3,843 research outputs found
CMB Neutrino Mass Bounds and Reionization
Current cosmic microwave background (CMB) bounds on the sum of the neutrino
masses assume a sudden reionization scenario described by a single parameter
that determines the onset of reionization. We investigate the bounds on the
neutrino mass in a more general reionization scenario based on a principal
component approach. We found the constraint on the sum of the neutrino masses
from CMB data can be relaxed by a 40% in a generalized reionization
scenario. Moreover, the amplitude of the r.m.s. mass fluctuations is
also considerably lower providing a better consistency with a low amplitude of
the Sunyaev-Zel'dovich signal
Pengaruh Efikasi Diri Dan Kemandirian Belajar Terhadap Hasil Belajar Mata Kuliah Geometri Dasar Pada Mahasiswa Program Studi Pendidikan Matematika Universitas Flores
Kesuksesan mahasiswa belajar diperguruan tinggi sangat dipengaruhi oleh semangat hidup yang tinggi, dan rasa optimis yang besar terhadap kesuksesan. Kesuksesan akan diraih oleh mahasiswa jika mahasiswa tersebut mampu untuk mengatasi kesulitan-kesulitan yang mungkin terjadi pada saat perkuliahan. Salah satu kesulitan yang juga berperan penting bagi mahasiswa untuk meraih kesuksesan adalah efikasi diri dan kemandirian belajar. Setiap mahasiswa mempunyai kesulitan yang berbeda-beda, baik dalam hal mata kuliah maupun dalam hal penerimaan metode pembelajaran yang diberikan. Â Oleh karena itu penelitian ini bertujuan untuk melihat sejauh mana Pengaruh efikasi diri dan kemandirian belajar siswa terhadap hasil belajar mata kuliah geometri dasar program studi pendidikan matematika universitas Flores. Penelitian ini merupakan penelitian explanatory yang menjelaskan hubungan kausal antara variable-variabel yang mempengaruhi hipotesis atau teori yang menjelaskan mengapa suatu fenomena terjadi. Fenomena dalam penelitian ini adalah efikasi diri dan kemandirian belajar mahasiswa. Hasil penelitian ini menunjukkan Efikasi Diri (X1) dan Kemandirian Belajar (X2) mempunyai pengaruh yang positif terhadap Hasil Belajar (Y) diketahui dari hasil analisis korelasi diperoleh dari nilai R hitung untuk X1 terhadap Y sebesar 0.607 dan X2 terhadap Y nilai R hitung diperoleh sebesar 0.583 dan nilai signifikansi antara X1 dan X2 terhadap Y diperoleh dua tanda bintang (**) sehingga ada pengaruh positif dengan taraf signifikansi 1 %.. Dengan kata lain semakin meningkatnya atau semakin baiknya Efikasi Diri dan Kemandirian Belajar maka akan meningkat pula hasil belajar dari mahasiswa itu sendiri. Kata kunci : Efikasi Diri; Hasil Belajar; Geometri Dasa
High-resolution multiphoton tomography and fluorescence lifetime imaging of UVB-induced cellular damage on cultured fibroblasts producing fibres
Background: Multiphoton tomography (MPT) is suitable to perform both ex vivo and in vivo investigations of living skin and cell cultures with submicron resolution. Fluorescence lifetime imaging (FLIM) generates image contrast between different states of tissue characterized by various fluorescence decay rates. Our purpose was to combine MPT and FLIM to evaluate fibroblasts and collagen fibres produced in vitro. Methods: Fibroblast cultures, 2-4 days old, at a subconfluent stage, were evaluated before and after irradiation with a single UVB dose. One month old cultures stimulated with ascorbic acid were also assessed. Results: After UVB radiation, fibroblasts appear irregular in size, lose their alignment and show a decrease in fluorescence lifetime. One month-old fibroblasts, producing collagen fibres after stimulation with ascorbic acid, appear as small roundish structures intermingled by filaments showing a granular arrangement. Conclusion: The combination of MPT and FLIM may be useful for the in vitro study of cell modifications induced by injurious or protective agents and drugs. © 2013 John Wiley & Sons A/S
Harrison-Z'eldovich primordial spectrum is consistent with observations
Inflation predicts primordial scalar perturbations with a nearly
scale-invariant spectrum and a spectral index approximately unity (the
Harrison--Zel'dovich (HZ) spectrum). The first important step for inflationary
cosmology is to check the consistency of the HZ primordial spectrum with
current observations. Recent analyses have claimed that a HZ primordial
spectrum is excluded at more than 99% c.l.. Here we show that the HZ spectrum
is only marginally disfavored if one considers a more general reionization
