To test the feasibility of radiant energy vacuum （REV） dehydration, a technology that couples microwave cooking with vacuum pressure, on beef jerky preparation, the physical and microbial properties of the final jer...To test the feasibility of radiant energy vacuum （REV） dehydration, a technology that couples microwave cooking with vacuum pressure, on beef jerky preparation, the physical and microbial properties of the final jerky product was compared to conventional preparation methods. Physical characteristics assessed using puncture and shear tests of samples prepared using REV dehydration compared to the traditional method were not statistically different （P 〈 0.05）. Moisture content and water activity levels were also very similar between the two products, To test microbiological quality, samples were homogenized in a stomacher and a variety of 3 M Petrifilms were used to evaluate the microbial load. Raw beef harboured low numbers of microbes, but the post-marination pasteurization/smoking step used in both treatments eliminated all culturable microorganisms tested for. To further investigate the ability of REV dehydration to kill microbes, samples were spiked with Listeria innocua after the pasteurization/smoking step but prior to REV dehydration. Samples were taken at different time intervals for microbial enumeration, and a decimal reduction time of 1 min was calculated, with 99.99% of 1.98 × 10^7 CFU g^-1 Listeria being killed in five min. Improved drying times were observed for jerky samples prepared using the REV method offering potential energy savings during jerky preparation.展开更多
Mangrove forests in southern Iran are of high ecological and economic importance.These forests are being threatened because of uncontrolled harvesting to provide fodder for livestock.The objective of this study is to ...Mangrove forests in southern Iran are of high ecological and economic importance.These forests are being threatened because of uncontrolled harvesting to provide fodder for livestock.The objective of this study is to provide recommendations for appropriate harvesting intensities by quantifying the effect of different harvesting intensities on vegetative and vigor characteristics of mangrove trees.This study was conducted using a randomized complete block design comprising four treatments(10.00%,20.00%,and 30.00% trimming,along with a control)replicated three times.Vegetative characteristics were measured before and after trimming(five-year period)and analyzed using generalized linear model statistical analysis.The growths of the average diameter of canopy,canopy area,canopy volume,canopy height,tree height,and collar diameter in the control treatment were all significantly higher than those in the trimming treatments.In addition,there was a decreasing trend in leaf fresh and dry mass,leaf area index,total area of canopy leaves,and health status of tree in the trimming treatments.For example,the percentage change in fresh and dry leaf mass in the control treatment was positive(29.87% and 38.31%,respectively),whereas the trimming treatments of 10.00%,20.00% and 30.00% had negative effects(-7.01% and -4.79%,-11.32% and -14.30%,and -15.84% and -17.29%,respectively).In addition,the changes in leaf area index in the control(4.95%)and 30.00% trimming(-24.57%)treatments were the highest and lowest,respectively.The percentage change in soil organic matter in the control,10.00%,20.00%,and 30.00% treatments were 22.94%,-9.90%,-16.91%,and -18.68%,respectively.The study demonstrated that gray mangrove trees were highly sensitive to canopy trimming,with even minimal trimming intensities negatively affecting vegetative growth and soil organic matter.Therefore,it is recommended that cutting and trimming of mangrove trees should be prevented even at low intensity to preserve mangrove ecosystem health and resilience against enviro展开更多
We propose a nonparametric change point estimator in the distributions of a sequence of independent observations in terms of the test statistics given by Huˇskov′a and Meintanis(2006) that are based on weighted empi...We propose a nonparametric change point estimator in the distributions of a sequence of independent observations in terms of the test statistics given by Huˇskov′a and Meintanis(2006) that are based on weighted empirical characteristic functions. The weight function ω(t; a) under consideration includes the two weight functions from Huˇskov′a and Meintanis(2006) plus the weight function used by Matteson and James(2014),where a is a tuning parameter. Under the local alternative hypothesis, we establish the consistency, convergence rate, and asymptotic distribution of this change point estimator which is the maxima of a two-side Brownian motion with a drift. Since the performance of the change point estimator depends on a in use, we thus propose an algorithm for choosing an appropriate value of a, denoted by a_s which is also justified. Our simulation study shows that the change point estimate obtained by using a_s has a satisfactory performance. We also apply our method to a real dataset.展开更多
Stemflow is a focused point source input of precipitation and nutrients at the base of a tree or plant and can have a significant impact on site hydrology. To date, no known studies have modelled stemflow production f...Stemflow is a focused point source input of precipitation and nutrients at the base of a tree or plant and can have a significant impact on site hydrology. To date, no known studies have modelled stemflow production for juvenile lodgepole pine （Pinus contorta vat. latifolia）. Meteorological conditions, tree characteristics, and stemflow were sampled for two juvenile lodgepole pine stands over the course of the 2009 growing season. Step-wise multiple regression was used to assess which meteorological and tree architecture variables influenced stemflow production for each research plot. Once predictor variables were identified, models were produced for each stand and a generic model was produced that applied to both plots. A model employing precipitation depth and crown projection area successfully explained 71.3% of the variation in stemflow production from sampled trees. Stemflow was found to represent 1.8% of the study period rainfall and, although not a large component of the plot-scale canopy water balance, it is an order of magnitude greater than the fractioning of stemflow from mature lodgepole and lodgepole pine dominated forest. Additionally, stemflow funnelling ratios were found to average 22.2 and 24.3 from the two sample plots over the study period with a single tree, single event maximum of 111.7 recorded for a tree with a 3.3 cm bole diameter and a rain depth of 17.4 mm.展开更多
