Pattern In Scale Research Articles

Designing Supply Chain Management Pattern in Small Scale Integrated Commercial Agriculture

Designing Supply Chain Management Pattern in Small Scale Integrated Commercial Agriculture

Microstructures in Iron-rich FeSi Alloys by First-principles Phase Field and Special Quasirandom Structure Methods

Coarse grained phase morphologies of iron-rich region of FeSi alloys at 1050 K are investigated by using first-principles phase field and special quasirandom structure methods without relying on any experimental or empirical information. From the free energy comparison, we find that, for the Si concentration less than 25 at%, a solid-solution-like homogeneous phase is most stable, although a random pattern in nm scale consisting of B2 Fe4–xSix and D03 Fe3Si phases may appear at 12.5 at% Si at somewhat lower temperatures. We make a conjecture that, around 12.5 at% Si, such a random pattern in nm scale is the origin of the zero magnetostriction and low magnetic anisotropy. This solves a long-standing problem of the experimentally observed zero magnetostriction at 6.5 wt% Si. On the other hand, for the Si concentration slightly larger than 25 at%, FeSi alloys prefer two-phase coexistence of the D03 Fe3Si phase and the B2 FeSi phase. All these findings are in good accordance with the available experimental evidence.

Human movement patterns of different racial-ethnic and economic groups in U.S. top 50 populated cities: What can social media tell us about isolation?

ABSTRACT Many studies have proven that human movement patterns are strongly impacted by individual socioeconomic and demographic background. While many efforts have been made on exploring the influences of age and gender on movement patterns using social media, this study aims to analyse and compare the movement patterns among different racial-ethnic and economic groups using social media (i.e. geotagged tweets) from the U.S. top 50 populated cities. Results show that there are significant differences in number of activity zones and median travel distance across cities and demographic groups, and that power-laws tend to be captured in both spatial and demographic aspects. Additionally, the analysis of outbound-city travels demonstrates that some cities have slightly stronger interaction with others, and that economically disadvantaged populations and racial-ethnic minorities are more restricted in long distance travels, indicating that their spatial mobility is more limited to the local scale. Lastly, an economically-segregated movement pattern is discovered – upper-class neighbourhoods are mostly visited by the upper-class, while lower-class neighbourhoods are mainly accessed by the lower-class – but some racial-ethnic groups can diversify this segregated pattern in the local scale.

Exploring urban risk reduction strategy based on spatial statistics and scenario planning

Cities with dense population are vulnerable to disasters as they may cause losses of human life and property. Mitigation is most effective for reducing the risks of communities as well as creating more resilient communities in cities. However, exploring the spatial prioritization for resources investment and evaluating the relative efficiency of different alternative risk reduction strategies are still challenges. In this study, we proposed an innovative methodology framework for exploring risk reduction strategies in large-scale urban areas. GIS spatial statistics technique is introduced to investigate global regional risk pattern as well as identify local risk hot spots in spatial scale, and scenario planning paradigm is used to explore the dynamically changing regional risk pattern and risk hot spots in temporal scale due to risk reduction. Moreover, scenario sets were developed to evaluate and analyze the effectiveness and cost of different alternative risk reduction strategies for trade-off. We then applied the methodology to a typical urban district of north China to demonstrate its utility. The results successfully obtained reveal the necessity of concerning dynamically changing nature of regional risk spatial pattern during the risk reduction process. The findings show that the methodology framework proposed in this study has potential to provide decision support for guiding future urban risk reduction and hazard mitigation planning. This work offers new perspectives and valuable demonstration on promoting urban risk management with the integration of emerging GIS spatial statistics and scenario planning technique.

أثر اختلاف نمطي الإبحار (المقيد/ الحر) للتصميم الإلکتروني لمقرر الدراسات الأسرية على تنمية التحصيل المعرفي والشغف الإلکتروني لدى طلاب کلية التربية

