Are Diamonds a MEMS' Best Friend?

Next-generation military and civilian communication systems will require technologies capable of handling data/ audio, and video simultaneously while supporting multiple RF systems operating in several different frequency bands from the MHz to the GHz range [1]. RF microelectromechani-cal/nanoelectromechanical (MEMS/NEMS) devices, such as resonators and switches, are attractive to industry as they offer a means by which performance can be greatly improved for wireless applications while at the same time potentially reducing overall size and weight as well as manufacturing costs.     

Streamflow alteration and habitat ramifications for a threatened fish species in the Central United States

In the Central United States, the Arkansas darter (Etheostoma cragini) is listed as a threatened fish species by the State of Kansas. Survival of the darter is threatened by loss of habitat caused by changing streamflow conditions, in particular flow depletion. Future management of darter populations and habitats requires an understanding of streamflow conditions and how those conditions may have changed over time in response to natural and anthropogenic factors. In Kansas, streamflow alteration was assessed at 9 U.S. Geological Survey streamgages in 6 priority basins with no pronounced long‐term trends in precipitation. The assessment was based on a comparison of observed (O) and predicted expected (E) reference conditions for 29 flow metrics. The O/E results indicated a likely or possible diminished flow condition in 2 basins; the primary cause of which is groundwater‐level declines resulting from groundwater pumping for irrigated agriculture. In these 2 basins, habitat characteristics adversely affected by flow depletion may include stream connectivity, pools, and water temperature. The other 4 basins were minimally affected, or unaffected, by flow depletion and therefore may provide the best opportunity for preservation of darter habitat. Through the O/E analysis, anthropogenic streamflow alteration was quantified and the results will enable better‐informed decisions pertaining to the future management of darters in Kansas.     

External review for promotion and tenure in schools of nursing

A literature review conducted for a 1989 article on assessing the quality of life in surgical studies revealed that quality of life was more often mentioned than measured. Few authors reported the use of known, standardized scales. The objective of this study was to determine if and to what extent this situation has changed. A MEDLINE search of surgical studies published between 1989 and 1995 produced over 277 abstracts of surgical studies containing the words "quality of life." The abstracts were studied in three time periods: 1989-1990, 1991-1992 and 1993-1995. Findings indicated that the use of the term "quality of life" increased markedly over the study period, and studies using standardized measures escalated from 27.4% in 1989-1990 to 48.3% in 1993-1995. Those abstracts not stating how quality of life was assessed decreased from 48.4% in the early period to 21.7% in the last period. Of the abstracts reporting studies that used quality of life measures, 33% came from cancer studies, 21.7% from cardiovascular or respiratory studies, 14.8% from gastroenterology studies, 13.4% from nephrology studies and 6.1% from orthopedic studies. Surgical investigators selected a variety of global measures of quality of life as well as disease-specific instruments. The abstracts also revealed that surgeons are using quality-of-life assessment to monitor patients over time, to help select patients for surgery, to determine the effect of surgical treatment and for making policy decisions. Notwithstanding the limitations of this project, there is evidence in the literature that surgeons are increasingly willing to assess the impact of the surgical interventions by quality-of-life measures and are becoming more familiar with the diverse measures used to assess quality of life.     

Definition of the Linear Region of X-Ray -Induced Cable Response

Cable response to X-rays is linear with incident fluence, provided the deposited charge in cable dielectrics is directly proportional to the X-ray flux. To estimate the level at which the linear region ends, we discuss three nonlinear processes that modify the deposited charge profile in a hypothetical cable model: field-limiting in vacuum gaps, ionization effects in air-filled gaps, and radiation-induced dielectric conductivity. The exact level at which limiting of the Norton driver in an elemental length of cable begins depends on the cable geometry and the X-ray source. Estimates of the onset of nonlinearities caused by field-limiting and by dielectric conductivity are found in terms of cable and source parameters. With air-filled gaps, the Norton driver is always nonlinear. In addition to limiting of the Norton drivers, the load response of a long cable may be limited because propagating currents are attenuated by the induced conductivity of the bulk of the dielectric.     

Designing against a class of algebraic attacks on symmetric block ciphers

Recently, Courtois and Pieprzyk proposed a class of algebraic attacks on symmetric block ciphers that takes advantage of a previously-unexploited property of substitution boxes, or s-boxes, in the round function. This paper gives a brief overview of this ``overdefined system of equations' (OSE) attack and shows how the attack may be avoided through the use of round functions constructed according to the CAST design procedure. Such round functions contain a variety of protection mechanisms, including s-boxes of large dimension, a circular key-dependent rotation step, and combinations of operators from different algebraic groups.     

