 5 X 10(-8) M. In contrast, depolarized guinea pig atria were insensitive to A II, Sar1-angiotensin II, and des-Asp1-angiotensin II, even at concentrations as high as 10(-5) M. Rabbit papillary muscle (TTX-blocked), embryonic (18-day) chick heart (partially depolarized) and chick heart reaggregates (TTX-blocked) responded similarly to rabbit atria in that A II (9.6 X 10(-7) M) restored both electrical and mechanical activity. We found that in these preparations the action of A II was unaffected by propranolol (5.0 X 10(-6) M to 5.0 X 10(-5) M) but was blocked by Mn2+ (10(-3) M), D-600 (1 X 10(-7) g/ml) and the specific A II antagonists Sar1-Ala8-angiotensin II (P-113) (5.0 X 10(-5) M) and Sar1-Ile8-angiotensin II (5.28 X 10(-5) M). We conclude that the positive inotropic effect of A II on the myocardium is due to its ability to increase transmembrane ion movements in or through the cell membrane. The ability of Mn2+ and D-600 to block this effect suggests that this ion movement is via the so-called "slow channels."  相似文献   
3.
The two-campus transport problem (TCTP) is a dial-a-ride problem with only two destinations. The problem is motivated by a transport problem between two campuses of an academic college. The two campuses are located in two different cities. Lecturers living in one city are sometimes asked to teach at the other city’s campus. The problem is that of transporting the lecturers from one campus to the other, using a known set of vehicles, so as to minimize the time the lecturers wait for their transport. We mathematically model the general TCTP, and provide an algorithm that solves it, which is polynomial in the number of lecturers. The algorithm is based on a reduction to a shortest path problem.  相似文献   
4.
Line narrowing has been traditionally achieved in solid-state 1H NMR spectroscopy by applying pulse sequences that combine multiple-pulse operations with magic-angle spinning (MAS), to effectively average out the dipole dipole homonuclear Hamiltonian. The present study explores a new alternative that departs from the usual concept of directly acting on the strongly coupled spins with radiofrequency pulses; instead, we seek to achieve a net homonuclear dipolar decoupling in solids by exploring the reintroduction of MAS-averaged heteronuclear dipolar couplings between the 1H nuclei and directly bonded 13C or 15N nuclei. This recoupling anti-recoupling (RaR) scheme thus relies on the recoupling of the dipolar interaction with heteronuclear spins, which, under fast MAS, will exceed the strength and will not commute with the homonuclear 1H 1H coupling one is intending to average out. Subsequent removal (“antiRecoupling”) of these heteronuclear interactions can lead to narrowed 1H resonances, without ever pulsing on the aforementioned channel. The line-narrowing properties of RaR are illustrated with numerical simulations and with experiments on model organic solids.  相似文献   
5.
Physiopathology of premature progesterone elevation   总被引:1,自引:0,他引:1  
OBJECTIVE: To determine the effects of the last hMG administration on plasma P and androgen profiles during controlled ovarian hyperstimulation (COH) for IVF-ET. DESIGN: Controlled clinical study. SETTING: The IVF-ET program of a tertiary outpatient care center, H?pital A. Béclère, Clamart, France. PATIENTS: Nine IVF-ET candidates aged 25 to 36 years having presented normal responses to COH in previous IVF-ET cycles. INTERVENTIONS: Controlled ovarian hyperstimulation was induced for IVF-ET using hMG after endogenous gonadotropins were suppressed with a time-release GnRH agonist. Just before the last hMG administration (225 IU), the participants were hospitalized for 24 hours for serial blood sampling. These occurred before (baseline) and after hMG administration, every 30 minutes for 1 hour, hourly for 4 hours, and every 3 hours for the remaining part of a 24-hour post-hMG observation period. MAIN OUTCOME MEASURE: Measurement of P, T, androstenedione (A), E2, FSH, and LH. RESULTS: Plasma P and androgens (T and A) increased significantly, reaching peak values 12 to 15 hours after hMG administration and decreased progressively thereafter, to reach values not significantly different from baseline 24 hours after hMG administration. Plasma E2 levels increased progressively and steadily during the 24-hour observation period. Plasma FSH levels remained constant after hMG administration while LH stayed undetectable. CONCLUSION: In COH cycles induced for IVF-ET, the hormonal profile after the last hMG injection suggests that hMG triggers an increase in plasma P and androgens that culminates 12 to 15 hours after hMG administration. This elevation in plasma P and androgens observed after hMG administration is likely to reflect a direct action of the LH and/or FSH components of hMG on granulosa cells. In some women these hormonal consequences of hMG treatment may impair endometrial receptivity in IVF-ET cycles.  相似文献   
6.
