The mechanisms of thermal solidification agent promoting steam diversion in heavy oil reservoirs

At high cycles of steam huff&puff,oil distribution in reservoirs becomes stronger heterogeneity due to steam channeling.Thermal solidification agent can be used to solve this problem.Its solution is a lowviscosity liquid at normal temperature,but it can be solidified above 80℃.The plugging degree is up to 99%at 250℃.The sweep efficiency reaches 59.2%,which is 7.3%higher than pure steam injection.In addition,simultaneous injection of viscosity reducer and/or nitrogen foams can further enhance oil recovery.The mechanism of this technology depends on its strong plugging ability,which changes the flowing pattern of steam to effectively mobilize remaining oil.Viscosity reducer and nitrogen foams further expand the sweep range and extends the effective period.Therefore,thermal solidification agent can plug steam channeling paths and adjust steam flowing direction to significantly enhance oil recovery at high cycles of steam huff&puff.

Fracture propagation law of temporary plugging and diversion fracturing in shale reservoirs under completion experiments of horizontal well with multi-cluster sand jetting perforation

This study conducted temporary plugging and diversion fracturing(TPDF)experiments using a true triaxial fracturing simulation system within a laboratory setting that replicated a lab-based horizontal well completion with multi-cluster sand jetting perforation.The effects of temporary plugging agent(TPA)particle size,TPA concentration,single-cluster perforation number and cluster number on plugging pressure,multi-fracture diversion pattern and distribution of TPAs were investigated.A combination of TPAs with small particle sizes within the fracture and large particle sizes within the segment is conducive to increasing the plugging pressure and promoting the diversion of multi-fractures.The addition of fibers can quickly achieve ultra-high pressure,but it may lead to longitudinal fractures extending along the wellbore.The temporary plugging peak pressure increases with an increase in the concentration of the TPA,reaching a peak at a certain concentration,and further increases do not significantly improve the temporary plugging peak pressure.The breaking pressure and temporary plugging peak pressure show a decreasing trend with an increase in single-cluster perforation number.A lower number of single-cluster perforations is beneficial for increasing the breaking pressure and temporary plugging peak pressure,and it has a more significant control on the propagation of multi-cluster fractures.A lower number of clusters is not conducive to increasing the total number and complexity of artificial fractures,while a higher number of clusters makes it difficult to achieve effective plugging.The TPAs within the fracture is mainly concentrated in the complex fracture areas,especially at the intersections of fractures.Meanwhile,the TPAs within the segment are primarily distributed near the perforation cluster apertures which initiated complex fractures.

Water hammer protection for diversion systems in front of pumps in long-distance water supply projects

For a water supply system with long-distance diversion pipelines, in addition to the water hammer problems that occur beyond pumps, the safety of the water diversion pipeline in front of pumps also deserves attention. In this study, a water hammer protection scheme combined with an overflow surge tank and a regulating valve was developed. A mathematical model of the overflow surge tank was developed, and an analytical formula for the height of the overflow surge tank was derived. Furthermore, a practical water supply project was used to evaluate the feasibility of the combined protection scheme and analyze the sensitivity of valve regulation rules. The results showed that the combined protection scheme effectively reduced the height of the surge tank, lessened the difficulties related to construction, and reduced the necessary financial investment for the project. The two-stage closing rule articulated as fast first and then slow could minimize the overflow volume of the surge tank when the power failure occurred, while the two-stage opening rule articulated as slow first and then fast could be more conducive to the safety of the water supply system when the pump started up.

Water diversion and agricultural production:Evidence from China

Water diversion can alleviate water shortages caused by the uneven distribution of water resources.China’s Southto-North Water Diversion Project(SNWD)is the largest water diversion project worldwide.Based on the prefecturelevel data of China’s Huang-Huai-Hai Plain from 2000 to 2020,this study employs an empirical strategy of Differencesin-Differences(DID)to analyze the impact of SNWD on agricultural production.The results show that SNWD has significantly increased agricultural production,measured by the agricultural value added.The estimated results of the benchmark model remain robust when the contemporaneous policy is addressed,an alternative outcome is used,subsamples are estimated,and alternative estimation techniques are employed.This study argues that the potential impact mechanism may be that SNWD significantly increases the acreage for cash crops but reduces that for grain crops.Heterogeneity analysis shows that in prefectures with high temperature or land potential,SNWD’s impact on agricultural value added is relatively low.In contrast,in areas with prolonged sunshine or high slopes,SNWD’s impact on agricultural value added is relatively large.Given the low added value of grain crops,the government should consider strengthening food security by subsidizing water supply to sustain grain production.

