1 00:00:00,800 --> 00:00:03,360 Speaker 1: Welcome to How Stuff Works Now. I'm your host, Lauren 2 00:00:03,400 --> 00:00:06,240 Speaker 1: voc Obam, a researcher and writer. Here it has to works. 3 00:00:10,119 --> 00:00:12,360 Speaker 1: Every week, I'm bringing you three stories from our team 4 00:00:12,400 --> 00:00:16,040 Speaker 1: about the weird and wondrous developments we've seen in science, technology, 5 00:00:16,079 --> 00:00:19,360 Speaker 1: and culture. This week, there's a new polymer that can 6 00:00:19,400 --> 00:00:22,159 Speaker 1: stretch like a rubber band, supporting one thousand times its 7 00:00:22,200 --> 00:00:26,840 Speaker 1: own mass and hold that shape until warmed plus. Unrelated, 8 00:00:27,120 --> 00:00:30,400 Speaker 1: there's a black market for avocados in New Zealand. And 9 00:00:30,480 --> 00:00:33,239 Speaker 1: this is far from the first time that this has happened, 10 00:00:34,000 --> 00:00:37,120 Speaker 1: but First Senior writer Robert Lamb brings us a potential 11 00:00:37,159 --> 00:00:41,200 Speaker 1: memory boosting brain hack, one that doesn't even involve experimental 12 00:00:41,240 --> 00:00:48,720 Speaker 1: pills or neural implants. The key is apparently cardio. Dutch 13 00:00:48,840 --> 00:00:52,640 Speaker 1: researchers at rad Food University Medical Center conducted a seventy 14 00:00:52,640 --> 00:00:56,720 Speaker 1: two person study on exercise and memory consolidation. Specifically, we're 15 00:00:56,720 --> 00:01:00,160 Speaker 1: talking aerobic exercise such as running, and of all the 16 00:01:00,160 --> 00:01:04,120 Speaker 1: different forms of human memory declarative or explicit memory, a 17 00:01:04,160 --> 00:01:07,080 Speaker 1: form of long term memory that relates to facts and 18 00:01:07,240 --> 00:01:10,280 Speaker 1: verbal knowledge. We split the subjects into three groups and 19 00:01:10,400 --> 00:01:13,279 Speaker 1: each began the experiment with a forty minute learning session 20 00:01:13,400 --> 00:01:17,800 Speaker 1: during which they absorbed ninety picture location associations. Afterwards, they 21 00:01:17,800 --> 00:01:21,040 Speaker 1: all took a baseline memory test on the material. One 22 00:01:21,080 --> 00:01:24,360 Speaker 1: group immediately launched into a thirty five minute spin class, 23 00:01:24,520 --> 00:01:27,479 Speaker 1: and another way to four hours before hitting the stationary 24 00:01:27,520 --> 00:01:30,960 Speaker 1: bikes as well. The third group just set on their keysters. 25 00:01:31,600 --> 00:01:34,520 Speaker 1: Then forty eight hours later the research is called everyone 26 00:01:34,560 --> 00:01:37,920 Speaker 1: back in, tested their knowledge, attention and analyzed their brains 27 00:01:37,959 --> 00:01:41,080 Speaker 1: with a little m r I. Those who exercised four 28 00:01:41,160 --> 00:01:45,040 Speaker 1: hours after learning showed a marked advantage on the second 29 00:01:45,120 --> 00:01:49,560 Speaker 1: memory test. The study, published in the journal Current Biology, 30 00:01:49,800 --> 00:01:52,120 Speaker 1: stresses that there's much we don't know here. We don't 31 00:01:52,160 --> 00:01:56,200 Speaker 1: know why or how delayed exercise impacts memory consolidation, and 32 00:01:56,240 --> 00:02:00,320 Speaker 1: indeed the molecular mechanisms of consolidation are poorly under stood, 33 00:02:00,640 --> 00:02:02,880 Speaker 1: and four hours is just an experimental time frame. The 34 00:02:02,920 --> 00:02:07,720 Speaker 1: exact effective time frame for the delayed exercise boost is unknown. Plus, again, 35 00:02:07,760 --> 00:02:10,639 Speaker 1: we're talking about just one of several memory types here. 36 00:02:10,919 --> 00:02:14,360 Speaker 1: While this study focused on declarative memory tasks, a handful 37 00:02:14,400 --> 00:02:18,120 Speaker 1: of previous studies observed in immediate post exercise boost in 38 00:02:18,240 --> 00:02:22,640 Speaker 1: procedural memory tasks. If future studies support these findings, we 39 00:02:22,720 --> 00:02:26,919 Speaker 1: might gain new insight into the benefits of physical education classes. 