Helaman 10

I recently read this passage and remembered a lesson that i learned while serving a mission for the Church of Jesus Christ of Latter Day Saints.

4 Blessed art thou, Nephi, for those things which thou hast done; for I have beheld how thou hast with unwearyingness declared the word, which I have given unto thee, unto this people. And thou hast not feared them, and hast not sought thine own life, but hast sought my will, and to keep my commandments.
5 And now, because thou hast done this with such unwearyingness, behold, I will bless thee forever; and I will make thee mighty in word and in deed, in faith and in works; yea, even that all things shall be done unto thee according to thy word, for thou shalt not ask that which is contrary to my will.
6 Behold, thou art Nephi, and I am God. Behold, I declare it unto thee in the presence of mine angels, that ye shall have power over this people, and shall smite the earth with famine, and with pestilence, and destruction, according to the wickedness of this people.
7 Behold, I give unto you power, that whatsoever ye shall seal on earth shall be sealed in heaven; and whatsoever ye shall loose on earth shall be loosed in heaven; and thus shall ye have power among this people.

The lesson is mostly unconnected with the content of the passage, but this records a promise and command given to one of God's prophets in The Book of Mormon. Before I went on my mission (I could have ben 10 or I could have been 18 - I don't remember) I remember my mom emphasizing that this was a meaningful passage to her and after that I always paid attention to it when i read it. By the time I was on my mission, this prophet's faithfulness was a primary influence in my daily behavior - i thought about this passage with frequency and aspired to the obedience that brought these blessings to the prophet.

I think that the background for the lesson was this: Several weeks before I came home I was trying to motivate a small group of missionaries to work very hard. I knew that they would be more motivated by recalling instruction they had received from the scriptures or elsewhere to work very hard, than they would by my account of this passage that was meaningful to me. So I asked each missionary to come to a meeting prepared to share a scripture that had influenced their day-to-day behavior on their mission.

When we held the meeting I was shocked that, rather than repeatedly hearing of the "unwearyingness" mentioned in the verses above, I heard passages that described other attributes that should guide the daily behavior of missionaries specifically and worshipful disciples, such as love for others, humility, etc. As I recall, the passages reflected the things that each individual had particular strengths in. As much as i should have known all of this long before, it powerfully taught me two things: 1) working hard was something i was very good at and thought hard about, but it wasn't the only thing missionaries needed to do to be faithful disciples. 2) everybody was already working hard according to what Heavenly Father ad impressed upon them.

Two simple things, but it was a powerful lesson to me.

Best Christmas Movie Dialogue

Favorite dialogue of all time in a Christmas movie? Youtube Skeletor and Christmas for a hilarious clip. Look for the ne that is about a minute and a half long. Gets me every time.

Merry Christmas!

Walking

This article is more useful to modellers than the casual reader (take hoe points for the non-modeller are that i look at where i'm going whie i'm walking and am more likely to fall in heavy crowds because of contact with others). But it is interesting to see that the way they can model pedestrian behaviors and what they're thinking it could be useful for (e.g. Robotics).

http://www.pnas.org/content/108/17/6884.full

Tragedy of the Commons

I promise to get back to what i started 2 days ago, but I'm short on time tonight, so i thought i'd paste n something from an article called "the Tragedy of the Commons."  it's an interesting read, though i disagree with his reasons for writing the article. Here's what the tragedy is:

"The tragedy of the commons develops in this way. Picture a pasture open to all. It is to be expected that each herdsman will try to keep as many cattle as possible on the commons. Such an arrangement may work reasonably satisfactorily for centuries because tribal wars, poaching, and disease keep the numbers of both man and beast well below the carrying capacity of the land. Finally, however, comes the day of reckoning, that is, the day when the long-desired goal of social stability becomes a reality. At this point, the inherent logic of the commons remorselessly generates tragedy.

As a rational being, each herdsman seeks to maximize his gain. Explicitly or implicitly, more or less consciously, he asks, "What is the utility to meof adding one more animal to my herd?" This utility has one negative and one positive component.

1. The positive component is a function of the increment of one animal. Since the herdsman receives all the proceeds from the sale of the additional animal, the positive utility is nearly + 1.

2. The negative component is a function of the additional overgrazing created by one more animal. Since, however, the effects of overgrazing are shared by all the herdsmen, the negative utility for any particular decision making herdsman is only a fraction of - 1.

Adding together the component partial utilities, the rational herdsman concludes that the only sensible course for him to pursue is to add another animal to his herd. And another.... But this is the conclusion reached by each and every rational herdsman sharing a commons. Therein is the tragedy. Each man is locked into a system that compels him to increase his herd without limit -- in a world that is limited. Ruin is the destination toward which all men rush, each pursuing his own best interest in a society that believes in the freedom of the commons. Freedom in a commons brings ruin to all."