Resilience effects for household food expenditure and dietary diversity in rural western China

A more resilient livelihood is increasingly recognized as an efficient way to improve vulnerable households’food security and optimize their dietary decisions.This study quantifies rural household resilience in western China,identifies the three pillars(absorptive capacity,adaptive capacity,and transformative capacity)contribution to resilience,and then establishes the estimated Resilience Capacity Index(RCI)linked with food security and dietary diversity supported by the multiple indicator multiple cause(MIMIC)model.Results show that,despite geographical heterogeneity,the RCI consistently increased from 2015 to 2021.Households with a higher RCI inheriting better capacity to deal with risk and shocks are significantly and positively correlated with increasing food expenditure and diversifying food choices.It can be because resilient households will allocate more money to food expenditure instead of saving for livelihood uncertainty.Thus,policymakers can provide more incentives for rural households to adopt more dynamic and effective risk management strategies.This,in turn,could yield positive spillover effects by preventing human capital loss associated with dietary-related chronic diseases and mortality.

Off-farm employment,agriculture production activities,and household dietary diversity in environmentally and economically vulnerable areas of Asia

Access to off-farm employment has been expected to be a critical approach to ending hunger and all forms of malnutrition,two important targets of achieving Zero Hunger.This study aims to investigate the role of off-farm employment in improving dietary diversity through substitution effect and complementary effect with agricultural production activities and income effect.This study adopts Poisson/Tobit/Probit/OLS regressions and the instrument variable method based on the primary survey data collected among 1,282 households at 12 sites in environmentally and economically vulnerable areas of China,Nepal,Cambodia,Thailand,and Myanmar in 2019.The results show that off-farm employment is positively associated with household dietary diversity and the consumption of flesh meat,fish and other aquatic animals,fruits,and milk and dairy products,which are rich in protein and micronutrients.The results of mechanism analysis show that off-farm employment contributes to household dietary diversity by improving crop diversity,especially for poor households,boosting the probability of livestock raising for households with the middle one-third disposal income,and increasing household income.The positive association between off-farm employment and household dietary diversity is much higher for households with the bottom one-third disposal income,low illiteracy,and from upper-middle income countries.These findings imply that off-farm employment does play a vital role in achieving multiple benefits of poverty alleviation,malnutrition reduction,and agrobiodiversity conservation in environmentally and economically vulnerable areas.However,it may enlarge the gaps in dietary diversity between households with low human capital and from low and lower-middle income countries and those with high human capital and from middle-high countries.

Comparative assessment of mechanical and chemical fluid diversion techniques during hydraulic fracturing in horizontal wells

The application of fluid diversion during hydraulic fracturing is an evolving technology and has become popular amongst E&P operators over the past few years.The primary objective of the fluid diversion is to improve hydraulic fracturing treatment by increasing stimulated reservoir volume and improving hydrocarbon recovery.This is possible by achieving any of the following objectives:creating uniform distribution of treatment slurry within the target zone;treating unstimulated and under-stimulated zones;or by increasing fracture density by creating a complex fracture network.The fluid diversion application is also helpful in decreasing the number of stages(by increasing stage length)for multi-stage plug-n-perf(PnP)fracturing treatment.It is also applied to prevent fracture-driven interactions between adjacent wells,which is currently a major issue,especially in shale.In addition,for successful refracturing treatment,the diverter application is essential for isolating the existing fractures and redirecting the treatment slurry to the desired unstimulated zones.The diversion methods can be broadly categorized into the mechanical and chemical diversion.Several established mechanical diversion techniques are frac plugs,expandable casing patches,expandable liners,swellable packers,straddle packer assembly,sand plugs,frac sleeves,perforation ball sealers,and limited entry technique.The different chemical diversion techniques are particulates,fibers,gels,surfactants,perforation pods,and composite diverting.This paper describes the current status of established mechanical and chemical diverter technologies and examines their comparative advantages and challenges.Various techniques are suitable for diverter application,but the technique is selected based on the desired objective and conditions of the wellbore and reservoir.The general guidelines for selecting diversion techniques and operational considerations are also provided in the paper.The diagnosis of diversion treatment plays an essential role in diversion technique selection and optimization of selection parameters for the subsequent treatments.Therefore,the application of conventional surface pressure monitoring techniques and advanced diagnostic tools to evaluate diversion effectiveness are briefly described.Presently no standard laboratory testing method is established for the performance evaluation of diverting agents.Therefore,researchers have implemented various laboratory methods,which are briefly summarized in the paper.Significant insight into the diversion technology and guidelines for its selection and successful implementation is provided to help engineers to increase the effectiveness of hydraulic fracturing treatments.The limitations of individual diversion techniques are clarified,which provide the future scope of research for improvement in various diversion technologies.

