Browsing by Subject "North America"

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  • Taylor, G.; Hillers, G. (2020)
    We present a new method for estimating time-series of relative seismic velocity changes (dv/v) within the Earth. Our approach is a Markov chain Monte Carlo (MCMC) technique that seeks to construct the full posterior probability distribution of the dv/v variations. Our method provides a robust, computationally efficient way to compute dv/v time-series that can incorporate information about measurement uncertainty, and any prior constraints that may be available. We demonstrate the method with a synthetic experiment, and then apply the MCMC algorithm to three data examples. In the first two examples we reproduce dv/v time-series associated with the response to the 2010 M 7.2 El Mayor-Cucapah earthquake at two sites in southern California, that have been studied in previous literature. In the San Jacinto fault zone environment we reproduce the dv/v signature of a deep creep slip sequence triggered by the El Mayor-Cucapah event, that is superimposed on a strong seasonal signal. At the Salton Sea Geothermal Field we corroborate the previously observed drop-and-recovery in seismic velocity caused by ground shaking related to the El Mayor-Cucapah event. In a third, new example we compute a month long velocity change time-series at hourly resolution at Pinion Flat, California. We observe a low amplitude variation in seismic velocity with a dominant frequency of 1 cycle per day, as well as a second transient signal with a frequency of 1.93 cycles per day. We attribute the 1-d periodicity in the dv/v variation to the combined effects of the diurnal tide and solar heating. The frequency of the signal at 1.93 cycles per day matches that of the lunar (semi-diurnal) tide. Analysis of the uncertainties in the Pinion Flat time-series shows that the error contains a signal with a frequency of 1 cycle per day. We attribute this variation to seismic noise produced by freight trains operating within the Coachella Valley. By demonstrating the applicability of the MCMC method in these examples, we show that it is well suited to tackle problems involving large data volumes that are typically associated with modern seismic experiments.
  • Shu, Song; Liu, Hongxing; Beck, Richard A.; Frappart, Frédéric; Korhonen, Johanna; Lan, Minxuan; Xu, Min; Yang, Bo; Huang, Yan (Copernicus Publications / European Geosciences Union, 2021)
    Hydrology and Earth System Sciences Discussions 25:3
    A total of 13 satellite missions have been launched since 1985, with different types of radar altimeters on board. This study intends to make a comprehensive evaluation of historic and currently operational satellite radar altimetry missions for lake water level retrieval over the same set of lakes and to develop a strategy for constructing consistent long-term water level records for inland lakes at global scale. The lake water level estimates produced by different retracking algorithms (retrackers) of the satellite missions were compared with the gauge measurements over 12 lakes in four countries. The performance of each retracker was assessed in terms of the data missing rate, the correlation coefficient r, the bias, and the root mean square error (RMSE) between the altimetry-derived lake water level estimates and the concurrent gauge measurements. The results show that the model-free retrackers (e.g., OCOG/Ice-1/Ice) outperform the model-based retrackers for most of the missions, particularly over small lakes. Among the satellite altimetry missions, Sentinel-3 gave the best results, followed by SARAL. ENVISAT has slightly better lake water level estimates than Jason-1 and Jason-2, but its data missing rate is higher. For small lakes, ERS-1 and ERS-2 missions provided more accurate lake water level estimates than the TOPEX/Poseidon mission. In contrast, for large lakes, TOPEX/Poseidon is a better option due to its lower data missing rate and shorter repeat cycle. GeoSat and GeoSat Follow-On (GFO) both have an extremely high data missing rate of lake water level estimates. Although several contemporary radar altimetry missions provide more accurate lake level estimates than GFO, GeoSat was the sole radar altimetry mission, between 1985 and 1990, that provided the lake water level estimates. With a full consideration of the performance and the operational duration, the best strategy for constructing long-term lake water level records should be a two-step bias correction and normalization procedure. In the first step, use Jason-2 as the initial reference to estimate the systematic biases with TOPEX/Poseidon, Jason-1, and Jason-3 and then normalize them to form a consistent TOPEX/Poseidon–Jason series. Then, use the TOPEX/Poseidon–Jason series as the reference to estimate and remove systematic biases with other radar altimetry missions to construct consistent long-term lake water level series for ungauged lakes.
