bluuebunny/crossref_metadata_2025 huggingface dataset:
Regular = planeado versus irregular = espontâneo
Authors: Pinto Sandra
Published: July 2020

Neste artigo analisa-se uma importante relação teórica nos estudos históricos sobre a forma urbana. Trata-se da relação que associa as formas urbanas regulares ao planeamento urbanístico e, pelo contrário, as formas urbanas irregulares à falta de planeamento urbanístico. Partindo da formulação inicial estabelecida nos textos inaugurais de história do urbanismo, procura-se verificar o impacto desta relação dicotómica na construção do conhecimento, para depois alcançar a transformação operada nas últimas décadas, que levou à sua refutação, utilizando para o efeito o contributo metodológico, teórico e conceptual de alguns estudos produzidos desde a segunda metade do século XX.
Interferências da forma urbana na dinâmica da temperatura intra-urbana
Authors: Chaves Drach Patricia Regina , Emmanuel Rohinton
Published: July 2020

As perspectivas de mudanças climáticas e suas possíveis consequências recomendam o desenvolvimento de estratégias para mitigar problemas relacionados ao sobreaquecimento urbano. O presente estudo tem como objetivo examinar a interferência da forma urbana, aferida pela Fracção de Céu Visível (Sky View Factor, SVF), sobre as variações na temperatura intra-urbana na cidade de Glasgow, Reino Unido, uma cidade de clima frio. 49 pontos de medição foram locados no centro da cidade e foram desenvolvidas 31 campanhas de coleta de dados, durante a primavera e o verão de 2013. Para cobrir uma grande área dentro de um tempo relativamente curto, foi utilizado o método de ‘transecto’ com rotas pré-determinadas, a pé e de bicicleta. O software ArcGIS foi utilizado para visualização dos resultados. Os resultados indicam que a variação da diferença da temperatura intra-urbana está fortemente relacionada à estabilidade atmosférica, sugerindo que esta tem realmente um importante efeito nessa variação. O estudo conseguiu apontar ainda, conforme esperado, que a vegetação e os materiais de cobertura urbana desempenham um papel importante, interferindo no clima local. O conhecimento das interferências nas variações de temperatura local pode ser mais um aliado na elaboração de estratégias apropriadas para lidar com os problemas do sobreaquecimento urbano.
Morfologia urbana como um campo interdisciplinar emergente
Authors: Moudon Anne Vernez , Oliveira Vitor
Published: July 2020

Neste artigo identificam-se as forças e os acontecimentos que conduziram à formação do International Seminar on Urban Form (ISUF). O ISUF tem vindo a expandir o campo da morfologia urbana para além dos seus limites originais na área da geografia particularmente em direção aos domínios da arquitetura e do planeamento. Três escolas de morfologia urbana, em Inglaterra, Itália e França, têm vindo a desenvolver um processo de aproximação, seguindo o trabalho seminal de dois morfologistas, M. R. G. Conzen e Saverio Muratori. A aproximação destas escolas fornece as bases para a definição de um campo interdisciplinar e a oportunidade de estabelecer fundações teóricas comuns para um conjunto crescente de morfologistas em diferentes partes do mundo. A ambiciosa missão do ISUF é abordar um conjunto de temas atuais e concretos relacionados com o processo de construção da cidade, fornecendo um fórum de reflexão e ação que inclui disciplinas, e profissões relacionadas, provenientes de diferentes culturas. Neste artigo discute-se o potencial de um campo interdisciplinar de morfologia urbana e o seu contributo para a compreensão e para a gestão dos processos de desenvolvimento urbano num período de transformação sem precedentes.
Uma geografia temporal do encontro
Authors: Netto Vinicius de Moraes , Meirelles João Vitor , Pinheiro Maíra , Lorea Henrique
Published: July 2020

A integração de redes sociais e espaciais é fundamental para novas abordagens a cidades como sistemas de interacção. Neste artigo, propomos uma maneira de analisar as condições espaciais e temporais do encontro como condição da formação de redes sociais. Reunindo abordagens clássicas como a geografia temporal de Hägerstrand e o conceito de segregação como ‘restrição de contato’ de Freeman, e explorações recentes de dados de localização via mídia digital, analisamos a estrutura espaço-temporal de encontros potenciais nas trajetórias urbanas de usuários do Twitter diferenciados por níveis de renda no Rio de Janeiro. Esta abordagem permite estimar as posições dos usuários, visualizar grupos de renda e suas trajetórias no espaço urbano, identificar espaços de encontro potencial e os níveis de diversidade e segregação nos espaços públicos. O artigo conclui com uma discussão dos achados empíricos e a utilidade desta ‘geografia temporal dos encontros’ potenciais na cidade, possível a partir da introdução de novas tecnologias de comunicação digital móvel.
Processo de produção e transformação da forma urbana em cidades costeiras brasileiras
Authors: Munia Benfatti Denio , Tângari Vera Regina
Published: July 2020