Biodiversity metrics on ecological networks: Demonstrated with animal gastrointestinal microbiomes

Biodiversity has become a terminology familiar to virtually every citizen in modern societies.It is said that ecology studies the economy of nature,and economy studies the ecology of humans;then measuring biodiversity should be similar with measuring national wealth.Indeed,there have been many parallels between ecology and economics,actually beyond analogies.For example,arguably the second most widely used biodiversity metric,Simpson(1949)’s diversity index,is a function of familiar Gini-index in economics.One of the biggest challenges has been the high“diversity”of diversity indexes due to their excessive“speciation”-there are so many indexes,similar to each country’s sovereign currency-leaving confused diversity practitioners in dilemma.In 1973,Hill introduced the concept of“numbers equivalent”,which is based on Renyi entropy and originated in economics,but possibly due to his abstruse interpretation of the concept,his message was not widely received by ecologists until nearly four decades later.What Hill suggested was similar to link the US dollar to gold at the rate of$35 per ounce under the Bretton Woods system.The Hill numbers now are considered most appropriate biodiversity metrics system,unifying Shannon,Simpson and other diversity indexes.Here,we approach to another paradigmatic shift-measuring biodiversity on ecological networks-demonstrated with animal gastrointestinal microbiomes representing four major invertebrate classes and all six vertebrate classes.The network diversity can reveal the diversity of species interactions,which is a necessary step for understanding the spatial and temporal structures and dynamics of biodiversity across environmental gradients.

Contemporary outcomes of patients undergoing robotic-assisted radical cystectomy:A comparative analysis between intracorporeal ileal conduit and neobladder urinary diversions

Objective We aimed to compare perioperative and oncologic outcomes for patients undergoing robotic-assisted radical cystectomy(RARC)with intracorporeal ileal conduit(IC)and neobladder(NB)urinary diversion.Methods Patients undergoing RARC with intracorporeal urinary diversion between January 2017 and January 2022 at the Icahn School of Medicine at Mount Sinai,New York,NY,USA were indexed.Baseline demographics,clinical characteristics,perioperative,and oncologic outcomes were analyzed.Survival was estimated with Kaplan-Meier plots.Results Of 261 patients(206[78.9%]male),190(72.8%)received IC while 71(27.2%)received NB diversion.Median age was greater in the IC group(71[interquartile range,IQR 65-78]years vs.64[IQR 59-67]years,p<0.001)and BMI was 26.6(IQR 23.2-30.4)kg/m^(2).IC group was more likely to have prior abdominal or pelvic radiation(15.8%vs.2.8%,p=0.014).American Association of Anesthesiologists scores were comparable between groups.The IC group had a higher proportion of patients with pathological tumor stage 2(pT2)tumors(34[17.9%]vs.10[14.1%],p=0.008)and pathological node stages pN2-N3(28[14.7%]vs.3[4.2%],p<0.001).The IC group had less median operative time(272[IQR 246-306]min vs.341[IQR 303-378]min,p<0.001)and estimated blood loss(250[150-500]mL vs.325[200-575]mL,p=0.002).Thirty-and 90-day complication rates were 44.4%and 50.2%,respectively,and comparable between groups.Clavien-Dindo grades 3-5 complications occurred in 27(10.3%)and 34(13.0%)patients within 30 and 90 days,respectively,with comparable rates between groups.Median follow-up was 324(IQR 167-552)days,and comparable between groups.Kaplan-Meier estimate for overall survival at 24 months was 89%for the IC cohort and 93%for the NB cohort(hazard ratio 1.23,95%confidence interval 1.05-2.42,p=0.02).Kaplan-Meier estimate for recurrence-free survival at 24 months was 74%for IC and 87%for NB(hazard ratio 1.81,95%confidence interval 0.82-4.04,p=0.10).Conclusion Patients undergoing intracorporeal IC urinary diversion had higher postoperative cancer stage,increased nodal involvement,similar complications outcomes,decreased overall survival,and similar recurrence-free survival compared to patients undergoing RARC with intracorporeal NB urinary diversion.

