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Description

In this synthesis, we hope to accomplish two things: 1) reflect on how the analysis of the new archaeological cases presented in this special feature adds to previous case studies by revisiting a set of propositions reported in a 2006 special feature, and 2) reflect on four main ideas that

In this synthesis, we hope to accomplish two things: 1) reflect on how the analysis of the new archaeological cases presented in this special feature adds to previous case studies by revisiting a set of propositions reported in a 2006 special feature, and 2) reflect on four main ideas that are more specific to the archaeological cases: i) societal choices are influenced by robustness–vulnerability trade-offs, ii) there is interplay between robustness–vulnerability trade-offs and robustness–performance trade-offs, iii) societies often get locked in to particular strategies, and iv) multiple positive feedbacks escalate the perceived cost of societal change. We then discuss whether these lock-in traps can be prevented or whether the risks associated with them can be mitigated. We conclude by highlighting how these long-term historical studies can help us to understand current society, societal practices, and the nexus between ecology and society.

ContributorsSchoon, Michael (Author) / Fabricius, Christo (Author) / Anderies, John (Author) / Nelson, Margaret (Author) / College of Liberal Arts and Sciences (Contributor)
Created2011
Description

Photosynthesis, a process catalysed by plants, algae and cyanobacteria converts sunlight to energy thus sustaining all higher life on Earth. Two large membrane protein complexes, photosystem I and II (PSI and PSII), act in series to catalyse the light-driven reactions in photosynthesis. PSII catalyses the light-driven water splitting process, which

Photosynthesis, a process catalysed by plants, algae and cyanobacteria converts sunlight to energy thus sustaining all higher life on Earth. Two large membrane protein complexes, photosystem I and II (PSI and PSII), act in series to catalyse the light-driven reactions in photosynthesis. PSII catalyses the light-driven water splitting process, which maintains the Earth’s oxygenic atmosphere. In this process, the oxygen-evolving complex (OEC) of PSII cycles through five states, S0 to S4, in which four electrons are sequentially extracted from the OEC in four light-driven charge-separation events. Here we describe time resolved experiments on PSII nano/microcrystals from Thermosynechococcus elongatus performed with the recently developed technique of serial femtosecond crystallography. Structures have been determined from PSII in the dark S1 state and after double laser excitation (putative S3 state) at 5 and 5.5 Å resolution, respectively. The results provide evidence that PSII undergoes significant conformational changes at the electron acceptor side and at the Mn4CaO5 core of the OEC. These include an elongation of the metal cluster, accompanied by changes in the protein environment, which could allow for binding of the second substrate water molecule between the more distant protruding Mn (referred to as the ‘dangler’ Mn) and the Mn3CaOx cubane in the S2 to S3 transition, as predicted by spectroscopic and computational studies. This work shows the great potential for time-resolved serial femtosecond crystallography for investigation of catalytic processes in biomolecules.

ContributorsKupitz, Christopher (Author) / Basu, Shibom (Author) / Grotjohann, Ingo (Author) / Fromme, Raimund (Author) / Zatsepin, Nadia (Author) / Rendek, Kimberly (Author) / Hunter, Mark (Author) / Shoeman, Robert L. (Author) / White, Thomas A. (Author) / Wang, Dingjie (Author) / James, Daniel (Author) / Yang, Jay-How (Author) / Cobb, Danielle (Author) / Reeder, Brenda (Author) / Sierra, Raymond G. (Author) / Liu, Haiguang (Author) / Barty, Anton (Author) / Aquila, Andrew L. (Author) / Deponte, Daniel (Author) / Kirian, Richard (Author) / Bari, Sadia (Author) / Bergkamp, Jesse (Author) / Beyerlein, Kenneth R. (Author) / Bogan, Michael J. (Author) / Caleman, Carl (Author) / Chao, Tzu-Chiao (Author) / Conrad, Chelsie (Author) / Davis, Katherine M. (Author) / Department of Chemistry and Biochemistry (Contributor)
Created2014-09-11
Description

We present results from experiments at the Linac Coherent Light Source (LCLS) demonstrating that serial femtosecond crystallography (SFX) can be performed to high resolution (~2.5 Å) using protein microcrystals deposited on an ultra-thin silicon nitride membrane and embedded in a preservation medium at room temperature. Data can be acquired at

