14,182 research outputs found

    Contraception and the Contralife Will

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    Father Connor received his Ph.D. in philosophy from the Lateran University in Rome. He points out that “Intending the good is a subjective operation deriving from an intellectual objective perception of being. The being that I perceive is the esse of my personal self which is thrusting to fulfillment through acts. The person and his/her acts are the grounding of what I mean by “good” or “bad”. The evil of contraception, then is not an intention against the life of a future child, but the nonconformity of the will with the double structure (love-making/life giving) of the coital act which is a manifestation of the intercoursing process. “The evident weakness of the contralife will shows in the inability to apply it uniformly throughout sexual morality. For example, in in vitro fertilization, the will is pro-life, yet the “manufacturing” of the child is evil. They then have recourse to other principles ad hoc.” </jats:p

    Internet authentication based on personal history - a feasibility test

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    On the Internet, there is an uneasy tension between the security and usability of authentication mechanisms. An easy three-part classification is: 'something you know' (e.g. password); 'something you hold' (e.g. device holding digital certificate), and 'who you are' (e.g. biometric assessment) [9]. Each of these has well-known problems; passwords are written down, guessable, or forgotten; devices are lost or stolen, and biometric assays alienate users. We have investigated a novel strategy of querying the user based on their personal history (a 'Rip van Winkle' approach.) The sum of this information is large and well-known only to the individual. The volume is too large for impostors to learn; our observation is that, in the emerging environment, it is possible to collate and automatically query such information as an authentication test. We report a proof of concept study based on the automatic generation of questions from electronic 'calendar' information. While users were, surprisingly, unable to answer randomly generated questions any better than impostors, if questions are categorized according to appropriate psychological parameters then significant results can be obtained. We thus demonstrate the potential viability of this concept

    Wind-tunnel acoustic results of two rotor models with several tip designs

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    A three-phase research program has been undertaken to study the acoustic signals due to the aerodynamic interaction of rotorcraft main rotors and tail rotors. During the first phase, two different rotor models with several interchangeable tips were tested in the Langley 4- by 7-Meter Tunnel on the U.S. Army rotor model system. An extensive acoustic data base was acquired, with special emphasis on blade-vortex interaction (BVI) noise. The details of the experimental procedure, acoustic data acquisition, and reduction are documented. The overall sound pressure level (OASPL) of the high-twist rotor systems is relatively insensitive to flight speed but generally increases with rotor tip-path-plane angle. The OASPL of the high-twist rotors is dominated by acoustic energy in the low-frequency harmonics. The OASPL of the low-twist rotor systems shows more dependence on flight speed than the high-twist rotors, in addition to being quite sensitive to tip-path-plane angle. An integrated band-limited sound pressure level, limited by 500 to 3000 Hz, is a useful metric to quantify the occurrence of BVI noise. The OASPL of the low-twist rotors is strongly influenced by the band-limited sound levels, indicating that the blade-vortex impulsive noise is a dominant noise source for this rotor design. The midfrequency acoustic levels for both rotors show a very strong dependence on rotor tip-path-plane angle. The tip-path-plane angle at which the maximum midfrequency sound level occurs consistently decreases with increasing flight speed. The maximum midfrequency sound level measured at a given location is constant regardless of the flight speed

    Noise reduction studies for the Cessna model 337 (0-2) airplane

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    A study was undertaken to determine the noise reduction potential of the 0-2 airplane in order to reduce its aural detection distance. Static and flyover noise measurements were made to document the noise signature of the unmodified airplane. The results show that significant reductions in aural detection distance can be achieved by the combination of propeller geometry changes and the addition of engine exhaust mufflers. The best results were estimated for the aircraft equipped with a six-blade propeller operating at 3/4 engine speed in combination with a 3.49 cubic foot exhaust muffler installed on each engine. Detection distance for the modified aircraft is estimated to be reduced from about 4-1/4 miles to about 1-1/2 miles when the aircraft is operating at an altitude of 1,000 ft over grassy terrain. Reducing the altitude to 300 ft over a leafy jungle ground cover should reduce the aural detection distance to 0.9 miles. Reduced aural detection distances were also indicated for a modification utilizing a direct-drive six-blade propeller of reduced radius along with smaller exhaust mufflers

    Entanglement consumption of instantaneous nonlocal quantum measurements

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    Relativistic causality has dramatic consequences on the measurability of nonlocal variables and poses the fundamental question of whether it is physically meaningful to speak about the value of nonlocal variables at a particular time. Recent work has shown that by weakening the role of the measurement in preparing eigenstates of the variable it is in fact possible to measure all nonlocal observables instantaneously by exploiting entanglement. However, for these measurement schemes to succeed with certainty an infinite amount of entanglement must be distributed initially and all this entanglement is necessarily consumed. In this work we sharpen the characterisation of instantaneous nonlocal measurements by explicitly devising schemes in which only a finite amount of the initially distributed entanglement is ever utilised. This enables us to determine an upper bound to the average consumption for the most general cases of nonlocal measurements. This includes the tasks of state verification, where the measurement verifies if the system is in a given state, and verification measurements of a general set of eigenstates of an observable. Despite its finiteness the growth of entanglement consumption is found to display an extremely unfavourable exponential of an exponential scaling with either the number of qubits needed to contain the Schmidt rank of the target state or total number of qubits in the system for an operator measurement. This scaling is seen to be a consequence of the combination of the generic exponential scaling of unitary decompositions combined with the highly recursive structure of our scheme required to overcome the no-signalling constraint of relativistic causality.Comment: 32 pages and 14 figures. Updated to published versio

    Noise reduction studies for the U-10 airplane

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    A study was undertaken by the NASA Langley Research Center to determine the noise reduction potential of the U-10 airplane in order to reduce its aural detection distance. Static and flyover noise measurements were made to document the basic airplane noise signature. Two modifications to the airplane configuration are suggested as having the best potential for substantially reducing aural detection distance with small penalty to airplane performance or stability and control. These modifications include changing the present 3-blade propeller to a 5-blade propeller, changing the propeller diameter, and changing the propeller gear ratio, along with the use of an engine exhaust muffler. The aural detection distance corresponding to normal cruising flight at an altitude of 1,000 ft over grassy terrain is reduced from 28,000 ft (5.3 miles) to about 50 percent of that value for modification 1, and to about 25 percent for modification 2. For the aircraft operating at an altitude of 300 ft, the analysis indicates that relatively straightforward modifications could reduce the aural detection distance to approximately 0.9 mile. Operation of the aircraft at greatly reduced engine speed (1650 rpm) with a 1.3-cu-ft muffler provides aural detection distances slightly lower than modification 1

    Noise characteristics of the O-1 airplane and some approaches to noise reduction

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    A brief study of the O-1A airplane to determine possible means for reducing the aircraft aural detection distance was conducted. This effort involved measuring the noise signature of the basic airplane, devising methods to attenuate the noise, and then estimating the effect of several selected modifications on the aural detection distance of the aircraft. A relatively simple modification utilizing a 6.5 ft diameter, six-blade propeller and including a muffler having a volume of 0.725 cu ft is indicated to reduce the aural detection distance of the O-1 aircraft from about 6 miles at an altitude of 1,000 ft and 2 to 3 miles at an altitude of 300 ft to approximately half these values. The flyover noise data suggest that routing the exhaust stacks up and over the wing would provide immediate noise reduction of about 5 dB with an attendant reduction in detection distance. Furthermore, all these studies confirm the work of other investigators that the 1/3 octave band (center frequency=125 cps) is the most critical in reducing aural detection distance
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