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Expected adult lifespan in tropical trees: Long-term matrix demography in a large plot

Forest Ecosystems 2022年第4期9卷 558-566页

作者： richard condit Morton Arboretum 4100 Illinois Rte.53LisleIL60532USA Institute for Marine Sciences University of CaliforniaSanta CruzUSA

Background: Documenting the entire lifetime of long-lived organisms requires splicing together short-term observations. Matrix demography provides a tool to calculate lifetime statistics, but large samples from juvenile to adult are needed, and few such studies have been done in tropical trees because high species diversity limits sample sizes. The 50-ha plot at Barro Colorado in Panama was designed to provide large samples, and with 30years of censuses, accurate population matrices can be ***: In 31 abundant species, I divided all individuals≥1 cm dbh into 4 or 5 size class in each of seven censuses. Movements of stems between size classes over two censuses are termed transitions, and I constructed complete transition matrices for each species. From the matrices, I derived analytic solutions for lifetime demographic statistics. Expected adult lifespan from the sapling stage was the key ***: Expected adult lifespan from the sapling stage varied 100-fold over the 31 species, from 0.5 to 50 years,and maturation time varied from 19 to nearly 200 years. Species with the highest growth rates also had high death rates, and theoretical calculations of reproductive lifespan show that the fast-growing pioneer species have short expected adult lifespans relative to the average slow-growing, shade-tolerant species. Within the slowgrowth category, however, there was high variation in expected adult lifespan, and several shade-tolerant species under-performed the pioneers in terms of adult ***: Analytical solutions from population matrices allow theoretical analyses that integrate short-term growth records into lifespans of tropical trees. The analyses suggest that pioneer species must reproduce more successfully than shade-tolerant species to persist in the Barro Colorado forest. My next goal is to incorporate seed production and germination into lifetime matrix demography to test this hypothesis.

关键词： Tree lifespan Tropical tree Matrix demography

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Distribution of Panama’s narrow-range trees:are there hot-spots?

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Forest Ecosystems 2021年第4期8卷 801-809页

作者： Elizabeth Tokarz richard condit Morton Arboretum 4100 Illinois Rte.53LisleIL 60532USA

Background:Tree species with narrow ranges are a conservation concern because heightened extinction risk accompanies their small *** risks for these species is challenging,however,especially in tropical flora where their sparse populations seldom appear in traditional plots and ***,we utilize instead large scale databases that combine tree records from many sources to test whether the narrow-range tree species of Panama are concentrated at certain elevations or in certain *** investigations have suggested that the Choco region of eastern Panama and the high mountains of western Panama may be potential hotspots of narrow-range tree ***:All individual records were collected from public databases,and the range size of each tree species found in Panama was estimated as a polygon enclosing all its *** with ranges<20,000 km^(2) were defined as narrow *** divided Panama into geographic regions and elevation zones and counted the number of individual records and the species richness in each,separating narrow-range species from all other ***:The proportion of narrow endemics peaked at elevations above 2000 m,reaching 17.2% of the species *** elevation<1500 m across the country,the proportion was 6-11%,except in the dry Pacific region,where it was 1.5%.Wet forests of the Caribbean coast had 8.4% narrow-range species,slightly higher than other *** total number of narrow endemics,however,peaked at mid-elevation,not high elevation,because total species richness was highest at ***:High elevation forests of west Panama had higher proportions of narrow endemic trees than low-elevation regions,supporting their hot-spot status,while dry lowland forests had the lowest *** supports the notion that montane forests of Central America should be a conservation ***,given generally higher diversity at low-to mid-elevation,lowlands are also import

关键词： Narrow endemic trees Biodiversity hot-spots Panama Rarefaction High elevations BIEN database Narrow-range

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Trees of Panama: A complete checklist with every geographic range

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Forest Ecosystems 2020年第3期7卷 526-538页

作者： richard condit Salomón Aguilar Rolando Pérez Morton Arboretum 4100 Illinois Rte.53Lisle60532ILUSA Smithsonian Tropical Research Institute Panama CityPanama