We present results from experiments at the Linac Coherent Light Source (LCLS) demonstrating that serial femtosecond crystallography (SFX) can be performed to high resolution (~2.5 Å) using protein microcrystals deposited on an ultra-thin silicon nitride membrane and embedded in a preservation medium at room temperature. Data can be acquired at a high acquisition rate using x-ray free electron laser sources to overcome radiation damage, while sample consumption is dramatically reduced compared to flowing jet methods. We achieved a peak data acquisition rate of 10 Hz with a hit rate of ~38%, indicating that a complete data set could be acquired in about one 12-hour LCLS shift using the setup described here, or in even less time using hardware optimized for fixed target SFX. This demonstration opens the door to ultra low sample consumption SFX using the technique of diffraction-before-destruction on proteins that exist in only small quantities and/or do not produce the copious quantities of microcrystals required for flowing jet methods.

ContributorsHunter, Mark S. (Author) / Segelke, Brent (Author) / Messerschmidt, Marc (Author) / Williams, Garth J. (Author) / Zatsepin, Nadia (Author) / Barty, Anton (Author) / Benner, W. Henry (Author) / Carlson, David B. (Author) / Coleman, Matthew (Author) / Graf, Alexander (Author) / Hau-Riege, Stefan P. (Author) / Pardini, Tommaso (Author) / Seibert, M. Marvin (Author) / Evans, James (Author) / Boutet, Sebastien (Author) / Frank, Matthias (Author) / College of Liberal Arts and Sciences (Contributor)
Created2014-08-12
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Description

In order to improve the efficiency of government spending, it is necessary for the decentralized irrigation management to gain support from local institutions. Efficient institutions take on several distinct configurations in different irrigation districts. In this research, we upgrade Tang’s (1992) framework focusing on incentives, to a framework that includes

In order to improve the efficiency of government spending, it is necessary for the decentralized irrigation management to gain support from local institutions. Efficient institutions take on several distinct configurations in different irrigation districts. In this research, we upgrade Tang’s (1992) framework focusing on incentives, to a framework that includes institutional incentives and coordination. Within the framework, we then classify 5 institutional variables: water pricing reform (P), government funding (F), coordination by administration (C), having formal monitors (M) and self-organized management (S). This article processes the data obtained through a field survey (2009–2011) in 20 of China’s southern counties, where they implement the “Small-scale Irrigation and Water Conservancy Key Counties Construction (Key Counties Construction)”, a national project supported by the central government. Next, it applies Data Envelopment Analysis (DEA) to measure the efficiency of government spending and uses Qualitative Comparative Analysis (QCA) to extract efficient institutional configurations. It concludes that there are generally three types of institutional configurations able to improve the efficiency of government spending, which are respectively: “government funding combined with coordination by administration”, “water pricing reform combined with self-organized management and coordination by administration or water pricing reform combined with self-organized management and government funding and formal monitors” and “self-organized management”. Among these, the second configuration is a mixed governance structure with multiple institutions coexisting, and this configuration occurs in the most efficient key counties. For that reason, it is viewed as the mainstream irrigation management approach, and we expect it to be the development trend in the future. Although Chinese irrigation policies are formalizing effective local institutions, they are still not sufficient. Future policies are needed to 1) promote institutions of government support for water laws in order to build stable expectations for both water user associations (WUAs) and farmers, 2) guide water pricing reform by ensuring farmers’ water rights and regulating water markets, and 3) provide opportunities for hiring professional monitors and crafting formal rules.

