journal
MENU ▼
Read by QxMD icon Read
search

Science

journal
https://www.readbyqxmd.com/read/28438989/documenting-decline-in-u-s-economic-mobility
#1
Lawrence F Katz, Alan B Krueger
Median incomes stagnate as inequality increases.
April 24, 2017: Science
https://www.readbyqxmd.com/read/28438988/the-fading-american-dream-trends-in-absolute-income-mobility-since-1940
#2
Raj Chetty, David Grusky, Maximilian Hell, Nathaniel Hendren, Robert Manduca, Jimmy Narang
We estimated rates of "absolute income mobility"-the fraction of children who earn more than their parents-by combining data from U.S. Census and Current Population Survey cross sections with panel data from de-identified tax records. We found that rates of absolute mobility have fallen from approximately 90% for children born in 1940 to 50% for children born in the 1980s. Increasing GDP growth rates alone cannot restore absolute mobility to the rates experienced by children born in the 1940s. However, distributing current GDP growth more equally across income groups as in the 1940 birth cohort would reverse more than 70% of the decline in mobility...
April 24, 2017: Science
https://www.readbyqxmd.com/read/28428318/bottom-up-construction-of-a-superstructure-in-a-porous-uranium-organic-crystal
#3
Peng Li, Nicolaas A Vermeulen, Christos D Malliakas, Diego A Gómez-Gualdrón, Ashlee J Howarth, B Layla Mehdi, Alice Dohnalkova, Nigel D Browning, Michael O'Keeffe, Omar K Farha
Bottom-up construction of highly intricate structures from simple building blocks remains one of the most difficult challenges in chemistry. Here, we report a structurally complex, mesoporous uranium-based metal-organic framework (MOF) made from simple starting components. The structure is comprised of 10 uranium nodes and 7 tricarboxylate ligands (both crystallographically non-equivalent); resulting in a 173.3 angstrom cubic unit cell enclosing 816 uranium nodes and 816 organic linkers-the largest unit cell found for any nonbiological material...
April 20, 2017: Science
https://www.readbyqxmd.com/read/28408723/nucleic-acid-detection-with-crispr-cas13a-c2c2
#4
Jonathan S Gootenberg, Omar O Abudayyeh, Jeong Wook Lee, Patrick Essletzbichler, Aaron J Dy, Julia Joung, Vanessa Verdine, Nina Donghia, Nichole M Daringer, Catherine A Freije, Cameron Myhrvold, Roby P Bhattacharyya, Jonathan Livny, Aviv Regev, Eugene V Koonin, Deborah T Hung, Pardis C Sabeti, James J Collins, Feng Zhang
Rapid, inexpensive, and sensitive nucleic acid detection may aid point-of-care pathogen detection, genotyping, and disease monitoring. The RNA-guided, RNA-targeting CRISPR effector Cas13a (previously known as C2c2) exhibits a "collateral effect" of promiscuous RNAse activity upon target recognition. We combine the collateral effect of Cas13a with isothermal amplification to establish a CRISPR-based diagnostic (CRISPR-Dx), providing rapid DNA or RNA detection with attomolar sensitivity and single-base mismatch specificity...
April 13, 2017: Science
https://www.readbyqxmd.com/read/28408722/ephrin-b1-mediated-repulsion-and-signaling-control-germinal-center-t-cell-territoriality-and-function
#5
Peiwen Lu, Changming Shih, Hai Qi
Follicular T-helper (TFH) cells orchestrate the germinal center (GC) reaction locally. Local mechanisms regulating their dynamics and helper functions are not well defined. Here we found that GC-expressed Ephrin B1 (EFNB1) repulsively inhibited T cell to B cell adhesion and GC TFH retention by signaling through TFH-expressed EPHB6 receptor. At the same time, EFNB1 promoted IL-21 production from GC TFH cells by signaling predominantly through EPHB4. Consequently, EFNB1-null GCs were associated with defective production of plasma cells despite harboring excessive TFH cells...
April 13, 2017: Science
https://www.readbyqxmd.com/read/28408721/decarboxylative-borylation
#6
Chao Li, Jie Wang, Lisa M Barton, Shan Yu, Maoqun Tian, David S Peters, Manoj Kumar, Anthony W Yu, Kristen A Johnson, Arnab K Chatterjee, Ming Yan, Phil S Baran
The widespread use of alkyl boronic acids and esters is frequently hampered by the challenges associated with their preparation. Herein we describe a simple and practical method to rapidly access densely functionalized alkyl boronate esters from abundant carboxylic substituents. This broad-scope Ni-catalyzed reaction uses the same activating principle as amide bond formation to replace a carboxylic acid with a boronate ester. Application to peptides allowed expedient preparations of α-amino boronic acids, often with high stereoselectivity, facilitating the synthesis of both FDA approved alkyl boronic acid drugs (Velcade and Ninlaro) as well as a boronic acid version of the iconic antibiotic vancomycin...
