Evolution of Precipitation Structure During the November DYNAMO MJO Event: Cloud-Resolving Model Intercomparison and Cross Validation Using Radar Observations

NASA Astrophysics Data System (ADS)

Li, Xiaowen; Janiga, Matthew A.; Wang, Shuguang; Tao, Wei-Kuo; Rowe, Angela; Xu, Weixin; Liu, Chuntao; Matsui, Toshihisa; Zhang, Chidong

2018-04-01

Evolution of precipitation structures are simulated and compared with radar observations for the November Madden-Julian Oscillation (MJO) event during the DYNAmics of the MJO (DYNAMO) field campaign. Three ground-based, ship-borne, and spaceborne precipitation radars and three cloud-resolving models (CRMs) driven by observed large-scale forcing are used to study precipitation structures at different locations over the central equatorial Indian Ocean. Convective strength is represented by 0-dBZ echo-top heights, and convective organization by contiguous 17-dBZ areas. The multi-radar and multi-model framework allows for more stringent model validations. The emphasis is on testing models' ability to simulate subtle differences observed at different radar sites when the MJO event passed through. The results show that CRMs forced by site-specific large-scale forcing can reproduce not only common features in cloud populations but also subtle variations observed by different radars. The comparisons also revealed common deficiencies in CRM simulations where they underestimate radar echo-top heights for the strongest convection within large, organized precipitation features. Cross validations with multiple radars and models also enable quantitative comparisons in CRM sensitivity studies using different large-scale forcing, microphysical schemes and parameters, resolutions, and domain sizes. In terms of radar echo-top height temporal variations, many model sensitivity tests have better correlations than radar/model comparisons, indicating robustness in model performance on this aspect. It is further shown that well-validated model simulations could be used to constrain uncertainties in observed echo-top heights when the low-resolution surveillance scanning strategy is used.

Wanting to Be Different Predicts Nonmotivated Change: Actual-Desired Self-Discrepancies and Susceptibility to Subtle Change Inductions.

PubMed

DeMarree, Kenneth G; Rios, Kimberly; Randell, J Adam; Wheeler, S Christian; Reich, Darcy A; Petty, Richard E

2016-12-01

Actual-desired discrepancies in people's self-concepts represent structural incongruities in their self-representations that can lead people to experience subjective conflict. Theory and research suggest that structural incongruities predict susceptibility to subtle influences like priming and conditioning. Although typically examined for their motivational properties, we hypothesized that because self-discrepancies represent structural incongruities in people's self-concepts, they should also predict susceptibility to subtle influences on people's active self-views. Across three studies, we found that subtle change inductions (self-evaluative conditioning and priming) exerted greater impact on active self-perceptions and behavior as actual-desired self-discrepancies increased in magnitude. Exploratory analyses suggested that these changes occurred regardless of the compatibility of the change induction with individuals' desired self-views. © 2016 by the Society for Personality and Social Psychology, Inc.

Feature: Post Traumatic Stres Disorder PTSD: Symptoms, Diagnosis, Treatment

MedlinePlus

... Navigation Bar Home Current Issue Past Issues Feature PTSD Symptoms, Diagnosis , Treatment Past Issues / Winter 2009 Table ... Symptoms As with mild traumatic brain injury (TBI), PTSD symptoms can be very subtle. "For example, some ...

The dielectric signature of glass density

NASA Astrophysics Data System (ADS)

Rams-Baron, M.; Wojnarowska, Z.; Knapik-Kowalczuk, J.; Jurkiewicz, K.; Burian, A.; Wojtyniak, M.; Pionteck, J.; Jaworska, M.; Rodríguez-Tinoco, C.; Paluch, M.

2017-09-01

At present, we are witnessing a renewed interest in the properties of densified glasses prepared by isobaric cooling of a liquid at elevated pressure. As high-pressure densification emerges as a promising approach in the development of glasses with customized features, understanding and controlling their unique properties represent a contemporary scientific and technological goal. The results presented herein indicate that the applied high-pressure preparation route leads to a glassy state with higher density (˜1%) and a reduced free volume of about 7%. We show that these subtle structural changes remarkably influence the dielectric response and spectral features of β-relaxation in etoricoxib glass. Our study, combining dynamical and structural techniques, reveal that β-relaxation in etoricoxib is extremely sensitive to the variations in molecular packing and can be used to probe the changes in glass density. Such connection is technologically relevant and may advance further progress in the field.

Characterization of Isomeric Glycans by Reversed Phase Liquid Chromatography-Electronic Excitation Dissociation Tandem Mass Spectrometry

NASA Astrophysics Data System (ADS)

Tang, Yang; Wei, Juan; Costello, Catherine E.; Lin, Cheng

2018-04-01

The occurrence of numerous structural isomers in glycans from biological sources presents a severe challenge for structural glycomics. The subtle differences among isomeric structures demand analytical methods that can provide structural details while working efficiently with on-line glycan separation methods. Although liquid chromatography-tandem mass spectrometry (LC-MS/MS) is a powerful tool for mixture analysis, the commonly utilized collision-induced dissociation (CID) method often does not generate a sufficient number of fragments at the MS2 level for comprehensive structural characterization. Here, we studied the electronic excitation dissociation (EED) behaviors of metal-adducted, permethylated glycans, and identified key spectral features that could facilitate both topology and linkage determinations. We developed an EED-based, nanoscale, reversed phase (RP)LC-MS/MS platform, and demonstrated its ability to achieve complete structural elucidation of up to five structural isomers in a single LC-MS/MS analysis. [Figure not available: see fulltext.

Lamb wave detection of limpet mines on ship hulls.

PubMed

Bingham, Jill; Hinders, Mark; Friedman, Adam

2009-12-01

This paper describes the use of ultrasonic guided waves for identifying the mass loading due to underwater limpet mines on ship hulls. The Dynamic Wavelet Fingerprint Technique (DFWT) is used to render the guided wave mode information in two-dimensional binary images because the waveform features of interest are too subtle to identify in time domain. The use of wavelets allows both time and scale features from the original signals to be retained, and image processing can be used to automatically extract features that correspond to the arrival times of the guided wave modes. For further understanding of how the guided wave modes propagate through the real structures, a parallel processing, 3D elastic wave simulation is developed using the finite integration technique (EFIT). This full field, technique models situations that are too complex for analytical solutions, such as built up 3D structures. The simulations have produced informative visualizations of the guided wave modes in the structures as well as mimicking directly the output from sensors placed in the simulation space for direct comparison to experiments. Results from both drydock and in-water experiments with dummy mines are also shown.

Structure of the midcontinent basement. Topography, gravity, seismic, and remote sensing

NASA Technical Reports Server (NTRS)

Guinness, E. A.; Strebeck, J. W.; Arvidson, R. E.; Scholz, K.; Davies, G. F.

1981-01-01

Some 600,000 discrete Bouguer gravity estimates of the continental United States were spatially filtered to produce a continuous tone image. The filtered data were also digitally painted in color coded form onto a shaded relief map. The resultant image is a colored shaded relief map where the hue and saturation of a given image element is controlled by the value of the Bouguer anomaly. Major structural features (e.g., midcontinent gravity high) are readily discernible in these data, as are a number of subtle and previously unrecognized features. A linear gravity low that is approximately 120 to 150 km wide extends from southeastern Nebraska, at a break in the midcontinent gravity high, through the Ozark Plateau, and across the Mississippi embayment. The low is also aligned with the Lewis and Clark lineament (Montana to Washington), forming a linear feature of approximately 2800 km in length. In southeastern Missouri the gravity low has an amplitude of 30 milligals, a value that is too high to be explained by simple valley fill by sedimentary rocks.

Raman Spectroscopy Adds Complementary Detail to the High-Resolution X-Ray Crystal Structure of Photosynthetic PsbP from Spinacia oleracea

PubMed Central

Lapkouski, Mikalai; Hofbauerova, Katerina; Sovova, Zofie; Ettrichova, Olga; González-Pérez, Sergio; Dulebo, Alexander; Kaftan, David; Kuta Smatanova, Ivana; Revuelta, Jose L.; Arellano, Juan B.; Carey, Jannette; Ettrich, Rüdiger

2012-01-01

Raman microscopy permits structural analysis of protein crystals in situ in hanging drops, allowing for comparison with Raman measurements in solution. Nevertheless, the two methods sometimes reveal subtle differences in structure that are often ascribed to the water layer surrounding the protein. The novel method of drop-coating deposition Raman spectropscopy (DCDR) exploits an intermediate phase that, although nominally “dry,” has been shown to preserve protein structural features present in solution. The potential of this new approach to bridge the structural gap between proteins in solution and in crystals is explored here with extrinsic protein PsbP of photosystem II from Spinacia oleracea. In the high-resolution (1.98 Å) x-ray crystal structure of PsbP reported here, several segments of the protein chain are present but unresolved. Analysis of the three kinds of Raman spectra of PsbP suggests that most of the subtle differences can indeed be attributed to the water envelope, which is shown here to have a similar Raman intensity in glassy and crystal states. Using molecular dynamics simulations cross-validated by Raman solution data, two unresolved segments of the PsbP crystal structure were modeled as loops, and the amino terminus was inferred to contain an additional beta segment. The complete PsbP structure was compared with that of the PsbP-like protein CyanoP, which plays a more peripheral role in photosystem II function. The comparison suggests possible interaction surfaces of PsbP with higher-plant photosystem II. This work provides the first complete structural picture of this key protein, and it represents the first systematic comparison of Raman data from solution, glassy, and crystalline states of a protein. PMID:23071614

Information Structure Influences Depth of Syntactic Processing: Event-Related Potential Evidence for the Chomsky Illusion

PubMed Central

Wang, Lin; Bastiaansen, Marcel; Yang, Yufang; Hagoort, Peter

2012-01-01

Information structure facilitates communication between interlocutors by highlighting relevant information. It has previously been shown that information structure modulates the depth of semantic processing. Here we used event-related potentials to investigate whether information structure can modulate the depth of syntactic processing. In question-answer pairs, subtle (number agreement) or salient (phrase structure) syntactic violations were placed either in focus or out of focus through information structure marking. P600 effects to these violations reflect the depth of syntactic processing. For subtle violations, a P600 effect was observed in the focus condition, but not in the non-focus condition. For salient violations, comparable P600 effects were found in both conditions. These results indicate that information structure can modulate the depth of syntactic processing, but that this effect depends on the salience of the information. When subtle violations are not in focus, they are processed less elaborately. We label this phenomenon the Chomsky illusion. PMID:23110131

Information structure influences depth of syntactic processing: event-related potential evidence for the Chomsky illusion.

PubMed

Wang, Lin; Bastiaansen, Marcel; Yang, Yufang; Hagoort, Peter

2012-01-01

Information structure facilitates communication between interlocutors by highlighting relevant information. It has previously been shown that information structure modulates the depth of semantic processing. Here we used event-related potentials to investigate whether information structure can modulate the depth of syntactic processing. In question-answer pairs, subtle (number agreement) or salient (phrase structure) syntactic violations were placed either in focus or out of focus through information structure marking. P600 effects to these violations reflect the depth of syntactic processing. For subtle violations, a P600 effect was observed in the focus condition, but not in the non-focus condition. For salient violations, comparable P600 effects were found in both conditions. These results indicate that information structure can modulate the depth of syntactic processing, but that this effect depends on the salience of the information. When subtle violations are not in focus, they are processed less elaborately. We label this phenomenon the Chomsky illusion.

Protein functional features are reflected in the patterns of mRNA translation speed.

PubMed

López, Daniel; Pazos, Florencio

2015-07-09

The degeneracy of the genetic code makes it possible for the same amino acid string to be coded by different messenger RNA (mRNA) sequences. These "synonymous mRNAs" may differ largely in a number of aspects related to their overall translational efficiency, such as secondary structure content and availability of the encoded transfer RNAs (tRNAs). Consequently, they may render different yields of the translated polypeptides. These mRNA features related to translation efficiency are also playing a role locally, resulting in a non-uniform translation speed along the mRNA, which has been previously related to some protein structural features and also used to explain some dramatic effects of "silent" single-nucleotide-polymorphisms (SNPs). In this work we perform the first large scale analysis of the relationship between three experimental proxies of mRNA local translation efficiency and the local features of the corresponding encoded proteins. We found that a number of protein functional and structural features are reflected in the patterns of ribosome occupancy, secondary structure and tRNA availability along the mRNA. One or more of these proxies of translation speed have distinctive patterns around the mRNA regions coding for certain protein local features. In some cases the three patterns follow a similar trend. We also show specific examples where these patterns of translation speed point to the protein's important structural and functional features. This support the idea that the genome not only codes the protein functional features as sequences of amino acids, but also as subtle patterns of mRNA properties which, probably through local effects on the translation speed, have some consequence on the final polypeptide. These results open the possibility of predicting a protein's functional regions based on a single genomic sequence, and have implications for heterologous protein expression and fine-tuning protein function.

Fractal based modelling and analysis of electromyography (EMG) to identify subtle actions.

PubMed

Arjunan, Sridhar P; Kumar, Dinesh K

2007-01-01

The paper reports the use of fractal theory and fractal dimension to study the non-linear properties of surface electromyogram (sEMG) and to use these properties to classify subtle hand actions. The paper reports identifying a new feature of the fractal dimension, the bias that has been found to be useful in modelling the muscle activity and of sEMG. Experimental results demonstrate that the feature set consisting of bias values and fractal dimension of the recordings is suitable for classification of sEMG against the different hand gestures. The scatter plots demonstrate the presence of simple relationships of these features against the four hand gestures. The results indicate that there is small inter-experimental variation but large inter-subject variation. This may be due to differences in the size and shape of muscles for different subjects. The possible applications of this research include use in developing prosthetic hands, controlling machines and computers.

Visualizing spatial correlation: structural and electronic orders in iron-based superconductors on atomic scale

NASA Astrophysics Data System (ADS)

Maksov, Artem; Ziatdinov, Maxim; Li, Li; Sefat, Athena; Maksymovych, Petro; Kalinin, Sergei

Crystalline matter on the nanoscale level often exhibits strongly inhomogeneous structural and electronic orders, which have a profound effect on macroscopic properties. This may be caused by subtle interplay between chemical disorder, strain, magnetic, and structural order parameters. We present a novel approach based on combination of high resolution scanning tunneling microscopy/spectroscopy (STM/S) and deep data style analysis for automatic separation, extraction, and correlation of structural and electronic behavior which might lead us to uncovering the underlying sources of inhomogeneity in in iron-based family of superconductors (FeSe, BaFe2As2) . We identify STS spectral features using physically robust Bayesian linear unmixing, and show their direct relevance to the fundamental physical properties of the system, including electronic states associated with individual defects and impurities. We collect structural data from individual unit cells on the crystalline lattice, and calculate both global and local indicators of spatial correlation with electronic features, demonstrating, for the first time, a direct quantifiable connection between observed structural order parameters extracted from the STM data and electronic order parameters identified within the STS data. This research was sponsored by the Division of Materials Sciences and Engineering, Office of Science, Basic Energy Sciences, US DOE.

White light emission and second harmonic generation from secondary group participation (SGP) in a coordination network.

PubMed

He, Jun; Zeller, Matthias; Hunter, Allen D; Xu, Zhengtao

2012-01-25

We describe a white emitting coordination network solid that can be conveniently applied as a thin film onto a commercial UV-LED lamp for practical white lighting applications. The solid state material was discovered in an exercise of exploring molecular building blocks equipped with secondary groups for fine-tuning the structures and properties of coordination nets. Specifically, CH(3)SCH(2)CH(2)S- and (S)-CH(3)(OH)CHCH(2)S- (2-hydroxylpropyl) were each attached as secondary groups to the 2,5- positions of 1,4-benzenedicarboxylic acid (bdc), and the resultant molecules (L1 and L2, respectively) were crystallized with Pb(II) into the topologically similar 3D nets of PbL1 and PbL2, both consisting of interlinked Pb-carboxyl chains. While the CH(3)S- groups in PbL1 are not bonded to the Pb(II) centers, the hydroxy groups in PbL2 participate in coordinating to Pb(II) and thus modify the bonding features around the Pb(II), but only to a slight and subtle degree (e.g., Pb-O distances 2.941-3.116 Å). Interestingly, the subtle change in structure significantly impacts the properties, i.e., while the photoluminescence of PbL1 is yellowish green, PbL2 features bright white emission. Also, the homochiral side group in PbL2 imparts significant second harmonic generation, in spite of its seemingly weak association with the main framework (the NLO-phore). In a broad perspective, this work showcases the idea of secondary group participation (SGP) in the construction of coordination networks, an idea that parallels that of hemilabile ligands in organometallics and points to an effective strategy in developing advanced functions in solid state framework materials. © 2011 American Chemical Society

Invisible Colors of the Moon

NASA Image and Video Library

2009-09-24

Data from NASA Moon Mineralogy Mapper instrument on the Indian Space Research Organization Chandrayaan-1 spacecraft reveal subtle and previously unknown lunar diversity and features. Animation available at the Photojournal.

High-resolution charge carrier mobility mapping of heterogeneous organic semiconductors

NASA Astrophysics Data System (ADS)

Button, Steven W.; Mativetsky, Jeffrey M.

2017-08-01

Organic electronic device performance is contingent on charge transport across a heterogeneous landscape of structural features. Methods are therefore needed to unravel the effects of local structure on overall electrical performance. Using conductive atomic force microscopy, we construct high-resolution out-of-plane hole mobility maps from arrays of 5000 to 16 000 current-voltage curves. To demonstrate the efficacy of this non-invasive approach for quantifying and mapping local differences in electrical performance due to structural heterogeneities, we investigate two thin film test systems, one bearing a heterogeneous crystal structure [solvent vapor annealed 5,11-Bis(triethylsilylethynyl)anthradithiophene (TES-ADT)—a small molecule organic semiconductor] and one bearing a heterogeneous chemical composition [p-DTS(FBTTh2)2:PC71BM—a high-performance organic photovoltaic active layer]. TES-ADT shows nearly an order of magnitude difference in hole mobility between semicrystalline and crystalline areas, along with a distinct boundary between the two regions, while p-DTS(FBTTh2)2:PC71BM exhibits subtle local variations in hole mobility and a nanoscale domain structure with features below 10 nm in size. We also demonstrate mapping of the built-in potential, which plays a significant role in organic light emitting diode and organic solar cell operation.

Access to Formally Ni(I) States in a Heterobimetallic NiZn System

PubMed Central

Uyeda, Christopher

2014-01-01

Heterobimetallic NiZn complexes featuring metal centers in distinct coordination environments have been synthesized using diimine-dioxime ligands as binucleating scaffolds. A tetramethylfuran-containing ligand derivative enables a stable one-electron-reduced S = 1/2 species to be accessed using Cp2Co as a chemical reductant. The resulting pseudo-square planar complex exhibits spectroscopic and crystallographic characteristics of a ligand-centered radical bound to a Ni(II) center. Upon coordination of a π-acidic ligand such as PPh3, however, a five-coordinate Ni(I) metalloradical is formed. The electronic structures of these reduced species provide insight into the subtle effects of ligand structure on the potential and reversibility of the NiII/I couple for complexes of redox-active tetraazamacrocycles. PMID:25614786

Evolution of planetary lithospheres - Evidence from multiringed structures on Ganymede and Callisto

NASA Technical Reports Server (NTRS)

Mckinnon, W. B.; Melosh, H. J.

1980-01-01

The thickness and viscosity of a planetary lithosphere increase with time as the mantle cools, with a thicker lithosphere leading to the formation of one (or very few) irregular normal faults concentric to the crater. Since a gravity wave or tsunami induced by impact into a liquid mantle would result in both radial and concentric extension features, which are not observed in the case of the large impact structures on Ganymede and Callisto, an alternative mechanism is proposed in which the varying ice/silicate ratios, tectonic histories, and erosional mechanisms of the two bodies are considered to explain the subtle differences in thin lithosphere ring morphology between Ganymede and Callisto. It is concluded that the present lithosphere thickness of Ganymede is too great to permit the development of any rings.

Subtle Sex-Role Cues in Children's Commercials.

ERIC Educational Resources Information Center

And Others; Welch, Renate L.

1979-01-01

Examines forms of communication used in commercials to convey social stereotypes. (Forms refer to production techniques such as level of action or movement, pacing, camera techniques, and auditory features.) (PD)

Detection of subtle nocturnal motor activity from 3-D accelerometry recordings in epilepsy patients.

PubMed

Nijsen, Tamara M E; Cluitmans, Pierre J M; Arends, Johan B A M; Griep, Paul A M

2007-11-01

This paper presents a first step towards reliable detection of nocturnal epileptic seizures based on 3-D accelerometry (ACM) recordings. The main goal is to distinguish between data with and without subtle nocturnal motor activity, thus reducing the amount of data that needs further (more complex) analysis for seizure detection. From 15 ACM signals (measured on five positions on the body), two features are computed, the variance and the jerk. In the resulting 2-D feature space, a linear threshold function is used for classification. For training and testing, the algorithm ACM data along with video data is used from nocturnal registrations in seven mentally retarded patients with severe epilepsy. Per patient, the algorithm detected 100% of the periods of motor activity that are marked in video recordings and the ACM signals by experts. From all the detections, 43%-89% was correct (mean =65%). We were able to reduce the amount of data that need to be analyzed considerably. The results show that our approach can be used for detection of subtle nocturnal motor activity. Furthermore, our results indicate that our algorithm is robust for fluctuations across patients. Consequently, there is no need for training the algorithm for each new patient.

Genetic variability, individuality and the evolution of the mammalian brain.

PubMed

Lipp, H P

1995-12-01

The neo-Darwinian theory of evolution has difficulty in explaining the rapid evolution of mammalian brain and behavior. I shall argue that the plasticity mechanisms of the brain (i.e., system homeostasis, developmental reorganization, structural adult plasticity, and cognition and learning) have evolved primarily as genetic buffer systems which protect subtle mutations influencing brain structures from natural selection. These buffer systems permit accumulation of genetic variation in the higher system levels of the brain (simply defined as structures with late differentiation), while low-level systems are kept constant by natural selection. The organization of this intrinsic genetic buffering system provides several features facilitating neo-Darwinian evolution: In conclusion, the evolutionary appearance of cognition and intelligence is an ordinary biological mechanism compensating evolutionary drags such as long lifespans and fewer offspring. The concept has heuristic value for identifying gene-brain-behavior relationships and for explaining behavioral consequences of artifical gene deletions.

Self-consistent electronic structure of disordered Fe/sub 0. 65/Ni/sub 0. 35/

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, D.D.; Pinski, F.J.; Stocks, G.M.

1985-04-15

We present the results of the first ab initio calculation of the electronic structure of the disordered alloy Fe/sub 0.65/Ni/sub 0.35/. The calculation is based on the multiple-scattering coherent-potential approach (KKR-CPA) and is fully self-consistent and spin polarized. Magnetic effects are included within local-spin-density functional theory using the exchange-correlation function of Vosko--Wilk--Nusair. The most striking feature of the calculation is that electrons of different spins experience different degrees of disorder. The minority spin electrons see a very large disorder, whereas the majority spin electrons see little disorder. Consequently, the minority spin density of states is smooth compared to the verymore » structured majority spin density of states. This difference is due to a subtle balance between exchange splitting and charge neutrality.« less

Self-consistent electronic structure of disordered Fe/sub 0/ /sub 65/Ni/sub 0/ /sub 35/

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, D.D.; Pinski, F.J.; Stocks, G.M.

1984-01-01

We present the results of the first ab-initio calculation of the electronic structure of a disordered Fe/sub 0/ /sub 65/Ni/sub 0/ /sub 35/ alloy. The calculation is based on the multiple-scattering coherent-potential approach (KKR-CPA) and is fully self-consistent and spin-polarized. Magnetic effects are included within local-spin-density functional theory using the exchange-correlation function of Vosko-Wilk-Nusair. The most striking feature of the calculation is that electrons of different spins experience different degrees of disorder. The minority spin electrons see a very large disorder; whereas, the majority spin electrons see little disorder. Consequently, the minority spin density of states is smooth compared tomore » the very structured majority spin density of states. This difference is due to a subtle balance between exchange-splitting and charge neutrality. 15 references, 2 figures.« less

Neutron studies of paramagnetic fullerenols’ assembly in aqueous solutions

NASA Astrophysics Data System (ADS)

Lebedev, V. T.; Szhogina, A. A.; Suyasova, M. V.

2018-03-01

Recent results on structural studies of aqueous solutions of water-soluble derivatives of endofullerenes encapsulating 4f- and 3d-elements have been presented. Neutron small angle scattering experiments allowed recognize subtle features of fullerenols assembly as dependent on chemical nature (atomic number) of interior atom, pH-factor and temperature of solutions. It was observed a fractal-type fullerenols’ ordering at the scale of correlation radii ∼ 10-20 nm when molecules with iron atoms are integrated into branched structures at low concentrations (C ≤ 1 % wt.) and organized into globular aggregates at higher amounts (C > 1 % wt.). On the other hand, for Lanthanides captured in carbon cages the supramolecular structures are mostly globular and have larger gyration radii ∼ 30 nm. They demonstrated a good stability in acidic (pH ∼ 3) and neutral (pH ∼ 7) media that is important for forthcoming medical applications.

The Atmosphere of Uranus as Imaged with Keck Adaptive Optics

NASA Astrophysics Data System (ADS)

Hammel, H. B.; de Pater, I.; Gibbard, S. G.; Lockwood, G. W.; Rages, K.

2004-12-01

Adaptive optics imaging of Uranus was obtained with NIRC2 on the Keck II 10-meter telescope in October 2003 and July 2004 through J, H, and K' filters. Dozens of discrete features were detected in the atmosphere of Uranus. We report the first measurements of winds northward of +43 deg, the first direct measurement of equatorial winds, and the highest wind velocity seen yet on Uranus. At northern mid-latitudes, the winds may have accelerated when compared to earlier HST and Keck observations; southern wind speeds have not changed since Voyager measurements in 1986. The equator of Uranus exhibits a subtle wave structure, with diffuse patches roughly every 30 degs in longitude. There is no sign of a northern "polar collar" as is seen in the south, but a number of discrete features seen at the "expected" latitudes may signal its early stages of development. The largest cloud features on Uranus show complex structure extending over tens of degrees. On 4 July 2004, we detected a southern hemispheric cloud feature on Uranus at K', the first detection of a southern feature at or longward of 2 microns. H images showed an extended structure whose condensed core was co-located with the K'-bright feature. The core exhibited marked brightness variation, fading within just a few days. The initial brightness at K' indicates that the core's scattering particles reached altitudes above the 1-bar level, with the extended H feature residing below 1.1 bars. The core's rapid disappearance at K' indicates dynamical processes in the local vertical aerosol structure. HBH acknowledges support from NASA grants NAG5-11961 and NAG5-10451. IdP acknowledges support from NSF and the Technology Center for Adaptive Optics, managed by UCSC under cooperative agreement No. AST-9876783. SGG's work was performed under the auspices of the U.S. DoE National Nuclear Security Administration by the UC, LLNL under contract No. W-7405-Eng-48.

Lake Superior as seen from Skylab

NASA Image and Video Library

1974-01-06

SL4-139-3953 (7 Jan. 1974) --- An oblique view of a portion of the Middle West looking northeastward toward Lake Superior and Ontario, Canada, as seen from the Skylab space station in Earth orbit. This picture was taken by one of the Skylab 4 crewmen with a hand-held 70mm Hasselblad camera using a 100mm lens. Most of the land mass in the foreground is Wisconsin. Iowa is in the lower left corner. Minnesota is at left and upper left. Ontario is in the far right background. Michigan is at right center. Note the circular-shaped feature at center left which was first observed by the Skylab 4 crewmen. The feature is 85 kilometers (55 miles) in diameter, and it is centered near 91.5 degrees west longitude and 44.5 degrees north latitude. The Mississippi River Valley forms the southwest side of the circular feature. The City of La Crosse, Wisconsin, is just south of the near side of the circle, and the Black River completes the southern and eastern part. The City of Eau Claire is at the north edge of the circle. The most likely origin of circular features of this magnitude are (1) volcanic, (2) structural, or (3) meteorite impact. The feature is not volcanic -- the rocks are the wrong type. Possibly it is structural, formed by slight warping of layered rocks into a basin or dome, followed by erosion of all but the most subtle trace of the structure. The feature could be a severely eroded meteorite impact crater. If so, a thorough study of the area may yield evidence of the extreme pressure and temperature the rocks were subjected to by the shock of an impacting meteorite. Photo credit: NASA

Unraveling Appalachian tectonics: domain analysis of topographic lineaments in Pennsylvania

NASA Astrophysics Data System (ADS)

Karimi, B.; Schon, K.; Nussbaum, G. W.; Storer, N. D.; McGuire, J. L.; Hardcastle, K.

2016-12-01

Litho-tectonic provinces provide different components of a regions' tectonic history, and are identified as spatial entities with common structural elements, or a number of contiguous related elements. The province boundaries are easily identified when geomorphic expressions are distinct, or significant rock exposure allows for little uncertainty. When exposures are limited, locations of boundaries between provinces are uncertain. In such instances, satellite imagery can be quite advantageous, as tectonically sourced features (faults, folds, fractures, and joints) may exert a strong control on topographic patterns by creating pathways for weathering and erosion. Lineament analyses of topography often focus on well-pronounced tectonic features to interpret regional tectonics. We suggest that lineament analyses including all topographic features may include more subtle tectonic features, resulting in the identification of minor heterogeneities within litho-tectonic provinces. Our study focuses on Appalachian tectonics, specifically in Pennsylvania (PA), home to the Appalachian Orocline and 5 distinct tectonic provinces. Using hillshades from a digital elevation model (DEM) of PA, we manually pick all topographic lineaments 1 km or greater, discriminating only against man-made structures. The final lineament coverage of the state is subdivided into smaller areas for which rose diagrams were prepared. The dominant lineament trends were compared and associated with known structural features. Peaks with no known source are marked as possible tectonic features requiring further research. A domain analysis is performed on the lineament data to identify the extent and interplay of swarms, followed by an investigation of their azimuthal compatibility. We present the results of our domain analysis of all topographic lineaments in the context of identifying litho-tectonic provinces associated with Appalachian tectonics in Pennsylvania, and possible heterogeneities within them.

Ultrafast studies of coexisting electronic order in cuprate superconductors

NASA Astrophysics Data System (ADS)

Hinton, James; Thewalt, Eric; Alpichshev, Zhanybek; Sternbach, Aaron; McLeod, Alex; Ji, L.; Veit, Mike; Dorrow, Chelsey; Koralek, Jake; Xhao, Xudong; Barisic, Neven; Kemper, Alexander; Gedik, Nuh; Greven, Martin; Basov, Dimitri; Orenstein, Joe

The cuprate family of high temperature superconductors displays a variety of electronic phases which emerge when charge carriers are added to the antiferromagnetic parent compound. These electronic phases are characterized by subtle differences in the low energy electronic excitations. Ultrafast time-resolved reflectivity (TRR) provides an ideal tool for investigating the cuprate phase diagram, as small changes in the electronic structure can produce significant contrast in the non-equilibrium reflectivity. Here we present TRR measurements of cuprate superconductors, focusing on the model single-layer cuprate HgBa2CuO4+δ. We observe a cusp-like feature in the quasiparticle lifetime near the superconducting transition temperature Tc. This feature can be understood using a model of coherently-mixed charge-density wave and superconducting pairing. We propose extending this technique to the nanoscale using ultrafast scattering scanning near-field microscopy (u-SNOM). This will allow us to explore how these electronic phases coexist and compete in real-space.

SUBTLE: Situation Understanding Bot through Language and Environment

DTIC Science & Technology

2016-01-06

a 4 day “hackathon” by Stuart Young’s small robots group which successfully ported the SUBTLE MURI NLP robot interface to the Packbot platform they...null element restoration, a step typically ig- nored in NLP systems, allows for correct parsing of im- peratives and questions, critical structures

Structure of adeno-associated virus-2 in complex with neutralizing monoclonal antibody A20

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCraw, Dustin M.; O'Donnell, Jason K.; Taylor, Kenneth A.

2012-09-15

The use of adeno-associated virus (AAV) as a gene therapy vector is limited by the host neutralizing immune response. The cryo-electron microscopy (EM) structure at 8.5 A resolution is determined for a complex of AAV-2 with the Fab' fragment of monoclonal antibody (MAb) A20, the most extensively characterized AAV MAb. The binding footprint is determined through fitting the cryo-EM reconstruction with a homology model following sequencing of the variable domain, and provides a structural basis for integrating diverse prior epitope mappings. The footprint extends from the previously implicated plateau to the side of the spike, and into the conserved canyon,more » covering a larger area than anticipated. Comparison with structures of binding and non-binding serotypes indicates that recognition depends on a combination of subtle serotype-specific features. Separation of the neutralizing epitope from the heparan sulfate cell attachment site encourages attempts to develop immune-resistant vectors that can still bind to target cells.« less

Characterizing complex structural variation in germline and somatic genomes

PubMed Central

Quinlan, Aaron R.; Hall, Ira M.

2011-01-01

Genome structural variation (SV) is a major source of genetic diversity in mammals and a hallmark of cancer. While SV is typically defined by its canonical forms – duplication, deletion, insertion, inversion and translocation – recent breakpoint mapping studies have revealed a surprising number of “complex” variants that evade simple classification. Complex SVs are defined by clustered breakpoints that arose through a single mutation but cannot be explained by one simple end-joining or recombination event. Some complex variants exhibit profoundly complicated rearrangements between distinct loci from multiple chromosomes, while others involve more subtle alterations at a single locus. These diverse and unpredictable features present a challenge for SV mapping experiments. Here, we review current knowledge of complex SV in mammals, and outline techniques for identifying and characterizing complex variants using next-generation DNA sequencing. PMID:22094265

Geology of Utah and Nevada by ERTS-1 imagery

NASA Technical Reports Server (NTRS)

Jensen, M. L.

1973-01-01

Repetitive ERTS-1 imagery covering Utah and Nevada is studied as an aid in structural geology, mineral exploration, and limnological and hydrological aspects. Limnological features of algal blooms and varying biological activities in Utah Lake and the Great Salt Lake are grossly evident on the imagery with more subtle details detected on the different bands. Major structural breaks, lineages, or trends are abundant throughout the area of study. The correlation of positive aeromagnetic anomalies with the trends suggests near surface intrusive bodies, not yet exposed at the surface, that can be tested for possible associated mineralization by collecting soil-gas at the surface which is analyzed for mercury that is (1) apparently associated with mineralization, (2) escapes as a vapor, and (3) can be readily measured in extremely low amounts of less than 1 ppb by absorption.

Stem cell behavior on tailored porous oxide surface coatings.

PubMed

Lavenus, Sandrine; Poxson, David J; Ogievetsky, Nika; Dordick, Jonathan S; Siegel, Richard W

2015-07-01

Nanoscale surface topographies are known to have a profound influence on cell behavior, including cell guidance, migration, morphology, proliferation, and differentiation. In this study, we have observed the behavior of human mesenchymal stem cells cultured on a range of tailored porous SiO2 and TiO2 nanostructured surface coatings fabricated via glancing angle electron-beam deposition. By controlling the physical vapor deposition angle during fabrication, we could control systematically the deposited coating porosity, along with associated topographic features. Immunocytochemistry and image analysis quantitatively revealed the number of adherent cells, as well as their basic cellular morphology, on these surfaces. Signaling pathway studies showed that even with subtle changes in nanoscale surface structures, the behavior of mesenchymal stem cells was strongly influenced by the precise surface structures of these porous coatings. Copyright © 2015 Elsevier Ltd. All rights reserved.

Geologic interpretation of space shuttle radar images of Indonesia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sabing, F.F.

1983-11-01

The National Aeronautics and Space Administration (NASA) space shuttle mission in November 1981 acquired images of parts of the earth with a synthetic aperture radar system at a wavelength of 23.5 cm (9.3 in.) and spatial resolution of 38 m (125 ft). This report describes the geologic interpretation of 1:250,000-scale images of Irian Jaya and eastern Kalimantan, Indonesia, where the all-weather capability of radar penetrates the persistent cloud cover. The inclined look direction of radar enhances subtle topographic features that may be the expression of geologic structures. On the Indonesian images, the following terrain categories are recognizable for geologic mapping:more » carbonate, clastic, volcanic, alluvial and coastal, melange, and metamorphic, as well as undifferentiated bedrock. Regional and local geologic structures are well expressed on the images.« less

Self-esteem and other-esteem in college students with borderline and avoidant personality disorder features: An experimental vignette study.

PubMed

Bowles, David P; Armitage, Chris J; Drabble, Jennifer; Meyer, Björn

2013-11-01

An experimental study investigated self-esteem and other-esteem responses to either fully supportive or less supportive interpersonal feedback in college students with avoidant and borderline personality disorder features (APD and BPD respectively). Disturbances in self-esteem and in evaluations of others are central to definitions of both APD and BPD, but the extent to which such interpersonal appraisals are responsive to contextual features, such as evaluative feedback from others, is not yet clear. In theory, we would expect that individuals with pronounced PD features would show more inflexible and more negative self-evaluations and others- evaluations than those without PD features. In this study with 169 undergraduates, APD but not BPD features were associated with other-contingent state self-esteem and other-esteem. A significant interaction indicated that highly avoidant respondents felt particularly negatively about themselves and their close others in situations that conveyed subtle criticism but not in situations signalling unequivocal support. This suggests that their self-esteem and other-esteem, rather than being rigidly negative, are instead highly contingent upon interpersonal feedback. Such context contingency has implications for the trait-like description of diagnostic characteristics within current taxonomies and is in line with contemporary dynamic models of personality structure and process. Copyright © 2013 John Wiley & Sons, Ltd.

[Dynamics of child suggestibility in accusations of sexual abuse in divorce proceedings].

PubMed

du Bois, R; Röcker, D

1996-11-01

A case of a mother confabulating an extended sexual abuse of her 13 and 15 year old children involving bizarre sadistic features is presented and discussed. The kinship to Munchhausen Syndrome by proxy, identity diffusion, Posttraumatic Stress Syndrome, folie à deux and other concepts is highlighted. It is suggested that sexual confabulations are generated within incestuous family structures as a means to stimulate and satisfy needs of personal closeness when losses and disruptive events have occurred. The disclosure or suspicion of sexual abuse may prove neither true nor false but may hint to an impending emotional breakdown of a parent and to ongoing subtle incestuous traumatisation of a child.

IMAGING SPECTROSCOPY FOR DETERMINING RANGELAND STRESSORS TO WESTERN WATERSHEDS

EPA Science Inventory

The Environmental Protection Agency is developing rangeland ecological indicators in twelve western states using advanced remote sensing techniques. Fine spectral resolution (hyperspectral) sensors, or imaging spectrometers, can detect the subtle spectral features that make veget...

IMAGING SPECTROSCOPY FOR DETERMINING RANGELAND STRESSORS TO WESTERN WATERSHEDS

EPA Science Inventory

The Environmental Protection Agency is developing rangeland ecological indicators in eleven western states using advanced remote sensing systems. Fine spectral resolution (hyperspemal) sensors, or imaging spectrometers, can detect the subtle spectral features that makes vegetatio...

Automated Detection of Diabetic Retinopathy using Deep Learning.

PubMed

Lam, Carson; Yi, Darvin; Guo, Margaret; Lindsey, Tony

2018-01-01

Diabetic retinopathy is a leading cause of blindness among working-age adults. Early detection of this condition is critical for good prognosis. In this paper, we demonstrate the use of convolutional neural networks (CNNs) on color fundus images for the recognition task of diabetic retinopathy staging. Our network models achieved test metric performance comparable to baseline literature results, with validation sensitivity of 95%. We additionally explored multinomial classification models, and demonstrate that errors primarily occur in the misclassification of mild disease as normal due to the CNNs inability to detect subtle disease features. We discovered that preprocessing with contrast limited adaptive histogram equalization and ensuring dataset fidelity by expert verification of class labels improves recognition of subtle features. Transfer learning on pretrained GoogLeNet and AlexNet models from ImageNet improved peak test set accuracies to 74.5%, 68.8%, and 57.2% on 2-ary, 3-ary, and 4-ary classification models, respectively.

Fractal Complexity-Based Feature Extraction Algorithm of Communication Signals

NASA Astrophysics Data System (ADS)

Wang, Hui; Li, Jingchao; Guo, Lili; Dou, Zheng; Lin, Yun; Zhou, Ruolin

How to analyze and identify the characteristics of radiation sources and estimate the threat level by means of detecting, intercepting and locating has been the central issue of electronic support in the electronic warfare, and communication signal recognition is one of the key points to solve this issue. Aiming at accurately extracting the individual characteristics of the radiation source for the increasingly complex communication electromagnetic environment, a novel feature extraction algorithm for individual characteristics of the communication radiation source based on the fractal complexity of the signal is proposed. According to the complexity of the received signal and the situation of environmental noise, use the fractal dimension characteristics of different complexity to depict the subtle characteristics of the signal to establish the characteristic database, and then identify different broadcasting station by gray relation theory system. The simulation results demonstrate that the algorithm can achieve recognition rate of 94% even in the environment with SNR of -10dB, and this provides an important theoretical basis for the accurate identification of the subtle features of the signal at low SNR in the field of information confrontation.

Continuing the conversation in nursing on race and racism.

PubMed

Hall, Joanne M; Fields, Becky

2013-01-01

Nursing values include diversity and a commitment to the elimination of health disparities. However, nursing comprises predominantly white, female nurses. The authors explore structural and interpersonal sources of disparities experienced by black persons, including white privilege. Here, the authors advocate for a continuation of the racism conversation, specifically among white nurses. Racial disadvantages stem from structural inequalities from daily slights, and usually unintended subtle racism toward black people on the part of white people, including white nurses. By raising consciousness on how we propagate subtle racism, nursing can progress faster in eliminating health disparities. Topics include postracialism, colorblindness, institutional racism, white privilege, health disparities, clinical encounters, subtle racism, and racial microaggressions. Suggestions for open dialogue, historical awareness, education, research, and practice are highlighted. Difficulties involved in confronting racism and white privilege are explored. Copyright © 2013 Elsevier Inc. All rights reserved.

Why Are Some GCSE Examination Questions Harder to Mark Accurately than Others? Using Kelly's Repertory Grid Technique to Identify Relevant Question Features

ERIC Educational Resources Information Center

Suto, W. M. Irenka; Nadas, Rita

2009-01-01

It has long been established that marking accuracy in public examinations varies considerably among subjects and markers. This is unsurprising, given the diverse cognitive strategies that the marking process can entail, but what makes some questions harder to mark accurately than others? Are there distinct but subtle features of questions and…

A scanning acoustic microscope discriminates cancer cells in fluid

NASA Astrophysics Data System (ADS)

Miura, Katsutoshi; Yamamoto, Seiji

2015-10-01

Scanning acoustic microscopy (SAM) discriminates lesions in sections by assessing the speed of sound (SOS) or attenuation of sound (AOS) through tissues within a few minutes without staining; however, its clinical use in cytological diagnosis is unknown. We applied a thin layer preparation method to observe benign and malignant effusions using SAM. Although SAM is inferior in detecting nuclear features than light microscopy, it can differentiate malignant from benign cells using the higher SOS and AOS values and large irregular cell clusters that are typical features of carcinomas. Moreover, each single malignant cell exhibits characteristic cytoplasmic features such as a large size, irregular borders and secretory or cytoskeletal content. By adjusting the observation range, malignant cells are differentiated from benign cells easily using SAM. Subtle changes in the functional and structural heterogeneity of tumour cells were pursuable with a different digital data of SAM. SAM can be a useful tool for screening malignant cells in effusions before light microscopic observation. Higher AOS values in malignant cells compared with those of benign cells support the feasibility of a novel sonodynamic therapy for malignant effusions.

Overt and Subtle Racial Discrimination and Mental Health: Preliminary Findings for Korean Immigrants

PubMed Central

Noh, Samuel; Kaspar, Violet; Wickrama, K.A.S.

2007-01-01

Objectives. We examined differential effects of overt and subtle forms of racial discrimination on 2 dimensions of mental health—positive affect and depressive symptoms, and explored the mediating roles of emotional arousal and cognitive appraisal. Methods. Cross-sectional survey data were collected through face-to-face interviews with a sample (N=180) of adult Korean immigrants living in Toronto, Ontario. Maximum likelihood estimates of path coefficients were obtained using structural equation models. Results. Perceived racial discrimination was associated with both the erosion of positive affect and depressive symptoms. Overt discrimination was associated with the erosion of positive affect, and subtle discrimination was associated with depressive symptoms. Effects of subtle discrimination on depressive symptoms were mediated through cognitive appraisal. Conclusions. The results emphasize the salience of subtle discrimination for the mental health of Asian immigrants. Experiences of overt racial bias seemed to be of little importance for the levels of depressive symptoms among those in our sample, although the experience of blatant discrimination tended to reduce positive mood. PMID:17538066

Forms of ethnic prejudice: assessing the dimensionality of a Spanish-language version of the Blatant and Subtle Prejudice Scale.

PubMed

Cárdenas Castro, Manuel

2010-02-01

The main purpose of this study was to investigate the dimensionality of a Spanish-language version of the Blatant and Subtle Prejudice Scale via exploratory (EFA) and confirmatory factor analysis (CFA). No research has confirmed the hypothesized factor structure in Latin American countries. Using data from a random and probability survey in population of the northern area of Chile (N= 896), four models were specified: single factor model (global prejudice factor), correlated two-factor model (subtle and blatant prejudice), correlated two-factor second-order model, and single-factor second-order model. The findings indicated that the two-factor second-order model had the best fit. The corresponding alpha coefficients were .82 (subtle prejudice) and .76 (blatant prejudice). Lastly, differences were examined between , , and regarding their feelings toward immigrants, their feelings about their beliefs concerning the state aid received by these out-groups, and their feelings about their beliefs regarding future policies for them.

