| | This journal provides immediate access to some articles. This Week in PNAS Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11099–11100. doi: 10.1073/iti3006103.PMCID: PMC1544047 Commentary HIV-1 Gag: Flipped out for PI(4,5)P2 Eric O. Freed Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11101–11102. Published online 2006 July 17. doi: 10.1073/pnas.0604715103.PMCID: PMC1544048 Physical Sciences Applied Physical Sciences Real-time metabolic imaging Klaes Golman, René in ‘t Zandt, and Mikkel Thaning Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11270–11275. Published online 2006 July 12. doi: 10.1073/pnas.0601319103.PMCID: PMC1544077 Geology A stable isotope aridity index for terrestrial environments Naomi E. Levin, Thure E. Cerling, Benjamin H. Passey, John M. Harris, and James R. Ehleringer Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11201–11205. Published online 2006 July 13. doi: 10.1073/pnas.0604719103.PMCID: PMC1544065 Mathematics Analysis of a Picard modular group Gábor Francsics and Peter D. Lax Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11103–11105. Published online 2006 July 17. doi: 10.1073/pnas.0603075103.PMCID: PMC1544049 Shapes of embedded minimal surfaces Tobias H. Colding and William P. Minicozzi, II Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11106–11111. Published online 2006 July 17. doi: 10.1073/pnas.0510379103.PMCID: PMC1544050 Biological Sciences Biochemistry Active cytosine demethylation triggered by a nuclear receptor involves DNA strand breaks Clémence Kress, Hélène Thomassin, and Thierry Grange Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11112–11117. Published online 2006 July 13. doi: 10.1073/pnas.0601793103.PMCID: PMC1544051 Topoisomerase IIIα and Bloom’s helicase can resolve a mobile double Holliday junction substrate through convergent branch migration Jody L. Plank, Jianhong Wu, and Tao-shih Hsieh Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11118–11123. Published online 2006 July 18. doi: 10.1073/pnas.0604873103.PMCID: PMC1544052 The 2.7-Å crystal structure of a 194-kDa homodimeric fragment of the 6-deoxyerythronolide B synthase Yinyan Tang, Chu-Young Kim, Irimpan I. Mathews, David E. Cane, and Chaitan Khosla Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11124–11129. Published online 2006 July 14. doi: 10.1073/pnas.0601924103.PMCID: PMC1636687 Biophysics A two-dimensional view of the folding energy landscape of cytochrome c James H. Werner, Raymond Joggerst, R. Brian Dyer, and Peter M. Goodwin Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11130–11135. Published online 2006 July 14. doi: 10.1073/pnas.0604712103.PMCID: PMC1544053 Single-molecule dynamics of phytochrome-bound fluorophores probed by fluorescence correlation spectroscopy Abigail E. Miller, Amanda J. Fischer, Ted Laurence, Christopher W. Hollars, Richard J. Saykally, J. Clark Lagarias, and Thomas Huser Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11136–11141. Published online 2006 July 14. doi: 10.1073/pnas.0604724103.PMCID: PMC1544054 Cell Biology A global topology map of the Saccharomyces cerevisiae membrane proteome Hyun Kim, Karin Melén, Marie Österberg, and Gunnar von Heijne Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11142–11147. Published online 2006 July 17. doi: 10.1073/pnas.0604075103.PMCID: PMC1544055 Phenotypic effects of membrane protein overexpression in Saccharomyces cerevisiae Marie Österberg, Hyun Kim, Jonas Warringer, Karin Melén, Anders Blomberg, and Gunnar von Heijne Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11148–11153. Published online 2006 July 17. doi: 10.1073/pnas.0604078103.PMCID: PMC1544056 Ovarian cancer side population defines cells with stem cell-like characteristics and Mullerian Inhibiting Substance responsiveness Paul P. Szotek, Rafael Pieretti-Vanmarcke, Peter T. Masiakos, Daniela M. Dinulescu, Denise Connolly, Rosemary Foster, David Dombkowski, Frederic Preffer, David T. MacLaughlin, and Patricia K. Donahoe Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11154–11159. Published online 2006 July 18. doi: 10.1073/pnas.0603672103.PMCID: PMC1544057 MAGE-A tumor antigens