Rainfall, throughfall and stemflow were measured and canopy interception loss was derived for 14 rainfall events from June 22 to August 30, 2008 within a mature declining hybrid white spruce （Picea glauca （Moench） ...Rainfall, throughfall and stemflow were measured and canopy interception loss was derived for 14 rainfall events from June 22 to August 30, 2008 within a mature declining hybrid white spruce （Picea glauca （Moench） Voss x p engelmannii Parry ex Engelm.） - subalpine fir （Abies lasiocarpa （Hook.） Nutt.） - lodgepole pine （Pinus contorta vat. latifolia Dougl. ex Loud.） stand in south-central British Columbia, Can- ada. Stemflow was negligible during the study period, while, respectively throughfall and canopy interception loss accounted for approximately 59.4% and 40.6% of the 50.1 mm of cumulative rainfall. Throughfall variability was assessed with three approaches involving roving and stationary wedge-type gauges, and stationary trough gauges. Throughfall exhibited large spatial variability with the coefficient of variability of study period throughfall sampled using 16 stationary trough gauges being 30.3%, while it was 38.0% and 28.7% for 32 stationary and 32 roving wedge gauges, respectively. Our analysis suggests that a roving gauge method is better than a stationary approach since the errors associated with event mean throughfalls are summed quadratically and a greater portion of the canopy area is sampled. Trough gauges were more efficient than wedge gauges; however, this efficiency was less than expected given their much larger sampling areas, suggesting that spatial autocorrelation lengths of throughfall may be longer than the trough systems. The spatial distribution of throughfall showed a high degree of temporal persistence throughout the study suggesting the existence of stable ＂wet＂ and ＂dry＂ inputs to the floors of these coniferous forests.展开更多
Atmospheric pollution is an important concern in urban environments.The impact of urban pollution on the physiological,biochemical and anatomical properties of leaves of oriental plane(Platanus orientalis L.)was studi...Atmospheric pollution is an important concern in urban environments.The impact of urban pollution on the physiological,biochemical and anatomical properties of leaves of oriental plane(Platanus orientalis L.)was studied.The leaves were collected from an urban site(Tehran,Iran)and a non-urban forest park(Chitgar Forest Park).Anatomical(stomata,parenchyma,and cuticle)and physiological(chlorophyll content,enzyme activities)properties were analyzed.The concentrations of Cd(cadmium),Pb(lead),Ni(nickel),and Cr(chromium)in leaves were significantly higher and Zn(zinc)lower at the urban site relative to the forest park.Chlorophyll a,total chlorophyll,and carotenoid content in leaves of the urban site were significantly less than those of the forest park,but there was no significant difference in chlorophyll b.In addition,the activities of superoxide dismutase,catalase,ascorbate peroxidase,and guaiacol peroxidase in urban leaves were significantly higher than in the leaves of the forest park.In the urban area,leaves experienced a significant decrease in leaf surface area,stomata density,stomata pore area,epidermis,and spongy mesophyll thickness,but a significant increase in cuticle and palisade thicknesses relative to forest park leaves.The increase in enzyme activities may indicate that the trees are attempting to cope with increased reactive oxygen species(ROS)because of pollution-induced stress.Our study suggests that oriental plane trees alter their physiological and anatomical properties when living in a polluted urban environment.展开更多
Non-Orthogonal Multiple Access(NOMA)has emerged as a novel air interface technology for massive connectivity in Sixth-Generation(6G)era.The recent integration of NOMA in Backscatter Communication(BC)has triggered sign...Non-Orthogonal Multiple Access(NOMA)has emerged as a novel air interface technology for massive connectivity in Sixth-Generation(6G)era.The recent integration of NOMA in Backscatter Communication(BC)has triggered significant research interest due to its applications in low-powered Internet of Things(IoT)networks.However,the link security aspect of these networks has not been well investigated.This article provides a new optimization framework for improving the physical layer security of the NOMA ambient BC system.Our system model takes into account the simultaneous operation of NOMA IoT users and the Backscatter Node(BN)in the presence of multiple EavesDroppers(EDs).The EDs in the surrounding area can overhear the communication of Base Station(BS)and BN due to the wireless broadcast transmission.Thus,the chief aim is to enhance link security by optimizing the BN reflection coefficient and BS transmit power.To gauge the performance of the proposed scheme,we also present the suboptimal NOMA and conventional orthogonal multiple access as benchmark schemes.Monte Carlo simulation results demonstrate the superiority of the NOMA BC scheme over the pure NOMA scheme without the BC and conventional orthogonal multiple access schemes in terms of system secrecy rate.展开更多