Background Central America is one of the most diverse floristic provinces in the world,but comprehensive plant lists for the region are incomplete and need frequent *** geographic ranges of individual species are seldom *** detailed forest inventory plots of Panama thus lack a global geographic *** order to provide one,we assembled a thoroughly vetted checklist of all tree species of Panama,along with an estimate of each one’s range size based on published specimen *** 1)Panama has 3043 tree species in 141 families and 752 genera;57.6%were≥10 m tall and 16.9%were 3-5 m tall.2)The widest ranges were>1.5×107 km2,covering the entire neotropics and reaching>30∘latitude;12.4%of the species had ranges exceeding 107 *** median range was 6.9×105 km2.3)At the other extreme,16.2%of the species had a range<20,000 km2,a criterion suggesting endangered status.4)Range size increased with a tree species’height and varied significantly among families.5)Tree census plots,where we mapped and measured all individuals,captured 27.5%of the tree species,but a biased selection relative to range size;only 4.5%of the species in plots had ranges<20,000 *** Our checklist of the trees of Panama,based on rigorous criteria aimed at matching plot censuses,is 20%larger than *** recording species’maximum heights,we allow comparisons with other regions based on matching definitions,and the range sizes provide a quantitative basis for assessing extinction *** next goal is to merge population density from plot censuses to add rigor to predictions of extinction risk of poorly-studied tropical tree species.

关键词： red Trees of Panama A complete checklist with every geographic range

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Demographic trends and climate over 35 years in the Barro Colorado 50 ha plot

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Forest Ecosystems 2017年第4期4卷 273-285页

作者： richard condit Rolando Pérez Suzanne Lao Salomón Aguilar Stephen P. Hubbell Field Museum of Natural History 1400 S

Background： The first three censuses of the 50-ha plot at Barro Colorado Island spanned an unusually harsh dry season during the 1983 El Nitro. By the early 1990s, we had documented increases in tree mortality, tree growth, and large population fluctuations of many species during the 1982-1985 census interval. At the time, we asserted that increasing drought frequency would greatly affect the forest. With the benefit of five more censuses at Barro Colorado from 1995-2015, we can now put the 1980 conditions in a longer perspective and test the hypothesis that increasing droughtiness has continued to change the forest. Methods： A 50-ha forest plot on Barro Colorado Island was censused eight times, in 1982 and every five years since 1985. All free-standing woody stems were measured, mapped, and identified in each census. Results： 1） The period 1982-1992 included several extreme dry seasons, not just 1983, but since then there have been few such droughts. 2） Dbh growth declined from a peak in the early 1980s to its lowest in the early 1990s. From 1995-2015 it increased slightly, but not returning to the initial peak. Nearly every species and all dbh categories followed the same pattern. 3） The elevated stand-wide mortality rate of large trees during the 1982-1985 drought has not returned, and most individual species showed the same pattern of elevated mortality in the 1980s followed by low and fairly stable mortality after 1990. 4） Sapling mortality declined after 198,5, but rose again in the late-90s, so the 1980s drought period no longer looks unusual. Mortality of individual species＇ saplings fluctuated erratically, including cases where mortality during the drought was lower than after. 5） Population sizes of individual species fluctuated in all possible directions. Some species declined precipitously during the drought, then recovered, but others did not recover. Other species increased in abundance during the drought. Conclusions＂ Droughts of the 1980s elevated tr

关键词： Demographic trends climate

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Spatial and temporal analysis of beta diversity in the Barro Colorado Island forest dynamics plot, Panama

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Forest Ecosystems 2019年第1期6卷 76-86页

作者： Pierre Legendre richard condit Département de sciences biologiques Université de Montréal Field Museum of Natural History Morton Arboretum

