Ungulate browsing often impairs tree regeneration,thus preventing the achievement of economic or conservation goals.Forest ungulate management would thus benefit from a practical decision tool that facilitates method ...Ungulate browsing often impairs tree regeneration,thus preventing the achievement of economic or conservation goals.Forest ungulate management would thus benefit from a practical decision tool that facilitates method selection from a wide range of monitoring methods and indicators currently available.In this study,we first provide an overview of the different browsing-impact monitoring methods and indicators currently applied.We then present a newly developed decision matrix for method evaluation that can assist forest stakeholders in choosing the browsing-impact monitoring method best suited to their needs,based on the selected indicators.The first step involved two separate literature reviews to create an overview of the currently applied methods and to select the indicators best suited for measuring browsing impact.Three types of indicator groups with their respective parameters were considered important for method evaluation:browsing indicators(e.g.regeneration density,browsing incidents),performance indicators(e.g.expense,expertise)and data quality indicators(e.g.susceptibility to measurement errors).Subsequently,all parameters defined within each indicator group were categorised and a grade was assigned to each category.To create the final method-indicator matrix,each browsing-impact monitoring method received a grade for each parameter within all indicator groups,reflecting the specific advantages and disadvantages of implementing the respective parameter within a specific method.The utility of the matrix in selecting the most suitable monitoring method was then demonstrated using the example of Germany's national parks.Based on the weights added to the method-indicator matrix,as defined by national park representatives,and considering local requirements the nearest-tree method was favoured over the other two methods.This newly developed matrix provides a more scientific objectification of ungulate browsing-impact measures and can be easily used by forest managers to address their own requirements,based on a consideration of the advantages and disadvantages of the included methods.展开更多
Annual forage legumes are important components of livestock production systems in East Texas and the southeastern US. Forage legumes contribute nitrogen (N) to cropping systems through biological N fixation, and their...Annual forage legumes are important components of livestock production systems in East Texas and the southeastern US. Forage legumes contribute nitrogen (N) to cropping systems through biological N fixation, and their seasonal biomass production can be managed to complement forage grasses. Our research objectives were to evaluate both warm- and cool-season annual forage legumes as green manure for biomass, N content, ability to enhance soil organic carbon (SOC) and soil N, and impact on post season forage grass crops. Nine warm-season forage legumes (WSL) were spring planted and incorporated as green manure in the fall. Forage rye (Secale cereale L.) was planted following the incorporation of WSL treatments. Eight cool-season forage legumes (CSL) were fall planted in previously fallow plots and incorporated as green manure in late spring. Sorghum-sudangrass (Sorghum bicolor x Sorghum bicolor var. sudanense) was planted over all treatments in early summer after forage rye harvest and incorporation of CSL treatments. Sorghum-sudangrass was harvested in June, August and September, and treatments were evaluated for dry matter and N concentration. Soil cores were taken from each plot, split into depths of 0 to 15, 15 to 30 and 30 to 60 cm, and soil C and N were measured using combustion analysis. Nylon mesh bags containing plant samples were buried at 15 cm and used to evaluate decomposition rate of above ground legume biomass, including change in C and N concentrations. Mungbean (Vigna radiata L. [Wilczek]) had the highest shoot biomass yield (6.24 t DM ha<sup>-1</sup>) and contributed the most total N (167 kg∙ha<sup>-1</sup>) and total C (3043 kg∙ha<sup>-1</sup>) of the WSL tested. Decomposition rate of WSL biomass was rapid in the first 10 weeks and very slow afterward. Winter pea (Pisum sativum L. spp. sativum), arrow leaf clover (Trifolium vesiculosum Savi.), and crimson clover (Trifolium incarnatum L.) were the most productive CSL in this trial. Austrian winter pea produced 8.41 t DM ha<sup>-1</sup> with a total N yield of 319 kg N ha<sup>-1</sup> and total C production of 3835 kg C ha<sup>-1</sup>. The WSL treatments had only small effects on rye forage yield and N concentration, possibly due to mineralization of N from a large SOC pool already in place. The CSL treatments also had only minimal effects on sorghum-sudangrass forage production. Winter pea, arrow leaf and crimson clover were productive cool season legumes and could be useful as green manure crops. Mungbean and cowpea (Vigna unguiculata [L.] Walp.) were highly productive warm season legumes but may include more production risk in green manure systems due to soil moisture competition.展开更多