James E.Lovelock,famed for his Gaia hypothesis,which views the Earth as a living integrated and interconnected self-regulating system whose equilibrium comes about from complex energy-based interactions and feedback l...James E.Lovelock,famed for his Gaia hypothesis,which views the Earth as a living integrated and interconnected self-regulating system whose equilibrium comes about from complex energy-based interactions and feedback loops,ultimately sustaining life,passed away at the end of July,2022 at the age of 103.Not only are the adaptive mechanisms of Gaia central to the conversation of environmental homeostasis,they lie at the heart of climate change and global warming.Lovelock is also remembered as the co-inventor of the electron capture detector that eventually allowed for the sensitive detection of chlorofluorocarbons and pesticides.Finally,Lovelock’s free-spirited nature and research independence allow academia to rethink current research’s modus operandi.展开更多
A （δ, g）-cage is a δ-regular graph with girth g and with the least possible number of vertices. In this paper, we show that all （δ, g）-cages with odd girth g ≥ 9 are r-connected, where （r - 1）2 ≤δ ＋ x/δ ...A （δ, g）-cage is a δ-regular graph with girth g and with the least possible number of vertices. In this paper, we show that all （δ, g）-cages with odd girth g ≥ 9 are r-connected, where （r - 1）2 ≤δ ＋ x/δ - 2 〈 r2 and all （δ, g）-cages with even girth g 〉 10 are r-connected, where r is the largest integer satisfying r（r-1）2/4 ＋ 1 ＋ 2r（r - 1） ≤δ. These results support a conjecture of Fkl, Huang and Rodger that all （δ, g）-cages are 6-connected.展开更多
The growth of the software game development industry is enormous and is gaining importance day by day. This growth imposes severe pressure and a number of issues and challenges on the game development community. Game ...The growth of the software game development industry is enormous and is gaining importance day by day. This growth imposes severe pressure and a number of issues and challenges on the game development community. Game development is a complex process, and one important game development choice is to consider the developer＇s perspective to produce good-quality software games by improving the game development process. The objective of this study is to provide a better understanding of the developer＇s dimension as a factor in software game success. It focuses mainly on an empirical investigation of the effect of key developer＇s factors on the software game development process and eventually on the quality of the resulting game. A quantitative survey was developed and conducted to identify key developer＇s factors for an enhanced game development process. For this study, the developed survey was used to test the research model and hypotheses. The results provide evidence that game development organizations must deal with multiple key factors to remain competitive and to handle high pressure in the software game industry. The main contribution of this paper is to investigate empirically the influence of key developer＇s factors on the game development process.展开更多
In this paper, we investigate the existence of [a,b]-factors with inclusion/exclusion properties under the toughness condition. We prove that if an incomplete graph G satisfies t(G) (a-1) + ab and a,b are two integers...In this paper, we investigate the existence of [a,b]-factors with inclusion/exclusion properties under the toughness condition. We prove that if an incomplete graph G satisfies t(G) (a-1) + ab and a,b are two integers with b > a > 1, then for any two given edges e1 and e2, there exist an [a,b]-factor including e1,e2; and an [a,b]-factor including e1 and excluding e2; as well as an [a,b]-factor excluding e1,e2 unless e1 and e2 have a common end in the case of a = 2. For complete graphs, we obtain a similar result.展开更多
Interval hypermatrices(tensors)ape introduced and interval α-hypermatrices are uniformly characterized using a finite set of'extreme'hypermatrices,where α can be strong P,semi-positive,or positive definite,a...Interval hypermatrices(tensors)ape introduced and interval α-hypermatrices are uniformly characterized using a finite set of'extreme'hypermatrices,where α can be strong P,semi-positive,or positive definite,among many others.It is shown that a symmetric interval is an interval(strictly)copositive-hypermatrix if and only if it is an interval(E)Eo-hypermatrix.It is also shown that an even-order,symmetric interval is an interval positive(semi-)definite-hypermatrix if and only if it is an interval P(P_(0))-hypermatrix.Interval hypermnatrices are generalized to sets of hyper-matrices,several slice-properties of a set of hypermatrices are introduced and sets of hypermatrices with various slice-properties are uniformly characterized.As a consequence,several slice-properties of a compact,convex set of hyper-matrices are characterized by its extreme points.展开更多
The Fort Worth （Texas） exhibition/publication Poussin： The Early Years in Rome： The Origins of French Classicism （1988） proved to be a seminal event in Poussin scholarship. Over 200 works were put on display at ...The Fort Worth （Texas） exhibition/publication Poussin： The Early Years in Rome： The Origins of French Classicism （1988） proved to be a seminal event in Poussin scholarship. Over 200 works were put on display at the Kimbell Art Museum that revealed the formative years in the French painter＇s works. The drawings and paintings confirmed Poussin as the leading classicist in 17th century French art and expanded our appreciation of the flexibility of the artist to illustrate mythological narratives. Previous positions on the artist such as Anthony Blunt＇s, who viewed the painter as a strict classicist without a major interest in color, are now reevaluated after the Fort Worth show. The influence of the Venetian school, especially the work of Titian, emerged stronger into Poussin＇s oeuvre. It was under the classicist umbrella that the romantic verse of Ovid and the sensual color of Titian became forged into the pictures of Roman mythology. The leading source of inspiration for this work would be Ovid＇s Metamorphoses where figures change into flowers made timeless by the painter＇s brush. Just as the poet varied the structure of his narrative presentation, so too did the painter expand his approach to depicting scenes of change in a variety of formats. A key work for Poussin in these stories of change would be the Kingdom of Flora （1631） where Ovidian tales are posed as an eternal spring where the goddess distributes the flowers of the collective narrative in an olive green chitin. This paper will contribute to the position of viewing Poussin＇s art under a wider vision of classicism where flexible narrative design and sensuous color fit the mission to make art noble and timeless.展开更多
