scholarly journals Did a “perfect storm” of oceanic changes and continental anthropogenic impacts cause northern hemisphere anguillid recruitment reductions?

2015 ◽  
Vol 73 (1) ◽  
pp. 43-56 ◽  
Author(s):  
Michael J. Miller ◽  
Eric Feunteun ◽  
Katsumi Tsukamoto
Keyword(s):  
Northern Hemisphere ◽  
Time Window ◽  
Anthropogenic Impacts ◽  
Critical Time ◽  
Larval Survival ◽  
Larval Transport ◽  
Dam Construction ◽  
Marine Snow ◽  
Atmospheric Conditions ◽  
First Feeding

AbstractThe three northern hemisphere anguillid eel species experienced recruitment declines at similar times beginning in the 1970s and 1980s, but the exact causes of the declines have remained unclear. Attention focused on two categories of possible causes that included (i) anthropogenic impacts on eel growth habitats, such as dam construction, degradation and pollution of habitats, introduction of parasites, overfishing and (ii) changes in ocean-atmospheric conditions affecting their marine life-history stages. The cumulative effects of reaching peaks in dam construction, levels of pollution, and eutrophication just before the eel declines likely had reduced eel production in many areas, and contamination by metallic and organic compounds and parasites may have reduced reproductive success. Shifts in ocean-atmospheric conditions also occurred just before the eel declines that could have reduced feeding success of larvae or disrupted larval transport. If oceanic regime shifts reduced production of the marine snow food of eel larvae, it may have affected larval survival and recruitment success, especially if there is a critical time-window for successful larval first feeding when marine snow particles need to be abundant. A reduction of these particles could result in density-dependent early mortality of the larvae of each spawning event, and competition for marine snow particles with sympatrically spawning mesopelagic eel larvae would amplify this effect. Nutrient reductions causing shifts in the relative abundance of phytoplankton contributing to marine snow production and of ubiquitous cyanobacteria may mediate levels of larval survival in areas with high spawning activity. Reductions of eels reaching the spawning area from species range margins that spawn outside of peak spawning periods could have reduced recruitment further. It appears likely that a variety of impacts, oceanic and anthropogenic occurred simultaneously causing sudden declines of these eel populations.

scholarly journals The ecology of oceanic dispersal and survival of anguillid leptocephali

2017 ◽  
Vol 74 (6) ◽  
pp. 958-971 ◽  
Author(s):  
Michael J. Miller ◽  
Katsumi Tsukamoto
Keyword(s):  
Anthropogenic Impacts ◽  
Larval Survival ◽  
Marine Snow ◽  
First Feeding ◽  
Spawning Areas ◽  
Eukaryotic Phytoplankton ◽  
High Nutrient ◽  
Glass Eels ◽  
Predation Rates ◽  
Nutrient Conditions

Recruitment declines of anguillid eels are difficult to understand because both anthropogenic impacts on juveniles and adults and oceanic changes affecting larval survival or dispersal may be contributing. Anguillid larvae may passively disperse widely from offshore spawning areas but late-stage larvae or glass eels apparently must swim directionally to reach recruitment habitats. Their long larval durations vary among tropical (∼3–4 months) and temperate species (5 months to >1 year). The bodies of anguillid leptocephali are filled with transparent gelatinous material, possibly reducing predation rates and providing an energy reserve for swimming and metamorphosis. Leptocephali feed on marine snow making their first-feeding success linked to primary producers contributing to marine snow production. Alternations between ubiquitous cyanobacteria dominating in low-nutrient conditions and eukaryotic phytoplankton such as diatoms that are important for marine snow production dominating in high-nutrient conditions may influence early-larval survival at first-feeding due to many eggs simultaneously hatching within sympatric spawning areas. Fewer spawning eels resulting from population reductions and variations in early-larval survival may offer some explanations for lower and fluctuating recruitment in recent decades.

scholarly journals Global source attribution of sulfate concentration and direct and indirect radiative forcing

2017 ◽  
Vol 17 (14) ◽  
pp. 8903-8922 ◽  
Author(s):  
Yang Yang ◽  
Hailong Wang ◽  
Steven J. Smith ◽  
Richard Easter ◽  
Po-Lun Ma ◽  
...  
Keyword(s):  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Radiative Forcing ◽  
Dimethyl Sulfide ◽  
Sulfur Source ◽  
Atmospheric Conditions ◽  
So2 Emissions ◽  
Near Surface ◽  
Indirect Radiative Forcing ◽  
Global Source