Dark matter phenomenology of high-speed galaxy cluster collisions

DOE PAGES

Mishchenko, Yuriy; Ji, Chueng-Ryong

2017-07-29

Here, we perform a general computational analysis of possible post-collision mass distributions in high-speed galaxy cluster collisions in the presence of self-interacting dark matter. Using this analysis, we show that astrophysically weakly self-interacting dark matter can impart subtle yet measurable features in the mass distributions of colliding galaxy clusters even without significant disruptions to the dark matter halos of the colliding galaxy clusters themselves. Most profound such evidence is found to reside in the tails of dark matter halos’ distributions, in the space between the colliding galaxy clusters. Such features appear in our simulations as shells of scattered dark mattermore » expanding in alignment with the outgoing original galaxy clusters, contributing significant densities to projected mass distributions at large distances from collision centers and large scattering angles of up to 90°. Our simulations indicate that as much as 20% of the total collision’s mass may be deposited into such structures without noticeable disruptions to the main galaxy clusters. Such structures at large scattering angles are forbidden in purely gravitational high-speed galaxy cluster collisions.Convincing identification of such structures in real colliding galaxy clusters would be a clear indication of the self-interacting nature of dark matter. Our findings may offer an explanation for the ring-like dark matter feature recently identified in the long-range reconstructions of the mass distribution of the colliding galaxy cluster CL0024+017.« less

Dark matter phenomenology of high-speed galaxy cluster collisions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mishchenko, Yuriy; Ji, Chueng-Ryong

Here, we perform a general computational analysis of possible post-collision mass distributions in high-speed galaxy cluster collisions in the presence of self-interacting dark matter. Using this analysis, we show that astrophysically weakly self-interacting dark matter can impart subtle yet measurable features in the mass distributions of colliding galaxy clusters even without significant disruptions to the dark matter halos of the colliding galaxy clusters themselves. Most profound such evidence is found to reside in the tails of dark matter halos’ distributions, in the space between the colliding galaxy clusters. Such features appear in our simulations as shells of scattered dark mattermore » expanding in alignment with the outgoing original galaxy clusters, contributing significant densities to projected mass distributions at large distances from collision centers and large scattering angles of up to 90°. Our simulations indicate that as much as 20% of the total collision’s mass may be deposited into such structures without noticeable disruptions to the main galaxy clusters. Such structures at large scattering angles are forbidden in purely gravitational high-speed galaxy cluster collisions.Convincing identification of such structures in real colliding galaxy clusters would be a clear indication of the self-interacting nature of dark matter. Our findings may offer an explanation for the ring-like dark matter feature recently identified in the long-range reconstructions of the mass distribution of the colliding galaxy cluster CL0024+017.« less

An unconventional family 1 uracil DNA glycosylase in Nitratifractor salsuginis.

PubMed

Li, Jing; Chen, Ran; Yang, Ye; Zhang, Zhemin; Fang, Guang-Chen; Xie, Wei; Cao, Weiguo

2017-12-01

The uracil DNA glycosylase superfamily consists of at least six families with a diverse specificity toward DNA base damage. Family 1 uracil N-glycosylase (UNG) exhibits exclusive specificity on uracil-containing DNA. Here, we report a family 1 UNG homolog from Nitratifractor salsuginis with distinct biochemical features that differentiate it from conventional family 1 UNGs. Globally, the crystal structure of N. salsuginisUNG shows a few additional secondary structural elements. Biochemical and enzyme kinetic analysis, coupled with structural determination, molecular modeling, and molecular dynamics simulations, shows that N. salsuginisUNG contains a salt bridge network that plays an important role in DNA backbone interactions. Disruption of the amino acid residues involved in the salt bridges greatly impedes the enzymatic activity. A tyrosine residue in motif 1 (GQDPY) is one of the distinct sequence features setting family 1 UNG apart from other families. The crystal structure of Y81G mutant indicates that several subtle changes may account for its inactivity. Unlike the conventional family 1 UNG enzymes, N. salsuginisUNG is not inhibited by Ugi, a potent inhibitor specific for family 1 UNG. This study underscores the diversity of paths that a uracil DNA glycosylase may take to acquire its unique structural and biochemical properties during evolution. Structure data are available in the PDB under accession numbers 5X3G and 5X3H. © 2017 Federation of European Biochemical Societies.

Peroxisome protein import: a complex journey.

PubMed

Baker, Alison; Lanyon-Hogg, Thomas; Warriner, Stuart L

2016-06-15

The import of proteins into peroxisomes possesses many unusual features such as the ability to import folded proteins, and a surprising diversity of targeting signals with differing affinities that can be recognized by the same receptor. As understanding of the structure and function of many components of the protein import machinery has grown, an increasingly complex network of factors affecting each step of the import pathway has emerged. Structural studies have revealed the presence of additional interactions between cargo proteins and the PEX5 receptor that affect import potential, with a subtle network of cargo-induced conformational changes in PEX5 being involved in the import process. Biochemical studies have also indicated an interdependence of receptor-cargo import with release of unloaded receptor from the peroxisome. Here, we provide an update on recent literature concerning mechanisms of protein import into peroxisomes. © 2016 The Author(s).

Lamb wave propagation in a restricted geometry composite pi-joint specimen

NASA Astrophysics Data System (ADS)

Blackshire, James L.; Soni, Som

2012-05-01

The propagation of elastic waves in a material can involve a number of complex physical phenomena, resulting in both subtle and dramatic effects on detected signal content. In recent years, the use of advanced methods for characterizing and imaging elastic wave propagation and scattering processes has increased, where for example the use of scanning laser vibrometry and advanced computational models have been used very effectively to identify propagating modes, scattering phenomena, and damage feature interactions. In the present effort, the propagation of Lamb waves within a narrow, constrained geometry composite pi-joint structure are studied using 3D finite element models and scanning laser vibrometry measurements, where the effects of varying sample thickness, complex joint curvatures, and restricted structure geometries are highlighted, and a direct comparison of computational and experimental results are provided for simulated and realistic geometry composite pi-joint samples.

Facilitating the exploitation of ERTS imagery using snow enhancement techniques

NASA Technical Reports Server (NTRS)

Wobber, F. J. (Principal Investigator); Martin, K. R.; Amato, R. V.

1973-01-01

The author has identified the following significant results. New fracture detail within New England test area has been interpreted from ERTS-1 images. Comparative analysis of snow-free imagery (1096-15065 and 1096-15072) has demonstrated that MSS bands 5 and 7 supply the greatest amount of geological fracture detail. Interpretation of the first snow-covered ERTS-1 images (1132-15074 and 1168-15065) in correlation with ground snow depth data indicates that a heavy blanket of snow (less than 9 inches) accentuates major structural features while a light dusting (greater than 1 inch) accentuates more subtle topographic expressions. Snow cover was found to accentuate drainage patterns which are indicative of lithological and/or structural variations. Snow cover provided added enhancement for viewing and detecting topographically expressed fractures and faults. A recent field investigation was conducted within the New England test area to field check lineaments observed from analysis of ERTS-1 imagery, collect snow depth readings, and obtain structural joint readings at key locations in the test area.

[The application of wavelet analysis of remote detection of pollution clouds].

PubMed

Zhang, J; Jiang, F

2001-08-01

The discrete wavelet transform (DWT) is used to analyse the spectra of pollution clouds in complicated environment and extract the small-features. The DWT is a time-frequency analysis technology, which detects the subtle small changes in the target spectrum. The results show that the DWT is a quite effective method to extract features of target-cloud and improve the reliability of monitoring alarm system.

Neural representations of emotion are organized around abstract event features.

PubMed

Skerry, Amy E; Saxe, Rebecca

2015-08-03

Research on emotion attribution has tended to focus on the perception of overt expressions of at most five or six basic emotions. However, our ability to identify others' emotional states is not limited to perception of these canonical expressions. Instead, we make fine-grained inferences about what others feel based on the situations they encounter, relying on knowledge of the eliciting conditions for different emotions. In the present research, we provide convergent behavioral and neural evidence concerning the representations underlying these concepts. First, we find that patterns of activity in mentalizing regions contain information about subtle emotional distinctions conveyed through verbal descriptions of eliciting situations. Second, we identify a space of abstract situation features that well captures the emotion discriminations subjects make behaviorally and show that this feature space outperforms competing models in capturing the similarity space of neural patterns in these regions. Together, the data suggest that our knowledge of others' emotions is abstract and high dimensional, that brain regions selective for mental state reasoning support relatively subtle distinctions between emotion concepts, and that the neural representations in these regions are not reducible to more primitive affective dimensions such as valence and arousal. Copyright © 2015 Elsevier Ltd. All rights reserved.

An Energy-Based Approach for Detection and Characterization of Subtle Entities Within Laser Scanning Point-Clouds

NASA Astrophysics Data System (ADS)

Arav, Reuma; Filin, Sagi

2016-06-01

Airborne laser scans present an optimal tool to describe geomorphological features in natural environments. However, a challenge arises in the detection of such phenomena, as they are embedded in the topography, tend to blend into their surroundings and leave only a subtle signature within the data. Most object-recognition studies address mainly urban environments and follow a general pipeline where the data are partitioned into segments with uniform properties. These approaches are restricted to man-made domain and are capable to handle limited features that answer a well-defined geometric form. As natural environments present a more complex set of features, the common interpretation of the data is still manual at large. In this paper, we propose a data-aware detection scheme, unbound to specific domains or shapes. We define the recognition question as an energy optimization problem, solved by variational means. Our approach, based on the level-set method, characterizes geometrically local surfaces within the data, and uses these characteristics as potential field for minimization. The main advantage here is that it allows topological changes of the evolving curves, such as merging and breaking. We demonstrate the proposed methodology on the detection of collapse sinkholes.

Neural Representations of Emotion Are Organized around Abstract Event Features

PubMed Central

Skerry, Amy E.; Saxe, Rebecca

2016-01-01

Summary Research on emotion attribution has tended to focus on the perception of overt expressions of at most five or six basic emotions. However, our ability to identify others' emotional states is not limited to perception of these canonical expressions. Instead, we make fine-grained inferences about what others feel based on the situations they encounter, relying on knowledge of the eliciting conditions for different emotions. In the present research, we provide convergent behavioral and neural evidence concerning the representations underlying these concepts. First, we find that patterns of activity in mentalizing regions contain information about subtle emotional distinctions conveyed through verbal descriptions of eliciting situations. Second, we identify a space of abstract situation features that well captures the emotion discriminations subjects make behaviorally and show that this feature space outperforms competing models in capturing the similarity space of neural patterns in these regions. Together, the data suggest that our knowledge of others' emotions is abstract and high dimensional, that brain regions selective for mental state reasoning support relatively subtle distinctions between emotion concepts, and that the neural representations in these regions are not reducible to more primitive affective dimensions such as valence and arousal. PMID:26212878

X-ray Structural and Biological Evaluation of a Series of Potent and Highly Selective Inhibitors of Human Coronavirus Papain-like Proteases

PubMed Central

2015-01-01

Structure-guided design was used to generate a series of noncovalent inhibitors with nanomolar potency against the papain-like protease (PLpro) from the SARS coronavirus (CoV). A number of inhibitors exhibit antiviral activity against SARS-CoV infected Vero E6 cells and broadened specificity toward the homologous PLP2 enzyme from the human coronavirus NL63. Selectivity and cytotoxicity studies established a more than 100-fold preference for the coronaviral enzyme over homologous human deubiquitinating enzymes (DUBs), and no significant cytotoxicity in Vero E6 and HEK293 cell lines is observed. X-ray structural analyses of inhibitor-bound crystal structures revealed subtle differences between binding modes of the initial benzodioxolane lead (15g) and the most potent analogues 3k and 3j, featuring a monofluoro substitution at para and meta positions of the benzyl ring, respectively. Finally, the less lipophilic bis(amide) 3e and methoxypyridine 5c exhibit significantly improved metabolic stability and are viable candidates for advancing to in vivo studies. PMID:24568342

Population Distribution Analyses Reveal a Hierarchy of Molecular Players Underlying Parallel Endocytic Pathways

PubMed Central

Gupta, Gagan D.; Howes, Mark T.; Chandran, Ruma; Das, Anupam; Menon, Sindhu; Parton, Robert G.; Sowdhamini, R.; Thattai, Mukund; Mayor, Satyajit

2014-01-01

Single-cell-resolved measurements reveal heterogeneous distributions of clathrin-dependent (CD) and -independent (CLIC/GEEC: CG) endocytic activity in Drosophila cell populations. dsRNA-mediated knockdown of core versus peripheral endocytic machinery induces strong changes in the mean, or subtle changes in the shapes of these distributions, respectively. By quantifying these subtle shape changes for 27 single-cell features which report on endocytic activity and cell morphology, we organize 1072 Drosophila genes into a tree-like hierarchy. We find that tree nodes contain gene sets enriched in functional classes and protein complexes, providing a portrait of core and peripheral control of CD and CG endocytosis. For 470 genes we obtain additional features from separate assays and classify them into early- or late-acting genes of the endocytic pathways. Detailed analyses of specific genes at intermediate levels of the tree suggest that Vacuolar ATPase and lysosomal genes involved in vacuolar biogenesis play an evolutionarily conserved role in CG endocytosis. PMID:24971745

Stromatolitic structures associated with sulfur-bearing limestones from the Miocene (Badenian) of the Carpathian Foredeep (S Poland)

NASA Astrophysics Data System (ADS)

Siewicz, Andrzej Gä; Olchowy, Piotr

2010-05-01

The Middle Badenian (Miocene) evaporitic unit is widespread in the Miocene of the Carpathian Foredeep (South Poland). The unit is predominated by sulfates (gypsum + anhydrite) and locally in the northern marginal part of the foredeep contains carbonate complexes up to 45 m thick. The carbonate series are lithologically heterogenous and change from clayey and marl interlayers through marly to pure limestones and may be either sulfur-bearing or barren limestones locally intercalated by sulfate beds and layers. The bulk of the limestones consist of more or less calcareous, either non-bedded or bedded, laminated or streaky mudstones. The series is locally intercalated by breccia, rudstone (nodular) and gypsum-ghost facies. A characteristic feature of the carbonate mudstones lithofacies is the presence of variously developed sparse, thin and finely laminated layers and small (up to few centimeters in height) domal forms clearly resembling stromatolitic structures. The laminated layers usually are up to about 20 cm, discontinuous (up to a few tens meters long) and occur in various stratigraphic positions. The structures reveal wavy or flat, thin and subtle lamination consisting of intercalation of discontinuous native sulfur and calcareous laminae. They are lacking of gypsum selenite relics. There are two kinds of laminae: 1) thicker ones composed of finer to coarser crystalline calcite, sometimes with various clay admixtures and 2) thinner, commonly more or less discontinuous composed of subtle, fine crystalline and pure native sulfur. The calcite laminae are commonly barren with microfossils. The native sulfur laminae are commonly re-crystallized but often contain honey-comb like structures and local pockets with variously preserved sulfur microbial remains. The microfossils are poorly preserved and include coccoid and filamentous remains. The microbial structures are locally associated with irregular patches of structureless amorphous material resembling mucilage associated with many recent microorganisms. The calcite laminae are characterized by variable 18O values ranging in between -3.3 and -6.8‰ PDB and 13C ones from -31.7 to -57.2‰ PDB. The native sulfur forming laminae has positive 34S values changing from 4.6 to 17.2‰ CDT. Both the structural and isotopic data allow to interpret the stromatolitic structures as a result of microbial activity of syntropic sulfate-reducing and methanotrophic consortia + sulfide oxidizing bacteria. As it may be inferred from sedimentological and geochemical features of both the sulfur stromatolitic structures and associated sulfur-bearing limestones, the environment was generally shallow water, penesaline and euxinic, interrupted by meteoric influxes with precipitation of calcite and native sulfur, supply of both detrital and produced in situ organic matter. Such laminated structures have commonly been believed as a lithological equivalent of stromatolitic gypsum beds preserved due to massive replacement of solid gypsum by limestones and limestones + native sulfur. However, a more detailed comparison of geometry and distribution, sedimentological and petrologic features, as well as geochemical signatures accordingly exclude the native sulfur stromatolites as an analogue of the stromatolitic gypsum selenites. It argues against epigenetic replacement of solid sulfates and for syndepositional origin sulfur-bearing limestones.

Subtle imitation behaviour in convenience samples of normal, demented, and currently depressed elderly subjects.

PubMed

von Gunten, Armin; Duc, René

2007-06-01

The clinical significance of imitation behaviour (IB) is unclear. The aim of this study was to investigate the prevalence of subtle naïve and obstinate IB in convenience samples of normal elderly, demented, and depressed subjects. Subtle IB was assessed using a protocol constructed ad hoc in 146 patients, consecutively referred to a memory clinic having received an ICD-10 diagnosis of either dementia or depression, and in 241 healthy subjects. The prevalence of IB in the three groups was determined and the association with possible demographic, cognitive, and non-cognitive variables analysed. Subtle naïve IB was frequent in the elderly with dementia, intermediate in the depressed, and rare in the normal elderly except that the latter frequently stretched out their arms. Obstinate IB never occurred in the normal elderly. IB was predicted by none of the variables used. The groups included were convenience samples with the depressed being a small group precluding further distinction of depressive subtypes. Although naïve IB is a frequent clinical feature in the demented, it also accompanies depressive disorders in the elderly. It can be observed as context-specific IB in the normal elderly. Obstinate IB does not occur in the normal elderly. Copyright 2006 John Wiley & Sons, Ltd.

Neuropsychological Features of Dyslexia.

ERIC Educational Resources Information Center

Feifer, Steven G.

This literature review provides support for the idea that subtle anatomical and functional deviations in the brain correlate with specific types of reading disorders. It finds evidence that symmetry or reversed asymmetry in the plana temporale may be associated with difficulty in acquiring sound/symbol relationships. Studies are reported to show…

Developmental Regression in Autism Spectrum Disorders

ERIC Educational Resources Information Center

Rogers, Sally J.

2004-01-01

The occurrence of developmental regression in autism is one of the more puzzling features of this disorder. Although several studies have documented the validity of parental reports of regression using home videos, accumulating data suggest that most children who demonstrate regression also demonstrated previous, subtle, developmental differences.…

Stratified Mucin-Producing Intraepithelial Lesion of the Cervix: Subtle Features Not to Be Missed.

PubMed

Schwock, Joerg; Ko, Hyang Mi; Dubé, Valérie; Rouzbahman, Marjan; Cesari, Matthew; Ghorab, Zeina; Geddie, William R

2016-01-01

Stratified mucin-producing intraepithelial lesion (SMILE) is an uncommon premalignant lesion of the uterine cervix. A detailed examination of preinvasive SMILE cases including a comparison of the cytologic features with usual-type adenocarcinoma in situ (AIS) and human papillomavirus (HPV) genotyping was performed. Excisions and preceding Papanicolaou (Pap) tests were retrieved from the files of 2 tertiary care centers. Histologic review estimated the lesional SMILE proportion. Pap tests were reviewed and assessed for architectural, cellular and background features. Cobas® HPV test was performed. 13 cases were identified. Mean/median patient age was 35/33 years (range 23-51 years). Concurrent high-grade squamous intraepithelial lesion was found in 10/13 (77%) and AIS in 8/13 (62%) cases. In 6 cases, SMILE was dominant (≥50%) and represented in 5/6 corresponding Pap tests. Cytology interpretations differed more often in the SMILE-dominant group (p < 0.05). SMILE and AIS had overlapping features. Feathering and prominent nucleoli were absent in SMILE. HPV DNA was detected in all 12 cases tested. HPV 18 was most common (7/12). Excisions with positive/suspicious margins were reported in 5/6 SMILE-dominant versus 3/7 nondominant cases. SMILE is best considered as an AIS variant for cytologic, etiologic and management purposes. Cytologic features overlap with AIS, but are more subtle and easily missed. HPV testing may play a role in facilitating SMILE detection. © 2016 S. Karger AG, Basel.

Loss of integrity and atrophy in cingulate structural covariance networks in Parkinson's disease.

PubMed

de Schipper, Laura J; van der Grond, Jeroen; Marinus, Johan; Henselmans, Johanna M L; van Hilten, Jacobus J

2017-01-01

In Parkinson's disease (PD), the relation between cortical brain atrophy on MRI and clinical progression is not straightforward. Determination of changes in structural covariance networks - patterns of covariance in grey matter density - has shown to be a valuable technique to detect subtle grey matter variations. We evaluated how structural network integrity in PD is related to clinical data. 3 Tesla MRI was performed in 159 PD patients. We used nine standardized structural covariance networks identified in 370 healthy subjects as a template in the analysis of the PD data. Clinical assessment comprised motor features (Movement Disorder Society-Unified Parkinson's Disease Rating Scale; MDS-UPDRS motor scale) and predominantly non-dopaminergic features (SEverity of Non-dopaminergic Symptoms in Parkinson's Disease; SENS-PD scale: postural instability and gait difficulty, psychotic symptoms, excessive daytime sleepiness, autonomic dysfunction, cognitive impairment and depressive symptoms). Voxel-based analyses were performed within networks significantly associated with PD. The anterior and posterior cingulate network showed decreased integrity, associated with the SENS-PD score, p = 0.001 (β = - 0.265, η p 2  = 0.070) and p = 0.001 (β = - 0.264, η p 2  = 0.074), respectively. Of the components of the SENS-PD score, cognitive impairment and excessive daytime sleepiness were associated with atrophy within both networks. We identified loss of integrity and atrophy in the anterior and posterior cingulate networks in PD patients. Abnormalities of both networks were associated with predominantly non-dopaminergic features, specifically cognition and excessive daytime sleepiness. Our findings suggest that (components of) the cingulate networks display a specific vulnerability to the pathobiology of PD and may operate as interfaces between networks involved in cognition and alertness.

MindDigger: Feature Identification and Opinion Association for Chinese Movie Reviews

NASA Astrophysics Data System (ADS)

Zhao, Lili; Li, Chunping

In this paper, we present a prototype system called MindDigger, which can be used to analyze the opinions in Chinese movie reviews. Different from previous research that employed techniques on product reviews, we focus on Chinese movie reviews, in which opinions are expressed in subtle and varied ways. The system designed in this work aims to extract the opinion expressions and assign them to the corresponding features. The core tasks include feature and opinion extraction, and feature-opinion association. To deal with Chinese effectively, several novel approaches based on syntactic analysis are proposed in this paper. Running results show the performance is satisfactory.

Automated quantification of surface water inundation in wetlands using optical satellite imagery

USGS Publications Warehouse

DeVries, Ben; Huang, Chengquan; Lang, Megan W.; Jones, John W.; Huang, Wenli; Creed, Irena F.; Carroll, Mark L.

2017-01-01

We present a fully automated and scalable algorithm for quantifying surface water inundation in wetlands. Requiring no external training data, our algorithm estimates sub-pixel water fraction (SWF) over large areas and long time periods using Landsat data. We tested our SWF algorithm over three wetland sites across North America, including the Prairie Pothole Region, the Delmarva Peninsula and the Everglades, representing a gradient of inundation and vegetation conditions. We estimated SWF at 30-m resolution with accuracies ranging from a normalized root-mean-square-error of 0.11 to 0.19 when compared with various high-resolution ground and airborne datasets. SWF estimates were more sensitive to subtle inundated features compared to previously published surface water datasets, accurately depicting water bodies, large heterogeneously inundated surfaces, narrow water courses and canopy-covered water features. Despite this enhanced sensitivity, several sources of errors affected SWF estimates, including emergent or floating vegetation and forest canopies, shadows from topographic features, urban structures and unmasked clouds. The automated algorithm described in this article allows for the production of high temporal resolution wetland inundation data products to support a broad range of applications.

A fast button surface defects detection method based on convolutional neural network

NASA Astrophysics Data System (ADS)

Liu, Lizhe; Cao, Danhua; Wu, Songlin; Wu, Yubin; Wei, Taoran

2018-01-01

Considering the complexity of the button surface texture and the variety of buttons and defects, we propose a fast visual method for button surface defect detection, based on convolutional neural network (CNN). CNN has the ability to extract the essential features by training, avoiding designing complex feature operators adapted to different kinds of buttons, textures and defects. Firstly, we obtain the normalized button region and then use HOG-SVM method to identify the front and back side of the button. Finally, a convolutional neural network is developed to recognize the defects. Aiming at detecting the subtle defects, we propose a network structure with multiple feature channels input. To deal with the defects of different scales, we take a strategy of multi-scale image block detection. The experimental results show that our method is valid for a variety of buttons and able to recognize all kinds of defects that have occurred, including dent, crack, stain, hole, wrong paint and uneven. The detection rate exceeds 96%, which is much better than traditional methods based on SVM and methods based on template match. Our method can reach the speed of 5 fps on DSP based smart camera with 600 MHz frequency.

Fake/Bogus Conferences: Their Features and Some Subtle Ways to Differentiate Them from Real Ones.

PubMed

Asadi, Amin; Rahbar, Nader; Rezvani, Mohammad Javad; Asadi, Fahime

2018-04-01

The main objective of the present paper is to introduce some features of fake/bogus conferences and some viable approaches to differentiate them from the real ones. These fake/bogus conferences introduce themselves as international conferences, which are multidisciplinary and indexed in major scientific digital libraries. Furthermore, most of the fake/bogus conference holders offer publishing the accepted papers in ISI journals and use other techniques in their advertisement e-mails.

Electron crystallography reveals that substrate release from the PTS IIC glucose transporter is coupled to a subtle conformational change.

PubMed

Kalbermatter, David; Chiu, Po-Lin; Jeckelmann, Jean-Marc; Ucurum, Zöhre; Walz, Thomas; Fotiadis, Dimitrios

2017-07-01

The phosphoenolpyruvate-dependent sugar phosphotransferase system (PTS) is a structurally and functionally complex system that mediates sugar uptake in bacteria. Besides several soluble subunits, the glucose-specific PTS includes the integral membrane protein IICB that couples the transmembrane transport of glucose to its phosphorylation. Here, we used electron crystallography of sugar-embedded tubular crystals of the glucose-specific IIC transport domain from Escherichia coli (ecIIC glc ) to visualize the structure of the transporter in the presence and absence of its substrate. Using an in vivo transport assay and binding competition experiments, we first established that, while it transports d-glucose, ecIIC glc does not bind l-glucose. We then determined the projection structure of ecIIC glc from tubular crystals embedded in d- and l-glucose and found a subtle conformational change. From comparison of the ecIIC glc projection maps with crystal structures of other IIC transporters, we can deduce that the transporter adopts an inward-facing conformation, and that the maps in the presence and absence of the substrate reflect the transporter before and after release of the transported glucose into the cytoplasm. The transition associated with substrate release appears to require a subtle structural rearrangement in the region that includes hairpin 1. Copyright © 2017 Elsevier Inc. All rights reserved.

Frustration in biomolecules.

PubMed

Ferreiro, Diego U; Komives, Elizabeth A; Wolynes, Peter G

2014-11-01

Biomolecules are the prime information processing elements of living matter. Most of these inanimate systems are polymers that compute their own structures and dynamics using as input seemingly random character strings of their sequence, following which they coalesce and perform integrated cellular functions. In large computational systems with finite interaction-codes, the appearance of conflicting goals is inevitable. Simple conflicting forces can lead to quite complex structures and behaviors, leading to the concept of frustration in condensed matter. We present here some basic ideas about frustration in biomolecules and how the frustration concept leads to a better appreciation of many aspects of the architecture of biomolecules, and especially how biomolecular structure connects to function by means of localized frustration. These ideas are simultaneously both seductively simple and perilously subtle to grasp completely. The energy landscape theory of protein folding provides a framework for quantifying frustration in large systems and has been implemented at many levels of description. We first review the notion of frustration from the areas of abstract logic and its uses in simple condensed matter systems. We discuss then how the frustration concept applies specifically to heteropolymers, testing folding landscape theory in computer simulations of protein models and in experimentally accessible systems. Studying the aspects of frustration averaged over many proteins provides ways to infer energy functions useful for reliable structure prediction. We discuss how frustration affects folding mechanisms. We review here how the biological functions of proteins are related to subtle local physical frustration effects and how frustration influences the appearance of metastable states, the nature of binding processes, catalysis and allosteric transitions. In this review, we also emphasize that frustration, far from being always a bad thing, is an essential feature of biomolecules that allows dynamics to be harnessed for function. In this way, we hope to illustrate how Frustration is a fundamental concept in molecular biology.

Whittle Communications and Channel One: Rhetorical Strategies of Innovation.

ERIC Educational Resources Information Center

Adams, Scott

A study examined the message features that influence an innovation's acceptance by a mass audience. The study looked at three strategies of innovational rhetoric (denial of controversy, subtle criticism of existing institutions, and projection of a rhetorical vision) used by a commercial broadcasting company, called Whittle Communications in 1989,…

Managing Students' Learning in Classrooms: Reframing Classroom Research.

ERIC Educational Resources Information Center

Fawns, Rod; Salder, Jo

1996-01-01

Analyzes Australian students' public and private statements to themselves and their peers collected in the course of a multiyear study of teacher management of communication in cooperative learning groups. Data reflect how students perceived and responded to subtle features in the public enactment of the curriculum, the task, and the setting…

Coupling of active motion and advection shapes intracellular cargo transport.

PubMed

Khuc Trong, Philipp; Guck, Jochen; Goldstein, Raymond E

2012-07-13

Intracellular cargo transport can arise from passive diffusion, active motor-driven transport along cytoskeletal filament networks, and passive advection by fluid flows entrained by such cargo-motor motion. Active and advective transport are thus intrinsically coupled as related, yet different representations of the same underlying network structure. A reaction-advection-diffusion system is used here to show that this coupling affects the transport and localization of a passive tracer in a confined geometry. For sufficiently low diffusion, cargo localization to a target zone is optimized either by low reaction kinetics and decoupling of bound and unbound states, or by a mostly disordered cytoskeletal network with only weak directional bias. These generic results may help to rationalize subtle features of cytoskeletal networks, for example as observed for microtubules in fly oocytes.

Convolved substructure: analytically decorrelating jet substructure observables

NASA Astrophysics Data System (ADS)

Moult, Ian; Nachman, Benjamin; Neill, Duff

2018-05-01

A number of recent applications of jet substructure, in particular searches for light new particles, require substructure observables that are decorrelated with the jet mass. In this paper we introduce the Convolved SubStructure (CSS) approach, which uses a theoretical understanding of the observable to decorrelate the complete shape of its distribution. This decorrelation is performed by convolution with a shape function whose parameters and mass dependence are derived analytically. We consider in detail the case of the D 2 observable and perform an illustrative case study using a search for a light hadronically decaying Z'. We find that the CSS approach completely decorrelates the D 2 observable over a wide range of masses. Our approach highlights the importance of improving the theoretical understanding of jet substructure observables to exploit increasingly subtle features for performance.

Factors in life science textbooks that may deter girls' interest in science

NASA Astrophysics Data System (ADS)

Potter, Ellen F.; Rosser, Sue V.

In order to examine factors that may deter girls' interest in science, five seventh-grade life science textbooks were analyzed for sexism in language, images, and curricular content, and for features of activities that have been found to be useful for motivating girls. Although overt sexism was not apparent, subtle forms of sexism in the selection of language, images, and curricular content were found. Activities had some features useful to girls, but other features were seldom included. Teachers may wish to use differences that were found among texts as one basis for text selection.

Low-temperature and low atmospheric pressure infrared reflectance spectroscopy of Mars soil analog materials

NASA Technical Reports Server (NTRS)

Bishop, Janice L.; Pieters, Carle M.

1995-01-01

Infrared reflectance spectra of carefully selected Mars soil analog materials have been measured under low atmospheric pressures and temperatures. Chemically altered montmorillonites containing ferrihydrite and hydrated ferric sulfate complexes are examined, as well as synthetic ferrihydrate and a palagonitic soil from Haleakala, Maui. Reflectance spectra of these analog materials exhibit subtle visible to near-infrared features, which are indicative of nanophase ferric oxides or oxyhydroxides and are similar to features observed in the spectra of the bright regions of Mars. Infrared reflectance spectra of these analogs include hydration features due to structural OH, bound H2O and adsorbed H2O. The spectal character of these hydration features is highly dependent on the sample environment and on the nature of the H2O/OH in the analogs. The behavior of the hydration features near 1.9 micrometers, 2.2 micrometers, 2.7 micrometers, 3 micrometers, and 6 micrometers are reported here in spetra measured under Marslike atmospheric environment. In spectra of these analogs measured under dry Earth atmospheric conditions the 1.9-micrometer band depth is 8-17%; this band is much stonger under moist conditions. Under Marslike atmospheric conditions the 1.9-micrometer feature is broad and barely discernible (1-3% band depth) in spectra of the ferrihydrite and palagonitic soil samples. In comparable spectra of the ferric sulfate-bearing montmorillonite the 1.9-micrometer feature is also broad, but stronger (6% band depth). In the low atmospheric pressure and temperature spectra of the ferrihydrite-bearing montmorillonite this feature is sharper than the other analogs and relatively stronger (6% band depth). Although the intensity of the 3- micrometer band is weaker in spectra of each of the analogs when measured under Marslike conditions, the 3-micromter band remains a dominant feature and is especially broad in spectra of the ferrihydrite and palagonitic soil. The structural OH features observed in these materials at 2.2-2.3 micrometers and 2.27 micrometers remain largely unaffected by the environmental conditions. A shift in the Christiansen feature towards shorter wavelengths has also been observed with decreasing atmospheric pressure and temperature in the midinfrared spectra of these samples.

Low-temperature and low atmospheric pressure infrared reflectance spectroscopy of Mars soil analog materials

NASA Technical Reports Server (NTRS)

Bishop, Janice L.; Pieters, Carle M.

1995-01-01

Infrared reflectance spectra of carefully selected Mars soil analog materials have been measured under low atmospheric pressures and temperatures. Chemically altered montmorillonites containing ferrihydrite and hydrated ferric sulfate complexes are examined, as well as synthetic ferrihydrite and a palagonitic soil from Haleakala, Maui. Reflectance spectra of these analog materials exhibit subtle visible to near-infrared features, which are indicative of nanophase ferric oxides or oxyhydroxides and are similar to features observed in the spectra of the bright regions of Mars. Infrared reflectance spectra of these analogs include hydration features due to structural OH, bound H2O, and adsorbed H2O. The spectral character of these hydration features is highly dependent on the sample environment and on the nature of the H2O/OH in the analogs. The behavior of the hydration features near 1.9 micron, 2.2 micron, 2.7 micron, 3 micron, and 6 microns are reported here in spectra measured under a Marslike atmospheric environment. In spectra of these analogs measured under dry Earth atmospheric conditions the 1.9-micron band depth is 8-17%; this band is much stronger under moist conditions. Under Marslike atmospheric conditions the 1.9-micron feature is broad and barely discernible (1-3% band depth) in spectra of the ferrihydrite and palagonitic soil samples. In comparable spectra of the ferric sulfate-bearing montmorillonite the 1.9-micron feature is also broad, but stronger (6% band depth). In the low atmospheric pressure and temperature spectra of the ferrihydrite-bearing montmorillonite this feature is sharper than the other analogs and relatively stronger (6% band depth). Although the intensity of the 3-micron band is weaker in spectra of each of the analogs when measured under Marslike conditions, the 3-micron band remains a dominant feature and is especially broad in spectra of the ferrihydrite and palagonitic soil. The structural OH features observed in these materials at 2.2-2.3 micron and 2.75 microns remain largely unaffected by the environmental conditions. A shift in the Christiansen feature towards shorter wavelengths has also been observed with decreasing atmospheric pressure and temperature in the midinfrared spectra of these samples.

Tall Mountain: Enhanced View

NASA Image and Video Library

2015-08-06

Among the highest features seen on Ceres so far is a mountain about 4 miles (6 kilometers) high, which is roughly the elevation of Mount McKinley in Alaska's Denali National Park. This image comes from an animation, shown in PIA19619, generated using data from NASA's Dawn spacecraft. Vertical relief has been exaggerated by a factor of five. Exaggerating the relief helps scientists understand and visualize the topography much more easily, and highlights features that are sometimes subtle. http://photojournal.jpl.nasa.gov/catalog/PIA19618

Fractal interrelationships in field and seismic data. Quarterly report, September 21 - December 31, 1995

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilson, T.H.; Dominic, J.; Halverson, J.

1995-12-31

Under task 1 contour irregularities traced over both study areas in the previous quarter were scanned into the computer and digitized at a 30 meter interval. Patters mapped in both the Granny Creek and Middle Mountain field areas are presented in Figures 1 and 2 respectively. One of the hypotheses of this research project is that contour irregularities must be controlled by a combination of sedimentation features, lithologic variation, and local structure and fracture distribution. The most promising result obtained thus far in this study are those reported under Tasks 4 and 5, seismic analysis. If further tests continue tomore » support the observation that increased fractal dimension reflects the presence of detached structure, the analytical techniques employed here may be of use in the routine evaluation of seismic data to locate subtle traps. The observations may allow one to predict the variation of fractal dimension within a subsurface fracture network based on seismic observation of resolvable structural parameters. Such predictions would provide a working hypothesis, which could be modified within the context of available subsurface data.« less

On the properties of microsolvated molecules in the ground (S0) and excited (S1) states: The anisole-ammonia 1:1 complex

NASA Astrophysics Data System (ADS)

Biczysko, Malgorzata; Piani, Giovanni; Pasquini, Massimiliano; Schiccheri, Nicola; Pietraperzia, Giangaetano; Becucci, Maurizio; Pavone, Michele; Barone, Vincenzo

2007-10-01

State-of-the-art spectroscopic and theoretical methods have been exploited in a joint effort to elucidate the subtle features of the structure and the energetics of the anisole-ammonia 1:1 complex, a prototype of microsolvation processes. Resonance enhanced multiphoton ionization and laser-induced fluorescence spectra are discussed and compared to high-level first-principles theoretical models, based on density functional, many body second order perturbation, and coupled cluster theories. In the most stable nonplanar structure of the complex, the ammonia interacts with the delocalized π electron density of the anisole ring: hydrogen bonding and dispersive forces provide a comparable stabilization energy in the ground state, whereas in the excited state the dispersion term is negligible because of electron density transfer from the oxygen to the aromatic ring. Ground and excited state geometrical parameters deduced from experimental data and computed by quantum mechanical methods are in very good agreement and allow us to unambiguously determine the molecular structure of the anisole-ammonia complex.

Determination of the conformation of 2-hydroxy- and 2-aminobenzoic acid dimers using 13C NMR and density functional theory/natural bond order analysis: the central importance of the carboxylic acid carbon.

PubMed

Burnette, Ronald R; Weinhold, Frank

2006-07-20

The 13C chemical shift for the carboxylic acid carbon provides a powerful diagnostic probe to determine the preferred isomeric dimer structures of benzoic acid derivatives undergoing intra- and intermolecular H-bonding in the gas, solution and crystalline phases. We have employed hybrid density functional calculations and natural bond orbital analysis to elucidate the electronic origins of the observed 13C shieldings and their relationship to isomeric stability. We find that delocalizing interactions from the carbonyl oxygen lone pairs (nO) into vicinal carbon-oxygen and carbon-carbon antibonds (sigmaCO*,sigmaCC*) make critical contributions to the 13C shieldings, and these nO --> sigmaCO*, nO --> sigmaCC* interactions are in turn sensitive to the intramolecular interactions that dictate dimer structure and stability. The carboxyl carbon atom can thus serve as a useful detector of subtle structural and conformational features in this pharmacologically important class of carboxylic acid interactions.

Looking into the future: An inward bias in aesthetic experience driven only by gaze cues.

PubMed

Chen, Yi-Chia; Colombatto, Clara; Scholl, Brian J

2018-07-01

The inward bias is an especially powerful principle of aesthetic experience: In framed images (e.g. photographs), we prefer peripheral figures that face inward (vs. outward). Why does this bias exist? Since agents tend to act in the direction in which they are facing, one intriguing possibility is that the inward bias reflects a preference to view scenes from a perspective that will allow us to witness those predicted future actions. This account has been difficult to test with previous displays, in which facing direction is often confounded with either global shape profiles or the relative locations of salient features (since e.g. someone's face is generally more visually interesting than the back of their head). But here we demonstrate a robust inward bias in aesthetic judgment driven by a cue that is socially powerful but visually subtle: averted gaze. Subjects adjusted the positions of people in images to maximize the images' aesthetic appeal. People with direct gaze were not placed preferentially in particular regions, but people with averted gaze were reliably placed so that they appeared to be looking inward. This demonstrates that the inward bias can arise from visually subtle features, when those features signal how future events may unfold. Copyright © 2018. Published by Elsevier B.V.

Age, Health and Attractiveness Perception of Virtual (Rendered) Human Hair

PubMed Central

Fink, Bernhard; Hufschmidt, Carla; Hirn, Thomas; Will, Susanne; McKelvey, Graham; Lankhof, John

2016-01-01

The social significance of physical appearance and beauty has been documented in many studies. It is known that even subtle manipulations of facial morphology and skin condition can alter people’s perception of a person’s age, health and attractiveness. While the variation in facial morphology and skin condition cues has been studied quite extensively, comparably little is known on the effect of hair on social perception. This has been partly caused by the technical difficulty of creating appropriate stimuli for investigations of people’s response to systematic variation of certain hair characteristics, such as color and style, while keeping other features constant. Here, we present a modeling approach to the investigation of human hair perception using computer-generated, virtual (rendered) human hair. In three experiments, we manipulated hair diameter (Experiment 1), hair density (Experiment 2), and hair style (Experiment 3) of human (female) head hair and studied perceptions of age, health and attractiveness. Our results show that even subtle changes in these features have an impact on hair perception. We discuss our findings with reference to previous studies on condition-dependent quality cues in women that influence human social perception, thereby suggesting that hair is a salient feature of human physical appearance, which contributes to the perception of beauty. PMID:28066276

Functional video-based analysis of 3D cardiac structures generated from human embryonic stem cells.

PubMed

Nitsch, Scarlett; Braun, Florian; Ritter, Sylvia; Scholz, Michael; Schroeder, Insa S

2018-05-01

Human embryonic stem cells (hESCs) differentiated into cardiomyocytes (CM) often develop into complex 3D structures that are composed of various cardiac cell types. Conventional methods to study the electrophysiology of cardiac cells are patch clamp and microelectrode array (MEAs) analyses. However, these methods are not suitable to investigate the contractile features of 3D cardiac clusters that detach from the surface of the culture dishes during differentiation. To overcome this problem, we developed a video-based motion detection software relying on the optical flow by Farnebäck that we call cBRA (cardiac beat rate analyzer). The beating characteristics of the differentiated cardiac clusters were calculated based on the local displacement between two subsequent images. Two differentiation protocols, which profoundly differ in the morphology of cardiac clusters generated and in the expression of cardiac markers, were used and the resulting CM were characterized. Despite these differences, beat rates and beating variabilities could be reliably determined using cBRA. Likewise, stimulation of β-adrenoreceptors by isoproterenol could easily be identified in the hESC-derived CM. Since even subtle changes in the beating features are detectable, this method is suitable for high throughput cardiotoxicity screenings. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

New Insights into the In Silico Prediction of HIV Protease Resistance to Nelfinavir

PubMed Central

Antunes, Dinler A.; Rigo, Maurício M.; Sinigaglia, Marialva; de Medeiros, Rúbia M.; Junqueira, Dennis M.; Almeida, Sabrina E. M.; Vieira, Gustavo F.

2014-01-01

The Human Immunodeficiency Virus type 1 protease enzyme (HIV-1 PR) is one of the most important targets of antiretroviral therapy used in the treatment of AIDS patients. The success of protease-inhibitors (PIs), however, is often limited by the emergence of protease mutations that can confer resistance to a specific drug, or even to multiple PIs. In the present study, we used bioinformatics tools to evaluate the impact of the unusual mutations D30V and V32E over the dynamics of the PR-Nelfinavir complex, considering that codons involved in these mutations were previously related to major drug resistance to Nelfinavir. Both studied mutations presented structural features that indicate resistance to Nelfinavir, each one with a different impact over the interaction with the drug. The D30V mutation triggered a subtle change in the PR structure, which was also observed for the well-known Nelfinavir resistance mutation D30N, while the V32E exchange presented a much more dramatic impact over the PR flap dynamics. Moreover, our in silico approach was also able to describe different binding modes of the drug when bound to different proteases, identifying specific features of HIV-1 subtype B and subtype C proteases. PMID:24498124

RNA-TVcurve: a Web server for RNA secondary structure comparison based on a multi-scale similarity of its triple vector curve representation.

PubMed

Li, Ying; Shi, Xiaohu; Liang, Yanchun; Xie, Juan; Zhang, Yu; Ma, Qin

2017-01-21

RNAs have been found to carry diverse functionalities in nature. Inferring the similarity between two given RNAs is a fundamental step to understand and interpret their functional relationship. The majority of functional RNAs show conserved secondary structures, rather than sequence conservation. Those algorithms relying on sequence-based features usually have limitations in their prediction performance. Hence, integrating RNA structure features is very critical for RNA analysis. Existing algorithms mainly fall into two categories: alignment-based and alignment-free. The alignment-free algorithms of RNA comparison usually have lower time complexity than alignment-based algorithms. An alignment-free RNA comparison algorithm was proposed, in which novel numerical representations RNA-TVcurve (triple vector curve representation) of RNA sequence and corresponding secondary structure features are provided. Then a multi-scale similarity score of two given RNAs was designed based on wavelet decomposition of their numerical representation. In support of RNA mutation and phylogenetic analysis, a web server (RNA-TVcurve) was designed based on this alignment-free RNA comparison algorithm. It provides three functional modules: 1) visualization of numerical representation of RNA secondary structure; 2) detection of single-point mutation based on secondary structure; and 3) comparison of pairwise and multiple RNA secondary structures. The inputs of the web server require RNA primary sequences, while corresponding secondary structures are optional. For the primary sequences alone, the web server can compute the secondary structures using free energy minimization algorithm in terms of RNAfold tool from Vienna RNA package. RNA-TVcurve is the first integrated web server, based on an alignment-free method, to deliver a suite of RNA analysis functions, including visualization, mutation analysis and multiple RNAs structure comparison. The comparison results with two popular RNA comparison tools, RNApdist and RNAdistance, showcased that RNA-TVcurve can efficiently capture subtle relationships among RNAs for mutation detection and non-coding RNA classification. All the relevant results were shown in an intuitive graphical manner, and can be freely downloaded from this server. RNA-TVcurve, along with test examples and detailed documents, are available at: http://ml.jlu.edu.cn/tvcurve/ .

