Catálogo de publicaciones - revistas

<jats:p>Despite intensive laboratory and clinical research over three decades, an effective treatment to delay the onset and progression of Alzheimer’s disease is not at hand. Recent clinical trial failures suggest that we must treat the disease earlier than in its mild to moderate stages, and major progress in validating presymptomatic biomarkers now makes secondary prevention trials possible. We will learn more about the natural history of the disease and any partial therapeutic responses from detailed analyses of recent trial results. This process will likely position the field for success, but only with much greater investment in all aspects of Alzheimer research and with careful design of future trials.</jats:p>

<jats:p>Much of the global burden of disease is associated with behaviors—overeating, smoking, excessive alcohol consumption, and physical inactivity—that people recognize as health-harming and yet continue to engage in, even when undesired consequences emerge. To date, interventions aimed at changing such behaviors have largely encouraged people to reflect on their behaviors. These approaches are often ineffectual, which is in keeping with the observation that much human behavior is automatic, cued by environmental stimuli, resulting in actions that are largely unaccompanied by conscious reflection. We propose that interventions targeting these automatic bases of behaviors may be more effective. We discuss specific interventions and suggest ways to determine whether and how interventions that target automatic processes can enhance global efforts to prevent disease.</jats:p>

<jats:p>Child undernutrition is a major public health challenge, estimated to be responsible for 2.2 million annual deaths. Implementation of available interventions could prevent one-third of these deaths. Emerging evidence suggests that breast-feeding can lead to improvements in intelligence quotient in children and lower risks of noncommunicable diseases in mothers and children decades later. Nonetheless, breast-feeding and complementary feeding practices differ greatly from global recommendations. Although the World Health Organization recommends that infants receive solely breast milk for the first 6 months of life, only about one-third of infants in low-income countries meet this goal, just one-third of children 6 to 24 months old in low-income countries meet the minimum criteria for dietary diversity, and only one in five who are breast-fed receive a minimum acceptable diet. Although the potential effects of improved breast-feeding and complementary feeding appear large, funding for research and greater use of existing effective interventions seems low compared with other life-saving child health interventions.</jats:p>

<jats:p>On top of the unfinished agenda of infectious diseases in low- and middle-income countries, development, industrialization, urbanization, investment, and aging are drivers of an epidemic of noncommunicable diseases (NCDs). Malnutrition and infection in early life increase the risk of chronic NCDs in later life, and in adult life, combinations of major NCDs and infections, such as diabetes and tuberculosis, can interact adversely. Because intervention against either health problem will affect the other, intervening jointly against noncommunicable and infectious diseases, rather than competing for limited funds, is an important policy consideration requiring new thinking and approaches.</jats:p>

<jats:p>Effective prevention of noncommunicable diseases will require changes in how we live, and thereby effect important economic changes across populations, sectors, and countries. What we do not know is which populations, sectors, or countries will be positively or negatively affected by such changes, nor by how much. Without this information we cannot know which policies will produce effects that are beneficial both for economies and for health.</jats:p>

<jats:title>Location, Location, Location</jats:title> <jats:p> It seems obvious that a person's residential neighborhood will influence their sense of well-being, but it has been difficult to nail down cause and effect. <jats:bold> Ludwig <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="1505" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1224648">1505</jats:related-article> ; see the Perspective by <jats:bold> <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6101" page="1464" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1227881">Sampson</jats:related-article> </jats:bold> ) describe the analysis, 10 to 15 years onward, of a large-scale social experiment carried out in five U.S. cities in the mid 1990s. Several thousand residents of poor neighborhoods were given housing vouchers that could only be used if they moved into much less poor neighborhoods. In comparison to a similar group of individuals who did not move, those who did experienced substantial improvement in their subjective well-being. </jats:p>

<jats:title>A Pair of Planets Around a Pair of Stars</jats:title> <jats:p> Most of the planets we know about orbit a single star; however, most of the stars in our galaxy are not single. Based on data from the Kepler space telescope, <jats:bold> Orosz <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="1511" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1228380">1511</jats:related-article> , published online 28 August) report the detection of a pair of planets orbiting a pair of stars. These two planets are the smallest of the known transiting circumbinary planets and have the shortest and longest orbital periods. The outer planet resides in the habitable zone—the “goldilocks” region where the temperatures could allow liquid water to exist. This discovery establishes that, despite the chaotic environment around a close binary star, a system of planets can form and persist. </jats:p>

<jats:title>Keeping Track of Photon Phase</jats:title> <jats:p> In optical interferometers or optical communications, information is often stored in terms of the phase of the waveform or light pulse. However, fluctuations and noise can give rise to random jitter in the phase and amplitude of the optical pulses, making it difficult to keep track of the phase. <jats:bold> Yonezawa <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="1514" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1225258">1514</jats:related-article> ) developed a technique based on quantum mechanical squeezing to determine the phase of randomly varying optical waveforms. The quantum mechanical technique enhanced the precision with which the phase could be determined and, as optical technologies continue to be miniaturized, should be helpful in applications within metrology. </jats:p>

<jats:title>Patterning by Subtraction</jats:title> <jats:p> Soft lithographic patterning is usually a “positive” inking process. A polymer stamp is cured on a hard master substrate and then inked with molecules such as alkane thiols, which can then be transferred to a second substrate (such as gold). However, the resolution of the transferred pattern is often degraded by surface diffusion. <jats:bold> Liao <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="1517" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1221774">1517</jats:related-article> ; see the Perspective by <jats:bold> <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6101" page="1459" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1228493">Rogers</jats:related-article> </jats:bold> ) obtained higher resolution in a subtractive approach, in which oxygen-plasma–activated silicone stamps removed hydroxyl-terminated alkane thiols from gold surfaces. This lift-off process also removed the terminal gold atom bound to the alkane thiol. The bare regions could be backfilled with protein molecules, and multiple lift-off steps could create patterns with features as small as 40 nanometers. </jats:p>

<jats:title>Slip-Sliding Apart</jats:title> <jats:p> One versatile means of synthesizing nanometer-scale cylinders has been to start with ring-shaped molecules that stack on top of each other. <jats:bold> Huang <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="1521" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1224741">1521</jats:related-article> ; see the Perspective by <jats:bold> <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6101" page="1462" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1228178">Zhang and Aida</jats:related-article> </jats:bold> ) took this approach a step further by giving the rings a flexible diameter. Specifically, rings were prepared consisting of six v-shaped building blocks with hydrophobic sides that could slide back and forth along one another and thereby expand or contract the pore at the center. The rings spontaneously stacked to form tubes in dilute aqueous solution, and heating induced contraction of the whole tube in a process that was readily reversible on cooling. </jats:p>