O universo da pesquisa nacional, objeto do Projeto Temático FAPESP ‘Espaços livres e forma urbana’, coordenada pelo laboratório QUAPÁ-SEL da FAUUSP, engloba 35 cidades, dentre capitais e cidades de porte médio no Brasil, e se pauta em procedimentos que incluem: pesquisas em rede, individuais e em grupo; oficinas de trabalho nas cidades estudadas; colóquios de pesquisa anuais; divulgação em eventos científicos nacionais e internacionais. Neste artigo são enfocadas cidades localizadas na costa litorânea brasileira onde já ocorreram oficinas e que possibilitaram a sistematização de alguns resultados e uma aproximação de cunho comparativo: Vitória, Salvador, Maceió, Santos e Recife. O texto inclui reflexões sobre o objeto pesquisado e comparações entre as cidades e conclui por indicar para debate possíveis critérios de intervenção para as cidades estudadas que gerem qualidade urbana, resguardadas as situações socioambientais particulares a cada uma. Nesta reflexão, ao invés de discorrer sobre todas as linhas de investigação propostas para as oficinas realizadas pela rede QUAPÁ-SEL, resolvemos traçar um recorte parcial sobre uma pesquisa em andamento, e esta reflexão selecionou apenas parte delas que tem em comum o fato de se situarem na costa brasileira. A reflexão se ateve basicamente aos resultados das oficinas, o que traz para esta análise uma simplificação e ao mesmo tempo uma dificuldade. As oficinas e os respectivos relatos apresentam-se de forma bastante heterogênea e desigual. Entretanto, as discussões foram sempre pautadas em função das mesmas linhas de investigação, assegurando, por outro lado, uma homogeneidade na abordagem.
Verticalizar e ver o mar
Authors: Medeiros Thuany Guedes , Morais Marcele Trigueiro de Araújo , Donegan Lucy
Published: July 2020

Este artigo interroga o processo de ‘fabricação urbana’ do bairro Altiplano Cabo Branco, na cidade de João Pessoa, Brasil. Constata-se um processo acelerado de alteração espacial do Altiplano a partir da aprovação do Decreto nº 5844 em 2007, que instituiu uma Zona Adensável Prioritária em parte do bairro. Esse setor do Altiplano – ocupado por torres residenciais de luxo –, agora chamado ‘Nobre’, é objeto desta investigação, que caracteriza o ambiente construído e identifica os agentes sociais envolvidos neste processo. Quem são esses agentes sociais e como agem no bairro? A que parâmetros os espaços fabricados atendem? Os métodos usados aproximam dimensões espaciais e sociais desta problemática, como: leitura espacial e apreensão da evolução dos espaços físicos da área, entrevistas semiestruturadas e análise de seus conteúdos. Verifica-se uma nítida repercussão em termos de morfologia urbana, conjuntos edificados e espaços públicos, que impacta negativamente na vitalidade urbana do setor. O Estado, enquanto agente social de peso, regulamenta o processo, mas também aparece como copartícipe na difusão de ideias que vinculam os novos empreendimentos a um status social, de bem-estar, segurança e de ‘Ver-o-Mar’. As grandes incorporadoras, por sua vez, beneficiam-se deste envolvimento.
Datas de terra no parcelamento urbano colonial e seu impacto na morfologia urbana
Authors: Corrêa Rodolpho Henrique Corrêa , Pina Silvia Aparecida Mikami Gonçalves , Monteiro Evandro Ziggiatti
Published: July 2020

Na colonização portuguesa da América as vilas fundadas seguiam o princípio de ocupação do território pela cessão das terras comuns dos rossios em parcelas – chamadas datas de terra – mediante a obrigação de se edificar. Estas cessões, juntamente ao processo de arruamento, estabeleciam o uso urbano do solo, materializando parcela e edifício, quadra e rua, dando efetividade ao plano urbano. Este artigo busca compreender a dinâmica de ocupação do território e formação da morfologia urbana baseada nos procedimentos de parcelamento e arruação luso-brasileiros, a partir do caso do núcleo central da cidade de Campinas, Brasil, no período 1815-1859, coincidente com os registros de distribuição das datas de terra pela câmara municipal. Os registros escritos foram compilados e suas informações foram extraídas e cruzadas na forma de grafos, de modo a permitir a geolocalização das parcelas descritas textualmente. Partiu-se, portanto, do registro não-gráfico ao registro gráfico, com a elaboração de mapas que possibilitaram identificar o desenvolvimento da morfologia urbana do núcleo central de Campinas no período. Os resultados obtidos confirmam a potência da análise deste tipo de registro na contribuição para a ciência da morfologia urbana das cidades de matriz portuguesa e das cidades do período colonial brasileiro.
Social sustainability: from accessibility to inclusive design
Authors: Greco Alessandro
Published: July 2020

Usually, articles and books about sustainability in building (and urban) sector are focused on environment, reuse, energy saving, solar and natural energy but the “social” sustainability is not considered as one topic for architects and engineers. But these professionals have to improve the quality of the life of the Human Being and to realize environments in which People can realize themselves safely and independently. The researches at the University of Pavia are focused on solutions to make inclusive the historical buildings and sites, looking for solutions that, at different scale, could be inserted respecting the history and the cultural environment but also improving the chance to visit and live according with the contemporary needs. The article shows the cultural approach and the method applied and some solutions that make clear this philosophy, with the awareness that each historic building and site is a unicum that needs answers that pay attention to the location, the history, the cultural and social background, the real needs and the aim of the complete project.
Reseñas de libros y tesís doctorales
Authors: Varios Autores
Published: July 2020

