2015 11 Nov Vol 313 N 5

SCIENTIFIC AMERICAN\nNOVEMBER 2016\nMaster Builders\nThey didn't just move stone.\nThey also were part\nof a social network\nthat changed\nthe world. SCIENTIFIC AMERICAN\nNOVEMBER 2015\nVOLUME 313, NUMBER 5\n\nARCHAEOLOGY\n32 The Pyramid Effect\nThe workers who built Egypt's\nmost famous structures did not\njust drag stone blocks. They were\nhighly organized, elite labor force\nthat used extensive trade networks\nto acquire building supplies.\nBy Zack Zorich\n\nCOSMOLOGY\n40 Seeing in the Dark\nAn extraordinary camera that\ncan map 200 million galaxies\nwill help astronomers in the\nEnergy Survey explain\nwhy the universe seems to be\nexpanding at an ever faster pace.\nBy Joshua Frieman\n\nMEDICINE\n48 Disease Detector\nTiny new devices promise to\ndiagnose infectious diseases\nwithin minutes instead of days—\neven as they struggle to win the\npublic’s trust in the process.\nBy Shanna O. Kelley\n\nAGRICULTURE\n52 The Battle of Olives\nAs a nasty bacterium threatens\nItaly’s olive groves, growers\nand scientists fight about\nwhat to do.\nBy Barbl Latané Nadreau\n\nTECHNOLOGY\n60 Robots with Heart\nBefore we start sharing our lives\nwith robots, we must teach\nthem to understand and mimic\nhuman emotion.\nBy Pascale Fung\n\nCHILD DEVELOPMENT\n64 Baby Talk\nAn infant is a natural-born\nlinguist capable of mastering\nany language.\nBy Patricia K. Kuhl\n\nPHYSICS\n70 Where Is Here?\nOur sense of the universe as\nan orderly expanse where\nevents happen in absolute\nlocations is an illusion.\nBy George Musser SCIENTIFIC AMERICAN\n\n6 From the Editor\n8 Letters\n12 Science Agenda\nSuperpowers: Stop dodging a pact to keep weapons\nout of space. By the Editors\n\n17 Advances\nHow similar are mild cove disease and Alzheimer’s?\nThe rise of fake marijuana. Black hole births witnessed.\n\n24 The Science of Health\nMany children diagnosed with food allergies turn out\nnot to have them after all. By Ellen Ruppel Shell\n\n30 TechnoFiles\nRelax. Cybercriminals are not about to take control\nof your car. By Daniel Pogue\n\n74 Recommended\nAmazing infographics. Did dark matter kill the dinosaurs?\nWhy we believe conspiracy theories. A doctor’s reflections\non prejudice in medicine. By Clara Moskowitz\n\n75 Skeptic\nDo we perceive reality as it is? By Michael Shermer\n\n76 Anti Gravity\nChimp with willow makes flying drone weep.\nBy Steve Mirsky\n\n79 50, 100 & 150 Years Ago\n\n80 Graphic Science\nInvasive species are spreading primarily from the\nNorthern Hemisphere south.\n\nSustainable Development\nScientific American provides perspective, context\nand criticism of the United Nations’ recently adopted\nSustainable Development Goals.\nGo to www.ScientificAmerican.com/how2015/sustainability A Risky Arms Race in Space\nSuperpowers are flexing military muscles in orbit, but the U.S. can lead the world away from a planetary disaster\nby the Editors\nOn January 11, 2007, with no warning, China's military fired a ballistic missile at one of the country's weather satellites and blew it to bits. China's first test of an anti satellite weapon made a mess; it tossed thousands of metal shards into lower low-Earth orbit, where the International Space Station, other crewed missions and about half of all operational satellites fly.\nOther superpowers have been exploring space-based weaponry. In October 2014 the U.S. Air Force's X-37B Orbital Test Vehicle was testing technologies for hypersonic missiles—weapons capable of hitting any target on Earth within an hour—and possibly techniques for repairing or disabling satellites. Russia has tested three satellites in recent years that may be able to intercept other orbiting spacecraft or code-snap or physically subvert them.\nThe end result of these actions is a dangerous situation in which debris from our planet could knock out global communications, vital satellites and astronauts on the ground. World powers need to act now to de—emphasize a demilitarized zone about space.\nIn 2008 China and Russia made a motion in that direction by proposing a United Nations treaty that would ban weapons in space. But the draft contains no verification provisions and makes no mention of the kind of Earth-based satellite-killing technology China has been testing. It has been a nonstarter for the U.S. not only because of its loopholes but also because Congress is deeply hostile to any treaty that places limits on the American military.\nThis proposal, joined by that of other bulkhead countries, dooms any U.N. treaty, which would require unanimous approval from all members of the conference in which it is introduced.\nThis year a more feasible alternative proposed by the European Union was discussed: a disarmament process backed by a nonbinding International Code of Conduct for Outer Space Activities calls on countries to maintain the area around our planet as a peaceful global commons, and it sets out practical guidelines for avoiding collisions in space and for minimizing and removing debris. Michael Krepon, co-founder of the Stimson Center, a global peace and security think tank, explains that the code of conduct is modeled on cold war measures such as the Incidents at Sea Agreement between the U.S. and the Soviet Union, which in 1972 established rules for military forces operating in close proximity. Another U.S.-Soviet Union pact, signed in 1989, set expectations for troops using radar range finders, as well as radio channels that could jam other frequencies, actions that could easily be interpreted as hostile.