916 research outputs found
Preferencias académicas de los estudiantes de la Carrera de Derecho y su vinculación con los Objetivos de Desarrollo Sostenible (ODS) a través del estudio de sentencia
No full textN/
Diseño de un sistema de costos para la ceba de ganado bovino razas doble propósito, en el municipio de Arauca.
No full textLa contabilidad de costos es una de las herramientas más importantes para determinar la rentabilidad en un negocio o empresa de cualquier actividad económica; dentro de sus múltiples aplicaciones, es utilizada en el cálculo del precio de los productos, especialmente cuando la producción es de tipo industrial.
La actividad ganadera es uno de los pilares económicos más importantes dentro de la economía del municipio de Arauca, después de la explotación de petróleo; en los últimos años los ganaderos han implementado diversas técnicas y métodos que permiten aumentar y mejorar la producción de ganado, generando una mayor ganancia en la venta de cada animal. En el mismo sentido, las inversiones en la producción también se incrementaron en comparación con la producción de ganado extensiva tradicional, que aun predomina en la mayoría de fincas ganaderas del Departamento.Resumen.
La producción ganadera en el Municipio de Arauca ha sido una de las actividades económicas tradicionales de la región, la cual en los últimos años ha experimento un avance en el modo de producción mediante la implementación de tecnificación del campo, introduciendo mejoramientos en las razas de los animales, cambios en la alimentación y nutrición de los mismos, y modificando aspectos como los modos de producción de una ganadería extensiva a ganadería intensiva, con el fin de aumentar las cantidades producidas así como maximizar rentabilidades a un corto plazo.
Sin embargo la producción de ceba de ganado en cuanto al proceso de costeo de la misma, se realiza de una forma rudimentaria o empírica, lo cual no permite al ganadero obtener de forma clara las utilidades que pueda llegar a tener o si es el caso la perdida generada a esto se le suma que no existe una herramienta sistematizada que les permita a los productores realizar este cálculo de una manera exacta, precisa y que refleje la realidad en la utilidad obtenida en el ejercicio.
Para ello es necesario desarrollar un sistema de costeo que nos permita identificar los procesos en el desarrollo de la ceba de ganado en el municipio de Arauca, así como también los elementos del costo, como lo son las materias primas, mano de obra y costos indirectos de fabricación CIF; teniendo en cuenta la información obtenida mediante la investigación realizada para el desarrollo de este proyecto se determinó implementar un sistema de costos por procesos el cual definiremos en el desarrollo de este proyecto, el cual se ajusta a las necesidades, condiciones y procesos que conlleva esta actividad.Tabla De Contenido. --
Lista de tablas. --
Ilustraciones. --
Lista de anexos. --
Resumen. --
Abstrac. --
Introducción. --
1. Planteamiento del problema. --
Formulación del problema. --
2 Justificación. --
3 Objetivos. --
Objetivo General. --
Objetivos Específicos. --
4 Marco De Referencia. --
Marco Contextual. --
Marco Legal. --
4.2.1 Ley 89 De 1993. --
4.2.2 Ley 395 De 1991. --
4.2.3 Ley 101 De 1993. --
4.2.4 Decreto 3044 De 1997. --
4.2.5 Decreto 1500 De 2007. --
4.2.6 Resolución 3333 De 2010. --
4.2.7 Resolución 1779 De 1998. --
4.2.8 Resolución 1332 De 2013. --
4.2.9 Decreto 2270 De 2012. --
4.2.10 Decreto 3149 De 2006. --
4.2.11 Decreto 414 De 2007. --
4.2.12 Resolución 185 De 2007. --
4.2.13 Decreto 3050 De 1997. --
4.2.14 Decreto 1794 De 1993. --
Marco Conceptual. --
4.3.1 Definición de costo. --
4.3.2 Materiales o Materia Prima. --
4.3.3 Mano de obra. --
4.3.4 Costos Indirectos de Fabricación. --
4.3.5 Contabilidad de costos. --
4.3.6 Sistema De Costos. --
4.3.7 Clases de sistema de costos. --
4.3.8 Sistema de costos por órdenes de trabajo. --
4.3.9 Sistema de costos por procesos. --
4.3.10 Ganadería y elementos en la producción ganadera. --
4.3.11 Ganadero. --
4.3.12 Finca. --
4.3.13 Corral. --
4.3.14 Potreros. --
4.3.15 Pastos, gramíneas y forrajes. --
4.3.16 Ganado bovino: tipos. --
4.3.17 Enfermedades en la producción. --
5. Limitaciones y alcances. --
