scholarly journals Woody Plant Encroachment and the Sustainability of Priority Conservation Areas

2020 ◽  
Vol 12 (20) ◽  
pp. 8321
Author(s):  
Dillon T. Fogarty ◽  
Caleb P. Roberts ◽  
Daniel R. Uden ◽  
Victoria M. Donovan ◽  
Craig R. Allen ◽  
...  
Keyword(s):  
Large Scale ◽  
Woody Plant ◽  
Control Strategies ◽  
Action Plan ◽  
Woody Encroachment ◽  
Conservation Practices ◽  
Conservation Areas ◽  
Grassland Conservation ◽  
Proactive Management ◽  
Woody Cover

Woody encroachment is a global driver of grassland loss and management to counteract encroachment represents one of the most expensive conservation practices implemented in grasslands. Yet, outcomes of these practices are often unknown at large scales and this constrains practitioner’s ability to advance conservation. Here, we use new monitoring data to evaluate outcomes of grassland conservation on woody encroachment for Nebraska’s State Wildlife Action Plan, a statewide effort that targets management in Biologically Unique Landscapes (BULs) to conserve the state’s natural communities. We tracked woody cover trajectories for BULs and compared BUL trajectories with those in non-priority landscapes (non-BULs) to evaluate statewide and BUL-scale conservation outcomes more than a decade after BUL establishment. Statewide, woody cover increased by 256,653 ha (2.3%) from 2000–2017. Most BULs (71%) experienced unsustainable trends of grassland loss to woody encroachment; however, management appeared to significantly reduce BUL encroachment rates compared to non-BULs. Most BULs with early signs of encroachment lacked control strategies, while only one BUL with moderate levels of encroachment (Loess Canyons) showed evidence of a management-driven stabilization of encroachment. These results identify strategic opportunities for proactive management in grassland conservation and demonstrate how new monitoring technology can support large-scale adaptive management pursuits.

scholarly journals Woody encroachment over 70 years in South African savannahs: overgrazing, global change or extinction aftershock?

2016 ◽  
Vol 371 (1703) ◽  
pp. 20150437 ◽  
Author(s):  
Nicola Stevens ◽  
B. F. N. Erasmus ◽  
S. Archibald ◽  
W. J. Bond
Keyword(s):  
Land Use ◽  
South African ◽  
Woody Encroachment ◽  
Land Uses ◽  
Conservation Areas ◽  
Rainfall Gradient ◽  
Object Based Image Analysis ◽  
Global Factor ◽  
Object Based ◽  
Woody Cover

Woody encroachment in ‘open’ biomes like grasslands and savannahs is occurring globally. Both local and global drivers, including elevated CO 2 , have been implicated in these increases. The relative importance of different processes is unresolved as there are few multi-site, multi-land-use evaluations of woody plant encroachment. We measured 70 years of woody cover changes over a 1020 km 2 area covering four land uses (commercial ranching, conservation with elephants, conservation without elephants and communal rangelands) across a rainfall gradient in South African savannahs. Different directions of woody cover change would be expected for each different land use, unless a global factor is causing the increases. Woody cover change was measured between 1940 and 2010 using the aerial photo record. Detection of woody cover from each aerial photograph was automated using eCognitions' Object-based image analysis (OBIA). Woody cover doubled in all land uses across the rainfall gradient, except in conservation areas with elephants in low-rainfall savannahs. Woody cover in 2010 in low-rainfall savannahs frequently exceeded the maximum woody cover threshold predicted for African savannahs. The results indicate that a global factor, of which elevated CO 2 is the likely candidate, may be driving encroachment. Elephants in low-rainfall savannahs prevent encroachment and localized megafaunal extinction is a probable additional cause of encroachment. This article is part of the themed issue ‘Tropical grassy biomes: linking ecology, human use and conservation’.

scholarly journals Estimating asymptomatic, undetected and total cases for the COVID-19 outbreak in Wuhan: a mathematical modeling study

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Xi Huo ◽  
Jing Chen ◽  
Shigui Ruan
Keyword(s):  
Disease Transmission ◽  
Large Scale ◽  
Transmission Rate ◽  
Control Strategies ◽  
Herd Immunity ◽  
Antibody Prevalence ◽  
Screening Process ◽  
Vaccination Programs ◽  
Prevalence Level ◽  
The Impact

