Inferring source regions and supply mechanisms of iron in the Southern Ocean from satellite chlorophyll data

Highlights • Shelf sediment iron source concentrated around coastal margins. • No large iron flux from sediments on shallow submerged plateaus in the open ocean. • Horizontal advection of iron more important than upwelling of iron at ocean fronts. • Western boundary currents major supply mechanism of iron for Sub-Antarctic Zone. Abstract Primary productivity is limited by the availability of iron over large areas of the global ocean. Changes in the supply of iron to these regions could have major impacts on primary productivity and the carbon cycle. However, source regions and supply mechanisms of iron to the global oceans remain poorly constrained. Shelf sediments are considered one of the largest sources of dissolved iron to the global ocean, and a large shelf sediment iron flux is prescribed in many biogeochemical models over all areas of bathymetry shallower than 1000 m. Here, we infer the likely location of shelf sediment iron sources in the Southern Ocean, by identifying where satellite chlorophyll concentrations are enhanced over shallow bathymetry (2 mg m−3 are only found within 50 km of a continental or island coastline. These results suggest that sedimentary iron sources only exist on continental and island shelves. Large sedimentary iron fluxes do not seem present on seamounts and submerged plateaus. Large chlorophyll blooms develop where the western boundary currents detach from the continental shelves, and turn eastward into the Sub-Antarctic Zone. Chlorophyll concentrations are enhanced along contours of sea surface height extending off the continental shelves, as shown by the trajectories of virtual water parcels in satellite altimetry data. These analyses support the hypothesis that bioavailable iron from continental shelves is entrained into western boundary currents, and advected into the Sub-Antarctic Zone along the Dynamical Subtropical Front. Our results indicate that upwelling at fronts in the open ocean is unlikely to deliver iron to the ocean surface from deep sources. Finally, we hypothesise how a reduction in sea level may have altered the distribution of shelf sediment iron sources in the Southern Ocean and increased export production over the Sub-Antarctic Zone during glacial intervals

The Ursinus Weekly, May 4, 1964

WSGA revises constitution: Women to ratify provisions May 13 • UC wins award for alumni support • Greeks greet the sun with party weekend: Lee Vincent, King Twig, Little Anthony and Earl-J break the bleak week • Spring Festival features weekend of activities: Bye, bye Birdie Saturday • Mr. Pennypacker staged by Curtain Club • Band concert • Meistersingers repeat Spring concert for UC • WAA election and activities • UC students hear final concert • Editorial: Our faculty • Live cheaply and die rich • Fifty years ago • Letters to the editor • Dickinson and Johns Hopkins bow to UC trackmen 89-62-11: Rogart, Cooper, Dunn and Gladstone smash school, meet and field records • Rain doesn\u27t dampen spirits: UC swamps West Chester 15-3; Regester pitches 2nd victory in triumph over arch-rival • UC nine drops two close ones to F&M 4-3 and to Wilkes 3-2 • Dr. Howard named tennis advisor • MACs and PMC pose problems in track • Faculty members receive national science grants: Snyder to teach, Schultz to study in Summer schools • Greek gleaningshttps://digitalcommons.ursinus.edu/weekly/1273/thumbnail.jp

Tracer Survey in the Cape Verde Region Traceraufnahme in der Kapverdenregion Cruise No. 10, Leg 1 October 31 – December 06, 2008 Ponta Delgada (Portugal) – Mindelo (Cape Verde Islands)

The research cruise MSM10/1 was extremely successful. All programs were able to collect high quality data and the anticipated goals of the expedition were fully met. We have been able to carry out the first comprehensive survey of a tracer release in the Guinea Upwelling region (GUTRE) roughly seven month after the tracer was released at 8°N 23°W in April 2008. We have estimated that a total of 40% of the tracer was found during this cruise. While the horizontal spreading and mixing was larger than anticipated, the vertical extent of the tracer found was small. The low vertical tracer spreading rate estimates are supported by the micro structure profile data. The extensive survey of the upper 1000m of the oxygen minimum zone (OMZ) allowed comparing our sections with several previous surveys. We found that the lowest oxygen values in the core of the OMZ have dropped at record low values below 40 μmol/kg. The preliminary findings from the trace metal work focused on Fe ligand measurements shows a slight higher excess ligand concentration in the surface (50m) for three stations. The two other stations show a slight decrease at this depth. A large number of biochemical samples were taken and were analyzed in Kiel for DNA and RNA diversity. The tracer release experiment provided an ideal environment for repeated biochemical sampling in the same water mass