هدف البحث الحالي إلى التعرف على أثر اختلاف نمطي الإبحار (المقيد/ الحر) للتصميم الإلکتروني لمقرر الدراسات الأسرية على تنمية التحصيل المعرفي والشغف الإلکتروني لدى طلاب کلية التربية، وأجريت تجربة البحث على مجموعة من الطلاب بلغت (60) طالبا وطالبة، وتم توزيعهم على مجموعتين تجريبيتين المجموعة الأولى تدرس المقرر الإلکتروني بنمط الابحار الحر والمجموعة الثانية تدرس المقرر الإلکتروني بنمط الابحار المقيد، وتضمنت أدوات البحث اختبارا في التحصيل المعرفي، ومقياسا في الشغف الإلکتروني، وتم تطبيق الأدوات قبليا وبعديا على مجموعتي البحث وباستخدام الأساليب الإحصائية المناسبة، وأسفرت نتائج البحث الحالي عما يلي: عدم وجود فرق دال احصائيا بين متوسطي درجات طلاب المجموعة التجريبية الأولى التي تدرس مقرر الدراسات الاسرية الإلکتروني باستخدام نمط الابحار المقيد في، ودرجات المجموعة التجريبية الثانية التي تدرس بنمط الابحار الحر في اختبار التحصيل المعرفي . عدم وجود فرق دال احصائيا بين متوسطي درجات طلاب المجموعة التجريبية الأولى التى تدرس مقرر الدراسات الاسرية الالکتروني باستخدام نمط الابحار المقيد، ودرجات المجموعة التجريبية الثانية التي تدرس بنمط الابحار الحر فى مقياس الشغف الالکتروني. The effect of the difference in the design of (restricted / free) navigation pattern in the design of the electronic content of the family studies course on the development of the cognitive achievement and the electronic passion Abstract The aim of the current research is to identify the effect of the difference in the design of navigation pattern (restricted / free) in the design of the electronic content of the family studies course on the development of the cognitive aspect and electronic passion for students of the College of Education, and the research experiment was conducted on a sample of students amounted to (60) female and male student, They were distributed to two experimental groups, one of which studied the electronic course in a menu navigation pattern and the otherrestricted / freenavigation pattern, and the educational materials and research tools included a test in cognitive achievement, and a scale in electronic passion, and the tools were applied before and after using the appropriate statistical methods for research hypotheses and goals The results of the current research resulted in the following: 1- There are no statistically significant differences between the mean scores of students of the first experimental group that are taught using the restricted sailing pattern in the electronic family studies course, and the scores of the experimental group that are taught by the free sailing pattern in the cognitive achievement test. 2- There are no statistically significant differences between the mean scores of students of the first experimental group that are taught using the restricted navigation pattern in the electronic family studies course, and the scores of the second experimental group that are taught by the sailing pattern in the electronic passion scale.

Diffraction and interference pattern by 4f imaging system to determine the thin film magnetic properties

Determine the magnetic properties of thin film material using X-ray has been attracting enormous attention in recent years. In this work, we propose a simple method to determine base on 4F imaging system. The narrow slit is applied to produce diffraction pattern in the X-ray scale. The slit width variation is applied to numerically obeserve the Fraunhofer diffraction pattern sequential changes. To demonstrate the sensitivity of the method, the power distribution of the temporal observed patterns was also measured. The selection of the object shape also discussed for comprehensive discussion.

Analyzing land use characteristics of rural settlements on the urban fringe of Liangjiang New Area, Chongqing, China

The objective of this paper is to analyze land use characteristics of rural settlements in urban fringe so as to provide references for optimizing the regional distribution of rural settlements, consolidating rural settlements, and coordinating urban-rural integrated development. The methods of spatial statistical analysis, buffer analysis, Ripley's K function, kernel density analysis based on GIS (Geographic Information System) were used to analyze the characteristics of scale, spatial differentiation and spatial patterns of the rural settlements in Liangjiang New Area in Chongqing Municipality of China. The fractal dimension formula was also developed to reflect fractal feature of the rural settlements. The results show that, the scale of rural settlements in Liangjang New Area takes on distinct characteristics of spatial differentiation along with changes in elevation, gradient, location, geo-hazards distribution, and the like. The fractal characteristic of rural settlements has obvious regional variations subject to the 6 factors of location in the Liangjiang New Area. Overall, the worse the terrain conditions are, the larger the fractal dimension values become. The better the location conditions, the larger the fractal dimension values are. The spatial pattern in the township scale presents three kinds of distribution as being aggregated, uniform and random. In contract, the spatial pattern in the plaque scale displays a banding distribution from a general view with several aggregation zones centering on each town center. From the results, we can see that the characteristics of rural settlements in urban fringe are more complicated. For such kind of rural settlements in special regions, in the rural land consolidation more attention should be paid to improve the rural living environments and public services, as well as to promote the harmonious relationship between the urban and rural areas.

