Hasil untuk "General. Including nature conservation, geographical distribution"

J. Sunday, G. Pecl, S. Frusher et al.

Andrew C. Poje, Takaya Uchida, Takaya Uchida et al.

We address the question of separating the ocean’s deterministic response to time-dependent forcing from its intrinsic chaotic variability. Ideally, one could compute the ensemble mean directly without performing numerous realizations, but this requires knowledge or closure of the second-order statistics — the classical turbulent-closure problem, here recast for a non-equilibrium, geophysical setting. Building on the ideas of nonlinear midlatitude ocean adjustment, we examine this problem using idealized quasi-geostrophic (QG) double-gyre ensembles subjected to episodic temporal variations in wind forcing. Our objective here is not to develop a subgrid parameterization of unresolved eddies, but rather to construct and test prognostic equations for the ensemble mean itself, using the simplest possible closure assumptions. We find that the performance of ensemble mean closures is highly dependent on the spatiotemporal structure of the forcing. Under slowly varying forcing, approximate closures reproduce the mean evolution reasonably well; under rapidly varying, near-zero-mean forcing, the simplest ensemble-mean closures fail, even at the level of basin-averaged total energy and enstrophy. In both regimes, the ensemble-mean response is not simply the accumulated imprint of the applied forcing, but instead appears as a continuing, non-equilibrated dialogue between the mean and eddy fields.

Laxmi Rai, Kritan Rai, Bijoy Chhetri

This article highlights a novel photographic record of the endemic species, Red-naped Ibis of the Indian sub-continent from Sikkim Himalaya. We documented the bird during a field visit on 27 July 2024, in Jorethang, South Sikkim. This finding expands our understanding of the distribution and diversity of avifauna in the state, highlighting the need for further exploration, research, and conservation in Sikkim Himalaya.

Jiangtao Bai, Yutong Yan, Xinyun Bai

In recent years, the International Maritime Organization (IMO) has set strict emission standards for the shipping industry, which has raised high demands for ship emission reduction technologies. This review analyzes the research status of ship emission reduction technologies using bibliometric methods based on 714 publications from the Social Science Citation Index (SSCI) and SCI-Expanded (SCIE) databases from 2000 to 2024, and use VOSviewer software for the visualization of publications. It identifies key trends, productive entities and key contributors, and research hotspots in the field. The core findings are that green power technologies, digital intelligence technologies, and emission reduction technologies are current focal points. Future research should focus on finding optimal solutions for alternative marine fuels, clarifying the low-carbon transformation pathways for ships, and promoting effective follow-up actions from all relevant parties.

Tim Benedikt von See, Jens Greinert, Jens Greinert et al.

Sediment plumes created by dredging or mining activities have an impact on the ecosystem in a much larger area than the mining or dredging area itself. It is therefore important and sometimes mandatory to monitor the developing plume to quantify the impact on the ecosystem including its spatial-temporal evolution. To this end, a Bayesian Optimization (BO)-based approach is proposed for plume monitoring using autonomous underwater vehicles (AUVs), which are used as a sensor network. Their paths are updated based on the BO, and additionally, a split-path method and the traveling salesman problem are utilized to account for the distances the AUVs have to travel and to increase the efficiency. To address the time variance of the plume, a sliding-window approach is used in the BO and the dynamics of the plume are modeled by a drift and decay rate of the suspended particulate matter (SPM) concentration measurements. Simulation results with SPM data from a simulation of a dredge experiment in the Pacific Ocean show that the method is able to monitor the plume over space and time with good overall estimation error.

Nicolas Gonthier

Rapid evolution of territories due to climate change and human impact requires prompt and effective updates to geospatial databases maintained by the National Mapping Agency. This paper presents a comprehensive overview of change detection methods tailored for the operational updating of large-scale geographic databases. This review first outlines the fundamental definition of change, emphasizing its multifaceted nature, from temporal to semantic characterization. It categorizes automatic change detection methods into four main families: rule-based, statistical, machine learning, and simulation methods. The strengths, limitations, and applicability of every family are discussed in the context of various input data. Then, key applications for National Mapping Agencies are identified, particularly the optimization of geospatial database updating, change-based phenomena, and dynamics monitoring. Finally, the paper highlights the current challenges for leveraging change detection such as the variability of change definition, the missing of relevant large-scale datasets, the diversity of input data, the unstudied no-change detection, the human in the loop integration and the operational constraints. The discussion underscores the necessity for ongoing innovation in change detection techniques to address the future needs of geographic information systems for national mapping agencies.

Adama Taonda, Issouf Zerbo, Sié Sylvestre Da et al.