Background: Ecologists are interested in assessing the spatial and temporal variation in ecological surveys repeated over time. This paper compares the 1985 and 2015 surveys of the Barro Colorado Forest Dynamics plot(BCI), Panama,divided into 1250(20 m × 20 m) ***, spatial analysis: Total beta diversity was measured as the total variance of the Hellinger-transformed community data throughout the BCI plot. Total beta was partitioned into contributions of individual sites(LCBD indices), which were tested for significance and ***, spatial analysis: LCBD indices indicated the sites with exceptional community composition. In 1985,they were mostly found in the swamp habitat. In the 2015 survey, none of the swamp quadrats had significant *** happened to the tree community in the interval?Methods, temporal analysis: The dissimilarity in community composition in each quadrat was measured between time 1(1985) and time 2(2015). Temporal Beta Indices(TBI) were computed from abundance and presence-absence data and tested for significance. TBI indices can be decomposed into B = species(or abundances-per-species) losses and C = species(or abundances-per-species) gains. B-C plots were produced; they display visually the relative importance of the loss and gain components, through time, across the ***, temporal analysis: In BCI, quadrats with significant TBI indices were found in the swamp area, which is shrinking in importance due to changes to the local climate. A published habitat classification divided the BCI forest plot into six habitat zones. Graphs of the B and C components were produced for each habitat group. Group 4(the swamp) was dominated by species(and abundances-per-species) gains whereas the five other habitat groups were dominated by losses, some groups more than ***: We identified the species that had changed the most in abundances in the swamp between T1 and *** analysis supported the hypothesis that the

关键词： Beta diversity B-C plots BCI forest dynamics plot Space-time analysis Temporal beta diversity

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Demographic variation and habitat specialization of tree species in a diverse tropical forest of Cameroon

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Forest Ecosystems 2014年第4期1卷 201-213页

作者： David Kenfack George B Chuyong richard condit Sabrina E Russo Duncan W Thomas Center for Tropical Forest Science - Forest GEO Botany Department Smithsonian Tropical Research Institute Department of Botany and Plant Physiology University of Buea Center for Tropical Forest Science Smithsonian Tropical Research Institute School of Biological Sciences University of Nebraska Department of Biological Sciences Washington State University

Background： Many tree species in tropical forests have distributions tracking local ridge-slope-valley topography. Previous work in a 50-ha plot in Korup National Park, Cameroon, demonstrated that 272 species, or 63% of those tested, were significantly associated with topography. Methods： We used two censuses of 329,000 trees ≥1 cm dbh to examine demographic variation at this site that would account for those observed habitat preferences. We tested two predictions. First, within a given topographic habitat, species specializing on that habitat （＇residents＇） should outperform species that are specialists of other habitats （＇foreigners＇）. Second, across different topographic habitats, species should perform best in the habitat on which they specialize （＇home＇） compared to other habitats （＇away＇）. Species＇ performance was estimated using growth and mortality rates. Results： In hierarchical models with species identity as a random effect, we found no evidence of a demographic advantage to resident species. Indeed, growth rates were most often higher for foreign species. Similarly, comparisons of species on their home vs. away habitats revealed no sign of a performance advantage on the home habitat. Conclusions＂ We reject the hypothesis that species distributions along a ridge-valley catena at Korup are caused by species differences in trees _〉1 cm dbh. Since there must be a demographic cause for habitat specialization, we offer three alternatives. First, the demographic advantage specialists have at home occurs at the reproductive or seedling stage, in sizes smaller than we census in the forest plot. Second, species may have higher performance on their preferred habitat when density is low, but when population builds up, there are negative density-dependent feedbacks that reduce performance. Third, demographic filtering may be produced by extreme environmental conditions that we did not observe during the census interval.

关键词： tree Demographic variation and habitat specialization of tree species in a diverse tropical forest of Cameroon Figure

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Bound and Resonating Multiquark Configurations

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Chinese Physics Letters 2024年第8期41卷 8-12页

作者： Jean-Marc richard Institut de Physique des 2 Infinis de Lyon Université Claude Bernard(Lyon 1) CNRS-IN2P34 rue Enrico Fermi69622 VilleurbanneFrance

We review the predictions of quark models for multiquark configurations that are bound or resonant states,and compare different methods for estimating the properties of resonances.