Global Honeybee Colony Trend is Positively Related to Crop Yields of Medium Pollination Dependence

Recent declination of pollinators especially honeybee population in different geographical locations could threaten agricultural productivity leading to food insecurity. In order to examine the impact of the ‘pollinator crisis’, we hypothesized that the level of pollinator-dependence among the crops would be a significant factor to influence the crop yield. We examined the relationship between honeybee (Apis mellifera) population as a major insect pollinator and crop yields with varying pollinator dependence in two different geographical scales, the continental scale and the country. Yield data of 60 crop systems with varying pollinator dependencies and the colony size of honey bee (i.e., the number of bee hives) in 5 continents (Asia, Europe, Africa, Australia and Americas) over the period of 1983-2013 were obtained from FAO database. We emphasised two Asian countries, for instance, Republic of Korea and India, considering socioeconomic development status to examine more closely the pattern in a finer scale. The temporal pattern of honeybee colony was categorized into three levels, increasing, decreasing and stable. Regression analysis showed that honeybee colony pattern was positively correlated with little, modest and great pollinator dependent crops but negatively correlated with essential pollinator dependent crops. In two Asian countries analyzed for this study, Republic of Korea and India showed the same pattern of honeybee colony increase but with different rates and densities. Increased yields observed in crops with medium pollination dependence could have resulted from the increase of honeybee hive numbers, but the yield change of essential pollination dependent crop seemed more related to the socioeconomic condition.

Antarctic Sea Ice Response to Weather and Climate Modes of Variability*

Abstract The relationship between climate modes and Antarctic sea ice is explored by separating the variability into intraseasonal, interannual, and decadal time scales. Cross-spectral analysis shows that geopotential height and Antarctic sea ice extent are most coherent at periods between about 20 and 40 days (the intraseasonal time scale). In this period range, where the atmospheric circulation and the sea ice extent are most tightly coupled, sea ice variability responds strongly to Rossby waves with the structure of the Pacific–South American (PSA) pattern. The PSA pattern in this time scale is not directly related to El Niño–Southern Oscillation (ENSO) or the southern annular mode (SAM), which have received much attention for explaining Antarctic sea ice variability. On the interannual time scale, ENSO and SAM are important, but a large fraction of sea ice variance can also be explained by Rossby wave–like structures in the Drake Passage region. After regressing out the sea ice extent variability associated with ENSO, the observed positive sea ice trends in Ross Sea and Indian Ocean during the satellite era become statistically insignificant. Regressing out SAM makes the sea ice trend in the Indian Ocean insignificant. Thus, the positive trends in sea ice in the Ross Sea and the Indian Ocean sectors may be explained by the variability and decadal trends of known interannual climate modes.

Superhydrophobicity of Textured Ceramic Coating for Corrosion Protection in Marine Applications – A Brief Review

Technology for surface protection in contact with seawater has been studied. It mainly focuses on the capability of superhydrophobicity characteristic. Currently, the application of superhydrophobicity in controlling corrosion problem in the marine environment is still new. The development of superhydrophobicity on the materials surface can be achieved by designing a specific texture pattern in micro-or nanometer scale for producing high roughness surface. This review paper is mainly on the laser technology for producing superhydrophobicity characteristic of materials surface. This technique offers the most control and precision over the produced geometry.

Population and hierarchical genetic structure of <i>Badis badis</i> (Hamilton-Buchanan, 1822) in sub-Himalayan Terai region of West Bengal, India.

Badis badis is a threatened ornamental freshwater fish in the Indian scenario. But the population genetic background of this ichthyofauna is largely unexplored in the eastern sub-Himalayan hotspot region of West Bengal state of India, known as the Terai. We have studied six populations from two major streams (Mahananda and Balason) of the region through RAPD fingerprinting. The allelic richness, Shannon’s Information index and a measure of evenness were calculated for each population. The SHE analysis revealed the change in diversity pattern in a spatial scale. Our results indicated that the allelic richness decreased and the evenness increased in the populations as the streams drained from higher to a lower altitude. The Nei’s genetic distance, genetic identity and UPGMA dendrogram revealed that the six populations formed two distinct groups. The principal component analysis also supported the UPGMA dendrogram. The pair-wise gene differentiation and gene flow between the populations showed the hierarchical genetic structure of Badis badis in the studied region.