Library Publishing Research Agenda

This publication is an exploration of areas in which research is needed to support practice in the field of library publishing. The Research Agenda offers exploratory overviews of six topics (assessment, labor, accessibility, non-traditional research outputs, peer review, and partnerships), each of which includes a summary, potential research questions, and a list of relevant resources. This publication will be of interest to anyone conducting or interested in conducting research in the field. The Research Agenda was authored by LPC’s Research Committee with input from the LPC community. HTML versio

Diagnóstico de acidentes de trabalho com tratores agrícolas no Estado do Rio Grande do Sul, Brasil

The increasingly expansion of agricultural mechanization has resulted in the generation of a sector unprepared for the prevention of accidents at work, especially those that occur with agricultural tractors. As a result, news related to work accidents involving tractor operators in rural areas are seen frequently in the media, although their official quantification is difficult due to the underreporting of these accidents. Therefore, the aim of this study was to develop a diagnosis of work accidents with agricultural tractors in the state of Rio Grande do Sul, based on judicial cases, in order to ascertain the accidents causes, the attribution of responsibilities and the magnitude of consequences represented by the material and personal damages resulting from these cases. Through the deductive-systematic-analytical method and descriptive statistics, 60 cases of work accidents were analyzed, in the period between 2000 and 2018, which generated legal demands. It was found that 96.8% of accidents could have been avoided through prevention, removing the act and the unsafe condition in the activities. In 62% of cases, the unsafe act was the cause of accidents, and 14% resulted from the combination of the unsafe act and the unsafe condition. As for liability for the occurrence of the accident, the employer was directly or indirectly responsible in 59% of the cases, mainly for non-compliance with the rules of work safety, especially the standards NR 12 and NR 31. The operator's death occurred in 45% of the accidents analyzed, due to the overturning or fall over of the agricultural tractor. Thus, the analysis of these accidents showed that in none of them the generating event is related to the machine, but rather to human error. Moreover, only the change in the attitude of employers and employees can improve this scenario.A rápida expansão da mecanização agrícola resultou na geração de um setor despreparado para a prevenção dos acidentes de trabalho, em especial aos que ocorrem com os tratores agrícolas. Com isso, são frequentes as notícias vinculadas nos meios de comunicação sobre acidentes de trabalho envolvendo operadores de tratores no meio rural, ainda que sua quantificação oficial seja difícil, devido à subnotificação desses acidentes. Nesse sentido, o objetivo deste estudo foi realizar um diagnóstico sobre os acidentes de trabalho com tratores agrícolas no estado do Rio Grande do Sul, com base em casos judiciais, a fim de apurar as causas dos acidentes, a atribuição de responsabilidades e a magnitude das consequências representadas pelos danos materiais e pessoais decorrentes desses casos. Através do método dedutivo-sistemático-analítico e da estatística descritiva, foram analisados 60 casos de acidentes de trabalho, no período de 2000 a 2018 e que geraram demandas judiciais. Constatou-se que 96,8% dos acidentes poderiam ter sido evitados por meio da prevenção, afastando o ato e a condição insegura nas atividades. Em 62% dos casos o ato inseguro foi a causa dos acidentes, e 14% foram resultantes da combinação do ato inseguro e da condição insegura. Quanto à responsabilização pela ocorrência do acidente, o empregador foi o responsável direto ou indireto em 59% dos casos, principalmente pela inobservância das regras de segurança do trabalho, em especial no atendimento das Normas Regulamentadoras NR 12 e NR 31. O óbito do operador ocorreu em 45% dos acidentes pesquisados, decorrentes do capotamento ou tombamento do trator agrícola. Dessa forma, a análise destes acidentes demonstrou que, em nenhum deles o fato gerador está relacionado a máquina, mas sim a falha humana. Além disso, somente a mudança na postura dos empregadores e trabalhadores poderá resultar na melhoria deste cenário

Grand Design and Flocculent Spirals in the Spitzer Survey of Stellar Structure in Galaxies (S4G)

Spiral arm properties of 46 galaxies in the Spitzer Survey of Stellar Structure in Galaxies (S4G) were measured at 3.6mu, where extinction is small and the old stars dominate. The sample includes flocculent, multiple arm, and grand design types with a wide range of Hubble and bar types. We find that most optically flocculent galaxies are also flocculent in the mid-IR because of star formation uncorrelated with stellar density waves, whereas multiple arm and grand design galaxies have underlying stellar waves. Arm-interarm contrasts increase from flocculent to multiple arm to grand design galaxies and with later Hubble types. Structure can be traced further out in the disk than in previous surveys. Some spirals peak at mid-radius while others continuously rise or fall, depending on Hubble and bar type. We find evidence for regular and symmetric modulations of the arm strength in NGC 4321. Bars tend to be long, high amplitude, and flat-profiled in early type spirals, with arm contrasts that decrease with radius beyond the end of the bar, and they tend to be short, low amplitude, and exponential-profiled in late Hubble types, with arm contrasts that are constant or increase with radius. Longer bars tend to have larger amplitudes and stronger arms.Comment: 31 pages, 14 figures, ApJ in pres