关键词： quark Configuration resonant

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RecBERT:Semantic recommendation engine with large language model enhanced query segmentation for k-nearest neighbors ranking retrieval

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Intelligent and Converged Networks 2024年第1期5卷 42-52页

作者： richard Wu the Dublin Unified School District and the SF Artificial Intelligence Club DublinCA 94568USA

The increasing amount of user traffic on Internet discussion forums has led to a huge amount of unstructured natural language data in the form of user *** modern recommendation systems rely on manual tagging,relying on administrators to label the features of a class,or story,which a user comment corresponds *** common approach is to use pre-trained word embeddings to compare class descriptions for textual similarity,then use a distance metric such as cosine similarity or Euclidean distance to find top k ***,neither approach is able to fully utilize this user-generated unstructured natural language data,reducing the scope of these recommendation *** paper studies the application of domain adaptation on a transformer for the set of user comments to be indexed,and the use of simple contrastive learning for the sentence transformer fine-tuning process to generate meaningful semantic embeddings for the various user comments that apply to each *** order to match a query containing content from multiple user comments belonging to the same class,the construction of a subquery channel for computing class-level similarity is *** channel uses query segmentation of the aggregate query into subqueries,performing k-nearest neighbors(KNN)search on each individual *** achieves state-of-the-art performance,outperforming other state-of-the-art models in accuracy,precision,recall,and F1 score for classifying comments between four and eight classes,*** outperforms the most precise state-of-the-art model(distilRoBERTa)in precision by 6.97%for matching comments between eight classes.

关键词： sentence transformer simple contrastive learning large language models query segmentation k-nearest neighbors

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Near-infrared Emissive 1,2-Dioxetane-based Chemiluminescent Probes

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Chemical Research in Chinese Universities 2024年第5期40卷 806-823页

作者： CHEN Yingqi BUDIANTA richard NING Yingying Spin-X Institute School of Chemistry and Chemical EngineeringSchool of Biomedical Sciences and EngineeringState Key Laboratory of Luminescent Materials and DevicesGuangdong-Hong Kong-Macao Joint Laboratory of Optoelectronic and Magnetic Functional MaterialsSouth China University of TechnologyGuangzhou510641P.R.China

Chemiluminescence,a phenomenon emitting light from chemical reactions rather than photon absorption,has gained significant interest for applications in bioimaging and biosensing due to its high sensitivity and low background *** there is a growing interest in near-infrared(NIR)chemiluminescent probes for improved tissue penetration and reduced *** review summarizes NIR emissive chemiluminescent probes based on 1,2-dioxetane and discusses their chemical structures and *** modification strategies for red-shifting wavelength and enhancing brightness include incorporating electron-withdrawing groups,designing chemiluminophore-fluorophore cassettes,and exploring alternative chemiluminescent *** review aims to inspire the exploration of NIR chemiluminescent probes in disease detection and treatment.

关键词： Chemiluminescence Near-infrared Dioxetane Bioimaging Biosensing

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Parameter-Free Shifted Laplacian Reconstruction for Multiple Kernel Clustering

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IEEE/CAA Journal of Automatica Sinica 2024年第4期11卷 1072-1074页

作者： Xi Wu Zhenwen Ren F.richard Yu the School of National Defence Science and Technology Southwest University of Science and TechnologyMianyang 621010China the School of National Defence Science and Technology Southwest University of Science and TechnologyMianyang 621010 the Guangxi Key Laboratory of Machine Vision and Intelligent Control Wuzhou UniversityWuzhou 543002 the Guangdong Laboratory of Artificial Intelligence and Digital Economy(SZ) Shenzhen 518060China

Dear Editor,This letter proposes a parameter-free multiple kernel clustering(MKC)method by using shifted Laplacian *** MKC can effectively cluster nonlinear data,but it faces two main challenges:1)As an unsupervised method,it is up against parameter problems which makes the parameters intractable to tune and is unfeasible in real-life applications;2)Only considers the clustering information,but ignores the interference of noise within Laplacian.

关键词： parameter letter Parameter

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