Readit
We like to keep a list of items that I want to read, analyze, or evaluate, perhaps study, or discard. An intellectual pantry.
If you have comments: Bruce.Bagnoli@gmail.com
A search that results in several things that I'd like to read:
Smart Phone, Smart Science: How the Use of Smartphones Can Revolutionize Research in Cognitive Science
http://www.plosone.org/article/info:doi/10.1371/journal.pone.0024974
Another aspect of the new social web, shifting to more mobile phone based nodes, still largely fixed nodes---yet with emerging capabilities, available to those who understand the technology, it's potential and limits--of course with a new capability, it is the first with the insight and the action who shapes our use of it.
The emerging connection to each other that is emerging on the social network sites combined with the smart phone or smart pad, all connected in ways that both enable good as well as the opportunistic of every moral stripe including some pretty evil characters. So the amplification of the human impulses is both a potential wonder and a potential horror.
These folks are simply extending the understanding of the new smartphone-human connection in the service of scientific inquiry. I extrapolate from there, in two directions. First with a geolocated web of folks able to connect asymmetrically temporally- using collaboration tools such as SharePoint sites and Google maps, second as the knowledge grows about how we think together.
Starting at the simple point of many responding to a stimulus with the elegance of the flexibility of using mobile web technology to distribute measurement and data gathering agents to thousands or more when doing an experiment. The data will be important as is the development of the practical knowledge of how to carry out such experiments.
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Safflower PlantTC and Transformation
http://www.plantmethods.com/content/pdf/1746-4811-7-12.pdf
Includes methods to deal with hyperhydration
by using grafting
quite interesting.
Also interesting to see how reliably the infection transfers genes
increasing agar concentration plus using iota carageen (sp?) was tested and optimum
protocol developed.
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Clostridium ljungdahlii represents a microbial production platform based on syngas
Michael Köpkea,1, Claudia Heldb,2, Sandra Hujera, Heiko Liesegangb, Arnim Wiezerb,3, Antje Wollherrb, Armin Ehrenreichb,2, Wolfgang Lieblc, Gerhard Gottschalkb, and Peter Dürrea,4
+ Author Affiliations
aInstitut für Mikrobiologie und Biotechnologie, Universität Ulm, 89081 Ulm, Germany;
bLaboratorium für Genomanalyse, Institut für Mikrobiologie und Genetik, Georg-August-Universität Göttingen, 37077 Göttingen, Germany; and
cTechnische Universität München, Abteilung Mikrobiologie, Wissenschaftszentrum Weihenstephan, 85354 Freising, Germany
↵1Present address: LanzaTech, 24 Balfour Road, Parnell, Auckland 1052, New Zealand.
↵2Present address: TU München, Abt. Mikrobiologie, Wissenschaftszentrum Weihenstephan, Emil-Ramann-Str. 4, 85354 Freising, Germany.
↵3Present address: Qiagen Hamburg GmbH, Königstr. 4a, 22767 Hamburg, Germany.
Edited by Arnold L. Demain, Drew University, Madison, NJ, and approved June 10, 2010 (received for review April 13, 2010)
Abstract
Clostridium ljungdahlii is an anaerobic homoacetogen, able to ferment sugars, other organic compounds, or CO2/H2 and synthesis gas (CO/H2). The latter feature makes it an interesting microbe for the biotech industry, as important bulk chemicals and proteins can be produced at the expense of CO2, thus combining industrial needs with sustained reduction of CO and CO2 in the atmosphere. Sequencing the complete genome of C. ljungdahlii revealed that it comprises 4,630,065 bp and is one of the largest clostridial genomes known to date. Experimental data and in silico comparisons revealed a third mode of anaerobic homoacetogenic metabolism. Unlike other organisms such as Moorella thermoacetica or Acetobacterium woodii, neither cytochromes nor sodium ions are involved in energy generation. Instead, an Rnf system is present, by which proton translocation can be performed. An electroporation procedure has been developed to transform the organism with plasmids bearing heterologous genes for butanol production. Successful expression of these genes could be demonstrated, leading to formation of the biofuel. Thus, C. ljungdahlii can be used as a unique microbial production platform based on synthesis gas and carbon dioxide/hydrogen mixtures.
biofuels butanol Clostridium acetobutylicum genome sequence Rnf-dependent energy conservation
Footnotes
4To whom correspondence should be addressed. E-mail: peter.duerre@uni-ulm.de. Author contributions: A.E., W.L., G.G., and P.D. designed research; M.K., C.H., S.H., H.L., A. Wiezer, A. Wollherr, and A.E. performed research; and M.K., A.E., G.G, and P.D. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission.
