Hausdorff dimension of non-hyperbolic repellers. I: Maps with holes

This is the first paper in a two-part series devoted to studying the Hausdorff dimension of invariant sets of non-uniformly hyperbolic, non-conformal maps. Here we consider a general abstract model, that we call piecewise smooth maps with holes. We show that the Hausdorff dimension of the repeller is strictly less than the dimension of the ambient manifold. Our approach also provides information on escape rates and dynamical dimension of the repeller.

Temperature dependence of fractal dimension of grain boundary region in SnO2 based ceramics

Fractal dimensions of grain boundary region in doped SnO2 ceramics were determined based on previously derived fractal model. This model considers fractal dimension as a measure of homogeneity of distribution of charge carriers. Application of the derived fractal model enables calculation of fractal dimension using results of impedance spectroscopy. The model was verified by experimentally determined temperature dependence of the fractal dimension of SnO2 ceramics. Obtained results confirm that the non-Debye response of the grain boundary region is connected with distribution of defects and consequently with a homogeneity of a distribution of the charge carriers. Also, it was found that C-T-1 function has maximum at temperature at which the change in dominant type of defects takes place. This effect could be considered as a third-order transition.

Quantitative estimates of time-averaging in terebratulid brachiopod shell accumulations from a modern tropical shelf

Quantitative estimates of time-averaging in marine shell accumulations available to date are limited primarily to aragonitic mollusk shells. We assessed time-averaging in Holocene assemblages of calcitic brachiopod shells by direct dating of individual specimens of the terebratulid brachiopod Bouchardia rosea. The data were collected from exceptional (brachiopod-rich) shell assemblages, occurring surficially on a tropical mixed carbonate-siliciclastic shelf (the Southeast Brazilian Bight, SW Atlantic), a setting that provides a good climatic and environmental analog for many Paleozoic brachiopod shell beds of North America and Europe. A total of 82 individual brachiopod shells, collected from four shallow (5-25 m) nearshore (<2.5 km from the shore) localities, were dated by using amino acid racemization (D-alloisoleucine/L-isoleucine value) calibrated with five AMS-radiocarbon dates (r(2) = 0.933). This is the first study to demonstrate that amino acid racemization methods can provide accurate and precise ages for individual shells of calcitic brachiopods.The dated shells vary in age from modern to 3000 years, with a standard deviation of 690 years. The age distribution is strongly right-skewed: the young shells dominate the dated specimens and older shells are increasingly less common. However, the four localities display significant differences in the range of time-averaging and the form of the age distribution. The dated shells vary notably in the quality of preservation, but there is no significant correlation between taphonomic condition and age, either for individual shells or at assemblage level.These results demonstrate that fossil brachiopods may show considerable time-averaging, but the scale and nature of that mixing may vary greatly among sites. Moreover, taphonomic condition is not a reliable indicator of pre-burial history of individual brachiopod shells or the scale of temporal mixing within the entire assemblage. The results obtained for brachiopods are strikingly similar to results previously documented for mollusks and suggest that differences in mineralogy and shell microstructure are unlikely to be the primary factors controlling the nature and scale of time-averaging. Environmental factors and local fluctuations in populations of shell-producing organisms are more likely to be the principal determinants of time-averaging in marine benthic shelly assemblages. The long-term survival of brachiopod shells is incongruent with the rapid shell destruction observed in taphonomic experiments. The results support the taphonomic model that shells remain protected below (but perhaps near) the surface through their early taphonomic history. They may be brought back up to the surface intermittently by bioturbation and physical reworking, but only for short periods of time. This model explains the striking similarities in time-averaging among different types of organisms and the lack of correlation between time-since-death and shell taphonomy.

Analysis of the ethical aspects of professional confidentiality in dental practice

From the point of view of deontological ethics, privacy is a moral right that patients are entitled to and it is bound to professional confidentiality. Otherwise, the information given by patients to health professionals would not be reliable and a trustable relationship could not be established. The aim of the present study was to assess, by means of questionnaires with open and closed questions, the awareness and attitudes of 100 dentists working in the city of Andradina, São Paulo State, Brazil, with respect to professional confidentiality in dental practice. Most dentists (91.43%) reported to have instructed their assistants on professional confidentiality. However, 44.29% of the interviewees showed to act contradictorily as reported talking about the clinical cases of their patients to their friends or spouses. The great majority of professionals (98.57%) believed that it is important to have classes on Ethics and Bioethics during graduation and, when asked about their knowledge of the penalties imposed for breach of professional confidentiality, only 48.57% of them declared to be aware of it. Only 28.57% of the interviewees affirmed to have exclusive access to the files; 67.14% reported that that files were also accessed by their secretary; 1.43% answered that their spouses also had access, and 2.86% did not answer. From the results of the present survey, it could be observed that, although dentists affirmed to be aware of professional confidentiality, their attitudes did not adhere to ethical and legal requirements. This stand of health professionals has contributed to violate professional ethics and the law itself, bringing problems both to the professional and to the patient.

