Sample records for optical initiation doi
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Laser-based firing systems for prompt initiation of secondary explosives
NASA Technical Reports Server (NTRS)
Meeks, Kent D.; Setchell, Robert E.
1993-01-01
Motivated by issues of weapon safety and security, laser based firing systems for promptly initiating secondary explosives have been under active development at Sandia National Laboratories for more than four years. Such a firing system consists of miniaturized, Q-switched, solid-state laser, optical detonators, optical safety switches, and elements for splitting, coupling, and transmitting the laser output. Potential system applications pose significant challenges in terms of server mechanical and thermal environments and packaging constraints, while requiring clear demonstration of safety enhancements. The Direct Optical Initiation (DOI) Program at Sandia is addressing these challenges through progress development phases during which the design, fabrication, and testing of prototype hardware is aimed at more difficult application requirements. A brief history of the development program, and a summary of current and planned activities, will be presented.
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Threshold thickness for applying diffusion equation in thin tissue optical imaging
NASA Astrophysics Data System (ADS)
Zhang, Yunyao; Zhu, Jingping; Cui, Weiwen; Nie, Wei; Li, Jie; Xu, Zhenghong
2014-08-01
We investigated the suitability of the semi-infinite model of the diffusion equation when using diffuse optical imaging (DOI) to image thin tissues with double boundaries. Both diffuse approximation and Monte Carlo methods were applied to simulate light propagation in the thin tissue model with variable optical parameters and tissue thicknesses. A threshold value of the tissue thickness was defined as the minimum thickness in which the semi-infinite model exhibits the same reflected intensity as that from the double-boundary model and was generated as the final result. In contrast to our initial hypothesis that all optical properties would affect the threshold thickness, our results show that only absorption coefficient is the dominant parameter and the others are negligible. The threshold thickness decreases from 1 cm to 4 mm as the absorption coefficient grows from 0.01 mm-1 to 0.2 mm-1. A look-up curve was derived to guide the selection of the appropriate model during the optical diagnosis of thin tissue cancers. These results are useful in guiding the development of the endoscopic DOI for esophageal, cervical and colorectal cancers, among others.
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Detonator Performance Characterization Using Multi-Frame Laser Schlieren Imaging
NASA Astrophysics Data System (ADS)
Clarke, S. A.; Landon, C. D.; Murphy, M. J.; Martinez, M. E.; Mason, T. A.; Thomas, K. A.
2009-12-01
Several experiments that are part of a phased plan to understand the evolution of detonation in a detonator from initiation shock through run to detonation to full detonation to transition to booster and booster detonation will be presented. High speed laser schlieren movies have been used to study several explosive initiation events, such as exploding bridgewires (EBW), exploding foil initiators (EFI) (or slappers), direct optical initiation (DOI), and electrostatic discharge (ESD). Additionally, a series of tests have been performed on "cut-back" detonators with varying initial pressing (IP) heights. We have also used this diagnostic to visualize a range of EBW, EFI, and DOI full-up detonators. Future applications to other explosive events such as boosters and IHE booster evaluation will be discussed. The EPIC hydrodynamic code has been used to analyze the shock fronts from the schlieren images to reverse calculate likely boundary or initial conditions to determine the temporal-spatial pressure profile across the output face of the detonator. LA-UR-05099
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Using Schlieren Visualization to Track Detonator Performance
NASA Astrophysics Data System (ADS)
Clarke, S. A.; Bolme, C. A.; Murphy, M. J.; Landon, C. D.; Mason, T. A.; Adrian, R. J.; Akinci, A. A.; Martinez, M. E.; Thomas, K. A.
2007-12-01
Several experiments will be presented that are part of a phased plan to understand the evolution of detonation in a detonator from initiation shock through run to detonation, to full detonation, to transition, to booster and booster detonation. High-speed multiframe schlieren imagery has been used to study several explosive initiation events, such as exploding bridgewires (EBWs), exploding foil initiators (EFIs or "slappers"), direct optical initiation (DOI), and electrostatic discharge. Additionally, a series of tests has been performed on "cut-back" detonators with varying initial pressing heights. We have also used this diagnostic to visualize a range of EBW, EFI, and DOI full-up detonators. Future applications to other explosive events, such as boosters and insensitive high explosives booster evaluation, will be discussed. The EPIC finite element code has been used to analyze the shock fronts from the schlieren images to solve iteratively for consistent boundary or initial conditions to determine the temporal-spatial pressure profile across the output face of the detonator.
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Using Schlieren Visualization to Track Detonator Performance
NASA Astrophysics Data System (ADS)
Clarke, Steven; Thomas, Keith; Martinez, Michael; Akinci, Adrian; Murphy, Michael; Adrian, Ronald
2007-06-01
Several experiments that are part of a phased plan to understand the evolution of detonation in a detonator from initiation shock through run to detonation to full detonation to transition to booster and booster detonation will be presented. High Speed Laser Schlieren Movies have been used to study several explosive initiation events, such as exploding bridgewires (EBW), Exploding Foil Initiators (EFI) (or slappers), Direct Optical Initiation (DOI), and ElectroStatic Discharge (ESD). Additionally, a series of tests have been performed on ``cut-back'' detonators with varying initial pressing (IP) heights. We have also used this diagnostic to visualize a range of EBW, EFI, and DOI full-up detonators. Future applications to other explosive events such as boosters and IHE booster evaluation will be discussed. EPIC Hydrodynamic code has been used to analyze the shock fronts from the Schlieren images to reverse calculate likely boundary or initial conditions to determine the temporal-spatial pressure profile across the output face of the detonator. LA-UR-07-1229
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Alayed, Mrwan; Deen, M Jamal
2017-09-14
Diffuse optical spectroscopy (DOS) and diffuse optical imaging (DOI) are emerging non-invasive imaging modalities that have wide spread potential applications in many fields, particularly for structural and functional imaging in medicine. In this article, we review time-resolved diffuse optical imaging (TR-DOI) systems using solid-state detectors with a special focus on Single-Photon Avalanche Diodes (SPADs) and Silicon Photomultipliers (SiPMs). These TR-DOI systems can be categorized into two types based on the operation mode of the detector (free-running or time-gated). For the TR-DOI prototypes, the physical concepts, main components, figures-of-merit of detectors, and evaluation parameters are described. The performance of TR-DOI prototypes is evaluated according to the parameters used in common protocols to test DOI systems particularly basic instrumental performance (BIP). In addition, the potential features of SPADs and SiPMs to improve TR-DOI systems and expand their applications in the foreseeable future are discussed. Lastly, research challenges and future developments for TR-DOI are discussed for each component in the prototype separately and also for the entire system.
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Alayed, Mrwan
2017-01-01
Diffuse optical spectroscopy (DOS) and diffuse optical imaging (DOI) are emerging non-invasive imaging modalities that have wide spread potential applications in many fields, particularly for structural and functional imaging in medicine. In this article, we review time-resolved diffuse optical imaging (TR-DOI) systems using solid-state detectors with a special focus on Single-Photon Avalanche Diodes (SPADs) and Silicon Photomultipliers (SiPMs). These TR-DOI systems can be categorized into two types based on the operation mode of the detector (free-running or time-gated). For the TR-DOI prototypes, the physical concepts, main components, figures-of-merit of detectors, and evaluation parameters are described. The performance of TR-DOI prototypes is evaluated according to the parameters used in common protocols to test DOI systems particularly basic instrumental performance (BIP). In addition, the potential features of SPADs and SiPMs to improve TR-DOI systems and expand their applications in the foreseeable future are discussed. Lastly, research challenges and future developments for TR-DOI are discussed for each component in the prototype separately and also for the entire system. PMID:28906462
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Depth-of-interaction estimates in pixelated scintillator sensors using Monte Carlo techniques
NASA Astrophysics Data System (ADS)
Sharma, Diksha; Sze, Christina; Bhandari, Harish; Nagarkar, Vivek; Badano, Aldo
2017-01-01
Image quality in thick scintillator detectors can be improved by minimizing parallax errors through depth-of-interaction (DOI) estimation. A novel sensor for low-energy single photon imaging having a thick, transparent, crystalline pixelated micro-columnar CsI:Tl scintillator structure has been described, with possible future application in small-animal single photon emission computed tomography (SPECT) imaging when using thicker structures under development. In order to understand the fundamental limits of this new structure, we introduce cartesianDETECT2, an open-source optical transport package that uses Monte Carlo methods to obtain estimates of DOI for improving spatial resolution of nuclear imaging applications. Optical photon paths are calculated as a function of varying simulation parameters such as columnar surface roughness, bulk, and top-surface absorption. We use scanning electron microscope images to estimate appropriate surface roughness coefficients. Simulation results are analyzed to model and establish patterns between DOI and photon scattering. The effect of varying starting locations of optical photons on the spatial response is studied. Bulk and top-surface absorption fractions were varied to investigate their effect on spatial response as a function of DOI. We investigated the accuracy of our DOI estimation model for a particular screen with various training and testing sets, and for all cases the percent error between the estimated and actual DOI over the majority of the detector thickness was ±5% with a maximum error of up to ±10% at deeper DOIs. In addition, we found that cartesianDETECT2 is computationally five times more efficient than MANTIS. Findings indicate that DOI estimates can be extracted from a double-Gaussian model of the detector response. We observed that our model predicts DOI in pixelated scintillator detectors reasonably well.
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Yamamoto, Seiichi
2013-07-01
The silicon photomultiplier (Si-PM) is a promising photodetector for PET. However, it remains unclear whether Si-PM can be used for a depth-of-interaction (DOI) detector based on the decay time differences of the scintillator where pulse shape analysis is used. For clarification, we tested the Hamamatsu 4 × 4 Si-PM array (S11065-025P) combined with scintillators that used different decay times to develop DOI block detectors using the pulse shape analysis. First, Ce-doped Gd(2)SiO(5) (GSO) scintillators of 0.5 mol% Ce were arranged in a 4 × 4 matrix and were optically coupled to the center of each pixel of the Si-PM array for measurement of the energy resolution as well as its gain variations according to the temperature. Then two types of Ce-doped Lu(1.9)Gd(0.1)Si0(5) (LGSO) scintillators, 0.025 mol% Ce (decay time: ~31 ns) and 0.75 mol% Ce (decay time: ~46 ns), were optically coupled in the DOI direction, arranged in a 11 × 7 matrix, and optically coupled to a Si-PM array for testing of the possibility of a high-resolution DOI detector. The energy resolution of the Si-PM array-based GSO block detector was 18 ± 4.4 % FWHM for a Cs-137 gamma source (662 keV). Less than 1 mm crystals were clearly resolved in the position map of the LGSO DOI block detector. The peak-to-valley ratio (P/V) derived from the pulse shape spectra of the LGSO DOI block detector was 2.2. These results confirmed that Si-PM array-based DOI block detectors are promising for high-resolution small animal PET systems.
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High-speed multi-frame laser Schlieren for visualization of explosive events
NASA Astrophysics Data System (ADS)
Clarke, S. A.; Murphy, M. J.; Landon, C. D.; Mason, T. A.; Adrian, R. J.; Akinci, A. A.; Martinez, M. E.; Thomas, K. A.
2007-09-01
High-Speed Multi-Frame Laser Schlieren is used for visualization of a range of explosive and non-explosive events. Schlieren is a well-known technique for visualizing shock phenomena in transparent media. Laser backlighting and a framing camera allow for Schlieren images with very short (down to 5 ns) exposure times, band pass filtering to block out explosive self-light, and 14 frames of a single explosive event. This diagnostic has been applied to several explosive initiation events, such as exploding bridgewires (EBW), Exploding Foil Initiators (EFI) (or slappers), Direct Optical Initiation (DOI), and ElectroStatic Discharge (ESD). Additionally, a series of tests have been performed on "cut-back" detonators with varying initial pressing (IP) heights. We have also used this Diagnostic to visualize a range of EBW, EFI, and DOI full-up detonators. The setup has also been used to visualize a range of other explosive events, such as explosively driven metal shock experiments and explosively driven microjets. Future applications to other explosive events such as boosters and IHE booster evaluation will be discussed. Finite element codes (EPIC, CTH) have been used to analyze the schlieren images to determine likely boundary or initial conditions to determine the temporal-spatial pressure profile across the output face of the detonator. These experiments are part of a phased plan to understand the evolution of detonation in a detonator from initiation shock through run to detonation to full detonation to transition to booster and booster detonation.
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Uchida, H; Sakai, T; Yamauchi, H; Hakamata, K; Shimizu, K; Yamashita, T
2016-09-21
We propose a novel scintillation detector design for positron emission tomography (PET), which has depth of interaction (DOI) capability and uses a single-ended readout scheme. The DOI detector contains a pair of crystal bars segmented using sub-surface laser engraving (SSLE). The two crystal bars are optically coupled to each other at their top segments and are coupled to two photo-sensors at their bottom segments. Initially, we evaluated the performance of different designs of single crystal bars coupled to photomultiplier tubes at both ends. We found that segmentation by SSLE results in superior performance compared to the conventional method. As the next step, we constructed a crystal unit composed of a 3 × 3 × 20 mm 3 crystal bar pair, with each bar containing four layers segmented using the SSLE. We measured the DOI performance by changing the optical conditions for the crystal unit. Based on the experimental results, we then assessed the detector performance in terms of the DOI capability by evaluating the position error, energy resolution, and light collection efficiency for various crystal unit designs with different bar sizes and a different number of layers (four to seven layers). DOI encoding with small position error was achieved for crystal units composed of a 3 × 3 × 20 mm 3 LYSO bar pair having up to seven layers, and with those composed of a 2 × 2 × 20 mm 3 LYSO bar pair having up to six layers. The energy resolution of the segment in the seven-layer 3 × 3 × 20 mm 3 crystal bar pair was 9.3%-15.5% for 662 keV gamma-rays, where the segments closer to the photo-sensors provided better energy resolution. SSLE provides high geometrical accuracy at low production cost due to the simplicity of the crystal assembly. Therefore, the proposed DOI detector is expected to be an attractive choice for practical small-bore PET systems dedicated to imaging of the brain, breast, and small animals.
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NASA Astrophysics Data System (ADS)
Mohammadi, Akram; Inadama, Naoko; Yoshida, Eiji; Nishikido, Fumihiko; Shimizu, Keiji; Yamaya, Taiga
2017-09-01
We have developed a four-layer depth of interaction (DOI) detector with single-side photon readout, in which segmented crystals with the patterned reflector insertion are separately identified by the Anger-type calculation. Optical conditions between segmented crystals, where there is no reflector, affect crystal identification ability. Our objective of this work was to improve crystal identification performance of the four-layer DOI detector that uses crystals segmented with a recently developed laser processing technique to include laser processed boundaries (LPBs). The detector consisted of 2 × 2 × 4mm3 LYSO crystals and a 4 × 4 array multianode photomultiplier tube (PMT) with 4.5 mm anode pitch. The 2D position map of the detector was calculated by the Anger calculation method. At first, influence of optical condition on crystal identification was evaluated for a one-layer detector consisting of a 2 × 2 crystal array with three different optical conditions between the crystals: crystals stuck together using room temperature vulcanized (RTV) rubber, crystals with air coupling and segmented crystals with LPBs. The crystal array with LPBs gave the shortest distance between crystal responses in the 2D position map compared with the crystal array coupled with RTV rubber or air due to the great amount of cross-talk between segmented crystals with LPBs. These results were used to find optical conditions offering the optimum distance between crystal responses in the 2D position map for the four-layer DOI detector. Crystal identification performance for the four-layer DOI detector consisting of an 8 × 8 array of crystals segmented with LPBs was examined and it was not acceptable for the crystals in the first layer. The crystal identification was improved for the first layer by changing the optical conditions between all 2 × 2 crystal arrays of the first layer to RTV coupling. More improvement was observed by combining different optical conditions between all crystals of the first layer and some crystals of the second and the third layers of the segmented array.
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Detonator Performance Characterization using Multi-Frame Laser Schlieren Imaging
NASA Astrophysics Data System (ADS)
Clarke, Steven; Landon, Colin; Murphy, Michael; Martinez, Michael; Mason, Thomas; Thomas, Keith
2009-06-01
Multi-frame Laser Schlieren Imaging of shock waves produced by detonators in transparent witness materials can be used to evaluate detonator performance. We use inverse calculations of the 2D propagation of shock waves in the EPIC finite element model computer code to calculate a temporal-spatial-pressure profile on the surface of the detonator that is consistent with the experimental shock waves from the schlieren imaging. Examples of calculated 2D temporal-spatial-pressure profiles from a range of detonator types (EFI --exploding foil initiators, DOI -- direct optical initiation, EBW -- exploding bridge wire, hotwire), detonator HE materials (PETN, HMX, etc), and HE densities. Also pressure interaction profiles from the interaction of multiple shock waves will be shown. LA-UR-09-00909.
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Measuring In-Plane Displacements with Variable Sensitivity Using Diffractive Optic Interferometry
NASA Technical Reports Server (NTRS)
Shepherd, Robert L.; Gilbert, John A.; Cole, Helen J.; Ashley, Paul R.
1998-01-01
This paper introduces a method called diffractive optic interferometry (DOI) which allows in-plane displacement components to be measured with variable sensitivity. DOI relies on binary optical elements fabricated as phase-type Dammann gratings which produce multiple diffraction orders of nearly equal intensity. Sensitivity is varied by combining the different wavefronts produced by a conjugate pair of these binary optical elements; a transmission element is used to produce several illumination beams while a reflective element, replicated on the surface of a specimen, provides the reference for the undeformed state. The steps taken to design and fabricate these binary optical elements are described. The specimen grating is characterized, and tested on a disk subjected to diametrical compression. Overall, the results are excellent, with experimental data agreeing to within a few percent of the theoretical predictions.
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Collins, Kevin M; Bode, Addys; Fernandez, Robert W; Tanis, Jessica E; Brewer, Jacob C; Creamer, Matthew S; Koelle, Michael R
2016-01-01
Like many behaviors, Caenorhabditis elegans egg laying alternates between inactive and active states. To understand how the underlying neural circuit turns the behavior on and off, we optically recorded circuit activity in behaving animals while manipulating circuit function using mutations, optogenetics, and drugs. In the active state, the circuit shows rhythmic activity phased with the body bends of locomotion. The serotonergic HSN command neurons initiate the active state, but accumulation of unlaid eggs also promotes the active state independent of the HSNs. The cholinergic VC motor neurons slow locomotion during egg-laying muscle contraction and egg release. The uv1 neuroendocrine cells mechanically sense passage of eggs through the vulva and release tyramine to inhibit egg laying, in part via the LGC-55 tyramine-gated Cl- channel on the HSNs. Our results identify discrete signals that entrain or detach the circuit from the locomotion central pattern generator to produce active and inactive states. DOI: http://dx.doi.org/10.7554/eLife.21126.001 PMID:27849154
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Sequence-dependent base pair stepping dynamics in XPD helicase unwinding
Qi, Zhi; Pugh, Robert A; Spies, Maria; Chemla, Yann R
2013-01-01
Helicases couple the chemical energy of ATP hydrolysis to directional translocation along nucleic acids and transient duplex separation. Understanding helicase mechanism requires that the basic physicochemical process of base pair separation be understood. This necessitates monitoring helicase activity directly, at high spatio-temporal resolution. Using optical tweezers with single base pair (bp) resolution, we analyzed DNA unwinding by XPD helicase, a Superfamily 2 (SF2) DNA helicase involved in DNA repair and transcription initiation. We show that monomeric XPD unwinds duplex DNA in 1-bp steps, yet exhibits frequent backsteps and undergoes conformational transitions manifested in 5-bp backward and forward steps. Quantifying the sequence dependence of XPD stepping dynamics with near base pair resolution, we provide the strongest and most direct evidence thus far that forward, single-base pair stepping of a helicase utilizes the spontaneous opening of the duplex. The proposed unwinding mechanism may be a universal feature of DNA helicases that move along DNA phosphodiester backbones. DOI: http://dx.doi.org/10.7554/eLife.00334.001 PMID:23741615
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43 CFR 45.25 - What will DOI do with any hearing requests?
Code of Federal Regulations, 2010 CFR
2010-10-01
... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false What will DOI do with any hearing requests... PRESCRIPTIONS IN FERC HYDROPOWER LICENSES Hearing Process Initiation of Hearing Process § 45.25 What will DOI do... will refer the case for a hearing as follows: (1) If the hearing is to be conducted by DOI, OEPC will...
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43 CFR 45.25 - What will DOI do with any hearing requests?
Code of Federal Regulations, 2011 CFR
2011-10-01
... 43 Public Lands: Interior 1 2011-10-01 2011-10-01 false What will DOI do with any hearing requests... PRESCRIPTIONS IN FERC HYDROPOWER LICENSES Hearing Process Initiation of Hearing Process § 45.25 What will DOI do... will refer the case for a hearing as follows: (1) If the hearing is to be conducted by DOI, OEPC will...
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43 CFR 17.333 - Investigation.
Code of Federal Regulations, 2010 CFR
2010-10-01
..., Conciliation, and Enforcement Procedures § 17.333 Investigation. (a) Informal investigation. (1) DOI will... mediation agreement. (2) As part of the initial investigation, DOI will use informal fact finding methods... possible, settle the complaint on terms that are mutually agreeable to the parties. DOI may seek the...
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43 CFR 17.333 - Investigation.
Code of Federal Regulations, 2011 CFR
2011-10-01
..., Conciliation, and Enforcement Procedures § 17.333 Investigation. (a) Informal investigation. (1) DOI will... mediation agreement. (2) As part of the initial investigation, DOI will use informal fact finding methods... possible, settle the complaint on terms that are mutually agreeable to the parties. DOI may seek the...
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Airflow and optic flow mediate antennal positioning in flying honeybees
Roy Khurana, Taruni; Sane, Sanjay P
2016-01-01
To maintain their speeds during navigation, insects rely on feedback from their visual and mechanosensory modalities. Although optic flow plays an essential role in speed determination, it is less reliable under conditions of low light or sparse landmarks. Under such conditions, insects rely on feedback from antennal mechanosensors but it is not clear how these inputs combine to elicit flight-related antennal behaviours. We here show that antennal movements of the honeybee, Apis mellifera, are governed by combined visual and antennal mechanosensory inputs. Frontal airflow, as experienced during forward flight, causes antennae to actively move forward as a sigmoidal function of absolute airspeed values. However, corresponding front-to-back optic flow causes antennae to move backward, as a linear function of relative optic flow, opposite the airspeed response. When combined, these inputs maintain antennal position in a state of dynamic equilibrium. DOI: http://dx.doi.org/10.7554/eLife.14449.001 PMID:27097104
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Brain activation and connectivity of social cognition using diffuse optical imaging
NASA Astrophysics Data System (ADS)
Zhu, Banghe; Godavarty, Anuradha
2009-02-01
In the current research, diffuse optical imaging (DOI) is used for the first time towards studies related to sociocommunication impairments, which is a characteristic feature of autism. DOI studies were performed on normal adult volunteers to determine the differences in the brain activation (cognitive regions) in terms of the changes in the cerebral blood oxygenation levels in response to joint and non-joint attention based stimulus (i.e. socio-communicative paradigms shown as video clips). Functional connectivity models are employed to assess the extent of synchronization between the left and right pre-frontal regions of the brain in response to the above stimuli.
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Assessing the future of diffuse optical imaging technologies for breast cancer management
Tromberg, Bruce J.; Pogue, Brian W.; Paulsen, Keith D.; Yodh, Arjun G.; Boas, David A.; Cerussi, Albert E.
2008-01-01
Diffuse optical imaging (DOI) is a noninvasive optical technique that employs near-infrared (NIR) light to quantitatively characterize the optical properties of thick tissues. Although NIR methods were first applied to breast transillumination (also called diaphanography) nearly 80 years ago, quantitative DOI methods employing time- or frequency-domain photon migration technologies have only recently been used for breast imaging (i.e., since the mid-1990s). In this review, the state of the art in DOI for breast cancer is outlined and a multi-institutional Network for Translational Research in Optical Imaging (NTROI) is described, which has been formed by the National Cancer Institute to advance diffuse optical spectroscopy and imaging (DOSI) for the purpose of improving breast cancer detection and clinical management. DOSI employs broadband technology both in near-infrared spectral and temporal signal domains in order to separate absorption from scattering and quantify uptake of multiple molecular probes based on absorption or fluorescence contrast. Additional dimensionality in the data is provided by integrating and co-registering the functional information of DOSI with x-ray mammography and magnetic resonance imaging (MRI), which provide structural information or vascular flow information, respectively. Factors affecting DOSI performance, such as intrinsic and extrinsic contrast mechanisms, quantitation of biochemical components, image formation∕visualization, and multimodality co-registration are under investigation in the ongoing research NTROI sites. One of the goals is to develop standardized DOSI platforms that can be used as stand-alone devices or in conjunction with MRI, mammography, or ultrasound. This broad-based, multidisciplinary effort is expected to provide new insight regarding the origins of breast disease and practical approaches for addressing several key challenges in breast cancer, including: Detecting disease in mammographically dense tissue, distinguishing between malignant and benign lesions, and understanding the impact of neoadjuvant chemotherapies. PMID:18649477
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Innovation Diffusion Model in Higher Education: Case Study of E-Learning Diffusion
ERIC Educational Resources Information Center
Buc, Sanjana; Divjak, Blaženka
2015-01-01
The diffusion of innovation (DOI) is critical for any organization and especially nowadays for higher education institutions (HEIs) in the light of vast pressure of emerging educational technologies as well as of the demand of economy and society. DOI takes into account the initial and the implementation phase. The conceptual model of DOI in…
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Heermann, Stephan; Schütz, Lucas; Lemke, Steffen; Krieglstein, Kerstin; Wittbrodt, Joachim
2015-01-01
The hemispheric, bi-layered optic cup forms from an oval optic vesicle during early vertebrate eye development through major morphological transformations. The overall basal surface, facing the developing lens, is increasing, while, at the same time, the space basally occupied by individual cells is decreasing. This cannot be explained by the classical view of eye development. Using zebrafish (Danio rerio) as a model, we show that the lens-averted epithelium functions as a reservoir that contributes to the growing neuroretina through epithelial flow around the distal rims of the optic cup. We propose that this flow couples morphogenesis and retinal determination. Our 4D data indicate that future stem cells flow from their origin in the lens-averted domain of the optic vesicle to their destination in the ciliary marginal zone. BMP-mediated inhibition of the flow results in ectopic neuroretina in the RPE domain. Ultimately the ventral fissure fails to close resulting in coloboma. DOI: http://dx.doi.org/10.7554/eLife.05216.001 PMID:25719386
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PECASE: Resonantly-Enhanced Lanthanide Emitters for Subwavelength-Scale, Active Photonics
2015-03-19
2013), 191109, DOI:10.1063/1.4829142. [12] Dongfang Li, Nabil M. Lawandy, and Rashid Zia, “Surface phonon- polariton enhanced optical forces in...10.1063/1.4829142. [12] Dongfang Li, Nabil M. Lawandy, and Rashid Zia, “Surface phonon- polariton enhanced optical forces in silicon carbide
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Quantum Phases of Matter in Optical Lattices
2015-06-30
doi: 10.1103/PhysRevA.89.013625 Hyungwon Kim, David A. Huse. Ballistic Spreading of Entanglement in a Diffusive Nonintegrable System, Physical...Review B, (07 2013): 0. doi: 10.1103/PhysRevB.88.014206 Lin Dong, Lei Jiang, Han Pu. Fulde–Ferrell pairing instability in spin–orbit coupled Fermi...PhysRevA.87.051603 Kuei Sun, C. J. Bolech. Pair tunneling, phase separation, and dimensional crossover in imbalanced fermionic superfluids in a coupled
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2015-11-03
scale optical projection system powered by spatial light modulators, such as digital micro-mirror device ( DMD ). Figure 4 shows the parallel lithography ...1Scientific RepoRts | 5:16192 | DOi: 10.1038/srep16192 www.nature.com/scientificreports High throughput optical lithography by scanning a massive...array of bowtie aperture antennas at near-field X. Wen1,2,3,*, A. Datta1,*, L. M. Traverso1, L. Pan1, X. Xu1 & E. E. Moon4 Optical lithography , the
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Noninvasive diffusive optical imaging of the auditory response to birdsong in the zebra finch
Lee, James V.; Maclin, Edward L.; Low, Kathy A.; Gratton, Gabriele; Fabiani, Monica; Clayton, David F.
2013-01-01
Songbirds communicate by learned vocalizations with concomitant changes in neurophysiological and genomic activities in discrete parts of the brain. Here we tested a novel implementation of diffusive optical imaging (also known as diffuse optical imaging, DOI) for monitoring brain physiology associated with vocal signal perception. DOI noninvasively measures brain activity using red and near-infrared light delivered through optic fibers (optodes) resting on the scalp. DOI does not harm subjects, so it raises the possibility of repeatedly measuring brain activity and the effects of accumulated experience in the same subject over an entire life span, all while leaving tissue intact for further study. We developed a custom-made apparatus for interfacing optodes to the zebra finch (Taeniopygia guttata) head using 3D modeling software and rapid prototyping technology, and applied it to record responses to presentations of birdsong in isoflurane-anesthetized zebra finches. We discovered a subtle but significant difference between the hemoglobin spectra of zebra finches and mammals which has a major impact in how hemodynamic responses are interpreted in the zebra finch. Our measured responses to birdsong playback were robust, highly repeatable, and readily observed in single trials. Responses were complex in shape and closely paralleled responses described in mammals. They were localized to the caudal medial portion of the brain, consistent with response localization from prior gene expression, electrophysiological, and functional magnetic resonance imaging studies. These results define an approach for collecting neurophysiological data from songbirds that should be applicable to diverse species and adaptable for studies in awake behaving animals. PMID:23322445
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Sidhaye, Jaydeep; Norden, Caren
2017-01-01
Organ formation is a multi-scale event that involves changes at the intracellular, cellular and tissue level. Organogenesis often starts with the formation of characteristically shaped organ precursors. However, the cellular mechanisms driving organ precursor formation are often not clear. Here, using zebrafish, we investigate the epithelial rearrangements responsible for the development of the hemispherical retinal neuroepithelium (RNE), a part of the optic cup. We show that in addition to basal shrinkage of RNE cells, active migration of connected epithelial cells into the RNE is a crucial player in its formation. This cellular movement is driven by progressive cell-matrix contacts and actively translocates prospective RNE cells to their correct location before they adopt neuroepithelial fate. Failure of this migration during neuroepithelium formation leads to ectopic determination of RNE cells and consequently impairs optic cup formation. Overall, this study illustrates how spatiotemporal coordination between morphogenic movements and fate determination critically influences organogenesis. DOI: http://dx.doi.org/10.7554/eLife.22689.001 PMID:28372636
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Optogenetic feedback control of neural activity
Newman, Jonathan P; Fong, Ming-fai; Millard, Daniel C; Whitmire, Clarissa J; Stanley, Garrett B; Potter, Steve M
2015-01-01
Optogenetic techniques enable precise excitation and inhibition of firing in specified neuronal populations and artifact-free recording of firing activity. Several studies have suggested that optical stimulation provides the precision and dynamic range requisite for closed-loop neuronal control, but no approach yet permits feedback control of neuronal firing. Here we present the ‘optoclamp’, a feedback control technology that provides continuous, real-time adjustments of bidirectional optical stimulation in order to lock spiking activity at specified targets over timescales ranging from seconds to days. We demonstrate how this system can be used to decouple neuronal firing levels from ongoing changes in network excitability due to multi-hour periods of glutamatergic or GABAergic neurotransmission blockade in vitro as well as impinging vibrissal sensory drive in vivo. This technology enables continuous, precise optical control of firing in neuronal populations in order to disentangle causally related variables of circuit activation in a physiologically and ethologically relevant manner. DOI: http://dx.doi.org/10.7554/eLife.07192.001 PMID:26140329
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2013-04-30
Syst., 40, 171-212. doi:10.1016/S0924-7963(03)00018-6. Cane, M. A., A. Kaplan, R. N. Miller, B. Tang , E. Hackcrt, and A. J. Busalacchi (1996...Fluoromctric determination of chlorophyll, J. Cons. Cons. Int. Explor. Mer.,30,3-\\5. Hu, J., K. Fennel, J. P. Mattcrn, and J. Wilkin (2012), Data
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Cryogenic Optical Refrigeration
2012-03-22
Applications of Laser Cooling of Solids, 1st ed. (Wiley-VCH, 2009). 12. M. Sheik- Bahae and R. I . Epstein, “Optical refrigeration,” Nat. Photonics 1(12), 693–699...2007). Advances in Optics and Photonics 4, 78–107 (2012) doi:10.1364/AOP.4.000078 99 13. M. Sheik- Bahae and R. I . Epstein, “Laser cooling of solids...Sheik- Bahae and R. I . Epstein, “Can laser light cool semiconductors,” Phys. Rev. Lett. 92(24), 247403 (2004). 18. P. Asbeck, “Self-absorption effects
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Mode-Selective Amplification in a Large Mode Area Yb-Doped Fiber Using a Photonic Lantern
2016-05-15
in a few mode, double- clad Yb-doped large mode area (LMA) fiber, utilizing an all-fiber photonic lantern. Amplification to multi-watt output power is...that could enable dynamic spatial mode control in high power fiber lasers . © 2016 Optical Society of America OCIS codes: (060.2320) Fiber optics...amplifiers and oscillators; (060.2340) Fiber optics components. http://dx.doi.org/10.1364/OL.41.002157 The impressive growth experienced by fiber lasers and
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A compilation of global bio-optical in situ data for ocean-colour satellite applications
NASA Astrophysics Data System (ADS)
Valente, André; Sathyendranath, Shubha; Brotas, Vanda; Groom, Steve; Grant, Michael; Taberner, Malcolm; Antoine, David; Arnone, Robert; Balch, William M.; Barker, Kathryn; Barlow, Ray; Bélanger, Simon; Berthon, Jean-François; Beşiktepe, Şükrü; Brando, Vittorio; Canuti, Elisabetta; Chavez, Francisco; Claustre, Hervé; Crout, Richard; Frouin, Robert; García-Soto, Carlos; Gibb, Stuart W.; Gould, Richard; Hooker, Stanford; Kahru, Mati; Klein, Holger; Kratzer, Susanne; Loisel, Hubert; McKee, David; Mitchell, Brian G.; Moisan, Tiffany; Muller-Karger, Frank; O'Dowd, Leonie; Ondrusek, Michael; Poulton, Alex J.; Repecaud, Michel; Smyth, Timothy; Sosik, Heidi M.; Twardowski, Michael; Voss, Kenneth; Werdell, Jeremy; Wernand, Marcel; Zibordi, Giuseppe
2016-06-01
A compiled set of in situ data is important to evaluate the quality of ocean-colour satellite-data records. Here we describe the data compiled for the validation of the ocean-colour products from the ESA Ocean Colour Climate Change Initiative (OC-CCI). The data were acquired from several sources (MOBY, BOUSSOLE, AERONET-OC, SeaBASS, NOMAD, MERMAID, AMT, ICES, HOT, GeP&CO), span between 1997 and 2012, and have a global distribution. Observations of the following variables were compiled: spectral remote-sensing reflectances, concentrations of chlorophyll a, spectral inherent optical properties and spectral diffuse attenuation coefficients. The data were from multi-project archives acquired via the open internet services or from individual projects, acquired directly from data providers. Methodologies were implemented for homogenisation, quality control and merging of all data. No changes were made to the original data, other than averaging of observations that were close in time and space, elimination of some points after quality control and conversion to a standard format. The final result is a merged table designed for validation of satellite-derived ocean-colour products and available in text format. Metadata of each in situ measurement (original source, cruise or experiment, principal investigator) were preserved throughout the work and made available in the final table. Using all the data in a validation exercise increases the number of matchups and enhances the representativeness of different marine regimes. By making available the metadata, it is also possible to analyse each set of data separately. The compiled data are available at doi:10.1594/PANGAEA.854832 (Valente et al., 2015).
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NASA Astrophysics Data System (ADS)
Wang, D.; Takagi, N.
2012-12-01
We have observed the lightning occurred on a 100 m high windmill and its 105 m high standalone lightning-protection tower about 45 m separated from the windmill in the Hokuriku area of Japan for 7 consecutive winter seasons from 2005 to 2012. Our main observation items include: (1) Lightning current at the bottom of both the windmill and the tower. (2) Thunderstorm electric fields and the electric field changes caused by lightning at multiple sites. (3) Optical images by both low and high speed imaging systems. During the 7 winter seasons, over 100 lightning have hit either the tower or the windmill or both. All the lightning but two observed are of upward lightning. Those upward lightning can be sub-classified into self-initiated types and other-triggered types according to whether there is a discharge activity prior to the upward leaders or not. Self-initiated and other-triggered upward lightning tend to have biased percentages in terms of striking locations (windmill versus tower) and thunderstorm types (active versus weak). All the upward lightning but one contained only initial continuous current stages. In the presentation, we will first give a review on those results we have reported before [1-3]. As an update, we will report the following results. (1) The electric field change required for triggering a negative upward leader is usually more than twice bigger than that for triggering a positive upward leader. (2) An electric current pulse with an amplitude of several tens of Amperes along a high structure has been observed to occur in response to a rapid electric change generated by either a nearby return stroke or K-change. References [1] D.Wang, N.Takagi, T.Watanebe, H. Sakurano, M. Hashimoto, Observed characteristics of upward leaders that are initiated from a windmill and its lightning protection tower, Geophys. Res. Lett., Vol.35, L02803, doi:10.1029/2007GL032136, 2008. [2] W. Lu, D.Wang, Y. Zhang and N. Takagi, Two associated upward lightning flashes that produced opposite polarity electric field changes, Geophys. Res. Lett., Vol.36, L05801, doi:10.1029/2008GL036598, 2009. [3] D. Wang, N. Takagi, Characteristics of Winter Lightning that Occurred on a Windmill and its Lightning Protection Tower in Japan, IEEJ Trans. on Power and Energy, Vol. 132, No.6, pp.568-572, Doi:10.1541/ieejpes.132.568, 2012.
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NASA Astrophysics Data System (ADS)
Wang, Jinhai; Liu, Dongyuan; Sun, Jinggong; Zhang, Yanjun; Sun, Qiuming; Ma, Jun; Zheng, Yu; Wang, Huiquan
2016-10-01
Near-infrared (NIR) brain imaging is one of the most promising techniques for brain research in recent years. As a significant supplement to the clinical imaging technique, such as CT and MRI, the NIR technique can achieve a fast, non-invasive, and low cost imaging of the brain, which is widely used for the brain functional imaging and hematoma detection. NIR imaging can achieve an imaging depth up to only several centimeters due to the reduced optical attenuation. The structure of the human brain is so particularly complex, from the perspective of optical detection, the measurement light needs go through the skin, skull, cerebrospinal fluid (CSF), grey matter, and white matter, and then reverses the order reflected by the detector. The more photons from the Depth of Interest (DOI) in brain the detector capture, the better detection accuracy and stability can be obtained. In this study, the Equivalent Signal to Noise Ratio (ESNR) was defined as the proportion of the photons from the DOI to the total photons the detector evaluated the best Source and Detector (SD) separation. The Monte-Carlo (MC) simulation was used to establish a multi brain layer model to analyze the distribution of the ESNR along the radial direction for different DOIs and several basic brain optical and structure parameters. A map between the best detection SD separation, in which distance the ESNR was the highest, and the brain parameters was established for choosing the best detection point in the NIR brain imaging application. The results showed that the ESNR was very sensitivity to the SD separation. So choosing the best SD separation based on the ESNR is very significant for NIR brain imaging application. It provides an important reference and new thinking for the brain imaging in the near infrared.
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Terahertz Response of a Microfabricated Rod Split-Ring-Resonator Electromagnetic Metamaterial
NASA Astrophysics Data System (ADS)
Moser, H. O.; Casse, B. D.; Wilhelmi, O.; Saw, B. T.
2005-02-01
The first electromagnetic metamaterials (EM3) produced by microfabrication are reported. They are based on the rod split-ring-resonator design as proposed by Pendry et al. [
IEEE Trans. Microwave Theory Tech. 47, 2075 (1999) ] and experimentally confirmed by Smith et al. [IETMAB 0018-9480 10.1109/22.798002 Phys. Rev. Lett. ] in the GHz frequency range. Numerical simulation and experimental results from far infrared (FIR) transmission spectroscopy support the conclusion that the microfabricated composite material is EM3 in the range 1 2.7 THz. This extends the frequency range in which EM3 are available by about 3 orders of magnitude well into the FIR, thereby widely opening up opportunities to verify the unusual physical implications on electromagnetic theory as well as to build novel electromagnetic and optical devices.PRLTAO 0031-9007 84, 4184 (2000)10.1103/PhysRevLett.84.4184 -
A tunable refractive index matching medium for live imaging cells, tissues and model organisms
Boothe, Tobias; Hilbert, Lennart; Heide, Michael; Berninger, Lea; Huttner, Wieland B; Zaburdaev, Vasily; Vastenhouw, Nadine L; Myers, Eugene W; Drechsel, David N; Rink, Jochen C
2017-01-01
In light microscopy, refractive index mismatches between media and sample cause spherical aberrations that often limit penetration depth and resolution. Optical clearing techniques can alleviate these mismatches, but they are so far limited to fixed samples. We present Iodixanol as a non-toxic medium supplement that allows refractive index matching in live specimens and thus substantially improves image quality in live-imaged primary cell cultures, planarians, zebrafish and human cerebral organoids. DOI: http://dx.doi.org/10.7554/eLife.27240.001 PMID:28708059
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Effect of Mars Atmospheric Loss on Snow Melt Potential in a 3.5 Gyr Mars Climate Evolution Model
NASA Astrophysics Data System (ADS)
Mansfield, Megan; Kite, Edwin S.; Mischna, Michael A.
2018-04-01
Post-Noachian Martian paleochannels indicate the existence of liquid water on the surface of Mars after about 3.5 Gya (Irwin et al., 2015, https://doi.org/10.1016/j.geomorph.2014.10.012; Palucis et al., 2016, https://doi.org/10.1002/2015JE004905). In order to explore the effects of variations in CO2 partial pressure and obliquity on the possibility of surface water, we created a zero-dimensional surface energy balance model. We combine this model with physically consistent orbital histories to track conditions over the last 3.5 Gyr of Martian history. We find that melting is allowed for atmospheric pressures corresponding to exponential loss rates of dP/dt∝t-3.73 or faster, but this rate is within 0.5σ of the rate calculated from initial measurements made by the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission, if we assume all the escaping oxygen measured by MAVEN comes from atmospheric CO2 (Lillis et al., 2017, https://doi.org/10.1002/2016JA023525; Tu et al., 2015, https://doi.org/10.1051/0004-6361/201526146). Melting at this loss rate matches selected key geologic constraints on the formation of Hesperian river networks, assuming optimal melt conditions during the warmest part of each Mars year (Irwin et al., 2015, https://doi.org/10.1016/j.geomorph.2014.10.012; Kite, Gao, et al., 2017, https://doi.org/10.1038/ngeo3033; Kite, Sneed et al., 2017, https://doi.org/10.1002/2017GL072660; Stopar et al., 2006, https://doi.org/10.1016/j.gca.2006.07.039). The atmospheric pressure has a larger effect on the surface energy than changes in Mars's mean obliquity. These results show that initial measurements of atmosphere loss by MAVEN are consistent with atmospheric loss being the dominant process that switched Mars from a melt-permitting to a melt-absent climate (Jakosky et al., 2017, https://doi.org/10.1126/science.aai7721), but non-CO2 warming will be required if <2 Gya paleochannels are confirmed or if most of the escaping oxygen measured by MAVEN comes from H2O.
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NASA Astrophysics Data System (ADS)
Sahoo, N. K.; Tokas, R. B.; Thakur, S.
2006-12-01
This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief. This article has been retracted as Figures 2, 3, 6b, 7a, 7b, 8a and 8b duplicate figures from the article that was published by the authors in Applied Optics 45 (2006) 3243-3252, https://doi.org/10.1364/AO.45.003243. Also the article duplicates parts of the text of the articles that were published by the authors in Applied Optics 45 (2006) 3243-3252, https://doi.org/10.1364/AO.45.003243 and Applied Surface Science 253 (2006) 618-626, http://dx.doi.org/10.1016/j.apsusc.2005.12.148. One of the conditions of submission of a paper for publication is that authors declare explicitly that their work is original and has not appeared in a publication elsewhere. Re-use of any data should be appropriately cited. As such this article represents an abuse of the scientific publishing system. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process.
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Yamamoto, Seiichi
2012-01-01
In block detectors for PET scanners that use different lengths of slits in scintillators to share light among photomultiplier tubes (PMTs), a position histogram is distorted when the depth of interaction (DOI) of the gamma photons is near the PMTs (DOI effect). However, it remains unclear whether a DOI effect is observed for block detectors that use light sharing in scintillators. To investigate the effect, I tested the effect for single- and dual-layer block detectors. In the single-layer block detector, Ce doped Gd₂SiO₅ (GSO) crystals of 1.9 × 1.9 × 15 mm³ (0.5 mol% Ce) were used. In the dual-layer block detector, GSO crystals of a 1.9 × 1.9 × 6 mm³ (1.5 mol% Ce) were used for the front layer and GSO crystals of 1.9 × 1.9 × 9 mm³ (0.5 mol% Ce) for the back layer. These scintillators were arranged to form an 8 × 8 matrix with multi-layer optical film inserted partly between the scintillators for obtaining an optimized position response with use of two dual-PMTs. Position histograms and energy responses were measured for these block detectors at three different DOI positions, and the flood histograms were obtained. The results indicated that DOI effects are observed in both block detectors, but the dual-layer block showed more severe distortion in the position histogram as well as larger energy variations. We conclude that, in the block detectors that use light sharing in the scintillators, the DOI effect is an important factor for the performance of the detectors, especially for DOI block detectors.
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NASA Astrophysics Data System (ADS)
Jethva, H. T.; Torres, O.; Waquet, F.; Chand, D.
2013-12-01
Atmospheric aerosols are known to produce a net cooling effect in the cloud-free conditions. However, when present over the reflective cloud decks, absorbing aerosols such as biomass burning generated smoke and wind-blown dust can potentially exert a large positive forcing through enhanced atmospheric heating resulting from cloud-aerosol radiative interactions. The interest on this aspect of aerosol science has grown significantly in the recent years. Particularly, development of the satellite-based retrieval techniques and unprecedented knowledge on the above-cloud aerosol optical depth (ACAOD) is of great relevance. A direct validation of satellite ACAOD is a difficult task primarily due to lack of ample in situ and/or remote sensing measurements of aerosols above cloud. In these circumstances, a comparative analysis on the inter-satellite ACAOD retrievals can be performed for the sack of consistency check. Here, we inter-compare the ACAOD of biomass burning plumes observed from different A-train sensors, i.e., MODIS [Jethva et al., 2013], CALIOP [Chand et al., 2008], POLDER [Waquet et al., 2009], and OMI [Torres et al., 2012]. These sensors have been shown to acquire sensitivity and independent capabilities to detect and retrieve aerosol loading above marine stratocumulus clouds--a kind of situation often found over the southeastern Atlantic Ocean during dry burning season. A systematic one-to-one comparison reveals that, in general, all passive sensors and CALIOP-based research methods retrieve comparable ACAOD over homogeneous cloud fields. The high-resolution sensors (MODIS and CALIOP) are able to retrieve aerosols over thin clouds but with larger discrepancies. Given the different types of sensor measurements processed with different algorithms, a reasonable agreement between them is encouraging. A direct validation of satellite-based ACAOD remains an open challenge for which dedicated field measurements over the region of frequent aerosol/cloud overlap are a prime requirement. Jethva, H., O. Torres, L. A. Remer, P. K. Bhartia (2013), A Color Ratio Method for Simultaneous Retrieval of Aerosol and Cloud Optical Thickness of Above-Cloud Absorbing Aerosols From Passive Sensors: Application to MODIS Measurements, Geoscience and Remote Sensing, IEEE Transactions on, 51(7), pp. 3862-3870, doi: 10.1109/TGRS.2012.2230008. Chand, D., T. L. Anderson, R. Wood, R. J. Charlson, Y. Hu, Z. Liu, and M. Vaughan (2008), Quantifying above-cloud aerosol using spaceborne lidar for improved understanding of cloudy-sky direct climate forcing, J. Geophys. Res., 113, D13206, doi:10.1029/2007JD009433. Waquet, F., J. Riedi, L. C. Labonnote, P. Goloub, B. Cairns, J.-L. Deuzeand, and D. Tanre (2009), Aerosol remote sensing over clouds using a-train observations, J. Atmos. Sci., 66(8), 2468-2480, doi: http://dx.doi.org/10.1175/2009JAS3026.1 Torres, O., H. Jethva, and P. K. Bhartia (2012), Retrieval of aerosol optical depth above clouds from OMI observations: Sensitivity analysis and case studies, J. Atmos. Sci., 69(3), 1037-1053, doi: http://dx.doi.org/10.1175/JAS-D-11-0130.
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A novel method to calibrate DOI function of a PET detector with a dual-ended-scintillator readout.
Shao, Yiping; Yao, Rutao; Ma, Tianyu
2008-12-01
The detection of depth-of-interaction (DOI) is a critical detector capability to improve the PET spatial resolution uniformity across the field-of-view and will significantly enhance, in particular, small bore system performance for brain, breast, and small animal imaging. One promising technique of DOI detection is to use dual-ended-scintillator readout that uses two photon sensors to detect scintillation light from both ends of a scintillator array and estimate DOI based on the ratio of signals (similar to Anger logic). This approach needs a careful DOI function calibration to establish accurate relationship between DOI and signal ratios, and to recalibrate if the detection condition is shifted due to the drift of sensor gain, bias variations, or degraded optical coupling, etc. However, the current calibration method that uses coincident events to locate interaction positions inside a single scintillator crystal has severe drawbacks, such as complicated setup, long and repetitive measurements, and being prone to errors from various possible misalignments among the source and detector components. This method is also not practically suitable to calibrate multiple DOI functions of a crystal array. To solve these problems, a new method has been developed that requires only a uniform flood source to irradiate a crystal array without the need to locate the interaction positions, and calculates DOI functions based solely on the uniform probability distribution of interactions over DOI positions without knowledge or assumption of detector responses. Simulation and experiment have been studied to validate the new method, and the results show that the new method, with a simple setup and one single measurement, can provide consistent and accurate DOI functions for the entire array of multiple scintillator crystals. This will enable an accurate, simple, and practical DOI function calibration for the PET detectors based on the design of dual-ended-scintillator readout. In addition, the new method can be generally applied to calibrating other types of detectors that use the similar dual-ended readout to acquire the radiation interaction position.
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A novel method to calibrate DOI function of a PET detector with a dual-ended-scintillator readout
DOE Office of Scientific and Technical Information (OSTI.GOV)
Shao Yiping; Yao Rutao; Ma Tianyu
The detection of depth-of-interaction (DOI) is a critical detector capability to improve the PET spatial resolution uniformity across the field-of-view and will significantly enhance, in particular, small bore system performance for brain, breast, and small animal imaging. One promising technique of DOI detection is to use dual-ended-scintillator readout that uses two photon sensors to detect scintillation light from both ends of a scintillator array and estimate DOI based on the ratio of signals (similar to Anger logic). This approach needs a careful DOI function calibration to establish accurate relationship between DOI and signal ratios, and to recalibrate if the detectionmore » condition is shifted due to the drift of sensor gain, bias variations, or degraded optical coupling, etc. However, the current calibration method that uses coincident events to locate interaction positions inside a single scintillator crystal has severe drawbacks, such as complicated setup, long and repetitive measurements, and being prone to errors from various possible misalignments among the source and detector components. This method is also not practically suitable to calibrate multiple DOI functions of a crystal array. To solve these problems, a new method has been developed that requires only a uniform flood source to irradiate a crystal array without the need to locate the interaction positions, and calculates DOI functions based solely on the uniform probability distribution of interactions over DOI positions without knowledge or assumption of detector responses. Simulation and experiment have been studied to validate the new method, and the results show that the new method, with a simple setup and one single measurement, can provide consistent and accurate DOI functions for the entire array of multiple scintillator crystals. This will enable an accurate, simple, and practical DOI function calibration for the PET detectors based on the design of dual-ended-scintillator readout. In addition, the new method can be generally applied to calibrating other types of detectors that use the similar dual-ended readout to acquire the radiation interaction position.« less
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New Directions in the Detection of Polarized Light
2011-01-01
vision and draws from anatomical and behavioural studies as well as optics . Horvath et al. [3] polish this and the whole volume off with a fascinating...example of biomimicry . It is important to recognize that all work presented in this special issue has grown from the inspirational efforts of our...atmospheric optical prerequisites allowing polarimetric navigation by Viking seafarers. Phil. Trans. R. Soc. B 366, 772–782. (doi:10.1098/rstb.2010.0194) 4
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Advanced Optical Fibers for High power Fiber lasers
2015-08-24
crystal fiber cladding . Advanced Optical Fibers for High Power Fiber Lasers http://dx.doi.org/10.5772/58958 223 lengths above the second-order mode cut...brightness multimode diode lasers for a given pump waveguide dimen‐ sion. In conventional double- clad fibers, low-index polymer coatings are typically used to...was below 0.2. The fiber was passive and there was no laser demonstration in this first attempt. The first cladding - pumping demonstration in an
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ERIC Educational Resources Information Center
van Nassau, Femke; Singh, Amika S.; van Mechelen, Willem; Brug, Johannes; Chin A. Paw, Mai J. M.
2014-01-01
Background: The school-based Dutch Obesity Intervention in Teenagers (DOiT) program is an evidence-based obesity prevention program. In preparation for dissemination throughout the Netherlands, this study aimed to adapt the initial program and to develop an implementation strategy and materials. Methods: We revisited the Intervention Mapping (IM)…
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NASA Astrophysics Data System (ADS)
Kobayashi, Takahiro; Yamamoto, Seiichi; Yeom, Jung-Yeol; Kamada, Kei; Yoshikawa, Akira
2017-12-01
To correct for parallax error in positron emission tomography (PET), phoswich depth-of-interaction (DOI) detector using multiple scintillators with different decay times is a practical approach. However not many scintillator combinations suitable for phoswich DOI detector have been reported. Ce doped Gd3Ga3Al2O12 (GFAG) is a newly developed promising scintillator for PET detector, which has high density, high light output, appropriate light emission wavelength for silicon-photomultiplier (Si-PM) and faster decay time than that of Ce doped Gd3Al2Ga3O12 (GAGG). In this study, we developed a Si-PM based phoswich DOI block detector of GFAG with GAGG crystal arrays and evaluated its performance. We assembled a GFAG block and a GAGG block and they were optically coupled in depth direction to form a phoswich detector block. The phoswich block was optically coupled to a Si-PM array with a 1 mm thick light guide. The sizes of the GFAG and GAGG pixels were 0.9 mm x 0.9 mm x 7.5 mm and they were arranged into 24 x 24 matrix with 0.1 mm thick BaSO4 as reflector. We conducted the performance evaluation for two types of configurations; GFAG block arranged in upper layer (GFAG/GAGG) and GAGG arranged in upper layer (GAGG/GFAG). The measured two dimensional position histograms of these block detectors showed good separation and pulse shape spectra produced two distinct peaks for both configurations although some difference in energy spectra were observed. These results indicate phoswich block detectors composed of GFAG and GAGG are promising for high resolution DOI PET systems.
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Multimodal Diffuse Optical Imaging
NASA Astrophysics Data System (ADS)
Intes, Xavier; Venugopal, Vivek; Chen, Jin; Azar, Fred S.
Diffuse optical imaging, particularly diffuse optical tomography (DOT), is an emerging clinical modality capable of providing unique functional information, at a relatively low cost, and with nonionizing radiation. Multimodal diffuse optical imaging has enabled a synergistic combination of functional and anatomical information: the quality of DOT reconstructions has been significantly improved by incorporating the structural information derived by the combined anatomical modality. In this chapter, we will review the basic principles of diffuse optical imaging, including instrumentation and reconstruction algorithm design. We will also discuss the approaches for multimodal imaging strategies that integrate DOI with clinically established modalities. The merit of the multimodal imaging approaches is demonstrated in the context of optical mammography, but the techniques described herein can be translated to other clinical scenarios such as brain functional imaging or muscle functional imaging.
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Perspectives from the Aldo Leopold Wilderness Research Institute: Amphibians and wilderness
Corn, Paul Stephen
2001-01-01
The decline of amphibian species has emerged as a major global conservation issue in the last decade. Last year, the Department of the Interior (DOI) initiated a major national initiative to detect trends in amphibian populations and research the causes of declines. The program, conducted principally by the U.S. Geological Survey (USGS), emphasizes lands managed by DOI, but collaboration with the Forest Service is encouraged to increase the scope of inference about population trends. Although amphibians are not usually the first group of animals that comes to mind when one thinks of wilderness, conservation of amphibian populations is clearly a wilderness issue.
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Three-Dimensional Displacement Measurement Using Diffractive Optic Interferometry
NASA Technical Reports Server (NTRS)
Gilbert, John A.; Cole, Helen J.; Shepherd, Robert L.; Ashley Paul R.
1999-01-01
This paper introduces a powerful new optical method which utilizes diffractive optic interferometry (DOI) to measure both in-plane and out-of-plane displacement with variable sensitivity using the same optical system. Sensitivity is varied by utilizing various combinations of the different wavefronts produced by a conjugate pair of binary Optical elements; a transmission grating is used to produce several illumination beams while a reflective grating replicated on the surface of a specimen, provides the reference for the undeformed state. A derivation of the equations which govern the method is included along with a discussion Of the experimental tests conducted to verify the theory. Overall, the results are excellent, with experimental data agreeing to within a few percent of the theoretical predictions.
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Selectively driving cholinergic fibers optically in the thalamic reticular nucleus promotes sleep
Ni, Kun-Ming; Hou, Xiao-Jun; Yang, Ci-Hang; Dong, Ping; Li, Yue; Zhang, Ying; Jiang, Ping; Berg, Darwin K; Duan, Shumin; Li, Xiao-Ming
2016-01-01
Cholinergic projections from the basal forebrain and brainstem are thought to play important roles in rapid eye movement (REM) sleep and arousal. Using transgenic mice in which channelrhdopsin-2 is selectively expressed in cholinergic neurons, we show that optical stimulation of cholinergic inputs to the thalamic reticular nucleus (TRN) activates local GABAergic neurons to promote sleep and protect non-rapid eye movement (NREM) sleep. It does not affect REM sleep. Instead, direct activation of cholinergic input to the TRN shortens the time to sleep onset and generates spindle oscillations that correlate with NREM sleep. It does so by evoking excitatory postsynaptic currents via α7-containing nicotinic acetylcholine receptors and inducing bursts of action potentials in local GABAergic neurons. These findings stand in sharp contrast to previous reports of cholinergic activity driving arousal. Our results provide new insight into the mechanisms controlling sleep. DOI: http://dx.doi.org/10.7554/eLife.10382.001 PMID:26880556
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Single-molecule fluorimetry and gating currents inspire an improved optical voltage indicator
Treger, Jeremy S; Priest, Michael F; Bezanilla, Francisco
2015-01-01
Voltage-sensing domains (VSDs) underlie the movement of voltage-gated ion channels, as well as the voltage-sensitive fluorescent responses observed from a common class of genetically encoded voltage indicators (GEVIs). Despite the widespread use and potential utility of these GEVIs, the biophysical underpinnings of the relationship between VSD movement and fluorophore response remain unclear. We investigated the recently developed GEVI ArcLight, and its close variant Arclight', at both the single-molecule and macroscopic levels to better understand their characteristics and mechanisms of activity. These studies revealed a number of previously unobserved features of ArcLight's behavior, including millisecond-scale fluorescence fluctuations in single molecules as well as a previously unreported delay prior to macroscopic fluorescence onset. Finally, these mechanistic insights allowed us to improve the optical response of ArcLight to fast or repetitive pulses with the development of ArcLightning, a novel GEVI with improved kinetics. DOI: http://dx.doi.org/10.7554/eLife.10482.001 PMID:26599732
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Complementary mechanisms create direction selectivity in the fly
Haag, Juergen; Arenz, Alexander; Serbe, Etienne; Gabbiani, Fabrizio; Borst, Alexander
2016-01-01
How neurons become sensitive to the direction of visual motion represents a classic example of neural computation. Two alternative mechanisms have been discussed in the literature so far: preferred direction enhancement, by which responses are amplified when stimuli move along the preferred direction of the cell, and null direction suppression, where one signal inhibits the response to the subsequent one when stimuli move along the opposite, i.e. null direction. Along the processing chain in the Drosophila optic lobe, directional responses first appear in T4 and T5 cells. Visually stimulating sequences of individual columns in the optic lobe with a telescope while recording from single T4 neurons, we find both mechanisms at work implemented in different sub-regions of the receptive field. This finding explains the high degree of directional selectivity found already in the fly’s primary motion-sensing neurons and marks an important step in our understanding of elementary motion detection. DOI: http://dx.doi.org/10.7554/eLife.17421.001 PMID:27502554
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Modeling landslide runout dynamics and hazards: crucial effects of initial conditions
NASA Astrophysics Data System (ADS)
Iverson, R. M.; George, D. L.
2016-12-01
Physically based numerical models can provide useful tools for forecasting landslide runout and associated hazards, but only if the models employ initial conditions and parameter values that faithfully represent the states of geological materials on slopes. Many models assume that a landslide begins from a heap of granular material poised on a slope and held in check by an imaginary dam. A computer instruction instantaneously removes the dam, unleashing a modeled landslide that accelerates under the influence of a large force imbalance. Thus, an unrealistically large initial acceleration influences all subsequent modeled motion. By contrast, most natural landslides are triggered by small perturbations of statically balanced effective stress states, which are commonly caused by rainfall, snowmelt, or earthquakes. Landslide motion begins with an infinitesimal force imbalance and commensurately small acceleration. However, a small initial force imbalance can evolve into a much larger imbalance if feedback causes a reduction in resisting forces. A well-documented source of such feedback involves dilatancy coupled to pore-pressure evolution, which may either increase or decrease effective Coulomb friction—contingent on initial conditions. Landslide dynamics models that account for this feedback include our D-Claw model (Proc. Roy. Soc. Lon., Ser. A, 2014, doi: 10.1098/rspa.2013.0819 and doi:10.1098/rspa.2013.0820) and a similar model presented by Bouchut et al. (J. Fluid Mech., 2016, doi:10.1017/jfm.2016.417). We illustrate the crucial effects of initial conditions and dilatancy coupled to pore-pressure feedback by using D-Claw to perform simple test calculations and also by computing alternative behaviors of the well-documented Oso, Washington, and West Salt Creek, Colorado, landslides of 2014. We conclude that realistic initial conditions and feedbacks are essential elements in numerical models used to forecast landslide runout dynamics and hazards.
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Membrane Reflector Vertical Cavity Lasers at Near- and Midwave-Infrared
2014-05-30
independent broadband reflectors based on cross-stacked gratings, Optics Express, (04 2011): 9050. doi: 10.1364/OE.19.009050 Tapas Kumar Saha, Mingyu Lu... Mingyu Lu, Huiqing Zhai, Deyin Zhao, Weidong Zhou. Design of a compact grating coupler with controllable linewidths via transverse resonance and
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NASA Astrophysics Data System (ADS)
Bojowald, Martin
The universe, ultimately, is to be described by quantum theory. Quantum aspects of all there is, including space and time, may not be significant for many purposes, but are crucial for some. And so a quantum description of cosmology is required for a complete and consistent worldview. At any rate, even if we were not directly interested in regimes where quantum cosmology plays a role, a complete physical description could not stop at a stage before the whole universe is reached. Quantum theory is essential in the microphysics of particles, atoms, molecules, solids, white dwarfs and neutron stars. Why should one expect this ladder of scales to end at a certain size? If regimes are sufficiently violent and energetic, quantum effects are non-negligible even on scales of the whole cosmos; this is realized at least once in the history of the universe: at the big bang where the classical theory of general relativity would make energy densities diverge.
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Simulation and Micro-Fabrication of Optically Switchable Split Ring Resonators
2007-01-01
Simulation and micro-fabrication of optically switchable split ring resonators T.F. Gundogdu a,*, Mutlu Gökkavas b, Kaan Güven b, M. Kafesaki a...mail address: tamara@iesl.forth.gr (T.F. Gundogdu ). 1569-4410/$ – see front matter # 2007 Published by Elsevier B.V. doi:10.1016/j.photonics...ABSTRACT unclassified c. THIS PAGE unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 T.F. Gundogdu et al. / Photonics and
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Optical Computations for Image Bandwidth Compression.
1981-05-15
UnCl1 ed 3 ’ " * ~ SECURITY CLASSIFICA/ION OF TWIS PA E Doi&e, be,. Enteerdj’ . /j (I) RFRORT DOCUMENTATION PAGE EAPINSTRUCTIONS (I) ~tOT DCUMETATON...Bolling Air Force Base, D. C. 20332 . NME’/PG 14. MONITORING AGENCY NAME 8 AOORESS(/I dilletnt from Controlling Office) IS. SECURITY CLASS. (oI thi ,(il... SECURITY CL.ASS4FICATII_ TI.AGE(W7Ief Deja Entered)2 (3)25imulations.m f a!1 incoherent optical/ *1 video feedback processor.. * Unclassi fled
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NASA Technical Reports Server (NTRS)
Root, Ralph; Wickland, Diane
2001-01-01
In 1997 the Office of Biological Informatics and Outreach (OBIO), Biological Resources Division, US Geological Survey and NASA, Office of Earth Science (OES), initiated a coordinated effort for applying Airborne Visible and Infrared Imaging Spectrometer (AVIRIS) data and analysis, as a technology transfer project, to critical DOI environmental issues in four study sites throughout the United States. This work was accomplished by four US Department of the Interior (DOI) study teams with support from NASA/OES principal investigators and the Office of Earth Science programs. The studies, including personnel, objectives, background, project plans, and milestones were documented in a project website at
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Parker, Andrew M; Bruine de Bruin, Wändi; Fischhoff, Baruch
2015-01-01
Most behavioral decision research takes place in carefully controlled laboratory settings, and examination of relationships between performance and specific real-world decision outcomes is rare. One prior study shows that people who perform better on hypothetical decision tasks, assessed using the Adult Decision-Making Competence (A-DMC) measure, also tend to experience better real-world decision outcomes, as reported on the Decision Outcomes Inventory (DOI). The DOI score reflects avoidance of outcomes that could result from poor decisions, ranging from serious (e.g., bankruptcy) to minor (e.g., blisters from sunburn). The present analyses go beyond the initial work, which focused on the overall DOI score, by analyzing the relationships between specific decision outcomes and A-DMC performance. Most outcomes are significantly more likely among people with lower A-DMC scores, even after taking into account two variables expected to produce worse real-world decision outcomes: younger age and lower socio-economic status. We discuss the usefulness of DOI as a measure of successful real-world decision-making.
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Nucleosomes influence multiple steps during replication initiation
Azmi, Ishara F; Watanabe, Shinya; Maloney, Michael F; Kang, Sukhyun; Belsky, Jason A; MacAlpine, David M; Peterson, Craig L; Bell, Stephen P
2017-01-01
Eukaryotic replication origin licensing, activation and timing are influenced by chromatin but a mechanistic understanding is lacking. Using reconstituted nucleosomal DNA replication assays, we assessed the impact of nucleosomes on replication initiation. To generate distinct nucleosomal landscapes, different chromatin-remodeling enzymes (CREs) were used to remodel nucleosomes on origin-DNA templates. Nucleosomal organization influenced two steps of replication initiation: origin licensing and helicase activation. Origin licensing assays showed that local nucleosome positioning enhanced origin specificity and modulated helicase loading by influencing ORC DNA binding. Interestingly, SWI/SNF- and RSC-remodeled nucleosomes were permissive for origin licensing but showed reduced helicase activation. Specific CREs rescued replication of these templates if added prior to helicase activation, indicating a permissive chromatin state must be established during origin licensing to allow efficient origin activation. Our studies show nucleosomes directly modulate origin licensing and activation through distinct mechanisms and provide insights into the regulation of replication initiation by chromatin. DOI: http://dx.doi.org/10.7554/eLife.22512.001 PMID:28322723
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Pneumatic fractures in Confined Granular Media
NASA Astrophysics Data System (ADS)
Eriksen, Fredrik K.; Toussaint, Renaud; Jørgen Måløy, Knut; Grude Flekkøy, Eirik; Turkaya, Semih
2016-04-01
We will present our ongoing study of the patterns formed when air flows into a dry, non-cohesive porous medium confined in a horizontal Hele-Shaw cell. This is an optically transparent system consisting of two glass plates separated by 0.5 to 1 mm, containing a packing of dry 80 micron beads in between. The cell is rectangular and has an air-permeable boundary (blocking beads) at one short edge, while the other three edges are completely sealed. The granular medium is loosely packed against the semi-permeable boundary and fills about 80 % of the cell volume. This leaves an empty region at the sealed side, where an inlet allows us to set and maintain the air at a constant overpressure (0.1 - 2 bar). For the air trapped inside the cell to relax its overpressure it has to move through the deformable granular medium. Depending on the applied overpressure and initial density of the medium, we observe a range of different behaviors such as seepage through the pore-network with or without an initial compaction of the solid, formation of low density bubbles with rearrangement of particles, granular fingering/fracturing, and erosion inside formed channels/fractures. The experiments are recorded with a high-speed camera at a framerate of 1000 images/s and a resolution of 1024x1024 pixels. We use various image processing techniques to characterize the evolution of the air invasion patterns and the deformations in the surrounding material. The experiments are similar to deformation processes in porous media which are driven by pore fluid overpressure, such as mud volcanoes and hydraulic or pneumatic (gas-induced) fracturing, and the motivation is to increase the understanding of such processes by optical observations. In addition, this setup is an experimental version of the numerical models analyzed by Niebling et al. [1,2], and is useful for comparison with their results. In a directly related project [3], acoustic emissions from the cell plate are recorded during experiments, where we aim to localize acoustic events and correlate them with the optical observations. [1] Niebling M.J., Toussaint R., Flekkøy E.G. and Måløy K.J. (2012) Dynamic aerofracture of dense granular packings. Phys. Rev. E86, 061315. doi:10.1103/PhysRevE.86.061315 [2] Niebling M.J., Toussaint R., Flekkøy E.G. and Måløy K.J. (2012) Numerical studies of aerofractures in porous media. Rev. Cub. Fis. 29, 1E66 [3] Turkaya S., Toussaint R., Eriksen F.K., Zecevic M., Daniel G., Flekkøy E.G. and Måløy K.J. (2015)Bridging aero-fracture evolution with the characteristics of the acoustic emissions in a porous medium. Front. Phys. 3:70. doi: 10.3389/fphy.2015.00070
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Organizing Multiple Femtosecond Filaments in Air
NASA Astrophysics Data System (ADS)
Méchain, G.; Couairon, A.; Franco, M.; Prade, B.; Mysyrowicz, A.
2004-07-01
We show that it is possible to organize regular filamentation patterns in air by imposing either strong field gradients or phase distortions in the input-beam profile of an intense femtosecond laser pulse. A comparison between experiments and 3+1 dimensional numerical simulations confirms this concept and shows for the first time that a control of the transport of high intensities over long distances may be achieved by forcing this well ordered propagation regime. In this case, deterministic effects prevail in multiple femtosecond filamentation, and no transition to the optical turbulence regime is obtained [
Mlejnek et al., Phys. Rev. Lett. ].PRLTAO 0031-9007 83, 2938 (1999)10.1103/PhysRevLett.83.2938 -
3D modeling of lightning-induced electromagnetic pulses on Venus, Jupiter and Saturn
NASA Astrophysics Data System (ADS)
Pérez-Invernón, Francisco J.; Luque, Alejandro; Gordillo-Vázquez, Francisco J.
2017-04-01
Atmospheric electricity is a common phenomenon in some planets of The Solar System. We know that atmospheric discharges exist on Earth and gaseous planets; however, some characteristics of lightning on Saturn and Jupiter as well as their relevance on the effects of lightning in the atmospheres of these planets are still unknown. In the case of Venus, there exist some radio evidences of lightning, but the lack of optical observations suggests exploring indirect methods of detection, such as searching for lightning-induced transient optical emissions from the upper atmosphere. The Akatsuki probe, currently orbiting Venus, is equipped with a camera whose temporal resolution is high enough to detect optical emissions from lightning discharges and to measure nightglow enhancements. In this work, we extend previous models [1,2] to investigate the chemical impact and transient optical emissions produced by possible lightning-emitted electromagnetic pulses (EMP) in Venus, Saturn and Jupiter. Using a 3D FDTD ("Finite Differences Time Domain") model we solve the Maxwell equations coupled with the Langevin equation for electrons [3] and with a kinetic scheme, different for each planetary atmosphere. This method is useful to investigate the temporal and spatial impact of lightning-induced electromagnetic fields in the atmosphere of each planet for different lightning characteristics (e.g. energy released, orientation). This 3D FDTD model allows us to include the saturnian and jovian background magnetic field inclination and magnitude at different latitudes, and to determine the effects of different lightning channel inclinations. Results provide useful information to interpret lightning observations on giant gaseous planets and in the search for indirect optical signals from atmospheric discharge on Venus such as fast nightglow transient enhancements related to lightning as seen on Earth. Furthermore, we underline the observation of electrical discharges characteristics as a powerful tool to obtain information about planetary atmospheres, such as density profiles of electrons or other components. Our model may also be useful to extend some studies about the chemical impact of EMP pulses in the terrestrial atmosphere [4]. References [1] Luque, A., D. Dubrovin, F. J. Gordillo-Vázquez, U. Ebert, F. C. Parra-Rojas, Y. Yair, and C. Price (2014), Coupling between atmospheric layers in gaseous giant planets due to lightning-generated electromagnetic pulses, J. Geophys. Res. (Space Phys), 119, 8705, doi: 10.1002/2014JA020457. [2] Pérez-Invernón, F. J., A. Luque, and F. J. Gordillo-Vázquez (2016), Mesospheric optical signatures of possible lightning on Venus, J. Geophys. Res. (Space Phys), 121, 7026, doi: 10.1029/2016JA022886. [3] Lee, J. H., and D. K. Kalluri (1999), Three-dimensional FDTD simulation of electromagnetic wave transformation in a dynamic inhomogeneous magnetized plasma, IEEE Transactions on Antennas and Propagation, 47, 1146, doi:10.1109/8.785745. [4] Marshall, R. A., U. S. Inan, and V. S. Glukhov (2010), Elves and associated electron density changes due to cloud-to-ground and in-cloud lightning discharges, J. Geophys. Res. (Space Phys), 115, A00E17, doi:10.1029/2009JA014469.
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Initial Orbit Determination Based on Propagation of Admissible Regions with Differential Algebra
2017-01-19
Asteroid close encounter characterization using differential algebra: the case of aphophis. Celestial Mechanics and Dynamical Astronomy , 107(4), 2010...Mechanics and Dynamical Astronomy , 112 (3):331–352, 2012. ISSN 09232958. doi: 10.1007/s10569-012-9400-8. Roberto Armellin, Pierluigi Di Lizia, and Renato... Astronomy , 90(1-2):59–87, 2004. ISSN 09232958. doi: 10.1007/s10569-004-6593-5. 50 DISTRIBUTION A. Approved for public release: distribution unlimited
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Gagnon, Louis; Perdue, Katherine; Greve, Douglas N.; Goldenholz, Daniel; Kaskhedikar, Gayatri; Boas, David A.