Libro: NYC relatos gráficos / graphic chronicles. Reseñado por: Pablo Rodríguez-Navarro (Universitat Politècnica de València)

Libro: On the path of Louis Kahn. Reseñado por: Pedro Molina-Siles (Universitat Politècnica de València)

Tesis: Análisis comparativo de la arquitectura gótica  en los reinos de Aragón y Nápoles (S.XIII-XV). Reseñado por: Noelia Cervero Sánchez (Universidad de Zaragoza)

Tesis: Protocolo HBMI para una gestión eficiente del uso público del patrimonio arquitectónico. Reseñado por: María José Viñals Blasco & Jorge Luis García-Valldecabres (Universitat Politècnica de València)

Tesis: Modelos y métodos de participación del usuario en el diseño de productos y servicios. Reseñado por: Marina Puyuelo Cazorla (Universitat Politècnica de València)
Análisis de sequías históricas a través de los impactos derivados
Authors: Sainz de la Maza M. , Del Jesus M.
Published: July 2020

A pesar de que hoy en día la identificación y caracterización de sequías sigue siendo un proceso no estandarizado, lo más habitual es utilizar índices como el SPI o el SPEI entre otros. En este estudio se han analizado sequías históricas, no solo a través de los índices SPI y SPEI, sino también a través del índice SSMI, con series de humedad de suelo simuladas con el modelo hidrológico Variable Infiltration Capacity (VIC). El objetivo es mostrar la importancia de considerar la humedad del suelo en estudios de sequías. La ocurrencia de las sequías se ha determinado a través de los impactos económicos y agrícolas generados, y no únicamente a través del déficit hídrico. Se puede concluir que la humedad del suelo es un factor determinante en el estudio del impacto de la sequía en la producción de cereales y especies de grano grueso, pero no en las pérdidas económicas inducidas.
Transatlantic Market Competition Between Hybrid Carrier and Long-Haul Low-Cost Carrier Business Models
Authors: Renehan Damian , Efthymiou Marina
Published: July 2020

Long-haul low-cost carrier (LHLC) business models are generating considerable interest from the aviation practitioners and academics. Despite the high interest for the LHLC business model, only few have compared the LHLC business model to hybrid carrier business model and studied how airlines can compete with LHLCs. This paper analyses the differences of hybrid and long-haul low-cost carrier models and shows how Aer Lingus airlines has secured its dominant position in the Irish-US market. Product comparison with the help of in-depth interviews with key aviation practitioners as well as secondary data about the capacity and demand of the two carriers in question proves the differences between the two models. Porter five forces model provides an overview of the external competitive environment where the airlines in question operate. The research concluded that the hybrid and long-haul low-cost business model characteristics have many similarities, but also significant differences. It was also discovered that LHLC lack capacity and frequency as well as feeder traffic are very important elements for the transatlantic market. Robust route network including interline traffic and low operating cost, elements present in the hybrid airline business model, ensure profitability.
Reliability Approach to Optimal Thruster Configuration Design for Spacecraft Attitude Control Subsystem
Authors: Ghobadi Mahdi , Shafaee Maziar , Nadoushan Mahdi Jafari
Published: July 2020

An optimal thruster configuration for attitude control subsystem of a spacecraft is presented in this paper. The optimal configuration is designed according to minimum number of required thrusters for satisfying desired reliability with specific redundancy level. The genetic algorithm is employed for optimization process and feasibility of the results is evaluated using algebraic and geometry methods. The main feature of the proposed configuration among feasible configuration with minimum number of required thrusters, which has held to optimal configuration, is that this configuration has maximum reliability and minimum fuel consumption. In addition to feasibility, attitude control performance of some configurations is also examined through the simulation. The results of simulation confirm that the proposed configuration has desirable performance. It is noteworthy to mention that the configuration with maximum number of required thrusters, which is a conventional configuration such that each thruster belongs to only one control channel, has less fuel consumption than optimal configuration. However, the total mass of optimal configuration is less than that of conventional configuration due to a smaller number of thrusters.
Contrasting sources and processes of particulate species in haze days with low and high relative humidity in wintertime Beijing
Authors: Huang Ru-Jin , He Yao , Duan Jing , Li Yongjie , Chen Qi , Zheng Yan , Chen Yang , Hu Weiwei , Lin Chunshui , Ni Haiyan , Dai Wenting , Cao Junji , Wu Yunfei , Zhang Renjian , Xu Wei , Ovadnevaite Jurgita , Ceburnis Darius , Hoffmann Thorsten , O'Dowd Colin D.
Published: July 2020

