Understanding Basic Wireless Concepts

One of the many new blog mini-series I will be rolling out in the next month or two concerns wireless technology and networks.  It is something I am becoming more and more interested in for several reasons.  First, wireless is so incredibly relevant to our time that my intellectual curiosity has naturally led me to want to understand it.  Second, a couple of friends and I have recently noticed a large gap in the space, a technology that needs to be available, yet is not.  In order to properly bring this new technology into being, we need first understand what it is we will be working with.

So for the next few months, a series of posts will be entirely devoted to learning and teaching the basic concepts in wireless technology, from WiFi to cellular networks, from radio & television to the internet, and everything in between.

So stay tuned into Volumnomics to learn some more useful, relevant knowledge about the world around you.

This post will begin with a basic look into the essential components and concepts underlying wireless networks.

First let's look at data.  What kind of data can be sent wirelessly?  Anything really -- from radio and TV signals, to computer data, to even voices and sound bytes.  Radio wave piggybacking gets the information from point A to B.  I'll discuss the Electromagnetic Spectrum in further detail in another post soon.

So how exactly does the information piggyback onto the radio waves?  Well, to do this, we rely on a process called modulation.  We use a modulator to do this.  Naturally, this implies another process, on the receiving end, aptly named demodulation -- a crucial process for extracting the information after it is sent.

Information-piggybacked RF (radio frequency) waves are sent via transmitters and are received by, you guessed it, receivers.  

Cell technology works around the concept of the cell.  Cells are geographic areas divided into separate units. Cell phone communication begins within the cell where the phone resides.  If two cell phones are communicating within the same cell, no long-distance communication need take place.  However, longer distance communication requires more tools.

Every cell has a base station.  This base station acts as a transmitter, forwarding information from the cell phone to other transmitting base stations for as long as the information needs to travel.  The process of moving from cell to cell in this manner is commonly referred to as handoff.

Next post, we'll take a deeper look at the Electromagnetic Spectrum.  What is it exactly?  And why is it so incredibly relevant to every aspect of our lives?  

Is A College Degree Still Worth It?

Just read a good article in Bloomberg Businessweek, looking at this issue.  Chris Farrell does a nice job of examining the arguments.  Ultimately, his stance is for the  degree.  What do you think?

Click HERE to read the article.  

Revenge of the Glia

Glial cells... the most common type of cell in the nervous system.

Glia comes from the Greek word for glue.  Glial cells act as nervous system adhesives, keeping everything together and working properly.  They are non-excitable cells, which obviously means they do not produce action potentials.  This, in my opinion, is why neurons get all the attention, even though glial cells outnumber nerve cells many magnitudes over.

You'll find several types of Glia in the CNS.
1.  Oligodendrocytes (Schwann Cells in the PNS) act to sheath axons with myelin.
2.  Microglia, the guardians of the brain, are activated during an infection and after damage.  They are kind of like the janitors, cleaning up the mess.
3.  Astrocytes are the most common glial cells.  If I remember correctly, they make up 90% of all glial cells.

* I mentioned Schwann Cells briefly.  They can be myelinating or non-myelinating.  The non-myelinating type sits around the NMJ, providing necessary trophic support, regulating the function of the synapse.

Microglia:

These guys are the resident immune cells.  They are immediately activated post-injury, and are therefore hyperactive during neurodegenerative disorders.  Researchers think they may play a role in development as well.

Oligodendrocytes:

These are the myelinating cells.  They originate from the same stem cells as astrocytes and are implicated in demyelinating diseases such as MS.  Myelin proteins are known inhibitors of axon regeneration.

Astrocytes:


Astrocytes allow us to have a glialcentric view of the nervous system as well as a neurocentric one.  What do astrocytes do during neural development, exactly?  Just a few of the findings are as follows:
* RGCs can be cultured in the absence and presence of glia
* Glia increase synaptic activity
* Soluble signals released by astrocytes induce an increase in synapse numbers on RGCs
*Purified thrombospondin is sufficient to increase synapse numbers to the ACM levels
* TSP 1 and 2 expression is developmentally regulated.

So what are Thrombospondins?
They are proteins with antiangiogenic (inhibits the growth of new blood vessels) abilities.  The acronym is TSP.  TSP 1 and 2 are expressed by developing astrocytes, with TSP4 being expressed at the NMJ.  They regulate cell attachment, the cytoskeleton, migration, and of course angiogenesis.

