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Search Results: 1 - 10 of 199578 matches for " Jonathan G. Lundgren "
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Bacterial Gut Symbionts Contribute to Seed Digestion in an Omnivorous Beetle
Jonathan G. Lundgren,R. Michael Lehman
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0010831
Abstract: Obligate bacterial symbionts alter the diets of host animals in numerous ways, but the ecological roles of facultative bacterial residents that colonize insect guts remain unclear. Carabid beetles are a common group of beneficial insects appreciated for their ability to consume insect prey and seeds, but the contributions of microbes to diet diversification in this and similar groups of facultative granivores are largely unknown.
Bt Crop Effects on Functional Guilds of Non-Target Arthropods: A Meta-Analysis
L. LaReesa Wolfenbarger, Steven E. Naranjo, Jonathan G. Lundgren, Royce J. Bitzer, Lidia S. Watrud
PLOS ONE , 2008, DOI: 10.1371/journal.pone.0002118
Abstract: Background Uncertainty persists over the environmental effects of genetically-engineered crops that produce the insecticidal Cry proteins of Bacillus thuringiensis (Bt). We performed meta-analyses on a modified public database to synthesize current knowledge about the effects of Bt cotton, maize and potato on the abundance and interactions of arthropod non-target functional guilds. Methodology/Principal Findings We compared the abundance of predators, parasitoids, omnivores, detritivores and herbivores under scenarios in which neither, only the non-Bt crops, or both Bt and non-Bt crops received insecticide treatments. Predators were less abundant in Bt cotton compared to unsprayed non-Bt controls. As expected, fewer specialist parasitoids of the target pest occurred in Bt maize fields compared to unsprayed non-Bt controls, but no significant reduction was detected for other parasitoids. Numbers of predators and herbivores were higher in Bt crops compared to sprayed non-Bt controls, and type of insecticide influenced the magnitude of the difference. Omnivores and detritivores were more abundant in insecticide-treated controls and for the latter guild this was associated with reductions of their predators in sprayed non-Bt maize. No differences in abundance were found when both Bt and non-Bt crops were sprayed. Predator-to-prey ratios were unchanged by either Bt crops or the use of insecticides; ratios were higher in Bt maize relative to the sprayed non-Bt control. Conclusions/Significance Overall, we find no uniform effects of Bt cotton, maize and potato on the functional guilds of non-target arthropods. Use of and type of insecticides influenced the magnitude and direction of effects; insecticde effects were much larger than those of Bt crops. These meta-analyses underscore the importance of using controls not only to isolate the effects of a Bt crop per se but also to reflect the replacement of existing agricultural practices. Results will provide researchers with information to design more robust experiments and will inform the decisions of diverse stakeholders regarding the safety of transgenic insecticidal crops.
Understanding and Enhancing Soil Biological Health: The Solution for Reversing Soil Degradation
R. Michael Lehman,Cynthia A. Cambardella,Diane E. Stott,Veronica Acosta-Martinez,Daniel K. Manter,Jeffrey S. Buyer,Jude E. Maul,Jeffrey L. Smith,Harold P. Collins,Jonathan J. Halvorson,Robert J. Kremer,Jonathan G. Lundgren,Tom F. Ducey,Virginia L. Jin,Douglas L. Karlen
Sustainability , 2015, DOI: 10.3390/su7010988
Abstract: Our objective is to provide an optimistic strategy for reversing soil degradation by increasing public and private research efforts to understand the role of soil biology, particularly microbiology, on the health of our world’s soils. We begin by defining soil quality/soil health (which we consider to be interchangeable terms), characterizing healthy soil resources, and relating the significance of soil health to agroecosystems and their functions. We examine how soil biology influences soil health and how biological properties and processes contribute to sustainability of agriculture and ecosystem services. We continue by examining what can be done to manipulate soil biology to: (i) increase nutrient availability for production of high yielding, high quality crops; (ii) protect crops from pests, pathogens, weeds; and (iii) manage other factors limiting production, provision of ecosystem services, and resilience to stresses like droughts. Next we look to the future by asking what needs to be known about soil biology that is not currently recognized or fully understood and how these needs could be addressed using emerging research tools. We conclude, based on our perceptions of how new knowledge regarding soil biology will help make agriculture more sustainable and productive, by recommending research emphases that should receive first priority through enhanced public and private research in order to reverse the trajectory toward global soil degradation.
