We report the development of an interactive approach to single-word language production studies in fMRI. The approach, adaptive pacing, involves real-time adjustment of stimulus presentation times ...based on individual subject performance timing and content. At the same time, it maintains a stochastic distribution of interstimulus intervals to avoid confounding task covariates with speech-related signal variance. Adaptive pacing of overt speech production is an example of a new class of paradigms that require an observational approach to data acquisition and benefit from a “time-aware” acquisition and processing environment. The advantages of adaptive pacing in fMRI of impaired subjects are expected to be the acquisition of more informative data per unit time, less contamination of data by correlates of non-language processes such as emotion, and facilitation of experiments that combine normal and impaired subjects.
X-ray free-electron lasers (XFELs) provide very intense X-ray pulses suitable for macromolecular crystallography. Each X-ray pulse typically lasts for tens of femtoseconds and the interval between ...pulses is many orders of magnitude longer. Here we describe two novel acoustic injection systems that use focused sound waves to eject picoliter to nanoliter crystal-containing droplets out of microplates and into the X-ray pulse from which diffraction data are collected. The on-demand droplet delivery is synchronized to the XFEL pulse scheme, resulting in X-ray pulses intersecting up to 88% of the droplets. We tested several types of samples in a range of crystallization conditions, wherein the overall crystal hit ratio (e.g., fraction of images with observable diffraction patterns) is a function of the microcrystal slurry concentration. We report crystal structures from lysozyme, thermolysin, and stachydrine demethylase (Stc2). Additional samples were screened to demonstrate that these methods can be applied to rare samples.
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•Acoustic methods inject crystal-containing droplets directly from microplate wells•On-demand acoustic injection uses crystals efficiently without orifices or clogging•Diffraction patterns from crystals measuring several tens of μm are of high quality•Complete datasets can be obtained from fewer than 50,000 crystals
Acoustic droplet ejection provides an automated tool for efficient use of protein crystals in SFX experiments. Roessler et al. used this method to deliver crystal-containing droplets into the XFEL beam to coincide with each X-ray pulse.
Acoustic liquid handling uses high-frequency acoustic signals that are focused on the surface of a fluid to eject droplets with high accuracy and precision for various life science applications. Here ...we present a multiwell source plate, the Echo Qualified Reservoir (ER), which can acoustically transfer over 2.5 mL of fluid per well in 25-nL increments using an Echo 525 liquid handler. We demonstrate two Labcyte technologies-Dynamic Fluid Analysis (DFA) methods and a high-voltage (HV) grid-that are required to maintain accurate and precise fluid transfers from the ER at this volume scale. DFA methods were employed to dynamically assess the energy requirements of the fluid and adjust the acoustic ejection parameters to maintain a constant velocity droplet. Furthermore, we demonstrate that the HV grid enhances droplet velocity and coalescence at the destination plate. These technologies enabled 5-µL per destination well transfers to a 384-well plate, with accuracy and precision values better than 4%. Last, we used the ER and Echo 525 liquid handler to perform a quantitative polymerase chain reaction (qPCR) assay to demonstrate an application that benefits from the flexibility and larger volume capabilities of the ER.
X-ray free-electron lasers (XFELs) provide very intense X-ray pulses suitable for macromolecular crystallography. Each X-ray pulse typically lasts for tens of femtoseconds and the interval between ...pulses is many orders of magnitude longer. Here we describe two novel acoustic injection systems that use focused sound waves to eject picoliter to nanoliter crystal-containing droplets out of microplates and into the X-ray pulse from which diffraction data are collected. The on-demand droplet delivery is synchronized to the XFEL pulse scheme, resulting in X-ray pulses intersecting up to 88% of the droplets. We tested several types of samples in a range of crystallization conditions, wherein the overall crystal hit ratio (e.g., fraction of images with observable diffraction patterns) is a function of the microcrystal slurry concentration. Lastly, we report crystal structures from lysozyme, thermolysin, and stachydrine demethylase (Stc2). In addition, samples were screened to demonstrate that these methods can be applied to rare samples
Model assessment and model building in fMRI Razavi, Mehrdad; Grabowski, Thomas J.; Vispoel, Walter P. ...
