996 research outputs found

    On the equivalence of Eulerian and Lagrangian variables for the two-component Camassa-Holm system

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    The Camassa-Holm equation and its two-component Camassa-Holm system generalization both experience wave breaking in finite time. To analyze this, and to obtain solutions past wave breaking, it is common to reformulate the original equation given in Eulerian coordinates, into a system of ordinary differential equations in Lagrangian coordinates. It is of considerable interest to study the stability of solutions and how this is manifested in Eulerian and Lagrangian variables. We identify criteria of convergence, such that convergence in Eulerian coordinates is equivalent to convergence in Lagrangian coordinates. In addition, we show how one can approximate global conservative solutions of the scalar Camassa-Holm equation by smooth solutions of the two-component Camassa-Holm system that do not experience wave breaking

    Two-Photon Doppler cooling of alkaline-earth-metal and ytterbium atoms

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    A new possibility of laser cooling of alkaline-earth-metal and Ytterbium atoms using a two-photon transition is analyzed. We consider a 1S0^{1}S_{0} - 1S0^{1}S_{0} transition, with excitation in near resonance with the 1P1^{1}P_{1} level. This greatly increases the two-photon transition rate, allowing an effective transfer of momentum. The experimental implementation of this technique is discussed and we show that for Calcium, for example, two-photon cooling can be used to achieve a Doppler limit of 123 microKelvin. The efficiency of this cooling scheme and the main loss mechanisms are analyzed.Comment: 7 pages, 5 figure

    Targeting GATA4 for cardiac repair

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    Various strategies have been applied to replace the loss of cardiomyocytes in order to restore reduced cardiac function and prevent the progression of heart disease. Intensive research efforts in the field of cellular reprogramming and cell transplantation may eventually lead to efficient in vivo applications for the treatment of cardiac injuries, representing a novel treatment strategy for regenerative medicine. Modulation of cardiac transcription factor (TF) networks by chemical entities represents another viable option for therapeutic interventions. Comprehensive screening projects have revealed a number of molecular entities acting on molecular pathways highly critical for cellular lineage commitment and differentiation, including compounds targeting Wnt- and transforming growth factor beta (TGF beta)-signaling. Furthermore, previous studies have demonstrated that GATA4 and NKX2-5 are essential TFs in gene regulation of cardiac development and hypertrophy. For example, both of these TFs are required to fully activate mechanical stretch-responsive genes such as atrial natriuretic peptide and brain natriuretic peptide (BNP). We have previously reported that the compound 3i-1000 efficiently inhibited the synergy of the GATA4-NKX2-5 interaction. Cellular effects of 3i-1000 have been further characterized in a number of confirmatory in vitro bioassays, including rat cardiac myocytes and animal models of ischemic injury and angiotensin II-induced pressure overload, suggesting the potential for small molecule-induced cardioprotection.Peer reviewe

    Application of high-throughput sequencing for studying genomic variations in congenital heart disease

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    Congenital heart diseases (CHD) represent the most common birth defect in human. The majority of cases are caused by a combination of complex genetic alterations and environmental influences. In the past, many disease-causing mutations have been identified; however, there is still a large proportion of cardiac malformations with unknown precise origin. High-throughput sequencing technologies established during the last years offer novel opportunities to further study the genetic background underlying the disease. In this review, we provide a roadmap for designing and analyzing high-throughput sequencing studies focused on CHD, but also with general applicability to other complex diseases. The three main next-generation sequencing (NGS) platforms including their particular advantages and disadvantages are presented. To identify potentially disease-related genomic variations and genes, different filtering steps and gene prioritization strategies are discussed. In addition, available control datasets based on NGS are summarized. Finally, we provide an overview of current studies already using NGS technologies and showing that these techniques will help to further unravel the complex genetics underlying CHD

    The Relation between Attitudes toward Functional Foods and Satisfaction with Food-Related Life

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    Purpose – To assess the effect of attitudes towards functional foods (FF) on university students’ satisfaction with food-related life and to distinguish student typologies, considering that the attitudes towards FF are not homogeneous among consumers. Design/methodology - A survey was applied to 372 university students (mean age=20.4 years, SD=2.4) in southern Chile. The questionnaire included the Attitudes towards Functional Foods (AFF) questionnaire and the Satisfaction with Food-related Life (SWFL) scale, questions about consumption and knowledge about FF and socio-demographic characteristics. Findings – Using Confirmatory Factor Analysis (CFA) and Structural Equation Modelling, it was found that attitudes toward functional foods directly and significantly influence students’ satisfaction with food-related life. A cluster analysis applied to the Z-scores from the factors obtained by the CFA classified three typologies: Positive towards FF (36.3%), moderately positive towards FF (43.0%) and negative towards FF (20.7%). The positive towards FF type had a significantly greater SWFL score than the negative towards FF type. The types differ according to consumption and knowledge about FF. Research limitations/implications – This study was conducted in the context of only one country in South America. Originality/value – This study is the first that assesses the effect of AFF on satisfaction with food-related life in a sample of university students. Fostering positive attitudes towards FF will allow for a growth in the degree of satisfaction with food-related life of university students with features similar to those of the study sample