A method for placing oil paint in metal tubes occurred in the early 1840s, which facilitated artists taking their materials out of doors to paint nature directly. In France in the 1860s, we know of painters like Claud...A method for placing oil paint in metal tubes occurred in the early 1840s, which facilitated artists taking their materials out of doors to paint nature directly. In France in the 1860s, we know of painters like Claude Monet were working on beaches and port cities to capture the effect of scenes under natural light. By 1874 the Anonymous Society of Painters, Sculptors, Engravers, etc. （Impressionists） offered their first public exhibition to much criticism. A common complaint of the new work was that it lacked finish to be considered as a completed work for sale. It is the view of this paper that outdoor, or plein air painting, developed because of the circumstances this type of work developed in the artist naturally. I focus on two areas that outdoor painting forced the artist to consider： incidents and accidents. The incidents refer to the varied weather the painter had to deal with and the accidents identify the intuitive methods the plein air painters fell practice to when confronted by difficult passages or situations in nature. These experiences would shift the focus of the Impressionists from recording nature in a naturalistic way to self-expression, which would become a key idea in early modem painting. The finish the detractors of Impressionism called for would be replaced by an appreciation for the personal in painting as exacting images of landscape became predictable and lacked the vitality of the intuitive picture that could offer something new to art.展开更多
In Early 20th century,Canadian landscape painting had its roots in European art,especially in impressionism and subsequent developments.When Claude Monet took to working in a series to capture changing light,he sought...In Early 20th century,Canadian landscape painting had its roots in European art,especially in impressionism and subsequent developments.When Claude Monet took to working in a series to capture changing light,he sought to simplify his subject;the painter would focus on a motif:a passage of river,a tree,or a building facade.This editing out of landscape information led to a more abstract work where one might focus on the color or brushwork in the painting.This method led to a release from the task of measuring for accuracy for the viewer.Painting became sensory and not imitative where one was free to enjoy pure painting that spoke directly to a sensation or a delight in an unsuspected arrangement.At the end of the 19th century,Art Nouveau designs were printed in international journals,like The Studio and were studied in commercial design shops,like Grip Ltd.,Toronto.The nucleus of Canada’s leading painting group―the Group of Seven,was formed out of commercial art and,to some extent,designs one could see reproduced in magazines.Tom Thomson took these motifs;these abstracted forms and envisioned them in the landscape of Ontario through his plein air sketches.Lawren Harris stylized trees and mountain forms into abstractions of pure delight and A.Y.Jackson set his hills in the landscapes of rural Quebec where repeating rhythms trumped topography accuracy.This paper will highlight these Canadian painters as they introduced the motif that moved landscape painting to decoration of the most satisfying kind.展开更多
Globalization is a topic much discussed today with the explosion of cell phones and instant messaging. This exchange of information causes the art historian to ponder the speed with which ideas spread in past centurie...Globalization is a topic much discussed today with the explosion of cell phones and instant messaging. This exchange of information causes the art historian to ponder the speed with which ideas spread in past centuries. The eighteenth was a century of colonial expansion made possible through the ships that sailed the great oceans Sea travel between Europe and North America drastically increased the spread of populations and their ideas between the old and new world. A good way to trace the exchange of ideas in picture painting in the eighteenth century would be to follow an artist like Benjamin West from his Quaker background in Pennsylvania to the center of the neoclassical style in Rome and a prolific career in London at the Royal Academy. West＇s travels and career offer an example of how an American pursued the artistic style of contemporary Rome to make images of North American history from a base in England. It was globalization eighteenth-century-style made possible by an ambitious artist connecting across the sea-lanes of international travel展开更多
The First World War did more to disrupt lives and reshape Canadian communities than any event in the short history of that country. Out on the prairies, cities and towns sent volunteer citizens to fight for Canada and...The First World War did more to disrupt lives and reshape Canadian communities than any event in the short history of that country. Out on the prairies, cities and towns sent volunteer citizens to fight for Canada and the British Empire with memorable success in the Great War. By the 1920s, the communities of Saskatchewan looked to mark the achievements of their soldiers overseas, who did not come home, with war memorials. These cenotaphs or ＂empty tombs＂ developed from Boer War models and London＇s Whitehall cenotaph completed for Armistice Day, 1920. The projects varied from simple cement plinths produced by prairie, stone workshops to the architect-commissioned memorial at Victoria Park, Regina. By the second half of the decade, cities from Saskatoon to Estevan, and towns soon to become cities, decorated their parks and streets with monuments that would become a focus of their community life and remembrance ceremonies for years to come. This paper will document those aspects of the city cenotaph in southern Saskatchewan in terms of community support, site and form selection and aspects of maintenance and the ongoing problem of vandalism, which frustrates city officials and Legion societies to this day.展开更多