Created2016-02-01
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Description

Previous proof-of-concept measurements on single-layer two-dimensional membrane-protein crystals performed at X-ray free-electron lasers (FELs) have demonstrated that the collection of meaningful diffraction patterns, which is not possible at synchrotrons because of radiation-damage issues, is feasible. Here, the results obtained from the analysis of a thousand single-shot, room-temperature X-ray FEL diffraction

Previous proof-of-concept measurements on single-layer two-dimensional membrane-protein crystals performed at X-ray free-electron lasers (FELs) have demonstrated that the collection of meaningful diffraction patterns, which is not possible at synchrotrons because of radiation-damage issues, is feasible. Here, the results obtained from the analysis of a thousand single-shot, room-temperature X-ray FEL diffraction images from two-dimensional crystals of a bacteriorhodopsin mutant are reported in detail. The high redundancy in the measurements boosts the intensity signal-to-noise ratio, so that the values of the diffracted intensities can be reliably determined down to the detector-edge resolution of 4 Å. The results show that two-dimensional serial crystallography at X-ray FELs is a suitable method to study membrane proteins to near-atomic length scales at ambient temperature. The method presented here can be extended to pump–probe studies of optically triggered structural changes on submillisecond timescales in two-dimensional crystals, which allow functionally relevant large-scale motions that may be quenched in three-dimensional crystals.

ContributorsCasadei, Cecilia M. (Author) / Tsai, Ching-Ju (Author) / Barty, Anton (Author) / Hunter, Mark S. (Author) / Zatsepin, Nadia (Author) / Padeste, Celestino (Author) / Capitani, Guido (Author) / Benner, W. Henry (Author) / Boutet, Sebastien (Author) / Hau-Riege, Stefan P. (Author) / Kupitz, Christopher (Author) / Messerschmidt, Marc (Author) / Ogren, John I. (Author) / Pardini, Tom (Author) / Rothschild, Kenneth J. (Author) / Sala, Leonardo (Author) / Segelke, Brent (Author) / Williams, Garth J. (Author) / Evans, James E. (Author) / Li, Xiao-Dan (Author) / Coleman, Matthew (Author) / Pedrini, Bill (Author) / Frank, Matthias (Author) / College of Liberal Arts and Sciences (Contributor)
Created2018-01
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Description

It has been suggested that the extended intensity profiles surrounding Bragg reflections that arise when a series of finite crystals of varying size and shape are illuminated by the intense, coherent illumination of an x-ray free-electron laser may enable the crystal’s unit-cell electron density to be obtained ab initio via

It has been suggested that the extended intensity profiles surrounding Bragg reflections that arise when a series of finite crystals of varying size and shape are illuminated by the intense, coherent illumination of an x-ray free-electron laser may enable the crystal’s unit-cell electron density to be obtained ab initio via well-established iterative phasing algorithms. Such a technique could have a significant impact on the field of biological structure determination since it avoids the need for a priori information from similar known structures, multiple measurements near resonant atomic absorption energies, isomorphic derivative crystals, or atomic-resolution data. Here, we demonstrate this phasing technique on diffraction patterns recorded from artificial two-dimensional microcrystals using the seeded soft x-ray free-electron laser FERMI. We show that the technique is effective when the illuminating wavefront has nonuniform phase and amplitude, and when the diffraction intensities cannot be measured uniformly throughout reciprocal space because of a limited signal-to-noise ratio.

ContributorsKirian, Richard (Author) / Bean, Richard J. (Author) / Beyerlein, Kenneth R. (Author) / Barthelmess, Miriam (Author) / Yoon, Chun Hong (Author) / Wang, Fenglin (Author) / Capotondi, Flavio (Author) / Pedersoli, Emanuele (Author) / Barty, Anton (Author) / Chapman, Henry N. (Author) / College of Liberal Arts and Sciences (Contributor)
Created2015-02-12
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Description

We describe the deposition of four datasets consisting of X-ray diffraction images acquired using serial femtosecond crystallography experiments on microcrystals of human G protein-coupled receptors, grown and delivered in lipidic cubic phase, at the Linac Coherent Light Source. The receptors are: the human serotonin receptor 2B in complex with an

We describe the deposition of four datasets consisting of X-ray diffraction images acquired using serial femtosecond crystallography experiments on microcrystals of human G protein-coupled receptors, grown and delivered in lipidic cubic phase, at the Linac Coherent Light Source. The receptors are: the human serotonin receptor 2B in complex with an agonist ergotamine, the human δ-opioid receptor in complex with a bi-functional peptide ligand DIPP-NH2, the human smoothened receptor in complex with an antagonist cyclopamine, and finally the human angiotensin II type 1 receptor in complex with the selective antagonist ZD7155. All four datasets have been deposited, with minimal processing, in an HDF5-based file format, which can be used directly for crystallographic processing with CrystFEL or other software. We have provided processing scripts and supporting files for recent versions of CrystFEL, which can be used to validate the data.