2011-01-01
Diffuse Optical Imaging (DOI) allows the recovery of the hemodynamic response associated with evoked brain activity. The signal is contaminated with systemic physiological interference which occurs in the superficial layers of the head as well as in the brain tissue. The back-reflection geometry of the measurement makes the DOI signal strongly contaminated by systemic interference occurring in the superficial layers. A recent development has been the use of signals from small source-detector separation (1 cm) optodes as regressors. Since those additional measurements are mainly sensitive to superficial layers in adult humans, they help in removing the systemic interference present in longer separation measurements (3 cm). Encouraged by those findings, we developed a dynamic estimation procedure to remove global interference using small optode separations and to estimate simultaneously the hemodynamic response. The algorithm was tested by recovering a simulated synthetic hemodynamic response added over baseline DOI data acquired from 6 human subjects at rest. The performance of the algorithm was quantified by the Pearson R2 coefficient and the mean square error (MSE) between the recovered and the simulated hemodynamic responses. Our dynamic estimator was also compared with a static estimator and the traditional adaptive filtering method. We observed a significant improvement (two-tailed paired t-test, p < 0.05) in both HbO and HbR recovery using our Kalman filter dynamic estimator compared to the traditional adaptive filter, the static estimator and the standard GLM technique. PMID:21385616
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Proposed Budget for U.S. Geological Survey: A Mixed Bag of Increases and Cuts
NASA Astrophysics Data System (ADS)
Showstack, Randy
2011-03-01
Under the Obama administration's proposed fiscal year (FY) 2012 budget, the U.S. Geological Survey (USGS) would receive $1.1 billion, a scant $6.1 million more than the 2010 enacted budget. Within the agency, which is part of the Department of the Interior (DOI), some key initiatives slated for new or increased funding include the National Land Imaging Program, the USGS portion of the America's Great Outdoors Initiative, and DOI Climate Science Centers. However, the request also includes $89.1 million in program reductions and the elimination of some programs. With Congress currently considering a budget continuing resolution to fund the federal government through the end of the current fiscal year, 2011, USGS faces possible additional cuts.
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Hartmann, Bianca; Wai, Timothy; Hu, Hao; MacVicar, Thomas; Musante, Luciana; Fischer-Zirnsak, Björn; Stenzel, Werner; Gräf, Ralph; van den Heuvel, Lambert; Ropers, Hans-Hilger; Wienker, Thomas F; Hübner, Christoph; Langer, Thomas; Kaindl, Angela M
2016-01-01
Mitochondriopathies often present clinically as multisystemic disorders of primarily high-energy consuming organs. Assembly, turnover, and surveillance of mitochondrial proteins are essential for mitochondrial function and a key task of AAA family members of metalloproteases. We identified a homozygous mutation in the nuclear encoded mitochondrial escape 1-like 1 gene YME1L1, member of the AAA protease family, as a cause of a novel mitochondriopathy in a consanguineous pedigree of Saudi Arabian descent. The homozygous missense mutation, located in a highly conserved region in the mitochondrial pre-sequence, inhibits cleavage of YME1L1 by the mitochondrial processing peptidase, which culminates in the rapid degradation of YME1L1 precursor protein. Impaired YME1L1 function causes a proliferation defect and mitochondrial network fragmentation due to abnormal processing of OPA1. Our results identify mutations in YME1L1 as a cause of a mitochondriopathy with optic nerve atrophy highlighting the importance of YME1L1 for mitochondrial functionality in humans. DOI: http://dx.doi.org/10.7554/eLife.16078.001 PMID:27495975
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NASA Astrophysics Data System (ADS)
Chen, Chen; Klämpfl, Florian; Stelzle, Florian; Schmidt, Michael
2014-11-01
An imging resolution of micron-scale has not yet been discovered by diffuse optical imaging (DOI), while a superficial response was eliminated. In this work, we report on a new approach of DOI with a local off-set alignment to subvert the common boundary conditions of the modified Beer-Lambert Law (MBLL). It can resolve a superficial target in micron scale under a turbid media. To validate both major breakthroughs, this system was used to recover a subsurface microvascular mimicking structure under an skin equivalent phantom. This microvascular was included with oxy-hemoglobin solution in variant concentrations to distiguish the absolute values of CtRHb and CtHbO2 . Experimental results confirmed the feasibility of recovering the target vascular of 50 µm in diameter, and graded the values of the concentrations of oxy-hemoglobin from 10 g/L to 50 g/L absolutely. Ultimately, this approach could evolve into a non-invasive imaging system to map the microvascular pattern and the associated oximetry under a human skin in-vivo.
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NASA Astrophysics Data System (ADS)
Kuang, Zhonghua; Yang, Qian; Wang, Xiaohui; Fu, Xin; Ren, Ning; Sang, Ziru; Wu, San; Zheng, Yunfei; Zhang, Xianming; Hu, Zhanli; Du, Junwei; Liang, Dong; Liu, Xin; Zheng, Hairong; Yang, Yongfeng
2018-02-01
Detectors with depth-encoding capability and good timing resolution are required to develop high-performance whole-body or total-body PET scanners. In this work, depth-encoding PET detectors that use light sharing between two discrete crystals and single-ended readout with silicon photomultipliers (SiPMs) were manufactured and evaluated. The detectors consisted of two unpolished 3 × 3 × 20 mm3 LYSO crystals with different coupling materials between them and were read out by Hamamatsu 3 × 3 mm2 SiPMs with one-to-one coupling. The ratio of the energy of one SiPM to the total energy of two SiPMs was used to measure the depth of interaction (DOI). Detectors with different coupling materials in-between the crystals were measured in the singles mode in an effort to obtain detectors that can provide good DOI resolution. The DOI resolution and energy resolution of three types of detector were measured and the timing resolution was measured for the detector with the best DOI and energy resolution. The optimum detector, with 5 mm optical glue, a 9 mm triangular ESR and a 6 mm rectangular ESR in-between the unpolished crystals, provides a DOI resolution of 2.65 mm, an energy resolution of 10.0% and a timing resolution of 427 ps for events of E > 400 keV. The detectors simultaneously provide good DOI and timing resolution, and show great promise for the development of high-performance whole-body and total-body PET scanners.
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NASA Astrophysics Data System (ADS)
Vignelles, Damien; Berthet, Bwenael; Renard, Jean-Baptiste; Rieger, Landon; Bourassa, Adam; Vernier, Jean-Paul; Taha, Ghassan; Khaykin, Sergey; Lurton, Thibaut; Jegou, Fabrice; Couté, Benoît; Duverger, Vincent
2017-04-01
Stratospheric aerosols contribute to the terrestrial radiative budget during large eruptive events but also during volcanic quiescent periods (Kremser et al. 2016). The survey of background stratospheric aerosols, especially in the middle stratosphere, is challenging due to extreme experimental conditions and low particle concentration. Furthermore, during periods of low volcanic activity, origins and optical properties of aerosols in the middle and high stratosphere are not well defined yet (Neely et al. 2011). We propose to study the capabilities of a new miniature particle counter called LOAC (Light Optical Aerosol Counter), light enough to be carried under meteorological balloons, whichensure a very good frequency of flights and designed to be able to measure and discriminate between several main aerosol types. The LOAC miniature particle counter has been initially designed for balloon-borne tropospheric studies (Renard et al. 2016).Metrological performances of the LOAC instrument have been determined in the laboratory and during balloon flights. Principal limitations of the use of LOAC in the stratosphere areinduced by the temperature variations and the influence of cosmic rays. A detection threshold has been determined in the laboratory to be of 0.8 particule.cm-3 in terms of concentration which also limits the use of LOAC in the stratosphere where aerosol concentrations during volcanic quiescent periods may be lower than this limit. Since June 2013, more than 100 hundred LOAC instruments have been launched under meteorological balloons during the ChArMEx and Voltaire-LOAC field campaigns. This dataset has been studied and compared to satellite records such as OSIRIS, OMPS, and CALIOPbut also to ground-based lidar data (NDACC lidar OHP) and outputs from the WACCM/CARMA model. Results show that large variations in stratospheric aerosols are well defined by satellite but less visible in LOAC records. Instrumental LOAC limitations in the stratosphere can explain some of the difference between remote sensing methods and in-situ measurements but suggest also that local variations in the stratospheric aerosol contents may exist during volcanic quiescent periods. Flights made through the Calbucoplume in stratosphere during the summer 2015 show that LOAC can describe distribution in size and particle concentrations in a perturbed lower stratosphere. In the stratosphere free of volcanic influence, an integration time of 10 minutes shows better results. Kremser et al. (2016) Stratospheric aerosol—Observations, processes, and impact on climate. Rev. Geophys. 54, 2015RG000511. doi:10.1002/2015RG000511 Neely, R.R., English, J.M., Toon, O.B., Solomon, S., Mills, M., Thayer, J.P., 2011. Implications of extinction due to meteoritic smoke in the upper stratosphere: EXTINCTION DUE TO METEORITIC SMOKE. Geophys. Res. Lett. 38, doi:10.1029/2011GL049865 Renard et al. (2016) LOAC: a small aerosol optical sounter/sizer for ground-based and balloon measurements AMT. 9, 1721-1742. doi:10.5194/amt-9-1724-2016
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An All-Sky Portable (ASP) Optical Catalogue
NASA Astrophysics Data System (ADS)
Flesch, Eric Wim
2017-06-01
This optical catalogue combines the all-sky USNO-B1.0/A1.0 and most-sky APM catalogues, plus overlays of SDSS optical data, into a single all-sky map presented in a sparse binary format that is easily downloaded at 9 Gb zipped. Total count is 1 163 237 190 sources and each has J2000 astrometry, red and blue magnitudes with PSFs and variability indicator, and flags for proper motion, epoch, and source survey and catalogue for each of the photometry and astrometry. The catalogue is available on http://quasars.org/asp.html, and additional data for this paper is available at http://dx.doi.org/10.4225/50/5807fbc12595f.
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WE-C-217BCD-10: Development of High Performance PET for Animal Imaging and Therapy Applications.
Shao, Y; Sun, X; Lan, K; Bircher, C
2012-06-01
A prototype small animal PET is developed with several novel technologies to measure 3D gamma-interaction positions and to substantially improve imaging performance. Each new detector has an 8×8 array of 1.95×1.95×30 mm̂3 LYSO scintillators, with each end optically connected to a solid-state photo multiplier (SSPM) array through a light guide. This dual-ended-readout enables the depth-of-interaction (DOI) measurement. Each SSPM array has 16 SSPMs arranged in a 4×4 matrix. Each SSPM has active area about 3×3 mm̂2, with its output read by an ASIC electronics that directly converts analog signals to digital timing pulses which encode the interaction information for energy, timing, crystal of interaction, and DOI calculations. These digital pulses are transferred to and decoded by FPGA-based TDC for coincident event selection and data acquisition. This independent readout of each SSPM and parallel signal process significantly improve signal-to-noise ratio and permit applying flexible data processing algorithms. The current prototype system consists of two rotating detector panels on a portable gantry, with 4 detectors linearly packed together in each panel to provide ∼16 mm axial and variable trans- axial FOV with adjustable panel-to-panel distance. List-mode OSEM-based image reconstruction with resolution modeling was implemented. Both Na- 22 point source and phantom were used to evaluate the system performance. The measured energy, timing, spatial and DOI resolutions for each crystal were around 16%, 2.6 ns, 2.0 mm and 5.0 mm, respectively. The measured spatial resolutions with DOI were ∼1.7 mm across the entire FOV in all direction, while those without DOI were much worse and non-uniform across the FOV, in the range predominately around 3.0 to 4.0 mm. In addition, images from a F-18 hot-rod phantom with DOI show significantly improved quality compared to those without DOI. DOI- measurable PET shows substantially improved image performance for a compact system. National Institute of Health. University of Texas MD Anderson Cancer Center. © 2012 American Association of Physicists in Medicine.
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NASA Astrophysics Data System (ADS)
Baili, Amira; Cherif, Rim; Zghal, Mourad
2016-09-01
This paper, originally published on September 15, 2016, was retracted from the SPIE Digital Library on October 5, 2016, due to a high degree of similarity between specific portions of the text of the paper to the following publications: J. Tchahame, J. Beugnot, A. Kudlinski, and T. Sylvestre, "Multimode Brillouin spectrum in a long tapered birefringent photonic crystal fiber," Opt. Lett. 40, 4281-4284 (2015). doi: 10.1364/OL.40.004281 W. W. Ke, X. J. Wang and X. Tang, "Stimulated Brillouin Scattering Model in Multi-Mode Fiber Lasers," in IEEE Journal of Selected Topics in Quantum Electronics, vol. 20, no. 5, pp. 305-314, Sept.-Oct. 2014. doi: 10.1109/JSTQE.2014.2303256.
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2012-01-01
34Laser oscillations in nd-doped yttrium aluminum , yttrium gallium and gadolinium garnets ," Applied Physics Letters (10): 182. doi:10.1063/1.1753928...Aluminium Garnet ) Nd:YAG lasers, and inherent of this material is its fundamental 1064nm frequency that is frequency doubled to 532 nm to penetrate
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The effect of different anesthetics on neurovascular coupling
Franceschini, Maria Angela; Radhakrishnan, Harsha; Thakur, Kiran; Wu, Weicheng; Ruvinskaya, Svetlana; Carp, Stefan; Boas, David A.
2010-01-01
To date, the majority of neurovascular coupling studies focused on the thalamic afferents' activity in layer IV and the corresponding large spiking activity as responsible for functional hyperemia. This paper highlights the role of the secondary and late cortico-cortical transmission in neurovascular coupling. Simultaneous scalp electroencephalography (EEG) and diffuse optical imaging (DOI) measurements were obtained during multiple conditions of event-related electrical forepaw stimulation in 33 male Sprague-Dawley rats divided into 6 groups depending on the maintaining anesthetic - alpha-chloralose, pentobarbital, ketamine-xylazine, fentanyl-droperidol, isoflurane, or propofol. The somatosensory evoked potentials (SEP) were decomposed into four components and the question of which best predicts the hemodynamic responses was investigated. Results of the linear regression analysis show that the hemodynamic response is best correlated with the secondary and late cortico-cortical transmissions and not with the initial thalamic input activity in layer IV. Baseline cerebral blood flow (CBF) interacts with neural activity and influences the evoked hemodynamic responses. Finally, neurovascular coupling appears to be the same across all anesthetics used. PMID:20350606
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Federal Register 2010, 2011, 2012, 2013, 2014
2011-02-09
... Interior's (DOI) ``Smart from the Start'' wind energy initiative, to identify areas for wind energy leasing... November 23, 2010, Secretary of the Interior Ken Salazar announced the ``Smart from the Start'' renewable... the ``Smart from the Start'' initiative can be found at http://www.boemre.gov/offshore/RenewableEnergy...
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Calcium handling precedes cardiac differentiation to initiate the first heartbeat
Tyser, Richard CV; Miranda, Antonio MA; Chen, Chiann-mun; Davidson, Sean M
2016-01-01
The mammalian heartbeat is thought to begin just prior to the linear heart tube stage of development. How the initial contractions are established and the downstream consequences of the earliest contractile function on cardiac differentiation and morphogenesis have not been described. Using high-resolution live imaging of mouse embryos, we observed randomly distributed spontaneous asynchronous Ca2+-oscillations (SACOs) in the forming cardiac crescent (stage E7.75) prior to overt beating. Nascent contraction initiated at around E8.0 and was associated with sarcomeric assembly and rapid Ca2+ transients, underpinned by sequential expression of the Na+-Ca2+ exchanger (NCX1) and L-type Ca2+ channel (LTCC). Pharmacological inhibition of NCX1 and LTCC revealed rapid development of Ca2+ handling in the early heart and an essential early role for NCX1 in establishing SACOs through to the initiation of beating. NCX1 blockade impacted on CaMKII signalling to down-regulate cardiac gene expression, leading to impaired differentiation and failed crescent maturation. DOI: http://dx.doi.org/10.7554/eLife.17113.001 PMID:27725084
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Medhi, Darpan; Goldman, Alastair SH; Lichten, Michael
2016-01-01
The budding yeast genome contains regions where meiotic recombination initiates more frequently than in others. This pattern parallels enrichment for the meiotic chromosome axis proteins Hop1 and Red1. These proteins are important for Spo11-catalyzed double strand break formation; their contribution to crossover recombination remains undefined. Using the sequence-specific VMA1-derived endonuclease (VDE) to initiate recombination in meiosis, we show that chromosome structure influences the choice of proteins that resolve recombination intermediates to form crossovers. At a Hop1-enriched locus, most VDE-initiated crossovers, like most Spo11-initiated crossovers, required the meiosis-specific MutLγ resolvase. In contrast, at a locus with lower Hop1 occupancy, most VDE-initiated crossovers were MutLγ-independent. In pch2 mutants, the two loci displayed similar Hop1 occupancy levels, and VDE-induced crossovers were similarly MutLγ-dependent. We suggest that meiotic and mitotic recombination pathways coexist within meiotic cells, and that features of meiotic chromosome structure determine whether one or the other predominates in different regions. DOI: http://dx.doi.org/10.7554/eLife.19669.001 PMID:27855779
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Colman, John A.
2007-01-01
IntroductionAs part of the Department of the Interior (DOI) program Science on the DOI Landscape Initiative, the U.S. Geological Survey (USGS), Eastern Region, held a workshop during August 17–18, 2004, in Reston, VA, on mercury in the environment as it relates to DOI resource management. DOI bureaus manage millions of acres of land and offshore resources subject to mercury deposition and to the effects of mercury on ecosystems and human health. The goals of the workshop were to (1) summarize information on mercury sources and cycling on DOI lands in the eastern United States, (2) learn the perspectives of the DOI bureaus regarding mercury on DOI lands, (3) provide information to DOI land managers about monitoring mercury and minimizing mercury accumulation in wildlife and humans, and (4) consider future directions for mercury monitoring and research on DOI lands. The workshop focused on mercury research as it relates to DOI resource-management issues primarily in the eastern part of the United States (east of the Mississippi River). Topics included the influence of ecosystem setting on mercury biogeochemical transformation, land- and air-management practices as they affect mercury in the environment, mercury source issues, and effects of mercury on humans and wildlife. Mercury research topics were addressed by 24 invited oral presentations and 30 contributed posters. The perspectives of the DOI bureaus and land managers were addressed through a panel of scientists from the DOI resource-management bureaus and a Chippewa Indian Tribe of Minnesota. Discussion at the conclusion of the workshop was directed toward goals and long-term strategies for mercury research that will benefit DOI resource management. The panel, presentations, and discussions were videotaped and are available at the following URL, along with the slides presented: http://www.usgs.gov/mercury/2004workshop/ Abstracts from the presentations and posters are included in this report, together with summaries of each presentation session. The abstracts in this volume that were written by U.S. Geological Survey authors were reviewed and approved for publication by the Survey. Abstracts submitted by researchers from academia and from state and other federal agencies are published as part of these proceedings, but do not necessarily reflect the Survey’s policies and views. The use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
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NASA Astrophysics Data System (ADS)
Chen, Yiping; Xianyu, Yunlei; Sun, Jiashu; Niu, Yajing; Wang, Yu; Jiang, Xingyu
2015-12-01
This report shows that immunomagnetic beads (IMBs) can act as the optical readout for assays, in addition to serving as the carrier for purification/separation. Under the influence of an external magnet, IMBs are attracted to coat one side of a test tube. IMBs specifically bound to targets can form a narrow brown stripe, whereas free IMBs will form a diffuse, yellow coating on the side of the test tube. Target analytes can aggregate initially dispersed IMBs in a sample concentration-dependent manner, yielding a color change from yellow to brown that can be seen with the naked eye. This assay combines the convenience of a lateral flow assay, allowing a one-step assay to finish within 15 min, with the sensitivity of an enzyme-linked immonosorbent assay.This report shows that immunomagnetic beads (IMBs) can act as the optical readout for assays, in addition to serving as the carrier for purification/separation. Under the influence of an external magnet, IMBs are attracted to coat one side of a test tube. IMBs specifically bound to targets can form a narrow brown stripe, whereas free IMBs will form a diffuse, yellow coating on the side of the test tube. Target analytes can aggregate initially dispersed IMBs in a sample concentration-dependent manner, yielding a color change from yellow to brown that can be seen with the naked eye. This assay combines the convenience of a lateral flow assay, allowing a one-step assay to finish within 15 min, with the sensitivity of an enzyme-linked immonosorbent assay. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr07044a
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Cassini ISS Observations of Jupiter: An Exoplanet Perspective
NASA Astrophysics Data System (ADS)
West, Robert A.; Knowles, Benjamin
2017-10-01
Understanding the optical and physical properties of planets in our solar system can guide our approach to the interpretation of observations of exoplanets. Although some work has already been done along these lines, there remain low-hanging fruit. During the Cassini Jupiter encounter, the Imaging Science Subsystem (ISS) obtained an extensive set of images over a large range of phase angles (near-zero to 140 degrees) and in filters from near-UV to near-IR, including three methane bands and nearby continuum. The ISS also obtained images using polarizers. Much later in the mission we also obtained distant images while in orbit around Saturn. Some of these data have already been studied to reveal phase behavior (Dyudina et al., Astrophys. J.822, DOI: 10.3847/0004-637X/822/2/76; Mayorga et al., 2016, Astron. J. 152, DOI: 10.3847/0004-6256/152/6/209). Here we examine rotational modulation to determine wavelength and phase angle dependence, and how these may depend on cloud and haze vertical structure and optical properties. The existence of an optically thin forward-scattering and longitudinally-homogeneous haze overlying photometrically-variable cloud fields tends to suppress rotational modulation as phase angle increases, although in the strong 890-nm methane band cloud vertical structure is important. Cloud particles (non-spherical ammonia ice, mostly) have very small polarization signatures at intermediate phase angles and rotational modulation is not apparent above the noise level of our instrument. Part of this work was performed by the Jet Propulsion Lab, Cal. Inst. Of Technology.
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Schindler, Emmanuelle A D; Harvey, John A; Aloyo, Vincent J
2013-01-23
The phenethylamine and indoleamine classes of hallucinogens demonstrate distinct pharmacological properties, although they share a serotonin(2A) (5-HT(2A)) receptor mechanism of action (MOA). The 5-HT(2A) receptor signals through phosphatidylinositol (PI) hydrolysis, which is initiated upon activation of phospholipase C (PLC). The role of PI hydrolysis in the effects of hallucinogens remains unclear. In order to better understand the role of PI hydrolysis in the MOA of hallucinogens, the PLC inhibitor, 1-[6-((17β-3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl]-1H-pyrrole-2,5-dione (U73122), was used to study the effects of two hallucinogens, the phenethylamine, (±)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI), and the indoleamine, lysergic acid diethylamide (LSD). PI hydrolysis was quantified through release of [3H]inositol-4-phosphate from living rabbit frontocortical tissue prisms. Head bobs were counted after hallucinogens were infused into the medial prefrontal cortex (mPFC) of rabbits. Both DOI and LSD stimulated PI hydrolysis in frontocortical tissue through activation of PLC. DOI-stimulated PI hydrolysis was blocked by 5-HT(2A/2C) receptor antagonist, ketanserin, whereas the LSD signal was blocked by 5-HT(2B/2C) receptor antagonist, SB206553. When infused into the mPFC, both DOI- and LSD-elicited head bobs. Pretreatment with U73122 blocked DOI-, but not LSD-elicited head bobs. The two hallucinogens investigated were distinct in their activation of the PI hydrolysis signaling pathway. The serotonergic receptors involved with DOI and LSD signals in frontocortical tissue were different. Furthermore, PLC activation in mPFC was necessary for DOI-elicited head bobs, whereas LSD-elicited head bobs were independent of this pathway. These novel findings urge closer investigation into the intracellular mechanism of action of these unique compounds. Published by Elsevier B.V.
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Madsen, Heidi Holst; Madsen, Dicte; Gauffriau, Marianne
2016-01-01
Unique identifiers (UID) are seen as an effective key to match identical publications across databases or identify duplicates in a database. The objective of the present study is to investigate how well UIDs work as match keys in the integration between Pure and SciVal, based on a case with publications from the health sciences. We evaluate the matching process based on information about coverage, precision, and characteristics of publications matched versus not matched with UIDs as the match keys. We analyze this information to detect errors, if any, in the matching process. As an example we also briefly discuss how publication sets formed by using UIDs as the match keys may affect the bibliometric indicators number of publications, number of citations, and the average number of citations per publication. The objective is addressed in a literature review and a case study. The literature review shows that only a few studies evaluate how well UIDs work as a match key. From the literature we identify four error types: Duplicate digital object identifiers (DOI), incorrect DOIs in reference lists and databases, DOIs not registered by the database where a bibliometric analysis is performed, and erroneous optical or special character recognition. The case study explores the use of UIDs in the integration between the databases Pure and SciVal. Specifically journal publications in English are matched between the two databases. We find all error types except erroneous optical or special character recognition in our publication sets. In particular the duplicate DOIs constitute a problem for the calculation of bibliometric indicators as both keeping the duplicates to improve the reliability of citation counts and deleting them to improve the reliability of publication counts will distort the calculation of average number of citations per publication. The use of UIDs as a match key in citation linking is implemented in many settings, and the availability of UIDs may become critical for the inclusion of a publication or a database in a bibliometric analysis.
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Madsen, Heidi Holst; Madsen, Dicte; Gauffriau, Marianne
2016-01-01
Unique identifiers (UID) are seen as an effective key to match identical publications across databases or identify duplicates in a database. The objective of the present study is to investigate how well UIDs work as match keys in the integration between Pure and SciVal, based on a case with publications from the health sciences. We evaluate the matching process based on information about coverage, precision, and characteristics of publications matched versus not matched with UIDs as the match keys. We analyze this information to detect errors, if any, in the matching process. As an example we also briefly discuss how publication sets formed by using UIDs as the match keys may affect the bibliometric indicators number of publications, number of citations, and the average number of citations per publication. The objective is addressed in a literature review and a case study. The literature review shows that only a few studies evaluate how well UIDs work as a match key. From the literature we identify four error types: Duplicate digital object identifiers (DOI), incorrect DOIs in reference lists and databases, DOIs not registered by the database where a bibliometric analysis is performed, and erroneous optical or special character recognition. The case study explores the use of UIDs in the integration between the databases Pure and SciVal. Specifically journal publications in English are matched between the two databases. We find all error types except erroneous optical or special character recognition in our publication sets. In particular the duplicate DOIs constitute a problem for the calculation of bibliometric indicators as both keeping the duplicates to improve the reliability of citation counts and deleting them to improve the reliability of publication counts will distort the calculation of average number of citations per publication. The use of UIDs as a match key in citation linking is implemented in many settings, and the availability of UIDs may become critical for the inclusion of a publication or a database in a bibliometric analysis. PMID:27635223
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An edge-readout, multilayer detector for positron emission tomography.
Li, Xin; Ruiz-Gonzalez, Maria; Furenlid, Lars R
2018-06-01
We present a novel gamma-ray-detector design based on total internal reflection (TIR) of scintillation photons within a crystal that addresses many limitations of traditional PET detectors. Our approach has appealing features, including submillimeter lateral resolution, DOI positioning from layer thickness, and excellent energy resolution. The design places light sensors on the edges of a stack of scintillator slabs separated by small air gaps and exploits the phenomenon that more than 80% of scintillation light emitted during a gamma-ray event reaches the edges of a thin crystal with polished faces due to TIR. Gamma-ray stopping power is achieved by stacking multiple layers, and DOI is determined by which layer the gamma ray interacts in. The concept of edge readouts of a thin slab was verified by Monte Carlo simulation of scintillation light transport. An LYSO crystal of dimensions 50.8 mm × 50.8 mm × 3.0 mm was modeled with five rectangular SiPMs placed along each edge face. The mean-detector-response functions (MDRFs) were calculated by simulating signals from 511 keV gamma-ray interactions in a grid of locations. Simulations were carried out to study the influence of choice of scintillator material and dimensions, gamma-ray photon energies, introduction of laser or mechanically induced optical barriers (LIOBs, MIOBs), and refractive indices of optical-coupling media and SiPM windows. We also analyzed timing performance including influence of gamma-ray interaction position and presence of optical barriers. We also modeled and built a prototype detector, a 27.4 mm × 27.4 mm × 3.0 mm CsI(Tl) crystal with 4 SiPMs per edge to experimentally validate the results predicted by the simulations. The prototype detector used CsI(Tl) crystals from Proteus outfitted with 16 Hamamatsu model S13360-6050PE MPPCs read out by an AiT-16-channel readout. The MDRFs were measured by scanning the detector with a collimated beam of 662-keV photons from a 137 Cs source. The spatial resolution was experimentally determined by imaging a tungsten slit that created a beam of 0.44 mm (FWHM) width normal to the detector surface. The energy resolution was evaluated by analyzing list-mode data from flood illumination by the 137 Cs source. We find that in a block-detector-sized LYSO layer read out by five SiPMs per edge, illuminated by 511-keV photons, the average resolution is 1.49 mm (FWHM). With the introduction of optical barriers, average spatial resolution improves to 0.56 mm (FWHM). The DOI resolution is the layer thickness of 3.0 mm. We also find that optical-coupling media and SiPM-window materials have an impact on spatial resolution. The timing simulation with LYSO crystal yields a coincidence resolving time (CRT) of 200-400 ps, which is slightly position dependent. And the introduction of optical barriers has minimum influence. The prototype CsI(Tl) detector, with a smaller area and fewer SiPMs, was measured to have central-area spatial resolutions of 0.70 and 0.39 mm without and with optical barriers, respectively. These results match well with our simulations. An energy resolution of 6.4% was achieved at 662 keV. A detector design based on a stack of monolithic scintillator layers that uses edge readouts offers several advantages over current block detectors for PET. For example, there is no tradeoff between spatial resolution and detection sensitivity since no reflector material displaces scintillator crystal, and submillimeter resolution can be achieved. DOI information is readily available, and excellent timing and energy resolutions are possible. © 2018 The Authors. Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.
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Time-over-threshold for pulse shape discrimination in a time-of-flight phoswich PET detector.
Chang, Chen-Ming; Cates, Joshua W; Levin, Craig S
2017-01-07
It is well known that a PET detector capable of measuring both photon time-of-flight (TOF) and depth-of-interaction (DOI) improves the image quality and accuracy. Phoswich designs have been realized in PET detectors to measure DOI for more than a decade. However, PET detectors based on phoswich designs put great demand on the readout circuits, which have to differentiate the pulse shape produced by different crystal layers. A simple pulse shape discrimination approach is required to realize the phoswich designs in a clinical PET scanner, which consists of thousands of scintillation crystal elements. In this work, we studied time-over-threshold (ToT) as a pulse shape parameter for DOI. The energy, timing and DOI performance were evaluated for a phoswich detector design comprising [Formula: see text] mm LYSO:Ce crystal optically coupled to [Formula: see text] mm calcium co-doped LSO:Ce,Ca(0.4%) crystal read out by a silicon photomultiplier (SiPM). A DOI accuracy of 97.2% has been achieved for photopeak events using the proposed time-over-threshold (ToT) processing. The energy resolution without correction for SiPM non-linearity was [Formula: see text]% and [Formula: see text]% FWHM at 511 keV for LYSO and LSO crystal layers, respectively. The coincidence time resolution for photopeak events ranges from 164.6 ps to 183.1 ps FWHM, depending on the layer combinations. The coincidence time resolution for inter-crystal scatter events ranges from 214.6 ps to 418.3 ps FWHM, depending on the energy windows applied. These results show great promises of using ToT for pulse shape discrimination in a TOF phoswich detector since a ToT measurement can be easily implemented in readout electronics.
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Center for Hybrid Communications and Networks
2016-09-08
Transmission loop experimental setup to study coded modulation and turbo equalization for metro and long-haul networks, 3) Experimental setup for...undertaking fundamental studies of QKD systems that use ( hyper -) entangled photon pairs or weak coherent states (WCS) as the quantum resources...onlinelibrary.wiley.com/doi/10.1002/047134608X.W8291/abstract] The real-time scope and AWG are also used in fiber-optics transmission loop experiment we
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Department of Interior Focuses on Cleaning Products
A November 1998 effort to address concerns over the indoor air quality in their buildings in DC led the Department of the Interior (DOI) to initiate a contract for custodial services using environmentally preferable cleaning products and supplies.
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A continuum model of transcriptional bursting
Corrigan, Adam M; Tunnacliffe, Edward; Cannon, Danielle; Chubb, Jonathan R
2016-01-01
Transcription occurs in stochastic bursts. Early models based upon RNA hybridisation studies suggest bursting dynamics arise from alternating inactive and permissive states. Here we investigate bursting mechanism in live cells by quantitative imaging of actin gene transcription, combined with molecular genetics, stochastic simulation and probabilistic modelling. In contrast to early models, our data indicate a continuum of transcriptional states, with a slowly fluctuating initiation rate converting the gene between different levels of activity, interspersed with extended periods of inactivity. We place an upper limit of 40 s on the lifetime of fluctuations in elongation rate, with initiation rate variations persisting an order of magnitude longer. TATA mutations reduce the accessibility of high activity states, leaving the lifetime of on- and off-states unchanged. A continuum or spectrum of gene states potentially enables a wide dynamic range for cell responses to stimuli. DOI: http://dx.doi.org/10.7554/eLife.13051.001 PMID:26896676
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Tissue absence initiates regeneration through follistatin-mediated inhibition of activin signaling.
Gaviño, Michael A; Wenemoser, Danielle; Wang, Irving E; Reddien, Peter W
2013-09-10
Regeneration is widespread, but mechanisms that activate regeneration remain mysterious. Planarians are capable of whole-body regeneration and mount distinct molecular responses to wounds that result in tissue absence and those that do not. A major question is how these distinct responses are activated. We describe a follistatin homolog (Smed-follistatin) required for planarian regeneration. Smed-follistatin inhibition blocks responses to tissue absence but does not prevent normal tissue turnover. Two activin homologs (Smed-activin-1 and Smed-activin-2) are required for the Smed-follistatin phenotype. Finally, Smed-follistatin is wound-induced and expressed at higher levels following injuries that cause tissue absence. These data suggest that Smed-follistatin inhibits Smed-Activin proteins to trigger regeneration specifically following injuries involving tissue absence and identify a mechanism critical for regeneration initiation, a process important across the animal kingdom. DOI:http://dx.doi.org/10.7554/eLife.00247.001.
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A handheld wireless device for diffuse optical spectroscopic assessment of infantile hemangiomas
NASA Astrophysics Data System (ADS)
Fong, Christopher J.; Flexman, Molly; Hoi, Jennifer W.; Geller, Lauren; Garzon, Maria; Kim, Hyun K.; Hielscher, Andreas H.
2013-03-01
Infantile hemangiomas (IH) are common vascular growths that occur in 5-10% of neonates and have the potential to cause disfiguring and even life-threatening complications. With no objective tool to monitor IH, a handheld wireless device (HWD) that uses diffuse optical spectroscopy has been developed for use in assessment of IH by measurements in absolute oxygenated and deoxygenated hemoglobin concentration as well as scattering in tissue. Reconstructions of these variables can be computed using a multispectral evolution algorithm. We validated the new system by experimental studies using phantom experiments and a clinical study is under way to assess the utility of DOI for IH.
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Hernández-Pinilla, D; Rodríguez-Palomo, A; Álvarez-Fraga, L; Céspedes, E; Prieto, J E; Muñoz-Martín, A; Prieto, C
2016-06-01
Data of optical performance, thermal stability and ageing are given for solar selective coatings (SSC) based on a novel MoSi2-Si3N4 absorbing composite. SSC have been prepared as multilayer stacks formed by silver as metallic infrared reflector, a double layer composite and an antireflective layer (doi: 10.1016/j.solmat.2016.04.001 [1]). Spectroscopic reflectance data corresponding to the optical performance of samples after moderate vacuum annealing at temperatures up to 600 °C and after ageing test of more than 200 h with several heating-cooling cycles are shown here.
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Method for producing damage resistant optics
Hackel, Lloyd A.; Burnham, Alan K.; Penetrante, Bernardino M.; Brusasco, Raymond M.; Wegner, Paul J.; Hrubesh, Lawrence W.; Kozlowski, Mark R.; Feit, Michael D.
2003-01-01
The present invention provides a system that mitigates the growth of surface damage in an optic. Damage to the optic is minimally initiated. In an embodiment of the invention, damage sites in the optic are initiated, located, and then treated to stop the growth of the damage sites. The step of initiating damage sites in the optic includes a scan of the optic using a laser to initiate defects. The exact positions of the initiated sites are identified. A mitigation process is performed that locally or globally removes the cause of subsequent growth of the damaged sites.
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Taylor, Benjamin JM; Wu, Yee Ling; Rada, Cristina
2014-01-01
Cytidine deaminases are single stranded DNA mutators diversifying antibodies and restricting viral infection. Improper access to the genome leads to translocations and mutations in B cells and contributes to the mutation landscape in cancer, such as kataegis. It remains unclear how deaminases access double stranded genomes and whether off-target mutations favor certain loci, although transcription and opportunistic access during DNA repair are thought to play a role. In yeast, AID and the catalytic domain of APOBEC3G preferentially mutate transcriptionally active genes within narrow regions, 110 base pairs in width, fixed at RNA polymerase initiation sites. Unlike APOBEC3G, AID shows enhanced mutational preference for small RNA genes (tRNAs, snoRNAs and snRNAs) suggesting a putative role for RNA in its recruitment. We uncover the high affinity of the deaminases for the single stranded DNA exposed by initiating RNA polymerases (a DNA configuration reproduced at stalled polymerases) without a requirement for specific cofactors. DOI: http://dx.doi.org/10.7554/eLife.03553.001 PMID:25237741
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The acinar differentiation determinant PTF1A inhibits initiation of pancreatic ductal adenocarcinoma
Krah, Nathan M; De La O, Jean-Paul; Swift, Galvin H; Hoang, Chinh Q; Willet, Spencer G; Chen Pan, Fong; Cash, Gabriela M; Bronner, Mary P; Wright, Christopher VE; MacDonald, Raymond J; Murtaugh, L Charles
2015-01-01
Understanding the initiation and progression of pancreatic ductal adenocarcinoma (PDAC) may provide therapeutic strategies for this deadly disease. Recently, we and others made the surprising finding that PDAC and its preinvasive precursors, pancreatic intraepithelial neoplasia (PanIN), arise via reprogramming of mature acinar cells. We therefore hypothesized that the master regulator of acinar differentiation, PTF1A, could play a central role in suppressing PDAC initiation. In this study, we demonstrate that PTF1A expression is lost in both mouse and human PanINs, and that this downregulation is functionally imperative in mice for acinar reprogramming by oncogenic KRAS. Loss of Ptf1a alone is sufficient to induce acinar-to-ductal metaplasia, potentiate inflammation, and induce a KRAS-permissive, PDAC-like gene expression profile. As a result, Ptf1a-deficient acinar cells are dramatically sensitized to KRAS transformation, and reduced Ptf1a greatly accelerates development of invasive PDAC. Together, these data indicate that cell differentiation regulators constitute a new tumor suppressive mechanism in the pancreas. DOI: http://dx.doi.org/10.7554/eLife.07125.001 PMID:26151762
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Zhang, Zhengjian; Boskovic, Zarko; Hussain, Mahmud M; Hu, Wenxin; Inouye, Carla; Kim, Han-Je; Abole, A Katherine; Doud, Mary K; Lewis, Timothy A; Koehler, Angela N; Schreiber, Stuart L; Tjian, Robert
2015-01-01
Intrinsically disordered proteins/regions (IDPs/IDRs) are proteins or peptide segments that fail to form stable 3-dimensional structures in the absence of partner proteins. They are abundant in eukaryotic proteomes and are often associated with human diseases, but their biological functions have been elusive to study. In this study, we report the identification of a tin(IV) oxochloride-derived cluster that binds an evolutionarily conserved IDR within the metazoan TFIID transcription complex. Binding arrests an isomerization of promoter-bound TFIID that is required for the engagement of Pol II during the first (de novo) round of transcription initiation. However, the specific chemical probe does not affect reinitiation, which requires the re-entry of Pol II, thus, mechanistically distinguishing these two modes of transcription initiation. This work also suggests a new avenue for targeting the elusive IDRs by harnessing certain features of metal-based complexes for mechanistic studies, and for the development of novel pharmaceutical interventions. DOI: http://dx.doi.org/10.7554/eLife.07777.001 PMID:26314865
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Two months of disdrometer data in the Paris area
NASA Astrophysics Data System (ADS)
Gires, Auguste; Tchiguirinskaia, Ioulia; Schertzer, Daniel
2018-05-01
The Hydrology, Meteorology, and Complexity laboratory of École des Ponts ParisTech (hmco.enpc.fr) has made a data set of optical disdrometer measurements available that come from a campaign involving three collocated devices from two different manufacturers, relying on different underlying technologies (one Campbell Scientific PWS100 and two OTT Parsivel2 instruments). The campaign took place in January-February 2016 in the Paris area (France). Disdrometers provide access to information on the size and velocity of drops falling through the sampling area of the devices of roughly a few tens of cm2. It enables the drop size distribution to be estimated and rainfall microphysics, kinetic energy, or radar quantities, for example, to be studied further. Raw data, i.e. basically a matrix containing a number of drops according to classes of size and velocity, along with more aggregated ones, such as the rain rate or drop size distribution with filtering, are available. Link to the data set: https://zenodo.org/record/1240168 (DOI: https://doi.org/10.5281/zenodo.1240168).
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NASA Astrophysics Data System (ADS)
Zakaria, Rozalina; Noh, Siti Munirah Che; Petković, Dalibor; Shamshirband, Shahaboddin; Penny, Richard
2014-09-01
This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor. After a thorough investigation, the Editor has concluded that the acceptance of this article was based upon the positive advice of at least one faked reviewer report. The report was submitted from a fictitious email account which was provided to the journal as a suggested reviewer by the corresponding author during the submission of the paper. This manipulation of the peer-review process represents a clear violation of the fundamentals of peer review, our publishing policies, and publishing ethics standards. Apologies are offered to the readers of the journal that this deception was not detected during the submission process. Section 3 of the article plagiarizes part of the text that appeared in the article published by R. Maity et al in Hydrological Processes 24 (2010) 917-923, http://dx.doi.org/10.1002/hyp.7535. The article also duplicates parts of the articles previously published by the authors in the Journal of the Optical Society of America A 31 (2014) 1023-1030, http://dx.doi.org/10.1364/JOSAA.31.001023, Infrared Physics & Technology 65 (2014) 94-102, http://dx.doi.org/10.1016/j.infrared.2014.04.005 and Plasmonics 9 (2014) 1189-1196, http://dx.doi.org/10.1007/s11468-014-9730-3.
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Spin-Orbit Coupled Bose-Einstein Condensates
2016-11-03
generalized the new concepts to interacting spin-1/2 bosons in optical lattices and described a superfluid-to-Mott insulator transition in spin-orbit...and quantum phase transitions in topological insulators , Physical Review B, (09 2010): 0. doi: 10.1103/PhysRevB.82.115125 Christopher Varney, Kai...109.235308 J. Radi?, A. Di Ciolo, K. Sun, V. Galitski. Exotic Quantum Spin Models in Spin-Orbit-Coupled Mott Insulators , Physical Review Letters
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Simulation of Quantum Phenomena in Nanowire Sensors
2014-12-17
Ag and Pt atoms: search for nanocatalysts, Journal of Physics B: Atomic, Molecular and Optical Physics, (07 2011): 0. doi: 10.1088/0953- 4075/44...International Advisory Committee, African Laser Centre Annual Workshop 3-5 Nov. 2014, Moroccan Foundation for Advanced Science, Innovation & Research...atoms encapsulated inside C180 and C240 we found: 1) The Xe-C180 and Xe-C240 binding energies along some high symmetry directions showed the
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Ultrafast Laser Interaction Processes for Libs and Other Sensing Technologies
2013-04-05
Wang. Propagation of ultrashort pulses through water, Optics Express, (02 2007): . doi: 12/02/2009 8.00 Z. Chen, S. Mao. Femtosecond laser -induced...Richardson, "Nd:YAG-CO2 double- pulse laser -induced breakdown spectroscopy for explosive residues detection" SPIE Defense, Security, Sensing; Orlando, FL... Ultrashort Pulse Laser Workshop, Directed Energy Professional Society; Newton, MA, USA; 06/29,2009. 63. Martin C. Richardson, Michael Sigman
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Ultrafast Laser Interaction Processes for LIBS and Other Sensing Technologies
2013-04-05
Propagation of ultrashort pulses through water, Optics Express, (02 2007): . doi: 12/02/2009 8.00 Z. Chen, S. Mao. Femtosecond laser -induced electronic...CO2 double- pulse laser -induced breakdown spectroscopy for explosive residues detection" SPIE Defense, Security, Sensing; Orlando, FL, USA; 04/07...Matthieu Baudelet, Michael Sigman, Paul J Dagdigian, Martin C. Richardson, "Nd:YAG-CO2 Double- Pulse Laser Induced Breakdown Spectroscopy for Explosive
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Robust Multi Sensor Classification via Jointly Sparse Representation
2016-03-14
rank, sensor network, dictionary learning REPORT DOCUMENTATION PAGE 11. SPONSOR/MONITOR’S REPORT NUMBER(S) 10. SPONSOR/MONITOR’S ACRONYM(S) ARO 8...with ultrafast laser pulses, Optics Express, (04 2015): 10521. doi: Xiaoxia Sun, Nasser M. Nasrabadi, Trac D. Tran. Task-Driven Dictionary Learning...in dictionary design, compressed sensors design, and optimization in sparse recovery also helps. We are able to advance the state of the art
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NASA Astrophysics Data System (ADS)
Huang, Tao; Browning, Lauren M.; Xu, Xiao-Hong Nancy
2012-04-01
Cellular signaling pathways play crucial roles in cellular functions and design of effective therapies. Unfortunately, study of cellular signaling pathways remains formidably challenging because sophisticated cascades are involved, and a few molecules are sufficient to trigger signaling responses of a single cell. Here we report the development of far-field photostable-optical-nanoscopy (PHOTON) with photostable single-molecule-nanoparticle-optical-biosensors (SMNOBS) for mapping dynamic cascades of apoptotic signaling pathways of single live cells in real-time at single-molecule (SM) and nanometer (nm) resolutions. We have quantitatively imaged single ligand molecules (tumor necrosis factor α, TNFα) and their binding kinetics with their receptors (TNFR1) on single live cells; tracked formation and internalization of their clusters and their initiation of intracellular signaling pathways in real-time; and studied apoptotic signaling dynamics and mechanisms of single live cells with sufficient temporal and spatial resolutions. This study provides new insights into complex real-time dynamic cascades and molecular mechanisms of apoptotic signaling pathways of single live cells. PHOTON provides superior imaging and sensing capabilities and SMNOBS offer unrivaled biocompatibility and photostability, which enable probing of signaling pathways of single live cells in real-time at SM and nm resolutions.Cellular signaling pathways play crucial roles in cellular functions and design of effective therapies. Unfortunately, study of cellular signaling pathways remains formidably challenging because sophisticated cascades are involved, and a few molecules are sufficient to trigger signaling responses of a single cell. Here we report the development of far-field photostable-optical-nanoscopy (PHOTON) with photostable single-molecule-nanoparticle-optical-biosensors (SMNOBS) for mapping dynamic cascades of apoptotic signaling pathways of single live cells in real-time at single-molecule (SM) and nanometer (nm) resolutions. We have quantitatively imaged single ligand molecules (tumor necrosis factor α, TNFα) and their binding kinetics with their receptors (TNFR1) on single live cells; tracked formation and internalization of their clusters and their initiation of intracellular signaling pathways in real-time; and studied apoptotic signaling dynamics and mechanisms of single live cells with sufficient temporal and spatial resolutions. This study provides new insights into complex real-time dynamic cascades and molecular mechanisms of apoptotic signaling pathways of single live cells. PHOTON provides superior imaging and sensing capabilities and SMNOBS offer unrivaled biocompatibility and photostability, which enable probing of signaling pathways of single live cells in real-time at SM and nm resolutions. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr11739h
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Roncali, Emilie; Schmall, Jeffrey P.; Viswanath, Varsha; Berg, Eric; Cherry, Simon R.
2014-01-01
Current developments in positron emission tomography (PET) focus on improving timing performance for scanners with time-of-flight (TOF) capability, and incorporating depth-of-interaction (DOI) information. Recent studies have shown that incorporating DOI correction in TOF detectors can improve timing resolution, and that DOI also becomes more important in long axial field-of-view scanners. We have previously reported the development of DOI-encoding detectors using phosphor-coated scintillation crystals; here we study the timing properties of those crystals to assess the feasibility of providing some level of DOI information without significantly degrading the timing performance. We used Monte Carlo simulations to provide a detailed understanding of light transport in phosphor-coated crystals which cannot be fully characterized experimentally. Our simulations used a custom reflectance model based on 3D crystal surface measurements. Lutetium oxyorthosilicate (LSO) crystals were simulated with a phosphor coating in contact with the scintillator surfaces and an external diffuse reflector (teflon). Light output, energy resolution, and pulse shape showed excellent agreement with experimental data obtained on 3 × 3 × 10 mm3 crystals coupled to a photomultiplier tube (PMT). Scintillator intrinsic timing resolution was simulated with head-on and side-on configurations, confirming the trends observed experimentally. These results indicate that the model may be used to predict timing properties in phosphor-coated crystals and guide the coating for optimal DOI resolution/timing performance trade-off for a given crystal geometry. Simulation data suggested that a time stamp generated from early photoelectrons minimizes degradation of the timing resolution, thus making this method potentially more useful for TOF-DOI detectors than our initial experiments suggested. Finally, this approach could easily be extended to the study of timing properties in other scintillation crystals, with a range of treatments and materials attached to the surface. PMID:24694727
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Bull, Eleanor J; Porkess, Veronica; Rigby, Michael; Hutson, Peter H; Fone, Kevin C F
2006-03-01
The current study examined the long-term effect of brief exposure to 3,4-methylenedioxymethamphetamine (MDMA) on local cerebral glucose utilization (LCGU) in specific brain regions immediately following administration of the 5-HT2A/2C receptor agonist, 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI). Wistar rats (post-natal day (PND) 28, n = 24) were administered MDMA (5 mg/kg, i.p.) or saline (1 ml/kg, i.p.) four times daily for 2 consecutive days and core body temperature was recorded. Fifty-five days later and 10 min following injection of DOI (1 mg/kg, i.p.) or saline, LCGU was measured using the [14C]2-deoxyglucose (2-DG) technique. In the 4 hours following the initial injection (PND 28), MDMA-treated rats exhibited significant hyperthermia compared with saline-treated controls (p < 0.05-0.01). Eight weeks later, immediately following DOI challenge, LCGU was significantly elevated (an increase of 47%, p < 0.05) in the nucleus accumbens of MDMA/DOI pretreated rats, compared with that in MDMA/saline pre-treated controls. A similar trend was observed in other areas such as the lateral habenula, somatosensory cortex and hippocampal regions (percentage changes of 27-41%), but these did not reach significance. Blood glucose levels were significantly elevated in both groups of DOI-treated rats (p < 0.05-0.01). Thus, brief exposure of young rats to an MDMA regimen previously shown to cause anxiety-like behaviour and modest serotonergic neurotoxicity (Bull et al., 2004) increased DOI-induced energy metabolism in the nucleus accumbens and tended to increase metabolism in other brain regions, including the hippocampus, consistent with the induction of long-term brain region specific changes in synaptic plasticity.
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The integrated water balance and soil data set of the Rollesbroich hydrological observatory
NASA Astrophysics Data System (ADS)
Qu, Wei; Bogena, Heye R.; Huisman, Johan A.; Schmidt, Marius; Kunkel, Ralf; Weuthen, Ansgar; Schiedung, Henning; Schilling, Bernd; Sorg, Jürgen; Vereecken, Harry
2016-10-01
The Rollesbroich headwater catchment located in western Germany is a densely instrumented hydrological observatory and part of the TERENO (Terrestrial Environmental Observatories) initiative. The measurements acquired in this observatory present a comprehensive data set that contains key hydrological fluxes in addition to important hydrological states and properties. Meteorological data (i.e., precipitation, air temperature, air humidity, radiation components, and wind speed) are continuously recorded and actual evapotranspiration is measured using the eddy covariance technique. Runoff is measured at the catchment outlet with a gauging station. In addition, spatiotemporal variations in soil water content and temperature are measured at high resolution with a wireless sensor network (SoilNet). Soil physical properties were determined using standard laboratory procedures from samples taken at a large number of locations in the catchment. This comprehensive data set can be used to validate remote sensing retrievals and hydrological models, to improve the understanding of spatial temporal dynamics of soil water content, to optimize data assimilation and inverse techniques for hydrological models, and to develop upscaling and downscaling procedures of soil water content information. The complete data set is freely available online (http://www.tereno.net, doi:10.5880/TERENO.2016.001, doi:10.5880/TERENO.2016.004, doi:10.5880/TERENO.2016.003) and additionally referenced by three persistent identifiers securing the long-term data and metadata availability.
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Drought Risk and Adaptation in the Interior (DRAI)
NASA Astrophysics Data System (ADS)
McNeeley, S.; Ojima, D. S.
2013-12-01
Drought is part of the normal climate variability in the Great Plains and Intermountain Western United States, but recent severe droughts along with climate change projections have increased the interest and need for better understanding of drought science and decision making. The purpose of this study is to understand how the U.S. Department of the Interior's (DOI) federal land and resource managers and their stakeholders (i.e., National Park Service, Bureau of Land Management, Fish and Wildlife Service, Bureau of Reclamation, Bureau of Indian Affairs and tribes, among others) are experiencing and dealing with drought in their landscapes. The Drought Risk and Adaptation in the Interior (DRAI) project is part of a new DOI-sponsored North Central Climate Science Center (NC CSC) crosscutting science initiative on drought across the Center's three foundational science areas: 1. physical climate, 2. ecosystems impacts and responses, and 3. human adaptation and decision making. The overarching goal is to learn more about drought within the DOI public lands and resource management in order to contribute to both the NC CSC regional science as well as providing managers and other decision makers with the most salient, credible, and legitimate research to support land and resource management decisions. Here we will present the project approach along with some initial insights learned from the research to date along with its utility for climate adaptation.
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Spectral reflectance data of a high temperature stable solar selective coating based on MoSi2–Si3N4
Hernández-Pinilla, D.; Rodríguez-Palomo, A.; Álvarez-Fraga, L.; Céspedes, E.; Prieto, J.E.; Muñoz-Martín, A.; Prieto, C.
2016-01-01
Data of optical performance, thermal stability and ageing are given for solar selective coatings (SSC) based on a novel MoSi2–Si3N4 absorbing composite. SSC have been prepared as multilayer stacks formed by silver as metallic infrared reflector, a double layer composite and an antireflective layer (doi: 10.1016/j.solmat.2016.04.001 [1]). Spectroscopic reflectance data corresponding to the optical performance of samples after moderate vacuum annealing at temperatures up to 600 °C and after ageing test of more than 200 h with several heating–cooling cycles are shown here. PMID:27182544
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Direct neural pathways convey distinct visual information to Drosophila mushroom bodies
Vogt, Katrin; Aso, Yoshinori; Hige, Toshihide; Knapek, Stephan; Ichinose, Toshiharu; Friedrich, Anja B; Turner, Glenn C; Rubin, Gerald M; Tanimoto, Hiromu
2016-01-01
Previously, we demonstrated that visual and olfactory associative memories of Drosophila share mushroom body (MB) circuits (Vogt et al., 2014). Unlike for odor representation, the MB circuit for visual information has not been characterized. Here, we show that a small subset of MB Kenyon cells (KCs) selectively responds to visual but not olfactory stimulation. The dendrites of these atypical KCs form a ventral accessory calyx (vAC), distinct from the main calyx that receives olfactory input. We identified two types of visual projection neurons (VPNs) directly connecting the optic lobes and the vAC. Strikingly, these VPNs are differentially required for visual memories of color and brightness. The segregation of visual and olfactory domains in the MB allows independent processing of distinct sensory memories and may be a conserved form of sensory representations among insects. DOI: http://dx.doi.org/10.7554/eLife.14009.001 PMID:27083044
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Automated deep-phenotyping of the vertebrate brain
Allalou, Amin; Wu, Yuelong; Ghannad-Rezaie, Mostafa; Eimon, Peter M; Yanik, Mehmet Fatih
2017-01-01
Here, we describe an automated platform suitable for large-scale deep-phenotyping of zebrafish mutant lines, which uses optical projection tomography to rapidly image brain-specific gene expression patterns in 3D at cellular resolution. Registration algorithms and correlation analysis are then used to compare 3D expression patterns, to automatically detect all statistically significant alterations in mutants, and to map them onto a brain atlas. Automated deep-phenotyping of a mutation in the master transcriptional regulator fezf2 not only detects all known phenotypes but also uncovers important novel neural deficits that were overlooked in previous studies. In the telencephalon, we show for the first time that fezf2 mutant zebrafish have significant patterning deficits, particularly in glutamatergic populations. Our findings reveal unexpected parallels between fezf2 function in zebrafish and mice, where mutations cause deficits in glutamatergic neurons of the telencephalon-derived neocortex. DOI: http://dx.doi.org/10.7554/eLife.23379.001 PMID:28406399
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NASA Astrophysics Data System (ADS)
Stengel, Martin; Stapelberg, Stefan; Sus, Oliver; Schlundt, Cornelia; Poulsen, Caroline; Thomas, Gareth; Christensen, Matthew; Carbajal Henken, Cintia; Preusker, Rene; Fischer, Jürgen; Devasthale, Abhay; Willén, Ulrika; Karlsson, Karl-Göran; McGarragh, Gregory R.; Proud, Simon; Povey, Adam C.; Grainger, Roy G.; Fokke Meirink, Jan; Feofilov, Artem; Bennartz, Ralf; Bojanowski, Jedrzej S.; Hollmann, Rainer
2017-11-01
New cloud property datasets based on measurements from the passive imaging satellite sensors AVHRR, MODIS, ATSR2, AATSR and MERIS are presented. Two retrieval systems were developed that include components for cloud detection and cloud typing followed by cloud property retrievals based on the optimal estimation (OE) technique. The OE-based retrievals are applied to simultaneously retrieve cloud-top pressure, cloud particle effective radius and cloud optical thickness using measurements at visible, near-infrared and thermal infrared wavelengths, which ensures spectral consistency. The retrieved cloud properties are further processed to derive cloud-top height, cloud-top temperature, cloud liquid water path, cloud ice water path and spectral cloud albedo. The Cloud_cci products are pixel-based retrievals, daily composites of those on a global equal-angle latitude-longitude grid, and monthly cloud properties such as averages, standard deviations and histograms, also on a global grid. All products include rigorous propagation of the retrieval and sampling uncertainties. Grouping the orbital properties of the sensor families, six datasets have been defined, which are named AVHRR-AM, AVHRR-PM, MODIS-Terra, MODIS-Aqua, ATSR2-AATSR and MERIS+AATSR, each comprising a specific subset of all available sensors. The individual characteristics of the datasets are presented together with a summary of the retrieval systems and measurement records on which the dataset generation were based. Example validation results are given, based on comparisons to well-established reference observations, which demonstrate the good quality of the data. In particular the ensured spectral consistency and the rigorous uncertainty propagation through all processing levels can be considered as new features of the Cloud_cci datasets compared to existing datasets. In addition, the consistency among the individual datasets allows for a potential combination of them as well as facilitates studies on the impact of temporal sampling and spatial resolution on cloud climatologies.
For each dataset a digital object identifier has been issued:
Cloud_cci AVHRR-AM: https://doi.org/10.5676/DWD/ESA_Cloud_cci/AVHRR-AM/V002
Cloud_cci AVHRR-PM: https://doi.org/10.5676/DWD/ESA_Cloud_cci/AVHRR-PM/V002
Cloud_cci MODIS-Terra: https://doi.org/10.5676/DWD/ESA_Cloud_cci/MODIS-Terra/V002
Cloud_cci MODIS-Aqua: https://doi.org/10.5676/DWD/ESA_Cloud_cci/MODIS-Aqua/V002
Cloud_cci ATSR2-AATSR: https://doi.org/10.5676/DWD/ESA_Cloud_cci/ATSR2-AATSR/V002
Cloud_cci MERIS+AATSR: https://doi.org/10.5676/DWD/ESA_Cloud_cci/MERIS+AATSR/V002
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NASA Astrophysics Data System (ADS)
Ito, Mikiko; Lee, Jae Sung; Park, Min-Jae; Sim, Kwang-Souk; Jong Hong, Seong
2010-07-01
PET detectors with depth-of-interaction (DOI) encoding capability allow high spatial resolution and high sensitivity to be achieved simultaneously. To obtain DOI information from a mono-layer array of scintillation crystals using a single-ended readout, the authors devised a method based on light spreading within a crystal array and performed Monte Carlo simulations with individual scintillation photon tracking to prove the concept. A scintillation crystal array model was constructed using a grid method. Conventional grids are constructed using comb-shaped reflector strips with rectangular teeth to isolate scintillation crystals optically. However, the authors propose the use of triangularly shaped teeth, such that scintillation photons spread only in the x-direction in the upper halves of crystals and in the y-direction in lower halves. DOI positions can be estimated by considering the extent of two-dimensional light dispersion, which can be determined from the multiple anode outputs of a position-sensitive PMT placed under the crystal array. In the main simulation, a crystal block consisting of a 29 × 29 array of 1.5 mm × 1.5 mm × 20 mm crystals and a multi-anode PMT with 16 × 16 pixels were used. The effects of crystal size and non-uniform PMT output gain were also explored by simulation. The DOI resolution estimated for 1.5 × 1.5 × 20 mm3 crystals was 2.16 mm on average. Although the flood map was depth dependent, each crystal was well identified at all depths when a corner of the crystal array was irradiated with 511 keV gamma rays (peak-to-valley ratio ~9:1). DOI resolution was better than 3 mm up to a crystal length of 28 mm with a 1.5 × 1.5 mm2 or 2.0 × 2.0 mm2 crystal surface area. The devised light-sharing method allowed excellent DOI resolutions to be obtained without the use of dual-ended readout or multiple crystal arrays.
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The Exile of Hansen's Disease Patients to Moloka'i: A Diffusion of Innovations Perspective.
Pitman Harris, Adrea; Matusitz, Jonathan
2016-07-01
This article analyzes the exile of patients with Hansen's disease (leprosy) to Moloka'i (Hawaii) by applying the diffusion of innovations (DoI) theory. Developed by Rogers, DoI posits that an innovation (i.e., idea, movement, or trend) is initiated within a culture. Then, it is diffused via particular channels across diverse cultures. Instead of evolving independently, innovations diffuse from one culture to another through various forms of contact and communication. In the context of this analysis, the objective is to examine how the diffusion of certain ideas, namely, abolishing the stigma associated with leprosy, could have improved the lives of Hawaiians. An important premise of this article is that the Hawaiian government barely applied the tenets of DoI, which is the reason why many people lost their lives. So, this article seeks to explore what could have been done to improve their situation and what pitfalls should be avoided in the future.
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Submesoscale Routes to Lateral Mixing in the Ocean
2013-09-30
onset of restratification by mixed layer eddies, and find this to be coincident with the onset of the spring phytoplankton bloom (Mahadevan et al...Perry, Eddy- driven stratification initiates North Atlantic spring phytoplankton blooms, 2012, Science, 337 (6090), 54-58, DOI:10.1126/science.1218740
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A common mechanism underlies changes of mind about decisions and confidence
van den Berg, Ronald; Anandalingam, Kavitha; Zylberberg, Ariel; Kiani, Roozbeh; Shadlen, Michael N; Wolpert, Daniel M
2016-01-01
Decisions are accompanied by a degree of confidence that a selected option is correct. A sequential sampling framework explains the speed and accuracy of decisions and extends naturally to the confidence that the decision rendered is likely to be correct. However, discrepancies between confidence and accuracy suggest that confidence might be supported by mechanisms dissociated from the decision process. Here we show that this discrepancy can arise naturally because of simple processing delays. When participants were asked to report choice and confidence simultaneously, their confidence, reaction time and a perceptual decision about motion were explained by bounded evidence accumulation. However, we also observed revisions of the initial choice and/or confidence. These changes of mind were explained by a continuation of the mechanism that led to the initial choice. Our findings extend the sequential sampling framework to vacillation about confidence and invites caution in interpreting dissociations between confidence and accuracy. DOI: http://dx.doi.org/10.7554/eLife.12192.001 PMID:26829590
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Ebola virus disease in the Democratic Republic of the Congo, 1976-2014
Rosello, Alicia; Mossoko, Mathias; Flasche, Stefan; Van Hoek, Albert Jan; Mbala, Placide; Camacho, Anton; Funk, Sebastian; Kucharski, Adam; Ilunga, Benoit Kebela; Edmunds, W John; Piot, Peter; Baguelin, Marc; Muyembe Tamfum, Jean-Jacques
2015-01-01
The Democratic Republic of the Congo has experienced the most outbreaks of Ebola virus disease since the virus' discovery in 1976. This article provides for the first time a description and a line list for all outbreaks in this country, comprising 996 cases. Compared to patients over 15 years old, the odds of dying were significantly lower in patients aged 5 to 15 and higher in children under five (with 100% mortality in those under 2 years old). The odds of dying increased by 11% per day that a patient was not hospitalised. Outbreaks with an initially high reproduction number, R (>3), were rapidly brought under control, whilst outbreaks with a lower initial R caused longer and generally larger outbreaks. These findings can inform the choice of target age groups for interventions and highlight the importance of both reducing the delay between symptom onset and hospitalisation and rapid national and international response. DOI: http://dx.doi.org/10.7554/eLife.09015.001 PMID:26525597
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Gupta, Tripti; Kumar, Arun; Cattenoz, Pierre B.; VijayRaghavan, K; Giangrande, Angela
2016-01-01
Collective migration is a complex process that contributes to build precise tissue and organ architecture. Several molecules implicated in cell interactions also control collective migration, but their precise role and the finely tuned expression that orchestrates this complex developmental process are poorly understood. Here, we show that the timely and threshold expression of the Netrin receptor Frazzled triggers the initiation of glia migration in the developing Drosophila wing. Frazzled expression is induced by the transcription factor Glide/Gcm in a dose-dependent manner. Thus, the glial determinant also regulates the efficiency of collective migration. NetrinB but not NetrinA serves as a chemoattractant and Unc5 contributes as a repellant Netrin receptor for glia migration. Our model includes strict spatial localization of a ligand, a cell autonomously acting receptor and a fate determinant that act coordinately to direct glia toward their final destination. DOI: http://dx.doi.org/10.7554/eLife.15983.001 PMID:27740455
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Ferrin, Michael A; Subramaniam, Arvind R
2017-01-01
Ribosome stalling on mRNAs can decrease protein expression. To decipher ribosome kinetics at stall sites, we induced ribosome stalling at specific codons by starving the bacterium Escherichia coli for the cognate amino acid. We measured protein synthesis rates from a reporter library of over 100 variants that encoded systematic perturbations of translation initiation rate, the number of stall sites, and the distance between stall sites. Our measurements are quantitatively inconsistent with two widely-used kinetic models for stalled ribosomes: ribosome traffic jams that block initiation, and abortive (premature) termination of stalled ribosomes. Rather, our measurements support a model in which collision with a trailing ribosome causes abortive termination of the stalled ribosome. In our computational analysis, ribosome collisions selectively stimulate abortive termination without fine-tuning of kinetic rate parameters at ribosome stall sites. We propose that ribosome collisions serve as a robust timer for translational quality control pathways to recognize stalled ribosomes. DOI: http://dx.doi.org/10.7554/eLife.23629.001 PMID:28498106
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Devlin, Rebecca; Marques, Catarina A; Paape, Daniel; Prorocic, Marko; Zurita-Leal, Andrea C; Campbell, Samantha J; Lapsley, Craig; Dickens, Nicholas; McCulloch, Richard
2016-01-01
Survival of Trypanosoma brucei depends upon switches in its protective Variant Surface Glycoprotein (VSG) coat by antigenic variation. VSG switching occurs by frequent homologous recombination, which is thought to require locus-specific initiation. Here, we show that a RecQ helicase, RECQ2, acts to repair DNA breaks, including in the telomeric site of VSG expression. Despite this, RECQ2 loss does not impair antigenic variation, but causes increased VSG switching by recombination, arguing against models for VSG switch initiation through direct generation of a DNA double strand break (DSB). Indeed, we show DSBs inefficiently direct recombination in the VSG expression site. By mapping genome replication dynamics, we reveal that the transcribed VSG expression site is the only telomeric site that is early replicating – a differential timing only seen in mammal-infective parasites. Specific association between VSG transcription and replication timing reveals a model for antigenic variation based on replication-derived DNA fragility. DOI: http://dx.doi.org/10.7554/eLife.12765.001 PMID:27228154
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Shaheen, Samina; Wan, Zhengpeng; Li, Zongyu; Chau, Alicia; Li, Xinxin; Zhang, Shaosen; Liu, Yang; Yi, Junyang; Zeng, Yingyue; Wang, Jing; Chen, Xiangjun; Xu, Liling; Chen, Wei; Wang, Fei; Lu, Yun; Zheng, Wenjie; Shi, Yan; Sun, Xiaolin; Li, Zhanguo; Xiong, Chunyang; Liu, Wanli
2017-01-01
The mechanosensing ability of lymphocytes regulates their activation in response to antigen stimulation, but the underlying mechanism remains unexplored. Here, we report that B cell mechanosensing-governed activation requires BCR signaling molecules. PMA-induced activation of PKCβ can bypass the Btk and PLC-γ2 signaling molecules that are usually required for B cells to discriminate substrate stiffness. Instead, PKCβ-dependent activation of FAK is required, leading to FAK-mediated potentiation of B cell spreading and adhesion responses. FAK inactivation or deficiency impaired B cell discrimination of substrate stiffness. Conversely, adhesion molecules greatly enhanced this capability of B cells. Lastly, B cells derived from rheumatoid arthritis (RA) patients exhibited an altered BCR response to substrate stiffness in comparison with healthy controls. These results provide a molecular explanation of how initiation of B cell activation discriminates substrate stiffness through a PKCβ-mediated FAK activation dependent manner. DOI: http://dx.doi.org/10.7554/eLife.23060.001 PMID:28755662
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Meyer, Heather M; Teles, José; Formosa-Jordan, Pau; Refahi, Yassin; San-Bento, Rita; Ingram, Gwyneth; Jönsson, Henrik; Locke, James C W; Roeder, Adrienne H K
2017-01-01
Multicellular development produces patterns of specialized cell types. Yet, it is often unclear how individual cells within a field of identical cells initiate the patterning process. Using live imaging, quantitative image analyses and modeling, we show that during Arabidopsis thaliana sepal development, fluctuations in the concentration of the transcription factor ATML1 pattern a field of identical epidermal cells to differentiate into giant cells interspersed between smaller cells. We find that ATML1 is expressed in all epidermal cells. However, its level fluctuates in each of these cells. If ATML1 levels surpass a threshold during the G2 phase of the cell cycle, the cell will likely enter a state of endoreduplication and become giant. Otherwise, the cell divides. Our results demonstrate a fluctuation-driven patterning mechanism for how cell fate decisions can be initiated through a random yet tightly regulated process. DOI: http://dx.doi.org/10.7554/eLife.19131.001 PMID:28145865
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Active suppression of a leaf meristem orchestrates determinate leaf growth
Alvarez, John Paul; Furumizu, Chihiro; Efroni, Idan; Eshed, Yuval; Bowman, John L
2016-01-01
Leaves are flat determinate organs derived from indeterminate shoot apical meristems. The presence of a specific leaf meristem is debated, as anatomical features typical of meristems are not present in leaves. Here we demonstrate that multiple NGATHA (NGA) and CINCINNATA-class-TCP (CIN-TCP) transcription factors act redundantly, shortly after leaf initiation, to gradually restrict the activity of a leaf meristem in Arabidopsis thaliana to marginal and basal domains, and that their absence confers persistent marginal growth to leaves, cotyledons and floral organs. Following primordia initiation, the restriction of the broadly acting leaf meristem to the margins is mediated by the juxtaposition of adaxial and abaxial domains and maintained by WOX homeobox transcription factors, whereas other marginal elaboration genes are dispensable for its maintenance. This genetic framework parallels the morphogenetic program of shoot apical meristems and may represent a relic of an ancestral shoot system from which seed plant leaves evolved. DOI: http://dx.doi.org/10.7554/eLife.15023.001 PMID:27710768
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Lalu, Manoj M; Sullivan, Katrina J; Mei, Shirley HJ; Moher, David; Straus, Alexander; Fergusson, Dean A; Stewart, Duncan J; Jazi, Mazen; MacLeod, Malcolm; Winston, Brent; Marshall, John; Hutton, Brian; Walley, Keith R; McIntyre, Lauralyn
2016-01-01
Evaluation of preclinical evidence prior to initiating early-phase clinical studies has typically been performed by selecting individual studies in a non-systematic process that may introduce bias. Thus, in preparation for a first-in-human trial of mesenchymal stromal cells (MSCs) for septic shock, we applied systematic review methodology to evaluate all published preclinical evidence. We identified 20 controlled comparison experiments (980 animals from 18 publications) of in vivo sepsis models. Meta-analysis demonstrated that MSC treatment of preclinical sepsis significantly reduced mortality over a range of experimental conditions (odds ratio 0.27, 95% confidence interval 0.18–0.40, latest timepoint reported for each study). Risk of bias was unclear as few studies described elements such as randomization and no studies included an appropriately calculated sample size. Moreover, the presence of publication bias resulted in a ~30% overestimate of effect and threats to validity limit the strength of our conclusions. This novel prospective application of systematic review methodology serves as a template to evaluate preclinical evidence prior to initiating first-in-human clinical studies. DOI: http://dx.doi.org/10.7554/eLife.17850.001 PMID:27870924
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Effects of fixture rotation on coating uniformity for high-performance optical filter fabrication
NASA Astrophysics Data System (ADS)
Rubin, Binyamin; George, Jason; Singhal, Riju
2018-04-01
Coating uniformity is critical in fabricating high-performance optical filters by various vacuum deposition methods. Simple and planetary rotation systems with shadow masks are used to achieve the required uniformity [J. B. Oliver and D. Talbot, Appl. Optics 45, 13, 3097 (2006); O. Lyngnes, K. Kraus, A. Ode and T. Erguder, in `Method for Designing Coating Thickness Uniformity Shadow Masks for Deposition Systems with a Planetary Fixture', 2014 Technical Conference Proceedings, Optical Coatings, August 13, 2014, DOI: 10.14332/svc14.proc.1817.]. In this work, we discuss the effect of rotation pattern and speed on thickness uniformity in an ion beam sputter deposition system. Numerical modeling is used to determine statistical distribution of random thickness errors in coating layers. The relationship between thickness tolerance and production yield are simulated theoretically and demonstrated experimentally. Production yields for different optical filters produced in an ion beam deposition system with planetary rotation are presented. Single-wavelength and broadband optical monitoring systems were used for endpoint monitoring during filter deposition. Limitations of thickness tolerances that can be achieved in systems with planetary rotation are shown. Paths for improving production yield in an ion beam deposition system are described.
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NASA Astrophysics Data System (ADS)
Khachatryan, A. G.; van Goor, F. A.; Boller, K.-J.; Reitsma, A. J.; Jaroszynski, D. A.
2004-12-01
Recently a new electron-bunch injection scheme for the laser wakefield accelerator has been proposed [
JETP Lett. 74, 371 (2001) ;JTPLA2 0021-3640 10.1134/1.1427124 Phys. Rev. E 65, 046504 (2002) ]. In this scheme, a low energy electron bunch, sent in a plasma channel just before a high-intensity laser pulse, is trapped in the laser wakefield, considerably compressed and accelerated to an ultrarelativistic energy. In this paper we show the possibility of the generation of an extremely short (on the order of 1 μm long or a few femtoseconds in duration) relativistic-electron-bunch by this mechanism. The initial electron bunch, which can be generated, for example, by a laser-driven photocathode rf gun, should have an energy of a few hundred keVs to a few MeVs, a duration in the picosecond range or less and a relatively low concentration. The trapping conditions and parameters of an accelerated bunch are investigated. The laser pulse dynamics as well as a possible experimental setup for the demonstration of the injection scheme are also considered.PLEEE8 1063-651X 10.1103/PhysRevE.65.046504 -
Origins and demonstrations of electrons with orbital angular momentum
Agrawal, Amit; Ercius, Peter A.; Grillo, Vincenzo; Herzing, Andrew A.; Harvey, Tyler R.; Linck, Martin; Pierce, Jordan S.