target p53 transactivation function through histone deacetylase recruitment and confer resistance to chemotherapeutic agents Martin Monte, Marta Simonatto, Leticia Y. Peche, Debora R. Bublik, Stefania Gobessi, Marco A. Pierotti, Monica Rodolfo, and Claudio Schneider Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11160–11165. Published online 2006 July 17. doi: 10.1073/pnas.0510834103.PMCID: PMC1544058 Biophysical model of self-organized spindle formation patterns without centrosomes and kinetochores Stuart C. Schaffner and Jorge V. José Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11166–11171. Published online 2006 July 14. doi: 10.1073/pnas.0604721103.PMCID: PMC1544059 Alzheimer's disease β-amyloid peptides are released in association with exosomes Lawrence Rajendran, Masanori Honsho, Tobias R. Zahn, Patrick Keller, Kathrin D. Geiger, Paul Verkade, and Kai Simons Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11172–11177. Published online 2006 July 12. doi: 10.1073/pnas.0603838103.PMCID: PMC1544060 An amphipathic helix targets serum and glucocorticoid-induced kinase 1 to the endoplasmic reticulum-associated ubiquitin-conjugation machinery Maria Francisca Arteaga, Lin Wang, Tommer Ravid, Mark Hochstrasser, and Cecilia M. Canessa Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11178–11183. Published online 2006 July 17. doi: 10.1073/pnas.0604816103.PMCID: PMC1544061 Developmental Biology Influence of sex chromosome constitution on the genomic imprinting of germ cells Gabriela Durcova-Hills, Petra Hajkova, Stephen Sullivan, Sheila Barton, M. Azim Surani, and Anne McLaren Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11184–11188. Published online 2006 July 17. doi: 10.1073/pnas.0602621103.PMCID: PMC1544062 A threshold of GATA4 and GATA6 expression is required for cardiovascular development Mei Xin, Christopher A. Davis, Jeffery D. Molkentin, Ching-Ling Lien, Stephen A. Duncan, James A. Richardson, and Eric N. Olson Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11189–11194. Published online 2006 July 17. doi: 10.1073/pnas.0604604103.PMCID: PMC1544063 From the Cover: Molecular evidence for deep evolutionary roots of bilaterality in animal development David Q. Matus, Kevin Pang, Heather Marlow, Casey W. Dunn, Gerald H. Thomsen, and Mark Q. Martindale Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11195–11200. Published online 2006 July 12. doi: 10.1073/pnas.0601257103.PMCID: PMC1544064 Ecology A stable isotope aridity index for terrestrial environments Naomi E. Levin, Thure E. Cerling, Benjamin H. Passey, John M. Harris, and James R. Ehleringer Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11201–11205. Published online 2006 July 13. doi: 10.1073/pnas.0604719103.PMCID: PMC1544065 From the Cover: Environmental, economic, and energetic costs and benefits of biodiesel and ethanol biofuels Jason Hill, Erik Nelson, David Tilman, Stephen Polasky, and Douglas Tiffany Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11206–11210. Published online 2006 July 12. doi: 10.1073/pnas.0604600103.PMCID: PMC1544066 Parasites dominate food web links Kevin D. Lafferty, Andrew P. Dobson, and Armand M. Kuris Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11211–11216. Published online 2006 July 14. doi: 10.1073/pnas.0604755103.PMCID: PMC1544067 Environmental Sciences Extreme heat reduces and shifts United States premium wine production in the 21st century M. A. White, N. S. Diffenbaugh, G. V. Jones, J. S. Pal, and F. Giorgi Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11217–11222. Published online 2006 July 13. doi: 10.1073/pnas.0603230103.PMCID: PMC1544068 Evolution Rapid Asia–Europe–North America geographic dispersal of earliest Eocene primate Teilhardina during the Paleocene–Eocene Thermal Maximum Thierry Smith, Kenneth D. Rose, and Philip D. Gingerich Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11223–11227. Published online 2006 July 17. doi: 10.1073/pnas.0511296103.PMCID: PMC1544069 Adaptive evolution by mutations in the FLO11 gene Manuel Fidalgo, Ramon R. Barrales, Jose I. Ibeas, and Juan Jimenez Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11228–11233. Published