However, it is possible to acquire PET images using a conventional dual-head gamma camera fitted with a coincidence detector.

However, strong topographic contrast is produced by collecting back-scattered electrons from one side above the specimen using an asymmetrical, directional BSE detector ; the resulting contrast appears as illumination of the topography from that side.

However, on March 26, 1983, the first test, known as the Cabra event, was performed in an underground shaft and resulted in marginally positive readings that could be dismissed as being caused by a faulty detector.

However as he moved about the room trying to test it, the detector would mysteriously work, and then stop again.

However, since energy detection is inherently " square-law " detection, it intrinsically mixes any optical frequencies present on the detector.

However if the detector is shot noise dominated, the noise will be proportional to the square root of the power, thus for a broad boxcar spectrum ( continuous broadband source ), the noise is proportional to the square root of m, thus precisely offset the Fellgett's advantage.

However, far fewer CTs of this design have been produced, mainly due to the higher cost associated with building a much larger X-ray tube and detector array.

However, it was one Lieutenant Jozef Stanislaw Kosacki, a Polish officer attached to a unit stationed in St Andrews, Fife, Scotland, during the early years of World War II, who refined the design into a practical Polish mine detector.

However, when a superior told him that he would have to take a lie detector test to join, Hanssen changed his mind.

However, his work, and the patent, went somewhat unnoticed in the western scientific world, as on August 30, 1906, Greenleaf Whittier Pickard filed a patent for a silicon crystal detector, which was granted on November 20, 1906.

However, in optics one cannot measure the electric field directly as it oscillates much faster than any detector ’ s time resolution.

However, there can be differences between models of turbidimeters, depending upon the arrangement ( geometry ) of the source beam and the detector.

However, the dimensions of the Laue zones are proportional to the inverse square of the electron energy meaning that more information is recorded at the detector at higher incident electron energies.

However, the US embassy in Delhi issued a formal denial that Fernandes had been strip-searched, and said that, " Fernandes was not strip-searched but a security wand was waved over him when a key in his pocket set off the metal detector.

However, the velocities of the scattered neutrons can be determined afterwards by measuring the time of flight of the neutrons between the sample and neutron detector.

However, a change in frequency will occur as a result of the Doppler principle, when a person or object is moving towards or away from the detector.

However the 2001 Mori report suggests that radar detector users posed a 28 % less risk of accident.

However, the Geiger counter could not distinguish X-rays produced from specific elements and in 1950, Castaing added a quartz crystal between the sample and the detector to permit wavelength discrimination.

However, the instrumental response of the source, detector, and electronics can be measured, usually from scattered excitation light.

However, given the limits on input power ( damage threshold ) and detector noise ( integration time ), the signal from a single transition can be collected much faster in practical situation ( a factor of 10 < sup > 5 </ sup >) using CARS.

However, she has trouble getting a transmission through and ends up staying on air long enough for her radio location to be pinpointed by a German detector van.

However, posted limits are in place on many dangerous or congested stretches as well as where traffic noise or pollution poses a problem.

However, according to recent research, the original form was indeed Avalokitasvara with the ending a-svara (" sound, noise "), which means " sound perceiver ", literally " he who looks down upon sound " ( i. e., the cries of sentient beings who need his help ; a-svara can be glossed as ahr-svara, " sound of lamentation ").

However, 20th-century composer John Cage thought that any sound can be music, saying, for example, " There is no noise, only sound.

However, shot noise in the raw data is prominent in the reconstructed images and areas of high tracer uptake tend to form streaks across the image.

However, wear and decomposition of the wheel, as well as the direct mechanical coupling to a vibrating motor, introduced low-frequency noise (" rumble ") and speed variations (" wow and flutter ") into the sound.

However, transportation planners use noise mitigation strategies to minimize these effects.

However, the digital circuit will calculate more repeatably, because of its high noise immunity.

However, these cables had other impairments besides Gaussian noise, preventing such rates from becoming practical in the field.

However, in digital and radio frequency PCBs, the major reason for using large ground planes is to reduce electrical noise and interference being coupled from one part of the circuit to another through the ground ( ground loops ), and crosstalk between adjacent circuit traces.

However, in the case of satellite communications systems, where the antenna is pointed out into cold space, the antenna effective temperature is often colder than 290 K. In these cases a 2 dB improvement in receiver noise figure will result in more than a 2 dB improvement in the output signal to noise ratio.

However in many cases the input source's noise temperature is much higher, such as an antenna at lower frequencies where atmospheric noise dominates.

However one must check that the noise figure of the second stage is not so high ( or that the gain of the first stage is so low ) that there is SNR degradation due to the second stage anyway.