ContributorsWhite, Thomas A. (Author) / Barty, Anton (Author) / Liu, Wei (Author) / Ishchenko, Andrii (Author) / Zhang, Haitao (Author) / Gati, Cornelius (Author) / Zatsepin, Nadia (Author) / Basu, Shibom (Author) / Oberthur, Dominik (Author) / Metz, Markus (Author) / Beyerlein, Kenneth R. (Author) / Yoon, Chun Hong (Author) / Yefanov, Oleksandr M. (Author) / James, Daniel (Author) / Wang, Dingjie (Author) / Messerschmidt, Marc (Author) / Koglin, Jason E. (Author) / Boutet, Sebastien (Author) / Weierstall, Uwe (Author) / Cherezov, Vadim (Author) / College of Liberal Arts and Sciences (Contributor)
Created2016-08-01
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Description

Structural studies on living cells by conventional methods are limited to low resolution because radiation damage kills cells long before the necessary dose for high resolution can be delivered. X-ray free-electron lasers circumvent this problem by outrunning key damage processes with an ultra-short and extremely bright coherent X-ray pulse. Diffraction-before-destruction

Structural studies on living cells by conventional methods are limited to low resolution because radiation damage kills cells long before the necessary dose for high resolution can be delivered. X-ray free-electron lasers circumvent this problem by outrunning key damage processes with an ultra-short and extremely bright coherent X-ray pulse. Diffraction-before-destruction experiments provide high-resolution data from cells that are alive when the femtosecond X-ray pulse traverses the sample. This paper presents two data sets from micron-sized cyanobacteria obtained at the Linac Coherent Light Source, containing a total of 199,000 diffraction patterns. Utilizing this type of diffraction data will require the development of new analysis methods and algorithms for studying structure and structural variability in large populations of cells and to create abstract models. Such studies will allow us to understand living cells and populations of cells in new ways. New X-ray lasers, like the European XFEL, will produce billions of pulses per day, and could open new areas in structural sciences.

Contributorsvan der Schot, Gijs (Author) / Svenda, Martin (Author) / Maia, Filipe R. N. C. (Author) / Hantke, Max F. (Author) / DePonte, Daniel P. (Author) / Seibert, M. Marvin (Author) / Aquila, Andrew (Author) / Schulz, Joachim (Author) / Kirian, Richard (Author) / Liang, Mengning (Author) / Stellato, Francesco (Author) / Bari, Sadia (Author) / Iwan, Bianca (Author) / Andreasson, Jakob (Author) / Timneanu, Nicusor (Author) / Bielecki, Johan (Author) / Westphal, Daniel (Author) / Nunes de Almeida, Francisca (Author) / Odic, Dusko (Author) / Hasse, Dirk (Author) / Carlsson, Gunilla H. (Author) / Larsson, Daniel S. D. (Author) / Barty, Anton (Author) / Martin, Andrew V. (Author) / Schorb, Sebastian (Author) / Bostedt, Christoph (Author) / Bozek, John D. (Author) / Carron, Sebastian (Author) / Ferguson, Ken (Author) / Rolles, Daniel (Author) / Rudenko, Artem (Author) / Epp, Sascha W. (Author) / Foucar, Lutz (Author) / Rudek, Benedikt (Author) / Erk, Benjamin (Author) / Hartmann, Robert (Author) / Kimmel, Nils (Author) / Holl, Peter (Author) / Englert, Lars (Author) / Loh, N. Duane (Author) / Chapman, Henry N. (Author) / Andersson, Inger (Author) / Hajdu, Janos (Author) / Ekeberg, Tomas (Author) / College of Liberal Arts and Sciences (Contributor)
Created2016-08-01
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Description

A significant challenge of our time is conserving biological diversity while maintaining economic development and cultural values. The United Nations Educational, Scientific and Cultural Organization has established biosphere reserves within its Man and the Biosphere program as a model means for accomplishing this very challenge. The East Carpathians Biosphere Reserve

