1,313 research outputs found

    A Comparative Study of the Regulatory Treatment of Enhanced Services in the United States and the European Community

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    The telecommunications industry and the data processing industry have become integral parts of the world economy. Furthermore, over the years, these services have come to complement each other. The result has been the development of services which are made up of both communications and data processing components. For the past twenty years, the FCC has struggled to develop rules that will allow common carriers in the United States to take advantage of their economies of scope while preventing or minimizing the pernicious effects of cross-subsidization and bottlenecks. As a result, complicated rules, and definitions attempting to draw a line between basic and enhanced services have evolved. In addition, the operators of bottleneck facilities have been prohibited from offering many enhanced services. More recently, the Commission of the European Economic Community ( EEC ) has published the Green Paper on Telecommunications, which proposes rules in this area, and attempts to integrate the EEC\u27s enhanced services and data processing markets across its Member States\u27 national boundaries. One of the effects of the Green Paper probably will be that the Member States will base their definitions of basic and enhanced services on characteristics of the markets for those services, such as the level of demand for the service and the availability of economies of scale and scope, rather than the FCC method of basing the definitions on characteristics of the services themselves, such as how much the services alter the form or content of the consumer\u27s information. The other effect of the Green Paper probably will be that the operators of bottleneck facilities will be allowed to offer most enhanced services

    Analytical description of spin-Rabi oscillation controlled electronic transitions rates between weakly coupled pairs of paramagnetic states with S=1/2

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    We report on an analytical description of spin-dependent electronic transition rates which are controlled by a radiation induced spin-Rabi oscillation of weakly spin-exchange and spin-dipolar coupled paramagnetic states (S=1/2). The oscillation components (the Fourier content) of the net transition rates within spin-pair ensembles are derived for randomly distributed spin resonances with account of a possible correlation between the two distributions that correspond to the two individual pair partners. The results presented here show that when electrically or optically detected Rabi spectroscopy is conducted under an increasing driving field B_ 1, the Rabi spectrum evolves from a single resonance peak at s=\Omega_R, where \Omega_R=\gamma B_1 is the Rabi frequency (\gamma is the gyromagnetic ratio), to three peaks at s= \Omega_R, s=2\Omega_R, and at low s<< \Omega_R. The crossover between the two regimes takes place when \Omega_R exceeds the expectation value \delta_0 of the difference of the Zeeman energies within the pairs, which corresponds to the broadening of the magnetic resonance lines in the presence of disorder caused by hyperfine field or distributions of Lande g-factors. We capture this crossover by analytically calculating the shapes of all three peaks at arbitrary relation between \Omega_R and \delta_0. When the peaks are well-developed their widths are \Delta s ~ \delta_0^2/\Omega_R.Comment: 10 page, 5 figure

    Consecutive bilateral decompression retinopathy after mitomycin C trabeculectomy: a case report

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    BACKGROUND: After a successful trabeculectomy, a sudden intraocular pressure decrease may alter the intracranial to intraocular pressure ratio and cause decompression retinopathy. Frequent Valsalva maneuvers may also play a role in its pathogenesis. This condition may manifest as multiple retinal hemorrhages, edema of the optic disc, macular edema, or a sudden decrease in visual acuity postoperatively. Outcomes for patients are usually good, with spontaneous resolution occurring within a matter of weeks. It has been rarely reported in the literature as a bilateral condition. CASE PRESENTATION: We present a case of consecutive bilateral decompression retinopathy in a 54-year-old severely obese Caucasian woman (body mass index 37 kg/m(2)) with open angle glaucoma and a poor history of medical therapeutic compliance, who chose surgical treatment based on her inability to consistently use ocular drops. Our patient underwent a trabeculectomy with mitomycin C in both eyes, with surgeries taking place 3 months apart. After the first surgery, 2 weeks postoperatively, she complained of decreased visual acuity. Examination of her right eye fundus revealed multiple retinal hemorrhages and disc edema. There was a similar pattern in her left eye, this time including maculopathy. Her visual acuity and fundoscopic changes resolved spontaneously over a period of a month in both cases. Currently, our patient has well-controlled bilateral intraocular pressure, ranging between 14 and 16 mmHg, without hypotensive medication. CONCLUSIONS: Decompression retinopathy is a potential complication after glaucoma surgery, but has rarely been described as a bilateral consecutive condition. A comprehensive approach could help to anticipate its occurrence and manage it.info:eu-repo/semantics/publishedVersio

