Bluesky Siphonophore Viewer

Posts now gather into a translucent siphonophore-like colony drifting through dark water. Oldest posts begin at one end of the spine and newer ones accumulate toward the other. Engagement thickens bells, membranes, and feeding clusters. Drag to orbit, mouse wheel to zoom, right-drag to pan, hover for a specimen overlay, click a segment to glide toward it, and double click the background to zoom to the whole organism.

atprotoalternatives.com/atprotoalternatives.com

A repository on Tangled

Nymph (biology)

In biology, a nymph is the juvenile form of some invertebrates, particularly insects, which undergoes gradual metamorphosis (hemimetabolism) before reaching its adult stage. Unlike a typical larva, a nymph's overall form already resembles that of the adult, except for a lack of wings and the emergence of genitalia. In addition, while a nymph moults, it never enters a pupal stage. Instead, the final moult results in an adult insect. Nymphs undergo multiple stages of development called instars.

beebz | Dec. 2nd, 2024

After a really annoying, stressful, and downright nauseating weekend, I feel like a wittled down eraser. Between being stalked and harrassed, losing a place I had loved, breaking in a new system member and seeing my friends suffer, this has felt like an extremely exhausting week.

Ecdysis

Ecdysis is the moulting of the cuticle in many invertebrates of the clade Ecdysozoa. Since the cuticle of these animals typically forms a largely inelastic exoskeleton, it is shed during growth and a new, larger covering is formed. The remnants of the old, empty exoskeleton are called exuviae.

charlebois.info/sveltekit-atproto-starter

A repository on Tangled

charlebois.info/sveltekit-atproto-starter

A repository on Tangled

Spatio-temporal simulations of bone remodelling using a bone cell population model based on cell availability

Here we developed a spatio-temporal bone remodeling model to simulate the action of Basic Multicelluar Units (BMUs). This model is based on two major extensions of a temporal-only bone cell population model (BCPM). First, the differentiation into mature resorbing osteoclasts and mature forming osteoblasts from their respective precursor cells was modelled as an intermittent process based on precursor cells availability. Second, the interaction between neighbouring BMUs was considered based on a ``metabolic cost'' argument which warrants that no new BMU will be activated in the neighbourhood of an existing BMU. With the proposed model we have simulated the phases of the remodelling process obtaining average periods similar to those found in the literature: resorption ($\sim22$ days) - reversal ($\sim$8 days) - formation ($\sim$ 65 days) - quiescence (560 - 600 days) and an average BMU activation frequency of $\sim$1.6 BMUs/year/mm$^3$. We further show here that the resorption and formation phases of the BMU become coordinated only by the presence of TGF-$\upbeta$ (transforming growth factor $\upbeta$, i.e. a major coupling factor stored in the bone matrix. TGF-$\upbeta$ is released through resorption so upregulating osteoclast apoptosis and accumulation of osteoblast precursors, i.e. facilitating the transition from the resorption to the formation phase at a given remodelling site. Finally, we demonstrate that this model can explain targeted bone remodelling as the BMUs are steered towards damaged bone areas in order to commence bone matrix repair.