Alterations in scale: Patterns of change in main street networks across time and space

This paper presents a morphological study of 100 main street networks from urban areas around the world. An expansion in the scale of main street networks was revealed using a unique heuristic visual method for identifying and measuring the lengths of main street segments from each of the study areas. Case studies were selected and grouped according to corresponding urban design paradigms, ranging from antiquity to present day. This research shows that the average lengths of main street segments from networks of historic (i.e. ancient, medieval, renaissance, baroque and industrial) and informal case studies are much smaller relative to those from networks of more contemporary case studies (i.e. Garden City, Radiant City and New Urbanism). This study provides empirical evidence in support of prior, observational claims suggesting a consistent pattern in the smaller scale of main street networks from traditional urban areas, termed the ‘400-metre rule’. Additionally, it makes the case for further empirical research into similarly recursive spatial patterns within other elements of urban form (i.e. plots, blocks, etc.) that, if discovered, could aid in future urban design efforts to help provide the framework for more ‘human-scale’ urban environments.

Regional scale atmospheric dispersion simulation of accidental releases of radionuclides from Fukushima Dai-ichi reactor

This paper presents the results of regional scale atmospheric dispersion simulation of accidental emission of radionuclides from the Fukushima Daiichi Reactor, Japan following the Tohoku earthquake and tsunami event on 11 March 2011. The objective was to study the temporal behaviour of plume trajectory, concentration, deposition and radiation dose pattern over an 80 km range around the reactor. The time-varying meteorological parameters during the release period were simulated with a multi-scale nested atmospheric model WRF ARW and the trajectory, plume dispersion were computed with Lagrangian Particle Dispersion models HYSPLIT, FLEXPART using the available information on accidental source term. The simulations indicated that the wind flow over Japan during the release period was driven by the large scale extra-tropical westerly waves and associated low pressure systems. In the lower levels, the flow was influenced by the local topography/sea breeze causing occasional landward wind shift on the east coast of Japan. Simulated airflow trajectories revealed that the plume stayed over the ocean by westerly winds on most days and the radioactivity dispersed over sea surface. Landward trajectories were found on a few days due to southeasterly, easterly and northeasterly flow (15–17, 19–21 March 2011) during which much of the radionuclides deposited over the land region. The hotspot of depositions occurred over east Pacific Ocean near to Japan. Over the land relatively high depositions were simulated in a narrow zone of 20 km width and 80 km length in the northwest sector in agreement with monitor data. Simulations showed wet depositions over the land to be higher than the dry depositions during 12–30 March due to occurrence of rainfall on some days. Comparison of activity deposition and air dose values with available observations confirmed that the plume pattern in a finer length scale around the site could be simulated realistically and agree with the measurements within the limitations of the uncertainty in source term.

Replication of a Thin Polydimethylsiloxane Stamp and Its Application to Dual-Nanoimprint Lithography for 3D Hybrid Nano/Micropatterns

This paper presents the fabrication of a thin and flexible polydimethylsiloxane (PDMS) stamp with a thickness of a few tens of um and its application to nanoimprint lithography (NIL). The PDMS material generally has a low elastic modulus and high adhesive characteristics. Therefore, after being treated, the thin PDMS stamp is easily deformed and torn, adhering to itself and other materials. This paper introduces the use of a metal ring around the flange of a thin PDMS stamp to assist with the handling of this material. A PDMS stamp with a motheye pattern in nanometer scale was inserted between a substrate and a microstamp with concave patterns in micrometer scale. Subsequently, three-dimensional (3D) hybrid nano/micropatterns were fabricated by pressing these two stamps and curing the resist. The fabricated hybrid patterns were measured and verified in both the microscale and nanoscale. The process, termed "dual NIL," can be applied to the fabrication of optical components or bio-sensors that require repetitive nanopatterns on micropatterns.