Limitaciones. --
Alcances. --
6. Metodología. --
Naturaleza de la investigación. --
Método. --
Corrientes metodológicas. --
Fuentes y técnicas de recolección de la información. --
7. Descripción de actividades y desarrollo según objetivos propuestos. --
Presupuesto. --
Cronograma. --
Objetivo Nº 1. --
7.1.1. Ceba de ganado. --
7.1.2. Sistemas de explotación ganadera. --
7.1.3. Extensivos Tradicional. --
7.1.4. Extensivos Mejorado. --
7.1.5. Pastoreo intensivo suplementado. --
7.1.6. Nutrición animal. --
7.1.7. Ración --
7.1.8. Forrajes. --
7.1.9. Pastos. --
7.1.10. Pasto aguja - brachiaria humidicola. --
7.1.11. Pasto Llanero - Brachiaria Dictyoneura. --
7.1.12. Pasto Ruzzi - Brachiaria Ruziziensis. --
7.1.13. Pasto Taner - Brachiaria Arrecta. --
7.1.14. Cynodon nlemfluensis. --
7.1.15. Ensilaje. --
7.1.16. Agua. --
7.1.17. Suplementos minerales. --
7.1.18. Vitaminas. --
7.1.19. Instalaciones. --
7.1.20. Sombreadores. --
7.1.21. Establos. --
7.1.22. Corrales. --
7.1.23. Mangas. --
7.1.24. Embarcadero. --
7.1.25. Maquinaria y equipos. --
7.1.26. Tractor. --
7.1.27. Maquinas Henificadoras. --
7.1.28. Comederos y Bebederos. --
7.1.29. Proceso de ceba. --
Objetivo Nº 2. --
7.4.1 Muestra. --
7.4.2 Resultados y análisis de las entrevistas. --
7.4.3 Elemento del costo – Procesos producción ceba. --
Objetivo Nº 3. --
7.5.1 Manual sicoprogan. --
8 Conclusiones. --
9 Bibliografía. --
10 Anexos. --
Registro Fotográfico. --
Encuestas realizadas. [email protected]
Macroeconomic constraints for medium term growth and distribution : a model for Chile
Get PDFThe recovery of the Chilean economy since the mid 1980s, has certainly been successful in macroeconomic terms. In fact, the restoration of growth and the correction of external imbalances after the severe economic crises of 1982 -83 has taken place in a macroeconomic environment of moderate inflation, without major fiscal imbalances, exports have expanded significantly and foreign debt burden indicators have improved. However, distributive and poverty related indicators point to pending problems. The major challenge, therefore, is to maintain sustainable rates of economic growth, address the social issues of poverty reduction and improve income distribution patterns, while preserving macroeconomic and financial stability. The paper is organized as follows : Section I is an introduction. Section II presents a formal macroeconomic model that identifies major constraints ( external, savings and fiscal ) that shape the scope for growth. In Section III the model is numerically calibrated with parameters of the economy and three policy exercises are explored : i) an increase in public spending; ii) a reduction of interest payments of 3% of potential GDP; and iii) a reduction of the markup rate of 4%. Section IV reviews various policy excercises and the conclusions are summarized in Section V.Achieving Shared Growth,Economic Theory&Research,Environmental Economics&Policies,Economic Stabilization,Banks&Banking Reform
Perspectives of the River Plate around the time of Rosas : an analysis based upon the personal correspondence, private memoirs and published accounts of British settlers, as well as works by creole authors
No full textThis thesis draws inspiration from the emergence of cultural studies as an academic
pursuit, in addition to the current renewal of interest in the relationship between
literary works and their socio-cultural milieux, to bring together an assortment of
textual traces pertaining to the River Plate around the era of Juan Manuel de Rosas,
governor of Buenos Aires and de facto dictator of Argentina for most of the period
1829-1852. The main texts analysed range from private documents relating to two
Scottish settler families, through accounts published by British citizens with first-hand
knowledge of the region (Un inglés, Cinco años en Buenos Aires and
Beaumont, Travels in Buenos Ayres and the Adjacent Provinces), to three influential
pieces of early Argentinian literature (Echeverria's El matadero, Mármol's Amalia
and Sarmiento's Facundo). One justification of this apparently eclectic approach lies
in the prominence accorded to the incomer in the thought of liberal Platine
intellectuals, a concern evinced in their literary production.
