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The purpose of the present paper is to give a comprehensive state of the art review of all electro-optical systems used to date for direct viewing of X-ray topographic images. Consideration is given to both direct conversion X-ray sensitive vidicon systems and to indirect conversion systems which use fluorescent screens to convert the X-ray image into a visible one. Included in this review is a discussion of the relative advantages and disadvantages of the various electro-optical systems, including cost, versatility, portability, simplicity of operation, sensitivity, and resolution capability.
In order to develop an optimum system for flash x-ray diffraction, consideration must be given to both optimum x-ray generation and optimum x-ray detection in the correct wavelength regime suitable for diffraction. Historically, most workers have concentrated their efforts in either the generation area or detection area, but not both. As early as 1942, experimental recording of Laue diffraction patterns was reported using a pulsed x-ray generator and exposure times of milliseconds. Recently, successful x-ray diffraction experiments have been reported with exposure times less than 100 nanoseconds.
The purpose of the present paper is to trace the development of generation and detection systems for flash x-ray diffraction and to summarize the present state-of-the-art for such systems. A comparative evaluation is presented for flash x-ray diffraction systems using generators which rely on increased electron beam current and those which rely on higher potential difference. Comparison is also made between detection systems incorporating film recording, scintillators fiber-optically coupled to photomultiplier tubes, and image-intensifier systems both lens and fiber-optically coupled to fluorescent screens.
A detailed description of the most rapid flash x-ray diffraction system developed to date is given. This system uses a Field Emission Fexitron single channel 300 kilovolt pulsed x-ray generator incorporating an x-ray tube with a beryllium output window. A fluorescent screen converts the x-ray diffraction image into a visible one and this visible image is focused on the first stage photocathode of an image intensifier tube either by direct fiber-optic coupling or by using a coupling lens. The image intensifier tube used is a cascaded three-stage electrostatic focus type with fiber-optic input and output faceplates and inter-stage couplers. Using this system Laue transmission diffraction patterns of single crystals and powder patterns of polycrystalline aggregates have been obtained with exposure times of 30 nanoseconds.
Considerable work has been undertaken in order to gain an understanding of the mechanisms responsible for the generation of recrystallization textures developed upon annealing of cold-worked metals. Most direct measurements have consisted of measuring the increase in average diameter of the largest grain growing into a polycrystalline aggregate. Experimental measurements of individual boundaries migrating into deformed single crystals, though of a more fundamental nature, have been made by far fewer investigators. This is probably due to the increased experimental difficulties associated with careful control of such experiments. Most previous investigators have made grain boundary migration measurements by the heat-cool-etch method, despite the fact that it has several marked disadvantages. Other investigators have constructed an X-ray goniometer furnace and used it to measure grain boundary migration rates while the test specimen was maintained at temperature. Since there have been no published reports of the use of such a system in the past thirteen years, it must be concluded that the technique was unsuccessful in general.
The system described in the present work is relatively simple in design and extremely simple to use. Not only does it permit absolute measurement of grain boundary position at temperature but it also permits boundary migration measurements to be made of extremely fast moving boundaries. The basic components of the system are as follows. A continuous spectrum X-ray beam is converted by a slit collimating system into a beam which is incident along the entire length of the test specimen. This beam is interrupted by a wire grid just prior to impingement on the test specimen. The test specimen is supported vertically in a furnace maintained at the temperature required for grain boundary migration. The various diffracted X-ray beams pass out of the furnace through a highly reflecting insulating baffle made from very thin aluminum foil and impinge on a fluorescent screen. This screen converts the X-ray image into a visible one which is amplified and recorded using the electro-optical system.