But most importantly, they are synaptogenic, meaning they induce synapse formation.  Synaptogenic function is mediated through an EGF-like domain.  The drug Gabapentin specifically blocks synapse formation induced by TSP, by the way.  Drugs like this (Neurontin and Lyrica) are used to treat chronic pain and epilepsy, but their actual mechanism of action is unknown.  I'm pretty sure they were developed with the intention of blocking the Ca2+ channel subunit that acts as the receptor for Gabapentin & Pregabalin (*note the GABA theme here) but didn't end up doing the specific molecular action that the scientists initially desired (isn't this how basically every drug is developed, as a failure turned multi-billion dollar miracle pill?  read...Viagra).

Intermittent Fasting: Healthy or Harmful?

Healthy!  Resoundingly healthy.

Check out these sites for a comprehensive look at IF:

http://www.leangains.com/

-Martin here has a great story.  He is a nutritional consultant, writer, and personal trainer.  Be sure and check out the testimonials and success stories from his clients.  Guaranteed, you'll be blown away.

 http://www.marksdailyapple.com/health-benefits-of-intermittent-fasting/ 

- In my opinion, Mark has the premier site up now at MarksDailyApple when it comes to all aspects of Primal/Paleo eating and living.  He is incredibly well-spoken  and thorough in his posts and research.

http://www.eatstopeat.com/index2.shtml

-Brad has also got a good thing going with his book "Eat Stop Eat." He advocates including one or two 24 hour periods a week where you fast, both for fat loss and health benefits.  

http://robbwolf.com/

- And be sure to check out Robb's work.  He has a great site and just wrote the book "The Paleo Solution: The Original Human Diet."  In it you can find some great advice and information on fasting.

Asymmetric Cell Division and Neural Stem Cells

This post will examine several things:
1.  What are stem cells? and what is ACD?
2.  What are the important features of ACD?
3.  Examples from model organisms.
4.  Diseases.

There are many different types of stem cells in our bodies.  Stem cells go on to produce specific cell populations in development.  For example, the ectoderm gives rise to neural stem cells which proliferate into neurons, skin, hair, and the mammory glands.

Stem cells have several properties.  First, they must be able to self-renew.  Second, they must possess a certain potency.  That is, they need to have the ability to divide to produce differentiated cells.  Totipotent stem cells can go on to produce every type of cell.  Pluripotent and multipotent stem cells are more limited in the cell populations that they can proliferate into, but they can still give rise to a large diversity of different cell populations.

Asymmetric cell division is the division of one cell that gives rise to two cells with different fates.  Normal cell division gives rise to two cells of equivalent fates.  Stem cells divide asymmetrically, giving rise to two distinct daughter cells, a copy of the original stem cell as well as another daughter with a non stem cell fate.
Centrosomes and the mitotic spindle play a key role in whether cells differentiate from the stem cells or not.

So how do stem cells divide?  Well, several factors come into play.  First, polarity cues provide the signal to divide or not.  There are both intrinsic and extrinsically-activated cues.  We also have asymmetrically localized determinants - cell polarity determinants and fate determinants.  Some common fate determinants are proteins (Numb being a key protein in determining neuronal fate), RNA, DNA, asymmetric phosphorylation, and organelles.  Mitotic spindle apparatus orientation also plays a big role.

Steps in ACD:
- Interphase: Setting up axis of cell/ Polarity cues
- Pro-metaphase: fate determinants segregated
- Metaphase: Mitotic spindle orients in cell
- Telophase: light coordination segregates components to different cells.

We can study stem cells in most of the common model organisms.  For example, big strides are being made in stem cell research in C. Elegans, yeast, C. Cerevisae, Drosophila, and mice (neural stem cells).

Neural stem cells function to produce neurons.  You can find them in both the PNS and the CNS.  They can include both pluripotent stem cells and multipotent progenitor cells.  And they can be found both during development and during adult homeostasis, interestingly enough.    

The Viral Me

Here's the link to GQ's article The Viral Me.  It is an honest look at the start-up scene and how it drives our new compulsion to take much of our lives into social media.

http://www.gq.com/news-politics/big-issues/201012/viral-me-silicon-valley-social-networking-devin-friedman

TEDx - Simon Sinek: How great leaders inspire action

It's not what you do; it's why you do it.