2017-01-01
The surprising message of Allen et al. (Allen et al. 1992 Phys. Rev. A 45, 8185 (doi:10.1103/PhysRevA.45.8185)) was that photons could possess orbital angular momentum in free space, which subsequently launched advancements in optical manipulation, microscopy, quantum optics, communications, many more fields. It has recently been shown that this result also applies to quantum mechanical wave functions describing massive particles (matter waves). This article discusses how electron wave functions can be imprinted with quantized phase vortices in analogous ways to twisted light, demonstrating that charged particles with non-zero rest mass can possess orbital angular momentum in free space. With Allen et al. as a bridge, connections are made between this recent work in electron vortex wave functions and much earlier works, extending a 175 year old tradition in matter wave vortices. This article is part of the themed issue ‘Optical orbital angular momentum’. PMID:28069765
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Basic performance of Mg co-doped new scintillator used for TOF-DOI-PET systems
NASA Astrophysics Data System (ADS)
Kobayashi, Takahiro; Yamamoto, Seiichi; Okumura, Satoshi; Yeom, Jung Yeol; Kamada, Kei; Yoshikawa, Akira
2017-01-01
Phoswich depth-of-interaction (DOI) detectors utilizing multiple scintillators with different decay time are a useful device for developing a high spatial resolution, high sensitivity PET scanner. However, in order to apply pulse shape discrimination (PSD), there are not many combinations of scintillators for which phoswich technique can be implemented. Ce doped Gd3Ga3Al2O12 (GFAG) is a recently developed scintillator with a fast decay time. This scintillator is similar to Ce doped Gd3Al2Ga3O12 (GAGG), which is a promising scintillator for PET detector with high light yield. By stacking these scintillators, it may be possible to realize a high spatial resolution and high timing resolution phoswich DOI detector. Such phoswich DOI detector may be applied to time-of-flight (TOF) systems with high timing performance. Therefore, in this study, we tested the basic performance of the new scintillator -GFAG for use in a TOF phoswich detector. The measured decay time of a GFAG element of 2.9 mmx2.9 mmx10 mm in dimension, which was optically coupled to a photomultiplier tube (PMT), was faster (66 ns) than that of same sized GAGG (103 ns). The energy resolution of the GFAG element was 5.7% FWHM which was slightly worse than that of GAGG with 4.9% FWHM for 662 keV gamma photons without saturation correction. Then we assembled the GFAG and the GAGG crystals in the depth direction to form a 20 mm long phoswich element (GFAG/GAGG). By pulse shape analysis, the two types of scintillators were clearly resolved. Measured timing resolution of a pair of opposing GFAG/GAGG phoswich scintillator coupled to Silicon Photomultipliers (Si-PM) was good with coincidence resolving time of 466 ps FWHM. These results indicate that the GFAG combined with GAGG can be a candidate for TOF-DOI-PET systems.
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Time-over-threshold for pulse shape discrimination in a time-of-flight phoswich PET detector
Chang, Chen-Ming; Cates, Joshua W.; Levin, Craig S.
2016-01-01
It is well known that a PET detector capable of measuring both photon time-of-flight (TOF) and depth-of-interaction (DOI) improves the image quality and accuracy. Phoswich designs have been realized in PET detectors to measure DOI for more than a decade. However, PET detectors based on phoswich designs put great demand on the readout circuits, which have to differentiate the pulse shape produced by different crystal layers. A simple pulse shape discrimination approach is required to realize the phoswich designs in a clinical PET scanner, which consists of thousands of scintillation crystal elements. In this work, we studied time-over-threshold (ToT) as a pulse shape parameter for DOI. The energy, timing and DOI performance were evaluated for a phoswich detector design comprising 3 mm × 3 mm × 10 mm LYSO:Ce crystal optically coupled to 3 mm × 3 mm × 10 mm calcium co-doped LSO:Ce,Ca(0.4%) crystal read out by a silicon photomultiplier (SiPM). A DOI accuracy of 97.2% has been achieved for photopeak events using the proposed time-over-threshold (ToT) processing. The energy resolution without correction for SiPM non-linearity was 9.7 ± 0.2% and 11.3 ± 0.2% FWHM at 511 keV for LYSO and LSO crystal layers, respectively. The coincidence time resolution for photopeak events ranges from 164.6 ps to 183.1 ps FWHM, depending on the layer combinations. The coincidence time resolution for inter-crystal scatter events ranges from 214.6 ps to 418.3 ps FWHM, depending on the energy windows applied. These results show great promises of using ToT for pulse shape discrimination in a TOF phoswich detector since a ToT measurement can be easily implemented in readout electronics. PMID:27991437
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CLouds, and Aerosols Radiative Impacts and Forcing: Year 2016 (CLARIFY-2016)
NASA Astrophysics Data System (ADS)
Haywood, J. M.; Bellouin, N.; Carslaw, K. S.; Coe, H.; Field, P.; Highwood, E. J.; Redemann, J.; Stier, P.; Wood, R.; Zuidema, P.
2013-12-01
Strongly absorbing biomass burning aerosols (BBAs) exist above highly reflectant stratocumulus clouds in the SE Atlantic with implications on the direct (e.g. Haywood et al., 2003), semi-direct (e.g. Johnson et al., 2006), and indirect effect of aerosols, implications on the remote sensing of cloud optical properties, development of clouds and feedback processes. Here, we present an analysis of modelled estimates of the direct effect using twelve models from the AEROCOM project (Myhre et al., 2013) to show that estimates of the direct effect in SE Atlantic range from strongly negative to strongly positive. Furthermore, we evaluate the performance of the HadGEM2 model and show it cannot replicate the extreme values of positive forcing inferred from high spectral resolution satellite retrievals. By examining patterns of deposition, we infer that the indirect effect from biomass burning aerosols is very limited in the model, but without detailed measurements we are unsure of the validity of this inference. We conclude that the SE Atlantic is therefore of key importance in determining the radiative forcing of biomass burning aerosols and provides a very stringent test for global climate models as they need to accurately represent the geographic distribution of the aerosol optical depth, the wavelength dependent aerosol single scattering albedo, the vertical profile of the aerosol, the geographic distribution of the cloud, the cloud fraction, the cloud liquid water content, the cloud droplet effective radii, and the vertical profile of the cloud. These results are used as scientific rationale to justify a new measurement campaign: CLouds and Aerosol Radiative Impacts and Forcing: Year-2016 (CLARIFY-2016). Haywood, J.M., Osborne, S.R. Francis, P.N., Keil, A., Formenti, P., Andreae, M.O., and Kaye, P.H., The mean physical and optical properties of regional haze dominated by biomass burning aerosol measured from the C-130 aircraft during SAFARI 2000, J. Geophys. Res., 108(D13), 8473, doi:10.1029/2002JD002226, 2003. Johnson, B.T., K.P. Shine, and P.M. Forster, The semi-direct aerosol effect: Impact of absorbing aerosols on marine stratocumulus, QJRMS, DOI: 10.1256/qj.03.61, 2006. Myhre, G. et al. Radiative forcing of the direct aerosol effect from AeroCom Phase II simulations, Atmos. Chem. Phys., 13, 1853-1877, doi:10.5194/acp-13-1853-2013, 2013
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Matter-Wave Optics of Diatomic Molecules
2012-10-23
81.013802 10/11/2012 32.00 Swati Singh , Pierre Meystre. Atomic probe Wigner tomography of a nanomechanical system, Physical Review A, (04 2010): 41804...PhysRevA.78.041801 10/11/2012 3.00 S. Singh , M. Bhattacharya, O. Dutta, P. Meystre. Coupling Nanomechanical Cantilevers to Dipolar Molecules...degenerate matter waves, Physical Review A, (02 2009): 0. doi: 10.1103/PhysRevA.79.023622 10/11/2012 10.00 M. Bhattacharya, S. Singh , P. -L. Giscard
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From Nanoscale Systems to Ultracold Atoms and Molecules, and Back
2016-08-05
H. Jing, C. Raman, P. Meystre. Optical control of a quantum rotor , Physical Review A, (03 2013): 0. doi: 10.1103/PhysRevA.87.031601 Huatang Tan...study of proposed interferometric gravitational wave detectors in the 1970s and 1980s (and which resulted to the first direct detection of...gravitational waves originating from the collision of massive blackholes by the LIGO gravitational wave antennas in 2015.) In parallel to these kilometer-size
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Kwon, Sun Il; Ferri, Alessandro; Gola, Alberto; Berg, Eric; Piemonte, Claudio; Cherry, Simon R.; Roncali, Emilie
2016-01-01
Abstract. Current research in the field of positron emission tomography (PET) focuses on improving the sensitivity of the scanner with thicker detectors, extended axial field-of-view, and time-of-flight (TOF) capability. These create the need for depth-of-interaction (DOI) encoding to correct parallax errors. We have proposed a method to encode DOI using phosphor-coated crystals. Our initial work using photomultiplier tubes (PMTs) demonstrated the possibilities of the proposed method, however, a major limitation of PMTs for this application is poor quantum efficiency in yellow light, corresponding to the wavelengths of the converted light by the phosphor coating. In contrast, the red-green-blue-high-density (RGB-HD) silicon photomultipliers (SiPMs) have a high photon detection efficiency across the visible spectrum. Excellent coincidence resolving time (CRT; <210 ps) was obtained by coupling RGB-HD SiPMs and 3 × 3 × 20 mm3 lutetium fine silicate crystals coated on a third of one of their lateral sides. Events were classified in three DOI bins (∼6.7-mm width) with an average sensitivity of 83.1%. A CRT of ∼200 ps combined with robust DOI encoding is a marked improvement in the phosphor-coated approach that we pioneered. For the first time, we read out these crystals with SiPMs and clearly demonstrated the potential of the RGB-HD SiPMs for this TOF-DOI PET detector. PMID:27921069
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NASA Astrophysics Data System (ADS)
Narvaez, C.; Mendillo, M.; Trovato, J.
2017-12-01
A semi-empirical model of the maximum electron density (Nmax) of the martian ionosphere [MIRI-mark-1](1) was derived from an initial set radar observations by the MEX/MARSIS instrument. To extend the model to full electron density profiles, normalized shapes of Ne(h) from a theoretical model(2) were calibrated by MIRI's Nmax. Subsequent topside ionosphere observations from MAVEN indicated that topside shapes from MEX/MARSIS(3) offered improved morphology. The MEX topside shapes were then merged to the bottomside shapes from the theoretical model. Using a larger set of MEX/MARSIS observations (07/31/2005 - 05/24/2015), a new specification of Nmax as a function of solar zenith angle and solar flux is now used to calibrate the normalized Ne(h) profiles. The MIRI-mark-2 model includes the integral with height of Ne(h) to form total electron content (TEC) values. Validation of the MIRI TEC was accomplished using an independent set of TEC derived from the SHARAD(4) experiment on MRO. (1) M. Mendillo, A. Marusiak, P. Withers, D. Morgan and D. Gurnett, A New Semi-empirical Model of the Peak Electron Density of the Martian Ionosphere, Geophysical Research Letters, 40, 1-5, doi:10.1002/2013GL057631, 2013. (2) Mayyasi, M. and M. Mendillo (2015), Why the Viking descent probes found only one ionospheric layer at Mars, Geophys. Res. Lett., 42, 7359-7365, doi:10.1002/2015GL065575 (3) Němec, F., D. Morgan, D. Gurnett, and D. Andrews (2016), Empirical model of the Martian dayside ionosphere: Effects of crustal magnetic fields and solar ionizing flux at higher altitudes, J. Geophys. Res. Space Physics, 121, 1760-1771, doi:10.1002/2015/A022060.(4) Campbell, B., and T. Watters (2016), Phase compensation of MARSIS subsurface sounding and estimation of ionospheric properties: New insights from SHARAD results, J.Geophys. Res. Planets, 121, 180-193, doi:10.1002/2015JE004917.
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Optically-energized, emp-resistant, fast-acting, explosion initiating device
Benson, David A.; Kuswa, Glenn W.
1987-01-01
Optical energy, provided from a remote user-operated source, is utilized to initially electrically charge a capacitor in a circuit that also contains an explosion initiating transducer in contact with a small explosive train contained in an attachable housing. Additional optical energy is subsequently supplied in a preferred embodiment to an optically responsive phototransistor acting in conjunction with a silicon controlled rectifer to release the stored electrical energy through the explosion initiating transducer to set off the explosive train. All energy transfers between the user and the explosive apparatus, either for charging it up or for setting it off, are conveyed optically and may be accomplished in a single optical fiber with coding to distinguish between specific optical energy transfers and between these and any extraneous signals.
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NASA Technical Reports Server (NTRS)
Dean, Bruce H. (Inventor)
2009-01-01
A method of recovering unknown aberrations in an optical system includes collecting intensity data produced by the optical system, generating an initial estimate of a phase of the optical system, iteratively performing a phase retrieval on the intensity data to generate a phase estimate using an initial diversity function corresponding to the intensity data, generating a phase map from the phase retrieval phase estimate, decomposing the phase map to generate a decomposition vector, generating an updated diversity function by combining the initial diversity function with the decomposition vector, generating an updated estimate of the phase of the optical system by removing the initial diversity function from the phase map. The method may further include repeating the process beginning with iteratively performing a phase retrieval on the intensity data using the updated estimate of the phase of the optical system in place of the initial estimate of the phase of the optical system, and using the updated diversity function in place of the initial diversity function, until a predetermined convergence is achieved.
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NASA Astrophysics Data System (ADS)
Macdonald, A. S.; Barr, S. M.; Miller, B. V.; Reynolds, P. H.; Rhodes, B. P.; Yokart, B.
2010-01-01
The western gneiss belt in northern Thailand is exposed within two overlapping Cenozoic structural domains: the extensional Doi Inthanon metamorphic core complex domain located west of the Chiang Mai basin, and the Mae Ping strike-slip fault domain located west of the Tak batholith. New P- T estimates and U-Pb and 40Ar/ 39Ar age determinations from the Doi Inthanon domain show that the gneiss there records a complex multi-stage history that can be represented by a clockwise P- T- t path. U-Pb zircon and titanite dating of mylonitic calc-silicate gneiss from the Mae Wang area of the complex indicates that the paragneissic sequence experienced high-grade, medium-pressure metamorphism (M1) in the Late Triassic - Early Jurassic (ca. 210 Ma), in good agreement with previously determined zircon ages from the underlying core orthogneiss exposed on Doi Inthanon. Late Cretaceous monazite ages of 84 and 72 Ma reported previously from the core orthogneiss are attributed to a thermal overprint (M2) to upper-amphibolite facies in the sillimanite field. U-Pb zircon and monazite dating of granitic mylonite from the Doi Suthep area of the complex provides an upper age limit of 40 Ma (Late Eocene) for the early stage(s) of development of the actual core complex, by initially ductile, low-angle extensional shearing under lower amphibolite-facies conditions (M3), accompanied by near-isothermal diapiric rise and decompression melting. 40Ar/ 39Ar laserprobe dating of muscovite from both Doi Suthep and Doi Inthanon provided Miocene ages of ca. 26-15 Ma, representing cooling through the ca. 350 °C isotherm and marking late-stage development of the core complex by detachment faulting of the cover rocks and isostatic uplift of the sheared core zone and mantling gneisses in the footwall. Similarities in the thermochronology of high-grade gneisses exposed in the core complex and shear zone domains in the western gneiss belt of northern Thailand (and also in northern Vietnam, Laos, Yunnan, and central Myanmar) suggest a complex regional response to indentation of Southeast Asia by India.
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Unmanned aircraft systems (UAS) activities at the Department of the Interior
Quirk, Bruce K.; Hutt, Michael E.
2014-01-01
The U.S. Department of the Interior (DOI) is responsible for protecting and managing the natural resources and heritage on almost 20% of the land in the United States. The DOI’s mission requires access to remotely sensed data over vast lands, including areas that are remote and potentially dangerous to access. Unmanned Aircraft Systems (UAS) technology has the potential to enable the DOI to be a better steward of the land by: (1) Improving natural hazard forecasting and the analysis of the impacts. (2) Improving the understanding of climate change to better plan for likely impacts. (3) Developing precipitation and evaporation forecasting to better manage water resources. (4) Monitoring Arctic ice change and its impacts on ecosystems, coasts, and transportation. (5) Increasing safety and effectiveness of wildland fire management. (6) Enhancing search and rescue capabilities. (7) Broadening the abilities to monitor environmental or landscape conditions and changes. (8) Better understanding and protecting the Nation’s ecosystems. The initial operational testing and evaluations performed by the DOI have proven that UAS technology can be used to support many of the Department’s activities. UAS technology provides scientists a way to look longer, closer and more frequently at some of Earth’s most remote areas—places that were previously too dangerous or expensive to monitor in detail. The flexibility of operations and relative low cost to purchase and operate Small Unmanned Aerial System (sUAS) enhances the ability to track long-term landscape and environmental change. The initial testing indicates the operational costs are approximately 10% of traditional manned aircraft. In addition, users can quickly assess landscape-altering events such as wildland fires, floods and volcanoes. UAS technology will allow the DOI to do more with less and in the process enhance the Department’s ability to provide unbiased scientific information to help stakeholders make informed decisions. It will also provide a digital baseline record that can be archived and used when monitoring future events or conditions. One possible future scenario has scientists carrying sUAS into the field allowing quick deployment and operation to observe the environment or for emergency response. This scenario could also include a persistent monitoring capability provided by a UAS that can stay airborne over a small geographic area for days or weeks, or possibly longer. While the DOI focus is on sUAS, the Department recognizes that larger UAS systems will also play a role in meeting its mission. The Department anticipates meeting long-duration or specialized acquisition commitments, such as state or national aerial photography, by collaboration with other agencies or through commercial contracts. Even though the DOI continues to evaluate UAS and sensor technology to meet the Department’s mission, some of its bureaus are already moving towards an operational capability. The authors fully anticipate that by 2020 UAS will emerge as one of the primary platforms for DOI remote sensing applications.
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Data DOIs - virtues and weak points from the perspective of the data journal ESSD
NASA Astrophysics Data System (ADS)
Pfeiffenberger, Hans; Carlson, David
2016-04-01
Fundamentally, data publication seeks to provide improved access, trust and utility for data users accompanied by improved recognition for data providers. The features of persistent identifier schemes used in this context and the policies of providers of their resolver systems can greatly contribute towards these aims! Unfortunately, we also recognize situations where identifier systems undermine some of our lofty data publication aims. From our 7 years of successful experience with the data journal ESSD, we will present our practical observations as well as future requirements on the DOI-system in particular, such as: * Most scientists contributing to or drawing benefit from ESSD seem to understand the notion of published data in the sense of a static, citable entity to build on, relying on its long term availability and integrity (as is the case with journal articles), secured by DOIs. * It is still true that many data providers - individuals or projects - can not find a repository for their (type of) data which would provide a DOI (or other persistent identifier) and that many data centers and databases holding valuable data have a hard time adding DOIs as a feature of their systems for conceptual, legacy or funding reasons. * The typical evolution of many important data collections or data products - such as the Global Carbon Budget - can adequately be tracked with yearly (or less frequent) issues of dataset and data article, each having a new DOI. However, issuing a new DOI for a dataset extended in time clashes with many producers' wish to amass all references to the developing dataset under one citation (and one DOI). * Current practises with DOIs and metadata associated with DOIs need to be clarified and amended so the identifier systems can and do express and track the relationships between versions of data, addressing extensions, corrections, modifications, revisions and retractions in an unambiguous (and machine readable) manner, while also removing extraneous information (dates, page numbers) from the identifier itself. * Similarly, we recognize a clear need to hold one or more copies of important data in different locations (continents), under different governance and technologies but to still be able to identify these copies as intellectually identical. Today, however, we observe identical datasets held in separate repositories with different metadata and DOIs without a process to easily identify the duplicates. * The dataset and data article - coupled with a research article citing both and drawing conclusions and perhaps with an additional article describing and publishing the software - offer a valid and vivid example of linking objects reliably across many players' (publishers') systems. Too often, however, establishing such linkages requires substantial human intervention to initiate and synchronize the necessary processes, in particular to ensure high-fidelity mutual citation among the individual items. As editors of a data journal we firmly embrace the notion of persistence and persistent identifiers, in particular DOIs. We see the need and applaud all efforts to enhance its features to serve the important needs of published and linked data.
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NASA Astrophysics Data System (ADS)
Seneviratne, S. I.; Humphrey, V.; Nicolai-Shaw, N.; Gudmundsson, L.; Guillod, B.; Hirschi, M.; Michel, D.; Orth, R.; Zscheischler, J.
2016-12-01
In recent years, several new satellite products have been derived which allow an unprecendented assessment of terrestrial water storage and land-atmosphere dynamics. This presentation will review some of these new developments, with a focus on drought dynamics, plant-water interactions, and soil moisture-atmosphere feedbacks. Results derived based on the Gravity Recovery and Climate Experiment (GRACE, Humphrey et al. 2016) and the European Space Agency Climate Change Initiative (ESA CCI) Soil Moisture dataset (Nicolai-Shaw et al. 2015, 2016; Hirschi et al. 2014) will be highlighted, as well as assessments using satellite-based estimates of evapotranspiration (Mueller and Seneviratne 2014, Michel et al. 2016), vegetation activity (Zscheischler et al. 2015), and combined soil moisture and precipitation analyses (Guillod et al. 2015). These findings provide new insights on the development of prediction capabilities for droughts, precipitation events, and heat waves, and the reduction of uncertainties in climate model projections. References: Guillod, B.P., B. Orlowsky, D.G. Miralles, A.J. Teuling, and S.I. Seneviratne, 2015. Nature Communications, 6:6443, DOI: 10.1038/ncomms7443 Hirschi, M., B. Mueller, W. Dorigo, and S.I. Seneviratne, 2014. Remote Sensing of Environment, 154, 246-252. Humphrey, V., L. Gudmundsson, and S.I. Seneviratne, 2016. Surv. Geophysics, 37, 357-395, DOI 10.1007/s10712-016-9367-1. Michel, D., et al. 2016. Hydrol. Earth Syst. Sci. 20, 803-822, doi:10.5194/hess-20-803-2016. Mueller, M., and S.I. Seneviratne, 2014. Geophys. Res. Lett., 41, 1-7, doi:10.1002/2013GL058055. Nicolai-Shaw, N., L. Gudmundsson, M. Hirschi, and S.I. Seneviratne, 2016. Geophys. Res. Lett., in review. Nicolai-Shaw, N., M. Hirschi, H. Mittelbach, and S.I. Seneviratne, 2015. Journal of Geophysical Research, 120, doi:10.1002/2015JD023305. Zscheischler, J., R. Orth, and S.I. Seneviratne, 2015. Geophys. Res. Lett., 42, 9816-9824, doi:10.1002/2015GL066563.
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Self Assembly Nonlinear Optical Effects with Novel Small Metal Cluster Systems
2013-07-29
Regents of the University of Michigan 3003 S. State St Ann Arbor, MI 48109 -1274 REPORT DOCUMENTATION PAGE b . ABSTRACT UU c. THIS PAGE UU 2. REPORT TYPE...Journal of Physical Chemistry Letters, (09 2011): 0. doi: 10.1021/jz200738t 10/30/2011 4.00 Travis B . Clark, Meghan E. Orr, Daniel C. Flynn, Theodore...jp2005925 10/30/2011 5.00 Mary Sajini Devadas , Junhyung Kim, Ekkehard Sinn, Dongil Lee, Theodore Goodson, Guda Ramakrishna. Unique Ultrafast Visible
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van Nassau, Femke; Singh, Amika S; van Mechelen, Willem; Brug, Johannes; Chin A Paw, Mai J M
2014-08-01
The school-based Dutch Obesity Intervention in Teenagers (DOiT) program is an evidence-based obesity prevention program. In preparation for dissemination throughout the Netherlands, this study aimed to adapt the initial program and to develop an implementation strategy and materials. We revisited the Intervention Mapping (IM) protocol, using results of the previous process evaluation and additional focus groups and interviews with students, parents, teachers, and professionals. The adapted 2-year DOiT program consists of a classroom, an environmental and a parental component. The year 1 lessons aim to increase awareness and knowledge of healthy behaviors. The lessons in year 2 focus on the influence of the (obesogenic) environment. The stepwise development of the implementation strategy resulted in objectives that support teachers' implementation. We developed a 7-step implementation strategy and supporting materials by translating the objectives into essential elements and practical strategies. This study illustrates how revisiting the IM protocol resulted in an adapted program and tailored implementation strategy based on previous evaluations as well as input from different stakeholders. The stepwise development of DOiT can serve as an example for other evidence-based programs in preparation for wider dissemination. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.
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Glynn, Pierre D.; Voinov, Alexey A.; Shapiro, Carl D.; White, Paul A.
2018-01-01
Our different kinds of minds and types of thinking affect the ways we decide, take action, and cooperate (or not). The comment by Walker et al. (2018, https://doi.org/10.1002/2017EF000750) illustrates several points made by Glynn et al. (2017, https://doi.org/10.1002/2016EF000487) and many other articles. Namely, biases and beliefs often drive scientific reasoning, and scientists, just like other humans, are intimately attached to their values and heuristics. Scientists, just like many other people, also tend to read and interpret text in ways that best match their individual perceptions of a problem or issue: in many cases paraphrasing and changing the meaning of what they read to better match their initial ideas. Walker et al. are doing interesting and important research on uncertainty. Nonetheless, they misinterpret the work, assumptions, and conclusions brought forth by Glynn et al. (2017, https://doi.org/10.1002/2016EF000487).
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Characterizing SHP2 as a Novel Therapeutic Target in Breast Cancer
2012-02-01
50(12), 2339-56. doi:10.1021/bi1014453 Zhang, X., He, Y., Liu, S., Yu, Z., Jiang, Z. X., Yang, Z., Dong, Y., et al. (2010). Salicylic Acid Based...Overall, what we have found so far has been surprising, with the data suggesting that the presence of a -2 acidic residue in the substrate peptide...helped to refine the initial docking poses, with the initial hypothesis being that the pY -1 and -4 position acidic amino acids will bind a pair of
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Compact discs as versatile cost-effective substrates for releasable nanopatterned aluminium films
NASA Astrophysics Data System (ADS)
Barrios, Carlos Angulo; Canalejas-Tejero, Víctor
2015-02-01
We demonstrate that standard polycarbonate compact disk surfaces can provide unique adhesion to Al films that is both strong enough to permit Al film nanopatterning and weak enough to allow easy nanopatterned Al film detachment using Scotch tape. Transferred Al nanohole arrays on Scotch tape exhibit excellent optical and plasmonic performance.We demonstrate that standard polycarbonate compact disk surfaces can provide unique adhesion to Al films that is both strong enough to permit Al film nanopatterning and weak enough to allow easy nanopatterned Al film detachment using Scotch tape. Transferred Al nanohole arrays on Scotch tape exhibit excellent optical and plasmonic performance. Electronic supplementary information (ESI) available: 1. Optical simulations (Fig. SI.1); 2. Optical coupling via an Al NHA on the Scotch tape (Fig. SI.2); 3. Electrostatics-based opto-mechanical cantilever (Fig. SI.3). Video 1. Transfer of the Al film nanostructured with a nanohole array from a polycarbonate CD surface onto a Scotch tape; Video 2. Opto-mechanical electrostatics-based sensor: electrical attraction. Video 3. Opto-mechanical electrostatics-based sensor: electrical repulsion. See DOI: 10.1039/c4nr06271j
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Aitken, Colin Echeverría; Beznosková, Petra; Vlčkova, Vladislava; Chiu, Wen-Ling; Zhou, Fujun; Valášek, Leoš Shivaya; Hinnebusch, Alan G; Lorsch, Jon R
2016-01-01
Eukaryotic translation initiation factor 3 (eIF3) is a central player in recruitment of the pre-initiation complex (PIC) to mRNA. We probed the effects on mRNA recruitment of a library of S. cerevisiae eIF3 functional variants spanning its 5 essential subunits using an in vitro-reconstituted system. Mutations throughout eIF3 disrupt its interaction with the PIC and diminish its ability to accelerate recruitment to a native yeast mRNA. Alterations to the eIF3a CTD and eIF3b/i/g significantly slow mRNA recruitment, and mutations within eIF3b/i/g destabilize eIF2•GTP•Met-tRNAi binding to the PIC. Using model mRNAs lacking contacts with the 40S entry or exit channels, we uncovered a critical role for eIF3 requiring the eIF3a NTD, in stabilizing mRNA interactions at the exit channel, and an ancillary role at the entry channel requiring residues of the eIF3a CTD. These functions are redundant: defects at each channel can be rescued by filling the other channel with mRNA. DOI: http://dx.doi.org/10.7554/eLife.20934.001 PMID:27782884
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Monitoring ATP dynamics in electrically active white matter tracts
Trevisiol, Andrea; Saab, Aiman S; Winkler, Ulrike; Marx, Grit; Imamura, Hiromi; Möbius, Wiebke; Kusch, Kathrin; Nave, Klaus-Armin; Hirrlinger, Johannes
2017-01-01
In several neurodegenerative diseases and myelin disorders, the degeneration profiles of myelinated axons are compatible with underlying energy deficits. However, it is presently impossible to measure selectively axonal ATP levels in the electrically active nervous system. We combined transgenic expression of an ATP-sensor in neurons of mice with confocal FRET imaging and electrophysiological recordings of acutely isolated optic nerves. This allowed us to monitor dynamic changes and activity-dependent axonal ATP homeostasis at the cellular level and in real time. We find that changes in ATP levels correlate well with compound action potentials. However, this correlation is disrupted when metabolism of lactate is inhibited, suggesting that axonal glycolysis products are not sufficient to maintain mitochondrial energy metabolism of electrically active axons. The combined monitoring of cellular ATP and electrical activity is a novel tool to study neuronal and glial energy metabolism in normal physiology and in models of neurodegenerative disorders. DOI: http://dx.doi.org/10.7554/eLife.24241.001 PMID:28414271
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Nanoscale protein architecture of the kidney glomerular basement membrane
Suleiman, Hani; Zhang, Lei; Roth, Robyn; Heuser, John E; Miner, Jeffrey H; Shaw, Andrey S; Dani, Adish
2013-01-01
In multicellular organisms, proteins of the extracellular matrix (ECM) play structural and functional roles in essentially all organs, so understanding ECM protein organization in health and disease remains an important goal. Here, we used sub-diffraction resolution stochastic optical reconstruction microscopy (STORM) to resolve the in situ molecular organization of proteins within the kidney glomerular basement membrane (GBM), an essential mediator of glomerular ultrafiltration. Using multichannel STORM and STORM-electron microscopy correlation, we constructed a molecular reference frame that revealed a laminar organization of ECM proteins within the GBM. Separate analyses of domains near the N- and C-termini of agrin, laminin, and collagen IV in mouse and human GBM revealed a highly oriented macromolecular organization. Our analysis also revealed disruptions in this GBM architecture in a mouse model of Alport syndrome. These results provide the first nanoscopic glimpse into the organization of a complex ECM. DOI: http://dx.doi.org/10.7554/eLife.01149.001 PMID:24137544
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Activity and Ca2+ regulate the mobility of TRPV1 channels in the plasma membrane of sensory neurons
Senning, Eric N; Gordon, Sharona E
2015-01-01
TRPV1 channels are gated by a variety of thermal, chemical, and mechanical stimuli. We used optical recording of Ca2+ influx through TRPV1 to measure activity and mobility of single TRPV1 molecules in isolated dorsal root ganglion neurons and cell lines. The opening of single TRPV1 channels produced sparklets, representing localized regions of elevated Ca2+. Unlike sparklets reported for L-type Ca2+ channels, TRPV4 channels, and AchR channels, TRPV1 channels diffused laterally in the plasma membrane as they gated. Mobility was highly variable from channel-to-channel and, to a smaller extent, from cell to cell. Most surprisingly, we found that mobility decreased upon channel activation by capsaicin, but only in the presence of extracellular Ca2+. We propose that decreased mobility of open TRPV1 could act as a diffusion trap to concentrate channels in cell regions with high activity. DOI: http://dx.doi.org/10.7554/eLife.03819.001 PMID:25569155
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A novel perivascular cell population in the zebrafish brain
Galanternik, Marina Venero; Castranova, Daniel; Gore, Aniket V; Blewett, Nathan H; Jung, Hyun Min; Stratman, Amber N; Kirby, Martha R; Iben, James; Miller, Mayumi F; Kawakami, Koichi; Maraia, Richard J; Weinstein, Brant M
2017-01-01
The blood-brain barrier is essential for the proper homeostasis and function of the CNS, but its mechanism of function is poorly understood. Perivascular cells surrounding brain blood vessels are thought to be important for blood-brain barrier establishment, but their roles are not well defined. Here, we describe a novel perivascular cell population closely associated with blood vessels on the zebrafish brain. Based on similarities in their morphology, location, and scavenger behavior, these cells appear to be the zebrafish equivalent of cells variably characterized as Fluorescent Granular Perithelial cells (FGPs), perivascular macrophages, or ‘Mato Cells’ in mammals. Despite their macrophage-like morphology and perivascular location, zebrafish FGPs appear molecularly most similar to lymphatic endothelium, and our imaging studies suggest that these cells emerge by differentiation from endothelium of the optic choroidal vascular plexus. Our findings provide the first report of a perivascular cell population in the brain derived from vascular endothelium. DOI: http://dx.doi.org/10.7554/eLife.24369.001 PMID:28395729
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Mendes, César S; Bartos, Imre; Akay, Turgay; Márka, Szabolcs; Mann, Richard S
2013-01-01
Coordinated walking in vertebrates and multi-legged invertebrates such as Drosophila melanogaster requires a complex neural network coupled to sensory feedback. An understanding of this network will benefit from systems such as Drosophila that have the ability to genetically manipulate neural activities. However, the fly's small size makes it challenging to analyze walking in this system. In order to overcome this limitation, we developed an optical method coupled with high-speed imaging that allows the tracking and quantification of gait parameters in freely walking flies with high temporal and spatial resolution. Using this method, we present a comprehensive description of many locomotion parameters, such as gait, tarsal positioning, and intersegmental and left-right coordination for wild type fruit flies. Surprisingly, we find that inactivation of sensory neurons in the fly's legs, to block proprioceptive feedback, led to deficient step precision, but interleg coordination and the ability to execute a tripod gait were unaffected. DOI: http://dx.doi.org/10.7554/eLife.00231.001 PMID:23326642
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Wu, Ming; Nern, Aljoscha; Williamson, W Ryan; Morimoto, Mai M; Reiser, Michael B; Card, Gwyneth M; Rubin, Gerald M
2016-01-01
Visual projection neurons (VPNs) provide an anatomical connection between early visual processing and higher brain regions. Here we characterize lobula columnar (LC) cells, a class of Drosophila VPNs that project to distinct central brain structures called optic glomeruli. We anatomically describe 22 different LC types and show that, for several types, optogenetic activation in freely moving flies evokes specific behaviors. The activation phenotypes of two LC types closely resemble natural avoidance behaviors triggered by a visual loom. In vivo two-photon calcium imaging reveals that these LC types respond to looming stimuli, while another type does not, but instead responds to the motion of a small object. Activation of LC neurons on only one side of the brain can result in attractive or aversive turning behaviors depending on the cell type. Our results indicate that LC neurons convey information on the presence and location of visual features relevant for specific behaviors. DOI: http://dx.doi.org/10.7554/eLife.21022.001 PMID:28029094
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Dooley, Katherine L; Arain, Muzammil A; Feldbaum, David; Frolov, Valery V; Heintze, Matthew; Hoak, Daniel; Khazanov, Efim A; Lucianetti, Antonio; Martin, Rodica M; Mueller, Guido; Palashov, Oleg; Quetschke, Volker; Reitze, David H; Savage, R L; Tanner, D B; Williams, Luke F; Wu, Wan
2012-03-01
We present the design and performance of the LIGO Input Optics subsystem as implemented for the sixth science run of the LIGO interferometers. The Initial LIGO Input Optics experienced thermal side effects when operating with 7 W input power. We designed, built, and implemented improved versions of the Input Optics for Enhanced LIGO, an incremental upgrade to the Initial LIGO interferometers, designed to run with 30 W input power. At four times the power of Initial LIGO, the Enhanced LIGO Input Optics demonstrated improved performance including better optical isolation, less thermal drift, minimal thermal lensing, and higher optical efficiency. The success of the Input Optics design fosters confidence for its ability to perform well in Advanced LIGO.
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Federal Register 2010, 2011, 2012, 2013, 2014
2012-02-06
...] Commercial Wind Leasing and Site Assessment Activities on the Atlantic Outer Continental Shelf Offshore... governments, offshore wind energy developers, and the public in the Department of the Interior's (DOI) ``Smart from the Start'' wind energy initiative offshore Massachusetts. The purpose of the ``Smart from the...
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Erratum: Correction to: Water in the Earth's Interior: Distribution and Origin
NASA Astrophysics Data System (ADS)
Peslier, Anne H.; Schönbächler, Maria; Busemann, Henner; Karato, Shun-Ichiro
2017-10-01
Correction to: Space Sci Rev DOI: 10.1007/s11214-017-0387-z This article has been corrected. Figure 3 was initially published with erroneous axis titles in Fig. 3B and 3D where the x axis should be Cpx H2O, instead of Grt H2O.
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Kulkarni, Abhishek; Ertekin, Deniz; Lee, Chi-Hon; Hummel, Thomas
2016-01-01
The precise recognition of appropriate synaptic partner neurons is a critical step during neural circuit assembly. However, little is known about the developmental context in which recognition specificity is important to establish synaptic contacts. We show that in the Drosophila visual system, sequential segregation of photoreceptor afferents, reflecting their birth order, lead to differential positioning of their growth cones in the early target region. By combining loss- and gain-of-function analyses we demonstrate that relative differences in the expression of the transcription factor Sequoia regulate R cell growth cone segregation. This initial growth cone positioning is consolidated via cell-adhesion molecule Capricious in R8 axons. Further, we show that the initial growth cone positioning determines synaptic layer selection through proximity-based axon-target interactions. Taken together, we demonstrate that birth order dependent pre-patterning of afferent growth cones is an essential pre-requisite for the identification of synaptic partner neurons during visual map formation in Drosophila. DOI: http://dx.doi.org/10.7554/eLife.13715.001 PMID:26987017
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The structure of SV40 large T hexameric helicase in complex with AT-rich origin DNA
Gai, Dahai; Wang, Damian; Li, Shu-Xing; Chen, Xiaojiang S
2016-01-01
DNA replication is a fundamental biological process. The initial step in eukaryotic DNA replication is the assembly of the pre-initiation complex, including the formation of two head-to-head hexameric helicases around the replication origin. How these hexameric helicases interact with their origin dsDNA remains unknown. Here, we report the co-crystal structure of the SV40 Large-T Antigen (LT) hexameric helicase bound to its origin dsDNA. The structure shows that the six subunits form a near-planar ring that interacts with the origin, so that each subunit makes unique contacts with the DNA. The origin dsDNA inside the narrower AAA+ domain channel shows partial melting due to the compression of the two phosphate backbones, forcing Watson-Crick base-pairs within the duplex to flip outward. This structure provides the first snapshot of a hexameric helicase binding to origin dsDNA, and suggests a possible mechanism of origin melting by LT during SV40 replication in eukaryotic cells. DOI: http://dx.doi.org/10.7554/eLife.18129.001 PMID:27921994
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Spontaneous symbiotic reprogramming of plant roots triggered by receptor-like kinases
Ried, Martina Katharina; Antolín-Llovera, Meritxell; Parniske, Martin
2014-01-01
Symbiosis Receptor-like Kinase (SYMRK) is indispensable for the development of phosphate-acquiring arbuscular mycorrhiza (AM) as well as nitrogen-fixing root nodule symbiosis, but the mechanisms that discriminate between the two distinct symbiotic developmental fates have been enigmatic. In this study, we show that upon ectopic expression, the receptor-like kinase genes Nod Factor Receptor 1 (NFR1), NFR5, and SYMRK initiate spontaneous nodule organogenesis and nodulation-related gene expression in the absence of rhizobia. Furthermore, overexpressed NFR1 or NFR5 associated with endogenous SYMRK in roots of the legume Lotus japonicus. Epistasis tests revealed that the dominant active SYMRK allele initiates signalling independently of either the NFR1 or NFR5 gene and upstream of a set of genes required for the generation or decoding of calcium-spiking in both symbioses. Only SYMRK but not NFR overexpression triggered the expression of AM-related genes, indicating that the receptors play a key role in the decision between AM- or root nodule symbiosis-development. DOI: http://dx.doi.org/10.7554/eLife.03891.001 PMID:25422918
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A history of herpetologists and herpetology in the U.S. Department of the Interior
Lovich, Jeffrey E.; Scott, Norman J.; Bury, R. Bruce; Dodd, C. Kenneth; McDiarmid, Roy W.
2012-01-01
The U.S. Department of the Interior (DOI) has a long and distinguished history of employing herpetologists to conduct basic and applied research to better manage amphibian and reptile populations on public lands and even outside the boundaries of the United States. This history extends back over 125 years with roots in the U.S. Biological Survey, the Fish and Wildlife Service, the Bureau of Land Management, the National Park Service and later, the National Biological Service. In more recent times, the DOI employed more professional herpetologists than any single organization in the world, especially in the U.S. Geological Survey. In 1938, Henry Fitch was the first Interior scientist hired who conducted substantial herpetological research. William and Lucille Stickel of the Fish and Wildlife Service conducted herpetological research throughout the period from the 1940s-1980s but most DOI herpetologists were hired from 1975-80 with another hiring spike from 2000-2005. The former spike was congruent with early versions of the Endangered Species Act while the latter reflected growing recognition of global amphibian decline and the creation of the Amphibian Research and Monitoring Initiative in DOI. Collectively, these herpetologists produced hundreds of books, scientific publications and other scholarly publications, many of which are classics in the literature. In addition, many have served as officers and on the boards of numerous scientific societies particularly those specializing in amphibian and reptile research. The DOI shows a continuing commitment to funding herpetological research by hiring young scientists to replace the aging ranks of herpetologists who started their careers in the 1970s. This commitment is critical given the global decline of both amphibians and reptiles, including those found on public lands in the United States.
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A Compilation of Global Bio-Optical in Situ Data for Ocean-Colour Satellite Applications
NASA Technical Reports Server (NTRS)
Valente, Andre; Sathyendranath, Shubha; Brotus, Vanda; Groom, Steve; Grant, Michael; Taberner, Malcolm; Antoine, David; Arnone, Robert; Balch, William M.; Barker, Kathryn;
2016-01-01
A compiled set of in situ data is important to evaluate the quality of ocean-colour satellite-data records. Here we describe the data compiled for the validation of the ocean-colour products from the ESA Ocean Colour Climate Change Initiative (OC-CCI). The data were acquired from several sources (MOBY, BOUSSOLE, AERONET-OC, SeaBASS, NOMAD, MERMAID, AMT, ICES, HOT, GePCO), span between 1997 and 2012, and have a global distribution. Observations of the following variables were compiled: spectral remote-sensing reflectances, concentrations of chlorophyll a, spectral inherent optical properties and spectral diffuse attenuation coefficients. The data were from multi-project archives acquired via the open internet services or from individual projects, acquired directly from data providers. Methodologies were implemented for homogenisation, quality control and merging of all data. No changes were made to the original data, other than averaging of observations that were close in time and space, elimination of some points after quality control and conversion to a standard format. The final result is a merged table designed for validation of satellite-derived ocean-colour products and available in text format. Metadata of each in situ measurement (original source, cruise or experiment, principal investigator) were preserved throughout the work and made available in the final table. Using all the data in a validation exercise increases the number of matchups and enhances the representativeness of different marine regimes. By making available the metadata, it is also possible to analyse each set of data separately. The compiled data are available at doi:10.1594PANGAEA.854832 (Valente et al., 2015).
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Fast Positive Breakdown, NBEs, and Lightning Initiation
NASA Astrophysics Data System (ADS)
Krehbiel, P. R.; Rison, W.; Stock, M.; Edens, H. E.; Shao, X. M.; Thomas, R. J.; Stanley, M. A.; Zhang, Y.
2016-12-01
High power narrrow bipolar events (NBEs) have been found to be produced by arelatively unknown type of discharge, called fast positive breakdown (Rison etal., 2016). The breakdown occurs with a wide range of strengths, both in terms of its broadband sferic and its VHF radiation, and is found to be theinitiating event of many and likely all lightning discharges inside storms. Itdoes not produce a conducting channel but instead appears to be produced by avolumetric system of repeated, cascading positive streamers in virgin air.That positive corona and streamers would be responsible for initiatinglightning was proposed in the 1960s by Loeb, Dawson and Winn. In the 1970sPhelps and Griffiths showed that the streamers would be self-intensifying,leading to negative breakdown being initiated back at their starting points.Petersen et al. (2008) described experimental results showing that thestreamers could be initiated by ice crystals at cold temperatures, and thephysical processes leading to the breakdown being fast has been reported inrecent modeling studies by Shi et al. (2016). In this paper we summarize the observational data in support of the abovefindings, and report on additional observations of NBEs and lightninginitiation currently being obtained at Kennedy Space Center, Florida. References: Rison W., P.R. Krehbiel M.G.Stock, H.E. Edens, X-M. Shao, R.J. Thomas,M.A. Stanley, Y. Zhang, Observations of narrow bipolar events revealhow lightning is initiated in thunderstorms, Nature Comms. 7, 2016.doi:10.1038/ncomms10721. Petersen, D., Bailey, M., Beasley, W. & Hallett, J. A brief review ofthe problem of lightning initiation and a hypothesis of initiallightning leader formation. J. Geophys. Res. 113, D17205 (2008). Shi, F., N. Liu, and H. K. Rassoul (2016), Properties of relativelylong streamers initiated from an isolated hydrometeor, J. Geophys.Res. Atmos., 121, 7284-7295, doi:10.1002/2015JD024580.
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Direct writing of metal nanostructures: lithographic tools for nanoplasmonics research.
Leggett, Graham J
2011-03-22
Continued progress in the fast-growing field of nanoplasmonics will require the development of new methods for the fabrication of metal nanostructures. Optical lithography provides a continually expanding tool box. Two-photon processes, as demonstrated by Shukla et al. (doi: 10.1021/nn103015g), enable the fabrication of gold nanostructures encapsulated in dielectric material in a simple, direct process and offer the prospect of three-dimensional fabrication. At higher resolution, scanning probe techniques enable nanoparticle particle placement by localized oxidation, and near-field sintering of nanoparticulate films enables direct writing of nanowires. Direct laser "printing" of single gold nanoparticles offers a remarkable capability for the controlled fabrication of model structures for fundamental studies, particle-by-particle. Optical methods continue to provide a powerful support for research into metamaterials.
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NASA Astrophysics Data System (ADS)
Alam, Rabeka; Zylstra, Joshua; Fontaine, Danielle M.; Branchini, Bruce R.; Maye, Mathew M.
2013-05-01
Sequential bioluminescence resonance energy transfer (BRET) and fluorescence resonance energy transfer (FRET) from firefly luciferase to red fluorescent proteins using quantum dot or rod acceptor/donor linkers is described. The effect of morphology and tuned optical properties on the efficiency of this unique BRET-FRET system was evaluated.Sequential bioluminescence resonance energy transfer (BRET) and fluorescence resonance energy transfer (FRET) from firefly luciferase to red fluorescent proteins using quantum dot or rod acceptor/donor linkers is described. The effect of morphology and tuned optical properties on the efficiency of this unique BRET-FRET system was evaluated. Electronic supplementary information (ESI) available: Experimental details, Fig. S1 and Table S1-S4. See DOI: 10.1039/c3nr01842c
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43 CFR Appendix B to Part 2 - Internet Addresses
Code of Federal Regulations, 2010 CFR
2010-10-01
... Page: http://www.doi.gov 2. DOI FOIA Home Page: http://www.doi.gov/foia/ 3. DOI Reference Guide for Obtaining Information: http://www.doi.gov/foia/foitabl.htm 4. List of DOI Public Affairs Offices: http://www.doi.gov/foia/list.html 5. DOI FOIA Contacts: http://www.doi.gov/foia/contacts.html 6. DOI FOIA...
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43 CFR Appendix B to Part 2 - Internet Addresses
Code of Federal Regulations, 2012 CFR
2012-10-01
... Page: http://www.doi.gov 2. DOI FOIA Home Page: http://www.doi.gov/foia/ 3. DOI Reference Guide for Obtaining Information: http://www.doi.gov/foia/foitabl.htm 4. List of DOI Public Affairs Offices: http://www.doi.gov/foia/list.html 5. DOI FOIA Contacts: http://www.doi.gov/foia/contacts.html 6. DOI FOIA...
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Conceptual Design for the Amphibian Research and Monitoring Initiative (ARMI)
NASA Astrophysics Data System (ADS)
Battaglin, W. A.; Langtimm, C. A.; Adams, M. J.; Gallant, A. L.; James, D. L.
2001-12-01
In 2000, the President of the United States (US) and Congress directed Department of Interior (DOI) agencies to develop a program for monitoring trends in amphibian populations on DOI lands and to conduct research into causes of declines. The U.S. Geological Survey (USGS) was given lead responsibility for planning and implementing the Amphibian Research and Monitoring Initiative (ARMI) in cooperation with the National Park Service (NPS), Fish and Wildlife Service, and Bureau of Land Management. The program objectives are to (1) establish a network for monitoring the status and distribution of amphibian species on DOI lands; (2) identify and monitor environmental conditions known to affect amphibian populations; (3) conduct research on causes of amphibian population change and malformations; and (4) provide information to resource managers, policy makers, and the public in support of amphibian conservation. The ARMI program will integrate research efforts of USGS, other Federal, and non-federal herpetologists, hydrologists, and geographers across the Nation. ARMI will conduct a small number (~20) of intensive research efforts (for example, studies linking amphibian population changes to hydrologic conditions) and a larger number (~50) of more generalized inventory and monitoring studies encompassing broader areas such as NPS units. ARMI will coordinate with and try to augment other amphibian inventory studies such as the National Amphibian Atlas and the North American Amphibian Monitoring Program. ARMI will develop and test protocols for the standardized collection of amphibian data and provide a centrally managed database designed to simplify data entry, retrieval, and analysis. ARMI pilot projects are underway at locations across the US.
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Structural characterization of ribosome recruitment and translocation by type IV IRES
Murray, Jason; Savva, Christos G; Shin, Byung-Sik; Dever, Thomas E; Ramakrishnan, V; Fernández, Israel S
2016-01-01
Viral mRNA sequences with a type IV IRES are able to initiate translation without any host initiation factors. Initial recruitment of the small ribosomal subunit as well as two translocation steps before the first peptidyl transfer are essential for the initiation of translation by these mRNAs. Using electron cryomicroscopy (cryo-EM) we have structurally characterized at high resolution how the Cricket Paralysis Virus Internal Ribosomal Entry Site (CrPV-IRES) binds the small ribosomal subunit (40S) and the translocation intermediate stabilized by elongation factor 2 (eEF2). The CrPV-IRES restricts the otherwise flexible 40S head to a conformation compatible with binding the large ribosomal subunit (60S). Once the 60S is recruited, the binary CrPV-IRES/80S complex oscillates between canonical and rotated states (Fernández et al., 2014; Koh et al., 2014), as seen for pre-translocation complexes with tRNAs. Elongation factor eEF2 with a GTP analog stabilizes the ribosome-IRES complex in a rotated state with an extra ~3 degrees of rotation. Key residues in domain IV of eEF2 interact with pseudoknot I (PKI) of the CrPV-IRES stabilizing it in a conformation reminiscent of a hybrid tRNA state. The structure explains how diphthamide, a eukaryotic and archaeal specific post-translational modification of a histidine residue of eEF2, is involved in translocation. DOI: http://dx.doi.org/10.7554/eLife.13567.001 PMID:27159451
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Erickson, Kenneth L.
2001-01-01
A thin-film optical initiator having an inert, transparent substrate, a reactive thin film, which can be either an explosive or a pyrotechnic, and a reflective thin film. The resultant thin-film optical initiator system also comprises a fiber-optic cable connected to a low-energy laser source, an output charge, and an initiator housing. The reactive thin film, which may contain very thin embedded layers or be a co-deposit of a light-absorbing material such as carbon, absorbs the incident laser light, is volumetrically heated, and explodes against the output charge, imparting about 5 to 20 times more energy than in the incident laser pulse.
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NASA Astrophysics Data System (ADS)
Chen, Jingwen; Sun, Yingqi; Chen, Qian; Wang, Le; Wang, Suhe; Tang, Yun; Shi, Xiangyang; Wang, Han
2016-07-01
Multifunctional gold nanocomposites, which were designed as dendrimer-entrapped gold nanoparticles functionalized with gadolinium, cyanine dye (Cy5.5), and folic acid, were synthesized to be used as the first dendrimer-based clinical nanoprobes for targeted X-ray computed tomography/magnetic resonance/optical trimodal imaging in vitro and in vivo of human non-small cell cancer cells.Multifunctional gold nanocomposites, which were designed as dendrimer-entrapped gold nanoparticles functionalized with gadolinium, cyanine dye (Cy5.5), and folic acid, were synthesized to be used as the first dendrimer-based clinical nanoprobes for targeted X-ray computed tomography/magnetic resonance/optical trimodal imaging in vitro and in vivo of human non-small cell cancer cells. Electronic supplementary information (ESI) available: Synthesis and characterization data of the nanoprobes; biocompatibility results; confirmation of the tumor cell uptake of the nanoprobes in vitro and in vivo; biodistribution results in vivo. See DOI: 10.1039/c6nr03143a
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NASA Astrophysics Data System (ADS)
Dewey, M. C.; Goldblatt, C.
2017-12-01
Energy balance requires that energy absorbed and emitted at the top of the atmosphere equal; this is maintained via the Planck feedback whereby outgoing longwave radiation (OLR) increases as surface temperature increases. There are two cases where this breaks down: the runaway greenhouse (known from planetary sciences theory) characterized by an asymptotic limit on OLR from moist atmospheres, and the super-greenhouse (known from tropical meteorology observations) where OLR decreases with surface temperature when the atmosphere is moist aloft. Here we show that the runaway greenhouse limit can be empirically observed and constrained in Earth's tropics, that the runaway and super-greenhouse occur as part of the same physical phenomenon, and that the transition through the super-greenhouse to a local runaway greenhouse is intimately linked to the onset of deep convection. A runaway greenhouse occurs when water vapour causes the troposphere to become optically thick to thermal radiation from the surface and a limit on OLR emerges as thermal emission is from a constant temperature level aloft. This limit is modelled as 282 W/m/m [Goldblatt et al, 2013]. Using satellite data from Earth's tropics, we find an empirical value of this limit of 280 W/m/m, in excellent agreement with the model.A column transitioning to a runaway greenhouse typically overshoots the runaway limit and then OLR decreases with increasing surface temperature until the runaway limit is reached after which OLR remains constant. The term super-greenhouse effect (SGE) has been used to describe OLR decreasing with surface warming, observed in these satellite measurements. We show the SGE is one and the same as the transition to a local runaway greenhouse, and represents a fundamental shift in the radiation response of the earth system, rather than simply an extension of water vapour feedback. This transition via SGE from an optically thin to optically thick troposphere is facilitated by enhanced moistening of the upper troposphere through active convection. That convection itself may be initiated by the changes to the atmospheric optical depth and consequent need for adjustment of the surface energy budget.Refs: Goldblatt et al., 2013, Nature Geoscience, 6, 661-667, doi:10.1038/NGEO1892.
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An allosteric transport mechanism for the AcrAB-TolC multidrug efflux pump
Wang, Zhao; Fan, Guizhen; Hryc, Corey F; Blaza, James N; Serysheva, Irina I; Schmid, Michael F; Chiu, Wah; Luisi, Ben F; Du, Dijun
2017-01-01
Bacterial efflux pumps confer multidrug resistance by transporting diverse antibiotics from the cell. In Gram-negative bacteria, some of these pumps form multi-protein assemblies that span the cell envelope. Here, we report the near-atomic resolution cryoEM structures of the Escherichia coli AcrAB-TolC multidrug efflux pump in resting and drug transport states, revealing a quaternary structural switch that allosterically couples and synchronizes initial ligand binding with channel opening. Within the transport-activated state, the channel remains open even though the pump cycles through three distinct conformations. Collectively, our data provide a dynamic mechanism for the assembly and operation of the AcrAB-TolC pump. DOI: http://dx.doi.org/10.7554/eLife.24905.001 PMID:28355133
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WITHDRAWN: A Descriptive Review Article for Pump Initiation in a Pediatric Diabetes Centre.
Roode, Angela; Smith, Monica
2013-06-27
The Publisher regrets that this article is an accidental duplication of an article that has already been published, DOI of original article:10.1016/j.pedn.2013.01.005. The duplicate article has therefore been withdrawn. Copyright © 2014 Elsevier Inc. All rights reserved. Published by Elsevier Inc. All rights reserved.
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Psychophysiology of Delayed Extinction and Reconsolidation in Humans
2015-04-01
2013). Reconsolidation in a human fear conditioning study: a test of extinction as updating mechanism. Biological Psychology , 92(1), 43–50. doi...strengths of various pharmacological and behavioral, reconsolidation-blocking interventions could be tested . We completed testing for two...conductance, when assessing renewal and reinstatement. Mifepristone was tested as a second pharmacological intervention. After adjusting for initial
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Federal Register 2010, 2011, 2012, 2013, 2014
2011-08-18
... Environmental Assessment. SUMMARY: This notice is being published as an initial step for the purpose of... areas, in accordance with the DOI and the Council on Environmental Quality (CEQ) regulations implementing the provisions of the National Environmental Policy Act (NEPA) of 1969 as amended (42 U.S.C. 4321...
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NASA Astrophysics Data System (ADS)
Taylor, S. M.; Worman, S. L.; Bennett, R.; Bassow, A.
2017-12-01
The Department of the Interior (DOI) partnered with the National Fish and Wildlife Foundation (NFWF) to administer an external funding competition to support coastal resilience projects in the region affected by Hurricane Sandy. The projects complement the DOI Bureau-led projects, but are led by state and local governments, universities, non-profits, community groups, tribes, and other non-Federal entities. In total, the Hurricane Sandy Resilience Program invested over $750 million in approximately 180 projects to repair damage and improve the resilience of habitats, communities and infrastructure to future storms and sea level rise. Project activities include waterway connection and opening, living shoreline, marsh restoration, community resilience planning, data/mapping/modeling, and beach and dune restoration. DOI and NFWF initiated a resilience assessment in 2015 to evaluate the impact of this investment. The assessment began by clarifying the program's resilience goals and the development of ecological and socio-economic metrics across the project activities. Using these metrics, the evaluation is assessing the ecological and community outcomes, cost effectiveness of activities, improved scientific understanding, and temporal and spatial scaling of benefits across resilience activities. Recognizing the unique opportunity afforded by the scale and distribution of projects, NFWF and DOI have invested in monitoring through 2024 to better understand how these projects perform over time. This presentation will describe the evaluation questions, approach, long-term monitoring, online metrics portal, and findings to date.
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Reduction of damage initiation density in fused silica optics via UV laser conditioning
Peterson, John E.; Maricle, Stephen M.; Brusasco, Raymond M.; Penetrante, Bernardino M.
2004-03-16
The present invention provides a method for reducing the density of sites on the surface of fused silica optics that are prone to the initiation of laser-induced damage, resulting in optics which have far fewer catastrophic defects and are better capable of resisting optical deterioration upon exposure for a long period of time to a high-power laser beam having a wavelength of about 360 nm or less. The initiation of laser-induced damage is reduced by conditioning the optic at low fluences below levels that normally lead to catastrophic growth of damage. When the optic is then irradiated at its high fluence design limit, the concentration of catastrophic damage sites that form on the surface of the optic is greatly reduced.
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Correction to: Cyberpsychol Behav Soc Netw 2015;18(2);59-71 DOI: 10.1089/cyber.2014.0343.
2015-11-01
In the February 2015 issue of Cyberpsychology, Behavior, and Social Networking (vol. 18, no. 2, pp. 59–71), the article "Association Between Pornography Use and Sexual Risk Behaviors in Adult Consumers: A Systematic Review," by Emily L. Harkness et al., the second author's name was displayed as "Barbara M. Mullan;" however, the middle initial is incorrect. The authors wish to apologize for the error and Dr. Mullan would like to be cited without a middle initial simply as "B Mullan."
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McDougall, Craig; MacDonald, Michael Peter; Ritsch-Marte, Monika
2016-01-01
Many applications in the life-sciences demand non-contact manipulation tools for forceful but nevertheless delicate handling of various types of sample. Moreover, the system should support high-resolution optical imaging. Here we present a hybrid acoustic/optical manipulation system which utilizes a transparent transducer, making it compatible with high-NA imaging in a microfluidic environment. The powerful acoustic trapping within a layered resonator, which is suitable for highly parallel particle handling, is complemented by the flexibility and selectivity of holographic optical tweezers, with the specimens being under high quality optical monitoring at all times. The dual acoustic/optical nature of the system lends itself to optically measure the exact acoustic force map, by means of direct force measurements on an optically trapped particle. For applications with (ultra-)high demand on the precision of the force measurements, the position of the objective used for the high-NA imaging may have significant influence on the acoustic force map in the probe chamber. We have characterized this influence experimentally and the findings were confirmed by model simulations. We show that it is possible to design the chamber and to choose the operating point in such a way as to avoid perturbations due to the objective lens. Moreover, we found that measuring the electrical impedance of the transducer provides an easy indicator for the acoustic resonances. PMID:27025398
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Novel Combinatory Approaches to Repair Visual System after Optic Nerve Damage
2013-09-01
5a. CONTRACT NUMBER W81XWH-12-1-0319 5b. GRANT NUMBER W81XWH-12-1-0319 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Kevin K. Park, PhD (PI...online at http:// dx.doi.org/10.1016/j.expneurol.2013.03.001. Acknowledgments This work was supported by grants from U.S. Army W81XWH-05- 1-0061 (VPL, PT...cycle, and survival ( Cardone et al., 1998; Diehl, Cheng, Roussel, & Sherr, 1998; Hers, Vincent, & Tavare, 2011; Okumura et al., 2002; Sarbassov
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2015-06-17
Example 2: OpCast_cron.sh #!/bin/sh # # # # # Cron helper script This script may be called with the appropriate arguments to reproduce what the...testing. Example 3: OpCast.sh #!/bin/sh # # helper script to set up environment for call to make_merged_product.sh # # This script can be called stand...ecosystem model skill assessment, Journal of Marine Systems, 76(1-2), 64-82, doi:10.1016/j.jmarsys.2008.05.014. Jolliff, J. K., S. Ladner, R. Crout, P
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NASA Astrophysics Data System (ADS)
Shi, Wei; Liu, Xinyu; Wei, Chao; Xu, Zhichuan J.; Sim, Stanley Siong Wei; Liu, Linbo; Xu, Chenjie
2015-10-01
Heterogeneous Au-Fe3O4 dumbbell nanoparticles (NPs) are composed of Au NPs and Fe3O4 NPs that bring in optical and magnetic properties respectively. This article reports the engineering of Au-Fe3O4 NPs as gene carriers for magnetic gene transfection as well as contrast agents for micro-optical coherence tomography (μOCT). As a proof-of-concept, Au-Fe3O4 NPs are used to deliver the green fluorescent protein to HEK 293T cells and their entrance into the cells is monitored through μOCT.Heterogeneous Au-Fe3O4 dumbbell nanoparticles (NPs) are composed of Au NPs and Fe3O4 NPs that bring in optical and magnetic properties respectively. This article reports the engineering of Au-Fe3O4 NPs as gene carriers for magnetic gene transfection as well as contrast agents for micro-optical coherence tomography (μOCT). As a proof-of-concept, Au-Fe3O4 NPs are used to deliver the green fluorescent protein to HEK 293T cells and their entrance into the cells is monitored through μOCT. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr05459a
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Ontogeny of the sheathing leaf base in maize (Zea mays).
Johnston, Robyn; Leiboff, Samuel; Scanlon, Michael J
2015-01-01
Leaves develop from the shoot apical meristem (SAM) via recruitment of leaf founder cells. Unlike eudicots, most monocot leaves display parallel venation and sheathing bases wherein the margins overlap the stem. Here we utilized computed tomography (CT) imaging, localization of PIN-FORMED1 (PIN1) auxin transport proteins, and in situ hybridization of leaf developmental transcripts to analyze the ontogeny of monocot leaf morphology in maize (Zea mays). CT imaging of whole-mounted shoot apices illustrates the plastochron-specific stages during initiation of the basal sheath margins from the tubular disc of insertion (DOI). PIN1 localizations identify basipetal auxin transport in the SAM L1 layer at the site of leaf initiation, a process that continues reiteratively during later recruitment of lateral leaf domains. Refinement of these auxin transport domains results in multiple, parallel provascular strands within the initiating primordium. By contrast, auxin is transported from the L2 toward the L1 at the developing margins of the leaf sheath. Transcripts involved in organ boundary formation and dorsiventral patterning accumulate within the DOI, preceding the outgrowth of the overlapping margins of the sheathing leaf base. We suggest a model wherein sheathing bases and parallel veins are both patterned via the extended recruitment of lateral maize leaf domains from the SAM. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.
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NASA Astrophysics Data System (ADS)
Kim, Jin; Song, Sung Ho; Jin, Yoonhee; Park, Hyun-Ji; Yoon, Hyewon; Jeon, Seokwoo; Cho, Seung-Woo
2016-04-01
The applicability of graphene quantum dots (GQDs) for the in vitro and in vivo live imaging and tracking of different types of human stem cells is investigated. GQDs synthesized by the modified graphite intercalated compound method show efficient cellular uptake with improved biocompatibility and highly sensitive optical properties, indicating their feasibility as a bio-imaging probe for stem cell therapy.The applicability of graphene quantum dots (GQDs) for the in vitro and in vivo live imaging and tracking of different types of human stem cells is investigated. GQDs synthesized by the modified graphite intercalated compound method show efficient cellular uptake with improved biocompatibility and highly sensitive optical properties, indicating their feasibility as a bio-imaging probe for stem cell therapy. Electronic supplementary information (ESI) available: Additional results. See DOI: 10.1039/c6nr02143c
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Cannabinoids: clearing the smoke on pain, inflammation and neurodegeneration.
Downer, E J; Finn, D P
2014-03-01
This article is part of a themed section on Cannabinoids 2013. To view the other articles in this section, see Fagan and Campbell (2014) DOI: 10.1111/bph.12492, Ignatowska-Jankowska et al. (2014) DOI: 10.1111/bph.12298, Ligresti et al. (2014) DOI: 10.1111/bph.12410, Lopez-Rodriguez et al. (2014) DOI: 10.1111/bph.12519, Murataeva et al. (2014) DOI: 10.1111/bph.12411, Okine et al. (2014) DOI: 10.1111/bph.12540, Rodríguez-Cueto et al. (2014) DOI: 10.1111/bph.12283, Stanley and O'Sullivan (2014) DOI: 10.1111/bph.12560, Toguri et al. (2014) DOI: 10.1111/bph.12545, Wu et al. (2014) DOI: 10.1111/bph.12500. Linked articles are: Avraham et al. (2014) DOI: 10.1111/bph.12478, Machado et al. (2014) DOI: 10.1111/bph.12488, Ward et al. (2014) DOI: 10.1111/bph.12439. © 2014 The British Pharmacological Society.
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Test of Monin-Obukhov similarity theory using distributed temperature sensing
NASA Astrophysics Data System (ADS)
Cheng, Y.; Sayde, C.; Li, Q.; Gentine, P.
2017-12-01
Monin-Obukhov similarity theory [Monin and Obukhov, 1954] (MOST) has been widely used to calculate atmospheric surface fluxes applying the structure correction functions [Stull, 1988]. The exact forms of the structure correction functions for momentum and heat, which depend on the vertical gradient velocity and temperature, have been determined empirically mostly from the Kansas experiment [Kaimal et al., 1972]. However, due to the limitation of point measurement, the vertical gradient of temperature and horizontal wind speed are not well captured. Here we propose a way to measure the vertical gradient of temperature and horizontal wind speed with high resolution in space (every 12.7 cm) and time (every second) using the Distributed Temperature Sensing [Selker et al., 2006] (DTS), thus determining the exact form of the structure correction functions of MOST under various stability conditions. Two parallel vertical fiber optics will be placed on a tower at the central facility of ARM SGP site. Vertical air temperature will be measured every 12.7 cm by the fiber optics and horizontal wind speed along fiber will be measured. Then vertical gradient of temperature and horizontal wind speed will be calculated and stability correction functions for momentum and heat will be determined. ReferencesKaimal, J. C., Wyngaard, J. C., Izumi, Y., and Cote, O. R. (1972), Spectral characteristics of surface-layer turbulence, Quarterly Journal of the Royal Meteorological Society, 98(417), 563-589, doi: 10.1002/qj.49709841707. Monin, A., and Obukhov, A. (1954), Basic laws of turbulent mixing in the surface layer of the atmosphere, Contrib. Geophys. Inst. Acad. Sci. USSR, 24(151), 163-187. Selker, J., Thévenaz, L., Huwald, H., Mallet, A., Luxemburg, W., van de Giesen, N., Stejskal, M., Zeman, J., Westhoff, M., and Parlange, M. B. (2006), Distributed fiber-optic temperature sensing for hydrologic systems, Water Resources Research, 42, W12202, doi: 10.1029/2006wr005326. Stull, R. (1988), An Introduction to Boundary Layer Meteorology, pp. 666, Kluwer Academic Publishers, Dordrecht.
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Ferradal, Silvina L; Eggebrecht, Adam T; Hassanpour, Mahlega; Snyder, Abraham Z; Culver, Joseph P
2014-01-15
Diffuse optical imaging (DOI) is increasingly becoming a valuable neuroimaging tool when fMRI is precluded. Recent developments in high-density diffuse optical tomography (HD-DOT) overcome previous limitations of sparse DOI systems, providing improved image quality and brain specificity. These improvements in instrumentation prompt the need for advancements in both i) realistic forward light modeling for accurate HD-DOT image reconstruction, and ii) spatial normalization for voxel-wise comparisons across subjects. Individualized forward light models derived from subject-specific anatomical images provide the optimal inverse solutions, but such modeling may not be feasible in all situations. In the absence of subject-specific anatomical images, atlas-based head models registered to the subject's head using cranial fiducials provide an alternative solution. In addition, a standard atlas is attractive because it defines a common coordinate space in which to compare results across subjects. The question therefore arises as to whether atlas-based forward light modeling ensures adequate HD-DOT image quality at the individual and group level. Herein, we demonstrate the feasibility of using atlas-based forward light modeling and spatial normalization methods. Both techniques are validated using subject-matched HD-DOT and fMRI data sets for visual evoked responses measured in five healthy adult subjects. HD-DOT reconstructions obtained with the registered atlas anatomy (i.e. atlas DOT) had an average localization error of 2.7mm relative to reconstructions obtained with the subject-specific anatomical images (i.e. subject-MRI DOT), and 6.6mm relative to fMRI data. At the group level, the localization error of atlas DOT reconstruction was 4.2mm relative to subject-MRI DOT reconstruction, and 6.1mm relative to fMRI. These results show that atlas-based image reconstruction provides a viable approach to individual head modeling for HD-DOT when anatomical imaging is not available. Copyright © 2013. Published by Elsevier Inc.
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NASA Astrophysics Data System (ADS)
Xu, Ronald; Qiang, Bo; Liu, Jun
2005-04-01
Recent advances in diffuse optical imaging and spectroscopy (DOIS) allow the noninvasive measurement of local changes in cerebral oxygenation and hemodynamics. Available DOIS devices fall into three categories: time domain (TD), frequency domain (FD) and continuous wave (CW). The TD and FD devices have potential for high spatial resolution, high temporal resolution and high accuracy measurement, but the instrument cost and the hardware size prevent their wide clinical application. Furthermore, the presence of the low scattering cerebrospinal fluid layer (CSF) and its thickness variation during motion challenges quantitative, continuous monitoring of the cortex layer oxygenation and blood content. MRI has been used to provide a priori knowledge of the head anatomy that helps the NIR image reconstruction. However, the technology is expensive and lacks portability. This paper proposes a method that combines the accuracy of a TD/FD system and the portability of a CW device. With the optical baseline measured by a TD or FD device and the layer thickness characterized by an ultrasound transducer, a conventional CW system may be able to quantify the cortex layer optical absorption with high accuracy. In this paper, the feasibility of using ultrasound guided CW spectroscopy to monitor brain activities was studied on a multi layer head model using Monte Carlo simulation and order of magnitude analysis. A forward algorithm based on diffuse approximation and 2D Fourier Transform was used to optimize the source detector separation. Both analytical and neuron network approaches were developed for inverse calculation of the cortex layer absorption in real time. An ultrasound transducer was used to monitor the thickness of different layers surrounding the cerebral cortex. The concept of ultrasound guided CW spectroscopy was demonstrated by numerical simulation on a 2 layer head model and the use of the ultrasound transducer for layer thickness characterization was verified by animal and bench top results.
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Simulation study of light transport in laser-processed LYSO:Ce detectors with single-side readout
NASA Astrophysics Data System (ADS)
Bläckberg, L.; El Fakhri, G.; Sabet, H.
2017-11-01
A tightly focused pulsed laser beam can locally modify the crystal structure inside the bulk of a scintillator. The result is incorporation of so-called optical barriers with a refractive index different from that of the crystal bulk, that can be used to redirect the scintillation light and control the light spread in the detector. We here systematically study the scintillation light transport in detectors fabricated using the laser induced optical barrier technique, and objectively compare their potential performance characteristics with those of the two mainstream detector types: monolithic and mechanically pixelated arrays. Among countless optical barrier patterns, we explore barriers arranged in a pixel-like pattern extending all-the-way or half-way through a 20 mm thick LYSO:Ce crystal. We analyze the performance of the detectors coupled to MPPC arrays, in terms of light response functions, flood maps, line profiles, and light collection efficiency. Our results show that laser-processed detectors with both barrier patterns constitute a new detector category with a behavior between that of the two standard detector types. Results show that when the barrier-crystal interface is smooth, no DOI information can be obtained regardless of barrier refractive index (RI). However, with a rough barrier-crystal interface we can extract multiple levels of DOI. Lower barrier RI results in larger light confinement, leading to better transverse resolution. Furthermore we see that the laser-processed crystals have the potential to increase the light collection efficiency, which could lead to improved energy resolution and potentially better timing resolution due to higher signals. For a laser-processed detector with smooth barrier-crystal interfaces the light collection efficiency is simulated to >42%, and for rough interfaces >73%. The corresponding numbers for a monolithic crystal is 39% with polished surfaces, and 71% with rough surfaces, and for a mechanically pixelated array 35% with polished pixel surfaces and 59% with rough surfaces.
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Simulation study of light transport in laser-processed LYSO:Ce detectors with single-side readout.