  • Global Burden of Disease Self-Harm Collaboration; Orpana, H.M.; Doku, D.T.; Meretoja, T.J.; Shiri, R.; Vasankari, T. (2019)
    Objectives To use the estimates from the Global Burden of Disease Study 2016 to describe patterns of suicide mortality globally, regionally, and for 195 countries and territories by age, sex, and Socio-demographic index, and to describe temporal trends between 1990 and 2016. Design Systematic analysis. Main outcome measures Crude and age standardised rates from suicide mortality and years of life lost were compared across regions and countries, and by age, sex, and Socio-demographic index (a composite measure of fertility, income, and education). Results The total number of deaths from suicide increased by 6.7% (95% uncertainty interval 0.4% to 15.6%) globally over the 27 year study period to 817 000 (762 000 to 884 000) deaths in 2016. However, the age standardised mortality rate for suicide decreased by 32.7% (27.2% to 36.6%) worldwide between 1990 and 2016, similar to the decline in the global age standardised mortality rate of 30.6%. Suicide was the leading cause of age standardised years of life lost in the Global Burden of Disease region of high income Asia Pacific and was among the top 10 leading causes in eastern Europe, central Europe, western Europe, central Asia, Australasia, southern Latin America, and high income North America. Rates for men were higher than for women across regions, countries, and age groups, except for the 15 to 19 age group. There was variation in the female to male ratio, with higher ratios at lower levels of Socio-demographic index. Women experienced greater decreases in mortality rates (49.0%, 95% uncertainty interval 42.6% to 54.6%) than men (23.8%, 15.6% to 32.7%). Conclusions Age standardised mortality rates for suicide have greatly reduced since 1990, but suicide remains an important contributor to mortality worldwide. Suicide mortality was variable across locations, between sexes, and between age groups. Suicide prevention strategies can be targeted towards vulnerable populations if they are informed by variations in mortality rates. © Published by the BMJ Publishing Group Limited.
  • Lintulaakso, Kari; Polly, P.D.; Eronen, Jussi (2019)
    Aim We use cluster analysis to delimit climatically and functionally distinct mammalian faunal clusters. These entities form regional species pools and are relevant to community assembly processes. Similar clusters can be differentiated in the fossil record, offering the potential for use as palaeoenvironmental proxies. Location North America within W178 degrees, W14 degrees, N83 degrees, N7 degrees and Europe within W32 degrees, E35 degrees, N80 degrees, N35 degrees. Major taxa studied 575 and 124 land mammal species from North America and Europe. Methods K-means clustering was used to subdivide North America and Europe into distinct faunas ranging in number from 3 (largest scale) to 21 (smallest scale). Each set of faunas was tested for significant differences in climate (mean annual precipitation, mean annual temperature) and functional traits (body mass, locomotion and diet). Results In North America, climatic differentiation exists at the scale where mammals are divided into 11 or fewer distinct faunas and, in Europe, at the scale where there are five or fewer faunas. Functional trait differentiation in body mass occurs at a larger spatial scale in North America (8 distinct faunas), but locomotor differentiation is present at all spatial scales, and dietary differentiation is not present at any scale. No significant differentiation in any functional trait at any scale was found in Europe. Main conclusions Faunal clusters can be constructed at any spatial scale, but clusters are climatically and functionally meaningful only at larger scales. Climatic (and environmental) differences and their associated functional trait specialisations are likely to be barriers to large-scale mixing. We argue, therefore, that functionally and climatically distinct faunal clusters are the entities that form regional species pools for community assembly processes. In North America, there are eight such mammal pools, but only one in Europe. Since the functional traits in our study are observable in the fossil record, functional trait analysis can potentially be used to diagnose climatically distinct regions in the past.
