Climate variability and individual motivations for participating in political violence

Climate shocks are argued to affect the likelihood of conflict through individual economic outcomes that change the individual opportunity costs of participation in violent activities. Studies testing this proposition, however, either fail to answer convincingly because they use aggregated data, because they rely on observed controls and strong assumptions about variable independence, or because their study sample is restricted to particular conflicts. This article uses two rounds in Afrobarometer where respondents were asked about participation in politically motivated violence as well as how their living conditions had changed in the last year. To get around endogeneity problems, perceived changes in living conditions are instrumented using a standardized precipitation-evapotranspiration index (SPEI). The study finds that participation in violence would, on average, have been more likely if an individual experienced a deterioration of living conditions than if it had not, in the subpopulation in Africa whose living conditions are affected by droughts.     

The elephant in the room: The hidden costs of leasing individual transferable fishing quotas

Despite the increasingly positive reviews of individual transferable quotas (ITQs), few studies have considered how quota leasing activities can reduce the economic benefits to society and to fishermen operating under the ITQ fisheries system. This analysis reveals negative economic impacts of ITQs previously overlooked by examining the extent of quota leasing and the relationship between the catch value, the cost of fishing, and the quota lease price in the BC halibut fishery, long considered a poster child for ITQs. Findings challenge assumptions of economic theory used to promote the benefits of ITQs.     

New Zealand seafood firm competitiveness in export markets: The role of the quota management system and aquaculture legislation

New Zealand's quota management system (QMS) was implemented in 1986 to address problems caused by a regulated open entry management system in place for the previous two decades. Excess capacity in the inshore fisheries caused several stocks to become depleted and conflicts to intensify between fishing sectors. The allocation of individual transferable quota (ITQ) was viewed as the best way to improve efficiency within the over-capitalised inshore fisheries and provide incentives for developing the deepwater fisheries. The expected benefits of the QMS fit with the political climate at that time, as the government was using market forces to address the deteriorating economy. This article outlines the results of a research project that involved four medium to large-sized, highly vertically integrated New Zealand seafood firms. The purpose of the project was to identify these firms’ sources of competitiveness in export markets and the process the firms used to develop sources of competitiveness, while adapting to rapid and radical changes to the political and business environment and transformation of the fisheries management system. The project's results show that the basis to seafood firm competitiveness is the security of supply to the fisheries resource provided by the QMS and aquaculture legislation. The project also outlines the role that government policies have in sustaining firm- and industry-level competitiveness. This article contributes to the broader discussion on the application of ITQ and other types of long-term access rights to the management of fisheries and does not express the views of the Ministry of Fisheries.     

ITQs under illegal fishing: An application to the red shrimp fishery in Chile

We study an individual transferable quota system with imperfect enforcement. We apply a model of individual fisherman behavior to the red shrimp (Pleuroncodes monodon) fishery in central-southern Chile. Simulation results suggest that illegal fishing could generate a 21% increase in fishing effort, resulting in a 13% increase in catch and a 2% lower quota price in comparison with the results of a system that operates under perfect compliance. The results are sensitive to changes in the level of fish abundance, total allowable catch, and the design of enforcement to induce compliance.     

Self-governance within a QMS framework—The evolution of self-governance in the New Zealand Bluff oyster fishery

This paper examines efforts to develop stakeholder led self-governance in the Bluff oyster fishery. The paper focuses on collaborative management and its ability to address some of the unintended consequences of management. The Bluff oyster fishery's administrative, biological, and economic performances are analysed to assess whether or not the participatory management model, in this case fisheries self-governance, complements individual transferable quota (ITQ) for this inshore shellfish fishery.The paper argues that the Bluff oyster fishery's current self-governance model, based on a fishery plan, aids in improving the performance of the fishery, and that the Bluff oyster fishery has the capacity to shift further towards a stakeholder led self-regulated fishery.     

