Fabrication and characterization of micromachined rectangularwaveguide components for use at millimeter-wave and terahertzfrequencies

The fabrication and characterization of micromachined reduced-height air-filled rectangular waveguide components suitable for integration is reported in this paper. The lithographic technique used permits structures with heights of up to 100 μm to be successfully constructed in a repeatable manner. Waveguide S-parameter measurements at frequencies between 75-110 GHz using a vector network analyzer demonstrate low loss propagation in the TE₁₀ mode reaching 0.2 dB per wavelength. Scanning electron microscope photographs of conventional and micromachined waveguides show that the fabrication technique can provide a superior surface finish than possible with commercially available components. In order to circumvent problems in efficiently coupling free-space propagating beams to the reduced-height G-band waveguides, as well as to characterize them using quasi-optical techniques, a novel integrated micromachined slotted horn antenna has been designed and fabricated, E-, H-, and D-plane far-field antenna pattern measurements at different frequencies using a quasi-optical setup show that the fabricated structures are optimized for 180-GHz operation with an E-plane half-power beamwidth of 32° elevated 35° above the substrate, a symmetrical H-plane pattern with a half-power beamwidth of 23° and a maximum D-plane cross-polar level of -33 dB. Far-field pattern simulations using HFSS show good agreement with experimental results     

Perspectives on electron cryo-tomography of vitreous cryo-sections

A major objective of modern structural biology is to appreciate the cellular organization by elucidating the spatial arrangement of macromolecular complexes within a cell. Cryogenic sample preparation, combined with cryo-ultramicrotomy, enables large cells and pieces of biological tissues to be thinned for electron cryo-tomography, which provides a three-dimensional view of the biological sample. There are, however, limitations associated with the technique that must be realized, addressed and overcome for the procedure to become mainstream. Here, we provide perspectives on the continued advancements in cryogenic sample preparation for vitreous cryo-sectioning, image collection and post-image processing that have expanded the attainable information limit within the three-dimensional reconstructions of cells and pieces of biological tissues.     

Characteristics of single vehicle rollover fatalities in three Australian states (2000-2007)

An analysis of 2000–2007 single vehicle rollover fatalities in three Australian states was carried out using data from the Australian National Coroners Information System. In this paper, successive selection criteria were applied to the initial dataset to analyse:

• - 

  Occupant fatalities in single passenger car crashes (1743 cases),

• - 

  Occupant fatalities in single passenger car rollovers (474 cases),

overall, rollovers accounted for 35% of all occupant fatalities in a single vehicle transport injury event. For these fatalities, the occupant was ejected or stayed contained in equal proportions. However, results showed strong disparities between the more urban and densely populated states of New South Wales and Victoria, compared to the Northern Territory in terms of crash type distribution and containment of the occupant. Differences were also found in rollover initiation, speed at initiation and number of turns. Overall, the strongest association of fatal neck/thoracic spine injuries with head injuries was found for the contained, restrained occupant. This analysis of single vehicle rollover fatalities is consistent with previous findings. It also shows that in Australia, strategies for rollover injury risk mitigation will need to take into account a broad range of characteristics to be effective.     

Lake responses following lanthanum-modified bentonite clay (Phoslock) application: An analysis of water column lanthanum data from 16 case study lakes

Phoslock^® is a lanthanum (La) modified bentonite clay that is being increasingly used as a geo-engineering tool for the control of legacy phosphorus (P) release from lake bed sediments to overlying waters. This study investigates the potential for negative ecological impacts from elevated La concentrations associated with the use of Phoslock^® across 16 case study lakes. Impact-recovery trajectories associated with total lanthanum (TLa) and filterable La (FLa) concentrations in surface and bottom waters were quantified over a period of up to 60 months following Phoslock^® application. Both surface and bottom water TLa and FLa concentrations were <0.001 mg L⁻¹ in all lakes prior to the application of Phoslock^®. The effects of Phoslock^® application were evident in the post-application maximum TLa and FLa concentrations reported for surface waters between 0.026 mg L⁻¹–2.30 mg L⁻¹ and 0.002 mg L⁻¹ to 0.14 mg L⁻¹, respectively. Results of generalised additive modelling indicated that recovery trajectories for TLa and FLa in surface and bottom waters in lakes were represented by 2nd order decay relationships, with time, and that recovery reached an end-point between 3 and 12 months post-application. Recovery in bottom water was slower (11–12 months) than surface waters (3–8 months), most probably as a result of variation in physicochemical conditions of the receiving waters and associated effects on product settling rates and processes relating to the disturbance of bed sediments. CHEAQS PRO modelling was also undertaken on 11 of the treated lakes in order to predict concentrations of La³⁺ ions and the potential for negative ecological impacts. This modelling indicated that the concentrations of La³⁺ ions will be very low (<0.0004 mg L⁻¹) in lakes of moderately low to high alkalinity (>0.8 mEq L⁻¹), but higher (up to 0.12 mg L⁻¹) in lakes characterised by very low alkalinity. The effects of elevated La³⁺ concentrations following Phoslock^® applications in lakes of very low alkalinity requires further evaluation. The implications for the use of Phoslock^® in eutrophication management are discussed.     