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Engineered bacterial communication prevents Vibrio cholerae virulence in an infant mouse model
Faping Duan and John C. March1
Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY 14853
Edited by Rita R. Colwell, University of Maryland, College Park, MD, and approved May 13, 2010 (received for review February 1, 2010)
Abstract
To investigate the possibility of using commensal bacteria as signal mediators for inhibiting the disease cholera, we stably transformed Escherichia coli Nissle 1917 (Nissle) to express the autoinducer molecule cholera autoinducer 1 (CAI-1) (shown previously to prevent virulence when present with another signaling molecule, autoinducer 2, at high concentrations) and determined the effect on Vibrio cholerae virulence gene expression and colonization in an infant mouse model. We found that pretreatment of mice for 8 h with Nissle engineered to express CAI-1 (Nissle-cqsA) greatly increased the mice’s survival (92%) from ingestion of V. cholerae. Pretreatment with Nissle-cqsA for only 4 h increased survival by 77%, whereas ingesting Nissle-cqsA at the same time as V. cholerae increased survival rates by 27%. Immunostaining revealed an 80% reduction in cholera toxin binding to the intestines of mice pretreated for 8 h with Nissle-cqsA. Further, the numbers of V. cholerae in treated mouse intestines was reduced by 69% after 40 h. This finding points to an easily administered and inexpensive approach where commensal bacteria are engineered to communicate with invasive species and potentially prevent human disease.
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Testosterone decreases trust in socially naïve humans
Peter A. Bosa, David Terburga, and Jack van Honka,b,1
aDepartment of Psychology, Utrecht University, 3584 CS, Utrecht, The Netherlands; and
bDepartment of Psychiatry and Mental Health, University of Cape Town, Groote Schuur Hospital (J-2), Observatory 7925, South Africa
Edited by Bruce S. McEwen, The Rockefeller University, New York, NY, and approved April 23, 2010 (received for review October 9, 2009)
Abstract
Trust plays an important role in the formation and maintenance of human social relationships. But trusting others is associated with a cost, given the prevalence of cheaters and deceivers in human society. Recent research has shown that the peptide hormone oxytocin increases trust in humans. However, oxytocin also makes individuals susceptible to betrayal, because under influence of oxytocin, subjects perseverate in giving trust to others they know are untrustworthy. Testosterone, a steroid hormone associated with competition and dominance, is often viewed as an inhibitor of sociality, and may have antagonistic properties with oxytocin. The following experiment tests this possibility in a placebo-controlled, within-subjects design involving the administration of testosterone to 24 female subjects. We show that compared with the placebo, testosterone significantly decreases interpersonal trust, and, as further analyses established, this effect is determined by those who give trust easily. We suggest that testosterone adaptively increases social vigilance in these trusting individuals to better prepare them for competition over status and valued resources. In conclusion, our data provide unique insights into the hormonal regulation of human sociality by showing that testosterone downregulates interpersonal trust in an adaptive manner.
http://www.pnas.org/content/107/22/9991
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Phys. Plasmas 17, 052708 (2010); doi:10.1063/1.3431094 (6 pages)
Laser-driven plasma jets propagating in an ambient gas studied with optical and proton diagnostics
C. D. Gregory1,
B. Loupias1,
J. Waugh2,
S. Dono3,
S. Bouquet4,
E. Falize4,
Y. Kuramitsu3,
C. Michaut5,
W. Nazarov6,
S. A. Pikuz7,
Y. Sakawa3,
N. C. Woolsey2,
and M. Koenig1
1Laboratoire pour l’Utilisation des Lasers Intenses, UMR7605, CNRS-CEA-Université, Paris VI-Ecole Polytechnique, 91128 Palaiseau Cedex, France Map This map
2Department of Physics, University of York, Heslington YO10 5DD, United Kingdom Map This map
3Institute of Laser Engineering, Osaka University, Suita, Osaka 565-0871, Japan Map This map
4CEA-DAM-DIF, F-91297 Arpajon, France Map This map
5LUTH, Observatoire de Paris, CNRS, Université Paris Diderot, Place Jules Janssen, 92190 Meudon, France Map This map
6School of Chemistry, University of St Andrews, Purdie Blg, St Andrews KY16 9ST, United Kingdom Map This map
7Joint Institute for High Temperatures of RAS, Izhorskaya 13/19, Moscow 125412, Russia Map This map
**** used laser ablation on foam cone
(Received 23 March 2010; accepted 28 April 2010; published online 24 May 2010)
Describes formation of jet from foam cone laser ablation
Loupias et al., Phys. Rev. Lett. 99, 265001 (2007)
Phys. Plasmas 17, 053505 (2010); doi:10.1063/1.3429675 (8 pages)
Jet regime of the afterspark channel decay
S. B. Leonov1,
Y. I. Isaenkov1,
A. A. Firsov1,
S. L. Nothnagel2,
S. F. Gimelshein2,
and M. N. Shneider3
1Joint Institute for High Temperature, RAS, Moscow 125412, Russia Map This map
2University of Southern California, Los Angeles, California 90089, USA Map This map
3Princeton University, Princeton, New Jersey 08544, USA Map This map
(Received 2 February 2010; accepted 22 April 2010; published online 18 May 2010)
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Morris C.E., Kinkel L.L., Xiao K., Prior P., Sands D.C. 2006 Surprising niche for the plant pathogen Pseudomonas syringae. Infection, Genetics and Evolution).
