6,733 research outputs found
Annual fecundity, batch fecundity, and oocyte atresia of Atka mackerel (Pleurogrammus monopterygius) in Alaskan waters
Annual potential fecundity, batch fecundity, and oocyte
atresia were estimated for Atka mackerel (Pleurogrammus monopterygius) collected in Alaskan waters during 1993−94. Atka mackerel were assumed to be determinate spawners on the basis of decreasing fecundity after batch spawning events. Histological examination of the ovaries indicated that oocytes in the vitellogenic stage and higher had been
spawned in the current spawning season. For an average female of 40 cm, potential annual fecundity was estimated to be 41,994 eggs, average batch size (i.e., batch fecundity) was estimated to be 6689 eggs, and there were 6.13 batches per spawning season. Atresia was estimated by
examining postspawning specimens and was found to be substantial. The average amount of atresia for a 40-cm fish was estimated to be 11,329 eggs, resulting in an estimated realized fecundity of only 30,664 eggs and 4.64 batches of eggs per spawning season
Learning physics in context: a study of student learning about electricity and magnetism
This paper re-centres the discussion of student learning in physics to focus
on context. In order to do so, a theoretically-motivated understanding of
context is developed. Given a well-defined notion of context, data from a novel
university class in electricity and magnetism are analyzed to demonstrate the
central and inextricable role of context in student learning. This work sits
within a broader effort to create and analyze environments which support
student learning in the sciencesComment: 36 pages, 4 Figure
Validation of gyrokinetic modelling of light impurity transport including rotation in ASDEX Upgrade
Upgraded spectroscopic hardware and an improved impurity concentration
calculation allow accurate determination of boron density in the ASDEX Upgrade
tokamak. A database of boron measurements is compared to quasilinear and
nonlinear gyrokinetic simulations including Coriolis and centrifugal rotational
effects over a range of H-mode plasma regimes. The peaking of the measured
boron profiles shows a strong anti-correlation with the plasma rotation
gradient, via a relationship explained and reproduced by the theory. It is
demonstrated that the rotodiffusive impurity flux driven by the rotation
gradient is required for the modelling to reproduce the hollow boron profiles
at higher rotation gradients. The nonlinear simulations validate the
quasilinear approach, and, with the addition of perpendicular flow shear,
demonstrate that each symmetry breaking mechanism that causes momentum
transport also couples to rotodiffusion. At lower rotation gradients, the
parallel compressive convection is required to match the most peaked boron
profiles. The sensitivities of both datasets to possible errors is
investigated, and quantitative agreement is found within the estimated
uncertainties. The approach used can be considered a template for mitigating
uncertainty in quantitative comparisons between simulation and experiment.Comment: 19 pages, 11 figures, accepted in Nuclear Fusio
Qualitative protocol for understanding the contribution of Australian policy in the urban planning, justice, energy and environment sectors to promoting health and health equity
Introduction: A well-established body of literature demonstrates that health and equity are strongly influenced by the consequences of governments’ policy and resultant actions (or inactions) outside the health sector. Consequently, the United Nations, and its agency the WHO, have called for national leadership and whole-of-government action to understand and address the health impacts of policies in all sectors. This research responds to that call by investigating how policymaking in four sectors—urban planning, justice, energy and environment—may influence the social determinants of health and health equity (SDH/HE). Methods and analysis: The research design is informed by a critical qualitative approach. Three successive stages are included in the design. The first involves analysing all strategic policy documents and selected legislative documents from the four sectors (n=583). The document analysis is based on a coding framework developed to identify alignment between the documents and the SDH/HE. Two policies that demonstrate good practice in regard to SDH/HE will be selected from each sector during the second stage for embedded case study analysis (total n=8). This is intended to illuminate which factors have supported recognition and action on SDH/HE in the selected policies. The third stage involves progressive theoretical integration and development to understand political and institutional facilitators and barriers to action on SDH/HE, both within and between sectors. Ethics and dissemination: The research will provide much needed evidence about how coherent whole-of-government action on SDH/HE can be advanced and contribute knowledge about how health-enhancing policy activity in the four sectors may be optimised. Learnings from the research will be shared via a project advisory group, policy briefings, academic papers, conference presentations and research symposia. Ethics approval has been secured for the embedded case studies, which involve research participants
I-mode studies at ASDEX Upgrade: L-I and I-H transitions, pedestal and confinement properties
The I-mode is a plasma regime obtained when the usual L-H power threshold is high, e.g.