online 2006 July 14. doi: 10.1073/pnas.0601713103.PMCID: PMC1544070 Genetics Mouse genomic representational oligonucleotide microarray analysis: Detection of copy number variations in normal and tumor specimens B. Lakshmi, Ira M. Hall, Christopher Egan, Joan Alexander, Anthony Leotta, John Healy, Lars Zender, Mona S. Spector, Wen Xue, Scott W. Lowe, Michael Wigler, and Robert Lucito Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11234–11239. Published online 2006 July 14. doi: 10.1073/pnas.0602984103.PMCID: PMC1544071 A Sanger/pyrosequencing hybrid approach for the generation of high-quality draft assemblies of marine microbial genomes Susanne M. D. Goldberg, Justin Johnson, Dana Busam, Tamara Feldblyum, Steve Ferriera, Robert Friedman, Aaron Halpern, Hoda Khouri, Saul A. Kravitz, Federico M. Lauro, Kelvin Li, Yu-Hui Rogers, Robert Strausberg, Granger Sutton, Luke Tallon, Torsten Thomas, Eli Venter, Marvin Frazier, and J. Craig Venter Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11240–11245. Published online 2006 July 13. doi: 10.1073/pnas.0604351103.PMCID: PMC1544072 Heritable and stable gene knockdown in rats Christina Tenenhaus Dann, Alma L. Alvarado, Robert E. Hammer, and David L. Garbers Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11246–11251. Published online 2006 July 14. doi: 10.1073/pnas.0604657103.PMCID: PMC1544073 Immunology Glycolipid α-C-galactosylceramide is a distinct inducer of dendritic cell function during innate and adaptive immune responses of mice Shin-ichiro Fujii, Kanako Shimizu, Hiroaki Hemmi, Mikiko Fukui, Anthony J. Bonito, Guangwu Chen, Richard W. Franck, Moriya Tsuji, and Ralph M. Steinman Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11252–11257. Published online 2006 July 14. doi: 10.1073/pnas.0604812103.PMCID: PMC1544074 Transfer of NKG2D and MICB at the cytotoxic NK cell immune synapse correlates with a reduction in NK cell cytotoxic function Pedro Roda-Navarro, Mar Vales-Gomez, Susan E. Chisholm, and Hugh T. Reyburn Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11258–11263. Published online 2006 July 18. doi: 10.1073/pnas.0600721103.PMCID: PMC1544075 Consequences of receptor editing at the λ locus: Multireactivity and light chain secretion Colleen M. Doyle, Jiong Han, Martin G. Weigert, and Eline T. Luning Prak Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11264–11269. Published online 2006 July 17. doi: 10.1073/pnas.0604053103.PMCID: PMC1544076 Medical Sciences Real-time metabolic imaging Klaes Golman, René in ‘t Zandt, and Mikkel Thaning Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11270–11275. Published online 2006 July 12. doi: 10.1073/pnas.0601319103.PMCID: PMC1544077 Transgenic mice rich in endogenous omega-3 fatty acids are protected from colitis Christian A. Hudert, Karsten H. Weylandt, Yan Lu, Jingdong Wang, Song Hong, Axel Dignass, Charles N. Serhan, and Jing X. Kang Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11276–11281. Published online 2006 July 17. doi: 10.1073/pnas.0601280103.PMCID: PMC1544078 Drusen, choroidal neovascularization, and retinal pigment epithelium dysfunction in SOD1-deficient mice: A model of age-related macular degeneration Yutaka Imamura, Setsuko Noda, Kouhei Hashizume, Kei Shinoda, Mineko Yamaguchi, Satoshi Uchiyama, Takahiko Shimizu, Yutaka Mizushima, Takuji Shirasawa, and Kazuo Tsubota Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11282–11287. Published online 2006 July 14. doi: 10.1073/pnas.0602131103.PMCID: PMC1544079 A polymorphism within a conserved β1-adrenergic receptor motif alters cardiac function and β-blocker response in human heart failure Stephen B. Liggett, Jeanne Mialet-Perez, Surai Thaneemit-Chen, Stewart A. Weber, Scott M. Greene, Danielle Hodne, Bradley Nelson, Jennifer Morrison, Michael J. Domanski, Lynne E. Wagoner, William T. Abraham, Jeffrey L. Anderson, John F. Carlquist, Heidi J. Krause-Steinrauf, Laura C. Lazzeroni, J. David Port, Philip W. Lavori, and Michael R. Bristow Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11288–11293. Published online 2006 July 14. doi: 10.1073/pnas.0509937103.PMCID: PMC1523317 