As a study in art history critical theory, this paper looks at the appreciation and usage of art amongst interest groups at the time of the Great War and the subsequent legacy of the work of Canada＇s resident war art...As a study in art history critical theory, this paper looks at the appreciation and usage of art amongst interest groups at the time of the Great War and the subsequent legacy of the work of Canada＇s resident war artist Richard Jack. The Canadian War Museum＇s recent web page described Jack＇s standing officer in The Second Battle of Ypres 22 April to 25 May 1915 as one who ＂exemplifies the courage and resolve of the inexperienced Canadians in their first major battle＂. This comment showed a marked contrast to the contemporary art critic Richard Cork who described the first of the Canadian war memorials paintings as ＂a clich6-ridden bandaged officer ... shamelessly catering to public sentiment＂. Given these disparate positions, the author attempts to explain the gulf between these points of view and subsequently make the case that art has a broad application that might make us cautious of viewing a given work without due consideration of the context of its making and future merits.展开更多
文摘To test the feasibility of radiant energy vacuum （REV） dehydration, a technology that couples microwave cooking with vacuum pressure, on beef jerky preparation, the physical and microbial properties of the final jerky product was compared to conventional preparation methods. Physical characteristics assessed using puncture and shear tests of samples prepared using REV dehydration compared to the traditional method were not statistically different （P 〈 0.05）. Moisture content and water activity levels were also very similar between the two products, To test microbiological quality, samples were homogenized in a stomacher and a variety of 3 M Petrifilms were used to evaluate the microbial load. Raw beef harboured low numbers of microbes, but the post-marination pasteurization/smoking step used in both treatments eliminated all culturable microorganisms tested for. To further investigate the ability of REV dehydration to kill microbes, samples were spiked with Listeria innocua after the pasteurization/smoking step but prior to REV dehydration. Samples were taken at different time intervals for microbial enumeration, and a decimal reduction time of 1 min was calculated, with 99.99% of 1.98 × 10^7 CFU g^-1 Listeria being killed in five min. Improved drying times were observed for jerky samples prepared using the REV method offering potential energy savings during jerky preparation.
文摘Mangrove forests in southern Iran are of high ecological and economic importance.These forests are being threatened because of uncontrolled harvesting to provide fodder for livestock.The objective of this study is to provide recommendations for appropriate harvesting intensities by quantifying the effect of different harvesting intensities on vegetative and vigor characteristics of mangrove trees.This study was conducted using a randomized complete block design comprising four treatments(10.00%,20.00%,and 30.00% trimming,along with a control)replicated three times.Vegetative characteristics were measured before and after trimming(five-year period)and analyzed using generalized linear model statistical analysis.The growths of the average diameter of canopy,canopy area,canopy volume,canopy height,tree height,and collar diameter in the control treatment were all significantly higher than those in the trimming treatments.In addition,there was a decreasing trend in leaf fresh and dry mass,leaf area index,total area of canopy leaves,and health status of tree in the trimming treatments.For example,the percentage change in fresh and dry leaf mass in the control treatment was positive(29.87% and 38.31%,respectively),whereas the trimming treatments of 10.00%,20.00% and 30.00% had negative effects(-7.01% and -4.79%,-11.32% and -14.30%,and -15.84% and -17.29%,respectively).In addition,the changes in leaf area index in the control(4.95%)and 30.00% trimming(-24.57%)treatments were the highest and lowest,respectively.The percentage change in soil organic matter in the control,10.00%,20.00%,and 30.00% treatments were 22.94%,-9.90%,-16.91%,and -18.68%,respectively.The study demonstrated that gray mangrove trees were highly sensitive to canopy trimming,with even minimal trimming intensities negatively affecting vegetative growth and soil organic matter.Therefore,it is recommended that cutting and trimming of mangrove trees should be prevented even at low intensity to preserve mangrove ecosystem health and resilience against enviro
基金supported by Natural Sciences and the Engineering Research Council of Canada (Grant No. 105557-2012)National Natural Science Foundation for Young Scientists of China (Grant No. 11201108)+1 种基金the National Statistical Research Plan Project (Grant No. 2012LZ009)the Humanities and Social Sciences Project from Ministry of Education of China (Grant No. 12YJC910007)
文摘We propose a nonparametric change point estimator in the distributions of a sequence of independent observations in terms of the test statistics given by Huˇskov′a and Meintanis(2006) that are based on weighted empirical characteristic functions. The weight function ω(t; a) under consideration includes the two weight functions from Huˇskov′a and Meintanis(2006) plus the weight function used by Matteson and James(2014),where a is a tuning parameter. Under the local alternative hypothesis, we establish the consistency, convergence rate, and asymptotic distribution of this change point estimator which is the maxima of a two-side Brownian motion with a drift. Since the performance of the change point estimator depends on a in use, we thus propose an algorithm for choosing an appropriate value of a, denoted by a_s which is also justified. Our simulation study shows that the change point estimate obtained by using a_s has a satisfactory performance. We also apply our method to a real dataset.
