ALBERT

Description: The reference human genome sequence set the stage for studies of genetic variation and its association with human disease, but epigenomic studies lack a similar reference. To address this need, the NIH Roadmap Epigenomics Consortium generated the largest collection so far of human epigenomes for primary cells and tissues. Here we describe the integrative analysis of 111 reference human epigenomes generated as part of the programme, profiled for histone modification patterns, DNA accessibility, DNA methylation and RNA expression. We establish global maps of regulatory elements, define regulatory modules of coordinated activity, and their likely activators and repressors. We show that disease- and trait-associated genetic variants are enriched in tissue-specific epigenomic marks, revealing biologically relevant cell types for diverse human traits, and providing a resource for interpreting the molecular basis of human disease. Our results demonstrate the central role of epigenomic information for understanding gene regulation, cellular differentiation and human disease.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4530010/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4530010/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Roadmap Epigenomics Consortium -- Kundaje, Anshul -- Meuleman, Wouter -- Ernst, Jason -- Bilenky, Misha -- Yen, Angela -- Heravi-Moussavi, Alireza -- Kheradpour, Pouya -- Zhang, Zhizhuo -- Wang, Jianrong -- Ziller, Michael J -- Amin, Viren -- Whitaker, John W -- Schultz, Matthew D -- Ward, Lucas D -- Sarkar, Abhishek -- Quon, Gerald -- Sandstrom, Richard S -- Eaton, Matthew L -- Wu, Yi-Chieh -- Pfenning, Andreas R -- Wang, Xinchen -- Claussnitzer, Melina -- Liu, Yaping -- Coarfa, Cristian -- Harris, R Alan -- Shoresh, Noam -- Epstein, Charles B -- Gjoneska, Elizabeta -- Leung, Danny -- Xie, Wei -- Hawkins, R David -- Lister, Ryan -- Hong, Chibo -- Gascard, Philippe -- Mungall, Andrew J -- Moore, Richard -- Chuah, Eric -- Tam, Angela -- Canfield, Theresa K -- Hansen, R Scott -- Kaul, Rajinder -- Sabo, Peter J -- Bansal, Mukul S -- Carles, Annaick -- Dixon, Jesse R -- Farh, Kai-How -- Feizi, Soheil -- Karlic, Rosa -- Kim, Ah-Ram -- Kulkarni, Ashwinikumar -- Li, Daofeng -- Lowdon, Rebecca -- Elliott, GiNell -- Mercer, Tim R -- Neph, Shane J -- Onuchic, Vitor -- Polak, Paz -- Rajagopal, Nisha -- Ray, Pradipta -- Sallari, Richard C -- Siebenthall, Kyle T -- Sinnott-Armstrong, Nicholas A -- Stevens, Michael -- Thurman, Robert E -- Wu, Jie -- Zhang, Bo -- Zhou, Xin -- Beaudet, Arthur E -- Boyer, Laurie A -- De Jager, Philip L -- Farnham, Peggy J -- Fisher, Susan J -- Haussler, David -- Jones, Steven J M -- Li, Wei -- Marra, Marco A -- McManus, Michael T -- Sunyaev, Shamil -- Thomson, James A -- Tlsty, Thea D -- Tsai, Li-Huei -- Wang, Wei -- Waterland, Robert A -- Zhang, Michael Q -- Chadwick, Lisa H -- Bernstein, Bradley E -- Costello, Joseph F -- Ecker, Joseph R -- Hirst, Martin -- Meissner, Alexander -- Milosavljevic, Aleksandar -- Ren, Bing -- Stamatoyannopoulos, John A -- Wang, Ting -- Kellis, Manolis -- 5R24HD000836/HD/NICHD NIH HHS/ -- ES017166/ES/NIEHS NIH HHS/ -- F32 HL110473/HL/NHLBI NIH HHS/ -- F32HL110473/HL/NHLBI NIH HHS/ -- K99 HL119617/HL/NHLBI NIH HHS/ -- K99HL119617/HL/NHLBI NIH HHS/ -- P01 DA008227/DA/NIDA NIH HHS/ -- P30AG10161/AG/NIA NIH HHS/ -- P50 MH096890/MH/NIMH NIH HHS/ -- R01 AG015819/AG/NIA NIH HHS/ -- R01 AG017917/AG/NIA NIH HHS/ -- R01 ES024984/ES/NIEHS NIH HHS/ -- R01 ES024992/ES/NIEHS NIH HHS/ -- R01 