The methodology involves examining the representation of certain
fundamental topics across this range of written artefacts, observing frequent points of
thematic convergence amongst the various texts. In this fashion, I construct an image
of the River Plate region around the Rosas period, whilst also appraising the degree
to which early British settlers matched the idealized notion of the immigrant present
in liberal creole writings.
The study is divided into four main chapters, supplemented by an
introduction, conclusion and appendix. The first chapter summarizes the historical
context of the young Platine republics; the second deals with the themes of society,
community and family, the third focuses upon religion; the fourth considers
perspectives of politics, dictatorship and civil war. The appendix consists of an
unpublished settler autobiography, a remarkable account of the tribulations faced on
a daily basis in the developing Argentina
A multi level model of school effectiveness in a developing country
Get PDFWhat makes one school more effective than another - particularly which inputs and management practices most efficiently enhance student achievement - has become the center of lively debate in the literature. Which method to use to compare school effects particularly concerns analysts. The model developed by the authors is able to explain most variance between schools but significantly less within schools. Only one variable slope is observed: the relationship between educational aspirations and achievement. The authors apply multi level techniques to longitudinal data recently collected by the International Association for the Evaluation of Educational Achievement in Thailand. One question they try to answer is : how do estimates obtained from the new multi level techniques compare with those obtained from ordinary regression models?Teaching and Learning,Gender and Education,Health Monitoring&Evaluation,Statistical&Mathematical Sciences,Educational Sciences
Macroeconomics of public sector deficits : the case of Zimbabwe
Get PDFZimbabwe has the uncommon combination of a high public deficit, a balanced current account, low inflation, and low levels of investment and growth. Despite a surplus in the current account, the nonfinancial public sector has run deficits exceeding 10 percent of GDP since 1981. Inflation is low but interest rates are rising because of partial financial liberalization and rising domestic public debt stocks. Heavy public spending crowded out private consumption and investment in the 1980s. The private saving rate is a staggering 20 percent of GDP, which finances all of Zimbabwe's investment. The fiscal adjustment begun in 1987 helped stabilize the public debt and improved recovery of investment. But more fiscal adjustment is needed to improve macroeconomic and financial stability and growth prospects. Public deficits must be reduced to ensure a sustainable path for public debt. High deficits are crowding out both private consumption and private investment. The public sector must be adjusted and foreign trade must be reformed to improve capital formation - a prerequisite for improving growth prospects in Zimbabwe.Environmental Economics&Policies,Economic Theory&Research,Banks&Banking Reform,Public Sector Economics&Finance,Economic Stabilization
A scaling-relation for disc galaxies: circular-velocity gradient versus central surface brightness
Get PDFFor disc galaxies, a close relation exists between the distribution of light and the
shape of the rotation curve. We quantify this relation by measuring the inner circular-
velocity gradient dRV (0) for spiral and irregular galaxies with high-quality rotation
curves. We find that dRV (0) correlates with the central surface brightness μ0 over
more than two orders of magnitude in dRV (0) and four orders of magnitudes in μ0.
This is a scaling-relation for disc galaxies. It shows that the central stellar density of a
galaxy closely relates to the inner shape of the potential well, also for low-luminosity
and low-surface-brightness galaxies that are expected to be dominated by dark matter.
Key words: dark matter – galaxies: kinematics and dynamics – galaxies: structure
DNA Glycosylases Involved in Base Excision Repair May Be Associated with Cancer Risk in BRCA1 and BRCA2 Mutation Carriers.
