Digital automatic gain amplifier

A circuit is described for adjusting the amplitude of a reference signal to a predetermined level so as to permit subsequent data signals to be interpreted correctly. The circuit includes an operational amplifier having a feedback circuit connected between an output terminal and an input terminal; a bank of relays operably connected to a plurality of resistors; and a comparator comparing an output voltage of the amplifier with a reference voltage and generating a compared signal responsive thereto. Means is provided for selectively energizing the relays according to the compared signal from the comparator until the output signal from the amplifier equals to the reference signal. A second comparator is provided for comparing the output of the amplifier with a second voltage source so as to illuminate a lamp when the output signal from the amplifier exceeds the second voltage

Microcomputerized electric field meter diagnostic and calibration system

A computerized field meter calibration system which includes an apparatus for testing the calibration of field meters normally utilized for measuring electromagnetic field potentials is described. A reference voltage is applied to the field meter for causing signals to be produced on the output terminals thereof. A bank of relays is provided for selectively connecting output terminals of the field meter to a multiplexer by means of a digital voltmeter and an oscilloscope. A frequency-shift-keyed receiver is also connected to one of the terminals of the field meter for transmitting and converting a frequency shift keyed signal to a digital signal which is, subsequently, applied to the multiplexer

Event Rate for Extreme Mass Ratio Burst Signals in the LISA Band

Stellar mass compact objects in short period orbits about a $10^{4.5}$--$10^{7.5}$ solar mass massive black hole (MBH) are thought to be a significant continuous-wave source of gravitational radiation for the ESA/NASA Laser Interferometer Space Antenna (LISA) gravitational wave detector. However, these extreme mass-ratio inspiral sources began in long-period, nearly parabolic orbits that have multiple close encounters with the MBH. The gravitational radiation emitted during these close encounters may be detectable by LISA as a gravitational wave burst if the characteristic passage timescale is less than $10^5$ seconds. Scaling a static, spherical model to the size and mass of the Milky Way bulge we estimate an event rate of ~ 15 per year for such burst signals, detectable by LISA with signal-to-noise greater than five, originating in our galaxy. When extended to include Virgo cluster galaxies our estimate increases to a gravitational wave burst rate of ~ 18. We conclude that these extreme mass-ratio burst sources may be a steady and significant source of gravitational radiation in the LISA data streams.Comment: 4 pages, minor revisions. Accepted for ApJ Letter

An automatic lightning detection and photographic system

Conventional 35-mm camera is activated by an electronic signal every time lightning strikes in general vicinity. Electronic circuit detects lightning by means of antenna which picks up atmospheric radio disturbances. Camera is equipped with fish-eye lense, automatic shutter advance, and small 24-hour clock to indicate time when exposures are made

Criminal Prosecution of Bank Personnel Under the Misapplication Statute: The Proper Mens Rea Standard for Establishing Intent

This Recent Development advocates legislative adoption of a new Misapplication Statute as a long range solution to the courts\u27continued debate over the appropriate mens rea standard and judicial adoption of a uniform approach as a short run alternative. Part II of this Recent Development traces the various mens rea standards that courts have applied under the Misapplication Statute. Part III discusses the current confusion over the appropriate section 656 mens rea standard by looking at three recent circuit court decisions.\u27 Part IV advocates the adoption of a new Misapplication Statute similar to the approach that the National Com-mission on Reform of Criminal Laws suggests in its proposed revisions to Title 18. This approach delineates three categories of offenses, each corresponding to a different level of culpability and punishment. Part IV also suggests that until Congress drafts a new Misapplication Statute, the courts should establish a uniform standard for section 656 mens rea that restricts prosecution only to defendants who possess the traditional mens rea of knowledge

The impact of risk management practice upon the implementation of recovery-oriented care in community mental health services: a qualitative investigation

Background: Recovery-oriented care has become guiding principle for mental health policies and practice in the UK and elsewhere. However, a pre-existing culture of risk management practice may impact upon the provision of recovery-oriented mental health services. Aims: To explore how risk management practice impacts upon the implementation of recovery-oriented care within community mental health services. Method: Semi-structured interviews using vignettes were conducted with 8 mental health worker and service user dyads. Grounded theory techniques were used to develop explanatory themes. Results: Four themes arose: 1) recovery and positive risk taking; 2) competing frameworks of practice; 3) a hybrid of risk and recovery; 4) real-life recovery in the context of risk. Discussion: In abstract responses to the vignettes, mental health workers described how they would use a positive risk taking approach in support of recovery. In practice, this was restricted by a risk-averse culture embedded within services. Mental health workers set conditions with which service users complied to gain some responsibility for recovery. Conclusion: A lack of strategic guidance at policy level and lack of support and guidance at practice level may result in resistance to implementing ROC in the context of RMP. Recommendations are made for policy, training and future research

