Net community production of oxygen derived from in vitro and in situ 1-D modeling techniques in a cyclonic mesoscale eddy in the Sargasso Sea

© 2009 The Authors. This work is distributed under the Creative Commons Attribution 3.0 License. The definitive version was published in Biogeosciences 6 (2009): 1799-1810, doi:10.5194/bg-6-1799-2009It has been proposed that the disagreement traditionally reported between in vitro incubation and in situ estimates of oxygen net community production (NCP) could be explained, at least partially, by undersampling episodic pulses of net autotrophy associated with mesoscale dynamics. In this study we compare in vitro incubation estimates of net community production with in situ estimates, derived from oxygen profiles and a 1-D model, within a cyclonic eddy investigated in the Sargasso Sea in summer 2004. The in vitro NCP rates measured at the center of the eddy showed a shift from net autotrophy (7±3 mmol O2 m−2 d−1) to net heterotrophy (−25±5 mmol O2 m−2 d−1) from late June to early August. The model-derived NCP rates also showed a temporal decline (19±6 to −3±7 and 11±8 mmol O2 m−2 d−1), but they were systematically higher than the in vitro estimates and reported net autotrophy or balance for the sampling period. In this comparison episodic pulses in photosynthesis or respiration driven by mesoscale eddies can not explain the discrepancy between the in vitro and in situ estimates of NCP. This points to methodological artefacts or temporal or submesoscale variability as the mechanisms responsible for the disagreement between the techniques, at least in this dataset.B. Mourino-Carballido was supported by a Fulbright postdoctoral fellowship and the Isidro Parga Pondal program from the Galician government

Use of a marking rubric and self-assessment to provide feedforward to level 5 undergraduate Sport students: student perceptions, performance and marking efficiency

The aim of this study was to identify whether Level 5 Sport students find a rubric and self-assessment helpful in providing feedforward on a lab report, and if the rubric improved performance andmarking efficiency. A questionnaire was administered to 58 students in order to identify perceptions. Marking time, report grades and classification were compared with the previous year. A significant improvement in the report mark of 7% (ρ=0.029) from the previous year and an increase in the number of passes in the higher classifications, along with a 25-minute decrease in the mean marking time, were observed. Perceptions of the rubric were generally positive in terms of increasing students’ understanding of the assessment.The role of the rubric in the self-assessment process was beneficial, as it enabled students to understand what they were doing well and what they needed to improve. Overall, rubrics should be considered when implementing a laboratory-based practical assessment and report

Assessment of Skill and Portability in Regional Marine Biogeochemical Models: Role of Multiple Planktonic Groups

[1] Application of biogeochemical models to the study of marine ecosystems is pervasive, yet objective quantification of these models\u27 performance is rare. Here, 12 lower trophic level models of varying complexity are objectively assessed in two distinct regions (equatorial Pacific and Arabian Sea). Each model was run within an identical one-dimensional physical framework. A consistent variational adjoint implementation assimilating chlorophyll-a, nitrate, export, and primary productivity was applied and the same metrics were used to assess model skill. Experiments were performed in which data were assimilated from each site individually and from both sites simultaneously. A cross-validation experiment was also conducted whereby data were assimilated from one site and the resulting optimal parameters were used to generate a simulation for the second site. When a single pelagic regime is considered, the simplest models fit the data as well as those with multiple phytoplankton functional groups. However, those with multiple phytoplankton functional groups produced lower misfits when the models are required to simulate both regimes using identical parameter values. The cross-validation experiments revealed that as long as only a few key biogeochemical parameters were optimized, the models with greater phytoplankton complexity were generally more portable. Furthermore, models with multiple zooplankton compartments did not necessarily outperform models with single zooplankton compartments, even when zooplankton biomass data are assimilated. Finally, even when different models produced similar least squares model-data misfits, they often did so via very different element flow pathways, highlighting the need for more comprehensive data sets that uniquely constrain these pathways