HG004037/HG/NHGRI NIH HHS/ -- R01 HG007175/HG/NHGRI NIH HHS/ -- R01 HG007354/HG/NHGRI NIH HHS/ -- R01AG15819/AG/NIA NIH HHS/ -- R01AG17917/AG/NIA NIH HHS/ -- R01HG004037/HG/NHGRI NIH HHS/ -- R01HG004037-S1/HG/NHGRI NIH HHS/ -- R01NS078839/NS/NINDS NIH HHS/ -- RC1HG005334/HG/NHGRI NIH HHS/ -- RF1 AG015819/AG/NIA NIH HHS/ -- T32 ES007032/ES/NIEHS NIH HHS/ -- T32 GM007198/GM/NIGMS NIH HHS/ -- T32 GM007266/GM/NIGMS NIH HHS/ -- T32 GM081739/GM/NIGMS NIH HHS/ -- U01 ES017154/ES/NIEHS NIH HHS/ -- U01AG46152/AG/NIA NIH HHS/ -- U01DA025956/DA/NIDA NIH HHS/ -- U01ES017154/ES/NIEHS NIH HHS/ -- U01ES017155/ES/NIEHS NIH HHS/ -- U01ES017156/ES/NIEHS NIH HHS/ -- U01ES017166/ES/NIEHS NIH HHS/ -- Howard Hughes Medical Institute/ -- England -- Nature. 2015 Feb 19;518(7539):317-30. doi: 10.1038/nature14248.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉1] Computer Science and Artificial Intelligence Lab, Massachusetts Institute of Technology, 32 Vassar St, Cambridge, Massachusetts 02139, USA. [2] The Broad Institute of Harvard and MIT, 415 Main Street, Cambridge, Massachusetts 02142, USA. [3] Department of Genetics, Department of Computer Science, 300 Pasteur Dr., Lane Building, L301, Stanford, California 94305-5120, USA. ; 1] Computer Science and Artificial Intelligence Lab, Massachusetts Institute of Technology, 32 Vassar St, Cambridge, Massachusetts 02139, USA. [2] The Broad Institute of Harvard and MIT, 415 Main Street, Cambridge, Massachusetts 02142, USA. ; 1] Computer Science and Artificial Intelligence Lab, Massachusetts Institute of Technology, 32 Vassar St, Cambridge, Massachusetts 02139, USA. [2] The Broad Institute of Harvard and MIT, 415 Main Street, Cambridge, Massachusetts 02142, USA. [3] Department of Biological Chemistry, University of California, Los Angeles, 615 Charles E Young Dr South, Los Angeles, California 90095, USA. ; Canada's Michael Smith Genome Sciences Centre, BC Cancer Agency, 675 West 10th Avenue, Vancouver, British Columbia V5Z 1L3, Canada. ; 1] The Broad Institute of Harvard and MIT, 415 Main Street, Cambridge, Massachusetts 02142, USA. [2] Department of Stem Cell and Regenerative Biology, 7 Divinity Ave, Cambridge, Massachusetts 02138, USA. ; Epigenome Center, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA. ; Department of Cellular and Molecular Medicine, Institute of Genomic Medicine, Moores Cancer Center, Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093, USA. ; Genomic Analysis Laboratory, Howard Hughes Medical Institute &The Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, California 92037, USA. ; Department of Genome Sciences, University of Washington, 3720 15th Ave. NE, Seattle, Washington 98195, USA. ; 1] Computer Science and Artificial Intelligence Lab, Massachusetts Institute of Technology, 32 Vassar St, Cambridge, Massachusetts 02139, USA. [2] The Broad Institute of Harvard and MIT, 415 Main Street, Cambridge, Massachusetts 02142, USA. [3] Biology Department, Massachusetts Institute of Technology, 31 Ames St, Cambridge, Massachusetts 02142, USA. ; The Broad Institute of Harvard and MIT, 415 Main Street, Cambridge, Massachusetts 02142, USA. ; 1] The Broad Institute of Harvard and MIT, 415 Main Street, Cambridge, Massachusetts 02142, USA. [2] The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, 43 Vassar St, Cambridge, Massachusetts 02139, USA. ; 1] Department of Cellular and Molecular Medicine, Institute of Genomic Medicine, Moores Cancer Center, Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093, USA. [2] Ludwig Institute