基金funded by a British Columbia Forest Investment Account-Forest Science Program(Project#Y091045)granta National Science and Engineering Research Council(NSERC)Discovery Grant awarded to DC-M
文摘Stemflow is a focused point source input of precipitation and nutrients at the base of a tree or plant and can have a significant impact on site hydrology. To date, no known studies have modelled stemflow production for juvenile lodgepole pine （Pinus contorta vat. latifolia）. Meteorological conditions, tree characteristics, and stemflow were sampled for two juvenile lodgepole pine stands over the course of the 2009 growing season. Step-wise multiple regression was used to assess which meteorological and tree architecture variables influenced stemflow production for each research plot. Once predictor variables were identified, models were produced for each stand and a generic model was produced that applied to both plots. A model employing precipitation depth and crown projection area successfully explained 71.3% of the variation in stemflow production from sampled trees. Stemflow was found to represent 1.8% of the study period rainfall and, although not a large component of the plot-scale canopy water balance, it is an order of magnitude greater than the fractioning of stemflow from mature lodgepole and lodgepole pine dominated forest. Additionally, stemflow funnelling ratios were found to average 22.2 and 24.3 from the two sample plots over the study period with a single tree, single event maximum of 111.7 recorded for a tree with a 3.3 cm bole diameter and a rain depth of 17.4 mm.
基金funded by a British Columbia Forest Investment Account,Forest Science Program(Project#Y091045)granta National Science and Engineering Research Council(NSERC)Discovery Grant awarded to DC-M
文摘Rainfall, throughfall and stemflow were measured and canopy interception loss was derived for 14 rainfall events from June 22 to August 30, 2008 within a mature declining hybrid white spruce （Picea glauca （Moench） Voss x p engelmannii Parry ex Engelm.） - subalpine fir （Abies lasiocarpa （Hook.） Nutt.） - lodgepole pine （Pinus contorta vat. latifolia Dougl. ex Loud.） stand in south-central British Columbia, Can- ada. Stemflow was negligible during the study period, while, respectively throughfall and canopy interception loss accounted for approximately 59.4% and 40.6% of the 50.1 mm of cumulative rainfall. Throughfall variability was assessed with three approaches involving roving and stationary wedge-type gauges, and stationary trough gauges. Throughfall exhibited large spatial variability with the coefficient of variability of study period throughfall sampled using 16 stationary trough gauges being 30.3%, while it was 38.0% and 28.7% for 32 stationary and 32 roving wedge gauges, respectively. Our analysis suggests that a roving gauge method is better than a stationary approach since the errors associated with event mean throughfalls are summed quadratically and a greater portion of the canopy area is sampled. Trough gauges were more efficient than wedge gauges; however, this efficiency was less than expected given their much larger sampling areas, suggesting that spatial autocorrelation lengths of throughfall may be longer than the trough systems. The spatial distribution of throughfall showed a high degree of temporal persistence throughout the study suggesting the existence of stable ＂wet＂ and ＂dry＂ inputs to the floors of these coniferous forests.
文摘Atmospheric pollution is an important concern in urban environments.The impact of urban pollution on the physiological,biochemical and anatomical properties of leaves of oriental plane(Platanus orientalis L.)was studied.The leaves were collected from an urban site(Tehran,Iran)and a non-urban forest park(Chitgar Forest Park).Anatomical(stomata,parenchyma,and cuticle)and physiological(chlorophyll content,enzyme activities)properties were analyzed.The concentrations of Cd(cadmium),Pb(lead),Ni(nickel),and Cr(chromium)in leaves were significantly higher and Zn(zinc)lower at the urban site relative to the forest park.Chlorophyll a,total chlorophyll,and carotenoid content in leaves of the urban site were significantly less than those of the forest park,but there was no significant difference in chlorophyll b.In addition,the activities of superoxide dismutase,catalase,ascorbate peroxidase,and guaiacol peroxidase in urban leaves were significantly higher than in the leaves of the forest park.In the urban area,leaves experienced a significant decrease in leaf surface area,stomata density,stomata pore area,epidermis,and spongy mesophyll thickness,but a significant increase in cuticle and palisade thicknesses relative to forest park leaves.The increase in enzyme activities may indicate that the trees are attempting to cope with increased reactive oxygen species(ROS)because of pollution-induced stress.Our study suggests that oriental plane trees alter their physiological and anatomical properties when living in a polluted urban environment.
文摘Non-Orthogonal Multiple Access(NOMA)has emerged as a novel air interface technology for massive connectivity in Sixth-Generation(6G)era.The recent integration of NOMA in Backscatter Communication(BC)has triggered significant research interest due to its applications in low-powered Internet of Things(IoT)networks.However,the link security aspect of these networks has not been well investigated.This article provides a new optimization framework for improving the physical layer security of the NOMA ambient BC system.Our system model takes into account the simultaneous operation of NOMA IoT users and the Backscatter Node(BN)in the presence of multiple EavesDroppers(EDs).The EDs in the surrounding area can overhear the communication of Base Station(BS)and BN due to the wireless broadcast transmission.Thus,the chief aim is to enhance link security by optimizing the BN reflection coefficient and BS transmit power.To gauge the performance of the proposed scheme,we also present the suboptimal NOMA and conventional orthogonal multiple access as benchmark schemes.Monte Carlo simulation results demonstrate the superiority of the NOMA BC scheme over the pure NOMA scheme without the BC and conventional orthogonal multiple access schemes in terms of system secrecy rate.