Synchrotron white beam transmission topography of GaAs as previously reported by the authors relied on scanning specimen and film synchronously through the incident x-ray beam to record transmission topographic images en film. Sometimes the total dose required for reasonable contrast on film carried with it enough thermal deposition to cause elastic warping of the wafer. To escape these problems, a real time system was assembled. This system included an image intensifier, a solid state camera, a computer board to frame-grab and digitize images, and appropriate image processing software. With this system, a three inch specimen was scanned from edge to edge in one minute. At this scan rate, the incident x-ray beam had to be significantly attenuated to avoid saturating the intensifier output.
Various electro-optical systems have been reported which permit intensification of X-ray diffraction patterns and thus a decrease in exposure time for recording and display of the X-ray images. Prior to 1966, all such electro-optical systems incorporated a large format X-ray image intensifier of the same type as conventionally used for medical and industrial fluoroscopy. In the past four years, a number of different systems have been reported which are superior to those developed prior to 1966. These systems may be grouped into two main categories, the large format variety for Laue diffraction applications, and the small format variety for topographic applications.
The purpose of the present paper is to describe the particular characteristics of both the large format and small format systems and to discuss the advantages and disadvantages associated with each type. Based on actual performance characteristics it will be shown that:
1.A multiple stage image intensifier system coupled to an external fluorescent screen is the most sensitive and only truly instantaneous system; it can be used with very weak X-ray intensities, the resolution is currently limited by the external fluorescent screen to 42μ the system is extremely versatile in that it can be used both for large format recording of Laue patterns as well as for small format recording of X-ray topographe; the system has a very long lifetime since nothing is altered by X-radiation.
2.An X-ray sensitive vidicon is the least sensitive; it must be used with extremely high intensity X-rays or long exposure times; the resolution is the highest at approximately 15μ and is limited by either bandwidth of the television system, the thickness of the X-ray sensitive target or the size of the electron beam at the target; due to the small size of the X-ray sensitive target the system can only be used for small format recording of X-ray topographs; the lifetime of the system is short since X-radiation causes degradation of the target.
To integrate electronic clinical decision support tools into clinical practice and to evaluate the impact on indwelling urinary catheter (IUC) use and catheter-associated urinary tract infections (CAUTIs).
Design, Setting, and Participants
This 4-phase observational study included all inpatients at a multicampus, academic medical center between 2011 and 2015.
Phase 1 comprised best practices training and standardization of electronic documentation. Phase 2 comprised real-time electronic tracking of IUC duration. In phase 3, a triggered alert reminded clinicians of IUC duration. In phase 4, a new IUC order (1) introduced automated order expiration and (2) required consideration of alternatives and selection of an appropriate indication.
Overall, 2,121 CAUTIs, 179,070 new catheters, 643,055 catheter days, and 2,186 reinsertions occurred in 3·85 million hospitalized patient days during the study period. The CAUTI rate per 10,000 patient days decreased incrementally in each phase from 9·06 in phase 1 to 1·65 in phase 4 (relative risk [RR], 0·182; 95% confidence interval [CI], 0·153–0·216; P<·001). New catheters per 1,000 patient days declined from 53·4 in phase 1 to 39·5 in phase 4 (RR, 0·740; 95% CI, 0·730; P<·001), and catheter days per 1,000 patient days decreased from 194·5 in phase 1 to 140·7 in phase 4 (RR, 0·723; 95% CI, 0·719–0·728; P<·001). The reinsertion rate declined from 3·66% in phase 1 to 3·25% in phase 4 (RR, 0·894; 95% CI, 0·834–0·959; P=·0017).
The phased introduction of decision support tools was associated with progressive declines in new catheters, total catheter days, and CAUTIs. Clinical decision support tools offer a viable and scalable intervention to target hospital-wide IUC use and hold promise for other quality improvement initiatives.
Six radio telescopes were operated as the first southern hemisphere VLBI array in April and May 1982. Observations were made at 2.3 and 8.4 Ghz. This array produced VLBI images of 28 southern hemisphere radio sources, high accuracy VLBI geodesy between southern hemisphere sites, and subarcsecond radio astrometry of celestial sources south of declination −45 degrees. This paper discusses only the astrophysical aspects of the experiment.