Tree species classification using UAS-based digital aerial photogrammetry point clouds and multispectral imageries in subtropical natural forests

Tree species composition of forest stand is an important indicator of forest inventory attributes for assessing ecosystem health, understanding successional processes, and digitally displaying forest biodiversity. In this study, we acquired high spatial resolution multispectral and RGB imagery over a subtropical natural forest in southwest China using a fixed-wing UAV system. Digital aerial photogrammetric (DAP) technique was used to generate multi-spectral and RGB derived point clouds, upon which individual tree crown (ITC) delineation algorithms and a machine learning classifier were used to identify dominant tree species. To do so, the structure-from-motion method was used to generate RGB imagery-based DAP point clouds. Then, three ITC delineation algorithms (i.e., point cloud segmentation (PCS), image-based multiresolution segmentation (IMRS), and advanced multiresolution segmentation (AMRS)) were used and assessed for ITC detection. Finally, tree-level metrics (i.e., multispectral, texture and point cloud metrics) were used as metrics in the random forest classifier used to classify eight dominant tree species. Results indicated that the accuracy of the AMRS ITC segmentation was highest (F₁-score = 82.5 %), followed by the segmentation using PCS (F₁-score = 79.6 %), the IMRS exhibited the lowest accuracy (F₁-score = 78.6 %); forest types classification (coniferous and deciduous) had a higher accuracy than the classification of all eight tree species, and the combination of spectral, texture and structural metrics had the highest classification accuracy (overall accuracy = 80.20 %). In the classification of both eight tree species and two forest types, the classification accuracies were lowest when only using spectral metrics, indicated that the texture metrics and point cloud structural metrics had a positive impact on the classification (the overall accuracy and kappa accuracy increased by 1.49–4.46 % and 2.86–6.84 %, respectively).     

Red snapper discards in the Gulf of Mexico: Fishermen's perceptions following the implementation of Individual Fishing Quotas

In 2007, an Individual Fishing Quota (IFQ) program was introduced to the valuable red snapper (Lutjanus campechanus) fishery in the US Gulf of Mexico. This study assessed the current perceived scale and causes of red snapper discarding in the Gulf in recent years within the commercial reef fish fishery, according to commercial fishermen. Data were collected through interviews, which took place with fishermen in April and May 2010, and which were unexpectedly halted due to the Deepwater Horizon oil spill that occurred in late April 2010. Results suggest that for those fishermen fully participating in the IFQ program, snapper discarding has decreased since program implementation. For those not fully involved in the program (e.g., due to participation costs), discarding has likely since increased.     

金云母—蛭石间层矿物分晶层晶体化学式的计算及意义

金云母－蛭石间层矿物由金云母晶层与蛭石晶层交叠排列而成，采用一般计算方法得出的晶体化学式不能充分揭示结构中金云母晶层与蛭石晶层各自的晶体化学特征。本文以化学成分分析与阳离子容量为基础，假定可交换性阳离子均为蛭石晶层层间阳离子，非交换性阳离子为金云母晶层层间阳离子，金云母晶层与蛭石晶层具有相同的八面体层等，计算出了结构中两种晶层的分晶层晶体化学式，确定了结构中两种晶层的比例和蛭石晶层的电荷数。并在此基础上讨论了新疆尉犁蛭石矿金云母－蛭石间层矿物的晶体化学特征。结果表明该方法设计合理，符合晶体化学原理，所计算的数据可靠。利用该方法计算出的两种晶层的比例为金云母－蛭石1：1规则间层矿物的确定提供了必要的依据。也为其它类似间层矿物的研究提供了一种计算分晶层晶体化学式的可行方法。     

DBSCAN Clustering Algorithm for the Detection of Nearby Open Clusters Based on Gaia-DR2two

In this paper, we attempt to use the DBSCAN (Density-Based Spatial Clustering of Applications with Noise) clustering algorithm to detect nearby open clusters based on the Gaia Data Release 2 (Gaia-DR2). We select 594284 stars (within a distance of 100 pc to the Sun) from the Gaia-DR2 catalog, and construct a five-dimensional phase space (three-dimensional spatial position and two-dimensional proper motion) in order to obtain reliable cluster members. At the data preprocessing stage, we normalize each dimension of data to the [0, 1] interval in order to avoid the effect of inconsistent units. Then, we use the k-dist graphs to determine the input parameters of the DBSCAN Algorithm. Finally, we obtain 133 reliable members using the DBSCAN algorithm, which correspond to two open clusters—Hyades and Coma. According to these cluster members, the distances to the Hyades and Coma clusters are determined to be (6.5 ± 0.3) pc and (4.9 ± 0.4) pc, respectively.