Abstract. Although there are many studies of particulate matter (PM) pollution in
Beijing, the sources and processes of secondary PM species during haze
periods remain unclear. Limited studies have investigated the PM formation
in highly polluted environments under low- and high-relative-humidity (RH)
conditions. Herein, we present a systematic comparison of species in
submicron particles (PM1) in wintertime Beijing (29 December 2014 to 28 February 2015) for clean periods and pollution periods under low- and high-RH conditions. PM1 species were measured with an aerosol chemical species
monitor (ACSM) and an Aethalometer. Sources and processes for organic
aerosol (OA) were resolved by positive matrix factorization (PMF) with
a multilinear engine 2 (ME-2). The comparisons for clean, low-RH pollution
and high-RH pollution periods are made from three different aspects, namely
(a) mass concentration, (b) mass fraction and (c) growth rate in diurnal
profiles. OA is the dominant component of PM1, with an average mass
concentration of 56.7 µg m−3 (46 %) during high-RH pollution and
67.7 µg m−3 (54 %) during low-RH pollution periods. Sulfate had
higher concentration and mass fraction during high-RH pollution periods,
while nitrate had higher concentration and mass fraction during low-RH
pollution periods. The diurnal variations of nitrate and oxygenated organic
aerosol (OOA) showed a daytime increase in their concentrations during all
three types of periods. Nitrate had similar growth rates during low-RH (0.40 µg m−3 h−1) and high-RH (0.55 µg m−3 h−1)
pollution periods. OOA had a higher growth rate during low-RH pollution
periods (1.0 µg m−3 h−1) than during high-RH pollution
periods (0.40 µg m−3 h−1). In contrast, sulfate had a
decreasing trend during low-RH pollution periods, while it increased
significantly with a growth rate of 0.81 µg m−3 h−1 during
high-RH pollution periods. These distinctions in mass concentrations, mass
fractions and daytime growth rates may be explained by the difference in
the formation processes affected by meteorological conditions. In
particular, photochemical oxidation and aqueous-phase processes may both
produce sulfate and nitrate. The relative importance of the two pathways,
however, differs under different meteorological conditions. Additional OOA
formation under high-RH (> 70 %) conditions suggests
aqueous-related formation pathways. This study provides a general picture of
the haze formation in Beijing under different meteorological conditions.
The stable carbon isotope signature of methane produced by saprotrophic fungi
Authors: Schroll Moritz , Keppler Frank , Greule Markus , Eckhardt Christian , Zorn Holger , Lenhart Katharina
Published: July 2020

Abstract. Methane (CH4) is the most abundant organic compound
in the atmosphere and is emitted from many biotic and abiotic sources.
Recent studies have shown that CH4 production occurs under aerobic
conditions in eukaryotes, such as plants, animals, algae, and saprotrophic
fungi. Saprotrophic fungi play an important role in nutrient recycling in
terrestrial ecosystems via the decomposition of plant litter. Although
CH4 production by saprotrophic fungi has been reported, no data
on the stable carbon isotope values of the emitted CH4
(δ13C-CH4 values) are currently available. In this study, we measured the
δ13C values of CH4 and carbon dioxide (δ13C-CO2 values) emitted by two saprotrophic fungi,
Pleurotus sapidus (oyster mushroom) and Laetiporus sulphureus (sulphur shelf), cultivated on three different
substrates, pine wood (Pinus sylvestris), grass (mixture of Lolium perenne, Poa pratensis, and Festuca rubra), and corn (Zea mays), which reflect
both C3 and C4 plants with distinguished bulk δ13C
values. Applying Keeling plots, we found that the δ13C source
values of CH4 emitted from fungi cover a wide range from −40 to −69 mUr depending on the growth substrate and fungal species. Whilst little
apparent carbon isotopic fractionation (in the range from −0.3 to 4.6 mUr)
was calculated for the δ13C values of CO2 released from
P. sapidus and L. sulphureus relative to the bulk δ13C values of the growth
substrates, much larger carbon isotopic fractionations (ranging from −22
to −42 mUr) were observed for the formation of CH4. Although the two
fungal species showed similar δ13CH4 source values when
grown on pine wood, δ13CH4 source values differed
substantially between the two fungal species when they were grown on grass or corn. We
found that the source values of δ13CH4 emitted by
saprotrophic fungi are highly dependent on the fungal species and the
metabolized substrate. The source values of δ13CH4 cover a
broad range and overlap with values reported for methanogenic archaea, the
thermogenic degradation of organic matter, and other eukaryotes.
Characterizing deepwater oxygen variability and seafloor community responses using a novel autonomous lander
Authors: Gallo Natalya D. , Hardy Kevin , Wegner Nicholas C. , Nicoll Ashley , Yang Haleigh , Levin Lisa A.
Published: July 2020