dsands@montana.edu
Role of bacteria in rain and snow is one of David Sands research interests
406-994-5151
Reminds me of one of the first genetic engineering ideas for a marketable product, which was an engineered bacteria for snow making. Carol Moll worked on it at DNAP or something like that. Wonder if this line of research is related. As I recall, there were tests, but folks were scared to release such bacteria and the commercial effort stopped, the company switched to work on tomatoes and carrots or something.
http://pielkeclimatesci.wordpress.com/2010/02/18/guest-weblog-the-enigma...
http://www.montana.edu/cpa/news/nwview.php?article=5659
http://www.nytimes.com/2010/05/25/science/25snow.html.
http://www.montana.edu/cpa/news/nwview.php?article=8546
Also in the Journal "Science" he published recently.
Science 29 February 2008:
Vol. 319. no. 5867, p. 1214
DOI: 10.1126/science.1149757
Prev | Table of Contents | Next
Brevia
Ubiquity of Biological Ice Nucleators in Snowfall
Brent C. Christner,1* Cindy E. Morris,2 Christine M. Foreman,3 Rongman Cai,1 David C. Sands4
Despite the integral role of ice nucleators (IN) in atmospheric processes leading to precipitation, their sources and distributions have not been well established. We examined IN in snowfall from mid- and high-latitude locations and found that the most active were biological in origin. Of the IN larger than 0.2 micrometer that were active at temperatures warmer than -7°C, 69 to 100% were biological, and a substantial fraction were bacteria. Our results indicate that the biosphere is a source of highly active IN and suggest that these biological particles may affect the precipitation cycle and/or their own precipitation during atmospheric transport.
1 Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA.
2 L'Institut Nationale de la Recherche Agronomique, Unité de Pathologie Végétale UR407, F-84140 Montfavet, France.
3 Center for Biofilm Engineering and Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT 59717, USA.
4 Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, MT 59717, USA.
* To whom correspondence should be addressed. E-mail: xner@lsu.edu
Christner, B. C., C. Rongman, C. E. Morris, K. S. McCarter, C. M. Foreman, M. L. Skidmore, S. N. Montross, and D. C. Sands. 2008. Geographic location, season, and precipitation chemistry influence on the abundance and activity of biological ice nucleators in rain and snow. Proc. Nat. Acad. Sci. 105:18854–18859.
http://bio-ice.forumotion.com/
http://news.nationalgeographic.com/news/2009/01/090112-clouds-bacteria.html
and a general discussion of nucleators:
http://www.semp.us/publications/biot_reader.php?BiotID=506
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Functional specificity in the human brain: A window into the functional architecture of the mind
1. Nancy Kanwisher= McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA 02139
Contributed by Nancy Kanwisher, April 16, 2010 (sent for review February 22, 2010)
Footprints of nonsentient design inside the human genome
John C. Avise1
Department of Ecology and Evolutionary Biology, University of California, Irvine, CA, 92697
Abstract
Intelligent design (ID)—the latest incarnation of religious creationism—posits that complex biological features did not accrue gradually via natural evolutionary forces but, instead, were crafted ex nihilo by a cognitive agent. Yet, many complex biological traits are gratuitously complicated, function poorly, and debilitate their bearers. Furthermore, such dysfunctional traits abound not only in the phenotypes but inside the genomes of eukaryotic species. Here, I highlight several outlandish features of the human genome that defy notions of ID by a caring cognitive agent. These range from de novo mutational glitches that collectively kill or maim countless individuals (including embryos and fetuses) to pervasive architectural flaws (including pseudogenes, parasitic mobile elements, and needlessly baroque regulatory pathways) that are endogenous in every human genome. Gross imperfection at the molecular level presents a conundrum for the traditional paradigms of natural theology as well as for recent assertions of ID, but it is consistent with the notion of nonsentient contrivance by evolutionary forces. In this important philosophical sense, the science of evolutionary genetics should rightly be viewed as an ally (not an adversary) of mainstream religions because it helps the latter to escape the profound theological enigmas posed by notions of ID.
