1,014 research outputs found

    Surveying Caulerpa (Chlorophyta) species along the shores of the eastern Mediterranean

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    Caulerpa (Chlorophyta) species inhabiting intertidal and shallow subtidal areas along the Israeli Mediterranean shores were surveyed (i.e. presence/absence) on a seasonal basis from 2007-2009. We recorded the presence of three speciesC. prolifera, C. mexicana, and C. scalpelliformis. These species were noticeable in autumn and inconspicuous during winter, thus, revealing seasonality and population dynamics. There were no indications of well-known invasive species such as Caulerpa racemosa var.cylindracea and Caulerpa taxifolia. This study is the first of a kind that assesses the geographical distribution and seasonality of the genus Caulerpa along the Israeli shores

    Inhibition of ornithine decarboxylase activity by follicle stimulating hormone in primary culture of rat Sertoli cells

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    The effect of follicle stimulating hormone on the activity of ornithine decarboxylase (ODC) was determined in primary culture of rat Sertoli cells. Three different FSH preparations (NIH oFSH-S-15, S-16, and eFSH) inhibited ODC activity in rat Sertoli cells under different media conditions. The inhibition was both time- and dose-dependent. The mechanism of the FSH inhibitory effect was studied using dibutyryl cyclic adenosine monophosphate (dbcAMP), 1-methyl-3-isobutylxanthine (MIX), forskolin, and isoproterenol. All of these agents, known to elevate cellular cAMP levels, inhibited ODC activity in cultured rat Sertoli cells. The combined effect of each of these substances plus FSH was either greater than, or equal to, that of FSH alone, and was not additive. Dibutyryl cyclic guanosine monophosphate had no effect on the ODC activity. These findings suggest that FSH inhibition of ODC activity in the rat Sertoli cell may be mediated by cAMP

    Designing the microstructure of routines

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    Abstract Coordinating organizational routines is a strategic challenge in contexts ranging from healthcare to software development. Yet, we have few theories of the design of routines. This paper compares field data on routines at two Korean restaurants to theorize their design. We identified a core coordination challenge as the need for concurrency—the simultaneous coordination of diverse activities of indeterminate order. The restaurants enabled concurrency using distinct solutions for providing information to agents about their routine activities. We normatively frame these solutions as firm-level strategies for coordinating routines based on uniformity (providing information about fixed sequences of activities) or compatibility (providing information about particular performances of activities). While prior work assumes strategies for coordinating routines depend on extensive codification, our framework shows how extensive codification is specific to a uniformity strategy. We argue that the compatibility strategy characterizes how firms increasingly coordinate routines amid blurring firm boundaries and discuss implications for landscape design.https://deepblue.lib.umich.edu/bitstream/2027.42/152263/1/41469_2019_Article_58.pd

    Luxury-focused carbon taxation improves fairness of climate policy

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    Equitable climate policies are required for a just and rapid energy transition. A widely discussed climate policy instrument is carbon taxes. Previous studies of the distributional implications of carbon taxation focused on uniform carbon taxes across sectors. Differentiated tax rates across goods and services received less attention. Here we model an alternative carbon tax design accounting for the distribution of household consumption and carbon footprints across 88 countries covering the global north and south. The policy distinguishes luxury and basic consumption and sets higher carbon prices for luxury. The policy reduces yearly global household emissions by 6% compared with no policy and inequalities are reduced compared with no policy and compared with a uniform carbon tax. By 2050, the policy saves around 100 gigatonnes carbon dioxide equivalents, which is 75% of what is needed for households to remain within a 2° consistent climate pathway

    Translation Directed by Hepatitis A Virus IRES in the Absence of Active eIF4F Complex and eIF2

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    Abstract Translation directed by several picornavirus IRES elements can usually take place after cleavage of eIF4G by picornavirus proteases 2A pro or L pro . The hepatitis A virus (HAV) IRES is thought to be an exception to this rule because it requires intact eIF4F complex for translation. In line with previous results we report that poliovirus (PV) 2A pro strongly blocks protein synthesis directed by HAV IRES. However, in contrast to previous findings we now demonstrate that eIF4G cleavage by footand-mouth disease virus (FMDV) L pro strongly stimulates HAV IRES-driven translation. Thus, this is the first observation that 2A pro and L pro exhibit opposite effects to what was previously thought to be the case in HAV IRES. This effect has been observed both in hamster BHK and human hepatoma Huh7 cells. In addition, this stimulation of translation is also observed in cell free systems after addition of purified L pro . Notably, in presence of this FMDV protease, translation directed by HAV IRES takes place when eIF2a has been inactivated by phosphorylation. Our present findings clearly demonstrate that protein synthesis directed by HAV IRES can occur when eIF4G has been cleaved and after inactivation of eIF2. Therefore, translation directed by HAV IRES without intact eIF4G and active eIF2 is similar to that observed with other picornavirus IRESs