Get PDFSingle Nucleotide Polymorphisms (SNPs) in genes involved in the DNA Base Excision Repair (BER) pathway could be
associated with cancer risk in carriers of mutations in the high-penetrance susceptibility genes BRCA1 and BRCA2, given the relation of synthetic lethality that exists between one of the components of the BER pathway, PARP1 (poly ADP ribose
polymerase), and both BRCA1 and BRCA2. In the present study, we have performed a comprehensive analysis of 18 genes involved in BER using a tagging SNP approach in a large series of BRCA1 and BRCA2 mutation carriers. 144 SNPs were analyzed in a two stage study involving 23,463 carriers from the CIMBA consortium (the Consortium of Investigators of Modifiers of BRCA1 and BRCA2). Eleven SNPs showed evidence of association with breast and/or ovarian cancer at p,0.05 in the combined analysis. Four of the five genes for which strongest evidence of association was observed were DNA glycosylases. The strongest evidence was for rs1466785 in the NEIL2 (endonuclease VIII-like 2) gene (HR: 1.09, 95% CI (1.03– 1.16), p = 2.761023) for association with breast cancer risk in BRCA2 mutation carriers, and rs2304277 in the OGG1 (8-guanine DNA glycosylase) gene, with ovarian cancer risk in BRCA1 mutation carriers (HR: 1.12 95%CI: 1.03–1.21,
p = 4.861023). DNA glycosylases involved in the first steps of the BER pathway may be associated with cancer risk in BRCA1/ 2 mutation carriers and should be more comprehensively studied
Identification of the Top TESS Objects of Interest for Atmospheric Characterization of Transiting Exoplanets with JWST
No full textHord, Benjamin J. et al.--Full list of authors: Hord, Benjamin J.; Kempton, Eliza M-R; Evans-Soma, Thomas M.; Latham, David W.; Ciardi, David R.; Dragomir, Diana; Colon, Knicole D.; Ross, Gabrielle; Vanderburg, Andrew; De Beurs, Zoe L.; Collins, Karen A.; Watkins, Cristilyn N.; Bean, Jacob; Cowan, Nicolas B.; Daylan, Tansu; Ih, Jegug; Morley, Caroline V.; Barkaoui, Khalid; Baker, David; Behmard, Aida; Batalha, Natalie M.; Benkhaldoun, Zouhair; Belinski, Alexander; Bernacki, Krzysztof; Benni, Paul; Binnenfeld, Avraham; Bieryla, Allyson; Bouchy, Franccois; Bosch-Cabot, Pau; Brahm, Rafael; Bozza, Valerio; Chontos, Ashley; Clark, Catherine A.; Buchhave, Lars A.; Calkins, Michael; Collins, Kevin I.; Conti, Dennis M.; Cloutier, Ryan; Cointepas, Marion; de Leon, Jerome P.; Dransfield, Georgina; Crossfield, Ian J. M.; Dai, Fei; Esquerdo, Gilbert; Evans, Phil; Dressing, Courtney; Dustor, Adam; Frasca, Antonio; Fores-Toribio, Raquel; Fiolka, Jerzy; Fajardo-Acosta, Sergio B.; Gan, Tianjun; Furlan, Elise; Fulton, Benjamin; Fukui, Akihiko; Gilbert, Emily A.; Giacalone, Steven; Ghachoui, Mourad; Gandolfi, Davide; Horta, Ferran Grau; Gonzales, Erica; Girardin, Eric; Gillon, Michael; Hellier, Coel; Helm, Ian; Helminiak, Krzysztof G.; Henning, Thomas; Gregorio, Joao; Greklek-McKeon, Michael; Guerra, Pere; Hartman, J. D.; Huber, Daniel; Isopi, Giovanni; Jehin, Emmanuel; Jenkins, Jon M.; Hill, Michelle L.; Horne, Keith; Howard, Andrew W.; Howell, Steve B.; Krushinsky, Vadim; Kielkopf, John F.; Lee, Elena; Lasota, Slawomir; Johnson, Marshall C.; Jensen, Eric L. N.; Kane, Stephen R.; Jordan, Andres; Mann, Christopher R.; Mallia, Franco; Maslennikova, Nataliia; Marino, Giuseppi; Livingston, John H.; Lewin, Pablo; Lund, Michael B.; Lubin, Jack; Michaels, Edward J.; Mocnik, Teo; Mazeh, Tsevi; McLeod, Kim K.; Matthews, Elisabeth; Mayo, Andrew W.; Massey, Bob; Matson, Rachel; Osborn, Hugh; Palle, Enric; Natarajan, Krupa; Nielsen, Louise Dyregaard; Munoz, Jose A.; Narita, Norio; Mori, Mayuko; Mraz, Georgia; Radford, Don J.; Quinn, Samuel N.; Pozuelos, Francisco J.; Popowicz, Adam; Polanski, Alex S.; Plavchan, Peter; Papini, Riccardo; Panahi, Aviad; Schanche, Nicole; Rubenzahl, Ryan A.; Rosenthal, Lee J.; Rodriguez, Joseph E.; Robertson, Paul; Rice, Malena; Relles, Howard M.; Reed, Phillip A.; Timmermans, Mathilde; Tan, Thiam-Guan; Van Zandt, Judah; Ting, Eric B.; Waite, Ian; Vignes, J. P.; Weiss, Lauren