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Blocking of Plasmodium transmission by cooperative action of Cecropin A and Defensin A in transgenic Aedes aegypti mosquitoes
Vladimir Kokoza1, Abdouelaziz Ahmed1, Sang Woon Shin1, Nwando Okafor, Zhen Zou, and Alexander S. Raikhel2
+ Author Affiliations
Department of Entomology and Institute for Integrative Genome Biology, University of California, Riverside, CA 92521
Contributed by Alexander S. Raikhel, March 15, 2010 (sent for review August 31, 2009)
↵1V.K., A.A., and S.W.S. contributed equally to this work.
Abstract
To overcome burden of mosquito-borne diseases, multiple control strategies are needed. Population replacement with genetically modified mosquitoes carrying antipathogen effector genes is one of the possible approaches for controlling disease transmission. However, transgenic mosquitoes with antipathogen phenotypes based on overexpression of a single type effector molecule are not efficient in interrupting pathogen transmission. Here, we show that co-overexpression of two antimicrobial peptides (AMP), Cecropin A, and Defensin A, in transgenic Aedes aegypti mosquitoes results in the cooperative antibacterial and antiPlasmodium action of these AMPs. The transgenic hybrid mosquitoes that overexpressed both Cecropin A and Defensin A under the control of the vitellogenin promoter exhibited an elevated resistance to Pseudomonas aeruginosa infection, indicating that these AMPs acted cooperatively against this pathogenic bacterium. In these mosquitoes infected with P. gallinaceum, the number of oocysts was dramatically reduced in midguts, and no sporozoites were found in their salivary glands when the mosquitoes were fed twice to reactivate transgenic AMP production. Infection experiments using the transgenic hybrid mosquitoes, followed by sequential feeding on naive chicken, and then naive wild-type mosquitoes showed that the Plasmodium transmission was completely blocked. This study suggests an approach in generating transgenic mosquitoes with antiPlasmodium refractory phenotype, which is coexpression of two or more effector molecules with cooperative action on the parasite.
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Ever since learning about optical tweezers, I've been interested in manipulation of DNA using optical means. I read with interest how Dr. Stephan Chu (now SecEnergy) stuck latex balls to DNA then used optical means to manipulate it.
When I heard about how Dr. Marcos Maestre was able to use electric fields to manipulate DNA during our lunches at the LBL cafeteria we talked about adding optical tweezers into the mix. At that time, my knowledge had huge holes, and the scientists were kind enough to point me towards better understandings, things that I needed to study. Dr. Carlos Bustamente ( a college and collaborator with Dr. Maestre) later did some fascinating research using some of the tools that interested me. So my scientific intuition was pretty solid, I've picked some area's that proved to be fruitful as the field develops.
The research paper below caught my eye with the term "DNA Nanotweezers", though it turns out that they have a whole different line of interest, yet it's great to see new aspects of how DNA moves and takes it's shape.
APS » Journals » Phys. Rev. Lett. » Volume 104 » Issue 17
Phys. Rev. Lett. 104, 178101 (2010)
DNA Nanotweezers Studied with a Coarse-Grained Model of DNA
Supplemental Material
By
Thomas E. Ouldridge1, Ard A. Louis1, and Jonathan P. K. Doye2
1Rudolf Peierls Centre for Theoretical Physics, 1 Keble Road, Oxford, OX1 3NP, United Kingdom
2Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QZ, United Kingdom
Received 3 November 2009; published 26 April 2010
We introduce a coarse-grained rigid nucleotide model of DNA that reproduces the basic thermodynamics of short strands, duplex hybridization, single-stranded stacking, and hairpin formation, and also captures the essential structural properties of DNA: the helical pitch, persistence length, and torsional stiffness of double-stranded molecules, as well as the comparative flexibility of unstacked single strands. We apply the model to calculate the detailed free-energy landscape of one full cycle of DNA “tweezers,” a simple machine driven by hybridization and strand displacement.