The dimension of the pore space in sponges

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

PI Stabilization of a Class of Time Delay Systems

In this paper we use the Hermite-Biehler theorem to establish results for the design of proportional plus integral (PI) controllers for a class of time delay systems. We extend results of the polynomial case to quasipolynomials using the property of interlacing in high frequencies of the class of time delay systems considered. A signature for the quasipolynomials in this class is derived and used in the proposed approach which yields the complete set of the stabilizing PI controllers.

Productivity of beet and roquette cultivation as a function of time of establishing intercropping

With the aim of evaluating the effect of intercropping on the productivity of beet and roquette crops, a study was conducted in the Section of Vegetable and Aromatic-Medicinal Plants, FCAV-UNESP, Jaboticabal/SP. The treatments consisted of co-cultivations of roquette (Cultivada) and beets (Early Wonder) established at 0, 7, 14 and 21 days after the transplanting of beets, and as monocultures of beets and roquette. The experiments were delineated in a randomized block design. The productivity of beets in monoculture was not superior to that obtained with intercropping with roquette. The production of dry mass of roquette with intercropping was less than that with monoculture and the reduction was more marked with more delayed establishment of co-cultivation. Intercropping established at 0 and 7 days after the transplanting of beets was the most efficient, with indices of efficient use of land of 1.26 and 1.27, respectively.

Productivity of lettuce and radish cultivations as a function of spacing and of time of establishment of intercropping

The experiment was conducted at UNESP, Jaboticabal-SP, during the period of September to November of 2000, with the objective of evaluating the productivity of the cultivation of lettuce and radishes as a function of spacing between plants and of the time of establishment of intercropping. The experimental design was a completely randomized blocks and four replications. The 14 treatments consisted of combinations of spacing between lines (0.30 and 0.40 m), cultivation systems (intercropping and monoculture), and time of sowing of radish seeds to establish intercropping (0, 7 and 14 days after transplant of lettuce). The cultivars of lettuce and radish were, 'Tainá' and 'Crimson Gigante', respectively. A greater yield of commercial radish roots was obtained with intercropping cultivation. The fresh mass of lettuce in monoculture did not differ from that produced with intercropping. These results suggest that intercropping cultivation between these species is advantageous.

PID stabilization of a class of time delay systems

In this paper we use the Hermite-Biehler theorem to establish results for the design of proportional plus integral plus derivative (PID) controllers concerning a class of time delay systems. Using the property of interlacing at high frequencies of the class of systems considered and linear programming we obtain the set of all stabilizing PID controllers. © 2005 IEEE.

Double optical monitoring of time-dependent film formation

A brief overview of optical monitoring for vacuum and wet bench film deposition processes is presented. Interferometric and polarimetric measurements are combined with regard to simultaneous real-time monitoring of refractive index and physical thickness. Monitor stability and accuracy are verified with transparent oil standards. This double optical technique is applied to dip coating with a multi-component Zirconyl Chloride aqueous solution, whose time varying refractive index and physical thickness curves indicate significant sensitivity to changes of film flow properties during the process.

Effect of time in hardness test on artificially demineralized human dental enamel

A cross-sectional microhardness (CSMH) test was carried out in human dental enamel exposed to a demineralizing solution in order to evaluate two different times of indentation in sound tissue and artificially induced caries. Twenty caries-free extracted human molars had one of their smooth surfaces sectioned and the enamel surface was isolated with nail polish except for an area of 6 mm2. These specimens were submitted to artificially induced enamel caries on a lactate buffer containing 0.1 ppm fluoride (F) during 28 days. All specimens were bisected to create groups A and B in which CSMH test was performed employing a Knoop indenter with a 25g load for 5 or 10 s, respectively. Student's paired t-test (p<0.05) was used to determine statistically significant differences between group A and B in 7 depths. There were no significant differences between any of the analyzed depths. Since the present experiment showed no significant difference when comparing indentations made with a 25 g load during either 5 or 10 s in different depths, this method can be used with either one of the time intervals tested without compromising a CSMH test on artificially demineralized human enamel.

Ethical Care of the Self and the Teacher in the Pedagogical Relationship: Reflections Based on the Latest Foucault

Our conception of education is that it is the responsible action whereby man becomes human, trains and faces the challenges that life and the world present, as man enters a larger, shared cultural tradition and thus joins the world. However such sharing implies that we must not just rely on tradition, but remain open to new ideas. It is essential for schooling to preserve a field where the art of living intersects with the world for which future generations are being prepared. It is in this field of intersection that this essay seeks to discuss Michel Foucault's thought, care of the self and the role played by others in the acquisition of ethical attitudes pertaining to one's conduct in life. Through reconstructing Foucault's ideas, we elaborate on the hypothesis that, before morally shaping students, teaching them values, or aiding in their skill acquisition in the sense prevailing in schooling today, it is important to understand the notion of care of the self (and how the notion implies interaction with others for effective care of the self). Care of the self is vital for thoroughly understanding the relationships between ethics and education in school. We particularly examine how Foucault's ideas and his analysis of the teacher's role in shaping the student's life conduct can help educators rethink pedagogical action in an ethical sense and find within it a certain openness to the formation of attitudes in educators and students

Effect of time between adhesive application and photoactivation on adhesion and collagen exposure

Fundacao de Amparo a Pesquisa do Estado de sao Paulo (FAPESP)