M.; Watanabe, Noriharu; Schwarz, Richard P.; Schlieder, Joshua; Shporer, Avi; Sefako, Ramotholo; Srdoc, Gregor; Sozzetti, Alessandro; Tarasenkov, Alexander; Stockdale, Chris; Wittrock, Justin; Zhou, George; Ziegler, Carl; Zucker, ShayJWST has ushered in an era of unprecedented ability to characterize exoplanetary atmospheres. While there are over 5000 confirmed planets, more than 4000 Transiting Exoplanet Survey Satellite (TESS) planet candidates are still unconfirmed and many of the best planets for atmospheric characterization may remain to be identified. We present a sample of TESS planets and planet candidates that we identify as "best-in-class" for transmission and emission spectroscopy with JWST. These targets are sorted into bins across equilibrium temperature Teq and planetary radius Rp and are ranked by a transmission and an emission spectroscopy metric (TSM and ESM, respectively) within each bin. We perform cuts for expected signal size and stellar brightness to remove suboptimal targets for JWST. Of the 194 targets in the resulting sample, 103 are unconfirmed TESS planet candidates, also known as TESS Objects of Interest (TOIs). We perform vetting and statistical validation analyses on these 103 targets to determine which are likely planets and which are likely false positives, incorporating ground-based follow-up from the TESS Follow-up Observation Program to aid the vetting and validation process. We statistically validate 18 TOIs, marginally validate 31 TOIs to varying levels of confidence, deem 29 TOIs likely false positives, and leave the dispositions for four TOIs as inconclusive. Twenty-one of the 103 TOIs were confirmed independently over the course of our analysis. We intend for this work to serve as a community resource and motivate formal confirmation and mass measurements of each validated planet. We encourage more detailed analysis of individual targets by the community. © 2024. The Author(s). Published by the American Astronomical Society.Funding for the TESS mission is provided by NASA's Science Mission Directorate. This research has made use of the Exoplanet Follow-up Observation Program (ExoFOP) website (NExScI 2022), which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. This paper includes data collected by the TESS mission, which are publicly available from the Mikulski Archive for Space Telescopes (MAST) and produced by the Science Processing Operations Center (SPOC) at NASA Ames Research Center. This research effort made use of systematic error-corrected (PDCSAP) photometry. Funding for the TESS mission is provided by NASA's Science Mission directorate. Resources supporting this work were provided by the NASA High-End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center for the production of the SPOC data products. Some/all of the data presented in this paper were obtained from the Mikulski Archive for Space Telescopes (MAST) at the Space Telescope Science Institute. The specific observations analyzed can be accessed via 10.17909/rd5r-m387. This work makes use of observations from the LCOGT network. Part of the LCOGT telescope time was granted by NOIRLab through the Mid-Scale Innovations Program (MSIP). MSIP is funded by NSF. This paper is based on observations made with the MuSCAT3 instrument, developed by the Astrobiology Center and under financial support by JSPS KAKENHI (grant No. JP18H05439) and JST PRESTO (grant No. JPMJPR1775), at Faulkes Telescope North on Maui, HI, operated by the Las Cumbres Observatory. This paper makes use of observations made with the MuSCAT2 instrument, developed by the Astrobiology Center, at TCS operated on the island of Tenerife by the IAC in the Spanish Observatorio del Teide. This paper makes use of data from the MEarth Project, which is a collaboration between Harvard University and the Smithsonian Astrophysical Observatory. The MEarth Project acknowledges funding from the David and Lucile Packard Fellowship for Science and Engineering, the National Science Foundation