with unfavourable ion
B
∇
direction. It is characterised by the development of a temperature
pedestal while the density remains roughly as in the L-mode. This leads to a confinement
improvement above the L-mode level which can sometimes reach H-mode values. This
regime, already obtained in the ASDEX Upgrade tokamak about two decades ago, has
been studied again since 2009 taking advantage of the development of new diagnostics
and heating possibilities. The I-mode in ASDEX Upgrade has been achieved with different
heating methods such as NBI, ECRH and ICRF. The I-mode properties, power threshold,
pedestal characteristics and confinement, are independent of the heating method. The power
required at the L-I transition exhibits an offset linear density dependence but, in contrast
to the L-H threshold, depends weakly on the magnetic field. The L-I transition seems to be
mainly determined by the edge pressure gradient and the comparison between ECRH and
NBI induced L-I transitions suggests that the ion channel plays a key role. The I-mode often
evolves gradually over a few confinement times until the transition to H-mode which offers
a very interesting situation to study the transport reduction and its link with the pedestal
formation. Exploratory discharges in which
n
=
2 magnetic perturbations have been applied
indicate that these can lead to an increase of the I-mode power threshold by flattening the edge
pressure at fixed heating input power: more heating power is necessary to restore the required
edge pressure gradient. Finally, the confinement properties of the I-mode are discussed in
detail.European Commission (EUROfusion 633053
TGFβ activation primes canonical Wnt signaling through the downregulation of AXIN2
OBJECTIVES: Aberrant activation of Wnt signaling has been observed in systemic sclerosis (SSc) affected tissues. This study aimed to determine the role of transforming growth factor (TGF)β in driving the increased Wnt signaling, through modulation of AXIN2, a critical regulator of Wnt canonical pathway. METHODS: Canonical Wnt signaling activation was analyzed by TOPFlash TCF/LEF promoter assays. AXIN2 was evaluated in vitro by analysis of AXIN2 primary/mature transcripts expression and decay, TβRI blockade, siRNA-mediated TTP-1 depletion and through XAV-939-mediated AXIN2 stabilisation. In vivo, Axin2 mRNA and protein expression was determined in skin and lung biopsies from TβRIIΔk-fib transgenic mice and littermate controls. RESULTS: SSc fibroblasts display increased response to canonical Wnt ligands despite basal levels of Wnt signaling comparable to healthy control (HC) fibroblasts in vitro. Notably, we show that SSc fibroblasts express reduced basal expression of AXIN2, which is caused by endogenous TGFβ-dependent increase of AXIN2 mRNA decay. Accordingly, we observed that TGFβ decreased AXIN2 expression both in vitro in HC fibroblasts and in vivo, employing TβRIIΔk-fib transgenic mice. Additionally, we demonstrate by AXIN2 loss and gain of function experiments, that the TGFβ-induced increased response to Wnt activation characteristic of SSc fibroblasts is dependent on reduced AXIN2 bioavailability. CONCLUSIONS: This study highlights the importance of reduced AXIN2 bioavailability in mediating the increased canonical Wnt response observed in SSc fibroblasts. This novel mechanism extends our understanding of the processes involved in Wnt/β-catenin-driven pathology and supports the rationale for targeting the TGFβ pathway to regulate the aberrant Wnt signaling observed during fibrosis. This article is protected by copyright. All rights reserved
Program trace optimization
This is the author accepted manuscript. The final version is available from Springer via the DOI in this record.Paper to be presented at the Fifteenth International Conference on Parallel Problem Solving from Nature (PPSN XV), Coimbra, Portugal on 8-12 September 2018.We introduce Program Trace Optimization (PTO), a system for `universal heuristic optimization made easy'. This is achieved by strictly separating the problem from the search algorithm. New problem definitions and new generic search algorithms can be added to PTO easily and independently, and any algorithm can be used on any problem. PTO automatically extracts knowledge from the problem specifi cation and designs search operators for the problem. The operators designed by PTO for standard representations coincide with existing ones, but PTO automatically designs operators for arbitrary representations
Early childhood anaemia more than doubles the risk of developmental vulnerability at school-age among Aboriginal and Torres Strait Islander children of remote Far North Queensland: Findings of a retrospective cohort study
AIMS:Early childhood anaemia, usually attributed to iron deficiency, is associated with persistent detrimental effects on child development. This study investigates the association of anaemia between age six and 23 months with indicators of childhood development at school-age among children of remote Aboriginal and Torres Strait Islander communities of Far North Queensland. METHODS:The triennial Australian Early Development Census (AEDC) encompasses five domains of early childhood development-physical health and wellbeing, social competence, emotional maturity, language and cognitive skills (school-based), communication skills and general knowledge. AEDC 2012 and 2015 assessments were linked with health information for children and their mothers from remote Aboriginal and Torres Strait Islander communities of Far North Queensland. RESULTS:AEDC assessments were available for 250 children who had measurements of haemoglobin recorded at age 6 to 23 months. More children who had had early childhood anaemia (n = 66/143, 46.2%, [37.9%, 54.4%]) were developmentally vulnerable on two or more domains compared to those who had not been anaemic (n = 25/107, 23.4% [15.2%, 31.5%], P < .001). Multivariable analysis confirmed that early childhood anaemia more than doubled the risk of developmental vulnerability (OR 2.2 [1.1, 4.3] P = .020) at school age. CONCLUSIONS:Early childhood anaemia is a risk factor for developmental vulnerability at school-age in this setting. Interventions combining nutrition promotion and multi-micronutrient food fortification, are effective in prevention of early childhood anaemia. Such interventions could also improve early childhood development and subsequent educational achievement.Dympna Leonard, Petra Buettner, Fintan Thompson, Maria Makrides, Robyn McDermot
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