69 research outputs found
Prioritizing the protection of climate refugia: designing a climate-ready protected area network
Protected areas are the primary strategy for maintaining natural landscapes and separating biodiversity features from preventable anthropogenic threats. The Convention on Biological Diversity calls for the coverage of at least 17% of land by protected areas, and the strategic prioritization of important biodiversity areas. Using the spatially explicit reserve design software, Marxan, this study combines climate refugia modelled under future climates in the year 2070 and bioregions to identify priority sites for protected area expansion under climate change in the state of New South Wales (NSW), Australia. Priority sites for new protected areas that meet bioregion and climate refugia targets were identified in central-western, northeast and patches of southeast NSW. Seven existing parks, including Kosciuszko National Park, overlapped with regions identified repeatedly as climate refugia under 12 future climate scenarios. The recommendations from this study support policy-makers in prioritizing the protection of biodiversity under a changing and uncertain climate
A feasibility study on the implementation of visibility algorithms for fault diagnosis in aircraft fuel systems
This paper discusses the applicability of Visibility Algorithms to detect faults in condition monitoring applications. The general purpose of Visibility Algorithms is to transform time series into graphs and study them through the characterisation of their associated network. Degradation of a component results in changes to the network. This technique has been applied using a test rig of an aircraft fuel system to show that there is a correlation between the values of key metrics of visibility graphs and the severity of four failure modes. We compare the results of using Horizontal Visibility algorithms against Natural Visibility algorithms. The results also show how the Kullback-Leibler divergence and statistical entropy can be used to produce condition indicators. Experimental results show that there is little dispersion in the values of condition indicators, leading to a low probability of false positives and false negatives
(Re)designing urban parks to maximize urban heat island mitigation by natural means
Urban trees play a key role in mitigating urban heat by cooling the local environment. However, the cooling benefit that trees can provide is influenced by differences in species traits and site-specific environmental conditions. Fifteen dominant urban tree species in parks from Mexico City were selected considering physiological traits (i.e., transpiration and stomatal conductance) and aesthetic and morphological characteristics. Speciesâ physiological performance was measured to explore the potential of trees to reduce urban heat load. Data were collected over a 4-week period in the months of April and May 2020, the warmest and driest months of the year in Mexico City. We used the Thermal UrbaN Environment Energy (TUNEE) balance model to calculate the cooling benefit of each species and the number of individuals necessary to reduce local air temperature. The highest midday transpiration was registered for Liquidambar styraciflua L. (0.0357 g mâ2 sâ1) and the lowest for Buddleja cordata H.B.K (0.0089 g mâ2 sâ1), representing an energy consumption and cooling potential of 87.13 and 21.69 J mâ2 sâ1, respectively. Similarly, the highest stomatal conductance was recorded for L. styraciflua., whereas the lowest was recorded for B. cordata. Based on the species transpiration rates and aesthetic characteristics, we developed a proposal and outline for a 50 X 50 m urban park (i.e., park community) consisting of six species with 19 individuals, and according to the TUNEE model, the proposed arrangement can reduce air temperature up to 5.3 °C. Our results can help urban planners to (re)design urban parks to mitigate urban heat while increasing urban tree diversity in parks
How important are fog and the cloud forest as a water supply in Eastern Mexico?
The water balance is the volume of water flowing through the hydrological cycle, and one of its main components is fog. Fog is considered a type of low-lying cloud and is heavily influenced by water bodies, topography, and wind conditions. Fog incorporates water from the atmosphere to the terrestrial surface and for some ecosystems (e.g., cloud forests) represents a great water contribution. In this work, we aimed to answer the following questions: (1) What is the fog-water contribution to the water balance? (2) How does the presence of vegetation affect the water supply to the ecosystem? We took as a case study the Central Mountain Region of Veracruz, in eastern Mexico, and measured components of the water balance; this included precipitation (gross and net), fog water, interception, transpiration, evapotranspiration, and condensation, and we estimated water gain and loss of the water balance. We registered 510 precipitation events distributed throughout the year with three peaks (October, May, and January). Of these, 386 were fog events, 41 were rain events, and 83 were events combining fog and rain. Fog had a substantial contribution of water to the system, with a volume 22 times greater than that of rain (4311.14 mm vs. 197.5 mm). From the total water gain, the highest proportion (91%) was contributed by fog interception. Fog was considered a constant source of moisture throughout the year; however, water intercepted during the dry season was higher (56%) compared with the wet season (36%). Our results highlight the importance of the fog as a source of water for the region