  • Virtanen, Aino (Helsingfors universitet, 2013)
    Corporate Social Responsibility (CSR) addresses the responsibility of companies for their impacts on society. The concept of strategic CSR is becoming increasingly mainstreamed in the forest industry, but there is, however, little consensus on the definition and implementation of CSR. The objective of this research was to build knowledge on the characteristics of CSR and to provide insights on the emerging trend to increase the credibility and legitimacy of CSR through standardization. The study explored how the sustainability managers of European and North American forest companies perceive CSR and the recently released international ISO 26000 guidance standard on social responsibility. The conclusions were drawn from an analysis of two data sets; multivariate survey data based on one subset of 30 European and 13 North American responses, and data obtained through in-depth interviewing of 10 sustainability managers that volunteered for a phone interview about social responsibility practices at their company. The analysis concluded that there are no major differences in the characteristics of cross-Atlantic CSR. Regarding the components of CSR, environmental issues and organizational governance were key priorities in both regions, whereas consumer issues, human rights, and financial issues were among the least addressed categories. Regarding ISO 26000 guidance standard, the study revealed that there were varying perceptions, both positive and negative. Moreover, sustainability managers of European and North American forest companies were still uncertain regarding the applicability of the ISO 26000 guidance standard to the forest industry. The findings are in line with the earlier research that suggests that as an extractive industry, the forest-based industry tends to address environmental issues as a priority area of CSR. The results are also consistent with previous research that suggests that CSR is a case- and company-specific concept. This study is among the first to provide a preliminary review of the practical implications of the ISO 26000 standard in the forest sector. The results may be utilized by sustainability managers interested in the best practices on CSR, and also by a variety of forest industrial stakeholders interested in the practical outcomes of the long-lasting CSR debate.
  • Menzel, Frank; Vilkamaa, Pekka (2021)
    The following species of the genus Lycoriella Frey sensu Vilkamaa & Menzel from the Holarctic region are newly described and illustrated: Lycoriella ampla sp. n. (Canada: Ontario), L. barkalovi sp. n. (Russia: Krasnoyarsk region), L. canningsi sp. n. (Canada: British Columbia), L. eurystylata sp. n. (Canada: Quebec), L. excavata sp. n. (USA: Colorado), L. jakovlevi sp. n. (Russia: Karelia), L. kinbasketi sp. n. (Canada: British Columbia), L. longa sp. n. (USA: Colorado), L. nivicola sp. n. (Canada: Nunavut, NWT; Greenland), L. pearyi sp. n. (Greenland), L. taimyrensis sp. n. (Russia: Krasnoyarsk region) and L. tundrae sp. n. (Russia: Krasnoyarsk region). Lycoriella parva (Holmgren, 1869) is redescribed and illustrated and new faunistic records are given for some previously described species of Lycoriella. The newly described species raise the number of known species of Lycoriella from 38 to 50.
  • García-Girón, Jorge; Heino, Jani; Iversen, Lars Lønsmann; Helm, Aveliina; Alahuhta, Janne (Elsevier, 2021)
    Science of The Total Environment 786 (2021), 147491
    Patterns of species rarity have long fascinated ecologists, yet most of what we know about the natural world stems from studies of common species. A large proportion of freshwater plant species has small range sizes and are therefore considered rare. However, little is known about the mechanisms and geographical distribution of rarity in the aquatic realm and to what extent diversity of rare species in freshwater plants follows their terrestrial counterparts. Here, we present the first in–depth analysis of geographical patterns, potential deterministic ecogeographical factors and projected scenarios of freshwater vascular plant rarity using 50 × 50 km grid cells across Europe (41°N–71°N) and North America (25°N–78°N). Our results suggest that diversity of rare species shows different patterns in relation to latitude on the two continents, and that hotspots of rarity concentrate in a relatively small proportion of the European and North American land surface, especially in mountainous as well as in climatically rare and stable areas. Interestingly, we found no differences among alternative rarity definitions and measures when delineating areas with notably high diversity of rare species. Our findings also indicate that few variables, namely a combination of current climate, Late Quaternary climate–change velocity and human footprint, are able to accurately predict the location of continental centers of rare species diversity. However, these relationships are not geographically homogeneous, and the underlying factors likely act synergistically. Perhaps more importantly, we provide empirical evidence that current centers of rare species diversity are characterized by higher anthropogenic impacts and might shrink disproportionately within this century as the climate changes. Our reported distributional patterns of species rarity align with the known trends in species richness of other freshwater organisms and may help conservation planners make informed decisions mitigating the effects of climate change and other anthropogenic impacts on biodiversity.
