9 October 2017
Braiding Sweetgrass is a collection of thematically-linked essays by Robin Wall Kimmerer, an environmentalist, academic, and Native American. The themes that unite them are plants, the human relationship to the natural world, and love. I’ve read Kimmerer’s essays in Orion before, but there’s a sort of literary force multiplier when you get a whole book full of her thoughtful insights, story after story, back to back. Braiding Sweetgrass is a work that reminds me of Annie Dillard’s or Barbara Kingsolver’s nonfiction, with the additional flavor of indigenous insight woven (or maybe “braided?”) in. The key aspect of this indigenous insight is a consciousness of the human role in a larger dynamic ecosystem – the valid and valued role that human beings can engage in if they choose to, to the benefit of both their own selves and the natural world as a whole. For instance, in a section about a basket-making lesson, Kimmerer recounts how the students had dropped scraps of ash wood (long fibers called “splints”). In describing her teacher John’s reaction, she says:
In a circle around each novice is a litter of scraps. [John says] “Stop and think what you’re holding. That ash tree was growing out there in that swamp for thirty years, putting out leaves, dropping them, putting out more. It got eaten by a deer, hit by a freeze, but it kept working year in and year out, laying down those rings of wood. A splint fallen on the ground is a whole year of that tree’s life and you’re about to step on it, bend it, grind it into the dirt? That tree honored you with its life. There’s no shame in messing up a splint; you’re just learning. But whatever you do, you owe that tree respect and should never waste it.” And so he guides us as we sort through the debris we’ve made. Short strips go into a pile for small baskets and decoration. The miscellaneous bits and shavings get tossed into a box to be dried and used for tinder. John keeps to the tradition of the Honorable Harvest: take only what you need and use everything you take.”
As with basket-making, this is excellent perspective to maintain in Life In General. But Kimmerer is a plant scientist too, and she shares fascinating research about how human harvest of black ash actually helps (rather than hurts) the trees’ population, one of those counter-intuitive revelations from ecology that remind us why we practice the scientific method instead of just assuming we know what’s going on with the world.
Kimmerer’s locations in the book are mainly centered in upstate New York, but there’s also time spent in the deep South, the Pacific Northwest, and other spots. Her career has had her travel, and she has relevant experiences accrued in each location, even if the woods and lakes of New York are her home.
The writing is eloquent and evocative. I was particularly taken with her description of Pacific salmon feeling the urge to quit the sea, head inland, and spawn:
Far out beyond the surf they felt it. Beyond the reach of any canoe, half a sea away, something stirred inside them, an ancient clock of bone and blood that said, “It’s time.” Silver-scaled body its own sort of compass needle spinning in the sea, the floating arrow turned toward home. From all directions they came, the sea a funnel of fish, narrowing their path as they gathered closer and closer, until their silver bodies lit up the water, redd-mates sent to sea, prodigal salmon returning home.
That’s just great description, but I feel Kimmerer really hits her stride when she’s make explicit connections between the natural and human worlds. (Of course, she sees these two as the same, or they should be the same, but she also knows she’s writing for an audience of humans who have been cut off from deep connection with the natural world through their own choices or Society’s.). Here’s Kimmerer on the Umbilicaria lichen, for instance:
The first drops [of rain] splatter hard against the rigid surface of rock tripe, which instantly changes color. The mud-brown thallus becomes sprinkled with clay-gray polka dots, the tracks of raindrops, which deepen over the next minute to sage green, like a magic picture developing before your eyes. And then, as the green spreads, the thallus begins to move as if animated by muscle, stretching and flexing as the water expands the tissue. In a matter of minutes it is transformed from a dry scab to tender green skin, as smooth as the inside of your arm. … Where the umbilicus anchors the thallus to the rock, the soft skin is dimpled, with little wrinkles radiating about its center. It looks to all the world like a belly button. Some are such perfect little navels that you want to kiss them like a little baby tummy. … As the lichen gets older, it becomes asymmetrical, the bottom half as much as 30 percent longer than the upper, a legacy of lingering moisture that permitted it to keep photosynthesizing and growing after the top half was dry and still. The trough can also collect debris, the lichen equivalent of belly-button lint. … Event the tiny thalli are dimpled with navels. How fitting that this ancient being, one of the first forms of life on the planet, should be connected to the earth by an umbilicus. The marriage of alga and fungus, Umbilicaria is the child of earth, life nourished by stone.