A significant challenge of our time is conserving biological diversity while maintaining economic development and cultural values. The United Nations Educational, Scientific and Cultural Organization has established biosphere reserves within its Man and the Biosphere program as a model means for accomplishing this very challenge. The East Carpathians Biosphere Reserve (ECBR), spreading across Poland, Slovakia, and Ukraine, represents a large social-ecological system (SES) that has been protected under the biosphere reserve designation since 1998. We have explored its successes and failures in improving human livelihoods while safeguarding its ecosystems. The SES framework, which includes governance system, actors, resources, and external influences, was used as a frame of analysis. The outcomes of this protected area have been mixed; its creation led to national and international collaboration, yet some actor groups remain excluded. Implementation of protocols arising from the Carpathian Convention has been slow, while deforestation, hunting, erosion, temperature extremes, and changes in species behavior remain significant threats but have also been factors in ecological adaptation. The loss of cultural links and traditional knowledge has also been significant. Nevertheless, this remains a highly biodiverse area. Political barriers and institutional blockages will have to be removed to ensure this reserve fulfills its role as a model region for international collaboration and capacity building. These insights drawn from the ECBR demonstrate that biosphere reserves are indeed learning sites for sustainable development and that this case is exemplary in illustrating the challenges, but more importantly, the opportunities that arise when ensuring parallel care and respect for people and ecosystems through the model of transboundary protected areas around the world.

Created2016
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Description

This study explores the capabilities of the Coherent X-ray Imaging Instrument at the Linac Coherent Light Source to image small biological samples. The weak signal from small samples puts a significant demand on the experiment. Aerosolized Omono River virus particles of ∼40 nm in diameter were injected into the submicrometre X-ray

This study explores the capabilities of the Coherent X-ray Imaging Instrument at the Linac Coherent Light Source to image small biological samples. The weak signal from small samples puts a significant demand on the experiment. Aerosolized Omono River virus particles of ∼40 nm in diameter were injected into the submicrometre X-ray focus at a reduced pressure. Diffraction patterns were recorded on two area detectors. The statistical nature of the measurements from many individual particles provided information about the intensity profile of the X-ray beam, phase variations in the wavefront and the size distribution of the injected particles. The results point to a wider than expected size distribution (from ∼35 to ∼300 nm in diameter). This is likely to be owing to nonvolatile contaminants from larger droplets during aerosolization and droplet evaporation. The results suggest that the concentration of nonvolatile contaminants and the ratio between the volumes of the initial droplet and the sample particles is critical in such studies. The maximum beam intensity in the focus was found to be 1.9 × 1012 photons per µm2 per pulse. The full-width of the focus at half-maximum was estimated to be 500 nm (assuming 20% beamline transmission), and this width is larger than expected. Under these conditions, the diffraction signal from a sample-sized particle remained above the average background to a resolution of 4.25 nm. The results suggest that reducing the size of the initial droplets during aerosolization is necessary to bring small particles into the scope of detailed structural studies with X-ray lasers.

ContributorsDaurer, Benedikt J. (Author) / Okamoto, Kenta (Author) / Bielecki, Johan (Author) / Maia, Filipe R. N. C. (Author) / Muhlig, Kerstin (Author) / Seibert, M. Marvin (Author) / Hantke, Max F. (Author) / Nettelblad, Carl (Author) / Benner, W. Henry (Author) / Svenda, Martin (Author) / Timneanu, Nicusor (Author) / Ekeberg, Tomas (Author) / Loh, N. Duane (Author) / Pietrini, Alberto (Author) / Zani, Alessandro (Author) / Rath, Asawari D. (Author) / Westphal, Daniel (Author) / Kirian, Richard (Author) / Awel, Salah (Author) / Wiedorn, Max O. (Author) / van der Schot, Gijs (Author) / Carlsson, Gunilla H. (Author) / Hasse, Dirk (Author) / Sellberg, Jonas A. (Author) / Barty, Anton (Author) / Andreasson, Jakob (Author) / Boutet, Sebastien (Author) / Williams, Garth (Author) / Koglin, Jason (Author) / Andersson, Inger (Author) / Hajdu, Janos (Author) / Larsson, Daniel S. D. (Author) / College of Liberal Arts and Sciences (Contributor)
Created2017-04-07