Auditory Time-Interval Perception as Causal Inference on Sound Sources

Perception of a temporal pattern in a sub-second time scale is fundamental to conversation, music perception, and other kinds of sound communication. However, its mechanism is not fully understood. A simple example is hearing three successive sounds with short time intervals. The following misperception of the latter interval is known: underestimation of the latter interval when the former is a little shorter or much longer than the latter, and overestimation of the latter when the former is a little longer or much shorter than the latter. Although this misperception of auditory time intervals for simple stimuli might be a cue to understanding the mechanism of time-interval perception, there exists no model that comprehensively explains it. Considering a previous experiment demonstrating that illusory perception does not occur for stimulus sounds with different frequencies, it might be plausible to think that the underlying mechanism of time-interval perception involves a causal inference on sound sources: herein, different frequencies provide cues for different causes. We construct a Bayesian observer model of this time-interval perception. We introduce a probabilistic variable representing the causality of sounds in the model. As prior knowledge, the observer assumes that a single sound source produces periodic and short time intervals, which is consistent with several previous works. We conducted numerical simulations and confirmed that our model can reproduce the misperception of auditory time intervals. A similar phenomenon has also been reported in visual and tactile modalities, though the time ranges for these are wider. This suggests the existence of a common mechanism for temporal pattern perception over modalities. This is because these different properties can be interpreted as a difference in time resolutions, given that the time resolutions for vision and touch are lower than those for audition.

Dry Etching of Nanosized Ge<SUB>1</SUB>Sb<SUB>2</SUB>Te<SUB>4</SUB> Patterns Using TiN Hard Mask for High Density Phase-Change Memory

Being able to pattern and etch chalcogenide materials in nanometer scale is essential for the integration of high density chalcogenide random access memory. We investigated dry etching methods for the patterning of Ge1Sb2Te4 films in CHF3/O2 gas mixture using reactive-ion etching system. The gas species CHF3/O2 can reach good etched features with smooth sidewall and a taper angle of 86 degrees. The nanosized Ge1Sb2Te4 patterns were defined by electron-beam lithography using hydrogen silsesquioxane as negative type e-beam resist. A hard mask of TiN, to which the selectivity of Ge1Sb2Te4 is as high as 12, was chosen for employing a CHF3/O2 gas mixture for Ge1Sb2Te4 etching. The Ge1Sb2Te4 line with width of 170 nm could be successfully obtained with good profiles and uniformity using these optimized patterning conditions, which could be very helpful for fabricating high density chalcogenide random access memory based on Ge1Sb2Te4.

Patterning of Ge 2Sb 2Te 5 phase change material using UV nano-imprint lithography

DRAM is the most commonly used memory due to many advantages such as high speed and easy manufacturability owing to its simple structure, but is volatile. On the other hand, flash memory is non-volatile, but has other disadvantages such as slow speed, short lifetime, and low endurance for repetitive data writing. Compared to DRAM and flash memory, PRAM (Phase-change Random Access Memory), which is a non-volatile memory using a reversible phase change between amorphous and crystalline state, has many advantages such as high speed, high sensing margin, low operating voltage, and is being pursed as a next generation memory. Being able to pattern and etch phase change memory in nanometer scale is essential for the integration of PRAM. This study uses the Nano-Imprint Lithography (NIL) for patterning the PRAM in nanometer scale which is believed to be a future lithography technology that will replace the conventional Photo Lithography. Si wafers coated with SiO 2 were used as substrates, and Ge 2Sb 2Te 5 (GST) films with the thicknesses of 100 nm were deposited by RF sputtering. Poly-benzylmethacrylate based polymer patterns were formed using NIL on the surface of GST films, and the GST films were etched using Cl 2/Ar plasma in an Oxford ICP (inductively coupled plasma) etcher.

프리즘 패턴의 기계적 절삭 가공

In recent, various shapes of pattern in micron or nano scale are adapted in many applications due to their good mechanical or optical properties. Light guide panel (LGP) of the LCD is one of important applications for micro pattern and micro prism shape is one of the typical patterns. The size of the surface patterns in most applications is decreasing to the order of micron or even under micron. On the other hand, the area to be patterned keeps enlarging. These two trends in patterned products require tooling micro patterns on large surface, which has still many technical problems to be solved mainly due to pattern size and the tooling area. In this study, we fabricated prism shape of patterns using diamond cutting tool on some metal core and plastic core like PMMA. Some cutting conditions were investigated including cutting force, cutting depth and speed for different core materials.