Abstract. The global source–receptor relationships of sulfate concentrations, and direct and indirect radiative forcing (DRF and IRF) from 16 regions/sectors for years 2010–2014 are examined in this study through utilizing a sulfur source-tagging capability implemented in the Community Earth System Model (CESM) with winds nudged to reanalysis data. Sulfate concentrations are mostly contributed by local emissions in regions with high emissions, while over regions with relatively low SO2 emissions, the near-surface sulfate concentrations are primarily attributed to non-local sources from long-range transport. Regional source efficiencies of sulfate concentrations are higher over regions with dry atmospheric conditions and less export, suggesting that lifetime of aerosols, together with regional export, is important in determining regional air quality. The simulated global total sulfate DRF is −0.42 W m−2, with −0.31 W m−2 contributed by anthropogenic sulfate and −0.11 W m−2 contributed by natural sulfate, relative to a state with no sulfur emissions. In the Southern Hemisphere tropics, dimethyl sulfide (DMS) contributes 17–84 % to the total DRF. East Asia has the largest contribution of 20–30 % over the Northern Hemisphere mid- and high latitudes. A 20 % perturbation of sulfate and its precursor emissions gives a sulfate incremental IRF of −0.44 W m−2. DMS has the largest contribution, explaining −0.23 W m−2 of the global sulfate incremental IRF. Incremental IRF over regions in the Southern Hemisphere with low background aerosols is more sensitive to emission perturbation than that over the polluted Northern Hemisphere.

scholarly journals Anthropogenic impacts on Keshalia River, Eastern Nepal

2017 ◽  
Vol 7 (1) ◽  
pp. 105-111
Author(s):  
Jay Narayan Shrestha
Keyword(s):  
Anthropogenic Impact ◽  
Anthropogenic Impacts ◽  
Industrial Effluents ◽  
Fish Diversity ◽  
Dam Construction ◽  
Fish Ladder ◽  
Very High

The anthropogenic impact on Keshalia river, especially on fish diversity, is very high. Over fishing with unconventional fishing methods, disposal of domestic and industrial effluents, excess use of pesticides, dumping sites of municipalities, dam construction without fish ladder across the river and mining of sands and gravels are major anthropogenic impacts on the river.

scholarly journals Time-Varying Associations Between an Exposure History and a Subsequent Health Outcome: A landmark Approach to Identify Critical Windows.

2021 ◽  
Author(s):  
Maude Wagner ◽  
Francine Grodstein ◽  
Karen Leffondre ◽  
Cécilia Samieri ◽  
Cécile Proust-Lima
Keyword(s):  
Risk Factors ◽  
Health Outcome ◽  
Measurement Errors ◽  
Mixed Model ◽  
Time Window ◽  
Time Windows ◽  
Critical Time ◽  
Cumulative Exposure ◽  
Exposure Measurement ◽  
Exposure History

Abstract Background: Long-term behavioral and health risk factors constitute a primary focus of research on the etiology of chronic diseases. Yet, identifying critical time-windows during which risk factors have the strongest impact on disease risk is challenging. To assess the trajectory of association of an exposure history with an outcome, the weighted cumulative exposure index (WCIE) has been proposed, with weights reflecting the relative importance of exposures at different times. However, WCIE is restricted to a complete observed error-free exposure whereas exposures are often measured with intermittent missingness and error. Moreover, it rarely explores exposure history that is very distant from the outcome as usually sought in life-course epidemiology.Methods: We extend the WCIE methodology to (i) exposures that are intermittently measured with error, and (ii) contexts where the exposure time-window precedes the outcome time-window using a landmark approach. First, the individual exposure history up to the landmark time is estimated using a mixed model that handles missing data and error in exposure measurement, and the predicted complete error-free exposure history is derived. Then the WCIE methodology is applied to assess the trajectory of association between the predicted exposure history and the health outcome collected after the landmark time. In our context, the health outcome is a longitudinal marker analyzed using a mixed model.Results: A simulation study first demonstrates the correct inference obtained with this approach. Then, applied to the Nurses’ Health Study (19,415 women) to investigate the association between body mass index history (collected from midlife) and subsequent cognitive decline (evaluated after age 70), the method identified two major critical windows of association: long before the first cognitive evaluation (roughly 24 to 12 years), higher levels of BMI were associated with poorer cognition. In contrast, adjusted for the whole history, higher levels of BMI became associated with better cognition in the last years prior to the first cognitive interview, thus reflecting reverse causation (changes in exposure due to underlying disease).Conclusions: This approach, easy to implement, provides a flexible tool for studying complex dynamic relationships and identifying critical time windows while accounting for exposure measurement errors.

scholarly journals How Predictable Are the Arctic and North Atlantic Oscillations? Exploring the Variability and Predictability of the Northern Hemisphere

2018 ◽  
Vol 31 (3) ◽  
pp. 997-1014 ◽  
Author(s):  
Daniela I. V. Domeisen ◽  
Gualtiero Badin ◽  
Inga M. Koszalka
Keyword(s):  
Time Scales ◽  
Northern Hemisphere ◽  
North Atlantic ◽  
Prediction Models ◽  
The Arctic ◽  
Ensemble Prediction ◽  
Atmospheric Conditions ◽  
Short Term ◽  
The North ◽  
The North Atlantic Oscillation

