USDA Forest Service - Research Papers PNW-RP最新文献

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Composition of the wolf’s Canis lupus L. diet in the Wigry National Park 威格里国家公园里狼的饮食组成
USDA Forest Service - Research Papers PNW-RP Pub Date : 2018-06-01 DOI: 10.2478/frp-2018-0013
R. Mysłajek, S. Nowak, M. Romański, Katarzyna Tołkacz
{"title":"Composition of the wolf’s Canis lupus L. diet in the Wigry National Park","authors":"R. Mysłajek, S. Nowak, M. Romański, Katarzyna Tołkacz","doi":"10.2478/frp-2018-0013","DOIUrl":"https://doi.org/10.2478/frp-2018-0013","url":null,"abstract":"Abstract The diet of wolves Canis lupus L. was assessed in the Wigry National Park in North-Eastern Poland, which overlaps with the Natura 2000 site “Ostoja Wigierska”. The content of a total of 149 scat samples was collected in 2017 and analysed in order to determine dietary composition. Wolves primarily feed on wild ungulates, which make up 75.4% of food biomass. Despite the fact that wild boar Sus scrofa L. and red deer Cervus elaphus L. dominate in the ungulate community in the study area, the primary prey species was observed to be roe deer Capreolus capreolus L. with 39.6%, while red deer and wild boar only constituted 18.7% and 8.3% of the food biomass, respectively. Additionally, beaver Castor fiber L. was found to be an important prey (10.9%) as well and livestock accounted for 15.1% of all biomass consumed. The livestock eaten by wolves also included carcasses of domestic animals illegally disposed of in the forest. We therefore conclude that decisions on the management of the wolf’s food base within protected areas, such as national parks or Natura 2000 sites, should be preceded by intensive local studies.","PeriodicalId":35347,"journal":{"name":"USDA Forest Service - Research Papers PNW-RP","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75395530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 4
Educational aspects of the profession of ‘forest machinery operator’ in view of survey results 根据调查结果,“森林机械操作员”职业的教育方面
USDA Forest Service - Research Papers PNW-RP Pub Date : 2018-06-01 DOI: 10.2478/frp-2018-0020
A. Rutkowska, K. Adamowicz
{"title":"Educational aspects of the profession of ‘forest machinery operator’ in view of survey results","authors":"A. Rutkowska, K. Adamowicz","doi":"10.2478/frp-2018-0020","DOIUrl":"https://doi.org/10.2478/frp-2018-0020","url":null,"abstract":"Abstract In the early 1990s, an employment reduction in the State Forests caused the lowest-income employees to be transferred to external service providers. At the same time, due to the lack of students applying in this field, numerous vocational schools were shut down. At present, professions in the forestry sector are characterized by work under harsh conditions combined with low pay and are thus rarely chosen by young people. As a result, this service sector’s average age is increasing very visibly. The aim of this paper was to gather information about the motivation of the students who did decide to begin training in this field and their professional aspirations. Our work is based on data obtained from forestry schools and a 9-question survey. Questions in the survey concerned the motivation to become an operator of forest machines, family traditions related to this profession, professional interests and plans for the future. The data analysis revealed that forestry education at the level of vocational schools is practically inexistent. For the past six years, the only unit that trained new forestry workers continuously was the Forestry School in Rogoziniec. The school’s graduates primarily pick up the profession of harvester operator and forwarder operator. Even more alarming is the fact that most of this school’s students are aware of the present employment conditions in Poland and are considering going abroad to find jobs. Therefore, in order to retain the newly trained workforce, it is necessary to improve the attractiveness of the forestry professions and to introduce systemic solutions for the development of qualifications and competences, which should be of interest to both forestry entrepreneurs and the State Forests.","PeriodicalId":35347,"journal":{"name":"USDA Forest Service - Research Papers PNW-RP","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76992560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Influence of climatic conditions and air pollution on radial growth of Scots pine (Pinus sylvestris L.) in Szczecin’s city forests 气候条件和空气污染对Szczecin城市林中苏格兰松径向生长的影响