scenario. Data from the Planck mission will settle the issue.Comment: 4 Pages, 2 Figure
Impact of general reionization scenarios on extraction of inflationary parameters
Determination of whether the Harrison--Zel'dovich spectrum for primordial
scalar perturbations is consistent with observations is sensitive to
assumptions about the reionization scenario. In light of this result, we
revisit constraints on inflationary models using more general reionization
scenarios. While the bounds on the tensor-to-scalar ratio are largely
unmodified, when different reionization schemes are addressed, hybrid models
are back into the inflationary game. In the general reionization picture, we
reconstruct both the shape and amplitude of the inflaton potential. We find a
broader spectrum of potential shapes when relaxing the simple reionization
restriction. An upper limit of GeV to the amplitude of the potential
is found, regardless of the assumptions on the reionization history.Comment: 10 Pages, 9 figure
Augmented Exercise Biking with Virtual Environments for Elderly Users:Considerations on the use of auditory feedback
Virtual reality (VR) has been shown to function well as an assistive technology to physical therapy for elderly users. Elderly users, and more specifically retirement home residents, form a unique user group in this field, due to their characteristics and demands. In a case study, retirement home residents used an audio-visual virtual environment (VE) augmentation for an exercise bike. Besides a visual display, a soundscape was played to the subjects using headphones. The soundscape was not no- ticed wand the headphones were found to be obtrusive. In this paper, we consider and discuss possible approaches to alternative auditory and haptic delivery methods for future studies. These nonvisual displays need to fit the requirements and limitations of the retirement home subjects who are to exercise using the VE-based augmenta- tion from the case study
Perturbative approach to the structure of rapidly rotating neutron stars
We construct models of rotating stars using the perturbative approach
introduced by J. Hartle in 1967, and a set of equations of state proposed to
model hadronic interactions in the inner core of neutron stars. We integrate
the equations of stellar structure to third order in the angular velocity and
show, comparing our results to those obtained with fully non linear codes, to
what extent third order corrections are needed to accurately reproduce the
moment of inertia of a star which rotates at rates comparable to that of the
fastest isolated pulsars.Comment: 17 pages, 5 figures, minor changes to match version accepted by Phys.
Rev.
RNA-seq analysis of salt-stressed versus non salt-stressed transcriptomes of chenopodium quinoa landrace R49
Quinoa (Chenopodium quinoa Willd.), a model halophytic crop species, was used to shed light on salt tolerance mechanisms at the transcriptomic level. An RNA-sequencing analysis of genotype R49 at an early vegetative stage was performed by Illumina paired-ends method comparing high salinity and control conditions in a time-course pot experiment. Genome-wide transcriptional salt-induced changes and expression profiling of relevant salt-responsive genes in plants treated or not with 300 mM NaCl were analyzed after 1 h and 5 days. We obtained up to 49 million pairs of short reads with an average length of 101 bp, identifying a total of 2416 differentially expressed genes (DEGs) based on the treatment and time of sampling. In salt-treated vs. control plants, the total number of up-regulated and down-regulated genes was 945 and 1471, respectively. The number of DEGs was higher at 5 days than at 1 h after salt treatment, as reflected in the number of transcription factors, which increased with time. We report a strong transcriptional reprogramming of genes involved in biological processes like oxidation-reduction, response to stress and response to abscisic acid (ABA), and cell wall organization. Transcript analyses by real-time RT-qPCR supported the RNA-seq results and shed light on the contribution of roots and shoots to the overall transcriptional response. In addition, it revealed a time-dependent response in the expression of the analyzed DEGs, including a quick (within 1 h) response for some genes, suggesting a \u201cstress-anticipatory preparedness\u201d in this highly salt-tolerant genotype
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