CaMKII-dependent regulation of cardiac Na(+) homeostasis.

Na(+) homeostasis is a key regulator of cardiac excitation and contraction. The cardiac voltage-gated Na(+) channel, NaV1.5, critically controls cell excitability, and altered channel gating has been implicated in both inherited and acquired arrhythmias. Ca(2) (+)/calmodulin-dependent protein kinase II (CaMKII), a serine/threonine kinase important in cardiac physiology and disease, phosphorylates NaV1.5 at multiple sites within the first intracellular linker loop to regulate channel gating. Although CaMKII sites on the channel have been identified (S516, T594, S571), the relative role of each of these phospho-sites in channel gating properties remains unclear, whereby both loss-of-function (reduced availability) and gain-of-function (late Na(+) current, INa L) effects have been reported. Our review highlights investigating the complex multi-site phospho-regulation of NaV1.5 gating is crucial to understanding the genesis of acquired arrhythmias in heart failure (HF) and CaMKII activated conditions. In addition, the increased Na(+) influx accompanying INa L may also indirectly contribute to arrhythmia by promoting Ca(2) (+) overload. While the precise mechanisms of Na(+) loading during HF remain unclear, and quantitative analyses of the contribution of INa L are lacking, disrupted Na(+) homeostasis is a consistent feature of HF. Computational and experimental observations suggest that both increased diastolic Na(+) influx and action potential prolongation due to systolic INa L contribute to disruption of Ca(2) (+) handling in failing hearts. Furthermore, simulations reveal a synergistic interaction between perturbed Na(+) fluxes and CaMKII, and confirm recent experimental findings of an arrhythmogenic feedback loop, whereby CaMKII activation is at once a cause and a consequence of Na(+) loading

The decoherence criterion

The decoherence mechanism signals the limits beyond which the system dynamics approaches the classical behavior. We show that in some cases decoherence may also signal the limits beyond which the system dynamics has to be described by quantum field theory, rather than by quantum mechanics.Comment: revised paper, in print on Mod. Phys. Lett.

Measuring physical inactivity:do current measures provide an accurate view of "sedentary" video game time?

BACKGROUND: Measures of screen time are often used to assess sedentary behaviour. Participation in activity-based video games (exergames) can contribute to estimates of screen time, as current practices of measuring it do not consider the growing evidence that playing exergames can provide light to moderate levels of physical activity. This study aimed to determine what proportion of time spent playing video games was actually spent playing exergames. METHODS: Data were collected via a cross-sectional telephone survey in South Australia. Participants aged 18 years and above (n = 2026) were asked about their video game habits, as well as demographic and socioeconomic factors. In cases where children were in the household, the video game habits of a randomly selected child were also questioned. RESULTS: Overall, 31.3% of adults and 79.9% of children spend at least some time playing video games. Of these, 24.1% of adults and 42.1% of children play exergames, with these types of games accounting for a third of all time that adults spend playing video games and nearly 20% of children's video game time. CONCLUSIONS: A substantial proportion of time that would usually be classified as "sedentary" may actually be spent participating in light to moderate physical activity

On topological defect formation in the process of symmetry breaking phase transitions

By resorting to some results in quantum field theories with spontaneous breakdown of symmetry we show that an explanation based on microscopic dynamics can be given of the fact that topological defect formation is observed during the process of non-equilibrium phase transitions characterized by a non-zero order parameter. We show that the Nambu-Goldstone particle acquires an effective non-zero mass due to the boundary (finite volume) effects and this is related with the size of the defect. We also relate such volume effect with temperature effect.Comment: 12 pages, no figure

Meningkatkan Pemahaman Mahasiswa Pendidikan Matematika FKIP UPS Tegal pada Konsep Distribusi Peluang Khusus Melalui Pembelajaran Kooperatif Model STAD

