Plant indicators of pH and water level in peatlands at Candle Lake, Saskatchewan

1971 ◽  
Vol 49 (9) ◽  
pp. 1661-1676 ◽  
Author(s):  
John K. Jeglum
Keyword(s):  
Water Level ◽  
Quantitative Data ◽  
Weighted Average ◽  
Similarity Coefficient ◽  
Standard Errors ◽  
Important Species ◽  
Environmental Correlates ◽  
Species Lists ◽  
Total Species ◽  
True Values

Quantitative data on vegetation, depth to water level, and pH of both moist peat and water from 113 stands of peatland near Candle Lake, Saskatchewan, are used to demonstrate relationships of peatland species to classes of pH and depth to water level, and to recognize plant indicators for the various classes. Weighted average and similarity coefficient techniques are used to estimate pH and depth to water level from total species lists and restricted lists of important species. Total species lists, combined with either weighted average or similarity coefficient techniques, yield indices with the highest correlations with the true values and the lowest standard errors of estimate. Depth to water level and pH are recognized as two important environmental correlates with floristic and vegetational variation in peatlands.

Species composition and distribution of marine macro algae at Co To and Thanh Lan archipelago

2020 ◽  
Vol 20 (3) ◽  
pp. 267-276
Author(s):  
Dam Duc Tien ◽  
Nguyen Thi Mai Anh ◽  
Linh Manh Nguyen ◽  
Pham Thu Hue ◽  
Lawrence Liao
Keyword(s):  
Species Composition ◽  
Littoral Zone ◽  
Marine Algae ◽  
Similarity Coefficient ◽  
Algal Flora ◽  
Average Value ◽  
Site Number ◽  
Species Composition And Distribution ◽  
Total Species ◽  
Macro Algae

This paper exhibites species composition and distribution of marine seaweed at 10 sites of Co To and Thanh Lan islands in May 2019. The studies record 76 species of marine algae in the area, belonging to four divisions: Cyanophytes, Rhodophytes, Ochrophytes and Chlorophytes. Among them, five species are classified into Cyanophytes (comprising 6.6% of total species); thirty-four species into Rhodophytes (44.7%); twenty-one species into Ochrophytes/Phaeophytes (27.6%) and sixteen species into Chlorophytes (21.1%). The species composition of marine seaweeds in Co To and Thanh Lan shows significant differences as follows: 22 species (sites number 4 and 10) to 58 species (site number 2) and the average value is 38.7 species per site. Sørensen similarity coefficient fluctuates from 0.33 (sites number 5 and 10) to 0.84 (sites number 1 and 3) and the average value is 0.53. The current investigations show that four species of twenty-one species are collected in the littoral zone and forty-two species in the sub-littoral zone (in which there are thirteen species distributed in both littoral zone and sub-littoral zone). The algal flora in Co To and Thanh Lan is characterized by subtropics.

scholarly journals Tropospheric moisture and its relation with rainfall due to nor’westers in Bangladesh

MAUSAM ◽  
2021 ◽  
Vol 58 (2) ◽  
pp. 153-160
Author(s):  
SAMARENDRA KARMAKAR ◽  
MD. MAHBUB ALAM
Keyword(s):  
Spatial Distribution ◽  
Water Content ◽  
Weighted Average ◽  
Precipitable Water ◽  
Specific Humidity ◽  
Standard Errors ◽  
Maximum Frequency ◽  
Maximum Rainfall ◽  
Average Water ◽  
Instability Indices