for Cancer Research, 9500 Gilman Drive, La Jolla, California 92093, USA. ; Department of Neurosurgery, Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, 1450 3rd Street, San Francisco, California 94158, USA. ; Department of Pathology, University of California San Francisco, 513 Parnassus Avenue, San Francisco, California 94143-0511, USA. ; Department of Medicine, Division of Medical Genetics, University of Washington, 2211 Elliot Avenue, Seattle, Washington 98121, USA. ; 1] Computer Science and Artificial Intelligence Lab, Massachusetts Institute of Technology, 32 Vassar St, Cambridge, Massachusetts 02139, USA. [2] The Broad Institute of Harvard and MIT, 415 Main Street, Cambridge, Massachusetts 02142, USA. [3] Department of Computer Science &Engineering, University of Connecticut, 371 Fairfield Way, Storrs, Connecticut 06269, USA. ; Department of Microbiology and Immunology and Centre for High-Throughput Biology, University of British Columbia, 2125 East Mall, Vancouver, British Columbia V6T 1Z4, Canada. ; Bioinformatics Group, Department of Molecular Biology, Division of Biology, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia. ; Department of Molecular and Cell Biology, Center for Systems Biology, The University of Texas, Dallas, NSERL, RL10, 800 W Campbell Road, Richardson, Texas 75080, USA. ; Department of Genetics, Center for Genome Sciences and Systems Biology, Washington University in St Louis, 4444 Forest Park Ave, St Louis, Missouri 63108, USA. ; Institute for Molecular Bioscience, University of Queensland, St Lucia, Queensland 4072, Australia. ; 1] The Broad Institute of Harvard and MIT, 415 Main Street, Cambridge, Massachusetts 02142, USA. [2] Brigham &Women's Hospital, 75 Francis Street, Boston, Massachusetts 02115, USA. ; 1] Department of Genetics, Center for Genome Sciences and Systems Biology, Washington University in St Louis, 4444 Forest Park Ave, St Louis, Missouri 63108, USA. [2] Department of Computer Science and Engineeering, Washington University in St. Louis, St. Louis, Missouri 63130, USA. ; 1] Department of Applied Mathematics and Statistics, Stony Brook University, Stony Brook, New York 11794-3600, USA. [2] Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA. ; Molecular and Human Genetics Department, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA. ; Biology Department, Massachusetts Institute of Technology, 31 Ames St, Cambridge, Massachusetts 02142, USA. ; 1] The Broad Institute of Harvard and MIT, 415 Main Street, Cambridge, Massachusetts 02142, USA. [2] Brigham &Women's Hospital, 75 Francis Street, Boston, Massachusetts 02115, USA. [3] Harvard Medical School, 25 Shattuck St, Boston, Massachusetts 02115, USA. ; Department of Biochemistry, Keck School of Medicine, University of Southern California, 1450 Biggy Street, Los Angeles, California 90089-9601, USA. ; ObGyn, Reproductive Sciences, University of California San Francisco, 35 Medical Center Way, San Francisco, California 94143, USA. ; Center for Biomolecular Sciences and Engineering, University of Santa Cruz, 1156 High Street, Santa Cruz, California 95064, USA. ; 1] Canada's Michael Smith Genome Sciences Centre, BC Cancer Agency, 675 West 10th Avenue, Vancouver, British Columbia V5Z 1L3, Canada. [2] Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia V5A 1S6, Canada. [3] Department of Medical Genetics, University of British Columbia, 2329 West Mall, Vancouver, BC, Canada, V6T 1Z4. ; Dan L. Duncan Cancer Center, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA. ; 