Experimental results on adiabatic coupling into SOI photonic Crystal coupled-cavity waveguides

The experimental implementation of an adiabatic coupling technique for efficient coupling between photonic crystal single-line defect waveguides and coupled-cavity waveguides is reported. The samples were fabricated in a silicon-on-insulator substrate using 248-nm-deep ultraviolet lithography. Experimental results are compared with three-dimensional (3-D) finite-difference time-domain simulations. Furthermore, the discrepancies between two-dimensional and 3-D simulation results are analyzed.     

Small bowel transplantation: current progress and clinical application

Total parenteral nutrition (TPN) is used routinely to maintain patients with the Short Bowel Syndrome (SBS). Until recently, TPN has been the only available therapeutic modality for patients with SBS. Currently, it is the treatment of choice for such individuals and occasionally, when the loss of bowel is extensive, it may be the only way of maintaining life. Unfortunately, TPN is expensive and markedly restrains an individual's lifestyle. Despite the overall success of TPN, the numerous risks associated with its use and the many complications of having an intravenous indwelling for years have served as the stimulus for alternative treatments such as small bowel transplantation (SBT). The first attempts at small bowel transplantation in clinical medicine were by Detterling almost 25 years ago. Patient death or graft loss in these early attempts was caused by the failure to control graft rejection and/or the inability to prevent Graft Versus Host Disease (GVHD). A stimulus for renewed clinical interest in SBT was provided by Starzl et al in 1988 with a report of prolonged graft survival without graft rejection or GVHD in a patient who was the recipient of a multivisceral graft consisting of the entire small bowel and other abdominal organs. Since 1964, 78 Small Bowel transplants have been performed in humans. Several variations of the multivisceral procedure in which the liver and the small bowel constitute the major components of the graft were adopted. The longest survival has been in a child who is still alive with a working graft for more than two years, as reported by Goulet from Paris in 1989. The introduction in SBT of the new immunosuppressive agent FK 506 had provided results which are superior to those achieved with Cyclosporine A (CsA). This latter observation prompted the Pittsburgh group to initiate a large series of isolated and composite intestinal grafts. The remarkable results have demonstrated the clinical utility of intestinal transplantation. This paper will try to summarize the history of the small bowel transplantation until the end of the year 1992, with the current progress in use today.     

Is Relevance Relevant? Market,Science, and War: Discourses of Search Engine Quality

In the face of rising controversy about search engine results—that they are too restrictive, too comprehensive, lacking in certain areas, over-represented in others—this article presents the results of in-depth interviews with search engine producers, examining their conceptions of search engine quality and the implications of those conceptions. Structuration theory suggests that the cultural schemas that frame these discourses of quality will be central in mobilizing resources for technological development. The evidence presented here suggests that resources in search engine development are overwhelmingly allocated on the basis of market factors or scientific/technological concerns. Fairness and representativeness, core elements of the journalists' definition of quality media content, are not key determiners of search engine quality in the minds of search engine producers. Rather, alternative standards of quality, such as customer satisfaction and relevance, mean that tactics to silence or promote certain websites or site owners (such as blacklisting, whitelisting, and index "cleaning") are seen as unproblematic.     

From dust till drawn

We present a system for drawing pastel media in real-time as an effective alternative to most existing digital solutions that basically allow for drawing arbitrary strokes in a particular style. Our approach is focused on the simulation of the natural material itself and on its interaction with the drawing surface and the drawing tool. Upon free-form drawing, a bidirectional transfer of pigment takes place. In one direction, the paper surface is dusted with new pigment particles broken off the tip (i.e., the end of the drawing tool). A large part of these particles will be deposited or blended together with previously deposited ones whereas the remainder does not contribute to the drawing and is blown off. On the other hand, a certain amount of previously deposited pigment is scraped off and picked up again soiling the tip. This is noticeable in the next strokes to be drawn. Furthermore, both the tip and the paper surface are subject to weathering depending on the exerted pressure and friction of the drawing tool, and the bumpiness of the paper. As a result, the paper surface becomes slightly damaged, limiting the deposition of new pigment. The tip, on the other hand, becomes blunt making new strokes wider. From a stylistic point of view, similarly to traditional drawings our results convey the artists’ characteristics (e.g., the way of wielding the brush, skillfulness, feeling for the medium). Therefore, we believe that our system allows an artist to create realistically looking pastel images without losing his/her personal touch.     

Six Synthesis Methods for Reversible Logic

The (2 ^w )! reversible transformations on w wires, i.e. reversible logic circuits with w inputs and w outputs, together with the action of cascading, form a group, isomorphic to the symmetric group S ₂ ^w . Therefore, we investigate the group S _n as well as one of its subgroups isomorphic to S _n/2 × S _n/2. We then consider the left cosets, the right cosets, and the double cosets generated by the subgroup. Each element of a coset can function as the representative of the coset. The coset can then be considered as the set of all group elements that differ from the representative by merely multiplying (either to the left or to the right or to both sides) by an arbitrary element of the subgroup. Different choices of the coset space and different choices of the coset representatives lead to six different syntheses for implementing an arbitrary reversible logic operation into hardware. Evaluation of all six methods, by means of three different cost functions (gate cost, switch cost, and quantum cost), leads to a best choice.     

Impact of Preferential P-Diffusion Along the Grain Boundaries on Fine-Grained Polysilicon Solar Cells

Thin-film polysilicon solar cells are a promising low-cost alternative for bulk silicon solar cells due to their reduced material thickness. Recently, we showed that the use of an amorphous silicon/polycrystalline silicon heterojunction emitter instead of a diffused homojunction emitter led to a boost in the open-circuit voltage by 90 mV. Now, we present a full evidence that shows that this improvement is related to the absence of dopant smearing along the grain boundaries. By using scanning spreading resistance microscopy, we found an enlargement of the junction area by a factor of five in case of a homojunction. The tips of the dopant spikes represent lowly doped areas with an enhanced recombination.     

ON-LINE MEASUREMENT OF THE MICROBIAL IMPACTS ON THE GERMINATION OF BARLEY DURING MALTING

During germination, the metabolic activity of sterile barley was more pronounced than the activity of barley contaminated by its endogenous microbial population. CO₂ and heat production profiles showed higher peak values when microbial activity was eliminated. Moreover, the maxima in the profiles appeared sooner than with barley in the presence of its natural microflora. More intensive growth of the acrospire was observed with sterile barley and a malt was obtained with a higher and more homogeneous modification. Reverse effects were noticed when sterile barley was inoculated with an Erwinia sp. strain and germination was evaluated. The results provide clear evidence for the strong interaction between microbial and plant metabolism, even for non dormant and non water sensitive barley. The ratio of CO₂ production to heat production levels was a useful tool for on-line monitoring of microbial activity during germination. In this way, the effects of the microbial activity can be taken into account in the development of a more effective control of the malting process. All experiments were performed using a specially designed solid-state reactor.     

Visual, cognitive, and neurodevelopmental outcome at 51/2 years in children with perinatal haemorrhagic-ischaemic brain lesions

To determine predictive values of early visual and neurocognitive assessment in children with perinatally acquired haemorrhagic or ischaemic brain lesions selected on the basis of ultrasound, 63 children (37 boys, 26 girls), who had been followed and examined until the age of 18 months, were reexamined at 5 1/2 years. Good correlations between visual and neurodevelopmental assessments at 18 months and at 5 1/2 years were found. When ultrasound abnormalities were combined with early visual and neurocognitive assessment data, good predictive values, especially for the group of children who had grade 2 to 4 leukomalacia, were found for visual acuity and neurodevelopment.