Small Furstenberg sets

For $\alpha$ in $(0,1]$, a subset $E$ of \RR is called Furstenberg set of type $\alpha$ or $F_\alpha$-set if for each direction $e$ in the unit circle there is a line segment $\ell_e$ in the direction of $e$ such that the Hausdorff dimension of the set $E\cap\ell_e$ is greater or equal than $\alpha$. In this paper we show that if $\alpha > 0$, there exists a set $E\in F_\alpha$ such that \HH{g}(E)=0 for $g(x)=x^{1/2+3/2\alpha}\log^{-\theta}(\frac{1}{x})$, $\theta>\frac{1+3\alpha}{2}$, which improves on the the previously known bound, that $H^{\beta}(E) = 0$ for $\beta>1/2+3/2\alpha$. Further, by refining the argument in a subtle way, we are able to obtain a sharp dimension estimate for a whole class of zero-dimensional Furstenberg type sets. Namely, for \h_\gamma(x)=\log^{-\gamma}(\frac{1}{x}), $\gamma>0$, we construct a set E_\gamma\in F_{\h_\gamma} of Hausdorff dimension not greater than 1/2. Since in a previous work we showed that 1/2 is a lower bound for the Hausdorff dimension of any E\in F_{\h_\gamma}, with the present construction, the value 1/2 is sharp for the whole class of Furstenberg sets associated to the zero dimensional functions \h_\gamma.Comment: Final versio

Células gliales ¿Servidoras de las neuronas o compañeras de equipo?

Las neuronas no son las únicas células del sistema nervioso y quizá tampoco las únicas responsablesde las funciones importantes.Fil: Rela, Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Fisiología y Biofísica Bernardo Houssay. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología y Biofísica Bernardo Houssay; Argentin

PENINGKATAN KEMAMPUAN MENYELESAIKAN SOAL CERITA PECAHAN MELALUI MODEL KOOPERATIF THE POWER OF TWO PADA SISWA KELAS IV SDN KENEP 01 TAHUN AJARAN 201/2012

ABSTRAK rela Andriyana.PENINGKATAN KEMAMPUAN MENYELESAIKAN SOAL CERITA PECAHAN MELALUI MODEL KOOPERTIF THE POWER OF TWO PADA SISWA KELAS IV SEKOLAH DASAR NEGERI KENEP 01 KECAMATAN SUKOHARJO KABUPATEN SUKOHARJO TAHUN AJARAN 2011/2012. Skripsi, Fakultas Keguruan dan Ilmu Pendidikan Universitas Sebelas Maret Surakarta. Oktober 2012. Tujuan penelitian ini adalah meningkatkan kemampuan menyelesaikan soal cerita pecahan melalui pembelajaran kooperatif The Power Of Two. Penelitian dilaksanakan dalam dua siklus. Setiap siklus terdiri dari perencanaan, pelaksanaan tindakan, observasi, dan refleksi. Subjek penelitiannya adalah siswa kelas IV SD Negeri Kenep 01 Tahun ajaran 2011/2012 yang berjumlah 18 siswa terdiri dari 8 siswa laki-laki dan 10 siswa perempuan. Data yang diperoleh peneliti yaitu sumber data pokok (Primer) yaitu dari para siswa, guru, kepala sekolah SD Negeri Kenep 01. Sumber data sekunder meliputi arsip/dokumen, dan hasil observasi oleh guru kelas sendiri. Nilai rata-rata kelas yaitu sebelum tindakan sebesar 54,44; siklus I naik menjadi 64,16 dan pada siklus II naik menjadi 79,16. Simpulan penelitian ini adalah penerapan pembelajaran kooperatif The Power Of Two dapat meningkatkan kemampuan menyelesaikan soal cerita pada siswa kelas IV SDN Kenep 01 Sukoharjo Tahun 2011/2012 Kata kunci: soal cerita pecahan, model kooperatif The Power Of Two, kemampuan menyelesaikan ABSTRACT Rela Andriyana. THE IMPROVEMENT SOLVE ABILITY STORY PROBLEM FRACTION WITH USED COOPERTIVE MODEL THE POWER OF TWO OF THE STUDENTS IN THE FOURTH GRADE STUDENTS ELEMENTARY SCHOOL KENEP 01 , SUKOHARJO SUBDISTRICT, SUKOHARJO REGENCY ACADEMIC YEAR 2011/2012. Skripsi: The Faculty of Teacher Training and Education, Sebelas Maret University, Surakarta October 2012. The aim of this research is to improve solve ability story problem fraction with used cooperative model The Power Of Two. This research belongs to a classroom action research. The research was carried out in two cycles. Each cycle consists of planning, action, observation, and reflection. Subjects were elementary school students in fourth grade Kenep 01 Academic Year 2011/2012 which amounts to 18 students consist of 8 boys and 10 girls. The source data were obtained from primary data of students, teachers, and Headmaster of Elementary school Kenep 01. The source of secondary data consist of file/document and the result observation by teacher foutth class. The average value of the cycle pre-class 54,44; the first cycle raise to 64,16 and at 79,16 reached second cycle. The conclusions of this research is implementation sociodramatic methods could develop the motivation to learn mathematics in the fourth grade students Elementary School Kenep 01 Sukoharjo year 2011/2012 Key Word : soal cerita pecahan, model kooperatif The Power Of Two, kemampuan menyelesaika