Historical biogeography and evolutionary diversification of Lilium(Liliaceae): New insights from plastome phylogenomics

Here, we infer the historical biogeography and evolutionary diversification of the genus Lilium. For this purpose, we used the complete plastomes of 64 currently accepted species in the genus Lilium(14plastomes were newly sequenced) to recover the phylogenetic backbone of the genus and a timecalibrated phylogenetic framework to estimate biogeographical history scenarios and evolutionary diversification rates of Lilium. Our results suggest that ancient climatic changes and geological tectonic activities jointly shaped the distribution range and drove evolutionary radiation of Lilium, including the Middle Miocene Climate Optimum(MMCO), the late Miocene global cooling, as well as the successive uplift of the Qinghai-Tibet Plateau(QTP) and the strengthening of the monsoon climate in East Asia during the late Miocene and the Pliocene. This case study suggests that the unique geological and climatic events in the Neogene of East Asia, in particular the uplift of QTP and the enhancement of monsoonal climate, may have played an essential role in formation of uneven distribution of plant diversity in the Northern Hemisphere.

Effectiveness of groundwater extraction in Beijing since the ingauration of the first phase of the South-to-North Water Diversion Project, China

This study assess the effectiveness of groundwater pressure extraction in Beijing since the opening of the first phase of the South-to-North Water Diversion Project,using survey and evaluation methods.Firstly,an analysis of water consumption structure and the usage of diverted river water in Beijing in recent years was conducted.Secondly,the volume of groundwater pressure extraction in Beijing after the 33 project's inauguration was examined,revealing a decrease from 1.96 billion m^(3) in 2014 to 1.35 billion m^(3) in 2020.The proportion of water supply reduced from 52.3%in 2014 to 33.3%in 2020,leading to an optimized water supply structure.By the end of 2020,groundwater pressure extraction in Beijing is estimated at 446 million m3,with a substantial reduction in over-exploitation of groundwater.Groundwater resources have been effectively replenished,and the strategic reserve capacity has been enhanced.Furthermore,this study evaluates the change in groundwater levels as an indicator of the effectiveness of pressure extraction.The declining trend of groundwater levels in Beijing has been effectively mitigated,and there has been a consistent rebound in groundwater levels over the past five years.

Biodiversity responses to insular fragmentation in Amazonia: Two decades of research in the Balbina Hydroelectric Reservoir

As hydropower development expands across lowland tropical forests,flooding and concomitant insular fragmentation have become important threats to biodiversity.Newly created insular landscapes serve as natural laboratories to investigate biodiversity responses to fragmentation.One of these most iconic landscapes is the Balbina Hydroelectric Reservoir in Brazilian Amazonia,occupying>400000 ha and comprising>3500 forest islands.Here,we synthesise the current knowledge on responses of a wide range of biological groups to insular fragmentation at Balbina.Sampling has largely concentrated on a set of 22 islands and three mainland sites.In total,39 studies were conducted over nearly two decades,covering 17 vertebrate,invertebrate,and plant taxa.Although species responses varied according to taxonomic group,island area was consistently included and played a pivotal role in 66.7%of all studies examining patterns of species diversity.Species persistence was further affected by species traits,mostly related to species capacity to use/traverse the aquatic matrix or tolerate habitat degradation,as noted for species of vertebrates and orchid bees.Further research is needed to improve our understanding of such effects on wider ecosystem functioning.Environmental Impact Assessments must account for changes in both the remaining habitat amount and configuration,and subsequent long-term species losses.

