 |
|
|
|||||
Microplasticsthe tiny particles of plastic shed when litter breaks downare everywhere, from the deep sea to Mount Everest, and many researchers worry that they could harm human health. I am a machine learning researcher. With a team of scientists, I have developed a tool to make identification of microplastics using their unique chemical fingerprint more reliable. We hope that this work will help us learn about the types of microplastics floating through the air in our study area, Michigan. Microplasticsa global problem The term plastic refers to a wide variety of artificially created polymers. Polyethylene, or PET, is used for making bottles; polypropylene, or PP, is used in food containers; and polyvinyl chloride, or PVC, is used in pipes and tubes. Microplastics are small plastic particles that range in size from 1 micrometer to 5 millimeters. The width of a human hair, for comparison, ranges from 20 to 200 micrometers. Most scientific studies focus on microplastics in water. However, microplastics are also found in the air. Scientists know much less about microplastics in the atmosphere. When scientists collect samples from the environment to study microplastics, they usually want to know more about the chemical identities of the microplastic particles found in the samples. Fingerprinting microplastics Just as fingerprinting uniquely identifies a person, scientists use spectroscopy to determine the chemical identity of microplastics. In spectroscopy, a substance either absorbs or scatters light, depending on how its molecules vibrate. The absorbed or scattered light creates a unique pattern called the spectrum, which is effectively the substances fingerprint. Just like a forensic analyst can match an unknown fingerprint against a fingerprint database to identify the person, researchers can match the spectrum of an unknown microplastic particle against a database of known spectra. However, forensic analysts can get false matches in fingerprint matching. Similarly, spectral matching against a database isnt foolproof. Many plastic polymers have similar structures, so two different polymers can have similar spectra. This overlap can lead to ambiguity in the identification process. So, an identification method for polymers should provide a measure of uncertainty in its output. That way, the user can know how much to trust the polymer fingerprint match. Unfortunately, current methods dont usually provide an uncertainty measure. Data from microplastic analyses can inform health recommendations and policy decisions, so its important for the people making those calls to know how reliable the analysis is. Conformal prediction Machine learning is one tool researchers have started using for microplastic identification. First, researchers collect a large dataset of spectra whose identities are known. Then, they use this dataset to train a machine learning algorithm that learns to predict a substances chemical identity from its spectrum. Sophisticated algorithms whose inner workings can be opaque make these predictions, so the lack of an uncertainty measure becomes an even greater problem when machine learning is involved. Our recent work addresses this issue by creating a tool with an uncertainty quantification for microplastic identification. We use a machine learning technique called conformal prediction. Conformal prediction is like a wrapper around an existing, already trained machine learning algorithm that adds an uncertainty quantification. It does not require the user of the machine learning algorithm to have any detailed knowledge of the algorithm or its training data. The user just needs to be able to run the prediction algorithm on a new set of spectra. To set up conformal prediction, researchers collect a calibration set containing spectra and their true identities. The calibration set is often much smaller than the training data required for training machine learning algorithms. Usually just a few hundred spectra are enough for calibration. Then, conformal prediction analyzes the discrepancies between the predictions and correct answers in the calibration set. Using this analysis, it adds other plausible identities to the algorithms single output on a particular particles spectrum. Instead of outputting one, possibly incorrect, prediction like this particle is polyethylene, it now outputs a set of predictionsfor example, this particle could be polyethylene or polypropylene. The prediction sets contain the true identity with a level of confidence that users can set themselvessay, 90%. Users can then rerun the conformal prediction with a higher confidencesay, 95%. But the higher the confidence level, the more polymer predictions given by the model in the output. It might seem that a method that outputs a set rather than a single identity isnt as useful. But the size of the set serves as a way to assess uncertaintya small set indicates less uncertainty. On the other hand, if the algorithm predicts that the sample could be many different polymers, theres substantial uncertainty. In this case, you could bring in a human expert to examine the polymer closely. Testing the tool To run our conformal prediction, my team used libraries of microplastic spectra from the Rochman Lab at the University of Toronto as the calibration set. Once calibrated, we collected samples from a parking lot in Brighton, Michigan, obtained ther spectra, and ran them through the algorithm. We also asked an expert to manually label the spectra with the correct polymer identities. We found that conformal prediction did produce sets that included the label the human expert gave it. Microplastics are an emerging concern worldwide. Some places such as California have begun to gather evidence for future legislation to help curb microplastic pollution. Evidence-based science can help researchers and policymakers fully understand the extent of microplastic pollution and the threats it poses to human welfare. Building and openly sharing machine learning-based tools is one way to help make that happen. Ambuj Tewari is a professor of statistics at the University of Michigan. This article is republished from The Conversation under a Creative Commons license. Read the original article.
