C++ Standard Template Library by template specialized containers

The C++ Standard Template Library is the flagship example for libraries based on the generic programming paradigm. The usage of this library is intended to minimize the number of classical C/C++ errors, but does not warrant bug-free programs. Furthermore, many new kinds of errors may arise from the inaccurate use of the generic programming paradigm, like dereferencing invalid iterators or misunderstanding remove-like algorithms. In this paper we present some typical scenarios that may cause runtime or portability problems. We emit warnings and errors while these risky constructs are used. We also present a general approach to emit "customized" warnings. We support the so-called "believe-me marks" to disable warnings. We present another typical usage of our technique, when classes become deprecated during the software lifecycle

Characterizing the universal rigidity of generic frameworks

A framework is a graph and a map from its vertices to E^d (for some d). A framework is universally rigid if any framework in any dimension with the same graph and edge lengths is a Euclidean image of it. We show that a generic universally rigid framework has a positive semi-definite stress matrix of maximal rank. Connelly showed that the existence of such a positive semi-definite stress matrix is sufficient for universal rigidity, so this provides a characterization of universal rigidity for generic frameworks. We also extend our argument to give a new result on the genericity of strict complementarity in semidefinite programming.Comment: 18 pages, v2: updates throughout; v3: published versio

Convergent Surface Water Distributions in U.S. Cities

Earth's surface is rapidly urbanizing, resulting in dramatic changes in the abundance, distribution and character of surface water features in urban landscapes. However, the scope and consequences of surface water redistribution at broad spatial scales are not well understood. We hypothesized that urbanization would lead to convergent surface water abundance and distribution: in other words, cities will gain or lose water such that they become more similar to each other than are their surrounding natural landscapes. Using a database of more than 1 million water bodies and 1 million km of streams, we compared the surface water of 100 US cities with their surrounding undeveloped land. We evaluated differences in areal (A WB) and numeric densities (N WB) of water bodies (lakes, wetlands, and so on), the morphological characteristics of water bodies (size), and the density (D C) of surface flow channels (that is, streams and rivers). The variance of urban A WB, N WB, and D C across the 100 MSAs decreased, by 89, 25, and 71%, respectively, compared to undeveloped land. These data show that many cities are surface water poor relative to undeveloped land; however, in drier landscapes urbanization increases the occurrence of surface water. This convergence pattern strengthened with development intensity, such that high intensity urban development had an areal water body density 98% less than undeveloped lands. Urbanization appears to drive the convergence of hydrological features across the US, such that surface water distributions of cities are more similar to each other than to their surrounding landscapes. © 2014 The Author(s)

Assessing the homogenization of urban land management with an application to US residential lawn care.

Changes in land use, land cover, and land management present some of the greatest potential global environmental challenges of the 21st century. Urbanization, one of the principal drivers of these transformations, is commonly thought to be generating land changes that are increasingly similar. An implication of this multiscale homogenization hypothesis is that the ecosystem structure and function and human behaviors associated with urbanization should be more similar in certain kinds of urbanized locations across biogeophysical gradients than across urbanization gradients in places with similar biogeophysical characteristics. This paper introduces an analytical framework for testing this hypothesis, and applies the framework to the case of residential lawn care. This set of land management behaviors are often assumed--not demonstrated--to exhibit homogeneity. Multivariate analyses are conducted on telephone survey responses from a geographically stratified random sample of homeowners (n = 9,480), equally distributed across six US metropolitan areas. Two behaviors are examined: lawn fertilizing and irrigating. Limited support for strong homogenization is found at two scales (i.e., multi- and single-city; 2 of 36 cases), but significant support is found for homogenization at only one scale (22 cases) or at neither scale (12 cases). These results suggest that US lawn care behaviors are more differentiated in practice than in theory. Thus, even if the biophysical outcomes of urbanization are homogenizing, managing the associated sustainability implications may require a multiscale, differentiated approach because the underlying social practices appear relatively varied. The analytical approach introduced here should also be productive for other facets of urban-ecological homogenization

Accelerating surveillance and research of antimicrobial resistance - an online repository for sharing of antimicrobial susceptibility data associated with whole-genome sequences

Antimicrobial resistance (AMR) is an emerging threat to modern medicine. Improved diagnostics and surveillance of resistant bacteria require the development of next-generation analysis tools and collabor

Recognizing and modeling variable drawdown due to evapotranspiration in a semiarid riparian zone considering local differences in vegetation and distance from a river source

Riparian zones in semiarid regions often exhibit high rates of evapotranspiration (ET) in spite of low-soil moisture content due to the presence of phreatophytic vegetation that is able to withdraw water from shallow aquifers. This work seeks to better define the relationship between ET, the saturated zone and the river boundary by comparing observed water table drawdown records to analytically modeled drawdown in fully penetrating wells of an unconfined aquifer in response to daily ET flux. ET at the Boise Hydrogeophysical Research Site (BHRS), a riparian zone in a temperate, semiarid environment, is calculated using a radiation-based method to provide ET values at four different wells with different vegetation densities. Analytically modeled drawdown response to ET forcing shows that drawdown magnitude increases with increasing distance from the river edge even as the surficial ET forcing remains constant. This behavior is also observed in well hydrographs and shows the buffering effect that flow from the river has on drawdown in fully penetrating riparian wells in highly permeable, unconfined aquifers. Relative contributions of river water to aquifer storage are calculated for ET-induced diurnal fluctuations of the water table at increasing distances from the river boundary. Failure to account for these spatial differences in drawdown related to the river source may explain some errors associated with estimating ET from well hydrographs alone

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