Similarity matching and this paper, a saliency-based information presentation are two matching algorithm is proposed key factors in information retrieval. In for user-oriented search based on the psychological studies...Similarity matching and this paper, a saliency-based information presentation are two matching algorithm is proposed key factors in information retrieval. In for user-oriented search based on the psychological studies on human perception, and major emphasis on the saliently similar aspect of objects to be compared is placed and thus the search result is more agreeable for users. After relevant results are obtained, the cluster-based browsing algorithm is adopted for search result presentation based on social network analysis. By organizing the results in clustered lists, the user can have a general understanding of the whole collection by viewing only a small part of results and locate those of major interest rapidly. Experimental results demonstrate the advantages of the proposed algorithm over the traditional work.展开更多
Among mobile users, ad-hoc social network (ASN) is becoming a popular platform to connect and share their interests anytime anywhere. Many researchers and computer scientists investigated ASN architecture, implementat...Among mobile users, ad-hoc social network (ASN) is becoming a popular platform to connect and share their interests anytime anywhere. Many researchers and computer scientists investigated ASN architecture, implementation, user experience, and different profile matching algorithms to provide better user experience in ad-hoc social network. We emphasize that strength of an ad-hoc social network depends on a good profile-matching algorithm that provides meaningful friend suggestions in proximity. Keeping browsing history is a good way to determine user’s interest, however, interests change with location. This paper presents a novel profile-matching algorithm for automatically building a user profile based on dynamic GPS (Global Positing System) location and browsing history of users. Building user profile based on GPS location of a user provides benefits to ASN users as this profile represents user’s dynamic interests that keep changing with location e.g. office, home, or some other location. Proposed profile-matching algorithm maintains multiple local profiles based on location of mobile device.展开更多
The passwords for unlocking the mobile devices are relatively simple,easier to be stolen,which causes serious potential security problems.An important research direction of identity authentication is to establish user...The passwords for unlocking the mobile devices are relatively simple,easier to be stolen,which causes serious potential security problems.An important research direction of identity authentication is to establish user behavior models to authenticate users.In this paper,a mobile terminal APP browsing behavioral authentication system architecture which synthesizes multiple factors is designed.This architecture is suitable for users using the mobile terminal APP in the daily life.The architecture includes data acquisition,data processing,feature extraction,and sub model training.We can use this architecture for continuous authentication when the user uses APP at the mobile terminal.展开更多
Jojoba is a desert shrub,introduced in the marginal areas of Kenya during 1980s.Jojoba domestication is being faced by browsing problems due to pastoralism in these areas.Massive browsing of leaves lowers photosynthes...Jojoba is a desert shrub,introduced in the marginal areas of Kenya during 1980s.Jojoba domestication is being faced by browsing problems due to pastoralism in these areas.Massive browsing of leaves lowers photosynthesis leading to decline in plant functions.An experiment was set up in Maungu,with the aim of determining the effect of browsing on jojoba seedlings.The experimental design was a randomized complete block design with three treatments replicated three times.The treatments consisted of varying levels of browsing as follows:non browsed,50%browsed and fully browsed.Seedlings were raised for six months before sampling.Variables assessed were:survival,height,root-collar diameter,leaf size,root length and number,internode length,sprout number,root/shoot ratio and total biomass.ANOVA was performed to determine differences among the treatments whilst significant differences among the means were separated using least significant difference(LSD)at p≤0.05.Results showed fully browsed seedlings were significantly lower in height(26.2 cm),internode length(9.7 mm),leaf length(18.3 mm)and width(10.4 mm)and total fresh plant biomass(11.0 g)compared to the non browsed ones which showed 31.1 cm,23.2,36.1 and 16.6 mm and 17.8 g,respectively.On the other hand,fully browsed seedlings showed significantly higher root/shoot ratio.Seedling growth was negatively affected by severity of browsing which resulted in stunted growth.The study recommended that browsing of seedlings should be prevented since it hinders plant growth.展开更多
