Relational color constancy in achromatic and isoluminant images

Relational color constancy, which refers to the constancy of perceived relations between surface colors under changes in illuminant, may be based on the computation of spatial ratios of cone excitations. As this activity need occur only within rather than between cone pathways, relational color constancy might be assumed to be based on relative luminance processing. This hypothesis was tested in a psychophysical experiment in which observers viewed simulated images of Mondrian patterns undergoing colorimetric changes that could be attributed either to an illuminant change or to a nonilluminant change; the images were isoluminant, achromatic, or unmodified. Observers reliably discriminated the two types of changes in all three conditions, implying that relational color constancy is not based on luminance cues alone. A computer simulation showed that in these isoluminant and achromatic images spatial ratios of cone excitations and of combinations of cone excitations were almost invariant under illuminant changes and that discrimination performance could be predicted from deviations in these ratios.Biotechnology and Biological Sciences Research Council (BBSRC

The karyotype of three Brazilian Terrarana frogs (Amphibia, Anura) with evidence of a new Barycholos species

A recent substantial rearrangement of the 882 described eleutherodactyline frog species has considerably improved the understanding of their systematics. Nevertheless, many taxonomic aspects of the South American eleutherodactyline species remain unknown and require further investigation using morphological, cytogenetic and molecular approaches. In this work, the karyotypes of the Brazilian species Ischnocnema juipoca (Atibaia and Campos do Jordão, SP), Barycholos cf. ternetzi (Uberlândia, MG, and Porto Nacional, TO), and Pristimantis crepitans (Chapada dos Guimarães and São Vicente, MT) were analyzed using Giemsa staining, Ag-NOR labeling, and C-banding techniques. All individuals had a diploid number of 22 chromosomes, but the Fundamental Numbers were different among species. The herein described low chromosome number of Pristimantis crepitans is unique within this genus, suggesting that cytogenetically this species is not closely related either to its congeneric species or to Ischnocnema. In addition, karyotype differences, mainly in the NOR position, clearly distinguished the two Barycholos populations, besides indicating the existence of a so far undescribed species in this genus. A taxonomic review could clarify the systematic position of P. crepitans and verify the hypothetic new Barycholos species

Enterorrhagia due to pelvic hematoma after femoral catheterization

Arterial puncture, better known as catheterization, has become an important diagnostic tool in recent years. For its realization, generally the option is the Seldinger technique, which is considered today the safest and most often used procedure. This technique allows the insertion of large-caliber or multiple-lumen catheters in the vessel. Arterial catheterization helps in several exams, for instance, mesenteric angiography and cardiac output assessment, and contributes in cineangiocoronariography procedures. We report the case of a 67-year-old male patient who was submitted to cineangiocoronariography and evolved with enterorrhagia due to pelvic hematoma. Throughout the patient's care, a conservative treatment was chosen. The progression of the patient was uneventful and then the patient was discharged. It is very hard to determine which arterial segment was injured; however, as the hematoma was located predominantly in the pelvic region, it is believed that an injury occurred at the internal iliac artery, or directly at the bifurcation of the common iliac artery. Furthermore, it is assumed that a catheter kinking occurred during its progression, due to any tortuosity or to the presence of an atheromatous plaque, thus favoring the occurrence of the more distal lesion, rather than the proximal one. We decided to report this case because of its high degree of rarity, with a scarce number of papers in the literature related to the topic. Thus, with the description of this report we believe that other medical teams will have facilitated their decision-making process, when facing a similar case

A psychometric study of an executive function assessment instrument (TDI-FE)

Abstract Background This study aims to present and discuss the psychometric properties of executive functions, which were measured using the TDI-FE instrument. The analysis encompasses its internal structure, potential sensitivity to fatigue factors, relationships with external criteria, and diagnostic accuracy. Methods The study sample comprised 382 students from Brazil, aged 6–8 years. Child development variables were screened using the TDI-FE and gold standard tests (Cancellation Attention and Trail Making Tests). The proposed scale comprised four activities: a test with fruit images with three tasks, and one memory game. Results The one-factor model of EF of the TDI-FE failed to fit to the data. However, fit substantially improved once a latent fatigue factor was controlled in the model. The latent factor of EF assessed by the TDI-FE tasks was coherently associated with a series of external variables, including two popular collateral measures of EF. The diagnostic accuracy was reasonable, and a cut-off of 37 points produced 70% of sensitivity and 60% of specificity. Conclusion Results indicated that the TDI-FE demonstrated sound psychometric properties and diagnostic accuracy, then consisting of an efficient alternative for the assessment of EFs in early childhood education. The study also proved the need to control for response biases such as fatigue in the latent variable models of EF. The TDI-FE is notable because of its low cost and easy application, and it might fulfill a need for instruments for individuals from different contexts at this stage of development in Brazil