Genotype and expression analysis of two inbred mouse strains and two derived congenic strains suggest that most gene expression is trans regulated and sensitive to genetic background

<p>Abstract</p> <p>Background</p> <p>Differences in gene expression may be caused by nearby DNA polymorphisms (<it>cis </it>regulation) or by interactions of gene control regions with polymorphic transcription factors (<it>trans </it>regulation). <it>Trans </it>acting loci are much harder to detect than <it>cis </it>acting loci and their effects are much more sensitive to genetic background.</p> <p>Results</p> <p>To quantify <it>cis </it>and <it>trans </it>regulation we correlated haplotype data with gene expression in two inbred mouse strains and two derived congenic lines. Upstream haplotype differences between the parental strains suggested that 30-43% of differentially expressed genes were differentially expressed because of <it>cis </it>haplotype differences. These <it>cis </it>regulated genes displayed consistent and relatively tissue-independent differential expression. We independently estimated from the congenic mice that 71-85% of genes were <it>trans </it>regulated. <it>Cis </it>regulated genes were associated with low p values (p < 0.005) for differential expression, whereas <it>trans </it>regulated genes were associated with values 0.005 < p < 0.05. The genes differentially expressed between congenics and controls were not a subset of those that were differentially expressed between the founder lines, showing that these were dependent on genetic background. For example, the cholesterol synthesis pathway was strongly differentially expressed in the congenic mice by indirect <it>trans </it>regulation but this was not observable in the parental mice.</p> <p>Conclusions</p> <p>The evidence that most gene regulation is <it>trans </it>and strongly influenced by genetic background, suggests that pathways that are modified by an allelic variant, may only exhibit differential expression in the specific genetic backgrounds in which they were identified. This has significant implications for the interpretation of any QTL mapping study.</p

Near-Earth plasma sheet boundary dynamics during substorm dipolarization.

We report on the large-scale evolution of dipolarization in the near-Earth plasma sheet during an intense (AL ~ -1000 nT) substorm on August 10, 2016, when multiple spacecraft at radial distances between 4 and 15 R E were present in the night-side magnetosphere. This global dipolarization consisted of multiple short-timescale (a couple of minutes) B z disturbances detected by spacecraft distributed over 9 MLT, consistent with the large-scale substorm current wedge observed by ground-based magnetometers. The four spacecraft of the Magnetospheric Multiscale were located in the southern hemisphere plasma sheet and observed fast flow disturbances associated with this dipolarization. The high-time-resolution measurements from MMS enable us to detect the rapid motion of the field structures and flow disturbances separately. A distinct pattern of the flow and field disturbance near the plasma boundaries was found. We suggest that a vortex motion created around the localized flows resulted in another field-aligned current system at the off-equatorial side of the BBF-associated R1/R2 systems, as was predicted by the MHD simulation of a localized reconnection jet. The observations by GOES and Geotail, which were located in the opposite hemisphere and local time, support this view. We demonstrate that the processes of both Earthward flow braking and of accumulated magnetic flux evolving tailward also control the dynamics in the boundary region of the near-Earth plasma sheet.Graphical AbstractMultispacecraft observations of dipolarization (left panel). Magnetic field component normal to the current sheet (BZ) observed in the night side magnetosphere are plotted from post-midnight to premidnight region: a GOES 13, b Van Allen Probe-A, c GOES 14, d GOES 15, e MMS3, g Geotail, h Cluster 1, together with f a combined product of energy spectra of electrons from MMS1 and MMS3 and i auroral electrojet indices. Spacecraft location in the GSM X-Y plane (upper right panel). Colorcoded By disturbances around the reconnection jets from the MHD simulation of the reconnection by Birn and Hesse (1996) (lower right panel). MMS and GOES 14-15 observed disturbances similar to those at the location indicated by arrows

Regional differences in modelled net production and shallow remineralization in the North Atlantic subtropical gyre

