Education & Technology

A Conversation with Drexel University’s Jean-Claude Bradley

1/9/2008

By Linda L Briggs

CT: Conversely, what are some things that work really well in Second Life?

JCB: One thing new that I’ve done this term is have students do a project in Second Life.

CT: Yes, you recently wrote in your blog that one of your students created a life-size model of a molecule as part of that. That sounded really cool.

JCB: Right. To be able to stand next to a molecule that is as tall as you are, and to have your teacher be able to walk around it with you and comment,… that’s pretty useful.

CT: How familiar are students with the technology?

JCB: Most students have never been on. You have to install software; it’s not very difficult, but if you’re not motivated, there’s going to be a lot of handholding. I don’t mind doing it for a few students, but I can’t do it for 175.

There’s a misconception out there that students are very tech-savvy and following all these blogs and wikis and Second Life. That’s not true. The vast majority have never been [to Second Life].

CT: That’s an interesting comment about not assuming that students have used these technologies. One of the criticisms of Second Life is that there’s a lot of flash around it, but there aren’t that many people really using it.

JCB: It’s not really a common experience right now for students. That doesn’t mean you can’t teach them, but certainly, you cannot assume that they can just do these things without guidance. That’s why I have workshops, and during them, I can … have students bring in a computer and just work with them for a couple minutes [if needed].

CT: Do you have advice for instructors who want to integrate Second Life into their course?

JCB: You should have a really good reason to do it. The best advice is to find another teacher who is actually using it, and try to experience what the student is experiencing. You’ll get some ideas and advice from that. I was just talking to another teacher an hour ago who might be doing some things in Second Life. She’s also an organic chemistry teacher. I told her, just send your students to Drexel Island; have them interact with my students, click around on the quizzes, and if you think it might make sense, you can spawn off from that.

A lot of people have bad experiences in Second Life because they don’t have a good reason for going there. It’s like having people go to the Internet without a Web address. You want to be guided. That’s the best possible scenario.

It’s just another tool. I wouldn’t teach exclusively on Second Life. We have WebCT Blackboard; I have my wiki; I have my blogs; and those things all have their strengths. You’ve got to leverage them all.

Read More:

• Drexel University
• Second Life
• Drexel’s Wiki on Second Life
• Bradley’s Blog on e-Learning

 

 We all know that turning off your computer when it’s not in use is a smart way to reduce carbon dioxide emissions and help fight against the effects of climate change.

In fact, if you leave your computer on 24 hours a day, it could be responsible for releasing up to 1,500 pounds of CO2 into the atmosphere every year. The flying-toaster screen saver is cool…but is it that cool?

But if you have to leave your computer on, here’s a way you can make up for it: By joining a distributed computing network that models the effects of climate change.

Distributed computing networks harness the unused power of thousands of personal computers to perform complicated tasks.

For instance, climateprediction.net is a distributed network run by Oxford University and other partners that helps climate scientists run climate models on networked computers when those computers are on, but are not running at full capacity.

Once you join the network, you will be asked to download a climate model from the website. It will then run automatically in the background whenever your computer is switched on. When the climate model is finished running, the results are automatically sent back to the site over the Internet for analysis.

Users are invited to watch the climate model process if they like, and are provided with a summary of the model’s results through climateprediction.net. Or you could simply let the model run and never think about it again.

Either way, “always on” computer geeks can now contribute to climate change solutions and keep their flying toasters.

There are about 10,000,000,000,000,000,000 insects on earth at any given moment. Seriously, that’s a real number. For every one of us, there are 1.5 billion bugs.

But some of them are so horrifying, just one is too many. Here are five you want to avoid at all costs.

 

Japanese Giant Hornet (vespa mandarinia japonica)

From: Japan, obviously.

Why you must fear it:
It’s the size of your thumb and it can spray flesh-melting poison. We really wish we were making that up for, you know, dramatic effect because goddamn, what a terrible thing a three-inch acid-shooting hornet would be, you know? Oh, hey, did we mention it shoots it into your eyes? Or that the poison also has a pheromone cocktail in it that’ll call every hornet in the hive to come over and sting you until you are no longer alive?