Fire is regarded as management practice for maintaining grasslands and savannas. The vegetation occurring in fire prone areas becomes highly adapted to fire occurrences in savannas and grasslands. However, documentati...Fire is regarded as management practice for maintaining grasslands and savannas. The vegetation occurring in fire prone areas becomes highly adapted to fire occurrences in savannas and grasslands. However, documentation on the influence of burning on vegetation is still limited in an albany thicket biome. The aim of the study was to evaluate the short-term influence of burning on species abundance, biomass production, wood plant density and browsing unit. Six plots (2500 m<sup>2</sup>) were demarcated;in each plot two parallel transects of 120 m<sup>2</sup> with 5 m distance apart were measured. Three plots were burned in spring season, while no burning was done on the other remaining plots. Forty points per plot were obtained using step-point method to determine the relative abundance at burned and unburned plots. Woody plants occurred within a transect were identified, counted and recorded to determine density and browsing unit. Three quadrats (<em>i.e</em>. 0.25 m<sup>2</sup>) per plot were randomly laid within the transect;aboveground plant material within a quadrat were harvested. A total of 18 samples were harvested and oven dried at 60<span style="white-space:nowrap;"><span style="white-space:nowrap;">˚</span></span>C for 48 hours to determine biomass production. The results showed that <em>Themeda triandra</em> (14%) and <em>Panicum maximum</em> (10%) were most abundant grass species at the burned plots. Burned plots had significantly higher biomass production (4804 kg/ha) compared to unburned plots (3641 kg/ha). <em>Vachellia karoo</em> (burned: 65.85% & unburn: 13.70%) and <em>Searsia pallens </em>(burned: 26.83% & unburned: 6.85%) were most dominant wood plant species at both burned and unburned plots. Burned plots had the highest browsing unit (3221 BU/ha) compared to unburned plots (2058 BU/ha). The decrease of woody plants at the burned plots proved that fire has a tremendous potential for managing woody plants. This study provided information on short-term influence of burning, however further long-term trials are required to determine the effects of burning.展开更多
基金The present publication is a partial result of the R&D project‘Ungulate monitoring in German national parks’(FKZ:3518830200)which is supported by the Federal Agency for Nature Conservation(BfN).
文摘Ungulate browsing often impairs tree regeneration,thus preventing the achievement of economic or conservation goals.Forest ungulate management would thus benefit from a practical decision tool that facilitates method selection from a wide range of monitoring methods and indicators currently available.In this study,we first provide an overview of the different browsing-impact monitoring methods and indicators currently applied.We then present a newly developed decision matrix for method evaluation that can assist forest stakeholders in choosing the browsing-impact monitoring method best suited to their needs,based on the selected indicators.The first step involved two separate literature reviews to create an overview of the currently applied methods and to select the indicators best suited for measuring browsing impact.Three types of indicator groups with their respective parameters were considered important for method evaluation:browsing indicators(e.g.regeneration density,browsing incidents),performance indicators(e.g.expense,expertise)and data quality indicators(e.g.susceptibility to measurement errors).Subsequently,all parameters defined within each indicator group were categorised and a grade was assigned to each category.To create the final method-indicator matrix,each browsing-impact monitoring method received a grade for each parameter within all indicator groups,reflecting the specific advantages and disadvantages of implementing the respective parameter within a specific method.The utility of the matrix in selecting the most suitable monitoring method was then demonstrated using the example of Germany's national parks.Based on the weights added to the method-indicator matrix,as defined by national park representatives,and considering local requirements the nearest-tree method was favoured over the other two methods.This newly developed matrix provides a more scientific objectification of ungulate browsing-impact measures and can be easily used by forest managers to address their own requirements,based on a consideration of the advantages and disadvantages of the included methods.