The impact of healthcare system integration on infection prevention programs is unknown. Using catheter-associated urinary tract infection (CAUTI) prevention as an example, we hypothesize that US Department of Veterans Affairs (VA) nursing homes have a more robust infection prevention infrastructure due to integration and centralization compared with non–VA nursing homes.
VA and non-VA nursing homes participating in the AHRQ Safety Program for Long-Term Care collaborative.
Nursing homes provided baseline information about their infection prevention programs to assess strengths and gaps related to CAUTI prevention via a needs assessment questionnaire.
A total of 353 of 494 nursing homes from 41 states (71%; 47 VA and 306 non-VA facilities) responded. VA nursing homes reported more hours per week devoted to infection prevention-related activities (31 vs 12 hours; P<.001) and were more likely to have committees that reviewed healthcare-associated infections. Compared with non-VA facilities, a higher percentage of VA nursing homes reported tracking CAUTI rates (94% vs 66%; P<.001), sharing CAUTI data with leadership (94% vs 70%; P=.014) and with nursing personnel (85% vs 56%, P=.003). However, fewer VA nursing homes reported having policies for appropriate catheter use (64% vs 81%; P=.004) and catheter insertion (83% vs 94%; P=.004).
Among nursing homes participating in an AHRQ-funded collaborative, VA and non-VA nursing homes differed in their approach to CAUTI prevention. Best practices from both settings should be applied universally to create an optimal infection prevention program within emerging integrated healthcare systems.
Various medications and devices are available for facilitation of emergent endotracheal intubations (EETIs). The objective of this study was to survey which medications and devices are being utilized for intubation by Canadian physicians.
A clinical scenario-based survey was developed to determine which medications physicians would administer to facilitate EETI, their first choice of intubation device, and backup strategy should their first choice fail. The survey was distributed to Canadian emergency medicine (EM) and intensive care unit (ICU) physicians using web-based and postal methods. Physicians were asked questions based on three scenarios (trauma; pneumonia; heart failure) and responded using a 5-point scale ranging from “always” to “never” to capture usual practice.
The survey response rate was 50.2% (882/1,758). Most physicians indicated a Macintosh blade with direct laryngoscopy would “always/often” be their first choice of intubation device in the three scenarios (mean 85% [79%-89%]) followed by video laryngoscopy (mean 37% [30%-49%]). The most common backup device chosen was an extraglottic device (mean 59% [56%-60%]). The medications most physicians would “always/often” administer were fentanyl (mean 45% [42%-51%]) and etomidate (mean 38% [25%-50%]). EM physicians were more likely than ICU physicians to paralyze patients for EETI (adjusted odds ratio 3.40; 95% CI 2.90-4.00).
Most EM and ICU physicians utilize direct laryngoscopy with a Macintosh blade as a primary device for EETI and an extraglottic device as a backup strategy. This survey highlights variation in Canadian practice patterns for some aspects of intubation in critically ill patients.
The Full-sky Astrometric Mapping Explorer (FAME) is designed to perform an all-sky, astrometric survey with unprecedented accuracy. It will create a rigid astrometric catalog of 4 × 107 stars with 5 < mV < 15. For bright stars, 5 < mV < 9, FAME will determine positions and parallaxes accurate to < 50 μas, with proper motion errors < 50 μas/yr. For fainter stars, 9 < mV < 15, FAME will determine positions and parallaxes accurate to < 500 μas, with proper motion errors < 500 μas/yr. It will also collect photometric data on these 4 × 107 stars in four Sloan Digital Sky Survey colors. NASA selected FAME to be one of five MIDEX missions funded for a concept study. In October 1999, NASA selected FAME for launch in 2004 as the MIDEX-4 mission in its Explorer program.
Impairments in key neuropsychological domains (e.g. working memory, attention) and social cognitive deficits have been implicated as intermediate (endo) phenotypes for bipolar disorder (BD), and should therefore be evident in unaffected relatives.