USDA Forest Service - Research Papers PNW-RP Pub Date : 2018-06-01 DOI: 10.2478/frp-2018-0011
A. Cedro, Bernard Cedro
{"title":"Influence of climatic conditions and air pollution on radial growth of Scots pine (Pinus sylvestris L.) in Szczecin’s city forests","authors":"A. Cedro, Bernard Cedro","doi":"10.2478/frp-2018-0011","DOIUrl":"https://doi.org/10.2478/frp-2018-0011","url":null,"abstract":"Abstract The aim of the present work was to characterize the growth – climate relationship of pines growing in the Szczecin city forests in intensively used recreational areas and to identify the effect of air pollutants emitted by a nearby chemical factory on tree-ring width. Our research area was located in the Głębokie forest complex, which is one of the most frequently visited. The chemical factory Police that produces fertilizers is located at a distance 11 km away from the study plot. The largest emissions of pollutants from the factory in terms of volume occurred in the 1980s and early 1990s. Wood samples were collected from Scots pine (Pinus sylvestris L.) with the Pressler borer from 30 trees and examined using standard dendrochronological methodology. The result was a local chronology of 169 years from 1848–2016. Dendroclimatological analyses indicated that the weather conditions at the turn from winter to spring are the dominant factors influencing radial growth. For example, higher than average temperatures in February, March and April result in a wide tree-ring in the upcoming growth season. Following Nowacki and Abram’s method, we also determined the relative growth change in order to delimit the timeframe when air pollution potentially alters tree-ring width. Due to the lack of data for the period 1848–1945, the increasing and decreasing relative growth could not be linked to specific events. For the period 1944–1972 however, we observed and increase in the tree-ring width, which in this case can be attributed to favorable weather conditions. The final period, 1973–1991, on the other hand showed the strongest decline in annual growth throughout our chronology and this was largely due to the nearby chemical factories, which released huge amounts of pollution into the atmosphere during this period. At present, despite new technologies and a decrease in overall production by the nearby chemical factory, we found a negative trend in ring width dynamics indicating a need for pollutant monitoring and further research.","PeriodicalId":35347,"journal":{"name":"USDA Forest Service - Research Papers PNW-RP","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87001703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 5
Plant communities of the Czerwona Woda River Valley (Stołowe Mountains National Park) zerwona Woda河谷的植物群落(Stołowe山地国家公园)
USDA Forest Service - Research Papers PNW-RP Pub Date : 2018-06-01 DOI: 10.2478/frp-2018-0019
R. Pielech, M. Malicki, M. Smoczyk, A. Jagodziński, M. Dyderski, P. Horodecki, Sylwia Wierzcholska, M. Skorupski, Jacek Kamczyc, I. Kałucka, Mariusz Hachułka, A. Gazda
{"title":"Plant communities of the Czerwona Woda River Valley (Stołowe Mountains National Park)","authors":"R. Pielech, M. Malicki, M. Smoczyk, A. Jagodziński, M. Dyderski, P. Horodecki, Sylwia Wierzcholska, M. Skorupski, Jacek Kamczyc, I. Kałucka, Mariusz Hachułka, A. Gazda","doi":"10.2478/frp-2018-0019","DOIUrl":"https://doi.org/10.2478/frp-2018-0019","url":null,"abstract":"Abstract The Czerwona Woda River is the main watercourse in the Stołowe Mountains National Park and drains the major part of the Stołowe Mts. It was regulated in the past, but its channel has been spontaneously naturalised. Now, managed spruce forests grow along almost the entire length of this small mountain stream. The aims of the present study were to investigate diversity of plant communities connected with the Czerwona Woda stream and to prepare detailed vegetation maps. The results obtained can potentially be a reference for future restoration projects implemented in the Stołowe Mountains National Park. As a result of vegetation mapping, there were distinguished 20 plant communities representative of the current vegetation and 3 communities representative of the potential vegetation. Phytosociological data on the vegetation was documented by making 62 phytosociological relevés. Based on these, 9 forest communities were distinguished, of which 3 were classified into associations, 1 – into alliance, 5 – into secondary forest communities. Furthermore, there were distinguished 14 non-forest communities, of which 10 were classified into associations. Several of the phytosociological classes distinguished have been reported for the first time in the Stołowe Mountains National Park.","PeriodicalId":35347,"journal":{"name":"USDA Forest Service - Research Papers PNW-RP","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90272268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 4