Neurologic and developmental features of the Smith-Magenis syndrome (del 17p11.2).

PubMed

Gropman, Andrea L; Duncan, Wallace C; Smith, Ann C M

2006-05-01

The Smith-Magenis syndrome is a rare, complex multisystemic disorder featuring, mental retardation and multiple congenital anomalies caused by a heterozygous interstitial deletion of chromosome 17p11.2. The phenotype of Smith-Magenis syndrome is characterized by a distinct pattern of features including infantile hypotonia, generalized complacency and lethargy in infancy, minor skeletal (brachycephaly, brachydactyly) and craniofacial features, ocular abnormalities, middle ear and laryngeal abnormalities including hoarse voice, as well as marked early expressive speech and language delays, psychomotor and growth retardation, and a 24-hour sleep disturbance. A striking neurobehavioral pattern of stereotypies, hyperactivity, polyembolokoilamania, onychotillomania, maladaptive and self-injurious and aggressive behavior is observed with increasing age. The diagnosis of Smith-Magenis syndrome is based upon the clinical recognition of a constellation of physical, developmental, and behavioral features in combination with a sleep disorder characterized by inverted circadian rhythm of melatonin secretion. Many of the features of Smith-Magenis syndrome are subtle in infancy and early childhood, and become more recognizable with advancing age. Infants are described as looking "cherubic" with a Down syndrome-like appearance, whereas with age the facial appearance is that of relative prognathism. Early diagnosis requires awareness of the often subtle clinical and neurobehavioral phenotype of the infant period. Speech delay with or without hearing loss is common. Most children are diagnosed in mid-childhood when the features of the disorder are most recognizable and striking. While improvements in cytogenetic analysis help to bring cases to clinical recognition at an earlier age, this review seeks to increase clinical awareness about Smith-Magenis syndrome by presenting the salient features observed at different ages including descriptions of the neurologic and behavioral features. Detailed review of the circadian rhythm disturbance unique to Smith-Magenis syndrome is presented. Suggestions for management of the behavioral and sleep difficulties are discussed in the context of the authors' personal experience in the setting of an ongoing Smith-Magenis syndrome natural history study.

Metaphor and analogy in everyday problem solving.

PubMed

Keefer, Lucas A; Landau, Mark J

2016-11-01

Early accounts of problem solving focused on the ways people represent information directly related to target problems and possible solutions. Subsequent theory and research point to the role of peripheral influences such as heuristics and bodily states. We discuss how metaphor and analogy similarly influence stages of everyday problem solving: Both processes mentally map features of a target problem onto the structure of a relatively more familiar concept. When individuals apply this structure, they use a well-known concept as a framework for reasoning about real world problems and candidate solutions. Early studies found that analogy use helped people gain insight into novel problems. More recent research on metaphor goes further to show that activating mappings has subtle, sometimes surprising effects on judgment and reasoning in everyday problem solving. These findings highlight situations in which mappings can help or hinder efforts to solve problems. WIREs Cogn Sci 2016, 7:394-405. doi: 10.1002/wcs.1407 For further resources related to this article, please visit the WIREs website. © 2016 Wiley Periodicals, Inc.

A greedy-navigator approach to navigable city plans

NASA Astrophysics Data System (ADS)

Lee, Sang Hoon; Holme, Petter

2013-01-01

We use a set of four theoretical navigability indices for street maps to investigate the shape of the resulting street networks, if they are grown by optimizing these indices. The indices compare the performance of simulated navigators (having a partial information about the surroundings, like humans in many real situations) to the performance of optimally navigating individuals. We show that our simple greedy shortcut construction strategy generates the emerging structures that are different from real road network, but not inconceivable. The resulting city plans, for all navigation indices, share common qualitative properties such as the tendency for triangular blocks to appear, while the more quantitative features, such as degree distributions and clustering, are characteristically different depending on the type of metrics and routing strategies. We show that it is the type of metrics used which determines the overall shapes characterized by structural heterogeneity, but the routing schemes contribute to more subtle details of locality, which is more emphasized in case of unrestricted connections when the edge crossing is allowed.

Groupwise shape analysis of the hippocampus using spectral matching

NASA Astrophysics Data System (ADS)

Shakeri, Mahsa; Lombaert, Hervé; Lippé, Sarah; Kadoury, Samuel

2014-03-01

The hippocampus is a prominent subcortical feature of interest in many neuroscience studies. Its subtle morphological changes often predicate illnesses, including Alzheimer's, schizophrenia or epilepsy. The precise location of structural differences requires a reliable correspondence between shapes across a population. In this paper, we propose an automated method for groupwise hippocampal shape analysis based on a spectral decomposition of a group of shapes to solve the correspondence problem between sets of meshes. The framework generates diffeomorphic correspondence maps across a population, which enables us to create a mean shape. Morphological changes are then located between two groups of subjects. The performance of the proposed method was evaluated on a dataset of 42 hippocampus shapes and compared with a state-of-the-art structural shape analysis approach, using spherical harmonics. Difference maps between mean shapes of two test groups demonstrates that the two approaches showed results with insignificant differences, while Gaussian curvature measures calculated between matched vertices showed a better fit and reduced variability with spectral matching.

Release of volatiles from a possible cryovolcano from near-infrared imaging of Titan

USGS Publications Warehouse

Sotin, Christophe; Jaumann, R.; Buratti, B.J.; Brown, R.H.; Clark, R.N.; Soderblom, L.A.; Baines, K.H.; Bellucci, G.; Bibring, J.-P.; Capaccioni, F.; Cerroni, P.; Combes, M.; Coradini, A.; Cruikshank, D.P.; Drossart, P.; Formisano, V.; Langevin, Y.; Matson, D.L.; McCord, T.B.; Nelson, R.M.; Nicholson, P.D.; Sicardy, B.; Lemouelic, S.; Rodriguez, S.; Stephan, K.; Scholz, C.K.

2005-01-01

Titan is the only satellite in our Solar System with a dense atmosphere. The surface pressure is 1.5 bar (ref. 1) and, similar to the Earth, N 2 is the main component of the atmosphere. Methane is the second most important component, but it is photodissociated on a timescale of 10 years (ref. 3). This short timescale has led to the suggestion that Titan may possess a surface or subsurface reservoir of hydrocarbons to replenish the atmosphere. Here we report near-infrared images of Titan obtained on 26 October 2004 by the Cassini spacecraft. The images show that a widespread methane ocean does not exist; subtle albedo variations instead suggest topographical variations, as would be expected for a more solid (perhaps icy) surface. We also find a circular structure ???30 km in diameter that does not resemble any features seen on other icy satellites. We propose that the structure is a dome formed by upwelling icy plumes that release methane into Titan's atmosphere.

Release of volatiles from a possible cryovolcano from near-infrared imaging of Titan.

PubMed

Sotin, C; Jaumann, R; Buratti, B J; Brown, R H; Clark, R N; Soderblom, L A; Baines, K H; Bellucci, G; Bibring, J-P; Capaccioni, F; Cerroni, P; Combes, M; Coradini, A; Cruikshank, D P; Drossart, P; Formisano, V; Langevin, Y; Matson, D L; McCord, T B; Nelson, R M; Nicholson, P D; Sicardy, B; LeMouelic, S; Rodriguez, S; Stephan, K; Scholz, C K

2005-06-09

Titan is the only satellite in our Solar System with a dense atmosphere. The surface pressure is 1.5 bar (ref. 1) and, similar to the Earth, N2 is the main component of the atmosphere. Methane is the second most important component, but it is photodissociated on a timescale of 10(7) years (ref. 3). This short timescale has led to the suggestion that Titan may possess a surface or subsurface reservoir of hydrocarbons to replenish the atmosphere. Here we report near-infrared images of Titan obtained on 26 October 2004 by the Cassini spacecraft. The images show that a widespread methane ocean does not exist; subtle albedo variations instead suggest topographical variations, as would be expected for a more solid (perhaps icy) surface. We also find a circular structure approximately 30 km in diameter that does not resemble any features seen on other icy satellites. We propose that the structure is a dome formed by upwelling icy plumes that release methane into Titan's atmosphere.

Uncovering the true nature of deformation microstructures using 3D analysis methods

NASA Astrophysics Data System (ADS)

Ferry, M.; Quadir, M. Z.; Afrin, N.; Xu, W.; Loeb, A.; Soe, B.; McMahon, C.; George, C.; Bassman, L.

2015-08-01

Three-dimensional electron backscatter diffraction (3D EBSD) has emerged as a powerful technique for generating 3D crystallographic information in reasonably large volumes of a microstructure. The technique uses a focused ion beam (FIB) as a high precision serial sectioning device for generating consecutive ion milled surfaces of a material, with each milled surface subsequently mapped by EBSD. The successive EBSD maps are combined using a suitable post-processing method to generate a crystallographic volume of the microstructure. The first part of this paper shows the usefulness of 3D EBSD for understanding the origin of various structural features associated with the plastic deformation of metals. The second part describes a new method for automatically identifying the various types of low and high angle boundaries found in deformed and annealed metals, particularly those associated with grains exhibiting subtle and gradual variations in orientation. We have adapted a 2D image segmentation technique, fast multiscale clustering, to 3D EBSD data using a novel variance function to accommodate quaternion data. This adaptation is capable of segmenting based on subtle and gradual variation as well as on sharp boundaries within the data. We demonstrate the excellent capabilities of this technique with application to 3D EBSD data sets generated from a range of cold rolled and annealed metals described in the paper.

Optical Coherence Tomography in Glaucoma

NASA Astrophysics Data System (ADS)

Berisha, Fatmire; Hoffmann, Esther M.; Pfeiffer, Norbert

Retinal nerve fiber layer (RNFL) thinning and optic nerve head cupping are key diagnostic features of glaucomatous optic neuropathy. The higher resolution of the recently introduced SD-OCT offers enhanced visualization and improved segmentation of the retinal layers, providing a higher accuracy in identification of subtle changes of the optic disc and RNFL thinning associated with glaucoma.

Prosody Predicts Contest Outcome in Non-Verbal Dialogs

PubMed Central

Dreiss, Amélie N.; Chatelain, Philippe G.

2016-01-01

Non-verbal communication has important implications for inter-individual relationships and negotiation success. However, to what extent humans can spontaneously use rhythm and prosody as a sole communication tool is largely unknown. We analysed human ability to resolve a conflict without verbal dialogs, independently of semantics. We invited pairs of subjects to communicate non-verbally using whistle sounds. Along with the production of more whistles, participants unwittingly used a subtle prosodic feature to compete over a resource (ice-cream scoops). Winners can be identified by their propensity to accentuate the first whistles blown when replying to their partner, compared to the following whistles. Naive listeners correctly identified this prosodic feature as a key determinant of which whistler won the interaction. These results suggest that in the absence of other communication channels, individuals spontaneously use a subtle variation of sound accentuation (prosody), instead of merely producing exuberant sounds, to impose themselves in a conflict of interest. We discuss the biological and cultural bases of this ability and their link with verbal communication. Our results highlight the human ability to use non-verbal communication in a negotiation process. PMID:27907039

Prosody Predicts Contest Outcome in Non-Verbal Dialogs.

PubMed

Dreiss, Amélie N; Chatelain, Philippe G; Roulin, Alexandre; Richner, Heinz

2016-01-01

Non-verbal communication has important implications for inter-individual relationships and negotiation success. However, to what extent humans can spontaneously use rhythm and prosody as a sole communication tool is largely unknown. We analysed human ability to resolve a conflict without verbal dialogs, independently of semantics. We invited pairs of subjects to communicate non-verbally using whistle sounds. Along with the production of more whistles, participants unwittingly used a subtle prosodic feature to compete over a resource (ice-cream scoops). Winners can be identified by their propensity to accentuate the first whistles blown when replying to their partner, compared to the following whistles. Naive listeners correctly identified this prosodic feature as a key determinant of which whistler won the interaction. These results suggest that in the absence of other communication channels, individuals spontaneously use a subtle variation of sound accentuation (prosody), instead of merely producing exuberant sounds, to impose themselves in a conflict of interest. We discuss the biological and cultural bases of this ability and their link with verbal communication. Our results highlight the human ability to use non-verbal communication in a negotiation process.

HiCRep: assessing the reproducibility of Hi-C data using a stratum-adjusted correlation coefficient

PubMed Central

Yang, Tao; Zhang, Feipeng; Yardımcı, Galip Gürkan; Song, Fan; Hardison, Ross C.; Noble, William Stafford; Yue, Feng; Li, Qunhua

2017-01-01

Hi-C is a powerful technology for studying genome-wide chromatin interactions. However, current methods for assessing Hi-C data reproducibility can produce misleading results because they ignore spatial features in Hi-C data, such as domain structure and distance dependence. We present HiCRep, a framework for assessing the reproducibility of Hi-C data that systematically accounts for these features. In particular, we introduce a novel similarity measure, the stratum adjusted correlation coefficient (SCC), for quantifying the similarity between Hi-C interaction matrices. Not only does it provide a statistically sound and reliable evaluation of reproducibility, SCC can also be used to quantify differences between Hi-C contact matrices and to determine the optimal sequencing depth for a desired resolution. The measure consistently shows higher accuracy than existing approaches in distinguishing subtle differences in reproducibility and depicting interrelationships of cell lineages. The proposed measure is straightforward to interpret and easy to compute, making it well-suited for providing standardized, interpretable, automatable, and scalable quality control. The freely available R package HiCRep implements our approach. PMID:28855260

Origin and development of plains-type folds in the mid-continent (United States) during the late Paleozoic

USGS Publications Warehouse

Merriam, D.F.

2005-01-01

Plains-type folds are local, subtle anticlines formed in the thin sedimentary package overlying a shallow, crystalline basement on the craton. They are small in areal extent (usually less than 1-3 km 2 [0.4-1.2 mi2]), and their amplitude increases with depth (usually tens of meters), which is mainly the result of differential compaction of sediments (usually clastic units) over tilted, rigid, basement fault blocks. The development of these structural features by continuous but intermittent movement of the basement fault blocks in the late Paleozoic in the United States mid-continent is substantiated by a record of stratigraphic and sedimentological evidence. The recurrent structural movement, which reflects adjustment to external stresses, is expressed by the change in thickness of stratigraphic units over the crest of the fold compared to the flanks. By plotting the change in thickness for different stratigraphic units of anticlines on different fault blocks, it is possible to determine the timing of movement of the blocks that reflect structural adjustment. These readjustments are confirmed by sedimentological evidence, such as convolute, soft-sediment deformation features and small intraformational faults. The stratigraphic interval change in thickness for numerous structures in the Cherokee, Forest City, and Salina basins and on the Nemaha anticline of the mid-continent United States was determined and compared for location and timing of the adjustments. Most of the adjustment occurred during and after time of deposition of the Permian-Pennsylvanian clastic units, which, in turn, reflect tectonic disturbance in adjacent areas, and the largest amount of movement on the plains-type structures occurred on those nearest and semiparallel to major positive features, such as the Nemaha anticline. Depending on the time of origin and development of plains-type folds, they may control the entrapment and occurrence of oil and gas. Copyright ??2005. The American Association of Petroleum Geologists. All rights reserved.

Multi-centre diagnostic classification of individual structural neuroimaging scans from patients with major depressive disorder.

PubMed

Mwangi, Benson; Ebmeier, Klaus P; Matthews, Keith; Steele, J Douglas

2012-05-01

Quantitative abnormalities of brain structure in patients with major depressive disorder have been reported at a group level for decades. However, these structural differences appear subtle in comparison with conventional radiologically defined abnormalities, with considerable inter-subject variability. Consequently, it has not been possible to readily identify scans from patients with major depressive disorder at an individual level. Recently, machine learning techniques such as relevance vector machines and support vector machines have been applied to predictive classification of individual scans with variable success. Here we describe a novel hybrid method, which combines machine learning with feature selection and characterization, with the latter aimed at maximizing the accuracy of machine learning prediction. The method was tested using a multi-centre dataset of T(1)-weighted 'structural' scans. A total of 62 patients with major depressive disorder and matched controls were recruited from referred secondary care clinical populations in Aberdeen and Edinburgh, UK. The generalization ability and predictive accuracy of the classifiers was tested using data left out of the training process. High prediction accuracy was achieved (~90%). While feature selection was important for maximizing high predictive accuracy with machine learning, feature characterization contributed only a modest improvement to relevance vector machine-based prediction (~5%). Notably, while the only information provided for training the classifiers was T(1)-weighted scans plus a categorical label (major depressive disorder versus controls), both relevance vector machine and support vector machine 'weighting factors' (used for making predictions) correlated strongly with subjective ratings of illness severity. These results indicate that machine learning techniques have the potential to inform clinical practice and research, as they can make accurate predictions about brain scan data from individual subjects. Furthermore, machine learning weighting factors may reflect an objective biomarker of major depressive disorder illness severity, based on abnormalities of brain structure.

Exploring glycogen biosynthesis through Monte Carlo simulation.

PubMed

Zhang, Peng; Nada, Sharif S; Tan, Xinle; Deng, Bin; Sullivan, Mitchell A; Gilbert, Robert G

2018-05-08

Glycogen, a complex branched polymer of glucose (average chain length ~10 monomer units), is the blood-sugar reservoir in humans and other animals. Certain aspects of its molecular structure relevant to its biological functions are currently unamenable to experimental exploration. Knowledge of these is needed to develop future models for quantitative data-fitting to obtain mechanistic understanding of the biosynthetic processes that give rise to glycogen structure. Monte Carlo simulations of the biosynthesis of this structure with realistic macromolecular parameters reveal how chain growth and stoppage (the latter assumed to be through both the action of glycogen branching enzyme and other degradative enzymes, and by hindrance) control structural features. The simulated chain-length, pair-distance and radial density distributions agree semi-quantitatively with the limited available data. The simulations indicate that a steady state in molecular structure and size is rapidly obtained, that molecular density reaches a maximum near the center of the particle (not at the periphery, as is the case with dendrimers), and that particle size is controlled by both enzyme activity and hindrance. This knowledge will aid in the understanding of diabetes (loss of blood-sugar control), which has been found to involve subtle differences in glycogen molecular structure. Copyright © 2018 Elsevier B.V. All rights reserved.

Learning deep similarity in fundus photography

NASA Astrophysics Data System (ADS)

Chudzik, Piotr; Al-Diri, Bashir; Caliva, Francesco; Ometto, Giovanni; Hunter, Andrew

2017-02-01

Similarity learning is one of the most fundamental tasks in image analysis. The ability to extract similar images in the medical domain as part of content-based image retrieval (CBIR) systems has been researched for many years. The vast majority of methods used in CBIR systems are based on hand-crafted feature descriptors. The approximation of a similarity mapping for medical images is difficult due to the big variety of pixel-level structures of interest. In fundus photography (FP) analysis, a subtle difference in e.g. lesions and vessels shape and size can result in a different diagnosis. In this work, we demonstrated how to learn a similarity function for image patches derived directly from FP image data without the need of manually designed feature descriptors. We used a convolutional neural network (CNN) with a novel architecture adapted for similarity learning to accomplish this task. Furthermore, we explored and studied multiple CNN architectures. We show that our method can approximate the similarity between FP patches more efficiently and accurately than the state-of- the-art feature descriptors, including SIFT and SURF using a publicly available dataset. Finally, we observe that our approach, which is purely data-driven, learns that features such as vessels calibre and orientation are important discriminative factors, which resembles the way how humans reason about similarity. To the best of authors knowledge, this is the first attempt to approximate a visual similarity mapping in FP.

ASSESSING HIPPOCAMPAL CHANGES INDICATIVE OF NEUROTOXIC EFFECTS.

EPA Science Inventory

Subtle changes in cognitive function are often the earliest indication of neurotoxic effects in humans. The hippocampus is a large forebrain structure subserving specific kinds of information encoding and consolidation in humans and other animals. Because of it laminar structur...

Exploration for fractured petroleum reservoirs using radar/Landsat merge combinations

NASA Technical Reports Server (NTRS)

Macdonald, H.; Waite, W.; Borengasser, M.; Tolman, D.; Elachi, C.

1981-01-01

Since fractures are commonly propagated upward and reflected at the earth's surface as subtle linears, detection of these surface features is extremely important in many phases of petroleum exploration and development. To document the usefulness of microwave analysis for petroleum exploration, the Arkansas part of the Arkoma basin is selected as a prime test site. The research plan involves comparing the aircraft microwave imagery and Landsat imagery in an area where significant subsurface borehole geophysical data are available. In the northern Arkoma basin, a positive correlation between the number of linears in a given area and production from cherty carbonate strata is found. In the southern part of the basin, little relationship is discernible between surface structure and gas production, and no correlation is found between gas productivity and linear proximity or linear density as determined from remote sensor data.

SPOT satellite mapping of Ice Stream B

NASA Technical Reports Server (NTRS)

Merry, Carolyn J.

1993-01-01

Numerous features of glaciological significance appear on two adjoining SPOT High Resolution Visible (HRV) images that cover the onset region of ice stream B. Many small-scale features, such as crevasses and drift plumes, have been previously observed in aerial photography. Subtle features, such as long flow traces that have not been mapped previously, are also clear in the satellite imagery. Newly discovered features include ladder-like runners and rungs within certain shear margins, flow traces that are parallel to ice flow, unusual crevasse patterns, and flow traces originating within shear margins. An objective of our work is to contribute to an understanding of the genesis of the features observed in satellite imagery. The genetic possibilities for flow traces, other lineations, bands of transverse crevasses, shear margins, mottles, and lumps and warps are described.

Congenital dysplasias and dwarfism.

PubMed

Clark, R N

1990-11-01

This paper has presented the characteristic features of those types of dwarfism that are manifest at birth. This information has been presented in a fashion that should assist the pediatrician in arriving at an appropriate diagnosis without excessive delay or extensive diagnostic studies. However, variable expressivity may result in subtle presentation and, in those cases, diagnosis may be more challenging.

Black Hole Interior in Quantum Gravity.

PubMed

Nomura, Yasunori; Sanches, Fabio; Weinberg, Sean J

2015-05-22

We discuss the interior of a black hole in quantum gravity, in which black holes form and evaporate unitarily. The interior spacetime appears in the sense of complementarity because of special features revealed by the microscopic degrees of freedom when viewed from a semiclassical standpoint. The relation between quantum mechanics and the equivalence principle is subtle, but they are still consistent.

Social relationship difficulties in autism and reactive attachment disorder: Improving diagnostic validity through structured assessment.

PubMed

Davidson, Claire; O'Hare, Anne; Mactaggart, Fiona; Green, Jonathan; Young, David; Gillberg, Christopher; Minnis, Helen

2015-05-01

Autism Spectrum Disorder (ASD) versus Reactive Attachment Disorder (RAD) is a common diagnostic challenge for clinicians due to overlapping difficulties with social relationships. RAD is associated with neglect or maltreatment whereas ASD is not: accurate differential diagnosis is therefore critical. Very little research has investigated the relationship between the two, and it is unknown if standardised measures are able to discriminate between ASD and RAD. The current study aimed to address these issues. Fifty eight children with ASD, and no history of maltreatment, were group matched on age with 67 children with RAD. Group profiles on multi-informant measures of RAD were investigated and group differences explored. Discriminant function analysis determined assessment features that best discriminated between the two groups. Although, according to parent report, children with ASD presented with significantly fewer indiscriminate friendliness behaviours compared to the RAD group (p<0.001), 36 children with ASD appeared to meet core RAD criteria. However, structured observation clearly demonstrated that features were indicative of ASD and not RAD for all but 1 of these 36 children. Children with RAD and children with ASD may demonstrate similar social relationship difficulties but there appears to be a difference in the social quality of the interactions between the groups. In most cases it was possible to differentiate between children with ASD and children with RAD via structured observation. Nevertheless, for a small proportion of children with ASD, particularly those whose difficulties may be more subtle, our current standardised measures, including structured observation, may not be effective in differentiating RAD from ASD. Copyright © 2015. Published by Elsevier Ltd.

Tuning and Freezing Disorder in Photonic Crystals using Percolation Lithography.

PubMed

Burgess, Ian B; Abedzadeh, Navid; Kay, Theresa M; Shneidman, Anna V; Cranshaw, Derek J; Lončar, Marko; Aizenberg, Joanna

2016-01-21

Although common in biological systems, synthetic self-assembly routes to complex 3D photonic structures with tailored degrees of disorder remain elusive. Here we show how liquids can be used to finely control disorder in porous 3D photonic crystals, leading to complex and hierarchical geometries. In these optofluidic crystals, dynamically tunable disorder is superimposed onto the periodic optical structure through partial wetting or evaporation. In both cases, macroscopic symmetry breaking is driven by subtle sub-wavelength variations in the pore geometry. These variations direct site-selective infiltration of liquids through capillary interactions. Incorporating cross-linkable resins into our liquids, we developed methods to freeze in place the filling patterns at arbitrary degrees of partial wetting and intermediate stages of drying. These percolation lithography techniques produced permanent photonic structures with adjustable disorder. By coupling strong changes in optical properties to subtle differences in fluid behavior, optofluidic crystals may also prove useful in rapid analysis of liquids.

Structural interpretation from horizontal seismic sections

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, A.R.

1983-03-01

The interpreter of a 3D survey must use a data volume. Horizontal slices through a data volume, called Seiscrop sections, have unique properties and structural interpretation from them is fast, convenient, and effective. An event on a Seiscrop section displays local strike, a property which permits direct contouring of a structural surface without any timing and posting. The width of an event on a Seiscrop section is a composition of the frequency of the data and the structural dip. Event terminations indicate faults or other discontinuities when they are transverse to structural strike. Faults parallel to structural strike are muchmore » less evident on a single Seiscrop section but become apparent with the relative movement of events from section to section. In practical mapping, we normally contour one fault block before proceeding to the next with the correlation between them being established from the vertical sections. With dual polarity variable area displays, the interpreter can perceive five amplitude levels and normally picks the edge of a trough. With color amplitude Seiscrop sections, it is possible to pick on the crest of any event. With color phase sections the interpreter can pick at any arbitrary but consistent point on the seismic waveform. Subtle structural features are commonly revealed on horizontal sections which may never have been noticed if working from vertical sections alone.« less

Features and dimensions of the Hayward Fault Zone in the Strawberry and Blackberry Creek Area, Berkeley, California

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, P.L.

1995-03-01

This report presents an examination of the geometry of the Hayward fault adjacent to the Lawrence Berkeley Laboratory and University of California campuses in central Berkeley. The fault crosses inside the eastern border of the UC campus. Most subtle geomorphic (landform) expressions of the fault have been removed by development and by the natural processes of landsliding and erosion. Some clear expressions of the fault remain however, and these are key to mapping the main trace through the campus area. In addition, original geomorphic evidence of the fault`s location was recovered from large scale mapping of the site dating frommore » 1873 to 1897. Before construction obscured and removed natural landforms, the fault was expressed by a linear, northwest-tending zone of fault-related geomorphic features. There existed well-defined and subtle stream offsets and beheaded channels, fault scarps, and a prominent ``shutter ridge``. To improve our confidence in fault locations interpreted from landforms, we referred to clear fault exposures revealed in trenching, revealed during the construction of the Foothill Housing Complex, and revealed along the length of the Lawson Adit mining tunnel. Also utilized were the locations of offset cultural features. At several locations across the study area, distress features in buildings and streets have been used to precisely locate the fault. Recent published mapping of the fault (Lienkaemper, 1992) was principally used for reference to evidence of the fault`s location to the northwest and southeast of Lawrence Berkeley Laboratory.« less

The Influence of Social Cues and Cognitive Processes in Computer Mediated Second Language Learning

ERIC Educational Resources Information Center

Murakami, Janel Rachel Goodman

2017-01-01

This dissertation investigated the effects of technological mediation on second language (L2) learning, focusing, as a case study, on gains in listening perception of the subtle but important feature of pitch placement in Japanese. Pitch accent can be difficult to perceive for non-native speakers whose first language (L1) does not rely on pitch or…

Detection of CN emission from (2060) Chiron

NASA Technical Reports Server (NTRS)

Bowell, Edward

1991-01-01

Spectrophotometric observations of (2060) Chiron were obtained. Their primary goal was to look for the subtle differences in color between Chiron and its surrounding coma, and to search for possible absorption or emission features in Chiron's spectrum. The presence of the CN(0-0) emission band was identified. It proves Chiron's cometary nature and breaks the record heliocentric distance for cometary gaseous emission.

Evolution of certain typical and atypical features in a case of subacute sclerosing panencephalitis

PubMed Central

Raut, Tushar Premraj; Singh, Maneesh Kumar; Garg, Ravindra Kumar; Rai, Dheeraj

2012-01-01

Subacute sclerosing panencephalitis (SSPE) is a slowly progressive inflammatory disease of the central nervous system caused by a persistent measles virus usually affecting the childhood and adolescent age group. Clinical features at onset are very subtle and non-specific. Certain atypical features can occur at onset or during the course of illness which can be misleading. Neuroimaging features often are non-specific. Features like myoclonic jerks, cognitive decline and typical EEG findings lead to a strong suspicion of SSPE. Here, we describe the stagewise progression of a case of SSPE in a 14-year-old girl who had myoclonic jerks and cognitive decline at onset. During the course of disease, the patient developed cortical vision loss, atypical extrapyramidal features like segmental and hemifacial dystonia ultimately leading to a bedbound vegetative state. EEG showed typical periodic discharges along with positive cerebrospinal fluid serology for measles. PMID:23266775

Evolution of certain typical and atypical features in a case of subacute sclerosing panencephalitis.

PubMed

Raut, Tushar Premraj; Singh, Maneesh Kumar; Garg, Ravindra Kumar; Rai, Dheeraj

2012-12-23

Subacute sclerosing panencephalitis (SSPE) is a slowly progressive inflammatory disease of the central nervous system caused by a persistent measles virus usually affecting the childhood and adolescent age group. Clinical features at onset are very subtle and non-specific. Certain atypical features can occur at onset or during the course of illness which can be misleading. Neuroimaging features often are non-specific. Features like myoclonic jerks, cognitive decline and typical EEG findings lead to a strong suspicion of SSPE. Here, we describe the stagewise progression of a case of SSPE in a 14-year-old girl who had myoclonic jerks and cognitive decline at onset. During the course of disease, the patient developed cortical vision loss, atypical extrapyramidal features like segmental and hemifacial dystonia ultimately leading to a bedbound vegetative state. EEG showed typical periodic discharges along with positive cerebrospinal fluid serology for measles.

Diagnosing subtle palatal anomalies: Validation of video-analysis and assessment protocol for diagnosing occult submucous cleft palate.

PubMed

Rourke, Ryan; Weinberg, Seth M; Marazita, Mary L; Jabbour, Noel

2017-09-01

Submucous cleft palate (SMCP) classically involves bifid uvula, zona pellucida, and notched hard palate. However, patients may present with more subtle anatomic abnormalities. The ability to detect these abnormalities is important for surgeons managing velopharyngeal dysfunction (VPD) or considering adenoidectomy. Validate an assessment protocol for diagnosis of occult submucous cleft palate (OSMCP) and identify physical examination features present in patients with OSMCP in the relaxed and activated palate positions. Study participants included patients referred to a pediatric VPD clinic with concern for hypernasality or SMCP. Using an appropriately encrypted iPod touch, transoral video was obtained for each patient with the palate in the relaxed and activated positions. The videos were reviewed by two otolaryngologists in normal speed and slow-motion, as needed, and a questionnaire was completed by each reviewer pertaining to the anatomy and function of the palate. 47 patients, with an average age of 4.6 years, were included in the study over a one-year period. Four videos were unusable due to incomplete view of the palate. The most common palatal abnormality noted was OSMCP, diagnosed by each reviewer in 26/43 and 30/43 patients respectively. Using the assessment protocol, agreement on palatal diagnosis was 83.7% (kappa = 0.68), indicating substantial agreement, with the most prevalent anatomic features being vaulted palate elevation (96%) and visible notching of hard palate (75%). The diagnosis of subtle palatal anomalies is difficult and can be subjective. Using the proposed video-analysis method and assessment protocol may improve reliability of diagnosis of OSMCP. Copyright © 2017 Elsevier B.V. All rights reserved.

Efficient subtle motion detection from high-speed video for sound recovery and vibration analysis using singular value decomposition-based approach

NASA Astrophysics Data System (ADS)

Zhang, Dashan; Guo, Jie; Jin, Yi; Zhu, Chang'an

2017-09-01

High-speed cameras provide full field measurement of structure motions and have been applied in nondestructive testing and noncontact structure monitoring. Recently, a phase-based method has been proposed to extract sound-induced vibrations from phase variations in videos, and this method provides insights into the study of remote sound surveillance and material analysis. An efficient singular value decomposition (SVD)-based approach is introduced to detect sound-induced subtle motions from pixel intensities in silent high-speed videos. A high-speed camera is initially applied to capture a video of the vibrating objects stimulated by sound fluctuations. Then, subimages collected from a small region on the captured video are reshaped into vectors and reconstructed to form a matrix. Orthonormal image bases (OIBs) are obtained from the SVD of the matrix; available vibration signal can then be obtained by projecting subsequent subimages onto specific OIBs. A simulation test is initiated to validate the effectiveness and efficiency of the proposed method. Two experiments are conducted to demonstrate the potential applications in sound recovery and material analysis. Results show that the proposed method efficiently detects subtle motions from the video.

Isolated cortical visual loss with subtle brain MRI abnormalities in a case of hypoxic-ischemic encephalopathy.

PubMed

Margolin, Edward; Gujar, Sachin K; Trobe, Jonathan D

2007-12-01

A 16-year-old boy who was briefly asystolic and hypotensive after a motor vehicle accident complained of abnormal vision after recovering consciousness. Visual acuity was normal, but visual fields were severely constricted without clear hemianopic features. The ophthalmic examination was otherwise normal. Brain MRI performed 11 days after the accident showed no pertinent abnormalities. At 6 months after the event, brain MRI demonstrated brain volume loss in the primary visual cortex and no other abnormalities. One year later, visual fields remained severely constricted; neurologic examination, including formal neuropsychometric testing, was normal. This case emphasizes the fact that hypoxic-ischemic encephalopathy (HIE) may cause enduring damage limited to primary visual cortex and that the MRI abnormalities may be subtle. These phenomena should be recognized in the management of patients with HIE.

Perceptions of Sexual Orientation From Minimal Cues.

PubMed

Rule, Nicholas O

2017-01-01

People derive considerable amounts of information about each other from minimal nonverbal cues. Apart from characteristics typically regarded as obvious when encountering another person (e.g., age, race, and sex), perceivers can identify many other qualities about a person that are typically rather subtle. One such feature is sexual orientation. Here, I review the literature documenting the accurate perception of sexual orientation from nonverbal cues related to one's adornment, acoustics, actions, and appearance. In addition to chronicling studies that have demonstrated how people express and extract sexual orientation in each of these domains, I discuss some of the basic cognitive and perceptual processes that support these judgments, including how cues to sexual orientation manifest in behavioral (e.g., clothing choices) and structural (e.g., facial morphology) signals. Finally, I attend to boundary conditions in the accurate perception of sexual orientation, such as the states, traits, and group memberships that moderate individuals' ability to reliably decipher others' sexual orientation.

Exploitation of ERTS-1 imagery utilizing snow enhancement techniques

NASA Technical Reports Server (NTRS)

Wobber, F. J.; Martin, K. R.

1973-01-01

Photogeological analysis of ERTS-simulation and ERTS-1 imagery of snowcovered terrain within the ERAP Feather River site and within the New England (ERTS) test area provided new fracture detail which does not appear on available geological maps. Comparative analysis of snowfree ERTS-1 images has demonstrated that MSS Bands 5 and 7 supply the greatest amount of geological fracture detail. Interpretation of the first snow-covered ERTS-1 images in correlation with ground snow depth data indicates that a heavy blanket of snow (more than 9 inches) accentuates major structural features while a light "dusting", (less than 1 inch) accentuates more subtle topographic expressions. An effective mail-based method for acquiring timely ground-truth (snowdepth) information was established and provides a ready correlation of fracture detail with snow depth so as to establish the working limits of the technique. The method is both efficient and inexpensive compared with the cost of similarly scaled direct field observations.

Inorganic and Organometallic Molecular Wires for Single-Molecule Devices.

PubMed

Tanaka, Yuya; Kiguchi, Manabu; Akita, Munetaka

2017-04-06

Recent developments of single-molecule conductance measurements allow us to understand fundamental conducting properties of molecular wires. While a wide variety of organic molecular wires have been studied so far, inorganic and organometallic molecular wires have received much less attention. However, molecular wires with transition-metal atoms show interesting features and functions distinct from those of organic wires. These properties originate mainly from metal-ligand dπ-pπ interactions and metal-metal d-d interactions. Thanks to the rich combination of metal atoms and supporting ligands, frontier orbital energies of the molecular wires can be finely tuned to lead to highly conducting molecular wires. Moreover, the unique electronic structures of metal complexes are susceptible to subtle environmental changes, leading to potential functional molecular devices. This article reviews recent advances in the single-molecule conductance study of inorganic and organometallic molecular wires. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dispersion-cancelled biological imaging with quantum-inspired interferometry

PubMed Central

Mazurek, M. D.; Schreiter, K. M.; Prevedel, R.; Kaltenbaek, R.; Resch, K. J.

2013-01-01

Quantum information science promises transformative impact over a range of key technologies in computing, communication, and sensing. A prominent example uses entangled photons to overcome the resolution-degrading effects of dispersion in the medical-imaging technology, optical coherence tomography. The quantum solution introduces new challenges: inherently low signal and artifacts, additional unwanted signal features. It has recently been shown that entanglement is not a requirement for automatic dispersion cancellation. Such classical techniques could solve the low-signal problem, however they all still suffer from artifacts. Here, we introduce a method of chirped-pulse interferometry based on shaped laser pulses, and use it to produce artifact-free, high-resolution, dispersion-cancelled images of the internal structure of a biological sample. Our work fulfills one of the promises of quantum technologies: automatic-dispersion-cancellation interferometry in biomedical imaging. It also shows how subtle differences between a quantum technique and its classical analogue may have unforeseen, yet beneficial, consequences. PMID:23545597

The new "new racism" thesis: limited government values and race-conscious policy attitudes.

PubMed

Gainous, Jason

2012-01-01

Some contend that Whites’ application of values to form opinions about race-conscious policy may constitute a subtle form of racism. Others challenge the new racism thesis, suggesting that racism and values are exclusive in their influence. Proponents of the thesis assert that many Whites’ attitudes about such policy are structured by a mix of racism and American individualism. The author suggests that an even more subtle form of racism may exist. Racism may actually be expressed in opposition to big government. The test results presented here indicate that the effects of limited-government values on attitudes about race-conscious policy are conditional on levels of racial prejudice for many Whites, whereas the effects on racially ambiguous social welfare policy attitudes are not. The author contends that these results provide support to the argument that racism still exists and has found a new subtle expression.

Managing Diversity.

ERIC Educational Resources Information Center

Geber, Beverly

1990-01-01

Demographic trends imply that organizations must learn to manage a diverse work force. Ways to change organizational systems, structures, and practices to eliminate subtle barriers are awareness training, attitude change, and valuing diversity. (SK)

Mega-geomorphology and neotectonics

NASA Technical Reports Server (NTRS)

Lattman, L. H.

1985-01-01

For several decades, subtle neotectonic effects involving several square kilometers have been studied in detail using remote sensing, primarily various types of stereo-aerial photographs at scales of 1:10,000 to 1:80,000. These subtle effects, especially local uplifts associated with growing structures of differential compaction, have been detected by the effect on drainage patterns, changes in hydraulic geometry of individuals channels or groups of channels, tonal halos (soil) and fracture patterns. The studies were extended with the advent of thermal IR imagery particularly in tonal analysis, and SLAR primarily in fracture pattern studies. Lately, quantitative efforts have begun attempting to link measured uplift over known structures with measured changes in hydraulic geometry and alluvial deposition. Thus, efforts are now underway attempting to quantify the relationship between neo- (micro-) tectonic changes and geomorphic parameters of drainage systems.

Subtle Changes in Peptide Conformation Profoundly Affect Recognition of the Non-Classical MHC Class I Molecule HLA-E by the CD94-NKG2 Natural Killer Cell Receptors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoare, Hilary L; Sullivan, Lucy C; Clements, Craig S

2008-03-31

Human leukocyte antigen (HLA)-E is a non-classical major histocompatibility complex class I molecule that binds peptides derived from the leader sequences of other HLA class I molecules. Natural killer cell recognition of these HLA-E molecules, via the CD94-NKG2 natural killer family, represents a central innate mechanism for monitoring major histocompatibility complex expression levels within a cell. The leader sequence-derived peptides bound to HLA-E exhibit very limited polymorphism, yet subtle differences affect the recognition of HLA-E by the CD94-NKG2 receptors. To better understand the basis for this peptide-specific recognition, we determined the structure of HLA-E in complex with two leader peptides,more » namely, HLA-Cw*07 (VMAPRALLL), which is poorly recognised by CD94-NKG2 receptors, and HLA-G*01 (VMAPRTLFL), a high-affinity ligand of CD94-NKG2 receptors. A comparison of these structures, both of which were determined to 2.5-Å resolution, revealed that allotypic variations in the bound leader sequences do not result in conformational changes in the HLA-E heavy chain, although subtle changes in the conformation of the peptide within the binding groove of HLA-E were evident. Accordingly, our data indicate that the CD94-NKG2 receptors interact with HLA-E in a manner that maximises the ability of the receptors to discriminate between subtle changes in both the sequence and conformation of peptides bound to HLA-E.« less

Modeling Seasonal Thermal Radiance Cycles for Change Detection at Volcanic / Geothermal Areas

NASA Astrophysics Data System (ADS)

Vaughan, R.; Beuttel, B. S.

2013-12-01

Remote sensing observations of thermal features associated with (and often preceding) volcanic activity have been used for decades to detect and monitor volcanism. However, anomalous thermal precursors to volcanic eruptions are usually only recognized retrospectively. One of the reasons for this is that precursor thermal activity is often too subtle in magnitude (spatially, temporally, or in absolute temperature) to be unambiguously detected in time to issue warnings or forecasts. Part of the reason for this is the trade-off between high spatial and high temporal resolution associated with satellite imaging systems. Thus, the goal of this work has been to develop some techniques for using high-temporal-resolution, coarse-spatial-resolution imagery to try to detect subtle thermal anomalies. To identify anomalies, background thermal activity must first be characterized. Every active, or potentially active, volcano has a unique thermal history that provides information about normal background thermal activity due to seasonal or diurnal variations. Understanding these normal variations allows recognition of anomalous activity that may be due to volcanic / hydrothermal processes - ultimately with a lead time that may be sufficient to issue eruption warnings or forecasts. Archived MODIS data, acquired ~daily from 2000 to 2012, were used to investigate seasonal thermal cycles at three volcanic areas with different types of thermal features: Mount St. Helens, which had a dacite dome-building eruption from 2004-2008; Mount Ruapehu, which has a 500-m diameter active summit crater lake; and Yellowstone, which is a large active geothermal system that has hundreds of hot springs and fumarole fields spread out over a very large area. The focus has been on using MODIS 1-km sensor radiance data in the MIR and TIR wavelength regions that are sensitive to thermal emission from features that range in temperature from hundreds of °C, down to tens of °C (below the boiling temperature of water). To detect such features it is best to use data acquired at night, as this maximizes the delta T between the thermal target and non-thermal background and minimizes the effects of the Sun. Decadal time-series plots of nighttime MODIS sensor radiance data over the target areas show that seasonal thermal cycles due to varying solar incidence angle can be modeled with a sine function and removed to reveal subtle changes in TIR radiance. The seasonal sine function is unique to each volcanic / geothermal area and can be modeled iteratively using a least squares fit to the cloud of radiance data. The sine function model can also be used to generate a first-order cloud cover approximation for the nighttime TIR data. This work helps establish a framework for improved thermal alarm algorithms, automated thermal detection methods, and operational monitoring techniques for active, or potentially active, volcanoes throughout the world. This type of background study is a step toward establishing a global volcanic eruption forecasting system using satellite-based remote sensing data that are sensitive to subtle precursor thermal anomalies.

Pronounced differences in genetic structure despite overall ecological similarity for two Ambystoma salamanders in the same landscape

Treesearch

Andrew R. Whiteley; Kevin McGarigal; Michael K. Schwartz

2014-01-01

Studies linking genetic structure in amphibian species with ecological characteristics have focused on large differences in dispersal capabilities. Here, we test whether two species with similar dispersal potential but subtle differences in other ecological characteristics also exhibit strong differences in genetic structure in the same landscape. We examined eight...

Problems in understanding the structure and assembly of viruses

DOE Office of Scientific and Technical Information (OSTI.GOV)

King, J.

1997-12-01

Though viruses infect the cells of all groups of animals, plants, and microorganisms, their structures follow a limited number of general themes; spherical or cylindrical shells built of hundreds of repeated protein subunits enclosing a nucleic acid - DNA or RNA - genome. Since the 1960s it has been known that the protein shells of spherical viruses in fact conform to icosahedral symmetry or to subtle deviations from icosahedral symmetry. The construction of the shell lattices and the transformations they go through in the different stages of the viral life cycle are not fully understood. The shells contain the nucleicmore » in a highly condensed state, of unknown coiling/organization. Features of the well studied bacterial viruses will be reviewed, with examples from adenoviruses, herpesviruses, poliovirus, and HIV. The emergence of new viral disease has led to increased interest in the development of agents which interfere with virus reproduction at the level of the assembly or function of the organized particle. Recently computational approaches to the problem of virus assembly have made important contributions to clarifying shell assembly processes. 1 ref.« less

Visualization of the structural response of a hypersonic turbulent boundary layer to convex curvature

NASA Astrophysics Data System (ADS)

Humble, R. A.; Peltier, S. J.; Bowersox, R. D. W.