April 13, 2017: Science
https://www.readbyqxmd.com/read/28386027/self-organized-notch-dynamics-generate-stereotyped-sensory-organ-patterns-in-drosophila
#7
Francis Corson, Lydie Couturier, Hervé Rouault, Khalil Mazouni, François Schweisguth
The emergence of spatial patterns in developing multicellular organisms relies on positional cues and cell-cell communication. Drosophila sensory organs have informed a paradigm where these operate in two distinct steps: prepattern factors drive localized proneural activity, then Notch-mediated lateral inhibition singles out neural precursors. Here we show that self-organization through Notch signaling also organizes the proneural stripes that resolve into rows of sensory bristles on the fly thorax. Patterning, initiated by a gradient of Delta ligand expression, progresses through inhibitory signaling between and within stripes...
April 6, 2017: Science
https://www.readbyqxmd.com/read/28386026/coupling-between-distant-biofilms-and-emergence-of-nutrient-time-sharing
#8
Jintao Liu, Rosa Martinez-Corral, Arthur Prindle, Dong-Yeon D Lee, Joseph Larkin, Marçal Gabalda-Sagarra, Jordi Garcia-Ojalvo, Gürol M Süel
Bacteria within communities can interact to organize their behavior. It remains unclear whether such interactions extend beyond a single community to coordinate the behavior of distant populations. We discovered that two Bacillus subtilis biofilm communities undergoing metabolic oscillations become coupled through electrical signaling and synchronize their growth dynamics. Coupling increases competition by also synchronizing demand for limited nutrients. As predicted by mathematical modeling, we confirm that biofilms resolve this conflict by switching from in-phase to anti-phase oscillations...
April 6, 2017: Science
https://www.readbyqxmd.com/read/28386025/greater-role-for-atlantic-inflows-on-sea-ice-loss-in-the-eurasian-basin-of-the-arctic-ocean
#9
Igor V Polyakov, Andrey V Pnyushkov, Matthew B Alkire, Igor M Ashik, Till M Baumann, Eddy C Carmack, Ilona Goszczko, John Guthrie, Vladimir V Ivanov, Torsten Kanzow, Richard Krishfield, Ronald Kwok, Arild Sundfjord, James Morison, Robert Rember, Alexander Yulin
Arctic sea-ice loss is a leading indicator of climate change and can be attributed, in large part, to atmospheric forcing. Here, we show that recent ice reductions, weakening of the halocline, and shoaling of intermediate-depth Atlantic Water layer in the eastern Eurasian Basin have increased winter ventilation in the ocean interior, making this region structurally similar to that of the western Eurasian Basin. The associated enhanced release of oceanic heat has reduced winter sea-ice formation at a rate now comparable to losses from atmospheric thermodynamic forcing, thus explaining the recent reduction in sea-ice cover in the eastern Eurasian Basin...
April 6, 2017: Science
https://www.readbyqxmd.com/read/28360137/the-applied-value-of-public-investments-in-biomedical-research
#10
Danielle Li, Pierre Azoulay, Bhaven N Sampat
Scientists and policy-makers have long argued that public investments in science have practical applications. Using data on patents linked to U.S. National Institutes of Health (NIH) grants over a 27-year period, we provide a large-scale accounting of linkages between public research investments and subsequent patenting. We find that about 10% of NIH grants generate a patent directly but 30% generate articles that are subsequently cited by patents. Although policy-makers often focus on direct patenting by academic scientists, the bulk of the effect of NIH research on patenting appears to be indirect...
March 30, 2017: Science
https://www.readbyqxmd.com/read/28360136/high-performance-light-emitting-diodes-based-on-carbene-metal-amides
#11
Dawei Di, Alexander S Romanov, Le Yang, Johannes M Richter, Jasmine P H Rivett, Saul Jones, Tudor H Thomas, Mojtaba Abdi Jalebi, Richard H Friend, Mikko Linnolahti, Manfred Bochmann, Dan Credgington
Organic LEDs promise highly efficient lighting and display technologies. We introduce a new class of linear donor-bridge-acceptor light-emitting molecules, which enable solution-processed LEDs with near-100% internal quantum efficiency at high brightness. Key to this performance is their rapid and efficient utilization of triplet states. Using time-resolved spectroscopy, we establish that luminescence via triplets occurs within 350 ns at ambient temperature, after reverse intersystem crossing to singlets. We find that molecular geometries exist at which the singlet-triplet energy gap (exchange energy) is close to zero, such that rapid interconversion is possible...