Think you can outrun it? It can fly 50 miles in a day. It’d be nice to say something reassuring at this point, like “Don’t worry, they only live on top of really tall mountains where nobody wants to live,” but no, they live all over the goddamned place, including outside Tokyo.

Forty people die like that every year, each of them horribly.

More scary shit:
Here’s how the Japanese hornet treats other insects (and would presumably treat us, if we were small enough). An adult hornet will fly miles to find some squishy shit to feed to its children. Often times, it finds its food in, say, a hive inhabited by thousands of bees.

What to do? Well, Vespa japonica sprays the nest with some of the acid/pheromone and brings in reinforcements, usually consisting of 30 or so fellow hornets. They then descend upon the beehive like an unholy plague of hell-born death engines and proceed to make this world a scary goddamned place. This is maybe 30 wasps against 30,000 bees and the 30,000 bees do not stand a chance.

Behold the hornets systematically seize them with huge, wicked jaws and literally fucking cut them apart, one by one by one by fucking one. In three hours, there are piles of limbs and heads and just fucking bits of things that could possibly have been alive at one point, and the hornets have stormed the hive and flown away with all the bee’s children. Who will then be eaten.

Nature is fucking hardcore.

 

Bullet Ant (Paraponera clavata)

From:
Rainforests from Nicaragua to Paraguay

Why you must fear it:
It’s a full inch long, it lives in trees and thus can and will fall on you to scare you away from its hive–the one you didn’t know was there, because it’s in a fucking tree. Before it does this, it shrieks at you. This ant, you see, can shriek.

It’s called a Bullet Ant because its ‘unusually severe’ sting feels like getting shot. On the Schmidt Sting Index, Bullet Ants rate as the number one most try-not-to-shit-out-your-spine painful in the entirety of the Kingdom Arthropoda.

Also–and we do feel the need to stress this–they fucking shriek at you before they attack.

More scary shit:
Are you the sort of person who likes to think of yourself as tough? A “badass,” perhaps? “Hard,” as they say?

Some of the indigenous peoples of the area use Bullet Ants as part of this initiation-to-manhood ceremony that they do. You know the kind we mean, with us it’s like, a big party and your relatives give you money and everyone loves you and is so proud of you? Yeah with them, it’s these special leaf sleeves with hundreds of bullet ants woven into them, stingers-inwards. They put them on and are immediately stung to holy fucking bejeezus by, and this is important, hundreds of Bullet Ants woven into the sleeves, stingers-inward.

The goal is to leave them on for 10 minutes, after which their arms are stiff, useless lengths of twisting agony, their bodies wracked with uncontrollable spasms for days. And in order to be actually pass the ordeal and become a man, they have to do it 20 fucking times.

 

Africanized Honey Bee (Apis mellifera scutellata)

From:
South and Central America, the American Southwest

Why you must fear it:
You know how you can spot one of these? You can’t. There is no physical way to determine the difference between an Africanized bee and a common European bee. None whatsoever.

You can, however, easily tell the difference based on their behavior. Regular bees will give you about nine seconds of being too close to the hive before deciding you’re a threat and then attacking you. So it’s pretty easy to just walk past them without any screams. And if you do get them after you, they’ll consider you to be ‘chased off’ after about 300 feet.

Africanized bees do not roll this way. They give you half a second of being too close before they decide it is time to completely fuck your shit up and empty the entire hive–tens, maybe hundreds of thousands of angry, angry bees. When you run, flailing and crying and soiling yourself while screaming “JESUS CHRIST I’M COVERED IN BEES,” they will chase you for over half a mile.

More scary shit:
Africanized bees owe their existence to science. Warwick E. Kerr created them in Brazil during the 1950s by crossing a European bee with an African bee. He wanted a bee that could live in the jungle. He got a bee that swarms by the hundreds of millions, is insanely territorial, mindlessly aggressive, has killed anywhere from a few dozen to a few thousand people. And, can live in the jungle.

And after they escaped and swarmed northward, it turned out they were a-OK with deserts, too. They’ll be in Montana by 2010.