  • Fukushima, Caroline Sayuri; Mendoza, Jorge Ivan; West, Rick C.; Longhorn, Stuart; Rivera, Emmanuel; Cooper, Ernst W. T.; Henaut, Yann; Henriques, Sergio; Cardoso, Pedro (2019)
    Background CITES is an international agreement between governments to ensure that international trade in specimens of wild animals and plants does not threaten their survival. Regarding spiders, all species listed in CITES are tarantulas. They are included in Appendix II, meaning that they are species that are not necessarily now threatened with extinction but that they may become so unless trade is closely controlled. Many tarantulas are legally and illegally traded in the pet market and they are one of the most traded invertebrate groups. Originally, the CITES list published in 1995 included all the current species of the genus Brachypelma Simon, 1891 plus Aphonopelma pallidum (F. O. Pickard-Cambridge, 1897) and the so-called Aphonopelma albiceps (Pocock, 1903). After that, some taxonomic changes were done, as well as descriptions of new species in the genus Brachypelma. The objective of this paper is to assess the 21 taxonomically valid spider species listed on CITES according to the IUCN criteria, study the general patterns and trends and advise on possible future conservation actions critical for the survival of endangered species. New information Amongst all 21 species assessed, 16 had sufficient data on their distribution, ecology and threats to properly understand their current status and suggest possible conservation measures. A decline in the area of occupancy (AOO) and extent of occurrence (EOO) was inferred to almost all species, caused mostly by human activities (urbanisation, roads, agricultural and touristic activities), which often lead to the complete loss of subpopulations across their range. Hurricanes and frequent rising water, which are increasing in frequency due to climate change, can cause decline in habitat quality and consequent change in EOO and AOO of some species and should also be considered when planning conservation actions. Severe fragmentation was detected in 13 species and is therefore one of the most relevant threats to the most endangered Brachypelma species and should be made a priority aspect to deal with when proposing conservation actions for the group. Regarding the loss of individuals in wild populations, the main cause seems to be the overharvesting to meet the illegal trade. The most important conservation actions identified across species include preserving their natural habitat through protected areas, establishing management plans for both the species and their habitats and undertaking systematic monitoring to provide information about population recovery and species re-introduction programmes. In general, we propose to prioritise and support research on the population trends and distribution, as well as on the impact of land use and habitat degradation. Special attention regarding conservation actions and research plans has to be given to the central Pacific coastal area of Mexico, particularly around Guerrero State where five species of Brachypelma occur. Critically, for some of the most endangered species, such as B. baumgarteni and B. hamorii, there is no official protected area in their range of occurrence. It would therefore be highly recommended to establish at least one conservation unit which focuses on protecting each of these species in situ. In some cases, basic taxonomic research is needed before development of any appropriate conservation action can be proposed.
  • McVeigh, Tytti (Helsingfors universitet, 2015)
    This thesis investigates the development of the visibility of slavery in the brochures of four Virginia plantations over a time period of 90 years. The four plantations are Monticello, Mount Vernon, Belle Grove, and Long Branch, all of different sizes but with similar pasts as sites of enslavement prior to the abolishment of slavery in 1865. The goal is to discover how and why the narrative of slavery has changed over the years, and if any larger societal changes may have contributed to this development. As tour brochures have the ability to affect a visitor’s interpretation of a site, it is important to understand what type of discourses and images are directing the visitor’s gaze in the brochures. It is equally vital to attempt to understand the reasoning behind those choices of language and imagery. In this thesis, Critical Discourse Analysis (CDA) is used to discover what is being said, what is left unsaid, and why those decisions were made. The primary sources for this thesis are the print brochures collected at each plantation and the plantation websites. The material is primarily analyzed using textual analysis although some image analysis is also included to give a more comprehensive understanding of the content of the brochures. In addition, secondary sources are used to support the historical and conceptual framework of the thesis. The main result of this thesis is that the visibility of slavery in plantation brochures has developed from non-existent or minimal to attempted integration. Until the late 1970s the institution of slavery and the experiences of the enslaved, if mentioned, are trivialized, marginalized, and/or segregated. Slow but steady progress in increasing the presence of slavery in the brochures can be witnessed throughout the years as the general opinion in the United States became more accepting, even demanding, of racial equality. No individual event or phenomenon has had a direct impact on the content of the brochures but a clear development into including slavery can be seen. Based on the results, it is the conclusion of this thesis that the main themes of the brochures have not changed very much since the 1920s. Owner families, prestigious guests, architecture, gardens, and the achievements of the wealthy owners have remained the main focus of attention although some new themes can be found in the more recent brochures. It is also evident that these themes persist at the expense of others, such as slavery, bringing about an interesting discussion of remembering and forgetting. In addition, these conclusions raise an important question about the roles of plantation museums as educators, entertainers, and research facilities.