Neurocognitive and social cognitive ability was examined in 99 young people (age range 16–30 years) with a biological parent or sibling diagnosed with the disorder [thus deemed to be at risk (AR) of developing BD], compared with 78 healthy control (HC) subjects, and 52 people with a confirmed diagnosis of BD.
Only verbal intelligence and affective response inhibition were significantly impaired in AR relative to HC participants; the BD participants showed significant deficits in attention tasks compared with HCs. Neither AR nor BD patients showed impairments in general intellectual ability, working memory, visuospatial or language ability, relative to HC participants. Analysis of BD-I and BD-II cases separately revealed deficits in attention and immediate memory in BD-I patients (only), relative to HCs. Only the BD (but not AR) participants showed impaired emotion recognition, relative to HCs.
Selective cognitive deficits in the capacity to inhibit negative affective information, and general verbal ability may be intermediate markers of risk for BD; however, the extent and severity of impairment in this sample was less pronounced than has been reported in previous studies of older family members and BD cases. These findings highlight distinctions in the cognitive profiles of AR and BD participants, and provide limited support for progressive cognitive decline in association with illness development in BD.
We think we are in charge of our own lives. But psychology would have it that in actuality we are driven by subconscious forces not only beyond our conscious control but outside our full comprehension. We can modify these forces by rational control. But at heart we are carried along by currents over which we have limited influence.
This was surely so in my life. My parents assured me later that, at a time too early for me now to remember, well before my fourth birthday when I began formal musical training and long before I had engaged in any mathematical study whatever, I was showing interest in two main things: music and numbers. The interest in music is easy to understand: my parents were professional musicians and I was surrounded by music from the beginning. And I demanded to be taught to read music long before I evinced any interest in learning to read words. But the source of my early fascination with numbers is less obvious. Many of the people in my more extended family had been in technical professions, engineering in particular. But mathematics did not figure in my immediate family environment at all.
Even so, mathematics seized my imagination long before I was in a position to know anything about it in a formal way. Mathematical patterns of thought are of course the common property of everyone to some extent. They seem to be innate in the human mind. For me, and early on, this particular form of thought was one I wanted for my own above all others.
Some success later on in mathematical competitions encouraged me to think that I would be able to pursue the subject successfully as a profession. And being a university professor seemed to me in any case a natural choice of occupation, since it was my father's. But the point of origination was simply that mathematics seemed to me from the very start how I wanted to think.
These two interests, mathematics and music, both arising early in my life, never quite allowed the one to triumph over the other. Only in my early twenties when a practical choice was a necessity did I choose mathematics over music as my way to make a living. But music remains with me.
Children in care often have poor outcomes. There is a lack of evaluative
research into intervention options.
To examine the efficacy of Multidimensional Treatment Foster Care for
Adolescents (MTFC-A) compared with usual care for young people at risk in
foster care in England.
A two-arm single (assessor) blinded randomised controlled trial (RCT)
embedded within an observational quasi-experimental case–control study
involving 219 young people aged 11–16 years (trial registration: ISRCTN
68038570). The primary outcome was the Child Global Assessment Scale
(CGAS). Secondary outcomes were ratings of educational attendance,
achievement and rate of offending.
The MTFC-A group showed a non-significant improvement in CGAS outcome in
both the randomised cohort (n = 34, adjusted mean
difference 1.3, 95% CI −7.1 to 9.7, P = 0.75) and in the
trimmed observational cohort (n = 185, adjusted mean
difference 0.95, 95% CI −2.38 to 4.29, P = 0.57). No
significant effects were seen in secondary outcomes. There was a possible
differential effect of the intervention according to antisocial
There was no evidence that the use of MTFC-A resulted in better outcomes
than usual care. The intervention may be more beneficial for young people
with antisocial behaviour but less beneficial than usual treatment for