Abstract. Studies on the impacts of climate change typically focus
on changes to mean conditions. However, animals live in temporally variable
environments that give rise to different exposure histories that can
potentially affect their sensitivities to climate change. Ocean
deoxygenation has been observed in nearshore, upper-slope depths in the
Southern California Bight, but how these changes compare to the magnitude of
natural O2 variability experienced by seafloor communities at short
timescales is largely unknown. We developed a low-cost and spatially
flexible approach for studying nearshore, deep-sea ecosystems and monitoring
deepwater oxygen variability and benthic community responses. Using a
novel, autonomous, hand-deployable Nanolander® with an SBE MicroCAT and camera
system, high-frequency environmental (O2, T, estimated pH) and seafloor
community data were collected at depths between 100 and 400 m off San Diego, CA,
to characterize timescales of natural environmental variability, changes in
O2 variability with depth, and community responses to O2 variability. Oxygen variability was strongly linked to tidal processes,
and contrary to expectation, oxygen variability did not decline linearly
with depth. Depths of 200 and 400 m showed especially high O2
variability; these conditions may give rise to greater community resilience
to deoxygenation stress by exposing animals to periods of reprieve during
higher O2 conditions and invoking physiological acclimation during low
O2 conditions at daily and weekly timescales. Despite experiencing high
O2 variability, seafloor communities showed limited responses to
changing conditions at these shorter timescales. Over 5-month timescales,
some differences in seafloor communities may have been related to seasonal
changes in the O2 regime. Overall, we found lower-oxygen conditions
to be associated with a transition from fish-dominated to
invertebrate-dominated communities, suggesting this taxonomic shift may be a
useful ecological indicator of hypoxia. Due to their small size and ease of
use with small boats, hand-deployable Nanolanders can serve as a powerful
capacity-building tool in data-poor regions for characterizing environmental
variability and examining seafloor community sensitivity to climate-driven
changes.
Influence of microorganisms on initial soil formation along a
glacier forefield on King George Island, maritime Antarctica
Authors: Krauze Patryk , Wagner Dirk , Spinola Diogo Noses , Kühn Peter
Published: July 2020

Abstract. Compared to the 1970s, the edge of the Ecology Glacier on King George Island, maritime Antarctica, is positioned more than 500 m inwards, exposing a large area of new terrain to soil-forming processes and periglacial climate for more than 40 years. To gain information on the state of soil formation and its interplay with microbial activity, three hyperskeletic Cryosols (vegetation cover of 0–80 %) in the recently ( 10 cm. In the foreland of the Ecology Glacier, the main soil-forming processes on a decadal timescale are acidification and accumulation of soil organic carbon and nitrogen, accompanied by changes in microbial abundances, microbial community compositions, and plant coverage, whereas quantifiable silicate weathering and the formation of pedogenic oxides occur on a centennial to a millennial timescale after deglaciation.
Increased carbon capture by a silicate-treated forested watershed affected by acid deposition
Authors: Taylor Lyla L. , Driscoll Charles T. , Groffman Peter M. , Rau Greg H. , Blum Joel D. , Beerling David J.
Published: July 2020

Abstract. Meeting internationally agreed-upon climate targets requires Carbon Dioxide Removal (CDR) strategies coupled with an urgent phase-down of fossil fuel emissions. However, the efficacy and wider impacts of CDR are poorly understood. Enhanced rock weathering (ERW) is a land-based CDR strategy requiring large-scale field trials. Here we show that a low 3.44 t ha−1 wollastonite treatment in an 11.8-ha acid-rain-impacted forested watershed in New Hampshire, USA led to cumulative carbon capture by carbonic acid weathering of 0.025–0.13 t CO2 ha−1 over 15 years. Despite a 0.8–2.4 t CO2 ha−1 logistical carbon penalty from mining, grinding, transportation and spreading, by 2015 weathering together with increased forest productivity led to net CDR of 8.5–11.5 t CO2 ha−1. Our results demonstrate that ERW may be an effective, scalable CDR strategy for acid-impacted forests but at large-scale requires sustainable sources of silicate rock dust.
Efficient multi-scale Gaussian process regression for massive remote sensing data with satGP v0.1.2
Authors: Susiluoto Jouni , Spantini Alessio , Haario Heikki , Härkönen Teemu , Marzouk Youssef
Published: July 2020

Abstract. Satellite remote sensing provides a global view to processes on Earth that has unique benefits compared to making measurements on the ground, such as global coverage and enormous data volume. The typical downsides are spatial and temporal gaps and potentially low data quality. Meaningful statistical inference from such data requires overcoming these problems and developing efficient and robust computational tools.
We design and implement a computationally efficient multi-scale Gaussian process (GP) software package, satGP, geared towards remote sensing applications. The software is able to handle problems of enormous sizes and to compute marginals and sample from the random field conditioning on at least hundreds of millions of observations. This is achieved by optimizing the computation by, e.g., randomization and splitting the problem into parallel local subproblems which aggressively discard uninformative data. We describe the mean function of the Gaussian process by approximating marginals of a Markov random field (MRF). Variability around the mean is modeled with a multi-scale covariance kernel, which consists of Matérn, exponential, and periodic components. We also demonstrate how winds can be used to inform covariances locally.
The covariance kernel parameters are learned by calculating an approximate marginal maximum likelihood estimate, and the validity of both the multi-scale approach and the method used to learn the kernel parameters is verified in synthetic experiments. We apply these techniques to a moderate size ozone data set produced by an atmospheric chemistry model and to the very large number of observations retrieved from the Orbiting Carbon Observatory 2 (OCO-2) satellite. The satGP software is released under an open-source license.
User-oriented hydrological indices for early warning system. Validation using post-event surveys: flood case studies on the Central Apennines District
Authors: Lombardi Annalina , Colaiuda Valentina , Verdecchia Marco , Tomassetti Barbara
Published: July 2020