The book’s longest essay is on the legacy of pollution in Lake Onondaga, but others focus on harvesting maple sap for syrup, the different kinds of fire, teaching students in the Great Smoky Mountains, motherhood, rescuing salamanders, and climate change. There’s plenty of diversity of topical material, but her treatment is consistent – both the natural ecosystem and people do better when we cooperate. It behooves us to learn the ways of nature, and to envision a role for our own species to play in that larger system.
6 October 2017
Here’s a cool fold pair that rolled through my Twitter feed today:
2nd day Appalachian field trip. Recumbent isoclinal folds on a clear morning at Sauratown Mtns window NC pic.twitter.com/sHkmbp6roh
— Joe Allen (@CU_in_the_field) October 6, 2017
Joe Allen gave me permission to share it with you here. Here’s the photo with bedding traced out (by me) in yellow:
Happy Friday, all!
29 September 2017
For your Friday fold delectation, I offer you these GIGAmacro images of thin sections of the exquisite mass transport deposit (MTD) above the Spechty Kopf Diamictite (latest Devonian) in the exceptional roadcut just east of the Alleghany Front along Corridor H in Hardy County, West Virginia. This was a package of interbedded sand and mud that collapsed into deeper water en masse, deforming internally as it went. This is soft-sediment deformation, not post-lithification tectonic deformation. We dubbed the folded sandstone bodies “ploudins,” as they were sort of half “pillow” (as in ball & pillow soft sediment deformation) and part “boudin” (as in boudinage). Explore the ploudins’ internal structure these enormous images of the slides under plane and cross-polarized light. Search for graded bedding, cross-bedding, folding, faulting, organic debris (carbonized plant scraps), and maybe even a zircon or two. These images are Flash-based, so if you don’t have Flash, you can’t see them. Enable Flash on your browser, or click the “link” after each one to go to a non-Flash source page.
Here’s an annotated “cheat sheet” to guide your eyeballs on the first one:
These slides were prepared by John Weidner, a former math professor and a dedicated volunteer in our department.
Here’s a GigaPan of slide JW46 under cross-polarized light:
Link 2.19 Gpx GIGAmacro by Robin Rohrback & Callan Bentley
Here’s a GigaPan of slide JW46 under plane-polarized light:
Link 2.71 Gpx GIGAmacro by Robin Rohrback
Here’s a GigaPan of slide JW45 under cross-polarized light:
Link 2.10 Gpx GIGAmacro by Robin Rohrback
Here’s a GigaPan of slide JW45 under plane-polarized light:
Link 3.22 Gpx GIGAmacro by Robin Rohrback
My former student Maddy Rushing and I have been working on a characterization of this outcrop which we plan to present at GSA in Seattle next month. We’re using these sort of images as well as some other new digital toys to more fully describe and interpret the outcrop, in particular the Spechty Kopf Diamictite, which appears to be glaciogenic. But once you throw in plant fossils, changing oxidation states, and a mass transport deposit, it all starts to look a wee bit more complicated. Another volunteer in our department, Sarah Yun, has just completed a new suite of thin sections of the diamictite’s massive and laminated members. I can’t wait to show them off! If you’re available, Maddy’s talk on this work is Monday at 4:55pm in Bryan Turner’s and Shannon Dulin’s mud rock session. Please come!
22 September 2017
It’s the First Friday of Fall!
Here’s a sort of fold to help you celebrate: a section through a ∧ shaped bend in a vesicular basalt flow from the eastern flanks of Mount Etna in Sicily. It’s due to volcanic lava flowing rather than ductile deformation of a pre-existing solid rock (our usual habit with this feature), but I think we can appreciate it regardless:
20 September 2017
This past spring, when I attended the InTeGrate workshop called “Teaching About the Earth Online,” one of the participants recommended the book Make It Stick, by Peter Brown, Henry Roediger and Mark McDaniel. Months later, the volume finally moved up in my reading queue to the top. It’s a fascinating account of the empirical research about how people successfully learn. I found it absolutely engaging and stimulating, in particular the first several chapters. Much of how we think about learning and teaching is based on myth and lore, and several widely-deployed practices are not supported by scientific study.