Of all the elements in the periodic table, six are the most abundant in living organisms: carbon, hydrogen, nitrogen, oxygen, sulfur, and phosphorus. The goal of life is to obtain these elements in a form that they can be used in directly, or to synthesize them into a useable form. Also, once obtained, these elements are required for different things. Sometimes an organism needs oxygen because it is an element that is part of a structural molecule the organism is synthesizing (think - a starchy cell wall). But sometimes oxygen is necessary because an animal needs it to get energy out of it (for example, to power the building of that starchy cell wall).

The question is - what are the useable forms of those elements, and how are those useable forms created. For example, we don't make the vitamin B12 but we do require it to live. Is there an abundance of vitamin b12 on the earth already, or does it have to be made? If we don't make it, what does? How does it make it?

These are fundamental questions in biology, and an emerging theme is that eukaryotes (roughly, organisms with a nucleus, many of which are multicellular) aren't great at making their own nutrients. Single celled prokaryotes, different from eukaryotes n several ways includng being anucleate and unicellular, are great at synthesizing these molecules from materials that are not useful to humans. For example, Escherichia coli cells in the human astrointestinal tract synthesize vitamin B12 that we subsequently take up and use. The emerging model is that eukaryotes use prokaryotes n symbiotic associations to live in places they otherwise couldn't live because the prokaryotes provide nutrition to the eukaryote, just as in the example above.

More on this later - i was trying to build up to another cool association, but took too long getting there.

A good example

There are lots of really fantastic things about my wife, but one of my favorites is that she is really open about who she is. She's straight up with you and doesn't go out of her way to be nasty, but doesn't pretend to like what you're saying or agree with you if she doesn't like what you're saying or agree with you. I learned at some point that smiling and agreeing was an easy way out of situations i didn't care to invest myself in, and I've really learned a lot from her about being open and honest about yourself. I really appreciate her example in that way.

Sepiolid Squid Symbiosis

As a student in microbiology I ask questions about how beneficial
bacteria associate with animals hosts: how they associate, what
benefits are exchanged through the association, and why sometimes
specific bacteria are included in an association while others are
excluded. The spin and the angle is usually to relate this back to
humans (think: why are certain species of bacteria in our mouths or
our intestines?), but there are many associations that are interesting
to study either for the novelty of the association (microbes that
provide nutrition from hydrothermal vents on the ocean floor to
tubeworm hosts), or for purposes that have economic value of their own
(a classic example is how nitrogen-fixing bacteria interact with their
plant hosts to fix gaseous nitrogen, which plants can't use, into
compounds that plants can use for growth).

In the field of beneficial microbial associations there are a number
of model animal-bacterial associations that are studied to help us
understand how partners interact in a more complex association.
Complexity can be measured as many things, but one complex factor is
the number of partners in the association. Humans carry greater than
5,000 different kinds of bacteria in our intestinal tract alone, so if
we wanted to ask how or if a specific species is maintained within the
intestine, and how, that's a difficult question to ask. In a model
where there is one animal host and one partner, you know exactly who
to look and and that the selective pressures are strong (perhaps - who
knows? - stronger than the forces our intestinal cells exert on
microbes they interact with).

One of the classic models for asking questions about how hosts and
symbionts recognize and interact with each other is the association
between a specific squid species and a specific bacterial species.
Adult sepiolid squids are about the size of a golf ball and associate
with bacteria that produce light in a special organ (called the light
organ) on the ventral side of the squid. The squid collects bacteria
from the environment through a series of selective processes, and once
inside the light organ the bacteria produce light. The light organ is
flanked by reflective tissue and lens tissue similar to our eyes that
moderates the amount of light that is reflected from the dorsal side
of the squid.

What's the benefit of the association to each partner? The light organ
is a beneficial place for the bacteria since they can reproduce more
inside the squid than outside the squid, and can be spread more widely
when released from the squid than if they were not associated. The
squid uses the light produced by the bacteria in a really cool way to
counterilluminate its shadow. The squid actively feed at night and
burrow in the sand during the day. While active at night, predators
looking up to the ocean surface from below the squid would see a
shadow cast by the squid against the moonlight. Light production by
the squid counterilluminates the shadow, and some very nice work has
showed that if you shine brighter light above the squid it will put
out more light from the organ by controlling how widely the lenses to
the organ are open.

Its a pretty neat biological phenomenon, and is just one of the ways
that bacteria interact with their animal hosts in beneficial ways. One
interesting thing is that the squid recognizes its beneficial bacteria
in many of the same ways we recognize pathogenic bacteria. This and
other work is starting to blur the distinction between beneficial and
pathogenic interactions.