Category:
E-Commerce
Pretty much everyone will sometimes struggle with anger at work. People fear the wrath of abusive supervisors, suppress anger to maintain a facade of professionalism, or vent anger toward coworkers who are, fairly or not, targets. Reactions to anger in the workplace can be strong, but theyre not always effective. As scholars who also fall prey to the pitfalls of anger ourselves, we are fascinated by anger. We have studied the causes, underlying processes, and consequences of anger from the perspectives of management, psychology, marketing, and negotiations. We recently reviewed more than 400 research articles across psychology, business, and related fields on topics ranging from brain activity to negotiation to race relations. Yet despite the ubiquity of anger in the workplace and the decades of anger research that exists across a number of fields, we found no straightforward way to understand the complexity of the life cycle of anger and how to manage it most effectively. As we dived more deeply into the research literature, though, we realized that simply reframing how we think about anger could provide a novel, flexible framework for how to deal with this emotion in daily life. Our suggestion: Think of anger as a flow of emotion, like water through a garden hose. By thinking of the flow of anger, you can unpack its key dimensions: its path and strength. Understanding whether the hose is pointed effectively and whether the strength of the stream is appropriate are critical for knowing when, how, and why to focus or redirect the anger and amplify or weaken its intensity. The direction of anger Imagine a coworker charges into your office, yelling, breathing heavily, face reddened, veins bulging. Even if you are simply an unsuspecting colleague who happened to have your door open, your attention is undoubtedly now fixed on your coworker. Are you the target of their anger for something you did, or merely an observer of their anger at someone else? If you are an undeserving target, do you try to reframe the issue so that the angry person will realize the anger is better directed elsewhere? If you are the observer, you also have a choice about whether to ignore your coworkers anger or help them redirect it to a more effective outlet. You might simply listen empathetically while they let off steam, perhaps pointing out the relative risks and benefits of their taking their complaints to the supervisor. You are deciding, in effect, what suggestions to make about the direction of this persons anger. The key to effectively managing the direction of anger is to manage the attention of those in the room. Reshaping how angry people attribute blame, for example, can help people take another persons perspective or understand the situation in a new way, directing the flow more productively. The intensity of anger When an angry coworker approaches you as the target, do you ignore the signal or offer to work with the person so a similar situation doesnt happen in the future? Both are ways to tamp down the intensity of the emotion coming at you. When you are angry, do you try to distract yourself from the anger, let it simmer, or embrace it? You are essentially deciding how you want to manage the intensity of your own angry feelings. It is important to recognize that managing the intensity of anger can go in both directions. Sometimes high-intensity anger should be turned down and sometimes subtle anger should be amplified. For example, consider an instance in which you feel anger at what you perceive to be an unfair change to a company policy. In this case, simply going for a walk outside to avoid expressing your frustration may result in the leadership not realizing that you and others on the team feel this way, leaving little opportunity to discuss and update the policy to more reasonable standards. Learning to self-regulate your thoughts and behaviors can help you manage the intensity of any anger you find yourself feeling. Rather than impulsively reacting, you can practice handling your emotions so you control whether you crank up your expressed anger or dial it down. Part of this process is thinking carefully about the cost-benefit trade-offs of expressing your anger. In these ways, you more effectively manage the strength of the flow without unnecessarily just turning it off. Controlling anger Knowing when, how, and why to shape the direction and intensity of anger is no small feat. Some of this decision is rightly based on the situation. For example, is it safe to step in? Do you feel personally skilled at intervening? But it is within everyones power to learn how to manage their own and others anger more effectively. To do so, you need to understand your role and whether the flow is a onetime situation or a persistent problem. Understanding whether youre holding the hose, standing in its path, or observing from a distance is the first step to effectively managing the direction and intensity of the flow. Second is deciding whether and how to intervene: Can you reframe the initial trigger so that the faucet is never turned on, or turned on more or less powerfully? If anger is already too strong and you cannot or do not want to avoid it, can you help the angry person regulate the direction and intensity of their anger to overcome the issue in some way? You can get better at controlling the flow of anger in ways that can improve rather than harm relationships and outcomes. Research supports working on your emotional intelligence and building belief in your own capability to handle anger. Manage factors that tend to wrest control of the hose away from you, including becoming defensive, feeling shame, or even suffering from a lack of sleep. Taking these steps and practicing controlling the hoses path and intensity can help address problems in the short term and prevent anger from becoming a destructive pattern in the long term. Laura Rees is an associate professor of organizational behavior at Oregon State University. Ray Friedman is a professor of management and professor of Asian studies at Vanderbilt University. This article is republished from The Conversation under a Creative Commons license. Read the original article.