Abstract. Flood and flash floods are complex events, depending on weather dynamics, basin physiographical characteristics, land use cover and water management. For this reason, prediction of such events usually deals with very accurate model tuning and validation, which is usually site-specific and based on climatological data, such as discharge time series or flood databases. In this work, we developed and tested two hydrological stress indices for flood detection in the Central Italy Apennine District: a heterogeneous geographical area, characterized by complex topography and medium-to-small catchment extension. Proposed indices are threshold-based and developed taking into account operational requirements of civil protection end-users. They are calibrated and tested through the application of signal theory, in order to overcome data scarcity over ungauged areas, as well as incomplete discharge time series. The validation has been carried out on a case study basis, through the use of flood reports from various source of information, as well as hydrometric level time series, which represent the actual hydrological quantity monitored by civil protection operators. Obtained results shows as the overall accuracy of flood prediction is greater than 0.8, with false alarm rates below 0.5 and probability of detection ranging from 0.51 to 0.80. A slight anticipation of peak occurrence was found, however, the time shift of indices signal peak it is strongly dependent on the presence of dams that regulates the flood propagation. Moreover, the different nature of the proposed indices suggests their application in a complementary way, as the index based on drained precipitation appears to be more sensible to rapid flood propagation in small tributaries, while the discharge-based index is particularly responsive to main channel dynamics.
Exploring the regolith with electrical resistivity tomography in largescale
surveys: electrode spacing related issues and possibility
Authors: Gourdol Laurent , Clément Rémi , Juilleret Jérôme , Pfister Laurent , Hissler Christophe
Published: July 2020

Abstract. Within the Critical Zone, regolith plays a key role in the fundamental hydrological functions of water collection, storage, mixing and release. Electrical Resistivity Tomography (ERT) is recognized as a remarkable tool for characterizing the geometry and properties of the regolith, overcoming limitations inherent to conventional borehole-based investigations. For exploring shallow layers, a small electrode spacing (ES) will provide a denser set of apparent resistivity measurements of the subsurface. As this option is cumbersome and time-consuming, smaller ES – albeit offering poorer shallow apparent resistivity data – are often preferred for large horizontal ERT surveys. To investigate the negative trade-off between larger ES and reduced accuracy of the inverted ERT images for shallow layers, we use a set of synthetic conductive/resistive/conductive three-layered soil–saprock/saprolite–bedrock models in combination with a reference field dataset. Our results suggest that an increase in ES causes a deterioration of the accuracy of the inverted ERT images in terms of both resistivity distribution and interface delineation and, most importantly, that this degradation increases sharply when the ES exceeds the thickness of the top subsurface layer. This finding, which is obvious for the characterization of shallow layers, is also relevant even when solely aiming for the characterization of deeper layers. We show that an oversized ES leads to overestimations of depth to bedrock and that this overestimation is even more important for subsurface structures with high resistivity contrast. To overcome this limitation, we propose adding interpolated levels of surficial apparent resistivity relying on a limited number of ERT profiles with a smaller ES. We demonstrate that our protocol significantly improves the accuracy of ERT profiles when using large ES, provided that the top layer has a rather constant thickness and resistivity. For the specific case of large-scale ERT surveys the proposed upgrading procedure is cost-effective in comparison to protocols based on small ES.
Historical Northern Hemisphere snow cover trends and projected changes in the CMIP6 multi-model ensemble
Authors: Mudryk Lawrence , Santolaria-Otín María , Krinner Gerhard , Ménégoz Martin , Derksen Chris , Brutel-Vuilmet Claire , Brady Mike , Essery Richard
Published: July 2020

Abstract. This paper presents an analysis of observed and simulated historical
snow cover extent and snow mass, along with future snow cover
projections from models participating in the World
Climate Research Programme Coupled Model Intercomparison Project
Phase 6 (CMIP6). Where appropriate, the CMIP6 output is compared to CMIP5
results in order to assess progress (or absence thereof) between
successive model generations. An ensemble of six observation-based
products is used to produce a new time series of historical Northern
Hemisphere snow extent anomalies and trends; a subset of four of these
products is used for snow mass. Trends in snow extent over 1981–2018
are negative in all months and exceed -50×103 km2 yr−1 during November, December, March, and May. Snow
mass trends are approximately −5 Gt yr−1 or more for all
months from December to May. Overall, the CMIP6 multi-model ensemble
better represents the snow extent climatology over the 1981–2014
period for all months, correcting a low bias in CMIP5. Simulated snow
extent and snow mass trends over the 1981–2014 period are stronger in
CMIP6 than in CMIP5, although large inter-model spread remains in the
simulated trends for both variables. There is a single linear
relationship between projected spring snow extent and global surface
air temperature (GSAT) changes, which is valid across all CMIP6 Shared
Socioeconomic Pathways. This finding suggests that Northern Hemisphere
spring snow extent will decrease by about 8 % relative to the
1995–2014 level per degree Celsius of GSAT increase. The
sensitivity of snow to temperature forcing largely explains the
absence of any climate change pathway dependency, similar to other
fast-response components of the cryosphere such as sea ice and near-surface permafrost extent.
Climate change and Northern Hemisphere lake and river
ice phenology
Authors: Newton Andrew M. W. , Mullan Donal
Published: July 2020