J. Blanchard, R. Watson, E. Fulton et al.

A. Heinimann, O. Mertz, S. Frolking et al.

Mosaic landscapes under shifting cultivation, with their dynamic mix of managed and natural land covers, often fall through the cracks in remote sensing–based land cover and land use classifications, as these are unable to adequately capture such landscapes’ dynamic nature and complex spectral and spatial signatures. But information about such landscapes is urgently needed to improve the outcomes of global earth system modelling and large-scale carbon and greenhouse gas accounting. This study combines existing global Landsat-based deforestation data covering the years 2000 to 2014 with very high-resolution satellite imagery to visually detect the specific spatio-temporal pattern of shifting cultivation at a one-degree cell resolution worldwide. The accuracy levels of our classification were high with an overall accuracy above 87%. We estimate the current global extent of shifting cultivation and compare it to other current global mapping endeavors as well as results of literature searches. Based on an expert survey, we make a first attempt at estimating past trends as well as possible future trends in the global distribution of shifting cultivation until the end of the 21st century. With 62% of the investigated one-degree cells in the humid and sub-humid tropics currently showing signs of shifting cultivation—the majority in the Americas (41%) and Africa (37%)—this form of cultivation remains widespread, and it would be wrong to speak of its general global demise in the last decades. We estimate that shifting cultivation landscapes currently cover roughly 280 million hectares worldwide, including both cultivated fields and fallows. While only an approximation, this estimate is clearly smaller than the areas mentioned in the literature which range up to 1,000 million hectares. Based on our expert survey and historical trends we estimate a possible strong decrease in shifting cultivation over the next decades, raising issues of livelihood security and resilience among people currently depending on shifting cultivation.

Radhika Sood, Shalini Dhyani

Farahnaz Khajehnasiri, Ali Mohammad Mosadeghrad, Mohammad Hossein Alibeiginejad

Background The equitable distribution of workforce is imperative for achieving public health goals. This study was conducted to evaluate the equity of the distribution of general practitioners (GPs) in Iran. Methods In this descriptive and cross-sectional study, data from the Information System of Benefits for Iranians and the Iranian Statistics Center were utilized. The study population encompasses all GPs operating in Iran in 2022. To assess equity in the geographical distribution of physicians, the Gini coefficient and Lorenz curve were calculated using Excel software. Additionally, ArcGIS software was used to create a distribution map. Results The population of Iran and active GPs in 2022 were 85,874,000 and 67,852 respectively, resulting in an average of 7.9 active GPs per 10,000 people. The provinces of Yazd, Tehran, Mazandaran, and Fars exhibited the highest concentration of active GPs per capita, collectively representing more than 28% of the population and 37% of the active GPs. Fifty percent of the active GPs were women. The Gini coefficients for the provincial and intercity distributions of GPs were 0.08 and 0.2, respectively. Conclusion The distribution of GPs among provinces and cities was deemed fair and relatively fair, respectively. Iran has a lower ratio of GPs per capita than the European nations. Policymakers should pay more attention to the implementation of appropriate policies with the aim of increasing equity in the geographical distribution of GPs in the country.

J. Lawler, S. Shafer, D. White et al.

Stephanie M. Koontz, Federico López‐Borghesi, Stacy A. Smith et al.

Abstract Species translocations are increasingly common in rare plant conservation. Wild populations can provide basic ecological knowledge to improve their chance of success. In the heavily fragmented Florida scrub, USA, many listed species require translocations to persist, including Dicerandra christmanii. In 1994, we began monitoring the only protected population of D. christmanii growing both in gaps (open areas) within the shrub matrix and on roadsides. In 2010, we augmented this population by adding plants and seeds to unoccupied gaps. In 2012, we introduced plants to a separate protected site to create a new population. We evaluated early translocation success using generalized linear mixed‐effect models of vital rate variation among habitat types. Survival probability increased with size, peaking at 0.6–0.8, and was lowest in augmentations and highest in introductions. Growth increased with plant size across all habitat types, except for the largest adults which experienced senescence. Naturally recruited plants in gaps showed the highest reproduction probability and fecundity at smaller sizes, but larger plants in translocations had the highest fecundity. Yearling recruitment was higher in translocated plants relative to naturally recruited plants in gaps during the initial years following outplanting. Experimental components of translocations also affected outplanting performance with positive effects of fire. These analyses suggest a high potential for translocations to become established and contribute to species recovery.

Samantha King, Antoine Saint-Amand, Brian K. Walker et al.