Category:
E-Commerce
Julian Baggini is a philosopher with a long and deep interest in food and where it comes from. His books include internationally bestselling How the World Thinks; How to Think Like a Philosopher; The Virtues of the Table; and The Pig That Wants to be Eaten. He is the Academic Director of the Royal Institute of Philosophy and a member of the Food Ethics Council. He is a regular columnist for The Guardian, Prospect magazine, Financial Times, and The Wall Street Journal. Whats the big idea? Food is such a big topic that few really grasp the whole of it. Using his philosophical skillset, Julian sketches a picture of how all the elements of food consumption and production fit together. Extracted from the complexity of foods impact on health, economy, wellbeing, nature, civil strife, and so on, there are common principles that characterize food systems that work for us and for the planet. Below, Julian shares five key insights from his new book, How the World Eats: A Global Food Philosophy. Listen to the audio versionread by Julian himselfin the Next Big Idea App. 1. Debate about food and farming is too polarized Polarized debate about food and farming stands in the way of everyone coming together for the common good. Beneath the dichotomous rhetoric, the world is not nearly as divided as it seems. Take the apparent chasm between organic and non-organic agriculture. In one way, it is a sharp divide because you either tick the boxes and get certified organic or you dont. But in practice, the difference between the two camps is blurry. Some farms are in effect organic but cant say they are because they dont pay for certification. Nor can we separate them out based on which use fertilizers and pesticides and which dont. Organic farms use both, only they cant be syntheticin their definition of the term. But so-called natural inputs are not necessarily safer. Copper is allowed under the terms of certification as an organic fungicide (commonly used for tomato production), but copper is known to be toxic to humans. Some non-organic farms use chemical inputs with such care and in such limited amounts that they pose no threat to human health or wildlife. Or take the distinction between farmed and wild-caught fish. Whether one is better than the other all depends. There are some terrible practices on the open seas, including the use of huge trawlers to scrape the seabed, basically bulldozing habitats. There are also awful fish farms that pollute surrounding waters and nurture sick fish. But there are also good practices on both sides. Like most either/or questions about food, farmed or wild? is just the wrong question. Simplistic, polarized thinking has real consequences. Take the idea that plastic is bad and biodegradable packaging is good. An extra layer of plastic wrap in the packaging of Danish cold meats increases their shelf life and reduces waste, and for almost all food, the environmental impact of waste is higher than that of the packaging that prevents it. Or take the owner of a vegetable box delivery scheme who knows that the greenest option is to use reusable and recyclable hard plastic boxes but must use cardboard because his customer base is so convinced that plastic is always the enemy. 2. Plurality is key to how we feed ourselves There is no one right way to farm, make food, or eat. It depends on context, culture, and circumstance. Grazing cattle is sustainable and efficient on the Argentinian Pampas, but not so easily done at scale on the polders of the Netherlands. The Mediterranean diet may be very healthy, but the Japanese one is at least as good. There is a place for small artisan producers, but the big manufacturers of, say, pasta do a good job supplying reliable, tasty, nutritious food at a good price. What works on a wheat farm in one place may not work in another in the next valley, let alone in another country. Advocates of land sharing argue that farmland must be made more hospitable to wildlife so that we can share our productive land with nature. Land sparers argue that the best way to protect the environment is to make agriculture as efficient as possible so that it uses less land, leaving other habitats pristine. Both perspectives are right, and both are wrong. In some places, land sharing works best, while in others, land sparing is more appropriate. The right option in one place can be wrong elsewhere. Too often, people advocate for one-size-fits-all solutions: that the world needs to go organic, or that everyone should be using more synthetic inputs; that we should all go vegan; that we should bring down the big food and agri-businesses; that everything we eat should be prepared from fresh. We homo sapiens have been able to feed ourselves for millennia because we have been resourceful, adapting ourselves to variable and changing conditions. Plurality has been one of our greatest strengths, and we should continue to encourage and celebrate it. 3. The ground rules of nutrition are simple because it is so complicated It is hubris to think we can micro-manage our diets to make significant differences to our health and longevity. The focus