© 2010 The American Physical Society
URL:
http://link.aps.org/doi/10.1103/PhysRevLett.104.178101
DOI:
10.1103/PhysRevLett.104.178101
PACS:
87.14.gk, 34.20.Gj, 81.07.Nb, 87.15.A-
Download: PDF (470 kB)
GeneSearch
http://www.nytimes.com/2010/04/27/science/27gene.html?hpw
http://www.pnas.org/content/107/14/6544.full.pdf+html
APS » Journals » Phys. Rev. Lett. » Volume 104 » Issue 16
Phys. Rev. Lett. 104, 165001 (2010) [4 pages]
Demonstration of the Highest Deuterium-Tritium Areal Density Using Multiple-Picket Cryogenic Designs on OMEGA
Abstract
References
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V. N. Goncharov*, T. C. Sangster, T. R. Boehly, S. X. Hu, I. V. Igumenshchev, F. J. Marshall, R. L. McCrory†, D. D. Meyerhofer†, P. B. Radha, W. Seka, S. Skupsky, and C. Stoeckl
Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
D. T Casey, J. A. Frenje, and R. D. Petrasso
Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
Received 1 December 2009; published 20 April 2010
The performance of triple-picket deuterium-tritium cryogenic target designs on the OMEGA Laser System [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)] is reported. These designs facilitate control of shock heating in low-adiabat inertial confinement fusion targets. Areal densities up to 300 mg/cm2 (the highest ever measured in cryogenic deuterium-tritium implosions) are inferred in the experiments with an implosion velocity ∼3×107 cm/s driven at peak laser intensities of 8×1014 W/cm2. Extension of these designs to ignition on the National Ignition Facility [J. A. Paisner et al., Laser Focus World 30, 75 (1994)] is presented.
© 2010 The American Physical Society
URL:
http://link.aps.org/doi/10.1103/PhysRevLett.104.165001
DOI:
10.1103/PhysRevLett.104.165001
PACS:
52.57.-z
*Also with: Department of Mechanical Engineering, University of Rochester, Rochester, NY 14623, USA.
†Also with: Department of Mechanical Engineering and Department of Physics and Astronomy, University of Rochester, Rochester, NY 14623, USA.
APS » Journals » Phys. Rev. Lett. » Volume 104 » Issue 16
Phys. Rev. Lett. 104, 165002 (2010) [4 pages]
Implosion Experiments using Glass Ablators for Direct-Drive Inertial Confinement Fusion
Abstract
References
No Citing Articles
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V. A. Smalyuk, R. Betti*, J. A. Delettrez, V. Yu. Glebov, D. D. Meyerhofer*, P. B. Radha, S. P. Regan, T. C. Sangster, J. Sanz†, W. Seka, C. Stoeckl, and B. Yaakobi
Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623-1299, USA
J. A. Frenje, C. K. Li, R. D. Petrasso‡, and F. H. Séguin
Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
Received 8 July 2009; published 21 April 2010
Direct-drive implosions with 20-μm-thick glass shells were conducted on the Omega Laser Facility to test the performance of high-Z glass ablators for direct-drive, inertial confinement fusion. The x-ray signal caused by hot electrons generated by two-plasmon-decay instability was reduced by more than ∼40× and hot-electron temperature by ∼2× in the glass compared to plastic ablators at ignition-relevant drive intensities of ∼1×1015 W/cm2, suggesting reduced target preheat. The measured absorption and compression were close to 1D predictions. The measured soft x-ray production in the spectral range of ∼2 to 4 keV was ∼2× to 3× lower than 1D predictions, indicating that the shell preheat caused by soft x-rays is less than predicted. A direct-drive-ignition design based on glass ablators is introduced.
© 2010 The American Physical Society
URL:
http://link.aps.org/doi/10.1103/PhysRevLett.104.165002
DOI:
10.1103/PhysRevLett.104.165002
PACS:
52.57.-z
*Also at Departments of Mechanical Engineering and Physics & Astronomy, University of Rochester, Rochester, NY, USA.
†Also at ETSI Aeronauticos, Universidad Politecnica de Madrid 28040, Spain.
‡Visiting scientist from Laboratory for Laser Energetics, University of Rochester, Rochester, NY, USA.