Testing Biochemistry Revisited: How In Vivo Metabolism Can Be Understood from In Vitro Enzyme Kinetics

A decade ago, a team of biochemists including two of us, modeled yeast glycolysis and showed that one of the most studied biochemical pathways could not be quite understood in terms of the kinetic properties of the constituent enzymes as measured in cell extract. Moreover, when the same model was later applied to different experimental steady-state conditions, it often exhibited unrestrained metabolite accumulation

Ten new insights in climate science 2022

Non-technical summary We summarize what we assess as the past year's most important findings within climate change research: limits to adaptation, vulnerability hotspots, new threats coming from the climate–health nexus, climate (im)mobility and security, sustainable practices for land use and finance, losses and damages, inclusive societal climate decisions and ways to overcome structural barriers to accelerate mitigation and limit global warming to below 2°C. Technical summary We synthesize 10 topics within climate research where there have been significant advances or emerging scientific consensus since January 2021. The selection of these insights was based on input from an international open call with broad disciplinary scope. Findings concern: (1) new aspects of soft and hard limits to adaptation; (2) the emergence of regional vulnerability hotspots from climate impacts and human vulnerability; (3) new threats on the climate–health horizon – some involving plants and animals; (4) climate (im)mobility and the need for anticipatory action; (5) security and climate; (6) sustainable land management as a prerequisite to land-based solutions; (7) sustainable finance practices in the private sector and the need for political guidance; (8) the urgent planetary imperative for addressing losses and damages; (9) inclusive societal choices for climate-resilient development and (10) how to overcome barriers to accelerate mitigation and limit global warming to below 2°C. Social media summary Science has evidence on barriers to mitigation and how to overcome them to avoid limits to adaptation across multiple fields

Cell-Type Independent MYC Target Genes Reveal a Primordial Signature Involved in Biomass Accumulation

The functions of key oncogenic transcription factors independent of context have not been fully delineated despite our richer understanding of the genetic alterations in human cancers. The MYC oncogene, which produces the Myc transcription factor, is frequently altered in human cancer and is a major regulatory hub for many cancers. In this regard, we sought to unravel the primordial signature of Myc function by using high-throughput genomic approaches to identify the cell-type independent core Myc target gene signature. Using a model of human B lymphoma cells bearing inducible MYC, we identified a stringent set of direct Myc target genes via chromatin immunoprecipitation (ChIP), global nuclear run-on assay, and changes in mRNA levels. We also identified direct Myc targets in human embryonic stem cells (ESCs). We further document that a Myc core signature (MCS) set of target genes is shared in mouse and human ESCs as well as in four other human cancer cell types. Remarkably, the expression of the MCS correlates with MYC expression in a cell-type independent manner across 8,129 microarray samples, which include 312 cell and tissue types. Furthermore, the expression of the MCS is elevated in vivo in Eμ-Myc transgenic murine lymphoma cells as compared with premalignant or normal B lymphocytes. Expression of the MCS in human B cell lymphomas, acute leukemia, lung cancers or Ewing sarcomas has the highest correlation with MYC expression. Annotation of this gene signature reveals Myc's primordial function in RNA processing, ribosome biogenesis and biomass accumulation as its key roles in cancer and stem cells

The Arctic freshwater system : changes and impacts

Author Posting. © American Geophysical Union, 2007. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 112 (2007): G04S54, doi:10.1029/2006JG000353.Dramatic changes have been observed in the Arctic over the last century. Many of these involve the storage and cycling of fresh water. On land, precipitation and river discharge, lake abundance and size, glacier area and volume, soil moisture, and a variety of permafrost characteristics have changed. In the ocean, sea ice thickness and areal coverage have decreased and water mass circulation patterns have shifted, changing freshwater pathways and sea ice cover dynamics. Precipitation onto the ocean surface has also changed. Such changes are expected to continue, and perhaps accelerate, in the coming century, enhanced by complex feedbacks between the oceanic, atmospheric, and terrestrial freshwater systems. Change to the arctic freshwater system heralds changes for our global physical and ecological environment as well as human activities in the Arctic. In this paper we review observed changes in the arctic freshwater system over the last century in terrestrial, atmospheric, and oceanic systems.The authors gratefully acknowledge the National Science Foundation (NSF) for funding this synthesis work. This paper is principally the work of authors funded under the NSF-funded Freshwater Integration (FWI) study