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1.
F Mota JH Kanan N Rayment T Mould A Singer BM Chain 《Canadian Metallurgical Quarterly》1997,150(4):1223-1229
We have investigated the expression of the aspartic proteinase cathepsin E and HLA-DR and the presence of HPV16 in normal squamous epithelium (n = 8) and low-grade (n = 21) and high-grade (n = 14) intraepithelial squamous lesions of the uterine cervix. Immunohistochemistry of cervical biopsies revealed that up-regulation of cathepsin E expression was related to increasing severity of the cervical intraepithelial neoplasia (CIN). Up-regulation of protein was associated with increased message as assessed by in situ hybridization. Langerhans cells and the majority of koilocytes did not express detectable cathepsin E levels. Although there was also an up-regulation of HLA-DR expression by cervical keratinocytes in cervical intraepithelial neoplasia lesions, as determined by immunohistochemistry, no significant correlation was found between HLA-DR and cathepsin E expression in these lesions; neither was expression of cathepsin E correlated to the presence of HPV16, detected by polymerase chain reaction. The expression of cathepsin E, an aspartic proteinase that is reported to play a role in antigen processing for presentation by class II major histocompatibility complex molecules, is associated with cellular dedifferentiation in cervical intraepithelial neoplasia. 相似文献
2.
Singer A.C. Kozat S.S. Feder M. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》2002,48(8):2354-2362
We consider the problem of sequential linear prediction of real-valued sequences under the square-error loss function. For this problem, a prediction algorithm has been demonstrated whose accumulated squared prediction error, for every bounded sequence, is asymptotically as small as the best fixed linear predictor for that sequence, taken from the class of all linear predictors of a given order p. The redundancy, or excess prediction error above that of the best predictor for that sequence, is upper-bounded by A/sup 2/P ln(n)/n, where n is the data length and the sequence is assumed to be bounded by some A. We provide an alternative proof of this result by connecting it with universal probability assignment. We then show that this predictor is optimal in a min-max sense, by deriving a corresponding lower bound, such that no sequential predictor can ever do better than a redundancy of A/sup 2/p ln(n)/n. 相似文献
3.
Constructing inferences during narrative text comprehension. 总被引:1,自引:0,他引:1
Describes a constructionist theory that accounts for the knowledge-based inferences that are constructed when readers comprehend narrative text. Readers potentially generate a rich variety of inferences when they construct a referential situation model of what the text is about. The proposed constructionist theory specifies that some, but not all, of this information is constructed under most conditions of comprehension. The distinctive assumptions of the constructionist theory embrace a principle of search (or effort) after meaning. According to this principle, readers attempt to construct a meaning representation that addresses the reader's goals, that is coherent at both local and global levels, and that explains why actions, events, and states are mentioned in the text. This study reviews empirical evidence that addresses this theory and contrasts it with alternative theoretical frameworks. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
4.
Illustrates how discrete-time survival analysis can address questions about onset, cessation, relapse, and recovery. Using data on the onset of suicide ideation and depression and relapse into cocaine use, the authors introduce key concepts underpinning the method, describe the action of the discrete-time hazard model, and discuss several types of main effects and interactions that can be included as predictors. Practical issues of data analysis and strategies for interpretation and presentation are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
5.
Applications of loss-free elements with resistive characteristics in power processing systems are discussed. The synthesis of this kind of element is based on the control of a two port which has a transformer or gyrator matrix. Both of the controlled two ports can be realized by means of switched mode circuits. The loss-free resistor can be applied to the stabilization of unstable systems, for damping oscillatory waveforms, and balancing of power flow in AC-DC conversion systems. This kind of element has been applied to the stabilization of a gas laser system. It replaced a conventional resistive element which was applied for this purpose 相似文献
6.
Seok-Jun Lee Shanbhag N.R. Singer A.C. 《Very Large Scale Integration (VLSI) Systems, IEEE Transactions on》2005,13(8):921-933
Iterative decoders such as turbo decoders have become integral components of modern broadband communication systems because of their ability to provide substantial coding gains. A key computational kernel in iterative decoders is the maximum a posteriori probability (MAP) decoder. The MAP decoder is recursive and complex, which makes high-speed implementations extremely difficult to realize. In this paper, we present block-interleaved pipelining (BIP) as a new high-throughput technique for MAP decoders. An area-efficient symbol-based BIP MAP decoder architecture is proposed by combining BIP with the well-known look-ahead computation. These architectures are compared with conventional parallel architectures in terms of speed-up, memory and logic complexity, and area. Compared to the parallel architecture, the BIP architecture provides the same speed-up with a reduction in logic complexity by a factor of M, where M is the level of parallelism. The symbol-based architecture provides a speed-up in the range from 1 to 2 with a logic complexity that grows exponentially with M and a state metric storage requirement that is reduced by a factor of M as compared to a parallel architecture. The symbol-based BIP architecture provides speed-up in the range M to 2M with an exponentially higher logic complexity and a reduced memory complexity compared to a parallel architecture. These high-throughput architectures are synthesized in a 2.5-V 0.25-/spl mu/m CMOS standard cell library and post-layout simulations are conducted. For turbo decoder applications, we find that the BIP architecture provides a throughput gain of 1.96 at the cost of 63% area overhead. For turbo equalizer applications, the symbol-based BIP architecture enables us to achieve a throughput gain of 1.79 with an area savings of 25%. 相似文献
7.
Children can express thoughts in gesture that they do not express in speech--they produce gesture-speech mismatches. Moreover, children who produce mismatches on a given task are particularly ready to learn that task. Gesture, then, is a tool that researchers can use to predict who will profit from instruction. But is gesture also useful to adults who must decide how to instruct a particular child? We asked 8 adults to instruct 38 third- and fourth-grade children individually in a math problem. We found that the adults offered more variable instruction to children who produced mismatches than to children who produced no mismatches--more different types of instructional strategies and more instructions that contained two different strategies, one in speech and the other in gesture. The children thus appeared to be shaping their own learning environments just by moving their hands. Gesture not only reflects a child's understanding but can play a role in eliciting input that could shape that understanding. As such, it may be part of the mechanism of cognitive change. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
8.
Demands by Patients or their Families for treatment thought to be inappropriate by health care providers constitute an important set of moral problems in clinical practice. A variety of approaches to such cases have been described in the literature, including medical futility, standard of care and negotiation. Medical futility fails because it confounds morally distinct cases: demand for an ineffective treatment and demand for an effective treatment that supports a controversial end (e.g., permanent unconsciousness). Medical futility is not necessary in the first case and is harmful in the second. Ineffective treatment falls outside the standard of care, and thus health care workers have no obligation to provide it. Demands for treatment that supports controversial ends are difficult cases best addressed through open communication, negotiation and the use of conflict-resolution techniques. Institutions should ensure that fair and unambiguous procedures for dealing with such cases are laid out in policy statements. 相似文献
9.
More than half of all U.S. infants and toddlers spend at least 20 hr per week in the care of a nonparent adult. This article uses survival analysis to identify which families are most likely to place their child in care and the ages when these choices are made, using data from a national probability sample of 2,614 households. Median age at first placement is 33 months, but age varies by geographic region, mother's employment status during pregnancy, mother's education level, and family structure (1 vs. 2 parents, mother's age at 1st birth, and number of siblings). Controlling for these effects, differences by race and ethnicity are small. Implications for studies of child-care selection and evaluations of early childhood programs are discussed. 相似文献