Abstract Background The COVID-19 outbreak in Wuhan started in December 2019 and was under control by the end of March 2020 with a total of 50,006 confirmed cases by the implementation of a series of nonpharmaceutical interventions (NPIs) including unprecedented lockdown of the city. This study analyzes the complete outbreak data from Wuhan, assesses the impact of these public health interventions, and estimates the asymptomatic, undetected and total cases for the COVID-19 outbreak in Wuhan. Methods By taking different stages of the outbreak into account, we developed a time-dependent compartmental model to describe the dynamics of disease transmission and case detection and reporting. Model coefficients were parameterized by using the reported cases and following key events and escalated control strategies. Then the model was used to calibrate the complete outbreak data by using the Monte Carlo Markov Chain (MCMC) method. Finally we used the model to estimate asymptomatic and undetected cases and approximate the overall antibody prevalence level. Results We found that the transmission rate between Jan 24 and Feb 1, 2020, was twice as large as that before the lockdown on Jan 23 and 67.6% (95% CI [0.584,0.759]) of detectable infections occurred during this period. Based on the reported estimates that around 20% of infections were asymptomatic and their transmission ability was about 70% of symptomatic ones, we estimated that there were about 14,448 asymptomatic and undetected cases (95% CI [12,364,23,254]), which yields an estimate of a total of 64,454 infected cases (95% CI [62,370,73,260]), and the overall antibody prevalence level in the population of Wuhan was 0.745% (95% CI [0.693%,0.814%]) by March 31, 2020. Conclusions We conclude that the control of the COVID-19 outbreak in Wuhan was achieved via the enforcement of a combination of multiple NPIs: the lockdown on Jan 23, the stay-at-home order on Feb 2, the massive isolation of all symptomatic individuals via newly constructed special shelter hospitals on Feb 6, and the large scale screening process on Feb 18. Our results indicate that the population in Wuhan is far away from establishing herd immunity and provide insights for other affected countries and regions in designing control strategies and planing vaccination programs.

scholarly journals A Full-Newton AC-DC Power Flow Methodology for HVDC Multi-Terminal Systems and Generic DC Network Representation

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1658
Author(s):  
Leandro Almeida Vasconcelos ◽  
João Alberto Passos Filho ◽  
André Luis Marques Marcato ◽  
Giovani Santiago Junqueira
Keyword(s):  
Power Systems ◽  
Direct Current ◽  
Power Flow ◽  
Large Scale ◽  
Flow Problem ◽  
Control Strategies ◽  
Problem Formulation ◽  
Expansion Planning ◽  
Dc Power ◽  
Power Flow Problem

The use of Direct Current (DC) transmission links in power systems is increasing continuously. Thus, it is important to develop new techniques to model the inclusion of these devices in network analysis, in order to allow studies of the operation and expansion planning of large-scale electric power systems. In this context, the main objective of this paper is to present a new methodology for a simultaneous AC-DC power flow for a multi-terminal High Voltage Direct Current (HVDC) system with a generic representation of the DC network. The proposed methodology is based on a full Newton formulation for solving the AC-DC power flow problem. Equations representing the converters and steady-state control strategies are included in a power flow problem formulation, resulting in an expanded Jacobian matrix of the Newton method. Some results are presented based on HVDC test systems to confirm the effectiveness of the proposed approach.

The Control Strategy Study of Doubly-Fed Wind Turbine Participated in Frequency Regulation

2012 ◽  
Vol 512-515 ◽  
pp. 788-793
Author(s):  
Xiao Hua Zhou ◽  
Ming Qiang Wang ◽  
Wei Wei Zou
Keyword(s):  
Wind Turbine ◽  
Control Strategy ◽  
Large Scale ◽  
Control Strategies ◽  
Frequency Control ◽  
Frequency Regulation ◽  
Strategy Study ◽  
Fuzzy Control Strategy ◽  
Doubly Fed ◽  
System Frequency

Traditional decoupling control strategy of doubly-fed induction generator (DFIG) wind turbine makes little contribution to system inertia and do not participate in the system frequency control, the synchronization of large-scale wind power requires wind turbine have the ability to participate in the regulation of power system frequency. This paper adds a frequency control segment to traditional DFIG wind turbine and considers the doubly-fed wind turbine operating on the state of the super-synchronous speed, by analysis the effect of inertia and proportional control strategies, a fuzzy control strategy which combines the advantages of the former two control strategies is proposed, simulation results show that this control strategy can more effectively improve the system frequency response.

scholarly journals Oral Tobaccco and Mortality in India

2016 ◽  
Vol 7 ◽  
pp. IJCM.S25889 ◽  
Author(s):  
Priya Mohan ◽  
Harry A. Lando
Keyword(s):  
Tobacco Control ◽  
Health Care Professionals ◽  
Large Scale ◽  
Control Strategies ◽  
Control Policy ◽  
Control Measures ◽  
Educational Institutions ◽  
Regional Studies ◽  
Gender And Education ◽  
Indian Context