March 30, 2017: Science
https://www.readbyqxmd.com/read/28360134/colloidally-prepared-la-doped-basno3-electrodes-for-efficient-photostable-perovskite-solar-cells
#12
Seong Sik Shin, Eun Joo Yeom, Woon Seok Yang, Seyoon Hur, Min Gyu Kim, Jino Im, Jangwon Seo, Jun Hong Noh, Sang Il Seok
Perovskite solar cells (PSCs) exceeding a power conversion efficiency (PCE) of 20% have mainly been demonstrated by using mesoporous titanium dioxide (mp-TiO2) as an electron-transporting layer. However, TiO2 can reduce the stability of PSCs under illumination (including ultraviolet light). Lanthanum (La)-doped BaSnO3 (LBSO) perovskite would be an ideal replacement given its electron mobility and electronic structure, but LBSO cannot be synthesized as well-dispersible fine particles or crystallized below 500°C...
March 30, 2017: Science
https://www.readbyqxmd.com/read/28336563/complex-multifault-rupture-during-the-2016-mw-7-8-kaik%C3%A5-ura-earthquake-new-zealand
#13
Ian J Hamling, Sigrun Hreinsdóttir, Kate Clark, John Elliott, Cunren Liang, Eric Fielding, Nicola Litchfield, Pilar Villamor, Laura Wallace, Tim J Wright, Elisabetta D'Anastasio, Stephen Bannister, David Burbidge, Paul Denys, Paula Gentle, Jamie Howarth, Christof Mueller, Neville Palmer, Chris Pearson, William Power, Philip Barnes, David J A Barrell, Russ Van Dissen, Robert Langridge, Tim Little, Andrew Nicol, Jarg Pettinga, Julie Rowland, Mark Stirling
On 14th November 2016, the northeastern South Island of New Zealand was struck by a major Mw 7.8 earthquake. Field observations, in conjunction with InSAR, GPS, and seismology reveal this to be one of the most complex earthquakes ever recorded. The rupture propagated northward for more than 170 km along both mapped and unmapped faults, before continuing offshore at its northeastern extent. Geodetic and field observations reveal surface ruptures along at least 12 major faults, including possible slip along the southern Hikurangi subduction interface, extensive uplift along much of the coastline and widespread anelastic deformation including the ~8 m uplift of a fault-bounded block...
March 23, 2017: Science
https://www.readbyqxmd.com/read/28336562/de-novo-assembly-of-the-aedes-aegypti-genome-using-hi-c-yields-chromosome-length-scaffolds
#14
Olga Dudchenko, Sanjit S Batra, Arina D Omer, Sarah K Nyquist, Marie Hoeger, Neva C Durand, Muhammad S Shamim, Ido Machol, Eric S Lander, Aviva Presser Aiden, Erez Lieberman Aiden
The Zika outbreak, spread by the Aedes aegypti mosquito, highlights the need to create high-quality assemblies of large genomes in a rapid and cost-effective fashion. Here, we combine Hi-C data with existing draft assemblies to generate chromosome-length scaffolds. We validate this method by assembling a human genome, de novo, from short reads alone (67X coverage). We then combine our method with draft sequences to create genome assemblies of the mosquito disease vectors Aedes aegypti and Culex quinquefasciatus, each consisting of three scaffolds corresponding to the three chromosomes in each species...
March 23, 2017: Science
https://www.readbyqxmd.com/read/28325842/surface-changes-on-comet-67p-churyumov-gerasimenko-suggest-a-more-active-past
#15
M Ramy El-Maarry, O Groussin, N Thomas, M Pajola, A-T Auger, B Davidsson, X Hu, S F Hviid, J Knollenberg, C Güttler, C Tubiana, S Fornasier, C Feller, P Hasselmann, J-B Vincent, H Sierks, C Barbieri, P Lamy, R Rodrigo, D Koschny, H U Keller, H Rickman, M F A'Hearn, M A Barucci, J-L Bertaux, I Bertini, S Besse, D Bodewits, G Cremonese, V Da Deppo, S Debei, M De Cecco, J Deller, J D P Deshapriya, M Fulle, P J Gutierrez, M Hofmann, W-H Ip, L Jorda, G Kovacs, J-R Kramm, E Kührt, M Küppers, L M Lara, M Lazzarin, Z-Yi Lin, J J Lopez Moreno, S Marchi, F Marzari, S Mottola, G Naletto, N Oklay, A Pommerol, F Preusker, F Scholten, X Shi
The Rosetta spacecraft spent ~2 years orbiting comet 67P/Churyumov-Gerasimenko, most of it at distances that allowed surface characterization and monitoring at submeter scales. From December 2014 to June 2016, numerous localized changes were observed, which we attribute to cometary-specific weathering, erosion, and transient events driven by exposure to sunlight and other processes. While the localized changes suggest compositional or physical heterogeneity, their scale has not resulted in substantial alterations to the comet's landscape...