40 00:02:27,040 --> 00:02:29,320 Speaker 1: But if nothing else, these signings get to drive from 41 00:02:29,360 --> 00:02:31,880 Speaker 1: the fact that the human brain is not a digital 42 00:02:31,880 --> 00:02:36,040 Speaker 1: computer and memory is not a comprehensive file of inputed data. 43 00:02:36,360 --> 00:02:39,640 Speaker 1: The brain is a hyper computer, memories are malleable, and 44 00:02:39,720 --> 00:02:48,600 Speaker 1: new information must be consolidated via a neurochemical process. Next up, 45 00:02:48,760 --> 00:02:52,760 Speaker 1: senior writer Johnathan Strickland has a material science story for us. 46 00:02:53,160 --> 00:02:55,919 Speaker 1: After all, why use engines to do work like pulling 47 00:02:55,919 --> 00:02:59,160 Speaker 1: weight when you can just apply gentle heat to a polymer. 48 00:02:59,720 --> 00:03:05,880 Speaker 1: A research team at the University of Rochester has created 49 00:03:05,919 --> 00:03:09,399 Speaker 1: an interesting new polymer. Oh and just in case you've forgotten, 50 00:03:09,440 --> 00:03:12,959 Speaker 1: a polymer is a long chain molecule consisting of repeated 51 00:03:13,120 --> 00:03:16,680 Speaker 1: smaller molecules. The one you're probably the most familiar with 52 00:03:16,840 --> 00:03:19,880 Speaker 1: is plastic. The team built a polymer that is elastic, 53 00:03:19,919 --> 00:03:22,840 Speaker 1: which means it can change shape. But unlike a rubber band, 54 00:03:22,919 --> 00:03:25,720 Speaker 1: which snaps back to its original shape once you let 55 00:03:25,760 --> 00:03:28,960 Speaker 1: go of it, this polymer holds the new shape, that is, 56 00:03:29,040 --> 00:03:31,320 Speaker 1: until you heat it up. When the polymer warms to 57 00:03:31,440 --> 00:03:35,400 Speaker 1: around human body heat temperatures, it returns to its original shape. 58 00:03:35,440 --> 00:03:39,000 Speaker 1: It can also lift one thousand times its own mass, 59 00:03:39,040 --> 00:03:42,200 Speaker 1: meaning this polymer can do work. Imagine stretching out a 60 00:03:42,280 --> 00:03:45,040 Speaker 1: large amount of polymer over a pulley and down to 61 00:03:45,080 --> 00:03:47,360 Speaker 1: a weight. Then you apply heat to the polymer. The 62 00:03:47,400 --> 00:03:50,880 Speaker 1: material will contract back to its original shape, lifting the 63 00:03:50,920 --> 00:03:55,600 Speaker 1: weight for you, no engine required. So what's going on here? Well, 64 00:03:55,680 --> 00:03:58,760 Speaker 1: when the polymer gets stretched, the smaller molecules in the 65 00:03:58,840 --> 00:04:01,880 Speaker 1: chain begin to form crystallites. That's another way of saying 66 00:04:01,920 --> 00:04:04,920 Speaker 1: they become stable in a new arrangement. That's why the 67 00:04:04,960 --> 00:04:07,760 Speaker 1: polymer stays stretched out even when you let it go. 68 00:04:07,960 --> 00:04:12,040 Speaker 1: Applying heat essentially breaks up the party, melting the crystallites 69 00:04:12,080 --> 00:04:14,480 Speaker 1: and the polymer. The whole thing contracts back to its 70 00:04:14,480 --> 00:04:18,640 Speaker 1: original form. The concept of a shape changing polymer isn't new. 71 00:04:18,800 --> 00:04:22,120 Speaker 1: It's also the basis of a technology called four D printing, 72 00:04:22,400 --> 00:04:25,360 Speaker 1: which relies on water absorption instead of heat to trigger 73 00:04:25,400 --> 00:04:29,359 Speaker 1: the change. But the Rochester team's polymer opens up new possibilities. 74 00:04:29,400 --> 00:04:32,800 Speaker 1: The team's primary focus is on the biomedical field. A 75 00:04:32,880 --> 00:04:35,560 Speaker 1: wound dressing that can apply pressure once it warms up 76 00:04:35,560 --> 00:04:38,520 Speaker 1: to body temperature is a typical example, but perhaps we'll 77 00:04:38,560 --> 00:04:41,960 Speaker 1: see non medical uses of this material further down the road. 78 00:04:42,240 --> 00:04:44,520 Speaker 1: Imagine a pair of jeans that are loose when you 79 00:04:44,520 --> 00:04:47,120 Speaker 1: put them on, but then get snug as the heat up. 80 00:04:47,720 --> 00:04:57,080 Speaker 1: My butt would look great in those. Finally, this week 81 00:04:57,120 --> 00:05:00,320 Speaker 1: I explain how in New Zealand avocados had joined rank 82 00:05:00,320 --> 00:05:03,400 Speaker 1: of all of the illicit, illegal and stolen goods available 83 00:05:03,400 --> 00:05:06,960 Speaker 1: on the black market. Avocado crime isn't all that uncommon. 