Attempts have been made to compute the precipitable water content of the troposphere, weighted average water vapour and to correlate these parameters with different instability indices and also with the next 24-hr rainfall, next 24-hr maximum rainfall and next 24-hr country averaged rainfall in order to predicting rainfall due to nor’westers in Bangladesh. It has been found that the maximum number of nor’westers occur when the precipitable water is 25-45 mm hr-1 between 1000 and 500 hPa, the maximum frequency being 48 in the range of 35-45 mm hr-1. The spatial distribution of precipitable water indicates that the maximum precipitable water is concentrated over the area near the places of nor’westers. The specific humidity has been found to increase on the dates of occurrence of nor’westers in Bangladesh on most occasions. Maximum number of nor’westers occurs when the weighted average specific humidity between the surface (1000 hPa) and 500 hPa is 8-12 g kg-1, the maximum frequency being 43 in the range of 8-10 g kg-1. The study reveals that nor’westers have been found to occur near or at the eastern end of maximum weighted average specific humidity. It has also been found that nor’westers occur near the point of inter-section of the axes of moist and dry zones. A number of parameters of the troposphere over Dhaka at 0000 UTC on the dates of occurrence of nor’westers such as precipitable water (mm/hr), MSWI, SWI, SWI/TT, (q1000 – q850) weighted averaged specific humidity have statistically significant correlations with next 24-hour rainfall at Dhaka, next 24-hour maximum rainfall in Bangladesh and country averaged rainfall. The correlation co-efficients are relatively small and the standard errors of estimates are higher. The small correlation co-efficients are significant because of the large number of data.

scholarly journals Structure and composition of the ground-herb community in a terra-firme Central Amazonian forest

2004 ◽  
Vol 34 (1) ◽  
pp. 53-59 ◽  
Author(s):  
Flávia Regina Capellotto Costa
Keyword(s):  
Community Structure ◽  
South America ◽  
Tropical Forests ◽  
Abundant Species ◽  
Evergreen Forest ◽  
Terra Firme ◽  
Important Species ◽  
Almost All ◽  
Total Species ◽  
Ground Herbs

The herb community of tropical forests is very little known, with few studies addressing its structure quantitatively. Even with this scarce body of information, it is clear that the ground herbs are a rich group, comprising 14 to 40% of the species found in total species counts in tropical forests. The present study had the objective of increasing the knowledge about the structure and composition of the ground-herb community and to compare the sites for which there are similar studies. The study was conducted in a tropical non-inundated and evergreen forest 90 km north of Manaus, AM. Ground herbs were surveyed in 22 transects of 40 m², distributed in five plots of 4 ha. The inventoried community was composed of 35 species, distributed in 24 genera and 18 families. Angiosperms were represented by 8 families and Pteridophytes by 10 families. Marantaceae (12 sp) and Cyperaceae (4 sp) were the richest families. Marantaceae and Poaceae were the families with greatest abundance and cover. Marantaceae, Poaceae, Heliconiaceae and Pteridophytes summed 96% of total herb cover, and therefore were responsible for almost all the cover of the community. The 10 most important species had 83.7% of the individuals. In general, the most abundant species were also the most frequent. Richness per transect varied from 7 to 19 species, and abundance varied from 30 to 114 individuals. The community structure was quite similar to 3 other sites in South America and one site in Asia.

Spatiotemporal variation among demersal ichthyofauna in a subtropical estuary bordering World Heritage-listed and marine protected areas: implications for resource management

2017 ◽  
Vol 68 (4) ◽  
pp. 703 ◽  
Author(s):  
Fernanda E. Possatto ◽  
Matt K. Broadhurst ◽  
Charles A. Gray ◽  
Henry L. Spach ◽  
Marcelo R. Lamour
Keyword(s):  
Marine Protected Areas ◽  
Fishing Effort ◽  
Spatiotemporal Variation ◽  
South American ◽  
Important Species ◽  
Prey Preferences ◽  
Subtropical Estuary ◽  
Species Specific ◽  
Total Species ◽  
Trawl Surveys

Benthic trawl surveys were performed to quantify the spatiotemporal distributions of teleosts and key abiotic associations throughout an ecologically important estuary within Brazil’s Atlantic Forest biosphere. Approximately 52000 fish (51% juveniles) representing 75 species were sampled, with residents accounting for 36 and 61% of total species and individuals respectively. Five artisanally important species comprised 77 and 81% of individuals and biomass respectively. Cathorops spixii was most abundant (>40% of total), whereas Stellifer rastrifer, Aspistor luniscutis, Sphoeroides greeleyi and S. testudineus collectively contributed towards 37 and 34% of individuals and biomass respectively. The abundance of A. luniscutis, C. spixii and S. rastrifer was negatively associated with salinity, whereas the presence of the latter two species was also positively associated with temperature, and S. greeleyi and S. testudineus (mostly adults) were more abundant in deeper areas. These relationships seemed to be affected by species-specific reproductive (S. rastrifer, C. spixii and A. luniscutis), habitat (S. greeleyi and S. testudineus) and prey preferences (juvenile C. spixii and A. luniscutis). Protection for these various species may be achieved via immediate fishing effort regulations, but more research is required to manage other anthropogenic effects. Such work should be a priority to ultimately preserve what is one of the most important South American biodiversity areas.