Noninvasive imaging of islet grafts using positron-emission tomography Yuxin Lu, Hoa Dang, Blake Middleton, Zesong Zhang, Lorraine Washburn, David B. Stout, Martha Campbell-Thompson, Mark A. Atkinson, Michael Phelps, Sanjiv Sam Gambhir, Jide Tian, and Daniel L. Kaufman Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11294–11299. doi: 10.1073/pnas.0603909103.PMCID: PMC1544080 Antioxidants reduce cone cell death in a model of retinitis pigmentosa Keiichi Komeima, Brian S. Rogers, Lili Lu, and Peter A. Campochiaro Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11300–11305. Published online 2006 July 18. doi: 10.1073/pnas.0604056103.PMCID: PMC1544081 Genes and pathways downstream of telomerase in melanoma metastasis Sepideh Bagheri, Mehdi Nosrati, Shang Li, Sylvia Fong, Sima Torabian, Javier Rangel, Dan H. Moore, Scot Federman, Rebecca R. LaPosa, Frederick L. Baehner, Richard W. Sagebiel, James E. Cleaver, Christopher Haqq, Robert J. Debs, Elizabeth H. Blackburn, and Mohammed Kashani-Sabet Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11306–11311. Published online 2006 July 17. doi: 10.1073/pnas.0510085103.PMCID: PMC1544082 Human prions and plasma lipoproteins Jiri G. Safar, Holger Wille, Michael D. Geschwind, Camille Deering, Diane Latawiec, Ana Serban, David J. King, Giuseppe Legname, Karl H. Weisgraber, Robert W. Mahley, Bruce L. Miller, Stephen J. DeArmond, and Stanley B. Prusiner Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11312–11317. Published online 2006 July 18. doi: 10.1073/pnas.0604021103.PMCID: PMC1544083 Hsp90 inhibition transiently activates Src kinase and promotes Src-dependent Akt and Erk activation Fumitaka Koga, Wanping Xu, Tatiana S. Karpova, James G. McNally, Roland Baron, and Len Neckers Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11318–11322. Published online 2006 July 14. doi: 10.1073/pnas.0604705103.PMCID: PMC1544084 Benefit of farnesoid X receptor inhibition in obstructive cholestasis Catherine Stedman, Christopher Liddle, Sally Coulter, Junichiro Sonoda, Jacqueline G. Alvarez, Ronald M. Evans, and Michael Downes Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11323–11328. Published online 2006 July 14. doi: 10.1073/pnas.0604772103.PMCID: PMC1544085 Utilization of host SR protein kinases and RNA-splicing machinery during viral replication Takeshi Fukuhara, Takamitsu Hosoya, Saki Shimizu, Kengo Sumi, Takako Oshiro, Yoshiyuki Yoshinaka, Masaaki Suzuki, Naoki Yamamoto, Leonore A. Herzenberg, Leonard A. Herzenberg, and Masatoshi Hagiwara Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11329–11333. Published online 2006 July 13. doi: 10.1073/pnas.0604616103.PMCID: PMC1544086 Microbiology Regulation of intracellular free calcium concentration during heterocyst differentiation by HetR and NtcA in Anabaena sp. PCC 7120 Yunming Shi, Weixing Zhao, Wei Zhang, Zi Ye, and Jindong Zhao Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11334–11339. Published online 2006 July 18. doi: 10.1073/pnas.0602839103.PMCID: PMC1544087 Regulatory protein that inhibits both synthesis and use of the target protein controls flagellar phase variation in Salmonella enterica Phillip D. Aldridge, Cheng Wu, Joshua Gnerer, Joyce E. Karlinsey, Kelly T. Hughes, and Matthew S. Sachs Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11340–11345. Published online 2006 July 14. doi: 10.1073/pnas.0602127103.PMCID: PMC1544088 Dissecting virulence pathways of Mycobacterium tuberculosis through protein–protein association Amit Singh, Deborah Mai, Ashwani Kumar, and Adrie J. C. Steyn Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11346–11351. Published online 2006 July 14. doi: 10.1073/pnas.0602817103.PMCID: PMC1544089 Distinguishing features of δ-proteobacterial genomes Samuel Karlin, Luciano Brocchieri, Jan Mrázek, and Dale Kaiser Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11352–11357. Published online 2006 July 14. doi: 10.1073/pnas.0604311103.PMCID: PMC1544090 Electrically conductive bacterial nanowires produced by Shewanella oneidensis strain MR-1 and other microorganisms Yuri A. Gorby, Svetlana Yanina, Jeffrey S. McLean, Kevin M. Rosso, Dianne