Cross-diagnostic validity in a generic instrument: an example from the Functional Independence Measure in Scandinavia
Lundgren-Nilsson, A Tennant, G Grimby, KS Sunnerhagen
Health and Quality of Life Outcomes , 2006, DOI: 10.1186/1477-7525-4-55
Abstract: Data from 471 patients on FIM? motor items at admission (stroke 157, spinal cord injury 157 and traumatic brain injury 157), age range 11–90 years and 70 % male in nine rehabilitation facilities in Scandinavia, were fitted to the Rasch model. A detailed analysis of scoring functions of the seven categories of the FIM? motor items was made prior to testing fit to the model. Categories were re-scored where necessary. Fit to the model was assessed initially within diagnosis and then in the pooled data. Analysis of Differential Item Functioning (DIF) was undertaken in the pooled data for the FIM? motor scale. Comparability of sum scores between diagnoses was tested by Test Equating.The present seven category scoring system for the FIM? motor items was found to be invalid, necessitating extensive rescoring. Despite rescoring, the item-trait interaction fit statistic was significant and two individual items showed misfit to the model, Eating and Bladder management. DIF was also found for Spinal Cord Injury, compared with the other two diagnoses. After adjustment, it was possible to make appropriate comparisons of sum scores between the three diagnoses.The seven-category response function is a problem for the FIM? instrument, and a reduction of responses might increase the validity of the instrument. Likewise, the removal of items that do not fit the underlying trait would improve the validity of the scale in these groups. Cross-diagnostic DIF is also a problem but for clinical use sum scores on group data in a generic instrument such as the FIM? can be compared with appropriate adjustments. Thus, when planning interventions (group or individual), developing rehabilitation programs or comparing patient achievements in individual items, cross-diagnostic DIF must be taken into account.Medical outcome studies use generic instruments to compare results between different settings with different case mixes. It is generally thought that they give less information about each patie
Momentum-Space Entanglement Spectrum of Bosons and Fermions with Interactions
Rex Lundgren,Jonathan Blair,Martin Greiter,Andreas L?uchli,Gregory A. Fiete,Ronny Thomale
Physics , 2014, DOI: 10.1103/PhysRevLett.113.256404
Abstract: We study the momentum space entanglement spectra of bosonic and fermionic formulations of the spin-1/2 XXZ chain with analytical methods and exact diagonalization. We investigate the behavior of the entanglement gaps, present in both partitions, across quantum phase transitions in the XXZ chain. In both cases, finite size scaling reveals that the entanglement gap closure does not occur at the physical transition points. For bosons, we find that the entanglement gap observed in [Thomale et al., Phys. Rev. Lett. 105, 116805 (2010)] depends on the scaling dimension of the conformal field theory as varied by the XXZ anisotropy. For fermions, the infinite entanglement gap present at the XX point persists well past the phase transition at the Heisenberg point. We elaborate on how these shifted transition points in the entanglement spectra may in fact support the numerical study of physical transitions in the momentum space density matrix renormalization group.
Confirmation of Small Dynamical and Stellar Masses for Extreme Emission Line Galaxies at z~2
Michael V. Maseda,Arjen van der Wel,Elisabete da Cunha,Hans-Walter Rix,Camilla Pacifici,Ivelina Momcheva,Gabriel B. Brammer,Marijn Franx,Pieter van Dokkum,Eric F. Bell,Mattia Fumagalli,Norman A. Grogin,Dale D. Kocevski,Anton M. Koekemoer,Britt F. Lundgren,Danilo Marchesini,Erica J. Nelson,Shannon G. Patel,Rosalind E. Skelton,Amber N. Straughn,Jonathan R. Trump,Benjamin J. Weiner,Katherine E. Whitaker,Stijn Wuyts
Physics , 2013, DOI: 10.1088/2041-8205/778/1/L22
Abstract: Spectroscopic observations from the Large Binocular Telescope and the Very Large Telescope reveal kinematically narrow lines (~50 km/s) for a sample of 14 Extreme Emission Line Galaxies (EELGs) at redshifts 1.4 < z < 2.3. These measurements imply that the total dynamical masses of these systems are low (< 3x10^9 M_sun). Their large [O III] 5007 equivalent widths (500-1100 Angstroms) and faint blue continuum emission imply young ages of 10-100 Myr and stellar masses of 10^8-10^9 M_sun, confirming the presence of a violent starburst. The dynamical masses represent the first such determinations for low-mass galaxies at z > 1. The stellar mass formed in this vigorous starburst phase represents a large fraction of the total (dynamical) mass, without a significantly massive underlying population of older stars. The occurrence of such intense events in shallow potentials strongly suggests that supernova-driven winds must be of critical importance in the subsequent evolution of these systems.