Climate change threatens the most biodiverse regions of Mexico
International audienceClimate change threatens Earth's biodiversity, although its impacts are variable and depend on the capacity of species and ecosystems to cope with the magnitude and speed of change. Natural protected areas (NPAs) constitute potential refugia for species' persistence and for sustaining the provisioning of ecosystem services. Biosphere reserves are NPAs that are less altered by human actions and provide habitat to endemic, threatened or endangered species. Here, we aim to evaluate the threat imposed by climate change on the network of biosphere reserves in Mexico. Focusing on five bioclimatic variables, we computed the climatic space â measured as an n-dimensional hypervolume â of 40 NPAs. Increases in temperature are predicted for all NPAs by 2050, whereas decreases in annual rainfall are predicted for 30 NPAs. By 2050, 31 NPAs that provide habitat to 22,866 recorded species are predicted to lose 100% of their baseline climatic space, shifting to completely novel climates. On average, the other nine NPAs are predicted to lose 55.7% (SD = 26.7%) of their baseline climatic space, while 54.5% (SD = 32.5%) of the future climatic space will be novel. Seventeen NPAs may lose climate variability (homogenization), decreasing species' niches. The extent to which non-analogue conditions will remain within the tolerance of species and ecosystems is currently unknown. Finally, we propose a vulnerability index to categorise NPAs based on their loss of existing climatic space, total geographic area, species richness, and uniqueness of species composition, finding los Tuxtlas and Tiburon Ballena as the most and least vulnerable NPAs, respectively
Tree traits and microclimatic conditions determine cooling benefits of urban trees
Trees play a key role in mitigating urban heat by cooling the local environment. This study evaluated the extent to which street trees can reduce sub-canopy air temperature relative to ambient conditions (DT), and how DT relates to tree traits and microclimatic variables. Air temperature under the canopies of 10 species was recorded within residential areas in Western Sydney, Australia, during summer 2019â2020. Tree and canopy traits, namely tree height, specific leaf area, leaf dry matter content, leaf area index, crown width and the Huber value (the ratio of sapwood area to leaf area) were then measured for all species. Species differed significantly in their DT values, with peak cooling (maximum DT 3.9 C) observed between 9â10 am and sub-canopy warming (i.e., positive DT values) typically occurring during afternoon and overnight. Trees with high LAI and wider canopies were associated with the greatest daytime cooling benefits and lower levels of nighttime warming. DT was also negatively related to windspeed and vapor pressure deficit, and positively to solar irradiance. This study provides valuable information on how tree characteristics and microclimate influence potential cooling benefits that may aid planning decisions on the use of trees to mitigate heat in urban landscapes
Assessing climate risk to support urban forests in a changing climate
We thank Leslie Brandt and Gregory McPherson (USDA Forest Service,
USA), Jakub Kronenberg (University of Lodz, Poland), Shawn
Landry (University of South Florida, USA) and Per Anker Pedersen
(Faculty of Landscape and Society, Norwegian University of Life Sciences)
for their thoughts and contributions. MER, PR, SP and MGT
thank Leigh Staas (Macquarie University) and funding from the Hort
Frontiers Green Cities Fund, part of the Hort Frontiers strategic partnership initiative developed by Hort Innovation, with coinvestment
from Macquarie University, Western Sydney University
and the NSW Department of Planning, Industry and Environment and
contributions from the Australian Government. DNB acknowledges
support from the Research Council of Norway to the ENABLE project
through the BiodivERsA COFUND 2015-2016 call for research proposals.
BW acknowledges support from FORMAS (dia.nr
2016-20098). Finally, we thank the anonymous reviewers for their
critical observations and thoughtful contributions that improved this
work. The opinions and findings expressed in this paper are those of
the authors and should not be construed to represent any official
USDA or US Government determination or policy.Societal Impact Statement
Globally, cities are planning for resilience through urban greening initiatives as governments
understand the importance of urban forests in improving quality of life
and mitigating climate change. However, the persistence of urban forests and the
ecosystem benefits they provide are threatened by climate change, and systematic
assessments of causes of tree dieback and mortality in urban environments are rare.