2012-10-01

The effects of convex curvature on the outer structure of a Mach 4.9 turbulent boundary layer (Reθ = 4.7 × 104) are investigated using condensate Rayleigh scattering and analyzed using spatial correlations, intermittency, and fractal theory. It is found that the post-expansion boundary layer structure morphology appears subtle, but certain features exhibit a more obvious response. The large-scale flow structures survive the initial expansion, appearing to maintain the same physical size. However, due to the nature of the expansion fan, a differential acceleration effect takes place across the flow structures, causing them to be reoriented, leaning farther away from the wall. The onset of intermittency moves closer towards the boundary layer edge and the region of intermittent flow decreases. It is likely that this reflects the less frequent penetration of outer irrotational fluid into the boundary layer, consistent with a boundary layer that is losing its ability to entrain freestream fluid. The fractal dimension of the turbulent/nonturbulent interface decreases with increasing favorable pressure gradient, indicating that the interface's irregularity decreases. Because fractal scale similarity does not encompass the largest scales, this suggests that the change in fractal dimension is due to the action of the smaller-scales, consistent with the idea that the small-scale flow structures are quenched during the expansion in response to bulk dilatation.

Airborne imaging spectrometer data of the Ruby Mountains, Montana: Mineral discrimination using relative absorption band-depth images

USGS Publications Warehouse

Crowley, J.K.; Brickey, D.W.; Rowan, L.C.

1989-01-01

Airborne imaging spectrometer data collected in the near-infrared (1.2-2.4 ??m) wavelength range were used to study the spectral expression of metamorphic minerals and rocks in the Ruby Mountains of southwestern Montana. The data were analyzed by using a new data enhancement procedure-the construction of relative absorption band-depth (RBD) images. RBD images, like bandratio images, are designed to detect diagnostic mineral absorption features, while minimizing reflectance variations related to topographic slope and albedo differences. To produce an RBD image, several data channels near an absorption band shoulder are summed and then divided by the sum of several channels located near the band minimum. RBD images are both highly specific and sensitive to the presence of particular mineral absorption features. Further, the technique does not distort or subdue spectral features as sometimes occurs when using other data normalization methods. By using RBD images, a number of rock and soil units were distinguished in the Ruby Mountains including weathered quartz - feldspar pegmatites, marbles of several compositions, and soils developed over poorly exposed mica schists. The RBD technique is especially well suited for detecting weak near-infrared spectral features produced by soils, which may permit improved mapping of subtle lithologic and structural details in semiarid terrains. The observation of soils rich in talc, an important industrial commodity in the study area, also indicates that RBD images may be useful for mineral exploration. ?? 1989.

Evaluating some computer exhancement algorithms that improve the visibility of cometary morphology

NASA Technical Reports Server (NTRS)

Larson, Stephen M.; Slaughter, Charles D.

1992-01-01

Digital enhancement of cometary images is a necessary tool in studying cometary morphology. Many image processing algorithms, some developed specifically for comets, have been used to enhance the subtle, low contrast coma and tail features. We compare some of the most commonly used algorithms on two different images to evaluate their strong and weak points, and conclude that there currently exists no single 'ideal' algorithm, although the radial gradient spatial filter gives the best overall result. This comparison should aid users in selecting the best algorithm to enhance particular features of interest.

Pathologic features of early inflammatory bowel disease.

PubMed

Finkelstein, Sydney D; Sasatomi, Eizaburo; Regueiro, Miguel

2002-03-01

Often the pathologic changes of IBD are subtle and may not be present in a proportion of biopsy specimens. In cases of early disease, the changes may be missed, and additional specimens should be taken after a period of time. Modifying factors, such as prebiopsy treatment and coexisting disease, should be considered. A forum to review cases and allow for communication between gastroenterologists and pathologists is especially useful for clinicopathologic correlation and assignment of a working diagnosis to each case. Careful attention to the pathologic features of early UC and CD would be most useful when evaluating new therapies for IBD.

Mineral shock signatures in rocks from Dhala (Mohar) impact structure, Shivpuri district, Madhya Pradesh, India

NASA Astrophysics Data System (ADS)

Roy, Madhuparna; Pandey, Pradeep; Kumar, Shailendra; Parihar, P. S.

2017-12-01

A concrete study combining optical microscopy, Raman spectroscopy and X-ray diffractometry, was carried out on subsurface samples of basement granite and melt breccia from Mohar (Dhala) impact structure, Shivpuri district, Madhya Pradesh, India. Optical microscopy reveals aberrations in the optical properties of quartz and feldspar in the form of planar deformation feature-like structures, lowered birefringence and mosaics in quartz, toasting, planar fractures and ladder texture in alkali feldspar and near-isotropism in bytownite. It also brings to light incidence of parisite, a radioactive rare mineral in shocked granite. Raman spectral pattern, peak positions, peak widths and multiplicity of peak groups of all minerals, suggest subtle structural/crystallographic deviations. XRD data further reveals minute deviations of unit cell parameters of quartz, alkali feldspar and plagioclase, with respect to standard α-quartz, high- and low albite and microcline. Reduced cell volumes in these minerals indicate compression due to pressure. The c0/a0 values indicate an inter-tetrahedral angle roughly between 120o and 144o, further pointing to a possible pressure maxima of around 12 GPa. The observed unit cell aberration of minerals may indicate an intermediate stage between crystalline and amorphous stages, thereby, signifying possible overprinting of decompression signatures over shock compression effects, from a shock recovery process.

Molecular basis for the Kallmann syndrome-linked fibroblast growth factor receptor mutation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thurman, Ryan D.; Kathir, Karuppanan Muthusamy; Rajalingam, Dakshinamurthy

Highlights: Black-Right-Pointing-Pointer The structural basis of the Kallmann syndrome is elucidated. Black-Right-Pointing-Pointer Kallmann syndrome mutation (A168S) induces a subtle conformational change(s). Black-Right-Pointing-Pointer Structural interactions mediated by beta-sheet G are most perturbed. Black-Right-Pointing-Pointer Ligand (FGF)-receptor interaction(s) is completely abolished by Kallmann mutation. Black-Right-Pointing-Pointer Kallmann mutation directly affects the FGF signaling process. -- Abstract: Kallmann syndrome (KS) is a developmental disease that expresses in patients as hypogonadotropic hypogonadism and anosmia. KS is commonly associated with mutations in the extracellular D2 domain of the fibroblast growth factor receptor (FGFR). In this study, for the first time, the molecular basis for the FGFR associatedmore » KS mutation (A168S) is elucidated using a variety of biophysical experiments, including multidimensional NMR spectroscopy. Secondary and tertiary structural analysis using far UV circular dichroism, fluorescence and limited trypsin digestion assays suggest that the KS mutation induces subtle tertiary structure change in the D2 domain of FGFR. Results of isothermal titration calorimetry experiments show the KS mutation causes a 10-fold decrease in heparin binding affinity and also a complete loss in ligand (FGF-1) binding. {sup 1}H-{sup 15}N chemical perturbation data suggest that complete loss in the ligand (FGF) binding affinity is triggered by a subtle conformational change that disrupts crucial structural interactions in both the heparin and the FGF binding sites in the D2 domain of FGFR. The novel findings reported in this study are expected to provide valuable clues toward a complete understanding of the other genetic diseases linked to mutations in the FGFR.« less

Brief Report: CANTAB Performance and Brain Structure in Pediatric Patients with Asperger Syndrome

ERIC Educational Resources Information Center

Kaufmann, Liane; Zotter, Sibylle; Pixner, Silvia; Starke, Marc; Haberlandt, Edda; Steinmayr-Gensluckner, Maria; Egger, Karl; Schocke, Michael; Weiss, Elisabeth M.; Marksteiner, Josef

2013-01-01

By merging neuropsychological (CANTAB/Cambridge Neuropsychological Test Automated Battery) and structural brain imaging data (voxel-based-morphometry) the present study sought to identify the neurocognitive correlates of executive functions in individuals with Asperger syndrome (AS) compared to healthy controls. Results disclosed subtle group…

Crystallographic structure refinement with quadrupolar nuclei: a combined solid-state NMR and GIPAW DFT example using MgBr(2).

PubMed

Widdifield, Cory M; Bryce, David L

2009-09-07

Solid-state NMR spectroscopy and GIPAW DFT calculations reveal the pronounced sensitivity of (79/81)Br and (25)Mg quadrupolar coupling constants to subtle aspects of solid state structure which were not previously detected by pXRD methods.

A Study of Cognitive Linguistic Structure Based on the Four Conditions of the Mulamadhyamakakarika

ERIC Educational Resources Information Center

You, Hee Jong

2013-01-01

The main purpose of this study is to depict Nagarjuna's implication on how he redefined the Four Conditions ("atvarah pratyaya") as the cognitive linguistic structure by allocating 32 functional metadata throughout the texts of Mulamadhyamakakarika (MMK). Following subtle traces of "okasamvrtisatya" (the conventional truth) in…

Phenotype detection in morphological mutant mice using deformation features.

PubMed

Roy, Sharmili; Liang, Xi; Kitamoto, Asanobu; Tamura, Masaru; Shiroishi, Toshihiko; Brown, Michael S

2013-01-01

Large-scale global efforts are underway to knockout each of the approximately 25,000 mouse genes and interpret their roles in shaping the mammalian embryo. Given the tremendous amount of data generated by imaging mutated prenatal mice, high-throughput image analysis systems are inevitable to characterize mammalian development and diseases. Current state-of-the-art computational systems offer only differential volumetric analysis of pre-defined anatomical structures between various gene-knockout mice strains. For subtle anatomical phenotypes, embryo phenotyping still relies on the laborious histological techniques that are clearly unsuitable in such big data environment. This paper presents a system that automatically detects known phenotypes and assists in discovering novel phenotypes in muCT images of mutant mice. Deformation features obtained from non-linear registration of mutant embryo to a normal consensus average image are extracted and analyzed to compute phenotypic and candidate phenotypic areas. The presented system is evaluated using C57BL/10 embryo images. All cases of ventricular septum defect and polydactyly, well-known to be present in this strain, are successfully detected. The system predicts potential phenotypic areas in the liver that are under active histological evaluation for possible phenotype of this mouse line.

HiCRep: assessing the reproducibility of Hi-C data using a stratum-adjusted correlation coefficient.

PubMed

Yang, Tao; Zhang, Feipeng; Yardımcı, Galip Gürkan; Song, Fan; Hardison, Ross C; Noble, William Stafford; Yue, Feng; Li, Qunhua

2017-11-01

Hi-C is a powerful technology for studying genome-wide chromatin interactions. However, current methods for assessing Hi-C data reproducibility can produce misleading results because they ignore spatial features in Hi-C data, such as domain structure and distance dependence. We present HiCRep, a framework for assessing the reproducibility of Hi-C data that systematically accounts for these features. In particular, we introduce a novel similarity measure, the stratum adjusted correlation coefficient (SCC), for quantifying the similarity between Hi-C interaction matrices. Not only does it provide a statistically sound and reliable evaluation of reproducibility, SCC can also be used to quantify differences between Hi-C contact matrices and to determine the optimal sequencing depth for a desired resolution. The measure consistently shows higher accuracy than existing approaches in distinguishing subtle differences in reproducibility and depicting interrelationships of cell lineages. The proposed measure is straightforward to interpret and easy to compute, making it well-suited for providing standardized, interpretable, automatable, and scalable quality control. The freely available R package HiCRep implements our approach. © 2017 Yang et al.; Published by Cold Spring Harbor Laboratory Press.

Surface Curvature Relation to Protein Adsorption for Carbon-based Nanomaterials

NASA Astrophysics Data System (ADS)

Gu, Zonglin; Yang, Zaixing; Chong, Yu; Ge, Cuicui; Weber, Jeffrey K.; Bell, David R.; Zhou, Ruhong

2015-06-01

The adsorption of proteins onto carbon-based nanomaterials (CBNs) is dictated by hydrophobic and π-π interactions between aliphatic and aromatic residues and the conjugated CBN surface. Accordingly, protein adsorption is highly sensitive to topological constraints imposed by CBN surface structure; in particular, adsorption capacity is thought to increase as the incident surface curvature decreases. In this work, we couple Molecular Dynamics (MD) simulations with fluorescence spectroscopy experiments to characterize this curvature dependence in detail for the model protein bovine serum albumin (BSA). By studying BSA adsorption onto carbon nanotubes of increasing radius (featuring descending local curvatures) and a flat graphene sheet, we confirm that adsorption capacity is indeed enhanced on flatter surfaces. Naïve fluorescence experiments featuring multi-walled carbon nanotubes (MWCNTs), however, conform to an opposing trend. To reconcile these observations, we conduct additional MD simulations with MWCNTs that match those prepared in experiments; such simulations indicate that increased mass to surface area ratios in multi-walled systems explain the observed discrepancies. In reduction, our work substantiates the inverse relationship between protein adsorption capacity and surface curvature and further demonstrates the need for subtle consideration in experimental and simulation design.

Molecular structure of self-assembled chiral nanoribbons and nanotubules revealed in the hydrated state.

PubMed

Oda, Reiko; Artzner, Franck; Laguerre, Michel; Huc, Ivan

2008-11-05

A detailed molecular organization of racemic 16-2-16 tartrate self-assembled multi-bilayer ribbons in the hydrated state is proposed where 16-2-16 amphiphiles, tartrate ions, and water molecules are all accurately positioned by comparing experimental X-ray powder diffraction and diffraction patterns derived from modeling studies. X-ray diffuse scattering studies show that molecular organization is not fundamentally altered when comparing the flat ribbons of the racemate to chirally twisted or helical ribbons of the pure tartrate enantiomer. Essential features of the three-dimensional molecular organizations of these structures include interdigitation of alkyl chains within each bilayer and well-defined networks of ionic and hydrogen bonds between cations, anions, and water molecules between bilayers. The detailed study of diffraction patterns also indicated that the gemini headgroups are oriented parallel to the long edge of the ribbons. The structure thus possesses a high cohesion and good crystallinity, and for the first time, we could relate the packing of the chiral molecules to the expression of the chirality at a mesoscopic scale. The organization of the ribbons at the molecular level sheds light on a number of their macroscopic features. Among these are the reason why enantiomerically pure 16-2-16 tartrate forms ribbons that consist of exactly two bilayers, and a plausible mechanism by which a chirally twisted or helical shape may emerge from the packing of chiral tartrate ions. Importantly, the distinction between commonly observed helical and twisted morphologies could be related to a subtle symmetry breaking. These results demonstrate that accurately solving the molecular structure of self-assembled soft materials--a process rarely achieved--is within reach, that it is a valid approach to correlate molecular parameters to macroscopic properties, and thus that it offers opportunities to modulate properties through molecular design.

Painting with Frost

NASA Image and Video Library

2016-12-07

Subtle variations in color look like brush strokes as the lightly frosted terrain reflects light. These variations provide a backdrop to some exotic features referred to colloquially as "spiders." The radial channels branching out from a central depression are formed when the seasonal layer of dry ice turns to gas in the spring and erodes the surface, which is a uniquely Martian landform. http://photojournal.jpl.nasa.gov/catalog/PIA21214

SEAFLOOR MANIFESTATIONS OF GAS VENTING AND NEAR SEAFLOOR GAS HYDRATE OCCURRENCES

NASA Astrophysics Data System (ADS)

Paull, C. K.; Ussler, W.; Caress, D. W.; Thomas, H.; Lundsten, E.; Riedel, M.; Lapham, L.

2009-12-01

High-resolution multibeam bathymetry and chirp seismic profiles collected with an AUV complimented by ROV observations and sampling reveal the fine scale geomorphology and seafloor structures associated with gas venting and/or near subsurface gas hydrate accumulations along the Pacific North American continental margin. Sites from Santa Monica Basin, northern and southern Hydrate Ridge, Barkley Canyon, Bullseye Vent and three previously unexplored vent sites near Bullseye Vent have been recently investigated. The new AUV data allow the identification of features and seafloor textures that were previously undetected and reveal the impact of gas venting, gas hydrate development and related phenomena on the seafloor morphology. Distinct geomorphic characteristics are interpreted to represent different stages in the development and evolution of the seafloor in these areas. The more mature features include distinct (>10 m high) elevated features (e.g., Santa Monica Mounds and the Hydrate Ridge Pinnacle), widespread areas where methane-derived carbonates are exposed on the surrounding seafloor (e.g., both Hydrate Ridge sites, and an unnamed ridge north of Bullseye Vent), circular seafloor craters with diameters of 3 to 50 m that appear to be associated with missing sections of the original seafloor (e.g., Bullseye Vent, northern Hydrate Ridge, and an unnamed ridge north of Bullseye Vent). Smaller mound-like features (<10 m in diameter and 1-3 m higher than the surrounding seafloor occur at Barkley Canyon and a newly explored vent system called Spinnaker Vent 6 km NW of Bullseye vent. Solid lens of gas hydrate are occasionally exposed along fractures on the sides of these mounds and suggest that these are push-up features associated with gas hydrate growth within the near seafloor sediments. The existence of both extensive methane-derived carbonates and chemosynthetic biological communities characterized by Vesicomya clams and Lamellibrachia tubeworms (which are slow growing) indicate that methane venting has occurred for protracted periods of time at these sites. However, the youngest appearing features occur in a gulch ~1 km NE of Bullseye Vent. They are associated with more-subtle (2-3 m in diameter and ~0.5 m high) seafloor mounds, with their crests crossed with small cracks lined with white bacterial mats, lack exposed methane-derived carbonates, Vesicomya clams or Lamellibrachia tubeworms. ROV-collected vibracores (<1.5 cm long) obtained from these subtle mounds characteristically encountered a hard layer at 30-60 cm sub-bottom. Where this layer was penetrated, methane bubbles would spontaneously gush out the hole and continue to flow out for more than an hour. These observations suggest that these small mounds are young features which have considerable volumes of over-pressured gas trapped near the seafloor. Together these observations reveal the integrated effect that gas and/or gas hydrate occurrences can have on the seafloor. The existence of apparently over-pressured gas within ~1 m of the seafloor has intriguing implications as to the geo-hazard potential of such sites.

Applications of ICA and fractal dimension in sEMG signal processing for subtle movement analysis: a review.

PubMed

Naik, Ganesh R; Arjunan, Sridhar; Kumar, Dinesh

2011-06-01

The surface electromyography (sEMG) signal separation and decphompositions has always been an interesting research topic in the field of rehabilitation and medical research. Subtle myoelectric control is an advanced technique concerned with the detection, processing, classification, and application of myoelectric signals to control human-assisting robots or rehabilitation devices. This paper reviews recent research and development in independent component analysis and Fractal dimensional analysis for sEMG pattern recognition, and presents state-of-the-art achievements in terms of their type, structure, and potential application. Directions for future research are also briefly outlined.

Plant phenolics and absorption features in vegetation reflectance spectra near 1.66 μm

NASA Astrophysics Data System (ADS)

Kokaly, Raymond F.; Skidmore, Andrew K.

2015-12-01

Past laboratory and field studies have quantified phenolic substances in vegetative matter from reflectance measurements for understanding plant response to herbivores and insect predation. Past remote sensing studies on phenolics have evaluated crop quality and vegetation patterns caused by bedrock geology and associated variations in soil geochemistry. We examined spectra of pure phenolic compounds, common plant biochemical constituents, dry leaves, fresh leaves, and plant canopies for direct evidence of absorption features attributable to plant phenolics. Using spectral feature analysis with continuum removal, we observed that a narrow feature at 1.66 μm is persistent in spectra of manzanita, sumac, red maple, sugar maple, tea, and other species. This feature was consistent with absorption caused by aromatic Csbnd H bonds in the chemical structure of phenolic compounds and non-hydroxylated aromatics. Because of overlapping absorption by water, the feature was weaker in fresh leaf and canopy spectra compared to dry leaf measurements. Simple linear regressions of feature depth and feature area with polyphenol concentration in tea resulted in high correlations and low errors (% phenol by dry weight) at the dry leaf (r2 = 0.95, RMSE = 1.0%, n = 56), fresh leaf (r2 = 0.79, RMSE = 2.1%, n = 56), and canopy (r2 = 0.78, RMSE = 1.0%, n = 13) levels of measurement. Spectra of leaves, needles, and canopies of big sagebrush and evergreens exhibited a weak absorption feature centered near 1.63 μm, short ward of the phenolic compounds, possibly consistent with terpenes. This study demonstrates that subtle variation in vegetation spectra in the shortwave infrared can directly indicate biochemical constituents and be used to quantify them. Phenolics are of lesser abundance compared to the major plant constituents but, nonetheless, have important plant functions and ecological significance. Additional research is needed to advance our understanding of the spectral influences of plant phenolics and terpenes relative to dominant leaf biochemistry (water, chlorophyll, protein/nitrogen, cellulose, and lignin).

TBC1D24 mutation associated with focal epilepsy, cognitive impairment and a distinctive cerebro-cerebellar malformation.

PubMed

Afawi, Zaid; Mandelstam, Simone; Korczyn, Amos D; Kivity, Sara; Walid, Simri; Shalata, Adel; Oliver, Karen L; Corbett, Mark; Gecz, Jozef; Berkovic, Samuel F; Jackson, Graeme D

2013-07-01

We describe the clinical and radiological features of a family with a homozygous mutation in TBC1D24. The phenotype comprised onset of focal seizures at 2 months with prominent eye-blinking, facial and limb jerking with an oral sensory aura. These were controllable with medication but persisted into adult life. Associated features were mild to moderate intellectual disability and cerebellar features. MRI showed subtle cortical thickening with cerebellar atrophy and high signal confined to the ansiform lobule. The disorder is allelic with familial infantile myoclonic epilepsy, where intellect and neurologic examination are normal, highlighting the phenotypic variation with mutations of TBC1D24. Copyright © 2013 Elsevier B.V. All rights reserved.

Composition and structure of fresh ammonia clouds on Jupiter based on quantitative analysis of Galileo/NIMS and New Horizons/LEISA spectra

NASA Astrophysics Data System (ADS)

Sromovsky, L. A.; Fry, P. M.

2018-06-01

Ammonia gas has long been assumed to be the main source of condensables for the upper cloud layer on Jupiter, but distinctive spectral features associated with ammonia have been seen only rarely. Since both ammonia and NH4SH absorb in the 3 μm region, and widespread absorption in the 3 μm region was present (Sromovsky and Fry, 2010), identification of the 2 μm absorption feature of NH3 provided an opportunity to clearly establish its presence in Jovian clouds. Baines et al. (2002) succeeded in finding in Near Infrared Mapping Spectrometer (NIMS) observations one feature that had both 2 μm and 3 μm absorption, and many which were known to have absorption at 2.73 μm. They named these Spectrally Identifiable Ammonia Clouds (SIACs). They also argued that these were fresh ammonia clouds that would eventually succumb to some process that would obscure their absorption features. Detection of many more of the 2 μm features was later achieved by New Horizon's Linear Etalon Imaging Spectral Array (LEISA) instrument, which provided both the spatial and spectral resolution needed to identify these features. Here we report on the first quantitative modeling that uses NIMS spectra over a broad (1-5.2 μm) spectral range and LEISA spectra over a much narrower (1.25-2.5 μm) spectral range to constrain the cloud structure and composition of these rare cloud features and compare them to background clouds. We find that the absorption signature at 2 μm, which is well characterized in LEISA spectra, is relatively subtle and easily matched by model clouds containing spherical particles of ammonia ice with radii of 2-4 μm. The NIMS spectra, which cover both reflected sunlight as well as thermal emission regions are more difficult to model with cloud materials plausibly present in Jupiter's atmosphere. The best signal/noise spectra obtained from NIMS provide a relatively sparse sampling of the spectrum, which does not establish the detailed shape of the 3 μm absorption region. NIMS SIAC spectra with much denser spectral sampling are limited by much higher noise levels that degrade the features that are key to identifying cloud composition. The structure which best matches the wide range NIMS SIAC spectra contains two overlapping NH3 clouds with a bi-modal size distribution over an optically thick NH4SH cloud. The bi-modal distribution may be a result of modeling non-spherical, possibly fractal aggregate, particles with spheres.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Honorio, J.; Goldstein, R.; Honorio, J.

We propose a simple, well grounded classification technique which is suited for group classification on brain fMRI data sets that have high dimensionality, small number of subjects, high noise level, high subject variability, imperfect registration and capture subtle cognitive effects. We propose threshold-split region as a new feature selection method and majority voteas the classification technique. Our method does not require a predefined set of regions of interest. We use average acros ssessions, only one feature perexperimental condition, feature independence assumption, and simple classifiers. The seeming counter-intuitive approach of using a simple design is supported by signal processing and statisticalmore » theory. Experimental results in two block design data sets that capture brain function under distinct monetary rewards for cocaine addicted and control subjects, show that our method exhibits increased generalization accuracy compared to commonly used feature selection and classification techniques.« less

Crystal and Molecular Structure of a Collagen-Like Peptide at 1.9 overset{circ}{A} Resolution

NASA Astrophysics Data System (ADS)

Bella, Jordi; Eaton, Mark; Brodsky, Barbara; Berman, Helen M.

1994-10-01

The structure of a protein triple helix has been determined at 1.9 angstrom resolution by x-ray crystallographic studies of a collagen-like peptide containing a single substitution of the consensus sequence. This peptide adopts a triple-helical structure that confirms the basic features determined from fiber diffraction studies on collagen: supercoiling of polyproline II helices and interchain hydrogen bonding that follows the model II of Rich and Crick. In addition, the structure provides new information concerning the nature of this protein fold. Each triple helix is surrounded by a cylinder of hydration, with an extensive hydrogen bonding network between water molecules and peptide acceptor groups. Hydroxyproline residues have a critical role in this water network. The interaxial spacing of triple helices in the crystal is similar to that in collagen fibrils, and the water networks linking adjacent triple helices in the crystal structure are likely to be present in connective tissues. The breaking of the repeating (X-Y-Gly)_n pattern by a Gly-->Ala substitution results in a subtle alteration of the conformation, with a local untwisting of the triple helix. At the substitution site, direct interchain hydrogen bonds are replaced with interstitial water bridges between the peptide groups. Similar conformational changes may occur in Gly-->X mutated collagens responsible for the diseases osteogenesis imperfecta, chondrodysplasias, and Ehlers-Danlos syndrome IV.

Neurally Derived Tissues in Xenopus laevis Embryos Exhibit a Consistent Bioelectrical Left-Right Asymmetry

PubMed Central

Pai, Vaibhav P.; Vandenberg, Laura N.; Blackiston, Douglas; Levin, Michael

2012-01-01

Consistent left-right asymmetry in organ morphogenesis is a fascinating aspect of bilaterian development. Although embryonic patterning of asymmetric viscera, heart, and brain is beginning to be understood, less is known about possible subtle asymmetries present in anatomically identical paired structures. We investigated two important developmental events: physiological controls of eye development and specification of neural crest derivatives, in Xenopus laevis embryos. We found that the striking hyperpolarization of transmembrane potential (V mem) demarcating eye induction usually occurs in the right eye field first. This asymmetry is randomized by perturbing visceral left-right patterning, suggesting that eye asymmetry is linked to mechanisms establishing primary laterality. Bilateral misexpression of a depolarizing channel mRNA affects primarily the right eye, revealing an additional functional asymmetry in the control of eye patterning by V mem. The ATP-sensitive K+ channel subunit transcript, SUR1, is asymmetrically expressed in the eye primordia, thus being a good candidate for the observed physiological asymmetries. Such subtle asymmetries are not only seen in the eye: consistent asymmetry was also observed in the migration of differentiated melanocytes on the left and right sides. These data suggest that even anatomically symmetrical structures may possess subtle but consistent laterality and interact with other developmental left-right patterning pathways. PMID:23346115

Neurally Derived Tissues in Xenopus laevis Embryos Exhibit a Consistent Bioelectrical Left-Right Asymmetry.

PubMed

Pai, Vaibhav P; Vandenberg, Laura N; Blackiston, Douglas; Levin, Michael

2012-01-01

Consistent left-right asymmetry in organ morphogenesis is a fascinating aspect of bilaterian development. Although embryonic patterning of asymmetric viscera, heart, and brain is beginning to be understood, less is known about possible subtle asymmetries present in anatomically identical paired structures. We investigated two important developmental events: physiological controls of eye development and specification of neural crest derivatives, in Xenopus laevis embryos. We found that the striking hyperpolarization of transmembrane potential (V(mem)) demarcating eye induction usually occurs in the right eye field first. This asymmetry is randomized by perturbing visceral left-right patterning, suggesting that eye asymmetry is linked to mechanisms establishing primary laterality. Bilateral misexpression of a depolarizing channel mRNA affects primarily the right eye, revealing an additional functional asymmetry in the control of eye patterning by V(mem). The ATP-sensitive K(+) channel subunit transcript, SUR1, is asymmetrically expressed in the eye primordia, thus being a good candidate for the observed physiological asymmetries. Such subtle asymmetries are not only seen in the eye: consistent asymmetry was also observed in the migration of differentiated melanocytes on the left and right sides. These data suggest that even anatomically symmetrical structures may possess subtle but consistent laterality and interact with other developmental left-right patterning pathways.

Mapping ephemeral stream networks in desert environments using very-high-spatial-resolution multispectral remote sensing

DOE PAGES

Hamada, Yuki; O'Connor, Ben L.; Orr, Andrew B.; ...

2016-03-26

In this paper, understanding the spatial patterns of ephemeral streams is crucial for understanding how hydrologic processes influence the abundance and distribution of wildlife habitats in desert regions. Available methods for mapping ephemeral streams at the watershed scale typically underestimate the size of channel networks. Although remote sensing is an effective means of collecting data and obtaining information on large, inaccessible areas, conventional techniques for extracting channel features are not sufficient in regions that have small topographic gradients and subtle target-background spectral contrast. By using very high resolution multispectral imagery, we developed a new algorithm that applies landscape information tomore » map ephemeral channels in desert regions of the Southwestern United States where utility-scale solar energy development is occurring. Knowledge about landscape features and structures was integrated into the algorithm using a series of spectral transformation and spatial statistical operations to integrate information about landscape features and structures. The algorithm extracted ephemeral stream channels at a local scale, with the result that approximately 900% more ephemeral streams was identified than what were identified by using the U.S. Geological Survey’s National Hydrography Dataset. The accuracy of the algorithm in detecting channel areas was as high as 92%, and its accuracy in delineating channel center lines was 91% when compared to a subset of channel networks that were digitized by using the very high resolution imagery. Although the algorithm captured stream channels in desert landscapes across various channel sizes and forms, it often underestimated stream headwaters and channels obscured by bright soils and sparse vegetation. While further improvement is warranted, the algorithm provides an effective means of obtaining detailed information about ephemeral streams, and it could make a significant contribution toward improving the hydrological modelling of desert environments.« less

Mapping ephemeral stream networks in desert environments using very-high-spatial-resolution multispectral remote sensing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hamada, Yuki; O'Connor, Ben L.; Orr, Andrew B.

In this paper, understanding the spatial patterns of ephemeral streams is crucial for understanding how hydrologic processes influence the abundance and distribution of wildlife habitats in desert regions. Available methods for mapping ephemeral streams at the watershed scale typically underestimate the size of channel networks. Although remote sensing is an effective means of collecting data and obtaining information on large, inaccessible areas, conventional techniques for extracting channel features are not sufficient in regions that have small topographic gradients and subtle target-background spectral contrast. By using very high resolution multispectral imagery, we developed a new algorithm that applies landscape information tomore » map ephemeral channels in desert regions of the Southwestern United States where utility-scale solar energy development is occurring. Knowledge about landscape features and structures was integrated into the algorithm using a series of spectral transformation and spatial statistical operations to integrate information about landscape features and structures. The algorithm extracted ephemeral stream channels at a local scale, with the result that approximately 900% more ephemeral streams was identified than what were identified by using the U.S. Geological Survey’s National Hydrography Dataset. The accuracy of the algorithm in detecting channel areas was as high as 92%, and its accuracy in delineating channel center lines was 91% when compared to a subset of channel networks that were digitized by using the very high resolution imagery. Although the algorithm captured stream channels in desert landscapes across various channel sizes and forms, it often underestimated stream headwaters and channels obscured by bright soils and sparse vegetation. While further improvement is warranted, the algorithm provides an effective means of obtaining detailed information about ephemeral streams, and it could make a significant contribution toward improving the hydrological modelling of desert environments.« less

Small-scale structure and the Lyman-α forest baryon acoustic oscillation feature

NASA Astrophysics Data System (ADS)

Hirata, Christopher M.

2018-02-01

The baryon-acoustic oscillation (BAO) feature in the Lyman-α forest is a key probe of the cosmic expansion rate at redshifts z ˜ 2.5, well before dark energy is believed to have become significant. A key advantage of the BAO as a standard ruler is that it is a sharp feature and hence is more robust against broad-band systematic effects than other cosmological probes. However, if the Lyman-α forest transmission is sensitive to the initial streaming velocity of the baryons relative to the dark matter, then the BAO peak position can be shifted. Here we investigate this sensitivity using a suite of hydrodynamic simulations of small regions of the intergalactic medium with a range of box sizes and physics assumptions; each simulation starts from initial conditions at the kinematic decoupling era (z ˜ 1059), undergoes a discrete change from neutral gas to ionized gas thermal evolution at reionization (z ˜ 8), and is finally processed into a Lyman-α forest transmitted flux cube. Streaming velocities suppress small-scale structure, leading to less violent relaxation after reionization. The changes in the gas distribution and temperature-density relation at low redshift are more subtle, due to the convergent temperature evolution in the ionized phase. The change in the BAO scale is estimated to be of the order of 0.12 per cent at z = 2.5; some of the major uncertainties and avenues for future improvement are discussed. The predicted streaming velocity shift would be a subdominant but not negligible effect (of order 0.26σ) for the upcoming DESI Lyman-α forest survey, and exceeds the cosmic variance floor.

Tuning and Freezing Disorder in Photonic Crystals using Percolation Lithography

PubMed Central

Burgess, Ian B.; Abedzadeh, Navid; Kay, Theresa M.; Shneidman, Anna V.; Cranshaw, Derek J.; Lončar, Marko; Aizenberg, Joanna

2016-01-01

Although common in biological systems, synthetic self-assembly routes to complex 3D photonic structures with tailored degrees of disorder remain elusive. Here we show how liquids can be used to finely control disorder in porous 3D photonic crystals, leading to complex and hierarchical geometries. In these optofluidic crystals, dynamically tunable disorder is superimposed onto the periodic optical structure through partial wetting or evaporation. In both cases, macroscopic symmetry breaking is driven by subtle sub-wavelength variations in the pore geometry. These variations direct site-selective infiltration of liquids through capillary interactions. Incorporating cross-linkable resins into our liquids, we developed methods to freeze in place the filling patterns at arbitrary degrees of partial wetting and intermediate stages of drying. These percolation lithography techniques produced permanent photonic structures with adjustable disorder. By coupling strong changes in optical properties to subtle differences in fluid behavior, optofluidic crystals may also prove useful in rapid analysis of liquids. PMID:26790372

[3D FSPGR (fast spoiled gradient echo) magnetic resonance imaging in the diagnosis of focal cortical dysplasia in children].

PubMed

Alikhanov, A A; Sinitsyn, V E; Perepelova, E M; Mukhin, K Iu; Demushkina, A A; Omarova, M O; Piliia, S V

2001-01-01

Small dysplastic lesions of the cerebral cortex are often missed by conventional MRI methods. The identification of subtle structural abnormalities by traditional multiplanar rectilinear slices is often limited by the complex convolutional pattern of the brain. We used a method of FSPGR (fast spoiled gradient-echo) of three-dimensional MRI data that improves the anatomical display of the sulcal structure of the hemispheric convexities. It also reduces the asymmetric sampling of gray-white matter that may lead to false-positive results. We present 5 from 12 patients with dysplastic cortical lesions in whom conventional two-dimensional and three-dimensional MRI with multiplanar reformatting was initially considered normal. Subsequent studies using 3D FSPGR identified various types of focal cortical dysplasia in all. These results indicate that an increase in the detection of subtle focal dysplastic lesions may be accomplished when one improves the anatomical display of the brain sulcal structure by performing 3D FSPGR.

The structure and evolution of ancient impact basins on Mars

NASA Technical Reports Server (NTRS)

Schultz, P. H.; Schultz, R. A.; Rogers, J.

1982-01-01

It is pointed out that characteristic styles of degradation and modification of obvious Martian basins make it possible to recognize more subtle expressions. This approach is seen as providing not only additional basins to the existing inventory but also fundamental clues for initial impact basin structure and stratigraphy. It also reveals the long-lasting influence of basin formation on the crust of Mars in spite of extensive erosion and resurfacing. Consideration is given to five clear examples of modified impact basins, and regions around each that have undergone similar processes (fracturing, collapse, channeling) are delineated. These processes among the different basins are then compared, and similar zones of modification are correlated with concentric basin rings. Consideration is then given to the implications of these observations for current models of basin formation and to the role of impact basins in controlling regional tectonics. The results indicate that large multiring impact scars leave a major but sometimes subtle imprint on the geologic structure of stable crustal regions on Mars.

Medial Temporal Lobe Structures Contribute to On-Line Processing

ERIC Educational Resources Information Center

Warren, David

2009-01-01

For the last five decades, the medial temporal lobes have been generally understood to facilitate enduring representation of certain kinds of information. In particular, knowledge about the relations among items and concepts appears to rely on that region of the brain. Recent results suggest that those same structures also play a subtle role in…

The Rest of the C2 Iceberg

DTIC Science & Technology

2014-08-01

Iceberg Feature ones—another documented cognitive bias that is largely subconscious . A final opportunity lost by not having a forward geographic presence...leading to a subtle bias towards the tip-of-the-iceberg systems that most individuals have more famil- iarity with from their tactical backgrounds...as soon as possible to maintain career viability in a system biased more towards tactical achievement. Acknowledge That the Heart of Operational C2 Is

Mining and Querying Multimedia Data

DTIC Science & Technology

2011-09-29

able to capture more subtle spatial variations such as repetitiveness. Local feature descriptors such as SIFT [74] and SURF [12] have also been widely...empirically set to s = 90%, r = 50%, K = 20, where small variations lead to little perturbation of the output. The pseudo-code of the algorithm is...by constructing a three-layer graph based on clustering outputs, and executing a slight variation of random walk with restart algorithm. It provided

Characterization of 24-h cortisol release in obese and non-obese hyperandrogenic women.

PubMed

Miller, J E; Bray, M A; Faiman, C; Reyes, F I

1994-12-01

Excessive androgen output is a well-recognized feature of adrenocortical oversecretion in women with ovarian hyperandrogenism, or polycystic ovary disease (PCOD). However, evidence of a concomitant alteration of cortisol secretion is lacking even though obesity per se, a common clinical feature of PCOD, has been shown to be associated with cortisol oversecretion. To clarify whether a subtle alteration in cortisol secretion exists, a study of 24-h episodic cortisol release and post-prandial cortisol responses was undertaken in eight women with PCOD and eight normal women comprising equal numbers of obese and non-obese subjects. All four groups showed normal biphasic 24-h cortisol secretion profiles but cortisol pulse frequency was increased in the PCOD groups. Independently, both hyperandrogenism and obesity were associated with an accelerated cortisol clearance rate. These changes, together with normal or only slightly elevated 24-h cortisol integrated area under the curve, suggest an increased compensatory cortisol production in women with PCOD. Furthermore, subjects with PCOD and subjects with obesity showed different post-prandial cortisol responses to normal non-obese women. In conclusion, these subtle cortisol abnormalities may be a manifestation of altered central regulation of the hypothalamic-pituitary-adrenal axis and peripheral metabolic abnormalities, and may be linked to the pathophysiology of PCOD.

An analysis-by-synthesis approach to the estimation of vocal cord polyp features.

PubMed

Koizumi, T; Taniguchi, S; Itakura, F

1993-09-01

This paper deals with a new noninvasive method of estimating vocal cord polyp features through hoarse-voice analysis. A noteworthy feature of this method is that it enables us not only to discriminate hoarse voices caused by pathological vocal cords with a single golf-ball-like polyp from normal voices, but also to estimate polyp features such as the mass and dimension of polyp through the use of a novel model of pathological vocal cords which has been devised to simulate the subtle movement of the vocal cords. A synthetic hoarse voice produced with a hoarse-voice synthesizer is compared with a natural hoarse voice caused by the vocal cord polyp in terms of a distance measure and the polyp features are estimated by minimizing the distance measure. Some estimates of polyp dimension that have been obtained by applying this procedure to hoarse voices are found to compare favorably with actual polyp dimensions, demonstrating that the procedure is effective for estimating the features of golf-ball-like vocal cord polyps.

Ba3M Ir2O9 hexagonal perovskites in the light of spin-orbit coupling and local structural distortions

NASA Astrophysics Data System (ADS)

Nag, Abhishek; Bhowal, Sayantika; Bert, F.; Hillier, A. D.; Itoh, M.; Carlomagno, Ilaria; Meneghini, C.; Sarkar, T.; Mathieu, R.; Dasgupta, I.; Ray, Sugata

2018-02-01

Spin-orbit coupling (SOC) is found to be crucial for understanding the magnetic and electronic properties of 5 d transition metal oxides. In 5 d systems, with Ir5 + ions, where ideally a nonmagnetic J =0 ground state is expected to be stabilized in the presence of strong SOC, often spontaneous moments are generated due to hopping induced superexchange. This effect is more pronounced when the Ir atoms are close by, as in systems with Ir2O9 dimers in 6 H Ba3M Ir2O9 compounds where magnetism is an outcome of complex Ir-O-Ir exchange paths, and is strongly influenced by the presence of local distortions. We find that subtle variations in the local structure of Ba3M Ir2O9 (M = Mg, Sr, and Ca) lead to markedly different magnetic properties. While SOC plays a pivotal role in explaining the insulating ground states of these systems, it is seen that Ba3MgIr2O9 , having a P 63 /m m c symmetry, does not order down to low temperature despite having antiferromagnetic exchange interactions, while Ba3CaIr2O9 shows weak dimer-like features and stabilizes in C 2 /c' magnetic configuration with no net moment, and Ba3SrIr2O9 possesses a ground state corresponding to the magnetic space group C 2'/c' and exhibits ferromagnet-like features.

Hidden flexion injury of the cervical spine.

PubMed

Webb, J K; Broughton, R B; McSweeney, T; Park, W M

1976-08-01

This paper describes seven patients who developed late vertebral deformity after flexion injuries of the cervical spine. In four the clinical and radiological features were subtle and because the patients walked into an emergency department the severity of the injury was not initially appreciated. Certain specific clinical and radiological features of flexion injury are described and emphasis is placed on the importance of correct management. A radiological tetrad is described which should alert the surgeon to the possibility of damage to the posterior interspinous complex of the cervical spine and so lead to further radiological investigations. Despite the frequency of flexion injuries the alarming complications described in this paper are rare.

On the detection of adobe buried archaeological structures using multiscale remote sensing techniques : Piramide Naranja in Cahuachi (Peru)

NASA Astrophysics Data System (ADS)

Masini, N.; Rizzo, E.; Lasaponara, R.; Orefici, G.

2009-04-01

The detection of buried adobe structures is a crucial issue for the remote sensing (ground, aerial and satellite) applied to archaeology for the widespread of sun-dried earth as building material in several ancient civilizations in Central and Southern America, Middle East and North Africa. Moreover it is complex, due to the subtle contrast existing between the archaeological features and the surrounding, especially in arid setting, as in the case of the well know Nazca Ceremonial Centre of Cahuachi, located in the desert of Nazca (Southern Peru) . During the last two decades of excavations adobe monuments dating back from the 6th century B.C. to the 4th century A.D have been highlighted by the Centro de Estudios Arqueológicos Precolombinos (CEAP), an italian-peruvian mission directed by Giuseppe Orefici. Actually, the archaeologists are excavating and restoring the core of the Ceremonial centre where is located a great pyramid (kown as Gran Piramide). Beginning from 2007 the two institutes of CNR, IMAA and IBAM, have been involved by CEAP, in order to provide a scientific and technological support for the archaeological research. Therefore, a multi-scale approach based on the integration of aerial and satellite remote sensing with geophysical techniques was employed in order to provide data useful for archaeological excavations. The abstract refers to the last investigations performed on a mound, known as "Piramide Naranja", during the 2008. The processing of an aerial imagery time series and two QuickBird satellite images acquired in 2002 and 2005, allowed for identifying some features related to shallow and buried structures. Such features were verified by means of geophysical prospections, performed by using the magnetometric method which observed changes in the magnetic field within the first few metres beneath the subsurface detecting buried walls and anomalies linked to ceramic deposits referable to possible tombs. Finally, the integration of all data acquired by the different remote sensing techniques allowed for spatially characterizing the archaeological features, thus providing important information for the planning of the next archaeological campaign scheduled on July 2009

Deriving quantitative dynamics information for proteins and RNAs using ROTDIF with a graphical user interface.

PubMed

Berlin, Konstantin; Longhini, Andrew; Dayie, T Kwaku; Fushman, David

2013-12-01

To facilitate rigorous analysis of molecular motions in proteins, DNA, and RNA, we present a new version of ROTDIF, a program for determining the overall rotational diffusion tensor from single- or multiple-field nuclear magnetic resonance relaxation data. We introduce four major features that expand the program's versatility and usability. The first feature is the ability to analyze, separately or together, (13)C and/or (15)N relaxation data collected at a single or multiple fields. A significant improvement in the accuracy compared to direct analysis of R2/R1 ratios, especially critical for analysis of (13)C relaxation data, is achieved by subtracting high-frequency contributions to relaxation rates. The second new feature is an improved method for computing the rotational diffusion tensor in the presence of biased errors, such as large conformational exchange contributions, that significantly enhances the accuracy of the computation. The third new feature is the integration of the domain alignment and docking module for relaxation-based structure determination of multi-domain systems. Finally, to improve accessibility to all the program features, we introduced a graphical user interface that simplifies and speeds up the analysis of the data. Written in Java, the new ROTDIF can run on virtually any computer platform. In addition, the new ROTDIF achieves an order of magnitude speedup over the previous version by implementing a more efficient deterministic minimization algorithm. We not only demonstrate the improvement in accuracy and speed of the new algorithm for synthetic and experimental (13)C and (15)N relaxation data for several proteins and nucleic acids, but also show that careful analysis required especially for characterizing RNA dynamics allowed us to uncover subtle conformational changes in RNA as a function of temperature that were opaque to previous analysis.

Microgravity

NASA Image and Video Library

1997-01-12

1 mm histone octamer crystal grown on STS-81. A very dynamic structure which functions in many aspects of gene regulation from control of gene activity to the more subtle mechanisms of genetic imprinting. Principle Investigator is Dan Carter of New Century Pharmaceuticals.