Since the 1980s, populations of Acropora cervicornis and A. palmata have experienced severe declines due to disease and anthropogenic stressors; resulting in their listing as threatened, and their need for restoration. In this study, larval survival and competency data were collected and used to calibrate a very high-resolution hydrodynamic model (up to 100m) to determine the dispersal patterns of Acropora species along the Florida’s Coral Reef. The resulting connectivity matrices was incorporated into a metapopulation model to compare strategies for restoring Acropora populations. This study found that Florida’s Coral Reef was historically a well-connected system, and that spatially selective restoration may be able to stimulate natural recovery. Acropora larvae are predominantly transported northward along the Florida’s Coral Reef, however southward transport also occurs, driven by tides and baroclinic eddies. Local retention and self-recruitment processes were strong for a broadcast spawner with a long pelagic larval duration. Model simulations demonstrate that it is beneficial to spread restoration effort across more reefs, rather than focusing on a few reefs. Differences in population patchiness between the Acropora cervicornis and A. palmata drive the need for different approaches to their management plans. This model can be used as a tool to address the species-specific management to restore genotypically diverse Acropora populations on the Florida’s Coral Reef, and its methods could be expanded to other vulnerable populations.

Fabio Rindi, Fabio Rindi, Alba Vergés et al.

Active marine restoration is strongly encouraged to prevent the loss of the valuable habitats formed by Cystoseira sensu lato species, since they enhance biodiversity and preserve ecosystem functions and services. Current restoration interventions are mainly based on recruitment enhancement methods by deploying bags with fertile receptacles in situ or by outplanting juveniles grown ex situ under laboratory conditions. These methods allow the recovery of endangered species avoiding the depletion of the donor populations. In all cases, a priori knowledge of the reproductive phenology and recruitment periods of the species to be restored is essential, since the success of restoration techniques relies on collecting fertile branches and the obtention and survival of recruits. For their collection, identified donor populations characterized by dense Cystoseira s.l. cover should be studied. Specifically, monitoring the reproductive phenology of populations is crucial to detect the period of the year in which they develop mature reproductive structures and to understand how it might be linked to environmental conditions. Then, these general patterns on the reproductive phenology of Cystoseira s.l. species are essential to determine the most suitable time and conditions to plan for the most effective restoration action. Here, we provide a cost-effective and friendly protocol that can be easily and widely implemented for all Cystoseira s.l. species. We pose that this protocol provides a standardized and useful methodology to understand the environmental factors driving the optimal periods for sampling fertile branches across the Mediterranean Sea, and thus it can be an essential tool to plan future restoration actions.

David Fellner, Thomas I. Strasser, Wolfgang Kastner et al.

The changes in the electric energy system toward a sustainable future are inevitable and already on the way today. This often entails a change of paradigm for the electric energy grid, for example, the switch from central to decentralized power generation which also has to provide grid-supporting functionalities. However, due to the scarcity of distributed sensors, new solutions for grid operators for monitoring these functionalities are needed. The framework presented in this work allows to apply and assess data-driven detection methods in order to implement such monitoring capabilities. Furthermore, an approach to a multi-stage detection of misconfigurations is introduced. Details on implementations of the single stages as well as their requirements are also presented. Furthermore, testing and validation results are discussed. Due to its feature of being seamlessly integrable into system operators' current metering infrastructure, clear benefits of the proposed solution are pointed out.

Paul Disberg, Gijs Nelemans

The more gravitational wave sources are detected, the better the mass distribution of binary black holes (BBHs) becomes known. This stellar graveyard shows several features, including an apparent mass gap which makes the distribution bimodal. The observed chirp mass distribution, in turn, appears to be trimodal. We aim to investigate to which extend we can explain the observed mass distribution with stellar evolution, specifically with the hypothesis that the mass gap is caused by the difference between successful and failed supernovae (SNe). We pose a hypothetical remnant function, based on literature of stellar evolution simulations, which relates initial mass to remnant mass, includes a black hole island and produces a bimodal remnant distribution. Moreover, we look at observed type II SN rates in an attempt to detect the effect of failed SNe. Finally, using a simplified estimation of binary evolution, we determine the remnant distribution resulting from our remnant function and compare it to observation. We find that failed SNe lower type II SN rates by approximately 25%, but the inferred rate from SN surveys is not accurate enough to confirm this. Furthermore, our estimation based on the remnant function produces a mass distribution that matches the general shape of the observed distributions of individual as well as chirp masses. Based on our research, we conclude that the failed SNe mechanism and the presence of the black hole island are a natural hypothesis for explaining the individual BBH mass distribution and chirp mass distribution. However, for a more firm conclusion more detailed simulations are needed.

Lulu Qu, Yurui Li, Yongsheng Wang et al.