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Compressing magnetic fields with high-energy lasers
J. P. Knauer, O. V. Gotchev, P. Y. Chang, D. D. Meyerhofer, O. Polomarov, R. Betti, J. A. Frenje, C. K. Li, M. J.-E. Manuel, R. D. Petrasso, J. R. Rygg, and F. H. Séguin
Phys. Plasmas 17, 056318 (2010); doi:10.1063/1.3416557 (8 pages)
Online Publication Date: 12 May 2010
Laser-driven magnetic-field compression producing a magnetic field of tens of megaGauss is reported for the first time. A shock wave formed during the implosion of a cylindrical target traps an initial (seed) magnetic field that is amplified via conservation of magnetic flux. Such large fields are expected to magnetize the electrons in the hot, central plasma, leading to a cyclotron frequency exceeding the collision frequency. The Omega Laser Facility [ T. R. Boehly et al., Opt. Commun. 133, 495 (1997) ] was used to implode cylindrical CH targets filled with deuterium gas and seeded with an external field (>50 kG) from a magnetic pulse generator. This seed field is trapped and rapidly compressed by the imploding shell, minimizing the effect of resistive flux diffusion. The compressed field was probed via proton deflectrometry using 14.7 MeV protons from the D+3He fusion reaction emitted by an imploding glass microballoon. Line-averaged magnetic fields of the imploded core were measured to between 30 and 40 MG. Experimental data were analyzed with both a magnetohydrodynamic version of the one-dimensional hydrocode LILAC [ J. Delettrez et al., Phys. Rev. A 36, 3926 (1987) ; N. W. Jang et al., Bull. Am. Phys. Soc. 51, 144 (2006) ] and the particle propagation code GEANT4 [ S. Agostinelli et al., Nucl. Instrum. Methods Phys. Res. A 506, 250 (2003) ].
Pulsed-power-driven cylindrical liner implosions of laser preheated fuel magnetized with an axial field
S. A. Slutz,
M. C. Herrmann,
R. A. Vesey,
A. B. Sefkow,
D. B. Sinars,
D. C. Rovang,
K. J. Peterson,
and M. E. Cuneo
Phys. Plasmas 17, 056303 (2010); doi:10.1063/1.3333505 (15 pages)
Online Publication Date: 12 March 2010
Abstract
The radial convergence required to reach fusion conditions is considerably higher for cylindrical than for spherical implosions since the volume is proportional to r2 versus r3, respectively. Fuel magnetization and preheat significantly lowers the required radial convergence enabling cylindrical implosions to become an attractive path toward generating fusion conditions. Numerical simulations are presented indicating that significant fusion yields may be obtained by pulsed-power-driven implosions of cylindrical metal liners onto magnetized (>10 T) and preheated (100–500 eV) deuterium-tritium (DT) fuel. Yields exceeding 100 kJ could be possible on Z at 25 MA, while yields exceeding 50 MJ could be possible with a more advanced pulsed power machine delivering 60 MA. These implosions occur on a much shorter time scale than previously proposed implosions, about 100 ns as compared to about 10 μs for magnetic target fusion (MTF) [ I. R. Lindemuth and R. C. Kirkpatrick, Nucl. Fusion 23, 263 (1983) ]. Consequently the optimal initial fuel density (1–5 mg/cc) is considerably higher than for MTF ( ∼ 1 μg/cc). Thus the final fuel density is high enough to axially trap most of the α-particles for cylinders of approximately 1 cm in length with a purely axial magnetic field, i.e., no closed field configuration is required for ignition. According to the simulations, an initial axial magnetic field is partially frozen into the highly conducting preheated fuel and is compressed to more than 100 MG. This final field is strong enough to inhibit both electron thermal conduction and the escape of α-particles in the radial direction. Analytical and numerical calculations indicate that the DT can be heated to 200–500 eV with 5–10 kJ of green laser light, which could be provided by the Z-Beamlet laser. The magneto-Rayleigh-Taylor (MRT) instability poses the greatest threat to this approach to fusion. Two-dimensional Lasnex simulations indicate that the liner walls must have a substantial initial thickness (10–20% of the radius) so that they maintain integrity throughout the implosion. The Z and Z-Beamlet experiments are now being planned to test the various components of this concept, e.g., the laser heating of the fuel and the robustness of liner implosions to the MRT instability.
Show PACS
52.50.Jm Plasma production and heating by laser beams (laser-foil, laser-cluster, etc.)