Bläckberg, L; El Fakhri, G; Sabet, H
2017-10-19
A tightly focused pulsed laser beam can locally modify the crystal structure inside the bulk of a scintillator. The result is incorporation of so-called optical barriers with a refractive index different from that of the crystal bulk, that can be used to redirect the scintillation light and control the light spread in the detector. We here systematically study the scintillation light transport in detectors fabricated using the laser induced optical barrier technique, and objectively compare their potential performance characteristics with those of the two mainstream detector types: monolithic and mechanically pixelated arrays. Among countless optical barrier patterns, we explore barriers arranged in a pixel-like pattern extending all-the-way or half-way through a 20 mm thick LYSO:Ce crystal. We analyze the performance of the detectors coupled to MPPC arrays, in terms of light response functions, flood maps, line profiles, and light collection efficiency. Our results show that laser-processed detectors with both barrier patterns constitute a new detector category with a behavior between that of the two standard detector types. Results show that when the barrier-crystal interface is smooth, no DOI information can be obtained regardless of barrier refractive index (RI). However, with a rough barrier-crystal interface we can extract multiple levels of DOI. Lower barrier RI results in larger light confinement, leading to better transverse resolution. Furthermore we see that the laser-processed crystals have the potential to increase the light collection efficiency, which could lead to improved energy resolution and potentially better timing resolution due to higher signals. For a laser-processed detector with smooth barrier-crystal interfaces the light collection efficiency is simulated to >42%, and for rough interfaces >73%. The corresponding numbers for a monolithic crystal is 39% with polished surfaces, and 71% with rough surfaces, and for a mechanically pixelated array 35% with polished pixel surfaces and 59% with rough surfaces.
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Morphology, structure and optical properties of hydrothermally synthesized CeO2/CdS nanocomposites
NASA Astrophysics Data System (ADS)
Mohanty, Biswajyoti; Nayak, J.
2018-04-01
CeO2/CdS nanocomposites were synthesized using a two-step hydrothermal technique. The effects of precursor concentration on the optical and structural properties of the CeO2/CdS nanoparticles were systematically studied. The morphology, composition and the structure of the CeO2/CdS nanocomposite powder were studied by scanning electron microscopy (SEM), energy dispersive X-ray spectrum analysis (EDXA) and X-ray diffraction (XRD), respectively. The optical properties of CeO2/CdS nanocomposites were studied by UV-vis absorption and photoluminescence (PL) spectroscopy. The optical band gaps of the CeO2/CdS nanopowders ranged from 2.34 eV to 2.39 eV as estimated from the UV-vis absorption. In the room temperature photoluminescence spectrum of CeO2/CdS nanopowder, a strong blue emission band was observed at 400 nm. Since the powder shows strong visible luminescence, it may be used as a blue phosphor in future. The original article published with this DOI was submitted in error. The correct article was inadvertently left out of the original submission. This has been rectified and the correct article was published online on 16 April 2018.
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Long-distance Dating: In situ geochronology for planetary missions
NASA Astrophysics Data System (ADS)
Cho, Y.; Cohen, B. A.
2016-12-01
Isotopic dating is an essential tool to establish an absolute chronology for geological events. It enables a planet's crystallization history, magmatic evolution, and alteration to be placed into the framework of solar system history. The capability for in situ geochronology will open up the ability for this crucial measurement to be accomplished as part of lander or rover complement. An in situ geochronology package can also complement sample return missions by identifying the most interesting rocks to cache or return to Earth. The capability of flight instruments to conduct in situ geochronology is called out in the NASA Planetary Science Decadal Survey and the NASA Technology Roadmap as needing development to serve the community's needs. Beagle 2 is the only mission launched to date with the explicit aim to perform in situ K-Ar isotopic dating [1], but it failed to communicate and was lost. The first in situ K-Ar date on Mars, using SAM and APXS measurements on the Cumberland mudstone [2], yielded an age of 4.21 ± 0.35 Ga and validated the idea of K-Ar dating on other planets, though the Curiosity method is not purpose-built for dating and requires many assumptions that degrade its precision. To get more precise and meaningful ages, multiple groups are developing dedicated in situ dating instruments [3-7], including the K-Ar Laser Experiment (KArLE) [5]. KArLE ablates a rock sample, measures K using laser-induced breakdown spectroscopy (LIBS), measures liberated Ar using mass spectrometry (MS), and relates the two by measuring the volume of the ablated pit with optical imaging. The KArLE breadboard tested planetary analog samples yielding ages with 25% uncertainty on very young samples (<50Ma) and 10% uncertainties on older samples. [1] Talboys, et al. (2009) Planetary and Space Science 57, 1237-1245, doi:10.1016/j.pss.2009.02.012. [2] Farley, et al. (2014) Science 343, doi:10.1126/science.1247166. [3] Anderson, et al. (2015) Rapid Comm. Mass Spec. 29, 191-204, doi:10.1002/rcm.7095. [4] Solé (2014) Chem. Geo. doi: 10.1016/j.chemgeo.2014.08.027. [5] Cohen, et al. (2014) Geostand. Geoanaly. Res. 38, 421-439, doi:10.1111/j.1751-908X.2014.00319.x. [6] Farley, et al. (2013) Geochim. Cosmochim. Acta 110, 1-12, doi:10.1016/j.gca.2013.02.010. [7] Cho, et al. (2016) Planet. Space Sci. 128, 14-29.
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ROBUST hot wire probe efficiency for total water content measurements in glaciated conditions
NASA Astrophysics Data System (ADS)
Leroy, Delphine; Lilie, Lyle; Weber, Marc; Schwarzenboeck, Alfons; Strapp, J. Walter
2017-04-01
During the two High Altitude Ice Crystals (HAIC, Dezitter et al. 2013)/High Ice Water Content (HIWC, Strapp et al., 2016a) international flight campaigns that investigated deep convection in the tropics, the French Falcon 20 research aircraft was equipped with two different devices measuring the Total Water Content (TWC): - the IKP-2 (Isokinetic Probe, Davison et al. 2008, 2016), - and the hot wire ROBUST probe (Strapp et al. 2008; Grandin et al. 2014). The IKP-2 probe is an evaporator that has been specifically designed to measure high ice water content (Strapp et al. 2016b) with a collection efficiency near unity. It has undergone extensive performance assessment in liquid and glaciated conditions in several wind tunnels. The Robust probe was initially developed by Science Engineering Associates to estimate high ice water content in a high speed wind tunnel, in harsh conditions where other hot-wires had been observed to suffer failures. It was known at the outset that, like other hot-wire TWC probes, it would measure only a quasi-constant fraction of the true ice water content. Early wind tunnel and flight experience with the ROBUST probe revealed that this fraction was the order of 40% for ice crystals. During the HAIC/HIWC campaigns (Leroy et al. 2016, 2017), supercooled liquid water conditions were documented according to a detailed analysis of a Rosemount Ice detector (RICE) and a Cloud Droplet Probe (CDP) measurements, and were found to be rare. Thus, the HAIC/HIWC dataset represents a unique opportunity to study in more detail the ROBUST efficiency in glaciated conditions, using the IKP-2 values as a comparative reference. Comparison of IKP-2 and ROBUST measurements will show that the ROBUST behavior differs between low (below 1.5 g/m3) and high (above 2 g/m3) ice content conditions and is also sensitive to temperature. The sensitivity of the ROBUST collection efficiency to ice particles size could also be explored as optical imaging probes were part of the airborne instrument package but no clear trend has been highlighted for the moment. References : Davison, C., J. MacLeod, J. Strapp, and D. Buttsworth, 2008: Isokinetic Total Water Content Probe in a Naturally Aspirating Configuration: Initial Aerodynamic Design and Testing. 46th AIAA Aerospace Sciences Meeting and Exhibit, American Institute of Aeronautics and Astronautics http://arc.aiaa.org/doi/abs/10.2514/6.2008-435 (Accessed February 9, 2015). Davison, C. R., J. W. Strapp, L. E. Lilie, T. P. Ratvasky, and C. Dumont, 2016: Isokinetic TWC Evaporator Probe: Calculations and Systemic Error Analysis. American Institute of Aeronautics and Astronautics http://arc.aiaa.org/doi/10.2514/6.2016-4060 (Accessed July 29, 2016). Dezitter, F., A. Grandin, J.-L. Brenguier, F. Hervy, H. Schlager, P. Villedieu, and G. Zalamansky, 2013: HAIC - High Altitude Ice Crystals. 5th AIAA Atmospheric and Space Environments Conference, American Institute of Aeronautics and Astronautics http://arc.aiaa.org/doi/abs/10.2514/6.2013-2674 (Accessed February 9, 2015). Grandin, A., J.-M. Merle, M. Weber, J. Strapp, A. Protat, and P. King, 2014: AIRBUS Flight Tests in High Total Water Content Regions. American Institute of Aeronautics and Astronautics http://arc.aiaa.org/doi/abs/10.2514/6.2014-2753 (Accessed March 8, 2016). Leroy, D., and Coauthors, 2016: HAIC/HIWC field campaigns - Specific findings on ice crystals characteristics in high ice water content cloud regions. American Institute of Aeronautics and Astronautics http://arc.aiaa.org/doi/10.2514/6.2016-4056 (Accessed January 10, 2017). Leroy, D., and Coauthors, 2017: Ice Crystal Sizes in High Ice Water Content Clouds. Part II: Statistics of Mass Diameter Percentiles in Tropical Convection Observed during the HAIC/HIWC Project. J. Atmospheric Ocean. Technol., 34, 117-136, doi:10.1175/JTECH-D-15-0246.1. Strapp, J. W., J. MacLeod, and L. Lilie, 2008: Calibration of ice water content in a wind tunnel/engine test cell facility. 15th Intl. Conf. on Cloud and Precipitation http://cabernet.atmosfcu.unam.mx/ICCP-2008/abstracts/Program_on_line/Poster_13/StrappEtAl-extended.pdf (Accessed April 25, 2016). Strapp, J. W., L. E. Lilie, T. P. Ratvasky, C. R. Davison, and C. Dumont, 2016b: Isokinetic TWC Evaporator Probe: Development of the IKP2 and Performance Testing for the HAIC-HIWC Darwin 2014 and Cayenne Field Campaigns. American Institute of Aeronautics and Astronautics http://arc.aiaa.org/doi/10.2514/6.2016-4059 (Accessed July 29, 2016). Strapp, J. W., G. A. Isaac. A. Korolev, T. Ratvasky, R. Potts, P. May, A. Protat, P. Minnis, A. Ackerman, A. Fridlind, J. Haggerty, and J. Riley, 2016a: The High Ice Water Content (HIWC) Study of deep convective clouds: Science and technical plan. FAA Rep. DOT/FAA/TC-14/31, available at http://www.tc.faa.gov/its/worldpac/techrpt/tc14-31.pdf. 105 pgs.
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Translation of 5′ leaders is pervasive in genes resistant to eIF2 repression
Fahey, Ciara; Kenny, Elaine M; Terenin, Ilya M; Dmitriev, Sergey E; Cormican, Paul; Morris, Derek W; Shatsky, Ivan N; Baranov, Pavel V
2015-01-01
Eukaryotic cells rapidly reduce protein synthesis in response to various stress conditions. This can be achieved by the phosphorylation-mediated inactivation of a key translation initiation factor, eukaryotic initiation factor 2 (eIF2). However, the persistent translation of certain mRNAs is required for deployment of an adequate stress response. We carried out ribosome profiling of cultured human cells under conditions of severe stress induced with sodium arsenite. Although this led to a 5.4-fold general translational repression, the protein coding open reading frames (ORFs) of certain individual mRNAs exhibited resistance to the inhibition. Nearly all resistant transcripts possess at least one efficiently translated upstream open reading frame (uORF) that represses translation of the main coding ORF under normal conditions. Site-specific mutagenesis of two identified stress resistant mRNAs (PPP1R15B and IFRD1) demonstrated that a single uORF is sufficient for eIF2-mediated translation control in both cases. Phylogenetic analysis suggests that at least two regulatory uORFs (namely, in SLC35A4 and MIEF1) encode functional protein products. DOI: http://dx.doi.org/10.7554/eLife.03971.001 PMID:25621764
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Hubin, Elizabeth A; Fay, Allison; Xu, Catherine; Bean, James M; Saecker, Ruth M; Glickman, Michael S; Darst, Seth A; Campbell, Elizabeth A
2017-01-01
RbpA and CarD are essential transcription regulators in mycobacteria. Mechanistic analyses of promoter open complex (RPo) formation establish that RbpA and CarD cooperatively stimulate formation of an intermediate (RP2) leading to RPo; formation of RP2 is likely a bottleneck step at the majority of mycobacterial promoters. Once RPo forms, CarD also disfavors its isomerization back to RP2. We determined a 2.76 Å-resolution crystal structure of a mycobacterial transcription initiation complex (TIC) with RbpA as well as a CarD/RbpA/TIC model. Both CarD and RbpA bind near the upstream edge of the −10 element where they likely facilitate DNA bending and impede transcription bubble collapse. In vivo studies demonstrate the essential role of RbpA, show the effects of RbpA truncations on transcription and cell physiology, and indicate additional functions for RbpA not evident in vitro. This work provides a framework to understand the control of mycobacterial transcription by RbpA and CarD. DOI: http://dx.doi.org/10.7554/eLife.22520.001 PMID:28067618
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Fast retrieval and autonomous regulation of single spontaneously recycling synaptic vesicles
Leitz, Jeremy; Kavalali, Ege T
2014-01-01
Presynaptic terminals release neurotransmitters spontaneously in a manner that can be regulated by Ca2+. However, the mechanisms underlying this regulation are poorly understood because the inherent stochasticity and low probability of spontaneous fusion events has curtailed their visualization at individual release sites. Here, using pH-sensitive optical probes targeted to synaptic vesicles, we visualized single spontaneous fusion events and found that they are retrieved extremely rapidly with faster re-acidification kinetics than their action potential-evoked counterparts. These fusion events were coupled to postsynaptic NMDA receptor-driven Ca2+ signals, and at elevated Ca2+ concentrations there was an increase in the number of vesicles that would undergo fusion. Furthermore, spontaneous vesicle fusion propensity in a synapse was Ca2+-dependent but regulated autonomously: independent of evoked fusion probability at the same synapse. Taken together, these results expand classical quantal analysis to incorporate endocytic and exocytic phases of single fusion events and uncover autonomous regulation of spontaneous fusion. DOI: http://dx.doi.org/10.7554/eLife.03658.001 PMID:25415052
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Thompson, Karen J; Harley, Cynthia M; Barthel, Grant M; Sanders, Mark A; Mesce, Karen A
2015-01-01
The staining of neurons with silver began in the 1800s, but until now the great resolving power of the laser scanning confocal microscope has not been utilized to capture the in-focus and three-dimensional cytoarchitecture of metal-impregnated cells. Here, we demonstrate how spectral confocal microscopy, typically reserved for fluorescent imaging, can be used to visualize metal-labeled tissues. This imaging does not involve the reflectance of metal particles, but rather the excitation of silver (or gold) nanoparticles and their putative surface plasmon resonance. To induce such resonance, silver or gold particles were excited with visible-wavelength laser lines (561 or 640 nm), and the maximal emission signal was collected at a shorter wavelength (i.e., higher energy state). Because the surface plasmon resonances of noble metal nanoparticles offer a superior optical signal and do not photobleach, our novel protocol holds enormous promise of a rebirth and further development of silver- and gold-based cell labeling protocols. DOI: http://dx.doi.org/10.7554/eLife.09388.001 PMID:26670545
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Tsunoda, Satoshi; Avezov, Edward; Zyryanova, Alisa; Konno, Tasuku; Mendes-Silva, Leonardo; Pinho Melo, Eduardo; Harding, Heather P; Ron, David
2014-01-01
Protein folding homeostasis in the endoplasmic reticulum (ER) requires efficient protein thiol oxidation, but also relies on a parallel reductive process to edit disulfides during the maturation or degradation of secreted proteins. To critically examine the widely held assumption that reduced ER glutathione fuels disulfide reduction, we expressed a modified form of a cytosolic glutathione-degrading enzyme, ChaC1, in the ER lumen. ChaC1CtoS purged the ER of glutathione eliciting the expected kinetic defect in oxidation of an ER-localized glutathione-coupled Grx1-roGFP2 optical probe, but had no effect on the disulfide editing-dependent maturation of the LDL receptor or the reduction-dependent degradation of misfolded alpha-1 antitrypsin. Furthermore, glutathione depletion had no measurable effect on induction of the unfolded protein response (UPR); a sensitive measure of ER protein folding homeostasis. These findings challenge the importance of reduced ER glutathione and suggest the existence of alternative electron donor(s) that maintain the reductive capacity of the ER. DOI: http://dx.doi.org/10.7554/eLife.03421.001 PMID:25073928
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Examining kinesin processivity within a general gating framework
Andreasson, Johan OL; Milic, Bojan; Chen, Geng-Yuan; Guydosh, Nicholas R; Hancock, William O; Block, Steven M
2015-01-01
Kinesin-1 is a dimeric motor that transports cargo along microtubules, taking 8.2-nm steps in a hand-over-hand fashion. The ATP hydrolysis cycles of its two heads are maintained out of phase by a series of gating mechanisms, which lead to processive runs averaging ∼1 μm. A key structural element for inter-head coordination is the neck linker (NL), which connects the heads to the stalk. To examine the role of the NL in regulating stepping, we investigated NL mutants of various lengths using single-molecule optical trapping and bulk fluorescence approaches in the context of a general framework for gating. Our results show that, although inter-head tension enhances motor velocity, it is crucial neither for inter-head coordination nor for rapid rear-head release. Furthermore, cysteine-light mutants do not produce wild-type motility under load. We conclude that kinesin-1 is primarily front-head gated, and that NL length is tuned to enhance unidirectional processivity and velocity. DOI: http://dx.doi.org/10.7554/eLife.07403.001 PMID:25902401
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Chamberland, Simon; Yang, Helen H; Pan, Michael M; Evans, Stephen W; Guan, Sihui; Chavarha, Mariya; Yang, Ying; Salesse, Charleen; Wu, Haodi; Wu, Joseph C; Clandinin, Thomas R; Toth, Katalin; Lin, Michael Z; St-Pierre, François
2017-01-01
Monitoring voltage dynamics in defined neurons deep in the brain is critical for unraveling the function of neuronal circuits but is challenging due to the limited performance of existing tools. In particular, while genetically encoded voltage indicators have shown promise for optical detection of voltage transients, many indicators exhibit low sensitivity when imaged under two-photon illumination. Previous studies thus fell short of visualizing voltage dynamics in individual neurons in single trials. Here, we report ASAP2s, a novel voltage indicator with improved sensitivity. By imaging ASAP2s using random-access multi-photon microscopy, we demonstrate robust single-trial detection of action potentials in organotypic slice cultures. We also show that ASAP2s enables two-photon imaging of graded potentials in organotypic slice cultures and in Drosophila. These results demonstrate that the combination of ASAP2s and fast two-photon imaging methods enables detection of neural electrical activity with subcellular spatial resolution and millisecond-timescale precision. DOI: http://dx.doi.org/10.7554/eLife.25690.001 PMID:28749338
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Massive palmitoylation-dependent endocytosis during reoxygenation of anoxic cardiac muscle
Lin, Mei-Jung; Fine, Michael; Lu, Jui-Yun; Hofmann, Sandra L; Frazier, Gary; Hilgemann, Donald W
2013-01-01
In fibroblasts, large Ca transients activate massive endocytosis (MEND) that involves membrane protein palmitoylation subsequent to mitochondrial permeability transition pore (PTP) openings. Here, we characterize this pathway in cardiac muscle. Myocytes with increased expression of the acyl transferase, DHHC5, have decreased Na/K pump activity. In DHHC5-deficient myocytes, Na/K pump activity and surface area/volume ratios are increased, the palmitoylated regulatory protein, phospholemman (PLM), and the cardiac Na/Ca exchanger (NCX1) show greater surface membrane localization, and MEND is inhibited in four protocols. Both electrical and optical methods demonstrate that PTP-dependent MEND occurs during reoxygenation of anoxic hearts. Post-anoxia MEND is ablated in DHHC5-deficient hearts, inhibited by cyclosporine A (CsA) and adenosine, promoted by staurosporine (STS), reduced in hearts lacking PLM, and correlates with impaired post-anoxia contractile function. Thus, the MEND pathway appears to be deleterious in severe oxidative stress but may constitutively contribute to cardiac sarcolemma turnover in dependence on metabolic stress. DOI: http://dx.doi.org/10.7554/eLife.01295.001 PMID:24282237
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NASA Astrophysics Data System (ADS)
Wang, Zhenguang; Susha, Andrei S.; Chen, Bingkun; Reckmeier, Claas; Tomanec, Ondrej; Zboril, Radek; Zhong, Haizheng; Rogach, Andrey L.
2016-03-01
Poly(vinylpyrrolidone) supported Cu nanoclusters were synthesized by reduction of Cu(ii) ions with ascorbic acid in water, and initially showed blue photoluminescence with a quantum yield of 8%. An enhancement of the emission quantum yield has been achieved by treatment of Cu clusters with different electron-rich ligands, with the most pronounced effect (photoluminescence quantum yield of 27%) achieved with glutathione. The bright blue emission of glutathione treated Cu NCs is fully preserved in the solid state powder, which has been combined with commercial green and red phosphors to fabricate down-conversion white light emitting diodes with a high colour rendering index of 92.Poly(vinylpyrrolidone) supported Cu nanoclusters were synthesized by reduction of Cu(ii) ions with ascorbic acid in water, and initially showed blue photoluminescence with a quantum yield of 8%. An enhancement of the emission quantum yield has been achieved by treatment of Cu clusters with different electron-rich ligands, with the most pronounced effect (photoluminescence quantum yield of 27%) achieved with glutathione. The bright blue emission of glutathione treated Cu NCs is fully preserved in the solid state powder, which has been combined with commercial green and red phosphors to fabricate down-conversion white light emitting diodes with a high colour rendering index of 92. Electronic supplementary information (ESI) available: The optical spectra of control experiments for Cu NC synthesis, optimization of the reaction conditions, and spectra for LEDs chips and blue LEDs. See DOI: 10.1039/c6nr00806b
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Highly improved operation of monolithic BGO-PET blocks
NASA Astrophysics Data System (ADS)
Gonzalez-Montoro, A.; Sanchez, F.; Majewski, S.; Zanettini, S.; Benlloch, J. M.; Gonzalez, A. J.
2017-11-01
In PET scanners both scintillation crystals and photosensors are key components defining the system's performance and cost. Original PET systems used BGO or NaI(Tl) scintillators but achieved limited performance due to its slow decay and relatively low light output. Moreover, NaI(Tl) has low stopping power for 511 keV annihilation photons. In this study we report the possibility to reintroduce BGO crystals, and in particular in the form of monolithic blocks, especially suitable for low-dose large-size PET scanners, offering significantly improved sensitivity at a highly reduced cost compared to LYSO type fast scintillators. We have studied the performance of a monolithic BGO block as large as 50 × 50 × 15 mm3 with black-painted lateral walls to reduce lights spread, enabling accurate photon depth of interaction (DOI) measurements. A directional optical layer, called retro-reflector, was coupled to the entrance face bouncing back the scintillation light in the direction of the emission source and, therefore, adding to the light signal while preserving the narrow light cone distribution. Four configurations namely 12 × 12 and 16 × 16 SiPM arrays (3 mm × 3 mm each) as photosensors, with or without a nanopattern treatment at the crystal exit face, have been studied. This structure consisted of a thin layer of a specific high refractive index material shaped with a periodic nanopattern, increasing the scintillation light extraction. The readout returned information for each SiPM row and column, characterizing the X-Y light distribution projections. We have studied the detector spatial resolution using collimated 22Na sources at normal incidence. The DOI resolution was evaluated using collimated gamma beams with lateral incidence. The overall best detector performance was obtained for the 16× 16 SiPM array offering higher readout granularity. We have determined the spatial resolution for 3 separated DOI layers, obtaining the best results for the DOI region near to the photosensor.
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NASA Astrophysics Data System (ADS)
Oshikane, Yasushi; Murai, Kensuke; Nakano, Motohiro
2013-09-01
We have been studied a finite asymmetric metal-insulator-metal (MIM) structure on glass plate for near-future visible light communication (VLC) system with white LED illuminations in the living space (DOI: 10.1117/12.929201). The metal layers are vacuum-evaporated thin silver (Ag) films (around 50 nm and 200 nm, respectively), and the insulator layer (around 150 nm) is composed of magnesium fluoride (MgF2). A characteristic narrow band filtering of the MIM structure at visible region might cause a confinement of intense surface plasmon polaritons (SPPs) at specific monochromatic frequency inside a subwavelength insulator layer of the MIM structure. Central wavelength and depth of such absorption dip in flat spectral reflectance curve is controlled by changing thicknesses of both insulator and thinner metal layers. On the other hand, we have proposed a twin-hole pass-through wave guide for SPPs in thick Ag film (DOI: 10.1117/12.863587). At that time, the twin-hole converted a incoming plane light wave into a pair of channel plasmon polaritons (CPPs), and united them at rear surface of the Ag film. This research is having an eye to extract, guide, and focus the SPPs through a thicker metal layer of the MIM with FIBed subwavelength pass-through holes. The expected outcome is a creation of noble, monochromatic, and tunable fiber probe for scanning near-field optical microscopes (SNOMs) with intense white light sources. Basic experimental and FEM simulation results will be presented.
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Featured Image: Identifying a Glowing Shell
NASA Astrophysics Data System (ADS)
Kohler, Susanna
2018-05-01
New nebulae are being discovered and classified every day and this false-color image reveals one of the more recent objects of interest. This nebula, IPHASX J210204.7+471015, was recently imaged by the Andalucia Faint Object Spectrograph and Camera mounted on the 2.5-m Nordic Optical Telescope in La Palma, Spain. J210204 was initially identified as a possible planetary nebula a remnant left behind at the end of a red giants lifetime. Based on the above imaging, however, a team of authors led by Martn Guerrero (Institute of Astrophysics of Andalusia, Spain) is arguing that this shell of glowing gas was instead expelled around a classical nova. In a classical nova eruption, a white dwarf and its binary companion come very close together, and mass transfers to form a thin atmosphere of hydrogen around the white dwarf. When this hydrogen suddenly ignites in runaway fusion, this outer atmosphere can be expelled, forming a short-lived nova remnant which is what Guerrero and collaborators think were seeing with J210204. If so, this nebula can reveal information about the novathat caused it. To find out more about what the authors learned from this nebula, check out the paper below.CitationMartn A. Guerrero et al 2018 ApJ 857 80. doi:10.3847/1538-4357/aab669
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Watanabe, Satoru; Ozawa, Hiroaki; Kato, Hiroaki; Nimura-Matsune, Kaori; Hirayama, Toshifumi; Kudo, Fumitaka; Eguchi, Tadashi; Kakinuma, Katsumi; Yoshikawa, Hirofumi
2018-01-01
Owing to their photosynthetic capabilities, there is increasing interest in utilizing cyanobacteria to convert solar energy into biomass. 2-Deoxy-scyllo-inosose (DOI) is a valuable starting material for the benzene-free synthesis of catechol and other benzenoids. DOI synthase (DOIS) is responsible for the formation of DOI from d-glucose-6-phosphate (G6P) in the biosynthesis of 2-deoxystreptamine-containing aminoglycoside antibiotics such as neomycin and butirosin. DOI fermentation using a recombinant Escherichia coli strain has been reported, although a carbon source is necessary for high-yield DOI production. We constructed DOI-producing cyanobacteria toward carbon-free and sustainable DOI production. A DOIS gene derived from the butirosin producer strain Bacillus circulans (btrC) was introduced and expressed in the cyanobacterium Synechococcus elongatus PCC 7942. We ultimately succeeded in producing 400 mg/L of DOI in S. elongatus without using a carbon source. DOI production by cyanobacteria represents a novel and efficient approach for producing benzenoids from G6P synthesized by photosynthesis.
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Process Architecture for Managing Digital Object Identifiers
NASA Astrophysics Data System (ADS)
Wanchoo, L.; James, N.; Stolte, E.
2014-12-01
In 2010, NASA's Earth Science Data and Information System (ESDIS) Project implemented a process for registering Digital Object Identifiers (DOIs) for data products distributed by Earth Observing System Data and Information System (EOSDIS). For the first 3 years, ESDIS evolved the process involving the data provider community in the development of processes for creating and assigning DOIs, and guidelines for the landing page. To accomplish this, ESDIS established two DOI User Working Groups: one for reviewing the DOI process whose recommendations were submitted to ESDIS in February 2014; and the other recently tasked to review and further develop DOI landing page guidelines for ESDIS approval by end of 2014. ESDIS has recently upgraded the DOI system from a manually-driven system to one that largely automates the DOI process. The new automated feature include: a) reviewing the DOI metadata, b) assigning of opaque DOI name if data provider chooses, and c) reserving, registering, and updating the DOIs. The flexibility of reserving the DOI allows data providers to embed and test the DOI in the data product metadata before formally registering with EZID. The DOI update process allows the changing of any DOI metadata except the DOI name unless the name has not been registered. Currently, ESDIS has processed a total of 557 DOIs of which 379 DOIs are registered with EZID and 178 are reserved with ESDIS. The DOI incorporates several metadata elements that effectively identify the data product and the source of availability. Of these elements, the Uniform Resource Locator (URL) attribute has the very important function of identifying the landing page which describes the data product. ESDIS in consultation with data providers in the Earth Science community is currently developing landing page guidelines that specify the key data product descriptive elements to be included on each data product's landing page. This poster will describe in detail the unique automated process and underlying system implemented by ESDIS for registering DOIs, as well as some of the lessons learned from the development of the process. In addition, this paper will summarize the recommendations made by the DOI Process and DOI Landing Page User Working Groups, and the procedures developed for implementing those recommendations.
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McLeod, Stephen D.
2006-01-01
Purpose To design and develop an accommodating intraocular lens (IOL) for endocapsular fixation with extended accommodative range that can be adapted to current standard extracapsular phacoemulsification technique. Methods Ray tracing analysis and lens design; finite element modeling of biomechanical properties; cadaver eye implantation; initial clinical evaluation. Results Ray tracing analysis indicated that a dual-optic design with a high plus-power front optic coupled to an optically compensatory minus posterior optic produced greater change in conjugation power of the eye compared to that produced by axial movement of a single-optic IOL, and that magnification effects were unlikely to account for improved near vision. Finite element modeling indicated that the two optics can be linked by spring-loaded haptics that allow anterior and posterior axial displacement of the front optic in response to changes in ciliary body tone and capsular tension. A dual-optic single-piece foldable silicone lens was constructed based on these principles. Subsequent initial clinical evaluation in 24 human eyes after phacoemulsification for cataract indicated mean 3.22 diopters of accommodation (range, 1 to 5 D) based on defocus curve measurement. Accommodative amplitude evaluation at 1- and 6-month follow-up in all eyes indicated that the accommodative range was maintained and that the lens was well tolerated. Conclusions A dual-optic design increases the accommodative effect of axial optic displacement, with minimal magnification effect. Initial clinical trials suggest that IOLs designed on this principle might provide true pseudophakic accommodation following cataract extraction and lens implantation. PMID:17471355
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NASA Astrophysics Data System (ADS)
Khoder, Mulham; Van der Sande, Guy; Danckaert, Jan; Verschaffelt, Guy
2016-05-01
It is well known that the performance of semiconductor lasers is very sensitive to external optical feedback. This feedback can lead to changes in lasing characteristics and a variety of dynamical effects including chaos and coherence collapse. One way to avoid this external feedback is by using optical isolation, but these isolators and their packaging will increase the cost of the total system. Semiconductor ring lasers nowadays are promising sources in photonic integrated circuits because they do not require cleaved facets or mirrors to form a laser cavity. Recently, some of us proposed to combine semiconductor ring lasers with on chip filtered optical feedback to achieve tunable lasers. The feedback is realized by employing two arrayed waveguide gratings to split/recombine light into different wavelength channels. Semiconductor optical amplifier gates are used to control the feedback strength. In this work, we investigate how such lasers with filtered feedback are influenced by an external conventional optical feedback. The experimental results show intensity fluctuations in the time traces in both the clockwise and counterclockwise directions due to the conventional feedback. We quantify the strength of the conventional feedback induced dynamics be extracting the standard deviation of the intensity fluctuations in the time traces. By using filtered feedback, we can shift the onset of the conventional feedback induced dynamics to larger values of the feedback rate [ Khoder et al, IEEE Photon. Technol. Lett. DOI: 10.1109/LPT.2016.2522184]. The on-chip filtered optical feedback thus makes the semiconductor ring laser less senstive to the effect of (long) conventional optical feedback. We think these conclusions can be extended to other types of lasers.
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Wang, W. C.; Le, Q. H.; Zhang, Q. Y.
2017-01-01
Unusually stable multi-anion glasses of the fluoride-sulfophosphate type (FPS) are introduced as a new host material for optically active cation species. Despite a notoriously low polymerization grade, anion mixing in this glass system enables facile manufacture of bulk or fiber devices which combine several advantages of fluoride and phosphate glasses while using the stabilizing effect of sulfate additions. Using the example of chromium doping, we demonstrate broad red photoluminescence at 734 nm and inhomogeneous broadening of the R-line at 694 nm, originating from the 4T2 → 4A2 and 2E → 4A2 transitions of Cr3+, respectively. The luminescence mechanism is further analyzed on the basis of the corresponding Tanabe–Sugano diagram. Tailored through chemical composition, internally nucleated precipitation of a nanocrystalline fluoride phase enables switching between high-field and low-field configurations of the Cr3+ ion, resulting in the specific emission properties and setting the path towards FPS-based optical devices. PMID:29308205
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Cylindrical Organic Solar Cells with Carbon Nanotube Charge Collectors
NASA Astrophysics Data System (ADS)
Zakhidov, Dante; Lou, Raymond; Ravi, Nav; Mielczarek, Kamil; Cook, Alexander
2009-10-01
Traditional organic photovoltaic devices (OPV) are built on a flat glass substrates coated by ITO. The maximum area covered by the solar cells is limited to a two dimensional plane. Moreover the light absorption is not maximized for a very thin photoactive layer. We suggest here a cylindrical design which has a vertical structure of optical fiber coated by OPV, with light incident from the side and from edge. The sunlight, entering via a smaller area is captured into optical fiber, which allows more sunlight to be absorbed by a cylindrical OPV overcoating with multiple reflections inside the optical fiber. Instead of using brittle ITO as a hole collecting layer in the cylindrical OPV, transparent sheets of multi-walled carbon nanotubes are applied. Their highly conductive nature and 3-D collection of carriers from the P3HT/PCBM photoactive layer allows for increased efficiency over a planar geometry while keeping the device transparent. Aluminum is used as the electron collecting layer and as a cylindrical mirror. [4pt] [1] Ulbricht, et.al, phys. stat. sol. (b) 243, No. 13, 3528 - 3532 (2006) / DOI 10.1002/pssb.200669181
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Water-soluble nanocrystalline cellulose films with highly transparent and oxygen barrier properties
NASA Astrophysics Data System (ADS)
Cheng, Shaoling; Zhang, Yapei; Cha, Ruitao; Yang, Jinliang; Jiang, Xingyu
2015-12-01
By mixing a guar gum (GG) solution with a nanocrystalline cellulose (NCC) dispersion using a novel circular casting technology, we manufactured biodegradable films as packaging materials with improved optical and mechanical properties. These films could act as barriers for oxygen and could completely dissolve in water within 5 h. We also compared the effect of nanocomposite films and commercial food packaging materials on the preservation of food.By mixing a guar gum (GG) solution with a nanocrystalline cellulose (NCC) dispersion using a novel circular casting technology, we manufactured biodegradable films as packaging materials with improved optical and mechanical properties. These films could act as barriers for oxygen and could completely dissolve in water within 5 h. We also compared the effect of nanocomposite films and commercial food packaging materials on the preservation of food. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr07647a
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Exploring luminescence-based temperature sensing using protein-passivated gold nanoclusters
NASA Astrophysics Data System (ADS)
Chen, Xi; Essner, Jeremy B.; Baker, Gary A.
2014-07-01
We explore the analytical performance and limitations of optically monitoring aqueous-phase temperature using protein-protected gold nanoclusters (AuNCs). Although not reported elsewhere, we find that these bio-passivated AuNCs show pronounced hysteresis upon thermal cycling. This unwanted behaviour can be eliminated by several strategies, including sol-gel coating and thermal denaturation of the biomolecular template, introducing protein-templated AuNC probes as viable nanothermometers.We explore the analytical performance and limitations of optically monitoring aqueous-phase temperature using protein-protected gold nanoclusters (AuNCs). Although not reported elsewhere, we find that these bio-passivated AuNCs show pronounced hysteresis upon thermal cycling. This unwanted behaviour can be eliminated by several strategies, including sol-gel coating and thermal denaturation of the biomolecular template, introducing protein-templated AuNC probes as viable nanothermometers. Electronic supplementary information (ESI) available: Supplemental figures and experimental details. See DOI: 10.1039/c4nr02069c
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NASA Astrophysics Data System (ADS)
Sotiropoulou, R. P.; Meshkhidze, N.; Nenes, A.
2006-12-01
The aerosol indirect forcing is one of the largest sources of uncertainty in assessments of anthropogenic climate change [IPCC, 2001]. Much of this uncertainty arises from the approach used for linking cloud droplet number concentration (CDNC) to precursor aerosol. Global Climate Models (GCM) use a wide range of cloud droplet activation mechanisms ranging from empirical [Boucher and Lohmann, 1995] to detailed physically- based formulations [e.g., Abdul-Razzak and Ghan, 2000; Fountoukis and Nenes, 2005]. The objective of this study is to assess the uncertainties in indirect forcing and autoconversion of cloud water to rain caused by the application of different cloud droplet parameterization mechanisms; this is an important step towards constraining the aerosol indirect effects (AIE). Here we estimate the uncertainty in indirect forcing and autoconversion rate using the NASA Global Model Initiative (GMI). The GMI allows easy interchange of meteorological fields, chemical mechanisms and the aerosol microphysical packages. Therefore, it is an ideal tool for assessing the effect of different parameters on aerosol indirect forcing. The aerosol module includes primary emissions, chemical production of sulfate in clear air and in-cloud aqueous phase, gravitational sedimentation, dry deposition, wet scavenging in and below clouds, and hygroscopic growth. Model inputs include SO2 (fossil fuel and natural), black carbon (BC), organic carbon (OC), mineral dust and sea salt. The meteorological data used in this work were taken from the NASA Data Assimilation Office (DAO) and two different GCMs: the NASA GEOS4 finite volume GCM (FVGCM) and the Goddard Institute for Space Studies version II' (GISS II') GCM. Simulations were carried out for "present day" and "preindustrial" emissions using different meteorological fields (i.e. DAO, FVGCM, GISS II'); cloud droplet number concentration is computed from the correlations of Boucher and Lohmann [1995], Abdul-Razzak and Ghan [2000], Feingold and Heymsfield [1992], Fountoukis and Nenes [2005] and Segal and Khain [2006]. Computed CDNC is used to calculate the cloud optical depth, the autoconversion rate and the mean top-of-the-atmosphere (TOA) short-wave radiative forcing using modified FAST-J algorithm [Meshkhidze et al., 2006]. Autoconversion of cloud water to precipitation is parameterized following the formulation of Khairoutdinov and Kogan [2000]. References Abdul-Razzak, H., and S. J. Ghan (2000), J. Geophys. Res., 105, 6837-6844. Boucher, O., and U. Lohmann (1995), Tellus, Ser. B, 47, 281- 300. Feingold, G. and A. Heymsfield (1992), J. Atmos. Sci., 49, 2325-2342. Fountoukis, C., and A. Nenes (2005), J. Geophys. Res., 110, D11212, doi:10.1029/ 2004JD005591. Intergovernmental Panel on Climate Change - IPCC (2001), Climate Change, The Scientific Basis, Cambridge University Press, UK. Khairoutdinov, M. and Y. Kogan (2000), Mon. Weather Rev., 128 (1), 229-243. Meshkhidze, N., A Nenes, J. Kouatchou, B. Das and J. Rodriguez, 7th International Aerosol Conference, American Association for Aerosol Research (IAC 2006), St. Paul, Minnesota, October 2006 Nenes, A., and J. H. Seinfeld (2003), J. Geophys. Res., 108, 4415, doi:10.1029/ 2002JD002911. Segal, Y., and A. Khain (2006), J. Geophys. Res., 111, D15204, doi:10.1029/2005JD006561.
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Divergent Effects of Dendritic Cells on Pancreatitis
2015-09-01
role of dendritic cells in pancreatitis. Dendritic cells are professional antigen presenting cells which initiate innate and adaptive immune... Lymphoid -tissue-specific homing of bone- marrow-derived dendritic cells . Blood. 113:6638–6647. http://dx.doi .org/10.1182/blood-2009-02-204321 Dapito...Award Number: W81XWH-12-1-0313 TITLE: Divergent Effects of Dendritic Cells on Pancreatitis PRINCIPAL INVESTIGATOR: Dr. George Miller
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A Photometric Analysis of ZZ Ceti Stars: A Parameter-Free Temperature Indicator?
2009-01-01
2MASS JHK measurements. 16th European White Dwarfs Workshop IOP Publishing Journal of Physics: Conference Series 172 (2009) 012062 doi:10.1088/1742-6596...172/1/012062 3 Table 1. Optical and infrared photometry of ZZ Ceti stars. UFTI 2MASS Name V R I J H K J H K Ross 548 14.16 14.37 14.36 14.40 14.38...Since the beginning of our survey, 2MASS photometry has also become available for 23 objects in our sample, and this data is reported in Table 1 and
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Penjweini, Rozhin; Kim, Michele M; Liu, Baochang; Zhu, Timothy C
2017-03-01
In the article by R. Penjweini, M. M. Kim et al. (doi: 10.1002/jbio.201600121), published in J. Biophotonics 9, 1344-1354 (2016), the constants C 01 , C 02 , b 1 , and b 2 determined from fitting the fluorescence single value decomposition (SVD) for phantoms with different optical properties and the corresponding Figure 2(a) are not correct. This erratum is published to correct the Section 2.3 and Figure 2(a). © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Neural circuitry coordinating male copulation
Pavlou, Hania J; Lin, Andrew C; Neville, Megan C; Nojima, Tetsuya; Diao, Fengqiu; Chen, Brian E; White, Benjamin H; Goodwin, Stephen F
2016-01-01
Copulation is the goal of the courtship process, crucial to reproductive success and evolutionary fitness. Identifying the circuitry underlying copulation is a necessary step towards understanding universal principles of circuit operation, and how circuit elements are recruited into the production of ordered action sequences. Here, we identify key sex-specific neurons that mediate copulation in Drosophila, and define a sexually dimorphic motor circuit in the male abdominal ganglion that mediates the action sequence of initiating and terminating copulation. This sexually dimorphic circuit composed of three neuronal classes – motor neurons, interneurons and mechanosensory neurons – controls the mechanics of copulation. By correlating the connectivity, function and activity of these neurons we have determined the logic for how this circuitry is coordinated to generate this male-specific behavior, and sets the stage for a circuit-level dissection of active sensing and modulation of copulatory behavior. DOI: http://dx.doi.org/10.7554/eLife.20713.001 PMID:27855059
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Phenotypic plasticity as an adaptation to a functional trade-off
Yi, Xiao; Dean, Antony M
2016-01-01
We report the evolution of a phenotypically plastic behavior that circumvents the hardwired trade-off that exists when resources are partitioned between growth and motility in Escherichia coli. We propagated cultures in a cyclical environment, alternating between growth up to carrying capacity and selection for chemotaxis. Initial adaptations boosted overall swimming speed at the expense of growth. The effect of the trade-off was subsequently eased through a change in behavior; while individual cells reduced motility during exponential growth, the faction of the population that was motile increased as the carrying capacity was approached. This plastic behavior was produced by a single amino acid replacement in FliA, a regulatory protein central to the chemotaxis network. Our results illustrate how phenotypic plasticity potentiates evolvability by opening up new regions of the adaptive landscape. DOI: http://dx.doi.org/10.7554/eLife.19307.001 PMID:27692064
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Archaeal TFEα/β is a hybrid of TFIIE and the RNA polymerase III subcomplex hRPC62/39
Blombach, Fabian; Salvadori, Enrico; Fouqueau, Thomas; Yan, Jun; Reimann, Julia; Sheppard, Carol; Smollett, Katherine L; Albers, Sonja V; Kay, Christopher WM; Thalassinos, Konstantinos; Werner, Finn
2015-01-01
Transcription initiation of archaeal RNA polymerase (RNAP) and eukaryotic RNAPII is assisted by conserved basal transcription factors. The eukaryotic transcription factor TFIIE consists of α and β subunits. Here we have identified and characterised the function of the TFIIEβ homologue in archaea that on the primary sequence level is related to the RNAPIII subunit hRPC39. Both archaeal TFEβ and hRPC39 harbour a cubane 4Fe-4S cluster, which is crucial for heterodimerization of TFEα/β and its engagement with the RNAP clamp. TFEα/β stabilises the preinitiation complex, enhances DNA melting, and stimulates abortive and productive transcription. These activities are strictly dependent on the β subunit and the promoter sequence. Our results suggest that archaeal TFEα/β is likely to represent the evolutionary ancestor of TFIIE-like factors in extant eukaryotes. DOI: http://dx.doi.org/10.7554/eLife.08378.001 PMID:26067235
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Abbott, Jennifer; Sandberg, Tami
The Wind-Wildlife Impacts Literature Database (WILD), formerly known as the Avian Literature Database, was created in 1997. The goal of the database was to begin tracking the research that detailed the potential impact of wind energy development on birds. The Avian Literature Database was originally housed on a proprietary platform called Livelink ECM from Open- Text and maintained by in-house technical staff. The initial set of records was added by library staff. A vital part of the newly launched Drupal-based WILD database is the Bibliography module. Many of the resources included in the database have digital object identifiers (DOI). Themore » bibliographic information for any item that has a DOI can be imported into the database using this module. This greatly reduces the amount of manual data entry required to add records to the database. The content available in WILD is international in scope, which can be easily discerned by looking at the tags available in the browse menu.« less
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Time-resolved analysis of nonlinear optical limiting for laser synthesized carbon nanoparticles
NASA Astrophysics Data System (ADS)
Chen, G. X.; Hong, M. H.
2010-11-01
Nonlinear optical limiting materials have attracted much research interest in recent years. Carbon nanoparticles suspended in liquids show a strong nonlinear optical limiting function. It is important to investigate the nonlinear optical limiting process of carbon nanoparticles for further improving their nonlinear optical limiting performance. In this study, carbon nanoparticles were prepared by laser ablation of a carbon target in tetrahydrofuran (THF). Optical limiting properties of the samples were studied with 532-nm laser light, which is in the most sensitive wavelength band for human eyes. The shape of the laser pulse plays an important role for initializing the nonlinear optical limiting effect. Time-resolved analysis of laser pulses discovered 3 fluence stages of optical limiting. Theoretical simulation indicates that the optical limiting is initialized by a near-field optical enhancement effect.
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Zhu, Ying; Soeriyadi, Alexander H; Parker, Stephen G; Reece, Peter J; Gooding, J Justin
2014-06-21
Porous silicon (PSi) rugate filters modified with alkyne-terminated monolayers were chemically patterned using a combination of photolithography of photoresist and click chemistry. Two chemical functionalities were obtained by conjugating, via click reactions, ethylene glycol moieties containing two different terminal groups to discrete areas towards the exterior of a PSi rugate filter. The patterning of biological species to the functionalized surface was demonstrated through the conjugation of fluorescein isothiocyanate labelled bovine serum albumin (FITC-BSA). Fluorescence microscopy showed selective positioning of FITC-BSA at discretely functionalized areas. Meanwhile, the optical information from precisely defined positions on the patterned surface was monitored by optical reflectivity measurements. The optical measurements revealed successful step-wise chemical functionalization followed by immobilization of gelatin. Multiplex detection of protease activity from different array elements on the patterned surface was demonstrated by monitoring the blue shifts in the reflectivity spectra resulted from the digestion of gelatin by subtilisin. Precise information from both individual elements and average population was acquired. This technique is important for the development of PSi into a microarray platform for highly parallel biosensing applications, especially for cell-based assays.
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Karan, Niladri S.; Keller, Aaron M.; Sampat, Siddharth; Roslyak, Oleksiy; Arefin, Ayesha; Hanson, Christina J.; Casson, Joanna L.; Desireddy, Anil; Ghosh, Yagnaseni; Piryatinski, Andrei; Iyer, Rashi; Htoon, Han; Malko, Anton V.
2015-01-01
Hybrid semiconductor–metal nanoscale constructs are of both fundamental and practical interest. Semiconductor nanocrystals are active emitters of photons when stimulated optically, while the interaction of light with nanosized metal objects results in scattering and ohmic damping due to absorption. In a combined structure, the properties of both components can be realized together. At the same time, metal–semiconductor coupling may intervene to modify absorption and/or emission processes taking place in the semiconductor, resulting in a range of effects from photoluminescence quenching to enhancement. We show here that photostable ‘giant’ quantum dots when placed at the center of an ultrathin gold shell retain their key optical property of bright and blinking-free photoluminescence, while the metal shell imparts efficient photothermal transduction. The latter is despite the highly compact total particle size (40–60 nm “inorganic” diameter and <100 nm hydrodynamic diameter) and the very thin nature of the optically transparent Au shell. Importantly, the sensitivity of the quantum dot emission to local temperature provides a novel internal thermometer for recording temperature during infrared irradiation-induced photothermal heating. PMID:29163879
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Debate on Global Warming as a Socio-Scientific Issue: Science Teaching towards Political Literacy
ERIC Educational Resources Information Center
Pereira dos Santos, Wildson Luiz
2014-01-01
The focus of this response to the original article by Tom G. H. Bryce and Stephen P. Day ("Cult Stud Sci Educ." doi:10.1007/s11422-012-9407-1, 2013) is the use of empirical data to illustrate and expand the understanding of key points of their argument. Initially, I seek to discuss possible answers to the three questions posed by the…
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Integrated Desert Terrain Forecasting for Military Operations
2013-02-15
N. Porat. The role of the Nile in initiating a massive dust influx to the Negev late in the middle Pleistocene, Geological Society of America... Negev , Israel, resulting from regional tectonics blocking Mediterranean frontal systems, Geology, (06 2006): 0. doi: 10.1130/G22354.1 12/16/2012...Finkel, N. Porat, Y. Enzel, Y. Eyal. Quaternary-scale evolution of sequences of talus ?atirons in the hyperarid Negev , Geomorphology, (12 2010): 0
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Huang, Wei; Placzek, Andon N; Viana Di Prisco, Gonzalo; Khatiwada, Sanjeev; Sidrauski, Carmela; Krnjević, Krešimir; Walter, Peter; Dani, John A; Costa-Mattioli, Mauro
2016-01-01
Adolescents are especially prone to drug addiction, but the underlying biological basis of their increased vulnerability remains unknown. We reveal that translational control by phosphorylation of the translation initiation factor eIF2α (p-eIF2α) accounts for adolescent hypersensitivity to cocaine. In adolescent (but not adult) mice, a low dose of cocaine reduced p-eIF2α in the ventral tegmental area (VTA), potentiated synaptic inputs to VTA dopaminergic neurons, and induced drug-reinforced behavior. Like adolescents, adult mice with reduced p-eIF2α-mediated translational control were more susceptible to cocaine-induced synaptic potentiation and behavior. Conversely, like adults, adolescent mice with increased p-eIF2α became more resistant to cocaine's effects. Accordingly, metabotropic glutamate receptor-mediated long-term depression (mGluR-LTD)—whose disruption is postulated to increase vulnerability to drug addiction—was impaired in both adolescent mice and adult mice with reduced p-eIF2α mediated translation. Thus, during addiction, cocaine hijacks translational control by p-eIF2α, initiating synaptic potentiation and addiction-related behaviors. These insights may hold promise for new treatments for addiction. DOI: http://dx.doi.org/10.7554/eLife.12052.001 PMID:26928234
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G-actin provides substrate-specificity to eukaryotic initiation factor 2α holophosphatases
Chen, Ruming; Rato, Cláudia; Yan, Yahui; Crespillo-Casado, Ana; Clarke, Hanna J; Harding, Heather P; Marciniak, Stefan J; Read, Randy J; Ron, David
2015-01-01
Dephosphorylation of eukaryotic translation initiation factor 2a (eIF2a) restores protein synthesis at the waning of stress responses and requires a PP1 catalytic subunit and a regulatory subunit, PPP1R15A/GADD34 or PPP1R15B/CReP. Surprisingly, PPP1R15-PP1 binary complexes reconstituted in vitro lacked substrate selectivity. However, selectivity was restored by crude cell lysate or purified G-actin, which joined PPP1R15-PP1 to form a stable ternary complex. In crystal structures of the non-selective PPP1R15B-PP1G complex, the functional core of PPP1R15 made multiple surface contacts with PP1G, but at a distance from the active site, whereas in the substrate-selective ternary complex, actin contributes to one face of a platform encompassing the active site. Computational docking of the N-terminal lobe of eIF2a at this platform placed phosphorylated serine 51 near the active site. Mutagenesis of predicted surface-contacting residues enfeebled dephosphorylation, suggesting that avidity for the substrate plays an important role in imparting specificity on the PPP1R15B-PP1G-actin ternary complex. DOI: http://dx.doi.org/10.7554/eLife.04871.001 PMID:25774600
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Zhang, Miao; Bommer, Martin; Chatterjee, Ruchira; Hussein, Rana; Yano, Junko; Dau, Holger; Kern, Jan; Dobbek, Holger; Zouni, Athina
2017-01-01
In plants, algae and cyanobacteria, Photosystem II (PSII) catalyzes the light-driven splitting of water at a protein-bound Mn4CaO5-cluster, the water-oxidizing complex (WOC). In the photosynthetic organisms, the light-driven formation of the WOC from dissolved metal ions is a key process because it is essential in both initial activation and continuous repair of PSII. Structural information is required for understanding of this chaperone-free metal-cluster assembly. For the first time, we obtained a structure of PSII from Thermosynechococcus elongatus without the Mn4CaO5-cluster. Surprisingly, cluster-removal leaves the positions of all coordinating amino acid residues and most nearby water molecules largely unaffected, resulting in a pre-organized ligand shell for kinetically competent and error-free photo-assembly of the Mn4CaO5-cluster. First experiments initiating (i) partial disassembly and (ii) partial re-assembly after complete depletion of the Mn4CaO5-cluster agree with a specific bi-manganese cluster, likely a di-µ-oxo bridged pair of Mn(III) ions, as an assembly intermediate. DOI: http://dx.doi.org/10.7554/eLife.26933.001 PMID:28718766
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The age and the probable parent body of the daytime arietid meteor shower
NASA Astrophysics Data System (ADS)
Abedin, Abedin; Wiegert, Paul; Pokorný, Petr; Brown, Peter
2017-01-01
The daytime Arietid meteor shower is active from mid-May to late June and is amongst the strongest of the annual meteor showers, comparable in activity and duration to the Perseids and the Geminids. Due to the daytime nature of the shower, the Arietids have mostly been constrained by radar studies. The Arietids exhibit a long-debated discrepancy in the semi-major axis and the eccentricity of meteoroid orbits as measured by radar and optical surveys. Radar studies yield systematically lower values for the semi-major axis and eccentricity, where the origin of these discrepancies remain unclear. The proposed parent bodies of the stream include comet 96P/Machholz [McIntosh, B.A., 1990. Comet P/Machholz and the Quadrantid meteor stream. Icarus 86, 894 299-304. doi:10.1016/0019-1035(90)90219-Y.] and more recently a member of the Marsden group of sun-skirting comets, P/1999 J6 [Sekanina, Z., Chodas, P.W., 2005. Origin of the Marsden and Kracht Groups of Sunskirting 922 Comets. I. Association with Comet 96P/Machholz and Its Interplanetary Complex. ApJS 923 161, 551-586. doi:10.1086/497374.]. In this work, we present detailed numerical modelling of the daytime Arietid meteoroid stream, with the goal to identifying the parent body and constraining the age of the stream. We use observational data from an extensive survey of the Arietids by the Canadian Meteor Orbit Radar (CMOR), in the period of 2002-2013, and several optical observations by the SonotaCo meteor network and the Cameras for All-sky Meteor Surveillance (CAMS). We find the most plausible scenario to be that the age and the formation mechanism of the Arietids is consistent with continuous cometary activity of 96P/Machholz over a time interval of ≈12,000 years. The sun-skirting comet P/1999 J6 suggested by [Sekanina, Z., Chodas, P.W., 2005. Origin of the Marsden and Kracht Groups of Sunskirting 922 Comets. I. Association with Comet 96P/Machholz and Its Interplanetary Complex. ApJS 923 161, 551-586. doi:10.1086/497374.] may contribute to the shower, but the comet break up prior to 950 CE they propose does not reproduce all the characteristics of the observed shower.
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Development, characterization, and validation of an optical transfer standard for ammonia in air
NASA Astrophysics Data System (ADS)
Lüttschwager, Nils; Balslev-Harder, David; Leuenberger, Daiana; Pogány, Andrea; Werhahn, Olav; Ebert, Volker
2017-04-01
Ammonia is an atmospheric trace gas that is predominantly emitted from anthropogenic agricultural activities. Since elevated levels of ammonia can have negative effects to human health as well as ecosystems, it is imperative to monitor and control ammonia emissions. This requires SI-traceable standards to calibrate ammonia monitoring instrumentation and to make measurements comparable. The lack of such standards became a pressing issue in recent years and the MetNH3 project (www.metnh3.eu) was initiated to fill the gap, pursuing different strategies. The work that we present was part of these endeavours and focusses on the development and application of an optical transfer standard for amount fraction measurements of ammonia in ambient air. An optical transfer standard (OTS) offers an alternative to calibrations of air monitoring instrumentation by means of reference gas mixtures. With an OTS, absolute amount fraction results are derived by evaluating absorption spectra using a spectral model and pre-measured spectral properties of the analyte. In that way, the instrument can measure calibration gas-independent ("calibration-free") and, moreover, can itself serve as standard to calibrate air monitoring analyzers. Molecular spectral properties are the excellent, non-drifting point of reference of the OTS and form, together with traceable measurements of temperature and pressure, the basis for SI-traceable amount fraction measurements. We developed an OTS based on a commercial cavity-ring-down spectrometer with a detection limit below 1 ppb (1 nmol/mol). A custom spectral data evaluation routine for absolute, calibration-free measurements, as well as measurements of spectral properties of ammonia with the focus on measurement uncertainty and traceability [1] are the fundaments of our OTS. Validation measurements were conducted using a SI-traceable ammonia reference gas generator over a period of several months. Here, we present an evaluation of the performance of our OTS from 1 ppb to 200 ppb. We found the results obtained with the OTS to be concordant to reference gas mixtures yielding amount fraction results with standard uncertainties of less than 3 %, for which an uncertainty budget is provided. Acknowledgement: This work was supported by the European Metrology Research Programme (EMRP). The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union. References 1. A. Pogány, O. Werhahn, and V. Ebert, High-Accuracy Ammonia Line Intensity Measurements at 1.5 µm, in Imaging and Applied Optics 2016, OSA Technical Digest (online) (Optical Society of America, 2016), paper JT3A.15, DOI: 10.1364/3D.2016.JT3A.15
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The National Eutrophication Survey: lake characteristics and historical nutrient concentrations
NASA Astrophysics Data System (ADS)
Stachelek, Joseph; Ford, Chanse; Kincaid, Dustin; King, Katelyn; Miller, Heather; Nagelkirk, Ryan
2018-01-01
Historical ecological surveys serve as a baseline and provide context for contemporary research, yet many of these records are not preserved in a way that ensures their long-term usability. The National Eutrophication Survey (NES) database is currently only available as scans of the original reports (PDF files) with no embedded character information. This limits its searchability, machine readability, and the ability of current and future scientists to systematically evaluate its contents. The NES data were collected by the US Environmental Protection Agency between 1972 and 1975 as part of an effort to investigate eutrophication in freshwater lakes and reservoirs. Although several studies have manually transcribed small portions of the database in support of specific studies, there have been no systematic attempts to transcribe and preserve the database in its entirety. Here we use a combination of automated optical character recognition and manual quality assurance procedures to make these data available for analysis. The performance of the optical character recognition protocol was found to be linked to variation in the quality (clarity) of the original documents. For each of the four archival scanned reports, our quality assurance protocol found an error rate between 5.9 and 17 %. The goal of our approach was to strike a balance between efficiency and data quality by combining entry of data by hand with digital transcription technologies. The finished database contains information on the physical characteristics, hydrology, and water quality of about 800 lakes in the contiguous US (Stachelek et al.(2017), https://doi.org/10.5063/F1639MVD). Ultimately, this database could be combined with more recent studies to generate meta-analyses of water quality trends and spatial variation across the continental US.
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Global stability of steady states in the classical Stefan problem for general boundary shapes
Hadžić, Mahir; Shkoller, Steve
2015-01-01
The classical one-phase Stefan problem (without surface tension) allows for a continuum of steady-state solutions, given by an arbitrary (but sufficiently smooth) domain together with zero temperature. We prove global-in-time stability of such steady states, assuming a sufficient degree of smoothness on the initial domain, but without any a priori restriction on the convexity properties of the initial shape. This is an extension of our previous result (Hadžić & Shkoller 2014 Commun. Pure Appl. Math. 68, 689–757 (doi:10.1002/cpa.21522)) in which we studied nearly spherical shapes. PMID:26261359
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Levine, Myron M; Pasetti, Marcela F
2016-07-01
In this issue of Clinical and Vaccine Immunology, Scobie and colleagues (H. M. Scobie et al., Clin Vaccine Immunol 23:546-554, 2016, http://dx.doi.org/10.1128/CVI.00052-16) report a nationwide serosurvey of tetanus immunity in >2,000 Cambodian women of child-bearing age to monitor progress toward maternal and neonatal tetanus elimination. This commentary discusses vaccines as interventions for disease control, elimination, and eradication and emphasizes the importance of the tools needed to monitor the effectiveness of initiatives that deliver the vaccines programmatically. Copyright © 2016, American Society for Microbiology. All Rights Reserved.
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A flood map based DOI decoding method for block detector: a GATE simulation study.
Shi, Han; Du, Dong; Su, Zhihong; Peng, Qiyu
2014-01-01
Positron Emission Tomography (PET) systems using detectors with Depth of Interaction (DOI) capabilities could achieve higher spatial resolution and better image quality than those without DOI. Up till now, most DOI methods developed are not cost-efficient for a whole body PET system. In this paper, we present a DOI decoding method based on flood map for low-cost conventional block detector with four-PMT readout. Using this method, the DOI information can be directly extracted from the DOI-related crystal spot deformation in the flood map. GATE simulations are then carried out to validate the method, confirming a DOI sorting accuracy of 85.27%. Therefore, we conclude that this method has the potential to be applied in conventional detectors to achieve a reasonable DOI measurement without dramatically increasing their complexity and cost of an entire PET system.
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Choice of crystal surface finishing for a dual-ended readout depth-of-interaction (DOI) detector.
Fan, Peng; Ma, Tianyu; Wei, Qingyang; Yao, Rutao; Liu, Yaqiang; Wang, Shi
2016-02-07
The objective of this study was to choose the crystal surface finishing for a dual-ended readout (DER) DOI detector. Through Monte Carlo simulations and experimental studies, we evaluated 4 crystal surface finishing options as combinations of crystal surface polishing (diffuse or specular) and reflector (diffuse or specular) options on a DER detector. We also tested one linear and one logarithm DOI calculation algorithm. The figures of merit used were DOI resolution, DOI positioning error, and energy resolution. Both the simulation and experimental results show that (1) choosing a diffuse type in either surface polishing or reflector would improve DOI resolution but degrade energy resolution; (2) crystal surface finishing with a diffuse polishing combined with a specular reflector appears a favorable candidate with a good balance of DOI and energy resolution; and (3) the linear and logarithm DOI calculation algorithms show overall comparable DOI error, and the linear algorithm was better for photon interactions near the ends of the crystal while the logarithm algorithm was better near the center. These results provide useful guidance in DER DOI detector design in choosing the crystal surface finishing and DOI calculation methods.
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Le, My-Tra; Kasprzak, Wojciech K; Kim, Taejin; Gao, Feng; Young, Megan YL; Yuan, Xuefeng; Shapiro, Bruce A; Seog, Joonil; Simon, Anne E
2017-01-01
Turnip crinkle virus contains a T-shaped, ribosome-binding, translation enhancer (TSS) in its 3’UTR that serves as a hub for interactions throughout the region. The viral RNA-dependent RNA polymerase (RdRp) causes the TSS/surrounding region to undergo a conformational shift postulated to inhibit translation. Using optical tweezers (OT) and steered molecular dynamic simulations (SMD), we found that the unusual stability of pseudoknotted element H4a/Ψ3 required five upstream adenylates, and H4a/Ψ3 was necessary for cooperative association of two other hairpins (H5/H4b) in Mg2+. SMD recapitulated the TSS unfolding order in the absence of Mg2+, showed dependence of the resistance to pulling on the 3D orientation and gave structural insights into the measured contour lengths of the TSS structure elements. Adenylate mutations eliminated one-site RdRp binding to the 3’UTR, suggesting that RdRp binding to the adenylates disrupts H4a/Ψ3, leading to loss of H5/H4b interaction and promoting a conformational switch interrupting translation and promoting replication. DOI: http://dx.doi.org/10.7554/eLife.22883.001 PMID:28186489
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A family of photoswitchable NMDA receptors
Berlin, Shai; Szobota, Stephanie; Reiner, Andreas; Carroll, Elizabeth C; Kienzler, Michael A; Guyon, Alice; Xiao, Tong; Trauner, Dirk; Isacoff, Ehud Y
2016-01-01
NMDA receptors, which regulate synaptic strength and are implicated in learning and memory, consist of several subtypes with distinct subunit compositions and functional properties. To enable spatiotemporally defined, rapid and reproducible manipulation of function of specific subtypes, we engineered a set of photoswitchable GluN subunits ('LiGluNs'). Photo-agonism of GluN2A or GluN2B elicits an excitatory drive to hippocampal neurons that can be shaped in time to mimic synaptic activation. Photo-agonism of GluN2A at single dendritic spines evokes spine-specific calcium elevation and expansion, the morphological correlate of LTP. Photo-antagonism of GluN2A alone, or in combination with photo-antagonism of GluN1a, reversibly blocks excitatory synaptic currents, prevents the induction of long-term potentiation and prevents spine expansion. In addition, photo-antagonism in vivo disrupts synaptic pruning of developing retino-tectal projections in larval zebrafish. By providing precise and rapidly reversible optical control of NMDA receptor subtypes, LiGluNs should help unravel the contribution of specific NMDA receptors to synaptic transmission, integration and plasticity. DOI: http://dx.doi.org/10.7554/eLife.12040.001 PMID:26929991
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NASA Astrophysics Data System (ADS)
Jun, LIU; Huang, Wei; Hongjie, Fan
2016-02-01
A novel method for finding the initial structure parameters of an optical system via the genetic algorithm (GA) is proposed in this research. Usually, optical designers start their designs from the commonly used structures from a patent database; however, it is time consuming to modify the patented structures to meet the specification. A high-performance design result largely depends on the choice of the starting point. Accordingly, it would be highly desirable to be able to calculate the initial structure parameters automatically. In this paper, a method that combines a genetic algorithm and aberration analysis is used to determine an appropriate initial structure of an optical system. We use a three-mirror system as an example to demonstrate the validity and reliability of this method. On-axis and off-axis telecentric three-mirror systems are obtained based on this method.
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Nonlinear optical waves with the second Painleve transcendent shape of envelope in Kerr media
NASA Astrophysics Data System (ADS)
Shcherbakov, Alexandre S.; Tepichin Rodriguez, Eduardo; Sanchez Sanchez, Mauro
2004-05-01
Nonlinear optical wave packets with the second Painleve transcendent shape of envelope are revealed in Kerr media, manifesting weakly focusing cubic nonlinearity, square-law dispersion, and linear losses. When the state of nonlinear optical transmission is realized, two possible types of boundary conditions turn out to be satisfied for these wave packets. The propagation of initially unchirped optical wave packets under consideration could be supported by lossless medium in both normal and anomalous dispersion regimes. At the same time initially chirped optical waves with the second Painleve transcendent shape in low-loss medium and need matching the magnitude of optical losses by the dispersion and nonlinear properties of that medium.
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Evolution of DOI Usage and Registration
NASA Astrophysics Data System (ADS)
James, N.; Wanchoo, L.
2017-12-01
NASA's Earth Science Data and Information System (ESDIS) Project has implemented an automated system for assigning Digital Object Identifiers (DOIs) to Earth Science data products being managed by its network of 12 distributed active archive centers (DAACs). Using the ESDIS DOI system, over 3000 DOIs have been assigned, registered, and made publicly accessible while over 1000 assigned DOIs are being held in reserve until ready for public use. The goal is to assign a DOI to each of the 8000+ data collections under ESDIS management. DOIs make it easier for researchers to discover and use earth science data and they enable users to provide valid citations for the data they use in research. Also for the researcher wishing to reproduce the results presented in science publications, the DOI can be used to locate the exact data or data products being cited. ESDIS DOIs also provide data "Provenance" which is information about the creation and history of the data in question. This would include when the data was collected, which instrument was used to collect the data, and the version of the product at the time the DOI was assigned. Over the past few years, requests for DOIs have increased significantly as DAACs assign DOIs to both legacy data from earlier missions and new data products from in-orbit missions. This study will evaluate the evolution of DOI registration and its usage over those years comparing data products as they are organized by mission, science discipline and data product level. It is hoped that the study results will help NASA determine how to prioritize future products for DOI assignment and inform future studies that would identify trends over time of increased use of data citations resulting in increased discovery and distribution of NASA Earth science data products.
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Open Access Data Centers as an Essential Partner to a Data Publication Journal
NASA Astrophysics Data System (ADS)
Carlson, D.; Pfeiffenberger, H.
2016-12-01
The success of Earth System Science Data derives in part from key infrastructure: digital object identifiers (doi) and open access data centers. Our concept that a data journal should promote access and exchange through publication of reviewed data descriptions presupposed third parties to hold the data. As minimum criteria for those data centers we expected international reputation for quality of service and an active lifetime extending at least a decade into the future. We also expected modern access interfaces offering geographic, topical and parameter-based browsing - so that users could discover related holdings through an ESSD link or discover ESSD by way of links in data sets revealed through the center's browse tools - and true open access. True open access means one or two clicks from abstract in ESSD to the data itself without barriers. We started with Pangaea and CDIAC. Data providers already used these centers, the staff welcomed the ESSD initiative and all parties cooperated on doi. With this initial support ESSD proved the basic concept of data publication and demonstrated utility to a larger group of data providers, many of whom suggested additional centers. So long as those data centers met expectations for open access and quality and durability of service, ESSD agreed to collaborate. Through back-door collaborations - e.g. service on particular data sets - ESSD developed working partnerships with more than 30 data centers in 13 countries. Data centers ask to join our list. We encourage those centers to stimulate local providers to submit a data set to ESSD, thus preserving our practical data-set by data-set partnership mode. For a few data centers where national policies impose a registration step, center staff and ESSD editors created bypass access routes to facilitate anonymous reviews. For ESSD purposes, open access and doi cooperation leading to reliable curation allows a win, win, win partnership among centers, providers, and journal.
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Evolution of the Specific Surface Area of Snow in a High Temperature Gradient Metamorphism
NASA Astrophysics Data System (ADS)
Wang, X.; Baker, I.
2014-12-01
The structural evolution of low-density snow under a high temperature gradient over a short period usually takes place in the surface layers during diurnal recrystallization or on a clear, cold night. To relate snow microstructures with their thermal properties, we combined X-ray computed microtomography (micro-CT) observations with numerical simulations. Different types of snow were tested over a large range of TGs (100 K m-1- 500 K m-1). The Specific Surface Area (SSA) was used to characterize the temperature gradient metamorphism (TGM). The magnitude of the temperature gradient and the initial snow type both influence the evolution of SSA. The SSA evolution under TGM was dominated by grain growth and the formation of complex surfaces. Fresh snow experienced a logarithmic decrease of SSA with time, a feature been observed previously by others [Calonne et al., 2014; Schneebeli and Sokratov, 2004; Taillandier et al., 2007]. However, for initial rounded and connected snow structures, the SSA will increase during TGM. Understanding the SSA increase is important in order to predict the enhanced uptake of chemical species by snow or increase in snow albedo. Calonne, N., F. Flin, C. Geindreau, B. Lesaffre, and S. Rolland du Roscoat (2014), Study of a temperature gradient metamorphism of snow from 3-D images: time evolution of microstructures, physical properties and their associated anisotropy, The Cryosphere Discussions, 8, 1407-1451, doi:10.5194/tcd-8-1407-2014. Schneebeli, M., and S. A. Sokratov (2004), Tomography of temperature gradient metamorphism of snow and associated changes in heat conductivity, Hydrological Processes, 18(18), 3655-3665, doi:10.1002/hyp.5800. Taillandier, A. S., F. Domine, W. R. Simpson, M. Sturm, and T. A. Douglas (2007), Rate of decrease of the specific surface area of dry snow: Isothermal and temperature gradient conditions, Journal of Geophysical Research: Earth Surface (2003-2012), 112(F3), doi: 10.1029/2006JF000514.
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Long-term vegetation monitoring in Great Britain - the Countryside Survey 1978-2007 and beyond
NASA Astrophysics Data System (ADS)
Wood, Claire M.; Smart, Simon M.; Bunce, Robert G. H.; Norton, Lisa R.; Maskell, Lindsay C.; Howard, David C.; Scott, W. Andrew; Henrys, Peter A.
2017-07-01
The Countryside Survey (CS) of Great Britain provides a globally unique series of datasets, consisting of an extensive set of repeated ecological measurements at a national scale, covering a time span of 29 years. CS was first undertaken in 1978 to monitor ecological and land use change in Britain using standardised procedures for recording ecological data from representative 1 km squares throughout the country. The same sites, with some additional squares, were used for subsequent surveys of vegetation undertaken in 1990, 1998 and 2007, with the intention of future surveys. Other data records include soils, freshwater habitats and invertebrates, and land cover and landscape feature diversity and extents. These data have been recorded in the same locations on analogous dates. However, the present paper describes only the details of the vegetation surveys. The survey design is a series of gridded, stratified, randomly selected 1 km squares taken as representative of classes derived from a statistical environmental classification of Britain. In the 1978 survey, 256 one-kilometre sample squares were recorded, increasing to 506 in 1990, 569 in 1998 and 591 in 2007. Initially each square contained up to 11 dispersed vegetation plots but additional plots were later placed in different features so that eventually up to 36 additional sampling plots were recorded, all of which can be relocated where possible (unless the plot has been lost, for example as a consequence of building work), providing a total of 16 992 plots by 2007. Plots are estimated to have a precise relocation accuracy of 85 %. A range of plots located in different land cover types and landscape features (for example, field boundaries) are included. Although a range of analyses have already been carried out, with changes in the vegetation being related to a range of drivers at local and national scales, there is major potential for further analyses, for example in relation to climate change. Although the precise locations of the plots are restricted, largely for reasons of landowner confidentiality, sample sites are intended to be representative of larger areas, and many potential opportunities for further analyses remain. Data from each of the survey years (1978, 1990, 1998, 2007) are available via the following DOIs: Countryside Survey 1978 vegetation plot data (https://doi.org/10.5285/67bbfabb-d981-4ced-b7e7-225205de9c96), Countryside Survey 1990 vegetation plot data (https://doi.org/10.5285/26e79792-5ffc-4116-9ac7-72193dd7f191), Countryside Survey 1998 vegetation plot data (https://doi.org/10.5285/07896bb2-7078-468c-b56d-fb8b41d47065), Countryside Survey 2007 vegetation plot data (https://doi.org/10.5285/57f97915-8ff1-473b-8c77-2564cbd747bc).
