Science 2016-01-08.pdf

104 8 JANUARY 2016 VOL 351 ISSUE 6269sciencemag.org SCIENCE8 JANUARY 2016 VOLUME 351 ISSUE 6269CONTENTS124&141Powering forward thermoelectricsNEWSIN BRIEF108 News at a glanceIN DEPTH 110 A RACE TO EXPLAIN BRAZILS SPIKE IN BIRTH DEFECTSEvidence points toward the fast-spreading Zika virus as the cause of microcephaly By G.Vogel111 IRAQ CONFRONTS A NEWENEMYTHE PERSIAN GULFDrought and dams allow saltwater to invade,threatening people and the ancient marshes of Mesopotamia By A.Lawler113 CESIUM FORTIFIES NEXT-GENERATION SOLAR CELLSA dash of the metal could hold the key to making cheap solar cells that can withstand the elements By R.F.Service REPORT P.151114 CONSERVATION RESEARCHERS GETA NEW ROOST IN CAMBRIDGERenovated building aims to foster alliances between academics and advocates By E.Stokstad115 DATA CHECK:FOR FEMALE SCIENTISTS,MIXED FUNDING RESULTS AT U.S.AGENCIES Report to Congress finds a gender disparity in grant awards and a dearth of data By J.MervisFEATURE116 A SHOT AT MIGRAINEDrug companies are racing to prove antibody treatments can prevent the debilitating headaches By E.Underwood PODCASTINSIGHTSPERSPECTIVES 120 ANCIENT GRASSLANDS AT RISKHighly biodiverse tropical grasslands are at risk from forest-planting efforts By W.J.Bond122 LOWER-MANTLE MATERIALSUNDER PRESSURELaboratory measurements provide a window into Earths mantle dynamics By J.Chen REPORT P.144124 FINDING MERIT IN DIVIDING NEIGHBORSThe favorable thermoelectric properties of SnSe are related to its crystal symmetry By K.Behnia REPORT P.141116120125 DISRUPTED NUCLEAR IMPORT-EXPORTIN NEURODEGENERATIONToxicity arises from amyloid-like protein accumulation in the cytoplasm,not the nucleus By S.Da Cruz and D.W.Cleveland REPORT P.173126 POTENCY FINDS ITS NICHESAdult bone marrow employs a surprisingly simple hematopoietic hierarchy By N.Cabezas-Wallscheid and A.Trumpp RESEARCH ARTICLE P.139;REPORT P.176128 BALANCING HYDROPOWER AND BIODIVERSITY IN THE AMAZON,CONGO,AND MEKONGBasin-scale planning is needed to minimize impacts in mega-diverse rivers By K.O.Winemiller et al.BOOKS ET AL.130 TUNNEL VISIONSBy M.Riordan et al.,reviewed by J.Mervis131 A BRIEF HISTORY OF CREATIONBy B.Mesler and H.J.Cleaves II,reviewed by J.StrickLETTERS 132 CALL FOR CONSERVATION:ABANDONED PASTUREBy J.A.C.Poore132 RECOGNIZING THERMALPLASTICITY IN FISHBy A.P.Farrell and C.E.Franklin133 HIV/AIDS EPIDEMIC:THE WHOLE TRUTHBy N.Nathanson133 ERRATAPublished by AAAS8 JANUARY 2016 VOL 351 ISSUE 6269 105SCIENCE sciencemag.org158Life after deathON THE COVERTree of portal blood vessels in the murine fetal liver at embryonic days 12(bottom left),13(bottom right),and 14.5(top),reconstructed in three dimensions from serial cryosections of portal vasculature.Branch surface area is scaled according to fractal geometries,together with the number of hematopoietic stem cells(HSCs;yellow spheres),suggesting that HSC niche expansion is related to portal vessel surface area.See pages 126,139,and 176.Data visualization:Valerie Altounian/Science;base meshes created by Jalal Khan(Icahn School of Medicine at Mount Sinai)using MeshLab147 GEOMORPHOLOGYRepeated catastrophic valley infill following medieval earthquakes in the Nepal Himalaya W.Schwanghart et al.RESEARCH ARTICLE P.140151 SOLAR CELLSA mixed-cation lead mixed-halide perovskite absorber for tandem solar cells D.P.McMeekin et al.NEWS STORY P.113155 FOREST ECOLOGYDominance of the suppressed:Power-law size structure in tropical forests C.E.Farrior et al.158 MICROBIOMEMicrobial community assembly and metabolic function during mammalian corpse decomposition J.L.Metcalf et al.PODCAST162 ANCIENT MICROBIOMEThe 5300-year-old Helicobacter pylori genome of the Iceman F.Maixner et al.165 PALEOCLIMATEReconciliation of the Devils Hole climate record with orbital forcing G.E.Moseley et al.169 CELL BIOLOGYAccurate concentration control of mitochondria and nucleoids R.Jajoo et al.173 PROTEIN AGGREGATESCytoplasmic protein aggregates interfere with nucleocytoplasmic transport of protein and RNA A.C.Woerner et al.PERSPECTIVE P.125176 STEM CELL NICHEFetal liver hematopoietic stem cell niches associate with portal vessels J.A.Khan et al.PERSPECTIVE P.126;RESEARCH ARTICLE P.139180 PROTEIN STRUCTUREThe structure of the-barrel assembly machinery complex J.Bakelar et al.186 CHEMOTAXISPolysialylation controls dendritic cell trafficking by regulating chemokine recognition E.Kiermaier et al.DEPARTMENTS107 EDITORIAL Biggest opportunity of our ageBy Sir David King198 WORKING LIFEWant a letter?You write it for meBy Roger S.DaySCIENCE(ISSN 0036-8075)is published weekly on Friday,except the last week in December,by the American Association for the Advancement of Science,1200 New York Avenue,NW,Washington,DC 20005.Periodicals mail postage(publication No.484460)paid at Washington,DC,and additional mailing offices.Copyright 2016 by the American Association for the Advancement of Science.The title SCIENCE is a registered trademark of the AAAS.Domestic individual membership and s