Study on the formation of square emission pattern in argon discharge

Stable square emission patterns are observed in argon discharge at atmospheric pressure by using a dielectric barrier discharge device with different lateral boundary conditions. The spatio-temporal dynamics of square pattern in nanosecond time scale is investigated. It is found that the square pattern is an interlacing of two oscillating square sublattices, which have time sequence inversion behavior. The influence of the wall charge distribution on the forming process and the spatio-temporal dynamics of the emission patterns is discussed.

The Spatial-temporal Dynamics Analysis of Landscape Pattern and Process in Watershed Scale:a Case Study of 1977-2000 in Siletz Basin, Oregon

在集水区尺度利用景观生态学的原理进行分析和管理是现代生态学与地理科学的一个重要课题.在人口增长和经济发展的压力下,集水区的格局和过程己受到人类活动越来越强烈地干扰.赛勒支盆地是一个典型的美国太平洋西北部沿海地区的集水区,本文以此为例,研宄了美国俄勒冈州中部集水区尺度的景观格局和过程在人类活动干扰下的时空动态.通过卫星遥感影像的应用,我们对1977年到2000年间赛勒支盆地土地覆盖的变化进行了检测.我们用陆地资源卫星1977年的多光谱影像(MSS), 1988年的专题影像(TM)' 2000年的增强专题影像(ETM+)高精度地定量分析了森林演替系列(如,演替后期的老针叶林和成熟针叶林,演替前期的年轻针叶林,以及更新的幼林）和其它土地覆盖类型的变化.景观的空间格局通过多种格局指数,例如,缀块指数、缀块形状复杂性指数、以及连接指数等进行了分析.同时,基于美国太平洋西北部主要森林类型和其它土地覆盖类型碳通量和碳贮量的空间数据库和文献资料,我们对 1977-2000年赛勒支盆地中的碳库及其在人类活动干扰下的变化作了测定.研宄结果揭示出,因为森林皆伐,老针叶林和成熟针叶林在1977-2000年间显著地减少,分别由占整个盆地土地覆盖面积的23%和12%, 减少为12%和7%;与此相反,年轻针叶林和无林地则分别从24%和5%增加为43%和14%.同时,因为采伐等干扰,留存的老针叶林和成熟针叶林空间分布格局的破碎度也迅速增加.集水区的碳收支在 1977-2000期间发生了巨大的变化.在收获干扰的压力下,在1977-2000年间,整个集水区的生态系统碳贮量从 17640797t 减少到 13405720t;净生态系统生产力(Net Ecosystem Production, NEP)由每年 100462tC 减少为每年76800tC.;The landscape ecology applied in the analysis and management of watershed is an important issue in modem ecology and geography. Because the population growth and economic development, the pattern and process of watershed influenced strongly by human activity. In this paper, we discussed the spatial-temporal dynamics of landscape pattern and process in watershed scale in central Oregon. Siletz basin is a typical watershed in US Pacific Northwest. The land cover change of Siletz basin between 1977 to 2000 was determined through the satellite remote sensed data application. We used the Landsat MSS of 1977, Landsat TM of 1988 and Landsat ETM+ of 2000 imagery to quantified the forest succession serial (e.g. late serial old and mature conifer forests, early serial young conifer and regeneration forests) and other land covers with high accuracy. The spatial pattern of landscape was analyzed through the multiple pattern metrics, for example, patchiness indices, patch shape complexity indices, and connectivity indices. Based on the spatial databases and literature data, we parameterized the carbon fluxes and stocks information for the forest types and other lands in the US Pacific Northwest, and estimated the carbon fluxes and stock pools and the dynamics from 1977 to 2000 as the anthropogenic disturbance. We revealed the changes of land cover are significant from 1977 to 2000. The old conifer and mature conifer forests decreased quickly as the clearcut logging. In 1977-2000 periods, the percentage of old conifer and mature conifer area in entire Siletz basin from 23% and 12% decreased to 12% and 7%, respectively. In contrast, the young conifer forest and non-forest land from 24% and 5% increased to 43% and 14%, respectively. The fragmentation of old and mature conifer forest spatial pattern increased quickly as the harvest disturbance between 1977 and 2000. Carbon budget also was found changed significantly between 1977 and 2000. The ecosystem carbon pool decreased from 17640797t to 13405720 t, Net Ecosystem Production (NEP), an indicator of carbon sink and source, we found the pool of NEP had been changed from 100462 t/a to 76800 t/a between 1977 and 2000 as the land cover alternated by harvest disturbance.