scholarly journals The Delta-Scoring Method of Tests With Binary Items: A Note on True Score Estimation and Equating

2017 ◽  
Vol 78 (5) ◽  
pp. 805-825 ◽  
Author(s):  
Dimiter M. Dimitrov
Keyword(s):  
Item Response Theory ◽  
Item Response ◽  
Large Scale ◽  
Standard Errors ◽  
True Score ◽  
Response Theory ◽  
Scoring Method ◽  
New Developments ◽  
Item Response Function ◽  
True Values

This article presents some new developments in the methodology of an approach to scoring and equating of tests with binary items, referred to as delta scoring (D-scoring), which is under piloting with large-scale assessments at the National Center for Assessment in Saudi Arabia. This presentation builds on a previous work on delta scoring and adds procedures for scaling and equating, item response function, and estimation of true values and standard errors of D scores. Also, unlike the previous work on this topic, where D-scoring involves estimates of item and person parameters in the framework of item response theory, the approach presented here does not require item response theory calibration.

The correction of observational data for instrumental band width

1955 ◽  
Vol 51 (3) ◽  
pp. 519-525 ◽  
Author(s):  
F. D. Kahn
Keyword(s):  
Observational Data ◽  
Band Width ◽  
Standard Errors ◽  
Interpolation Operator ◽  
Apparatus Function ◽  
Point Interpolation ◽  
Image Position ◽  
True Values ◽  
Class Of Functions

ABSTRACTThe readings Φ(x) of an instrument with the apparatus function g(x) are related to the true values f(x)of the observed function by the equationA three-point interpolation operator can be chosen to simulate the spreading action of a class of functions g(x). Under certain conditions the interpolation operator has an exact inverse which, when applied to Φ(x), gives a function which is a better approximation to f(x). The accuracy obtained is discussed, and the effect of the method on the standard errors in the measurement is found.

scholarly journals VIQoR: a web service for Visually supervised protein Inference and protein Quantification

2021 ◽  
Author(s):  
Vasileios Tsiamis ◽  
Veit Schwammle
Keyword(s):  
Quantitative Analysis ◽  
Web Service ◽  
Quantitative Data ◽  
Missing Values ◽  
Interactive Visualization ◽  
Weighted Average ◽  
Protein Quantification ◽  
Inference Problem ◽  
Protein Inference ◽  
Concentration Changes

Motivation: In quantitative bottom-up mass spectrometry (MS)-based proteomics the reliable estimation of protein concentration changes from peptide quantifications between different biological samples is essential. This estimation is not a single task but comprises the two processes of protein inference and protein abundance summarization. Furthermore, due to the high complexity of proteomics data and associated uncertainty about the performance of these processes, there is a demand for comprehensive visualization methods able to integrate protein with peptide quantitative data including their post-translational modifications. Hence, there is a lack of a suitable tool that provides post-identification quantitative analysis of proteins with simultaneous interactive visualization. Results: In this article, we present VIQoR, a user-friendly web service that accepts peptide quantitative data of both labeled and label-free experiments and accomplishes the processes for relative protein quantification, along with interactive visualization modules, including the novel VIQoR plot. We implemented two parsimonious algorithms to solve the protein inference problem, while protein summarization is facilitated by a well established factor analysis algorithm called fast-FARMS followed by a weighted average summarization function that minimizes the effect of missing values. In addition, summarization is optimized by the so-called Global Correlation Indicator (GCI). We test the tool on three publicly available ground truth datasets and demonstrate the ability of the protein inference algorithms to handle degenerate peptides. We furthermore show that GCI increases the accuracy of the quantitative analysis in data sets with replicated design. Availability and implementation: VIQoR is accessible at: http://computproteomics.bmb.sdu.dk:8192/app_direct/VIQoR/ . The source code is available at: https://bitbucket.org/vtsiamis/viqor/ .

