Can anyone identify this dragonfly from Eastern China?

The picture was taken close to Hangzhou (Eastern China).

05 June 2018 4,445 11 View

Can anyone provide samples of Nitella/Tolypella (Characeae) for phylogenetic analyses?

We are working on phylogeny of the European Characeae (green algea). We are still missing the following taxa: Nitella capillarisNitella flexilisTolypella intricata Can anyone provide the samples...

04 May 2017 2,038 0 View

Can anyone identify this skeleton part (marine/oceanic fish mouth)?

Probably marine fish mouth skeleton. Found on the Con Dao island (Vietnam).

03 April 2017 9,059 3 View

Can anyone identify these insects / Coleoptera from Costa Rica (Tapanti NP)?

The three Coleoptera species have been observed and photographed in April 2016 in Tapanti National Park (Costa Rica) - in mountainous forest with Oreomunnea and Alfaroa species (both Juglandaceae)...

09 October 2016 3,207 18 View

Can anyone identify these Crustacea/Decapoda from Iriomote Island (Southern Ryukyu, Japan)?

The crabs were observed and pictures were taken on oceanic shore and in mangroves of the Iriomote Island (Southern Ryukyu, Japan).

07 August 2015 316 7 View

Does anybody know any gymnosperm which is an obligate aquatic organism - other than Retrophlylum minus (Podocarpaceae) from New Caledonia?

In our recent global analysis of all extant gymnosperms we concluded that there is only one obligate "aquatic gymnosperm" taxon among ca. 1000 known species of this ancient plant group. Are there...

31 December 2014 3,314 3 View

Who knows this organism/phenomenon?

Found in Switzerland, close to a river on humid soil in December 2014. Fungal or algal organism?

31 December 2014 4,836 5 View

Why do some barks peel? What are the advantages of exfoliating for a tree?

01 January 1970 294 19 View

Is the dispersal unit of the relict tree genus Zelkova unusual/unique (twig fragment with dried leaves and fruits)?

01 January 1970 4,083 5 View

What are the countries most affected by extreme rainfall as a result of climate change?

Increased heat, drought and insect outbreaks, all associated to climate change, have increased wildfires. Decreasing water supplies, declined agricultural yields, health impacts in cities owing to...

01 March 2021 7,168 9 View

How to accurately quantify chitin?

Hi all, I have been working on the quantification of chitin in insect samples and feed for a while but I can notice that the quantification methods (e.g. exposure to HCl, NaOH, and weighing sample...

01 March 2021 1,843 2 View

Where to find data on trees in tropical agroforestry?

Hi, I'm looking for data (mainly related to management: growth rate, canopy size, soil and climate preferences, etc.) about tropical trees used in tropical agroforestry. Have you ever heard about...

28 February 2021 7,356 8 View

The Shannon's index is inversely proportional to Simpson's index (1-D)?

I'm having a problem with my bloxplot with Shannon's and Simpson's indexs. The value of Shannon for my Community 1 indicating higher diversity (in relation of the Community 2), but have lower...

26 February 2021 3,033 9 View

Your thoughts on the spherical densiometer to estimate relative species canopy cover?

Hi biologists and biogeomorphologists, I want to characterize vegetation plots on a transect that follows a successionnal gradient from a river bed to a mature forest. Ecologically, I am...

26 February 2021 5,720 2 View

Stress/strain tensors decomposition ???

25 February 2021 6,760 1 View

Bayesian decision trees and bayesian regression trees in Python and/or R?

I am looking for implementation of bayesian decision trees and bayesian regression trees in Python and/or R.. Do you know if the existing libraries support this

23 February 2021 6,689 3 View

Please help in identification of this insect?

This insect is minute in size around 1 mm and not clearly visible with naked eye.

22 February 2021 5,907 11 View

How to assure whether a regression tree overfit or not by seeing bias-variance value of the model?

Lets consider a regression tree in which variance is 1.1065*e-10 and bias is 2.962e-13. Also the model RMSE on training set is 1.5e-5 and on training set is 1.2950e-5. Is the model is overfit or...

22 February 2021 7,755 2 View

Is it possible, for a limited dateset of images, to use Convolution filters + Random Forest instead of UNet?

UNet is 'relatively' recent and was invented mainly to deal with biomedical images, yet is it also possible, for a limited dateset of images, to use Convolution filters + Random Forest instead of...

21 February 2021 4,858 3 View