Strong evidence for latitudinal diversity gradient in mosses across the world

Species richness generally decreases with increasing latitude,a biodiversity gradient that has long been considered as one of the few laws in ecology.This latitudinal diversity gradient has been observed in many major groups of organisms.In plants,the latitudinal diversity gradient has been observed in vascular plants,angiosperms,ferns,and liverworts.However,a conspicuous latitudinal diversity gradient in mosses at a global or continental scale has not been observed until now.Here,we analyze a comprehensive data set including moss species in each band of 20° in latitude worldwide.Our results show that moss species richness decreases strongly with increasing latitude,regardless of whether the globe is considered as a whole or different longitudinal segments(e.g.,Old World versus New World) are considered separately.This result holds when variation in area size among latitudinal bands is taken into account.Pearson's correlation coefficient between latitude and species richness is-0.99 for both the Northern and Southern Hemispheres.Because bryophytes are an extant lineage of early land plants and because mosses not only include most of extant species of bryophytes but also are important constituents of most terrestrial ecosystems,understanding geographic patterns of mosses is particularly important The finding of our study fills a critical knowledge gap.

Diversity of Orchids in Terms of Their Distribution, Uses and Conservation in Annapurna Conservation Area of Nepal

The Annapurna Conservation Area (ACA), the first conservation area and the largest protected area (PA) in Nepal, is incredibly rich in biodiversity. Notwithstanding this, orchids in the ACA have not been explored enough yet thus making the need for ambitious research to be carried out. Previous study only included 81 species of orchids within ACA. This study aims to update the record of species and genera richness in the ACA. In total 198 species of orchids, belonging to 67 genera (40% and 62% of the total recorded orchid species and genera in Nepal) has been recorded in ACA. This represents an increase of 144% in species and 56% in genera over the previous data. Out of the 198 species, 99 were epiphytes, 6 were holomycotrophic and 93 were terrestrial. Among the 67 genera, Bulbophyllum (17) species were dominant, followed by Dendrobium (16), Herminium (10), Coelogyne, Plantanthera (9 each), Eria, Habenaria, Oberonia (8 each), Calanthe (7), and Liparis (6). Fifty-six species were found to be ornamentally significant and 85 species medicinally significant.

Genetic Diversity of Jute Mallow (Corchorus spp.) Accessions Based on ISSR Markers

Jute mallow is a nutritious leafy vegetable. The leaves are rich in proteins, vitamins and essential amino acids. Molecular characterization of Jute mallow with focus on improvement of leaf yield is scarcely reported. In the present study, inter sequence simple repeats (ISSR) molecular markers were employed to assess genetic diversity and relationships of 83 accessions of Jute mallow from different parts of Africa and Asia conserved at the World Vegetable Center East and Southern Africa. A total of 89 bands were amplified by 8 ISSR primers. Number of polymorphic bands per primer ranged from 2 to 6 with an average of 2.75 bands per primer. Polymorphic information content (PIC) values ranged from 0.390 to 0.760 with average of 0.53. Average Nei’s gene diversity (h) and Shannon’s information index (I) were 0.335 and 0.494 respectively. The highest pairwise genetic distance was 0.431 observed in a population from East Africa accessions. PC1 and PC2 axis explained 21.69% and 11.66% of the total variation respectively. UPGMA cluster analysis grouped the accessions into six main clusters at genetic similarity coefficient of 0.53 as standard value for classification. These results have important implications for jute mallow breeding and conservation.