    Validity, practical utility, and reliability of the activPAL in preschool children

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    <p>Purpose: With the increasing global prevalence of childhood obesity, it is important to have appropriate measurement tools for investigating factors (e.g. sedentary time) contributing to positive energy balance in early childhood. For pre-school children, single unit monitors such as the activPALTM are promising. However, validation is required as activity patterns differ from adults.</p> <p>Methods: Thirty pre-school children participated in a validation study. Children were videoed for one hour undertaking usual nursery activity while wearing an activPALTM. Video (criterion method) was analyzed on a second-by-second basis to categorise posture and activity. This was compared with the corresponding activPALTM output. In a subsequent sub-study investigating practical utility and reliability, 20 children wore an activPALTM for seven consecutive 24-hour periods.</p> <p>Results: A total of 97,750 seconds of direct observation from 30 children were categorized as sit/lie (46%), stand (35%), walk (16%); with 3% of time in nonsit/lie/upright postures (e.g. crawl/crouch/kneel-up). Sensitivity for the overall total time matched seconds detected as activPALTM ‘sit/lie’ was 86.7%, specificity 97.1%, and positive predictive value (PPV) 96.3%. For individual children, the median (interquartile range) sensitivity for activPALTM sit/lie was 92.8% (76.1-97.4), specificity 97.3% (94.9-99.2), PPV 97.0% (91.5-99.1). The activPALTM underestimated total time spent sitting (mean difference -4.4%, p<0.01), and overestimated time standing (mean difference 7.1%, p<0.01). There was no difference in overall % time categorised as ‘walk’ (p=0.2). The monitors were well tolerated by children during a seven day period of free-living activity. In the reliability study, at least five days of monitoring were required to obtain an intraclass correlation coefficient of ≥0.8 for time spent sit/lie according to activPALTM output.</p> <p>Conclusion: The activPAL had acceptable validity, practical utility, and reliability for the measurement of posture and activity during freeliving activities in pre-school children.</p&gt

    Drop impact upon micro- and nanostructured superhydrophobic surfaces

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    We experimentally investigate drop impact dynamics onto different superhydrophobic surfaces, consisting of regular polymeric micropatterns and rough carbon nanofibers, with similar static contact angles. The main control parameters are the Weber number \We and the roughness of the surface. At small \We, i.e. small impact velocity, the impact evolutions are similar for both types of substrates, exhibiting Fakir state, complete bouncing, partial rebouncing, trapping of an air bubble, jetting, and sticky vibrating water balls. At large \We, splashing impacts emerge forming several satellite droplets, which are more pronounced for the multiscale rough carbon nanofiber jungles. The results imply that the multiscale surface roughness at nanoscale plays a minor role in the impact events for small \We \apprle 120 but an important one for large \We \apprge 120. Finally, we find the effect of ambient air pressure to be negligible in the explored parameter regime \We \apprle 150Comment: 8 pages, 7 figure

    A Gauge Invariant Unitary Theory for Pion Photoproduction

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    A covariant, unitary and gauge invariant theory for pion photoproduction on a single nucleon is presented. To achieve gauge invariance at the operator level one needs to include both the πN\pi N and γπN\gamma\pi N thresholds. The final amplitude can be written in terms of a distorted wave in the final πN\pi N channel provided one includes additional diagrams to the standard Born term in which the photon is coupled to the final state pion and nucleon. These additional diagrams are required in order to satisfy gauge invariance.Comment: 4 pages, LaTeX, 1 figure as a separate uuencoded compressed tar fil

    Decay of correlations for maps with uniformly contracting fibers and logarithm law for singular hyperbolic attractors

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    We consider two dimensional maps preserving a foliation which is uniformly contracting and a one dimensional associated quotient map having exponential convergence to equilibrium (iterates of Lebesgue measure converge exponentially fast to physical measure). We prove that these maps have exponential decay of correlations over a large class of observables. We use this result to deduce exponential decay of correlations for the Poincare maps of a large class of singular hyperbolic flows. From this we deduce logarithm laws for these flows.Comment: 39 pages; 03 figures; proof of Theorem 1 corrected; many typos corrected; improvements on the statements and comments suggested by a referee. Keywords: singular flows, singular-hyperbolic attractor, exponential decay of correlations, exact dimensionality, logarithm la

    Сучасний стан і проблеми управління залізничним транспортом України

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    Проаналізовано стан і тенденції розвитку залізничного транспорту. Розглянуті основні завдання державного регулювання галузі.Проанализировано состояние и тенденции развития железнодорожного транспорта. Рассмотренны основные задания государственного регулирования отрасли.The condition and trends of railway transport has been anilized. The main tasks of state regulation of railway transport has been considereted
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