1] Canada's Michael Smith Genome Sciences Centre, BC Cancer Agency, 675 West 10th Avenue, Vancouver, British Columbia V5Z 1L3, Canada. [2] Department of Medical Genetics, University of British Columbia, 2329 West Mall, Vancouver, BC, Canada, V6T 1Z4. ; Department of Microbiology and Immunology, Diabetes Center, University of California, San Francisco, 513 Parnassus Ave, San Francisco, California 94143-0534, USA. ; 1] University of Wisconsin, Madison, Wisconsin 53715, USA. [2] Morgridge Institute for Research, 330 N. Orchard Street, Madison, Wisconsin 53707, USA. ; USDA/ARS Children's Nutrition Research Center, Baylor College of Medicine, 1100 Bates Street, Houston, Texas 77030, USA. ; 1] Department of Molecular and Cell Biology, Center for Systems Biology, The University of Texas, Dallas, NSERL, RL10, 800 W Campbell Road, Richardson, Texas 75080, USA. [2] Bioinformatics Division, Center for Synthetic and Systems Biology, TNLIST, Tsinghua University, Beijing 100084, China. ; National Institute of Environmental Health Sciences, 111 T.W. Alexander Drive, Research Triangle Park, North Carolina 27709, USA. ; 1] The Broad Institute of Harvard and MIT, 415 Main Street, Cambridge, Massachusetts 02142, USA. [2] Massachusetts General Hospital, 55 Fruit St, Boston, Massachusetts 02114, USA. [3] Howard Hughes Medical Institute, 4000 Jones Bridge Road, Chevy Chase, Maryland 20815-6789, USA. ; 1] Canada's Michael Smith Genome Sciences Centre, BC Cancer Agency, 675 West 10th Avenue, Vancouver, British Columbia V5Z 1L3, Canada. [2] Department of Microbiology and Immunology and Centre for High-Throughput Biology, University of British Columbia, 2125 East Mall, Vancouver, British Columbia V6T 1Z4, Canada.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25693563" target="_blank"〉PubMed〈/a〉

Description: We report photovoltaic response of highly transparent graphene/BiFe 0.95 Si 0.05 O 3 (BFSiO)/ITO/glass derived from bottom-up spin coating technique. The device exhibits short-circuit-current (I SC 0.75 mA) with 1000 fold upsurge and open-circuit-voltage (V OC  ∼ 0.45 V) under standard AM 1.5 illumination through graphene. In combination, I SC of 0.63 mA and V OC of 0.35 V for same illumination through ITO, reveals the prospects of harvesting indoor light. Also, crystallographic structure, red shift in band gap, leakage behavior, and ferroelectric characteristics of BFSiO thin films are reported. Reproducible transient response of I SC and V OC with quick switching (

Description: We present the first measurements of reaction-in-flight (RIF) neutrons in an inertial confinement fusion system. The experiments were carried out at the National Ignition Facility, using both Low Foot and High Foot drives and cryogenic plastic capsules. In both cases, the high-energy RIF ( E n 〉 15 MeV) component of the neutron spectrum was found to be about 10 −4 of the total. The majority of the RIF neutrons were produced in the dense cold fuel surrounding the burning hotspot of the capsule, and the data are consistent with a compressed cold fuel that is moderately to strongly coupled ( Γ ∼ 0.6) and electron degenerate ( θ Fermi / θ e ∼ 4). The production of RIF neutrons is controlled by the stopping power in the plasma. Thus, the current RIF measurements provide a unique test of stopping power models in an experimentally unexplored plasma regime. We find that the measured RIF data strongly constrain stopping models in warm dense plasma conditions, and some models are ruled out by our analysis of these experiments.