scholarly journals SMALL BANDWIDTH ASYMPTOTICS FOR DENSITY-WEIGHTED AVERAGE DERIVATIVES

2013 ◽  
Vol 30 (1) ◽  
pp. 176-200 ◽  
Author(s):  
Matias D. Cattaneo ◽  
Richard K. Crump ◽  
Michael Jansson
Keyword(s):  
Weighted Average ◽  
Standard Errors ◽  
Monte Carlo Experiment ◽  
Finite Sample ◽  
Small Bandwidth ◽  
Nominal Coverage ◽  
Error Formulas ◽  
Coverage Rates ◽  
Asymptotic Validity ◽  
Average Derivative

This paper proposes (apparently) novel standard error formulas for the density-weighted average derivative estimator of Powell, Stock, and Stoker (Econometrica 57, 1989). Asymptotic validity of the standard errors developed in this paper does not require the use of higher-order kernels, and the standard errors are “robust” in the sense that they accommodate (but do not require) bandwidths that are smaller than those for which conventional standard errors are valid. Moreover, the results of a Monte Carlo experiment suggest that the finite sample coverage rates of confidence intervals constructed using the standard errors developed in this papercoincide (approximately) with the nominal coverage rates across a nontrivial range of bandwidths.

Field measurements of ice-jam-release surges

2005 ◽  
Vol 32 (4) ◽  
pp. 699-711 ◽  
Author(s):  
Spyros Beltaos ◽  
Brian C Burrell
Keyword(s):  
Water Level ◽  
Water Wave ◽  
Quantitative Data ◽  
Field Measurements ◽  
River Ice ◽  
Aquatic Life ◽  
Ice Jam ◽  
Ice Breakup ◽  
Induced Changes ◽  
Reporting Method

Surges are the most violent and spectacular events that occur during the ice breakup. Upon the release of an ice jam, water and ice held by the jam are suddenly free to move. The resulting surge generates increased water stages and higher flow velocities, such that the water wave and ice run pose a risk to downstream structures, people, and aquatic life. Climate-induced changes to river ice processes, such as enhanced mid-winter jamming or increased spring flows, could result in more frequent occurrence of major and damaging surges. To address a dearth of related quantitative data, a remote water-level reporting method has been developed and used to obtain field measurements on ice-jam generated surges. The results are consistent with the few available data but only partly conform to existing theories.Key words: breakup, celerity, ice jam, release, river, surge, wave.

scholarly journals Species diversity, taxon structure and distribution of the Chlorophytes on Truong Sa archipelago

2020 ◽  
Vol 20 (4) ◽  
pp. 427-436
Author(s):  
Dam Duc Tien ◽  
Nguyen Thi Thu Hang ◽  
Phan Thu Hue ◽  
Tran Dinh Lan
Keyword(s):  
Species Diversity ◽  
Intertidal Zone ◽  
Similarity Coefficient ◽  
Subtidal Zone ◽  
Number Of Species ◽  
Total Species

The results of research on characteristic of distribution and taxa structure of Chlorophytes (Chlorophyta) at nine islands of Truong Sa archipelago (Truong Sa, Da Tay, Thuyen Chai, Toc Tan, Sinh Ton, Nam Yet, Song Tu Tay, Da Nam and Son Ca) indicate that there are 67 species of Chlorophytes, they belong to 4 orders, 14 families and 22 genera. The number of species at the sampling islands ranged from 13 species/island (Toc Tan isd.) to 43 species/island (Nam Yet isd.) with the average of 25.5 species/island. Sorensen similarity coefficient at the sampling sections ranged from 0.24 (between Song Tu Tay and Thuyen Chai) to 0.74 (between Nam Yet and Song Tu Tay) with the average of 0.45. Among 67 species in nine islands, there are 10 species distributed only in the intertidal zone (they are occupying 14.9% of total species), 14 species (31.4%) in subtidal zone only and 43 species (64.2%) in both intertidal zone and subtidal zone. The number of species concentrates on some genera (Halimeda: 10 species; Caulerpa: 10 species; Codium: 6 species,...), they belong to Codiacea, Siphonales. There are some genera with only 1 species (Tydemania, Anadyomene, Microdictyon,...).

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