Gynecologic disorders in women with Ehlers-Danlos syndrome

OBJECTIVE: We characterized the population with Ehlers-Danlos syndrome with regard to genital prolapse, urinary incontinence, and other gynecologic disorders. METHODS: Forty-one adult women who had registered for a first-ever Ehlers-Danlos multidisciplinary clinic participated in the study. Each had a comprehensive standardized evaluation, including gynecologic history, physical examination, urodynamic testing, and physical therapy evaluation. Qualitative and quantitative data were analyzed to determine means for various gynecologic disorders of Ehlers-Danlos syndrome. RESULTS: The frequencies of incontinence complaints (59%), endometriosis (27%), dyspareunia (57%), and previous hysterectomy (44%) were higher than expected for a population with a mean age of 41 years. Incontinence could not be demonstrated objectively. Prolapse was diagnosed in 12 (29.3%). CONCLUSIONS: Careful attention should be paid to women with Ehlers-Danlos syndrome because of an association with many gynecologic complaints. Women with Ehlers-Danlos syndrome should be questioned regarding incontinence, genital prolapse, endometriosis, and dyspareunia.     

The impact of rapid release cycles on the integration delay of fixed issues

The release frequency of software projects has increased in recent years. Adopters of so-called rapid releases—short release cycles, often on the order of weeks, days, or even hours—claim that they can deliver fixed issues (i.e., implemented bug fixes and new features) to users more quickly. However, there is little empirical evidence to support these claims. In fact, our prior work shows that code integration phases may introduce delays for rapidly releasing projects—98% of the fixed issues in the rapidly releasing Firefox project had their integration delayed by at least one release. To better understand the impact that rapid release cycles have on the integration delay of fixed issues, we perform a comparative study of traditional and rapid release cycles. Our comparative study has two parts: (i) a quantitative empirical analysis of 72,114 issue reports from the Firefox project, and a (ii) qualitative study involving 37 participants, who are contributors of the Firefox, Eclipse, and ArgoUML projects. Our study is divided into quantitative and qualitative analyses. Quantitative analyses reveal that, surprisingly, fixed issues take a median of 54% (57 days) longer to be integrated in rapid Firefox releases than the traditional ones. To investigate the factors that are related to integration delay in traditional and rapid release cycles, we train regression models that model whether a fixed issue will have its integration delayed or not. Our explanatory models achieve good discrimination (ROC areas of 0.80–0.84) and calibration scores (Brier scores of 0.05–0.16) for rapid and traditional releases. Our explanatory models indicate that (i) traditional releases prioritize the integration of backlog issues, while (ii) rapid releases prioritize issues that were fixed in the current release cycle. Complementary qualitative analyses reveal that participants’ perception about integration delay is tightly related to activities that involve decision making, risk management, and team collaboration. Moreover, the allure of shipping fixed issues faster is a main motivator for adopting rapid release cycles among participants (although this motivation is not supported by our quantitative analysis). Furthermore, to explain why traditional releases deliver fixed issues more quickly, our participants point out the rush for integration in traditional releases and the increased time that is invested on polishing issues in rapid releases. Our results suggest that rapid release cycles may not be a silver bullet for the rapid delivery of new content to users. Instead, our results suggest that the benefits of rapid releases are increased software stability and user feedback.     

A stepped-frequency delta-K microwave radar for oceanographicstudies

A stepped-frequency delta-K (SFDK) radar has been developed to remotely sense ocean surface characteristics. This C-band radar uses frequency diversity and real-time signal processing for improved ΔK measurements. It is shown how frequency diversity can be implemented to enhance the energy of the resonant peak of the cross-product spectrum relative to the background energy. This feature is essential for making real-time measurements of resonant peak frequency over extended time periods. SFDK was used in a month-long field experiment at North Truro, MA. The results presented show that the phase velocity of ocean surface waves could be precisely measured 87% of the time     

Scanning electron microscope sizing of airborne fibre samples: a preliminary investigation into the effects of the variable inclination of fibres to filter surfaces

High infant mortality, regional differences, and the remaining likewise differences over a long time period were already known in the last century. Multifactorial models were discussed to explain this phenomenon and great importance was given to social factors in these societies. We analysed two populations from the same region in South Germany with a high infant mortality in the 19th century. The environment (e.g. climate, rural regions) was similar, the two villages had small differences in population size. Since the end of the 16th century the two villages have belonged to different denominations, one village is catholic, the other protestant, and there are no marriages between them (until today). All data we analysed, came from parochial registers. The results show that in all decades of the last century the infant mortality was higher in the catholic population (about 450) than in the protestant population (ca. 350). We can find these differences on the microlevel, too. The comparison of families (marriages concluded 1840-1849 and 1850-1859) show the same effect. The analysis of the influences on the number of children per family and the age of the mother at birth of their children to infant mortality confirm the hypothesis that social factors, strongly influenced by the denomination, are the main factors to explain the differences.