Spectral reflectance and emissivity features of broad leaf plants: Prospects for remote sensing in the thermal infrared (8.0-14.0 μm)

USGS Publications Warehouse

Ribeiro da Luz, Beatriz; Crowley, James K.

2007-01-01

In contrast to visible and short-wave infrared data, thermal infrared spectra of broad leaf plants show considerable spectral diversity, suggesting that such data eventually could be utilized to map vegetation composition. However, remotely measuring the subtle emissivity features of leaves still presents major challenges. To be successful, sensors operating in the 8–14 μm atmospheric window must have high signal-to-noise and a small enough instantaneous field of view to allow measurements of only a few leaf surfaces. Methods for atmospheric compensation, temperature–emissivity separation, and spectral feature analysis also will need to be refined to allow the recognition, and perhaps, exploitation of leaf thermal infrared spectral properties.

Combined strong anion-exchange HPLC and PAGE approach for the purification of heparan sulphate oligosaccharides.

PubMed

Vivès, R R; Goodger, S; Pye, D A

2001-02-15

Heparan sulphates are highly sulphated linear polysaccharides involved in many cellular functions. Their biological properties stem from their ability to interact with a wide range of proteins. An increasing number of studies, using heparan sulphate-derived oligosaccharides, suggest that specific structural features within the polysaccharide are responsible for ligand recognition and regulation. In the present study, we show that strong anion-exchange HPLC alone, a commonly used technique for purification of heparan sulphate-derived oligosaccharides, may not permit the isolation of highly pure heparan sulphate oligosaccharide species. This was determined by PAGE analysis of hexa-, octa- and decasaccharide samples deemed to be pure by strong anion-exchange HPLC. In addition, subtle differences in the positioning of sulphate groups within heparan sulphate hexasaccharides were impossible to detect by strong anion-exchange HPLC. PAGE analysis on the other hand afforded excellent resolution of these structural isomers. The precise positioning of specific sulphate groups has been implicated in determining the specificity of heparan sulphate interactions and biological activities; hence, the purification of oligosaccharide species that differ in this way becomes an important issue. In this study, we have used strong anion-exchange HPLC and PAGE techniques to allow production of the homogeneous heparan sulphate oligosaccharide species that will be required for the detailed study of structure/activity relationships.

Spatial analysis of temperature (BHT/DST) data and consequences for heat-flow determination in sedimentary basins

USGS Publications Warehouse

Forster, A.; Merriam, D.F.; Davis, J.C.

1997-01-01

Large numbers of bottom-hole temperatures (BHTs) and temperatures measured during drill-stem tests (DSTs) are available in areas explored for hydrocarbons, but their usefulness for estimating geothermal gradients and heat-flow density is limited. We investigated a large data set of BHT and DST measurements taken in boreholes in the American Midcontinent, a geologically uniform stable cratonic area, and propose an empirical correction for BHTs based on relationships between BHTs, DSTs, and thermal logs. This empirical correction is compared with similar approaches determined for other areas. The data were analyzed by multivariate statistics prior to the BHT correction to identify anomalous measurements and quantify external influences. Spatial patterns in temperature measurements for major stratigraphic units outline relations to regional structure. Comparision of temperature and structure trend-surface residuals reveals a relationship between temperature highs and local structure highs. The anticlines, developed by continuous but intermittent movement of basement fault blocks in the Late Paleozoic, are subtle features having closures of 10-30 m and contain relatively small hydrocarbon reservoirs. The temperature anomalies of the order of 5-7 ??C may reflect fluids moving upward along fractures and faults, rather than changes in thermal conductivity resulting from different pore fluids. ?? Springer-Verlag 1997.

Spatial analysis of temperature (BHT/DST) data and consequences for heat-flow determination in sedimentary basins

USGS Publications Warehouse

Forster, A.; Merriam, D.F.; Davis, J.C.

1997-01-01

Large numbers of bottom-hole temperatures (BHTs) and temperatures measured during drill-stem tests (DSTs) are available in areas explored for hydrocarbons, but their usefulness for estimating geothermal gradients and heat-flow density is limited. We investigated a large data set of BHT and DST measurements taken in boreholes in the American Midcontinent, a geologically uniform stable cratonic area, and propose an empirical correction for BHTs based on relationships between BHTs, DSTs, and thermal logs. This empirical correction is compared with similar approaches determined for other areas. The data were analyzed by multivariate statistics prior to the BHT correction to identify anomalous measurements and quantify external influences. Spatial patterns in temperature measurements for major stratigraphic units outline relations to regional structure. Comparision of temperature and structure trend-surface residuals reveals a relationship between temperature highs and local structure highs. The anticlines, developed by continuous but intermittent movement of basement fault blocks in the Late Paleozoic, are subtle features having closures of 10-30 m and contain relatively small hydrocarbon reservoirs. The temperature anomalies of the order of 5-7??C may reflect fluids moving upward along fractures and faults, rather than changes in thermal conductivity resulting from different pore fluids.

Diversity of Secondary Structure in Catalytic Peptides with β-Turn-Biased Sequences

PubMed Central

2016-01-01

X-ray crystallography has been applied to the structural analysis of a series of tetrapeptides that were previously assessed for catalytic activity in an atroposelective bromination reaction. Common to the series is a central Pro-Xaa sequence, where Pro is either l- or d-proline, which was chosen to favor nucleation of canonical β-turn secondary structures. Crystallographic analysis of 35 different peptide sequences revealed a range of conformational states. The observed differences appear not only in cases where the Pro-Xaa loop-region is altered, but also when seemingly subtle alterations to the flanking residues are introduced. In many instances, distinct conformers of the same sequence were observed, either as symmetry-independent molecules within the same unit cell or as polymorphs. Computational studies using DFT provided additional insight into the analysis of solid-state structural features. Select X-ray crystal structures were compared to the corresponding solution structures derived from measured proton chemical shifts, 3J-values, and 1H–1H-NOESY contacts. These findings imply that the conformational space available to simple peptide-based catalysts is more diverse than precedent might suggest. The direct observation of multiple ground state conformations for peptides of this family, as well as the dynamic processes associated with conformational equilibria, underscore not only the challenge of designing peptide-based catalysts, but also the difficulty in predicting their accessible transition states. These findings implicate the advantages of low-barrier interconversions between conformations of peptide-based catalysts for multistep, enantioselective reactions. PMID:28029251

Print Advertisements for Alzheimer’s Disease Drugs: Informational and Transformational Features

PubMed Central

Gooblar, Jonathan; Carpenter, Brian D.

2014-01-01

Purpose We examined print advertisements for Alzheimer’s disease drugs published in journals and magazines between January 2008 and February 2012, using an informational versus transformational theoretical framework to identify objective and persuasive features. Methods In 29 unique advertisements, we used qualitative methods to code and interpret identifying information, charts, benefit and side effect language, and persuasive appeals embedded in graphics and narratives. Results Most elements contained a mixture of informational and transformational features. Charts were used infrequently, but when they did appear the accompanying text often exaggerated the data. Benefit statements covered an array of symptoms, drug properties, and caregiver issues. Side effect statements often used positive persuasive appeals. Graphics and narrative features emphasized positive emotions and outcomes. Implications We found subtle and sophisticated attempts both to educate and to persuade readers. It is important for consumers and prescribing physicians to read print advertisements critically so that they can make informed treatment choices. PMID:23687184

Print advertisements for Alzheimer's disease drugs: informational and transformational features.

PubMed

Gooblar, Jonathan; Carpenter, Brian D

2013-06-01

We examined print advertisements for Alzheimer's disease drugs published in journals and magazines between January 2008 and February 2012, using an informational versus transformational theoretical framework to identify objective and persuasive features. In 29 unique advertisements, we used qualitative methods to code and interpret identifying information, charts, benefit and side effect language, and persuasive appeals embedded in graphics and narratives. Most elements contained a mixture of informational and transformational features. Charts were used infrequently, but when they did appear the accompanying text often exaggerated the data. Benefit statements covered an array of symptoms, drug properties, and caregiver issues. Side effect statements often used positive persuasive appeals. Graphics and narrative features emphasized positive emotions and outcomes. We found subtle and sophisticated attempts both to educate and to persuade readers. It is important for consumers and prescribing physicians to read print advertisements critically so that they can make informed treatment choices.

Shaded Relief of Rio Sao Francisco, Brazil

NASA Image and Video Library

2000-02-14

This topographic image acquired by SRTM shows an area south of the Sao Francisco River in Brazil. The scrub forest terrain shows relief of about 400 meters (1300 feet). Areas such as these are difficult to map by traditional methods because of frequent cloud cover and local inaccessibility. This region has little topographic relief, but even subtle changes in topography have far-reaching effects on regional ecosystems. The image covers an area of 57 km x 79 km and represents one quarter of the 225 km SRTM swath. Colors range from dark blue at water level to white and brown at hill tops. The terrain features that are clearly visible in this image include tributaries of the Sao Francisco, the dark-blue branch-like features visible from top right to bottom left, and on the left edge of the image, and hills rising up from the valley floor. The San Francisco River is a major source of water for irrigation and hydroelectric power. Mapping such regions will allow scientists to better understand the relationships between flooding cycles, forestation and human influences on ecosystems. This shaded relief image was generated using topographic data from the Shuttle Radar Topography Mission. A computer-generated artificial light source illuminates the elevation data to produce a pattern of light and shadows. Slopes facing the light appear bright, while those facing away are shaded. On flatter surfaces, the pattern of light and shadows can reveal subtle features in the terrain. Shaded relief maps are commonly used in applications such as geologic mapping and land use planning. http://photojournal.jpl.nasa.gov/catalog/PIA02700

Cocaine Exposure Is Associated with Subtle Compromises of Infants' and Mothers' Social-Emotional Behavior and Dyadic Features of Their Interaction in the Face-to-Face Still-Face Paradigm

ERIC Educational Resources Information Center

Tronick, E. Z.; Messinger, D. S.; Weinberg, M. K.; Lester, B. M.; LaGasse, L.; Seifer, R.; Bauer, C. R.; Shankaran, S.; Bada, H.; Wright, L. L.; Poole, K.; Liu, J.

2005-01-01

Prenatal cocaine and opiate exposure are thought to subtly compromise social and emotional development. The authors observed a large sample of 236 cocaine-exposed and 459 nonexposed infants (49 were opiate exposed and 646 nonexposed) with their mothers in the face-to-face still-face paradigm. Infant and maternal behaviors were microanalytically…

Photoelectron spectroscopy of the bis(dithiolene) anions [M(mnt)2]n- (M = Fe - Zn; n = 1, 2): changes in electronic structure with variation of metal center and with oxidation.

PubMed

Waters, Tom; Wang, Xue-Bin; Woo, Hin-Koon; Wang, Lai-Sheng

2006-07-24

A detailed understanding of the electronic structures of transition metal bis(dithiolene) centers is important in the context of their interesting redox, magnetic, and optical properties. The electronic structures of the series [M(mnt)2]n- (M = Fe - Zn; mnt = 1,2-S2C2(CN)2; n = 1, 2) were examined by a combination of photodetachment photoelectron spectroscopy and density functional theory calculations, providing insights into changes in electronic structure with variation of the metal center and with oxidation. Significant changes were observed for the dianions [M(mnt)2]2- due to stabilization of the metal 3d levels from Fe to Zn and the transition from square-planar to tetrahedral coordination about the metal center (Fe-Ni, D(2h) --> Cu D2 --> Zn, D(2d). Changes with oxidation from [M(mnt)2]2- to [M(mnt)2]1- were largely dependent on the nature of the redox-active orbital in the couple [M(mnt)2](2-/1-). In particular, the first detachment feature for [Fe(mnt)2]2- originated from a metal-based orbital (Fe(II) --> Fe(III)) while that for [Fe(mnt)2]1- originated from a ligand-based orbital, a consequence of stabilization of Fe 3d levels in the latter. In contrast, the first detachment feature for both of [Ni(mnt)2]2- and [Ni(mnt)2]1- originated from the same ligand-based orbital in both cases, a result of occupied Ni 3d levels being stabilized relative those of Fe 3d and occurring below the highest energy occupied ligand-based orbital for both of [Ni(mnt)2]2- and [Ni(mnt)2]1- . The combined data illustrate the subtle interplay between metal- and ligand-based redox chemistry in these species and demonstrate changes in their electronic structures with variation of metal center, oxidation, and coordination geometry.

Extending Halogen-based Medicinal Chemistry to Proteins

PubMed Central

El Hage, Krystel; Pandyarajan, Vijay; Phillips, Nelson B.; Smith, Brian J.; Menting, John G.; Whittaker, Jonathan; Lawrence, Michael C.; Meuwly, Markus; Weiss, Michael A.

2016-01-01

Insulin, a protein critical for metabolic homeostasis, provides a classical model for protein design with application to human health. Recent efforts to improve its pharmaceutical formulation demonstrated that iodination of a conserved tyrosine (TyrB26) enhances key properties of a rapid-acting clinical analog. Moreover, the broad utility of halogens in medicinal chemistry has motivated the use of hybrid quantum- and molecular-mechanical methods to study proteins. Here, we (i) undertook quantitative atomistic simulations of 3-[iodo-TyrB26]insulin to predict its structural features, and (ii) tested these predictions by X-ray crystallography. Using an electrostatic model of the modified aromatic ring based on quantum chemistry, the calculations suggested that the analog, as a dimer and hexamer, exhibits subtle differences in aromatic-aromatic interactions at the dimer interface. Aromatic rings (TyrB16, PheB24, PheB25, 3-I-TyrB26, and their symmetry-related mates) at this interface adjust to enable packing of the hydrophobic iodine atoms within the core of each monomer. Strikingly, these features were observed in the crystal structure of a 3-[iodo-TyrB26]insulin analog (determined as an R6 zinc hexamer). Given that residues B24–B30 detach from the core on receptor binding, the environment of 3-I-TyrB26 in a receptor complex must differ from that in the free hormone. Based on the recent structure of a “micro-receptor” complex, we predict that 3-I-TyrB26 engages the receptor via directional halogen bonding and halogen-directed hydrogen bonding as follows: favorable electrostatic interactions exploiting, respectively, the halogen's electron-deficient σ-hole and electronegative equatorial band. Inspired by quantum chemistry and molecular dynamics, such “halogen engineering” promises to extend principles of medicinal chemistry to proteins. PMID:27875310

Electronic structures of WAlO(y) and WAlO(y)(-) (y = 2-4) determined by anion photoelectron spectroscopy and density functional theory calculations.

PubMed

Mann, Jennifer E; Waller, Sarah E; Jarrold, Caroline Chick

2012-07-28

The anion photoelectron spectra of WAlO(y)(-) (y = 2-4) are presented and assigned based on results of density functional theory calculations. The WAlO(2)(-) and WAlO(3)(-) spectra are both broad, with partially resolved vibrational structure. In contrast, the WAlO(4)(-) spectrum features well-resolved vibrational structure with contributions from three modes. There is reasonable agreement between experiment and theory for all oxides, and calculations are in particular validated by the near perfect agreement between the WAlO(4)(-) photoelectron spectrum and a Franck-Condon simulation based on computationally determined spectroscopic parameters. The structures determined from this study suggest strong preferential W-O bond formation, and ionic bonding between Al(+) and WO(y)(-2) for all anions. Neutral species are similarly ionic, with WAlO(2) and WAlO(3) having electronic structure that suggests Al(+) ionically bound to WO(y)(-) and WAlO(4) being described as Al(+2) ionically bound to WO(4)(-2). The doubly-occupied 3sp hybrid orbital localized on the Al center is energetically situated between the bonding O-local molecular orbitals and the anti- or non-bonding W-local molecular orbitals. The structures determined in this study are very similar to structures recently determined for the analogous MoAlO(y)(-)/MoAlO(y) cluster series, with subtle differences found in the electronic structures [S. E. Waller, J. E. Mann, E. Hossain, M. Troyer, and C. C. Jarrold, J. Chem. Phys. 137, 024302 (2012)].

http://www.nasa.gov/image-feature/goddard/hubble-spots-the-layers-of-ngc-3923

NASA Image and Video Library

2015-05-15

The glowing object in this Hubble Space Telescope image is an elliptical galaxy called NGC 3923. It is located over 90 million light-years away in the constellation of Hydra. NGC 3923 is an example of a shell galaxy where the stars in its halo are arranged in layers. Finding concentric shells of stars enclosing a galaxy is quite common and is observed in many elliptical galaxies. In fact, every tenth elliptical galaxy exhibits this onion-like structure, which has never been observed in spiral galaxies. The shell-like structures are thought to develop as a consequence of galactic cannibalism, when a larger galaxy ingests a smaller companion. As the two centers approach, they initially oscillate about a common center, and this oscillation ripples outwards forming the shells of stars just as ripples on a pond spread when the surface is disturbed. NGC 3923 has over twenty shells, with only a few of the outer ones visible in this image, and its shells are much more subtle than those of other shell galaxies. The shells of this galaxy are also interestingly symmetrical, while other shell galaxies are more skewed. Credit: ESA/Hubble & NASA

Site-specific incorporation of uranyl carbonate species at the calcite surface

NASA Astrophysics Data System (ADS)

Reeder, Richard J.; Elzinga, Evert J.; Tait, C. Drew; Rector, K. D.; Donohoe, Robert J.; Morris, David E.

2004-12-01

Spatially resolved luminescence spectra from U(VI) co-precipitated at the (101¯4) growth surface of synthetic calcite single crystals confirm heterogeneous incorporation corresponding to the distribution of structurally non-equivalent steps composing the vicinal surfaces of spiral growth hillocks. Spectral structure from U(VI) luminescence at the "-" vicinal regions and featureless, weak luminescence at the "+" vicinal regions are consistent with previously reported observations of enrichment at the former sites during calcite growth. Luminescence spectra differ between the non-equivalent regions of the crystal, with the spectral features from the "-" vicinal region corresponding to those observed in bulk calcite samples. Subtle spectral shifts are observed from U(VI) co-precipitated with microcrystalline calcite synthesized by a different method, and all of the U(VI)-calcite sample spectra differ significantly from that of U(VI) co-precipitated with aragonite. The step-selective incorporation of U(VI) can be explained by a proposed model in which the allowed orientation for adsorption of the dominant calcium uranyl triscarbonate species is controlled by the atomic arrangement at step edges. Differences in the tilt angles of carbonate groups between non-equivalent growth steps favor adsorption of the calcium uranyl triscarbonate species at "-" steps, as observed in experiments.

Probing Transient Valence Orbital Changes with Picosecond Valence-to-Core X-ray Emission Spectroscopy

DOE PAGES

March, Anne Marie; Assefa, Tadesse A.; Boemer, Christina; ...

2017-01-17

Here we probe the dynamics of valence electrons in photoexcited [Fe(terpy) 2] 2+ in solution to gain deeper insight into the Fe-ligand bond changes. We use hard X-ray emission spectroscopy (XES), which combines element specificity and high penetration with sensitivity to orbital structure, making it a powerful technique for molecular studies in a wide variety of environments. A picosecond-time-resolved measurement of the complete Is X-ray emission spectrum captures the transient photoinduced changes and includes the weak valence-to-core (vtc) emission lines that correspond to transitions from occupied valence orbitals to the nascent core-hole. Vtc-XES offers particular insight into the molecular orbitalsmore » directly involved in the light-driven dynamics; a change in the metal-ligand orbital overlap results in an intensity reduction and a blue energy shift in agreement with our theoretical calculations and more subtle features at the highest energies reflect changes in the frontier orbital populations.« less

Probing Transient Valence Orbital Changes with Picosecond Valence-to-Core X-ray Emission Spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

March, Anne Marie; Assefa, Tadesse A.; Boemer, Christina

Here we probe the dynamics of valence electrons in photoexcited [Fe(terpy) 2] 2+ in solution to gain deeper insight into the Fe-ligand bond changes. We use hard X-ray emission spectroscopy (XES), which combines element specificity and high penetration with sensitivity to orbital structure, making it a powerful technique for molecular studies in a wide variety of environments. A picosecond-time-resolved measurement of the complete Is X-ray emission spectrum captures the transient photoinduced changes and includes the weak valence-to-core (vtc) emission lines that correspond to transitions from occupied valence orbitals to the nascent core-hole. Vtc-XES offers particular insight into the molecular orbitalsmore » directly involved in the light-driven dynamics; a change in the metal-ligand orbital overlap results in an intensity reduction and a blue energy shift in agreement with our theoretical calculations and more subtle features at the highest energies reflect changes in the frontier orbital populations.« less

Asymmetry of the Brain: Development and Implications.

PubMed

Duboc, Véronique; Dufourcq, Pascale; Blader, Patrick; Roussigné, Myriam

2015-01-01

Although the left and right hemispheres of our brains develop with a high degree of symmetry at both the anatomical and functional levels, it has become clear that subtle structural differences exist between the two sides and that each is dominant in processing specific cognitive tasks. As the result of evolutionary conservation or convergence, lateralization of the brain is found in both vertebrates and invertebrates, suggesting that it provides significant fitness for animal life. This widespread feature of hemispheric specialization has allowed the emergence of model systems to study its development and, in some cases, to link anatomical asymmetries to brain function and behavior. Here, we present some of what is known about brain asymmetry in humans and model organisms as well as what is known about the impact of environmental and genetic factors on brain asymmetry development. We specifically highlight the progress made in understanding the development of epithalamic asymmetries in zebrafish and how this model provides an exciting opportunity to address brain asymmetry at different levels of complexity.

Neural mechanisms underlying sensitivity to reverse-phi motion in the fly

PubMed Central

Meier, Matthias; Serbe, Etienne; Eichner, Hubert; Borst, Alexander

2017-01-01

Optical illusions provide powerful tools for mapping the algorithms and circuits that underlie visual processing, revealing structure through atypical function. Of particular note in the study of motion detection has been the reverse-phi illusion. When contrast reversals accompany discrete movement, detected direction tends to invert. This occurs across a wide range of organisms, spanning humans and invertebrates. Here, we map an algorithmic account of the phenomenon onto neural circuitry in the fruit fly Drosophila melanogaster. Through targeted silencing experiments in tethered walking flies as well as electrophysiology and calcium imaging, we demonstrate that ON- or OFF-selective local motion detector cells T4 and T5 are sensitive to certain interactions between ON and OFF. A biologically plausible detector model accounts for subtle features of this particular form of illusory motion reversal, like the re-inversion of turning responses occurring at extreme stimulus velocities. In light of comparable circuit architecture in the mammalian retina, we suggest that similar mechanisms may apply even to human psychophysics. PMID:29261684

Neural mechanisms underlying sensitivity to reverse-phi motion in the fly.

PubMed

Leonhardt, Aljoscha; Meier, Matthias; Serbe, Etienne; Eichner, Hubert; Borst, Alexander

2017-01-01

Optical illusions provide powerful tools for mapping the algorithms and circuits that underlie visual processing, revealing structure through atypical function. Of particular note in the study of motion detection has been the reverse-phi illusion. When contrast reversals accompany discrete movement, detected direction tends to invert. This occurs across a wide range of organisms, spanning humans and invertebrates. Here, we map an algorithmic account of the phenomenon onto neural circuitry in the fruit fly Drosophila melanogaster. Through targeted silencing experiments in tethered walking flies as well as electrophysiology and calcium imaging, we demonstrate that ON- or OFF-selective local motion detector cells T4 and T5 are sensitive to certain interactions between ON and OFF. A biologically plausible detector model accounts for subtle features of this particular form of illusory motion reversal, like the re-inversion of turning responses occurring at extreme stimulus velocities. In light of comparable circuit architecture in the mammalian retina, we suggest that similar mechanisms may apply even to human psychophysics.

Protecting group and switchable pore-discriminating adsorption properties of a hydrophilic-hydrophobic metal-organic framework.

PubMed

Mohideen, M Infas H; Xiao, Bo; Wheatley, Paul S; McKinlay, Alistair C; Li, Yang; Slawin, Alexandra M Z; Aldous, David W; Cessford, Naomi F; Düren, Tina; Zhao, Xuebo; Gill, Rachel; Thomas, K Mark; Griffin, John M; Ashbrook, Sharon E; Morris, Russell E

2011-04-01

Formed by linking metals or metal clusters through organic linkers, metal-organic frameworks are a class of solids with structural and chemical properties that mark them out as candidates for many emerging gas storage, separation, catalysis and biomedical applications. Important features of these materials include their high porosity and their flexibility in response to chemical or physical stimuli. Here, a copper-based metal-organic framework has been prepared in which the starting linker (benzene-1,3,5-tricarboxylic acid) undergoes selective monoesterification during synthesis to produce a solid with two different channel systems, lined by hydrophilic and hydrophobic surfaces, respectively. The material reacts differently to gases or vapours of dissimilar chemistry, some stimulating subtle framework flexibility or showing kinetic adsorption effects. Adsorption can be switched between the two channels by judicious choice of the conditions. The monoesterified linker is recoverable in quantitative yield, demonstrating possible uses of metal-organic frameworks in molecular synthetic chemistry as 'protecting groups' to accomplish selective transformations that are difficult using standard chemistry techniques.

Impacts on the Hubble Space Telescope Wide Field and Planetary Camera 2: Microanalysis and Recognition of Micrometeoroid Compositions

NASA Technical Reports Server (NTRS)

Kearsley, A. T.; Ross, D. K.; Anz-Meador, P.; Liou, J. C.; Opiela, J.; Grime, G. W.; Webb, R. P.; Jeynes, C.; Palitsin, V. V.; Colaux, J. L.;

AN OVERVIEW OF COMPUTATIONAL LIFE SCIENCE DATABASES & EXCHANGE FORMATS OF RELEVANCE TO CHEMICAL BIOLOGY RESEARCH

PubMed Central

Hall, Aaron Smalter; Shan, Yunfeng; Lushington, Gerald; Visvanathan, Mahesh

2016-01-01

Databases and exchange formats describing biological entities such as chemicals and proteins, along with their relationships, are a critical component of research in life sciences disciplines, including chemical biology wherein small information about small molecule properties converges with cellular and molecular biology. Databases for storing biological entities are growing not only in size, but also in type, with many similarities between them and often subtle differences. The data formats available to describe and exchange these entities are numerous as well. In general, each format is optimized for a particular purpose or database, and hence some understanding of these formats is required when choosing one for research purposes. This paper reviews a selection of different databases and data formats with the goal of summarizing their purposes, features, and limitations. Databases are reviewed under the categories of 1) protein interactions, 2) metabolic pathways, 3) chemical interactions, and 4) drug discovery. Representation formats will be discussed according to those describing chemical structures, and those describing genomic/proteomic entities. PMID:22934944

Digital Compositing Techniques for Coronal Imaging (Invited review)

NASA Astrophysics Data System (ADS)

Espenak, F.

2000-04-01

The solar corona exhibits a huge range in brightness which cannot be captured in any single photographic exposure. Short exposures show the bright inner corona and prominences, while long exposures reveal faint details in equatorial streamers and polar brushes. For many years, radial gradient filters and other analog techniques have been used to compress the corona's dynamic range in order to study its morphology. Such techniques demand perfect pointing and tracking during the eclipse, and can be difficult to calibrate. In the past decade, the speed, memory and hard disk capacity of personal computers have rapidly increased as prices continue to drop. It is now possible to perform sophisticated image processing of eclipse photographs on commercially available CPU's. Software programs such as Adobe Photoshop permit combining multiple eclipse photographs into a composite image which compresses the corona's dynamic range and can reveal subtle features and structures. Algorithms and digital techniques used for processing 1998 eclipse photographs will be discussed which are equally applicable to the recent eclipse of 1999 August 11.

Flexible hemispheric microarrays of highly pressure-sensitive sensors based on breath figure method.

PubMed

Wang, Zhihui; Zhang, Ling; Liu, Jin; Jiang, Hao; Li, Chunzhong

2018-05-30

Recently, flexible pressure sensors featuring high sensitivity, broad sensing range and real-time detection have aroused great attention owing to their crucial role in the development of artificial intelligent devices and healthcare systems. Herein, highly sensitive pressure sensors based on hemisphere-microarray flexible substrates are fabricated via inversely templating honeycomb structures deriving from a facile and static breath figure process. The interlocked and subtle microstructures greatly improve the sensing characteristics and compressibility of the as-prepared pressure sensor, endowing it a sensitivity as high as 196 kPa-1 and a wide pressure sensing range (0-100 kPa), as well as other superior performance, including a lower detection limit of 0.5 Pa, fast response time (<26 ms) and high reversibility (>10 000 cycles). Based on the outstanding sensing performance, the potential capability of our pressure sensor in capturing physiological information and recognizing speech signals has been demonstrated, indicating promising application in wearable and intelligent electronics.

Voice and endocrinology

PubMed Central

Hari Kumar, K. V. S.; Garg, Anurag; Ajai Chandra, N. S.; Singh, S. P.; Datta, Rakesh

2016-01-01

Voice is one of the advanced features of natural evolution that differentiates human beings from other primates. The human voice is capable of conveying the thoughts into spoken words along with a subtle emotion to the tone. This extraordinary character of the voice in expressing multiple emotions is the gift of God to the human beings and helps in effective interpersonal communication. Voice generation involves close interaction between cerebral signals and the peripheral apparatus consisting of the larynx, vocal cords, and trachea. The human voice is susceptible to the hormonal changes throughout life right from the puberty until senescence. Thyroid, gonadal and growth hormones have tremendous impact on the structure and function of the vocal apparatus. The alteration of voice is observed even in physiological states such as puberty and menstruation. Astute clinical observers make out the changes in the voice and refer the patients for endocrine evaluation. In this review, we shall discuss the hormonal influence on the voice apparatus in normal and endocrine disorders. PMID:27730065

Multispectral image enhancement for H&E stained pathological tissue specimens

NASA Astrophysics Data System (ADS)

Bautista, Pinky A.; Abe, Tokiya; Yamaguchi, Masahiro; Ohyama, Nagaaki; Yagi, Yukako

2008-03-01

The presence of a liver disease such as cirrhosis can be determined by examining the proliferation of collagen fiber from a tissue slide stained with special stain such as the Masson's trichrome(MT) stain. Collagen fiber and smooth muscle, which are both stained the same in an H&E stained slide, are stained blue and pink respectively in an MT-stained slide. In this paper we show that with multispectral imaging the difference between collagen fiber and smooth muscle can be visualized even from an H&E stained image. In the method M KL bases are derived using the spectral data of those H&E stained tissue components which can be easily differentiated from each other, i.e. nucleus, cytoplasm, red blood cells, etc. and based on the spectral residual error of fiber weighting factors are determined to enhance spectral features at certain wavelengths. Results of our experiment demonstrate the capability of multispectral imaging and its advantage compared to the conventional RGB imaging systems to delineate tissue structures with subtle colorimetric difference.

An overview of computational life science databases & exchange formats of relevance to chemical biology research.

PubMed

Smalter Hall, Aaron; Shan, Yunfeng; Lushington, Gerald; Visvanathan, Mahesh

2013-03-01

Databases and exchange formats describing biological entities such as chemicals and proteins, along with their relationships, are a critical component of research in life sciences disciplines, including chemical biology wherein small information about small molecule properties converges with cellular and molecular biology. Databases for storing biological entities are growing not only in size, but also in type, with many similarities between them and often subtle differences. The data formats available to describe and exchange these entities are numerous as well. In general, each format is optimized for a particular purpose or database, and hence some understanding of these formats is required when choosing one for research purposes. This paper reviews a selection of different databases and data formats with the goal of summarizing their purposes, features, and limitations. Databases are reviewed under the categories of 1) protein interactions, 2) metabolic pathways, 3) chemical interactions, and 4) drug discovery. Representation formats will be discussed according to those describing chemical structures, and those describing genomic/proteomic entities.

Positive exchange-bias and giant vertical hysteretic shift in La0.3Sr0.7FeO3/SrRuO3 bilayers

PubMed Central

Rana, Rakesh; Pandey, Parul; Singh, R. P.; Rana, D. S.

2014-01-01

The exchange-bias effects in the mosaic epitaxial bilayers of the itinerant ferromagnet (FM) SrRuO3 and the antiferromagnetic (AFM) charge-ordered La0.3Sr0.7FeO3 were investigated. An uncharacteristic low-field positive exchange bias, a cooling-field driven reversal of positive to negative exchange-bias and a layer thickness optimised unusual vertical magnetization shift were all novel facets of exchange bias realized for the first time in magnetic oxides. The successive magnetic training induces a transition from positive to negative exchange bias regime with changes in domain configurations. These observations are well corroborated by the hysteretic loop asymmetries which display the modifications in the AFM spin correlations. These exotic features emphasize the key role of i) mosaic disorder induced subtle interplay of competing AFM-superexchange and FM double exchange at the exchange biased interface and, ii) training induced irrecoverable alterations in the AFM spin structure. PMID:24569516

Novel method for edge detection of retinal vessels based on the model of the retinal vascular network and mathematical morphology

NASA Astrophysics Data System (ADS)

Xu, Lei; Zheng, Xiaoxiang; Zhang, Hengyi; Yu, Yajun

1998-09-01

Accurate edge detection of retinal vessels is a prerequisite for quantitative analysis of subtle morphological changes of retinal vessels under different pathological conditions. A novel method for edge detection of retinal vessels is presented in this paper. Methods: (1) Wavelet-based image preprocessing. (2) The signed edge detection algorithm and mathematical morphological operation are applied to get the approximate regions that contain retinal vessels. (3) By convolving the preprocessed image with a LoG operator only on the detected approximate regions of retinal vessels, followed by edges refining, clear edge maps of the retinal vessels are fast obtained. Results: A detailed performance evaluation together with the existing techniques is given to demonstrate the strong features of our method. Conclusions: True edge locations of retinal vessels can be fast detected with continuous structures of retinal vessels, less non- vessel segments left and insensitivity to noise. The method is also suitable for other application fields such as road edge detection.

Stratigraphic Correlation via Opportunity's Pancam of the Burns Formation, Meridiani Planum, Mars

NASA Astrophysics Data System (ADS)

Thompson, S. D.; Calvin, W. M.; Farrand, W. H.

2006-12-01

Spectral properties of Meridiani Planum hematite-rich Burns formation observed by Opportunity's Pancam have been described previously but not at minimum spatial scales. This study is of the fine scale visible and near- infrared spectral features within the sedimentary structures over the entire lateral extent explored by Opportunity across an 8 km traverse from Endurance to Victoria craters. Investigation of the bedrock has shown sub-centimeter thinly laminated evaporite deposits with few occurrences of festoon cross-bedding, massive bedding, and subtle differences in color and texture. Pancam data analyses of rock targets where sufficient spatial resolution (<10 mm) is achieved (within 10 m) constrain spectral parameters of laminar, erosional, and possible secondary diagenetic features. Results show differences of statistical significance in iron mineral varieties and phases in both vertical section and lateral extent of the Burns formation. Spectra exhibit a steep positive slope in the visible (432-753 nm) region and subtle changes in the near infrared (753-1009 nm) region ranging from flat, concave, to convex profiles. Maxima are typically in the 750-850 nm region but can occur as low as 673 nm and as high as 1009 nm with the latter usually from the lower albedo materials (i.e., spherules and basaltic sands). Positive slopes from 934-1009 nm in this region are consistent with the presence of hematite, commonly associated with the spherules. The higher albedo surfaces tend to have greatest negative slope in the longer wavelengths. This could result from intrinsic characteristics of the outcrop material or a significantly thick (i.e. >100 micron) dust deposit. Band depth images centered at 535 nm and 904 nm provide statistics on the relative occurrences of crystalline ferric oxide minerals. Rarely iron-rich signatures are present in individual laminations and not in the adjacent layers. Such occurrences could result from multiple iron-rich sedimentary events, secondary diagenetic products such as cementation or recrystallization, or an invasive fracture fill material. Comparisons of geomorphologic and spectroscopic mapping will be presented to show overall relationships of the Meridiani plains materials.

Microgravity

NASA Image and Video Library

1997-01-12

This is a large 2 mm crystal of histone octamer, grown on STS-81. A very dynamic structure which functions in many aspects of gene regulation from control of gene activity to the more subtle mechanisms of genetic imprinting. Principle Investigator is Dan Carter of New Century Pharmaceuticals.

Microstructure-property relationships in directionally solidified single crystal nickel-base superalloys

NASA Technical Reports Server (NTRS)

Mackay, R. A.; Nathal, M. V.

1986-01-01

Some of the microstructural features which influence the creep properties of directionally solidified and single crystal nickel-base superalloys are discussed. Gamma precipitate size and morphology, gamma-gamma lattice mismatch, phase instability, alloy composition, and processing variations are among the factors considered. Recent experimental results are reviewed and related to the operative deformation mechanisms and to the corresponding mechanical properties. Special emphasis is placed on the creep behavior of single crystal superalloys at high temperatures, where directional gamma coarsening is prominent, and at lower temperatures, where gamma coarsening rates are significantly reduced. It can be seen that very subtle changes in microstructural features can have profound effects on the subsequent properties of these materials.

Phase I Metabolic Stability and Electrophilic Reactivity of 2-Phenylaminophenylacetic Acid Derived Compounds.

PubMed

Pang, Yi Yun; Tan, Yee Min; Chan, Eric Chun Yong; Ho, Han Kiat

2016-07-18

Diclofenac and lumiracoxib are two highly analogous 2-phenylaminophenylacetic acid anti-inflammatory drugs exhibiting occasional dose-limiting hepatotoxicities. Prior data indicate that bioactivation and reactive metabolite formation play roles in the observed toxicity, but the exact chemical influence of the substituents remains elusive. In order to elucidate the role of chemical influence on metabolism related toxicity, metabolic stability and electrophilic reactivity were investigated for a series of structurally related analogues and their resulting metabolites. The resulting analogues embody progressive physiochemical changes through varying halogeno- and aliphatic substituents at two positions and were subjected to in vitro human liver microsomal metabolic stability and cell-based GSH depletion assays (to measure electrophilic reactivity). LC-MS/MS analysis of the GSH trapped reactive intermediates derived from the analogues was then used to identify the putative structures of reactive metabolites. We found that chemical modifications of the structural backbone led to noticeable perturbations of metabolic stability, electrophilic reactivity, and structures and composition of reactive metabolites. With the acquired data, the relationships between stability, reactivity, and toxicity were investigated in an attempt to correlate between Phase I metabolism and in vitro toxicity. A positive correlation was identified between reactivity and in vitro toxicity, indicating that electrophilic reactivity can be an indicator for in vitro toxicity. All in all, the effect of substituents on the structures and reactivity of the metabolites, however subtle the changes, should be taken into consideration during future drug design involving similar chemical features.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Voylov, D. N.; Griffin, P. J.; Mercado, B.

In this detailed analysis of the static structure factor S(Q) in several glass-forming liquids we show that the temperature variations of the width of the main diffraction peak Q(T ) correlate with the fragility of these liquids. Our observation suggests a direct connection between rather subtle structural changes and sharp slowing down of structural relaxation in glass-forming liquids. We also show that this observation can be rationalized using the Adam-Gibbs approach, through a connection between temperature variations of structural correlation length, lc 2 /Q, and the size of cooperatively rearranging regions.

Terra Cimmeria - False Color

NASA Image and Video Library

2016-10-11

The THEMIS VIS camera contains 5 filters. The data from different filters can be combined in multiple ways to create a false color image. These false color images may reveal subtle variations of the surface not easily identified in a single band image. Today's false color image shows dust devil tracks (dark blue linear feature) in Terra Cimmeria. Orbit Number: 43463 Latitude: -53.1551 Longitude: 125.069 Instrument: VIS Captured: 2011-10-01 23:55 http://photojournal.jpl.nasa.gov/catalog/PIA21009

Out-of-time-ordered measurements as a probe of quantum dynamics

NASA Astrophysics Data System (ADS)

Bordia, Pranjal; Alet, Fabien; Hosur, Pavan

2018-03-01

Probing the out-of-equilibrium dynamics of quantum matter has gained renewed interest owing to immense experimental progress in artificial quantum systems. Dynamical quantum measures such as the growth of entanglement entropy and out-of-time-ordered correlators (OTOCs) have been shown to provide great insight by exposing subtle quantum features invisible to traditional measures such as mass transport. However, measuring them in experiments requires either identical copies of the system, an ancilla qubit coupled to the whole system, or many measurements on a single copy, thereby making scalability extremely complex and hence, severely limiting their potential. Here, we introduce an alternative quantity, the out-of-time-ordered measurement (OTOM), which involves measuring a single observable on a single copy of the system, while retaining the distinctive features of the OTOCs. We show, theoretically, that OTOMs are closely related to OTOCs in a doubled system with the same quantum statistical properties as the original system. Using exact diagonalization, we numerically simulate classical mass transport, as well as quantum dynamics through computations of the OTOC, the OTOM, and the entanglement entropy in quantum spin chain models in various interesting regimes (including chaotic and many-body localized systems). Our results demonstrate that an OTOM can successfully reveal subtle aspects of quantum dynamics hidden to classical measures and, crucially, provide experimental access to them.

Developmental Thyroid Hormone Insufficiency Impairs Visual Contrast Sensitivity in Adult Male Offspring.

EPA Science Inventory

Severe thyroid hormone (TH) insufficiency during early development results in alterations in brain structure and function. Many environmental agents produce subtle alterations in TH status, but the dose-response relationships for such effects are unclear. We have previously demon...

Modulation of a Pore in the Capsid of JC Polyomavirus Reduces Infectivity and Prevents Exposure of the Minor Capsid Proteins

PubMed Central

Nelson, Christian D. S.; Ströh, Luisa J.; Gee, Gretchen V.; O'Hara, Bethany A.; Stehle, Thilo

2015-01-01

ABSTRACT JC polyomavirus (JCPyV) infection of immunocompromised individuals results in the fatal demyelinating disease progressive multifocal leukoencephalopathy (PML). The viral capsid of JCPyV is composed primarily of the major capsid protein virus protein 1 (VP1), and pentameric arrangement of VP1 monomers results in the formation of a pore at the 5-fold axis of symmetry. While the presence of this pore is conserved among polyomaviruses, its functional role in infection or assembly is unknown. Here, we investigate the role of the 5-fold pore in assembly and infection of JCPyV by generating a panel of mutant viruses containing amino acid substitutions of the residues lining this pore. Multicycle growth assays demonstrated that the fitness of all mutants was reduced compared to that of the wild-type virus. Bacterial expression of VP1 pentamers containing substitutions to residues lining the 5-fold pore did not affect pentamer assembly or prevent association with the VP2 minor capsid protein. The X-ray crystal structures of selected pore mutants contained subtle changes to the 5-fold pore, and no other changes to VP1 were observed. Pore mutant pseudoviruses were not deficient in assembly, packaging of the minor capsid proteins, or binding to cells or in transport to the host cell endoplasmic reticulum. Instead, these mutant viruses were unable to expose VP2 upon arrival to the endoplasmic reticulum, a step that is critical for infection. This study demonstrated that the 5-fold pore is an important structural feature of JCPyV and that minor modifications to this structure have significant impacts on infectious entry. IMPORTANCE JCPyV is an important human pathogen that causes a severe neurological disease in immunocompromised individuals. While the high-resolution X-ray structure of the major capsid protein of JCPyV has been solved, the importance of a major structural feature of the capsid, the 5-fold pore, remains poorly understood. This pore is conserved across polyomaviruses and suggests either that these viruses have limited structural plasticity in this region or that this pore is important in infection or assembly. Using a structure-guided mutational approach, we showed that modulation of this pore severely inhibits JCPyV infection. These mutants do not appear deficient in assembly or early steps in infectious entry and are instead reduced in their ability to expose a minor capsid protein in the host cell endoplasmic reticulum. Our work demonstrates that the 5-fold pore is an important structural feature for JCPyV. PMID:25609820

Plant phenolics and absorption features in vegetation reflectance spectra near 1.66 μm

USGS Publications Warehouse

Kokaly, Raymond F.; Skidmore, Andrew K

2015-01-01

Past laboratory and field studies have quantified phenolic substances in vegetative matter from reflectance measurements for understanding plant response to herbivores and insect predation. Past remote sensing studies on phenolics have evaluated crop quality and vegetation patterns caused by bedrock geology and associated variations in soil geochemistry. We examined spectra of pure phenolic compounds, common plant biochemical constituents, dry leaves, fresh leaves, and plant canopies for direct evidence of absorption features attributable to plant phenolics. Using spectral feature analysis with continuum removal, we observed that a narrow feature at 1.66 μm is persistent in spectra of manzanita, sumac, red maple, sugar maple, tea, and other species. This feature was consistent with absorption caused by aromatic C-H bonds in the chemical structure of phenolic compounds and non-hydroxylated aromatics. Because of overlapping absorption by water, the feature was weaker in fresh leaf and canopy spectra compared to dry leaf measurements. Simple linear regressions of feature depth and feature area with polyphenol concentration in tea resulted in high correlations and low errors (% phenol by dry weight) at the dry leaf (r2 = 0.95, RMSE = 1.0%, n = 56), fresh leaf (r2 = 0.79, RMSE = 2.1%, n = 56), and canopy (r2 = 0.78, RMSE = 1.0%, n = 13) levels of measurement. Spectra of leaves, needles, and canopies of big sagebrush and evergreens exhibited a weak absorption feature centered near 1.63 μm, short ward of the phenolic compounds, possibly consistent with terpenes. This study demonstrates that subtle variation in vegetation spectra in the shortwave infrared can directly indicate biochemical constituents and be used to quantify them. Phenolics are of lesser abundance compared to the major plant constituents but, nonetheless, have important plant functions and ecological significance. Additional research is needed to advance our understanding of the spectral influences of plant phenolics and terpenes relative to dominant leaf biochemistry (water, chlorophyll, protein/nitrogen, cellulose, and lignin).

Tertiary and Quaternary tectonic faulting in southernmost Illinois

USGS Publications Warehouse

Nelson, W.J.; Denny, F.B.; Devera, J.A.; Follmer, L.R.; Masters, J.M.

