Innocence Lost: Simulation Scenarios: Prospects and Consequences

Those who believe suitably programmed computers could enjoy conscious experience of the sort we enjoy must accept the possibility that their own experience is being generated as part of a computerized simulation. It would be a mistake to dismiss this is just one more radical sceptical possibility: for as Bostrom has recently noted, if advances in computer technology were to continue at close to present rates, there would be a strong probability that we are each living in a computer simulation. The first part of this paper is devoted to broadening the scope of the argument: even if computers cannot sustain consciousness (as many dualists and materialists believe), there may still be a strong likelihood that we are living simulated lives. The implications of this result are the focus of the second part of the paper. The topics discussed include: the Doomsday argument, scepticism, the different modes of virtual life, transcendental idealism, the Problem of Evil, and simulation ethics

Role of Implantable Cardioverter Defibrillators in the Treatment of Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is an important cardiovascular disease with sudden cardiac death as the most devastating presentation. Implantable cardioverter defibrillators (ICD) are the optimal therapy for prevention of sudden death from ventricular tachycardia or fibrillation of any cause. While there is no controversy with implanting ICDs in patients who have already survived a cardiac arrest, identifying high-risk patients for primary prevention in this disease remains a challenge. Implanting ICDs in patients with HCM is an important clinical consideration since many individuals could achieve normal or near-normal lifespans with this protection

Expanding the range of chromatic dispersion monitoring with two-photon absorption in semiconductors

Chromatic dispersion monitoring based on two-photon absorption (TPA) in semiconductors is very attractive because it does not need any high speed electronic devices (Inui, 2002). However, at present the dispersion monitoring range is limited to half of the Talbot dispersion which is defined as DTalbot = T2c/lambda2 (Wielandy, 2004), T is the period of the signal pulse sequence. In this work we propose a scheme to expand this monitoring range

Technical service as a marketing tool for industrial goods

Thesis (M.B.A.)--Boston Universit

Active-Snubbing Or Passive-Snubbing for Fast Switches?

As power-switches improve, the primary function of switching-aid circuits changes from modifying the shape or rate-of-traverse of V-I loci within devicesafe-operating-areas (SOA's), to clamping transient current and voltage, at turn-on and turn-off, below peak current and voltage ratings. Also, as deviceruggedness and device parameters are improved, or made less variable between devices and with operating conditions, active-snubbing or active-clamping becomes feasible, whereby the magnitude of peak-current at turn-on and peak-voltage at turn-off are limited by gate or drive-circuit control, or inherently by the devices themselves. Examples have been reported, however, none of these adequately compares active and passive snubbing, or exposes salient disadvantages in active-snubbing. A more objective appraisal of active snubbingis attempted here, which uses as its basis for comparison; turn-on and turn-off commutation energy-loss, on-state energy-loss, overload capacity,and turn-on and turn-off delay. Irrespective of whether active or passive snubbers or clamps are used, switch turn-off voltage-waveforms are often characterised by fast voltage-overshoot above the dc-supply voltage, or above the threshold-level of voltage-clamps, when used. High-frequency ringinginevitably follows turn-off, or the beginning or end of voltage-clamping. The cause and solution are examined

Evaluating the reduction in snubbing with soft-recovery devices and the effect of resistor inductance

The effects of current-fall shapes on RC-snubber performance are examined to determine if smaller snubbers that remain tolerant to varying current-fall shapes and durations and give lower power-losses can be used. The effects of component imperfections on RC-snubber performance, the optimization of RC-snubbers with nonabrupt current-falls, the sensitivity of nonabrupt snubbers to current-fall variations, and the energy losses associated with nonabrupt snubbers are discussed. It is shown that finely tuning RC-snubber components to take into account nonabrupt current fall, allows reduced snubber capacitance to be used under certain operating conditions. However, voltage-responses become more sensitive to current-fall shape, diode switching-loss is increased by several orders of magnitude, and there appears to be no significant energy-loss advantage with sinusoidally modulated current

Optimising snubbers for high-current emitter-switched transistors

The authors analyse a soft voltage-clamp to find a simple design procedure for optimising series-snubber and clamp reset-time circuits for a given voltage rise above the supply-rail. This analysis is applicable to other switches requiring voltage clamping rather than load-line tailoring, including MOSFETs. Their advantages of: reduced power dissipation over shunt-snubbers; current-dependent power dissipation, independent of supply-voltage; and absence of cross-current peaks in phase-legs are likely to promote continued usag

Purification and characterisation of putative protein allergens from the seeds of the castor oil plant, "Ricinus communis"

The identification, purification and characterisation of putative castor bean allergens has been achieved together with some studies on the synthesis of castor bean cDNA undertaken as a prerequisite to the isolation of allergen cDNA clones. At least four proteins have been identified which bind immunoglobulin E from the pooled sera of ten patients allergic to castor beans (CB pool). The apparent molecular weights of these proteins are 10,000, 34,000, 48,000 and 50.000. On the basis of their ability to elicit an IgE response these proteins are considered to be putative castor bean allergens. The 10 kDa putative allergen has been identified as the large subunit of a heterodimeric 2S storage albumin purified in the course of this study. The putative 2S allergen has been shown to be identical to a castor bean 2S albumin previously purified and sequenced by Li and coworkers (Li et al.. 1977; Sharief and Li, 1982). In consequence, the putative 2S allergen has been called Li's protein. Li's protein has been shown to be a trypsin inhibitor. Li's protein may be encoded by a multigene family and is initially translated as a 32.5 kDa precursor, almost three times the mass of the mature protein (11 kDa) as determined by amino acid sequencing. IgE from the CB pool specifically binds to two components of the complex crystalloid group of storage proteins. The 34 kDa subunits of these crystalloid proteins may be the putative 34 kDa allergen. The binding of IgE from the CB pool by components of the crystalloid complex may be the result of a cross-reaction with IgE raised against the 2S allergen. The putative crystalloid allergens have been substantially purified by ion-exchange chromatography. The feasibility of using chromatofocusing to rigorously purify the putative crystalloid allergens and to separate the individual polypeptides has been investigated. The SI nuclease method was found to be preferable to the RNAse H method for the synthesis of castor bean cDNA. The 48 kDa and 50 kDa putative castor bean allergens have not been identified