Forest policy goals in Poland in light of the current forestry aims in Europe Part 2. Forest policy priorities in Europe 根据欧洲目前的林业目标,波兰的森林政策目标第二部分。欧洲森林政策的优先事项
USDA Forest Service - Research Papers PNW-RP Pub Date : 2018-06-01 DOI: 10.2478/frp-2018-0018
A. Kaliszewski
{"title":"Forest policy goals in Poland in light of the current forestry aims in Europe Part 2. Forest policy priorities in Europe","authors":"A. Kaliszewski","doi":"10.2478/frp-2018-0018","DOIUrl":"https://doi.org/10.2478/frp-2018-0018","url":null,"abstract":"Abstract The aim of the paper was to evaluate the priorities set for policy-making in forestry formulated under the Forest Europe process and in programmes, policies, strategies and legal acts of the European Union after 1997, which is also the year when the Polish ‘National Forest Policy’ was adopted by the Council of Ministers. During the last two decades, rapid policy development has been occurring Europe-wide. Forest policy goals defined within the Forest Europe process have also been reflected in EU’s strategic documents and legal acts and both processes are complementary as well as influencing each other. Forest policy priorities after 1997 cover all three major aspects of sustainable forest management (SFM): ecological, economic and social. However, the main emphasis has been put on economic and social aspects of SFM. The key priorities defined in numerous Forest Europe and EU documents are the following: enhancing the role of forests and forest management in mitigating climate change including the promotion of production and wide use of wood; adapting forests to climate change and changing environmental conditions; conserving, protecting and enhancing forest biodiversity; enhancing the role of forests and forest management in rural development; fostering coordination and cross-sectoral cooperation within forestry. The need for enhancing forest research has been pointed out in almost all analysed Forest Europe commitments as well as in numerous EU documents.","PeriodicalId":35347,"journal":{"name":"USDA Forest Service - Research Papers PNW-RP","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90688970","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Slenderness of trees in black locust stands 黑槐树林中的细长树木
USDA Forest Service - Research Papers PNW-RP Pub Date : 2018-06-01 DOI: 10.2478/frp-2018-0012
S. Bijak, Katarzyna Orzoł
{"title":"Slenderness of trees in black locust stands","authors":"S. Bijak, Katarzyna Orzoł","doi":"10.2478/frp-2018-0012","DOIUrl":"https://doi.org/10.2478/frp-2018-0012","url":null,"abstract":"Abstract This paper investigates the slenderness of black locust (Robinia pseudoacacia) trees in relation to the biosocial status of the trees, stand age class, crown parameters and habitat type. The research material was collected on 35 research plots in the Sława Śląska, Sulechów and Głogów forest districts in western Poland and comprises 1058 trees. For each tree, we measured height (h) as well as diameter at breast height (d) and determined its biosocial status (Kraft class), crown length (CL) and relative crown length (rCL). The age class and habitat type were assessed at the plot level. Because the obtained values for slenderness (s=h/d) diverged significantly from the normal distribution, we used Kruskal-Wallis and Mann-Whitney tests to investigate the influence of the above-mentioned parameters on the h/d ratio. Black locust slenderness ranged from 0.31 to 1.95 with an average of 0.91 (standard deviation 0.24). It furthermore differed significantly between Kraft classes (the higher the biosocial status, the lower the slenderness) and age classes (the older the trees, the lower their slenderness). We also found a significant effect of the habitat type (in oligotrophic sites trees formed more slender trunks than in mesotrophic sites) and crown parameters on the h/d ratio (decreasing with increasing crown length and relative crown length). The obtained results suggest that the slenderness of black locust does not differ substantially from native broadleaved trees in Poland.","PeriodicalId":35347,"journal":{"name":"USDA Forest Service - Research Papers PNW-RP","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83295151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
