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31.
Cutaneous larva migrans is the result of infestation of human skin by helminth larvae, which burrow through the epidermis. This route of infestation makes the foot a typical site for origination of this infection. Children, who frequently play barefoot in locations where the most common of the helminth larvae, the dog and cat hookworms, are endemic, are at particular risk for this disorder. This article reviews the differential diagnosis of cutaneous larva migrans and current concepts in management. Two cases of related children who presented to their pediatricians with this condition are reported. 相似文献
32.
The authors present a review of the classification, aetiology, presentation, treatment and long-term outcome of children and adults with biliary atresia and choledochal cyst disease. Biliary atresia should be suspected in any infant with jaundice beyond the second week of life. Although the aetiology and pathogenesis remain unclear, early management with portoenterostomy has significantly improved the course of this disease. Recent advances in immunosuppression have made liver transplantation a valuable and necessary adjunct to biliary bypass. With choledochal cyst disease, adults, unlike children, often present with acute biliary tract symptoms or pancreatitis. The treatment of choice remains extrahepatic cyst excision and biliary bypass. This treatment has excellent long-term results that minimize the development of malignancy. 相似文献
33.
Line narrowing and self frequency scanning of a laser diode array coupled to a photorefractive passive-phase conjugate mirror has been demonstrated. Single-longitudinal mode operation is obtained and the coupling mechanism is discussed 相似文献
34.
We prove that there is no black-box construction of a one-way permutation family from a one-way function and an indistinguishability obfuscator for the class of all oracle-aided circuits, where the construction is “domain invariant” (i.e., where each permutation may have its own domain, but these domains are independent of the underlying building blocks). Following the framework of Asharov and Segev (FOCS ’15), by considering indistinguishability obfuscation for oracle-aided circuits we capture the common techniques that have been used so far in constructions based on indistinguishability obfuscation. These include, in particular, non-black-box techniques such as the punctured programming approach of Sahai and Waters (STOC ’14) and its variants, as well as sub-exponential security assumptions. For example, we fully capture the construction of a trapdoor permutation family from a one-way function and an indistinguishability obfuscator due to Bitansky, Paneth, and Wichs (TCC ’16). Their construction is not domain invariant, and our result shows that this, somewhat undesirable property, is unavoidable using the common techniques. In fact, we observe that constructions which are not domain invariant circumvent all known negative results for constructing one-way permutations based on one-way functions, starting with Rudich’s seminal work (PhD thesis ’88). We revisit this classic and fundamental problem and resolve this somewhat surprising gap by ruling out all such black-box constructions—even those that are not domain invariant. 相似文献
35.
Families and Networks of Internet Memes: The Relationship Between Cohesiveness,Uniqueness, and Quiddity Concreteness
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Elad Segev Asaf Nissenbaum Nathan Stolero Limor Shifman 《Journal of Computer-Mediated Communication》2015,20(4):417-433
This study employs a large‐scale quantitative analysis to reveal structural patterns of internet memes, focusing on 2 forces that bind them together: the quiddities of each meme family and the generic attributes of the broader memetic sphere. Using content and network analysis of 1013 meme instances (including videos, images, and text), we explore memes' prevalent quiddity types and generic features, and the ways in which they relate to each other. Our findings show that (a) higher cohesiveness of meme families is associated with a greater uniqueness of their generic attributes; and (b) the concreteness of meme quiddities is associated with cohesiveness and uniqueness. We discuss the implications of these findings to the understanding of internet memes and participatory culture. 相似文献
36.
Visual looming is related to an increasing projected size of an object on a viewer's retina as the relative distance between the viewer and the object decreases. It is an indication for threat that may be used along with visual fixation to accomplish navigation tasks. This paper defines visual looming as the time derivative of the relative distance (range) between the observer and the object divided by the relative distance itself. It introduces a unified approach to visual looming by showing how visual looming can be calculated from the relative temporal change in the following attributes of a 2D image sequence: (i) image area, (ii) image brightness, (iii) texture density in the image, and (iv) image blur. It is shown that a closed-form unified expression can be adopted in all these methods. Experimental results illustrate how the measured values of looming are related to the actual values. Finally, looming is used in the sense of a threat of collision, along with visual fixation, to navigate in an unknown environment. 相似文献
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38.
Tze‐Bin Song Zhenghao Yuan Megumi Mori Faizan Motiwala Gideon Segev Eloïse Masquelier Camelia V. Stan Jonathan L. Slack Nobumichi Tamura Carolin M. Sutter‐Fella 《Advanced functional materials》2020,30(6)
The exploration of the synthetic space of halide perovskites hinges on an enormous number of parameters requiring time‐consuming experimentation to decouple and optimize. Here, the formation of the prototype material CH3NH3PbI3 (MAPbI3) is investigated at different time and length scales using multimodal in situ measurements to monitor the evolution of crystalline phases, morphology, and photoluminescence as a function of the lead precursors. Kinetically fast formation of crystalline precursor phases already during the spin‐coat deposition is observed using lead iodide (PbI2) or lead chloride (PbCl2) routes. These precursor phases most likely template final MAPbI3 film morphology. In particular, the emergence of the “needle‐like” structure is shown to appear before film annealing. In situ photoluminescence measurements suggest nanoscale nucleation followed by rapid nuclei densification and growth. Using this multimodal in situ approach, different formation pathways can be identified either via precursor phases in the PbI2 and PbCl2 routes or direct perovskite formation from molecular building blocks as observed in the lead acetate (PbAc2) route. Correlation of in situ results with photovoltaic device performance demonstrates the power of in situ multimodal techniques, paves the way to a fast screening of synthetic parameters, and ultimately leads to controlled synthetic procedures that yield high‐efficiency devices. 相似文献
39.
Liu Yichuan James Hailey Gupta Otkrist Raviv Dan 《International Journal on Document Analysis and Recognition》2022,25(1):29-39
International Journal on Document Analysis and Recognition (IJDAR) - Detecting and extracting information from the machine-readable zone (MRZ) on passports and visas is becoming increasingly... 相似文献
40.
The authors examined the hypothesis that the interaction between the need for cognitive structure (NCS) and the ability to achieve cognitive structure (AACS) moderates the effect of stress on information processing. NCS is the preference for using cognitive structuring, as opposed to piecemeal processes, as a means to achieve certainty. AACS is the extent to which individuals are able to apply information processes that are consistent with their levels of NCS. The hypothesis was validated in 4 studies, which showed that stress increased high-AACS participants' use of cognitive structuring if they had high NCS and reduced it if they had low NCS. An opposite effect was found for low-AACS participants. The implications of these results for the understanding of the mechanisms responsible for the effect of stress on information processing are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献