Given a passage with a context and an answer, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.

Context: Behavioral studies of spatial navigation in aging indicate that orientation using an allocentric reference frame (object-centered orientation) is impaired, whereas orientation using egocentric processes (self-centered orientation) is not. It has been proposed that navigational deficits may result from more general alterations of perception and attention or executive functions. The purpose of this study is to assess allocentric and egocentric representation in elderly individuals, and to determine if age-related deficits in spatial navigation are related to an attentional decline.', 'We assessed encoding of the position of geometrical shapes, depending specifically on an allocentric or egocentric reference frame, during ERP recording in young and old subjects.', 'Aging was associated with a performance decline in allocentric, but not egocentric, encoding. Both allocentric and egocentric conditions elicited parietal early components P1 and N1, reflecting top-down modulation, and components P2 and N2, reflecting selective attention and stimulus categorization. We observed age-associated effects on N1 and N2 amplitudes and on N2 latency in both spatial conditions. Moreover, impaired allocentric performance in older subjects was associated with a greater P2 amplitude and delayed P2 latency compared with younger subjects.
Answer: These results suggest that elderly individuals present with deficits when spatial orientation relies on allocentric representation, and are associated with age-related deficits in spatial attention.
Is allocentric but not egocentric orientation impaired during normal aging : an ERP study?

Context: To establish a novel approach for quick and high throughput verification of human gene imprinting.', "By use of a pair of dye-labeled probes, 5' nuclease assay was combined with reverse transcriptase-PCR(RT-PCR) to genotype a coding single nucleotide polymorphism (cSNP), rs705(C/T) of a known imprinted gene, small nuclear ribonucleotide protein N (SNRPN), on both genomic DNA and cDNA of human lymphoblast cell lines.", 'Allele discrimination showed a clear monoallelic expression pattern of SNRPN, which was confirmed by RT-PCR based restriction fragment length polymorphisms. Pedigree analysis verified the paternal origin of expressed allele, which is in consistency with previous report.
Answer: Coding SNP is an ideal marker for detecting gene imprinting by 5' nuclease assay. This approach has also a potentiality to discover differential allele expression of non-imprinted genes in order to find gene cis-acting functional polymorphism.
Is [ Coding single nucleotide polymorphism an ideal marker for detecting gene imprinting by 5 ' nuclease assay ]?

Context: To investigate the potential efficacy of real-time contrast-enhanced power Doppler sonography in the differentiation of benign and malignant adnexal masses in a pilot study.', 'Before surgical treatment, adnexal masses were prospectively evaluated with power Doppler sonography before and after injection of a contrast agent. Real-time postinjection sequences were computerized with time-intensity analysis software to determine an enhancement curve and contrast parameters. The intraobserver and interobserver reproducibilities of these criteria were assessed on a subsample. These contrast parameters were compared between benign and malignant tumors using logistic regression. Sensitivity and specificity were used to compare contrast parameters with sonographic and Doppler variables.', 'Ninety-nine women were included, for a total of 101 adnexal masses. There were 23 cases of ovarian malignancies and 78 benign adnexal lesions. Our procedure had excellent intraobserver and interobserver reproducibility, with an average intraclass correlation coefficient of 0.92. The time before enhancement and intensity ratio did not reliably differentiate between the benign and malignant masses. Washout times and areas under the curves were significantly greater in ovarian malignancies than in other benign tumors (P < .001), leading to sensitivity estimates between 96% and 100% and specificity estimates between 83 and 98%. Contrast parameters had slightly higher sensitivity and slightly lower specificity when compared with transvaginal sonographic variables of the resistive index and serum cancer antigen 125 levels.
Answer: Contrast-enhanced power Doppler imaging may easily and precisely discriminate benign from malignant adnexal lesions. Larger studies are needed to determine the appropriate use and benefits of this new procedure.

Does contrast-enhanced sonography help in discrimination of benign from malignant adnexal masses?