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Modular initiator with integrated optical diagnostic
Alam, M Kathleen [Cedar Crest, NM; Schmitt, Randal L [Tijeras, NM; Welle, Eric J [Niceville, FL; Madden, Sean P [Arlington, MA
2011-05-17
A slapper detonator which integrally incorporates an optical wavequide structure for determining whether there has been degradation of the explosive in the explosive device that is to be initiated by the detonator. Embodiments of this invention take advantage of the barrel-like character of a typical slapper detonator design. The barrel assembly, being in direct contact with the energetic material, incorporates an optical diagnostic device into the barrel assembly whereby one can monitor the state of the explosive material. Such monitoring can be beneficial because the chemical degradation of the explosive plays an important in achieving proper functioning of a detonator/initiator device.
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One-Year Observations of Jupiter by the Jovian Infrared Auroral Mapper on Juno
NASA Astrophysics Data System (ADS)
Adriani, A.; Mura, A.; Bolton, S. J.; Connerney, J. E. P.; Levin, S.; Becker, H. N.; Bagenal, F.; Hansen, C. J.; Orton, G.; Gladstone, R.; Kurth, W. S.; Mauk, B.; Valek, P. W.
2017-12-01
The Jovian InfraRed Auroral Mapper (JIRAM) [1] on board the Juno [2,3] spacecraft, is equipped with an infrared camera and a spectrometer working in the spectral range 2-5 μm. JIRAM was built to study the infrared aurora of Jupiter as well as to map the planet's atmosphere in the 5 µm spectral region. The spectroscopic observations are used for studying clouds and measuring the abundance of some chemical species that have importance in the atmosphere's chemistry, microphysics and dynamics like water, ammonia and phosphine. During 2017 the instrument will operate during all 7 of Juno's Jupiter flybys. JIRAM has performed several observations of the polar regions of the planet addressing the aurora and the atmosphere. Unprecedented views of the aurora and the polar atmospheric structures have been obtained. We present a survey of the most significant observations that the instrument has performed during the current year. [1] Adriani A. et al., JIRAM, the Jovian Infrared Auroral Mapper. Space Sci. Rew., DOI 10.1007/s11214-014-0094-y, 2014. [2] Bolton S.J. et al., Jupiter's interior and deep atmosphere: The initial pole-to-pole passes with the Juno spacecraft. Science DOI: 10.1126/science.aal2108, 2017. [3] Connerney J. E.P. et al., Jupiter's magnetosphere and aurorae observed by the Juno spacecraft during its first polar orbits. Science, DOI: 10.1126/science.aam5928, 2017.
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Ara, Satoshi; Yamazaki, Harutake; Takaku, Hiroaki
2018-04-01
2-Deoxy-scyllo-inosose (DOI) is the first intermediate in the 2-deoxystreptamine-containing aminoglycoside antibiotic biosynthesis pathway and has a six-membered carbocycle structure. DOI is a valuable material because it is easily converted to aromatic compounds and carbasugar derivatives. In this study, we isolated yeast strains capable of assimilating DOI as a carbon source. One of the strains, Cryptococcus podzolicus ND1, mainly converted DOI to scyllo-quercitol and (-)-vibo-quercitol, which is a valuable compound used as an antihypoglycemia agent and as a heat storage material. An NADH-dependent DOI reductase coding gene, DOIR, from C. podzolicus ND1 was cloned and successfully overexpressed in Escherichia coli. The purified protein catalyzed the irreversible reduction of DOI with NADH and converted DOI into (-)-vibo-quercitol. The enzyme had an optimal pH of 8.5 and optimal temperature of 35°C, respectively. The k cat of this enzyme was 9.98 s -1 , and the K m values for DOI and NADH were 4.38 and 0.24 mM, respectively. The enzyme showed a strong preference for NADH and showed no activity with NADPH. Multiple-alignment analysis of DOI reductase revealed that it belongs to the GFO_IDH_MocA protein family and is an inositol dehydrogenase homolog in other fungi, such as Cryptococcus gattii, and bacteria, such as Bacillus subtilis. This is the first identification of a DOI-assimilating yeast and a gene involved in DOI metabolism in fungi. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.
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Giant elves: Lightning-generated electromagnetic pulses in giant planets.
NASA Astrophysics Data System (ADS)
Luque Estepa, Alejandro; Dubrovin, Daria; José Gordillo-Vázquez, Francisco; Ebert, Ute; Parra-Rojas, Francisco Carlos; Yair, Yoav; Price, Colin
2015-04-01
We currently have direct optical observations of atmospheric electricity in the two giant gaseous planets of our Solar System [1-5] as well as radio signatures that are possibly generated by lightning from the two icy planets Uranus and Neptune [6,7]. On Earth, the electrical activity of the troposphere is associated with secondary electrical phenomena called Transient Luminous Events (TLEs) that occur in the mesosphere and lower ionosphere. This led some researchers to ask if similar processes may also exist in other planets, focusing first on the quasi-static coupling mechanism [8], which on Earth is responsible for halos and sprites and then including also the induction field, which is negligible in our planet but dominant in Saturn [9]. However, one can show that, according to the best available estimation for lightning parameters, in giant planets such as Saturn and Jupiter the effect of the electromagnetic pulse (EMP) dominates the effect that a lightning discharge has on the lower ionosphere above it. Using a Finite-Differences, Time-Domain (FDTD) solver for the EMP we found [10] that electrically active storms may create a localized but long-lasting layer of enhanced ionization of up to 103 cm-3 free electrons below the ionosphere, thus extending the ionosphere downward. We also estimate that the electromagnetic pulse transports 107 J to 1010 J toward the ionosphere. There emissions of light of up to 108 J would create a transient luminous event analogous to a terrestrial elve. Although these emissions are about 10 times fainter than the emissions coming from the lightning itself, it may be possible to target them for detection by filtering the appropiate wavelengths. [1] Cook, A. F., II, T. C. Duxbury, and G. E. Hunt (1979), First results on Jovian lightning, Nature, 280, 794, doi:10.1038/280794a0. [2] Little, B., C. D. Anger, A. P. Ingersoll, A. R. Vasavada, D. A. Senske, H. H. Breneman, W. J. Borucki, and The Galileo SSI Team (1999), Galileo images of lightning on Jupiter, Icarus, 142, 306-323, doi:10.1006/icar.1999.6195. [3] Dyudina, U. A., A. D. Del Genio, A. P. Ingersoll, C. C. Porco, R. A. West, A. R. Vasavada, and J. M. Barbara (2004), Lightning on Jupiter observed in the Hα line by the Cassini imaging science subsystem, Icarus, 172, 24-36, doi:10.1016/j.icarus.2004.07.014. [4] Baines, K. H., et al. (2007), Polar lightning and decadal-scale cloud variability on Jupiter, Science, 318, 226-229, doi:10.1126/science.1147912. [5] Dyudina, U. A., A. P. Ingersoll, S. P. Ewald, C. C. Porco, G. Fischer, W. S. Kurth, and R. A. West (2010), Detection of visible lightning on Saturn, Geophys. Res. Lett., 37, L09205, doi:10.1029/2010GL043188. [6] Zarka, P., and B. M. Pedersen (1986), Radio detection of Uranian lightning by Voyager 2, Nature, 323, 605-608, doi:10.1038/323605a0. [7] Gurnett, D. A., W. S. Kurth, I. H. Cairns, and L. J. Granroth (1990), Whistlers in Neptune's magnetosphere'Evidence of atmospheric lightning, J. Geophys. Res., 95, 20,967-20,976, doi:10.1029/JA095iA12p20967. [8] Yair, Y., Y. Takahashi, R. Yaniv, U. Ebert, and Y. Goto (2009), A study of the possibility of sprites in the atmospheres of other planets, J. Geophys. Res., 114, E09002, doi:10.1029/2008JE003311. [9] Dubrovin, D., A. Luque, F. J. Gordillo-Vázquez, Y. Yair, F. C. Parra-Rojas, U. Ebert, and C. Price (2014), Impact of lightning on the lower ionosphere of Saturn and possible generation of halos and sprites, Icarus, 241, 313-328, doi:10.1016/j.icarus.2014.06.025. [10] Luque, A., D. Dubrovin, F. J. Gordillo-Vázquez, U. Ebert, F. C. Parra-Rojas, Y. Yair, and C. Price (2014), Coupling between atmospheric layers in gaseous giant planets due to lightning-generated electromagnetic pulses, J. Geophys. Res. Space Physics, 119, doi:10.1002/2014JA020457.
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The Africa Initiative for Planetary and Space Sciences
NASA Astrophysics Data System (ADS)
Baratoux, D.; Chennaoui-Aoudjehane, H.; Gibson, R.; Lamali, A.; Reimold, W. U.; Selorm Sepah, M.; Chabou, M. C.; Habarulema, J. B.; Jessell, M.; Mogessie, A.; Benkhaldoun, Z.; Nkhonjera, E.; Mukosi, N. C.; Kaire, M.; Rochette, P.; Sickafoose, A.; Martínez-Frías, J.; Hofmann, A.; Folco, L.; Rossi, A. P.; Faye, G.; Kolenberg, K.; Tekle, K.; Belhai, D.; Elyajouri, M.; Koeberl, C.; Abdeem, M.
2017-12-01
Research groups in Planetary and Space Sciences (PSS) are now emerging in Africa, but remain few, scattered and underfunded. It is our conviction that the exclusion of 20% of the world's population from taking part in the fascinating discoveries about our solar system impoverishes global science. The benefits of a coordinated PSS program for Africa's youth have motivated a call for international support and investment [1] into an Africa Initiative for Planetary and Space Sciences. At the time of writing, the call has been endorsed by 230 scientists and 19 institutions or international organizations (follow the map of endorsements on https://africapss.org). More than 70 African Planetary scientists have already joined the initiative and about 150 researchers in non-African countries are ready to participate in research and in capacitity building of PSS programs in Africa. We will briefly review in this presentation the status of PSS in Africa [2] and illustrate some of the major achievements of African Planetary and Space scientists, including the search for meteorites or impact craters, the observations of exoplanets, and space weather investigations. We will then discuss a road map for its expansion, with an emphasis on the role that planetary and space scientists can play to support scientific and economic development in Africa. The initiative is conceived as a network of projects with Principal Investigators based in Africa. A Steering Committee is being constituted to coordinate these efforts and contribute to fund-raising and identification of potential private and public sponsors. The scientific strategy of each group within the network will be developed in cooperation with international experts, taking into account the local expertise, available equipment and facilities, and the priority needs to achieve well-identified scientific goals. Several founding events will be organized in 2018 in several African research centers and higher-education institutions to initiate this process. References: [1] Baratoux, D., et al. (2017) Africa initiative for planetary and space sciences, Eos, 98, https://doi.org/10.1029/2017EO075935. [2] Baratoux, D., et al. (2017) The state of planetary and space sciences in Africa, Eos, 98, https://doi.org/10.1029/2017EO075833.
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Beam shaping for laser initiated optical primers
NASA Astrophysics Data System (ADS)
Lizotte, Todd E.
2008-08-01
Remington was one of the first firearm manufacturing companies to file a patent for laser initiated firearms, in 1969. Nearly 40 years later, the development of laser initiated firearms has not become a mainstream technology in the civilian market. Requiring a battery is definitely a short coming, so it is easy to see how such a concept would be problematic. Having a firearm operate reliably and the delivery of laser energy in an efficient manner to ignite the shock-sensitive explosive primer mixtures is a tall task indeed. There has been considerable research on optical element based methods of transferring or compressing laser energy to ignite primer charges, including windows, laser chip primers and various lens shaped windows to focus the laser energy. The focusing of laser light needs to achieve igniting temperatures upwards of >400°C. Many of the patent filings covering this type of technology discuss simple approaches where a single point of light might be sufficient to perform this task. Alternatively a multi-point method might provide better performance, especially for mission critical applications, such as precision military firearms. This paper covers initial design and performance test of the laser beam shaping optics to create simultaneous multiple point ignition locations and a circumferential intense ring for igniting primer charge compounds. A simple initial test of the ring beam shaping technique was evaluated on a standard large caliber primer to determine its effectiveness on igniting the primer material. Several tests were conducted to gauge the feasibility of laser beam shaping, including optic fabrication and mounting on a cartridge, optic durability and functional ignition performance. Initial data will be presented, including testing of optically elements and empirical primer ignition / burn analysis.
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Alignment of the Korsch type off-axis 3 mirror optical system using sensitivity table method
NASA Astrophysics Data System (ADS)
Lee, Kyoungmuk; Kim, Youngsoo; Hong, Jinsuk; Kim, Sug-Whan; Lee, Haeng-Bok; Choi, Se-Chol
2018-05-01
The optical system of the entire mechanical and optical components consist of all silicon carbide (SiC) is designed, manufactured and aligned. The Korsch type Cassegrain optical system has 3-mirrors, the primary mirror (M1), the secondary mirror (M2), the folding mirror (FM) and the tertiary mirror (M3). To assemble the M3 and the FM to the rear side of the M1 bench, the optical axis of the M3 is 65.56 mm off from the physical center. Due to the limitation of the mass budget, the M3 is truncated excluding its optical axis. The M2 was assigned to the coma compensator and the M3 the astigmatism respectively as per the result of the sensitivity analysis. Despite of the difficulty of placing these optical components in their initial position within the mechanical tolerance, the initial wave front error (WFE) performance is as large as 171.4 nm RMS. After the initial alignment, the sensitivity table method is used to reach the goal of WFE 63.3 nm RMS in all fields. We finished the alignment with the final WFE performance in all fields are as large as 55.18 nm RMS.
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Adaptive optics self-calibration using differential OTF (dOTF)
NASA Astrophysics Data System (ADS)
Rodack, Alexander T.; Knight, Justin M.; Codona, Johanan L.; Miller, Kelsey L.; Guyon, Olivier
2015-09-01
We demonstrate self-calibration of an adaptive optical system using differential OTF [Codona, JL; Opt. Eng. 0001; 52(9):097105-097105. doi:10.1117/1.OE.52.9.097105]. We use a deformable mirror (DM) along with science camera focal plane images to implement a closed-loop servo that both flattens the DM and corrects for non-common-path aberrations within the telescope. The pupil field modification required for dOTF measurement is introduced by displacing actuators near the edge of the illuminated pupil. Simulations were used to develop methods to retrieve the phase from the complex amplitude dOTF measurements for both segmented and continuous sheet MEMS DMs and tests were performed using a Boston Micromachines continuous sheet DM for verification. We compute the actuator correction updates directly from the phase of the dOTF measurements, reading out displacements and/or slopes at segment and actuator positions. Through simulation, we also explore the effectiveness of these techniques for a variety of photons collected in each dOTF exposure pair.
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First principles electron-correlated calculations of optical absorption in magnesium clusters★
NASA Astrophysics Data System (ADS)
Shinde, Ravindra; Shukla, Alok
2017-11-01
In this paper, we report large-scale configuration interaction (CI) calculations of linear optical absorption spectra of various isomers of magnesium clusters Mgn (n = 2-5), corresponding to valence transitions. Geometry optimization of several low-lying isomers of each cluster was carried out using coupled-cluster singles doubles (CCSD) approach, and these geometries were subsequently employed to perform ground and excited state calculations using either the full-CI (FCI) or the multi-reference singles-doubles configuration interaction (MRSDCI) approach, within the frozen-core approximation. Our calculated photoabsorption spectrum of magnesium dimer (Mg2) is in excellent agreement with the experiments both for peak positions, and intensities. Owing to the sufficiently inclusive electron-correlation effects, these results can serve as benchmarks against which future experiments, as well as calculations performed using other theoretical approaches, can be tested. Supplementary material in the form of one pdf fille available from the Journal web page at http://https://doi.org/10.1140/epjd/e2017-80356-6.
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A multi-approach to the optical depth of a contrail cirrus cluster
NASA Astrophysics Data System (ADS)
Vazquez-Navarro, Margarita; Bugliaro, Luca; Schumann, Ulrich; Strandgren, Johan; Wirth, Martin; Voigt, Christiane
2017-04-01
Amongst the individual aviation emissions, contrail cirrus contribute the largest fraction to the aviation effects on climate. To investigate the optical depth from contrail cirrus, we selected a cirrus and contrail cloud outbreak on the 10th April 2014 between the North Sea and Switzerland detected during the ML-CIRRUS experiment (Voigt et al., 2017). The outbreak was not forecast by weather prediction models. We describe its origin and evolution using a combination of in-situ measurements, remote sensing approaches and contrail prediction model prognosis. The in-situ and lidar measurements were carried out with the HALO aircraft, where the cirrus was first identified. Model predictions from the contrail prediction model CoCiP (Schumann et al., 2012) point to an anthropogenic origin. The satellite pictures from the SEVIRI imager on MSG combined with the use of a contrail cluster tracking algorithm enable the automatic assessment of the origin, displacement and growth of the cloud and the correct labeling of cluster pixels. The evolution of the optical depth and particle size of the selected cluster pixels were derived using the CiPS algorithm, a neural network primarily based on SEVIRI images. The CoCiP forecast of the cluster compared to the actual cluster tracking show that the model correctly predicts the occurrence of the cluster and its advection direction although the cluster spreads faster than simulated. The optical depth derived from CiPS and from the airborne high spectral resolution lidar WALES are compared and show a remarkably good agreement. This confirms that the new CiPS algorithm is a very powerful tool for the assessment of the optical depth of even optically thinner cirrus clouds. References: Schumann, U.: A contrail cirrus prediction model, Geosci. Model Dev., 5, 543-580, doi: 10.5194/gmd-5-543-2012, 2012. Voigt, C., Schumann, U., Minikin, A., Abdelmonem, A., Afchine, A., Borrmann, S., Boettcher, M., Buchholz, B., Bugliaro, L., Costa, A., Curtius, J., Dollner, M., Dörnbrack, A., Dreiling, V., Ebert, V., Ehrlich, A., Fix, A., Forster, L., Frank, F., Fütterer, D., Giez, A., Graf, K., Grooß, J.-U., Groß, S., Heimerl, K., Heinold, B., Hüneke, T., Järvinen, E., Jurkat, T., Kaufmann, S., Kenntner, M., Klingebiel, M., Klimach, T., Kohl, R., Krämer, M., Krisna, T. C., Luebke, A., Mayer, B., Mertes, S., Molleker, S., Petzold, A., Pfeilsticker, K., Port, M., Rapp, M., Reutter, P., Rolf, C., Rose, D., Sauer, D., Schäfler, A., Schlage, R., Schnaiter, M., Schneider, J., Spelten, N., Spichtinger, P., Stock, P., Walser, A., Weigel, R., Weinzierl, B., Wendisch, M., Werner, F., Wernli, H., Wirth, M., Zahn, A., Ziereis, H., and Zöger, M.: ML-CIRRUS - The airborne experiment on natural cirrus and contrail cirrus with the high-altitude long-range research aircraft HALO, Bull. Amer. Meteorol. Soc., in press, doi: 10.1175/BAMS-D-15-00213.1, 2017.
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2015-04-01
In issue 21.1 three of the DOIs were printed incorrectly, please see below for the correct information. Andrea Giorgianni, et al. Flow-diverter stenting of post-traumatic bilateral anterior cerebral artery pseudoaneurysm: A case report. Doi: 10.15274/INR-2014-10059 Correct: Doi: 10.1177/1591019915575441 Lee-Anne Slater, et al. Effect of flow diversion with silk on aneurysm size: A single center experience. Doi: 10.15274/INR-2014-10062 Correct DOI: 10.1177/1591019915576433 Robert J McDonald, et al. Periprocedural safety of Pipeline therapy for unruptured cerebral aneurysms: Analysis of 279 Patients in a multihospital database. Doi: 10.15274/INR-2014-10074 Correct DOI: 10.1177/1591019915576289. © The Author(s) 2015 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.
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NASA Astrophysics Data System (ADS)
Hoff, R. M.
2014-12-01
In 2009, the Air and Waste Management Association invited their annual critical review on the topic of measurement of surface particulate air pollution from satellites (Hoff and Christopher, 2009). At that time, over thirty publications had addressed the relationship between aerosol optical depth measured from satellites and the emissions, transport, and exposure at the surface from man-made haze, dust, and smoke. I will revisit the conclusions reached in that critical review, which we subtitled "Have we reached the promised land". Five years later and dozens of subsequent publications later on this topic, have we really advanced the state of the science in relating optical properties to surface measurements or are we just generating more data? The VIIRS imager and the upcoming GOES-R imager have the potential to provide higher spatial and temporal observations of aerosol optical depth from space. But to address the need for quantitatively improving estimates of exposure at the surface, is this enough or do we need to combine observing systems to address the real physics of the problem? Hoff, R. M. and S. A. Christopher, 2009. The 34th AWMA Critical Review: Remote Sensing of Particulate Pollution from Space: Have We Reached the Promised Land? J. Air & Waste Manage. Assoc. 59, 645-675, DOI:10.3155/1047-3289.59.6.645.
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Khalid, Muhammad Waqas; Ahmed, Rajib; Yetisen, Ali K.
2018-01-01
Optical sensors for detecting temperature and strain play a crucial role in the analysis of environmental conditions and real-time remote sensing. However, the development of a single optical device that can sense temperature and strain simultaneously remains a challenge. Here, a flexible corner cube retroreflector (CCR) array based on passive dual optical sensing (temperature and strain) is demonstrated. A mechanical embossing process was utilised to replicate a three-dimensional (3D) CCR array in a soft flexible polymer film. The fabricated flexible CCR array samples were experimentally characterised through reflection measurements followed by computational modelling. As fabricated samples were illuminated with a monochromatic laser beam (635, 532, and 450 nm), a triangular shape reflection was obtained at the far-field. The fabricated flexible CCR array samples tuned retroreflected light based on external stimuli (temperature and strain as an applied force). For strain and temperature sensing, an applied force and temperature, in the form of weight suspension, and heat flow was applied to alter the replicated CCR surface structure, which in turn changed its optical response. Directional reflection from the heated flexible CCR array surface was also measured with tilt angle variation (max. up to 10°). Soft polymer CCRs may have potential in remote sensing applications, including measuring the temperature in space and in nuclear power stations. PMID:29568510
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Tsunami mitigation - redistribution of energy
NASA Astrophysics Data System (ADS)
Kadri, Usama
2017-04-01
Tsunamis are water waves caused by the displacement of a large volume of water, in the deep ocean or a large lake, following an earthquake, landslide, underwater explosion, meteorite impacts, or other violent geological events. On the coastline, the resulting waves evolve from unnoticeable to devastating, reaching heights of tens of meters and causing destruction of property and loss of life. Over 225,000 people were killed in the 2004 Indian Ocean tsunami alone. For many decades, scientists have been studying tsunami, and progress has been widely reported in connection with the causes (1), forecasting (2), and recovery (3). However, none of the studies ratifies the approach of a direct mitigation of tsunamis, with the exception of mitigation using submarine barriers (e.g. see Ref. (4)). In an attempt to open a discussion on direct mitigation, I examine the feasibility of redistributing the total energy of a very long surface ocean (gravity) wave over a larger space through nonlinear resonant interaction with two finely tuned acoustic-gravity waves (see Refs. (5-8)). Theoretically, while the energy input in the acoustic-gravity waves required for an effective interaction is comparable to that in a tsunami (i.e. impractically large), employing the proposed mitigation technique the initial tsunami amplitude could be reduced substantially resulting in a much milder impact at the coastline. Moreover, such a technique would allow for the harnessing of the tsunami's own energy. Practically, this mitigation technique requires the design of highly accurate acoustic-gravity wave frequency transmitters or modulators, which is a rather challenging ongoing engineering problem. References 1. E. Bryant, 2014. Tsunami: the underrated hazard. Springer, doi:10.1007/978-3-319- 06133-7. 2. V. V. Titov, F. I. Gonza`lez, E. N. Bernard, M. C. Eble, H. O. Mofjeld, J. C. Newman, A. J. Venturato, 2005. Real-Time Tsunami Forecasting: Challenges and Solutions. Nat. Hazards 35:41-58, doi:10.1007/1-4020-3607-8 3 3. E. Check, 2005. Natural disasters: Roots of recovery. Nature 438, 910-911, doi:10.1038/438910a. 4. A. M. Fridman, L. S. Alperovich, L. Shemer, L. Pustil'nik, D. Shtivelman, A. G. Marchuk, D. Liberzon, 2010. Tsunami wave suppression using submarine barriers. Phys. Usp. 53 809-816, doi:10.3367/UFNe.0180.201008d.0843. 5. U. Kadri, M. Stiassnie, 2013. Generation of an acoustic-gravity wave by two gravity waves, and their mutual interaction. J. Fluid Mech. 735, R6, doi:10.1017/jfm.2013.539. 6. U. Kadri, 2015. Wave motion in a heavy compressible fluid: revisited. European Journal of Mechanics - B/Fluids, 49(A), 50-57, doi:10.1016/j.euromechflu.2014.07.008 7. U. Kadri, T.R. Akylas, 2016. On resonant triad interactions of acoustic-gravity waves. J. Fluid Mech., 788, R1(12 pages), doi:10.1017/jfm.2015.721. 8. U. Kadri, 2016. Triad resonance between a surface-gravity wave and two high frequency hydro-acoustic waves. Eur. J. Mech. B/Fluid, 55(1), 157-161, doi:10.1016/j.euromechflu.2015.09.008.
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Lessons from Fraxinus, a crowd-sourced citizen science game in genomics
Rallapalli, Ghanasyam; Saunders, Diane GO; Yoshida, Kentaro; Edwards, Anne; Lugo, Carlos A; Collin, Steve; Clavijo, Bernardo; Corpas, Manuel; Swarbreck, David; Clark, Matthew; Downie, J Allan; Kamoun, Sophien
2015-01-01
In 2013, in response to an epidemic of ash dieback disease in England the previous year, we launched a Facebook-based game called Fraxinus to enable non-scientists to contribute to genomics studies of the pathogen that causes the disease and the ash trees that are devastated by it. Over a period of 51 weeks players were able to match computational alignments of genetic sequences in 78% of cases, and to improve them in 15% of cases. We also found that most players were only transiently interested in the game, and that the majority of the work done was performed by a small group of dedicated players. Based on our experiences we have built a linear model for the length of time that contributors are likely to donate to a crowd-sourced citizen science project. This model could serve a guide for the design and implementation of future crowd-sourced citizen science initiatives. DOI: http://dx.doi.org/10.7554/eLife.07460.001 PMID:26219214
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Distributed task-specific processing of somatosensory feedback for voluntary motor control
Omrani, Mohsen; Murnaghan, Chantelle D; Pruszynski, J Andrew; Scott, Stephen H
2016-01-01
Corrective responses to limb disturbances are surprisingly complex, but the neural basis of these goal-directed responses is poorly understood. Here we show that somatosensory feedback is transmitted to many sensory and motor cortical regions within 25 ms of a mechanical disturbance applied to the monkey’s arm. When limb feedback was salient to an ongoing motor action (task engagement), neurons in parietal area 5 immediately (~25 ms) increased their response to limb disturbances, whereas neurons in other regions did not alter their response until 15 to 40 ms later. In contrast, initiation of a motor action elicited by a limb disturbance (target selection) altered neural responses in primary motor cortex ~65 ms after the limb disturbance, and then in dorsal premotor cortex, with no effect in parietal regions until 150 ms post-perturbation. Our findings highlight broad parietofrontal circuits that provide the neural substrate for goal-directed corrections, an essential aspect of highly skilled motor behaviors. DOI: http://dx.doi.org/10.7554/eLife.13141.001 PMID:27077949
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Vacillation, indecision and hesitation in moment-by-moment decoding of monkey motor cortex
Kaufman, Matthew T; Churchland, Mark M; Ryu, Stephen I; Shenoy, Krishna V
2015-01-01
When choosing actions, we can act decisively, vacillate, or suffer momentary indecision. Studying how individual decisions unfold requires moment-by-moment readouts of brain state. Here we provide such a view from dorsal premotor and primary motor cortex. Two monkeys performed a novel decision task while we recorded from many neurons simultaneously. We found that a decoder trained using ‘forced choices’ (one target viable) was highly reliable when applied to ‘free choices’. However, during free choices internal events formed three categories. Typically, neural activity was consistent with rapid, unwavering choices. Sometimes, though, we observed presumed ‘changes of mind’: the neural state initially reflected one choice before changing to reflect the final choice. Finally, we observed momentary ‘indecision’: delay forming any clear motor plan. Further, moments of neural indecision accompanied moments of behavioral indecision. Together, these results reveal the rich and diverse set of internal events long suspected to occur during free choice. DOI: http://dx.doi.org/10.7554/eLife.04677.001 PMID:25942352
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Buffered Qualitative Stability explains the robustness and evolvability of transcriptional networks
Albergante, Luca; Blow, J Julian; Newman, Timothy J
2014-01-01
The gene regulatory network (GRN) is the central decision‐making module of the cell. We have developed a theory called Buffered Qualitative Stability (BQS) based on the hypothesis that GRNs are organised so that they remain robust in the face of unpredictable environmental and evolutionary changes. BQS makes strong and diverse predictions about the network features that allow stable responses under arbitrary perturbations, including the random addition of new connections. We show that the GRNs of E. coli, M. tuberculosis, P. aeruginosa, yeast, mouse, and human all verify the predictions of BQS. BQS explains many of the small- and large‐scale properties of GRNs, provides conditions for evolvable robustness, and highlights general features of transcriptional response. BQS is severely compromised in a human cancer cell line, suggesting that loss of BQS might underlie the phenotypic plasticity of cancer cells, and highlighting a possible sequence of GRN alterations concomitant with cancer initiation. DOI: http://dx.doi.org/10.7554/eLife.02863.001 PMID:25182846
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Stapled Golgi cisternae remain in place as cargo passes through the stack
Lavieu, Gregory; Zheng, Hong; Rothman, James E
2013-01-01
We have designed a membrane ‘staple’, which consists of membrane-anchored repeats of the trans-aggregating FM domain that face the lumen of the secretory pathway. In the presence of the disaggregating drug these proteins transit the secretory pathway. When the drug is removed these proteins form electron-dense plaques which we term staples. Unexpectedly, when initially positioned within the cis-Golgi, staples remained at the cis face of the Golgi even after many hours. By contrast, soluble FM-aggregates transited the Golgi. Staples and soluble aggregates placed in cis-Golgi cisternae therefore have different fates. Whereas the membrane staples are located in the flattened, stacked central regions of the cisternae, the soluble aggregates are in the dilated rims. This suggests that while the cisternae are static on the time scale of protein traffic, the dilated rims are mobile and progress in the cis → trans direction via a mechanism that we term ‘Rim Progression’. DOI: http://dx.doi.org/10.7554/eLife.00558.001 PMID:23755362
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Cohen, Jeremy D; Bolstad, Mark; Lee, Albert K
2017-01-01
The hippocampus is critical for producing stable representations of familiar spaces. How these representations arise is poorly understood, largely because changes to hippocampal inputs have not been measured during spatial learning. Here, using intracellular recording, we monitored inputs and plasticity-inducing complex spikes (CSs) in CA1 neurons while mice explored novel and familiar virtual environments. Inputs driving place field spiking increased in amplitude – often suddenly – during novel environment exploration. However, these increases were not sustained in familiar environments. Rather, the spatial tuning of inputs became increasingly similar across repeated traversals of the environment with experience – both within fields and throughout the whole environment. In novel environments, CSs were not necessary for place field formation. Our findings support a model in which initial inhomogeneities in inputs are amplified to produce robust place field activity, then plasticity refines this representation into one with less strongly modulated, but more stable, inputs for long-term storage. DOI: http://dx.doi.org/10.7554/eLife.23040.001 PMID:28742496
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Bacterial flagella grow through an injection-diffusion mechanism
Renault, Thibaud T; Abraham, Anthony O; Bergmiller, Tobias; Paradis, Guillaume; Rainville, Simon; Charpentier, Emmanuelle; Guet, Călin C; Tu, Yuhai; Namba, Keiichi; Keener, James P; Minamino, Tohru; Erhardt, Marc
2017-01-01
The bacterial flagellum is a self-assembling nanomachine. The external flagellar filament, several times longer than a bacterial cell body, is made of a few tens of thousands subunits of a single protein: flagellin. A fundamental problem concerns the molecular mechanism of how the flagellum grows outside the cell, where no discernible energy source is available. Here, we monitored the dynamic assembly of individual flagella using in situ labelling and real-time immunostaining of elongating flagellar filaments. We report that the rate of flagellum growth, initially ∼1,700 amino acids per second, decreases with length and that the previously proposed chain mechanism does not contribute to the filament elongation dynamics. Inhibition of the proton motive force-dependent export apparatus revealed a major contribution of substrate injection in driving filament elongation. The combination of experimental and mathematical evidence demonstrates that a simple, injection-diffusion mechanism controls bacterial flagella growth outside the cell. DOI: http://dx.doi.org/10.7554/eLife.23136.001 PMID:28262091
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Ongoing resolution of duplicate gene functions shapes the diversification of a metabolic network
Kuang, Meihua Christina; Hutchins, Paul D; Russell, Jason D; Coon, Joshua J; Hittinger, Chris Todd
2016-01-01
The evolutionary mechanisms leading to duplicate gene retention are well understood, but the long-term impacts of paralog differentiation on the regulation of metabolism remain underappreciated. Here we experimentally dissect the functions of two pairs of ancient paralogs of the GALactose sugar utilization network in two yeast species. We show that the Saccharomyces uvarum network is more active, even as over-induction is prevented by a second co-repressor that the model yeast Saccharomyces cerevisiae lacks. Surprisingly, removal of this repression system leads to a strong growth arrest, likely due to overly rapid galactose catabolism and metabolic overload. Alternative sugars, such as fructose, circumvent metabolic control systems and exacerbate this phenotype. We further show that S. cerevisiae experiences homologous metabolic constraints that are subtler due to how the paralogs have diversified. These results show how the functional differentiation of paralogs continues to shape regulatory network architectures and metabolic strategies long after initial preservation. DOI: http://dx.doi.org/10.7554/eLife.19027.001 PMID:27690225
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A molecular mechanism of mitotic centrosome assembly in Drosophila
Conduit, Paul T; Richens, Jennifer H; Wainman, Alan; Holder, James; Vicente, Catarina C; Pratt, Metta B; Dix, Carly I; Novak, Zsofia A; Dobbie, Ian M; Schermelleh, Lothar; Raff, Jordan W
2014-01-01
Centrosomes comprise a pair of centrioles surrounded by pericentriolar material (PCM). The PCM expands dramatically as cells enter mitosis, but it is unclear how this occurs. In this study, we show that the centriole protein Asl initiates the recruitment of DSpd-2 and Cnn to mother centrioles; both proteins then assemble into co-dependent scaffold-like structures that spread outwards from the mother centriole and recruit most, if not all, other PCM components. In the absence of either DSpd-2 or Cnn, mitotic PCM assembly is diminished; in the absence of both proteins, it appears to be abolished. We show that DSpd-2 helps incorporate Cnn into the PCM and that Cnn then helps maintain DSpd-2 within the PCM, creating a positive feedback loop that promotes robust PCM expansion around the mother centriole during mitosis. These observations suggest a surprisingly simple mechanism of mitotic PCM assembly in flies. DOI: http://dx.doi.org/10.7554/eLife.03399.001 PMID:25149451
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Reconceiving the hippocampal map as a topological template
Dabaghian, Yuri; Brandt, Vicky L; Frank, Loren M
2014-01-01
The role of the hippocampus in spatial cognition is incontrovertible yet controversial. Place cells, initially thought to be location-specifiers, turn out to respond promiscuously to a wide range of stimuli. Here we test the idea, which we have recently demonstrated in a computational model, that the hippocampal place cells may ultimately be interested in a space's topological qualities (its connectivity) more than its geometry (distances and angles); such higher-order functioning would be more consistent with other known hippocampal functions. We recorded place cell activity in rats exploring morphing linear tracks that allowed us to dissociate the geometry of the track from its topology. The resulting place fields preserved the relative sequence of places visited along the track but did not vary with the metrical features of the track or the direction of the rat's movement. These results suggest a reinterpretation of previous studies and new directions for future experiments. DOI: http://dx.doi.org/10.7554/eLife.03476.001 PMID:25141375
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The kinetochore prevents centromere-proximal crossover recombination during meiosis
Vincenten, Nadine; Kuhl, Lisa-Marie; Lam, Isabel; Oke, Ashwini; Kerr, Alastair RW; Hochwagen, Andreas; Fung, Jennifer; Keeney, Scott; Vader, Gerben; Marston, Adèle L
2015-01-01
During meiosis, crossover recombination is essential to link homologous chromosomes and drive faithful chromosome segregation. Crossover recombination is non-random across the genome, and centromere-proximal crossovers are associated with an increased risk of aneuploidy, including Trisomy 21 in humans. Here, we identify the conserved Ctf19/CCAN kinetochore sub-complex as a major factor that minimizes potentially deleterious centromere-proximal crossovers in budding yeast. We uncover multi-layered suppression of pericentromeric recombination by the Ctf19 complex, operating across distinct chromosomal distances. The Ctf19 complex prevents meiotic DNA break formation, the initiating event of recombination, proximal to the centromere. The Ctf19 complex independently drives the enrichment of cohesin throughout the broader pericentromere to suppress crossovers, but not DNA breaks. This non-canonical role of the kinetochore in defining a chromosome domain that is refractory to crossovers adds a new layer of functionality by which the kinetochore prevents the incidence of chromosome segregation errors that generate aneuploid gametes. DOI: http://dx.doi.org/10.7554/eLife.10850.001 PMID:26653857
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Lotka-Volterra pairwise modeling fails to capture diverse pairwise microbial interactions
Momeni, Babak; Xie, Li; Shou, Wenying
2017-01-01
Pairwise models are commonly used to describe many-species communities. In these models, an individual receives additive fitness effects from pairwise interactions with each species in the community ('additivity assumption'). All pairwise interactions are typically represented by a single equation where parameters reflect signs and strengths of fitness effects ('universality assumption'). Here, we show that a single equation fails to qualitatively capture diverse pairwise microbial interactions. We build mechanistic reference models for two microbial species engaging in commonly-found chemical-mediated interactions, and attempt to derive pairwise models. Different equations are appropriate depending on whether a mediator is consumable or reusable, whether an interaction is mediated by one or more mediators, and sometimes even on quantitative details of the community (e.g. relative fitness of the two species, initial conditions). Our results, combined with potential violation of the additivity assumption in many-species communities, suggest that pairwise modeling will often fail to predict microbial dynamics. DOI: http://dx.doi.org/10.7554/eLife.25051.001 PMID:28350295
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Mechanism for priming DNA synthesis by yeast DNA Polymerase α
Perera, Rajika L; Torella, Rubben; Klinge, Sebastian; Kilkenny, Mairi L; Maman, Joseph D; Pellegrini, Luca
2013-01-01
The DNA Polymerase α (Pol α)/primase complex initiates DNA synthesis in eukaryotic replication. In the complex, Pol α and primase cooperate in the production of RNA-DNA oligonucleotides that prime synthesis of new DNA. Here we report crystal structures of the catalytic core of yeast Pol α in unliganded form, bound to an RNA primer/DNA template and extending an RNA primer with deoxynucleotides. We combine the structural analysis with biochemical and computational data to demonstrate that Pol α specifically recognizes the A-form RNA/DNA helix and that the ensuing synthesis of B-form DNA terminates primer synthesis. The spontaneous release of the completed RNA-DNA primer by the Pol α/primase complex simplifies current models of primer transfer to leading- and lagging strand polymerases. The proposed mechanism of nucleotide polymerization by Pol α might contribute to genomic stability by limiting the amount of inaccurate DNA to be corrected at the start of each Okazaki fragment. DOI: http://dx.doi.org/10.7554/eLife.00482.001 PMID:23599895
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Smith, Benjamin A; Padrick, Shae B; Doolittle, Lynda K; Daugherty-Clarke, Karen; Corrêa, Ivan R; Xu, Ming-Qun; Goode, Bruce L; Rosen, Michael K; Gelles, Jeff
2013-09-03
During cell locomotion and endocytosis, membrane-tethered WASP proteins stimulate actin filament nucleation by the Arp2/3 complex. This process generates highly branched arrays of filaments that grow toward the membrane to which they are tethered, a conflict that seemingly would restrict filament growth. Using three-color single-molecule imaging in vitro we revealed how the dynamic associations of Arp2/3 complex with mother filament and WASP are temporally coordinated with initiation of daughter filament growth. We found that WASP proteins dissociated from filament-bound Arp2/3 complex prior to new filament growth. Further, mutations that accelerated release of WASP from filament-bound Arp2/3 complex proportionally accelerated branch formation. These data suggest that while WASP promotes formation of pre-nucleation complexes, filament growth cannot occur until it is triggered by WASP release. This provides a mechanism by which membrane-bound WASP proteins can stimulate network growth without restraining it. DOI:http://dx.doi.org/10.7554/eLife.01008.001.
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Menegas, William; Babayan, Benedicte M; Uchida, Naoshige; Watabe-Uchida, Mitsuko
2017-01-01
Dopamine neurons are thought to encode novelty in addition to reward prediction error (the discrepancy between actual and predicted values). In this study, we compared dopamine activity across the striatum using fiber fluorometry in mice. During classical conditioning, we observed opposite dynamics in dopamine axon signals in the ventral striatum (‘VS dopamine’) and the posterior tail of the striatum (‘TS dopamine’). TS dopamine showed strong excitation to novel cues, whereas VS dopamine showed no responses to novel cues until they had been paired with a reward. TS dopamine cue responses decreased over time, depending on what the cue predicted. Additionally, TS dopamine showed excitation to several types of stimuli including rewarding, aversive, and neutral stimuli whereas VS dopamine showed excitation only to reward or reward-predicting cues. Together, these results demonstrate that dopamine novelty signals are localized in TS along with general salience signals, while VS dopamine reliably encodes reward prediction error. DOI: http://dx.doi.org/10.7554/eLife.21886.001 PMID:28054919
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Spatial self-organization favors heterotypic cooperation over cheating.
Momeni, Babak; Waite, Adam James; Shou, Wenying
2013-11-12
Heterotypic cooperation-two populations exchanging distinct benefits that are costly to produce-is widespread. Cheaters, exploiting benefits while evading contribution, can undermine cooperation. Two mechanisms can stabilize heterotypic cooperation. In 'partner choice', cooperators recognize and choose cooperating over cheating partners; in 'partner fidelity feedback', fitness-feedback from repeated interactions ensures that aiding your partner helps yourself. How might a spatial environment, which facilitates repeated interactions, promote fitness-feedback? We examined this process through mathematical models and engineered Saccharomyces cerevisiae strains incapable of recognition. Here, cooperators and their heterotypic cooperative partners (partners) exchanged distinct essential metabolites. Cheaters exploited partner-produced metabolites without reciprocating, and were competitively superior to cooperators. Despite initially random spatial distributions, cooperators gained more partner neighbors than cheaters did. The less a cheater contributed, the more it was excluded and disfavored. This self-organization, driven by asymmetric fitness effects of cooperators and cheaters on partners during cell growth into open space, achieves assortment. DOI: http://dx.doi.org/10.7554/eLife.00960.001.
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Spatial self-organization favors heterotypic cooperation over cheating
Momeni, Babak; Waite, Adam James; Shou, Wenying
2013-01-01
Heterotypic cooperation—two populations exchanging distinct benefits that are costly to produce—is widespread. Cheaters, exploiting benefits while evading contribution, can undermine cooperation. Two mechanisms can stabilize heterotypic cooperation. In ‘partner choice’, cooperators recognize and choose cooperating over cheating partners; in ‘partner fidelity feedback’, fitness-feedback from repeated interactions ensures that aiding your partner helps yourself. How might a spatial environment, which facilitates repeated interactions, promote fitness-feedback? We examined this process through mathematical models and engineered Saccharomyces cerevisiae strains incapable of recognition. Here, cooperators and their heterotypic cooperative partners (partners) exchanged distinct essential metabolites. Cheaters exploited partner-produced metabolites without reciprocating, and were competitively superior to cooperators. Despite initially random spatial distributions, cooperators gained more partner neighbors than cheaters did. The less a cheater contributed, the more it was excluded and disfavored. This self-organization, driven by asymmetric fitness effects of cooperators and cheaters on partners during cell growth into open space, achieves assortment. DOI: http://dx.doi.org/10.7554/eLife.00960.001 PMID:24220506
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Miyazaki, Yusuke; Chen, Ling-chun; Chu, Bernard W; Swigut, Tomek; Wandless, Thomas J
2015-01-01
Eukaryotic cells possess a variety of signaling pathways that prevent accumulation of unfolded and misfolded proteins. Chief among these is the heat shock response (HSR), which is assumed to respond to unfolded proteins in the cytosol and nucleus alike. In this study, we probe this axiom further using engineered proteins called ‘destabilizing domains’, whose folding state we control with a small molecule. The sudden appearance of unfolded protein in mammalian cells elicits a robust transcriptional response, which is distinct from the HSR and other known pathways that respond to unfolded proteins. The cellular response to unfolded protein is strikingly different in the nucleus and the cytosol, although unfolded protein in either compartment engages the p53 network. This response provides cross-protection during subsequent proteotoxic stress, suggesting that it is a central component of protein quality control networks, and like the HSR, is likely to influence the initiation and progression of human pathologies. DOI: http://dx.doi.org/10.7554/eLife.07687.001 PMID:26314864
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Temporal dynamics and developmental memory of 3D chromatin architecture at Hox gene loci
Noordermeer, Daan; Leleu, Marion; Schorderet, Patrick; Joye, Elisabeth; Chabaud, Fabienne; Duboule, Denis
2014-01-01
Hox genes are essential regulators of embryonic development. Their step-wise transcriptional activation follows their genomic topology and the various states of activation are subsequently memorized into domains of progressively overlapping gene products. We have analyzed the 3D chromatin organization of Hox clusters during their early activation in vivo, using high-resolution circular chromosome conformation capture. Initially, Hox clusters are organized as single chromatin compartments containing all genes and bivalent chromatin marks. Transcriptional activation is associated with a dynamic bi-modal 3D organization, whereby the genes switch autonomously from an inactive to an active compartment. These local 3D dynamics occur within a framework of constitutive interactions within the surrounding Topological Associated Domains, indicating that this regulation process is mostly cluster intrinsic. The step-wise progression in time is fixed at various body levels and thus can account for the chromatin architectures previously described at a later stage for different anterior to posterior levels. DOI: http://dx.doi.org/10.7554/eLife.02557.001 PMID:24843030
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Su, Ting; Cheng, Jingdong; Sohmen, Daniel; Hedman, Rickard; Berninghausen, Otto; von Heijne, Gunnar; Wilson, Daniel N; Beckmann, Roland
2017-01-01
Interaction between the nascent polypeptide chain and the ribosomal exit tunnel can modulate the rate of translation and induce translational arrest to regulate expression of downstream genes. The ribosomal tunnel also provides a protected environment for initial protein folding events. Here, we present a 2.9 Å cryo-electron microscopy structure of a ribosome stalled during translation of the extremely compacted VemP nascent chain. The nascent chain forms two α-helices connected by an α-turn and a loop, enabling a total of 37 amino acids to be observed within the first 50–55 Å of the exit tunnel. The structure reveals how α-helix formation directly within the peptidyltransferase center of the ribosome interferes with aminoacyl-tRNA accommodation, suggesting that during canonical translation, a major role of the exit tunnel is to prevent excessive secondary structure formation that can interfere with the peptidyltransferase activity of the ribosome. DOI: http://dx.doi.org/10.7554/eLife.25642.001 PMID:28556777
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Voelzmann, Andre; Okenve-Ramos, Pilar; Qu, Yue; Chojnowska-Monga, Monika; del Caño-Espinel, Manuela; Prokop, Andreas; Sanchez-Soriano, Natalia
2016-01-01
The mechanisms regulating synapse numbers during development and ageing are essential for normal brain function and closely linked to brain disorders including dementias. Using Drosophila, we demonstrate roles of the microtubule-associated protein Tau in regulating synapse numbers, thus unravelling an important cellular requirement of normal Tau. In this context, we find that Tau displays a strong functional overlap with microtubule-binding spectraplakins, establishing new links between two different neurodegenerative factors. Tau and the spectraplakin Short Stop act upstream of a three-step regulatory cascade ensuring adequate delivery of synaptic proteins. This cascade involves microtubule stability as the initial trigger, JNK signalling as the central mediator, and kinesin-3 mediated axonal transport as the key effector. This cascade acts during development (synapse formation) and ageing (synapse maintenance) alike. Therefore, our findings suggest novel explanations for intellectual disability in Tau deficient individuals, as well as early synapse loss in dementias including Alzheimer’s disease. DOI: http://dx.doi.org/10.7554/eLife.14694.001 PMID:27501441
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Global, quantitative and dynamic mapping of protein subcellular localization
Itzhak, Daniel N; Tyanova, Stefka; Cox, Jürgen; Borner, Georg HH
2016-01-01
Subcellular localization critically influences protein function, and cells control protein localization to regulate biological processes. We have developed and applied Dynamic Organellar Maps, a proteomic method that allows global mapping of protein translocation events. We initially used maps statically to generate a database with localization and absolute copy number information for over 8700 proteins from HeLa cells, approaching comprehensive coverage. All major organelles were resolved, with exceptional prediction accuracy (estimated at >92%). Combining spatial and abundance information yielded an unprecedented quantitative view of HeLa cell anatomy and organellar composition, at the protein level. We subsequently demonstrated the dynamic capabilities of the approach by capturing translocation events following EGF stimulation, which we integrated into a quantitative model. Dynamic Organellar Maps enable the proteome-wide analysis of physiological protein movements, without requiring any reagents specific to the investigated process, and will thus be widely applicable in cell biology. DOI: http://dx.doi.org/10.7554/eLife.16950.001 PMID:27278775
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Disruption of glycolytic flux is a signal for inflammasome signaling and pyroptotic cell death
Sanman, Laura E; Qian, Yu; Eisele, Nicholas A; Ng, Tessie M; van der Linden, Wouter A; Monack, Denise M; Weerapana, Eranthie; Bogyo, Matthew
2016-01-01
When innate immune cells such as macrophages are challenged with environmental stresses or infection by pathogens, they trigger the rapid assembly of multi-protein complexes called inflammasomes that are responsible for initiating pro-inflammatory responses and a form of cell death termed pyroptosis. We describe here the identification of an intracellular trigger of NLRP3-mediated inflammatory signaling, IL-1β production and pyroptosis in primed murine bone marrow-derived macrophages that is mediated by the disruption of glycolytic flux. This signal results from a drop of NADH levels and induction of mitochondrial ROS production and can be rescued by addition of products that restore NADH production. This signal is also important for host-cell response to the intracellular pathogen Salmonella typhimurium, which can disrupt metabolism by uptake of host-cell glucose. These results reveal an important inflammatory signaling network used by immune cells to sense metabolic dysfunction or infection by intracellular pathogens. DOI: http://dx.doi.org/10.7554/eLife.13663.001 PMID:27011353
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Mouse rods signal through gap junctions with cones.
Asteriti, Sabrina; Gargini, Claudia; Cangiano, Lorenzo
2014-01-01
Rod and cone photoreceptors are coupled by gap junctions (GJs), relatively large channels able to mediate both electrical and molecular communication. Despite their critical location in our visual system and evidence that they are dynamically gated for dark/light adaptation, the full impact that rod-cone GJs can have on cone function is not known. We recorded the photovoltage of mouse cones and found that the initial level of rod input increased spontaneously after obtaining intracellular access. This process allowed us to explore the underlying coupling capacity to rods, revealing that fully coupled cones acquire a striking rod-like phenotype. Calcium, a candidate mediator of the coupling process, does not appear to be involved on the cone side of the junctional channels. Our findings show that the anatomical substrate is adequate for rod-cone coupling to play an important role in vision and, possibly, in biochemical signaling among photoreceptors. DOI: http://dx.doi.org/10.7554/eLife.01386.001.
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Hasegawa, Tomoya; Hall, Christopher J; Crosier, Philip S; Abe, Gembu; Kawakami, Koichi; Kudo, Akira; Kawakami, Atsushi
2017-01-01
Cellular responses to injury are crucial for complete tissue regeneration, but their underlying processes remain incompletely elucidated. We have previously reported that myeloid-defective zebrafish mutants display apoptosis of regenerative cells during fin fold regeneration. Here, we found that the apoptosis phenotype is induced by prolonged expression of interleukin 1 beta (il1b). Myeloid cells are considered to be the principal source of Il1b, but we show that epithelial cells express il1b in response to tissue injury and initiate the inflammatory response, and that its resolution by macrophages is necessary for survival of regenerative cells. We further show that Il1b plays an essential role in normal fin fold regeneration by regulating expression of regeneration-induced genes. Our study reveals that proper levels of Il1b signaling and tissue inflammation, which are tuned by macrophages, play a crucial role in tissue regeneration. DOI: http://dx.doi.org/10.7554/eLife.22716.001 PMID:28229859
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Network structure of brain atrophy in de novo Parkinson's disease
Zeighami, Yashar; Ulla, Miguel; Iturria-Medina, Yasser; Dadar, Mahsa; Zhang, Yu; Larcher, Kevin Michel-Herve; Fonov, Vladimir; Evans, Alan C; Collins, D Louis; Dagher, Alain
2015-01-01
We mapped the distribution of atrophy in Parkinson's disease (PD) using magnetic resonance imaging (MRI) and clinical data from 232 PD patients and 117 controls from the Parkinson's Progression Markers Initiative. Deformation-based morphometry and independent component analysis identified PD-specific atrophy in the midbrain, basal ganglia, basal forebrain, medial temporal lobe, and discrete cortical regions. The degree of atrophy reflected clinical measures of disease severity. The spatial pattern of atrophy demonstrated overlap with intrinsic networks present in healthy brain, as derived from functional MRI. Moreover, the degree of atrophy in each brain region reflected its functional and anatomical proximity to a presumed disease epicenter in the substantia nigra, compatible with a trans-neuronal spread of the disease. These results support a network-spread mechanism in PD. Finally, the atrophy pattern in PD was also seen in healthy aging, where it also correlated with the loss of striatal dopaminergic innervation. DOI: http://dx.doi.org/10.7554/eLife.08440.001 PMID:26344547
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Brown, Jennifer; Pan, Wei-Xing; Dudman, Joshua Tate
2014-01-01
Dysfunction of the basal ganglia produces severe deficits in the timing, initiation, and vigor of movement. These diverse impairments suggest a control system gone awry. In engineered systems, feedback is critical for control. By contrast, models of the basal ganglia highlight feedforward circuitry and ignore intrinsic feedback circuits. In this study, we show that feedback via axon collaterals of substantia nigra projection neurons control the gain of the basal ganglia output. Through a combination of physiology, optogenetics, anatomy, and circuit mapping, we elaborate a general circuit mechanism for gain control in a microcircuit lacking interneurons. Our data suggest that diverse tonic firing rates, weak unitary connections and a spatially diffuse collateral circuit with distinct topography and kinetics from feedforward input is sufficient to implement divisive feedback inhibition. The importance of feedback for engineered systems implies that the intranigral microcircuit, despite its absence from canonical models, could be essential to basal ganglia function. DOI: http://dx.doi.org/10.7554/eLife.02397.001 PMID:24849626
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Mouse rods signal through gap junctions with cones
Asteriti, Sabrina; Gargini, Claudia; Cangiano, Lorenzo
2014-01-01
Rod and cone photoreceptors are coupled by gap junctions (GJs), relatively large channels able to mediate both electrical and molecular communication. Despite their critical location in our visual system and evidence that they are dynamically gated for dark/light adaptation, the full impact that rod–cone GJs can have on cone function is not known. We recorded the photovoltage of mouse cones and found that the initial level of rod input increased spontaneously after obtaining intracellular access. This process allowed us to explore the underlying coupling capacity to rods, revealing that fully coupled cones acquire a striking rod-like phenotype. Calcium, a candidate mediator of the coupling process, does not appear to be involved on the cone side of the junctional channels. Our findings show that the anatomical substrate is adequate for rod–cone coupling to play an important role in vision and, possibly, in biochemical signaling among photoreceptors. DOI: http://dx.doi.org/10.7554/eLife.01386.001 PMID:24399457
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Carbon recovery dynamics following disturbance by selective logging in Amazonian forests
Piponiot, Camille; Sist, Plinio; Mazzei, Lucas; Peña-Claros, Marielos; Putz, Francis E; Rutishauser, Ervan; Shenkin, Alexander; Ascarrunz, Nataly; de Azevedo, Celso P; Baraloto, Christopher; França, Mabiane; Guedes, Marcelino; Honorio Coronado, Eurídice N; d'Oliveira, Marcus VN; Ruschel, Ademir R; da Silva, Kátia E; Doff Sotta, Eleneide; de Souza, Cintia R; Vidal, Edson; West, Thales AP; Hérault, Bruno
2016-01-01
When 2 Mha of Amazonian forests are disturbed by selective logging each year, more than 90 Tg of carbon (C) is emitted to the atmosphere. Emissions are then counterbalanced by forest regrowth. With an original modelling approach, calibrated on a network of 133 permanent forest plots (175 ha total) across Amazonia, we link regional differences in climate, soil and initial biomass with survivors’ and recruits’ C fluxes to provide Amazon-wide predictions of post-logging C recovery. We show that net aboveground C recovery over 10 years is higher in the Guiana Shield and in the west (21 ±3 Mg C ha-1) than in the south (12 ±3 Mg C ha-1) where environmental stress is high (low rainfall, high seasonality). We highlight the key role of survivors in the forest regrowth and elaborate a comprehensive map of post-disturbance C recovery potential in Amazonia. DOI: http://dx.doi.org/10.7554/eLife.21394.001 PMID:27993185
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Novel adverse outcome pathways revealed by chemical genetics in a developing marine fish
Sørhus, Elin; Incardona, John P; Furmanek, Tomasz; Goetz, Giles W; Scholz, Nathaniel L; Meier, Sonnich; Edvardsen, Rolf B; Jentoft, Sissel
2017-01-01
Crude oil spills are a worldwide ocean conservation threat. Fish are particularly vulnerable to the oiling of spawning habitats, and crude oil causes severe abnormalities in embryos and larvae. However, the underlying mechanisms for these developmental defects are not well understood. Here, we explore the transcriptional basis for four discrete crude oil injury phenotypes in the early life stages of the commercially important Atlantic haddock (Melanogrammus aeglefinus). These include defects in (1) cardiac form and function, (2) craniofacial development, (3) ionoregulation and fluid balance, and (4) cholesterol synthesis and homeostasis. Our findings suggest a key role for intracellular calcium cycling and excitation-transcription coupling in the dysregulation of heart and jaw morphogenesis. Moreover, the disruption of ionoregulatory pathways sheds new light on buoyancy control in marine fish embryos. Overall, our chemical-genetic approach identifies initiating events for distinct adverse outcome pathways and novel roles for individual genes in fundamental developmental processes. DOI: http://dx.doi.org/10.7554/eLife.20707.001 PMID:28117666
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Igloi, Kinga; Gaggioni, Giulia; Sterpenich, Virginie; Schwartz, Sophie
2015-01-01
Sleep plays a crucial role in the consolidation of newly acquired memories. Yet, how our brain selects the noteworthy information that will be consolidated during sleep remains largely unknown. Here we show that post-learning sleep favors the selectivity of long-term consolidation: when tested three months after initial encoding, the most important (i.e., rewarded, strongly encoded) memories are better retained, and also remembered with higher subjective confidence. Our brain imaging data reveals that the functional interplay between dopaminergic reward regions, the prefrontal cortex and the hippocampus contributes to the integration of rewarded associative memories. We further show that sleep spindles strengthen memory representations based on reward values, suggesting a privileged replay of information yielding positive outcomes. These findings demonstrate that post-learning sleep determines the neural fate of motivationally-relevant memories and promotes a value-based stratification of long-term memory stores. DOI: http://dx.doi.org/10.7554/eLife.07903.001 PMID:26473618
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Mechanism and preclinical prevention of increased breast cancer risk caused by pregnancy.
Haricharan, Svasti; Dong, Jie; Hein, Sarah; Reddy, Jay P; Du, Zhijun; Toneff, Michael; Holloway, Kimberly; Hilsenbeck, Susan G; Huang, Shixia; Atkinson, Rachel; Woodward, Wendy; Jindal, Sonali; Borges, Virginia F; Gutierrez, Carolina; Zhang, Hong; Schedin, Pepper J; Osborne, C Kent; Tweardy, David J; Li, Yi
2013-12-31
While a first pregnancy before age 22 lowers breast cancer risk, a pregnancy after age 35 significantly increases life-long breast cancer risk. Pregnancy causes several changes to the normal breast that raise barriers to transformation, but how pregnancy can also increase cancer risk remains unclear. We show in mice that pregnancy has different effects on the few early lesions that have already developed in the otherwise normal breast-it causes apoptosis evasion and accelerated progression to cancer. The apoptosis evasion is due to the normally tightly controlled STAT5 signaling going astray-these precancerous cells activate STAT5 in response to pregnancy/lactation hormones and maintain STAT5 activation even during involution, thus preventing the apoptosis normally initiated by oncoprotein and involution. Short-term anti-STAT5 treatment of lactation-completed mice bearing early lesions eliminates the increased risk after a pregnancy. This chemoprevention strategy has important implications for preventing increased human breast cancer risk caused by pregnancy. DOI: http://dx.doi.org/10.7554/eLife.00996.001.
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Causal role for the subthalamic nucleus in interrupting behavior
Fife, Kathryn H; Gutierrez-Reed, Navarre A; Zell, Vivien; Bailly, Julie; Lewis, Christina M; Aron, Adam R; Hnasko, Thomas S
2017-01-01
Stopping or pausing in response to threats, conflicting information, or surprise is fundamental to behavior. Evidence across species has shown that the subthalamic nucleus (STN) is activated by scenarios involving stopping or pausing, yet evidence that the STN causally implements stops or pauses is lacking. Here we used optogenetics to activate or inhibit mouse STN to test its putative causal role. We first demonstrated that optogenetic stimulation of the STN excited its major projection targets. Next we showed that brief activation of STN projection neurons was sufficient to interrupt or pause a self-initiated bout of licking. Finally, we developed an assay in which surprise was used to interrupt licking, and showed that STN inhibition reduced the disruptive effect of surprise. Thus STN activation interrupts behavior, and blocking the STN blunts the interruptive effect of surprise. These results provide strong evidence that the STN is both necessary and sufficient for such forms of behavioral response suppression. DOI: http://dx.doi.org/10.7554/eLife.27689.001 PMID:28742497
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Three ancient hormonal cues co-ordinate shoot branching in a moss
Coudert, Yoan; Palubicki, Wojtek; Ljung, Karin; Novak, Ondrej; Leyser, Ottoline; Harrison, C Jill
2015-01-01
Shoot branching is a primary contributor to plant architecture, evolving independently in flowering plant sporophytes and moss gametophytes. Mechanistic understanding of branching is largely limited to flowering plants such as Arabidopsis, which have a recent evolutionary origin. We show that in gametophytic shoots of Physcomitrella, lateral branches arise by re-specification of epidermal cells into branch initials. A simple model co-ordinating the activity of leafy shoot tips can account for branching patterns, and three known and ancient hormonal regulators of sporophytic branching interact to generate the branching pattern- auxin, cytokinin and strigolactone. The mode of auxin transport required in branch patterning is a key divergence point from known sporophytic pathways. Although PIN-mediated basipetal auxin transport regulates branching patterns in flowering plants, this is not so in Physcomitrella, where bi-directional transport is required to generate realistic branching patterns. Experiments with callose synthesis inhibitors suggest plasmodesmal connectivity as a potential mechanism for transport. DOI: http://dx.doi.org/10.7554/eLife.06808.001 PMID:25806686
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Santos, Jorge M; Egarter, Saskia; Zuzarte-Luís, Vanessa; Kumar, Hirdesh; Moreau, Catherine A; Kehrer, Jessica; Pinto, Andreia; da Costa, Mário; Franke-Fayard, Blandine; Janse, Chris J; Frischknecht, Friedrich; Mair, Gunnar R
2017-01-01
Gliding motility allows malaria parasites to migrate and invade tissues and cells in different hosts. It requires parasite surface proteins to provide attachment to host cells and extracellular matrices. Here, we identify the Plasmodium protein LIMP (the name refers to a gliding phenotype in the sporozoite arising from epitope tagging of the endogenous protein) as a key regulator for adhesion during gliding motility in the rodent malaria model P. berghei. Transcribed in gametocytes, LIMP is translated in the ookinete from maternal mRNA, and later in the sporozoite. The absence of LIMP reduces initial mosquito infection by 50%, impedes salivary gland invasion 10-fold, and causes a complete absence of liver invasion as mutants fail to attach to host cells. GFP tagging of LIMP caused a limping defect during movement with reduced speed and transient curvature changes of the parasite. LIMP is an essential motility and invasion factor necessary for malaria transmission. DOI: http://dx.doi.org/10.7554/eLife.24109.001 PMID:28525314
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Refahi, Yassin; Brunoud, Géraldine; Farcot, Etienne; Jean-Marie, Alain; Pulkkinen, Minna; Vernoux, Teva; Godin, Christophe
2016-01-01
Exploration of developmental mechanisms classically relies on analysis of pattern regularities. Whether disorders induced by biological noise may carry information on building principles of developmental systems is an important debated question. Here, we addressed theoretically this question using phyllotaxis, the geometric arrangement of plant aerial organs, as a model system. Phyllotaxis arises from reiterative organogenesis driven by lateral inhibitions at the shoot apex. Motivated by recurrent observations of disorders in phyllotaxis patterns, we revisited in depth the classical deterministic view of phyllotaxis. We developed a stochastic model of primordia initiation at the shoot apex, integrating locality and stochasticity in the patterning system. This stochastic model recapitulates phyllotactic patterns, both regular and irregular, and makes quantitative predictions on the nature of disorders arising from noise. We further show that disorders in phyllotaxis instruct us on the parameters governing phyllotaxis dynamics, thus that disorders can reveal biological watermarks of developmental systems. DOI: http://dx.doi.org/10.7554/eLife.14093.001 PMID:27380805
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Data Publication: The Evolving Lifecyle
NASA Astrophysics Data System (ADS)
Studwell, S.; Elliott, J.; Anderson, A.
2015-12-01
Datasets are recognized as valuable information entities in their own right that, now and in the future, need to be available for citation, discovery, retrieval and reuse. The U.S. Department of Energy's Office of Scientific and Technical Information (OSTI) provides Digital Object Identifiers (DOIs) to DOE-funded data through partnership with DataCite. The Geothermal Data Repository (GDR) has been using OSTI's Data ID Service since summer, 2014 and is a success story for data publishing in several different ways. This presentation attributes the initial success to the insistence of DOE's Geothermal Technologies Office on detailed planning, robust data curation, and submitter participation. OSTI widely disseminates these data products across both U.S. and international platforms and continually enhances the Data ID Service to facilitate better linkage between published literature, supplementary data components, and the underlying datasets within the structure of the GDR repository. Issues of granularity in DOI assignment, the role of new federal government guidelines on public access to digital data, and the challenges still ahead will be addressed.
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Varela Minder, Elda; Padgett, Holly A.
2016-04-07
2015 was another great year for the Department of the Interior (DOI) Climate Science Centers (CSCs) and U.S. Geological Survey (USGS) National Climate Change and Wildlife Science Center (NCCWSC) network. The DOI CSCs and USGS NCCWSC continued their mission of providing the science, data, and tools that are needed for on-the-ground decision making by natural and cultural resource managers to address the effects of climate change on fish, wildlife, ecosystems, and communities. Our many accomplishments in 2015 included initiating a national effort to understand the influence of drought on wildlife and ecosystems; providing numerous opportunities for students and early career researchers to expand their networks and learn more about climate change effects; and working with tribes and indigenous communities to expand their knowledge of and preparation for the impacts of climate change on important resources and traditional ways of living. Here we illustrate some of these 2015 activities from across the CSCs and NCCWSC.
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Nuclear pore assembly proceeds by an inside-out extrusion of the nuclear envelope
Otsuka, Shotaro; Bui, Khanh Huy; Schorb, Martin; Hossain, M Julius; Politi, Antonio Z; Koch, Birgit; Eltsov, Mikhail; Beck, Martin; Ellenberg, Jan
2016-01-01
The nuclear pore complex (NPC) mediates nucleocytoplasmic transport through the nuclear envelope. How the NPC assembles into this double membrane boundary has remained enigmatic. Here, we captured temporally staged assembly intermediates by correlating live cell imaging with high-resolution electron tomography and super-resolution microscopy. Intermediates were dome-shaped evaginations of the inner nuclear membrane (INM), that grew in diameter and depth until they fused with the flat outer nuclear membrane. Live and super-resolved fluorescence microscopy revealed the molecular maturation of the intermediates, which initially contained the nuclear and cytoplasmic ring component Nup107, and only later the cytoplasmic filament component Nup358. EM particle averaging showed that the evagination base was surrounded by an 8-fold rotationally symmetric ring structure from the beginning and that a growing mushroom-shaped density was continuously associated with the deforming membrane. Quantitative structural analysis revealed that interphase NPC assembly proceeds by an asymmetric inside-out extrusion of the INM. DOI: http://dx.doi.org/10.7554/eLife.19071.001 PMID:27630123
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Cholesterol activates the G-protein coupled receptor Smoothened to promote Hedgehog signaling
Luchetti, Giovanni; Sircar, Ria; Kong, Jennifer H; Nachtergaele, Sigrid; Sagner, Andreas; Byrne, Eamon FX; Covey, Douglas F; Siebold, Christian; Rohatgi, Rajat
2016-01-01
Cholesterol is necessary for the function of many G-protein coupled receptors (GPCRs). We find that cholesterol is not just necessary but also sufficient to activate signaling by the Hedgehog (Hh) pathway, a prominent cell-cell communication system in development. Cholesterol influences Hh signaling by directly activating Smoothened (SMO), an orphan GPCR that transmits the Hh signal across the membrane in all animals. Unlike many GPCRs, which are regulated by cholesterol through their heptahelical transmembrane domains, SMO is activated by cholesterol through its extracellular cysteine-rich domain (CRD). Residues shown to mediate cholesterol binding to the CRD in a recent structural analysis also dictate SMO activation, both in response to cholesterol and to native Hh ligands. Our results show that cholesterol can initiate signaling from the cell surface by engaging the extracellular domain of a GPCR and suggest that SMO activity may be regulated by local changes in cholesterol abundance or accessibility. DOI: http://dx.doi.org/10.7554/eLife.20304.001 PMID:27705744
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Reliability beyond Theory and into Practice
ERIC Educational Resources Information Center
Sijtsma, Klaas
2009-01-01
The critical reactions of Bentler (2009, doi: 10.1007/s11336-008-9100-1), Green and Yang (2009a, doi: 10.1007/s11336-008-9098-4 ; 2009b, doi: 10.1007/s11336-008-9099-3), and Revelle and Zinbarg (2009, doi: 10.1007/s11336-008-9102-z) to Sijtsma's (2009, doi: 10.1007/s11336-008-9101-0) paper on Cronbach's alpha are addressed. The dissemination of…
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Link-Prediction Enhanced Consensus Clustering for Complex Networks (Open Access)
2016-05-20
92:022816. Available from: http://link.aps.org/doi/10.1103/PhysRevE.92.022816. doi: 10. 1103 /PhysRevE.92.022816 16. Aldecoa R, Marín I. Exploring the...from: http://link.aps.org/doi/10.1103/PhysRevE.80.056117. doi: 10. 1103 /PhysRevE.80.056117 18. Dahlin J, Svenson P. Ensemble approaches for improving...046110. Available from: http://link.aps.org/doi/10.1103/PhysRevE.81.046110. doi: 10. 1103 /PhysRevE.81.046110 28. Gfeller D, Chappelier JC, De Los Rios P
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Space Telescope optics. [large aperture astronomical instrument
NASA Technical Reports Server (NTRS)
Jones, C. O.
1979-01-01
The paper reviews the optical technology that has been developed over the last decade for the Space Telescope. The optical design of the telescope, the optical performance control system, and the anticipated optical performance are all presented. Consideration is also given to the initial complement of focal plane instruments.
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Promotion of Tumor-Initiating Cells in Primary and Recurrent Breast Tumors
2013-07-01
regulation of expression of genes which confer stemness . We hypothesize that inhibition of IKK/NF-κB will reduce or eliminate breast camcer TICs...Merkhofer et al., 2010). Baldwin, Albert S. W81XWH-12-1-0176 8 --Demonstrated that NF-κB is preferentially activated in breast cancer stem ...Breast cancer stem cells, cytokine networks, and the tumor microenvironment. J Clin Invest. 2011 Oct;121(10):3804-9. doi: 10.1172/JCI57099. Epub
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Year Five of Southeast Atlantic Coastal Ocean Observing System (SEACOOS) Implementation
2007-12-15
137 total]. Alvera -Azcarate, A., A. Barth, J.M. Beckers, and R.H. Weisberg, 2007. Multivariate reconstruction of missing data in sea surface...temperature, chlorophyll and wind satellite fields. Jour. Geophys. Res., 112, C03008, doi: 10.1029/2006JC003660. Alvera -Azcarate, A., A. Barth, and R.H...A., J.-M. Beckers, A. Alvera -Azcarate, and R. H. Weisberg, 2007. Filtering inertia-gravity waves from the initial conditions of the linear shallow
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Real time assessment of the 15 July 2009 New Zealand tsunami
NASA Astrophysics Data System (ADS)
Uslu, Burak; Power, William; Greensdale, Dianne; Titov, Vasily
2010-05-01
On the 15th July 2009 a Mw 7.6 earthquake occurred off the coast of Fiordland in the South Island of New Zealand, about 1200 km from Auckland, New Zealand, 1500 km from Hobart, Tasmania and 1800 km from Sydney, Australia. A tsunami was generated and an initial warning issued by the PTWC. The Centre for Australian Weather and Climate issued its first tsunami warning for coastal regions of eastern Australia and New Zealand 24 minutes after the earthquake. By serendipitous coincidence, the earthquake struck while the International Tsunami Symposium was in session in Novosibirsk Russia. This provided the opportunity to test, in real-time, several tsunami warning systems in front of attending scientists (Schiermeier, 2009). NOAA Center for Tsunami Research, Pacific Tsunami Warning Center, GNS Science, and Centre for Australian Weather and Climate scientists were present at the symposium and worked together. Vasily Titov showed "live" NOAA's methodology (Bernard et al, 2006) to assess the tsunami potential and, in consultation with colleagues, provided warning guidance, and the warning was eventually canceled. We discuss how the forecast was done and how accurate the initial determination was. References Bernard E.N. et al., 2006, Tsunami: scientific frontiers, mitigation, forecasting and policy implications, Phil. Trans. R. Soc. A, 364:1989-2007; doi:10.1098/rsta.2006.1809 Schiermeier, Q., 2009, Tsunami forecast in real time, Published online 16 July 2009 | Nature | doi:10.1038/news.2009.702
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Segmentation of optic disc and optic cup in retinal fundus images using shape regression.
Sedai, Suman; Roy, Pallab K; Mahapatra, Dwarikanath; Garnavi, Rahil
2016-08-01
Glaucoma is one of the leading cause of blindness. The manual examination of optic cup and disc is a standard procedure used for detecting glaucoma. This paper presents a fully automatic regression based method which accurately segments optic cup and disc in retinal colour fundus image. First, we roughly segment optic disc using circular hough transform. The approximated optic disc is then used to compute the initial optic disc and cup shapes. We propose a robust and efficient cascaded shape regression method which iteratively learns the final shape of the optic cup and disc from a given initial shape. Gradient boosted regression trees are employed to learn each regressor in the cascade. A novel data augmentation approach is proposed to improve the regressors performance by generating synthetic training data. The proposed optic cup and disc segmentation method is applied on an image set of 50 patients and demonstrate high segmentation accuracy for optic cup and disc with dice metric of 0.95 and 0.85 respectively. Comparative study shows that our proposed method outperforms state of the art optic cup and disc segmentation methods.
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Apparatus and method for measurement of the mechanical properties and electromigration of thin films
Maris, Humphrey J.