Long-term monitoring studies and adaptive management are needed to identify and
prevent climate change-driven failures and mortality. Research and monitoring
when coupled with systematic forecasting will enable governments to incorporate
climate change resilience into urban forestry planning. Future scenarios in which
urban forests are resilient or in decline will depend on the management and
planning actions we make today.The management of urban forests is a key element of resilience planning in cities across the globe. Urban forests provide ecosystem services as well as other nature-based solutions to 4.2 billion people living in cities. However, to continue to do so effectively, urban forests need to be able to thrive in an increasingly changing climate. Trees in cities are vulnerable to extreme heat and drought events, which are predicted to increase in frequency and severity under climate change. Knowledge of species' vulnerability to climate change, therefore, is crucial to ensure provision of desired ecosystem benefits, improve species selection, maintain tree growth and reduce tree mortality, dieback and stress in urban forests. Yet, systematic assessments of causes of tree dieback and mortality in urban environments are rare. We reviewed the state of knowledge of tree mortality in urban forests globally, finding very few frameworks that enable detection of climate change impacts on urban forests and no long-term studies assessing climate change as a direct driver of urban tree dieback and mortality. The effects of climate change on urban forests remain poorly understood and quantified, constraining the ability of governments to incorporate climate change resilience into urban forestry planning.Hort Frontiers Green Cities Fund, Hort Frontiers strategic partnership initiativeResearch Council of NorwaySwedish Research Council Formas
2016-2009
The Changing Landscape for Stroke\ua0Prevention in AF: Findings From the GLORIA-AF Registry Phase 2
Background GLORIA-AF (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation) is a prospective, global registry program describing antithrombotic treatment patterns in patients with newly diagnosed nonvalvular atrial fibrillation at risk of stroke. Phase 2 began when dabigatran, the first non\u2013vitamin K antagonist oral anticoagulant (NOAC), became available. Objectives This study sought to describe phase 2 baseline data and compare these with the pre-NOAC era collected during phase 1. Methods During phase 2, 15,641 consenting patients were enrolled (November 2011 to December 2014); 15,092 were eligible. This pre-specified cross-sectional analysis describes eligible patients\u2019 baseline characteristics. Atrial fibrillation disease characteristics, medical outcomes, and concomitant diseases and medications were collected. Data were analyzed using descriptive statistics. Results Of the total patients, 45.5% were female; median age was 71 (interquartile range: 64, 78) years. Patients were from Europe (47.1%), North America (22.5%), Asia (20.3%), Latin America (6.0%), and the Middle East/Africa (4.0%). Most had high stroke risk (CHA2DS2-VASc [Congestive heart failure, Hypertension, Age 6575 years, Diabetes mellitus, previous Stroke, Vascular disease, Age 65 to 74 years, Sex category] score 652; 86.1%); 13.9% had moderate risk (CHA2DS2-VASc = 1). Overall, 79.9% received oral anticoagulants, of whom 47.6% received NOAC and 32.3% vitamin K antagonists (VKA); 12.1% received antiplatelet agents; 7.8% received no antithrombotic treatment. For comparison, the proportion of phase 1 patients (of N = 1,063 all eligible) prescribed VKA was 32.8%, acetylsalicylic acid 41.7%, and no therapy 20.2%. In Europe in phase 2, treatment with NOAC was more common than VKA (52.3% and 37.8%, respectively); 6.0% of patients received antiplatelet treatment; and 3.8% received no antithrombotic treatment. In North America, 52.1%, 26.2%, and 14.0% of patients received NOAC, VKA, and antiplatelet drugs, respectively; 7.5% received no antithrombotic treatment. NOAC use was less common in Asia (27.7%), where 27.5% of patients received VKA, 25.0% antiplatelet drugs, and 19.8% no antithrombotic treatment. Conclusions The baseline data from GLORIA-AF phase 2 demonstrate that in newly diagnosed nonvalvular atrial fibrillation patients, NOAC have been highly adopted into practice, becoming more frequently prescribed than VKA in Europe and North America. Worldwide, however, a large proportion of patients remain undertreated, particularly in Asia and North America. (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients With Atrial Fibrillation [GLORIA-AF]; NCT01468701
Omecamtiv mecarbil in chronic heart failure with reduced ejection fraction, GALACTICâHF: baseline characteristics and comparison with contemporary clinical trials
Aims:
The safety and efficacy of the novel selective cardiac myosin activator, omecamtiv mecarbil, in patients with heart failure with reduced ejection fraction (HFrEF) is tested in the Global Approach to Lowering Adverse Cardiac outcomes Through Improving Contractility in Heart Failure (GALACTICâHF) trial. Here we describe the baseline characteristics of participants in GALACTICâHF and how these compare with other contemporary trials.
Methods and Results:
Adults with established HFrEF, New York Heart Association functional class (NYHA)ââ„âII, EF â€35%, elevated natriuretic peptides and either current hospitalization for HF or history of hospitalization/ emergency department visit for HF within a year were randomized to either placebo or omecamtiv mecarbil (pharmacokineticâguided dosing: 25, 37.5 or 50âmg bid). 8256 patients [male (79%), nonâwhite (22%), mean age 65âyears] were enrolled with a mean EF 27%, ischemic etiology in 54%, NYHA II 53% and III/IV 47%, and median NTâproBNP 1971âpg/mL. HF therapies at baseline were among the most effectively employed in contemporary HF trials. GALACTICâHF randomized patients representative of recent HF registries and trials with substantial numbers of patients also having characteristics understudied in previous trials including more from North America (n = 1386), enrolled as inpatients (n = 2084), systolic blood pressureâ<â100âmmHg (n = 1127), estimated glomerular filtration rate <â30âmL/min/1.73 m2 (n = 528), and treated with sacubitrilâvalsartan at baseline (n = 1594).
Conclusions:
GALACTICâHF enrolled a wellâtreated, highârisk population from both inpatient and outpatient settings, which will provide a definitive evaluation of the efficacy and safety of this novel therapy, as well as informing its potential future implementation
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