Evaluation of the corridor method for oak (Quercus sp.) cultivation using research objects in the Mircze and Kościan Forest Districts as an example 以Mircze林区和Kościan林区为研究对象,评价廊道法在栎树种植中的应用
USDA Forest Service - Research Papers PNW-RP Pub Date : 2018-03-01 DOI: 10.2478/frp-2018-0004
R. Paluch, W. Gil
{"title":"Evaluation of the corridor method for oak (Quercus sp.) cultivation using research objects in the Mircze and Kościan Forest Districts as an example","authors":"R. Paluch, W. Gil","doi":"10.2478/frp-2018-0004","DOIUrl":"https://doi.org/10.2478/frp-2018-0004","url":null,"abstract":"Abstract The corridor method of oak (Quercus sp) cultivation is an old, forgotten silvicultural method. It was developed around the turn of the 19th and 20th century on the south-eastern borders of Poland (Podole, Wołyń) and Russia and made use of other species such as hornbeam, linden and birch as a cover for oak, which is a tree species sensitive to frosts. The nowadays recurring phenomenon of oak disease initiated a search for silvicultural alternatives and thus the usefulness of reviving the corridor method for oak regeneration was investigated by examining existing tree stands established in this way. Our research plots were located in five young stands and two in mature as well as old stands. In the stands of the 2nd and 3rd age classes, the density of oaks was observed to be 1500–3500/ha, which accounted for 30–50%. The density of oak in old stands (7th age class) was similar to model-predicted values. Furthermore, the corridor method gave very good production results as exemplified by the oak stands growing on the fresh broadleaved site, which had a very high stand quality index. In addition, the species composition was observed to diversify throughout these oak stands’ development, thus supporting arguments for the conservation and preservation of oak-hornbeam forests. To summarise, the prerequisites for the success of the corridor method are systematic cuts of young stands (forest cultures and thickets) to inhibit the growth of accompanying undesired species and limiting the number of grazing animals.","PeriodicalId":35347,"journal":{"name":"USDA Forest Service - Research Papers PNW-RP","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78959088","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
Spatial variability of CO2 fluxes from meadow and forest soils in western part of Wzniesienia Łódzkie (Łódź Hills) Wzniesienia西部草甸和森林土壤CO2通量的空间变异性Łódzkie (Łódź Hills)
USDA Forest Service - Research Papers PNW-RP Pub Date : 2018-03-01 DOI: 10.2478/frp-2018-0006
K. T. Wroński
{"title":"Spatial variability of CO2 fluxes from meadow and forest soils in western part of Wzniesienia Łódzkie (Łódź Hills)","authors":"K. T. Wroński","doi":"10.2478/frp-2018-0006","DOIUrl":"https://doi.org/10.2478/frp-2018-0006","url":null,"abstract":"Abstract For this study, the rate of soil respiration was estimated based on monthly measurements of 20 research points representing different types of plant communities. Meadows were found to have the highest rates of soil respiration, whereas rates measured in forests were lower. However, the seasonality of leaf and pine needle decomposition caused large variation in the CO2 fluxes from forest soils. Furthermore, the carbon content at both, the soil surface and 5 cm below ground, affected spatial differentiation of soil respiration in summer and autumn, while the carbon content at 5 cm below ground also affects the spatial variability of annual CO2 fluxes from the soil. Amazingly, however, results of research indicate that the carbon content throughout the whole humus layer does not impact soil respiration. It was also observed that changes in relief affected rates of soil respiration due to differences in sunlight exposure and the history of land use, which can markedly reduce the impact of the carbon content at 5 cm below ground on soil respiration.","PeriodicalId":35347,"journal":{"name":"USDA Forest Service - Research Papers PNW-RP","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89621096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 3
