505 research outputs found

    Brief communication:Conventional assumptions involving the speed of radar waves in snow introduce systematic underestimates to sea ice thickness and seasonal growth rate estimates

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    Pan-Arctic sea ice thickness has been monitored over recent decades by satellite radar altimeters such as CryoSat-2, which emits Ku-band radar waves that are assumed in publicly available sea ice thickness products to penetrate overlying snow and scatter from the ice–snow interface. Here we examine two expressions for the time delay caused by slower radar wave propagation through the snow layer and related assumptions concerning the time evolution of overlying snow density. Two conventional treatments introduce systematic underestimates of up to 15 cm into ice thickness estimates and up to 10 cm into thermodynamic growth rate estimates over multi-year ice in winter. Correcting these biases would impact a wide variety of model projections, calibrations, validations and reanalyses

    ASOSIASI ECHINODERMATA DENGAN KOMUNITAS PADANG LAMUN DI PERAIRAN DESA MANGON KECAMATAN SANANA KABUPATEN KEPULAUAN SULA

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    The purpose of this study was to determine the association between the phylum Echinodermataand the seagrass community in the waters of Mangon Village. This research was conducted in thewaters of Mangon Village, Sanana District, Sula Islands Regency in October 2022. The researchmethod used was the quadratic transect method. This method consists of 2 research stations which areabout 500m apart. The transect line is drawn straight from the beach to the sea for 100m then aquadratic plot is placed in a zig-zag manner to the left and right of the transect line. There were 10 plotsthat were observed and spaced 10m each and 3 repetitions were carried out with a distance of 50m pertransect. From this method the results obtained in the waters of Mangon Village showed that at stationone, the species found at two stations in Mangon Village waters were 7 species of Echinodermata and6 species of seagrass. Based on the person product moment correlation value, there is a correlation inthe form of a positive association between seagrasses and echinoderms at the study site. Theenvironmental parameters owned by the waters of Mangon Village, Sula Islands Regency, namely,temperature has a range of 24-28˚C, salinity has a range of 28 – 340/00, and pH has a range of 7,08-8,08. The substrate obtained is sand and sand mixed with coral fragments.Keywords: Association of Echinodermata with Seagrass Community, Mangon Village Waters ABSTRAKTujuan penelitian ini adalah untuk mengetahui asosiasi antara filum Echinodermata denganKomunitas padang lamun di perairan Desa Mangon. Penelitian ini dilakukan di perairan Desa MangonKecamatan Sanana Kabupaten Kepulauan Sula pada bulan Oktober 2022. Metode penelitian yangdigunakan adalah metode transek kuadrat, Dalam metode ini terdiri dari 2 stasiun penelitian yangmemiliki jarak sekitar 500m. Garis transek ditarik lurus dari pantai menuju laut sepanjang 100mkemudian diletakkan plot kuadrat secara zig-zag disamping kiri-kanan pada garis transek. Terdapat 10buah plot yang diamati dan diberi jarak masing-masing 10m dan dilakukan sebanyak 3 kalipengulangan dengan jarak 50m per transek. Dari Metode tersbut hasil yang didapatkan di perairanDesa Mangon menunjukan bahwa pada stasiun satu, Spesies yang ditemukan pada dua stasiun diPerairan Desa Mangon adalah 7 spesies Echinodermata dan 6 spesies lamun. Berdasarkan nilaikorelasi person product moment, terdapat korelasi dalam bentuk asosisasi positif antara lamun danEchinodermata di lokasi penelitian. Parameter lingkungan yang dimiliki oleh perairan Desa MangonKabupaten Kepulauan Sula yaitu, suhu memiliki kisaran 24-28˚C, salinitas memiliki kisaran 28 - 340/00,dan pH memiliki kisaran 7,08-8,08. Substrat yang di dapat yaitu pasir dan pasir bercampur pecahankarang. Kata Kunci: Asosiasi Echinodermata, Komunitas Padang Lamun, Perariran Desa Mango

    Monte-Carlo sampling of energy-constrained quantum superpositions in high-dimensional Hilbert spaces

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    Recent studies into the properties of quantum statistical ensembles in high-dimensional Hilbert spaces have encountered difficulties associated with the Monte-Carlo sampling of quantum superpositions constrained by the energy expectation value. A straightforward Monte-Carlo routine would enclose the energy constrained manifold within a larger manifold, which is easy to sample, for example, a hypercube. The efficiency of such a sampling routine decreases exponentially with the increase of the dimension of the Hilbert space, because the volume of the enclosing manifold becomes exponentially larger than the volume of the manifold of interest. The present paper explores the ways to optimise the above routine by varying the shapes of the manifolds enclosing the energy-constrained manifold. The resulting improvement in the sampling efficiency is about a factor of five for a 14-dimensional Hilbert space. The advantage of the above algorithm is that it does not compromise on the rigorous statistical nature of the sampling outcome and hence can be used to test other more sophisticated Monte-Carlo routines. The present attempts to optimise the enclosing manifolds also bring insights into the geometrical properties of the energy constrained manifold itself.Comment: 9 pages, 7 figures, accepted for publication in European Physical Journal

    Assessing pesticide pollution of groundwater: current knowledge and remaining gaps

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    This paper summarises recent research on pesticides in groundwater in both temperate and tropical regions. Results of field, laboratory and modelling studies highlight the factors which determine the fate and behaviour of pesticides in groundwater systems. These include transport pathways from the soil to the water table and thence to supply sources, and the processes such as adsorption and degradation which can help to attenuate pesticide movement and reduce concentrations. Studies of degradation show that most compounds are likely to be much more persistent in aquifers than in soils, but below the water table the long travel times and potential for dilution may greatly reduce concentrations. The greatest risks are likely to occur in fractured aquifers with their potential for much more rapid flow. Important uncertainties and gaps in knowledge remain. Laboratory studies of degradation present difficulties of extrapolation to field conditions and provide evidence of wide variations in half-lives spatially and with time; making the choice of values for transport modelling problematic. Further work is required to improve understanding of such variations. Studies can also indicate that different degradation pathways can occur and different pesticide metabolites produced, depending onenvironmental conditions. The occurrence and behaviour of metabolites in groundwater systems is also poorly known

    How can gender considerations be better integrated into animal health emergency preparedness and response?