should be on the big, obvious elements of a good diet. It is still difficult to beat Michael Pollans famous seven-word maxim: eat food, not too much, mostly plants. By foods, he, of course, means real, whole foods and not highly processed edible food-like substances, to use his memorable phrase. We keep getting seduced by hucksters and misguided diet guides who promise the ultimate health hacks. Right now, the big noise is about the gut microbiome, with many making millions by selling prebiotics and probiotics, gut shots, and the like. But the Hadza hunter-gatherers of Tanzania have a really healthy gut microbiome, and they dont eat anything like kimchi or kefir, let alone manufactured so-called gut-boosters. They only eat what they have gathered that day. Their guts are healthy because they eat a wide range of fibrous plants. The idea that we should focus on big factors gives us the license to relax a little. What matters is your dietary pattern, not any individual food you eat. If your diet is based on healthy foods, it doesnt matter if you have the odd twinkie or a triple-cheese pizza. There is a lot of justifiable concern about ultra-processed foods, but they are not poisonous in small doses. Purity in eating is seductive but unnecessary. Many of us have individual needs that demand more specific dietary advice. We have intolerances, allergies, or health conditions that can be triggered by certain foods. But unless you have a specific medical reason to avoid some foods and have more of others, you should stop worrying and eat a good variety of proper foods. 4. Around the world, there are huge injustices in the food system Cocoa farmers who earn less every day than it costs someone to buy a single bar of chocolate made from their beans; migrant workers exploited as farm laborers, sometimes not being paid at all; modern slavery, not just in economically developing nations but unde the noses of consumers in industrialized countries too; livestock kept in atrocious conditions, just so that we can enjoy cheap chicken, burgers, and sausages. We all know this, even if we choose to look away. These are not bugs in the food system; they are features of it. Our entire supply chain has been designed or evolved to make food as cheap for consumers as possible. However, it can only do this if humans and animals in the supply chain are exploited. This needs to change, even if it isnt easy. We have become so reliant on inexpensive food that when prices increased a few years ago, many people found they could no longer afford to eat. This is true even though, by historical standards, households were still spending a smaller portion of their income on food than at nearly any other time in history. Some say food cannot become more expensive because the poor can barely afford it now. But the solution to poverty is not to make food so cheap that even the poor can afford it. The solution is to ensure that even the poorest have enough money to feed themselves properly. Nor should it be verboten to consider food subsidies. After all, many countries, including the USA, already spend billions subsidizing agriculture and other industries. 5. There are seven principles for a humane, sustainable, nutritious food system If you were to skip to the end of my book and read these seven principles, you might think they sound obvious. That is what makes them so powerful. Everyone agrees with them, but hardly anyone is acting in accordance with them. Not only do we almost all agree about what a better food system should look like, but we also know most of what it will take to make it a reality. There are numerous levers we could pull. We could have much higher standards of animal welfare. The power of large businesses to shape the food world in their own interests rather than in those of humankind could be curbed. The costs placed on society and future generations of the food system could be properly measured and either paid for or not allowed to occur in the first place. Every country could have a proper land use framework to achieve the right balance between agricultural productivity, conservation, and regeneration. Our diets can shift away from highly processed foods toward ones based on whole foods. Farmers and farm laborers could receive a much fairer share of the price paid by consumers. Every citizen has the potential not only to have a voice in how the food world is shaped, but real power in using that voice. Too many calls for change are utopian, requiring a wholesale shift of values that is not going to happen. Fortunately, we do not need to tear the whole system down and start again. Positive change depends on people recognizing that the values we already hold are discordant with our food system. Values and practices can be brought into harmony by a series of adjustments, some radical, but all ad hoc and doable. The will for change and the possibility for change can converge, join forces, and transform how the world eats for the better. This article originally appeared in Next Big Idea Club magazine and is reprinted with permission.
Category:
E-Commerce
All news |
||||||||||||||||||
|
||||||||||||||||||