文摘James E.Lovelock,famed for his Gaia hypothesis,which views the Earth as a living integrated and interconnected self-regulating system whose equilibrium comes about from complex energy-based interactions and feedback loops,ultimately sustaining life,passed away at the end of July,2022 at the age of 103.Not only are the adaptive mechanisms of Gaia central to the conversation of environmental homeostasis,they lie at the heart of climate change and global warming.Lovelock is also remembered as the co-inventor of the electron capture detector that eventually allowed for the sensitive detection of chlorofluorocarbons and pesticides.Finally,Lovelock’s free-spirited nature and research independence allow academia to rethink current research’s modus operandi.
文摘A （δ, g）-cage is a δ-regular graph with girth g and with the least possible number of vertices. In this paper, we show that all （δ, g）-cages with odd girth g ≥ 9 are r-connected, where （r - 1）2 ≤δ ＋ x/δ - 2 〈 r2 and all （δ, g）-cages with even girth g 〉 10 are r-connected, where r is the largest integer satisfying r（r-1）2/4 ＋ 1 ＋ 2r（r - 1） ≤δ. These results support a conjecture of Fkl, Huang and Rodger that all （δ, g）-cages are 6-connected.
文摘The growth of the software game development industry is enormous and is gaining importance day by day. This growth imposes severe pressure and a number of issues and challenges on the game development community. Game development is a complex process, and one important game development choice is to consider the developer＇s perspective to produce good-quality software games by improving the game development process. The objective of this study is to provide a better understanding of the developer＇s dimension as a factor in software game success. It focuses mainly on an empirical investigation of the effect of key developer＇s factors on the software game development process and eventually on the quality of the resulting game. A quantitative survey was developed and conducted to identify key developer＇s factors for an enhanced game development process. For this study, the developed survey was used to test the research model and hypotheses. The results provide evidence that game development organizations must deal with multiple key factors to remain competitive and to handle high pressure in the software game industry. The main contribution of this paper is to investigate empirically the influence of key developer＇s factors on the game development process.
基金supported by Natural Sciences and Engineering Research Council of Canada (Grant No. 144073)Shandong University Visiting Scholar FundPCSIRT Project of the Ministry of Education of China
文摘In this paper, we investigate the existence of [a,b]-factors with inclusion/exclusion properties under the toughness condition. We prove that if an incomplete graph G satisfies t(G) (a-1) + ab and a,b are two integers with b > a > 1, then for any two given edges e1 and e2, there exist an [a,b]-factor including e1,e2; and an [a,b]-factor including e1 and excluding e2; as well as an [a,b]-factor excluding e1,e2 unless e1 and e2 have a common end in the case of a = 2. For complete graphs, we obtain a similar result.
基金The research of the second author was supported by the Natural Sciences and Engineering Research Council of Canada.
文摘Interval hypermatrices(tensors)ape introduced and interval α-hypermatrices are uniformly characterized using a finite set of'extreme'hypermatrices,where α can be strong P,semi-positive,or positive definite,among many others.It is shown that a symmetric interval is an interval(strictly)copositive-hypermatrix if and only if it is an interval(E)Eo-hypermatrix.It is also shown that an even-order,symmetric interval is an interval positive(semi-)definite-hypermatrix if and only if it is an interval P(P_(0))-hypermatrix.Interval hypermnatrices are generalized to sets of hyper-matrices,several slice-properties of a set of hypermatrices are introduced and sets of hypermatrices with various slice-properties are uniformly characterized.As a consequence,several slice-properties of a compact,convex set of hyper-matrices are characterized by its extreme points.
文摘The Fort Worth （Texas） exhibition/publication Poussin： The Early Years in Rome： The Origins of French Classicism （1988） proved to be a seminal event in Poussin scholarship. Over 200 works were put on display at the Kimbell Art Museum that revealed the formative years in the French painter＇s works. The drawings and paintings confirmed Poussin as the leading classicist in 17th century French art and expanded our appreciation of the flexibility of the artist to illustrate mythological narratives. Previous positions on the artist such as Anthony Blunt＇s, who viewed the painter as a strict classicist without a major interest in color, are now reevaluated after the Fort Worth show. The influence of the Venetian school, especially the work of Titian, emerged stronger into Poussin＇s oeuvre. It was under the classicist umbrella that the romantic verse of Ovid and the sensual color of Titian became forged into the pictures of Roman mythology. The leading source of inspiration for this work would be Ovid＇s Metamorphoses where figures change into flowers made timeless by the painter＇s brush. Just as the poet varied the structure of his narrative presentation, so too did the painter expand his approach to depicting scenes of change in a variety of formats. A key work for Poussin in these stories of change would be the Kingdom of Flora （1631） where Ovidian tales are posed as an eternal spring where the goddess distributes the flowers of the collective narrative in an olive green chitin. This paper will contribute to the position of viewing Poussin＇s art under a wider vision of classicism where flexible narrative design and sensuous color fit the mission to make art noble and timeless.
