Trees and plants gather nutrients from the soil through absorption into their roots. But there are those unfortunate plants that live in such desolate conditions that there are very little nutrients to absorb. Any that do get caught need to be held onto and used as efficiently as possible. This is where the action of resorption comes from. When a leaf starts senescing (just the technical term for ageing) the plant can pull back and retranslocate the nutrients from the failing leaf in order that they don’t get lost when the leaf inevitably falls off. The global average is to be able to pull back and recycle a bit over 60% of the nitrogen (N) and phosphorus (P) in each leaf. All plants do this to some degree but it was theorised that in nutrient scarce environments the plants will rely on the process a lot more. Interestingly, one study showed an increased resorption in desert shrubs than nondesert shrubs, while another has shown that there is no difference.
My ability to use computer programs is incredibly limited. I can often make them do roughly what I want (and always what I tell them) but the most infuriating part for me was when I’d (thought I’d) copied a piece of code perfectly from a different program, but it wasn’t working in its new context. I think this is no doubt a universal feeling, failed imitation leads to frustration. Now for the brain. Everyone knows that the brain can be described as a computer, running algorithms and producing thoughts. But this a purely external view, it doesn’t take into account what the brain is actually like. The other main model of the brain is the neural network. This matches the physical structure of the brain, a series many units which work together in a highly dynamic pattern. But no neural network we’ve ever been able to model has been able to produce any higher level cognitive function.
As a child I, like many children, was a very big fan of dinosaurs. I would like to think that my obsession was perhaps a bit more technical than the average and so I can distinctly remember memorising (or at least attempting to) large phylogenies (those trees of species) often extending long before and long after the reign of the dinosaurs. Today’s paper is about the relation between species, although it isn’t giant lizards, but bony fish, which are the target of the study.
There are many aspects of humans that makes our species unique among animals. Our intelligence is clear but from that stems our language and empathy. We also have acute mechanical abilities, our standing upright and our incredible stamina are also unique aspects of being human. But most of all, of course, is our opposable thumbs. They grant us the ability to perform such delicate manipulation that so many tasks, such as the typing I’m doing right now, become simple when really it’s a whole more complicated than we ever really think about. It is unsurprising, therefore, that people who have suffered spinal cord damage report that restoration of arm and hand functions is what they desire most. Important for spinal damage, and even more so for amputation, the brain-computer interface so that the control of a robotic replacement can be optimised is essential.
Ultrasound refers to any sound which is of higher frequency than the human ear can hear. I don’t feel confident in this statement but I think most people will have heard of ultrasound with respect to its scanning potential of foetuses. A very useful application as you certainly wouldn’t want to use X-rays to determine the health of the baby lest that health be very short. Ultrasound also has many more applications beyond just sensing as being able to deliver mechanical energy to specific parts of the body is incredible useful. I have covered one of these used before in this post which describes a study on the effects of ultrasound targeted at the blood brain barrier. Today’s work is on a very similar subject.
In eukaryotic cells (basically those that aren’t bacterial) there exists a structure called the endoplasmic reticulum. A reticulum is any large mesh, but in this case, the mesh is a membrane made of flattened tubes called cisternae that pervades the cell and assists in multiple functions. In particular it works on the synthesis, folding and transport of proteins and can be found in pretty much all animal cells except red blood cells and spermatozoa. There are two distinct structures which the endoplasmic reticulum takes: the one that surrounds the nucleus is flatter, more like a sheet and the one that spreads throughout the cell thickens into the clear tube network. But this structure isn’t set, it’s actually highly dynamic and will restructure itself over time forming entirely new branches of spreading tubes.
It’s interesting to think back to primary school science and what we were taught. My family were astounded (as well as quite stubborn) when it came to me correcting them about the tongue not having specific regions for certain taste. It seems strange that such completely untrue statements can still be taught in schools today. Not quite as egregious is the biology lesson regarding the reproduction of a flower. I distinctly remember peeling a flower head apart in order to locate the stigma and the anther and so on. Most people would be able to tell you that flowers contain both the male and female components of reproduction; but is that true? In many cases it is, but species of plant that are separated into male or female individuals are certainly not uncommon and yet not a mention through most people’s school careerer.