Moyles, Alice Dohnalkova, Terry J. Beveridge, In Seop Chang, Byung Hong Kim, Kyung Shik Kim, David E. Culley, Samantha B. Reed, Margaret F. Romine, Daad A. Saffarini, Eric A. Hill, Liang Shi, Dwayne A. Elias, David W. Kennedy, Grigoriy Pinchuk, Kazuya Watanabe, Shun’ichi Ishii, Bruce Logan, Kenneth H. Nealson, and Jim K. Fredrickson Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11358–11363. Published online 2006 July 18. doi: 10.1073/pnas.0604517103.PMCID: PMC1544091 From the Cover: Structural basis for targeting HIV-1 Gag proteins to the plasma membrane for virus assembly Jamil S. Saad, Jaime Miller, Janet Tai, Andrew Kim, Ruba H. Ghanam, and Michael F. Summers Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11364–11369. Published online 2006 July 13. doi: 10.1073/pnas.0602818103.PMCID: PMC1544092 Neuroscience A form of motor cortical plasticity that correlates with recovery of function after brain injury Dhakshin Ramanathan, James M. Conner, and Mark H. Tuszynski Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11370–11375. Published online 2006 July 12. doi: 10.1073/pnas.0601065103.PMCID: PMC1544093 Acid-sensitive ionic channels in midbrain dopamine neurons are sensitive to ammonium, which may contribute to hyperammonemia damage Volodymyr I. Pidoplichko and John A. Dani Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11376–11380. Published online 2006 July 17. doi: 10.1073/pnas.0600768103.PMCID: PMC1544094 Cortical systems mediating visual attention to both objects and spatial locations Sarah Shomstein and Marlene Behrmann Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11387–11392. Published online 2006 July 13. doi: 10.1073/pnas.0601813103.PMCID: PMC1544095 The cannabinoid WIN 55,212-2 inhibits transient receptor potential vanilloid 1 (TRPV1) and evokes peripheral antihyperalgesia via calcineurin Amol M. Patwardhan, Nathaniel A. Jeske, Theodore J. Price, Nikita Gamper, Armen N. Akopian, and Kenneth M. Hargreaves Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11393–11398. Published online 2006 July 18. doi: 10.1073/pnas.0603861103.PMCID: PMC1544096 Factors regulating the abundance and localization of synaptobrevin in the plasma membrane Jeremy S. Dittman and Joshua M. Kaplan Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11399–11404. Published online 2006 July 14. doi: 10.1073/pnas.0600784103.PMCID: PMC1544097 Physiology Nonvascular VEGF receptor 3 expression by corneal epithelium maintains avascularity and vision Claus Cursiefen, Lu Chen, Magali Saint-Geniez, Pedram Hamrah, Yiping Jin, Saadia Rashid, Bronislaw Pytowski, Kris Persaud, Yan Wu, J. Wayne Streilein, and Reza Dana Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11405–11410. Published online 2006 July 18. doi: 10.1073/pnas.0506112103.PMCID: PMC1544098 Barttin modulates trafficking and function of ClC-K channels Ute Scholl, Simon Hebeisen, Audrey G. H. Janssen, Gerhard Müller-Newen, Alexi Alekov, and Christoph Fahlke Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11411–11416. Published online 2006 July 18. doi: 10.1073/pnas.0601631103.PMCID: PMC1544099 Plant Biology From the Cover: Development and application of a suite of polysaccharide-degrading enzymes for analyzing plant cell walls Stefan Bauer, Prasanna Vasu, Staffan Persson, Andrew J. Mort, and Chris R. Somerville Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11417–11422. Published online 2006 July 14. doi: 10.1073/pnas.0604632103.PMCID: PMC1544100 Population Biology From the Cover: Globalization and the population structure of Toxoplasma gondii Tovi Lehmann, Paula L. Marcet, Doug H. Graham, Erica R. Dahl, and J. P. Dubey Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11423–11428. Published online 2006 July 18. doi: 10.1073/pnas.0601438103.PMCID: PMC1544101 Social Sciences Sustainability Science From the Cover: Environmental, economic, and energetic costs and benefits of biodiesel and ethanol biofuels Jason Hill, Erik Nelson, David Tilman, Stephen Polasky, and Douglas Tiffany Proc Natl Acad Sci U S A. 2006 July 25; 103(30): 11206–11210. Published online 2006 July 12. doi: 10.1073/pnas.0604600103.PMCID: PMC1544066 |