However when the other noise source is at a fixed level, such as thermal noise, increasing N ( the DC current or light level, etc.

However, shot noise is temperature and frequency independent, in contrast to Johnson – Nyquist noise, proportional to temperature, and flicker noise, with the spectral density decreasing with the frequency.

However this reduction in shot noise does not apply when the current results from random events at a potential barrier which all the electrons must overcome due to a random excitation, such as by thermal activation.

However both are instances of white noise and thus cannot be distinguished simply by observing them even though their origins are quite dissimilar.

However the same noise source is present with higher light intensities measured by any photodetector, and is directly measurable when it dominates the noise of the subsequent electronic amplifier.

However this amplifies noise ,< ref name =" Christy1998 "> increases inter-satellite calibration biases and enhances surface contamination.

However, humans still differentiate between white noise and pink noise with ease.

However, he wrongly posed the notion that the water was evaporating.

However, unlike Johnson, Hodge confined the term to exclude those like Asa Gray who combined Christian faith with support for Darwin's natural selection theory, before answering the question posed in the book's title by concluding: " It is Atheism.

However, those programs were neither egalitarian nor universal, excluding many minority groups and other people whom they felt posed a threat to the future health of the German people.

However, the submarine fleet was greatly expanded and posed a major threat to the British supply system.

However, the Cathars were the first mass heretical organization in the second millennium that posed a serious threat to the authority of the Church.

However, Muslim Arab invaders, who in 640 had conquered Egypt, posed a threat to the Christian Nubian kingdoms.

However, both versions of the amendment posed serious challenges in being ratified by three-fourths of the states.

However, Leopold also posed formidable problems as a candidate, for his succession would have reunited the elements of the powerful Spanish-Austrian Habsburg Empire of the sixteenth century.

However it was, by the end of the year Bertrada and Charlemagne had successfully encircled Carloman: Charlemagne had married Desiderata, the daughter of the Lombard king Desiderius, Carloman's immediate eastern neighbor, and the marriage created an alliance between Charlemagne and the Lombards ; Bertrada had also secured for Charlemagne the friendship of Tassilo, Duke of Bavaria, her husband's nephew ; she had even attempted to secure Papal support for the marriage by arranging for Desiderius to cede to Rome certain territories to which the Papacy laid claim, although Pope Stephen III remained in theory hostile to an alliance between his allies the Franks and his enemies the Lombards, and in reality deeply conflicted between the threat the Lombards posed to him and the chance to dispose of the anti-Lombard Christopher the Primicerius, the dominant figure at the Papal court.

However, the competitive marketplace has posed problems for some.

However, Raffles was able to charm the man and to reassure him that the Dutch posed no threat in the area.

However, In the early days of Third Reich, the Romanies posed a problem for Hitler ’ s racial ideologues: the Romani language is one of the Indo-Aryan languages, originating in northern India.

However, the allegorical meanings of the early and medieval church were of a different kind than those posed by Kant and the Enlightenment.

However, she and Crow both acknowledge the difficulties posed by their differences, such as Janey's preference for worms as pizza topping.

However, new zoning laws and planning difficulties posed by Glasgow City Council look set to push many of these long-established facilities out of the city in the near future.

However the NFL reinstated the Maroons the following year after fears that the team would join Red Grange's upstart American Football League, which posed a threat to the league.

As for the poor and plain folk, I shall treat them as brothers .” However, when Razin sailed by Tsartisyn, Unkovsky did not attack ( possibly either because Unkovsky felt that Razin posed a threat or the guards of Tsaritsyn sympathized with Razin ’ s Cossacks ).

However, Caligula was aware of the potential threat Macro posed and soon removed him from office.

However, Zhu Bajie's indulgence in women led him to the Gao Family Village, where he posed as a normal being and wedded a maiden.

However, in most common law jurisdictions, the right to remain silent allows any person questioned by police merely to refuse to answer questions posed by an investigator without giving any reason for doing so.

However, if such people had posed as third-party supporters in swing states, all they could do is trick John Kerry supporters in staunchly Republican states to vote for a third-party candidate — which wouldn't change the outcome of the election ( since George W. Bush would win those states anyway ).

However, Henry also saw the danger posed by the Duke of Guise, who was gaining more and more power.

However, this posed a new problem — how is it possible to have synthetic knowledge that is not based on empirical observation — that is, how are synthetic a priori truths possible?

However, his greatest ambition was for a pre-emptive war against Serbia in order to neutralize the threat that he believed they posed, and at the same time change the political balance within Austria-Hungary against the Magyars by incorporating more Slavs.