under grant Nos. AST-0807690, AST-1109468, AST-1616624 and AST-1004488 (Alan T. Waterman Award), the National Aeronautics and Space Administration under grant No. 80NSSC18K0476 issued through the XRP Program, and the John Templeton Foundation. C.M. would like to gratefully acknowledge the entire Dragonfly Telephoto Array team, and Bob Abraham in particular, for allowing their telescope bright time to be put to use observing exoplanets. B.J.H. acknowledges support from the Future Investigators in NASA Earth and Space Science and Technology (FINESST) program (grant No. 80NSSC20K1551) and support by NASA under grant No. 80GSFC21M0002. K.A.C. and C.N.W. acknowledge support from the TESS mission via subaward s3449 from MIT. This research made use of Lightkurve, a Python package for Kepler and TESS data analysis (Lightkurve Collaboration et al. 2018). Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. D.R.C. and C.A.C. acknowledge support from NASA through the XRP grant No. 18-2XRP18_2-0007. C.A.C. acknowledges that this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004). This research was carried out in part at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004). S.Z. and A.B. acknowledge support from the Israel Ministry of Science and Technology (grant No. 3-18143). The research leading to these results has received funding from the ARC grant for Concerted Research Actions, financed by the Wallonia-Brussels Federation. TRAPPIST is funded by the Belgian Fund for Scientific Research (Fond National de la Recherche Scientifique, FNRS) under the grant No. PDR T.0120.21. TRAPPIST-North is a project funded by the University of Liege (Belgium), in collaboration with Cadi Ayyad University of Marrakech (Morocco). M.G. is F.R.S.-FNRS Research Director and E.J. is F.R.S.-FNRS Senior Research Associate. The postdoctoral fellowship of K.B. is funded by F.R.S.-FNRS grant No. T.0109.20 and by the Francqui Foundation. H.P.O.'s contribution has been carried out within the framework of the NCCR PlanetS supported by the Swiss National Science Foundation under grant Nos. 51NF40_182901 and 51NF40_205606. F.J.P. acknowledges financial support from the grant No. CEX2021-001131-S funded by MCIN/AEI/ 10.13039/501100011033. A.J. acknowledges support from ANID—Millennium Science Initiative—ICN12_009 and from FONDECYT project 1210718. Z.L.D. acknowledges the MIT Presidential Fellowship and that this material is based upon work supported by the National Science Foundation Graduate Research Fellowship under grant No. 1745302. P.R. acknowledges support from the National Science Foundation grant No. 1952545. Some of the observations in this paper made use of the High-Resolution Imaging instruments 'Alopeke and Zorro, and were obtained under Gemini LLP Proposal Number GN/S-2021A-LP-105. 'Alopeke/Zorro were funded by the NASA Exoplanet Exploration Program and built at the NASA Ames Research Center by Steve B. Howell, Nic Scott, Elliott P. Horch, and Emmett Quigley. Alopeke/Zorro was mounted on the Gemini North/South 8 m telescopes of the international Gemini Observatory, a program of NSF's NOIRLab, which is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation, on behalf of the Gemini partnership: the National Science Foundation (United States), National Research Council (Canada), Agencia Nacional de Investigación y Desarrollo (Chile), Ministerio de Ciencia, Tecnología e Innovación (Argentina), Ministério da Ciência, Tecnologia, Inovações e Comunicações (Brazil), and Korea Astronomy and Space Science Institute (Republic of Korea). This work is partly supported by JSPS KAKENHI grant Nos. JP17H04574, JP18H05439, JP21K20376; JST CREST grant No. JPMJCR1761; and Astrobiology Center SATELLITE Research project AB022006. This article is based on observations made with the MuSCAT2 instrument, developed by ABC, at Telescopio Carlos Sánchez operated on the island of Tenerife by the IAC in the Spanish Observatorio del Teide. This paper is based on observations made with the MuSCAT3 