    To Eat or Not to Eat Red Meat. A Closer Look at the Relationship Between Restrained Eating and Vegetarianism in College Females

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    Previous research has suggested that vegetarianism may serve as a mask for restrained eating. The purpose of this study was to compare the dietary habits and lifestyle behaviors of vegetarians (n = 55), pesco-vegetarians (n = 28), semi-vegetarians (n = 29), and flexitarians (n = 37), to omnivores (n = 91), who do not restrict animal products from their diets. A convenience sample of college-age females completed questionnaires about their eating habits, food choice motivations, and personality characteristics. Results indicated that while vegetarians and pesco-vegetarians were more open to new experiences and less food neophobic, they were not more restrained than omnivores. Rather semi-vegetarians; those who restricted only red meat from their diet, and flexitarians; those who occasionally eat red meat, were significantly more restrained than omnivores. Whereas food choices of semi-vegetarians and flexitarians were motivated by weight control, vegetarians and pesco-vegetarians’ food choices were motivated by ethical concerns. By focusing specifically on semi-vegetarian and flexitarian subgroups, more effective approaches can be developed to ensure that their concerns about weight loss do not lead to unhealthful or disordered eating patterns

    Electrical Detection and Magnetic-Field Control of Spin States in Phosphorus-Doped Silicon

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    Electron paramagnetic resonance of ensembles of phosphorus donors in silicon has been detected electrically with externally applied magnetic fields lower than 200 G. Because the spin Hamiltonian was dominated by the contact hyperfine term rather than by the Zeeman terms at such low magnetic fields, superposition states α∣↑↓>+β∣↓↑> \alpha{}| \uparrow \downarrow >+\beta{}| \downarrow \uparrow > and −β∣↑↓>+α∣↓↑>-\beta{}| \uparrow \downarrow > + \alpha{}| \downarrow \uparrow > were formed between phosphorus electron and nuclear spins, and electron paramagnetic resonance transitions between these superposition states and ∣↑↑>| \uparrow \uparrow > or ∣↓↓>| \downarrow \downarrow > states are observed clearly. A continuous change of α\alpha{} and β\beta{} with the magnetic field was observed with a behavior fully consistent with theory of phosphorus donors in silicon.Comment: 6 pages, 5 figure

    Validation of a clinical and genetic model for predicting severe COVID-19

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    Using nested case-control data from the Lifelines COVID-19 cohort, we undertook a validation study of a clinical and genetic model to predict the risk of severe COVID-19 in people with confirmed COVID-19 and in people with confirmed or self-reported COVID-19. The model performed well in terms of discrimination of cases and controls for all ages (area under the receiver operating characteristic curve (AUC) = 0.680 for confirmed COVID-19 and AUC = 0.689 for confirmed and self-reported COVID-19) and in the age group in which the model was developed (50 years and older; AUC = 0.658 for confirmed COVID-19 and AUC = 0.651 for confirmed and self-reported COVID-19). There was no evidence of over- or under-dispersion of risk scores but there was evidence of overall over-estimation of risk in all analyses (all P < 0.0001). In the light of large numbers of people worldwide remaining unvaccinated and continuing uncertainty regarding vaccine efficacy over time and against variants of concern, identification of people at high risk of severe COVID-19 may encourage the uptake of vaccinations (including boosters) and the use of non-pharmaceutical inventions
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