2001-01-01
A method for characterizing a sample comprising the steps of depositing the sample on a substrate, measuring a first change in optical response of the sample, changing the lateral strain of the sample, measuring a second change in optical response of the sample, comparing the second change in optical response of with the first change in optical response and associating a difference between the second change and the first change in optical response with a property of interest in the sample. The measurement of the first change in optical response is made with the sample having an initial lateral strain. The measurement of the second change in optical response is made after the lateral strain in the sample is changed from the initial lateral strain to a different lateral strain. The second change in optical response is compared to the first change in optical response to find the difference between the second change and the first change.
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Apparatus and method for measurement of the mechanical properties and electromigration of thin films
Maris, Humphrey J.
2000-01-01
A method for characterizing a sample comprising the steps of depositing the sample on a substrate, measuring a first change in optical response of the sample, changing the lateral strain of the sample, measuring a second change in optical response of the sample, comparing the second change in optical response of with the first change in optical response and associating a difference between the second change and the first change in optical response with a property of interest in the sample. The measurement of the first change in optical response is made with the sample having an initial lateral strain. The measurement of the second change in optical response is made after the lateral strain in the sample is changed from the initial lateral strain to a different lateral strain. The second change in optical response is compared to the first change in optical response to find the difference between the second change and the first change.
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NASA Astrophysics Data System (ADS)
Khosla, Ajit
2017-04-01
This talk focuses on preparation, characterization and micropatterning of electrically conducting KETJENBLACK carbon black nanoparticle (80 nm-diameter) doped Polydimethylsiloxane (PDMS) by employing extrusion mixing. Previously, we had reported fabrication of various micropatternable nanocomposites for wearable sensing applications vis solvent assisted ultrasonic mixing technique[1-16] . Extrusion mixing has an advantage as no organic solvents are used and homogenous dispersion of carbon nanoparticles is observed, which is confirmed by SEM analysis. The developed nanocomposite can be micropatterened using standard microfabrication techniques. It is also observed that percolation threshold occurs at 0.51 wt% of carbon nanoparticles in polymer matrix. Examples of developed nano-composites for wearable sensing applications for precision medicine will also be discussed. References: 1.http://summit.sfu.ca/item/12017 A. Khosla. Micropatternable multifunctional nanocomposite polymers for flexible soft MEMS applications. Diss. Applied Science: School of Engineering Science, 2011. 2. A. Khosla ; B. L. Gray; Fabrication of multiwalled carbon nanotube polydimethylsiloxne nanocomposite polymer flexible microelectrodes for microfluidics and MEMS. Proc. SPIE 7642, Electroactive Polymer Actuators and Devices (EAPAD) 2010, 76421V (April 09, 2010); doi:10.1117/12.847292. 3. Ang Li ; Ajit Khosla ; Connie Drewbrook ; Bonnie L. Gray; Fabrication and testing of thermally responsive hydrogel-based actuators using polymer heater elements for flexible microvalves. Proc. SPIE 7929, Microfluidics, BioMEMS, and Medical Microsystems IX, 79290G (February 14, 2011); doi:10.1117/12.873197. 4. Khosla, A. and Gray, B. L. (2010), Preparation, Micro-Patterning and Electrical Characterization of Functionalized Carbon-Nanotube Polydimethylsiloxane Nanocomposite Polymer. Macromol. Symp., 297: 210-218. doi:10.1002/masy.200900165 5. A. Khosla ; D. Hilbich ; C. Drewbrook ; D. Chung ; B. L. Gray; Large scale micropatterning of multi-walled carbon nanotube/polydimethylsiloxane nanocomposite polymer on highly flexible 12×24 inch substrates. Proc. SPIE 7926, Micromachining and Microfabrication Process Technology XVI, 79260L (February 15, 2011); doi:10.1117/12.876738. 6. A. Khosla, and Bonnie L. Gray. "(Invited) Micropatternable Multifunctional Nanocomposite Polymers for Flexible Soft NEMS and MEMS Applications." ECS Transactions 45.3 (2012): 477-494. doi: 10.1149/1.3700913 7. Khosla, Ajit. "Nanoparticle-doped electrically-conducting polymers for flexible nano-micro Systems." Electrochemical Society Interface 21.3-4 (2012): 67-70. 8. Ajit Khosla; Smart garments in chronic disease management: progress and challenges. Proc. SPIE 8548, Nanosystems in Engineering and Medicine, 85482O (October 24, 2012); doi:10.1117/12.979667. 9. D. Chung ; A. Khosla ; B. L. Gray; Screen printable flexible conductive nanocomposite polymer with applications to wearable sensors. Proc. SPIE 9060, Nanosensors, Biosensors, and Info-Tech Sensors and Systems 2014, 90600U (April 16, 2014); doi:10.1117/12.2046548. 10. Daehan Chung ; Sam Seyfollahi ; Ajit Khosla ; Bonnie Gray ; Ash Parameswaran ; Ramani Ramaseshan ; Kirpal Kohli; Initial experiments with flexible conductive electrodes for potential applications in cancer tissue screening. Proc. SPIE 7929, Microfluidics, BioMEMS, and Medical Microsystems IX, 79290Z (February 14, 2011); doi:10.1117/12.875563. 11. A. Khosla ; B. L. Gray; New technologies for large-scale micropatterning of functional nanocomposite polymers. Proc. SPIE 8344, Nanosensors, Biosensors, and Info-Tech Sensors and Systems 2012, 83440W (April 26, 2012); doi:10.1117/12.915178. 12. A. Khosla, B.L. Gray, Preparation, characterization and micromolding of multi-walled carbon nanotube polydimethylsiloxane conducting nanocomposite polymer, Materials Letters, Volume 63, Issues 13-14, 31 May 2009, Pages 1203-1206, ISSN 0167-577X, http://dx.doi.org/10.1016/j.matlet.2009.02.043. 13. Giassa, M., Khosla, A., Gray, B. et al. J Electron Test (2010) 26: 139. doi:10.1007/s10836-009-5125-3 14.Ozhikandathil, Jayan, Ajit Khosla, and Muthukumaran Packirisamy. "Electrically Conducting PDMS Nanocomposite Using In Situ Reduction of Gold Nanostructures and Mechanical Stimulation of Carbon Nanotubes and Silver Nanoparticles." ECS Journal of Solid State Science and Technology 4.10 (2015): S3048-S3052. doi:10.1149/2.0091510jss 15. Kassegne, Sam, Maria Vomero, Roberto Gavuglio, Mieko Hirabayashi, Emre Özyilmaz, Sebastien Nguyen, Jesus Rodriguez, Eda Özyilmaz, Pieter van Niekerk, and Ajit Khosla. "Electrical impedance, electrochemistry, mechanical stiffness, and hardness tunability in glassy carbon MEMS μECoG electrodes." Microelectronic Engineering 133 (2015): 36-44. 16. A. Khosla ; B. L. Gray; Fabrication and properties of conductive micromoldable thermosetting polymer for electronic routing in highly flexible microfluidic systems. Proc. SPIE 7593, Microfluidics, BioMEMS, and Medical Microsystems VIII, 759314 (February 17, 2010); doi:10.1117/12.840911.
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NASA Astrophysics Data System (ADS)
Palmer, Matthew E.; Slusher, David; Fielder, Robert S.
2006-01-01
In this paper, recent work on the performance of optical fiber, fiber optic sensors, and fiber optic connectors under the influence of a high-energy electron beam is presented. Electron beam irradiation is relevant for the Jupiter Icy Moons Orbiter (JIMO) mission due to the high electron radiation environment surrounding Jupiter. As an initial feasibility test, selected optical fiber components were exposed to dose levels relevant to the Jupiter environment. Three separate fiber types were used: one series consisted of pure silica core fiber, two other series consisted of different levels of Germania-doped fiber. Additionally, a series of fused silica Extrinsic Fabry-Perot Interferometer (EFPI)-based fiber optic sensors and two different types of fiber optic connectors were tested. Two types of fiber coatings were evaluated: acrylate and polyimide. All samples were exposed to three different dose levels: 2 MRad, 20 MRad, and 50 MRad. Optical loss measurements were made on the optical fiber spools as a function of wavelength between 750 and 1750nm at periodic intervals up to 75 hrs after exposure. Attenuation is minimal and wavelength-dependent. Fiber optic sensors were evaluated using a standard EFPI sensor readout and diagnostic system. Optical connectors and optical fiber coatings were visually inspected for degradation. Additionally, tensile testing and minimum bend radius testing was conducted on the fibers. Initial loss measurements indicate a low-level of induced optical attenuation in the fiber which recovers with time. The fiber optic sensors exhibited no observable degradation after exposure. The optical fiber connectors and coatings also showed no observable degradation. In addition to harsh environment survivability, fiber optic sensors offer a number of intrinsic advantages for space nuclear power applications including extremely low mass, immunity to electromagnetic interference, self diagnostics / prognostics, and smart sensor capability. Deploying fiber optic sensors on future space exploration missions would provide a substantial improvement in spacecraft instrumentation.
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Design, fabrication and testing of an optical temperature sensor
NASA Technical Reports Server (NTRS)
Morey, W. W.; Glenn, W. H.; Decker, R. O.; Mcclurg, W. C.
1980-01-01
The laboratory breadboard optical temperature sensor based on the temperature dependent absorptive characteristics of a rare earth (europium) doped optical fiber. The principles of operation, materials characterization, fiber and optical component design, design and fabrication of an electrooptic interface unit, signal processing, and initial test results are discussed. Initial tests indicated that, after a brief warmup period, the output of the sensor was stable to approximately 1 C at room temperature or approximately + or - 0.3 percent of point (K). This exceeds the goal of 1 percent of point. Recommendations are presented for further performance improvement.
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Discretely Self-Similar Solutions to the Navier-Stokes Equations with Besov Space Data
NASA Astrophysics Data System (ADS)
Bradshaw, Zachary; Tsai, Tai-Peng
2018-07-01
We construct self-similar solutions to the three dimensional Navier-Stokes equations for divergence free, self-similar initial data that can be large in the critical Besov space \\dot{B}_{p,∞}^{3/p-1} where 3 < p < 6. We also construct discretely self-similar solutions for divergence free initial data in \\dot{B}_{p,∞}^{3/p-1} for 3 < p < 6 that is discretely self-similar for some scaling factor λ > 1. These results extend those of Bradshaw and Tsai (Ann Henri Poincaré 2016. https://doi.org/10.1007/s00023-016-0519-0) which dealt with initial data in L 3 w since {L^3_w\\subsetneq \\dot{B}_{p,∞}^{3/p-1}} for p > 3. We also provide several concrete examples of vector fields in the relevant function spaces.
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44 CFR 206.348 - Consultation.
Code of Federal Regulations, 2010 CFR
2010-10-01
... designated representative of the Department of the Interior (DOI) at the regional level before approving any.... (a) The consultation shall be by written memorandum to the DOI representative and shall contain the... understanding with DOI, the DOI representative will provide technical information and an opinion whether or not...
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44 CFR 206.348 - Consultation.
Code of Federal Regulations, 2011 CFR
2011-10-01
... designated representative of the Department of the Interior (DOI) at the regional level before approving any.... (a) The consultation shall be by written memorandum to the DOI representative and shall contain the... understanding with DOI, the DOI representative will provide technical information and an opinion whether or not...
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NASA Astrophysics Data System (ADS)
Ding, Si-Jing; Nan, Fan; Yang, Da-Jie; Zhong, Yu-Ting; Hao, Zhong-Hua; Wang, Qu-Quan
2015-09-01
We investigate tunable plasmon resonance and enhanced second harmonic generation (SHG) and up-converted fluorescence (UCF) of the hemispheric-like silver core/shell islands. The Ag, Ag/Ag2O, and Ag/Ag2O/Ag island films are prepared by using a sputtering technique. The SHG and UCF of the Ag/Ag2O/Ag core/shell islands near the percolating regime is enhanced 2.34 and 3.94 times compared to the sum of two individual counterparts of Ag/Ag2O core/shell and Ag shell islands. The ratio of SHG intensity induced by p- and s-polarization is 0.86 for the initial Ag islands and increase to 1.61 for the Ag/Ag2O/Ag core/shell samples. The tunable intensity ratio of SHG to UCF of the Ag islands treated by thermal and laser annealing processes is also observed. The physical mechanism of the enhanced SHG and UCF in the Ag/Ag2O/Ag core/shell islands is discussed. Our observations provide a new approach to fabricate plasmon-enhanced optical nonlinear nanodevices with tunable SHG and UCF.We investigate tunable plasmon resonance and enhanced second harmonic generation (SHG) and up-converted fluorescence (UCF) of the hemispheric-like silver core/shell islands. The Ag, Ag/Ag2O, and Ag/Ag2O/Ag island films are prepared by using a sputtering technique. The SHG and UCF of the Ag/Ag2O/Ag core/shell islands near the percolating regime is enhanced 2.34 and 3.94 times compared to the sum of two individual counterparts of Ag/Ag2O core/shell and Ag shell islands. The ratio of SHG intensity induced by p- and s-polarization is 0.86 for the initial Ag islands and increase to 1.61 for the Ag/Ag2O/Ag core/shell samples. The tunable intensity ratio of SHG to UCF of the Ag islands treated by thermal and laser annealing processes is also observed. The physical mechanism of the enhanced SHG and UCF in the Ag/Ag2O/Ag core/shell islands is discussed. Our observations provide a new approach to fabricate plasmon-enhanced optical nonlinear nanodevices with tunable SHG and UCF. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr03627e
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Implementing DOIs for Oceanographic Satellite Data at PO.DAAC
NASA Astrophysics Data System (ADS)
Hausman, J.; Tauer, E.; Chung, N.; Chen, C.; Moroni, D. F.
2013-12-01
The Physical Oceanographic Distributed Active Archive Center (PO.DAAC) is NASA's archive for physical oceanographic satellite data. It distributes over 500 datasets from gravity, ocean wind, sea surface topography, sea ice, ocean currents, salinity, and sea surface temperature satellite missions. A dataset is a collection of granules/files that share the same mission/project, versioning, processing level, spatial, and temporal characteristics. The large number of datasets is partially due to the number of satellite missions, but mostly because a single satellite mission typically has multiple versions or even temporal and spatial resolutions of data. As a result, a user might mistake one dataset for a different dataset from the same satellite mission. Due to the PO.DAAC'S vast variety and volume of data and growing requirements to report dataset usage, it has begun implementing DOIs for the datasets it archives and distributes. However, this was not as simple as registering a name for a DOI and providing a URL. Before implementing DOIs multiple questions needed to be answered. What are the sponsor and end-user expectations regarding DOIs? At what level does a DOI get assigned (dataset, file/granule)? Do all data get a DOI, or only selected data? How do we create a DOI? How do we create landing pages and manage them? What changes need to be made to the data archive, life cycle policy and web portal to accommodate DOIs? What if the data also exists at another archive and a DOI already exists? How is a DOI included if the data were obtained via a subsetting tool? How does a researcher or author provide a unique, definitive reference (standard citation) for a given dataset? This presentation will discuss how these questions were answered through changes in policy, process, and system design. Implementing DOIs is not a trivial undertaking, but as DOIs are rapidly becoming the de facto approach, it is worth the effort. Researchers have historically referenced the source satellite and data center (or archive), but scientific writings do not typically provide enough detail to point to a singular, uniquely identifiable dataset. DOIs provide the means to help researchers be precise in their data citations and provide needed clarity, standardization and permanence.
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Maggio, Lauren A; Willinsky, John M; Steinberg, Ryan M; Mietchen, Daniel; Wass, Joseph L; Dong, Ting
2017-01-01
Wikipedia is a gateway to knowledge. However, the extent to which this gateway ends at Wikipedia or continues via supporting citations is unknown. Wikipedia's gateway functionality has implications for information design and education, notably in medicine. This study aims to establish benchmarks for the relative distribution and referral (click) rate of citations-as indicated by presence of a Digital Object Identifier (DOI)-from Wikipedia, with a focus on medical citations. DOIs referred from the English Wikipedia in August 2016 were obtained from Crossref.org. Next, based on a DOI's presence on a WikiProject Medicine page, all DOIs in Wikipedia were categorized as medical (WP:MED) or non-medical (non-WP:MED). Using this categorization, referred DOIs were classified as WP:MED, non-WP:MED, or BOTH, meaning the DOI may have been referred from either category. Data were analyzed using descriptive and inferential statistics. Out of 5.2 million Wikipedia pages, 4.42% (n = 229,857) included at least one DOI. 68,870 were identified as WP:MED, with 22.14% (n = 15,250) featuring one or more DOIs. WP:MED pages featured on average 8.88 DOI citations per page, whereas non-WP:MED pages had on average 4.28 DOI citations. For DOIs only on WP:MED pages, a DOI was referred every 2,283 pageviews and for non-WP:MED pages every 2,467 pageviews. DOIs from BOTH pages accounted for 12% (n = 58,475). The referral of DOI citations found in BOTH could not be assigned to WP:MED or non-WP:MED, as the page from which the referral was made was not provided with the data. While these results cannot provide evidence of greater citation referral from WP:MED than non-WP:MED, they do provide benchmarks to assess strategies for changing referral patterns. These changes might include editors adopting new methods for designing and presenting citations or the introduction of teaching strategies that address the value of consulting citations as a tool for extending learning.
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A review of optical pacing with infrared light
NASA Astrophysics Data System (ADS)
Ford, S. M.; Watanabe, M.; Jenkins, M. W.
2018-02-01
Optical pacing (OP) uses pulsed infrared light to initiate heartbeats in electrically excitable cardiac tissues without employing exogenous agents. OP is an alternative approach to electrical pacing that may overcome some its disadvantages for some applications. In this review, we discuss the initial demonstrations, mechanisms, safety, advantages and applications of OP.
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Space and frequency-multiplexed optical linear algebra processor - Fabrication and initial tests
NASA Technical Reports Server (NTRS)
Casasent, D.; Jackson, J.
1986-01-01
A new optical linear algebra processor architecture is described. Space and frequency-multiplexing are used to accommodate bipolar and complex-valued data. A fabricated laboratory version of this processor is described, the electronic support system used is discussed, and initial test data obtained on it are presented.
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Ground state initialization in a doubly-charged, vertically-stacked InAs quantum dot molecule
NASA Astrophysics Data System (ADS)
Ross, Aaron; Chow, Colin; Sham, Lu; Bracker, Allan; Gammon, Daniel; Steel, Duncan
2015-03-01
We report on the rapid optical initialization of a subset of the two-electron ground states of a self-assembled, vertically stacked InAs quantum dot molecule, where the states of the electron are approximately localized to separate quantum dots with very little spatial overlap. Four eigenstates, a singlet and three triplets (S,T0,T+, T-) , arise from the exchange coupling and are identified via bias-dependent photoluminescence measurements. The degeneracy of the triplet states is lifted using an in-plane magnetic field (Voigt geometry). This allows for the determination of the in-plane electron and hole g-factors using differential transmission measurements in the co-tunneling regime (to avoid optical pumping). Three of the four eigenstates (S,T+, T-) can then be initialized with high fidelity using continuous wave (CW) optical pumping. Optical transition degeneracies prohibit simple CW initialization of the T0 state. Efforts towards near-unity initialization of the T0 state via two-photon Raman transitions will be presented. This work represents the first step in demonstrating a two-qubit quantum register based on electron spins in self-assembled quantum dots. This work is supported by NSF, ARO, AFSOR, DARPA, and ONR.
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Code of Federal Regulations, 2011 CFR
2011-10-01
..., and Enforcement Procedures § 17.332 Mediation. (a) Referral of complaints for mediation. DOI will... it. The FMCS shall send the agreement to DOI. DOI, however, retains the right to monitor the... process without prior approval of the head of the mediation agency. (e) DOI will use the mediation process...
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43 CFR 17.314 - Age distinctions contained in DOI regulations.
Code of Federal Regulations, 2011 CFR
2011-10-01
... 43 Public Lands: Interior 1 2011-10-01 2011-10-01 false Age distinctions contained in DOI... Age Standards for Determining Age Discrimination § 17.314 Age distinctions contained in DOI regulations. Any age distinctions contained in a rule or regulation issued by DOI shall be presumed to be...
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43 CFR 17.314 - Age distinctions contained in DOI regulations.
Code of Federal Regulations, 2013 CFR
2013-10-01
... 43 Public Lands: Interior 1 2013-10-01 2013-10-01 false Age distinctions contained in DOI... Age Standards for Determining Age Discrimination § 17.314 Age distinctions contained in DOI regulations. Any age distinctions contained in a rule or regulation issued by DOI shall be presumed to be...
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43 CFR 17.314 - Age distinctions contained in DOI regulations.
Code of Federal Regulations, 2014 CFR
2014-10-01
... 43 Public Lands: Interior 1 2014-10-01 2014-10-01 false Age distinctions contained in DOI... Age Standards for Determining Age Discrimination § 17.314 Age distinctions contained in DOI regulations. Any age distinctions contained in a rule or regulation issued by DOI shall be presumed to be...
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43 CFR 17.314 - Age distinctions contained in DOI regulations.
Code of Federal Regulations, 2012 CFR
2012-10-01
... 43 Public Lands: Interior 1 2012-10-01 2011-10-01 true Age distinctions contained in DOI... Age Standards for Determining Age Discrimination § 17.314 Age distinctions contained in DOI regulations. Any age distinctions contained in a rule or regulation issued by DOI shall be presumed to be...
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43 CFR 17.320 - General responsibilities.
Code of Federal Regulations, 2010 CFR
2010-10-01
... ASSISTED PROGRAMS OF THE DEPARTMENT OF THE INTERIOR Nondiscrimination on the Basis of Age Duties of Doi Recipients § 17.320 General responsibilities. Each DOI recipient has primary responsibility to ensure that... information, and to afford DOI access to its records to the extent DOI finds necessary to determine whether...
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30 CFR 250.1001 - Definitions.
Code of Federal Regulations, 2010 CFR
2010-07-01
... used in this subpart shall have the meanings given below: DOI pipelines include: (1) Producer-operated...) Transporter-operated pipelines that DOI and DOT have agreed are to be regulated as DOI pipelines; and (5) All..., maintenance, and operation; (2) Producer-operated pipelines that DOI and DOT have agreed are to be regulated...
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43 CFR 17.314 - Age distinctions contained in DOI regulations.
Code of Federal Regulations, 2010 CFR
2010-10-01
... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Age distinctions contained in DOI... Age Standards for Determining Age Discrimination § 17.314 Age distinctions contained in DOI regulations. Any age distinctions contained in a rule or regulation issued by DOI shall be presumed to be...
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Code of Federal Regulations, 2010 CFR
2010-10-01
... or on behalf of others, may file a complaint with DOI, alleging discrimination prohibited by the Act... good cause shown, however, DOI may extend this time limit. (b) DOI will consider the date a complaint... described in paragraphs (a) and (c)(1) of this section. (c) DOI will attempt to facilitate the filing of...
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43 CFR 17.320 - General responsibilities.
Code of Federal Regulations, 2011 CFR
2011-10-01
... ASSISTED PROGRAMS OF THE DEPARTMENT OF THE INTERIOR Nondiscrimination on the Basis of Age Duties of Doi Recipients § 17.320 General responsibilities. Each DOI recipient has primary responsibility to ensure that... information, and to afford DOI access to its records to the extent DOI finds necessary to determine whether...
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Code of Federal Regulations, 2011 CFR
2011-10-01
... or on behalf of others, may file a complaint with DOI, alleging discrimination prohibited by the Act... good cause shown, however, DOI may extend this time limit. (b) DOI will consider the date a complaint... described in paragraphs (a) and (c)(1) of this section. (c) DOI will attempt to facilitate the filing of...
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Code of Federal Regulations, 2011 CFR
2011-07-01
... which are related to NPSL operations shall be subject to audit by DOI or its appointed agent. Where possible, the auditor for DOI shall coordinate audit efforts with other nonoperators, if any. DOI shall... the same manner as the operator is notified. DOI may elect to send an auditor with the audit team...
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A Secular Variation Model for Igrf-12 Based on Swarm Data and Inverse Geodynamo Modelling
NASA Astrophysics Data System (ADS)
Fournier, A.; Aubert, J.; Erwan, T.
2014-12-01
We are proposing a secular variation candidate model for the 12th generation of the international geomagnetic reference field, spanning the years 2015-2020. The novelty of our approach stands in the initialization of a 5-yr long integration of a numerical model of Earth's dynamo by means of inverse geodynamo modelling, as introduced by Aubert (GJI, 2014). This inverse technique combines the information coming from the observations (in the form of an instantaneous estimate of the Gauss coefficients for the magnetic field and its secular variation) with that coming from the multivariate statistics of a free run of a numerical model of the geodynamo. The Gauss coefficients and their error covariance properties are determined from Swarm data along the lines detailed by Thébault et al. (EPS, 2010). The numerical model of the geodynamo is the so-called Coupled Earth Dynamo model (Aubert et al., Nature, 2013), whose variability possesses a strong level of similarity with that of the geomagnetic field. We illustrate and assess the potential of this methodology by applying it to recent time intervals, with an initialization based on CHAMP data, and conclude by presenting our SV candidate, whose initialization is based on the 1st year of Swarm data This work is supported by the French "Agence Nationale de la Recherche" under the grant ANR-11-BS56-011 (http://avsgeomag.ipgp.fr) and by the CNES. References: Aubert, J., Geophys. J. Int. 197, 1321-1334, 2014, doi: 10.1093/gji/ggu064 Aubert, J., Finlay, C., Fournier, F. Nature 502, 219-223, 2013, doi: 10.1038/nature12574 Thébault E. , A. Chulliat, S. Maus, G. Hulot, B. Langais, A. Chambodut and M. Menvielle, Earth Planets Space, Vol. 62 (No. 10), pp. 753-763, 2010.
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Solving the Sea-Level Equation in an Explicit Time Differencing Scheme
NASA Astrophysics Data System (ADS)
Klemann, V.; Hagedoorn, J. M.; Thomas, M.
2016-12-01
In preparation of coupling the solid-earth to an ice-sheet compartment in an earth-system model, the dependency of initial topography on the ice-sheet history and viscosity structure has to be analysed. In this study, we discuss this dependency and how it influences the reconstruction of former sea level during a glacial cycle. The modelling is based on the VILMA code in which the field equations are solved in the time domain applying an explicit time-differencing scheme. The sea-level equation is solved simultaneously in the same explicit scheme as the viscoleastic field equations (Hagedoorn et al., 2007). With the assumption of only small changes, we neglect the iterative solution at each time step as suggested by e.g. Kendall et al. (2005). Nevertheless, the prediction of the initial paleo topography in case of moving coastlines remains to be iterated by repeated integration of the whole load history. The sensitivity study sketched at the beginning is accordingly motivated by the question if the iteration of the paleo topography can be replaced by a predefined one. This study is part of the German paleoclimate modelling initiative PalMod. Lit:Hagedoorn JM, Wolf D, Martinec Z, 2007. An estimate of global mean sea-level rise inferred from tide-gauge measurements using glacial-isostatic models consistent with the relative sea-level record. Pure appl. Geophys. 164: 791-818, doi:10.1007/s00024-007-0186-7Kendall RA, Mitrovica JX, Milne GA, 2005. On post-glacial sea level - II. Numerical formulation and comparative reesults on spherically symmetric models. Geophys. J. Int., 161: 679-706, doi:10.1111/j.365-246.X.2005.02553.x
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Impact of initial pulse shape on the nonlinear spectral compression in optical fibre
NASA Astrophysics Data System (ADS)
Boscolo, Sonia; Chaussard, Frederic; Andresen, Esben; Rigneault, Hervé; Finot, Christophe
2018-02-01
We theoretically study the effects of the temporal intensity profile of the initial pulse on the nonlinear propagation spectral compression process arising from nonlinear propagation in an optical fibre. Various linearly chirped input pulse profiles are considered, and their dynamics is explained with the aid of time-frequency representations. While initially parabolic-shaped pulses show enhanced spectral compression compared to Gaussian pulses, no significant spectral narrowing occurs when initially super-Gaussian pulses are used. Triangular pulses lead to a spectral interference phenomenon similar to the Fresnel bi-prism experiment.
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Tolyporphin-An Unusual Green Chlorin-like Dioxobacteriochlorin.
Brückner, Christian
2017-10-01
The tolyporphins, a family of green tetrapyrrolic pigments isolated from a cyanobacterium-microbial ecological unit, possess unique carbohydrate-derivatized dioxobacteriochlorin frameworks. A brief overview over the history, synthesis, chemistry and biological properties of the tolyporphins forms the backdrop for highlighting the contribution by Hood et al. (Photochem. Photobiol., 2017, https://doi.org/10.1111/php.12781) who demonstrate the optical properties of tolyporphins to be more similar to those of chlorins than of bacteriochlorins. This property could be correlated with the presence of β-oxo-functionalities. The study continues to clarify the structure, properties and possible roles of these intriguing chromophores with a range of biomedical properties. © 2017 The American Society of Photobiology.
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Volcanic stratospheric sulfur injections and aerosol optical depth from 500 BCE to 1900 CE
NASA Astrophysics Data System (ADS)
Toohey, Matthew; Sigl, Michael
2017-11-01
The injection of sulfur into the stratosphere by explosive volcanic eruptions is the cause of significant climate variability. Based on sulfate records from a suite of ice cores from Greenland and Antarctica, the eVolv2k database includes estimates of the magnitudes and approximate source latitudes of major volcanic stratospheric sulfur injection (VSSI) events from 500 BCE to 1900 CE, constituting an update of prior reconstructions and an extension of the record by 1000 years. The database incorporates improvements to the ice core records (in terms of synchronisation and dating) and refinements to the methods used to estimate VSSI from ice core records, and it includes first estimates of the random uncertainties in VSSI values. VSSI estimates for many of the largest eruptions, including Samalas (1257), Tambora (1815), and Laki (1783), are within 10 % of prior estimates. A number of strong events are included in eVolv2k which are largely underestimated or not included in earlier VSSI reconstructions, including events in 540, 574, 682, and 1108 CE. The long-term annual mean VSSI from major volcanic eruptions is estimated to be ˜ 0.5 Tg [S] yr-1, ˜ 50 % greater than a prior reconstruction due to the identification of more events and an increase in the magnitude of many intermediate events. A long-term latitudinally and monthly resolved stratospheric aerosol optical depth (SAOD) time series is reconstructed from the eVolv2k VSSI estimates, and the resulting global mean SAOD is found to be similar (within 33 %) to a prior reconstruction for most of the largest eruptions. The long-term (500 BCE-1900 CE) average global mean SAOD estimated from the eVolv2k VSSI estimates including a constant background injection of stratospheric sulfur is ˜ 0.014, 30 % greater than a prior reconstruction. These new long-term reconstructions of past VSSI and SAOD variability give context to recent volcanic forcing, suggesting that the 20th century was a period of somewhat weaker than average volcanic forcing, with current best estimates of 20th century mean VSSI and SAOD values being 25 and 14 % less, respectively, than the mean of the 500 BCE to 1900 CE period. The reconstructed VSSI and SAOD data are available at https://doi.org/10.1594/WDCC/eVolv2k_v2.
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A global space-based stratospheric aerosol climatology: 1979-2016
NASA Astrophysics Data System (ADS)
Thomason, Larry W.; Ernest, Nicholas; Millán, Luis; Rieger, Landon; Bourassa, Adam; Vernier, Jean-Paul; Manney, Gloria; Luo, Beiping; Arfeuille, Florian; Peter, Thomas
2018-03-01
We describe the construction of a continuous 38-year record of stratospheric aerosol optical properties. The Global Space-based Stratospheric Aerosol Climatology, or GloSSAC, provided the input data to the construction of the Climate Model Intercomparison Project stratospheric aerosol forcing data set (1979-2014) and we have extended it through 2016 following an identical process. GloSSAC focuses on the Stratospheric Aerosol and Gas Experiment (SAGE) series of instruments through mid-2005, and on the Optical Spectrograph and InfraRed Imager System (OSIRIS) and the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) data thereafter. We also use data from other space instruments and from ground-based, air, and balloon borne instruments to fill in key gaps in the data set. The end result is a global and gap-free data set focused on aerosol extinction coefficient at 525 and 1020 nm and other parameters on an "as available" basis. For the primary data sets, we developed a new method for filling the post-Pinatubo eruption data gap for 1991-1993 based on data from the Cryogenic Limb Array Etalon Spectrometer. In addition, we developed a new method for populating wintertime high latitudes during the SAGE period employing a latitude-equivalent latitude conversion process that greatly improves the depiction of aerosol at high latitudes compared to earlier similar efforts. We report data in the troposphere only when and where it is available. This is primarily during the SAGE II period except for the most enhanced part of the Pinatubo period. It is likely that the upper troposphere during Pinatubo was greatly enhanced over non-volcanic periods and that domain remains substantially under-characterized. We note that aerosol levels during the OSIRIS/CALIPSO period in the lower stratosphere at mid- and high latitudes is routinely higher than what we observed during the SAGE II period. While this period had nearly continuous low-level volcanic activity, it is possible that the enhancement in part reflects deficiencies in the data set. We also expended substantial effort to quality assess the data set and the product is by far the best we have produced. GloSSAC version 1.0 is available in netCDF format at the NASA Atmospheric Data Center at https://eosweb.larc.nasa.gov/. GloSSAC users should cite this paper and the data set DOI (https://doi.org/10.5067/GloSSAC-L3-V1.0).
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Effects of Early Acute Care on Autonomic Outcomes in SCI: Bedside to Bench and Back
2015-10-01
fractures in the US military. Spine J. 2012;12(9):777–83. [PMID:21393068] http://dx.doi.org/10.1016/j.spinee.2011.01.029 3. Macciocchi S, Seel RT...47. Dai, L.Y., Wang, X.Y. and Jiang, L.S. (2007). Neurologic recovery from thoracolumbar burst fractures : is it predicted by the amount of initial...patients (15%) also presented with a concurrent traumatic brain injury. Additional complications and comorbidi- ties included 1 pulmonary embolism without
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NASA's Big Earth Data Initiative Accomplishments
NASA Technical Reports Server (NTRS)
Klene, Stephan A.; Pauli, Elisheva; Pressley, Natalie N.; Cechini, Matthew F.; McInerney, Mark
2017-01-01
The goal of NASA's effort for BEDI is to improve the usability, discoverability, and accessibility of Earth Observation data in support of societal benefit areas. Accomplishments: In support of BEDI goals, datasets have been entered into Common Metadata Repository(CMR), made available via the Open-source Project for a Network Data Access Protocol (OPeNDAP), have a Digital Object Identifier (DOI) registered for the dataset, and to support fast visualization many layers have been added in to the Global Imagery Browse Services (GIBS).
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NASA's Big Earth Data Initiative Accomplishments
NASA Astrophysics Data System (ADS)
Klene, S. A.; Pauli, E.; Pressley, N. N.; Cechini, M. F.; McInerney, M.
2017-12-01
The goal of NASA's effort for BEDI is to improve the usability, discoverability, and accessibility of Earth Observation data in support of societal benefit areas. Accomplishments: In support of BEDI goals, datasets have been entered into Common Metadata Repository(CMR), made available via the Open-source Project for a Network Data Access Protocol (OPeNDAP), have a Digital Object Identifier (DOI) registered for the dataset, and to support fast visualization many layers have been added in to the Global Imagery Browse Service(GIBS)
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Mixing, Combustion, and Other Interface Dominated Flows; Paragraphs 3.2.1 A, B, C and 3.2.2 A
2014-04-09
Condensed Matter Physics , (12 2010): 43401. doi: H. Lim, Y. Yu, J. Glimm, X. L. Li, D.H. Sharp. Subgrid Models for Mass and Thermal Diffusion in...zone and a series of radial cracks in solid plates hit by high velocity projectiles). • Only 2D dimensional models • Serial codes for running on single ...exter- nal parallel packages TAO and Global Arrays, developed within DOE high performance computing initiatives. A Schwartz-type overlapping domain
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Nonlinear waves in earth crust faults: application to regular and slow earthquakes
NASA Astrophysics Data System (ADS)
Gershenzon, Naum; Bambakidis, Gust
2015-04-01
The genesis, development and cessation of regular earthquakes continue to be major problems of modern geophysics. How are earthquakes initiated? What factors determine the rapture velocity, slip velocity, rise time and geometry of rupture? How do accumulated stresses relax after the main shock? These and other questions still need to be answered. In addition, slow slip events have attracted much attention as an additional source for monitoring fault dynamics. Recently discovered phenomena such as deep non-volcanic tremor (NVT), low frequency earthquakes (LFE), very low frequency earthquakes (VLF), and episodic tremor and slip (ETS) have enhanced and complemented our knowledge of fault dynamic. At the same time, these phenomena give rise to new questions about their genesis, properties and relation to regular earthquakes. We have developed a model of macroscopic dry friction which efficiently describes laboratory frictional experiments [1], basic properties of regular earthquakes including post-seismic stress relaxation [3], the occurrence of ambient and triggered NVT [4], and ETS events [5, 6]. Here we will discuss the basics of the model and its geophysical applications. References [1] Gershenzon N.I. & G. Bambakidis (2013) Tribology International, 61, 11-18, http://dx.doi.org/10.1016/j.triboint.2012.11.025 [2] Gershenzon, N.I., G. Bambakidis and T. Skinner (2014) Lubricants 2014, 2, 1-x manuscripts; doi:10.3390/lubricants20x000x; arXiv:1411.1030v2 [3] Gershenzon N.I., Bykov V. G. and Bambakidis G., (2009) Physical Review E 79, 056601 [4] Gershenzon, N. I, G. Bambakidis, (2014a), Bull. Seismol. Soc. Am., 104, 4, doi: 10.1785/0120130234 [5] Gershenzon, N. I.,G. Bambakidis, E. Hauser, A. Ghosh, and K. C. Creager (2011), Geophys. Res. Lett., 38, L01309, doi:10.1029/2010GL045225. [6] Gershenzon, N.I. and G. Bambakidis (2014) Bull. Seismol. Soc. Am., (in press); arXiv:1411.1020
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NASA Astrophysics Data System (ADS)
Varghese, Babu; Bonito, Valentina; Turco, Simona; Verhagen, Rieko
2016-03-01
Laser induced optical breakdown (LIOB) is a non-linear absorption process leading to plasma formation at locations where the threshold irradiance for breakdown is surpassed. In this paper we experimentally demonstrate the influence of polarization and absorption on laser induced breakdown threshold in transparent, absorbing and scattering phantoms made from water suspensions of polystyrene microspheres. We demonstrate that radially polarized light yields a lower irradiance threshold for creating optical breakdown compared to linearly polarized light. We also demonstrate that the thermal initiation pathway used for generating seed electrons results in a lower irradiance threshold compared to multiphoton initiation pathway used for optical breakdown.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Menapace, J A; Penetrante, B; Golini, D
2001-11-01
Laser induced damage initiation on fused silica optics can limit the lifetime of the components when used in high power UV laser environments. Foe example in inertial confinement fusion research applications, the optics can be exposed to temporal laser pulses of about 3-nsec with average fluences of 8 J/cm{sup 2} and peak fluences between 12 and 15 J/cm{sup 2}. During the past year, we have focused on optimizing the damage performance at a wavelength of 355-nm (3{omega}), 3-nsec pulse length, for optics in this category by examining a variety of finishing technologies with a challenge to improve the laser damagemore » initiation density by at least two orders of magnitude. In this paper, we describe recent advances in improving the 3{omega} damage initiation performance of laboratory-scale zirconium oxide and cerium oxide conventionally finished fused silica optics via application of processes incorporating magnetorheological finishing (MRF), wet chemical etching, and UV laser conditioning. Details of the advanced finishing procedures are described and comparisons are made between the procedures based upon large area 3{omega} damage performance, polishing layer contamination, and optical subsurface damage.« less
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Federal Register 2010, 2011, 2012, 2013, 2014
2011-12-14
... statement'') after their dates of ineligibility (``DOI''). Candidates are required to submit a NOCO... notified of their DOI by the Commission. A Candidate who has net outstanding campaign obligations post-DOI... each matching fund request submitted after the candidate's DOI. These statements are due just before...
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Celada, Pau; Puig, M Victoria; Díaz-Mataix, Llorenç; Artigas, Francesc
2008-09-01
Perceptual and psychic alterations and thought disorder are fundamental elements of schizophrenia symptoms, a pathology associated with an abnormal macro- and microcircuitry of several brain areas including the prefrontal cortex (PFC). Alterations in information processing in PFC may partly underlie schizophrenia symptoms. The 5-HT(2A/2C) agonist DOI and antipsychotic drugs were administered to anesthetized rats. Single unit and local field potential (LFP) extracellular recordings were made in medial PFC (mPFC). Electrolytic lesions were performed in the thalamic nuclei. DOI markedly disrupts cellular and network activity in rat PFC. DOI altered pyramidal discharge in mPFC (39% excited, 27% inhibited, 34% unaffected; n = 51). In all instances, DOI concurrently reduced low-frequency oscillations (.3-4 Hz; power spectrum: .25 +/- .02 and .14 +/- .01 microV(2) in basal conditions and after 50-300 microg/kg intravenous (i.v.) DOI, respectively; n = 51). Moreover, DOI disrupted the temporal association between the active phase of LFP and pyramidal discharge. Both effects were reversed by M100907 (5-HT(2A) receptor antagonist) and were not attenuated by thalamic lesions, supporting an intracortical origin of the effects of DOI. The reduction in low-frequency oscillations induced by DOI was significantly reversed by the antipsychotic drugs haloperidol (.1-.2 mg/kg i.v.) and clozapine (1 mg/kg i.v.). DOI disorganizes network activity in PFC, reducing low-frequency oscillations and desynchronizing pyramidal discharge from active phases of LFP. These effects may underlie DOI's psychotomimetic action. The reversal by clozapine and haloperidol indicates that antipsychotic drugs may reduce psychotic symptoms by normalizing an altered PFC function.
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NASA Astrophysics Data System (ADS)
Lee, Min Sun; Kim, Kyeong Yun; Ko, Guen Bae; Lee, Jae Sung
2017-05-01
In this study, we developed a proof-of-concept prototype PET system using a pair of depth-of-interaction (DOI) PET detectors based on the proposed DOI-encoding method and digital silicon photomultiplier (dSiPM). Our novel cost-effective DOI measurement method is based on a triangular-shaped reflector that requires only a single-layer pixelated crystal and single-ended signal readout. The DOI detector consisted of an 18 × 18 array of unpolished LYSO crystal (1.47 × 1.47 × 15 mm3) wrapped with triangular-shaped reflectors. The DOI information was encoded by depth-dependent light distribution tailored by the reflector geometry and DOI correction was performed using four-step depth calibration data and maximum-likelihood (ML) estimation. The detector pair and the object were placed on two motorized rotation stages to demonstrate 12-block ring PET geometry with 11.15 cm diameter. Spatial resolution was measured and phantom and animal imaging studies were performed to investigate imaging performance. All images were reconstructed with and without the DOI correction to examine the impact of our DOI measurement. The pair of dSiPM-based DOI PET detectors showed good physical performances respectively: 2.82 and 3.09 peak-to-valley ratios, 14.30% and 18.95% energy resolution, and 4.28 and 4.24 mm DOI resolution averaged over all crystals and all depths. A sub-millimeter spatial resolution was achieved at the center of the field of view (FOV). After applying ML-based DOI correction, maximum 36.92% improvement was achieved in the radial spatial resolution and a uniform resolution was observed within 5 cm of transverse PET FOV. We successfully acquired phantom and animal images with improved spatial resolution and contrast by using the DOI measurement. The proposed DOI-encoding method was successfully demonstrated in the system level and exhibited good performance, showing its feasibility for animal PET applications with high spatial resolution and sensitivity.
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Willinsky, John M.; Steinberg, Ryan M.; Mietchen, Daniel; Wass, Joseph L.; Dong, Ting
2017-01-01
Wikipedia is a gateway to knowledge. However, the extent to which this gateway ends at Wikipedia or continues via supporting citations is unknown. Wikipedia’s gateway functionality has implications for information design and education, notably in medicine. This study aims to establish benchmarks for the relative distribution and referral (click) rate of citations—as indicated by presence of a Digital Object Identifier (DOI)—from Wikipedia, with a focus on medical citations. DOIs referred from the English Wikipedia in August 2016 were obtained from Crossref.org. Next, based on a DOI’s presence on a WikiProject Medicine page, all DOIs in Wikipedia were categorized as medical (WP:MED) or non-medical (non-WP:MED). Using this categorization, referred DOIs were classified as WP:MED, non-WP:MED, or BOTH, meaning the DOI may have been referred from either category. Data were analyzed using descriptive and inferential statistics. Out of 5.2 million Wikipedia pages, 4.42% (n = 229,857) included at least one DOI. 68,870 were identified as WP:MED, with 22.14% (n = 15,250) featuring one or more DOIs. WP:MED pages featured on average 8.88 DOI citations per page, whereas non-WP:MED pages had on average 4.28 DOI citations. For DOIs only on WP:MED pages, a DOI was referred every 2,283 pageviews and for non-WP:MED pages every 2,467 pageviews. DOIs from BOTH pages accounted for 12% (n = 58,475). The referral of DOI citations found in BOTH could not be assigned to WP:MED or non-WP:MED, as the page from which the referral was made was not provided with the data. While these results cannot provide evidence of greater citation referral from WP:MED than non-WP:MED, they do provide benchmarks to assess strategies for changing referral patterns. These changes might include editors adopting new methods for designing and presenting citations or the introduction of teaching strategies that address the value of consulting citations as a tool for extending learning. PMID:29267345
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Mismatch between the eye and the optic lobe in the giant squid.
Liu, Yung-Chieh; Liu, Tsung-Han; Yu, Chun-Chieh; Su, Chia-Hao; Chiao, Chuan-Chin
2017-07-01
Giant squids ( Architeuthis ) are a legendary species among the cephalopods. They live in the deep sea and are well known for their enormous body and giant eyes. It has been suggested that their giant eyes are not adapted for the detection of either mates or prey at distance, but rather are best suited for monitoring very large predators, such as sperm whales, at distances exceeding 120 m and at a depth below 600 m (Nilsson et al. 2012 Curr. Biol. 22 , 683-688. (doi:10.1016/j.cub.2012.02.031)). However, it is not clear how the brain of giant squids processes visual information. In this study, the optic lobe of a giant squid ( Architeuthis dux , male, mantle length 89 cm), which was caught by local fishermen off the northeastern coast of Taiwan, was scanned using high-resolution magnetic resonance imaging in order to examine its internal structure. It was evident that the volume ratio of the optic lobe to the eye in the giant squid is much smaller than that in the oval squid ( Sepioteuthis lessoniana ) and the cuttlefish ( Sepia pharaonis ). Furthermore, the cell density in the cortex of the optic lobe is significantly higher in the giant squid than in oval squids and cuttlefish, with the relative thickness of the cortex being much larger in Architeuthis optic lobe than in cuttlefish. This indicates that the relative size of the medulla of the optic lobe in the giant squid is disproportionally smaller compared with these two cephalopod species. This morphological study of the giant squid brain, though limited only to the optic lobe, provides the first evidence to support that the optic lobe cortex, the visual information processing area in cephalopods, is well developed in the giant squid. In comparison, the optic lobe medulla, the visuomotor integration centre in cephalopods, is much less developed in the giant squid than other species. This finding suggests that, despite the giant eye and a full-fledged cortex within the optic lobe, the brain of giant squids has not evolved proportionally in terms of performing complex tasks compared with shallow-water cephalopod species.
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Beck, Roy W; Trobe, Jonathan D; Moke, Pamela S; Gal, Robin L; Xing, Dongyuan; Bhatti, M Tariq; Brodsky, Michael C; Buckley, Edward G; Chrousos, Georgia A; Corbett, James; Eggenberger, Eric; Goodwin, James A; Katz, Barrett; Kaufman, David I; Keltner, John L; Kupersmith, Mark J; Miller, Neil R; Nazarian, Sarkis; Orengo-Nania, Silvia; Savino, Peter J; Shults, William T; Smith, Craig H; Wall, Michael
2003-07-01
To identify factors associated with a high and low risk of developing multiple sclerosis after an initial episode of optic neuritis. Three hundred eighty-eight patients who experienced acute optic neuritis between July 1, 1988, and June 30, 1991, were followed up prospectively for the development of multiple sclerosis. Consenting patients were reassessed after 10 to 13 years. The 10-year risk of multiple sclerosis was 38% (95% confidence interval, 33%-43%). Patients (160) who had 1 or more typical lesions on the baseline magnetic resonance imaging (MRI) scan of the brain had a 56% risk; those with no lesions (191) had a 22% risk (P<.001, log rank test). Among the patients who had no lesions on MRI, male gender and optic disc swelling were associated with a lower risk of multiple sclerosis, as was the presence of the following atypical features for optic neuritis: no light perception vision; absence of pain; and ophthalmoscopic findings of severe optic disc edema, peripapillary hemorrhages, or retinal exudates. The 10-year risk of multiple sclerosis following an initial episode of acute optic neuritis is significantly higher if there is a single brain MRI lesion; higher numbers of lesions do not appreciably increase that risk. However, even when brain lesions are seen on MRI, more than 40% of the patients will not develop clinical multiple sclerosis after 10 years. In the absence of MRI lesions, certain demographic and clinical features seem to predict a very low likelihood of developing multiple sclerosis. This natural history information is a critical input for estimating a patient's 10-year multiple sclerosis risk and for weighing the benefit of initiating prophylactic treatment at the time of optic neuritis or other initial demyelinating events in the central nervous system.
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Thompson, Laura M.; Staudinger, Michelle D.; Carter, Shawn L.
2015-09-29
A secretarial order identified climate adaptation as a critical performance objective for future management of U.S. Department of the Interior (DOI) lands and resources in response to global change. Vulnerability assessments can inform climate adaptation planning by providing insight into what natural resources are most at risk and why. Three components of vulnerability—exposure, sensitivity, and adaptive capacity—were defined by the Intergovernmental Panel on Climate Change (IPCC) as necessary for identifying climate adaptation strategies and actions. In 2011, the DOI requested all internal bureaus report ongoing or completed vulnerability assessments about a defined range of assessment targets or climate-related threats. Assessment targets were defined as freshwater resources, landscapes and wildlife habitat, native and cultural resources, and ocean health. Climate-related threats were defined as invasive species, wildfire risk, sea-level rise, and melting ice and permafrost. Four hundred and three projects were reported, but the original DOI survey did not specify that information be provided on exposure, sensitivity, and adaptive capacity collectively as part of the request, and it was unclear which projects adhered to the framework recommended by the IPCC. Therefore, the U.S. Geological Survey National Climate Change and Wildlife Science Center conducted a supplemental survey to determine how frequently each of the three vulnerability components was assessed. Information was categorized for 124 of the 403 reported projects (30.8 percent) based on the three vulnerability components, and it was discovered that exposure was the most common component assessed (87.9 percent), followed by sensitivity (68.5 percent) and adaptive capacity (33.1 percent). The majority of projects did not fully assess vulnerability; projects focused on landscapes/wildlife habitats and sea-level rise were among the minority that simultaneously addressed all three vulnerability components. To maintain consistency with the IPCC definition of vulnerability, DOI may want to focus initial climate adaptation planning only on the outcomes of studies that comprehensively address vulnerability as inclusive of exposure, sensitivity, and adaptive capacity. Although the present study results are preliminary and used an unstructured survey design, they illustrate the importance of a comprehensive and consistent vulnerability definition and of using information on vulnerability components in DOI surveys to ensure relevant data are used to identify adaptation options.
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43 CFR 17.339 - Exhaustion of administrative remedies.
Code of Federal Regulations, 2010 CFR
2010-10-01
... DOI has made no finding with regard to the complaint; or (2) DOI issues any finding in favor of the recipient. (b) If DOI fails to make a finding within 180 days or issues a finding in favor of the recipient, DOI will: (1) Promptly advise the complainant of this fact; (2) Advise the complainant of his or her...
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Code of Federal Regulations, 2010 CFR
2010-07-01
... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false What information must the Department of the Interior (DOI) furnish eligible public agencies? 102-75.635 Section 102-75.635... the Interior (DOI) furnish eligible public agencies? Upon request, DOI must furnish eligible public...
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Federal Register 2010, 2011, 2012, 2013, 2014
2010-09-10
... Investigations (DOI) as non- decisional staff in deliberations by the Commission in this docket. By this order... of Enforcement, Larry Parkinson, Director, DOI, and Geof Hobday of DOI to the January 15, 2009 list of staff excepted from the DOI non-decisional staff designation. Kimberly D. Bose, Secretary. [FR Doc...
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Code of Federal Regulations, 2011 CFR
2011-01-01
... 41 Public Contracts and Property Management 3 2011-01-01 2011-01-01 false What information must the Department of the Interior (DOI) furnish eligible public agencies? 102-75.635 Section 102-75.635... the Interior (DOI) furnish eligible public agencies? Upon request, DOI must furnish eligible public...
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30 CFR 250.1006 - How must I decommission and take out of service a DOI pipeline?
Code of Federal Regulations, 2011 CFR
2011-07-01
... a DOI pipeline? 250.1006 Section 250.1006 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT... out of service a DOI pipeline? (a) The requirements for decommissioning pipelines are listed in § 250.1750 through § 250.1754. (b) The table in this section lists the requirements if you take a DOI...
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Code of Federal Regulations, 2011 CFR
2011-01-01
... disposal agency receives the assignment recommendation from DOI? 102-75.665 Section 102-75.665 Public... assignment recommendation from DOI? If, after considering other uses for the property, the disposal agency approves the assignment recommendation from DOI, it must assign the property by letter or other document to...
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Depth of interaction decoding of a continuous crystal detector module.
Ling, T; Lewellen, T K; Miyaoka, R S
2007-04-21
We present a clustering method to extract the depth of interaction (DOI) information from an 8 mm thick crystal version of our continuous miniature crystal element (cMiCE) small animal PET detector. This clustering method, based on the maximum-likelihood (ML) method, can effectively build look-up tables (LUT) for different DOI regions. Combined with our statistics-based positioning (SBP) method, which uses a LUT searching algorithm based on the ML method and two-dimensional mean-variance LUTs of light responses from each photomultiplier channel with respect to different gamma ray interaction positions, the position of interaction and DOI can be estimated simultaneously. Data simulated using DETECT2000 were used to help validate our approach. An experiment using our cMiCE detector was designed to evaluate the performance. Two and four DOI region clustering were applied to the simulated data. Two DOI regions were used for the experimental data. The misclassification rate for simulated data is about 3.5% for two DOI regions and 10.2% for four DOI regions. For the experimental data, the rate is estimated to be approximately 25%. By using multi-DOI LUTs, we also observed improvement of the detector spatial resolution, especially for the corner region of the crystal. These results show that our ML clustering method is a consistent and reliable way to characterize DOI in a continuous crystal detector without requiring any modifications to the crystal or detector front end electronics. The ability to characterize the depth-dependent light response function from measured data is a major step forward in developing practical detectors with DOI positioning capability.
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Crystal structure and electronic properties of a thiolate-protected Au24 nanocluster
NASA Astrophysics Data System (ADS)
Das, Anindita; Li, Tao; Li, Gao; Nobusada, Katsuyuki; Zeng, Chenjie; Rosi, Nathaniel L.; Jin, Rongchao
2014-05-01
Solving the total structures of gold nanoclusters is of critical importance for understanding their electronic, optical and catalytic properties. Herein, we report the X-ray structure of a charge-neutral Au24(SCH2Ph-tBu)20 nanocluster. This structure features a bi-tetrahedral Au8 kernel protected by four tetrameric staple-like motifs. Electronic structure analysis is further carried out and the optical absorption spectrum is interpreted. The Au24(SCH2Ph-tBu)20, Au23(S-c-C6H11)16 and Au25(SCH2CH2Ph)18 nanoclusters constitute the first crystallographically characterized ``trio''.Solving the total structures of gold nanoclusters is of critical importance for understanding their electronic, optical and catalytic properties. Herein, we report the X-ray structure of a charge-neutral Au24(SCH2Ph-tBu)20 nanocluster. This structure features a bi-tetrahedral Au8 kernel protected by four tetrameric staple-like motifs. Electronic structure analysis is further carried out and the optical absorption spectrum is interpreted. The Au24(SCH2Ph-tBu)20, Au23(S-c-C6H11)16 and Au25(SCH2CH2Ph)18 nanoclusters constitute the first crystallographically characterized ``trio''. Electronic supplementary information (ESI) available: Experimental and supporting Fig. S1-S3. CCDC NUMBER(1000102). For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c4nr01350f
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NASA Astrophysics Data System (ADS)
Kang, Juhoon; Park, Chang-Goo; Lee, Su-Han; Cho, Changsoon; Choi, Dae-Geun; Lee, Jung-Yong
2016-05-01
In this report, we describe the fabrication of periodic Ag nanogrid electrodes by capillary assembly of silver nanoparticles (AgNPs) along patterned nanogrid templates. By assembling the AgNPs into these high-aspect-ratio nanogrid patterns, we can obtain high-aspect-ratio nanogratings, which can overcome the inherent trade-off between the optical transmittance and the sheet resistance of transparent electrodes. The junction resistance between the AgNPs is effectively reduced by photochemical welding and post-annealing. The fabricated high-aspect-ratio nanogrid structure with a line width of 150 nm and a height of 450 nm has a sheet resistance of 15.2 Ω sq-1 and an optical transmittance of 85.4%.In this report, we describe the fabrication of periodic Ag nanogrid electrodes by capillary assembly of silver nanoparticles (AgNPs) along patterned nanogrid templates. By assembling the AgNPs into these high-aspect-ratio nanogrid patterns, we can obtain high-aspect-ratio nanogratings, which can overcome the inherent trade-off between the optical transmittance and the sheet resistance of transparent electrodes. The junction resistance between the AgNPs is effectively reduced by photochemical welding and post-annealing. The fabricated high-aspect-ratio nanogrid structure with a line width of 150 nm and a height of 450 nm has a sheet resistance of 15.2 Ω sq-1 and an optical transmittance of 85.4%. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr01896c
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Thai National Telescope beam simulator testbed development status
NASA Astrophysics Data System (ADS)
Buisset, Christophe; Prasit, Apirat; Lépine, Thierry; Poshyachinda, Saran; Leckngam, A.
2016-07-01
The Thai National Telescope (TNT) is a Ritchey-Chretien Telescope with a clear aperture ΦM1 = 2.3 m, a focal ratio f/10 and a central obstruction Obsc = 0.3. The TNT is the main instrument of the Thai National Observatory (TNO) which is located near the summit of the Doi Inthanon, situated in the Chiang Mai Province of Thailand at altitude 2,457 meters. The median seeing on this site is approximately 0.9" and is remarkably stable on most nights, rarely exceeding 2". We decided to develop an optical setup to simulate in laboratory conditions the geometry of the TNT output beam. This, in order to carefully prepare and to improve the efficiency of the test to be performed in real conditions at the TNT focal plane level. We specified the setup to be representative of the TNT optical design, beam aperture, central obscuration, geometry of the spider, wavefront quality and PSF size under various seeing conditions. This setup comprises 2 identical Cassegrain telescopes mounted on dedicated supports with 5 degree-of-Freedom. The first application of this setup will be the preparation of the TNT optical alignment. The second application of this setup will be the development and the test of the future instruments for the TNT such as a focal reducer or a spectrograph. In this paper, we discuss the setup specifications we describe the setup optical and mechanical design and we present the performance.
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Evolution of NASA's Earth Science Digital Object Identifier Registration System
NASA Technical Reports Server (NTRS)
Wanchoo, Lalit; James, Nathan
2017-01-01
NASA's Earth Science Data and Information System (ESDIS) Project has implemented a fully automated system for assigning Digital Object Identifiers (DOIs) to Earth Science data products being managed by its network of 12 distributed active archive centers (DAACs). A key factor in the successful evolution of the DOI registration system over last 7 years has been the incorporation of community input from three focus groups under the NASA's Earth Science Data System Working Group (ESDSWG). These groups were largely composed of DOI submitters and data curators from the 12 data centers serving the user communities of various science disciplines. The suggestions from these groups were formulated into recommendations for ESDIS consideration and implementation. The ESDIS DOI registration system has evolved to be fully functional with over 5,000 publicly accessible DOIs and over 200 DOIs being held in reserve status until the information required for registration is obtained. The goal is to assign DOIs to the entire 8000+ data collections under ESDIS management via its network of discipline-oriented data centers. DOIs make it easier for researchers to discover and use earth science data and they enable users to provide valid citations for the data they use in research. Also for the researcher wishing to reproduce the results presented in science publications, the DOI can be used to locate the exact data or data products being cited.
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43 CFR 17.301 - What is the purpose of DOI's age discrimination regulations?
Code of Federal Regulations, 2010 CFR
2010-10-01
... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false What is the purpose of DOI's age... Age General § 17.301 What is the purpose of DOI's age discrimination regulations? The purpose of these regulations is to set out DOI's policies and procedures under the Age Discrimination Act of 1975 and the...
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Code of Federal Regulations, 2010 CFR
2010-07-01
... does DOI have after receiving the disposal agency's assignment letter? 102-75.670 Section 102-75.670... Property for Use As Public Park Or Recreation Areas § 102-75.670 What responsibilities does DOI have after..., the Secretary may proceed with the transfer. DOI must take all necessary actions to accomplish the...
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30 CFR 250.1006 - How must I decommission and take out of service a DOI pipeline?
Code of Federal Regulations, 2010 CFR
2010-07-01
... a DOI pipeline? 250.1006 Section 250.1006 Mineral Resources MINERALS MANAGEMENT SERVICE, DEPARTMENT... and Pipeline Rights-of-Way § 250.1006 How must I decommission and take out of service a DOI pipeline...) The table in this section lists the requirements if you take a DOI pipeline out of service: If you...
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43 CFR 2.31 - How will DOI respond to my appeal?
Code of Federal Regulations, 2010 CFR
2010-10-01
... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false How will DOI respond to my appeal? 2.31... OF INFORMATION ACT FOIA Appeals § 2.31 How will DOI respond to my appeal? (a) Appeals will be decided... will state the basis for DOI's decision as follows: (1) Decision to release or withhold records. (i) If...
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41 CFR 102-75.650 - When must DOI request assignment of the property?
Code of Federal Regulations, 2010 CFR
2010-07-01
... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false When must DOI request...-75.650 When must DOI request assignment of the property? Within 30 calendar days after the expiration of the 30-calendar day period specified in § 102-75.640, DOI must submit to the disposal agency an...
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Code of Federal Regulations, 2011 CFR
2011-01-01
... does DOI have after receiving the disposal agency's assignment letter? 102-75.670 Section 102-75.670... Property for Use As Public Park Or Recreation Areas § 102-75.670 What responsibilities does DOI have after..., the Secretary may proceed with the transfer. DOI must take all necessary actions to accomplish the...
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43 CFR 17.301 - What is the purpose of DOI's age discrimination regulations?
Code of Federal Regulations, 2011 CFR
2011-10-01
... 43 Public Lands: Interior 1 2011-10-01 2011-10-01 false What is the purpose of DOI's age... Age General § 17.301 What is the purpose of DOI's age discrimination regulations? The purpose of these regulations is to set out DOI's policies and procedures under the Age Discrimination Act of 1975 and the...
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41 CFR 102-75.650 - When must DOI request assignment of the property?
Code of Federal Regulations, 2011 CFR
2011-01-01
... 41 Public Contracts and Property Management 3 2011-01-01 2011-01-01 false When must DOI request...-75.650 When must DOI request assignment of the property? Within 30 calendar days after the expiration of the 30-calendar day period specified in § 102-75.640, DOI must submit to the disposal agency an...
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43 CFR 2.31 - How will DOI respond to my appeal?
Code of Federal Regulations, 2011 CFR
2011-10-01
... 43 Public Lands: Interior 1 2011-10-01 2011-10-01 false How will DOI respond to my appeal? 2.31... OF INFORMATION ACT FOIA Appeals § 2.31 How will DOI respond to my appeal? (a) Appeals will be decided... will state the basis for DOI's decision as follows: (1) Decision to release or withhold records. (i) If...
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[Congenital mydriasis as an initial sign of septo-optic dysplasia].
Carrascosa-Romero, M C; Ruiz-Cano, R; Martínez-López, F; Alfaro-Ponce, B; Pérez-Pardo, A
2013-10-01
Septo-optic dysplasia (SOD)[MIM182230] consisting of a heterogeneous and uncommon condition characterised by the classictriad: optic nerve hypoplasia, abnormalities of pituitary hormone, and defects of thebrain midline (including agenesis of the septum pellucidum and/or the corpus callosum; ithas also been described associated cortical malformations, it was referred to as SOD plus syndrome).We report the first known case in which the initial diagnostic sign of SOD was a bilateralmydriasis as a manifestation ofhypoplasia of both optic nerves, pituitary hypoplasia andcerebral dysgenesis with neuronal migration disorder.We discuss thedifferential diagnosis of congenital mydriasis. Copyright © 2010 Sociedad Española de Oftalmología. Published by Elsevier Espana. All rights reserved.
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The Last Millennium Reanalysis: Improvements to proxies and proxy modeling
NASA Astrophysics Data System (ADS)
Tardif, R.; Hakim, G. J.; Emile-Geay, J.; Noone, D.; Anderson, D. M.
2017-12-01
The Last Millennium Reanalysis (LMR) employs a paleoclimate data assimilation (PDA) approach to produce climate field reconstructions (CFRs). Here, we focus on two key factors in PDA generated CFRs: the set of assimilated proxy records and forward models (FMs) used to estimate proxies from climate model output. In the initial configuration of the LMR [Hakim et al., 2016], the proxy dataset of [PAGES2k Consortium, 2013] was used, along with univariate linear FMs calibrated against annually-averaged 20th century temperature datasets. In an updated configuration, proxy records from the recent dataset [PAGES2k Consortium, 2017] are used, while a hierarchy of statistical FMs are tested: (1) univariate calibrated on annual temperature as in the initial configuration, (2) univariate against temperature as in (1) but calibration performed using expert-derived seasonality for individual proxy records, (3) as in (2) but expert proxy seasonality replaced by seasonal averaging determined objectively as part of the calibration process, (4) linear objective seasonal FMs as in (3) but objectively selecting relationships calibrated either on temperature or precipitation, and (5) bivariate linear models calibrated on temperature and precipitation with objectively-derived seasonality. (4) and (5) specifically aim at better representing the physical drivers of tree ring width proxies. Reconstructions generated using the CCSM4 Last Millennium simulation as an uninformed prior are evaluated against various 20th century data products. Results show the benefits of using the new proxy collection, particularly on the detrended global mean temperature and spatial patterns. The positive impact of using proper seasonality and temperature/moisture sensitivities for tree ring width records is also notable. This updated configuration will be used for the first generation of LMR-generated CFRs to be publicly released. These also provide a benchmark for future efforts aimed at evaluating the impact of additional proxy records and/or more sophisticated physically-based forward models. References: Hakim, G. J., and co-authors (2016), J. Geophys. Res. Atmos., doi:10.1002/2016JD024751 PAGES2K Consortium (2013), Nat. Geosci., doi:10.1038/ngeo1797 PAGES2k Consortium (2017), Sci. Data. doi:10.1038/sdata.2017.88
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MO-F-CAMPUS-J-03: Development of a Human Brain PET for On-Line Proton Beam-Range Verification
DOE Office of Scientific and Technical Information (OSTI.GOV)
Shao, Yiping
Purpose: To develop a prototype PET for verifying proton beam-range before each fractionated therapy that will enable on-line re-planning proton therapy. Methods: Latest “edge-less” silicon photomultiplier arrays and customized ASIC readout electronics were used to develop PET detectors with depth-of-interaction (DOI) measurement capability. Each detector consists of one LYSO array with each end coupled to a SiPM array. Multiple detectors can be seamlessly tiled together to form a large detector panel. Detectors with 1.5×1.5 and 2.0×2.0 mm crystals at 20 or 30 mm lengths were studied. Readout of individual SiPM or signal multiplexing was used to transfer 3D interaction position-codedmore » analog signals through flexible-print-circuit cables or PCB board to dedicated ASIC front-end electronics to output digital timing pulses that encode interaction information. These digital pulses can be transferred to, through standard LVDS cables, and decoded by a FPGA-based data acquisition of coincidence events and data transfer. The modular detector and scalable electronics/data acquisition will enable flexible PET system configuration for different imaging geometry. Results: Initial detector performance measurement shows excellent crystal identification even with 30 mm long crystals, ∼18% and 2.8 ns energy and timing resolutions, and around 2–3 mm DOI resolution. A small prototype PET scanner with one detector ring has been built and evaluated, validating the technology and design. A large size detector panel has been fabricated by scaling up from modular detectors. Different designs of resistor and capacitor based signal multiplexing boards were tested and selected based on optimal crystal identification and timing performance. Stackable readout electronics boards and FPGA-based data acquisition boards were developed and tested. A brain PET is under construction. Conclusion: Technology of large-size DOI detector based on SiPM array and advanced readout has been developed. PET imaging performance and initial phantom studies of on-line proton beam-range measurement will be conducted and reported. NIH grant R21CA187717; Cancer Prevention and Research Institute of Texas grant RP120326.« less
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Combined advanced finishing and UV laser conditioning process for producing damage resistant optics
Menapace, Joseph A.; Peterson, John E.; Penetrante, Bernardino M.; Miller, Philip E.; Parham, Thomas G.; Nichols, Michael A.
2005-07-26
A method for reducing the density of sites on the surface of fused silica optics that are prone to the initiation of laser-induced damage, resulting in optics which have far fewer catastrophic defects, and are better capable of resisting optical deterioration upon exposure to a high-power laser beam.
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Spin-Orbit-Enhanced Functionality in LaAlO3/SrTiO3 Nanostructures
2015-09-16
34 J. Vis. Exp. 89 , e51886 (2014). http://dx.doi.org/doi:10.3791/51886 J. A. Sulpizio, S. Ilani, P. Irvin, and J. Levy, "Nanoscale Phenomena in Oxide... 89 , e51886 (2014). http://dx.doi.org/doi:10.3791/51886 J. A. Sulpizio, S. Ilani, P. Irvin, and J. Levy, "Nanoscale Phenomena in Oxide
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Code of Federal Regulations, 2010 CFR
2010-07-01
... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false When must DOI notify the... Disposal Property for Use As Public Park Or Recreation Areas § 102-75.640 When must DOI notify the disposal agency that an eligible applicant is interested in acquiring the property? DOI must notify the disposal...
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Peter Landres; Chris Barns; John G. Dennis; Tim Devine; Paul Geissler; Curtis S. McCasland; Linda Merigliano; Justin Seastrand; Ralph Swain
2008-01-01
The Interagency Wilderness Character Monitoring Team--representing the Department of the Interior (DOI) Bureau of Land Management, DOI Fish and Wildlife Service, DOI National Park Service, DOI U.S. Geological Survey, and the U.S. Forest Service-offers in this document an interagency strategy to monitor trends in wilderness character across the National Wilderness...
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Code of Federal Regulations, 2011 CFR
2011-01-01
... 41 Public Contracts and Property Management 3 2011-01-01 2011-01-01 false What happens if DOI does... Disposal Property for Use As Public Park Or Recreation Areas § 102-75.660 What happens if DOI does not approve any applications or does not submit an assignment recommendation? If DOI does not approve any...
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Code of Federal Regulations, 2011 CFR
2011-01-01
... 41 Public Contracts and Property Management 3 2011-01-01 2011-01-01 false When must DOI notify the... Disposal Property for Use As Public Park Or Recreation Areas § 102-75.640 When must DOI notify the disposal agency that an eligible applicant is interested in acquiring the property? DOI must notify the disposal...