The book’s big revelation for me is that testing (or quizzing) is a learning strategy. Durable learning results from effortful “retrieval practice.” Educators like me can embrace this realization by frequently deploying scheduled low-stakes quizzes, either before or right after the lesson, and giving feedback. If “before the lesson” sounds bizarre for the scheduling of a quiz, that’s exactly why you should read this book. Many of its lessons are counter-intuitive. But research shows that struggling with a problem before being taught how to do it, while frustrating, actually results in better assimilation of the lesson once the instructor teaches it. This is the beauty of the Make It Stick philosophy: Hard work is hard. But it works better than illusory learning that feels easy. The standard practices of re-reading chapters and highlighting them over and over and cramming before the test may feel like you’re learning, but you’re really just building familiarity with the text, or your lecture notes. This is called “massed practice,” and the authors of Make It Stick assert that you should stop wasting your time on it immediately.
Another shocking revelation along this same theme — “make it difficult” — is that if the text that a student is reading is made slightly blurry, or is presented with a word missing out of each sentence, the extra work that the brain has to do to make sense of the text actually results in better understanding of the concepts, and better recall. How crazy is that? Professors and teachers, you should make a special effort to present lecture material in a different order than the textbook presents the material. The extra effort students have to make to parse the different orders forces them to discern the underlying concepts rather than just a clever turn of phrase their professor puts on the book’s content.
Failure should be embraced as part of this process, but we need to change how we think about it. It’s not a reflection of the student’s inner worth or inability, but a curve in the road to success. Envisioning failure this way, as something to be accepted and conquered, is essentially an attitude change. It becomes a tool for mastery, an essential experience that should be looked forward to — and learned from. Perseverance in the face of failure is key to success. Failed tries are useful information to the dedicated learner.
The book’s chapters are written in a good mix of anecdote and peer-reviewed empirical research. Two of the authors are education researchers, but the lead author, Peter Brown, is a storyteller and writer. The stories he tells to open each chapter range in focus from business people to surgeons to pilots and sports coaches and active duty military. In each case, there are elements of each protagonist’s story that illustrate a key lesson from educational research, with the descriptions of the actual studies following the more compelling human tale. There’s rather more sports talk than suits a non-sporty person like me, but even I could choke it down.
The second half of the book was less compelling to me, perhaps because I was already familiar with some of the ground it covered: the Dunning-Kruger effect, Bloom’s taxonomy, the fraught idea of Multiple Intelligences & learning styles, memory palaces and other mnemonic devices, the general psychology/neurology of learning. However, the final chapter ties it all together with specific advice for various populations (students, teachers, trainers) and that I saw as a really useful distillation of the book’s main lessons.
Students, for instance, will be reminded that their number one strategy for more effective studying is not re-reading the chapter with highlighter at the ready but instead to initiate a program of self-quizzing. Making mistakes is to be an expected part of this process, so long as the students learn from those mistakes and refocus their efforts on the portions of the material where their performance is sub-par. Use a quiz such as the “Concept Checks” or end of chapter review in the textbook, or make up your own quiz. Convert the key points into questions, and then answer them. Syntax gets too much attention; you should focus on the underlying precepts. As you read, pause every couple of chapters and quiz yourself on what you just read. This will seem slow and clunky at first, but the effort you expend will be rewarded. More effortful recall results in a better-trod pathway of the mind, and more durable learning. Review your self-quiz results and do it again. And again. Write your answers out for real, don’t just dismiss a given question with “Yeah, I know that one.” Space your effort out in time, and mix it up with other related activities. Elaborate on the ideas you learn; don’t just parrot the same language in which the book presents material. Fluency with the text generates an illusory sense of mastery – but you don’t want to know the text. You want to master the underlying ideas.
All told, I think Make It Stick is going to revolutionize the way I teach; in particular with regard to frequent scheduled low-stakes quizzing.
15 September 2017
Samuele Papeschi has contributed another Friday fold for our delectation:
He describes this outcrop as:
East-verging folds in a dextral shear zone at Neves Glacier, South-Tyrol, Italy.
Thanks for sharing, Samuele!
If anyone else has a Friday fold to share, please get in touch!
Happy Friday to all. Enjoy your weekend.