Description: Implementing nonlinear transmission line (NLTL) technology in the design of a high power microwave source has the benefits of producing a comparatively small and lightweight solid-state system where the emission frequency is easily tuned. Usually, smaller in physical size, single NLTLs may produce significantly less power than its vacuum based counterparts. However, combining individual NLTL outputs electrically or in free-space is an attractive solution to achieve greater output power. This paper discusses a method for aligning a four element NLTL antenna array with coaxial geometry using easily adjustable temporal delay lines. These delay lines, sometimes referred to as pulse shock lines or pulse sharpening lines, are placed serially in front of the main NLTL line. The propagation velocity in each delay line is set by the voltage amplitude of an incident pulse as well as the magnetic field bias. Each is adjustable although for the system described in this paper, the voltage is held constant while the bias is changed through applying an external DC magnetic field of varying magnitude. Three different ferrimagnetic materials are placed in the temporal delay line to evaluate which yields the greatest range of electrical delay with the least amount of variability from consecutive shots.

Description: The direct-drive, laser-based approach to inertial confinement fusion (ICF) is reviewed from its inception following the demonstration of the first laser to its implementation on the present generation of high-power lasers. The review focuses on the evolution of scientific understanding gained from target-physics experiments in many areas, identifying problems that were demonstrated and the solutions implemented. The review starts with the basic understanding of laser–plasma interactions that was obtained before the declassification of laser-induced compression in the early 1970s and continues with the compression experiments using infrared lasers in the late 1970s that produced thermonuclear neutrons. The problem of suprathermal electrons and the target preheat that they caused, associated with the infrared laser wavelength, led to lasers being built after 1980 to operate at shorter wavelengths, especially 0.35  μ m—the third harmonic of the Nd:glass laser—and 0.248  μ m (the KrF gas laser). The main physics areas relevant to direct drive are reviewed. The primary absorption mechanism at short wavelengths is classical inverse bremsstrahlung. Nonuniformities imprinted on the target by laser irradiation have been addressed by the development of a number of beam-smoothing techniques and imprint-mitigation strategies. The effects of hydrodynamic instabilities are mitigated by a combination of imprint reduction and target designs that minimize the instability growth rates. Several coronal plasma physics processes are reviewed. The two-plasmon–decay instability, stimulated Brillouin scattering (together with cross-beam energy transfer), and (possibly) stimulated Raman scattering are identified as potential concerns, placing constraints on the laser intensities used in target designs, while other processes (self-focusing and filamentation, the parametric decay instability, and magnetic fields), once considered important, are now of lesser concern for mainline direct-drive target concepts. Filamentation is largely suppressed by beam smoothing. Thermal transport modeling, important to the interpretation of experiments and to target design, has been found to be nonlocal in nature. Advances in shock timing and equation-of-state measurements relevant to direct-drive ICF are reported. Room-temperature implosions have provided an increased understanding of the importance of stability and uniformity. The evolution of cryogenic implosion capabilities, leading to an extensive series carried out on the 60-beam OMEGA laser [Boehly et al. , Opt. Commun. 133 , 495 (1997)], is reviewed together with major advances in cryogenic target formation. A polar-drive concept has been developed that will enable direct-drive–ignition experiments to be performed on the National Ignition Facility [Haynam et al. , Appl. Opt. 46 (16), 3276 (2007)]. The advantages offered by the alternative approaches of fast ignition and shock ignition and the issues associated with these concepts are described. The lessons learned from target-physics and implosion experiments are taken into account in ignition and high-gain target designs for laser wavelengths of 1/3  μ m and 1/4  μ m. Substantial advances in direct-drive inertial fusion reactor concepts are reviewed. Overall, the progress in scientific understanding over the past five decades has been enormous, to the point that inertial fusion energy using direct drive shows significant promise as a future environmentally attractive energy source.

Description: This paper describes the analysis procedure applied to the thermal measurements on the rear side of a carbon fibre composite calorimeter with the purpose of reconstructing the energy flux due to an ion beam colliding on the front side. The method is based on the transfer function technique and allows a fast analysis by means of the fast Fourier transform algorithm. Its efficacy has been tested both on simulated and measured temperature profiles: in all cases, the energy flux features are well reproduced and beamlets are well resolved. Limits and restrictions of the method are also discussed, providing strategies to handle issues related to signal noise and digital processing.