March 21, 2017: Science
https://www.readbyqxmd.com/read/28302793/anticancer-sulfonamides-target-splicing-by-inducing-rbm39-degradation-via-recruitment-to-dcaf15
#16
Ting Han, Maria Goralski, Nicholas Gaskill, Emanuela Capota, Jiwoong Kim, Tabitha C Ting, Yang Xie, Noelle S Williams, Deepak Nijhawan
Indisulam is an aryl sulfonamide drug with selective anticancer activity. Its mechanism of action and the basis for its selectivity are unknown. Here we show that indisulam promotes the recruitment of RBM39 (RNA binding motif protein 39) to the CUL4-DCAF15 E3 ubiquitin ligase, leading to RBM39 polyubiquitination and proteasomal degradation. Mutations in RBM39 that prevent its recruitment to CUL4-DCAF15 increase RBM39 stability and confer resistance to indisulam's cytotoxicity. RBM39 associates with pre-mRNA splicing factors, and inactivation of RBM39 by indisulam causes aberrant pre-mRNA splicing...
March 16, 2017: Science
https://www.readbyqxmd.com/read/28280251/the-whole-soil-carbon-flux-in-response-to-warming
#17
Caitlin E Hicks Pries, C Castanha, R Porras, M S Torn
Soil organic carbon harbors three times as much carbon as Earth's atmosphere, and its decomposition is a potentially large climate change feedback and major source of uncertainty in climate projections. The response of whole-soil profiles to warming has not been tested in situ. In this deep warming experiment in mineral soil, CO2 production from all soil depths increased significantly with 4°C warming-annual soil respiration increased by 34-37%. All depths responded to warming with similar temperature sensitivities, driven by decomposition of decadal-aged carbon...
March 9, 2017: Science
https://www.readbyqxmd.com/read/28280250/extremely-efficient-internal-exciton-dissociation-through-edge-states-in-layered-2d-perovskites
#18
J-C Blancon, H Tsai, W Nie, C C Stoumpos, L Pedesseau, C Katan, M Kepenekian, C M M Soe, K Appavoo, M Y Sfeir, S Tretiak, P M Ajayan, M G Kanatzidis, J Even, J J Crochet, A D Mohite
Understanding and controlling charge and energy flow in state-of-the-art semiconductor quantum-wells has enabled high-efficiency optoelectronic devices. Two-dimensional Ruddlesden-Popper perovskites are solution-processed quantum-wells wherein the band gap can be tuned by varying the perovskite layer thickness, which modulates the effective electron-hole confinement. We report that, counterintuitive to classical quantum-confined systems where photo-generated electrons and holes are strongly bound by Coulomb interactions or excitons, the photo-physics of thin films made of Ruddlesden-Popper perovskites with a thickness exceeding two perovskite crystal-units (>1...
March 9, 2017: Science
https://www.readbyqxmd.com/read/28254784/assembly-of-embryonic-and-extra-embryonic-stem-cells-to-mimic-embryogenesis-in-vitro
#19
Sarah Ellys Harrison, Berna Sozen, Neophytos Christodoulou, Christos Kyprianou, Magdalena Zernicka-Goetz
Mammalian embryogenesis requires intricate interactions between embryonic and extra-embryonic tissues to orchestrate and coordinate morphogenesis with changes in developmental potential. Here, we combine mouse embryonic stem cells (ESCs) and extra-embryonic trophoblast stem cells (TSCs) in a 3D-scaffold to generate structures whose morphogenesis is remarkably similar to natural embryos. By using genetically-modified stem cells and specific inhibitors, we show embryogenesis of ESC- and TSC-derived embryos, ETS-embryos, depends on crosstalk involving Nodal signaling...
March 2, 2017: Science
https://www.readbyqxmd.com/read/28254783/deepstack-expert-level-artificial-intelligence-in-heads-up-no-limit-poker
#20
Matej Moravčík, Martin Schmid, Neil Burch, Viliam Lisý, Dustin Morrill, Nolan Bard, Trevor Davis, Kevin Waugh, Michael Johanson, Michael Bowling
Artificial intelligence has seen several breakthroughs in recent years, with games often serving as milestones. A common feature of these games is that players have perfect information. Poker is the quintessential game of imperfect information, and a longstanding challenge problem in artificial intelligence. We introduce DeepStack, an algorithm for imperfect information settings. It combines recursive reasoning to handle information asymmetry, decomposition to focus computation on the relevant decision, and a form of intuition that is automatically learned from self-play using deep learning...
March 2, 2017: Science
journal
journal
20316
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"