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    Global and national authorities have not historically approached animal health emergencies through a gendered lens. Yet these events almost certainly have gendered dimensions, such as differential engagement of women or men depending on their culturally accepted or assigned roles for animal care; risk of exposure to zoonoses; and access to emergency resources during response and recovery. Despite the role that gender seems to play with respect to animal health emergencies, little research has been conducted to better understand such dynamics, and little policy has been promulgated to address it in a way that optimizes response while ensuring equitable outcomes. This piece summarizes 3 key themes that emerged from a panel discussion on gender and animal health emergencies at the World Organisation for Animal Health Global Conference on Emergency Management in April 2023. These themes were differential gendered exposure to pathogens; a lack of equitable gender representation in animal health decision-making; and enhancement of pathways for recognizing gender in national and international actions in preparing for, detecting, and responding to animal health emergencies. Beyond increasing opportunities for women to engage in leadership, the animal health and veterinary communities will benefit from connecting practitioners with gender experts to develop more integrative approaches to emergency preparedness and management. Animal health professionals should also advocate for further research to elucidate gender-specific dynamics in human populations in the context of animal emergencies and the promulgation of evidence-based policies. Such transformative efforts will lead to better outcomes for all people who depend on and provide care for animals

    Prospects for Studies of Stellar Evolution and Stellar Death in the JWST Era

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    I review the prospects for studies of the advanced evolutionary stages of low-, intermediate- and high-mass stars by the JWST and concurrent facilities, with particular emphasis on how they may help elucidate the dominant contributors to the interstellar dust component of galaxies. Observations extending from the mid-infrared to the submillimeter can help quantify the heavy element and dust species inputs to galaxies from AGB stars. JWST's MIRI mid-infrared instrument will be so sensitive that observations of the dust emission from individual intergalactic AGB stars and planetary nebulae in the Virgo Cluster will be feasible. The Herschel Space Observatory will enable the last largely unexplored spectral region, the far-IR to the submillimeter, to be surveyed for new lines and dust features, while SOFIA will cover the wavelength gap between JWST and Herschel, a spectral region containing important fine structure lines, together with key water-ice and crystalline silicate bands. Spitzer has significantly increased the number of Type II supernovae that have been surveyed for early-epoch dust formation but reliable quantification of the dust contributions from massive star supernovae of Type II, Type Ib and Type Ic to low- and high-redshift galaxies should come from JWST MIRI observations, which will be able to probe a volume over 1000 times larger than Spitzer.Comment: 24 pages, 19 figures. To appear in `Astrophysics in the Next Decade: JWST and Concurrent Facilities' (JWST Conference Proceedings), edited by H. A. Thronson, M. Stiavelli and A. G. G. M. Tielens; Springer Series: Astrophysics and Space Science Proceeding

    Size Doesn't Matter: Towards a More Inclusive Philosophy of Biology

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    notes: As the primary author, O’Malley drafted the paper, and gathered and analysed data (scientific papers and talks). Conceptual analysis was conducted by both authors.publication-status: Publishedtypes: ArticlePhilosophers of biology, along with everyone else, generally perceive life to fall into two broad categories, the microbes and macrobes, and then pay most of their attention to the latter. ‘Macrobe’ is the word we propose for larger life forms, and we use it as part of an argument for microbial equality. We suggest that taking more notice of microbes – the dominant life form on the planet, both now and throughout evolutionary history – will transform some of the philosophy of biology’s standard ideas on ontology, evolution, taxonomy and biodiversity. We set out a number of recent developments in microbiology – including biofilm formation, chemotaxis, quorum sensing and gene transfer – that highlight microbial capacities for cooperation and communication and break down conventional thinking that microbes are solely or primarily single-celled organisms. These insights also bring new perspectives to the levels of selection debate, as well as to discussions of the evolution and nature of multicellularity, and to neo-Darwinian understandings of evolutionary mechanisms. We show how these revisions lead to further complications for microbial classification and the philosophies of systematics and biodiversity. Incorporating microbial insights into the philosophy of biology will challenge many of its assumptions, but also give greater scope and depth to its investigations

    'Disc-jet' coupling in black hole X-ray binaries and active galactic nuclei

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    In this chapter I will review the status of our phenomenological understanding of the relation between accretion and outflows in accreting black hole systems. This understanding arises primarily from observing the relation between X-ray and longer wavelength (infrared, radio) emission. The view is necessarily a biased one, beginning with observations of X-ray binary systems, and attempting to see if they match with the general observational properties of active galactic nuclei.Comment: 28 pages, 15 figures, To appear in Belloni, T. (ed.): The Jet Paradigm - From Microquasars to Quasars, Lect. Notes Phys. 794 (2009
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