84 00:05:07,320 --> 00:05:11,360 Speaker 1: You could say the fruit has a seedy history. Yeah. Nah, 85 00:05:11,800 --> 00:05:18,760 Speaker 1: here's a story. There's a crime wave in New Zealand 86 00:05:18,800 --> 00:05:23,400 Speaker 1: and its target is avocados. About forty large scale thefts 87 00:05:23,400 --> 00:05:26,080 Speaker 1: have been reported by farmers, with up to three hundred 88 00:05:26,120 --> 00:05:29,839 Speaker 1: and fifty avocados stolen each time. According to Radio New Zealand, 89 00:05:30,200 --> 00:05:33,599 Speaker 1: the illegitimate fruit is being sold locally at roadside stalls 90 00:05:33,600 --> 00:05:36,880 Speaker 1: and through grocery stores and restaurants at slightly less than 91 00:05:36,920 --> 00:05:40,440 Speaker 1: the market price, which has doubled over the past few months. 92 00:05:40,880 --> 00:05:43,840 Speaker 1: In neighboring Australia, there were reports of the fruit selling 93 00:05:43,880 --> 00:05:46,800 Speaker 1: for seven dollars a piece earlier this year. That's about 94 00:05:46,839 --> 00:05:50,479 Speaker 1: five dollars American. To prevent break ins, Brisbane grocers began 95 00:05:50,560 --> 00:05:54,840 Speaker 1: posting signs please note no cash or avocados are kept 96 00:05:54,880 --> 00:05:59,360 Speaker 1: on premises overnight. How did we get here as a society? 97 00:05:59,400 --> 00:06:02,719 Speaker 1: What dry lives this kind of black market activity. As 98 00:06:02,760 --> 00:06:06,200 Speaker 1: with any economic issue, it's supply versus demand. In this case, 99 00:06:06,279 --> 00:06:08,839 Speaker 1: weather conditions led to a poor crop right after a 100 00:06:08,880 --> 00:06:12,880 Speaker 1: boom in demand in and additional nineties thousand New Zealand 101 00:06:12,920 --> 00:06:16,320 Speaker 1: households began buying the fruit. According to a growers association 102 00:06:16,360 --> 00:06:20,760 Speaker 1: called New Zealand Avocado, desperate times lead to opportunistic measures. 103 00:06:21,360 --> 00:06:24,039 Speaker 1: And all of this is small potatoes compared to what 104 00:06:24,120 --> 00:06:27,520 Speaker 1: happened in California in the late nineteen eighties. After three 105 00:06:27,560 --> 00:06:30,760 Speaker 1: winters of freezes cut crops, short petty thievery gave way 106 00:06:30,800 --> 00:06:35,440 Speaker 1: to professional level heists. Organized crime ring stole ten million 107 00:06:35,640 --> 00:06:38,400 Speaker 1: dollars worth of fruit in a single year, about five 108 00:06:38,440 --> 00:06:41,000 Speaker 1: to ten percent of the California industry at the time. 109 00:06:41,520 --> 00:06:45,080 Speaker 1: The state hired full time avocado cops, who, in their 110 00:06:45,120 --> 00:06:48,799 Speaker 1: first year of operations alone uncovered two hundred and eighty 111 00:06:48,839 --> 00:06:52,120 Speaker 1: three thousand pounds of illicit fruit being sold on the 112 00:06:52,120 --> 00:06:55,080 Speaker 1: black market. The takeaway here is that it's up to 113 00:06:55,200 --> 00:06:58,279 Speaker 1: us as consumers to be wary. If a deal seems 114 00:06:58,320 --> 00:07:01,040 Speaker 1: too good to be true, it probably is a bit 115 00:07:01,080 --> 00:07:03,359 Speaker 1: of good news though so far the thefts in New 116 00:07:03,440 --> 00:07:06,120 Speaker 1: Zealand have amounted to only a couple of thousand avocados 117 00:07:06,120 --> 00:07:09,240 Speaker 1: out of the million that may be sold this season, 118 00:07:09,520 --> 00:07:12,280 Speaker 1: and new crops should stabilize the market over the next 119 00:07:12,280 --> 00:07:18,600 Speaker 1: few weeks. That's our show for this week. Thank you 120 00:07:18,800 --> 00:07:21,280 Speaker 1: so much for tuning in. Subscribe now for more of 121 00:07:21,280 --> 00:07:24,560 Speaker 1: the latest and strangest science news and since links to 122 00:07:24,560 --> 00:07:26,200 Speaker 1: anything you'd like to hear is cover in the future, 123 00:07:26,680 --> 00:07:31,360 Speaker 1: plus any suggestions you have for food related nonfiction. 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