The Nature of Extreme Emission Line Galaxies at z=1-2: Kinematics and Metallicities from Near-Infrared Spectroscopy
Michael V. Maseda,Arjen van der Wel,Hans-Walter Rix,Elisabete da Cunha,Camilla Pacifici,Ivelina Momcheva,Gabriel B. Brammer,Sharon E. Meidt,Marijn Franx,Pieter van Dokkum,Mattia Fumagalli,Eric F. Bell,Henry C. Ferguson,Natascha M. F?rster-Schreiber,Anton M. Koekemoer,David C. Koo,Britt F. Lundgren,Danilo Marchesini,Erica J. Nelson,Shannon G. Patel,Rosalind E. Skelton,Amber N. Straughn,Jonathan R. Trump,Katherine E. Whitaker
Physics , 2014, DOI: 10.1088/0004-637X/791/1/17
Abstract: We present near-infrared spectroscopy of a sample of 22 Extreme Emission Line Galaxies at redshifts 1.3 < z < 2.3, confirming that these are low-mass (M* = 10^8 - 10^9 M_sun) galaxies undergoing intense starburst episodes (M*/SFR ~ 10-100 Myr). The sample is selected by [O III] or H{\alpha} emission line flux and equivalent width using near-infrared grism spectroscopy from the 3D-HST survey. High-resolution NIR spectroscopy is obtained with LBT/LUCI and VLT/X-SHOOTER. The [O III]/H{\beta} line ratio is high (> 5) and [N II]/H{\alpha} is always significantly below unity, which suggests a low gas-phase metallicity. We are able to determine gas-phase metallicities for 7 of our objects using various strong-line methods, with values in the range 0.05-0.30 Z_sun and with a median of 0.15 Z_sun; for 3 of these objects we detect [O III]{\lambda}4363 which allows for a direct constraint on the metallicity. The velocity dispersion, as measured from the nebular emission lines, is typically ~50 km/s. Combined with the observed star-forming activity, the Jeans and Toomre stability criteria imply that the gas fraction must be large (> 2/3), consistent with the difference between our dynamical and stellar mass estimates. The implied gas depletion time scale (several hundred Myr) is substantially longer than the inferred mass-weighted ages (~50 Myr), which further supports the emerging picture that most stars in low-mass galaxies form in short, intense bursts of star formation.
Informed consent - where do we stand in South Africa in 2004?: comment
Christina Lundgren
Southern African Journal of Anaesthesia and Analgesia , 2004,
Live From Moscow: The Celebration Of Yuri Gagarin And Transnational Television In Europe
Lars Lundgren
View : Journal of European Television History and Culture , 2012,
Abstract: On April 14th, 1961, television viewers across Europe watched live images of Yuri Gagarin being celebrated on the Red Square in Moscow. The broadcast was made possible by the linking of the Intervision and Eurovision television networks, which was the result of cooperation between broadcasters on both sides of the Iron Curtain. By looking into how the co-operation between the OIRT and EBU was gradually developed between 1957 and 1961 this article engages with the interplay between cultural, legal and technological aspects of broadcasting and how the transnational broadcast of Gagarin’s return to Moscow was made possible. The article furthermore argues the need to understand early television in Europe as a dialectic between the national and the transnational and shows how the live transmission network binding the East and West together was the result of an interplay between structures provided by transnational organisations such as the OIRT and EBU, and initiatives by national broadcasting organisations.
When to start: not so fast
Lundgren J
Journal of the International AIDS Society , 2012, DOI: 10.7448/ias.15.6.18071
Abstract: It remains controversial whether and, if so, the extent to which antiretroviral therapy (ART) results in net benefit if used by HIV-positive persons with a high CD4 count, particularly those with early HIV infection. This controversy is primarily reflecting lack of solid evidence from randomized controlled trials. Currently published trials have compared early ART with initiation of ART below currently globally accepted thresholds for initiation (i.e. CD4 count at 350 cells/μL) and, hence, are unable to inform this discussion. Analyses on large observational studies that have attempted to address this question have shown inconsistent results; therefore, those results are considered low-quality evidence, as per the GRADE criteria used by, for example, WHO when formulating guidelines. In resource-constrained regions, not even observational data are available to inform this question. The START study is underway to answer this question. Data remain blinded, but START may show net harm from early use of ART; such a result would severely undermine use of ART as prevention in early HIV infection. Prescription of any type of medicine is guided by the principle of “do no harm” – that is, “the doctor should not prescribe medications unless s/he knows that the treatment is unlikely to be harmful.” Hence, the balance of risk/benefit to individuals versus prevention benefit is important to accurately determine, and current guidelines of generally initiating ART once the patient develops HIV-related symptoms or the CD4 count drops to levels around 350 cells/μL should be adhered to until further evidence has emerged.
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