Human brain mapping,
December 2003, Letnik:
20, Številka:
4
Journal Article
Trade and the Global Recession Eaton, Jonathan; Kortum, Samuel; Neiman, Brent ...
The American economic review,
11/2016, Letnik:
106, Številka:
11
Journal Article
Recenzirano
Odprti dostop
We develop a dynamic multicountry general equilibrium model to investigate forces acting on the global economy during the Great Recession and ensuing recovery. Our multisector framework accounts ...completely for countries' trade, investment, production, and GDPs in terms of different sets of shocks. Applying the model to 21 countries, we investigate the 29 percent drop in world trade in manufactures during the period 2008-2009. A shift in final spending away from tradable sectors, largely caused by declines in durables investment efficiency, accounts for most of the collapse in trade relative to GDP. Shocks to trade frictions, productivity, and demand play minor roles.
Anisotropic colloidal quasi-two-dimensional nanoplates (NPLs) hold great promise as functional materials due to their combination of low dimensional optoelectronic properties and versatility through ...colloidal synthesis. Recently, lead-halide perovskites have emerged as important optoelectronic materials with excellent efficiencies in photovoltaic and light-emitting applications. Here we report the synthesis of quantum confined all inorganic cesium lead halide nanoplates in the perovskite crystal structure that are also highly luminescent (PLQY 84%). The controllable self-assembly of nanoplates either into stacked columnar phases or crystallographic-oriented thin-sheet structures is demonstrated. The broad accessible emission range, high native quantum yields, and ease of self-assembly make perovskite NPLs an ideal platform for fundamental optoelectronic studies and the investigation of future devices.
Wastewater-based epidemiology (WBE) is rapidly developing as a powerful public health tool. It can provide information about a wide range of health determinants (HDs), including community exposure to ...environmental hazards, trends in consumption of licit and illicit substances, spread of infectious diseases, and general community health. As such, the list of possible candidate HDs for WBE is almost limitless. Consequently, a means to evaluate and prioritize suitable candidates for WBE is useful, particularly for public health authorities, who often face resource constraints.
We have developed a framework to assist public health authorities to decide what HDs may be appropriate for WBE and what biomarkers could be used. This commentary reflects the experience of the authors, who work at the interface of research and public health implementation.
To be suitable for WBE, a candidate HD should address a public health or scientific issue that would benefit from better understanding at the population level. For HDs where information on individual exposures or stratification by population subgroups is required, WBE is less suitable. Where other methodologies are already used to monitor the candidate HD, consideration must be given to whether WBE could provide better or complementary information to the current approach. An essential requirement of WBE is a biomarker specific for the candidate HD. A biomarker in this context refers to any human-excreted chemical or biological that could act as an indicator of consumption or exposure to an environmental hazard or of the human health state. Suitable biomarkers should meet several criteria outlined in this commentary, which requires background knowledge for both the biomarker and the HD. An evaluation tree summarizing key considerations for public health authorities when assessing the suitability of candidate HDs for WBE and an example evaluation are presented. https://doi.org/10.1289/EHP11115.
Celotno besedilo
Dostopno za:
CEKLJ, DOBA, IZUM, KILJ, NUK, OILJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK, VSZLJ
Obstfeld and Rogoff (2001) propose that trade frictions lie behind key puzzles in international macroeconomics. We take a dynamic multicountry model of international trade, production, and investment ...to data from 19 countries to assess this proposition quantitatively. Using the framework developed in Eaton et al. (2016), we revisit the puzzles in a counterfactual world without trade frictions in manufactures. Removing these trade frictions goes a long way toward resolving a number of puzzles. The dependence of domestic investment on domestic saving falls by half or disappears entirely, mitigating the Feldstein and Horioka (1980) puzzle. Changes in nominal GDPs in U.S. dollars become less variable across countries and line up with changes in real GDPs as much as with real exchange rates, mitigating the exchange rate disconnect puzzle. Less dramatically, changes in consumption become more correlated across countries, mitigating the consumption correlations puzzle and changes in real exchange rates become less variable across countries, mitigating the relative purchasing power parity puzzle.
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