Description: The second-order non-Navier-Fourier constitutive laws, expressed in a compact algebraic mathematical form, were validated for the force-driven Poiseuille gas flow by the deterministic atomic-level microscopic molecular dynamics (MD). Emphasis is placed on how completely different methods (a second-order continuum macroscopic theory based on the kinetic Boltzmann equation, the probabilistic mesoscopic direct simulation Monte Carlo, and, in particular, the deterministic microscopic MD) describe the non-classical physics, and whether the second-order non-Navier-Fourier constitutive laws derived from the continuum theory can be validated using MD solutions for the viscous stress and heat flux calculated directly from the molecular data using the statistical method. Peculiar behaviors (non-uniform tangent pressure profile and exotic instantaneous heat conduction from cold to hot [R. S. Myong, “A full analytical solution for the force-driven compressible Poiseuille gas flow based on a nonlinear coupled constitutive relation,” Phys. Fluids 23 (1), 012002 (2011)]) were re-examined using atomic-level MD results. It was shown that all three results were in strong qualitative agreement with each other, implying that the second-order non-Navier-Fourier laws are indeed physically legitimate in the transition regime. Furthermore, it was shown that the non-Navier-Fourier constitutive laws are essential for describing non-zero normal stress and tangential heat flux, while the classical and non-classical laws remain similar for shear stress and normal heat flux.

Description: This article presents the simulation, fabrication, and experimental characterization of a surface plasmonic resonance (SPR) sensor integrated with an acoustic sensing compatible substrate. The SPR sensor is designed to work in the visible region with gold nanodisc arrays fabricated on LiNbO 3 , which is both piezoelectric and birefringent. A linear relationship between resonance wavelength and varying liquid refractive indices were observed in experiments, and a sensitivity of 165 nm/refractive index unit was obtained. Polarization effects of the birefringent property of the Y-cut LiNbO 3 substrate have been investigated, which can also be applied to X-cut LiNbO 3 . Our study demonstrates the feasibility of an SPR sensor device utilizing a birefringent substrate, which has acoustic wave compatibility and can pave the way toward much more robust and flexible biosensing devices.

Description: A constant magnetic field can significantly improve the quality and speed of ablation by nanosecond laser pulses. These improvements are usually attributed to the confinement of laser-produced plasma by the magnetic field and specific propagation effects in the magnetized plasma. Here we report a strong influence of constant axial magnetic field on the ablation of silicon by 20-ns laser pulses at wavelength 355 nm, which results in an increase of ablation depth by a factor of 1.3 to 69 depending on laser parameters and magnitude of the magnetic field. The traditional plasma effects do not explain this result, and magneto-absorption of silicon is proposed as one of the major mechanisms of the significant enhancement of ablation.

Description: The high-temperature ferromagnet MnBi continues to receive attention as a candidate to replace rare-earth-containing permanent magnets in applications above room temperature. This is due to a high Curie temperature, large magnetic moments, and a coercivity that increases with temperature. The synthesis of MnBi also allows for crystals that are free of interstitial Mn, enabling more direct access to the key interactions underlying the physical properties of binary Mn-based ferromagnets. In this work, we use inelastic neutron scattering to measure the spin waves of MnBi in order to characterize the magnetic exchange at low temperature. Consistent with the spin reorientation that occurs below 140 K, we do not observe a spin gap in this system above our experimental resolution. A Heisenberg model was fit to the spin wave data in order to characterize the long-range nature of the exchange. It was found that interactions up to sixth nearest neighbor are required to fully parametrize the spin waves. Surprisingly, the nearest-neighbor term is antiferromagnetic, and the realization of a ferromagnetic ground state relies on the more numerous ferromagnetic terms beyond nearest neighbor, suggesting that the ferromagnetic ground state arises as a consequence of the long-ranged interactions in the system.