1997-01-01

Tertiary and/or Quaternary tectonic faulting is documented in three areas of southernmost Illinois: the Fluorspar Area Fault Complex (FAFC) in Pope and Massac Counties, the Ste. Genevieve Fault Zone (SGFZ) in Alexander and Union Counties, and the Commerce Fault Zone (CFZ) in Alexander County. In the FAFC, faults that strike NE and NNE displace Mounds Gravel (late Miocene to early Pleistocene) and, locally, the Metropolis terrace gravel (Pleistocene; pre-Woodfordian). No Woodfordian or younger deposits are deformed. Faults typically outline narrow, linear grabens that formed under tension with a component of strike slip. North-south to NW-trending vertical faults near the southeast end of the SGFZ displace Eocene sediments. Again, faults outline narrow grabens and show indications of strike slip. Deformed Quaternary sediments have not been observed. The CFZ, which trends northeast, displaces Mounds Gravel in Illinois and units as young as Peoria Silt (Woodfordian) in Missouri. Quaternary movement has been interpreted as right-lateral strike-slip. The CFZ coincides with a subtle gravity and magnetic lineament and seems to reflect a major feature in the basement. Surface expression in Illinois is subtle, but mafic and ultramafic intrusions, hydrothermal alteration and small faults align with the Commerce geophysical lineament. Earthquake foci in Missouri and Illinois lie on or close to the CFZ; some focal mechanisms fit the fault trend. Among these structures, only the CFZ exhibits slip that conforms to the current stress field (principal compressive stress axis E-W to ENE-WSW). Possibly, the stress field changed during Neogene time. Alternatively, high fluid pressures or local stress concentrations may have induced slip on less favorably oriented fractures. Tighter constraints are needed on timing, magnitude, and direction of Neogene displacement. ?? 1997 Elsevier Science B.V.

Applications of Fault Detection in Vibrating Structures

NASA Technical Reports Server (NTRS)

Eure, Kenneth W.; Hogge, Edward; Quach, Cuong C.; Vazquez, Sixto L.; Russell, Andrew; Hill, Boyd L.

2012-01-01

Structural fault detection and identification remains an area of active research. Solutions to fault detection and identification may be based on subtle changes in the time series history of vibration signals originating from various sensor locations throughout the structure. The purpose of this paper is to document the application of vibration based fault detection methods applied to several structures. Overall, this paper demonstrates the utility of vibration based methods for fault detection in a controlled laboratory setting and limitations of applying the same methods to a similar structure during flight on an experimental subscale aircraft.

Morphological similarity and ecological overlap in two rotifer species.

PubMed

Gabaldón, Carmen; Montero-Pau, Javier; Serra, Manuel; Carmona, María José

2013-01-01

Co-occurrence of cryptic species raises theoretically relevant questions regarding their coexistence and ecological similarity. Given their great morphological similitude and close phylogenetic relationship (i.e., niche retention), these species will have similar ecological requirements and are expected to have strong competitive interactions. This raises the problem of finding the mechanisms that may explain the coexistence of cryptic species and challenges the conventional view of coexistence based on niche differentiation. The cryptic species complex of the rotifer Brachionus plicatilis is an excellent model to study these questions and to test hypotheses regarding ecological differentiation. Rotifer species within this complex are filtering zooplankters commonly found inhabiting the same ponds across the Iberian Peninsula and exhibit an extremely similar morphology-some of them being even virtually identical. Here, we explore whether subtle differences in body size and morphology translate into ecological differentiation by comparing two extremely morphologically similar species belonging to this complex: B. plicatilis and B. manjavacas. We focus on three key ecological features related to body size: (1) functional response, expressed by clearance rates; (2) tolerance to starvation, measured by growth and reproduction; and (3) vulnerability to copepod predation, measured by the number of preyed upon neonates. No major differences between B. plicatilis and B. manjavacas were found in the response to these features. Our results demonstrate the existence of a substantial niche overlap, suggesting that the subtle size differences between these two cryptic species are not sufficient to explain their coexistence. This lack of evidence for ecological differentiation in the studied biotic niche features is in agreement with the phylogenetic limiting similarity hypothesis but requires a mechanistic explanation of the coexistence of these species not based on differentiation related to biotic niche axes.

Systemic lupus erythematosus-associated neutrophilic dermatosis--an underrecognized neutrophilic dermatosis in patients with systemic lupus erythematosus.

PubMed

Larson, Allison R; Granter, Scott R

2014-03-01

Neutrophilic dermatoses are an uncommon manifestation of lupus. We describe the clinical and histopathologic features of 14 patients with systemic lupus erythematosus (SLE) and neutrophilic dermatoses, 2 of whom had no prior history of SLE. Thirteen patients were female, ranging in age from 27 to 62 years (mean age, 42.8 years). One patient was a 20-year-old man. Most lesions were described as erythematous papules and plaques and showed annular morphology in 6 patients and a photodistribution in 2 patients. Histopathologic examination in all cases showed an interstitial neutrophilic infiltrate with leukocytoclasis that ranged from sparse in 5 cases and moderate to dense in 9 cases. With one exception, those cases with moderate to dense infiltrates resembled Sweet's syndrome at scanning magnification. Two cases resembled bullous SLE, and 1 case showed overlapping features of bullous SLE and Sweet's syndrome. Interface changes were seen in 8 patients, which were subtle and vacuolar in 7. One case was associated with a florid interface tissue reaction. Dermal mucin was seen in 4 cases and was a prominent feature in only one of these. One case showed a minute discrete focus resembling palisaded neutrophilic and granulomatous dermatitis. It is important to consider SLE-associated neutrophilic dermatosis in the differential diagnosis of neutrophilic tissue reactions particularly because some patients will have no prior history of lupus. It is also important to be aware of the broad histologic spectrum that may be encountered in SLE-associated neutrophilic dermatosis, ranging from subtle paucicellular lesions to florid Sweet's-like lesions associated with a dense neutrophilic infiltrate. Copyright © 2014 Elsevier Inc. All rights reserved.

Morphological Similarity and Ecological Overlap in Two Rotifer Species

PubMed Central

Gabaldón, Carmen; Montero-Pau, Javier; Serra, Manuel; Carmona, María José

2013-01-01

Co-occurrence of cryptic species raises theoretically relevant questions regarding their coexistence and ecological similarity. Given their great morphological similitude and close phylogenetic relationship (i.e., niche retention), these species will have similar ecological requirements and are expected to have strong competitive interactions. This raises the problem of finding the mechanisms that may explain the coexistence of cryptic species and challenges the conventional view of coexistence based on niche differentiation. The cryptic species complex of the rotifer Brachionus plicatilis is an excellent model to study these questions and to test hypotheses regarding ecological differentiation. Rotifer species within this complex are filtering zooplankters commonly found inhabiting the same ponds across the Iberian Peninsula and exhibit an extremely similar morphology—some of them being even virtually identical. Here, we explore whether subtle differences in body size and morphology translate into ecological differentiation by comparing two extremely morphologically similar species belonging to this complex: B. plicatilis and B. manjavacas. We focus on three key ecological features related to body size: (1) functional response, expressed by clearance rates; (2) tolerance to starvation, measured by growth and reproduction; and (3) vulnerability to copepod predation, measured by the number of preyed upon neonates. No major differences between B. plicatilis and B. manjavacas were found in the response to these features. Our results demonstrate the existence of a substantial niche overlap, suggesting that the subtle size differences between these two cryptic species are not sufficient to explain their coexistence. This lack of evidence for ecological differentiation in the studied biotic niche features is in agreement with the phylogenetic limiting similarity hypothesis but requires a mechanistic explanation of the coexistence of these species not based on differentiation related to biotic niche axes. PMID:23451154

The temporolimbic system theory of positive schizophrenic symptoms.

PubMed

Bogerts, B

1997-01-01

This article proposes that subtle structural and functional disturbance of limbic key structures in the medial temporal lobe-especially of the left hippocampal formation and parahippocampal gyrus-can explain the so-called positive symptoms of schizophrenia. After presenting pathophysiological considerations linking limbic dysfunction to schizophrenia, the article reviews evidence from structural, biochemical, and functional studies supporting the theory. Also discussed here are neurodevelopmental and laterality aspects, as well as predictions, questions, and future tasks derived from the theory.

Odd–even structural sensitivity on dynamics in network-forming ionic liquids

DOE PAGES

Yang, Ke; Cai, Zhikun; Tyagi, Madhusudan; ...

2016-04-13

Understanding structural sensitivity on properties of materials is an important step toward the rational design of materials. As a compelling case of sensitive structure-property relationship, an odd-even effect refers to the alternating trend of physical or chemical properties on odd/even number of repeating structural units. In crystalline or semi-crystalline materials, such odd-even variations of macroscopic properties emerge as manifestations of differences in the periodic packing patterns of molecules. Therefore, due to the lack of long-range order, such odd-even phenomenon is not expected in liquids. Herein, we report the discovery of a remarkable odd-even effect of the dynamical properties in themore » liquid phase, which challenges the traditional periodic packing explanations. In a class of network-forming ionic liquid (NIL), using incoherent quasi-elastic neutron scattering measurements, we measured the dynamical properties including the diffusion coefficient and the rotational relaxation time. These dynamical properties showed pronounced alternating trends with increased number of methylene (–CH 2– ) groups in the backbone. Meanwhile, the structure factor S(Q) showed no long-range periodic packing of molecules, while the pair distribution function g(r) revealed subtle differences in the local molecular morphology. As a result, the observed dynamical odd-even phenomenon in liquids showed that profound dynamical changes originate from subtle local structural differences.« less

Superpixel-Augmented Endmember Detection for Hyperspectral Images

NASA Technical Reports Server (NTRS)

Thompson, David R.; Castano, Rebecca; Gilmore, Martha

2011-01-01

Superpixels are homogeneous image regions comprised of several contiguous pixels. They are produced by shattering the image into contiguous, homogeneous regions that each cover between 20 and 100 image pixels. The segmentation aims for a many-to-one mapping from superpixels to image features; each image feature could contain several superpixels, but each superpixel occupies no more than one image feature. This conservative segmentation is relatively easy to automate in a robust fashion. Superpixel processing is related to the more general idea of improving hyperspectral analysis through spatial constraints, which can recognize subtle features at or below the level of noise by exploiting the fact that their spectral signatures are found in neighboring pixels. Recent work has explored spatial constraints for endmember extraction, showing significant advantages over techniques that ignore pixels relative positions. Methods such as AMEE (automated morphological endmember extraction) express spatial influence using fixed isometric relationships a local square window or Euclidean distance in pixel coordinates. In other words, two pixels covariances are based on their spatial proximity, but are independent of their absolute location in the scene. These isometric spatial constraints are most appropriate when spectral variation is smooth and constant over the image. Superpixels are simple to implement, efficient to compute, and are empirically effective. They can be used as a preprocessing step with any desired endmember extraction technique. Superpixels also have a solid theoretical basis in the hyperspectral linear mixing model, making them a principled approach for improving endmember extraction. Unlike existing approaches, superpixels can accommodate non-isometric covariance between image pixels (characteristic of discrete image features separated by step discontinuities). These kinds of image features are common in natural scenes. Analysts can substitute superpixels for image pixels during endmember analysis that leverages the spatial contiguity of scene features to enhance subtle spectral features. Superpixels define populations of image pixels that are independent samples from each image feature, permitting robust estimation of spectral properties, and reducing measurement noise in proportion to the area of the superpixel. This permits improved endmember extraction, and enables automated search for novel and constituent minerals in very noisy, hyperspatial images. This innovation begins with a graph-based segmentation based on the work of Felzenszwalb et al., but then expands their approach to the hyperspectral image domain with a Euclidean distance metric. Then, the mean spectrum of each segment is computed, and the resulting data cloud is used as input into sequential maximum angle convex cone (SMACC) endmember extraction.

The dynamics of interacting salt structures and associated fluid flow in the western Norwegian-Danish Basin

NASA Astrophysics Data System (ADS)

Olsen, Mikkel S.; Clausen, Ole R.; Andresen, Katrine J.; Korstgård, John A.

2015-04-01

Minor secondary structures observed along the flanks of major salt structures in the Norwegian-Danish Basin appear to be generated mainly during the early stages of halokinesis. Seismic anomalies in the cover sediments at the flanks of the major salt structures and in relation to one of the secondary structures show several circular patterns. The circular patterns are generally interpreted as faults related to collapsing salt, indicating a subtle and dynamic cannibalization relationship between the secondary structure and the main diapir. High-amplitude reflections interpreted as either entrapped gas along the circular faults or diagenetic changes induced by the fluids originating from the salt-sediment interface generally enhances the seismic appearance of the circular faults, but potentially also disturb the seismic imaging of the faults. Other secondary salt structures, with a similar geometry, do not show sign of collapse, apparently due to a greater distance from the main salt structures and therefore not within the reach of being cannibalized by these. The observations furthermore suggest a trend showing a more advanced development of the main salt structures when the secondary structures are cannibalized. The lateral distribution of the main salt structures thus appears to be controlled not only by the initial thickness of the Zechstein salt, and possible underlying structures, but also by subtle variations in the location and evolution of secondary structures. The secondary structures have a major impact on the drainage of the deep Mesozoic succession as indicated by the fluid flow pattern also observed in the study, which emphasizes that a detailed mapping of salt structures including secondary structures at the flanks is of major importance during evaluation of petroleum systems in areas dominated by halokinesis.

Leigh syndrome: MRI findings in two children.

PubMed

Kartikasalwah, Al; Lh, Ngu

2010-01-01

Leigh syndrome is a progressive neurodegenerative disorder of childhood. The symmetrical necrotic lesions in the basal ganglia and/or brainstem which appear as hyperintense lesions on T2-weighted MRI is characteristic and one of the essential diagnostic criteria. Recognising this MR imaging pattern in a child with neurological problems should prompt the clinician to investigate for Leigh syndrome. We present here two cases of Leigh syndrome due to different biochemical/genetic defects, and discuss the subtle differences in their MR neuroimaging features.

ION Configuration Editor

NASA Technical Reports Server (NTRS)

Borgen, Richard L.

2013-01-01

The configuration of ION (Inter - planetary Overlay Network) network nodes is a manual task that is complex, time-consuming, and error-prone. This program seeks to accelerate this job and produce reliable configurations. The ION Configuration Editor is a model-based smart editor based on Eclipse Modeling Framework technology. An ION network designer uses this Eclipse-based GUI to construct a data model of the complete target network and then generate configurations. The data model is captured in an XML file. Intrinsic editor features aid in achieving model correctness, such as field fill-in, type-checking, lists of valid values, and suitable default values. Additionally, an explicit "validation" feature executes custom rules to catch more subtle model errors. A "survey" feature provides a set of reports providing an overview of the entire network, enabling a quick assessment of the model s completeness and correctness. The "configuration" feature produces the main final result, a complete set of ION configuration files (eight distinct file types) for each ION node in the network.

Understanding Deep Representations Learned in Modeling Users Likes.

PubMed

Guntuku, Sharath Chandra; Zhou, Joey Tianyi; Roy, Sujoy; Lin, Weisi; Tsang, Ivor W

2016-08-01

Automatically understanding and discriminating different users' liking for an image is a challenging problem. This is because the relationship between image features (even semantic ones extracted by existing tools, viz., faces, objects, and so on) and users' likes is non-linear, influenced by several subtle factors. This paper presents a deep bi-modal knowledge representation of images based on their visual content and associated tags (text). A mapping step between the different levels of visual and textual representations allows for the transfer of semantic knowledge between the two modalities. Feature selection is applied before learning deep representation to identify the important features for a user to like an image. The proposed representation is shown to be effective in discriminating users based on images they like and also in recommending images that a given user likes, outperforming the state-of-the-art feature representations by  ∼ 15 %-20%. Beyond this test-set performance, an attempt is made to qualitatively understand the representations learned by the deep architecture used to model user likes.

Electron Transfer Governed Crystal Transformation of Tungsten Trioxide upon Li Ions Intercalation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Zhiguo; He, Yang; Gu, Meng

2016-09-21

Reversible insertion/extraction of ions into a host lattice constitutes the fundamental operating principle of rechargeable battery and electrochromic materials. It is far more commonly observed that insertion of ions into a host lattice can lead to structural evolution of the host lattice, and for the most cases such a lattice evolution is subtle. However, it has never been clear as what kind of factors to control such a lattice structural evolution. Based on tungsten trioxide (WO3) model crystal, we use in situ transmission electron microscopy (TEM) and first principles calculation to explore the nature of Li ions intercalation induced crystalmore » symmetry evolution of WO3. We discovered that Li insertion into the octahedral cavity of WO3 lattice will lead to a low to high symmetry transition, featuring a sequential monoclinic→tetragonal→cubic phase transition. The first principle calculation reveals that the phase transition is essentially governed by the electron transfer from Li to the WO6 octahedrons, which effectively leads to the weakening the W-O bond and modifying system band structure, resulting in an insulator to metal transition. The observation of the electronic effect on crystal symmetry and conductivity is significant, providing deep insights on the intercalation reactions in secondary rechargeable ion batteries and the approach for tailoring the functionalities of material based on insertion of ions in the lattice.« less

On the Sequence-Directed Nature of Human Gene Mutation: The Role of Genomic Architecture and the Local DNA Sequence Environment in Mediating Gene Mutations Underlying Human Inherited Disease

PubMed Central

Cooper, David N.; Bacolla, Albino; Férec, Claude; Vasquez, Karen M.; Kehrer-Sawatzki, Hildegard; Chen, Jian-Min

2011-01-01

Different types of human gene mutation may vary in size, from structural variants (SVs) to single base-pair substitutions, but what they all have in common is that their nature, size and location are often determined either by specific characteristics of the local DNA sequence environment or by higher-order features of the genomic architecture. The human genome is now recognized to contain ‘pervasive architectural flaws’ in that certain DNA sequences are inherently mutation-prone by virtue of their base composition, sequence repetitivity and/or epigenetic modification. Here we explore how the nature, location and frequency of different types of mutation causing inherited disease are shaped in large part, and often in remarkably predictable ways, by the local DNA sequence environment. The mutability of a given gene or genomic region may also be influenced indirectly by a variety of non-canonical (non-B) secondary structures whose formation is facilitated by the underlying DNA sequence. Since these non-B DNA structures can interfere with subsequent DNA replication and repair, and may serve to increase mutation frequencies in generalized fashion (i.e. both in the context of subtle mutations and SVs), they have the potential to serve as a unifying concept in studies of mutational mechanisms underlying human inherited disease. PMID:21853507

Structural Evolution of Differential Amino Acid Effector Regulation in Plant Chorismate Mutases*

PubMed Central

Westfall, Corey S.; Xu, Ang; Jez, Joseph M.

2014-01-01

Chorismate mutase converts chorismate into prephenate for aromatic amino acid biosynthesis. To understand the molecular basis of allosteric regulation in the plant chorismate mutases, we analyzed the three Arabidopsis thaliana chorismate mutase isoforms (AtCM1–3) and determined the x-ray crystal structures of AtCM1 in complex with phenylalanine and tyrosine. Functional analyses show a wider range of effector control in the Arabidopsis chorismate mutases than previously reported. AtCM1 is activated by tryptophan with phenylalanine and tyrosine acting as negative effectors; however, tryptophan, cysteine, and histidine activate AtCM3. AtCM2 is a nonallosteric form. The crystal structure of AtCM1 in complex with tyrosine and phenylalanine identifies differences in the effector sites of the allosterically regulated yeast enzyme and the other two Arabidopsis isoforms. Site-directed mutagenesis of residues in the effector site reveals key features leading to differential effector regulation in these enzymes. In AtCM1, mutations of Gly-213 abolish allosteric regulation, as observed in AtCM2. A second effector site position, Gly-149 in AtCM1 and Asp-132 in AtCM3, controls amino acid effector specificity in AtCM1 and AtCM3. Comparisons of chorismate mutases from multiple plants suggest that subtle differences in the effector site are conserved in different lineages and may lead to specialized regulation of this branch point enzyme. PMID:25160622

Passive Infrared Thermographic Imaging for Mobile Robot Object Identification

NASA Astrophysics Data System (ADS)

Hinders, M. K.; Fehlman, W. L.

2010-02-01

The usefulness of thermal infrared imaging as a mobile robot sensing modality is explored, and a set of thermal-physical features used to characterize passive thermal objects in outdoor environments is described. Objects that extend laterally beyond the thermal camera's field of view, such as brick walls, hedges, picket fences, and wood walls as well as compact objects that are laterally within the thermal camera's field of view, such as metal poles and tree trunks, are considered. Classification of passive thermal objects is a subtle process since they are not a source for their own emission of thermal energy. A detailed analysis is included of the acquisition and preprocessing of thermal images, as well as the generation and selection of thermal-physical features from these objects within thermal images. Classification performance using these features is discussed, as a precursor to the design of a physics-based model to automatically classify these objects.

ARC-1990-AC91-2004

NASA Image and Video Library

1990-02-14

Range : 1.7 million miles This colorized picture of Venus was taken about 6 days after Galileo's closest approach to the planet. It has been colorized to a bluish hue to emphasize subtle contrasts in the cloud markings and to indicate that it was taken through a violet filter. Features in the sulfuric acid clouds near the top of the planet's atmosphere are most prominent in violet and ultraviolet light. This image shows the east-to-west-trending cloud banding and the brighter polar hoods familiar from past studies of Venus. The features are embedded in winds that flow from east to west at about 230 mph. The smallest features visible are about 45 miles across. An intriguing filamentary dark pattern is seen immediately left of the bright region at the subsolar point (equatorial 'noon'). North is at the top and the evening terminator is to the left.

Fault zone structure and inferences on past activities of the active Shanchiao Fault in the Taipei metropolis, northern Taiwan

NASA Astrophysics Data System (ADS)

Chen, C.; Lee, J.; Chan, Y.; Lu, C.

2010-12-01

The Taipei Metropolis, home to around 10 million people, is subject to seismic hazard originated from not only distant faults or sources scattered throughout the Taiwan region, but also active fault lain directly underneath. Northern Taiwan including the Taipei region is currently affected by post-orogenic (Penglai arc-continent collision) processes related to backarc extension of the Ryukyu subduction system. The Shanchiao Fault, an active normal fault outcropping along the western boundary of the Taipei Basin and dipping to the east, is investigated here for its subsurface structure and activities. Boreholes records in the central portion of the fault were analyzed to document the stacking of post- Last Glacial Maximum growth sediments, and a tulip flower structure is illuminated with averaged vertical slip rate of about 3 mm/yr. Similar fault zone architecture and post-LGM tectonic subsidence rate is also found in the northern portion of the fault. A correlation between geomorphology and structural geology in the Shanchiao Fault zone demonstrates an array of subtle geomorphic scarps corresponds to the branch fault while the surface trace of the main fault seems to be completely erased by erosion and sedimentation. Such constraints and knowledge are crucial in earthquake hazard evaluation and mitigation in the Taipei Metropolis, and in understanding the kinematics of transtensional tectonics in northern Taiwan. Schematic 3D diagram of the fault zone in the central portion of the Shanchiao Fault, displaying regional subsurface geology and its relation to topographic features.

Electronic structure of ruthenium-doped iron chalcogenides

NASA Astrophysics Data System (ADS)

Winiarski, M. J.; Samsel-Czekała, M.; Ciechan, A.

2014-12-01

The structural and electronic properties of hypothetical RuxFe1-xSe and RuxFe1-xTe systems have been investigated from first principles within the density functional theory (DFT). Reasonable values of lattice parameters and chalcogen atomic positions in the tetragonal unit cell of iron chalcogenides have been obtained with the use of norm-conserving pseudopotentials. The well known discrepancies between experimental data and DFT-calculated results for structural parameters of iron chalcogenides are related to the semicore atomic states which were frozen in the used here approach. Such an approach yields valid results of the electronic structures of the investigated compounds. The Ru-based chalcogenides exhibit the same topology of the Fermi surface (FS) as that of FeSe, differing only in subtle FS nesting features. Our calculations predict that the ground states of RuSe and RuTe are nonmagnetic, whereas those of the solid solutions RuxFe1-xSe and RuxFe1-xTe become the single- and double-stripe antiferromagnetic, respectively. However, the calculated stabilization energy values are comparable for each system. The phase transitions between these magnetic arrangements may be induced by slight changes of the chalcogen atom positions and the lattice parameters a in the unit cell of iron selenides and tellurides. Since the superconductivity in iron chalcogenides is believed to be mediated by the spin fluctuations in single-stripe magnetic phase, the RuxFe1-xSe and RuxFe1-xTe systems are good candidates for new superconducting iron-based materials.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoak, T.E.; Decker, A.D.

Mesaverde Group reservoirs in the Piceance Basin, Western Colorado contain a large reservoir base. Attempts to exploit this resource base are stymied by low permeability reservoir conditions. The presence of abundant natural fracture systems throughout this basin, however, does permit economic production. Substantial production is associated with fractured reservoirs in Divide Creek, Piceance Creek, Wolf Creek, White River Dome, Plateau, Shire Gulch, Grand Valley, Parachute and Rulison fields. Successful Piceance Basin gas production requires detailed information about fracture networks and subsurface gas and water distribution in an overall gas-centered basin geometry. Assessment of these three parameters requires an integrated basinmore » analysis incorporating conventional subsurface geology, seismic data, remote sensing imagery analysis, and an analysis of regional tectonics. To delineate the gas-centered basin geometry in the Piceance Basin, a regional cross-section spanning the basin was constructed using hydrocarbon and gamma radiation logs. The resultant hybrid logs were used for stratigraphic correlations in addition to outlining the trans-basin gas-saturated conditions. The magnitude of both pressure gradients (paludal and marine intervals) is greater than can be generated by a hydrodynamic model. To investigate the relationships between structure and production, detailed mapping of the basin (top of the Iles Formation) was used to define subtle subsurface structures that control fractured reservoir development. The most productive fields in the basin possess fractured reservoirs. Detailed studies in the Grand Valley-Parachute-Rulison and Shire Gulch-Plateau fields indicate that zones of maximum structural flexure on kilometer-scale structural features are directly related to areas of enhanced production.« less

State Action and Labor Structure Change in Mexico.

ERIC Educational Resources Information Center

Fuller, Bruce; And Others

1990-01-01

Examines how the Mexican government's penetration into 299 rural and urban counties, 1900-40, was related to growth in trade and service jobs. Emphasizes the government's support for written literacy and mass schooling as subtle strategies for incorporating peasants into urban institutions. Contains 39 references. (SV)

Microgravity

NASA Image and Video Library

2000-05-05

This computer graphic depicts the relative complexity of crystallizing large proteins in order to study their structures through x-ray crystallography. Insulin is a vital protein whose structure has several subtle points that scientists are still trying to determine. Large molecules such as insuline are complex with structures that are comparatively difficult to understand. For comparison, a sugar molecule (which many people have grown as hard crystals in science glass) and a water molecule are shown. These images were produced with the Macmolecule program. Photo credit: NASA/Marshall Space Flight Center (MSFC)

Preliminary results from an investigation of AIS-1 data over an area of epithermal alteration: Plateau, Northern Queensland, Australia

NASA Technical Reports Server (NTRS)

Mackin, Steve; Munday, Tim; Hook, Simon

1987-01-01

Airborne Imaging Spectrometer-1 (AIS-1) data were flown over undifferentiated sequences of acid to intermediate volcanics and intrusives; meta-sediments; and a series of partially lateritized sedimentary rocks. The area exhibits a considerable spectral variability, after the suppression of striping effects. Log residual, and Internal Average Relative Reflectance (IARR) analytical techniques were used to enhance mineralogically related spectral features. Both methods produce similar results, but did not visually highlight mineral absorption features due to processing artifacts in areas of significant vegetation cover. The enhancement of mineral related absorption features was achieved using a hybrid processing approach based on the relative reflectance differences between vegetated and non-vegetated surfaces at 1.2 and 2.1 micron. The result is an image with little overall contrast, but which enhances the more subtle spectral features believed to be associated with clays and epidote. The AIS data was subject to interactive analysis using SPAM. Clear separation of clay and epidote related absorption features was apparent, and the identification of kaolinite was possible despite detrimental spectral effects.

Interactions of Multimodal Ligands with Proteins: Insights into Selectivity Using Molecular Dynamics Simulations.

PubMed

Parimal, Siddharth; Garde, Shekhar; Cramer, Steven M

2015-07-14

Fundamental understanding of protein-ligand interactions is important to the development of efficient bioseparations in multimodal chromatography. Here we employ molecular dynamics (MD) simulations to investigate the interactions of three different proteins--ubiquitin, cytochrome C, and α-chymotrypsinogen A, sampling a range of charge from +1e to +9e--with two multimodal chromatographic ligands containing similar chemical moieties--aromatic, carboxyl, and amide--in different structural arrangements. We use a spherical harmonic expansion to analyze ligand and individual moiety density profiles around the proteins. We find that the Capto MMC ligand, which contains an additional aliphatic group, displays stronger interactions than Nuvia CPrime ligand with all three proteins. Studying the ligand densities at the moiety level suggests that hydrophobic interactions play a major role in determining the locations of high ligand densities. Finally, the greater structural flexibility of the Capto MMC ligand compared to that of the Nuvia cPrime ligand allows for stronger structural complementarity and enables stronger hydrophobic interactions. These subtle and not-so-subtle differences in binding affinities and modalities for multimodal ligands can result in significantly different binding behavior towards proteins with important implications for bioprocessing.

Decoding subtle forearm flexions using fractal features of surface electromyogram from single and multiple sensors.

PubMed

Arjunan, Sridhar Poosapadi; Kumar, Dinesh Kant

2010-10-21

Identifying finger and wrist flexion based actions using a single channel surface electromyogram (sEMG) can lead to a number of applications such as sEMG based controllers for near elbow amputees, human computer interface (HCI) devices for elderly and for defence personnel. These are currently infeasible because classification of sEMG is unreliable when the level of muscle contraction is low and there are multiple active muscles. The presence of noise and cross-talk from closely located and simultaneously active muscles is exaggerated when muscles are weakly active such as during sustained wrist and finger flexion. This paper reports the use of fractal properties of sEMG to reliably identify individual wrist and finger flexion, overcoming the earlier shortcomings. SEMG signal was recorded when the participant maintained pre-specified wrist and finger flexion movements for a period of time. Various established sEMG signal parameters such as root mean square (RMS), Mean absolute value (MAV), Variance (VAR) and Waveform length (WL) and the proposed fractal features: fractal dimension (FD) and maximum fractal length (MFL) were computed. Multi-variant analysis of variance (MANOVA) was conducted to determine the p value, indicative of the significance of the relationships between each of these parameters with the wrist and finger flexions. Classification accuracy was also computed using the trained artificial neural network (ANN) classifier to decode the desired subtle movements. The results indicate that the p value for the proposed feature set consisting of FD and MFL of single channel sEMG was 0.0001 while that of various combinations of the five established features ranged between 0.009 - 0.0172. From the accuracy of classification by the ANN, the average accuracy in identifying the wrist and finger flexions using the proposed feature set of single channel sEMG was 90%, while the average accuracy when using a combination of other features ranged between 58% and 73%. The results show that the MFL and FD of a single channel sEMG recorded from the forearm can be used to accurately identify a set of finger and wrist flexions even when the muscle activity is very weak. A comparison with other features demonstrates that this feature set offers a dramatic improvement in the accuracy of identification of the wrist and finger movements. It is proposed that such a system could be used to control a prosthetic hand or for a human computer interface.

Decoding subtle forearm flexions using fractal features of surface electromyogram from single and multiple sensors

PubMed Central

2010-01-01

Background Identifying finger and wrist flexion based actions using a single channel surface electromyogram (sEMG) can lead to a number of applications such as sEMG based controllers for near elbow amputees, human computer interface (HCI) devices for elderly and for defence personnel. These are currently infeasible because classification of sEMG is unreliable when the level of muscle contraction is low and there are multiple active muscles. The presence of noise and cross-talk from closely located and simultaneously active muscles is exaggerated when muscles are weakly active such as during sustained wrist and finger flexion. This paper reports the use of fractal properties of sEMG to reliably identify individual wrist and finger flexion, overcoming the earlier shortcomings. Methods SEMG signal was recorded when the participant maintained pre-specified wrist and finger flexion movements for a period of time. Various established sEMG signal parameters such as root mean square (RMS), Mean absolute value (MAV), Variance (VAR) and Waveform length (WL) and the proposed fractal features: fractal dimension (FD) and maximum fractal length (MFL) were computed. Multi-variant analysis of variance (MANOVA) was conducted to determine the p value, indicative of the significance of the relationships between each of these parameters with the wrist and finger flexions. Classification accuracy was also computed using the trained artificial neural network (ANN) classifier to decode the desired subtle movements. Results The results indicate that the p value for the proposed feature set consisting of FD and MFL of single channel sEMG was 0.0001 while that of various combinations of the five established features ranged between 0.009 - 0.0172. From the accuracy of classification by the ANN, the average accuracy in identifying the wrist and finger flexions using the proposed feature set of single channel sEMG was 90%, while the average accuracy when using a combination of other features ranged between 58% and 73%. Conclusions The results show that the MFL and FD of a single channel sEMG recorded from the forearm can be used to accurately identify a set of finger and wrist flexions even when the muscle activity is very weak. A comparison with other features demonstrates that this feature set offers a dramatic improvement in the accuracy of identification of the wrist and finger movements. It is proposed that such a system could be used to control a prosthetic hand or for a human computer interface. PMID:20964863

Describing the brain in autism in five dimensions--magnetic resonance imaging-assisted diagnosis of autism spectrum disorder using a multiparameter classification approach.

PubMed

Ecker, Christine; Marquand, Andre; Mourão-Miranda, Janaina; Johnston, Patrick; Daly, Eileen M; Brammer, Michael J; Maltezos, Stefanos; Murphy, Clodagh M; Robertson, Dene; Williams, Steven C; Murphy, Declan G M

2010-08-11

Autism spectrum disorder (ASD) is a neurodevelopmental condition with multiple causes, comorbid conditions, and a wide range in the type and severity of symptoms expressed by different individuals. This makes the neuroanatomy of autism inherently difficult to describe. Here, we demonstrate how a multiparameter classification approach can be used to characterize the complex and subtle structural pattern of gray matter anatomy implicated in adults with ASD, and to reveal spatially distributed patterns of discriminating regions for a variety of parameters describing brain anatomy. A set of five morphological parameters including volumetric and geometric features at each spatial location on the cortical surface was used to discriminate between people with ASD and controls using a support vector machine (SVM) analytic approach, and to find a spatially distributed pattern of regions with maximal classification weights. On the basis of these patterns, SVM was able to identify individuals with ASD at a sensitivity and specificity of up to 90% and 80%, respectively. However, the ability of individual cortical features to discriminate between groups was highly variable, and the discriminating patterns of regions varied across parameters. The classification was specific to ASD rather than neurodevelopmental conditions in general (e.g., attention deficit hyperactivity disorder). Our results confirm the hypothesis that the neuroanatomy of autism is truly multidimensional, and affects multiple and most likely independent cortical features. The spatial patterns detected using SVM may help further exploration of the specific genetic and neuropathological underpinnings of ASD, and provide new insights into the most likely multifactorial etiology of the condition.

Effects of Participant Engagement on Prosodic Prominence

ERIC Educational Resources Information Center

Buxó-Lugo, Andrés; Toscano, Joseph C.; Watson, Duane G.

2018-01-01

It is generally assumed that prosodic cues that provide linguistic information, like discourse status, are driven primarily by the information structure of the conversation. This article investigates whether speakers have the capacity to adjust subtle acoustic-phonetic properties of the prosodic signal when they find themselves in contexts in…

Instructional Television: Do We Have the Courage to Succeed?

ERIC Educational Resources Information Center

Bosner, Paul

1976-01-01

A discussion of instructional television's implementation in terms of massiveness of the system; the decentralization of the system; and the fragmented, overlapping funding structure of the system, which results in obscured centers of power resting somewhere between state and local control, with subtle direction by the federal government.…

Cell Signaling and Neurotoxicity: Protein Kinase C in vitro and in vivo

EPA Science Inventory

There is a growing concern about the effects of chemicals on the developing nervous system. Chemical exposure at critical periods of development can be associated with effects ranging from subtle to profound on the structure and/or function of the nervous system. Understanding cr...

Non-Hydrostatic Modelling of Waves and Currents over Subtle Bathymetric Features

NASA Astrophysics Data System (ADS)

Gomes, E.; Mulligan, R. P.; McNinch, J.

2014-12-01

Localized areas with high rates of shoreline erosion on beaches, referred to as erosional hotspots, can occur near clusters of relict shore-oblique sandbars. Wave transformation and wave-driven currents over these morphological features could provide an understanding of the hydrodynamic-morphologic coupling mechanism that connects them to the occurrence of erosional hotspots. To investigate this, we use the non-hydrostatic SWASH model that phase-resolves the free surface and fluid motions throughout the water column, allowing for high resolution of wave propagation and breaking processes. In this study we apply a coupled system of nested models including SWAN over a large domain of the North Carolina shelf with smaller nested SWASH domains in areas of interest to determine the hydrodynamic processes occurring over shore oblique bars. In this presentation we focus on a high resolution grid (10 vertical layers, 10 m horizontal resolution) applied to the Duck region with model validation from acoustic wave and current data, and observations from the Coastal Lidar And Radar Imaging System (CLARIS). By altering the bathymetry input for each model run based on bathymetric surveys and comparing the predicted and observed wave heights and current profiles, the effects of subtle bathymetric perturbations have on wave refraction, wave breaking, surf zone currents and vorticity are investigated. The ability to predict wave breaking and hydrodynamics with a non-hydrostatic model may improve our understanding of surf zone dynamics in relation to morphologic conditions.

Weaver syndrome and EZH2 mutations: Clarifying the clinical phenotype.

PubMed

Tatton-Brown, Katrina; Murray, Anne; Hanks, Sandra; Douglas, Jenny; Armstrong, Ruth; Banka, Siddharth; Bird, Lynne M; Clericuzio, Carol L; Cormier-Daire, Valerie; Cushing, Tom; Flinter, Frances; Jacquemont, Marie-Line; Joss, Shelagh; Kinning, Esther; Lynch, Sally Ann; Magee, Alex; McConnell, Vivienne; Medeira, Ana; Ozono, Keiichi; Patton, Michael; Rankin, Julia; Shears, Debbie; Simon, Marleen; Splitt, Miranda; Strenger, Volker; Stuurman, Kyra; Taylor, Clare; Titheradge, Hannah; Van Maldergem, Lionel; Temple, I Karen; Cole, Trevor; Seal, Sheila; Rahman, Nazneen

2013-12-01

Weaver syndrome, first described in 1974, is characterized by tall stature, a typical facial appearance, and variable intellectual disability. In 2011, mutations in the histone methyltransferase, EZH2, were shown to cause Weaver syndrome. To date, we have identified 48 individuals with EZH2 mutations. The mutations were primarily missense mutations occurring throughout the gene, with some clustering in the SET domain (12/48). Truncating mutations were uncommon (4/48) and only identified in the final exon, after the SET domain. Through analyses of clinical data and facial photographs of EZH2 mutation-positive individuals, we have shown that the facial features can be subtle and the clinical diagnosis of Weaver syndrome is thus challenging, especially in older individuals. However, tall stature is very common, reported in >90% of affected individuals. Intellectual disability is also common, present in ~80%, but is highly variable and frequently mild. Additional clinical features which may help in stratifying individuals to EZH2 mutation testing include camptodactyly, soft, doughy skin, umbilical hernia, and a low, hoarse cry. Considerable phenotypic overlap between Sotos and Weaver syndromes is also evident. The identification of an EZH2 mutation can therefore provide an objective means of confirming a subtle presentation of Weaver syndrome and/or distinguishing Weaver and Sotos syndromes. As mutation testing becomes increasingly accessible and larger numbers of EZH2 mutation-positive individuals are identified, knowledge of the clinical spectrum and prognostic implications of EZH2 mutations should improve. © 2013 Wiley Periodicals, Inc.

Distal 22q11.2 microduplication encompassing the BCR gene.

PubMed

Descartes, Maria; Franklin, Judy; Diaz de Ståhl, Teresita; Piotrowski, Arkadiusz; Bruder, Carl E G; Dumanski, Jan P; Carroll, Andrew J; Mikhail, Fady M

2008-12-01

Chromosome 22 band q11.2 has been recognized to be highly susceptible to subtle microdeletions and microduplications, which have been attributed to the presence of several large segmental duplications; also known as low copy repeats (LCRs). These LCRs function as mediators of non-allelic homologous recombination (NAHR), which results in these chromosomal rearrangements as a result of unequal crossover. The four centromeric LCRs at proximal 22q11.2 have been previously implicated in recurrent chromosomal rearrangements including the DiGeorge/Velocardiofacial syndrome (DG/VCFs) microdeletion and its reciprocal microduplication. Recently, we and others have demonstrated that the four telomeric LCRs at distal 22q11.2 are causally implicated in a newly recognized recurrent distal 22q11.2 microdeletion syndrome in the region immediately telomeric to the DG/VCFs typically deleted region. Here we report on the clinical, cytogenetic, and array CGH studies of a 4.5-year-old girl with history of failure to thrive, developmental delay (DD), and relative macrocephaly. She carries a paternally inherited approximately 2.1 Mb microduplication at distal 22q11.2, which spans approximately 34 annotated genes, and is flanked by two of the four telomeric 22q11.2 LCRs. We conclude that the four telomeric LCRs at distal 22q11.2 can mediate both deletions and duplications in this genomic region. Both deletions and duplication of this region present with subtle clinical features including mild to moderate mental retardation, DD, and mild dysmorphic features. Copyright (c) 2008 Wiley-Liss, Inc.

Hydrothemal Alteration Mapping Using Feature-Oriented Principal Component Selection (fpcs) Method to Aster DATA:WIKKI and Mawulgo Thermal Springs, Yankari Park, Nigeria

NASA Astrophysics Data System (ADS)

Abubakar, A. J.; Hashim, M.; Pour, A. B.

2017-10-01

Geothermal systems are essentially associated with hydrothermal alteration mineral assemblages such as iron oxide/hydroxide, clay, sulfate, carbonate and silicate groups. Blind and fossilized geothermal systems are not characterized by obvious surface manifestations like hot springs, geysers and fumaroles, therefore, they could not be easily identifiable using conventional techniques. In this investigation, the applicability of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) were evaluated in discriminating hydrothermal alteration minerals associated with geothermal systems as a proxy in identifying subtle Geothermal systems at Yankari Park in northeastern Nigeria. The area is characterized by a number of thermal springs such as Wikki and Mawulgo. Feature-oriented Principal Component selection (FPCS) was applied to ASTER data based on spectral characteristics of hydrothermal alteration minerals for a systematic and selective extraction of the information of interest. Application of FPCS analysis to bands 5, 6 and 8 and bands 1, 2, 3 and 4 datasets of ASTER was used for mapping clay and iron oxide/hydroxide minerals in the zones of Wikki and Mawulgo thermal springs in Yankari Park area. Field survey using GPS and laboratory analysis, including X-ray Diffractometer (XRD) and Analytical Spectral Devices (ASD) were carried out to verify the image processing results. The results indicate that ASTER dataset reliably and complementarily be used for reconnaissance stage of targeting subtle alteration mineral assemblages associated with geothermal systems.

Distinctive Geomorphology of Gas Venting and Near Seafloor Gas Hydrate-Bearing sites

NASA Astrophysics Data System (ADS)

Paull, C. K.; Caress, D. W.; Lundsten, E.; Anderson, K.; Gwiazda, R.; McGann, M. L.; Edwards, B. D.; Riedel, M.; Herguera, J.

2012-12-01

High-resolution multibeam bathymetry and chirp seismic-reflection profiles collected with an Autonomous Underwater Vehicle (AUV) complimented by Remotely Operated Vehicle (ROV) observations and sampling reveal the fine scale geomorphology associated with gas venting and/or near subsurface gas hydrate accumulations along the Pacific North American continental margin (Santa Monica Basin, Hydrate Ridge, Eel River, Barkley Canyon, and Bullseye Vent) and along the transform faults in the Gulf of California. At the 1 m multibeam grid resolution of the new data, distinctive features and textures that are undetectable at lower resolution, show the impact of gas venting, gas hydrate development, and related phenomena on the seafloor morphology. Together a suite of geomorphic characteristics illustrates different stages in the development of seafloor gas venting systems. The more mature and/or impacted areas are associated with widespread exposures of methane-derived carbonates, which form broken and irregular seafloor pavements with karst-like voids in between the cemented blocks. These mature areas also contain elevated features >10 m high and circular seafloor craters with diameters of 3-50 m that appear to be associated with missing sections of the original seafloor. Smaller mound-like features (<10 m in diameter and 1-3 m higher than the surrounding seafloor) occur at multiple sites. Solid lenses of gas hydrate are occasionally exposed along fractures on the sides of these mounds and suggest that these are push-up features associated with gas hydrate growth within the near seafloor sediments. The youngest appearing features are associated with more-subtle (<3 m in diameter and ~0.5 m high) seafloor mounds, the crests of which are crossed with small cracks lined with white bacterial mats. ROV-collected (<1.5 m long) cores obtained from these subtle mounds encountered a hard layer at 30-60 cm sub-bottom. When this layer was penetrated, methane bubbles gushed out and continued to flow out for over an hour. These observations indicate that these small mounds are young features that trap considerable volumes of gas near the seafloor. Together these observations reveal the integrated effect that gas and/or gas hydrate occurrences can have on the seafloor. The existence of gaseous methane within ~1 m of the seafloor has intriguing implications as to the geo-hazard potential of such sites.