© The Author(s), 2012. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Biogeosciences 9 (2012): 2831-2846, doi:10.5194/bg-9-2831-2012.We used 5-yr concomitant data of tracer distribution from the BATS (Bermuda Time-series Study) and ESTOC (European Station for Time-Series in the Ocean, Canary Islands) sites to build a 1-D tracer model conservation including horizontal advection, and then compute net production and shallow remineralization rates for both sites. Our main goal was to verify if differences in these rates are consistent with the lower export rates of particulate organic carbon observed at ESTOC. Net production rates computed below the mixed layer to 110 m from April to December for oxygen, dissolved inorganic carbon and nitrate at BATS (1.34±0.79 mol O2 m−2, −1.73±0.52 mol C m−2 and −125±36 mmol N m−2) were slightly higher for oxygen and carbon compared to ESTOC (1.03±0.62 mol O2 m−2, −1.42±0.30 mol C m−2 and −213±56 mmol N m−2), although the differences were not statistically significant. Shallow remineralization rates between 110 and 250 m computed at ESTOC (−3.9±1.0 mol O2 m−2, 1.53±0.43 mol C m−2 and 38±155 mmol N m−2) were statistically higher for oxygen compared to BATS (−1.81±0.37 mol O2 m−2, 1.52±0.30 mol C m−2 and 147±43 mmol N m−2). The lateral advective flux divergence of tracers, which was more significant at ESTOC, was responsible for the differences in estimated oxygen remineralization rates between both stations. According to these results, the differences in net production and shallow remineralization cannot fully explain the differences in the flux of sinking organic matter observed between both stations, suggesting an additional consumption of non-sinking organic matter at ESTOC.B. Mourino was supported by the Ramon y Cajal program from the Spanish Minister of Science and Technology. Funding for this study was provided by the Xunta de Galicia under the research project VARITROP (09MDS001312PR, PI B. Mourino) and by the Ministerio de Ciencia e Innovation MOMAC project (CTM2008-05914/MAR)

An exploratory cluster randomised controlled trial of knowledge translation strategies to support evidence-informed decision-making in local governments (The KT4LG study)

Background: Childhood overweight and obesity is the most prevalent and, arguably, politically complex child health problem internationally. Governments, communities and industry have important roles to play, and are increasingly expected to deliver an evidence-informed system-wide prevention program. However, efforts are impeded by a lack of organisational access to and use of research evidence. This study aims to identify feasible, acceptable and ideally, effective knowledge translation (KT) strategies to increase evidence-informed decision making in local governments, within the context of childhood obesity prevention as a national policy priority.Methods/Design: This paper describes the methods for KT4LG, a cluster randomised controlled trial which is exploratory in nature, given the limited evidence base and methodological advances. KT4LG aims to examine a program of KT strategies to increase the use of research evidence in informing public health decisions in local governments. KT4LG will also assess the feasibility and acceptability of the intervention. The intervention program comprises a facilitated program of evidence awareness, access to tailored research evidence, critical appraisal skills development, networking and evidence summaries and will be compared to provision of evidence summaries alone in the control program. 28 local governments were randomised to intervention or control, using computer generated numbers, stratified by budget tertile (high, medium or low). Questionnaires will be used to measure impact, costs, and outcomes, and key informant interviews will be used to examine processes, feasibility, and experiences. Policy tracer studies will be included to examine impact of intervention on policies within relevant government policy documents.Discussion: Knowledge translation intervention studies with a focus on public health and prevention are very few in number. Thus, this study will provide essential data on the experience of program implementation and evaluation of a system-integrated intervention program employed within the local government public health context. Standardised programs of system, organisational and individual KT strategies have not been described or rigorously evaluated. As such, the findings will make a significant contribution to understanding whether a facilitated program of KT strategies hold promise for facilitating evidence-informed public health decision making within complex multisectoral government organisations.<br /