A Phased Approach for Assessing Combined Effects from Multiple Stressors

We present a phased approach for evaluating the effects of physical, biological, chemical, and psychosocial stressors that may act in combination. Although a phased concept is common to many risk-based approaches, it has not been explicitly outlined for the assessment of combined effects of multiple stressors. The approach begins with the development of appropriate conceptual models and assessment end points. The approach then proceeds through a screening stage wherein stressors are evaluated with respect to their potential importance as contributors to risk. Stressors are considered individually or as a combination of independent factors with respect to one or more common assessment end points. As necessary, the approach then proceeds to consider interactions among stressors. We make a distinction between applications that begin with effects of concern (effects based) or with specific stressors (stressor based). We describe a number of tools for use within the phased approach. The methods profiled are ones that have been applied to yield results that can be communicated to a wide audience. The latter characteristic is considered especially important because multiple stressor problems usually involve exposures to communities or to ecologic regions with many stakeholders

Passive sampling methods for contaminated sediments: Risk assessment and management

This paper details how activity-based passive sampling methods (PSMs), which provide information on bioavailability in terms of freely dissolved contaminant concentrations (Cfree), can be used to better inform risk management decision making at multiple points in the process of assessing and managing contaminated sediment sites. PSMs can increase certainty in site investigation and management, because Cfree is a better predictor of bioavailability than total bulk sediment concentration (Ctotal) for 4 key endpoints included in conceptual site models (benthic organism toxicity, bioaccumulation, sediment flux, and water column exposures). The use of passive sampling devices (PSDs) presents challenges with respect to representative sampling for estimating average concentrations and other metrics relevant for exposure and risk assessment. These challenges can be addressed by designing studies that account for sources of variation associated with PSMs and considering appropriate spatial scales to meet study objectives. Possible applications of PSMs include: quantifying spatial and temporal trends in bioavailable contaminants, identifying and evaluating contaminant source contributions, calibrating site-specific models, and, improving weight-of-evidence based decision frameworks. PSM data can be used to assist in delineating sediment management zones based on likelihood of exposure effects, monitor remedy effectiveness, and, evaluate risk reduction after sediment treatment, disposal, or beneficial reuse after management actions. Examples are provided illustrating why PSMs and freely dissolved contaminant concentrations (Cfree) should be incorporated into contaminated sediment investigations and study designs to better focus on and understand contaminant bioavailability, more accurately estimate exposure to sediment-associated contaminants, and better inform risk management decisions. Research and communication needs for encouraging broader use are discussed. Integr Environ Assess Manag 2014;10:224–236. © 2014 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of SETAC

First detection of two superoutbursts during rebrightening phase of a WZ Sge-type Dwarf Nova : TCP J21040470+4631129

We report on photometric and spectroscopic observations and analysis of the 2019 superoutburst of TCP J21040470+4631129. This object showed a 9 mag superoutburst with early superhumps and ordinary superhumps, which are the features of WZ Sge-type dwarf novae. Five rebrightenings were observed after the main superoutburst. The spectra during the post-superoutburst stage showed Balmer, He I, and possible sodium doublet features. The mass ratio is derived as 0.0880(9) from the period of the superhump. During the third and fifth rebrightenings, growing superhumps and superoutbursts were observed, which have never been detected during a rebrightening phase among WZ Sge-type dwarf novae with multiple rebrightenings. To induce a superoutburst during the brightening phase, the accretion disk needs to have expanded beyond the 3 : 1 resonance radius of the system again after the main superoutburst. These peculiar phenomena can be explained by the enhanced viscosity and large radius of the accretion disk suggested by the higher luminosity and the presence of late-stage superhumps during the post-superoutburst stage, plus by more mass supply from the cool mass reservoir and/or from the secondary because of the enhanced mass transfer than those of other WZ Sge-type dwarf novae.peer-reviewe

Permanent and Selective Capital Account Management Regimes as an Alternative to Self-Insurance Strategies in Emerging-Market Economies

Currency market intervention-cum-reserve accumulation has emerged as the favored selfinsurance strategy in recipient countries of excessive private capital inflows. This paper argues that capital account management represents a less costly alternative line of defense deserving renewed consideration, especially in the absence of fundamental reform of the global monetary and financial order. Mainstream arguments in favor of financial globalization are found unconvincing; any indirect benefits allegedly obtainable through hot money inflows are equally obtainable without actually tolerating such inflows. The paper investigates the experiences of Brazil, Russia, India, and China (the BRICs) in the global crisis and subsequent recovery, focusing on their respective policies regarding capital flows

Trade Imbalances and Multilateral Trade Cooperation

Rising current account and merchandise trade imbalances marked the years before the global financial and economic crisis. These imbalances either contributed to or precipitated the crisis and to the extent that they create systemic risks, it is desirable that they be reduced. There are many factors related to macroeconomic, structural, exchange rate and financial policies that contributed to the imbalances. The inability to manage these issues at the international level reflects the coherence gap in global governance. This paper examines the contribution that the WTO can make in its three areas of activities - negotiations, rule-making and dispute settlement - to deal with trade imbalances and with the main factors leading to them, including exchange rate misalignments. First, market opening efforts in services, including in the area of financial services, can reduce policy-related distortions and market imperfections in surplus countries that lead to the build-up of unsustainable imbalances. Second, in the context of a broad international effort to coordinate macroeconomic, exchange rate and structural policies to deal with the roots of imbalances (the first-best solution), there is a general efficiency argument that could be made for the use of WTO-triggered trade actions to enforce cooperative behaviour towards rebalancing. Absent this first-best response, trade rules alone would not provide an efficient instrument to compensate for the weaknesses in international co-operation in macroeconomic, exchange rate and structural policies

and temporal scales

Defining populations: a key step in identifying spatia