文摘Annual forage legumes are important components of livestock production systems in East Texas and the southeastern US. Forage legumes contribute nitrogen (N) to cropping systems through biological N fixation, and their seasonal biomass production can be managed to complement forage grasses. Our research objectives were to evaluate both warm- and cool-season annual forage legumes as green manure for biomass, N content, ability to enhance soil organic carbon (SOC) and soil N, and impact on post season forage grass crops. Nine warm-season forage legumes (WSL) were spring planted and incorporated as green manure in the fall. Forage rye (Secale cereale L.) was planted following the incorporation of WSL treatments. Eight cool-season forage legumes (CSL) were fall planted in previously fallow plots and incorporated as green manure in late spring. Sorghum-sudangrass (Sorghum bicolor x Sorghum bicolor var. sudanense) was planted over all treatments in early summer after forage rye harvest and incorporation of CSL treatments. Sorghum-sudangrass was harvested in June, August and September, and treatments were evaluated for dry matter and N concentration. Soil cores were taken from each plot, split into depths of 0 to 15, 15 to 30 and 30 to 60 cm, and soil C and N were measured using combustion analysis. Nylon mesh bags containing plant samples were buried at 15 cm and used to evaluate decomposition rate of above ground legume biomass, including change in C and N concentrations. Mungbean (Vigna radiata L. [Wilczek]) had the highest shoot biomass yield (6.24 t DM ha<sup>-1</sup>) and contributed the most total N (167 kg∙ha<sup>-1</sup>) and total C (3043 kg∙ha<sup>-1</sup>) of the WSL tested. Decomposition rate of WSL biomass was rapid in the first 10 weeks and very slow afterward. Winter pea (Pisum sativum L. spp. sativum), arrow leaf clover (Trifolium vesiculosum Savi.), and crimson clover (Trifolium incarnatum L.) were the most productive CSL in this trial. Austrian winter pea produced 8.41 t DM ha<sup>-1</sup> with a total N yield of 319 kg N ha<sup>-1</sup> and total C production of 3835 kg C ha<sup>-1</sup>. The WSL treatments had only small effects on rye forage yield and N concentration, possibly due to mineralization of N from a large SOC pool already in place. The CSL treatments also had only minimal effects on sorghum-sudangrass forage production. Winter pea, arrow leaf and crimson clover were productive cool season legumes and could be useful as green manure crops. Mungbean and cowpea (Vigna unguiculata [L.] Walp.) were highly productive warm season legumes but may include more production risk in green manure systems due to soil moisture competition.
基金Supported by the Fund for Basic Research of National Non-Profit Research Institutes(No.XK2012-2,ZD2012-7-2)the Fund for Preresearch Project of ISTIC(No.YY201208)
文摘Similarity matching and this paper, a saliency-based information presentation are two matching algorithm is proposed key factors in information retrieval. In for user-oriented search based on the psychological studies on human perception, and major emphasis on the saliently similar aspect of objects to be compared is placed and thus the search result is more agreeable for users. After relevant results are obtained, the cluster-based browsing algorithm is adopted for search result presentation based on social network analysis. By organizing the results in clustered lists, the user can have a general understanding of the whole collection by viewing only a small part of results and locate those of major interest rapidly. Experimental results demonstrate the advantages of the proposed algorithm over the traditional work.
文摘Among mobile users, ad-hoc social network (ASN) is becoming a popular platform to connect and share their interests anytime anywhere. Many researchers and computer scientists investigated ASN architecture, implementation, user experience, and different profile matching algorithms to provide better user experience in ad-hoc social network. We emphasize that strength of an ad-hoc social network depends on a good profile-matching algorithm that provides meaningful friend suggestions in proximity. Keeping browsing history is a good way to determine user’s interest, however, interests change with location. This paper presents a novel profile-matching algorithm for automatically building a user profile based on dynamic GPS (Global Positing System) location and browsing history of users. Building user profile based on GPS location of a user provides benefits to ASN users as this profile represents user’s dynamic interests that keep changing with location e.g. office, home, or some other location. Proposed profile-matching algorithm maintains multiple local profiles based on location of mobile device.