文摘A method for placing oil paint in metal tubes occurred in the early 1840s, which facilitated artists taking their materials out of doors to paint nature directly. In France in the 1860s, we know of painters like Claude Monet were working on beaches and port cities to capture the effect of scenes under natural light. By 1874 the Anonymous Society of Painters, Sculptors, Engravers, etc. （Impressionists） offered their first public exhibition to much criticism. A common complaint of the new work was that it lacked finish to be considered as a completed work for sale. It is the view of this paper that outdoor, or plein air painting, developed because of the circumstances this type of work developed in the artist naturally. I focus on two areas that outdoor painting forced the artist to consider： incidents and accidents. The incidents refer to the varied weather the painter had to deal with and the accidents identify the intuitive methods the plein air painters fell practice to when confronted by difficult passages or situations in nature. These experiences would shift the focus of the Impressionists from recording nature in a naturalistic way to self-expression, which would become a key idea in early modem painting. The finish the detractors of Impressionism called for would be replaced by an appreciation for the personal in painting as exacting images of landscape became predictable and lacked the vitality of the intuitive picture that could offer something new to art.
文摘In Early 20th century,Canadian landscape painting had its roots in European art,especially in impressionism and subsequent developments.When Claude Monet took to working in a series to capture changing light,he sought to simplify his subject;the painter would focus on a motif:a passage of river,a tree,or a building facade.This editing out of landscape information led to a more abstract work where one might focus on the color or brushwork in the painting.This method led to a release from the task of measuring for accuracy for the viewer.Painting became sensory and not imitative where one was free to enjoy pure painting that spoke directly to a sensation or a delight in an unsuspected arrangement.At the end of the 19th century,Art Nouveau designs were printed in international journals,like The Studio and were studied in commercial design shops,like Grip Ltd.,Toronto.The nucleus of Canada’s leading painting group―the Group of Seven,was formed out of commercial art and,to some extent,designs one could see reproduced in magazines.Tom Thomson took these motifs;these abstracted forms and envisioned them in the landscape of Ontario through his plein air sketches.Lawren Harris stylized trees and mountain forms into abstractions of pure delight and A.Y.Jackson set his hills in the landscapes of rural Quebec where repeating rhythms trumped topography accuracy.This paper will highlight these Canadian painters as they introduced the motif that moved landscape painting to decoration of the most satisfying kind.
文摘Globalization is a topic much discussed today with the explosion of cell phones and instant messaging. This exchange of information causes the art historian to ponder the speed with which ideas spread in past centuries. The eighteenth was a century of colonial expansion made possible through the ships that sailed the great oceans Sea travel between Europe and North America drastically increased the spread of populations and their ideas between the old and new world. A good way to trace the exchange of ideas in picture painting in the eighteenth century would be to follow an artist like Benjamin West from his Quaker background in Pennsylvania to the center of the neoclassical style in Rome and a prolific career in London at the Royal Academy. West＇s travels and career offer an example of how an American pursued the artistic style of contemporary Rome to make images of North American history from a base in England. It was globalization eighteenth-century-style made possible by an ambitious artist connecting across the sea-lanes of international travel
文摘The First World War did more to disrupt lives and reshape Canadian communities than any event in the short history of that country. Out on the prairies, cities and towns sent volunteer citizens to fight for Canada and the British Empire with memorable success in the Great War. By the 1920s, the communities of Saskatchewan looked to mark the achievements of their soldiers overseas, who did not come home, with war memorials. These cenotaphs or ＂empty tombs＂ developed from Boer War models and London＇s Whitehall cenotaph completed for Armistice Day, 1920. The projects varied from simple cement plinths produced by prairie, stone workshops to the architect-commissioned memorial at Victoria Park, Regina. By the second half of the decade, cities from Saskatoon to Estevan, and towns soon to become cities, decorated their parks and streets with monuments that would become a focus of their community life and remembrance ceremonies for years to come. This paper will document those aspects of the city cenotaph in southern Saskatchewan in terms of community support, site and form selection and aspects of maintenance and the ongoing problem of vandalism, which frustrates city officials and Legion societies to this day.
文摘As a study in art history critical theory, this paper looks at the appreciation and usage of art amongst interest groups at the time of the Great War and the subsequent legacy of the work of Canada＇s resident war artist Richard Jack. The Canadian War Museum＇s recent web page described Jack＇s standing officer in The Second Battle of Ypres 22 April to 25 May 1915 as one who ＂exemplifies the courage and resolve of the inexperienced Canadians in their first major battle＂. This comment showed a marked contrast to the contemporary art critic Richard Cork who described the first of the Canadian war memorials paintings as ＂a clich6-ridden bandaged officer ... shamelessly catering to public sentiment＂. Given these disparate positions, the author attempts to explain the gulf between these points of view and subsequently make the case that art has a broad application that might make us cautious of viewing a given work without due consideration of the context of its making and future merits.