Cranes have come to symbolize building construction itself. They perform indispensable services in moving materials and components vertically and horizontally. Used since antiquity, their history is interrelated with the development of new power sources that replaced man and mule, first steam and later internal combustion, diesel, and electric engines. Mobile cranes can be rapidly deployed to lift heavy loads. New models with telescoping booms and all-terrain travel capability, compact urban machines, and even hybrids with tower cranes are beginning to replace the familiar lattice boom truck cranes. Mobile cranes have dominated the North American market, but a cultural change appears to be taking place toward tower cranes for building projects. Tower cranes, common in Europe for decades, are globally gaining in popularity with surging real estate developments. Ideal for dense urban environments and coming with a small footprint, they are available in a growing diversity of sizes and configurations. Sophisticated electronic controls and operator assistance devices are enhancing their safe and productive operation. While cranes occupy a central role on midrise and high-rise building projects, they operate in conjunction with other types of supporting equipment that are an essential part of the overall equipment array on today’s industrialized construction sites.  相似文献   
7.
8.
High shoring towers, the common shoring solution for high clearance construction, cause the entire formwork system to account for a remarkably high percentage of the cost of the constructed concrete element. However, data on work inputs in assembly and disassembly of high towers are scarce, and the reason lies in the difficulty in conducting the numerous work studies that would be needed to cover the wide variety of tower types offered by the market and the extensive range of heights to which towers are erected. A model is presented, based on a limited number of work studies, for the prediction of work inputs in the assembly and disassembly of shoring towers of two configurations, rising to heights of up to 30 m. Results of actual measured work input data for three tower models representing three tower types widely used on construction sites are presented. An insight is provided into the anatomy of tower erection, which should make possible use of the proposed methodology for the development of similar models for additional tower types.  相似文献   
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10.
Sigma receptors are found in motor and limbic areas in the brains of humans, non-human primates, and rodents. The most extensive pharmacological studies of ligand binding to sigma receptors have utilized brain tissue from guinea pigs, where two subtypes of sigma receptor, designated sigma1 and sigma2, have been identified. Few functional roles for sigma receptors have been described. Their location in guinea pig striatum, a terminal field of dopaminergic projections arising from the substantia nigra, suggested that this tissue would be a logical choice in which to examine physiological properties of sigma receptor activation. We found that sigma1 receptor agonists inhibited N-methyl-D-aspartate-stimulated [3H]dopamine release from guinea pig striatal slices in a concentration-dependent manner. The inhibition by sigma1 receptor agonists was reversed by a selective sigma1 receptor antagonist, as well as by a non-subtype-selective sigma receptor antagonist. The ability of agonists working through sigma1 receptors, but not through sigma2 receptors, to inhibit the stimulated release of catecholamines appears to be a unique characteristic of guinea pig striatum. We have previously reported that in rat striatum and hippocampus, as well as in guinea pig nucleus accumbens, prefrontal cortex, and hippocampus, activation of either sigma receptor subtype inhibits such release. Stimulated release of [3H]dopamine from guinea pig striatum was also inhibited by the phencyclidine receptor agonist dizocilpine, but this inhibition was not reversed by the sigma receptor antagonists. Therefore, the inhibition produced by sigma receptor agonists was not mediated via the phencyclidine binding site within the N-methyl-D-aspartate-operated cation channel. Our findings support the hypothesis that sigma receptor activation provides a mechanism of modulating dopamine release from striatum, and that striatal tissue from guinea pigs appears to be an appropriate model for characterizing sigma1 receptor-mediated effects.  相似文献   
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