Genetic Diversity in Cowpea (Vigna unguiculata (L.) Walp) under Two Growing Conditions*

This study explores the use of genetic variability for advancing the genetic improvement of Cowpea (Vigna unguiculata (L.) Walp), particularly in response to insect infestation stress. Over a period spanning 2015 to 2017, forty accessions of cowpeas were evaluated to determine their variability under both insecticide spray and no insecticide spray conditions at the Teachings and Research Farms, Federal University of Agriculture, Abeokuta. The experimental design was a randomized complete block design in three replicates. The accessions were evaluated for plant height, leaf length, leaf width, number of days of 50% flowering, number of pods per plant, pod length, number of seeds per plant, 100-seed weight, and seed yield. Data collected were subjected to principal component and single linkage cluster analyses. Principal axis I (PCA1) accounted for 39% and 35% under insecticide spray and no insecticide spray respectively to the total variation in the accessions. Plant height with a factor score of 0.38, leaf length (0.41), number of leaves (0.37), and 100-seed, weight (0.30) was related to PCAI under insecticide spray while leaf width (0.32). Pod length (0.37) and number of seeds/plant (0.38) were significant to PCA1 under no insecticide spray. Notably, accessions such as SAMPEA6, SAMPEA10, IFE-Brown, and IFE-BPE exhibited consistent performance across both conditions, while others displayed condition-specific attributes. For instance, NGB1063, NGB1152, and NGB1093 demonstrated distinct traits under insecticide spray, while NGB1146 and NGB1124 exhibited notable characteristics under no insecticide spray conditions. Therefore, identifying these forty accessions with desirable traits hold promise for future genetic improvement efforts of cowpea cultivation in Nigeria and beyond.

Dietary Diversity and Food Security Status among Cameroonian Adults Living in Semi-Urban Areas: A Cross-Sectional Study

Introduction: Food security is one of the greatest challenges that most African countries face. It is a concept that considers not only food quantity but also food quality. The objective of this study was to describe dietary diversity and food security status at the individual level in Cameroonian populations. Methods: A total of 1180 men and women aged 20 and over and living in the West, North West, and Littoral regions of Cameroon were recruited. Data on dietary habits were collected through the frequency of consumption of various food groups. Dietary diversity was assessed using a 24-hour dietary recall. Food security status was determined by combining two indicators (food consumption score and individual food diversity score). Results: The mean dietary diversity score of the population was 3.53 ± 1.44, p Conclusion: The diet diversity of adults living in the West, North West, and Littoral regions of Cameroon is medium. Although half of the study population was food secure, there is a need to implement food security policies further to reduce food insecurity among the Cameroonian population.

Floristic Diversity, Stand Structure and Plant Life Traits in the Forest-Savanna Mosaic at Ndjole (Centre Cameroon)

With the aim of assessing floristic diversity, stand structure and vegetation ecology, the present work was carried out in the savanna mosaic forest of the locality of Ndjole (Centre Cameroon). A total of 30 floristic plots of 40 m × 40 m (1600 m2) were delineated in the different ecosystems (forest, forest-savanna contact zone and the savanna). Within each plot, all individuals with a diameter at breast height ≥ 10 cm at 1.30 m were taken into account. ANOVA was used to compare the means of the diversity indices of the different ecosystems, and the DUNCAN test at 5% significance level (XLSTAT 2016) to separate these means. A total of 85 species belonging to 67 genera and 33 families were recorded. That is, 68 species in semi-caducifolia forest, 45 in forest-savanna contact zone and 18 in savanna. Urticaceae, Combretaceae, Apocynaceae, Myristicaceae and Euphorbiaceae are the most diverse families in the forest. On the other hand, in contact zones, the Euphorbiaceae, Fabaceae, Annonaceae and Moraceae families are the most diversified, while in the savannas, the Combretaceae, Fabaceae and Annonaceae families are the most diversified. Shannon’s diversity index values (1.7 to 2.37 bits) reflect low specific diversity;Piélou’s equitability (0.86 to 0.9) shows good distribution of individuals within species. The diametric structure of woody species shows an inverted “J” shape in all plant communities. This indicates a high regeneration potential characterized by a greater number of small trees than large trees. Mesophanerophytes and megaphanerophytes are dominant in forests and forest-savanna contact zones, and microphanerophytes in the savannas. Endozoochory is the main mode of diaspore dissemination. As regards the distribution of phytogeographical types, it shows the overall dominance of Guineo-Congolese species in all plant communities. Our study provides detailed data on forest-savanna floristic and plant life traits in the mosaic and recommends further studies on the impact of environmental parameter variations on the forest encroachment into savanna.