  • Li, Tong; Zhang, Mingyang; Li, Yong; Lagerspetz, Eemil; Tarkoma, Sasu; Hui, Pan (2021)
    The outbreak of Covid-19 changed the world as well as human behavior. In this article, we study the impact of Covid-19 on smartphone usage. We gather smartphone usage records from a global data collection platform called Carat, including the usage of mobile users in North America from November 2019 to April 2020. We then conduct the first study on the differences in smartphone usage across the outbreak of Covid-19. We discover that Covid-19 leads to a decrease in users' smartphone engagement and network switches, but an increase in WiFi usage. Also, its outbreak causes new typical diurnal patterns of both memory usage and WiFi usage. Additionally, we investigate the correlations between smartphone usage and daily confirmed cases of Covid-19. The results reveal that memory usage, WiFi usage, and network switches of smartphones have significant correlations, whose absolute values of Pearson coefficients are greater than 0.8. Moreover, smartphone usage behavior has the strongest correlation with the Covid-19 cases occurring after it, which exhibits the potential of inferring outbreak status. By conducting extensive experiments, we demonstrate that for the inference of outbreak stages, both Macro-F1 and Micro-F1 can achieve over 0.8. Our findings explore the values of smartphone usage data for fighting against the epidemic.
  • Amesbury, Matthew J.; Booth, Robert K.; Roland, Thomas P.; Bunbury, Joan; Clifford, Michael J.; Charman, Dan J.; Elliot, Suzanne; Finkelstein, Sarah; Garneau, Michelle; Hughes, Paul D. M.; Lamarre, Alexandre; Loisel, Julie; Mackay, Helen; Magnan, Gabriel; Markel, Erin R.; Mitchell, Edward A. D.; Payne, Richard J.; Pelletier, Nicolas; Roe, Helen; Sullivan, Maura E.; Swindles, Graeme T.; Talbot, Julie; van Bellen, Simon; Warner, Barry G. (2018)
    Fossil testate amoeba assemblages have been used to reconstruct peatland palaeohydrology for more than two decades. While transfer function training sets are typically of local-to regional-scale in extent, combining those data to cover broad ecohydrological gradients, from the regional-to continental- and hemispheric-scales, is useful to assess if ecological optima of species vary geographically and therefore may have also varied over time. Continental-scale transfer functions can also maximise modern analogue quality without losing reconstructive skill, providing the opportunity to contextualise understanding of purely statistical outputs with greater insight into the biogeography of organisms. Here, we compiled, at moderate taxonomic resolution, a dataset of nearly 2000 modern surface peatland testate amoeba samples from 137 peatlands throughout North America. We developed transfer functions using four model types, tested them statistically and applied them to independent palaeoenvironmental data. By subdividing the dataset into eco-regions, we examined biogeographical patterns of hydrological optima and species distribution across North America. We combined our new dataset with data from Europe to create a combined transfer function. The performance of our North-American transfer function was equivalent to published models and reconstructions were comparable to those developed using regional training sets. The new model can therefore be used as an effective tool to reconstruct peatland palaeohydrology throughout the North American continent. Some eco-regions exhibited lower taxonomic diversity and some key indicator taxa had restricted ranges. However, these patterns occurred against a background of general cosmopolitanism, at the moderate taxonomic resolution used. Likely biogeographical patterns at higher taxonomic resolution therefore do not affect transfer function performance. Output from the combined North American and European model suggested that any geographical limit of scale beyond which further compilation of peatland testate amoeba data would not be valid has not yet been reached, therefore advocating the potential for a Holarctic synthesis of peatland testate amoeba data. Extending data synthesis to the tropics and the Southern Hemisphere would be more challenging due to higher regional endemism in those areas. (C) 2018 The Authors. Published by Elsevier Ltd.