ABSTRACT The North Atlantic Oscillation (NAO) and the Arctic Oscillation (AO) describe the dominant part of the variability in the Northern Hemisphere extratropical troposphere. Because of the strong connection of these patterns with surface climate, recent years have shown an increased interest and an increasing skill in forecasting them. However, it is unclear what the intrinsic limits of short-term predictability for the NAO and AO patterns are. This study compares the variability and predictability of both patterns, using a range of data and index computation methods for the daily NAO and AO indices. Small deviations from Gaussianity are found along with characteristic decorrelation time scales of around one week. In the analysis of the Lyapunov spectrum it is found that predictability is not significantly different between the AO and NAO or between reanalysis products. Differences exist, however, between the indices based on EOF analysis, which exhibit predictability time scales around 12–16 days, and the station-based indices, exhibiting a longer predictability of 18–20 days. Both of these time scales indicate predictability beyond that currently obtained in ensemble prediction models for short-term predictability. Additional longer-term predictability for these patterns may be gained through local feedbacks and remote forcing mechanisms for particular atmospheric conditions.

scholarly journals Clinical Evaluation of Herbal Medicine (ICH-012) in Treating Acute Cerebral Haemorrhage: Safety and Efficacy from 6- to 72-Hour Time Window (CRRICHTrial-II)

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Qixin Zhang ◽  
Liling Zeng ◽  
Xiuyan Chen ◽  
Yuexiang Zhou ◽  
Baoying Gong ◽  
...  
Keyword(s):  
Herbal Medicine ◽  
Ct Scan ◽  
Time Window ◽  
Rapid Change ◽  
Herbal Medicines ◽  
Critical Time ◽  
Cerebral Haemorrhage ◽  
High Morbidity ◽  
Safety And Efficacy ◽  
Link Type

Background. Hypertensive intracerebral haemorrhage (HICH), which is characterized by rapid change, high morbidity, and mortality, is extremely dangerous. Both medical and surgical treatments lack definitive evidence and remain controversial. A prospective RCT that we have conducted has shown that the usage of the herbal medicine ICH-012 within 6 h of the event may increase the risk of haematoma enlargement and gastrointestinal bleeding. However, the volume of haematoma remains stable after 6 h. Thus, we will increase the time window to the period from 6 to 72 h after onset to evaluate the safety and efficacy of ICH-012 treating ICH (ClinicalTrial.gov ID: NCT03354026). Methods/Design. The CRRICHTrial-II study, a prospective, double-blinded, controlled, multicentre RCT, includes three groups: A, B, and C. Group A patients were treated with 8 herbal medicines (with 2 herbal medicines of Hirudo and Tabanus as well as 6 other combined herbal medicines of Group B) and Group C were placebo. Patients should meet all the inclusion criteria: age between 18 and 80 and diagnosis of HICH by brain CT scan between 6 and 72 h from the onset. The CT scan will be taken at four critical time points: baseline, between 6 and 72h, 24h after onset, and between 10 and 14 days after onset. The drug intervention lasts 10 days, and there is a follow-up visit taken after 90 days. The haematoma enlargement after 24 h onset as demonstrated by CT is the primary outcome. Discussion. A large amount of data from high-quality RCTs is needed for the extensive clinical application of herbal medicine. The CRRICHTrial-II will evaluate the safety and effectiveness of ICH-012 in a safer time window between 6 and 72 h and investigate the possible mechanisms of action and direction of herbal medicine in the haematoma growth after HICH. Trial registration at ClinicalTrial.gov, ID: NCT03354026, is registered on 23rd Nov. 2017.

Right-time vs real-time pro-active construction safety and health system architecture

2016 ◽  
Vol 16 (3) ◽  
pp. 253-280 ◽  
Author(s):  
Jochen Teizer
Keyword(s):  
Supply Chain ◽  
Real Time ◽  
Occupational Safety ◽  
Time Window ◽  
Data Gathering ◽  
Critical Time ◽  
Construction Safety ◽  
Content Type ◽  
Safety And Health ◽  
High Concern

Purpose The purpose of this paper is to investigate the critical time window for pro-active construction accident prevention and response. Large to small organisations throughout the entire construction supply chain continue to be challenged to adequately prevent accidents. Construction worker injuries and fatalities represent significant waste of resources. Although the five C’s (culture, competency, communication, controls and contractors) have been focusing on compliance, good practices and best-in-class strategies, even industry leaders have only marginal improvements in recorded safety statistics for many years. Design/methodology/approach Right-time vs real-time construction safety and health identifies three major focus areas to aid in the development of a strategic, as opposed to tactical, response. Occupational safety and health by design, real-time safety and health monitoring and alerts and education, training and feedback leveraging state-of-the-art technology provide meaningful predictive, quantitative and qualitative measures to identify, correlate and eliminate hazards before workers get injured or incidents cause collateral damage. Findings The current state and development of existing innovative initiatives in the occupational construction safety and health domain are identified. A framework for right-time vs real-time construction safety and health presents the specific focus on automated safety and health data gathering, analysis and reporting to achieve better safety performance. The developed roadmap for right-time vs real-time safety and health is finally tested in selected application scenarios of high concern in the construction industry. Originality/value A strategic roadmap to eliminate hazards and accidents through right-time vs real-time automation is presented that has practical as well as social implications on conducting a rigorous safety culture and climate in a construction business and its entire supply chain.

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