instrument, developed by the Astrobiology Center and under financial supports by JSPS KAKENHI (grant No. JP18H05439) and JST PRESTO (grant No. JPMJPR1775), at Faulkes Telescope North on Maui, HI, operated by the Las Cumbres Observatory. This publication benefits from the support of the French Community of Belgium in the context of the FRIA Doctoral Grant awarded to M.T. D.D. acknowledges support from TESS Guest Investigator Program grant Nos. 80NSSC22K1353, 80NSSC22K0185, and 80NSSC23K0769. A.B. acknowledges the support of M.V. Lomonosov Moscow State University Program of Development. T.D. was supported in part by the McDonnell Center for the Space Sciences. V.K. acknowledges support from the youth scientific laboratory project, topic FEUZ-2020-0038.With funding from the Spanish government through the "Severo Ochoa Centre of Excellence" accreditation (CEX2021-001131-S).Peer reviewe
Physical and geochemical characterisation of canal sediments in the Black Country, West Midlands.
Get PDFA thesis submitted in fulfilment of the requirements of the University of
Wolverhampton for the award of the degree of Doctor of Philosophy (Ph.D.)Potentially harmful elements (PHEs) have been researched in a wide variety of disciplines, including pedology, chemistry, pollution science and medicine. Within the scientific community, emphasis has usually been placed on the toxic elements, such as cadmium, chromium, lead and arsenic, but rarely has there been consideration of interactions between PHEs, the sediment matrix and processes occurring in the sediments. Dredging of canals is needed for navigability purposes and consequently testing of dredged sediments (to assess whether sediments are hazardous) and landfilling can be costly for British Waterways facing constantly changing regulations and reduction in government grants. PHE mobility and availability in canal sediments can be affected by oxygen availability, pH and Redox. Remediation is thus becoming a priority for British Waterways to limit their operational costs. Zeolites, a type of remediation tool, have been widely studied in the past 30 years due to their attractive properties, such as molecular-sieving, high cation exchange capacities and their affinity for PHEs. The pilot study to investigate the efficiency of the clinoptilolite showed that there was a concentration difference between PHEs adsorbed by the clinoptilolite and the PHE concentration lost from the sediments from three sites in the West Midlands. Thorough characterisation of the sediments was needed to understand the speciation of the PHEs and the secondary processes occurring in the sediments. The different components of the sediments were analysed using various analytical methods, such as X-Ray Fluorescence spectroscopy (XRF), particle size and X-ray Diffraction (XRD) for the solid-inorganic phase, Ion Chromatography (IC) and Inductively Coupled Plasma-Optical Emissions Spectroscopy (ICP-OES) for the liquid phase (pore water), Gas Chromatography-Mass Spectrometry (GC-MS) and organic loss on ignition for the organic phase, pH and Redox for the electrochemistry of the sediments and Scanning Electron Microscope with Energy Dispersive X-Ray analysis (SEM-EDX) for microscopy and imaging. The British Geological Survey (BGS) sequential extraction method was used to investigate the different phases in the sediments. pH remained near neutral for all three sites and Redox remained anoxic. Organic contents for all three sites were around 30% and contained most of the polycyclic aromatic hydrocarbons considered hazardous. Pore water showed only high concentrations of sulphates but low concentrations of PHEs, suggesting PHEs were not mobile. Sequential extraction confirmed the other results showing that PHEs were mainly associated with stable phases, such as iron and manganese oxides or sulphides. The results have been taken into consideration to design a new remediation strategy to maximise efficiency of the zeolite
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