基金partially supported by the National Key Research and Development Program of China(2018YFB2100801)。
文摘The passwords for unlocking the mobile devices are relatively simple,easier to be stolen,which causes serious potential security problems.An important research direction of identity authentication is to establish user behavior models to authenticate users.In this paper,a mobile terminal APP browsing behavioral authentication system architecture which synthesizes multiple factors is designed.This architecture is suitable for users using the mobile terminal APP in the daily life.The architecture includes data acquisition,data processing,feature extraction,and sub model training.We can use this architecture for continuous authentication when the user uses APP at the mobile terminal.
文摘Jojoba is a desert shrub,introduced in the marginal areas of Kenya during 1980s.Jojoba domestication is being faced by browsing problems due to pastoralism in these areas.Massive browsing of leaves lowers photosynthesis leading to decline in plant functions.An experiment was set up in Maungu,with the aim of determining the effect of browsing on jojoba seedlings.The experimental design was a randomized complete block design with three treatments replicated three times.The treatments consisted of varying levels of browsing as follows:non browsed,50%browsed and fully browsed.Seedlings were raised for six months before sampling.Variables assessed were:survival,height,root-collar diameter,leaf size,root length and number,internode length,sprout number,root/shoot ratio and total biomass.ANOVA was performed to determine differences among the treatments whilst significant differences among the means were separated using least significant difference(LSD)at p≤0.05.Results showed fully browsed seedlings were significantly lower in height(26.2 cm),internode length(9.7 mm),leaf length(18.3 mm)and width(10.4 mm)and total fresh plant biomass(11.0 g)compared to the non browsed ones which showed 31.1 cm,23.2,36.1 and 16.6 mm and 17.8 g,respectively.On the other hand,fully browsed seedlings showed significantly higher root/shoot ratio.Seedling growth was negatively affected by severity of browsing which resulted in stunted growth.The study recommended that browsing of seedlings should be prevented since it hinders plant growth.
文摘Fire is regarded as management practice for maintaining grasslands and savannas. The vegetation occurring in fire prone areas becomes highly adapted to fire occurrences in savannas and grasslands. However, documentation on the influence of burning on vegetation is still limited in an albany thicket biome. The aim of the study was to evaluate the short-term influence of burning on species abundance, biomass production, wood plant density and browsing unit. Six plots (2500 m<sup>2</sup>) were demarcated;in each plot two parallel transects of 120 m<sup>2</sup> with 5 m distance apart were measured. Three plots were burned in spring season, while no burning was done on the other remaining plots. Forty points per plot were obtained using step-point method to determine the relative abundance at burned and unburned plots. Woody plants occurred within a transect were identified, counted and recorded to determine density and browsing unit. Three quadrats (<em>i.e</em>. 0.25 m<sup>2</sup>) per plot were randomly laid within the transect;aboveground plant material within a quadrat were harvested. A total of 18 samples were harvested and oven dried at 60<span style="white-space:nowrap;"><span style="white-space:nowrap;">˚</span></span>C for 48 hours to determine biomass production. The results showed that <em>Themeda triandra</em> (14%) and <em>Panicum maximum</em> (10%) were most abundant grass species at the burned plots. Burned plots had significantly higher biomass production (4804 kg/ha) compared to unburned plots (3641 kg/ha). <em>Vachellia karoo</em> (burned: 65.85% & unburn: 13.70%) and <em>Searsia pallens </em>(burned: 26.83% & unburned: 6.85%) were most dominant wood plant species at both burned and unburned plots. Burned plots had the highest browsing unit (3221 BU/ha) compared to unburned plots (2058 BU/ha). The decrease of woody plants at the burned plots proved that fire has a tremendous potential for managing woody plants. This study provided information on short-term influence of burning, however further long-term trials are required to determine the effects of burning.