\nThere were no binding treaties, but the U.S. and the Soviet Union monitored them, and they helped to prevent disaster. This time, however, Russia, China and several other nations have said they will not abide by the proposed space code because they were left out of the drafting process, and they object to some of the codes provisions. The E.U. should adopt the International Code of Conduct for Outer Space Activities anyway, and the U.S. should join them at the launch. The history of other weapons agreements suggests other nations—perhaps eventually even China and Russia—will follow out of self-interest. Nobody wants its satellites destroyed, and in the absence of a treaty, standardization of navigation equipment is just about the only way to achieve that goal. Even the greatest superpower's satellites are easy targets for a motivated attacker, so the best defense is for everyone to agree not to shoot.\nGiven the alternatives—placing all chips on the vanishingly small possibility of a binding U.N. treaty or coding nothing and hoping for the best—an international code of conduct looks like the best strategy. The Obama administration, Europe and their allies should be ready to push and partner by these standards as soon as possible. International norms have prevented catastrophe before, and they can do it again. Racial Bias in Medicine\nTo tackle it, doctors need to think hard about what it means to be \"objective\"\nby Rachel Pearson\nMedicine has a race problem. Doctors consistently provide worse care to people of color, particularly African-Americans and Latinos. In studies that control for socioeconomic status and access to care, researchers have found racial disparities in the quality of care across a wide range of diseases: asthma, heart attack, diabetes, and prenatal care, to name a few. Two studies performed in emergency rooms showed that doctors were far more likely to fail to order pain medication for black and Hispanic patients who came in with bone fractures. Doctors are less likely to diagnose black patients with depression/psychosis disorders such as schizophrenia. Hispanic HIV patients are likelier to die than white HIV patients, and black HIV patients are less likely to get antibiotics to prevent pneumonia. There’s, however, one procedure that doctors are more likely to perform on black patients: amputation.\nAs a medical humanities M.D., Ph.D. student, I set out to understand how my profession, which prides itself on objectivity, could be influenced by something so subjective and harmful as racial bias. I found part of the answer in the kind of objectivity that doctors value. As trainees, we aspire to be like scientists, who see the self as a potential source of error and therefore try to suppress it. But medicine is not a science—it is a moral practice that uses science. When problematic parts of ourselves, such as racial bias, intrude, we find it hard to recognize the problem.\nIn studying memories of medical students and residents, I found that many trainees feel an acute anxiety about the self. When we react emotionally to intense situations, we worry that we are not being good doctors. When we do not react—when we coolly watch a patient die or approach a critically ill child with clinical detachment—we worry that we are becoming monsters. We are unsure of the role emotions should play in clinical care. Interestingly, our specific emotion—discomfort—tends to trigger thoughts about disparities in care. Feeling uncomfortable, we may do a better job of encountering patients of other races.\nI was surprised to find that white trainees rarely mentioned race in their memories, even though they are more likely to care for patients of color in the free clinics and public hospitals where we learn. In medical school, we come to treat race as a biological fact; something that provides certain patients access to certain diseases. Medical students and residents of color perceive race differently—as a social experience. One surgeon, general Joycelyn Elders recounts being barred from the cafeteria when she was in medical school, and in her memoirs, she recalls being invited to dinner with a white professor who chastised her for not being a “classic” student. Navajo surgeon Lori Arviso Alvardo shares how to build students of color into a mentor-mentee network. Students of color also report feeling stigmatized by their own experiences of prejudice to provide decent care to patients of color.\nIf white medical trainees and talking heads treat race not as a biological fact, how even respected black faculty might begin by revising our model of objectivity. Doctors are always themselves—emotional, particular and sometimes biased—in the hospital. We should accept this fact and learn to work with it. We should remind ourselves, forewarned, to notice our discomfort and respond by slowing down instead of rushing out of patient encounters. (Some medical schools are now training students to do just that.)\nOther commonsense measures to tackle bias can include aggressively recruiting and retaining medical students who reflect the diversity of the nation, explicitly training physicians to recognize unconscious bias and fairly promoting physicians of color within academic medicine. Ultimately, I hope that revising our understanding of objectivity in medicine can be—a tool for ensuring that all people’s lives are cherished. If doctors begin to earn our authority as science-using moral leaders, then both medicine and society have much to gain. The Great Brain Drain\nIs a chain reaction of toxic proteins behind all neurodegenerative diseases?