Abstract. At high latitudes and altitudes one of the main controls on hydrological and biogeochemical processes is the breakup and freezeup of lake and river ice. This study uses ~2600 time series from across 644 Northern Hemisphere lakes and river to explore historical patterns in lake and river ice phenology across four time periods (1931–1960, 1961–1990, 1991–2005, and 1931–2005). These time series show later breakup dates by 0.6 days per decade from 1931–2005 across North America and Europe, with trends closely correlating with temperature. Freezeup trends are more spatiotemporally complex with those in Europe negligible compared to later freezeup trends for North America. For the most recent time period (1991–2005) high magnitude trends towards later freezeup that are considerably larger than in other time periods are observed. Freezeup trends show a more limited correlation with climate and this is likely because freezeup is not guaranteed to occur simply by temperatures dropping below 0 °C. Across the Northern Hemisphere the length of the open water season is shown to have increased through time, with the magnitude at its largest in the most recent time period. These results provide an important contribution that can be used to help understand how ice phenology patterns may change in the future with an expected rise in global mean air temperatures. Observations of an acceleration in warming trends through time shows the importance of non-linear responses to climate forcings. This will be crucial because it is probable that lake and river ice phenology changes, brought about by rising air temperatures, may in turn begin to feedback into the climate system. Thus, understanding historical changes, causes, and consequences is required to fully unravel the potential implications of future ice phenology change.
Pesticide Exposure: The Case of Open-field and Greenhouse Workers
Authors: Esechie Jovita O.
Published: July 2020

A study was conducted among greenhouse and open field pesticide workers at the Batinah Coast of Oman in 2008 - 2009 to compare their level of pesticide exposure. A total of 74 greenhouse and 79 open field pesticide workers using pesticide mixtures consisting mostly of organophosphates were interviewed. Eighteen self-reported toxicity symptoms were recorded, with 9 and 3 of them being more prevalent among the greenhouse and open field workers, respectively. Although toxicity symptoms were generally higher among the greenhouse workers, it was observed that many of them indulged in smoking and gum chewing during pesticide application and these habits may have contributed to increased exposure. Most of the workers complained of discomfort when using protective devices, therefore it is recommended that protective materials adapted to the climate and socio-economic conditions of the pesticide workers be developed, and that they be encouraged to use them through appropriate educational efforts and incentives.
Authors: Maquieira V. Carlos , Niño T. Jorge
Published: July 2020

This article studies the impact of the Chilean tax law on the company capital structure. The study develops a model whose assumptions are very similar to those employed by Modigliani and Miller (1958, 1963) and Miller (1977). In Chile, the debt tax shield is positively related to the cost of capital of the firm and the time horizon of the investors. On the other hand, the payout ratio is negatively related to the debt tax shield. This result might suggest that the dividend policy is not independent of the capital structure decision.
Authors: Gregoire C. Jorge , Zurita L. Salvador
Published: July 2020

The purpose of this note is to clarify an aspect of linear algebra that appears in the development of Ross 1976's arbitration theory, as presented, for example, in Copeland and Weston 1988.
Authors: Acuña A. Eduardo , Alburquerque F. Mario
Published: July 2020

The present paper aims at developing a conceptual framework for the analysis of modernization of labor relations in Chile at the level of firms. The first part is a review of the bibliography on the subject, from which characteristics and action patterns of modernizations are defined. From the analysis of the bibliography some basic components of modernization are proposed as suitable instruments for empirical research. Several hypotheses on the development of modernization of labor relations in Chilean firms are presented, with an emphasis on the influence of certain factors on modernization processes, environmental pressures, characteristics of firms, and the degree and forms of participation of social actors, especially entrepreneurs and workers. The contents seek to increase the understanding of change in labor relations in Chile, by providing clues on efforts to modernize this kind of relations.
The Determinants of the Choice of Preferred Providers among the Publicly Insured in Chile: an Empirical Analysis
Authors: Henríquez H. Ricardo
Published: July 2020

This paper analyses the determinants of the choice of provider among the publicly insured in Chile. The focus is on the Preferred Provider System (PPS) where public insured can opt for a more consumer-oriented environment subject to a higher level of copayments. Using a model of expected utility gain we develop a logit analysis based on a large multipurpose survey, the Encuesta de Caracterización Socioeconómica Nacional, CASEN 1992 (National Survey for Socioeconomic Characterisation). We make use of several socio-economic, demographic and access variables in our econometric estimation. As a whole, our results adjust to the hypotheses formulated. Among others, individuals’ income, the relative value of copayments, waiting time and zone of residence emerge as the most relevant determinants in the decision process. The positive effect of income would indicate some degree of segmentation within the public system, while the impact of the relative value of copayments shows that user charges can act as an important deterrent for some individuals. The unexpected negative effect of waiting time, included in our estimation as a provider’s attribute, would suggest certain level of captivity in the sense that some individuals have no real choices but purely public provision. The result for zone of residence indicates that rural residents are less likely to choose preferred providers than urban residents. This result is explained by the spatial distribution of preferred providers who tend to cluster in urban areas.
Authors: Urrutia Jorge L. , Vu Joseph
Published: July 2020