 

Army or Soldier Ant (Eciton burchellii)

From:
The Amazon Basin. There’s other subfamilies living in Asia and Africa, but these are the most notorious.

Why you must fear it:
By now, you will not be surprised to hear that these ants are, in fact, fucking huge, with the soldiers reaching a half inch in length. You will also not be surprised to learn that they have massive, powerful, machete-like jaws half the length of the soldiers themselves. They’re notorious for dismantling any living thing in their path, regardless of size. They’re also completely blind, which for some reason makes the whole thing worse.

They’re called ‘Army’ ants because their entire colony, comprising up to and over one million insects, is a 100 percent mobile battalion. They don’t make permanent hives like other ants, no, they bivouac down in single locations just long enough for the queen to shit out thousands of eggs, while the soldiers spread out in wide fans daily in search of food (“food” here, means “anything moving”). Then the eggs hatch and they enter the dreaded swarm phase of their existence.

Much like the word “killer,” nature takes words like “dreaded” and “swarm” very, very seriously. They carefully pick up their larvae and go on the move, a near-solid mass of insect death and horror moving steadily and swiftly along the jungle floor, flaying alive and disassembling every living thing too stupid, slow or asleep to get the living fuck out of the way. There is no talk of painful stingers or ballistic acid here, no, this is terror of a far more primordial nature–the kind that simply flows over you by the hundreds of thousands and rips you apart with massive, unbelievably powerful jaws, utterly and literally blind to size and species, considering everything in their path to be a threat to the continuation of their colony.

There are reports of animals the size of horses being overwhelmed and shredded by them. Go stand next to a horse and then think about what that means for you.

More scary shit:
Army Ants are masters of wholly-organic, living architecture. For the good of the colony, the ants will use their own living bodies to build any conceivable structure necessary, latching on to each other foot-to-foot to create protective walls and ceilings against the ravages of the weather, bridges to cross otherwise impassable spans, whatever happens to be needed. (Can they form themselves into a crude catapult mechanism and launch themselves at prey? Not yet.)

There is no other living thing in the entire world that does this.

And, they’re blind.

Now, time for the disclaimer. If you are squeamish or have a weak stomach or value your sanity in any way, you may want to bail out now.

Okay, here goes…

 

Bot Fly (family oestridae, genus and species varies)

From:
Most species found in Central and South America, some species found all over the world

Why you must fear it:
Oh boy. Ohhhhh boy. Okay, Bot flies.

There are dozens of varieties of Bot Fly, they’re each highly adapted to target a specific animal, they have delightfully descriptive names like Horse Stomach Bot Fly, Sheep Nose Bot Fly and, hey, guess what. One of them is called Human Bot Fly. They each have a different and elaborate reproductive cycle, all of which end with a fat, half-inch maggot embedded in living flesh. Feeding.

Horse Stomach Bots, for example, lay their eggs in grass. Horses eat the grass. And the eggs. Which hatch in the heat of the horse’s mouth. Upon which they chew through the horse’s tongue and burrow, through the horse, into its belly. Where they meet up and dig honeycombs into the horse’s stomach. And get fat. When they’re ready to be flies, they just let go and get pooped out of the system.

The Human Bot Fly lays its eggs on a horsefly or a mosquito, something that will attempt to land on a human. This carrier finds a human and lands on him or her. The eggs rub off onto the human, whose body heat hatches the eggs. The larvae drop onto the skin and burrow right the fuck in. Where they live. Under your skin. Eating.

Here’s video of them removing one. DO NOT FUCKING WATCH THIS. Fuck, we don’t even know why we linked it.

More scary shit:
Here is the best part. The larvae can grow anywhere in your body, it just depends on where the eggs wind up. Which could end up with you having a fat wormy thing in your tear duct. Or your brain. We know, because that’s happened.

A Human Bot Fly larvae, burrowing into your brain. Eating your thoughts.

All this learning and fear remind you of high school? Head over to our video countdown of the 7 Scariest Teachers on YouTube. Or check out the blog, where Michael Swaim will tell you why you should be scared of the government too, and comes up with an awesome name for a rock band in the process.