\nIn the human form of mad cow disease, called Creutzfeldt-Jakob, a person's brain deteriorates—literally developing holes that cause rapidly progressing dementia. The condition is fatal within one year in 90 percent of cases. The culprits behind the disease are prions—misfolded proteins that can induce normal proteins around them to take misfolded and accumulate. Scientists have known that these self-propagating, pathological proteins cause some rare brain disorders, such as kuru in Papua New Guinea. But growing evidence suggests that prions are at play in many, if not all, neurodegenerative disorders, including Alzheimer’s, Huntington’s and Parkinson’s, also marked by aggregations of malformed proteins.\nUntil recently, there was no evidence that the abnormal proteins found in people who suffer from these well-known diseases could be transmitted directly from person to person. The tenor of that discussion suddenly changed this September when newly published research in ADVANCES\n\nthe journal Nature provided the first hint \nsuch human-to-human transmission may \nbe possible (Scientific American is part of \nSpringer Nature). \n\nFor the study, John Collinge, a neuro- \nlogist at University College London, and \nhis colleagues conducted autopsies on \neight patients who died between the \nages of 39 and 63 from Creutzfeldt-Jakob. \nAll the subjects had acquired the disease \nafter treatment with growth hormone \nthat had been contaminated with \nprion infectivity. The link became clearer when the \nresearchers discovered that six of the \nbrains also bore telltale signs of Alzheim- \ner’s—in the form of clumps of Abeta- \npeptide, diagnostic for the disease, \neven though the patients should have \nbeen too young to exhibit such symptoms. \n\nThese observations suggest that there is \na mechanism for transmission of disease \nfrom one person to another. Yet human \ntransmission of prion disease has \nremained poorly understood, and there is \na clear need for more rigorous research \ninto the latent periods and contexts in which \nsuch transmission occurs. \n\nThe new finding is provocative, but \nexperts advise caution in interpreting \nthe results. For instance, neuroscientist \nJohn Trojanowski of the University of \nPennsylvania points to the small size of \nthe study and lack of evidence for \ntransmission in support of causality. But \nif it is eventually shown that Alzheimer’s \nand other neurodegenerative diseases \nindeed share the same pathological \npathway and mechanism, treatments \ncould target one and all. \n\n\"Transmission may occur in only a \nsmall percentage of human cases,\" says \nClaudio Soto, a professor of neurology \nat the University of Texas Health Science \nCenter in Houston. \"But the underlying \nmessage is that this is a very interesting \nthing that could lead to new opportunities for ther- \napeutic interventions and diagnostics.\" \n\nInvestigators such as Soto and Collinge \nare working on ways to detect in body fluids the presence of small clumps of the \ntransmissible proteins now thought to be \ninvolved in Alzheimer’s and other neuro- \ndegenerative diseases, which could represent a diagnostic advance.\n\nSuch detection will likely be difficult. \nA study published online in September \nin the journal Nature Neuroscience by \nMatthias Jucker of the University of \nTübingen in Germany and his colleagues \nexamined extremely sensitive forms of beta-amyloid \nproteins, referred to as protofibrils. \nThese proteins seem to acquire certain \npathological properties even after \neight months of living in the test tubes. \n\"These proteins likely profile falling might hinder \ntheir eventual access to binding and signaling \nreceptors, quickening reiterative symptoms \ndett extenuating route to lug. \n\nOne potential prionlike protein \nthat has piqued interest is beta-amyloid \nprotein because initially Christopher \nKinsley induced this substance with substances \nbelieved caused by coming off unknown toxin \nsuch as misfolded protein \nin Parkinson’s—can cause a \nsimilar but rarer neurodegenerative \nunderpinning consuming floods of misfolded \nproteins. \nUnderstanding how variants differ in \npathogenicity and how the particular configuration \ninfluences their pathogenic nature is \ndestined to become a focus of future \ninvestigation. \"There's evidence that both \nprion and beta-amyloid exist as differ- \nent strains and may be very different biolog- \nical effects,\" says Larry C. Walker of \nMonash University, who was involved in \nthe Nature Neuroscience study. \"In this \nunderstanding this will give us insight \ninto what happens in disease.\" \n\nAs the evidence increases, more sci- \nentists now suspect that prionlike pro- \nteins probably underlie all neurodegen- \nerative disorders. Prusiner expected the \ncurrent craze in thinking; in his 1997 \nNobel Prize lecture, he predicted that \nthe understanding of prion formation \ncould \"open new approaches to decode- \nr the causes of and to developing \neffective therapies for the more common \nneurodegenerative diseases, including \nAlzheimer’s disease, Parkinson’s disease, \nand amyotrophic lateral sclerosis (ALS).\" \n\n—Diana Kwon \n\nBY THE NUMBERS\n\n3.4 \nmillimeters \nAverage sea-level rise \nin the Chesapeake Bay region \nper year (twice that of \nthe global average). \n\n1.3–1.7 \nmillimeters \nAnnual subsidence of the area.\n\n15 \ncentimeters \nTotal depth by which D.C. \ncould sink by 2100. \n\n\n\n\n\n\n\n18 Scientific American, November 2015