52.65.-y Plasma simulation
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Google ==>magnetoencephalographic signals filetype=pdf
Reasoning about social conflicts improves into old age
Igor Grossmanna,1, Jinkyung Naa, Michael E. W. Varnuma, Denise C. Parkb, Shinobu Kitayamaa, and Richard E. Nisbetta,1
+ Author Affiliations
aDepartment of Psychology, University of Michigan, Ann Arbor, MI 48109; and
b Center for Vital Longevity, University of Texas at Dallas, Dallas, TX 75235
Contributed by Richard E. Nisbett, February 23, 2010 (sent for review February 2, 2010)
Abstract
It is well documented that aging is associated with cognitive declines in many domains. Yet it is a common lay belief that some aspects of thinking improve into old age. Specifically, older people are believed to show better competencies for reasoning about social dilemmas and conflicts. Moreover, the idea of aging-related gains in wisdom is consistent with views of the aging mind in developmental psychology. However, to date research has provided little evidence corroborating this assumption. We addressed this question in two studies, using a representative community sample. We asked participants to read stories about intergroup conflicts and interpersonal conflicts and predict how these conflicts would unfold. We show that relative to young and middle-aged people, older people make more use of higher-order reasoning schemes that emphasize the need for multiple perspectives, allow for compromise, and recognize the limits of knowledge. Our coding scheme was validated by a group of professional counselors and wisdom researchers. Social reasoning improves with age despite a decline in fluid intelligence. The results suggest that it might be advisable to assign older individuals to key social roles involving legal decisions, counseling, and intergroup negotiations. Furthermore, given the abundance of research on negative effects of aging, this study may help to encourage clinicians to emphasize the inherent strengths associated with aging.
Physical Sciences - Engineering:
Alessandro Spadoni and Chiara Daraio
Generation and control of sound bullets with a nonlinear acoustic lens
PNAS published ahead of print April 5, 2010, doi:10.1073/pnas.1001514107
Acoustic lenses are employed in a variety of applications, from biomedical imaging and surgery to defense systems and damage detection in materials. Focused acoustic signals, for example, enable ultrasonic transducers to image the interior of the human body. Currently however the performance of acoustic devices is limited by their linear operational envelope, which implies relatively inaccurate focusing and low focal power. Here we show a dramatic focusing effect and the generation of compact acoustic pulses (sound bullets) in solid and fluid media, with energies orders of magnitude greater than previously achievable. This focusing is made possible by a tunable, nonlinear acoustic lens, which consists of ordered arrays of granular chains. The amplitude, size, and location of the sound bullets can be controlled by varying the static precompression of the chains. Theory and numerical simulations demonstrate the focusing effect, and photoelasticity experiments corroborate it. Our nonlinear lens permits a qualitatively new way of generating high-energy acoustic pulses, which may improve imaging capabilities through increased accuracy and signal-to-noise ratios and may lead to more effective nonintrusive scalpels, for example, for cancer treatment.
Phys. Rev. Lett. 104, 134801 (2010) [4 pages]
Formation of Optical Bullets in Laser-Driven Plasma Bubble Accelerators
Abstract
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Peng Dong, S. A. Reed, S. A. Yi, S. Kalmykov, G. Shvets, and M. C. Downer*
Department of Physics, University of Texas at Austin, Austin, Texas 78712-1081, USA
N. H. Matlis and W. P. Leemans
Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA
C. McGuffey, S. S. Bulanov, V. Chvykov, G. Kalintchenko, K. Krushelnick, A. Maksimchuk, T. Matsuoka, A. G. R. Thomas, and V. Yanovsky
Center for Ultrafast Optical Science, University of Michigan, 2200 Bonisteel Blvd, Ann Arbor, Michigan 48109-2099, USA
Phys. Rev. Lett. 104, 125001 (2010) [4 pages]
B. Jones1,*, D. J. Ampleford1, R. A. Vesey1, M. E. Cuneo1, C. A. Coverdale1, E. M. Waisman1, M. C. Jones1, W. E. Fowler1, W. A. Stygar1, J. D. Serrano2, M. P. Vigil3, A. A. Esaulov4, V. L. Kantsyrev4, A. S. Safronova4, K. M. Williamson4, A. S. Chuvatin5, and L. I. Rudakov6
1 Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
2 Ktech Corp., Albuquerque, New Mexico 87123, USA
3 LMATA Government Services LLC, Albuquerque, New Mexico 87109, USA
4 University of Nevada, Reno, Nevada 89557, USA
5 Laboratoire de Physique des Plasmas, Ecole Polytechnique, 91128 Palaiseau, France
6 Icarus Research, Bethesda, Maryland 20824-0780, USA
Received 20 November 2009; published 22 March 2010
An indirect drive configuration is proposed wherein multiple compact Z-pinch x-ray sources surround a secondary hohlraum. Planar compact wire arrays allow reduced primary hohlraum surface area compared to cylindrical loads. Implosions of planar arrays are studied at up to 15 TW x-ray power on Saturn with radiated yields exceeding the calculated kinetic energy, suggesting other heating paths. X-ray power and yield scaling studied from 1–6 MA motivates viewfactor modeling of four 6-MA planar arrays producing 90 eV radiation temperature in a secondary hohlraum.