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Bircher, Chad; Shao, Yiping
2012-01-01
Purpose: Positron emission tomography (PET) detectors that use a dual-ended-scintillator readout to measure depth-of-interaction (DOI) must have an accurate DOI function to provide the relationship between DOI and signal ratios to be used for detector calibration and recalibration. In a previous study, the authors used a novel and simple method to accurately and quickly measure DOI function by irradiating the detector with an external uniform flood source; however, as a practical concern, implementing external uniform flood sources in an assembled PET system is technically challenging and expensive. In the current study, therefore, the authors investigated whether the same method could be used to acquire DOI function from scintillator-generated (i.e., internal) radiation. The authors also developed a method for calibrating the energy scale necessary to select the events within the desired energy window. Methods: The authors measured the DOI function of a PET detector with lutetium yttrium orthosilicate (LYSO) scintillators. Radiation events originating from the scintillators’ internal Lu-176 beta decay were used to measure DOI functions which were then compared with those measured from both an external uniform flood source and an electronically collimated external point source. The authors conducted these studies with several scintillators of differing geometries (1.5 × 1.5 and 2.0 × 2.0 mm2 cross-section area and 20, 30, and 40 mm length) and various surface finishes (mirror-finishing, saw-cut rough, and other finishes in between), and in a prototype array. Results: All measured results using internal and external radiation sources showed excellent agreement in DOI function measurement. The mean difference among DOI values for all scintillators measured from internal and external radiation sources was less than 1.0 mm for different scintillator geometries and various surface finishes. Conclusions: The internal radioactivity of LYSO scintillators can be used to accurately measure DOI function in PET detectors, regardless of scintillator geometry or surface finish. Because an external radiation source is not needed, this method of DOI function measurement can be practically applied to individual PET detectors as well as assembled systems. PMID:22320787
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Bircher, Chad; Shao, Yiping
2012-02-01
Positron emission tomography (PET) detectors that use a dual-ended-scintillator readout to measure depth-of-interaction (DOI) must have an accurate DOI function to provide the relationship between DOI and signal ratios to be used for detector calibration and recalibration. In a previous study, the authors used a novel and simple method to accurately and quickly measure DOI function by irradiating the detector with an external uniform flood source; however, as a practical concern, implementing external uniform flood sources in an assembled PET system is technically challenging and expensive. In the current study, therefore, the authors investigated whether the same method could be used to acquire DOI function from scintillator-generated (i.e., internal) radiation. The authors also developed a method for calibrating the energy scale necessary to select the events within the desired energy window. The authors measured the DOI function of a PET detector with lutetium yttrium orthosilicate (LYSO) scintillators. Radiation events originating from the scintillators' internal Lu-176 beta decay were used to measure DOI functions which were then compared with those measured from both an external uniform flood source and an electronically collimated external point source. The authors conducted these studies with several scintillators of differing geometries (1.5 × 1.5 and 2.0 × 2.0 mm(2) cross-section area and 20, 30, and 40 mm length) and various surface finishes (mirror-finishing, saw-cut rough, and other finishes in between), and in a prototype array. All measured results using internal and external radiation sources showed excellent agreement in DOI function measurement. The mean difference among DOI values for all scintillators measured from internal and external radiation sources was less than 1.0 mm for different scintillator geometries and various surface finishes. The internal radioactivity of LYSO scintillators can be used to accurately measure DOI function in PET detectors, regardless of scintillator geometry or surface finish. Because an external radiation source is not needed, this method of DOI function measurement can be practically applied to individual PET detectors as well as assembled systems.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Bircher, Chad; Shao Yiping
Purpose: Positron emission tomography (PET) detectors that use a dual-ended-scintillator readout to measure depth-of-interaction (DOI) must have an accurate DOI function to provide the relationship between DOI and signal ratios to be used for detector calibration and recalibration. In a previous study, the authors used a novel and simple method to accurately and quickly measure DOI function by irradiating the detector with an external uniform flood source; however, as a practical concern, implementing external uniform flood sources in an assembled PET system is technically challenging and expensive. In the current study, therefore, the authors investigated whether the same method couldmore » be used to acquire DOI function from scintillator-generated (i.e., internal) radiation. The authors also developed a method for calibrating the energy scale necessary to select the events within the desired energy window. Methods: The authors measured the DOI function of a PET detector with lutetium yttrium orthosilicate (LYSO) scintillators. Radiation events originating from the scintillators' internal Lu-176 beta decay were used to measure DOI functions which were then compared with those measured from both an external uniform flood source and an electronically collimated external point source. The authors conducted these studies with several scintillators of differing geometries (1.5 x 1.5 and 2.0 x 2.0 mm{sup 2} cross-section area and 20, 30, and 40 mm length) and various surface finishes (mirror-finishing, saw-cut rough, and other finishes in between), and in a prototype array. Results: All measured results using internal and external radiation sources showed excellent agreement in DOI function measurement. The mean difference among DOI values for all scintillators measured from internal and external radiation sources was less than 1.0 mm for different scintillator geometries and various surface finishes. Conclusions: The internal radioactivity of LYSO scintillators can be used to accurately measure DOI function in PET detectors, regardless of scintillator geometry or surface finish. Because an external radiation source is not needed, this method of DOI function measurement can be practically applied to individual PET detectors as well as assembled systems.« less
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Phenotypic landscape inference reveals multiple evolutionary paths to C4 photosynthesis
Williams, Ben P; Johnston, Iain G; Covshoff, Sarah; Hibberd, Julian M
2013-01-01
C4 photosynthesis has independently evolved from the ancestral C3 pathway in at least 60 plant lineages, but, as with other complex traits, how it evolved is unclear. Here we show that the polyphyletic appearance of C4 photosynthesis is associated with diverse and flexible evolutionary paths that group into four major trajectories. We conducted a meta-analysis of 18 lineages containing species that use C3, C4, or intermediate C3–C4 forms of photosynthesis to parameterise a 16-dimensional phenotypic landscape. We then developed and experimentally verified a novel Bayesian approach based on a hidden Markov model that predicts how the C4 phenotype evolved. The alternative evolutionary histories underlying the appearance of C4 photosynthesis were determined by ancestral lineage and initial phenotypic alterations unrelated to photosynthesis. We conclude that the order of C4 trait acquisition is flexible and driven by non-photosynthetic drivers. This flexibility will have facilitated the convergent evolution of this complex trait. DOI: http://dx.doi.org/10.7554/eLife.00961.001 PMID:24082995
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Britz, Olivier; Zhang, Jingming; Grossmann, Katja S; Dyck, Jason; Kim, Jun C; Dymecki, Susan; Gosgnach, Simon; Goulding, Martyn
2015-01-01
V1 and V2b interneurons (INs) are essential for the production of an alternating flexor–extensor motor output. Using a tripartite genetic system to selectively ablate either V1 or V2b INs in the caudal spinal cord and assess their specific functions in awake behaving animals, we find that V1 and V2b INs function in an opposing manner to control flexor–extensor-driven movements. Ablation of V1 INs results in limb hyperflexion, suggesting that V1 IN-derived inhibition is needed for proper extension movements of the limb. The loss of V2b INs results in hindlimb hyperextension and a delay in the transition from stance phase to swing phase, demonstrating V2b INs are required for the timely initiation and execution of limb flexion movements. Our findings also reveal a bias in the innervation of flexor- and extensor-related motor neurons by V1 and V2b INs that likely contributes to their differential actions on flexion–extension movements. DOI: http://dx.doi.org/10.7554/eLife.04718.001 PMID:26465208
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Clouds not important for control of short-term surface temperatures
NASA Astrophysics Data System (ADS)
Schultz, Colin
2012-01-01
In two recent papers, R. W. Spencer and W. D. Braswell (Remote Sens., 3(8), 1603- 1613, doi:10.3390/rs3081603, 2011) (SB) and R. S. Lindzen and Y.-S. Choi (Asia Pac. J. Atmos. Sci., 47(4), 377-390, doi:10.1007/s13143-011-0023-x, 2011) (LC) argue that clouds act as a primary initiator of surface temperature changes in Earth's climate system. The two sets of authors reached this conclusion by developing a method that tries to determine the Earth's surface temperature by calculating how much energy is stored in the ocean's upper layers, how much of this heat is transferred to the rest of the climate system, how clouds affect the rate at which energy escapes Earth's atmosphere, and how the surface's energy flux changes with temperature. Both studies spurred substantial debate within the media and the public, with the research by SB causing the editor of the journal in which it was published to resign, claiming it should not have been accepted by the journal. Assessing the two studies, Dessler found what he suggests are a number of methodological errors.
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Comparative analysis of viral RNA signatures on different RIG-I-like receptors
Sanchez David, Raul Y; Combredet, Chantal; Sismeiro, Odile; Dillies, Marie-Agnès; Jagla, Bernd; Coppée, Jean-Yves; Mura, Marie; Guerbois Galla, Mathilde; Despres, Philippe; Tangy, Frédéric; Komarova, Anastassia V
2016-01-01
The RIG-I-like receptors (RLRs) play a major role in sensing RNA virus infection to initiate and modulate antiviral immunity. They interact with particular viral RNAs, most of them being still unknown. To decipher the viral RNA signature on RLRs during viral infection, we tagged RLRs (RIG-I, MDA5, LGP2) and applied tagged protein affinity purification followed by next-generation sequencing (NGS) of associated RNA molecules. Two viruses with negative- and positive-sense RNA genome were used: measles (MV) and chikungunya (CHIKV). NGS analysis revealed that distinct regions of MV genome were specifically recognized by distinct RLRs: RIG-I recognized defective interfering genomes, whereas MDA5 and LGP2 specifically bound MV nucleoprotein-coding region. During CHIKV infection, RIG-I associated specifically to the 3’ untranslated region of viral genome. This study provides the first comparative view of the viral RNA ligands for RIG-I, MDA5 and LGP2 in the presence of infection. DOI: http://dx.doi.org/10.7554/eLife.11275.001 PMID:27011352
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Dynamic metabolic exchange governs a marine algal-bacterial interaction
Segev, Einat; Wyche, Thomas P; Kim, Ki Hyun; Petersen, Jörn; Ellebrandt, Claire; Vlamakis, Hera; Barteneva, Natasha; Paulson, Joseph N; Chai, Liraz; Clardy, Jon; Kolter, Roberto
2016-01-01
Emiliania huxleyi is a model coccolithophore micro-alga that generates vast blooms in the ocean. Bacteria are not considered among the major factors influencing coccolithophore physiology. Here we show through a laboratory model system that the bacterium Phaeobacter inhibens, a well-studied member of the Roseobacter group, intimately interacts with E. huxleyi. While attached to the algal cell, bacteria initially promote algal growth but ultimately kill their algal host. Both algal growth enhancement and algal death are driven by the bacterially-produced phytohormone indole-3-acetic acid. Bacterial production of indole-3-acetic acid and attachment to algae are significantly increased by tryptophan, which is exuded from the algal cell. Algal death triggered by bacteria involves activation of pathways unique to oxidative stress response and programmed cell death. Our observations suggest that bacteria greatly influence the physiology and metabolism of E. huxleyi. Coccolithophore-bacteria interactions should be further studied in the environment to determine whether they impact micro-algal population dynamics on a global scale. DOI: http://dx.doi.org/10.7554/eLife.17473.001 PMID:27855786
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Roellig, Daniela; Tan-Cabugao, Johanna; Esaian, Sevan; Bronner, Marianne E
2017-01-01
The ‘neural plate border’ of vertebrate embryos contains precursors of neural crest and placode cells, both defining vertebrate characteristics. How these lineages segregate from neural and epidermal fates has been a matter of debate. We address this by performing a fine-scale quantitative temporal analysis of transcription factor expression in the neural plate border of chick embryos. The results reveal significant overlap of transcription factors characteristic of multiple lineages in individual border cells from gastrula through neurula stages. Cell fate analysis using a Sox2 (neural) enhancer reveals that cells that are initially Sox2+ cells can contribute not only to neural tube but also to neural crest and epidermis. Moreover, modulating levels of Sox2 or Pax7 alters the apportionment of neural tube versus neural crest fates. Our results resolve a long-standing question and suggest that many individual border cells maintain ability to contribute to multiple ectodermal lineages until or beyond neural tube closure. DOI: http://dx.doi.org/10.7554/eLife.21620.001 PMID:28355135
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Williams, Shawniqua T; Conte, Mary M; Goldfine, Andrew M; Noirhomme, Quentin; Gosseries, Olivia; Thonnard, Marie; Beattie, Bradley; Hersh, Jennifer; Katz, Douglas I; Victor, Jonathan D; Laureys, Steven; Schiff, Nicholas D
2013-01-01
Zolpidem produces paradoxical recovery of speech, cognitive and motor functions in select subjects with severe brain injury but underlying mechanisms remain unknown. In three diverse patients with known zolpidem responses we identify a distinctive pattern of EEG dynamics that suggests a mechanistic model. In the absence of zolpidem, all subjects show a strong low frequency oscillatory peak ∼6–10 Hz in the EEG power spectrum most prominent over frontocentral regions and with high coherence (∼0.7–0.8) within and between hemispheres. Zolpidem administration sharply reduces EEG power and coherence at these low frequencies. The ∼6–10 Hz activity is proposed to arise from intrinsic membrane properties of pyramidal neurons that are passively entrained across the cortex by locally-generated spontaneous activity. Activation by zolpidem is proposed to arise from a combination of initial direct drug effects on cortical, striatal, and thalamic populations and further activation of underactive brain regions induced by restoration of cognitively-mediated behaviors. DOI: http://dx.doi.org/10.7554/eLife.01157.001 PMID:24252875
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Smith, Benjamin A; Padrick, Shae B; Doolittle, Lynda K; Daugherty-Clarke, Karen; Corrêa, Ivan R; Xu, Ming-Qun; Goode, Bruce L; Rosen, Michael K; Gelles, Jeff
2013-01-01
During cell locomotion and endocytosis, membrane-tethered WASP proteins stimulate actin filament nucleation by the Arp2/3 complex. This process generates highly branched arrays of filaments that grow toward the membrane to which they are tethered, a conflict that seemingly would restrict filament growth. Using three-color single-molecule imaging in vitro we revealed how the dynamic associations of Arp2/3 complex with mother filament and WASP are temporally coordinated with initiation of daughter filament growth. We found that WASP proteins dissociated from filament-bound Arp2/3 complex prior to new filament growth. Further, mutations that accelerated release of WASP from filament-bound Arp2/3 complex proportionally accelerated branch formation. These data suggest that while WASP promotes formation of pre-nucleation complexes, filament growth cannot occur until it is triggered by WASP release. This provides a mechanism by which membrane-bound WASP proteins can stimulate network growth without restraining it. DOI: http://dx.doi.org/10.7554/eLife.01008.001 PMID:24015360
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The self-organization of grid cells in 3D
Stella, Federico; Treves, Alessandro
2015-01-01
Do we expect periodic grid cells to emerge in bats, or perhaps dolphins, exploring a three-dimensional environment? How long will it take? Our self-organizing model, based on ring-rate adaptation, points at a complex answer. The mathematical analysis leads to asymptotic states resembling face centered cubic (FCC) and hexagonal close packed (HCP) crystal structures, which are calculated to be very close to each other in terms of cost function. The simulation of the full model, however, shows that the approach to such asymptotic states involves several sub-processes over distinct time scales. The smoothing of the initially irregular multiple fields of individual units and their arrangement into hexagonal grids over certain best planes are observed to occur relatively quickly, even in large 3D volumes. The correct mutual orientation of the planes, though, and the coordinated arrangement of different units, take a longer time, with the network showing no sign of convergence towards either a pure FCC or HCP ordering. DOI: http://dx.doi.org/10.7554/eLife.05913.001 PMID:25821989
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Xu, Zijian; Wang, Wenjie; Jiang, Kaiju; Yu, Zhou; Huang, Huanwei; Wang, Fengchao; Zhou, Bin; Chen, Ting
2015-01-01
Long-term adult stem cells sustain tissue regeneration throughout the lifetime of an organism. They were hypothesized to originate from embryonic progenitor cells that acquire long-term self-renewal ability and multipotency at the end of organogenesis. The process through which this is achieved often remains unclear. Here, we discovered that long-term hair follicle stem cells arise from embryonic progenitor cells occupying a niche location that is defined by attenuated Wnt/β-catenin signaling. Hair follicle initiation is marked by placode formation, which depends on the activation of Wnt/β-catenin signaling. Soon afterwards, a region with attenuated Wnt/β-catenin signaling emerges in the upper follicle. Embryonic progenitor cells residing in this region gain expression of adult stem cell markers and become definitive long-term hair follicle stem cells at the end of organogenesis. Attenuation of Wnt/β-catenin signaling is a prerequisite for hair follicle stem cell specification because it suppresses Sox9, which is required for stem cell formation. DOI: http://dx.doi.org/10.7554/eLife.10567.001 PMID:26653852
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Structure of the active form of human origin recognition complex and its ATPase motor module
Tocilj, Ante; On, Kin Fan; Yuan, Zuanning; Sun, Jingchuan; Elkayam, Elad; Li, Huilin; Stillman, Bruce; Joshua-Tor, Leemor
2017-01-01
Binding of the Origin Recognition Complex (ORC) to origins of replication marks the first step in the initiation of replication of the genome in all eukaryotic cells. Here, we report the structure of the active form of human ORC determined by X-ray crystallography and cryo-electron microscopy. The complex is composed of an ORC1/4/5 motor module lobe in an organization reminiscent of the DNA polymerase clamp loader complexes. A second lobe contains the ORC2/3 subunits. The complex is organized as a double-layered shallow corkscrew, with the AAA+ and AAA+-like domains forming one layer, and the winged-helix domains (WHDs) forming a top layer. CDC6 fits easily between ORC1 and ORC2, completing the ring and the DNA-binding channel, forming an additional ATP hydrolysis site. Analysis of the ATPase activity of the complex provides a basis for understanding ORC activity as well as molecular defects observed in Meier-Gorlin Syndrome mutations. DOI: http://dx.doi.org/10.7554/eLife.20818.001 PMID:28112645
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Wotton, Karl R; Jiménez-Guri, Eva; Crombach, Anton; Janssens, Hilde; Alcaine-Colet, Anna; Lemke, Steffen; Schmidt-Ott, Urs; Jaeger, Johannes
2015-01-01
The segmentation gene network in insects can produce equivalent phenotypic outputs despite differences in upstream regulatory inputs between species. We investigate the mechanistic basis of this phenomenon through a systems-level analysis of the gap gene network in the scuttle fly Megaselia abdita (Phoridae). It combines quantification of gene expression at high spatio-temporal resolution with systematic knock-downs by RNA interference (RNAi). Initiation and dynamics of gap gene expression differ markedly between M. abdita and Drosophila melanogaster, while the output of the system converges to equivalent patterns at the end of the blastoderm stage. Although the qualitative structure of the gap gene network is conserved, there are differences in the strength of regulatory interactions between species. We term such network rewiring ‘quantitative system drift’. It provides a mechanistic explanation for the developmental hourglass model in the dipteran lineage. Quantitative system drift is likely to be a widespread mechanism for developmental evolution. DOI: http://dx.doi.org/10.7554/eLife.04785.001 PMID:25560971
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Shah, Neel H; Wang, Qi; Yan, Qingrong; Karandur, Deepti; Kadlecek, Theresa A; Fallahee, Ian R; Russ, William P; Ranganathan, Rama; Weiss, Arthur; Kuriyan, John
2016-01-01
The sequence of events that initiates T cell signaling is dictated by the specificities and order of activation of the tyrosine kinases that signal downstream of the T cell receptor. Using a platform that combines exhaustive point-mutagenesis of peptide substrates, bacterial surface-display, cell sorting, and deep sequencing, we have defined the specificities of the first two kinases in this pathway, Lck and ZAP-70, for the T cell receptor ζ chain and the scaffold proteins LAT and SLP-76. We find that ZAP-70 selects its substrates by utilizing an electrostatic mechanism that excludes substrates with positively-charged residues and favors LAT and SLP-76 phosphosites that are surrounded by negatively-charged residues. This mechanism prevents ZAP-70 from phosphorylating its own activation loop, thereby enforcing its strict dependence on Lck for activation. The sequence features in ZAP-70, LAT, and SLP-76 that underlie electrostatic selectivity likely contribute to the specific response of T cells to foreign antigens. DOI: http://dx.doi.org/10.7554/eLife.20105.001 PMID:27700984
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Pourkarimi, Ehsan; Bellush, James M; Whitehouse, Iestyn
2016-01-01
The primary task of developing embryos is genome replication, yet how DNA replication is integrated with the profound cellular changes that occur through development is largely unknown. Using an approach to map DNA replication at high resolution in C. elegans, we show that replication origins are marked with specific histone modifications that define gene enhancers. We demonstrate that the level of enhancer associated modifications scale with the efficiency at which the origin is utilized. By mapping replication origins at different developmental stages, we show that the positions and activity of origins is largely invariant through embryogenesis. Contrary to expectation, we find that replication origins are specified prior to the broad onset of zygotic transcription, yet when transcription initiates it does so in close proximity to the pre-defined replication origins. Transcription and DNA replication origins are correlated, but the association breaks down when embryonic cell division ceases. Collectively, our data indicate that replication origins are fundamental organizers and regulators of gene activity through embryonic development. DOI: http://dx.doi.org/10.7554/eLife.21728.001 PMID:28009254
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Isobe, Taichi; Hisamori, Shigeo; Hogan, Daniel J; Zabala, Maider; Hendrickson, David G; Dalerba, Piero; Cai, Shang; Scheeren, Ferenc; Kuo, Angera H; Sikandar, Shaheen S; Lam, Jessica S; Qian, Dalong; Dirbas, Frederick M; Somlo, George; Lao, Kaiqin; Brown, Patrick O; Clarke, Michael F; Shimono, Yohei
2014-01-01
MicroRNAs (miRNAs) are important regulators of stem and progenitor cell functions. We previously reported that miR-142 and miR-150 are upregulated in human breast cancer stem cells (BCSCs) as compared to the non-tumorigenic breast cancer cells. In this study, we report that miR-142 efficiently recruits the APC mRNA to an RNA-induced silencing complex, activates the canonical WNT signaling pathway in an APC-suppression dependent manner, and activates the expression of miR-150. Enforced expression of miR-142 or miR-150 in normal mouse mammary stem cells resulted in the regeneration of hyperproliferative mammary glands in vivo. Knockdown of endogenous miR-142 effectively suppressed organoid formation by BCSCs and slowed tumor growth initiated by human BCSCs in vivo. These results suggest that in some tumors, miR-142 regulates the properties of BCSCs at least in part by activating the WNT signaling pathway and miR-150 expression. DOI: http://dx.doi.org/10.7554/eLife.01977.001 PMID:25406066
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A user-friendly, open-source tool to project impact and cost of diagnostic tests for tuberculosis
Dowdy, David W; Andrews, Jason R; Dodd, Peter J; Gilman, Robert H
2014-01-01
Most models of infectious diseases, including tuberculosis (TB), do not provide results customized to local conditions. We created a dynamic transmission model to project TB incidence, TB mortality, multidrug-resistant (MDR) TB prevalence, and incremental costs over 5 years after scale-up of nine alternative diagnostic strategies. A corresponding web-based interface allows users to specify local costs and epidemiology. In settings with little capacity for up-front investment, same-day microscopy had the greatest impact on TB incidence and became cost-saving within 5 years if delivered at $10/test. With greater initial investment, population-level scale-up of Xpert MTB/RIF or microcolony-based culture often averted 10 times more TB cases than narrowly-targeted strategies, at minimal incremental long-term cost. Xpert for smear-positive TB had reasonable impact on MDR-TB incidence, but at substantial price and little impact on overall TB incidence and mortality. This user-friendly modeling framework improves decision-makers' ability to evaluate the local impact of TB diagnostic strategies. DOI: http://dx.doi.org/10.7554/eLife.02565.001 PMID:24898755
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Apoptotic cells can induce non-autonomous apoptosis through the TNF pathway
Pérez-Garijo, Ainhoa; Fuchs, Yaron; Steller, Hermann
2013-01-01
Apoptotic cells can produce signals to instruct cells in their local environment, including ones that stimulate engulfment and proliferation. We identified a novel mode of communication by which apoptotic cells induce additional apoptosis in the same tissue. Strong induction of apoptosis in one compartment of the Drosophila wing disc causes apoptosis of cells in the other compartment, indicating that dying cells can release long-range death factors. We identified Eiger, the Drosophila tumor necrosis factor (TNF) homolog, as the signal responsible for apoptosis-induced apoptosis (AiA). Eiger is produced in apoptotic cells and, through activation of the c-Jun N-terminal kinase (JNK) pathway, is able to propagate the initial apoptotic stimulus. We also show that during coordinated cell death of hair follicle cells in mice, TNF-α is expressed in apoptotic cells and is required for normal cell death. AiA provides a mechanism to explain cohort behavior of dying cells that is seen both in normal development and under pathological conditions. DOI: http://dx.doi.org/10.7554/eLife.01004.001 PMID:24066226
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Heterochromatin assembly by interrupted Sir3 bridges across neighboring nucleosomes
Behrouzi, Reza; Lu, Chenning; Currie, Mark A; Jih, Gloria; Iglesias, Nahid; Moazed, Danesh
2016-01-01
Heterochromatin is a conserved feature of eukaryotic chromosomes with central roles in regulation of gene expression and maintenance of genome stability. Heterochromatin formation involves spreading of chromatin-modifying factors away from initiation points over large DNA domains by poorly understood mechanisms. In Saccharomyces cerevisiae, heterochromatin formation requires the SIR complex, which contains subunits with histone-modifying, histone-binding, and self-association activities. Here, we analyze binding of the Sir proteins to reconstituted mono-, di-, tri-, and tetra-nucleosomal chromatin templates and show that key Sir-Sir interactions bridge only sites on different nucleosomes but not sites on the same nucleosome, and are therefore 'interrupted' with respect to sites on the same nucleosome. We observe maximal binding affinity and cooperativity to unmodified di-nucleosomes and propose that nucleosome pairs bearing unmodified histone H4-lysine16 and H3-lysine79 form the fundamental units of Sir chromatin binding and that cooperative binding requiring two appropriately modified nucleosomes mediates selective Sir recruitment and spreading. DOI: http://dx.doi.org/10.7554/eLife.17556.001 PMID:27835568
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Serial grouping of 2D-image regions with object-based attention in humans
Jeurissen, Danique; Self, Matthew W; Roelfsema, Pieter R
2016-01-01
After an initial stage of local analysis within the retina and early visual pathways, the human visual system creates a structured representation of the visual scene by co-selecting image elements that are part of behaviorally relevant objects. The mechanisms underlying this perceptual organization process are only partially understood. We here investigate the time-course of perceptual grouping of two-dimensional image-regions by measuring the reaction times of human participants and report that it is associated with the gradual spread of object-based attention. Attention spreads fastest over large and homogeneous areas and is slowed down at locations that require small-scale processing. We find that the time-course of the object-based selection process is well explained by a 'growth-cone' model, which selects surface elements in an incremental, scale-dependent manner. We discuss how the visual cortical hierarchy can implement this scale-dependent spread of object-based attention, leveraging the different receptive field sizes in distinct cortical areas. DOI: http://dx.doi.org/10.7554/eLife.14320.001 PMID:27291188
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Dodonova, Svetlana O; Aderhold, Patrick; Kopp, Juergen; Ganeva, Iva; Röhling, Simone; Hagen, Wim J H; Sinning, Irmgard; Wieland, Felix; Briggs, John A G
2017-01-01
COPI coated vesicles mediate trafficking within the Golgi apparatus and between the Golgi and the endoplasmic reticulum. Assembly of a COPI coated vesicle is initiated by the small GTPase Arf1 that recruits the coatomer complex to the membrane, triggering polymerization and budding. The vesicle uncoats before fusion with a target membrane. Coat components are structurally conserved between COPI and clathrin/adaptor proteins. Using cryo-electron tomography and subtomogram averaging, we determined the structure of the COPI coat assembled on membranes in vitro at 9 Å resolution. We also obtained a 2.57 Å resolution crystal structure of βδ-COP. By combining these structures we built a molecular model of the coat. We additionally determined the coat structure in the presence of ArfGAP proteins that regulate coat dissociation. We found that Arf1 occupies contrasting molecular environments within the coat, leading us to hypothesize that some Arf1 molecules may regulate vesicle assembly while others regulate coat disassembly. DOI: http://dx.doi.org/10.7554/eLife.26691.001 PMID:28621666
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Redhu, Naresh S; Bakthavatchalu, Vasudevan; Conaway, Evan A; Shouval, Dror S; Tsou, Amy; Goettel, Jeremy A; Biswas, Amlan; Wang, Chuanwu; Field, Michael; Muller, Werner; Bleich, Andre; Li, Ning; Gerber, Georg K; Bry, Lynn; Fox, James G; Snapper, Scott B; Horwitz, Bruce H
2017-01-01
Infants with defects in the interleukin 10 receptor (IL10R) develop very early onset inflammatory bowel disease. Whether IL10R regulates lamina propria macrophage function during infant development in mice and whether macrophage-intrinsic IL10R signaling is required to prevent colitis in infancy is unknown. Here we show that although signs of colitis are absent in IL10R-deficient mice during the first two weeks of life, intestinal inflammation and macrophage dysfunction begin during the third week of life, concomitant with weaning and accompanying diversification of the intestinal microbiota. However, IL10R did not directly regulate the microbial ecology during infant development. Interestingly, macrophage depletion with clodronate inhibited the development of colitis, while the absence of IL10R specifically on macrophages sensitized infant mice to the development of colitis. These results indicate that IL10R-mediated regulation of macrophage function during the early postnatal period is indispensable for preventing the development of murine colitis. DOI: http://dx.doi.org/10.7554/eLife.27652.001 PMID:28678006
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Molecular architecture of the yeast Mediator complex
Robinson, Philip J; Trnka, Michael J; Pellarin, Riccardo; Greenberg, Charles H; Bushnell, David A; Davis, Ralph; Burlingame, Alma L; Sali, Andrej; Kornberg, Roger D
2015-01-01
The 21-subunit Mediator complex transduces regulatory information from enhancers to promoters, and performs an essential role in the initiation of transcription in all eukaryotes. Structural information on two-thirds of the complex has been limited to coarse subunit mapping onto 2-D images from electron micrographs. We have performed chemical cross-linking and mass spectrometry, and combined the results with information from X-ray crystallography, homology modeling, and cryo-electron microscopy by an integrative modeling approach to determine a 3-D model of the entire Mediator complex. The approach is validated by the use of X-ray crystal structures as internal controls and by consistency with previous results from electron microscopy and yeast two-hybrid screens. The model shows the locations and orientations of all Mediator subunits, as well as subunit interfaces and some secondary structural elements. Segments of 20–40 amino acid residues are placed with an average precision of 20 Å. The model reveals roles of individual subunits in the organization of the complex. DOI: http://dx.doi.org/10.7554/eLife.08719.001 PMID:26402457
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Ankers, John M; Awais, Raheela; Jones, Nicholas A; Boyd, James; Ryan, Sheila; Adamson, Antony D; Harper, Claire V; Bridge, Lloyd; Spiller, David G; Jackson, Dean A; Paszek, Pawel; Sée, Violaine; White, Michael RH
2016-01-01
Dynamic cellular systems reprogram gene expression to ensure appropriate cellular fate responses to specific extracellular cues. Here we demonstrate that the dynamics of Nuclear Factor kappa B (NF-κB) signalling and the cell cycle are prioritised differently depending on the timing of an inflammatory signal. Using iterative experimental and computational analyses, we show physical and functional interactions between NF-κB and the E2 Factor 1 (E2F-1) and E2 Factor 4 (E2F-4) cell cycle regulators. These interactions modulate the NF-κB response. In S-phase, the NF-κB response was delayed or repressed, while cell cycle progression was unimpeded. By contrast, activation of NF-κB at the G1/S boundary resulted in a longer cell cycle and more synchronous initial NF-κB responses between cells. These data identify new mechanisms by which the cellular response to stress is differentially controlled at different stages of the cell cycle. DOI: http://dx.doi.org/10.7554/eLife.10473.001 PMID:27185527
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Mechanism and preclinical prevention of increased breast cancer risk caused by pregnancy
Haricharan, Svasti; Dong, Jie; Hein, Sarah; Reddy, Jay P; Du, Zhijun; Toneff, Michael; Holloway, Kimberly; Hilsenbeck, Susan G; Huang, Shixia; Atkinson, Rachel; Woodward, Wendy; Jindal, Sonali; Borges, Virginia F; Gutierrez, Carolina; Zhang, Hong; Schedin, Pepper J; Osborne, C Kent; Tweardy, David J; Li, Yi
2013-01-01
While a first pregnancy before age 22 lowers breast cancer risk, a pregnancy after age 35 significantly increases life-long breast cancer risk. Pregnancy causes several changes to the normal breast that raise barriers to transformation, but how pregnancy can also increase cancer risk remains unclear. We show in mice that pregnancy has different effects on the few early lesions that have already developed in the otherwise normal breast—it causes apoptosis evasion and accelerated progression to cancer. The apoptosis evasion is due to the normally tightly controlled STAT5 signaling going astray—these precancerous cells activate STAT5 in response to pregnancy/lactation hormones and maintain STAT5 activation even during involution, thus preventing the apoptosis normally initiated by oncoprotein and involution. Short-term anti-STAT5 treatment of lactation-completed mice bearing early lesions eliminates the increased risk after a pregnancy. This chemoprevention strategy has important implications for preventing increased human breast cancer risk caused by pregnancy. DOI: http://dx.doi.org/10.7554/eLife.00996.001 PMID:24381245
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Microtubules provide directional information for core PCP function
Matis, Maja; Russler-Germain, David A; Hu, Qie; Tomlin, Claire J; Axelrod, Jeffrey D
2014-01-01
Planar cell polarity (PCP) signaling controls the polarization of cells within the plane of an epithelium. Two molecular modules composed of Fat(Ft)/Dachsous(Ds)/Four-jointed(Fj) and a ‘PCP-core’ including Frizzled(Fz) and Dishevelled(Dsh) contribute to polarization of individual cells. How polarity is globally coordinated with tissue axes is unresolved. Consistent with previous results, we find that the Ft/Ds/Fj-module has an effect on a MT-cytoskeleton. Here, we provide evidence for the model that the Ft/Ds/Fj-module provides directional information to the core-module through this MT organizing function. We show Ft/Ds/Fj-dependent initial polarization of the apical MT-cytoskeleton prior to global alignment of the core-module, reveal that the anchoring of apical non-centrosomal MTs at apical junctions is polarized, observe that directional trafficking of vesicles containing Dsh depends on Ft, and demonstrate the feasibility of this model by mathematical simulation. Together, these results support the hypothesis that Ft/Ds/Fj provides a signal to orient core PCP function via MT polarization. DOI: http://dx.doi.org/10.7554/eLife.02893.001 PMID:25124458
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Raj, Ganesh V; Sareddy, Gangadhara Reddy; Ma, Shihong; Lee, Tae-Kyung; Viswanadhapalli, Suryavathi; Li, Rui; Liu, Xihui; Murakami, Shino; Chen, Chien-Cheng; Lee, Wan-Ru; Mann, Monica; Krishnan, Samaya Rajeshwari; Manandhar, Bikash; Gonugunta, Vijay K; Strand, Douglas; Tekmal, Rajeshwar Rao; Ahn, Jung-Mo; Vadlamudi, Ratna K
2017-01-01
The majority of human breast cancer is estrogen receptor alpha (ER) positive. While anti-estrogens/aromatase inhibitors are initially effective, resistance to these drugs commonly develops. Therapy-resistant tumors often retain ER signaling, via interaction with critical oncogenic coregulator proteins. To address these mechanisms of resistance, we have developed a novel ER coregulator binding modulator, ERX-11. ERX-11 interacts directly with ER and blocks the interaction between a subset of coregulators with both native and mutant forms of ER. ERX-11 effectively blocks ER-mediated oncogenic signaling and has potent anti-proliferative activity against therapy-sensitive and therapy-resistant human breast cancer cells. ERX-11 is orally bioavailable, with no overt signs of toxicity and potent activity in both murine xenograft and patient-derived breast tumor explant models. This first-in-class agent, with its novel mechanism of action of disrupting critical protein-protein interactions, overcomes the limitations of current therapies and may be clinically translatable for patients with therapy-sensitive and therapy-resistant breast cancers. DOI: http://dx.doi.org/10.7554/eLife.26857.001 PMID:28786813
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Kim, Yujin; Hsu, Ching-Lung; Cembrowski, Mark S; Mensh, Brett D; Spruston, Nelson
2015-01-01
Dendritic integration of synaptic inputs mediates rapid neural computation as well as longer-lasting plasticity. Several channel types can mediate dendritically initiated spikes (dSpikes), which may impact information processing and storage across multiple timescales; however, the roles of different channels in the rapid vs long-term effects of dSpikes are unknown. We show here that dSpikes mediated by Nav channels (blocked by a low concentration of TTX) are required for long-term potentiation (LTP) in the distal apical dendrites of hippocampal pyramidal neurons. Furthermore, imaging, simulations, and buffering experiments all support a model whereby fast Nav channel-mediated dSpikes (Na-dSpikes) contribute to LTP induction by promoting large, transient, localized increases in intracellular calcium concentration near the calcium-conducting pores of NMDAR and L-type Cav channels. Thus, in addition to contributing to rapid neural processing, Na-dSpikes are likely to contribute to memory formation via their role in long-lasting synaptic plasticity. DOI: http://dx.doi.org/10.7554/eLife.06414.001 PMID:26247712
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Mechanism of synergistic activation of Arp2/3 complex by cortactin and N-WASP
Helgeson, Luke A; Nolen, Brad J
2013-01-01
Nucleation promoting factors (NPFs) initiate branched actin network assembly by activating Arp2/3 complex, a branched actin filament nucleator. Cellular actin networks contain multiple NPFs, but how they coordinately regulate Arp2/3 complex is unclear. Cortactin is an NPF that activates Arp2/3 complex weakly on its own, but with WASP/N-WASP, another class of NPFs, potently activates. We dissect the mechanism of synergy and propose a model in which cortactin displaces N-WASP from nascent branches as a prerequisite for nucleation. Single-molecule imaging revealed that unlike WASP/N-WASP, cortactin remains bound to junctions during nucleation, and specifically targets junctions with a ∼160-fold increased on rate over filament sides. N-WASP must be dimerized for potent synergy, and targeted mutations indicate release of dimeric N-WASP from nascent branches limits nucleation. Mathematical modeling shows cortactin-mediated displacement but not N-WASP recycling or filament recruitment models can explain synergy. Our results provide a molecular basis for coordinate Arp2/3 complex regulation. DOI: http://dx.doi.org/10.7554/eLife.00884.001 PMID:24015358
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Brown, Jennifer; Pan, Wei-Xing; Dudman, Joshua Tate
2014-05-21
Dysfunction of the basal ganglia produces severe deficits in the timing, initiation, and vigor of movement. These diverse impairments suggest a control system gone awry. In engineered systems, feedback is critical for control. By contrast, models of the basal ganglia highlight feedforward circuitry and ignore intrinsic feedback circuits. In this study, we show that feedback via axon collaterals of substantia nigra projection neurons control the gain of the basal ganglia output. Through a combination of physiology, optogenetics, anatomy, and circuit mapping, we elaborate a general circuit mechanism for gain control in a microcircuit lacking interneurons. Our data suggest that diverse tonic firing rates, weak unitary connections and a spatially diffuse collateral circuit with distinct topography and kinetics from feedforward input is sufficient to implement divisive feedback inhibition. The importance of feedback for engineered systems implies that the intranigral microcircuit, despite its absence from canonical models, could be essential to basal ganglia function. DOI: http://dx.doi.org/10.7554/eLife.02397.001. Copyright © 2014, Brown et al.
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Kümper, Sandra; Mardakheh, Faraz K; McCarthy, Afshan; Yeo, Maggie; Stamp, Gordon W; Paul, Angela; Worboys, Jonathan; Sadok, Amine; Jørgensen, Claus; Guichard, Sabrina
2016-01-01
Rho-associated kinases 1 and 2 (ROCK1/2) are Rho-GTPase effectors that control key aspects of the actin cytoskeleton, but their role in proliferation and cancer initiation or progression is not known. Here, we provide evidence that ROCK1 and ROCK2 act redundantly to maintain actomyosin contractility and cell proliferation and that their loss leads to cell-cycle arrest and cellular senescence. This phenotype arises from down-regulation of the essential cell-cycle proteins CyclinA, CKS1 and CDK1. Accordingly, while the loss of either Rock1 or Rock2 had no negative impact on tumorigenesis in mouse models of non-small cell lung cancer and melanoma, loss of both blocked tumor formation, as no tumors arise in which both Rock1 and Rock2 have been genetically deleted. Our results reveal an indispensable role for ROCK, yet redundant role for isoforms 1 and 2, in cell cycle progression and tumorigenesis, possibly through the maintenance of cellular contractility. DOI: http://dx.doi.org/10.7554/eLife.12203.001 PMID:26765561
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A conserved MCM single-stranded DNA binding element is essential for replication initiation.
Froelich, Clifford A; Kang, Sukhyun; Epling, Leslie B; Bell, Stephen P; Enemark, Eric J
2014-04-01
The ring-shaped MCM helicase is essential to all phases of DNA replication. The complex loads at replication origins as an inactive double-hexamer encircling duplex DNA. Helicase activation converts this species to two active single hexamers that encircle single-stranded DNA (ssDNA). The molecular details of MCM DNA interactions during these events are unknown. We determined the crystal structure of the Pyrococcus furiosus MCM N-terminal domain hexamer bound to ssDNA and define a conserved MCM-ssDNA binding motif (MSSB). Intriguingly, ssDNA binds the MCM ring interior perpendicular to the central channel with defined polarity. In eukaryotes, the MSSB is conserved in several Mcm2-7 subunits, and MSSB mutant combinations in S. cerevisiae Mcm2-7 are not viable. Mutant Mcm2-7 complexes assemble and are recruited to replication origins, but are defective in helicase loading and activation. Our findings identify an important MCM-ssDNA interaction and suggest it functions during helicase activation to select the strand for translocation. DOI: http://dx.doi.org/10.7554/eLife.01993.001.
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A conserved MCM single-stranded DNA binding element is essential for replication initiation
Froelich, Clifford A; Kang, Sukhyun; Epling, Leslie B; Bell, Stephen P; Enemark, Eric J
2014-01-01
The ring-shaped MCM helicase is essential to all phases of DNA replication. The complex loads at replication origins as an inactive double-hexamer encircling duplex DNA. Helicase activation converts this species to two active single hexamers that encircle single-stranded DNA (ssDNA). The molecular details of MCM DNA interactions during these events are unknown. We determined the crystal structure of the Pyrococcus furiosus MCM N-terminal domain hexamer bound to ssDNA and define a conserved MCM-ssDNA binding motif (MSSB). Intriguingly, ssDNA binds the MCM ring interior perpendicular to the central channel with defined polarity. In eukaryotes, the MSSB is conserved in several Mcm2-7 subunits, and MSSB mutant combinations in S. cerevisiae Mcm2-7 are not viable. Mutant Mcm2-7 complexes assemble and are recruited to replication origins, but are defective in helicase loading and activation. Our findings identify an important MCM-ssDNA interaction and suggest it functions during helicase activation to select the strand for translocation. DOI: http://dx.doi.org/10.7554/eLife.01993.001 PMID:24692448
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Basic Performance Test of a Prototype PET Scanner Using CdTe Semiconductor Detectors
NASA Astrophysics Data System (ADS)
Ueno, Y.; Morimoto, Y.; Tsuchiya, K.; Yanagita, N.; Kojima, S.; Ishitsu, T.; Kitaguchi, H.; Kubo, N.; Zhao, S.; Tamaki, N.; Amemiya, K.
2009-02-01
A prototype positron emission tomography (PET) scanner using CdTe semiconductor detectors was developed, and its initial evaluation was conducted. The scanner was configured to form a single detector ring with six separated detector units, each having 96 detectors arranged in three detector layers. The field of view (FOV) size was 82 mm in diameter. Basic physical performance indicators of the scanner were measured through phantom studies and confirmed by rat imaging. The system-averaged energy resolution and timing resolution were 5.4% and 6.0 ns (each in FWHM) respectively. Spatial resolution measured at FOV center was 2.6 mm FWHM. Scatter fraction was measured and calculated in a National Electrical Manufacturers Association (NEMA)-fashioned manner using a 3-mm diameter hot capillary in a water-filled 80-mm diameter acrylic cylinder. The calculated result was 3.6%. Effect of depth of interaction (DOI) measurement was demonstrated by comparing hot-rod phantom images reconstructed with and without DOI information. Finally, images of a rat myocardium and an implanted tumor were visually assessed, and the imaging performance was confirmed.
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Barry, Kevin C; Ingolia, Nicholas T; Vance, Russell E
2017-01-01
The inducible innate immune response to infection requires a concerted process of gene expression that is regulated at multiple levels. Most global analyses of the innate immune response have focused on transcription induced by defined immunostimulatory ligands, such as lipopolysaccharide. However, the response to pathogens involves additional complexity, as pathogens interfere with virtually every step of gene expression. How cells respond to pathogen-mediated disruption of gene expression to nevertheless initiate protective responses remains unclear. We previously discovered that a pathogen-mediated blockade of host protein synthesis provokes the production of specific pro-inflammatory cytokines. It remains unclear how these cytokines are produced despite the global pathogen-induced block of translation. We addressed this question by using parallel RNAseq and ribosome profiling to characterize the response of macrophages to infection with the intracellular bacterial pathogen Legionella pneumophila. Our results reveal that mRNA superinduction is required for the inducible immune response to a bacterial pathogen. DOI: http://dx.doi.org/10.7554/eLife.22707.001 PMID:28383283
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Cottee, Matthew A; Muschalik, Nadine; Johnson, Steven; Leveson, Joanna; Raff, Jordan W; Lea, Susan M
2015-01-01
Sas-6 and Ana2/STIL proteins are required for centriole duplication and the homo-oligomerisation properties of Sas-6 help establish the ninefold symmetry of the central cartwheel that initiates centriole assembly. Ana2/STIL proteins are poorly conserved, but they all contain a predicted Central Coiled-Coil Domain (CCCD). Here we show that the Drosophila Ana2 CCCD forms a tetramer, and we solve its structure to 0.8 Å, revealing that it adopts an unusual parallel-coil topology. We also solve the structure of the Drosophila Sas-6 N-terminal domain to 2.9 Å revealing that it forms higher-order oligomers through canonical interactions. Point mutations that perturb Sas-6 or Ana2 homo-oligomerisation in vitro strongly perturb centriole assembly in vivo. Thus, efficient centriole duplication in flies requires the homo-oligomerisation of both Sas-6 and Ana2, and the Ana2 CCCD tetramer structure provides important information on how these proteins might cooperate to form a cartwheel structure. DOI: http://dx.doi.org/10.7554/eLife.07236.001 PMID:26002084
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Feedback and Acousto Optic Isolation Effects on Laser Stability.
1977-03-01
This paper analyzes the effect of optical feedback on laser frequency stability and the acousto optic isolator concept, which was demonstrated...nonlinearity such as saturation in the laser medium. The analysis mathematically corroborates the initial acousto optic isolator concept and the...limited experimental data available. In the study of the acousto optic isolator, it was determined that an acceptable analytic expression for the
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Roncali, Emilie; Phipps, Jennifer E; Marcu, Laura; Cherry, Simon R
2012-10-21
In previous work we demonstrated the potential of positron emission tomography (PET) detectors with depth-of-interaction (DOI) encoding capability based on phosphor-coated crystals. A DOI resolution of 8 mm full-width at half-maximum was obtained for 20 mm long scintillator crystals using a delayed charge integration linear regression method (DCI-LR). Phosphor-coated crystals modify the pulse shape to allow continuous DOI information determination, but the relationship between pulse shape and DOI is complex. We are therefore interested in developing a sensitive and robust method to estimate the DOI. Here, linear discriminant analysis (LDA) was implemented to classify the events based on information extracted from the pulse shape. Pulses were acquired with 2×2×20 mm(3) phosphor-coated crystals at five irradiation depths and characterized by their DCI values or Laguerre coefficients. These coefficients were obtained by expanding the pulses on a Laguerre basis set and constituted a unique signature for each pulse. The DOI of individual events was predicted using LDA based on Laguerre coefficients (Laguerre-LDA) or DCI values (DCI-LDA) as discriminant features. Predicted DOIs were compared to true irradiation depths. Laguerre-LDA showed higher sensitivity and accuracy than DCI-LDA and DCI-LR and was also more robust to predict the DOI of pulses with higher statistical noise due to low light levels (interaction depths further from the photodetector face). This indicates that Laguerre-LDA may be more suitable to DOI estimation in smaller crystals where lower collected light levels are expected. This novel approach is promising for calculating DOI using pulse shape discrimination in single-ended readout depth-encoding PET detectors.
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Roncali, Emilie; Phipps, Jennifer E.; Marcu, Laura; Cherry, Simon R.
2012-01-01
In previous work we demonstrated the potential of positron emission tomography (PET) detectors with depth-of-interaction (DOI) encoding capability based on phosphor-coated crystals. A DOI resolution of 8 mm full-width at half-maximum was obtained for 20 mm long scintillator crystals using a delayed charge integration linear regression method (DCI-LR). Phosphor-coated crystals modify the pulse shape to allow continuous DOI information determination, but the relationship between pulse shape and DOI is complex. We are therefore interested in developing a sensitive and robust method to estimate the DOI. Here, linear discriminant analysis (LDA) was implemented to classify the events based on information extracted from the pulse shape. Pulses were acquired with 2 × 2 × 20 mm3 phosphor-coated crystals at five irradiation depths and characterized by their DCI values or Laguerre coefficients. These coefficients were obtained by expanding the pulses on a Laguerre basis set and constituted a unique signature for each pulse. The DOI of individual events was predicted using LDA based on Laguerre coefficients (Laguerre-LDA) or DCI values (DCI-LDA) as discriminant features. Predicted DOIs were compared to true irradiation depths. Laguerre-LDA showed higher sensitivity and accuracy than DCI-LDA and DCI-LR and was also more robust to predict the DOI of pulses with higher statistical noise due to low light levels (interaction depths further from the photodetector face). This indicates that Laguerre-LDA may be more suitable to DOI estimation in smaller crystals where lower collected light levels are expected. This novel approach is promising for calculating DOI using pulse shape discrimination in single-ended readout depth-encoding PET detectors. PMID:23010690
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43 CFR 17.336 - Hearings, decisions, post-termination proceedings.
Code of Federal Regulations, 2010 CFR
2010-10-01
...-termination proceedings. Certain DOI procedural provisions applicable to title VI of the Civil Rights Act of 1964 apply to DOI's enforcement of these regulations. The procedural provisions of DOI's Title VI...
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43 CFR 17.336 - Hearings, decisions, post-termination proceedings.
Code of Federal Regulations, 2011 CFR
2011-10-01
...-termination proceedings. Certain DOI procedural provisions applicable to title VI of the Civil Rights Act of 1964 apply to DOI's enforcement of these regulations. The procedural provisions of DOI's Title VI...
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Semi-transparent all-oxide ultraviolet light-emitting diodes based on ZnO/NiO-core/shell nanowires
NASA Astrophysics Data System (ADS)
Shi, Zhi-Feng; Xu, Ting-Ting; Wu, Di; Zhang, Yuan-Tao; Zhang, Bao-Lin; Tian, Yong-Tao; Li, Xin-Jian; Du, Guo-Tong
2016-05-01
Semi-transparent all-oxide light-emitting diodes based on ZnO/NiO-core/shell nanowire structures were prepared on double-polished c-Al2O3 substrates. The entire heterojunction diode showed an average transparency of ~65% in the ultraviolet and visible regions. Under forward bias, the diode displayed an intense ultraviolet emission at ~382 nm, and its electroluminescence performance was remarkable in terms of a low emission onset, acceptable operating stability, and the ability to optically excite emissive semiconductor nanoparticle chromophores.Semi-transparent all-oxide light-emitting diodes based on ZnO/NiO-core/shell nanowire structures were prepared on double-polished c-Al2O3 substrates. The entire heterojunction diode showed an average transparency of ~65% in the ultraviolet and visible regions. Under forward bias, the diode displayed an intense ultraviolet emission at ~382 nm, and its electroluminescence performance was remarkable in terms of a low emission onset, acceptable operating stability, and the ability to optically excite emissive semiconductor nanoparticle chromophores. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr07236k
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Jonckheere, Dries; Coutino-Gonzalez, Eduardo; Baekelant, Wouter; Bueken, Bart; Reinsch, Helge; Stassen, Ivo; Fenwick, Oliver; Richard, Fanny; Samorì, Paolo; Ameloot, Rob; Hofkens, Johan
2016-01-01
Bright luminescent silver-adenine species were successfully stabilized in the pores of the MOF-69A (zinc biphenyldicarboxylate) metal–organic framework, starting from the intrinsically blue luminescent bio-MOF-1 (zinc adeninate 4,4′-biphenyldicarboxylate). Bio-MOF-1 is transformed to the MOF-69A framework by selectively leaching structural adenine linkers from the original framework using silver nitrate solutions in aqueous ethanol. Simultaneously, bright blue-green luminescent silver-adenine clusters are formed inside the pores of the recrystallized MOF-69A matrix in high local concentrations. The structural transition and concurrent changes in optical properties were characterized using a range of structural, physicochemical and spectroscopic techniques (steady-state and time-resolved luminescence, quantum yield determination, fluorescence microscopy). The presented results open new avenues for exploring the use of MOFs containing luminescent silver clusters for solid-state lighting and sensor applications. PMID:28496980
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Optical design of an in vivo laparoscopic lighting system
NASA Astrophysics Data System (ADS)
Liu, Xiaolong; Abdolmalaki, Reza Yazdanpanah; Mancini, Gregory J.; Tan, Jindong
2017-12-01
This paper proposes an in vivo laparoscopic lighting system design to address the illumination issues, namely poor lighting uniformity and low optical efficiency, existing in the state-of-the-art in vivo laparoscopic cameras. The transformable design of the laparoscopic lighting system is capable of carrying purposefully designed freeform optical lenses for achieving lighting performance with high illuminance uniformity and high optical efficiency in a desired target region. To design freeform optical lenses for extended light sources such as LEDs with Lambertian light intensity distributions, we present an effective and complete freeform optical design method. The procedures include (1) ray map computation by numerically solving a standard Monge-Ampere equation; (2) initial freeform optical surface construction by using Snell's law and a lens volume restriction; (3) correction of surface normal vectors due to accumulated errors from the initially constructed surfaces; and (4) feedback modification of the solution to deal with degraded illuminance uniformity caused by the extended sizes of the LEDs. We employed an optical design software package to evaluate the performance of our laparoscopic lighting system design. The simulation results show that our design achieves greater than 95% illuminance uniformity and greater than 89% optical efficiency (considering Fresnel losses) for illuminating the target surgical region.
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Heterogeneous ice nucleation and phase transition of viscous α-pinene secondary organic aerosol
NASA Astrophysics Data System (ADS)
Ignatius, Karoliina; Kristensen, Thomas B.; Järvinen, Emma; Nichman, Leonid; Fuchs, Claudia; Gordon, Hamish; Herenz, Paul; Hoyle, Christopher R.; Duplissy, Jonathan; Baltensperger, Urs; Curtius, Joachim; Donahue, Neil M.; Gallagher, Martin W.; Kirkby, Jasper; Kulmala, Markku; Möhler, Ottmar; Saathoff, Harald; Schnaiter, Martin; Virtanen, Annele; Stratmann, Frank
2016-04-01
There are strong indications that particles containing secondary organic aerosol (SOA) exhibit amorphous solid or semi-solid phase states in the atmosphere. This may facilitate deposition ice nucleation and thus influence cirrus cloud properties. Global model simulations of monoterpene SOA particles suggest that viscous biogenic SOA are indeed present in regions where cirrus cloud formation takes place. Hence, they could make up an important contribution to the global ice nucleating particle (INP) budget. However, experimental ice nucleation studies of biogenic SOA are scarce. Here, we investigated the ice nucleation ability of viscous SOA particles at the CLOUD (Cosmics Leaving OUtdoor Droplets) experiment at CERN (Ignatius et al., 2015, Järvinen et al., 2015). In the CLOUD chamber, the SOA particles were produced from the ozone initiated oxidation of α-pinene at temperatures in the range from -38 to -10° C at 5-15 % relative humidity with respect to water (RHw) to ensure their formation in a highly viscous phase state, i.e. semi-solid or glassy. We found that particles formed and grown in the chamber developed an asymmetric shape through coagulation. As the RHw was increased to between 35 % at -10° C and 80 % at -38° C, a transition to spherical shape was observed with a new in-situ optical method. This transition confirms previous modelling of the viscosity transition conditions. The ice nucleation ability of SOA particles was investigated with a new continuous flow diffusion chamber SPIN (Spectrometer for Ice Nuclei) for different SOA particle sizes. For the first time, we observed heterogeneous ice nucleation of viscous α-pinene SOA in the deposition mode for ice saturation ratios between 1.3 and 1.4, significantly below the homogeneous freezing limit. The maximum frozen fractions found at temperatures between -36.5 and -38.3° C ranged from 6 to 20 % and did not depend on the particle surface area. References Ignatius, K. et al., Heterogeneous ice nucleation of secondary organic aerosol produced from ozonolysis of α-pinene, Atmos. Chem. Phys. Discuss., 15, 35719-35752, doi:10.5194/acpd-15-35719-2015, 2015. Järvinen, E. et al., Observation of viscosity transition in α-pinene secondary organic aerosol, Atmos. Chem. Phys. Discuss., 15, 28575-28617, doi:10.5194/acpd-15-28575-2015, 2015.
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43 CFR 2.34 - Where can I get a copy of DOI's FOIA annual report?
Code of Federal Regulations, 2010 CFR
2010-10-01
... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Where can I get a copy of DOI's FOIA... AND TESTIMONY; FREEDOM OF INFORMATION ACT FOIA Annual Report § 2.34 Where can I get a copy of DOI's FOIA annual report? Under 5 U.S.C. 552(e), DOI is required to prepare an annual report regarding its...
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Code of Federal Regulations, 2011 CFR
2011-01-01
... 2 Grants and Agreements 1 2011-01-01 2011-01-01 false Whom in the DOI does a recipient who is an individual notify about a criminal drug conviction? 1401.401 Section 1401.401 Grants and Agreements Federal... Whom in the DOI does a recipient who is an individual notify about a criminal drug conviction? The DOI...
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Developing Data Citations from Digital Object Identifier Metadata
NASA Technical Reports Server (NTRS)
James, Nathan; Wanchoo, Lalit
2015-01-01
NASA's Earth Science Data and Information System (ESDIS) Project has been processing information for the registration of Digital Object Identifiers (DOI) for the last five years of which an automated system has been in operation for the last two years. The ESDIS DOI registration system has registered over 2000 DOIs with over 1000 DOIs held in reserve until all required information has been collected. By working towards the goal of assigning DOIs to the 8000+ data collections under its management, ESDIS has taken the first step towards facilitating the use of data citations with those products. Jeanne Behnke, ESDIS Deputy Project Manager has reviewed and approved the poster.
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Doping of wide-bandgap titanium-dioxide nanotubes: optical, electronic and magnetic properties
NASA Astrophysics Data System (ADS)
Alivov, Yahya; Singh, Vivek; Ding, Yuchen; Cerkovnik, Logan Jerome; Nagpal, Prashant
2014-08-01
Doping semiconductors is an important step for their technological application. While doping bulk semiconductors can be easily achieved, incorporating dopants in semiconductor nanostructures has proven difficult. Here, we report a facile synthesis method for doping titanium-dioxide (TiO2) nanotubes that was enabled by a new electrochemical cell design. A variety of optical, electronic and magnetic dopants were incorporated into the hollow nanotubes, and from detailed studies it is shown that the doping level can be easily tuned from low to heavily-doped semiconductors. Using desired dopants - electronic (p- or n-doped), optical (ultraviolet bandgap to infrared absorption in co-doped nanotubes), and magnetic (from paramagnetic to ferromagnetic) properties can be tailored, and these technologically important nanotubes can be useful for a variety of applications in photovoltaics, display technologies, photocatalysis, and spintronic applications.Doping semiconductors is an important step for their technological application. While doping bulk semiconductors can be easily achieved, incorporating dopants in semiconductor nanostructures has proven difficult. Here, we report a facile synthesis method for doping titanium-dioxide (TiO2) nanotubes that was enabled by a new electrochemical cell design. A variety of optical, electronic and magnetic dopants were incorporated into the hollow nanotubes, and from detailed studies it is shown that the doping level can be easily tuned from low to heavily-doped semiconductors. Using desired dopants - electronic (p- or n-doped), optical (ultraviolet bandgap to infrared absorption in co-doped nanotubes), and magnetic (from paramagnetic to ferromagnetic) properties can be tailored, and these technologically important nanotubes can be useful for a variety of applications in photovoltaics, display technologies, photocatalysis, and spintronic applications. Electronic supplementary information (ESI) available: See DOI: 10.1039/c4nr02417f
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Ogata, Yuma; Ohnishi, Takashi; Moriya, Takahiro; Inadama, Naoko; Nishikido, Fumihiko; Yoshida, Eiji; Murayama, Hideo; Yamaya, Taiga; Haneishi, Hideaki
2014-01-01
The X'tal cube is a next-generation DOI detector for PET that we are developing to offer higher resolution and higher sensitivity than is available with present detectors. It is constructed from a cubic monolithic scintillation crystal and silicon photomultipliers which are coupled on various positions of the six surfaces of the cube. A laser-processing technique is applied to produce 3D optical boundaries composed of micro-cracks inside the monolithic scintillator crystal. The current configuration is based on an empirical trial of a laser-processed boundary. There is room to improve the spatial resolution by optimizing the setting of the laser-processed boundary. In fact, the laser-processing technique has high freedom in setting the parameters of the boundary such as size, pitch, and angle. Computer simulation can effectively optimize such parameters. In this study, to design optical characteristics properly for the laser-processed crystal, we developed a Monte Carlo simulator which can model arbitrary arrangements of laser-processed optical boundaries (LPBs). The optical characteristics of the LPBs were measured by use of a setup with a laser and a photo-diode, and then modeled in the simulator. The accuracy of the simulator was confirmed by comparison of position histograms obtained from the simulation and from experiments with a prototype detector composed of a cubic LYSO monolithic crystal with 6 × 6 × 6 segments and multi-pixel photon counters. Furthermore, the simulator was accelerated by parallel computing with general-purpose computing on a graphics processing unit. The calculation speed was about 400 times faster than that with a CPU.
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A Model for Data Citation in Astronomical Research Using Digital Object Identifiers (DOIs)
NASA Astrophysics Data System (ADS)
Novacescu, Jenny; Peek, Joshua E. G.; Weissman, Sarah; Fleming, Scott W.; Levay, Karen; Fraser, Elizabeth
2018-05-01
Standardizing and incentivizing the use of digital object identifiers (DOIs) to aggregate and identify both data analyzed and data generated by a research project will advance the field of astronomy to match best practices in other research fields like geoscience and medicine. An increase in the use of DOIs will prepare the discipline for changing expectations among funding agencies and publishers, who increasingly expect accurate and thorough data citation to accompany scientific outputs. The use of DOIs ensures a robust, sustainable, and interoperable approach to data citation in which due credit is given to the researchers and institutions who produce and maintain the primary data. We describe in this work the advantages of DOIs for data citation and best practices for integrating a DOI service in an astronomical archive. We report on a pilot project carried out in collaboration with AAS journals. During the course of the 1.5-year long pilot, over 75% of submitting authors opted to use the integrated DOI service to clearly identify data analyzed during their research project when prompted at the time of paper submission.
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Data always getting bigger -- A scalable DOI architecture for big and expanding scientific data
DOE Office of Scientific and Technical Information (OSTI.GOV)
Prakash, Giri; Shrestha, Biva; Younkin, Katarina
The Atmospheric Radiation Measurement (ARM) Data Archive established a data citation strategy based on Digital Object Identifiers (DOIs) for the ARM datasets in order to facilitate citing continuous and diverse ARM datasets in articles and other papers. This strategy eases the tracking of data provided as supplements to articles and papers. Additionally, it allows future data users and the ARM Climate Research Facility to easily locate the exact data used in various articles. Traditionally, DOIs are assigned to individual digital objects (a report or a data table), but for ARM datasets, these DOIs are assigned to an ARM data product.more » This eliminates the need for creating DOIs for numerous components of the ARM data product, in turn making it easier for users to manage and cite the ARM data with fewer DOIs. In addition, the ARM data infrastructure team, with input from scientific users, developed a citation format and an online data citation generation tool for continuous data streams. As a result, this citation format includes DOIs along with additional details such as spatial and temporal information.« less
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Data always getting bigger -- A scalable DOI architecture for big and expanding scientific data
Prakash, Giri; Shrestha, Biva; Younkin, Katarina; ...
2016-08-31
The Atmospheric Radiation Measurement (ARM) Data Archive established a data citation strategy based on Digital Object Identifiers (DOIs) for the ARM datasets in order to facilitate citing continuous and diverse ARM datasets in articles and other papers. This strategy eases the tracking of data provided as supplements to articles and papers. Additionally, it allows future data users and the ARM Climate Research Facility to easily locate the exact data used in various articles. Traditionally, DOIs are assigned to individual digital objects (a report or a data table), but for ARM datasets, these DOIs are assigned to an ARM data product.more » This eliminates the need for creating DOIs for numerous components of the ARM data product, in turn making it easier for users to manage and cite the ARM data with fewer DOIs. In addition, the ARM data infrastructure team, with input from scientific users, developed a citation format and an online data citation generation tool for continuous data streams. As a result, this citation format includes DOIs along with additional details such as spatial and temporal information.« less
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Marcinkowski, Radosław; Mollet, Pieter; Van Holen, Roel; Vandenberghe, Stefaan
2016-03-07
The mouse model is widely used in a vast range of biomedical and preclinical studies. Thanks to the ability to detect and quantify biological processes at the molecular level in vivo, PET has become a well-established tool in these investigations. However, the need to visualize and quantify radiopharmaceuticals in anatomic structures of millimetre or less requires good spatial resolution and sensitivity from small-animal PET imaging systems.In previous work we have presented a proof-of-concept of a dedicated high-resolution small-animal PET scanner based on thin monolithic scintillator crystals and Digital Photon Counter photosensor. The combination of thin monolithic crystals and MLE positioning algorithm resulted in an excellent spatial resolution of 0.7 mm uniform in the entire field of view (FOV). However, the limitation of the scanner was its low sensitivity due to small thickness of the lutetium-yttrium oxyorthosilicate (LYSO) crystals (2 mm).Here we present an improved detector design for a small-animal PET system that simultaneously achieves higher sensitivity and sustains a sub-millimetre spatial resolution. The proposed detector consists of a 5 mm thick monolithic LYSO crystal optically coupled to a Digital Photon Counter. Mean nearest neighbour (MNN) positioning combined with depth of interaction (DOI) decoding was employed to achieve sub-millimetre spatial resolution. To evaluate detector performance the intrinsic spatial resolution, energy resolution and coincidence resolving time (CRT) were measured. The average intrinsic spatial resolution of the detector was 0.60 mm full-width-at-half-maximum (FWHM). A DOI resolution of 1.66 mm was achieved. The energy resolution was 23% FWHM at 511 keV and CRT of 529 ps were measured. The improved detector design overcomes the sensitivity limitation of the previous design by increasing the nominal sensitivity of the detector block and retains an excellent intrinsic spatial resolution.
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Recent Developments in PET Instrumentation
Peng, Hao; Levin, Craig S.
2013-01-01
Positron emission tomography (PET) is used in the clinic and in vivo small animal research to study molecular processes associated with diseases such as cancer, heart disease, and neurological disorders, and to guide the discovery and development of new treatments. This paper reviews current challenges of advancing PET technology and some of newly developed PET detectors and systems. The paper focuses on four aspects of PET instrumentation: high photon detection sensitivity; improved spatial resolution; depth-of-interaction (DOI) resolution and time-of-flight (TOF). Improved system geometry, novel non-scintillator based detectors, and tapered scintillation crystal arrays are able to enhance the photon detection sensitivity of a PET system. Several challenges for achieving high resolution with standard scintillator-based PET detectors are discussed. Novel detectors with 3-D positioning capability have great potential to be deployed in PET for achieving spatial resolution better than 1 mm, such as cadmium-zinc-telluride (CZT) and position-sensitive avalanche photodiodes (PSAPDs). DOI capability enables a PET system to mitigate parallax error and achieve uniform spatial resolution across the field-of-view (FOV). Six common DOI designs, as well as advantages and limitations of each design, are discussed. The availability of fast scintillation crystals such as LaBr3, and the silicon photomultiplier (SiPM) greatly advances TOF-PET development. Recent instrumentation and initial results of clinical trials are briefly presented. If successful, these technology advances, together with new probe molecules, will substantially enhance the molecular sensitivity of PET and thus increase its role in preclinical and clinical research as well as evaluating and managing disease in the clinic. PMID:20497121
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NASA Astrophysics Data System (ADS)
Neary, Lori; Daerden, Frank
2013-04-01
GEM-Mars is a three-dimensional general circulation model of the Mars atmosphere extending from the surface to approximately 170 km based on the latest version of the GEM (Global Environmental Mesoscale) model, the operational data assimilation and weather forecasting system for Canada [Côté et al., 1998]. The dynamical core is an implicit two-time-level semi-Lagrangian scheme on an Arakawa C-grid with a terrain-following, log-hydrostatic-pressure vertical coordinate discretized on a Charney-Phillips grid. The model has both a hydrostatic and non-hydrostatic formulation, providing a single platform for simulations on a variety of horizontal scales. The model code is fully parallelized using OMP and MPI. The GCM includes the relevant physical processes such as CO2 condensation, planetary boundary layer mixing, gravity wave drag and surface parameterizations. A simple water cycle, basic gas-phase chemistry and passive tracers are also included in the model. Because of the vertical extent of the model, UV heating, non-LTE effects and molecular diffusion are also included. Dust is prescribed using the MGS scenario for total opacities and a Conrath profile shape. In the dust radiative transfer code, dust optical properties are based on the Wolff et al [2006, 2009] data. Temperatures in the lower and middle atmosphere have been evaluated using TES [Smith, 2004] and MCS [Kleinbohl et al. 2009] data. Winds and atmospheric circulation (mass stream functions) have been compared with the literature and show a good correspondence to other Mars GCMs. In parallel, active lifting and settling of size-distributed dust has also been implemented. The soil model has been improved to better match surface and near-surface temperatures from the Viking Landers, Phoenix [Davy et al. 2010], and TES. Near-surface winds and friction velocities have been compared with the literature and show reasonable performance. Condensation of CO2 in surface ice has been validated using CO2 ice mass data from HEND [Litvak et al. 2004] and GRS [Kelly et al. 2006]. The effect of the polar cap formation on the pressure cycle is found to be in very good agreement with the Viking Landers and Phoenix [Taylor et al. 2010] data. References: Côté J., S. Gravel, A. Méthot, A. Patoine, M. Roch and A. Staniforth, The operational CMC-MRB Global Environmental Multiscale (GEM) model: Part I - Design considerations and formulation, Mon. Wea. Rev., 126, 1373-1395. Davy, R., J. A. Davis, P. A. Taylor, C. F. Lange, W. Weng, J. Whiteway, and H. P. Gunnlaugson (2010), Initial analysis of air temperature and related data from the Phoenix MET station and their use in estimating turbulent heat fluxes, J. Geophys. Res., 115, E00E13, doi:10.1029/2009JE003444. Kelly, N. J., W. V. Boynton, K. Kerry, D. Hamara, D. Janes, R. C. Reedy, K. J. Kim, and R. M. Haberle (2006), Seasonal polar carbon dioxide frost on Mars: CO2 mass and columnar thickness distribution, J. Geophys. Res., 111, E03S07, doi:10.1029/2006JE002678 [printed 112(E3), 2007]. Kleinbohl, A., J. T. Schofield, D. M. Kass, W. A. Abdou, C. R. Backus, B. Sen, J. H. Shirley,W. G. Lawson, M. I. Richardson, F. W. Taylor, N. A. Teanby, and D. J. McCleese (2009). "Mars Climate Sounder limb profile retrieval of atmospheric temperature, pressure, dust and water ice opacity," J. Geophys. Res., 114, E10006, doi:10.1029/2009JE003358. Litvak, M. L., et al. (2004), Seasonal carbon dioxide depositions on the Martian surface as revealed from neutron measurements by the HEND instrument onboard the 2001 Mars Odyssey Spacecraft, Sol. Syst. Res., 38, 167 - 177. Smith M. D. (2004), Interannual variability in TES atmospheric observations of Mars during 1999-2003, Icarus 167, 148 -165. Taylor, P. A., et al. (2010), On pressure measurement and seasonal pressure variations during the Phoenix mission, J. Geophys. Res., 115, E00E15, doi:10.1029/2009JE003422. Wolff, M. J., et al. (2006), Constraints on dust aerosols from the Mars Exploration Rovers using MGS overflights and Mini-TES, J. Geophys. Res., 111, E12S17, doi:10.1029/2006JE002786 Wolff, M. J., M. D. Smith, R. T. Clancy, R. Arvidson, M. Kahre, F. Seelos, S. Murchie, and H. Savijärvi (2009), Wavelength dependence of dust aerosol single scattering albedo as observed by the Compact Reconnaissance Imaging Spectrometer, J. Geophys. Res., 114, E00D04, doi:10.1029/2009JE003350
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Optical design of an in vivo laparoscopic lighting system.
Liu, Xiaolong; Abdolmalaki, Reza Yazdanpanah; Mancini, Gregory J; Tan, Jindong
2017-12-01
This paper proposes an in vivo laparoscopic lighting system design to address the illumination issues, namely poor lighting uniformity and low optical efficiency, existing in the state-of-the-art in vivo laparoscopic cameras. The transformable design of the laparoscopic lighting system is capable of carrying purposefully designed freeform optical lenses for achieving lighting performance with high illuminance uniformity and high optical efficiency in a desired target region. To design freeform optical lenses for extended light sources such as LEDs with Lambertian light intensity distributions, we present an effective and complete freeform optical design method. The procedures include (1) ray map computation by numerically solving a standard Monge-Ampere equation; (2) initial freeform optical surface construction by using Snell's law and a lens volume restriction; (3) correction of surface normal vectors due to accumulated errors from the initially constructed surfaces; and (4) feedback modification of the solution to deal with degraded illuminance uniformity caused by the extended sizes of the LEDs. We employed an optical design software package to evaluate the performance of our laparoscopic lighting system design. The simulation results show that our design achieves greater than 95% illuminance uniformity and greater than 89% optical efficiency (considering Fresnel losses) for illuminating the target surgical region. (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).
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Bison conservation initiative: Bison conservation genetics workshop: report and recommendations
Gogan, Peter J.; Dratch, Peter
2010-01-01
One of the first outcomes of the Department of the Interior (DOI) Bison Conservation Initiative was the Bison Conservation Genetics Workshop held in Nebraska in September 2008. The workshop brought together scientists from government agencies and non-governmental organizations with professional population geneticists to develop guidance for the genetic management of the federal bison herds. The scientists agreed on the basic tenets of genetic management for the DOI herds and discussed different approaches to meeting those goals. First, the 12 DOI herds are an irreplaceable resource for the long-term conservation of North American plains bison. Most of the herds show low levels of cattle introgression dating from the time when they were saved from extirpation; those herds should not be mixed without careful consideration as to their origin. Herds that show no evidence of cattle ancestry by the current molecular methods are the highest priority for protection from genetic mixing with any other bison herds. Second, despite the fact that most of the herds now managed by the U.S. government were founded with very few bison and have been maintained for many generations at relatively low population sizes, they do not show obvious effects of inbreeding. They have retained significant amounts of genetic variation by the standard measures, heterozygosity and allelic diversity. This may be explained in part by the fact that most of these herds are not remnants of a single population. Third, to preserve genetic variation in federal bison herds over decades and centuries, herds should be managed at a population or metapopulation level of 1,000 animals or more, with a sex ratio that enables competition between breeding bulls. The parks and refuges that currently have bison herds, with the exception of Yellowstone National Park, do not have enough land to support a population of this size. In the short term, it will be important to develop satellite herds to attain population targets, and develop a metapopulation structure between herds. Fourth and finally, the current methods used to evaluate the DOI bison herds, using mitochondrial DNA and a suite of nuclear DNA microsatellites, are highly informative at the herd level. They have confirmed relatedness of herds that we know from historical records have a common origin. They have detected cattle ancestry in most of the herds where it was suspected and have shown some loss of rare alleles. However, they do not sample across the bison genome, and the use of neutral genetic markers as the basis for selection of individual bison—either to breed or move to other herds—would be better supported by more high-resolution molecular methods currently under development.
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3-ω damage threshold evaluation of final optics components using Beamlet Mule and off-line testing
NASA Astrophysics Data System (ADS)
Kozlowski, Mark R.; Maricle, Stephen M.; Mouser, Ron P.; Schwartz, Sheldon; Wegner, Paul J.; Weiland, Timothy L.
1999-07-01
A statistics-based model is being develop to predict the laser-damage-limited lifetime of UV optical components on the NIF laser. In order to provide data for the mode, laser damage experiments were performed on the Beamlet laser system at LLNL. An early protoype NIF focus lens was exposed to twenty 351 nm pulses at an average fluence of 5 J/cm2, 3ns. Using a high resolution optic inspection inspection system a total of 353 damage sites was detected within the 1160 cm2 beam aperture. Through inspections of the lens before, after and, in some cases, during the campaign, pulse to pulse damage growth rates were measured for damage initiating both on the surface and at bulk inclusions. Growth rates as high as 79 micrometers /pulse were observed for damage initiating at pre-existing scratches in the surface. For most damage sites on the optic, both on the surface and at bulk inclusions. Growth rates as high as 79 micrometers /pulse were observed for damage initiating at per- existing scratches in the surface. For most damage sites on the optic, both surface and bulk, the damage growth rate was approximately 10(Mu) m/pulse.
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Code of Federal Regulations, 2011 CFR
2011-01-01
... 2 Grants and Agreements 1 2011-01-01 2011-01-01 false Whom in the DOI does a recipient other than... Individuals § 1401.335 Whom in the DOI does a recipient other than an individual notify about a criminal drug conviction? The DOI is not designating a central location for the receipt of these reports. Therefore you...
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Chen, Jie; Koswatta, Panduka; DeBergh, J. Robb; Fu, Peng; Pan, Ende
2015-01-01
Nigricanoside A was isolated from green alga, and its dimethyl ester was found to display potent cytotoxicity. Its scarcity prevented a full structure elucidation, leaving total synthesis as the only means to determine its relative and absolute stereochemistry and to explore its biological activity. Here we assign the stereochemistry of the natural product through enantioselective total synthesis and provide initial studies of its cytotoxicity. PMID:26877863
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NASA Astrophysics Data System (ADS)
Ngwira, Chigomezyo M.; Pulkkinen, Antti; Kuznetsova, Maria M.; Glocer, Alex
2018-02-01
In this response, we address the three main comments by Tsurutani et al. (2018, http://doi.org/10.1002/2017JA024779) namely, unusually high plasma density, interplanetary magnetic field intensity, and fast storm recovery phase. The authors agree that there is room to improve the modeling by taking into account these comments and other aspects that were not fully explored during our initial work. We are already in the process of undertaking a more comprehensive modeling project.
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Terminal navigation analysis for the 1980 comet Encke slow flyby mission
NASA Technical Reports Server (NTRS)
Jacobson, R. A.; Mcdanell, J. P.; Rinker, G. C.