This comprehensive review includes large-scale pan-India surveys and regional studies. Every aspect of smokeless tobacco, including variations in social, economic, demographic, gender, and education stratifiers, is presented. This evidence-based presentation thereby provides insight not only to assess the burden but can serve as a base, leading to the development and encouragement of research in closing the existing gaps in knowledge. It can also provide a track to formulate tobacco control strategies as well as to reinforce and potentially guide tobacco control policy aimed at addressing the tailored needs in the Indian context. The recommendations expand the tobacco control spectrum and are the first of their kind in the literature to focus on cessation programs as a paramedical subject to draw the attention of not only policymakers but also to integrate medical and dental educational institutions, health care professionals, and tobacco users to synergistically develop successful tobacco control measures.

scholarly journals Large-scale Dynamics of Perceptual Decision Information across Human Cortex

2020 ◽  
Author(s):  
Niklas Wilming ◽  
Peter R Murphy ◽  
Florent Meyniel ◽  
Tobias H Donner
Keyword(s):  
Large Scale ◽  
Time Course ◽  
Action Plan ◽  
Frequency Channel ◽  
Human Cortex ◽  
Cortical Hierarchy ◽  
Specific Frequency ◽  
Sensory Evidence ◽  
Visual Cortical ◽  
Endogenous Component

AbstractPerceptual decisions entail the accumulation of sensory evidence for a particular choice towards an action plan. An influential framework holds that sensory cortical areas encode the instantaneous sensory evidence and downstream, action-related regions accumulate this evidence. The large-scale distribution of this computation across the cerebral cortex has remained largely elusive. We developed a regionally-specific magnetoencephalography decoding approach to exhaustively map the dynamics of stimulus- and choice-specific signals across the human cortical surface during a visual decision. Comparison with the evidence accumulation dynamics inferred from behavior enabled us to disentangle stimulus-dependent and endogenous components of choice-predictive activity across the visual cortical hierarchy. The endogenous component was present in primary visual cortex, expressed in a low (< 20 Hz) frequency-band, and its time course tracked, with delay, the build-up of choice-predictive activity in (pre-)motor regions. Our results are consistent with choice-specific cortical feedback signaling in a specific frequency channel during decision formation.

scholarly journals O Ensino da Antibioterapia: Estado da arte

2019 ◽  
Vol 20 ◽  
pp. 632-637
Author(s):  
Maria José Saavedraa ◽  
João Carlos Sousa
Keyword(s):  
Infectious Diseases ◽  
Large Scale ◽  
Action Plan ◽  
Antimicrobial Properties ◽  
Hospital Setting ◽  
Multidrug Resistant ◽  
World Health ◽  
Novel Approach ◽  
Paul Ehrlich ◽  
Alexander Fleming

Resumo A elevada mortalidade pelas doenças infecciosas, sobretudo epidémicas, mobilizou os cientistas na pesquisa de compostos naturais e produtos de síntese química dotados de propriedades antimicrobianas. Fazendo um pouco de história, referimos Paul Ehrlich, que utilizou o primeiro agente quimioterapêutico -Salvarsan, mais tarde Gerhard Domagk, que utilizou um pro-fármaco percursor de uma sulfamida. Em 1928, Alexander Fleming, descobriu de forma “casual” a penicilina, o primeiro antibiótico. Posteriormente em 1941 Howard Florey e Ernest Chain isolam e purificam a penicilina o que permitiu a sua utilização em larga escala -Era dos Antibióticos. A utilização dos antibióticos (AB) no tratamento das doenças infecciosas constituiu um dos maiores avanços da Medicina no séc. XX. No entanto a sua utilização em larga escala promoveu o aumento da incidência de estirpes multiresistentes aos AB, sobretudo em ambiente hospitalar. Adicionalmente verifica-se uma ocorrência cada vez mais elevada de estirpes resistentes na comunidade–humanos, animais e ambiente. O conhecimento dos mecanismos de ação e da ineficácia dos diferentes grupos farmacológicos de antibióticos é vital para o desenvolvimento de futuros microbianos, estando a ser estudados microrganismos do solo com a finalidade de encontrara novos fármacos. De realçar que a OMS preconiza que caminhamos rumo a uma "era pós-antibiótico”. Se não houver um plano de ação global para o "uso racional de antibióticos" a OMS prevê que em 2050 a resistência aos antibióticos, poderá matar mais de 10 milhões de pessoas.Palavras-chave: antibioterapia; resistência; antibióticos Abstract The current research on infectious diseases, especially with epidemic potential, has mobilized the scientific community to research on the natural substance and chemical probing products with antimicrobial properties. In a brief history of antibiotics, we refer to Paul Ehrlich, who used the first chemotherapeutic agent - Salvarsan, later Gerhard Domagk, who used a sulfamide precursor prodrug. In 1928 Alexander Fleming "casually" discovered penicillin, the first antibiotic. Later in 1941 Howard Florey and Ernest Chain isolate and purify penicillin that can be used on a large scale - Antibiotics Era. The use of antibiotics (AB) in the treatment of infectious diseases is one of the greatest advances of medicine in the 19th century. However, its large-scale use has increased the incidence of multidrug-resistant processes in AB, especially in a hospital setting. Besides, there is an increasing occurrence of resistant strains in different communities - humans, animals and in the environment. Understand the mechanisms of action and the ineffectiveness of the diverse pharmacological groups of antibiotics is crucial to provide further new antibiotic therapies in the near future. Recent studies have highlighted the soil-derived microorganisms as a novel approach to identify new drug substances. In this context, it is noteworthy that the World Health Organization (WHO) considers that we are moving towards a “post-antibiotic era”. If there is no global action plan for “rational use of antibiotics” WHO predicts that in 2050 the global impacts of antibiotic resistance on human heath will be catastrophic, killing more than 10 million people worldwide. Keywords: antibiotic therapy; resistence; antibiotics