This paper investigates the time series properties of the return of American Depository Receipts (ADRs) issued by Latin American companies. Specifically, we examine the presence of nonlinear trends and chaos. The motivation of the paper is twofold: First, we use a micro data set, wich can avoid the problems encountered by previous research of nonlinearity an chaos in micro financial data. Second, we choose returns of Latin American ADRs because of its unique characteristics, wich might make them to behave differently from the U.S. capital market as a whole. Even though the powerful BDS statistic strongly suggests the presence of nonlinearity in the Latin American ADRs returns. The BDS statistics, applied to the standardized residuals of the EGARCH model, rejects heteroskedasticity as the cause of nonlinearity. On the other hands, the locally weighted regression indicates the presence of chaos in the Latin American ADRs returns. Our results are relevant because previous research has failed to report evidence of chaos in stock returns.
Authors: Raineri B. Andrés
Published: July 2020

Globalization has brought an intensification of competition throughout most of the world. These new winds of competition have brought threats to local companies in the forms of new entrants in their markets, new technologies, and regulatory shifts. All these changes have pressed local companies to either adapt to the new reality or disappear from the market. An extensive literature has been developed of how organizations should better cope with change. Literature on organizational change is frequently suggesting the use a set of "behavioral practices" that should help in the management of change processes and the administration of resistances from within the organization (Kanter, Stein, y Jick, 1992; Dauphinais y Pederson, 1995; Nadler, 1998). The use of these practices should help firms be more flexible and adaptive to environmental threats. This paper, which is exploratory and descriptive in nature, compares the use of such practices within and between firms varying in their size, as measured by number of employees. Results showed that some practices were used more frequently than others. In particular, practices related to the preparation for change were more frequently used than change implementation practices. It was also observed that larger firms, in comparison to smaller firms, used in a greater proportion change management practices. These relations could be better explained when it was demonstrated that these differences are originated specifically in the larger use that big companies have of practices related to preparing for the change process (diagnosis, strategic planning, et cetera). Several possible arguments are discussed in an attempt to explain the findings.
Authors: Araya Alvaro , Islas Gonzalo , Maquieira V. Carlos
Published: July 2020

Within financial literature aimed at analyzing agency issues, a particularly interesting aspect of it corresponds to the conflict that arises between stockholders and bondholders. There is a fair amount of literature that dissects the different manifestations or outcomes that such a conflict might generate, as well as the possible ways of solving these, one of which is the use of covenants in debt contracts. This paper presents a discussion in the main features of the stockholder-bondholder conflict, a description of the regulatory framework of bond issuance in Chile and a clinical assessment of the characteristics of the covenants used in Chile, from 1987 to 2000, specially emphasizing of certain specific clauses in the Chilean debt market. This paper shows that the covenants most widely used in the Chilean Market, are those related to the claim dilution problem (83% of the contracts restrict the either financial policy or the capital structure).
Authors: Parisi F. Antonino , Parisi F. Franco
Published: July 2020

In the Chilean exchange rate market, composed by sophisticated institutional investors and under different models of intervention of Central Bank, it is possible to obtain abnormal returns with the use of technical analysis and autoregresive models. The findings are similar to those observed in other international markets, but they were not the expected by the authors, since the low number of participants in this market, the high volatility due to deep international financial crises and the significant changes in this market introduced by the Central Bank. In effect, in the last third of the sample, the volatility of the exchange rate increased significantly and the abnormal returns obtained under the technical analysis and autoregressine models were equivalent to 60% approximately of the total sample. This period corresponds to the decision of the Chilean Central Bank to intervine in the exchange rate market as a result of the economic crisis in Argentina. Also, we did not observed statistical difference between the exchange rate and the forecasted by the autoregressive models, result that was validated by parametric and nonparametric test.
Exchange Rate Exposure and Optimal Hedging Strategies when Interest Rates are Stochastic: a Simulation-Based Approach
Authors: Castillo R. Augusto
Published: July 2020

In this paper i analyze the problem faced by an investor expecting to receive a cash flow in a foreign currency. The investor is assumed to be exposed to long-term exchange rate risk, having no access to long-term forward contracts to hedge perfectly. Under non stochastic interest rates the investor is able to hedge perfectly using short-term forward contracts, but perfect hedging is not possible when we consider interest rates to be stochastic. I present here a simulation-based methodology to obtain optimal hedging under stochastic interest rates (i.e. when perfect hedging can not be reached). Then, i explore how we quality of the hedging to be reached depends on some key factors such as the volatility of the exchange rate, the volatility of the interest rates, and the degree of correlation among the stochastic variables considered.
Authors: Marshall Pablo , Arnold Ignacio
Published: July 2020

This paper considers the loyalty and inheritance effects in the news program of the open television in Chile. The study uses data from the People Meter system to measures the loyalty and inheritance effects concepts for different television channels and different socio-demographic groups. The results of the study show significant differences in loyalty and inheritance effects across channels and sociodemographic groups. The paper represents a contribution, not only for this specific data set. It also gives a methodological contribution in the analysis of other data sets from the People Meter system.
Authors: Carrasco Omar F. , Johnson Christian A. , Núñez Hugo A.
Published: July 2020

This paper analyzes the determinants of investment in Chile from the microeconomic perspective, using a sampling data with 36 firms for 1992 to 2003. Applying panel data econometric techniques with alternative econometric methodologies, we concluded that the main idiosyncratic variables for investment were total assets, operational profits, liquidity, and the Tobin’s Q. At macroeconomic level significant variables were interest rate and GDP.