The efficacy of oral appliances in the treatment of persistent sleep apnea after uvulopalatopharyngoplasty

Twenty-four patients who failed uvulopalatopharyngoplasty (UPPP) for obstructive sleep apnea (OSA) had an adjustable oral (Herbst) appliance made to treat the persistent apnea. Six patients discontinued the device prior to sleep evaluation. Eighteen patients had polysomnographic evaluations at baseline, post-UPPP, and with the Herbst appliance in place. The apnea-hypopnea index baseline (AHI) and arterial oxygen saturation (SaO2) nadir were 42.3+/-6.1 and 83.6+/-1.8%, respectively. There was no significant change in either parameter with surgery. With the oral appliance, the AHI fell to 15.3+/-4.4 (p < or = 0.01) and the SaO2 nadir increased to 87.9+/-1.2% (p < or = 0.05). Ten of the patients had control of the OSA with the Herbst appliance with a fall in the AHI to < 10. There were, in addition, two partial responders as defined by an AHI of <20 and a >50% fall in AHI compared with baseline and post-UPPP values. All but one of the responders and partial responders had complete resolution of subjective symptoms of daytime sleepiness with the appliance. An adjustable oral appliance appears to be an effective mode of therapy to control OSA after an unsuccessful UPPP.     

Effects of plant growth regulators on locusts and cotton stainer bugs

Gibberellic acid is a necessary dietary constituent for normal fast maturation in the desert locust. Diets short of gibberellins, such as senescent vegetation, produce a state of adult diapause. The synthetic plant growth retardant (2-chloroethyl)-trimethylammonium chloride (CCC), either injected into locusts or fed to them as a separate dietary constituent, inhibits meiosis and so retards or prevents sexual maturation. Once this stage of gametogenesis has passed (late in nymphal life) CCC appears to have no further effect, but a single injection just before the onset of meiosis will sterilise locusts completely. Cotton stainers provided with a solution of CCC in their drinking water during the same period of larval life show impaired reproductive function and produce deformed offspring. CCC acts directly upon the insects, quite apart from any secondary effect produced by the altered physiology of the food plant.     

Optical properties of disperse-red-1-doped nematic liquid crystal

We report on the optical properties of nematic liquid crystal cells containing the commercially available liquid crystal E7 doped with the azo dye Disperse Red 1 at concentrations ranging from 0.3% to 1.0%. From polarized absorption measurements an order parameter of S=0.569 was obtained, thus showing that the dye molecules align themselves very well with the liquid crystal's director axis. Optical index gratings were written in the material by overlapping two coherent laser beams at 532 nm. Self-diffraction of the writing beams and diffraction of a probe beam at 670 nm were measured. First-order self-diffraction efficiencies and rise times were found to be linearly dependent upon the dye concentration with a maximum efficiency of 3.29% and a minimum rise time of 10.6 ms. The non-linear index coefficient, n ₂, was calculated to be 7.6 × 10^-3cm²W^-1. The data are consistent with a grating formation based on trans–cis photoisomerism of the dye molecules that leads to a reorientation of the liquid crystal phase. These photonic devices are functional without the application of any external field, they are easily prepared, and have lifetimes in excess of two years without any indication of degradation when stored at ambient temperature.     

Hierarchical time-based information release

Rapid distribution of newly released confidential information is often impeded by network traffic jams, especially when the confidential information is either crucial or highly prized. This is the case for stock market values, blind auction bidding amounts, many large corporations'strategic business plans, certain news agencies'timed publications, and some licensed software updates. Hierarchical time-based information release (HTIR) schemes enable the gradual distribution of encrypted confidential information to large, distributed, (potentially) hierarchically structured user communities, and the subsequent publication of corresponding short decryption keys, at a predetermined time, so that users can rapidly access the confidential information. This paper presents and analyzes the efficiency of a novel HTIR scheme. Deholo Nali holds a M.Sc. in mathematics and a Ph.D. in Computer Science from the University of Ottawa, Canada. In the past, he worked for two years as a software developer and pursued research in the design and analysis of identity-based cryptographic protocols. His research interests now include identity theft and graphical password authentication.