13 September 2017
A new book on artificial intelligence (AI) has just been published. It’s Life 3.0: Being Human in the Age of Artificial Intelligence, by MIT physicist Max Tegmark. Tegmark was one of the trailblazing thinkers interviewed by James Barrat in his book Our Final Invention, which I thought was terrific, so I was eager to see what he had to say when writing for himself. I finished the audiobook version of Life 3.0 on my commute home last night. It’s good.
Tegmark is the founder of the Future of Life Institute (FLI), a nonprofit dedicated to helping life toward a better future by cultivating conversation and knowledge about existential threats, including nuclear war, climate change, biotech pitfalls, and AI. Mostly so far, FLI has focused on AI. They organized two successive conferences on AI safety and achieved a kind of consensus in the AI community with several documents that outline a vision for AI safety and key research questions that need to be addressed before an artificial general intelligence is developed.
Tegmark’s perspective is determinedly optimistic. He envisions life as having three stages:
Life 1.0: initial replication, like microbes (initiated ~3.5 billion years ago), which is driven by biological evolution;
Life 2.0: consciousness, like humans (initiated ~2 million years ago), which is driven by cultural evolution; and
Life 3.0: artificial general intelligence and superintelligence (likely to initiate ~10s to 100s of years in the future), which is driven by technological evolution.
This is typical of the “big picture” way that Tegmark thinks, zooming way out to look at the biggest of big patterns, and searching for the leanest, most parsimonious and inclusive definitions. He organizes his thinking around such “simple” themes, but dives into tremendous detail as he explores them. For the most part, his book communicates his ideas in a clear, engaging fashion. For instance, he offers an analogy from computers to help visualize his sequence of milestones in life’s evolution: Life 1.0 (everything from E. coli to Pan paniscus) has both its hardware (body) and software (behavior) encoded by genes, with upgrades taking place courtesy of natural selection over generations, for populations. Life 2.0 (us) on the other hand, is stuck with the hardware its inherited, but can upgrade its software through learning, and we can do that for an individual, within a time shorter than its lifespan (for instance learning how to change a car’s sparkplugs in a few minutes by watching a YouTube video). Life 3.0 (AI) will be able to upgrade both its software (copying and pasting, installing new programs, etc.) and its hardware (by building robotic bodies with any sort of toolkit needed) as it finds the need to do so.
In part of the book, he explores a great many future scenarios, some better and some worse (some catastrophically bad). He begins in the Prologue with the story of a Silicon Valley startup that is the first to make an artificial superintelligence, and how they use it to first make a lot of money and then to take over the world. But it stops before you find out what the start-up folks do with their new power. Later in the book, he returns to their story, and finishes it in a bunch of different ways, like how the Clue movie had several different endings. These scenarios are diverse, and involve many factors including a lot of hypothetical technology that arrays them along a spectrum of plausibility in addition to frightfulness. Throughout, Tegmark remains a sober but enthusiastic analyst. There’s no “Terminator/Skynet” scenario in this list. It’s not malice we have to fear from AI, he argues; it’s competence.
This leads to a discussion of what our toolkit looks like at this point: tools to prevent the worst from happening and promote the best to happen. Verification, validation, and security are each examined in turn. One thing that I found distinctive about Tegmark’s book as opposed to Nick Bostrum’s or James Barrat’s was his emphasis on how the pitfalls of modern technology might apply equally well to AI. Bugs in software cause all kinds of hassles in the modern world. What if our superintelligent AI gets a bug: Can we reboot it? And then there’s hacking: malicious humans can hack all sorts of things in the modern world: will they be able to hack other people’s AI too?
Another intriguing thread in the conversation came through Tegmark’s discussion of our cosmic endowment – the relationship of life to the universe. He argues that life, specifically conscious* life, gives meaning to an otherwise dead cosmos. Whether it’s biological life 2.0 or it’s AI, what’s the point of the world without living intelligence? Tegmark sees the ultimate value of figuring AI out right to be nothing less than the fate of the universe. One way to look at Life 3.0, he says, is as our evolutionary children: watching AI go forth into the cosmos as proud (but ultimately outclassed) aging parents. I’m used to thinking about “AI going to space” as a question of human responsibility, but this positive spin on it made me feel better.