The influence of ethnic group composition on focus group discussions

BACKGROUND: Focus groups are commonly used to explore participants' experiences in health and social care research. Although it is suggested that having demographically homogenous groups may help put participants at ease, the evidence is sparse.The aims of the paper are to: explore the impact of relative ethnic homogeneity and heterogeneity of focus group participants on the group discussions; improve understanding of homogeneity and heterogeneity in focus groups; suggest ways to operationalise concepts such as being 'more comfortable' with other focus group participants. METHOD: Digitally recorded focus groups were undertaken with family carers of stroke survivors and were later transcribed and analysed using framework analysis. Groups were designated as more or less ethnically homogenous. More homogenous groups included, for example, only White British or Asian Indian participants whilst more heterogeneous groups comprised a mixture of, for example, Asian, White British and Black Caribbean participants. RESULTS: Forty-one carers participated in seven focus groups. Analysis revealed differences in discussions around ethnicity between the more or less ethnically homogenous groups. For example, participants in more ethnically homogenous focus groups were more likely to say ethnicity might influence perceptions of social care services. On the other hand, more heterogeneous groups emphasised similarity in carers' experiences, irrespective of ethnicity. Participants in the more homogenous groups were also more likely to make potentially controversial comments relating to ethnic differences. Additionally they appeared to be more at ease with each other discussing the topic. For example, they spontaneously mentioned ethnic differences earlier in these groups.In contrast, analysis of topics not specifically related to ethnicity, such as the difficult experiences of being a carer, produced no discernible patterns when comparing more and less homogenous focus groups. CONCLUSION: Considerations around focus group participant demographic homogeneity and heterogeneity are complex and these terms may be most usefully applied only in relative terms.Data derived from more homogenous groups complement data from more heterogeneous groups providing different perspectives. Depending on the focus of the discussion, having characteristics in common, such as being a carer can override other differences

The experience of long stay in high and medium secure psychiatric hospitals in England: qualitative study of the patient perspective

Background: Some forensic patients in England remain in secure care for long, possibly unnecessarily prolonged, periods, raising significant ethical and resource issues. Research focused on the patients in secure care has examined quality of life and service provision but not the perspectives of patients experiencing long stays. This study explored how long stay patients experience secure care, what factors they felt influenced long stay, and its impact upon treatment engagement and motivation to progress. Methods: Embedded within a larger epidemiological study, we conducted semi-structured interviews with a purposive sample of forty long stay patients from two high and six medium secure hospitals. Long stay was defined as a 5 years stay in medium secure care or 10 years in high secure care, or 15 years in a combination of high and medium secure. Transcripts were subject to thematic analysis, and narrative analysis at individual case level to explore the relationship between emergent themes. Results: Four themes emerged illustrating participants’ attribution, outlook, approach, and readiness for change. A typology of four long stay stances was developed (dynamic acceptance, dynamic resistance, static acceptance, static resistance). These illustrate differences in the extent to which participants believed being in secure care helped them to get better, and actively work towards progression and leaving secure care. There were considerable differences in how patients adopting these stances attributed the reasons for their long stay, they viewed their future, and their motivation to progress. Negative perceptions arose from excessive restrictions, treatment repetition and changes in therapeutic relationships, leading some patients to exhibiting tokenistic engagement and low motivation to progress. Conclusions: Planning care for long stay patients in secure psychiatric settings should take account of the differing stances patient’s adopt towards engagement and progression. Service providers should be mindful of these stances and provide patients with individualised opportunities to progress through the secure care treatment pathway, avoiding treatment repetition and maintaining continuity in key professional relationships. Refocusing on quality of life may be appropriate for some long-term patients who are unwilling or unable to move on. For some long-term patients, purpose designed long stay setting may be appropriate

Control of supersonic wind-tunnel noise by laminarization of nozzle-wall boundary layer

One of the principal design requirements for a quiet supersonic or hypersonic wind tunnel is to maintain laminar boundary layers on the nozzle walls and thereby reduce disturbance levels in the test flow. The conditions and apparent reasons for laminar boundary layers which have been observed during previous investigations on the walls of several nozzles for exit Mach numbers from 2 to 20 are reviewed. Based on these results, an analysis and an assessment of nozzle design requirements for laminar boundary layers including low Reynolds numbers, high acceleration, suction slots, wall temperature control, wall roughness, and area suction are presented