Biophysical Characterisation of Neuroglobin of the Icefish, a Natural Knockout for Hemoglobin and Myoglobin. Comparison with Human Neuroglobin

PubMed Central

Giordano, Daniela; Boron, Ignacio; Abbruzzetti, Stefania; Van Leuven, Wendy; Nicoletti, Francesco P.; Forti, Flavio; Bruno, Stefano; Cheng, C-H. Christina; Moens, Luc; di Prisco, Guido; Nadra, Alejandro D.; Estrin, Darío; Smulevich, Giulietta; Dewilde, Sylvia; Viappiani, Cristiano; Verde, Cinzia

2012-01-01

The Antarctic icefish Chaenocephalus aceratus lacks the globins common to most vertebrates, hemoglobin and myoglobin, but has retained neuroglobin in the brain. This conserved globin has been cloned, over-expressed and purified. To highlight similarities and differences, the structural features of the neuroglobin of this colourless-blooded fish were compared with those of the well characterised human neuroglobin as well as with the neuroglobin from the retina of the red blooded, hemoglobin and myoglobin-containing, closely related Antarctic notothenioid Dissostichus mawsoni. A detailed structural and functional analysis of the two Antarctic fish neuroglobins was carried out by UV-visible and Resonance Raman spectroscopies, molecular dynamics simulations and laser-flash photolysis. Similar to the human protein, Antarctic fish neuroglobins can reversibly bind oxygen and CO in the Fe2+ form, and show six-coordination by distal His in the absence of exogenous ligands. A very large and structured internal cavity, with discrete docking sites, was identified in the modelled three-dimensional structures of the Antarctic neuroglobins. Estimate of the free-energy barriers from laser-flash photolysis and Implicit Ligand Sampling showed that the cavities are accessible from the solvent in both proteins. Comparison of structural and functional properties suggests that the two Antarctic fish neuroglobins most likely preserved and possibly improved the function recently proposed for human neuroglobin in ligand multichemistry. Despite subtle differences, the adaptation of Antarctic fish neuroglobins does not seem to parallel the dramatic adaptation of the oxygen carrying globins, hemoglobin and myoglobin, in the same organisms. PMID:23226490

Structural Basis for Activation of Fatty Acid-binding Protein 4

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gillilan,R.; Ayers, S.; Noy, N.

2007-01-01

Fatty acid-binding protein 4 (FABP4) delivers ligands from the cytosol to the nuclear receptor PPAR{gamma} in the nucleus, thereby enhancing the transcriptional activity of the receptor. Notably, FABP4 binds multiple ligands with a similar affinity but its nuclear translocation is activated only by specific compounds. To gain insight into the structural features that underlie the ligand-specificity in activation of the nuclear import of FABP4, we solved the crystal structures of the protein complexed with two compounds that induce its nuclear translocation, and compared these to the apo-protein and to FABP4 structures bound to non-activating ligands. Examination of these structures indicatesmore » that activation coincides with closure of a portal loop phenylalanine side-chain, contraction of the binding pocket, a subtle shift in a helical domain containing the nuclear localization signal of the protein, and a resultant change in oligomeric state that exposes the nuclear localization signal to the solution. Comparisons of backbone displacements induced by activating ligands with a measure of mobility derived from translation, libration, screw (TLS) refinement, and with a composite of slowest normal modes of the apo state suggest that the helical motion associated with the activation of the protein is part of the repertoire of the equilibrium motions of the apo-protein, i.e. that ligand binding does not induce the activated configuration but serves to stabilize it. Nuclear import of FABP4 can thus be understood in terms of the pre-existing equilibrium hypothesis of ligand binding.« less

Physico-chemical properties and cytotoxic effects of sugar-based surfactants: Impact of structural variations.

PubMed

Lu, Biao; Vayssade, Muriel; Miao, Yong; Chagnault, Vincent; Grand, Eric; Wadouachi, Anne; Postel, Denis; Drelich, Audrey; Egles, Christophe; Pezron, Isabelle

2016-09-01

Surfactants derived from the biorefinery process can present interesting surface-active properties, low cytotoxicity, high biocompatibility and biodegradability. They are therefore considered as potential sustainable substitutes to currently used petroleum-based surfactants. To better understand and anticipate their performances, structure-property relationships need to be carefully investigated. For this reason, we applied a multidisciplinary approach to systematically explore the effect of subtle structural variations on both physico-chemical properties and biological effects. Four sugar-based surfactants, each with an eight carbon alkyl chain bound to a glucose or maltose head group by an amide linkage, were synthesized and evaluated together along with two commercially available standard surfactants. Physico-chemical properties including solubility, Krafft point, surface-tension lowering and critical micellar concentration (CMC) in water and biological medium were explored. Cytotoxicity evaluation by measuring proliferation index and metabolic activity against dermal fibroblasts showed that all surfactants studied may induce cell death at low concentrations (below their CMC). Results revealed significant differences in both physico-chemical properties and cytotoxic effects depending on molecule structural features, such as the position of the linkage on the sugar head-group, or the orientation of the amide linkage. Furthermore, the cytotoxic response increased with the reduction of surfactant CMC. This study underscores the relevance of a methodical and multidisciplinary approach that enables the consideration of surfactant solution properties when applied to biological materials. Overall, our results will contribute to a better understanding of the concomitant impact of surfactant structure at physico-chemical and biological levels. Copyright © 2016 Elsevier B.V. All rights reserved.

Empirical analysis of online social networks in the age of Web 2.0

NASA Astrophysics Data System (ADS)

Fu, Feng; Liu, Lianghuan; Wang, Long

2008-01-01

Today the World Wide Web is undergoing a subtle but profound shift to Web 2.0, to become more of a social web. The use of collaborative technologies such as blogs and social networking site (SNS) leads to instant online community in which people communicate rapidly and conveniently with each other. Moreover, there are growing interest and concern regarding the topological structure of these new online social networks. In this paper, we present empirical analysis of statistical properties of two important Chinese online social networks-a blogging network and an SNS open to college students. They are both emerging in the age of Web 2.0. We demonstrate that both networks possess small-world and scale-free features already observed in real-world and artificial networks. In addition, we investigate the distribution of topological distance. Furthermore, we study the correlations between degree (in/out) and degree (in/out), clustering coefficient and degree, popularity (in terms of number of page views) and in-degree (for the blogging network), respectively. We find that the blogging network shows disassortative mixing pattern, whereas the SNS network is an assortative one. Our research may help us to elucidate the self-organizing structural characteristics of these online social networks embedded in technical forms.

Mixing augmentation of transverse hydrogen jet by injection of micro air jets in supersonic crossflow

NASA Astrophysics Data System (ADS)

Anazadehsayed, A.; Barzegar Gerdroodbary, M.; Amini, Y.; Moradi, R.

2017-08-01

In this study, the influences of the micro air jet on the mixing of the sonic transverse hydrogen through micro-jets subjected to a supersonic crossflow are investigated. A three-dimensional numerical study has been performed to reveal the affects of micro air jet on mixing of the hydrogen jet in a Mach 4.0 crossflow with a global equivalence ratio of 0.5. Parametric studies were conducted on the various air jet conditions by using the Reynolds-averaged Navier-Stokes equations with Menter's Shear Stress Transport (SST) turbulence model. Complex jet interactions were found in the downstream region with a variety of flow features depending upon the angle of micro air jet. These flow features were found to have subtle effects on the mixing of hydrogen jets. Results indicate a different flow structure as air jet is presented in the downstream of the fuel jet. According to the results, without air, mixing occurs at a low rate. When the air jet is presented in the downstream of fuel jet, significant increase (up to 300%) occurs in the mixing performance of the hydrogen jet at downstream. In multi fuel jets, the mixing performance of the fuel jet is increased more than 200% when the micro air jet is injected. Consequently, an enhanced mixing zone occurs downstream of the injection slots which leads to flame-holding.

Observation versus classification in supervised category learning.

PubMed

Levering, Kimery R; Kurtz, Kenneth J

2015-02-01

The traditional supervised classification paradigm encourages learners to acquire only the knowledge needed to predict category membership (a discriminative approach). An alternative that aligns with important aspects of real-world concept formation is learning with a broader focus to acquire knowledge of the internal structure of each category (a generative approach). Our work addresses the impact of a particular component of the traditional classification task: the guess-and-correct cycle. We compare classification learning to a supervised observational learning task in which learners are shown labeled examples but make no classification response. The goals of this work sit at two levels: (1) testing for differences in the nature of the category representations that arise from two basic learning modes; and (2) evaluating the generative/discriminative continuum as a theoretical tool for understand learning modes and their outcomes. Specifically, we view the guess-and-correct cycle as consistent with a more discriminative approach and therefore expected it to lead to narrower category knowledge. Across two experiments, the observational mode led to greater sensitivity to distributional properties of features and correlations between features. We conclude that a relatively subtle procedural difference in supervised category learning substantially impacts what learners come to know about the categories. The results demonstrate the value of the generative/discriminative continuum as a tool for advancing the psychology of category learning and also provide a valuable constraint for formal models and associated theories.

Influence of disorder on the signature of the pseudogap and multigap superconducting behavior in FeSe

NASA Astrophysics Data System (ADS)

Rößler, Sahana; Huang, Chien-Lung; Jiao, Lin; Koz, Cevriye; Schwarz, Ulrich; Wirth, Steffen

2018-03-01

We investigated several FeSe single crystals grown by two different methods by utilizing experimental techniques, namely, resistivity, magnetoresistance, specific heat, scanning tunneling microscopy, and spectroscopy. The residual resistivity ratio (RRR) shows systematic differences between samples grown by chemical vapor transport and flux vapor transport, indicating variance in the amount of scattering centers. Although the superconducting transition temperature Tc is not directly related to RRR, our study evidences subtle differences in the features of an incipient ordering mode related to a depletion of density of states at the Fermi level. For instance, the onset temperature of anisotropic spin fluctuations at T*≈75 K, and the temperature of the opening up of a partial gap in the density of states at T**≈30 K, are not discernible in the samples with lower RRR. Further, we show that the functional dependence of the electronic specific heat below 2 K, which allows us to determine the nodal features as well as the small superconducting gap, differs significantly in crystals grown by these two different methods. Our investigation suggests that some of the controversies about the driving mechanism for the superconducting gap or its structure and symmetry are related to minute differences in the crystals arising due to the growth techniques used and the total amount of scattering centers present in the sample.

Deriving Quantitative Dynamics Information for Proteins and RNAs using ROTDIF with a Graphical User Interface

PubMed Central

Berlin, Konstantin; Longhini, Andrew; Dayie, T. Kwaku; Fushman, David

2013-01-01

To facilitate rigorous analysis of molecular motions in proteins, DNA, and RNA, we present a new version of ROTDIF, a program for determining the overall rotational diffusion tensor from single-or multiple-field Nuclear Magnetic Resonance (NMR) relaxation data. We introduce four major features that expand the program’s versatility and usability. The first feature is the ability to analyze, separately or together, 13C and/or 15N relaxation data collected at a single or multiple fields. A significant improvement in the accuracy compared to direct analysis of R2/R1 ratios, especially critical for analysis of 13C relaxation data, is achieved by subtracting high-frequency contributions to relaxation rates. The second new feature is an improved method for computing the rotational diffusion tensor in the presence of biased errors, such as large conformational exchange contributions, that significantly enhances the accuracy of the computation. The third new feature is the integration of the domain alignment and docking module for relaxation-based structure determination of multi-domain systems. Finally, to improve accessibility to all the program features, we introduced a graphical user interface (GUI) that simplifies and speeds up the analysis of the data. Written in Java, the new ROTDIF can run on virtually any computer platform. In addition, the new ROTDIF achieves an order of magnitude speedup over the previous version by implementing a more efficient deterministic minimization algorithm. We not only demonstrate the improvement in accuracy and speed of the new algorithm for synthetic and experimental 13C and 15N relaxation data for several proteins and nucleic acids, but also show that careful analysis required especially for characterizing RNA dynamics allowed us to uncover subtle conformational changes in RNA as a function of temperature that were opaque to previous analysis. PMID:24170368

The interactive role of subsynoptic scale jet sreak and planetary boundary layer adjustments in organizing an apparently isolated convective complex

NASA Technical Reports Server (NTRS)

Kaplan, M. L.; Zack, J. W.; Wong, V. C.; Tuccillo, J. J.; Coats, G. D.

1982-01-01

A mesoscale atmospheric simulation system is described that is being developed in order to improve the simulation of subsynoptic and mesoscale adjustments associated with cyclogenesis, severe storm development, and significant atmospheric transport processes. Present emphasis in model development is in the parameterization of physical processes, time-dependent boundary conditions, sophisticated initialization and analysis procedures, nested grid solutions, and applications software development. Basic characteristics of the system as of March 1982 are listed. In a case study, the Grand Island tornado outbreak of 3 June 1980 is considered in substantial detail. Results of simulations with a mesoscale atmospheric simulation system indicate that over the high plains subtle interactions between existing jet streaks and deep well mixed boundary layers can lead to well organized patterns of mesoscale divergence and pressure falls. The amplitude and positioning of these mesoscale features is a function of the subtle nonlinear interaction between the pre-existing jet-streak and deep well mixed boundary layers. Model results for the case study indicate that the model has the potential for forecasting the precursor mesoscale convective environment.

Halogenated Alkyltetrazoles for the Rational Design of FeII Spin-Crossover Materials: Fine-Tuning of the Ligand Size.

PubMed

Müller, Danny; Knoll, Christian; Seifried, Marco; Welch, Jan M; Giester, Gerald; Reissner, Michael; Weinberger, Peter

2018-04-06

1-(3-Halopropyl)-1H-tetrazoles and their corresponding Fe II spin-crossover complexes have been investigated in a combined experimental and theoretical study. Halogen substitution was found to positively influence the spin transition, shifting the transition temperature about 70 K towards room temperature. Halogens located at the ω position were found to be too far away from the coordinating tetrazole moiety to have an electronic impact on the spin transition. The subtle variation of the steric demand of the ligand in a highly comparable series was found to have a comparatively large impact on the spin-transition behavior, which highlights the sensitivity of the effect to subtle structural changes. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Water-Soluble Polyphosphazenes and Their Hydrogels

DTIC Science & Technology

1994-05-18

side groups, such as -OH, -COONa, -NH2, -NHCH3, -SO3", or -C=O, or amphiphilic units such as -OCH2CH20-, etc. High concentrations of hydrophilic side...soluble polymers since it allows a high degree of utilization of molecular design and either extensive or subtle structural manipulation. The third...advantages for development as water-soluble polymers or hydrogels. The backbone is hydrophilic, the chain structure has a high 3 degree of flexibility, and

Structure of the Reston ebolavirus VP30 C-terminal domain.

PubMed

Clifton, Matthew C; Kirchdoerfer, Robert N; Atkins, Kateri; Abendroth, Jan; Raymond, Amy; Grice, Rena; Barnes, Steve; Moen, Spencer; Lorimer, Don; Edwards, Thomas E; Myler, Peter J; Saphire, Erica Ollmann

2014-04-01

The ebolaviruses can cause severe hemorrhagic fever. Essential to the ebolavirus life cycle is the protein VP30, which serves as a transcriptional cofactor. Here, the crystal structure of the C-terminal, NP-binding domain of VP30 from Reston ebolavirus is presented. Reston VP30 and Ebola VP30 both form homodimers, but the dimeric interfaces are rotated relative to each other, suggesting subtle inherent differences or flexibility in the dimeric interface.

Accurate registration of temporal CT images for pulmonary nodules detection

NASA Astrophysics Data System (ADS)

Yan, Jichao; Jiang, Luan; Li, Qiang

2017-02-01

Interpretation of temporal CT images could help the radiologists to detect some subtle interval changes in the sequential examinations. The purpose of this study was to develop a fully automated scheme for accurate registration of temporal CT images for pulmonary nodule detection. Our method consisted of three major registration steps. Firstly, affine transformation was applied in the segmented lung region to obtain global coarse registration images. Secondly, B-splines based free-form deformation (FFD) was used to refine the coarse registration images. Thirdly, Demons algorithm was performed to align the feature points extracted from the registered images in the second step and the reference images. Our database consisted of 91 temporal CT cases obtained from Beijing 301 Hospital and Shanghai Changzheng Hospital. The preliminary results showed that approximately 96.7% cases could obtain accurate registration based on subjective observation. The subtraction images of the reference images and the rigid and non-rigid registered images could effectively remove the normal structures (i.e. blood vessels) and retain the abnormalities (i.e. pulmonary nodules). This would be useful for the screening of lung cancer in our future study.

Geologic applications of thermal-inertia mapping from satellite. [Powder River, Wyoming; Cubeza Prieta, Arizona, and Yellowstone National Park

NASA Technical Reports Server (NTRS)

Offield, T. W. (Principal Investigator); Watson, K.; Hummer-Miller, S.

1981-01-01

In the Powder River Basin, Wyo., narrow geologic units having thermal inertias which contrast with their surroundings can be discriminated in optimal images. A few subtle thermal inertia anomalies coincide with areas of helium leakage believed to be associated with deep oil and gas concentrations. The most important results involved delineation of tectonic framework elements some of which were not previously recognized. Thermal and thermal inertia images also permit mapping of geomorphic textural domains. A thermal lineament appears to reveal a basement discontinuity which involves the Homestake Mine in the Black Hill, a zone of Tertiary igneous activity and facies control in oil producing horizons. Applications of these data to the Cabeza Prieta, Ariz., area illustrate their potential for igneous rock type discrimination. Extension to Yellowstone National Park resulted in the detection of additional structural information but surface hydrothermal features could not be distinguished with any confidence. A thermal inertia mapping algorithm, a fast and accurate image registration technique, and an efficient topographic slope and elevation correction method were developed.

Different zinc(II) complex species and binding modes at Aβ N-terminus drive distinct long range cross-talks in the Aβ monomers.

PubMed

Pietropaolo, Adriana; Satriano, Cristina; Strano, Gaetano; La Mendola, Diego; Rizzarelli, Enrico

2015-12-01

The present study addresses the reconstruction of the free-energy landscapes of amyloid-beta1-42 (Aβ42) coordinated respectively with one and two zinc ions, to scrutinize whether different Aβ-zinc complex species, i.e., mononuclear and dinuclear metal complexes, induce different Aβ conformation features. We found a subtle switch of intramolecular interactions, depending both on the zinc coordination environment and on the peptide to zinc stoichiometric ratio. On the one side, hairpin-like structures are predominant in mononuclear complexes, where a salt-bridge that involves Lys28-Glu22 and Lys16-Asp23 is stabilized. On the other side, elongated conformations are instead stabilized in the dinuclear zinc complexes. Experimental studies of atomic force microscopy as well as of zinc-Aβ complex species distribution diagrams provide evidence that the theoretical calculations can be rationalized in terms of the correlation between the increased amount of amorphous aggregates and the Aβ/Zn(2+) ratio. Copyright © 2015 Elsevier Inc. All rights reserved.

Interstellar Polycyclic Aromatic Compounds and Astrophysics

NASA Technical Reports Server (NTRS)

Hodgins, Douglas M.; DeVincenzi, Donald (Technical Monitor)

1999-01-01

Polycyclic aromatic compounds (PACs), a class of organic molecules whose structures are characterized by the presence of two or more fused aromatic rings, have been the subject of astrophysical interest for nearly two decades. Large by interstellar standards (from as few as 20 to perhaps as many as several hundred atoms), it has been suggested that these species are among the most abundant interstellar molecules impacting a wide range of astrophysical phenomena including: the ubiquitous family of infrared emission bands observed in an ever-increasing assortment of astronomical objects; the subtle but rich array of discrete visible/near-infrared interstellar molecular absorption features known as the diffuse interstellar bands (DIBs); the broad near-infrared quasi-continuum observed in a number of nebulae known as excess red emission (ERE); the interstellar ultraviolet extinction curve and broad '2200 Angstrom bump'; the heating/cooling mechanisms of interstellar clouds. Nevertheless, until recently a lack of good-quality laboratory spectroscopic data on PACs under astrophysically relevant conditions (i.e. isolated, ionized molecules; ionized molecular clusters, etc.) has hindered critical evaluation and extension of this model

Quasiparticle recombination dynamics in the model cuprate superconductor HgBa2CuO4+δ

NASA Astrophysics Data System (ADS)

Hinton, J. P.; Thewalt, E.; Koralek, J. D.; Orenstein, J.; Barisic, N.; Xhao, X.; Chan, M.; Dorow, C.; Veit, M.; Ji, L.; Greven, M.

2014-03-01

The cuprate family of high temperature superconductors is characterized by a variety of electronic phases which emerge when charge carriers are added to the antiferromagnetic parent compound. The structural simplicity of the single layer cuprate system HgBa2CuO4+δ (Hg1201) is advantageous for experimentally detecting subtle features of these phases. In this work, we investigate the recombination dynamics of photo-excited quasiparticles in Hg1201 as a function of doping, temperature, and magnetic field using pump-probe optical reflectivity. We observe two distinct onset temperatures above TC in the underdoped part of the phase diagram, corresponding to T* and T** as observed in transport and neutron scattering experiments. We also measure a suppression of the recombination rate near TC which peaks at 8% hole concentration. We associate this suppression with coherence effects. Lastly, we observe a complex, non-monotonic temperature dependence in the dynamics around optimal doping, providing evidence for reentrant phase transitions near the apex of the superconducting dome. Work supported by DOE-BES

Synchronization in Random Pulse Oscillator Networks

NASA Astrophysics Data System (ADS)

Brown, Kevin; Hermundstad, Ann

Motivated by synchronization phenomena in neural systems, we study synchronization of random networks of coupled pulse oscillators. We begin by considering binomial random networks whose nodes have intrinsic linear dynamics. We quantify order in the network spiking dynamics using a new measure: the normalized Lev-Zimpel complexity (LZC) of the nodes' spike trains. Starting from a globally-synchronized state, we see two broad classes of behaviors. In one (''temporally random''), the LZC is high and nodes spike independently with no coherent pattern. In another (''temporally regular''), the network does not globally synchronize but instead forms coherent, repeating population firing patterns with low LZC. No topological feature of the network reliably predicts whether an individual network will show temporally random or regular behavior; however, we find evidence that degree heterogeneity in binomial networks has a strong effect on the resulting state. To confirm these findings, we generate random networks with independently-adjustable degree mean and variance. We find that the likelihood of temporally-random behavior increases as degree variance increases. Our results indicate the subtle and complex relationship between network structure and dynamics.

N-methyl-d-aspartate (NMDA) receptor antibodies encephalitis mimicking an autistic regression.

PubMed

Hacohen, Yael; Wright, Sukhvir; Gadian, Jonathan; Vincent, Angela; Lim, Ming; Wassmer, Evangeline; Lin, Jean-Pierre

2016-10-01

Expressive dysphasia and mutism are common clinical features in children and adults with N-methyl-d-aspartate receptor antibodies (NMDAR-Ab) encephalitis, and are likely to result from NMDAR hypofunction. A prodromal loss of social and communication skills can typify that of an autistic regression, particularly when presenting under the age of 3 years. Here we describe two toddlers who presented with developmental regression, particularly of their social communication skills, mimicking an autistic regression, who were found to have NMDAR-Ab in the serum and cerebrospinal fluid. Although both patients had some other neurological features, they were subtle, which resulted in delayed diagnosis of NMDAR-Ab encephalitis. Importantly, immunotherapy was beneficial in both patients, with significant improvement of their language skills and behaviour. © 2016 Mac Keith Press.

Weakly supervised classification in high energy physics

DOE PAGES

Dery, Lucio Mwinmaarong; Nachman, Benjamin; Rubbo, Francesco; ...

2017-05-01

As machine learning algorithms become increasingly sophisticated to exploit subtle features of the data, they often become more dependent on simulations. Here, this paper presents a new approach called weakly supervised classification in which class proportions are the only input into the machine learning algorithm. Using one of the most challenging binary classification tasks in high energy physics $-$ quark versus gluon tagging $-$ we show that weakly supervised classification can match the performance of fully supervised algorithms. Furthermore, by design, the new algorithm is insensitive to any mis-modeling of discriminating features in the data by the simulation. Weakly supervisedmore » classification is a general procedure that can be applied to a wide variety of learning problems to boost performance and robustness when detailed simulations are not reliable or not available.« less

ARC-1990-AC91-2014

NASA Image and Video Library

1990-02-14

Range : 1.7 million miles This photo of Venus was taken by the Galileo spacecraft's Solid State Imaging System. A high-pass spatial filter has been applied in order to emphasize the smaller-scale cloud features, and the rendition has been colorized to a bluish hue in order to emphasize the subtle contrasts in the cloud markings and to indicate how it was taken through a violet filter. The sulfuric acid clouds indicate considerable convective activity, in the equatorial regions of the planet to the left and downwind of the subsolar point (afternoon on Venus), They are analogous to 'fair weather clouds' on Earth. The filamentary dark features visible in the colorized image are here revealed to be composed of several dark nodules, like strings on a bead, each about 60 miles across.

Weakly supervised classification in high energy physics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dery, Lucio Mwinmaarong; Nachman, Benjamin; Rubbo, Francesco

As machine learning algorithms become increasingly sophisticated to exploit subtle features of the data, they often become more dependent on simulations. Here, this paper presents a new approach called weakly supervised classification in which class proportions are the only input into the machine learning algorithm. Using one of the most challenging binary classification tasks in high energy physics $-$ quark versus gluon tagging $-$ we show that weakly supervised classification can match the performance of fully supervised algorithms. Furthermore, by design, the new algorithm is insensitive to any mis-modeling of discriminating features in the data by the simulation. Weakly supervisedmore » classification is a general procedure that can be applied to a wide variety of learning problems to boost performance and robustness when detailed simulations are not reliable or not available.« less

Soccer in Indiana and models for non-leptonic decays of heavy flavours

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bigi, I.I.

1989-12-15

Various descriptions of non-leptonic charm decays are reviewed and their relative strengths and weaknesses are listed. I conclude that it is mainly (though no necessarily solely) a destructive interference in nonleptonic D{sup +} decays that shapes the decays of charm mesons. Some more subtle features in these decays are discussed in a preview of future research before I address the presently confused situation in D{sub s} decays. Finally I give a brief theoretical discussion of inclusive and exclusive non-leptonic decays of beauty mesons.

Idiosyncratic Findings in Trichoscopy of Tinea Capitis: Comma, Zigzag Hairs, Corkscrew, and Morse Code-like Hair

PubMed Central

Elghblawi, Ebtisam

2016-01-01

Dermoscopy is a method of growing significance in the diagnoses of dermatological pigmented skin diseases. However, in my case, mycology culture was negative and successful treatment was given on the basis of trichoscopy and wood lamp examination. I hereby describe a young boy with tinea capitis, multiple “comma hairs” and “zigzag hair” and a subtle additional feature “Morse code-like hair” when intensification was applied. Dermatoscopic aspects found skin Type 2 in a child of as a distinctive dermoscopic finding. PMID:28442876

Idiosyncratic Findings in Trichoscopy of Tinea Capitis: Comma, Zigzag Hairs, Corkscrew, and Morse Code-like Hair.

PubMed

Elghblawi, Ebtisam

2016-01-01

Dermoscopy is a method of growing significance in the diagnoses of dermatological pigmented skin diseases. However, in my case, mycology culture was negative and successful treatment was given on the basis of trichoscopy and wood lamp examination. I hereby describe a young boy with tinea capitis, multiple "comma hairs" and "zigzag hair" and a subtle additional feature "Morse code-like hair" when intensification was applied. Dermatoscopic aspects found skin Type 2 in a child of as a distinctive dermoscopic finding.

The evaluation of eye pain with a normal ocular exam.

PubMed

Lee, Andrew G; Brazis, Paul W

2003-12-01

Eye pain with or without associated head or face pain is a common complaint to the ophthalmologist. The ocular exam may reveal the etiology (e.g., corneal disease, angle closure glaucoma) but typically the exam is normal. This paper reviews the evaluation and management of eye pain with a "normal" ocular exam, including: 1) subtle findings on ocular exam; 2) transient findings on exam, and 3) no abnormal ocular findings. Ophthalmologists should be aware of the various etiologies for eye pain and the specific and distinctive features that make the diagnosis.

High-resolution crystal structures of Drosophila melanogaster angiotensin-converting enzyme in complex with novel inhibitors and antihypertensive drugs.

PubMed

Akif, Mohd; Georgiadis, Dimitris; Mahajan, Aman; Dive, Vincent; Sturrock, Edward D; Isaac, R Elwyn; Acharya, K Ravi

2010-07-16

Angiotensin I-converting enzyme (ACE), one of the central components of the renin-angiotensin system, is a key therapeutic target for the treatment of hypertension and cardiovascular disorders. Human somatic ACE (sACE) has two homologous domains (N and C). The N- and C-domain catalytic sites have different activities toward various substrates. Moreover, some of the undesirable side effects of the currently available and widely used ACE inhibitors may arise from their targeting both domains leading to defects in other pathways. In addition, structural studies have shown that although both these domains have much in common at the inhibitor binding site, there are significant differences and these are greater at the peptide binding sites than regions distal to the active site. As a model system, we have used an ACE homologue from Drosophila melanogaster (AnCE, a single domain protein with ACE activity) to study ACE inhibitor binding. In an extensive study, we present high-resolution structures for native AnCE and in complex with six known antihypertensive drugs, a novel C-domain sACE specific inhibitor, lisW-S, and two sACE domain-specific phosphinic peptidyl inhibitors, RXPA380 and RXP407 (i.e., nine structures). These structures show detailed binding features of the inhibitors and highlight subtle changes in the orientation of side chains at different binding pockets in the active site in comparison with the active site of N- and C-domains of sACE. This study provides information about the structure-activity relationships that could be utilized for designing new inhibitors with improved domain selectivity for sACE. 2010 Elsevier Ltd. All rights reserved.

Role of κ→λ light-chain constant-domain switch in the structure and functionality of A17 reactibody

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ponomarenko, Natalia; Chatziefthimiou, Spyros D.; Kurkova, Inna

2014-03-01

Catalytic antibody variants with κ and λ light-chain constant domains show differences in their crystal structures which lead to subtle changes in catalytic efficiency and thermodynamic parameters as well as in their affinity for peptide substrates. The engineering of catalytic function in antibodies requires precise information on their structure. Here, results are presented that show how the antibody domain structure affects its functionality. The previously designed organophosphate-metabolizing reactibody A17 has been re-engineered by replacing its constant κ light chain by the λ chain (A17λ), and the X-ray structure of A17λ has been determined at 1.95 Å resolution. It was foundmore » that compared with A17κ the active centre of A17λ is displaced, stabilized and made more rigid owing to interdomain interactions involving the CDR loops from the V{sub L} and V{sub H} domains. These V{sub L}/V{sub H} domains also have lower mobility, as deduced from the atomic displacement parameters of the crystal structure. The antibody elbow angle is decreased to 126° compared with 138° in A17κ. These structural differences account for the subtle changes in catalytic efficiency and thermodynamic parameters determined with two organophosphate ligands, as well as in the affinity for peptide substrates selected from a combinatorial cyclic peptide library, between the A17κ and A17λ variants. The data presented will be of interest and relevance to researchers dealing with the design of antibodies with tailor-made functions.« less

Correlation between temperature variations of static and dynamic properties in glass-forming liquids

DOE PAGES

Voylov, D. N.; Griffin, P. J.; Mercado, B.; ...

2016-12-29

In this detailed analysis of the static structure factor S(Q) in several glass-forming liquids we show that the temperature variations of the width of the main diffraction peak Q(T ) correlate with the fragility of these liquids. Our observation suggests a direct connection between rather subtle structural changes and sharp slowing down of structural relaxation in glass-forming liquids. We also show that this observation can be rationalized using the Adam-Gibbs approach, through a connection between temperature variations of structural correlation length, lc 2 /Q, and the size of cooperatively rearranging regions.

Effect of viroid infection on the dynamics of phenolic metabolites in the apoplast of tomato

USDA-ARS?s Scientific Manuscript database

Plants are capable of producing a wide array of secondary metabolites which serve many functions, due to their bioactive, redox or structural properties. Subtle changes in the external or internal environment can cause significant changes in the array of secondary metabolites presented in the tissu...

Accountable Game Design: Structuring the Dynamics of Student Learning Interactions

ERIC Educational Resources Information Center

Charoenying, Timothy

2010-01-01

Game-based classroom activity is intended to leverage students' interest and motivation to play, and to provide safe contexts for supporting students' academic learning. However, a basic criticism of many games currently used in classroom settings is that they can fail to meaningfully embody academic content. A more subtle concern is that…

A Change in Seasons: Increasing Student Observation Skills

ERIC Educational Resources Information Center

Sterling, Donna R.

2006-01-01

Using the seasons in the science classroom increases student observation skills as they focus on subtle differences such as shades of color and differences in structures. In this article, the author presents a variety of activities that can help students identify and demonstrate patterns and changes in leaf or plant development. The ability to…

Relative Sizes of Organic Molecules

NASA Technical Reports Server (NTRS)

2000-01-01

This computer graphic depicts the relative complexity of crystallizing large proteins in order to study their structures through x-ray crystallography. Insulin is a vital protein whose structure has several subtle points that scientists are still trying to determine. Large molecules such as insuline are complex with structures that are comparatively difficult to understand. For comparison, a sugar molecule (which many people have grown as hard crystals in science glass) and a water molecule are shown. These images were produced with the Macmolecule program. Photo credit: NASA/Marshall Space Flight Center (MSFC)

A new approach to the characterization of subtle errors in everyday action: implications for mild cognitive impairment.

PubMed

Seligman, Sarah C; Giovannetti, Tania; Sestito, John; Libon, David J

2014-01-01

Mild functional difficulties have been associated with early cognitive decline in older adults and increased risk for conversion to dementia in mild cognitive impairment, but our understanding of this decline has been limited by a dearth of objective methods. This study evaluated the reliability and validity of a new system to code subtle errors on an established performance-based measure of everyday action and described preliminary findings within the context of a theoretical model of action disruption. Here 45 older adults completed the Naturalistic Action Test (NAT) and neuropsychological measures. NAT performance was coded for overt errors, and subtle action difficulties were scored using a novel coding system. An inter-rater reliability coefficient was calculated. Validity of the coding system was assessed using a repeated-measures ANOVA with NAT task (simple versus complex) and error type (overt versus subtle) as within-group factors. Correlation/regression analyses were conducted among overt NAT errors, subtle NAT errors, and neuropsychological variables. The coding of subtle action errors was reliable and valid, and episodic memory breakdown predicted subtle action disruption. Results suggest that the NAT can be useful in objectively assessing subtle functional decline. Treatments targeting episodic memory may be most effective in addressing early functional impairment in older age.

Extending Halogen-based Medicinal Chemistry to Proteins: IODO-INSULIN AS A CASE STUDY.

PubMed

El Hage, Krystel; Pandyarajan, Vijay; Phillips, Nelson B; Smith, Brian J; Menting, John G; Whittaker, Jonathan; Lawrence, Michael C; Meuwly, Markus; Weiss, Michael A

2016-12-30

Insulin, a protein critical for metabolic homeostasis, provides a classical model for protein design with application to human health. Recent efforts to improve its pharmaceutical formulation demonstrated that iodination of a conserved tyrosine (Tyr B26 ) enhances key properties of a rapid-acting clinical analog. Moreover, the broad utility of halogens in medicinal chemistry has motivated the use of hybrid quantum- and molecular-mechanical methods to study proteins. Here, we (i) undertook quantitative atomistic simulations of 3-[iodo-Tyr B26 ]insulin to predict its structural features, and (ii) tested these predictions by X-ray crystallography. Using an electrostatic model of the modified aromatic ring based on quantum chemistry, the calculations suggested that the analog, as a dimer and hexamer, exhibits subtle differences in aromatic-aromatic interactions at the dimer interface. Aromatic rings (Tyr B16 , Phe B24 , Phe B25 , 3-I-Tyr B26 , and their symmetry-related mates) at this interface adjust to enable packing of the hydrophobic iodine atoms within the core of each monomer. Strikingly, these features were observed in the crystal structure of a 3-[iodo-Tyr B26 ]insulin analog (determined as an R 6 zinc hexamer). Given that residues B24-B30 detach from the core on receptor binding, the environment of 3-I-Tyr B26 in a receptor complex must differ from that in the free hormone. Based on the recent structure of a "micro-receptor" complex, we predict that 3-I-Tyr B26 engages the receptor via directional halogen bonding and halogen-directed hydrogen bonding as follows: favorable electrostatic interactions exploiting, respectively, the halogen's electron-deficient σ-hole and electronegative equatorial band. Inspired by quantum chemistry and molecular dynamics, such "halogen engineering" promises to extend principles of medicinal chemistry to proteins. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

F429 Regulation of Tunnels in Cytochrome P450 2B4: A Top Down Study of Multiple Molecular Dynamics Simulations

PubMed Central

Mancini, Giordano; Zazza, Costantino

2015-01-01

The root causes of the outcomes of the single-site mutation in enzymes remain by and large not well understood. This is the case of the F429H mutant of the cytochrome P450 (CYP) 2B4 enzyme where the substitution, on the proximal surface of the active site, of a conserved phenylalanine 429 residue with histidine seems to hamper the formation of the active species, Compound I (porphyrin cation radical-Fe(IV) = O, Cpd I) from the ferric hydroperoxo (Fe(III)OOH-, Cpd 0) precursor. Here we report a study based on extensive molecular dynamic (MD) simulations of 4 CYP-2B4 point mutations compared to the WT enzyme, having the goal of better clarifying the importance of the proximal Phe429 residue on CYP 2B4 catalytic properties. To consolidate the huge amount of data coming from five simulations and extract the most distinct structural features of the five species studied we made an extensive use of cluster analysis. The results show that all studied single polymorphisms of F429, with different side chain properties: i) drastically alter the reservoir of conformations accessible by the protein, perturbing global dynamics ii) expose the thiolate group of residue Cys436 to the solvent, altering the electronic properties of Cpd0 and iii) affect the various ingress and egress channels connecting the distal sites with the bulk environment, altering the reversibility of these channels. In particular, it was observed that the wild type enzyme exhibits unique structural features as compared to all mutant species in terms of weak interactions (hydrogen bonds) that generate a completely different dynamical behavior of the complete system. Albeit not conclusive, the current computational investigation sheds some light on the subtle and critical effects that proximal single-site mutations can exert on the functional mechanisms of human microsomal CYPs which should go rather far beyond local structure characterization. PMID:26415031

F429 Regulation of Tunnels in Cytochrome P450 2B4: A Top Down Study of Multiple Molecular Dynamics Simulations.

PubMed

Mancini, Giordano; Zazza, Costantino

2015-01-01

The root causes of the outcomes of the single-site mutation in enzymes remain by and large not well understood. This is the case of the F429H mutant of the cytochrome P450 (CYP) 2B4 enzyme where the substitution, on the proximal surface of the active site, of a conserved phenylalanine 429 residue with histidine seems to hamper the formation of the active species, Compound I (porphyrin cation radical-Fe(IV) = O, Cpd I) from the ferric hydroperoxo (Fe(III)OOH-, Cpd 0) precursor. Here we report a study based on extensive molecular dynamic (MD) simulations of 4 CYP-2B4 point mutations compared to the WT enzyme, having the goal of better clarifying the importance of the proximal Phe429 residue on CYP 2B4 catalytic properties. To consolidate the huge amount of data coming from five simulations and extract the most distinct structural features of the five species studied we made an extensive use of cluster analysis. The results show that all studied single polymorphisms of F429, with different side chain properties: i) drastically alter the reservoir of conformations accessible by the protein, perturbing global dynamics ii) expose the thiolate group of residue Cys436 to the solvent, altering the electronic properties of Cpd0 and iii) affect the various ingress and egress channels connecting the distal sites with the bulk environment, altering the reversibility of these channels. In particular, it was observed that the wild type enzyme exhibits unique structural features as compared to all mutant species in terms of weak interactions (hydrogen bonds) that generate a completely different dynamical behavior of the complete system. Albeit not conclusive, the current computational investigation sheds some light on the subtle and critical effects that proximal single-site mutations can exert on the functional mechanisms of human microsomal CYPs which should go rather far beyond local structure characterization.

A Top-down versus a Bottom-up Hidden-variables Description of the Stern-Gerlach Experiment

NASA Astrophysics Data System (ADS)

Arsenijević, M.; Jeknić-Dugić, J.; Dugić, M.

We employ the Stern-Gerlach experiment to highlight the basics of a minimalist, non-interpretational top-down approach to quantum foundations. Certain benefits of the "quantum structural studies" (QSS) highlightedhere are detected and discussed. While the top-down approach can be described without making any reference to the fundamental structure of a closed system, the hidden variables (HV) theory á la Bohm proves to be more subtle than it is typically regarded.

Evidence for population bottlenecks and subtle genetic structure in the yellow rail

USGS Publications Warehouse

Popper, Kenneth J.; Miller, Leonard F.; Green, Michael; Haig, Susan M.; Mullins, Thomas D.

2012-01-01

The Yellow Rail (Coturnicops noveboracencis) is among the most enigmatic and least studied North American birds. Nesting exclusively in marshes and wetlands, it breeds largely east of the Rocky Mountains in the northern United States and Canada, but there is an isolated population in southern Oregon once believed extirpated. The degree of connectivity of the Oregon population with the main population is unknown. We used mitochondrial DNA sequences (mtDNA) and six microsatellite loci to characterize the Yellow Rail's genetic structure and diversity patterns in six areas. Our mtDNA-based analyses of genetic structure identified significant population differentiation, but pairwise comparison of regions identified no clear geographic trends. In contrast, microsatellites suggested subtle genetic structure differentiating the Oregon population from those in the five regions sampled in the Yellow Rail's main breeding range. The genetic diversity of the Oregon population was also the lowest of the six regions sampled, and Oregon was one of three regions that demonstrated evidence of recent population bottlenecks. Factors that produced population reductions may include loss of wetlands to development and agricultural conversion, drought, and wildfire. At this time, we are unable to determine if the high percentage (50%) of populations having experienced bottlenecks is representative of the Yellow Rail's entire range. Further genetic data from additional breeding populations will be required for this issue to be addressed.

Probing the electronic and local structural changes across the pressure-induced insulator-to-metal transition in VO2

NASA Astrophysics Data System (ADS)

Marini, C.; Bendele, M.; Joseph, B.; Kantor, I.; Mitrano, M.; Mathon, O.; Baldini, M.; Malavasi, L.; Pascarelli, S.; Postorino, P.

2014-11-01

Local and electronic structures of vanadium in \\text{VO}2 are studied across the high-pressure insulator-to-metal (IMT) transition using V K-edge x-ray absorption spectroscopy. Unlike the temperature-induced IMT, pressure-induced metallization leads to only subtle changes in the V K-edge prepeak structure, indicating a different mechanism involving smaller electronic spectral weight transfer close to the chemical potential. Intriguingly, upon application of the hydrostatic pressure, the electronic structure begins to show substantial changes well before the occurrence of the IMT and the associated structural transition to an anisotropic compression of the monoclinic metallic phase.

Brainstem Involvement as a Cause of Central Sleep Apnea: Pattern of Microstructural Cerebral Damage in Patients with Cerebral Microangiopathy

PubMed Central

Duning, Thomas; Deppe, Michael; Brand, Eva; Stypmann, Jörg; Becht, Charlotte; Heidbreder, Anna; Young, Peter

2013-01-01

Background The exact underlying pathomechanism of central sleep apnea with Cheyne-Stokes respiration (CSA-CSR) is still unclear. Recent studies have demonstrated an association between cerebral white matter changes and CSA. A dysfunction of central respiratory control centers in the brainstem was suggested by some authors. Novel MR-imaging analysis tools now allow far more subtle assessment of microstructural cerebral changes. The aim of this study was to investigate whether and what severity of subtle structural cerebral changes could lead to CSA-CSR, and whether there is a specific pattern of neurodegenerative changes that cause CSR. Therefore, we examined patients with Fabry disease (FD), an inherited, lysosomal storage disease. White matter lesions are early and frequent findings in FD. Thus, FD can serve as a "model disease" of cerebral microangiopathy to study in more detail the impact of cerebral lesions on central sleep apnea. Patients and Methods Genetically proven FD patients (n = 23) and age-matched healthy controls (n = 44) underwent a cardio-respiratory polysomnography and brain MRI at 3.0 Tesla. We applied different MR-imaging techniques, ranging from semiquantitative measurement of white matter lesion (WML) volumes and automated calculation of brain tissue volumes to VBM of gray matter and voxel-based diffusion tensor imaging (DTI) analysis. Results In 5 of 23 Fabry patients (22%) CSA-CSR was detected. Voxel-based DTI analysis revealed widespread structural changes in FD patients when compared to the healthy controls. When calculated as a separate group, DTI changes of CSA-CSR patients were most prominent in the brainstem. Voxel-based regression analysis revealed a significant association between CSR severity and microstructural DTI changes within the brainstem. Conclusion Subtle microstructural changes in the brainstem might be a neuroanatomical correlate of CSA-CSR in patients at risk of WML. DTI is more sensitive and specific than conventional structural MRI and other advanced MR analyses tools in demonstrating these abnormalities. PMID:23637744

Structural Characterization of Missense Mutations Using High Resolution Mass Spectrometry: A Case Study of the Parkinson's-Related Protein, DJ-1

NASA Astrophysics Data System (ADS)

Ben-Nissan, Gili; Chotiner, Almog; Tarnavsky, Mark; Sharon, Michal

2016-06-01

Missense mutations that lead to the expression of mutant proteins carrying single amino acid substitutions are the cause of numerous diseases. Unlike gene lesions, insertions, deletions, nonsense mutations, or modified RNA splicing, which affect the length of a polypeptide, or determine whether a polypeptide is translated at all, missense mutations exert more subtle effects on protein structure, which are often difficult to evaluate. Here, we took advantage of the spectral resolution afforded by the EMR Orbitrap platform, to generate a mass spectrometry-based approach relying on simultaneous measurements of the wild-type protein and the missense variants. This approach not only considerably shortens the analysis time due to the concurrent acquisition but, more importantly, enables direct comparisons between the wild-type protein and the variants, allowing identification of even subtle structural changes. We demonstrate our approach using the Parkinson's-associated protein, DJ-1. Together with the wild-type protein, we examined two missense mutants, DJ-1A104T and DJ-1D149A, which lead to early-onset familial Parkinson's disease. Gas-phase, thermal, and chemical stability assays indicate clear alterations in the conformational stability of the two mutants: the structural stability of DJ-1D149A is reduced, whereas that of DJ-1A104T is enhanced. Overall, we anticipate that the methodology presented here will be applicable to numerous other missense mutants, promoting the structural investigations of multiple variants of the same protein.

The nature of inherent bactericidal activity: insights from the nanotopology of three species of dragonfly

NASA Astrophysics Data System (ADS)

Mainwaring, David E.; Nguyen, Song Ha; Webb, Hayden; Jakubov, Timur; Tobin, Mark; Lamb, Robert N.; Wu, Alex H.-F.; Marchant, Richard; Crawford, Russell J.; Ivanova, Elena P.