He also raised the intriguing notion that if other technological civilizations elsewhere in the cosmos have developed artificial superintelligence, we should perhaps be very wary of any signals we might get from them. After all, if they didn’t do it right, perhaps their spacefaring AI might wreak their mistakes on us. For instance, what if we received a computer program from a distant star, sent as an encoded beam of light? If we run such a program (think Contact), we might be installing an alien superintelligence on our computers, only to have it begin working to convert Earth’s matter into a series of radio antennae – thereby broadcasting the ultimate malware to still further corners of the cosmos, and at the speed of light. Yikes: we need to protect the universe from a bad AI spawned by us, but we also have to potentially protect ourselves from bad AI spawned elsewhere, perhaps billions of light-years away, perhaps billions of years ago.
* Significant time is given over to exploring if machines could be conscious by exploring what neuroscientists think consciousness really is, and how we might measure it in other entities to verify its presence or absence. This is a critical point for Tegmark, because only if AI is conscious do questions of ethics become relevant (as applied to the machines themselves). Consciousness is a prerequisite for happiness, and if our goal is to maximize happiness in the future, the first goal must be to retain consciousness in an imperiled future.
I came away with a sense that Tegmark must be a very organized teacher, since his chapter structure is essentially: a) tell you what I’m going to tell you, b) tell you and elaborate, and c) recap what I just told you. At the conclusion of each chapter, there’s a “Bottom Line” paragraph that economically summarizes each chapter’s key points and these make a terrific summary of the book that would fit into two or three pages.
In the Epilogue, he shares the story of developing FLI: it’s a useful way of wrapping things up, because it brings in his personal intellectual journey in thinking about (and acting about) AI and ends in a much more hopeful, positive place than it begins. AI is the finish line in a race, and no one knows how far away that finish line is. But many people are running. We want to be ready when one of them crosses that finish line, and we find our intellects matched by (or dwarfed by) something that is not a human. Tegmark asserts that you and I are guardians of the future of life, and we need to be talking now about how we want the aftermath of this race to turn out. His emphasis in Life 3.0 is: think about what you want from AI. If you don’t know what you want, you’re unlikely to get it. So let’s start talking about it.
8 September 2017
An earthquake occurred overnight in southwestern Mexico, inland from the Middle America Trench, a subduction zone where the Cocos Plate (oceanic lithosphere) is being shoved down and under the North American Plate (continental lithosphere at this location). The Cocos Plate is being generated today through seafloor spreading at the East Pacific Rise, and is being “recycled” into the mantle beneath southwestern Mexico and Central America.
The quake was very powerful at magnitude 8.1, releasing lots of energy that has accumulated between the two plates as they have been shoved together over a long time. These sorts of convergent plate boundaries accumulate tremendous energy over years and years of relative motion, but the actual movement releases all that energy at once, when the strength of the rock is finally overcome, and a fault rips open (or the friction of a pre-existing fault is overcome, and it slips). (The same sort of situation happened in Japan in 2011, with even more energy released.)
The subduction zone is manifested in southwestern Mexico with a deep-sea trench where the two plates meet and a chain of volcanoes inland a ways into the overriding plate. El Chichón, Tacana, Popocatapetl, Colima, Pico de Orizaba, and Parícutin are some examples of the volcanoes that result from this subduction zone.
Here’s a general diagram showing such a setting, from the USGS. View it as if you’re looking northwestward, along the axis of the subduction zone, with the Cocos Plate on the left (southwest) and the North American Plate on the right (northeast):
The major earthquake that occurred last night was not a unique or one-off event. The area is known to have lots and lots of earthquakes over its long history of human habitation. Here are historical examples illustrated as white and gray dots:
The white dots are more shallow (less than 70 km depth), whereas the gray dots (harder to see) are deeper, greater than 70 km depth. The orange star is last night’s quake. It happened at about 71 km depth [this has been revised since I wrote the first draft of this post]. Note how the white dots parallel the trench in a linear zone, and the gray dots do the same thing, but further away from the trench: That is the signature of the subducted Cocos Plate “diving” down and to the northeast beneath Mexico, getting deeper as it makes its way along. Our new quake is right at the map key’s cut-off between “relatively shallow white dots” and “relatively deep gray dots,” and conveniently plots between the two major belts of dots on the map.