Silicon, in the form of photovoltaic cells, is good at generating electricity from sunlight. New research shows that it could also make a good thermoelectric: a material that converts heat into electricity and vice versa. Since silicon is more abundant than the leading thermoelectric materials and has a vast manufacturing infrastructure behind it, it could eventually yield cheap devices for generating power from engines’ waste heat or from solar heat.

In this week’s Nature, University of California, Berkeley, chemistry professor Peidong Yang and his colleagues report having fabricated silicon nanowires that generate electricity when a temperature differential is applied across them. Until now, silicon has been considered a bad thermoelectric material. But according to Yang, “the performance of the nanowires is already comparable to the best existing thermoelectric material.”

Thermoelectric devices have been around since the early 1960s, usually made from either bismuth telluride or lead telluride. They are used mainly for cooling: when a voltage is applied across a thermoelectric material, it gets hotter on one side and cooler on the other. Thermoelectric coolers are popularly used in portable picnic coolers and cooling car seats.

But more exciting applications lie in energy efficiency and energy generation. Thermoelectrics could be used to convert waste heat generated by car engines into electricity. Even more attractive is the idea of thermoelectrics’ harnessing the sun’s heat to create electricity. But bismuth telluride and lead telluride are not efficient enough, so devices made from them are costly as well as bulky, because they require more material.

Thermoelectrics would have to be at least twice as efficient as they now are to be used for cheap power generation, says Mildred Dresselhaus, a thermoelectrics pioneer and physics and electrical-engineering professor at MIT. Using nanoscale structures instead of bulk crystals of the materials can increase their efficiency, she says. Nanostructures block the flow of heat but allow electrons to flow easily. But processing and nanostructuring bismuth telluride is not easy.

Silicon, on the other hand, “is much easier to process, has a big processing infrastructure behind it,” Yang says. “Silicon also has a much lower cost than bismuth telluride.” The problem with silicon is that it is a bad thermoelectric. A good thermoelectric needs to be two things: a good electrical conductor and a bad heat conductor. Silicon conducts both heat and electricity very well.

Yang and his colleagues reduced silicon’s thermal conductivity by using silicon nanowires. They fabricated an array of silicon nanowires that are between 20 and 300 nanometers in diameter. Nanowire synthesis often involves liquefying a nanoparticle and inducing it to grow, much like a hair. But that produces nanowires with smooth surfaces. The chemical etching method that Yang’s team uses results instead in nanowires that have rough surfaces. The researchers found that wires that are about 50 nanometers wide retain electrical conductivity but have only one-hundredth the thermal conductivity. This results in a thermoelectric efficiency close to that of some commercial bismuth telluride materials.

No current theory explains why the nanowires’ thermal conductivity goes down so drastically. One of the reasons, Yang believes, is that the nearly one-dimensional nanowires and the wires’ rough edges block the flow of phonons, which are particles that carry heat. But the complete picture remains unclear.

Ali Shakouri, an electrical-engineering professor at the University of California, Santa Cruz, says that researchers will have to understand how the physics works before they can improve the technology enough to produce commercial devices. Furthermore, using nanowires for energy conversion and power generation has its own limitations, Shakouri says. Such applications require large arrays of nanowires, but in the Nature paper, Yang and his colleagues measured the electrical properties of individual nanowires. The researchers will have to make sure that those properties translate to entire nanowire arrays, says Shakouri: “Variations and interactions between nanowires could take away some advantages.”

Still, he says, “this is important work that could have a big impact.” Shakouri points not only to the demonstration of silicon’s potential as a thermoelectric, but also to the unique engineering that the researchers used to make rough nanowires. “The new way of playing with material properties is very interesting,” he says. “It could open up a way to improve thermoelectrics that could be applied to other materials.”

Yang and his colleagues, meanwhile, are already thinking about how to improve their nanowires’ performance. They plan to reduce the size of the nanowires and make their surfaces rougher than they already are. That should enhance their thermoelectric properties, Yang says. The researchers also plan to make and test an actual thermoelectric device using silicon nanowires.