Perkuliahan Statistika Matematika I dengan model pembelajaran konvensional dibantu dengan buku ajar pada Program Studi Pendidikan Matematika FKIP UPS Tegal tidak signifikan meningkatkan pemahaman mahasiswa semester IV T.A 2007-2008. Mahasiswa cenderung pasif dalam proses pembelajaran, kesiapan mahasiswa mengikuti perkuliahan rendah, dan kurangnya tanggung jawab mahasiswa akan pembelajarannya menyebabkan hasil belajar mereka masih rendah. Dari hasil tes yang diberikan menunjukkan masih terdapat banyak kesalahan pada penerapan konsep, dan kesalahan dalam proses penyelesaian masalah. Penelitian ini hendak mengatasi permasalahan pembelajaran Statistika Matematika I pada Progdi PMTK FKIP UPS Tegal dengan menerapkan pendekatan pembelajaran kooperatif model STAD, yang diimplementasikan pada pembelajaran konsep Distribusi Peluang Khusus. Prosedur penelitian mengacu pada model siklus Kemmis dan Mc Taggart, dan direncanakan sebanyak dua siklus Pengamatan meliputi aktivitasi mahasiswa dalam pembelajaran, motivasi belajar, dan hasil belajar. Instrumen penelitian menggunakan instrumen observasi peer evaluation, instrumen observasi kinerja kelompok, angket motivasi, dan tes. Data yang dikumpulkan pada setiap siklus penelitian kemudian dianalisis secara deskriptif dengan menggunakan persentase untuk melihat kecenderungan yang terjadi. Implikasi pelaksanaan siklus kedua ditunjukkan dengan adanya peningkatan aktivitasi mahasiswa dalam pembelajaran Distribusi Peluang Khusus. Prosentase mahasiswa yang memberikan kontribusi pada kelompok minimal cukup memuaskan meningkat dari 68 % menjadi 83% , sementara prosentase kelompok dengan kinerja tinggi meningkat 60 %. Motivasi belajar mahasiswa meningkat dari 92% menjadi 96%, namun pada aspek tes anxienty tidak mengalami peningkatan. Hasil belajar mahasiswa meningkat terlihat dari banyaknya mahasiswa yang memahami konsep minimal mendekati sepenuhnya meningkat sebesar 73%, yang menggunakan strategi pemecahan masalah minimal mendekati sepenuhnya meningkat 53%, dan yang menggunakan prosedur minimal mendekati sepenuhnya meningkat 40%. Kata kunci : pembelajaran kooperatif, STA

The supermassive black hole mass - S\'ersic index relations for bulges and elliptical galaxies

Scaling relations between supermassive black hole mass, M_BH, and host galaxy properties are a powerful instrument for studying their coevolution. A complete picture involving all of the black hole scaling relations, in which each relation is consistent with the others, is necessary to fully understand the black hole-galaxy connection. The relation between M_BH and the central light concentration of the surrounding bulge, quantified by the S\'ersic index n, may be one of the simplest and strongest such relations, requiring only uncalibrated galaxy images. We have conducted a census of literature S\'ersic index measurements for a sample of 54 local galaxies with directly measured M_BH values. We find a clear M_BH - n relation, despite an appreciable level of scatter due to the heterogeneity of the data. Given the current M_BH - L_sph and the L_sph - n relations, we have additionally derived the expected M_BH - n relations, which are marginally consistent at the 2 sigma level with the observed relations. Elliptical galaxies and the bulges of disc galaxies are each expected to follow two distinct bent M_BH - n relations due to the S\'ersic/core-S\'ersic divide. For the same central light concentration, we predict that M_BH in the S\'ersic bulges of disc galaxies are an order magnitude higher than in S\'ersic elliptical galaxies if they follow the same M_BH - L_sph relation.Comment: 12 pages, 6 figures, 5 tables, accepted for publication in MNRA

Premutation in the Fragile X Mental Retardation 1 (FMR1) Gene Affects Maternal Zn-milk and Perinatal Brain Bioenergetics and Scaffolding.