scholarly journals Robustness Comparison of Synthetic Inertia Strategies for Doubly Fed Induction Generators under Different Operating Conditions

2020 ◽  
Author(s):  
Paulo Andrade Souza ◽  
Renan R. dos Santos ◽  
Manoelito C. N. Filho ◽  
Daniel Barbosa ◽  
Luciano Sales Barros
Keyword(s):  
Wind Energy ◽  
Large Scale ◽  
Control Strategies ◽  
Renewable Energy Sources ◽  
Operating Conditions ◽  
Wind Condition ◽  
Primary Control ◽  
Parameter Uncertainties ◽  
Doubly Fed ◽  
Frequency Behavior

Due to the increasing penetration of Renewable Energy Sources (RES) such as wind energy in electrical grids, Wind Energy Conversion Systems (WECS) participation in primary control is becoming required including the Doubly Fed Induction Generator (DFIG)-based WECS. High integration of large scale DFIG-based WECS brings new challenges to their primary control support, and more strongly due to the wind condition and grid parameter uncertainties. One of the most used types of control strategy for DFIG-based WECS primary support is the synthetic inertia, however, robustness of these techniques have not been tested. In this work three synthetic inertia control strategies will be tested under different operating conditions of wind speed, frequency and voltage sag. For testing the DFIG-based WECS, it was modeled on ATP including its control systems and the results quantified the controllers robustness on the tested controllers with respect to transient frequency behavior.

scholarly journals Monitoring of Urban Black-Odor Water Based on Nemerow Index and Gradient Boosting Decision Tree Regression Using UAV-Borne Hyperspectral Imagery

2019 ◽  
Vol 11 (20) ◽  
pp. 2402 ◽  
Author(s):  
Wei ◽  
Huang ◽  
Wang ◽  
Wang ◽  
Zhou ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Decision Tree ◽  
Regression Models ◽  
Large Scale ◽  
Hyperspectral Imagery ◽  
Action Plan ◽  
Training Dataset ◽  
Gradient Boosting ◽  
Pollution Level ◽  
Urban Habitat

The formation of black-odor water in urban rivers has a long history. It not only seriously affects the image of the city, but also easily breeds germs and damages the urban habitat. The prevention and treatment of urban black-odor water have long been important topics nationwide. “Action Plan for Prevention and Control of Water Pollution” issued by the State Council shows Chinese government’s high attention to this issue. However, treatment and monitoring are inextricably linked. There are few studies on the large-scale monitoring of black-odor water, especially the cases of using unmanned aerial vehicle (UAV) to efficiently and accurately monitor the spatial distribution of urban river pollution. Therefore, in order to get rid of the limitations of traditional ground sampling to evaluate the point source pollution of rivers, the UAV-borne hyperspectral imagery was applied in this paper. It is hoped to grasp the pollution status of the entire river as soon as possible from the surface. However, the retrieval of multiple water quality parameters will lead to cumulative errors, so the Nemerow comprehensive pollution index (NCPI) is introduced to characterize the pollution level of urban water. In the paper, the retrieval results of six regression models including gradient boosting decision tree regression (GBDTR) were compared, trying to find a regression model for the retrieval NCPI in the current scenario. In the first study area, the retrieval accuracy of the training dataset (adjusted_R2 = 0.978), and test dataset (adjusted_R2 = 0.974) was higher than that of the other regression models. Although the retrieval effect of random forest is similar to that of GBDTR in both training accuracy and image inversion, it is more computationally expensive. Finally, the spatial distribution graphs of NCPI and its technical feasibility in monitoring pollution sources were investigated, in combination with field observations.

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