Focusing on out-of-focus : assessing defocus estimation algorithms for the benefit of automated image masking

Acquiring photographs as input for an image-based modelling pipeline is less trivial than often assumed. Photographs should be correctly exposed, cover the subject sufficiently from all possible angles, have the required spatial resolution, be devoid of any motion blur, exhibit accurate focus and feature an adequate depth of field. The last four characteristics all determine the " sharpness " of an image and the photogrammetric, computer vision and hybrid photogrammetric computer vision communities all assume that the object to be modelled is depicted " acceptably " sharp throughout the whole image collection. Although none of these three fields has ever properly quantified " acceptably sharp " , it is more or less standard practice to mask those image portions that appear to be unsharp due to the limited depth of field around the plane of focus (whether this means blurry object parts or completely out-of-focus backgrounds). This paper will assess how well-or ill-suited defocus estimating algorithms are for automatically masking a series of photographs, since this could speed up modelling pipelines with many hundreds or thousands of photographs. To that end, the paper uses five different real-world datasets and compares the output of three state-of-the-art edge-based defocus estimators. Afterwards, critical comments and plans for the future finalise this paper

Recovery kinetics of winter stressed conifers: The effects of growth light environment, extent of the season, and species.

Evergreens undergo a dramatic reduction in their maximal photochemical efficiency (measured as Fv/Fm) during winter, which is largely due to increases in a sustained form of thermal energy dissipation. Upon removing winter-stressed leaves to room temperature and low light, Fv/Fm recovers over several days and can include both a rapid phase (reversing in minutes) and a slow phase (reversing over days). Both phases are associated with reversal of sustained energy dissipation. Preliminary examination of recovery of evergreens monitored in January in Minnesota showed an absence of the rapid component to recovery. Our goal was to monitor recovery kinetics of sun and shade evergreens in Minnesota throughout winter in order to assess whether the rapid phase of recovery exists early in the winter and converts to the slowly reversible form as winter progresses. Four species of conifers (sun and shade needles) were monitored during the winter of 2007/08: eastern white pine (_Pinus strobus_ L.), balsam fir [_Abies balsamea_ (L.) P. Mill], _Taxus cuspidata_ (L.) and blue spruce (_Picea pungens_ Engelm.). Fv/Fm was measured on dark acclimated needles in the field, twigs were collected, brought indoors and maintained at room temperature and low light where Fv/Fm was monitored for six days. 

The results demonstrated that all species, and both sun and shade needles, showed a rapidly reversible component to recovery in early winter (November). In the sun needles this component was rarely present later in the season, while in the shade needles it was present (although only a small fraction of the total sustained energy dissipation) on most days monitored during winter. The slowly reversible component to sustained energy dissipation was present in both sun and shade needles of all species beginning in November. In all cases, shade needles recovered significantly faster than sun needles. There was a significant slowing of recovery (the slowly reversible component) as winter progressed in both sun and shade needles, and significant differences between species in their recovery response. The results indicate a relatively small contribution of the rapidly reversible component of sustained energy dissipation compared with earlier studies on evergreens growing in the milder winter conditions of Colorado. The results also provide evidence that the rapid component to recovery diminishes as the season progresses, particularly in needles growing in full sun where the slowly reversible component of sustained energy dissipation accounts for most or all of the observed sustained energy dissipation. 
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When staff handle staph : user-driven versus expert-driven communication of infection control guidelines

Health care-associated infections cause thousands of preventable deaths each year. Therefore, it is crucial that health care workers (HCWs) adhere to infection control guidelines. Although most HCWs are aware of the rationale for guidelines, adherence is generally poor, which might be caused by the guidelines’ expert-driven character. Whereas traditional, paper-based guidelines have a strong focus on scientific validation, regulation, and legislation, HCWs’ information need is rather action-oriented.\ud \ud Based on extensive user-centered research involving HCWs (comprised of eight studies including Card Sort, scenario testing with thinking aloud, prototyping, interviewing, etc), a multimodal website was developed that presents evidence-based guidelines as answers to questions that reflect HCWs’ practical informational needs. \ud \ud Evaluation studies showed that the website outperformed the traditional, paper-based guidelines with regard to efficiency (time for task completion decreased significantly from six to two minutes), effectiveness (successful task completion rate increased significantly from 50% to 90%), and user satisfaction. The website appeared to ‘empower’ HCWs since it allowed them to take decisions for daily work practice, and thereby reduced infection control professionals’ workload. \ud \ud Since a website in itself is not enough to change HCWs’ behavioral intention to adhere to the guidelines, the factors that affect adoption of the website in daily work practice were investigated next to the determinants of intention to adhere. These factors were considered during the implementation phase of the website. \ud \ud The studies that together composed the user-centered design process of the website are described in a dissertation (thesis defense October 2nd, 2009). This dissertation provides the methodological steps and design principles necessary to communicate user-driven guidelines via a website and suggests how to optimally implement this website in daily work practice, in order to enhance effective and efficient risk- and crisis communication. Methicillin Resistant Staphylococcus aureus (also known as “hospital bacteria”) served as a case study for this dissertation research, but the thesis might also serve as a manual for the communication of guidelines regarding all types of infectious diseases, such as Mexican flu (H1N1)). This is subject of future research.\ud \ud Furthermore, future studies will concentrate on the development of e-learning strategies for HCWs and incorporating an advanced dialogue system into the website

Ramp Type HTS Josephson Junctions with PrBaCuGaO Barriers

Ramp type Josephson junctions have been fabricated using DyBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// as electrode material and PrBa/sub 2/Cu/sub 3-x/Ga/sub x/O/sub 7-/spl delta// with x=0, 0.10 and 0.40 as junction barriers. Barrier thickness lie between 6-30 nm. Several junctions without barrier were made in order to find ways to minimize the damage of the ramp interface. In total about 40 chips were fabricated each containing several junctions and their I-V characteristics measured for various temperatures down to 4.2 K. Only those junctions showing clear RSJ-like curves were selected to be analyzed. In some cases we also measured I/sub c/ as a function of a small applied field and obtained a clear Fraunhofer pattern, but there is a tendency to flux trapping as evidenced by LTSEM. It was found at 4.2 K that the critical current density J/sub c/ scales with the specific resistance R/sub n/A as J/sub c/=C/sub bar/(R/sub n/A)/sup -m/ (m=1.8/spl plusmn/0.5). The barrier material dependent constant C/sub bar/ increases with x, whereas, for a given d, J/sub c/ is constant and R/sub n/A increase