Improving Diversity with Multi-Loss Adversarial Training in Personalized News Recommendation

Users’interests are often diverse and multi-grained,with their underlying intents even more so.Effectively captur-ing users’interests and uncovering the relationships between diverse interests are key to news recommendation.Meanwhile,diversity is an important metric for evaluating news recommendation algorithms,as users tend to reject excessive homogeneous information in their recommendation lists.However,recommendation models themselves lack diversity awareness,making it challenging to achieve a good balance between the accuracy and diversity of news recommendations.In this paper,we propose a news recommendation algorithm that achieves good performance in both accuracy and diversity.Unlike most existing works that solely optimize accuracy or employ more features to meet diversity,the proposed algorithm leverages the diversity-aware capability of the model.First,we introduce an augmented user model to fully capture user intent and the behavioral guidance they might undergo as a result.Specifically,we focus on the relationship between the original clicked news and the augmented clicked news.Moreover,we propose an effective adversarial training method for diversity(AT4D),which is a pluggable component that can enhance both the accuracy and diversity of news recommendation results.Extensive experiments on real-world datasets confirm the efficacy of the proposed algorithm in improving both the accuracy and diversity of news recommendations.

Differential roles of seed and sprout regeneration in forest diversity and productivity after disturbance

Natural regeneration after disturbances is a key phase of forest development,which determines the trajectory of successional changes in tree species composition and diversity.Regenerating trees can originate from either seeds or sprouts produced by disturbed trees with sprouting ability.Although both regeneration strategies often develop and co-occur after a disturbance,they tend to affect forest development differently due to significant functional differences.However,the origin of tree regeneration is rarely distinguished in post-disturbance forest surveys and ecological studies,and the differential roles of seed and sprout regeneration in forest productivity and diversity remain poorly understood.To address these research gaps,we explored the role of sprout and seed regeneration in the formation of woody species diversity and above-ground biomass(AGB)productivity in early-stage forest development.Data were collected in two experimental forest stands in the Czech Republic,where trees were cut with varying intensities with the density of residual(uncut)trees ranging from 0 to 275 trees per hectare.All trees were mapped and their sizes were measured before cutting and then,either as a stump with sprouts or a residual tree,remeasured 11 years later.In addition,all tree saplings were mapped and measured 11 years after logging,and their origin(sprout or seed)was identified.To assess abundances and productivity,we estimated AGB of all2,685 sprouting stumps of 19 woody species and 504 generative(i.e.,seed origin)individuals of 16 woody species,using allometric equations.Mixed-effects models were used to analyze the effects of each regeneration strategy on woody species diversity and the total AGB under varying densities of residual trees.Nonmetric multidimensional scaling was used to evaluate the effect of regeneration strategies on species composition.AGB and diversity of sprouts were significantly higher than those of seed regeneration.Sprouts formed on average97.1%of the total regeneration AGB in H ady and 98.6%in Sobe s ice.The average species richness of sprouts was4.7 in H ady and 2.2 in Sob e sice,while the species richness of seed regeneration averaged 2.1 and 1.1 in H ady and Sob e sice,respectively.Increasing density of residual trees reduced AGB and diversity of both sprouts and seed regeneration,but seed regeneration was affected to a greater extent.Residual trees had an especially strong inhibitory effect on the establishment of seed regeneration.Consequently,seed-originated saplings were nearly absent in plots with high residual tree density,and abundant sprouts accounted for most of the AGB and diversity.However,unlike sprouts whose species composition resembled that of the original stand,seed regeneration brought in new species,enriching the stand?s overall species pool and beta diversity.Our results demonstrated differential roles of sprout and seed regeneration in the early stage of forest succession.Sprout regeneration was the main source of woody AGB productivity as well as species diversity,and its importance increased with the increasing density of standing mature trees.The results indicate the crucial yet previously underestimated role of sprout regeneration in post-disturbance forest dynamics.They suggest that the presence of residual mature trees,whether retained after partial cutting or undisturbed,can substantially suppress seed regeneration while the role of sprout regeneration in early succession becomes more distinctly evident.