Ética de María Zambrano: dupla fidelidade ao absoluto e ao momento em que se vive

A pensadora espanhola baseia sua ética em três pontos: no conceito de pessoa, na liberdade de ação e na consciência histórica. O que se pretende é apresentar como esses «ingredientes» se misturam para que ocorra o agir ético. O caminho a ser percorrido será a apresentação do que a filósofa entende como tempo e suas dimensões, sua ação no eu absoluto e na formação da consciência histórica, tendo como resultado final a transformação do homem como protagonista da história ética.The Maria Zambrano’s ethic is based on three points: the concept of person, the freedom of the action and on the historical consciousness. The aim of this text is to present how these three points are mixed to make possible the ethic action. Therefore, is necessary to understand how the philosopher explains the time dimensions and its action on the absolute in order to transform the human person as a protagonist on an ethical history

The Spacing Effect for Structural Synaptic Plasticity Provides Specificity and Precision in Plastic Changes

In contrast to trials of training without intervals (massed training), training trials spaced over time (spaced training) induce a more persistent memory identified as long-term memory (LTM). This phenomenon, known as the spacing effect for memory, is poorly understood. LTM is supported by structural synaptic plasticity; however, how synapses integrate spaced stimuli remains elusive. Here, we analyzed events of structural synaptic plasticity at the single-synapse level after distinct patterns of stimulation in motoneurons of Drosophila. We found that the spacing effect is a phenomenon detected at synaptic level, which determines the specificity and the precision in structural synaptic plasticity. Whereas a single pulse of stimulation (massed) induced structural synaptic plasticity, the same amount of stimulation divided in three spaced stimuli completely prevented it. This inhibitory effect was determined by the length of the interstimulus intervals. The inhibitory effect of the spacing was lost by suppressing the activity of Ras or mitogen-activated protein kinase, whereas the overexpression of Ras-WT enhanced it. Moreover, dividing the same total time of stimulation into five or more stimuli produced a higher precision in the number of events of plasticity. Ras mutations associated with intellectual disability abolished the spacing effect and led neurons to decode distinct stimulation patterns as massed stimulation. This evidence suggests that the spacing effect for memory may result from the effect of the spacing in synaptic plasticity, which appears to be a property not limited to neurons involved in learning and memory. We propose a model of spacing-dependent structural synaptic plasticity.Fil: San Martín, Alvaro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Fisiología y Biofísica Bernardo Houssay. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología y Biofísica Bernardo Houssay; ArgentinaFil: Rela, Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Fisiología y Biofísica Bernardo Houssay. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología y Biofísica Bernardo Houssay; ArgentinaFil: Gelb, Bruce. Icahn School of Medicine at Mount Sinai; Estados UnidosFil: Pagani, Mario Rafael. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Fisiología y Biofísica Bernardo Houssay. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología y Biofísica Bernardo Houssay; Argentin