Received 3 September 2009; published 29 March 2010
Electron density bubbles—wake structures generated in plasma of density n̅ e∼1019 cm-3 by the light pressure of intense ultrashort laser pulses—are shown to reshape weak copropagating probe pulses into optical “bullets.” The bullets are reconstructed using frequency-domain interferometric techniques in order to visualize bubble formation. Bullets are confined in three dimensions to plasma-wavelength size, and exhibit higher intensity, broader spectrum and flatter temporal phase than surrounding probe light, evidence of their compression by the bubble. Bullets observed at 0.8≲n̅ e≲1.2×1019 cm-3 provide the first observation of bubble formation below the electron capture threshold. At higher n̅ e, bullets appear with high shot-to-shot stability together with relativistic electrons that vary widely in spectrum, and help relate bubble formation to fast electron generation.
© 2010 The American Physical Society
URL:
http://link.aps.org/doi/10.1103/PhysRevLett.104.134801
DOI:
10.1103/PhysRevLett.104.134801
PACS:
41.75.Jv, 42.40.-i, 52.38.Kd
*downer@physics.utexas.edu
This item is in the subscription section of PNAS:
Production and secretion of fatty acids in genetically engineered cyanobacteria
Xinyao Liua, Daniel Bruneb, Wim Vermaasb, and Roy Curtiss IIIa,b,1
- Author Affiliations
aCenter for Infectious Diseases and Vaccinology, The Biodesign Institute, and
bSchool of Life Sciences, Arizona State University, Tempe, AZ 85287-5401
Contributed by Roy Curtiss, February 24, 2010 (sent for review December 14, 2009)
Abstract
Our purpose is to apply a fatty acid secretion strategy in photosynthetic microbial biofuel production, which will avoid the costly biomass recovery processes currently applied in algal biofuel systems. Starting with introducing acyl-acyl carrier protein thioesterases, we made five successive generations of genetic modifications into cyanobacterium Synechocystis sp. PCC 6803. The mutant strains were able to overproduce fatty acids (C10–C18) and secrete them into the medium at an efficiency of up to 133 ± 12 mg/L of culture per day at a cell density of 1.5 × 108 cells/mL (0.23 g of dry weight/liter). Fatty acid secretion yields were increased by weakening the S layer and peptidoglycan layers. Although the fatty acid secreting strains had a long lag phase with many cells having damaged cell membranes when grown at low cell densities, these strains grew more rapidly in stationary phase and exhibited less cell damage than wild-type in a stationary culture. Our results suggest that fatty acid secreting cyanobacteria are a promising technology for renewable biofuel production.
Footnotes
1To whom correspondence should be addressed: Email: rcurtiss@asu.edu.
Links to story about funders of climate change denial:
http://www.huffingtonpost.com/brendan-demelle/greenpeace-unmasks-koch-i_...
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APS » Journals » Phys. Rev. Lett. » Volume 104 » Issue 20
Phys. Rev. Lett. 104, 207701 (2010) [4 pages]
Quantum Photocell: Using Quantum Coherence to Reduce Radiative Recombination and Increase Efficiency
Marlan O. Scully
Texas A&M University, College Station, Texas 77843, USA
Princeton University, Princeton, New Jersey 08544, USA
Received 18 November 2009; published 21 May 2010
The fundamental limit to photovoltaic efficiency is widely thought to be radiative recombination which balances radiative absorption. We here show that it is possible to break detailed balance via quantum coherence, as in the case of lasing without inversion and the photo-Carnot quantum heat engine. This yields, in principle, a quantum limit to photovoltaic operation which can exceed the classical one. The present work is in complete accord with the laws of thermodynamics.
© 2010 The American Physical Society
URL:http://link.aps.org/doi/10.1103/PhysRevLett.104.207701DOI:10.1103/PhysRevLett.104.207701PACS:84.60.Jt, 64.10.+h
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