Fragile X premutation alleles have 55-200 CGG repeats in the 5' UTR of the FMR1 gene. Altered zinc (Zn) homeostasis has been reported in fibroblasts from >60 years old premutation carriers, in which Zn supplementation significantly restored Zn-dependent mitochondrial protein import/processing and function. Given that mitochondria play a critical role in synaptic transmission, brain function, and cognition, we tested FMRP protein expression, brain bioenergetics, and expression of the Zn-dependent synaptic scaffolding protein SH3 and multiple ankyrin repeat domains 3 (Shank3) in a knock-in (KI) premutation mouse model with 180 CGG repeats. Mitochondrial outcomes correlated with FMRP protein expression (but not FMR1 gene expression) in KI mice and human fibroblasts from carriers of the pre- and full-mutation. Significant deficits in brain bioenergetics, Zn levels, and Shank3 protein expression were observed in the Zn-rich regions KI hippocampus and cerebellum at PND21, with some of these effects lasting into adulthood (PND210). A strong genotype × age interaction was observed for most of the outcomes tested in hippocampus and cerebellum, whereas in cortex, age played a major role. Given that the most significant effects were observed at the end of the lactation period, we hypothesized that KI milk might have a role at compounding the deleterious effects on the FMR1 genetic background. A higher gene expression of ZnT4 and ZnT6, Zn transporters abundant in brain and lactating mammary glands, was observed in the latter tissue of KI dams. A cross-fostering experiment allowed improving cortex bioenergetics in KI pups nursing on WT milk. Conversely, WT pups nursing on KI milk showed deficits in hippocampus and cerebellum bioenergetics. A highly significant milk type × genotype interaction was observed for all three-brain regions, being cortex the most influenced. Finally, lower milk-Zn levels were recorded in milk from lactating women carrying the premutation as well as other Zn-related outcomes (Zn-dependent alkaline phosphatase activity and lactose biosynthesis-whose limiting step is the Zn-dependent β-1,4-galactosyltransferase). In premutation carriers, altered Zn homeostasis, brain bioenergetics and Shank3 levels could be compounded by Zn-deficient milk, increasing the risk of developing emotional and neurological/cognitive problems and/or FXTAS later in life

Keefektifan model pembelajaran two stay two stray terhadap self-confidence dan prestasi belajar matematika

The purpose of this study is to describe: (1) Two Stay Two Stray learning model is more effective than conventional learning models of students' self-confidence. (2) the Two Stay Two Stray learning model is more effective than the conventional learning models of students' learning achievement. (3) there are differences in self-confidence and mathematics learning achievement between students taught using the Two Stay Two Stray learning model and those taught using conventional learning models. (4) Two Stay Two Stray learning models are more effective than conventional learning models of students' self-confidence and mathematics learning achievement. Data collection techniques carried out in the experimental class, namely class VII C and class VII E using tests, and questionnaires. The learning achievement test instrument consists of 25 multiple choice questions, the questionnaire instrument consists of 25 statement items. The test instruments and questionnaires were first tested in the pilot class, class VII A to determine the validity and reliability. Data analysis techniques used with a significance level of 5% are the right hand one-tailed t test, the Manova one-way test, and the τ2– Hotelling test with a significance level of 5%. The results showed that: (1) Two Stay Two Tray learning model is more effective than those taught using conventional learning models of students' self confidence. (2) Two Stay Two Tray learning models are more effective than those taught using conventional learning models on student learning achievement. (3) There is a difference in self-confidence and learning achievement between students taught using the Two Stay Two Stray learning model and those taught using the conventional model. (4) The Two Stay Two Stray learning model is more effective than the conventional model of self-confidence and mathematics learning achievement in the basic methods of equation and linear inequality of one variable

The impact of socioeconomic status on arthritis and osteoporosis

Background: Low socioeconomic status has been shown to be associated with both osteoarthri s and rheumatoid arthri s, impac ng on outcomes and even the development of arthri s. However the associa on with osteoporosis has been less clear. The reasons for the associa on may be linked to socioeconomic status through educa onal aspects, income, employment type and even area of residence. Purpose: The purpose of this study was use a monthly surveillance and monitoring system to examine the prevalence of self-reported osteoarthri s, rheumatoid arthri  s and osteoporosis over  me and the associa  on with measures of socioeconomic status