[UPDATE] Jascha Polet of Cal-Poly Pomona posted these useful diagrams on Twitter this morning, showing “beach ball” plots for many, many earthquakes in this region, and a cross-sectional plot showing the descending slab:
Seismicity cross-section of M8.2 quake: occurred in region with similar intraslab quakes, inland & at greater depth than interface thrusts pic.twitter.com/3yb47GUBIB
— Jascha Polet (@CPPGeophysics) September 8, 2017
Here, red is shallow, and blue is deep, and orange and yellow are somewhere in between. Notice how the “beach balls” look different from the side view as compared to the map view. Visualize them as spheres, sliced into four wedges apiece: two compressional (colored) and two extensional (white). With the white on “top” of last night’s quake, it looks like we have “normal” fault motion responsible for the shaking. This is a little counter-intuitive, given the larger tectonic context, but as you can see from Jascha Polet’s map, it’s pretty consistent with the historical trends in that zone. It’s a normal fault within the subducting slab.
The USGS’s PAGER program, an automated system that compares the size of a given earthquake with the local population density and state of development, estimates between a 1000 and 10,000 deaths from this quake as most likely, as well as significant economic losses (a billion to 1o billion dollars). There is a tsunami threat to Pacific nations and islands in the region: See tsunami.gov for more details.
There is no relation between this earthquake and Hurricane Katia, which is menacing the Gulf coast of Mexico at the same time. They are separate events, one driven by heat from Earth’s deep interior (the earthquake, which results from plate movement) and one driven by heat from the Sun poured onto Earth’s surface (its oceans and atmosphere: the hurricane). I know it seems like there’s a lot of natural disasters going on right now, with a trio of hurricanes in the Atlantic Basin, wildfires raging through the western part of the continent, and now this major earthquake. But though our natural tendency as humans is to look for patterns in natural observations, sometimes that tendency can lead us to draw causative connections where none really exist.
An earthquake this large changes the stresses acting on the rocks in the whole region, and aftershocks are going to happen as a result of readjustments. Expect more shaking in southwestern Mexico for the immediate future.
I was transferring some samples into my structural geology cabinet last week when I found this beautiful ptygmatic (“intestine-like”) folded quartz vein. I thought it deserved some wider circulation. I can’t recall where it came from, but it’s beautiful, with a train of a dozen or so isoclinal folds. So I made the digital media you see below. Enjoy!
Here’s a GIGAmacro of the sample (you need Flash enabled to view it):
Link 0.8 Gpx GIGAmacro by Callan Bentley
And here’s a 3D model of it:
1 September 2017
Well, I did it again: I read another Neal Stephenson novel. As noted in this space previously, I really enjoyed Seveneves, but was relatively underwhelmed by Cryptonomicon. In discussing these other books with friends, Snow Crash was recommended as the ne plus ultra of Stephenson’s style. In terms of coherence of plot and interesting characters and overall satisfaction, Snow Crash is up there with Seveneves, but I would still have Seveneves on the top of the pile because of its explicit science and relevance to the survival of the human race. There was something essential about that which really appealed to me. But Snow Crash is clever and hip and fascinating and feels current in spite of the fact that it’s actually 25 years old (first published in 1992). This book envisioned massively-multiplayer video games, popularized the term avatar, and envisioned a sort of virtual reality Google Earth almost a decade before Keyhole launched. It’s a prescient work on the technological front – perhaps as a result of its own influence on the programming community. Stephenson’s writing is something to behold – it’s so smart and creative. Regardless of plot or characters, his books are worth reading for the writing style alone. His vision of the future is idiosyncratic and fully-developed and provocative. Briefly, the plot of Snow Crash is that a swordsman and computer hacker uncovers a plot to resurrect a sort of “computer virus” that attacks the neurophysiology of the human brain-stem via spoken language or the visual representation of those words. In the history of the novel, this first became an issue in ancient Sumer, and the story of the Tower of Babel was a reaction to this debilitating meme – by breaking the world’s population up into sub-populations with mutually incomprehensible language, humanity was delivered from the unimpeded spread of the linguistic virus. But now that we’ve all converged on binary code as a technological lingua franca, a bad guy wants to release it anew for his own nefarious ends. There’s a lot more to the novel than that: the Mafia is a corporation, skateboarding couriers on the freeway, a diminished United States of America where the President is a bit of an afterthought, cyborg pit bulls that are capable of supersonic speeds, and an Aleut with a grudge and a bunch of glass knives. It was a thoroughly enjoyable read, and held my interest until the final page. Recommended for beach reading or commuting.