1973-01-01
The initial results of a terminal navigation analysis for the proposed 1980 solar electric slow flyby mission to the comet Encke are presented. The navigation technique employs onboard optical measurements with the scientific television camera, groundbased observations of the spacecraft and comet, and groundbased orbit determination and thrust vector update computation. The knowledge and delivery accuracies of the spacecraft are evaluated as a function of the important parameters affecting the terminal navigation. These include optical measurement accuracy, thruster noise level, duration of the planned terminal coast period, comet ephemeris uncertainty, guidance initiation time, guidance update frequency, and optical data rate.
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Smart window using a thermally and optically switchable liquid crystal cell
NASA Astrophysics Data System (ADS)
Oh, Seung-Won; Kim, Sang-Hyeok; Baek, Jong-Min; Yoon, Tae-Hoon
2018-02-01
Light shutter technologies that can control optical transparency have been studied extensively for developing curtain-free smart windows. We introduce thermally and optically switchable light shutters using LCs doped with push-pull azobenzene, which is known to speed up thermal relaxation. The liquid crystal light shutter can be switched between translucent and transparent states or transparent and opaque states by phase transition through changing temperature or photo-isomerization of doped azobenzene. The liquid crystal light shutter can be used for privacy windows with an initial translucent state or energy-saving windows with an initial transparent state.
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Depth of interaction determination in monolithic scintillator with double side SiPM readout.
Morrocchi, Matteo; Ambrosi, Giovanni; Bisogni, Maria Giuseppina; Bosi, Filippo; Boretto, Marco; Cerello, Piergiorgio; Ionica, Maria; Liu, Ben; Pennazio, Francesco; Piliero, Maria Antonietta; Pirrone, Giovanni; Postolache, Vasile; Wheadon, Richard; Del Guerra, Alberto
2017-12-01
Monolithic scintillators read out by arrays of photodetectors represent a promising solution to obtain high spatial resolution and the depth of interaction (DOI) of the annihilation photon. We have recently investigated a detector geometry composed of a monolithic scintillator readout on two sides by silicon photomultiplier (SiPM) arrays, and we have proposed two parameters for the DOI determination: the difference in the number of triggered SiPMs on the two sides of the detector and the difference in the maximum collected signal on a single SiPM on each side. This work is focused on the DOI calibration and on the determination of the capability of our detector. For the DOI calibration, we studied a method which can be implemented also in detectors mounted in a full PET scanner. We used a PET detector module composed of a monolithic 20 × 20 × 10 mm 3 LYSO scintillator crystal coupled on two opposite faces to two arrays of SiPMs. On each side, the scintillator was coupled to 6 × 6 SiPMs. In this paper, the two parameters previously proposed for the DOI determination were calibrated with two different methods. The first used a lateral scan of the detector with a collimated 511 keV pencil beam at steps of 0.5 mm to study the detector DOI capability, while the second used the background radiation of the 176 Lu in the scintillator. The DOI determination capability was tested on different regions of the detector using each parameter and the combination of the two. With both parameters for the DOI determination, in the lateral scan, the bias between the mean reconstructed DOI and the real beam position was lower than 0.3 mm, and the DOI distribution had a standard deviation of about 1.5 mm. When using the calibration with the radioactivity of the LYSO, the mean bias increased of about 0.2 mm but with no degradation of the standard deviation of the DOI distribution. The two parameters allow to achieve a DOI resolution comparable with the state of the art, giving a continuous information about the three-dimensional interaction position of the scintillation. These results were obtained by using simple estimators and a detector scalable to a whole PET system. The DOI calibration obtained using lutetium natural radioactivity gives results comparable to the other standard method but appears more readily applicable to detectors mounted in a full PET scanner.
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DOT National Transportation Integrated Search
2012-07-01
For this study, a novel optical fiber sensing system was developed and tested for the monitoring of corrosion in : transportation systems. The optical fiber sensing system consists of a reference long period fiber gratings (LPFG) sensor : for corrosi...
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Hydrogen gas storage in fluorinated ultramicroporous tunnel crystal
NASA Astrophysics Data System (ADS)
Kataoka, Keisuke; Katagiri, Toshimasa
2012-07-01
We report hydrogen storage at an ordinary pressure due to a bottle-neck effect of an ultramicroporous crystal. Stored hydrogen was kept at an ordinary pressure below -110 °C. The amounts of stored hydrogen gas linearly correlated with the initial pressures. These phenomena suggested the ultramicroporous tunnels worked as a molecular gas cylinder.We report hydrogen storage at an ordinary pressure due to a bottle-neck effect of an ultramicroporous crystal. Stored hydrogen was kept at an ordinary pressure below -110 °C. The amounts of stored hydrogen gas linearly correlated with the initial pressures. These phenomena suggested the ultramicroporous tunnels worked as a molecular gas cylinder. Electronic supplementary information (ESI) available. CCDC 246922. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c2nr30940h
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NASA Astrophysics Data System (ADS)
Wood, Claire M.; Bunce, Robert G. H.; Norton, Lisa R.; Maskell, Lindsay C.; Smart, Simon M.; Scott, W. Andrew; Henrys, Peter A.; Howard, David C.; Wright, Simon M.; Brown, Michael J.; Scott, Rod J.; Stuart, Rick C.; Watkins, John W.
2018-04-01
The Countryside Survey (CS) of Great Britain (GB) provides a unique and statistically robust series of datasets, consisting of an extensive set of repeated ecological measurements at a national scale, covering a time span of 29 years. CS was first undertaken in 1978 to provide a baseline for ecological and land use change monitoring in the rural environment of GB, following a stratified random design, based on 1 km squares. Originally, eight random 1 km squares were drawn from each of 32 environmental classes, thus comprising 256 sample squares in the 1978 survey. The number of these sites increased to 382 in 1984, 506 in 1990, 569 in 1998 and 591 in 2007. Detailed information regarding vegetation types and land use was mapped in all five surveys, allowing reporting by defined standard habitat classifications. Additionally, point and linear landscape features (such as trees and hedgerows) are available from all surveys after 1978. From these stratified, randomly located sample squares, information can be converted into national estimates, with associated error terms. Other data, relating to soils, freshwater and vegetation, were also sampled on analogous dates. However, the present paper describes only the surveys of landscape features and habitats. The resulting datasets provide a unique, comprehensive, quantitative ecological coverage of extent and change in these features in GB. Basic results are presented and their implications discussed. However, much opportunity for further analyses remains. Data from each of the survey years are available via the following DOIs: Landscape area data 1978: https://doi.org/10.5285/86c017ba-dc62-46f0-ad13-c862bf31740e, 1984: https://doi.org/10.5285/b656bb43-448d-4b2c-aade-7993aa243ea3, 1990: https://doi.org/10.5285/94f664e5-10f2-4655-bfe6-44d745f5dca7, 1998: https://doi.org/10.5285/1e050028-5c55-42f4-a0ea-c895d827b824, and 2007: https://doi.org/10.5285/bf189c57-61eb-4339-a7b3-d2e81fdde28d; Landscape linear feature data 1984: https://doi.org/10.5285/a3f5665c-94b2-4c46-909e-a98be97857e5, 1990: https://doi.org/10.5285/311daad4-bc8c-485a-bc8a-e0d054889219, 1998: https://doi.org/10.5285/8aaf6f8c-c245-46bb-8a2a-f0db012b2643 and 2007: https://doi.org/10.5285/e1d31245-4c0a-4dee-b36c-b23f1a697f88, Landscape point feature data 1984: https://doi.org/10.5285/124b872e-036e-4dd3-8316-476b5f42c16e, 1990: https://doi.org/10.5285/1481bc63-80d7-4d18-bcba-8804aa0a9e1b, 1998: https://doi.org/10.5285/ed10944f-40c8-4913-b3f5-13c8e844e153 and 2007: https://doi.org/10.5285/55dc5fd7-d3f7-4440-b8a7-7187f8b0550b.
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NASA Astrophysics Data System (ADS)
Nadkarni, Seemantini K.
2013-12-01
During the pathogenesis of coronary atherosclerosis, from lesion initiation to rupture, arterial mechanical properties are altered by a number of cellular, molecular, and hemodynamic processes. There is growing recognition that mechanical factors may actively drive vascular cell signaling and regulate atherosclerosis disease progression. In advanced plaques, the mechanical properties of the atheroma influence stress distributions in the fibrous cap and mediate plaque rupture resulting in acute coronary events. This review paper explores current optical technologies that provide information on the mechanical properties of arterial tissue to advance our understanding of the mechanical factors involved in atherosclerosis development leading to plaque rupture. The optical approaches discussed include optical microrheology and traction force microscopy that probe the mechanical behavior of single cell and extracellular matrix components, and intravascular imaging modalities including laser speckle rheology, optical coherence elastography, and polarization-sensitive optical coherence tomography to measure the mechanical properties of advanced coronary lesions. Given the wealth of information that these techniques can provide, optical imaging modalities are poised to play an increasingly significant role in elucidating the mechanical aspects of coronary atherosclerosis in the future.
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RETRACTED: Adaptive neuro-fuzzy prediction of modulation transfer function of optical lens system
NASA Astrophysics Data System (ADS)
Petković, Dalibor; Shamshirband, Shahaboddin; Anuar, Nor Badrul; Md Nasir, Mohd Hairul Nizam; Pavlović, Nenad T.; Akib, Shatirah
2014-07-01
This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor. Sections ;1. Introduction; and ;2. Modulation transfer function;, as well as Figures 1-3, plagiarize the article published by N. Gül and M. Efe in Turk J Elec Eng & Comp Sci 18 (2010) 71 (http://journals.tubitak.gov.tr/elektrik/issues/elk-10-18-1/elk-18-1-6-0811-9.pdf). Sections ;4. Adaptive neuro-fuzzy inference system; and ;6. Conclusion; duplicate parts of the articles previously published by the corresponding author et al in ;Expert Systems with Applications; 39 (2012) 13295-13304, http://dx.doi.org/10.1016/j.eswa.2012.05.072 and ;Expert Systems with Applications; 40 (2013) 281-286, http://dx.doi.org/10.1016/j.eswa.2012.07.076. One of the conditions of submission of a paper for publication is that authors declare explicitly that the paper is not under consideration for publication elsewhere. Re-use of any data should be appropriately cited. As such this article represents an abuse of the scientific publishing system. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process.
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The Aerosol Coarse Mode Initiative
NASA Astrophysics Data System (ADS)
Arnott, W. P.; Adhikari, N.; Air, D.; Kassianov, E.; Barnard, J.
2014-12-01
Many areas of the world show an aerosol volume distribution with a significant coarse mode and sometimes a dominant coarse mode. The large coarse mode is usually due to dust, but sea salt aerosol can also play an important role. However, in many field campaigns, the coarse mode tends to be ignored, because it is difficult to measure. This lack of measurements leads directly to a concomitant "lack of analysis" of this mode. Because, coarse mode aerosols can have significant effects on radiative forcing, both in the shortwave and longwave spectrum, the coarse mode -- and these forcings -- should be accounted for in atmospheric models. Forcings based only on fine mode aerosols have the potential to be misleading. In this paper we describe examples of large coarse modes that occur in areas of large aerosol loading (Mexico City, Barnard et al., 2010) as well as small loadings (Sacramento, CA; Kassianov et al., 2012; and Reno, NV). We then demonstrate that: (1) the coarse mode can contribute significantly to radiative forcing, relative to the fine mode, and (2) neglecting the coarse mode may result in poor comparisons between measurements and models. Next we describe -- in general terms -- the limitations of instrumentation to measure the coarse mode. Finally, we suggest a new initiative aimed at examining coarse mode aerosol generation mechanisms; transport and deposition; chemical composition; visible and thermal IR refractive indices; morphology; microphysical behavior when deposited on snow and ice; and specific instrumentation needs. Barnard, J. C., J. D. Fast, G. Paredes-Miranda, W. P. Arnott, and A. Laskin, 2010: Technical Note: Evaluation of the WRF-Chem "Aerosol Chemical to Aerosol Optical Properties" Module using data from the MILAGRO campaign, Atmospheric Chemistry and Physics, 10, 7325-7340. Kassianov, E. I., M. S. Pekour, and J. C. Barnard, 2012: Aerosols in Central California: Unexpectedly large contribution of coarse mode to aerosol radiative forcing, Geophys. Res. Lett., 39, L20806, doi:10.1029/2012GL053469.
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43 CFR 2.34 - Where can I get a copy of DOI's FOIA annual report?
Code of Federal Regulations, 2011 CFR
2011-10-01
... 43 Public Lands: Interior 1 2011-10-01 2011-10-01 false Where can I get a copy of DOI's FOIA annual report? 2.34 Section 2.34 Public Lands: Interior Office of the Secretary of the Interior RECORDS AND TESTIMONY; FREEDOM OF INFORMATION ACT FOIA Annual Report § 2.34 Where can I get a copy of DOI's FOIA annual report? Under 5 U.S.C. 552(e), DOI is...
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Evolving a NASA Digital Object Identifiers System with Community Engagement
NASA Astrophysics Data System (ADS)
Wanchoo, L.; James, N.
2016-12-01
In 2010, NASA's Earth Science Data and Information System (ESDIS) Project began investigating the assignment of unique identifiers to its suite of data products being stewarded at data centers distributed across the country. This process led to the use of Digital Object Identifiers (DOIs) and the development of an automated system for the registration of these DOIs. Since that time, the ESDIS DOI registration system has evolved to be fully functional with over 3000 publicly accessible DOIs and over 1000 being held in reserve status until the information required for registration is obtained. The goal is to assign DOIs to the entire 7000+ data collections under ESDIS management via its network of discipline-oriented data centers. A key factor in the successful evolution of the DOI registration system has been the incorporation of community input. Over the last 3 years, ESDIS has solicited community input for making the DOI registration process more efficient through three focus groups under NASA's Earth Science Data System Working Group (ESDSWG). These groups were largely composed of DOI submitters and data curators from the 12 data centers serving user communities of various science disciplines. The suggestions from these groups were formulated into recommendations for ESDIS consideration and implementation. This poster will describe the process and the activities of each focus group, their recommendations, and how these recommendations were implemented.
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Digital Object Identifiers for NASA's Earth Observing System Products
NASA Astrophysics Data System (ADS)
Moses, J. F.; James, N.
2012-12-01
The science community has long recognized the importance of citing data in published literature to encourage replication of experiments and verification of results. Authors that try to cite their data often find that publishers will not accept Internet addresses because they are viewed as transient references, frequently changed by the data provider after the paper is published. Digital Object Identifiers (DOIs) and the DOI® System were created to avoid this problem by providing a unique and persistent identifier scheme and an online resolution service. DOIs and the Internet service provided by the DOI System have emerged as the most acceptable scheme for publishers. NASA's Earth Science Data and Information System (ESDIS) Project, in cooperation with several Earth Observing System (EOS) instrument teams and data providers, has developed methods for assigning DOIs to EOS products. By assigning DOIs we are enabling authors and publishers to find it easier and more compelling to cite EOS data products. DOIs are unique alphanumeric strings that consist of a prefix and suffix. The prefix is assigned by a registration agency for the DOI System. The suffix must be unique, but is otherwise free to be constructed by the publisher, in this case NASA ESDIS Project. A strategy was needed for constructing DOI suffix names that corresponds to each EOS product. Since the onset of the DOI System, publishers have developed conventions to suit their own purposes. These range from random generation to complex, formally controlled vocabularies. An overarching ESDIS goal has been for the DOI names to be attractive for researchers to use in publication applications. Keeping them short and simple is paramount. When adding meaning to the string, it is also important that the name only refer to the data and not to the publisher, so that the DOI can be accepted as persistent even if the data is moved to a new publisher. Most users download EOS product files to their local facilities when they want to use the data for analysis or applications. By imbedding DOIs in the file metadata, users have access to the DOI value long after the product has left the source data center. This enables users to find documentation about the product in the future - long after it has left the contextual environment of the data provider. Existing HDF and netCDF metadata structures have been adapted to accommodate the addition of DOIs. In addition, associated EOSDIS core metadata will also contain a product specific attribute for DOIs. Advances in computer science and Internet brought about a host of data identification schemes designed to solve problems inherent in developing advanced provenance models. Lessons from trying to use early satellite observations in climate studies today point to the importance of providing links in data archives to documentation and publications about the data. Data system engineers link data records to standard product documentation prepared at the time of the mission and archive with the data, but will need to add links to the whole range of information needed to support future research and long-term climate studies. DOIs can serve this need if referenced by developers when preparing technical data and reports, as well as when publishing research results.
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Zorn-Kruppa, Michaela; Houdek, Pia; Wladykowski, Ewa; Engelke, Maria; Bartok, Melinda; Mewes, Karsten R.; Moll, Ingrid; Brandner, Johanna M.
2014-01-01
The depth of injury (DOI) is a mechanistic correlate to the ocular irritation response. Attempts to quantitatively determine the DOI in alternative tests have been limited to ex vivo animal eyes by fluorescent staining for biomarkers of cell death and viability in histological cross sections. It was the purpose of this study to assess whether DOI could also be measured by means of cell viability detected by the MTT assay using 3-dimensional (3D) reconstructed models of cornea and conjunctiva. The formazan-free area of metabolically inactive cells in the tissue after topical substance application is used as the visible correlate of the DOI. Areas of metabolically active or inactive cells are quantitatively analyzed on cryosection images with ImageJ software analysis tools. By incorporating the total tissue thickness, the relative MTT-DOI (rMTT-DOI) was calculated. Using the rMTT-DOI and human reconstructed cornea equivalents, we developed a prediction model based on suitable viability cut-off values. We tested 25 chemicals that cover the whole range of eye irritation potential based on the globally harmonized system of classification and labelling of chemicals (GHS). Principally, the MTT-DOI test method allows distinguishing between the cytotoxic effects of the different chemicals in accordance with all 3 GHS categories for eye irritation. Although the prediction model is slightly over-predictive with respect to non-irritants, it promises to be highly valuable to discriminate between severe irritants (Cat. 1), and mild to moderate irritants (Cat. 2). We also tested 3D conjunctiva models with the aim to specifically address conjunctiva-damaging substances. Using the MTT-DOI method in this model delivers comparable results as the cornea model, but does not add additional information. However, the MTT-DOI method using reconstructed cornea models already provided good predictability that was superior to the already existing established in vitro/ex vivo methods. PMID:25494045
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A Data Model and Task Space for Data of Interest (DOI) Eye-Tracking Analyses.
Jianu, Radu; Alam, Sayeed Safayet
2018-03-01
Eye-tracking data is traditionally analyzed by looking at where on a visual stimulus subjects fixate, or, to facilitate more advanced analyses, by using area-of-interests (AOI) defined onto visual stimuli. Recently, there is increasing interest in methods that capture what users are looking at rather than where they are looking. By instrumenting visualization code that transforms a data model into visual content, gaze coordinates reported by an eye-tracker can be mapped directly to granular data shown on the screen, producing temporal sequences of data objects that subjects viewed in an experiment. Such data collection, which is called gaze to object mapping (GTOM) or data-of-interest analysis (DOI), can be done reliably with limited overhead and can facilitate research workflows not previously possible. Our paper contributes to establishing a foundation of DOI analyses by defining a DOI data model and highlighting its differences to AOI data in structure and scale; by defining and exemplifying a space of DOI enabled tasks; by describing three concrete examples of DOI experimentation in three different domains; and by discussing immediate research challenges in creating a framework of visual support for DOI experimentation and analysis.
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Neutral Silicon-Vacancy Center in Diamond: Spin Polarization and Lifetimes
NASA Astrophysics Data System (ADS)
Green, B. L.; Mottishaw, S.; Breeze, B. G.; Edmonds, A. M.; D'Haenens-Johansson, U. F. S.; Doherty, M. W.; Williams, S. D.; Twitchen, D. J.; Newton, M. E.
2017-09-01
We demonstrate optical spin polarization of the neutrally charged silicon-vacancy defect in diamond (SiV0 ), an S =1 defect which emits with a zero-phonon line at 946 nm. The spin polarization is found to be most efficient under resonant excitation, but nonzero at below-resonant energies. We measure an ensemble spin coherence time T2>100 μ s at low-temperature, and a spin relaxation limit of T1>25 s . Optical spin-state initialization around 946 nm allows independent initialization of SiV0 and NV- within the same optically addressed volume, and SiV0 emits within the telecoms down-conversion band to 1550 nm: when combined with its high Debye-Waller factor, our initial results suggest that SiV0 is a promising candidate for a long-range quantum communication technology.
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NASA Astrophysics Data System (ADS)
Wendt, Harry; Orchiston, Wayne; Slee, Bruce
During the 1950s Australia was one of the world's foremost astronomical nations owing primarily to the work of the dynamic radio astronomy group within the Commonwealth Scientific and Industrial Research Organisation's Division of Radiophysics. Most of the observations were made at the network of field stations maintained by the Division in or near Sydney, and one of these field stations was Murraybank in the north-western suburbs of Sydney.
G Vaucouleurs De 1954 The Magellanic Clouds and the Galaxy The Observatory 74 23 31 1954Obs....74...23D De Vaucouleurs, G., 1954a. The Magellanic Clouds and the Galaxy. The Observatory, 74, 23-31. G Vaucouleurs De 1954 The Magellanic Clouds and the Galaxy, II The Observatory 74 158 164 1954Obs....74..158D De Vaucouleurs, G., 1954b. The Magellanic Clouds and the Galaxy, II. The Observatory, 74, 158-164. G Vaucouleurs De 1961 Classification and radial velocities of bright southern galaxies Memoirs of the Royal Astronomical Society 68 69 87 1961MmRAS..68...69D De Vaucouleurs, G., 1961. Classification and radial velocities of bright southern galaxies. Memoirs of the Royal Astronomical Society, 68, 69-87. J Deane 2006 Vacuum Tube Supercomputer Sydney Science Foundation for Physics and the Australian Computer Museum Society Deane, J., 2006. Vacuum Tube Supercomputer. Sydney, Science Foundation for Physics and the Australian Computer Museum Society. NH Deiter 1965 Neutral hydrogen near the galactic poles Ast Erickson, W.C., Helfer, H.L., and Tatel, H.E., 1959. A survey of neutral hydrogen at high galactic latitudes. In Bracewell, 390-397. MW Feast AD Thackeray AJ Wesselink 1957 Radial velocities of southern B stars determined at the Radcliffe Observatory (Paper II) (summary) Monthly Notices of the Royal Astronomical Society 117 579 1957MNRAS.117..579F Feast, M.W., Thackeray, A.D., and Wesselink, A.J., 1957. Radial velocities of southern B stars determined at the Radcliffe Observatory (Paper II) (summary). Monthly Notices of the Royal Astronomical Society, 117, 579. KC Freeman 1970 On the disks of spiral and SO galaxies Astrophysical Journal 160 811 830 1970ApJ...160..811F 10.1086/150474 Freeman, K.C., 1970. On the disks of spiral and SO galaxies. Astrophysical Journal, 160, 811-830. Getmanzev, G.G., Tankevitch, K.S., and Troitzky, V.S., 1957. Detection of the spectral line of deuterium from the centre of the Galaxy on the wave-length of 91.6 cm. In van de Hulst, 90-91. HC Goldwire M Goss 1967 Microwave radiation of singly charged helium 3 from HII regions Astrophysical Journal 149 15 22 1967ApJ...149...15G 10.1086/149225 Goldwire, H.C., and Goss, M., 1967. Microwave radiation of singly charged helium 3 from HII regions. Astrophysical Journal, 149, 15-22. JL Greenstein 1937 The effect of absorbing clouds on the general absorption coefficient Annals of the Astronomical Observatory of Harvard College 105 359 369 Greenstein, J.L., 1937. The effect of absorbing clouds on the general absorption coefficient. Annals of the Astronomical Observatory of Harvard College, 105, 359-369. CS Gum 1956 The extent and excitation of the large H II region in Vela-Puppis The Observatory 76 150 153 1956Obs....76..150G Gum, C.S., 1956. The extent and excitation of the large H II region in Vela-Puppis. The Observatory, 76, 150-153. KG Henize 1956 Catalogues of Hα-emission stars and nebulae in the Magellanic Clouds Astrophysical Journal Supplement 2 315 344 1956ApJS....2..315H 10.1086/190025 Henize, K.G., 1956. Catalogues of Hα-emission stars and nebulae in the Magellanic Clouds. Astrophysical Journal Supplement, 2, 315-344. JV Hindman 1967 A high resolution study of the distribution and motions of neutral hydrogen in the Small Cloud of Magellan Australian Journal of Physics 20 147 171 1967AuJPh..20..147H 10.1071/PH670147 Hindman, J.V., 1967. A high resolution study of the distribution and motions of neutral hydrogen in the Small Cloud of Magellan. Australian Journal of Physics, 20, 147-171. Hindman, J.V., Kerr, F.J., and McGee, R.X., 1963a. A low resolution hydrogen-line survey of the Magellanic system. II. Interpretation of results. Australian Journal of Physics, 16, 570-583. Hindman, J.V., McGee, R.X., Carter, A.W.L., Holmes, E.C.J., and Beard, M., 1963b. A low resolution hydrogen-line survey of the Magellanic system. I. Observations and digital reduction procedures. Australian Journal of Physics, 16, 552-569. Hodge, P.W., 1960. Studies of the Large Magellanic Cloud. I. The red globular clusters. Astrophysical Journal, 131, 351-357. Hodge, P.W., 1961. Studies of the Large Magellanic Cloud. V. The young populous clusters. Astrophysical Journal, 133, 413-419. WE Howard DG Wentzel RX McGee 1963 On a correlation between the radial velocities of optical and radio interstellar lines Astrophysical Journal 138 988 1001 1963ApJ...138..988H 10.1086/147700 Howard, W.E., Wentzel, D.G., and McGee, R.X., 1963. On a correlation between the radial velocities of optical and radio interstellar lines. Astrophysical Journal, 138, 988-1001. HM Johnson 1961 The structure of the Small Magellanic Cloud Proceedings of the Astronomical Society of the Pacific 73 20 28 1961PASP...73...20J 10.1086/127613 Johnson, H.M., 1961. The structure of the Small Magellanic Cloud. Proceedings of the Astronomical Society of the Pacific, 73, 20-28. KI Kellerman W Orchiston B Slee 2005 Gordon James Stanley and the early development of radio astronomy in Australia and the United States Publications of the Astronomical Society of Australia 22 13 23 2005PASA...22...13K 10.1071/AS04008 Kellerman, K.I., Orchiston, W., and Slee, B., 2005. Gordon James Stanley and the early development of radio astronomy in Australia and the United States. Publications of the Astronomical Society of Australia, 22, 13-23. Kerr, F.J., 1953. Minutes of the Hydrogen-Line Planning Committee Meeting dated 12 November. National Archives of Australia, Sydney, 972420 - C3830 - A1/3/17 Part 1. Kerr, F.J., 1954. Minutes of the Hydrogen Line Planning Committee Meeting dated 9 June. National Archives of Australia, Sydney, 972420 - C3830 - A1/3/17 Part 2. FJ Kerr 1962 Galactic velocity models and the interpretation of 21-cm surveys Monthly Notices of the Royal Astronomical Society 123 327 345 1962MNRAS.123..327K Kerr, F.J., 1962. Galactic velocity models and the interpretation of 21-cm surveys. Monthly Notices of the Royal Astronomical Society, 123, 327-345. FJ Kerr JV Hindman BJ Robinson 1954 Observations of the 21 cm line from the Magellanic Clouds Australian Journal of Physics 7 297 314 1954AuJPh...7..297K 10.1071/PH540297 Kerr, F.J., Hindman, J.V., and Robinson, B J., 1954. Observations of the 21 cm line from the Magellanic Clouds. Australian Journal of Physics, 7, 297-314. JV Kuilenburg 1972 A systematic search for high-velocity hydrogen outside the Galactic Plane II Astronomy and Astrophysics 16 276 1972A&A....16..276V Kuilenburg, J.V., 1972. A systematic search for high-velocity hydrogen outside the Galactic Plane II. Astronomy and Astrophysics, 16, 276. KK Kwee CA Muller G Westerhout 1954 The rotation of the inner parts of the galactic system Bulletin of the Astronomical Institutes of the Netherlands 12 211 222 1954BAN....12..211K Kwee, K.K., Muller, C.A., and Westerhout, G., 1954. The rotation of the inner parts of the galactic system. Bulletin of the Astronomical Institutes of the Netherlands, 12, 211-222. EM Lindsay 1958 The cluster system of the Small Magellanic Cloud Monthly Notices of the Royal Astronomical Society 118 172 182 1958MNRAS.118..172L Lindsay, E.M., 1958. The cluster system of the Small Magellanic Cloud. Monthly Notices of the Royal Astronomical Society, 118, 172-182. EM Lindsay 1961 A new catalogue of emission-line stars and planetary nebulae in the Sma DS Mathewson MN Cleary JD Murray 1974 The Magellanic Stream Astrophysical Journal 190 291 296 1974ApJ...190..291M 10.1086/152875 Mathewson, D.S., Cleary, M.N., and Murray, J.D., 1974. The Magellanic Stream. Astrophysical Journal, 190, 291-296. Mathewson, D.S., Healey, J.R., and Rome, J.M., 1962. A radio survey of the southern Milky Way at a frequency of 1440 Mc/s. II. The continuum emission from the Galactic disk. Australian Journal of Physics, 15, 369-377. DS Mathewson SR Wayte VL Ford K Ruan 1987 The `high velocity cloud' origin of the Magellanic system Proceedings of the Astronomical Society of Australia 7 19 25 1987PASAu...7...19M Mathewson, D.S., Wayte, S.R., Ford, V.L., and Ruan, K., 1987. The `high velocity cloud' origin of the Magellanic system. Proceedings of the Astronomical Society of Australia, 7, 19-25. NM McClure-Griffiths L Staveley-Smith FJ Lockman MR Calabretta HA Ford PMW Kalberla T Murphy H Nakanishi DJ Pisano 2008 An interaction of a Magellanic leading arm high-velocity cloud with the Milky Way disk Astrophysical Journal 673 L143 L146 2008ApJ...673L.143M 10.1086/528683 McClure-Griffiths, N.M., Staveley-Smith, L., Lockman, F.J., Calabretta, M.R., Ford, H.A., Kalberla, P.M. W., Murphy, T., Nakanishi, H., and Pisano, D.J., 2008. An interaction of a Magellanic leading arm high-velocity cloud with the Milky Way disk. Astrophysical Journal, 673, L143-L146. McCready, L.L., 1954. Letter to J.L. Pawsey, dated 19 August. National Archives of Australia, Sydney, 974347 - C3830 - F1/4/PAW/1. McCready, L.L., 1957. Letter to J.L. Pawsey, dated 28 October. National Archives of Australia, Sydney, 974347 - C3830 - F1/4/PAW/1. RX McGee 1964 Large HI clouds in the Galaxy FJ Kerr The Galaxy and the Magellanic Clouds. Proceedings of the International Astronomical Union Symposium No. 20 Held in Canberra March 18-28, 1963 Australian Academy of Science. Pp Canberra 126 130 McGee, R.X., 1964. Large HI clouds in the Galaxy. In Kerr, F.J. (ed.). The Galaxy and the Magellanic Clouds. Proceedings of the International Astronomical Union Symposium No. 20 Held in Canberra March 18-28, 1963. Canberra, Australian Academy of Science. Pp. 126-130. McGee, R.X., and Milton, J.A., 1964. A sky survey of neutral hydrogen at λ 21 cm. III. Gas at higher radial velocities. Australian Journal of Physics, 17, 128-157. RX McGee JD Murray 1961 McGee, R.X., and Murray, J.D., 1961b. A sky survey of neutral hydrogen at λ 21 cm I. The general distribution and motions of the local gas. Australian Journal of Physics, 14, 260-278. McGee, R.X., Murray, J.D., and Milton, J.A., 1963. A sky survey of neutral hydrogen at λ 21 cm. II. The detailed distribution of low velocity gas. Australian Journal of Physics, 16, 136-170. RX McGee JD Murray JL Pawsey 1961 Streaming of interstellar hydrogen in the vicinity of the Sun Nature 189 957 959 1961Natur.189..957M 10.1038/189957a0 McGee, R.X., Murray, J.D., and Pawsey, J.L., 1961. Streaming of interstellar hydrogen in the vicinity of the Sun. Nature, 189, 957-959. KM Menten MJ Reid J Forbrich A Brunthaler 2007 The distance to the Orion Nebula Astronomy and Astrophysics 474 515 520 2007A&A...474..515M 10.1051/0004-6361:20078247 Menten, K.M., Reid, M.J., Forbrich, J., and Brunthaler, A., 2007. The distance to the Orion Nebula. Astronomy and Astrophysics, 474, 515-520. CA Muller G Westerhout 1957 A catalogue of 21-cm line profiles Bulletin of the Astronomical Institutes of the Netherlands 13 151 195 1957BAN....13..151M Muller, C.A., and Westerhout, G., 1957. A catalogue of 21-cm line profiles. Bulletin of the Astronomical Institutes of the Netherlands, 13, 151-195. JD Murray RX McGee 1958 A new hydrogen cloud in Pyxis-Hydra The Observatory 78 242 244 1958Obs....78..242M Murray, J.D., and McGee, R.X., 1958. A new hydrogen cloud in Pyxis-Hydra. The Observatory, 78, 242-244. JD Murray RX McGee 1959 Neutral hydrogen gas in the Taurus-Orion region observed with a multichannel 21 cm line receiver Australian Journal of Physics 12 127 133 1959AuJPh..12..127M 10.1071/PH590127 Murray, J.D., and McGee, R.X., 1959. Neutral hydrogen gas in the Taurus-Orion region observed with a multichannel 21 cm line receiver. Australian Journal of Physics, 12, 127-133. JD Murray RX McGee 1963 A multi-channel hydrogen line (21 cm) receiver Proceedings of the Institute of Radio Engineers Australia 24 191 196 Murray, J.D., and McGee, R.X., 1963. A multi-channel hydrogen line (21 cm) receiver. Proceedings of the Institute of Radio Engineers Australia, 24, 191-196. A Ollongren HC Hulst van de 1957 Corrections of 21-cm line profiles Bulletin of the Astronomical Institutes of the Netherlands 13 196 200 1957BAN....13..196O Ollongren, A., and van de Hulst, H.C., 1957. Corrections of 21-cm line profiles. Bulletin of the Astronomical Institutes of the Netherlands, 13, 196-200. W Orchiston 1993 New Zealand's role in the identification of the first "radio stars" Southern Stars 35 46 52 1993SouSt..35...46O Orchiston, W., 1993. New Zealand's role in the identification of the first "radio stars." Southern Stars, 35, 46-52. W Orchiston 1994 John Bolton, discrete sources, and the New Zealand field-trip of 1948 Australian Journal of Physics 47 541 547 1994AuJPh..47..541O Orchiston, W., 1994. John Bolton, discrete sources, and the New Zealand field-trip of 1948. Australian Journal of Physics, 47, 541-547 Orchiston, W., 2004. The rise and fall of the Chris Cross: a pioneering Australian radio telescope. In Orchiston, W., Stephenson, R., Debarbat, S., and Nha, I.-S. (eds.). Astronomical Instruments and Archives from the Asia-Pacific Region. Seoul, IAU Commission 41. Pp. 157-162. W Orchiston D Mathewson 2009 Chris Christiansen and the Chris Cross Journal of Astronomical History and Heritage 12 11 32 2009JAHH...12...11O Orchiston, W., and Mathewson, D., 2009. Chris Christiansen and the Chris Cross. Journal of Astronomical History and Heritage, 12, 11-32. W Orchiston B Slee 2002 Ingenuity and initiative in Australian radio astronomy: the Dover Heights `hole-in-the-ground' antenna Journal of Astronomical History and Heritage 5 21 34 2002JAHH....5...21O Orchiston, W., and Slee, B., 2002. Ingenuity and initiative in Australian radio astronomy: the Dover Heights `hole-in-the-ground' antenna. Journal of Astronomical History and Heritage, 5, 21-34. W Orchiston B Slee 2005 The Radiophysics field stations and the early development of radio astronomy W Orchiston The New Astronomy: Opening the Electromagnetic Window and Expanding our View of Planet Earth Springer. Pp Dordrecht 119 168 10.1007/1-4020-3724-4_8 Orchiston, W., and Slee, B., 2005. The Radiophysics field stations and the early development of radio astronomy. In Orchiston, W. (ed.). The New Astronomy: Opening the Electromagnetic Window and Expanding our View of Planet Earth. Dordrecht, Springer. Pp. 119-168. W Orchiston T Nakamura R Strom 2011 Highlighting the History of Astronomy in the Asia-Pacific Region New York Springer Orchiston, W., Nakamura, T., and Strom, R. (eds.), 2011. Highlighting the History of Astronomy in the Asia-Pacific Region. New York, Springer. AEE Rodgers KA Dudevoir JC Carter BJ Fanous E Kratzenberg 2005 Deuterium abundance in the interstellar gas of the Galactic Anticentre from the 327 MHz Line Astrophysical Journal 630 L41 L44 2005ApJ...630L..41R 10.1086/466524 Rodgers, A.E.E., Dudevoir, K.A., Carter, J.C., Fanous, B.J., and Kratzenberg, E., 2005. Deuterium abundance in the interstellar gas of the Galactic Anticentre from the 327 MHz Line. Astrophysical Journal, 630, L41-L44. VC Rubin WK Ford 1970 Rotation of the Andromeda Nebula from a spectroscopic survey of emission regions Astrophysical Journal 159 379 403 1970ApJ...159..379R 10.1086/150317 Rubin, V.C., and Ford, W.K., 1970. Rotation of the Andromeda Nebula from a spectroscopic survey of emission regions. Astrophysical Journal, 159, 379-403. M Schmidt 1957 Spiral structure in the inner parts of the galactic system derived from the hydrogen emission at 21-cm wavelength Bulletin of the Astronomical Institutes of the Netherlands 13 247 268 1957BAN....13..247S Schmidt, M., 1957. Spiral structure in the inner parts of the galactic system derived from the hydrogen emission at 21-cm wavelength. Bulletin of the Astronomical Institutes of the Netherlands, 13, 247-268. GA Shain 1957 The inclination to the Galactic Equator of the general magnetic field of LS Sparke JS Gallagher 2000 Galaxies in the Universe: An Introduction Cambridge University Press Cambridge Sparke, L.S., and Gallagher, J.S., 2000. Galaxies in the Universe: An Introduction, Cambridge, Cambridge University Press. S Stanimirovic L Staveley-Smith JM Dickey RJ Sault SL Snowden 1999 The large-scale HI structure of the Small Magellanic Cloud Monthly Notices of the Royal Astronomical Society 302 417 436 1999MNRAS.302..417S 10.1046/j.1365-8711.1999.02013.x Stanimirovic, S., Staveley-Smith, L., Dickey, J.M., Sault, R.J., and Snowden, S.L., 1999. The large-scale HI structure of the Small Magellanic Cloud. Monthly Notices of the Royal Astronomical Society, 302, 417-436. GJ Stanley R Price 1956 An investigation of monochromatic radio emission of deuterium from the Galaxy Nature 177 1221 1222 1956Natur.177.1221S 10.1038/1771221a0 Stanley, G.J., and Price, R., 1956. An investigation of monochromatic radio emission of deuterium from the Galaxy. Nature, 177, 1221-1222. Stanley, G.J., 1994. Recollections of John G. Bolton at Dover Heights and Caltech. Australian Journal of Physics, 47, 507-516. WT Sullivan 2009 Cosmic Noise. A History of Early Radio Astronomy Cambridge University Press Cambridge Sullivan, W.T., 2009. Cosmic Noise. A History of Early Radio Astronomy. Cambridge, Cambridge University Press. Townes, C.H., 1957. Microwave and radio-frequency resonance lines of interest to radio astronomy. In van de Hulst, 92-103. HC Hulst van de 1957 Radio Astronomy, Proceedings from 4th IAU Symposium. International Astronomical Union Cambridge Cambridge University Press van de Hulst, H.C. (ed.), 1957. Radio Astronomy, Proceedings from 4th IAU Symposium. International Astronomical Union. Cambridge, Cambridge University Press. HC Hulst van de 1958 Density and velocity distribution of the interstellar gas Reviews of Modern Physics 30 913 923 1958RvMP...30..913V 10.1103/RevModPhys.30.913 van de Hulst, H.C., 1958. Density and velocity distribution of the interstellar gas. Reviews of Modern Physics, 30, 913-923. HC Hulst van de CA Muller JH Oort 1954 The spiral structure of the outer part of the galactic system derived from the hydrogen emission at 21 cm wavelength Bulletin of the Astronomical Institutes of the Netherlands 12 117 149 1954BAN....12..117V van de Hulst, H.C., Muller, C.A., and Oort, J.H., 1954. The spiral structure of the outer part of the galactic system derived from the hydrogen emission at 21 cm wavelength. Bulletin of the Astronomical Institutes of the Netherlands, 12, 117-149. H Woerden van R Strom 2006 The beginnings of radio astronomy in the Netherlands Journal of Astronomical History and Heritage 9 3 20 2006JAHH....9....3V van Woerden, H., and Strom, R., 2006. The beginnings of radio astronomy in the Netherlands. Journal of Astronomical History and Heritage, 9, 3-20. P Wannier GT Wrixon 1972 An unusual high-velocity hydrogen feature Astrophysical Journal 173 119 123 1972ApJ...173L.119W 10.1086/180930 Wannier, P., and Wrixon, G.T., 1972. 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The radio-frequency line spectrum of atomic hydrogen and its applications in astronomy. Astrophysical Journal, 115, 206-221. -
Initial alignment method for free space optics laser beam
NASA Astrophysics Data System (ADS)
Shimada, Yuta; Tashiro, Yuki; Izumi, Kiyotaka; Yoshida, Koichi; Tsujimura, Takeshi
2016-08-01
The authors have newly proposed and constructed an active free space optics transmission system. It is equipped with a motor driven laser emitting mechanism and positioning photodiodes, and it transmits a collimated thin laser beam and accurately steers the laser beam direction. It is necessary to introduce the laser beam within sensible range of the receiver in advance of laser beam tracking control. This paper studies an estimation method of laser reaching point for initial laser beam alignment. Distributed photodiodes detect laser luminescence at respective position, and the optical axis of laser beam is analytically presumed based on the Gaussian beam optics. Computer simulation evaluates the accuracy of the proposed estimation methods, and results disclose that the methods help us to guide the laser beam to a distant receiver.
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On-demand virtual optical network access using 100 Gb/s Ethernet.
Ishida, Osamu; Takamichi, Toru; Arai, Sachine; Kawate, Ryusuke; Toyoda, Hidehiro; Morita, Itsuro; Araki, Soichiro; Ichikawa, Toshiyuki; Hoshida, Takeshi; Murai, Hitoshi
2011-12-12
Our Terabit LAN initiatives attempt to enhance the scalability and utilization of lambda resources. This paper describes bandwidth-on-demand virtualized 100GE access to WDM networks on a field fiber test-bed using multi-domain optical-path provisioning. © 2011 Optical Society of America
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National Unmanned Aircraft Systems Project Office
Goplen, Susan E.; Sloan, Jeff L.
2015-01-01
The U.S. Geological Survey (USGS) National Unmanned Aircraft Systems (UAS) Project Office leads the implementation of UAS technology in the Department of the Interior (DOI). Our mission is to support the transition of UAS into DOI as a new cost-effective tool for collecting remote-sensing data to monitor environmental conditions, respond to natural hazards, recognize the consequences and benefits of land and climate change and conduct wildlife inventories. The USGS is teaming with all DOI agencies and academia as well as local, State, and Tribal governments with guidance from the Federal Aviation Administration and the DOI Office of Aviation Services (OAS) to lead the safe, efficient, costeffective and leading-edge adoption of UAS technology into the scientific research and operational activities of the DOI.
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NASA Astrophysics Data System (ADS)
Manaud, Nicolas; Rossi, Angelo Pio; Hare, Trent; Aye, Michael; Galluzzi, Valentina; van Gasselt, Stephan; Martinez, Santa; McAuliffe, Jonathan; Million, Chase; Nass, Andrea; Zinzi, Angelo
2016-10-01
"Open" has become attached to several concepts: science, data, and software are some of the most obvious. It is already common practice within the planetary science community to share spacecraft missions data freely and openly [1]. However, this is not historically the case for software tools, source code, and derived data sets, which are often reproduced independently by multiple individuals and groups. Sharing data, tools and overall knowledge would increase scientific return and benefits [e.g. 2], and recent projects and initiatives are helping toward this goal [e.g. 3,4,5,6].OpenPlanetary is a bottom-up initiative to address the need of the planetary science community for sharing ideas and collaborating on common planetary research and data analysis problems, new challenges, and opportunities. It started from an initial participants effort to stay connected and share information related to and beyond the ESA's first Planetary GIS Workshop [7]. It then continued during the 2nd (US) Planetary Data Workshop [8], and aggregated more people.Our objective is to build an online distributed framework enabling open collaborations within the planetary science community. We aim to co-create, curate and publish resource materials and data sets; to organise online events, to support community-based projects development; and to offer a real-time communication channel at and between conferences and workshops.We will present our current framework and resources, developing projects and ideas, and solicit for feedback and participation. OpenPlanetary is intended for research and education professionals: scientists, engineers, designers, teachers and students, as well as the general public that includes enthusiasts and citizen scientists. All are welcome to join and contribute at openplanetary.co[1] International Planetary Data Alliance, planetarydata.org. [2] Nosek et al (2015), dx.doi.org/10.1126/science.aab2374. [3] Erard S. et al. (2016), EGU2016-17527. [4] Proposal for a PDS Software Node, bit.ly/PDS_SN. [5] Zinzi et al. (2016), dx.doi.org/10.1016/j.ascom.2016.02.006. [6] Open Universe initiave, bit.ly/OpenUniverse, [7] Manaud N. et al. (2016), LPSC47-1387. [8] bit.ly/PlanetaryDataWorkshops
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Consent Agreement with the DOI, BIA and Bureau of Indian Education (BIE) on alleged violations at schools and public water systems owned, operated or the responsibility of DOI. Violations occurred under the CAA, CWA, SDWA, TSCA, ADHERA.
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43 CFR 17.323 - Information collection requirements.
Code of Federal Regulations, 2010 CFR
2010-10-01
... of Doi Recipients § 17.323 Information collection requirements. Each recipient shall: (a) Keep records in a form and containing information which DOI determines may be necessary to ascertain whether the recipient is complying with the Act and these regulations. (b) Provide to DOI, upon request...
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43 CFR 17.337 - Remedial action by recipients.
Code of Federal Regulations, 2010 CFR
2010-10-01
... Investigation, Conciliation, and Enforcement Procedures § 17.337 Remedial action by recipients. Where DOI finds... DOI may require to overcome the effects of the discrimination. If another recipient exercises control over the recipient that has discriminated, DOI may require both recipients to take remedial action. ...
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30 CFR 229.109 - Reimbursement for costs incurred by a State under the delegation of authority.
Code of Federal Regulations, 2010 CFR
2010-07-01
... authority. (a) The Department of the Interior (DOI) shall reimburse the State for 100 percent of the direct... maintain books and records in accordance with the standards established by the DOI and will provide the DOI...
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30 CFR 1229.109 - Reimbursement for costs incurred by a State under the delegation of authority.
Code of Federal Regulations, 2011 CFR
2011-07-01
... under the delegation of authority. (a) The Department of the Interior (DOI) shall reimburse the State... DOI and will provide the DOI, on a quarterly basis, a summary of costs incurred for which the State is...
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43 CFR 17.323 - Information collection requirements.
Code of Federal Regulations, 2011 CFR
2011-10-01
... of Doi Recipients § 17.323 Information collection requirements. Each recipient shall: (a) Keep records in a form and containing information which DOI determines may be necessary to ascertain whether the recipient is complying with the Act and these regulations. (b) Provide to DOI, upon request...
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43 CFR 17.337 - Remedial action by recipients.
Code of Federal Regulations, 2011 CFR
2011-10-01
... Investigation, Conciliation, and Enforcement Procedures § 17.337 Remedial action by recipients. Where DOI finds... DOI may require to overcome the effects of the discrimination. If another recipient exercises control over the recipient that has discriminated, DOI may require both recipients to take remedial action. ...
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NASA Astrophysics Data System (ADS)
Melle, W.; Runge, J. A.; Head, E.; Plourde, S.; Castellani, C.; Licandro, P.; Pierson, J.; Jonasdottir, S. H.; Johnson, C.; Broms, C.; Debes, H.; Falkenhaug, T.; Gaard, E.; Gislason, A.; Heath, M. R.; Niehoff, B.; Nielsen, T. G.; Pepin, P.; Stenevik, E. K.; Chust, G.
2014-04-01
Here we present a new, pan-Atlantic compilation of data on key mesozooplankton species, including the possibly most important copepod, Calanus finmarchicus. Distributional data of ten representative zooplankton taxa, from recent (2000-2009) Continuous Plankton Recorder data, are presented, along with basin-scale data of the phytoplankton colour index. Then we present a compilation of data on C. finmarchicus including observations of abundance, demography, egg production and female size with accompanying data on temperature and chlorophyll. This is a contribution by Canadian, European and US scientists and their institutions. http://doi.pangaea.de/10.1594/PANGAEA.820732, http://doi.pangaea.de/10.1594/PANGAEA.824423, http://doi.pangaea.de/10.1594/PANGAEA.828393.
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Initial Test Bed for Very High Efficiency Solar Cells
2008-05-01
efficiency, both at the solar cell and module levels. The optical system consists of a tiled nonimaging concentrating system, coupled with a spectral...Benítez, P. (2005). Nonimaging Optics . Boston: Elsevier Academic Press. [6] Luque, A.L. & Andreev, V.M. (2007). Concentrator Photovoltaics. New York: Springer. ...lateral optical concentrating system, which splits the incident solar spectrum into several bands and allows different optical and photovoltaic
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Optical Techniques for the Remote Detection of Biological Aerosols
1974-08-01
1) Laboratory exneriments (2) Remote detection experiments. In the first phase , the optical characteristics of several selected biological...the-art optical sensor system. The estimates were favorable, and a second research phase was initiated. Remote detection experiments were conducted...that of phase fluorometry. The fluorescence is excited by 3. continuous light source, the output of which is modulated at a high freeuency by an optical
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Svrakic, Maja; Roland, J. Thomas; McMenomey, Sean O.; Svirsky, Mario A.
2016-01-01
OBJECTIVE To describe our initial operative experience and hearing preservation results with the Advanced Bionics (AB) Mid Scala Electrode (MSE) STUDY DESIGN Retrospective review. SETTING Tertiary referral center. PATIENTS Sixty-three MSE implants in pediatric and adult patients were compared to age- and gender-matched 1j electrode implants from the same manufacturer. All patients were severe to profoundly deaf. INTERVENTION Cochlear implantation with either the AB 1j electrode or the AB MSE. MAIN OUTCOME MEASURES The MSE and 1j electrode were compared in their angular depth of insertion (aDOI) and pre- to post-operative change in hearing thresholds. Hearing preservation was analyzed as a function of aDOI. Secondary outcome measures included operative time, incidence of abnormal intraoperative impedance and telemetry values, and incidence of postsurgical complications. RESULTS Depth of insertion was similar for both electrodes, but was more consistent for the MSE array and more variable for the 1j array. Patients with MSE electrodes had better hearing preservation. Thresholds shifts at four audiometric frequencies ranging from 250 to 2,000 Hz were 10 dB, 7 dB, 2 dB and 6 dB smaller for the MSE electrode than for the 1j (p<0.05). Hearing preservation at low frequencies was worse with deeper insertion, regardless of array. Secondary outcome measures were similar for both electrodes. CONCLUSIONS The MSE electrode resulted in more consistent insertion depth and somewhat better hearing preservation than the 1j electrode. Differences in other surgical outcome measures were small or unlikely to have a meaningful effect. PMID:27755356
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NASA Astrophysics Data System (ADS)
Sandvik, Oscar S.; Martinsson, Bengt G.; Friberg, Johan; Hermann, Markus; van Velthoven, Peter J. F.; Zahn, Andreas
2017-04-01
In this study two aerosol measurement platforms have been compared. Aerosol optical depth (AOD) per meter in the lowermost stratosphere was obtained with the "In-service Aircraft for a Global Observing System - Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container" (IAGOS-CARIBIC) platform and with the "Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation" (CALIPSO) satellite. The in situ measurements were taken from the IAGOS-CARIBIC platform, where sampling of aerosol and trace gases was undertaken in the altitude range 9 - 12 km from a passenger aircraft, usually on four intercontinental flights a month (Brenninkmeijer et al., 2007). Here we use impactor samples that were analyzed for elemental concentrations with Particle-Induced X-ray Emission (PIXE) and Particle Elastic Scattering Analysis (PESA) (Nguyen et al., 2006; Martinsson et al., 2014). The comparison was based on the sulfurous aerosol, which is the main component of the aerosol in the stratosphere. From the amount of sulfur, the AOD per meter could be estimated, assuming standard stratospheric aerosol composition (75% sulfuric acid and 25% water) and stratospheric background particle size distribution (Jäger and Deshler, 2002). The CALIPSO measurements were taken with a polarization-sensitive lidar with a high vertical resolution, of 30 m at most, using laser wavelengths of 532 nm and 1064 nm. In this study level 1b data was used to calculate AOD per meter. Clouds were removed based on depolarization ratio (Vernier et al., 2009). The results from the two measurement platforms were compared with each other for time periods after the volcanic eruptions of Sarychev (2009) and Nabro (2011) as well as the period from autumn 2013 to early spring of 2014 which had small volcanic influence. The measurements in this study were taken between 40°N and 75°N. Vertical profiles of AOD per meter were created for data above the tropopause. In this study the dynamical tropopause at 1.5 PVU was used (Gettelman et al. 2011). The increase of the AOD per meter with height above the tropopause reflected that the concentration of volcanic aerosols was denser at higher altitudes. After volcanic eruptions the agreement between the two measurement platforms is good except during spring, where substantial differences between the two measurement platforms were observed. These differences could have been caused by a presence of soil dust above the tropopause. For the period of small volcanic influence CALIPSO systematically reported higher AOD per meter values than IAGOS-CARIBIC, thus indicating that aerosol components other than particulate sulfur were contributing to the CALIPSO measurements. Brenninkmeijer C.A.M. et al. (2007). Atmos. Chem. Phys., 7, 4953-4976, doi:10.5194/acp-7-4953-2007 Nguyen H.N. et al. (2006). Aerosol Sci. Technol., 40, 649-655, doi:10.1080/02786820600767807 Martinsson et al. (2014). Atmos. Meas. Tech., 7, 2581-2596, doi:10.5194/amt-7-2581-2014 Jäger and Deshler (2002). Geophys. Res. Lett., 29, 1929, doi:10.1029/2002GL015609 Vernier et al. (2009). J. Geophys. Res., 114, D00H10, doi:10.1029/2009JD011946 Gettelman et al. (2011). Rev. Geophys., 49, RG3003, doi:10.1029/2011RG000355
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A multiplexed TOF and DOI capable PET detector using a binary position sensitive network.
Bieniosek, M F; Cates, J W; Levin, C S
2016-11-07
Time of flight (TOF) and depth of interaction (DOI) capabilities can significantly enhance the quality and uniformity of positron emission tomography (PET) images. Many proposed TOF/DOI PET detectors require complex readout systems using additional photosensors, active cooling, or waveform sampling. This work describes a high performance, low complexity, room temperature TOF/DOI PET module. The module uses multiplexed timing channels to significantly reduce the electronic readout complexity of the PET detector while maintaining excellent timing, energy, and position resolution. DOI was determined using a two layer light sharing scintillation crystal array with a novel binary position sensitive network. A 20 mm effective thickness LYSO crystal array with four 3 mm × 3 mm silicon photomultipliers (SiPM) read out by a single timing channel, one energy channel and two position channels achieved a full width half maximum (FWHM) coincidence time resolution of 180 ± 2 ps with 10 mm of DOI resolution and 11% energy resolution. With sixteen 3 mm × 3 mm SiPMs read out by a single timing channel, one energy channel and four position channels a coincidence time resolution 204 ± 1 ps was achieved with 10 mm of DOI resolution and 15% energy resolution. The methods presented here could significantly simplify the construction of high performance TOF/DOI PET detectors.
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Thermodynamic output of single-atom quantum optical amplifiers and their phase-space fingerprint
NASA Astrophysics Data System (ADS)
Perl, Y.; Band, Y. B.; Boukobza, E.
2017-05-01
We analyze a resonant single-atom two-photon quantum optical amplifier both dynamically and thermodynamically. A detailed thermodynamic analysis shows that the nonlinear amplifier is thermodynamically equivalent to the linear amplifier. However, by calculating the Wigner quasiprobability distribution for various initial field states, we show that unique quantum features in optical phase space, absent in the linear amplifier, are retained for extended times, despite the fact that dissipation tends to wash out dynamical features observed at early evolution times. These features are related to the discrete nature of the two-photon matter-field interaction and fingerprint the initial field state at thermodynamic times.
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Water vapor in the Martian atmosphere by SPICAM IR/Mars-Express
NASA Astrophysics Data System (ADS)
Trokhimovskiy, Alexander; Fedorova, Anna; Korablev, Oleg; Bertaux, Jean-Loup; Villard, Eric; Rodin, Alexander V.
Introduction SPICAM experiment along with PFS and OMEGA spectrometers on Mars Express has a capability to sound the water vapor in the atmosphere. The results of H2O measurements have been intensively published during last years [1-6]. Here we present the new analysis of SPICAM IR water vapor measurements, covering two Martian years. The near-IR channel of SPICAM experiment on Mars Express spacecraft is a 800-g acousto-optic tunable filter (AOTF)-based spectrometer operating in the spectral range of 1-1.7 m with resolving power of 2000 [7, 8]. The nadir measurements of H2O in the 1.37-m spectral band is one of the main objectives of the experiment. Data treatment As compared with previous analysis of water vapor presented in [4] we used the spectroscopic database HITRAN2004 [9] instead of HITRAN 2000 and the most recent measurements of the water line-width broadening in CO2 atmosphere. Latest version HITRAN2008 doesn't have any meaningful changes in water vapour lines, which are used for retrievment. Martian Climate Database V4.2 [10] was adopted for modelling of synthetic spectra and a scenario based on TES MY24 was used. The spare model of SPICAM IR instrument was recalibrated in June 2007 in Reims, to analyze specifically the sensitivity to the H2O vapor band. According to laboratory measurements, a leakage from the AOTF is responsible up to 5 Radiative transfer modelling and results Sensitivity of retrieval to aerosol scattering and different vertical distributions of aerosol and water vapor was analyzed for H2O absorption band at 1.38 m and 2.56 m for different dust particles. Dependences of equivalent width of the H2O band on the water vapor abundance and aerosol optical depth for different vertical distribution of water vapor and aerosol optical depth are obtained. A number of orbits processed with "honest" aerosol account, in some cases difference to clear atmosphere approach is meaningful. Open questions for further processing are great demand in computer resources and uncertainty about Martian atmosphere octal depths. Right now we are using data from SPICAM UV channel and PFS instrument onboard Mars Express. Calculations of Martian atmospheric dust optical for different particle models properties are done as well to shift data from one wavelength to another For today SPICAM data from January 2004 to January 2010, i.e. three Martian years, is fully processed in aspect of water vapor retrievment in the assumption of clear atmosphere. The seasonal trend of water vapor obtained by SPICAM IR is consistent with TES results and disagrees with MAWD South pole maximum measurements. The maximum abundance is 50-55 pr. m at the North pole (during MY28 data are missing) and 13-16 pr.m at the South pole. The northern tropical maximum amounts to 11-14 pr m. The seasonal trend of water vapor obtained by SPICAM IR is consistent for MY27 with TES results [11]. The South Pole maximum for MY28 agrees well with the MAWD South Pole measurements in 1977 [12]. It assumes the same dust conditions and global dust storm happened at MY28 Ls 270 like during the MAWD observations. The maximum near 30-60S at Ls 260 relates to Hellas observations. Recent observations of water vapour distribution during the same period by CRISM spectrometer onboard Mars Reconnaissance Orbiter support these results [6] References [1] Fouchet, T., (2007), Icarus 190, 32-49. [2] Melchiorri, R. (2007), PSS 55, 333-342. [3] Encrenaz, Th. (2005), AA 441, L9-L12. [4] Fedorova, A. et al. (2006), JGR 111, DOI:10.1029/2006JE002695. [5] R. Melchiorri. et al. (2009), Icarus, Volume 201, Issue 1, May 2009, Pages 102-112. [6] Smith, M. et al. (2009), JGR 114, , DOI:10.1029/2008JE003288, 2009 [7] Bertaux, J.-L. et al. (2006), JGR 111, DOI:10.1029/2006JE002690. [8] Korablev, O. et al. (2006), JGR 111, DOI:10.1029/2006JE002696. [9] Rothman, L.S. et al. (2005), JQSRT, 96, 139-204. [10] Forget, F. et al. (2007), LPICo1353.3098F. [11] Smith, M., (2004), Icarus 167, 148-165. [12] Jakosky, B. M., and C. B. Farmer, (1982), J. Geophys. Res., 87, B4, 2999-3019
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30 CFR 250.1005 - Inspection requirements for DOI pipelines.
Code of Federal Regulations, 2010 CFR
2010-07-01
... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Inspection requirements for DOI pipelines. 250.1005 Section 250.1005 Mineral Resources MINERALS MANAGEMENT SERVICE, DEPARTMENT OF THE INTERIOR...-Way § 250.1005 Inspection requirements for DOI pipelines. (a) Pipeline routes shall be inspected at...
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43 CFR 17.330 - Compliance reviews.
Code of Federal Regulations, 2011 CFR
2011-10-01
..., Conciliation, and Enforcement Procedures § 17.330 Compliance reviews. (a) DOI may conduct compliance reviews... and correct violations of the Act and these regulations. DOI may conduct these reviews even in the... review indicates a violation of the Act or these regulations, DOI will attempt to secure voluntary...
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NASA Astrophysics Data System (ADS)
Taylor, C.; Birch, C.; Parker, D.; Guichard, F.; Nikulin, G.; Dixon, N.
2013-12-01
Land surface properties influence the life cycle of convective systems across West Africa via space-time variability in sensible and latent heat fluxes. Previous observational and modelling studies have shown that areas with strong mesoscale variability in vegetation cover or soil moisture induce coherent structures in the daytime planetary boundary layer. In particular, horizontal gradients in sensible heat flux can induce convergence zones which favour the initiation of deep convection. A recent study based on satellite data (Taylor et al. 2011), illustrated the climatological importance of soil moisture gradients in the initiation of long-lived Mesoscale Convective Systems (MCS) in the Sahel. Here we provide a unique assessment of how models of different spatial resolutions represent soil moisture - precipitation feedbacks in the region, and compare their behaviour to observations. Specifically we examine whether the inability of large-scale models to capture the observed preference for afternoon rain over drier soil in semi-arid regions [Taylor et al., 2012] is due to inadequate spatial resolution and/or systematic bias in convective parameterisations. Firstly, we use a convection-permitting simulation at 4km resolution to explore the underlying mechanisms responsible for soil moisture controls on daytime convective initiation in the Sahel. The model reproduces very similar spatial structure as the observations in terms of antecedent soil moisture in the vicinity of a large sample of convective initiations. We then examine how this same model, run at coarser resolution, simulates the feedback of soil moisture on daily rainfall. In particular we examine the impact of switching on the convective parameterisation on rainfall persistence, and compare the findings with 10 regional climate models (RCMs). Finally, we quantify the impact of the feedback on dry-spell return times using a simple statistical model. The results highlight important weaknesses in convective parameterisations which are likely to impact land surface sensitivity studies and hydroclimatic variability on certain time and space scales. Taylor, C.M., Gounou, A., Guichard, F., Harris, P.P., Ellis, R.J.,Couvreux, F., and M. De Kauwe. 2011, Frequency of Sahelian storm initiation enhanced over mesoscale soil-moisture patterns, Nature Geoscience, 4, 430-433, doi:10.1038/ngeo1173 Taylor, C.M., de Jeu, R.A.M., Guichard, F., Harris, P.P, and W.A. Dorigo. 2012, Afternoon rain more likely over drier soils, Nature, 489, 423-426, doi:10.1038/nature11377
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"Where did my data layer come from?" The semantics of data release
NASA Astrophysics Data System (ADS)
Leadbetter, Adam; Buck, Justin
2015-04-01
In his lecture, "Theory of Creative Fitting" (Margullis, Corner & Holt, 2006), Ian McHarg introduced his vision for cross-disciplinary data and information sharing networks with the end goal of producing detailed overlay maps for the purposes of ecological architectural planning. Within McHarg's networks, experts in various fields, such as hydrology or surface geology, would provide data layers to the final overlay map with full provenance, such that the users of the overlay maps would know the originator of the data, the "value systems" by which the data were created and could place their trust in the outcomes. In the light of McHarg's statements and in order to allow the encoding of value systems in a cyber-GIS, analyses of: data quality (Giarlo, 2013); data publication networks (Reinsfelder, 2012); trust in collaborative research networks (Leadbetter, 2015); and the metaphors of data publication, data release and data ecosystems (Parsons & Fox, 2013) have been synthesised into a logical model of the data release lifecycle. This model concerns the actors in the data release process; the data-information-knowledge ecosystem through the various stages of the data release process and the impact of data release on perceptions of trust through the data release lifecycle. The data-information-knowledge ecosystem described how the collection of data can be presented in new ways to form information products, and how these information products can inform conversations amongst information-consumers who integrate the information into new knowledge. The actors concerned in the process comprise: researchers data publishers academic publishers & academic administrators Finally, the lifecycle of data release involves the initial release of a data-layer, possibly with a Persistent Identifier (PID) more generic than a Digital Object Identifier (DOI). A data description paper can be written about the dataset, which then necessitates the assignment of a DOI to the datasets; the DOI can be seen as an indicator of trust through "benevolence". A technical document citing the dataset may then be informed by the dataset release or the dataset description paper. These citations may show the "competence" (in terms of a trust model) of the original datasets, and the dataset description papers or other technical articles show the integrity of the dataset. The synthesised logical model has been represented in freely available ontologies, such that data layers can be annotated with metadata about their provenance and stage within the data release lifecycle before incorporation into a cyber-GIS, in which distributed data providers provide for a collaborative research environment. References Giarlo, M. (2013). Academic libraries as data quality hubs. Journal of Librarianship and Scholarly Communication 1(3): eP1059. doi: 10.7710/2162-3309.1059 Leadbetter, A. (2015). Examining trust in collaborative research networks. In P. Diviacco, P. Fox, C. Pshenichny, and A. Leadbetter (Eds.) Collaborative Knowledge in Scientific Research Networks, Hershey, PA: IGI Global. doi: 10.4018/978-1-4666-6567-5.ch002 Margulis, L., Corner, J. and Hawthorne, B. (Editors), 2006. Ian McHarg: conversations with students. Dwelling with nature. New York, NY: Princeton Architectural Press. Parsons, M., and Fox, P. (2013). Is data publication the right metaphor? Data Science Journal 12, 32-46. doi:10.2481/dsj.WDS-042 Reinsfelder, T. (2012). Open access publishing practices in a complex environment: conditions, barriers and bases of power. Journal of Librarianship and Scholarly Communication 1(1): eP1029. doi: 10.7710/2162-3309.1029
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NASA Astrophysics Data System (ADS)
Potlov, A. Yu.; Frolov, S. V.; Proskurin, S. G.
2018-04-01
Optical structure disturbances localization algorithm for time-resolved diffuse optical tomography of biological objects is described. The key features of the presented algorithm are: the initial approximation for the spatial distribution of the optical characteristics based on the Homogeneity Index and the assumption that all the absorbing and scattering inhomogeneities in an investigated object are spherical and have the same absorption and scattering coefficients. The described algorithm can be used in the brain structures diagnosis, in traumatology and optical mammography.
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: Institute of Electrical and Electronics Engineers (IEEE). NREL/CP-5500-54165. doi:10.1109/EnergyTech 2011. Piscataway, NJ: Institute of Electrical and Electronics Engineers (IEEE). NREL/CP-5500-53565. doi Electrical and Electronics Engineers (IEEE). NREL/CP-550-47061. doi:10.1109/pes.2009.5275358 Mooney, D., M
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43 CFR 17.335 - Compliance procedure.
Code of Federal Regulations, 2010 CFR
2010-10-01
..., Conciliation, and Enforcement Procedures § 17.335 Compliance procedure. (a) DOI may enforce the Act and these regulations through: (1) Termination of a recipient's Federal financial assistance from DOI under the program... correcting a violation of the Act or these regulations. (b) DOI will limit any termination under § 17.335(a...
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Code of Federal Regulations, 2010 CFR
2010-07-01
... disposal agency receives the assignment recommendation from DOI? 102-75.665 Section 102-75.665 Public Contracts and Property Management Federal Property Management Regulations System (Continued) FEDERAL... assignment recommendation from DOI? If, after considering other uses for the property, the disposal agency...
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Federal Register 2010, 2011, 2012, 2013, 2014
2011-12-12
... Number 1040-0001, DOI Programmatic Clearance for Customer Satisfaction Surveys AGENCY: Department of [email protected] . Reference ``DOI Programmatic Clearance for Customer Satisfaction Surveys'' in your email... public accountability by promoting a new focus on results, service quality, and customer satisfaction...
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43 CFR 17.335 - Compliance procedure.
Code of Federal Regulations, 2011 CFR
2011-10-01
..., Conciliation, and Enforcement Procedures § 17.335 Compliance procedure. (a) DOI may enforce the Act and these regulations through: (1) Termination of a recipient's Federal financial assistance from DOI under the program... correcting a violation of the Act or these regulations. (b) DOI will limit any termination under § 17.335(a...
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30 CFR 250.1001 - Definitions.
Code of Federal Regulations, 2011 CFR
2011-07-01
...-Way § 250.1001 Definitions. Terms used in this subpart shall have the meanings given below: DOI... connecting production facilities on the OCS; (4) Transporter-operated pipelines that DOI and DOT have agreed are to be regulated as DOI pipelines; and (5) All OCS pipelines not subject to regulation under 49 CFR...
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30 CFR 250.1005 - Inspection requirements for DOI pipelines.
Code of Federal Regulations, 2011 CFR
2011-07-01
... 30 Mineral Resources 2 2011-07-01 2011-07-01 false Inspection requirements for DOI pipelines. 250.1005 Section 250.1005 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, REGULATION, AND ENFORCEMENT... Pipelines and Pipeline Rights-of-Way § 250.1005 Inspection requirements for DOI pipelines. (a) Pipeline...
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DOI Use of AVIRIS Data in Natural Resources Management: A Technology Transfer Project Status Report
NASA Technical Reports Server (NTRS)
Getter, James R.; Wickland, Diane
1998-01-01
A meeting was held in December 1996, attended by representatives from Department of the Interior (DOI) and National Aeronautical and Space Administration (NASA) at the request of Department of the Interior Secretary, Bruce Babbitt and NASA, Administrator Director Dan Goldin, to discuss the use of hyperspectral systems and related remote sensing technologies in addressing environmental issues of environmental importance to the (DOI). It was determined that NASA/DOI Coordination be established, comprised of representatives from each agency, designated to address the environmental issues and resulting technologies. A steering committee was formed consisting of representatives from NASA Headquarters, NASA PI's from University California-Davis, University of Colorado-Boulder, University of New Hampshire and DOI Bureaus (Indian Affairs, Land Management, Reclamation, National Park Service, and US Geological Survey).
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Liang, Yicheng; Peng, Hao
2015-02-07
Depth-of-interaction (DOI) poses a major challenge for a PET system to achieve uniform spatial resolution across the field-of-view, particularly for small animal and organ-dedicated PET systems. In this work, we implemented an analytical method to model system matrix for resolution recovery, which was then incorporated in PET image reconstruction on a graphical processing unit platform, due to its parallel processing capacity. The method utilizes the concepts of virtual DOI layers and multi-ray tracing to calculate the coincidence detection response function for a given line-of-response. The accuracy of the proposed method was validated for a small-bore PET insert to be used for simultaneous PET/MR breast imaging. In addition, the performance comparisons were studied among the following three cases: 1) no physical DOI and no resolution modeling; 2) two physical DOI layers and no resolution modeling; and 3) no physical DOI design but with a different number of virtual DOI layers. The image quality was quantitatively evaluated in terms of spatial resolution (full-width-half-maximum and position offset), contrast recovery coefficient and noise. The results indicate that the proposed method has the potential to be used as an alternative to other physical DOI designs and achieve comparable imaging performances, while reducing detector/system design cost and complexity.
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Mechanisms of Pulsed Laser Induced Damage to Optical Coatings
1986-07-01
photoionization of absorption centers . . . . . . . . . . . . . . . . . . . . 82 5 Electron densities achieved at 12.xiO" cm from color center initiation due...lends validity to this =~ del . It also provides an order of magnitide estimate of thýe range of the otherwise unknor optical absorption coefficient and...very high temperaturas can be reacheS in the center of the film while the boundaries remain nearly at their initial temperataure. In this case a
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2015-07-06
preparation for deterministic spin-photon entanglement ; (3) Demonstration of initialization of the 2 qubit states; (4) Demonstration of nonlocal nuclear...Demonstration of a flying qubit by entanglement of the quantum dot spin polarization with the polarization of a spontaneously emitted photon. Future...coherent optical control steps in preparation for deterministic spin-photon entanglement ; (3) Demonstration of initialization of the 2 qubit states in
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Four channel Laser Firing Unit using laser diodes
NASA Technical Reports Server (NTRS)
Rosner, David, Sr.; Spomer, Edwin, Sr.
1994-01-01
This paper describes the accomplishments and status of PS/EDD's (Pacific Scientific/Energy Dynamics Division) internal research and development effort to prototype and demonstrate a practical four channel laser firing unit (LFU) that uses laser diodes to initiate pyrotechnic events. The LFU individually initiates four ordnance devices using the energy from four diode lasers carried over the fiber optics. The LFU demonstrates end-to-end optical built in test (BIT) capabilities. Both Single Fiber Reflective BIT and Dual Fiber Reflective BIT approaches are discussed and reflection loss data is presented. This paper includes detailed discussions of the advantages and disadvantages of both BIT approaches, all-fire and no-fire levels, and BIT detection levels. The following topics are also addressed: electronic control and BIT circuits, fiber optic sizing and distribution, and an electromechanical shutter type safe/arm device. This paper shows the viability of laser diode initiation systems and single fiber BIT for typing military applications.
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Experimental test of an online ion-optics optimizer
NASA Astrophysics Data System (ADS)
Amthor, A. M.; Schillaci, Z. M.; Morrissey, D. J.; Portillo, M.; Schwarz, S.; Steiner, M.; Sumithrarachchi, Ch.
2018-07-01
A technique has been developed and tested to automatically adjust multiple electrostatic or magnetic multipoles on an ion optical beam line - according to a defined optimization algorithm - until an optimal tune is found. This approach simplifies the process of determining high-performance optical tunes, satisfying a given set of optical properties, for an ion optical system. The optimization approach is based on the particle swarm method and is entirely model independent, thus the success of the optimization does not depend on the accuracy of an extant ion optical model of the system to be optimized. Initial test runs of a first order optimization of a low-energy (<60 keV) all-electrostatic beamline at the NSCL show reliable convergence of nine quadrupole degrees of freedom to well-performing tunes within a reasonable number of trial solutions, roughly 500, with full beam optimization run times of roughly two hours. Improved tunes were found both for quasi-local optimizations and for quasi-global optimizations, indicating a good ability of the optimizer to find a solution with or without a well defined set of initial multipole settings.
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Transmitters and receivers in free space optical communications for Deep Space links
NASA Technical Reports Server (NTRS)
Beebe, J.
2003-01-01
Two of the many research areas integral making a Mars-Earth optical communication link a reality are optical antenna design and laser transmitter design. This paper addresses areas of both of these by exploring a mode-matched design for a cavity-dumped communications laser, and by reporting on the initial stages of the analysis of an existing 100 inch telescope for use as an optical communications receiver.