The influence of atmospheric light scattering on reflectance measurements during photogrammetric survey flights at low altitudes over forest areas 森林地区低空摄影测量飞行期间大气光散射对反射率测量的影响
USDA Forest Service - Research Papers PNW-RP Pub Date : 2018-03-01 DOI: 10.2478/frp-2018-0007
A. Mazur, M. Kacprzak, K. Kubiak, J. Kotlarz, K. Skocki
{"title":"The influence of atmospheric light scattering on reflectance measurements during photogrammetric survey flights at low altitudes over forest areas","authors":"A. Mazur, M. Kacprzak, K. Kubiak, J. Kotlarz, K. Skocki","doi":"10.2478/frp-2018-0007","DOIUrl":"https://doi.org/10.2478/frp-2018-0007","url":null,"abstract":"Abstract In this article, we describe methods for the correction of multispectral aerial images by accounting for atmospheric interference. We also summarize the first correction results for images acquired at flight altitudes and evaluate the suitability of selected methods for the atmospheric correction of these images. Furthermore, processes and phenomena occurring in the atmosphere that potentially affect image quality and interfere with the electromagnetic radiation registered by the imaging sensors are discussed as well. The purpose of atmospheric correction is to reduce or eliminate atmospheric interference during multispectral image processing. Here we present methodology for image correction based on data gathered at various altitudes during the autumn flights conducted as a part of the HESOFF project.","PeriodicalId":35347,"journal":{"name":"USDA Forest Service - Research Papers PNW-RP","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82383435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 4
Assessment of sea buckthorn (Hippophaë rhamnoides L.) long distance dispersal on the internal waste heap of the Bełchatów lignite mine 沙棘(Hippophaë rhamnoides L.)在Bełchatów褐煤矿山内部垃圾堆上长距离扩散的评价
USDA Forest Service - Research Papers PNW-RP Pub Date : 2018-03-01 DOI: 10.2478/frp-2018-0001
L. Bolibok, M. Kubiak, S. Michalski
{"title":"Assessment of sea buckthorn (Hippophaë rhamnoides L.) long distance dispersal on the internal waste heap of the Bełchatów lignite mine","authors":"L. Bolibok, M. Kubiak, S. Michalski","doi":"10.2478/frp-2018-0001","DOIUrl":"https://doi.org/10.2478/frp-2018-0001","url":null,"abstract":"Abstract Long distance dispersal is a key process occurring in plant communities and is particularly important for pioneer species like sea-buckthorn (Hippophaë rhamnoides L.) which survival strongly depends on colonizing newly created post-disturbance habitats. Sea-buckthorn, a cluster-forming shrub, is commonly used in Poland in the reclamation of soil-less areas devastated the by mining industry and for these areas a generative expansion of planted populations is usually observed. The main objective of this study was to assess the long-distance dispersal of this species in areas previously disturbed by industrial activity. Our observations were made on a 223.75 ha large section of the internal waste heap of the Bełchatów lignite mine, Central Poland. The area was colonized by sea-buckthorn specimens originating from a population planted on the nearby external waste heap. During the search for newly established sea-buckthorn clusters, their position and size were recorded and the preferences for specific site conditions were assessed using the Ivlev’s electivity index. New specimen were observed at distances between 600 m and 3600 m from their potential seed source. The mean cluster density was 1.37 ha−1. The observed pattern of long distance dispersal is linked with to behavior of frugivorous birds. The largest cluster densities were observed along ditches (9.83 ha−1) and on open areas with less developed plant cover, while the lowest cluster density occurred in afforested areas (0.51 ha−1). Poor sandy substrate reduced the probability of plant establishment compared to richer loamy sands. There appeared to be no influence of slope aspect on the probability of sea-buckthorn establishment.","PeriodicalId":35347,"journal":{"name":"USDA Forest Service - Research Papers PNW-RP","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74759365","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
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