    Estrogens in the feces of the new-born calf

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    Em 10 bezerros recém-nascidos (4 machos e 6 fêmeas), foi examinado o conteúdo estrogênico das fezes dentro dos primeiros 11 dias de vida, com o auxílio de um teste biológico (teste de aumento de peso em útero de camundongo). Os valores médios situam-se até o terceiro dia de vida pós-parto como altamente significantes (P < 0,001), baixando sua significância para P < 0,05 no quarto dia quando os valores dos primeiros dias são comparados aos dos dias seguintes. Em 30% dos animais examinados já não se identificou qualquer traço de substância com ação estrogênica no terceiro dia de vida, aumentando a percentagem para 70% no quarto dia. No quinto dia não se identificou qualquer traço desta ação estrogênica em nenhum dos animais examinados. Com base nos exames feitos, concluiu-se que os estrógenos de origem materna são eliminados dentro dos primeiros dias de vida. Uma transmissão de estrógenos através do leite materno parece impossível.The estrogenic content of the feces of four male and six female calves, during the first 11 days of life, was measured by using the bioassay technique for uterine weight increase in immature mice. The estrogenic content of the feces of the calves was significantly higher (P < 0,001) until three days of age and higher (P < 0,05) on the fourth day than at subsequent ages. The presence of estrogenic substances in the feces was not detected in three of the ten calves (30%) at the three days of age. This percentage increased to 70% on the fourth day. By the fifth day, estrogenic activity was not detected in the feces of any of the calves examined. These results indicate that estrogens of maternal origin are eliminated within the first days of life. Thus, it does appear reasonable that estrogens are not provided by the colostrum or milk

    Magnetic trapping of metastable 3P2^3P_2 atomic strontium

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    We report the magnetic trapping of metastable 3P2^3P_2 atomic strontium. Atoms are cooled in a magneto-optical trap (MOT) operating on the dipole allowed 1S0−1P1^1S_0-^1P_1 transition at 461 nm. Decay via 1P1→1D2→3P2^1P_1\to {^1D_2}\to {^3P_2} continuously loads a magnetic trap formed by the quadrupole magnetic field of the MOT. Over 10810^8 atoms at a density of 8×1098 \times 10^9 cm−3^{-3} and temperature of 1 mK are trapped. The atom temperature is significantly lower than what would be expected from the kinetic and potential energy of atoms as they are transferred from the MOT. This suggests that thermalization and evaporative cooling are occurring in the magnetic trap.Comment: This paper has been accepted by PR

    Diagnostic Performance of Kwak, EU, ACR, and Korean TIRADS as Well as ATA Guidelines for the Ultrasound Risk Stratification of Non-Autonomously Functioning Thyroid Nodules in a Region with Long History of Iodine Deficiency: A German Multicenter Trial

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    Simple Summary In Germany, thyroid nodules can be detected by ultrasound examinations in over 30% of the adult population, mainly as a result of prolonged nutritive iodine deficiency. Although only a small proportion of the nodules are malignant, it is important to have a reliable examination method that not only can detect these few thyroid carcinomas with a high degree of certainty, but also not be unnecessarily invasive for the much larger number of benign nodules. Ultrasound is the method of choice, and ultrasound-based risk stratification systems are important tools in clinical care. However, many different systems have been introduced within the last decade. The aim of this study was to evaluate five common ultrasound risk stratification systems for their diagnostic accuracy of thyroid nodules from an area with long history of iodine deficiency. Abstract Germany has a long history of insufficient iodine supply and thyroid nodules occur in over 30% of the adult population, the vast majority of which are benign. Non-invasive diagnostics remain challenging, and ultrasound-based risk stratification systems are essential for selecting lesions requiring further clarification. However, no recommendation can yet be made about which system performs the best for iodine deficiency areas. In a German multicenter approach, 1211 thyroid nodules from 849 consecutive patients with cytological or histopathological results were enrolled. Scintigraphically hyperfunctioning lesions were excluded. Ultrasound features were prospectively recorded, and the resulting classifications according to five risk stratification systems were retrospectively determined. Observations determined 1022 benign and 189 malignant lesions. The diagnostic accuracies were 0.79, 0.78, 0.70, 0.82, and 0.79 for Kwak Thyroid Imaging Reporting and Data System (Kwak-TIRADS), American College of Radiology (ACR) TI-RADS, European Thyroid Association (EU)-TIRADS, Korean-TIRADS, and American Thyroid Association (ATA) Guidelines, respectively. Receiver Operating Curves revealed Areas under the Curve of 0.803, 0.795, 0.800, 0.805, and 0.801, respectively. According to the ATA Guidelines, 135 thyroid nodules (11.1%) could not be classified. Kwak-TIRADS, ACR TI-RADS, and Korean-TIRADS outperformed EU-TIRADS and ATA Guidelines and therefore can be primarily recommended for non-autonomously functioning lesions in areas with a history of iodine deficiency

    Expanding understanding of optical variability in Lake Superior with a 4-year dataset

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    Lake Superior is one of the largest freshwater lakes on our planet, but few optical observations have been made to allow for the development and validation of visible spectral satellite remote sensing products. The dataset described here focuses on coincidently observing inherent and apparent optical properties along with biogeochemical parameters. Specifically, we observe remote sensing reflectance, absorption, scattering, backscattering, attenuation, chlorophyll concentration, and suspended particulate matter over the ice-free months of 2013&ndash;2016. The dataset substantially increases the optical knowledge of the lake. In addition to visible spectral satellite algorithm development, the dataset is valuable for characterizing the variable light field, particle, phytoplankton, and colored dissolved organic matter distributions, and helpful in food web and carbon cycle investigations. The compiled data can be freely accessed at https://seabass.gsfc.nasa.gov/archive/URI/Mouw/LakeSuperior/
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