2016-03-01

While insect wings are widely recognised as multi-functional, recent work showed that this extends to extensive bactericidal activity brought about by cell deformation and lysis on the wing nanotopology. We now quantitatively show that subtle changes to this topography result in substantial changes in bactericidal activity that are able to span an order of magnitude. Notably, the chemical composition of the lipid nanopillars was seen by XPS and synchrotron FTIR microspectroscopy to be similar across these activity differences. Modelling the interaction between bacterial cells and the wing surface lipids of 3 species of dragonflies, that inhabit similar environments, but with distinctly different behavioural repertoires, provided the relationship between surface structure and antibacterial functionality. In doing so, these principal behavioural patterns correlated with the demands for antimicrobial efficiency dictated by differences in their foraging strategies. This work now reveals a new feature in the design elegance of natural multi-functional surfaces as well providing insights into the bactericidal mechanism underlying inherently antimicrobial materials, while suggesting that nanotopology is related to the evolutionary development of a species through the demands of its behavioural repertoire. The underlying relationship between the processes of wetting, adhesion and capillarity of the lipid nanopillars and bactericidal efficiency suggests new prospects for purely mechano-responsive antibacterial surfaces.While insect wings are widely recognised as multi-functional, recent work showed that this extends to extensive bactericidal activity brought about by cell deformation and lysis on the wing nanotopology. We now quantitatively show that subtle changes to this topography result in substantial changes in bactericidal activity that are able to span an order of magnitude. Notably, the chemical composition of the lipid nanopillars was seen by XPS and synchrotron FTIR microspectroscopy to be similar across these activity differences. Modelling the interaction between bacterial cells and the wing surface lipids of 3 species of dragonflies, that inhabit similar environments, but with distinctly different behavioural repertoires, provided the relationship between surface structure and antibacterial functionality. In doing so, these principal behavioural patterns correlated with the demands for antimicrobial efficiency dictated by differences in their foraging strategies. This work now reveals a new feature in the design elegance of natural multi-functional surfaces as well providing insights into the bactericidal mechanism underlying inherently antimicrobial materials, while suggesting that nanotopology is related to the evolutionary development of a species through the demands of its behavioural repertoire. The underlying relationship between the processes of wetting, adhesion and capillarity of the lipid nanopillars and bactericidal efficiency suggests new prospects for purely mechano-responsive antibacterial surfaces. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr08542j

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Seyong; Vetter, Jeffrey S

Computer architecture experts expect that non-volatile memory (NVM) hierarchies will play a more significant role in future systems including mobile, enterprise, and HPC architectures. With this expectation in mind, we present NVL-C: a novel programming system that facilitates the efficient and correct programming of NVM main memory systems. The NVL-C programming abstraction extends C with a small set of intuitive language features that target NVM main memory, and can be combined directly with traditional C memory model features for DRAM. We have designed these new features to enable compiler analyses and run-time checks that can improve performance and guard againstmore » a number of subtle programming errors, which, when left uncorrected, can corrupt NVM-stored data. Moreover, to enable recovery of data across application or system failures, these NVL-C features include a flexible directive for specifying NVM transactions. So that our implementation might be extended to other compiler front ends and languages, the majority of our compiler analyses are implemented in an extended version of LLVM's intermediate representation (LLVM IR). We evaluate NVL-C on a number of applications to show its flexibility, performance, and correctness.« less

Integrated circuit authentication using photon-limited x-ray microscopy.

PubMed

Markman, Adam; Javidi, Bahram

2016-07-15

A counterfeit integrated circuit (IC) may contain subtle changes to its circuit configuration. These changes may be observed when imaged using an x-ray; however, the energy from the x-ray can potentially damage the IC. We have investigated a technique to authenticate ICs under photon-limited x-ray imaging. We modeled an x-ray image with lower energy by generating a photon-limited image from a real x-ray image using a weighted photon-counting method. We performed feature extraction on the image using the speeded-up robust features (SURF) algorithm. We then authenticated the IC by comparing the SURF features to a database of SURF features from authentic and counterfeit ICs. Our experimental results with real and counterfeit ICs using an x-ray microscope demonstrate that we can correctly authenticate an IC image captured using orders of magnitude lower energy x-rays. To the best of our knowledge, this Letter is the first one on using a photon-counting x-ray imaging model and relevant algorithms to authenticate ICs to prevent potential damage.

Dysfunction in GABA signalling mediates autism-like stereotypies and Rett syndrome phenotypes.

PubMed

Chao, Hsiao-Tuan; Chen, Hongmei; Samaco, Rodney C; Xue, Mingshan; Chahrour, Maria; Yoo, Jong; Neul, Jeffrey L; Gong, Shiaoching; Lu, Hui-Chen; Heintz, Nathaniel; Ekker, Marc; Rubenstein, John L R; Noebels, Jeffrey L; Rosenmund, Christian; Zoghbi, Huda Y

2010-11-11

Mutations in the X-linked MECP2 gene, which encodes the transcriptional regulator methyl-CpG-binding protein 2 (MeCP2), cause Rett syndrome and several neurodevelopmental disorders including cognitive disorders, autism, juvenile-onset schizophrenia and encephalopathy with early lethality. Rett syndrome is characterized by apparently normal early development followed by regression, motor abnormalities, seizures and features of autism, especially stereotyped behaviours. The mechanisms mediating these features are poorly understood. Here we show that mice lacking Mecp2 from GABA (γ-aminobutyric acid)-releasing neurons recapitulate numerous Rett syndrome and autistic features, including repetitive behaviours. Loss of MeCP2 from a subset of forebrain GABAergic neurons also recapitulates many features of Rett syndrome. MeCP2-deficient GABAergic neurons show reduced inhibitory quantal size, consistent with a presynaptic reduction in glutamic acid decarboxylase 1 (Gad1) and glutamic acid decarboxylase 2 (Gad2) levels, and GABA immunoreactivity. These data demonstrate that MeCP2 is critical for normal function of GABA-releasing neurons and that subtle dysfunction of GABAergic neurons contributes to numerous neuropsychiatric phenotypes.

Hyperspectral Image Enhancement and Mixture Deep-Learning Classification of Corneal Epithelium Injuries.

PubMed

Noor, Siti Salwa Md; Michael, Kaleena; Marshall, Stephen; Ren, Jinchang

2017-11-16

In our preliminary study, the reflectance signatures obtained from hyperspectral imaging (HSI) of normal and abnormal corneal epithelium tissues of porcine show similar morphology with subtle differences. Here we present image enhancement algorithms that can be used to improve the interpretability of data into clinically relevant information to facilitate diagnostics. A total of 25 corneal epithelium images without the application of eye staining were used. Three image feature extraction approaches were applied for image classification: (i) image feature classification from histogram using a support vector machine with a Gaussian radial basis function (SVM-GRBF); (ii) physical image feature classification using deep-learning Convolutional Neural Networks (CNNs) only; and (iii) the combined classification of CNNs and SVM-Linear. The performance results indicate that our chosen image features from the histogram and length-scale parameter were able to classify with up to 100% accuracy; particularly, at CNNs and CNNs-SVM, by employing 80% of the data sample for training and 20% for testing. Thus, in the assessment of corneal epithelium injuries, HSI has high potential as a method that could surpass current technologies regarding speed, objectivity, and reliability.

Acoustic foundations of the speech-to-song illusion.

PubMed

Tierney, Adam; Patel, Aniruddh D; Breen, Mara

2018-06-01

In the "speech-to-song illusion," certain spoken phrases are heard as highly song-like when isolated from context and repeated. This phenomenon occurs to a greater degree for some stimuli than for others, suggesting that particular cues prompt listeners to perceive a spoken phrase as song. Here we investigated the nature of these cues across four experiments. In Experiment 1, participants were asked to rate how song-like spoken phrases were after each of eight repetitions. Initial ratings were correlated with the consistency of an underlying beat and within-syllable pitch slope, while rating change was linked to beat consistency, within-syllable pitch slope, and melodic structure. In Experiment 2, the within-syllable pitch slope of the stimuli was manipulated, and this manipulation changed the extent to which participants heard certain stimuli as more musical than others. In Experiment 3, the extent to which the pitch sequences of a phrase fit a computational model of melodic structure was altered, but this manipulation did not have a significant effect on musicality ratings. In Experiment 4, the consistency of intersyllable timing was manipulated, but this manipulation did not have an effect on the change in perceived musicality after repetition. Our methods provide a new way of studying the causal role of specific acoustic features in the speech-to-song illusion via subtle acoustic manipulations of speech, and show that listeners can rapidly (and implicitly) assess the degree to which nonmusical stimuli contain musical structure. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Pelagic Life and Depth: Coastal Physical Features in West Africa Shape the Genetic Structure of the Bonga Shad, Ethmalosa fimbriata

PubMed Central

Durand, Jean-Dominique; Guinand, Bruno; Dodson, Julian J.; Lecomte, Frédéric

2013-01-01

The bonga shad, Ethmalosa fimbriata, is a West African pelagic species still abundant in most habitats of its distribution range and thought to be only recently affected by anthropogenic pressure (habitat destruction or fishing pressure). Its presence in a wide range of coastal habitats characterised by different hydrodynamic processes, represents a case study useful for evaluating the importance of physical structure of the west African shoreline on the genetic structure of a small pelagic species. To investigate this question, the genetic diversity of E. fimbriata was assessed at both regional and species range scales, using mitochondrial (mt) and nuclear DNA markers. Whereas only three panmictic units were identified with mtDNA at the large spatial scale, nuclear genetic markers (EPIC: exon-primed intron-crossing) indicated a more complex genetic pattern at the regional scale. In the northern-most section of shad’s distribution range, up to 4 distinct units were identified. Bayesian inference as well as spatial autocorrelation methods provided evidence that gene flow is impeded by the presence of deep-water areas near the coastline (restricting the width of the coastal shelf), such as the Cap Timiris and the Kayar canyons in Mauritania and Senegal, respectively. The added discriminatory power provided by the use of EPIC markers proved to be essential to detect the influence of more subtle, contemporary processes (e.g. gene flow, barriers, etc.) acting within the glacial refuges identified previously by mtDNA. PMID:24130890

Cryptoblemes: A New Discovery with Major Economic Implications and Profound Changes to the Geologic Paradigm

NASA Technical Reports Server (NTRS)

Windolph, J., Jr.; Sutton, J.

1997-01-01

Cryptoblemes are subtle impact shock signatures imprinted by cosmic debris on the crustal surfaces of lunar planetary bodes. These signatures constitute a complex cumulative overprinting of topographic, structural geophysical, and tectonic patterns that have a conspicuous radial centric multiringed symmetry. The geometry and distribution of cryptoblemes on Earth is comparable to the size and density of impact features on lunar planetary surfaces. Analysis of satellite imagery, sea-floor sonar, side-looking radar and aerial photographs of specific sites reveals new criteria for the identification and confirmation of impact-shock signatures. These criteria include joint and foliation patterns with asbestiform minerals, ribbon-quartz, spheroidal weathering, domal exfoliation, pencil shale, and shock spheres, which may originate from hydrocavitation of water-saturated sedimentary rocks. Cryptoblemes may also be associated with breccia pipes, sinkholes, buttes, mesas, and bogs, high-Rn anomalies, nodular concentrations, and earthquake epicenters. Major implications of cryptobleme identification include exploratory targeting of hydrocarbon and mineral deposits and the explanation of their origins. Analysis of known mineral deposits, structural traps and sedimentary basins show a direct correlation with cryptobleme patterns. Significant geologic paradigm shifts related to cryptoblemes include mountain building processes, structural orogenies, induced volcanism, earthquake origins, hydrocarbon diagenesis, formation mineral deposits, continental rifting, and plate movements, magnetic overprinting and local regional, and global geologic extinction and speciation patterns. Two figures provide a comparison between a multiring impact overprint in water and multiring cryptobleme in the U.S. basin range. (Additional information is contained in the original document).

In search of actionable targets for agrigenomics and microalgal biofuel production: sequence-structural diversity studies on algal and higher plants with a focus on GPAT protein.

PubMed

Misra, Namrata; Panda, Prasanna Kumar

2013-04-01

The triacylglycerol (TAG) pathway provides several targets for genetic engineering to optimize microalgal lipid productivity. GPAT (glycerol-3-phosphate acyltransferase) is a crucial enzyme that catalyzes the initial step of TAG biosynthesis. Despite many recent biochemical studies, a comprehensive sequence-structure analysis of GPAT across diverse lipid-yielding organisms is lacking. Hence, we performed a comparative genomic analysis of plastid-located GPAT proteins from 7 microalgae and 3 higher plants species. The close evolutionary relationship observed between red algae/diatoms and green algae/plant lineages in the phylogenetic tree were further corroborated by motif and gene structure analysis. The predicted molecular weight, amino acid composition, Instability Index, and hydropathicity profile gave an overall representation of the biochemical features of GPAT protein across the species under study. Furthermore, homology models of GPAT from Chlamydomonas reinhardtii, Arabidopsis thaliana, and Glycine max provided deep insights into the protein architecture and substrate binding sites. Despite low sequence identity found between algal and plant GPATs, the developed models exhibited strikingly conserved topology consisting of 14α helices and 9β sheets arranged in two domains. However, subtle variations in amino acids of fatty acyl binding site were identified that might influence the substrate selectivity of GPAT. Together, the results will provide useful resources to understand the functional and evolutionary relationship of GPAT and potentially benefit in development of engineered enzyme for augmenting algal biofuel production.

Structural Optimization of a Force Balance Using a Computational Experiment Design

NASA Technical Reports Server (NTRS)

Parker, P. A.; DeLoach, R.

2002-01-01

This paper proposes a new approach to force balance structural optimization featuring a computational experiment design. Currently, this multi-dimensional design process requires the designer to perform a simplification by executing parameter studies on a small subset of design variables. This one-factor-at-a-time approach varies a single variable while holding all others at a constant level. Consequently, subtle interactions among the design variables, which can be exploited to achieve the design objectives, are undetected. The proposed method combines Modern Design of Experiments techniques to direct the exploration of the multi-dimensional design space, and a finite element analysis code to generate the experimental data. To efficiently search for an optimum combination of design variables and minimize the computational resources, a sequential design strategy was employed. Experimental results from the optimization of a non-traditional force balance measurement section are presented. An approach to overcome the unique problems associated with the simultaneous optimization of multiple response criteria is described. A quantitative single-point design procedure that reflects the designer's subjective impression of the relative importance of various design objectives, and a graphical multi-response optimization procedure that provides further insights into available tradeoffs among competing design objectives are illustrated. The proposed method enhances the intuition and experience of the designer by providing new perspectives on the relationships between the design variables and the competing design objectives providing a systematic foundation for advancements in structural design.

Mammographic density measured as changes in tissue structure caused by HRT

NASA Astrophysics Data System (ADS)

Raundahl, Jakob; Loog, Marco; Nielsen, Mads

2006-03-01

Numerous studies have investigated the relation between mammographic density and breast cancer risk. These studies indicate that women with high breast density have a four to six fold risk increase. An investigation of whether or not this relation is causal is important for, e.g., hormone replacement therapy (HRT), which has been shown to actually increase the density. No gold standard for automatic assessment of mammographic density exists. Manual methods such as Wolfe patterns and BI-RADS are helpful for communication of diagnostic sensitivity, but they are both time consuming and crude. They may be sufficient in certain cases and for single measurements, but for serial, temporal analysis it is necessary to be able to detect more subtle changes and, in addition, to be more reproducible. In this work an automated method for measuring the effect of HRT w.r.t. changes in biological density in the breast is presented. This measure is a novel measure, which provides structural information orthogonal to intensity-based methods. Hessian eigenvalues at different scales are used as features and a clustering of these is employed to divide a mammogram into four structurally different areas. Subsequently, based on the relative size of the areas, a density score is determined. In the experiments, two sets of mammograms of 50 patients from a double blind, placebo controlled HRT experiment were used. The change in density for the HRT group, measured with the new method, was significantly higher (p = 0.0002) than the change in the control group.

Defect Structures of La1 - y Sr y F3 - y , La1 - y Ba y F3 - y , and Nd1 - y Ca y F3 - y ( y = 0.05, 0.10) Nonstoichiometric Tysonite Phases

NASA Astrophysics Data System (ADS)

Chernaya, T. S.; Verin, I. A.; Khrykina, O. N.; Bolotina, N. B.

2018-01-01

Characteristic features of defect structures of La1 - y Sr y F3 - y , La1 - y Ba y F3 - y , and Nd1 - y Ca y F3 - y ( y = 0.05, 0.10) nonstoichiometric phases of different compositions are determined from X-ray diffraction data. Interest in subtle details of their structure is determined by the possibility of ion transport over fluorine vacancies and by a strong compositional dependence of the ionic conductivity. The La0.95Sr0.05F2.95, La0.95Ba0.05F2.95, and Nd0.95Ca0.05F2.95 phases, as well as the La0.9Ba0.1F2.9 phase, crystallize as β-LaF3 (sp. gr. P3̅c1, Z = 6). The La0.9Sr0.1F2.9 and Nd0.9Ca0.1F2.9 phases lose their superstructure and are described by a cell whose volume is three times smaller (sp. gr. P63/ mmc, Z = 2). Defects of crystal structure R1 - y M y F3 - y are not exhausted by vacancies in fluorine positions. All crystals with a "large" cell are twinned according to the merohedral twin law. The majority of atomic positions in models with a "small" cell are split by group symmetry elements and are occupied statistically.

Analysis of renal anomalies in VACTERL association.

PubMed

Cunningham, Bridget K; Khromykh, Alina; Martinez, Ariel F; Carney, Tyler; Hadley, Donald W; Solomon, Benjamin D

2014-10-01

VACTERL association refers to a combination of congenital anomalies that can include: vertebral anomalies, anal atresia, cardiac malformations, tracheo-esophageal fistula with esophageal atresia, renal anomalies (typically structural renal anomalies), and limb anomalies. We conducted a description of a case series to characterize renal findings in a cohort of patients with VACTERL association. Out of the overall cohort, 48 patients (with at least three component features of VACTERL and who had abdominal ultrasound performed) met criteria for analysis. Four other patients were additionally analyzed separately, with the hypothesis that subtle renal system anomalies may occur in patients who would not otherwise meet criteria for VACTERL association. Thirty-three (69%) of the 48 patients had a clinical manifestation affecting the renal system. The most common renal manifestation (RM) was vesicoureteral reflux (VUR) in addition to a structural defect (present in 27%), followed by unilateral renal agenesis (24%), and then dysplastic/multicystic kidneys or duplicated collected system (18% for each). Twenty-two (88%) of the 25 patients with a structural RM had an associated anorectal malformation. Individuals with either isolated lower anatomic anomalies, or both upper and lower anatomic anomalies were not statistically more likely to have a structural renal defect than those with isolated upper anatomic anomalies (p = 0.22, p = 0.284, respectively). Given the high prevalence of isolated VUR in our cohort, we recommend a screening VCUG or other imaging modality be obtained to evaluate for VUR if initial renal ultrasound shows evidence of obstruction or renal scarring, as well as ongoing evaluation of renal health. © 2014 Wiley Periodicals, Inc.

Crystal structure and RNA-binding properties of an Hfq homolog from the deep-branching Aquificae: conservation of the lateral RNA-binding mode

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stanek, Kimberly A.; Patterson-West, Jennifer; Randolph, Peter S.

The host factor Hfq, as the bacterial branch of the Sm family, is an RNA-binding protein involved in the post-transcriptional regulation of mRNA expression and turnover. Hfq facilitates pairing between small regulatory RNAs (sRNAs) and their corresponding mRNA targets by binding both RNAs and bringing them into close proximity. Hfq homologs self-assemble into homo-hexameric rings with at least two distinct surfaces that bind RNA. Recently, another binding site, dubbed the `lateral rim', has been implicated in sRNA·mRNA annealing; the RNA-binding properties of this site appear to be rather subtle, and its degree of evolutionary conservation is unknown. An Hfq homologmore » has been identified in the phylogenetically deep-branching thermophileAquifex aeolicus(Aae), but little is known about the structure and function of Hfq from basal bacterial lineages such as the Aquificae. Therefore,AaeHfq was cloned, overexpressed, purified, crystallized and biochemically characterized. Structures ofAaeHfq were determined in space groupsP1 andP6, both to 1.5 Å resolution, and nanomolar-scale binding affinities for uridine- and adenosine-rich RNAs were discovered. Co-crystallization with U 6RNA reveals that the outer rim of theAaeHfq hexamer features a well defined binding pocket that is selective for uracil. ThisAaeHfq structure, combined with biochemical and biophysical characterization of the homolog, reveals deep evolutionary conservation of the lateral RNA-binding mode, and lays a foundation for further studies of Hfq-associated RNA biology in ancient bacterial phyla.« less

Habitat characteristics of polar bear terrestrial maternal den sites in northern Alaska

USGS Publications Warehouse

Durner, George M.; Amstrup, Steven C.; Fischbach, Anthony S.

2003-01-01

Polar bears (Ursus maritimus) give birth to and nurture their young in dens of ice and snow. During 1999-2001, we measured the structure of 22 dens on the coastal plain of northern Alaska after polar bear families had evacuated their dens in the spring. During the summers of 2001 and 2002, we revisited the sites of 42 maternal and autumn exploratory dens and recorded characteristics of the under-snow habitat. The structure of polar bear snow dens was highly variable. Most were simple chambers with a single entrance/egress tunnel. Others had multiple chambers and additional tunnels. Thickness of snow above and below dens was highly variable, but most dens were overlain by less than 1 m of snow. Dens were located on, or associated with, pronounced landscape features (primarily coastal and river banks, but also a lake shore and an abandoned oil field gravel pad) that are readily distinguished from the surrounding terrain in summer and catch snow in early winter. Although easily identified, den landforms in northern Alaska were more subtle than den habitats in many other parts of the Arctic. The structure of polar bear dens in Alaska was strikingly similar to that of dens elsewhere and has remained largely unchanged in northern Alaska for more than 25 years. Knowledge of den structure and site characteristics will allow resource managers to identify habitats with the greatest probability of holding dens. This information may assist resource managers in preventing negative impacts of mineral exploration and extraction on polar bears.

Space Shuttle Radar Images of Terrestrial Impact Structures: SIR-C/X-SAR

NASA Astrophysics Data System (ADS)

McHone, J. F.; Blumberg, D. G.; Greeley, R.; Underwood, J. R., Jr.

1995-09-01

The Spaceborne Radar Laboratory (SRL) orbited Earth in April and October of 1994 operating two imaging radars: X-SAR, an X-band (3 cm lambda) instrument, and the polarimetric SIR-C, a combination L-band/C-band (24 cm and 5.6 cm lambda). More than 150 terrestrial meteorite craters and astroblemes are presently known. Three of these, Wolfe Creek in Australia; Roter Kamm in Namibia; and Zhamanshin in Kazakhstan, were planned targets and were imaged successfully with multiple passes and look directions. Several other impact sites were fortuitously imaged while radar data were being collected for other purposes. These sites include B.P. and Oasis structures in Libya, Aourounga multi-ring feature in Chad, Amguid crater in Algeria, and the Spider astrobleme and Henbury crater field in Australia. Wolfe Creek (19 degrees 10'S; 127 degrees 47'E; 875 m dia) Both the elevated rim and the inner floor of this crater appear as radar bright features. Strong radar returns are due to blocky rubble textures in the rim and desert vegetation within the central bowl. Associated linear sand dunes show differential penetration properties in the various radar wavelengths and polarization. Roter Kamm (27 degrees 46'S; 016 degrees 18'E; 2.5 km dia) This bowl-shaped crater is mostly buried by wind-blown sands. Comparison of differential radar penetration patterns due to changes in wavelength and look direction reveal concealed target rocks and a buried possible ejecta unit. Zhamanshin (48 degrees 24'N; 060 degrees 48'E; 14 km dia) This unusual impact structure, first detected by the presence of glassy impact melt products [1], has very little topographic relief and is nearly invisible on survey-quality radar imagery. Fully processed images, however, enhance subtle vegetation patterns which highlight regional streams. These drainage patterns are now being analyzed in detail to better delineate boundaries and internal structure of this feature. B.P. Structure (25 degrees 19'N; 024 degrees 20'E; 2.8 km dia) Wind-blown sands which cover much of this relatively small feature make it difficult to distinguish from numerous dark sandstone outcrops using only optical images. Radar, however, penetrates the shallow sand mantle to reveal a nearly complete radar-bright bullseye pattern typical of central-uplift style impact structure. Oasis Structure (24 degrees 35'N; 24 degrees 24'E; >11.5 km dia) Oasis astrobleme was originally described as an elevated ring of sandstone some 5.1 km wide in desert sands. Examination of optical satellite images detected subtle concentric patterns more than 11 km across [2]. SIR-C images reveal strong arcuate reflectors buried beneath the sand at an even larger diameter of greater than 17 km. Aurounga (19 degrees 06'N; 019 degrees 15'E; 12.6 km dia) Although this highly circular depression has been noticed in numerous remote sensing studies, eg.[3], it usually has been associated with a large volcanic field and attributed to endogenic forces. Recent reports of shatter cones [4] and microscopic shock metamorphic effects [5] now demonstrate an impact origin. The radar-dark ring is a sand-filled trough which interupts a regional pattern of yardangs, wind-cut parallel ridges and grooves, developed in surrounding sandstones. Amguid (26 degrees 05'N; 004 degrees 23'E; 450 m dia) Situated in elevated rocky highlands [6], the small Amguid crater is nearly overprinted by surrounding radar backscatter. A dry central bowl is partially filled with smoothly surfaced fine-grained playa deposits which absorb radar energy and/or reflect it away from the spacecraft. The result is a distinct radar-dark disk within a bright regional ground clutter. Spider (16 degrees 44'S; 126 degrees 05'E; 13 km dia) Named for a radially splayed fault system in its center, Spider is the exposed root structure of a central-uplift impact feature [7]. Radar slope effects on processed data clearly delineate its size and internal complexity. Henbury craters (24 degrees 35'S; 133 degrees 09'E; largest ca.150 m dia) Although quite small, Henbury crater field [8] appears distinctly radar bright on survey -qualilty imagery. Strong radar backscatter may be due to a combination of impact-disrupted sedimentary horizons and of soil dielectrical properties altered by a significant meteoritic iron content [9]. References: [1] Garvin J. B. and Schnetzler C. C. (1994) GSA Spec. Pap. 293, 249-257. [2] Dietz R. S. and McHone J. F. (1979) Apollo Soyuz Test Proj. Summary Sci. Rept. (2) NASA SP-412, 183-192. [3] Roland N. W. (1976) Geol. Jahrb., Reihe A, 33, 117-131. [4] Becq-Giraudon J. F. et al. (1992) Comptes Rendus de l'Academ. des Sciences, Ser.2, 315, 83-88. [5] Grieve R. A. F. and Therriault A. M. (1995) LPS XXVI, 515-516. [6] Lambert P. et al. (1980) Meteoritics, 15, 157-159. [7] Harms et al. (1980) Nature, 286, 704-706. [8] Milton D. J. (1968) Geol. Surv. Prof. Pap. 599-C, C1-C16. [9] Hodge P. W. and Wright F. W. (1971) JGR, 76, 3880-3895.

Brain structural changes and their correlation with vascular disease in type 2 diabetes mellitus patients: a voxel-based morphometric study.

PubMed

Wang, Chunxia; Fu, Kailiang; Liu, Huaijun; Xing, Fei; Zhang, Songyun

2014-08-15

Voxel-based morphometry has been used in the study of alterations in brain structure in type 1 diabetes mellitus patients. These changes are associated with clinical indices. The age at onset, pathogenesis, and treatment of type 1 diabetes mellitus are different from those for type 2 diabetes mellitus. Thus, type 1 and type 2 diabetes mellitus may have different impacts on brain structure. Only a few studies of the alterations in brain structure in type 2 diabetes mellitus patients using voxel-based morphometry have been conducted, with inconsistent results. We detected subtle changes in the brain structure of 23 cases of type 2 diabetes mellitus, and demonstrated that there was no significant difference between the total volume of gray and white matter of the brain of type 2 diabetes mellitus patients and that in controls. Regional atrophy of gray matter mainly occurred in the right temporal and left occipital cortex, while regional atrophy of white matter involved the right temporal lobe and the right cerebellar hemisphere. The ankle-brachial index in patients with type 2 diabetes mellitus strongly correlated with the volume of brain regions in the default mode network. The ankle-brachial index, followed by the level of glycosylated hemoglobin, most strongly correlated with the volume of gray matter in the right temporal lobe. These data suggest that voxel-based morphometry could detect small structural changes in patients with type 2 diabetes mellitus. Early macrovascular atherosclerosis may play a crucial role in subtle brain atrophy in type 2 diabetes mellitus patients, with chronic hyperglycemia playing a lesser role.

Subtle In-Scanner Motion Biases Automated Measurement of Brain Anatomy From In Vivo MRI

PubMed Central

Alexander-Bloch, Aaron; Clasen, Liv; Stockman, Michael; Ronan, Lisa; Lalonde, Francois; Giedd, Jay; Raznahan, Armin

2016-01-01

While the potential for small amounts of motion in functional magnetic resonance imaging (fMRI) scans to bias the results of functional neuroimaging studies is well appreciated, the impact of in-scanner motion on morphological analysis of structural MRI is relatively under-studied. Even among “good quality” structural scans, there may be systematic effects of motion on measures of brain morphometry. In the present study, the subjects’ tendency to move during fMRI scans, acquired in the same scanning sessions as their structural scans, yielded a reliable, continuous estimate of in-scanner motion. Using this approach within a sample of 127 children, adolescents, and young adults, significant relationships were found between this measure and estimates of cortical gray matter volume and mean curvature, as well as trend-level relationships with cortical thickness. Specifically, cortical volume and thickness decreased with greater motion, and mean curvature increased. These effects of subtle motion were anatomically heterogeneous, were present across different automated imaging pipelines, showed convergent validity with effects of frank motion assessed in a separate sample of 274 scans, and could be demonstrated in both pediatric and adult populations. Thus, using different motion assays in two large non-overlapping sets of structural MRI scans, convergent evidence showed that in-scanner motion—even at levels which do not manifest in visible motion artifact—can lead to systematic and regionally specific biases in anatomical estimation. These findings have special relevance to structural neuroimaging in developmental and clinical datasets, and inform ongoing efforts to optimize neuroanatomical analysis of existing and future structural MRI datasets in non-sedated humans. PMID:27004471

Transport properties of electrons in fractal magnetic-barrier structures

NASA Astrophysics Data System (ADS)

Sun, Lifeng; Fang, Chao; Guo, Yong

2010-09-01

Quantum transport properties in fractal magnetically modulated structures are studied by the transfer-matrix method. It is found that the transmission spectra depend sensitively not only on the incident energy and the direction of the wave vector but also on the stage of the fractal structures. Resonance splitting, enhancement, and position shift of the resonance peaks under different magnetic modulation are observed at four different fractal stages, and the relationship between the conductance in the fractal structure and magnetic modulation is also revealed. The results indicate the spectra of the transmission can be considered as fingerprints for the fractal structures, which show the subtle correspondence between magnetic structures and transport behaviors.

Subtle pathological changes in neocortical temporal lobe epilepsy.

PubMed

Ochoa, Juan G; Hentgarden, Diana; Paulzak, Audrey; Ogden, Melissa; Pryson, Richard; Lamle, Markus; Rusyniak, Walter G

2017-06-01

This was a prospective observational study to correlate the clinical symptoms, electrophysiology, imaging, and surgical pathology of patients with temporal lobe epilepsy (TLE) without hippocampal sclerosis. We selected consecutive patients with TLE and normal MRI undergoing temporal lobe resection between April and September 2015. Clinical features, imaging, and functional data were reviewed. Intracranial monitoring and language mapping were performed when it was required according to our team recommendation. Prior to hippocampal resection, intraoperative electrocorticography was performed using depth electrodes in the amygdala and the hippocampus. The resected hippocampus was sent for pathological analysis. Five patients with diagnosis with non-lesional TLE were included. We did not find distinctive clinical features that could be a characteristic of non-lesional TLE. The mean follow-up was 13.2months (11-15months); 80% of patients achieved Engel Class I outcome. There was no distinctive electrographic findings in these patients. Histopathologic analysis was negative for mesial temporal sclerosis. A second blinded independent neuropathologist with expertise in epilepsy found ILAE type I focal cortical dysplasia in the parahippocampal gyrus in all patients. A third independent neuropathologist reported changes in layer 2 with larger pyramidal neurons in 4 cases but concluded that none of these cases met the diagnostic criteria of FCD. Subtle pathological changes could be associated with a parahippocampal epileptic zone and should be investigated in patients with MRI-negative TLE. This study also highlights the lack of interobserver reliability for the diagnosis of mild cortical dysplasia. Finally, selective amygdalo-hippocampectomy or laser ablation of the hippocampus may not control intractable epilepsy in this specific population. Copyright © 2017 Elsevier Inc. All rights reserved.

Dystonia and Tremor: The Clinical Syndromes with Isolated Tremor

PubMed Central

Albanese, Alberto; Sorbo, Francesca Del

2016-01-01

Background Dystonia and tremor share many commonalities. Isolated tremor is part of the phenomenological spectrum of isolated dystonia and of essential tremor. The occurrence of subtle features of dystonia may allow one to differentiate dystonic tremor from essential tremor. Diagnostic uncertainty is enhanced when no features of dystonia are found in patients with a tremor syndrome, raising the question whether the observed phenomenology is an incomplete form of dystonia. Methods Known forms of syndromes with isolated tremor are reviewed. Diagnostic uncertainties between tremor and dystonia are put into perspective. Results The following isolated tremor syndromes are reviewed: essential tremor, head tremor, voice tremor, jaw tremor, and upper-limb tremor. Their varied phenomenology is analyzed and appraised in the light of a possible relationship with dystonia. Discussion Clinicians making a diagnosis of isolated tremor should remain vigilant for the detection of features of dystonia. This is in keeping with the recent view that isolated tremor may be an incomplete phenomenology of dystonia. PMID:27152246

Evaluation of handwriting kinematics and pressure for differential diagnosis of Parkinson's disease.

PubMed

Drotár, Peter; Mekyska, Jiří; Rektorová, Irena; Masarová, Lucia; Smékal, Zdeněk; Faundez-Zanuy, Marcos

2016-02-01

We present the PaHaW Parkinson's disease handwriting database, consisting of handwriting samples from Parkinson's disease (PD) patients and healthy controls. Our goal is to show that kinematic features and pressure features in handwriting can be used for the differential diagnosis of PD. The database contains records from 37 PD patients and 38 healthy controls performing eight different handwriting tasks. The tasks include drawing an Archimedean spiral, repetitively writing orthographically simple syllables and words, and writing of a sentence. In addition to the conventional kinematic features related to the dynamics of handwriting, we investigated new pressure features based on the pressure exerted on the writing surface. To discriminate between PD patients and healthy subjects, three different classifiers were compared: K-nearest neighbors (K-NN), ensemble AdaBoost classifier, and support vector machines (SVM). For predicting PD based on kinematic and pressure features of handwriting, the best performing model was SVM with classification accuracy of Pacc=81.3% (sensitivity Psen=87.4% and specificity of Pspe=80.9%). When evaluated separately, pressure features proved to be relevant for PD diagnosis, yielding Pacc=82.5% compared to Pacc=75.4% using kinematic features. Experimental results showed that an analysis of kinematic and pressure features during handwriting can help assess subtle characteristics of handwriting and discriminate between PD patients and healthy controls. Copyright © 2016 Elsevier B.V. All rights reserved.

Deficits in hippocampal-dependent transfer generalization learning accompany synaptic dysfunction in a mouse model of amyloidosis.

PubMed

Montgomery, Karienn S; Edwards, George; Levites, Yona; Kumar, Ashok; Myers, Catherine E; Gluck, Mark A; Setlow, Barry; Bizon, Jennifer L

2016-04-01

Elevated β-amyloid and impaired synaptic function in hippocampus are among the earliest manifestations of Alzheimer's disease (AD). Most cognitive assessments employed in both humans and animal models, however, are insensitive to this early disease pathology. One critical aspect of hippocampal function is its role in episodic memory, which involves the binding of temporally coincident sensory information (e.g., sights, smells, and sounds) to create a representation of a specific learning epoch. Flexible associations can be formed among these distinct sensory stimuli that enable the "transfer" of new learning across a wide variety of contexts. The current studies employed a mouse analog of an associative "transfer learning" task that has previously been used to identify risk for prodromal AD in humans. The rodent version of the task assesses the transfer of learning about stimulus features relevant to a food reward across a series of compound discrimination problems. The relevant feature that predicts the food reward is unchanged across problems, but an irrelevant feature (i.e., the context) is altered. Experiment 1 demonstrated that C57BL6/J mice with bilateral ibotenic acid lesions of hippocampus were able to discriminate between two stimuli on par with control mice; however, lesioned mice were unable to transfer or apply this learning to new problem configurations. Experiment 2 used the APPswe PS1 mouse model of amyloidosis to show that robust impairments in transfer learning are evident in mice with subtle β-amyloid-induced synaptic deficits in the hippocampus. Finally, Experiment 3 confirmed that the same transfer learning impairments observed in APPswePS1 mice were also evident in the Tg-SwDI mouse, a second model of amyloidosis. Together, these data show that the ability to generalize learned associations to new contexts is disrupted even in the presence of subtle hippocampal dysfunction and suggest that, across species, this aspect of hippocampal-dependent learning may be useful for early identification of AD-like pathology. © 2015 Wiley Periodicals, Inc.

Failure to thrive as primary feature in two patients with subtle chromosomal aneuploidy: Interstitial deletion 2q33

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grace, K.; Mulla, W.; Stump, T.

1994-09-01

It is well known that patients with chromosomal aneuploidy present with multiple congenital anomalies and dysmorphia, and that they may have associated failure to thrive. However, rarely is failure to thrive the predominant presenting feature. We report two such patients. Patient 1 had a marked history of failure to thrive, (weight 50% for 5 1/2 months at 20 months, length 50% for 15 months at 20 months). Patient 2 was noted to be growth retarded at 2 months upon presenting to the hospital with respiratory symptoms (weight 50% for a newborn, length 50% for 36 weeks gestation). There was relativemore » head sparing in both patients. Chromosome analysis in patient 1, prompted by a negative work-up for the failure to thrive, and emerging evidence of developmental delay, revealed a 46,XY,del(2)(q32.2q33) karyotype. Chromosome analysis in patient 2, done as part of a complete workup for the failure to thrive, revealed a 46,XX,del(2)(q33.2q33.2 or q33.2q33.3) karyotype. On careful examination, subtle dysmorphic features were seen. In both patients these included a long flat philtrum, thin upper lip and high arched palate. Patient 1 also had a small posterior cleft of the palate. These patients have the smallest interstitial deletions of chromosome 2 so far reported. Their deletions overlap within 2q33 although they are not identical. Review of the literature reveals 15 patients with interstitial deletions which include 2q33. Marked growth retardation is reported in 14 of these cases. Cleft palate/abnormal uvula were frequently associated. These cases illustrate the need to include high resolution chromosomal studies as part of a complete work-up for unexplained failure to thrive.« less

Deficits in hippocampal-dependent transfer generalization learning accompany synaptic dysfunction in a mouse model of amyloidosis

PubMed Central

Montgomery, Karienn S.; Edwards, George; Levites, Yona; Kumar, Ashok; Myers, Catherine E.; Gluck, Mark A.; Setlow, Barry; Bizon, Jennifer L.

2015-01-01

Elevated β-amyloid and impaired synaptic function in hippocampus are among the earliest manifestations of Alzheimer’s disease (AD). Most cognitive assessments employed in both humans and animal models, however, are insensitive to this early disease pathology. One critical aspect of hippocampal function is its role in episodic memory, which involves the binding of temporally coincident sensory information (e.g., sights, smells, and sounds) to create a representation of a specific learning epoch. Flexible associations can be formed among these distinct sensory stimuli that enable the “transfer” of new learning across a wide variety of contexts. The current studies employed a mouse analog of an associative “transfer learning” task that has previously been used to identify risk for prodromal AD in humans. The rodent version of the task assesses the transfer of learning about stimulus features relevant to a food reward across a series of compound discrimination problems. The relevant feature that predicts the food reward is unchanged across problems, but an irrelevant feature (i.e., the context) is altered. Experiment 1 demonstrated that C57BL6/J mice with bilateral ibotenic acid lesions of hippocampus were able to discriminate between two stimuli on par with control mice; however, lesioned mice were unable to transfer or apply this learning to new problem configurations. Experiment 2 used the APPswePS1 mouse model of amyloidosis to show that robust impairments in transfer learning are evident in mice with subtle β amyloid-induced synaptic deficits in the hippocampus. Finally, Experiment 3 confirmed that the same transfer learning impairments observed in APPswePS1 mice were also evident in the Tg-SwDI mouse, a second model of amyloidosis. Together, these data show that the ability to generalize learned associations to new contexts is disrupted even in the presence of subtle hippocampal dysfunction and suggest that, across species, this aspect of hippocampal-dependent learning may be useful for early identification of AD-like pathology. PMID:26418152

Computerized detection of lung nodules by means of "virtual dual-energy" radiography.

PubMed

Chen, Sheng; Suzuki, Kenji

2013-02-01

Major challenges in current computer-aided detection (CADe) schemes for nodule detection in chest radiographs (CXRs) are to detect nodules that overlap with ribs and/or clavicles and to reduce the frequent false positives (FPs) caused by ribs. Detection of such nodules by a CADe scheme is very important, because radiologists are likely to miss such subtle nodules. Our purpose in this study was to develop a CADe scheme with improved sensitivity and specificity by use of "virtual dual-energy" (VDE) CXRs where ribs and clavicles are suppressed with massive-training artificial neural networks (MTANNs). To reduce rib-induced FPs and detect nodules overlapping with ribs, we incorporated the VDE technology in our CADe scheme. The VDE technology suppressed rib and clavicle opacities in CXRs while maintaining soft-tissue opacity by use of the MTANN technique that had been trained with real dual-energy imaging. Our scheme detected nodule candidates on VDE images by use of a morphologic filtering technique. Sixty morphologic and gray-level-based features were extracted from each candidate from both original and VDE CXRs. A nonlinear support vector classifier was employed for classification of the nodule candidates. A publicly available database containing 140 nodules in 140 CXRs and 93 normal CXRs was used for testing our CADe scheme. All nodules were confirmed by computed tomography examinations, and the average size of the nodules was 17.8 mm. Thirty percent (42/140) of the nodules were rated "extremely subtle" or "very subtle" by a radiologist. The original scheme without VDE technology achieved a sensitivity of 78.6% (110/140) with 5 (1165/233) FPs per image. By use of the VDE technology, more nodules overlapping with ribs or clavicles were detected and the sensitivity was improved substantially to 85.0% (119/140) at the same FP rate in a leave-one-out cross-validation test, whereas the FP rate was reduced to 2.5 (583/233) per image at the same sensitivity level as the original CADe scheme obtained (Difference between the specificities of the original and the VDE-based CADe schemes was statistically significant). In particular, the sensitivity of our VDE-based CADe scheme for subtle nodules (66.7% = 28/42) was statistically significantly higher than that of the original CADe scheme (57.1% = 24/42). Therefore, by use of VDE technology, the sensitivity and specificity of our CADe scheme for detection of nodules, especially subtle nodules, in CXRs were improved substantially.

Hierarchical representation of shapes in visual cortex—from localized features to figural shape segregation

PubMed Central

Tschechne, Stephan; Neumann, Heiko

2014-01-01

Visual structures in the environment are segmented into image regions and those combined to a representation of surfaces and prototypical objects. Such a perceptual organization is performed by complex neural mechanisms in the visual cortex of primates. Multiple mutually connected areas in the ventral cortical pathway receive visual input and extract local form features that are subsequently grouped into increasingly complex, more meaningful image elements. Such a distributed network of processing must be capable to make accessible highly articulated changes in shape boundary as well as very subtle curvature changes that contribute to the perception of an object. We propose a recurrent computational network architecture that utilizes hierarchical distributed representations of shape features to encode surface and object boundary over different scales of resolution. Our model makes use of neural mechanisms that model the processing capabilities of early and intermediate stages in visual cortex, namely areas V1–V4 and IT. We suggest that multiple specialized component representations interact by feedforward hierarchical processing that is combined with feedback signals driven by representations generated at higher stages. Based on this, global configurational as well as local information is made available to distinguish changes in the object's contour. Once the outline of a shape has been established, contextual contour configurations are used to assign border ownership directions and thus achieve segregation of figure and ground. The model, thus, proposes how separate mechanisms contribute to distributed hierarchical cortical shape representation and combine with processes of figure-ground segregation. Our model is probed with a selection of stimuli to illustrate processing results at different processing stages. We especially highlight how modulatory feedback connections contribute to the processing of visual input at various stages in the processing hierarchy. PMID:25157228

Object-Oriented Image Clustering Method Using UAS Photogrammetric Imagery

NASA Astrophysics Data System (ADS)

Lin, Y.; Larson, A.; Schultz-Fellenz, E. S.; Sussman, A. J.; Swanson, E.; Coppersmith, R.

2016-12-01

Unmanned Aerial Systems (UAS) have been used widely as an imaging modality to obtain remotely sensed multi-band surface imagery, and are growing in popularity due to their efficiency, ease of use, and affordability. Los Alamos National Laboratory (LANL) has employed the use of UAS for geologic site characterization and change detection studies at a variety of field sites. The deployed UAS equipped with a standard visible band camera to collect imagery datasets. Based on the imagery collected, we use deep sparse algorithmic processing to detect and discriminate subtle topographic features created or impacted by subsurface activities. In this work, we develop an object-oriented remote sensing imagery clustering method for land cover classification. To improve the clustering and segmentation accuracy, instead of using conventional pixel-based clustering methods, we integrate the spatial information from neighboring regions to create super-pixels to avoid salt-and-pepper noise and subsequent over-segmentation. To further improve robustness of our clustering method, we also incorporate a custom digital elevation model (DEM) dataset generated using a structure-from-motion (SfM) algorithm together with the red, green, and blue (RGB) band data for clustering. In particular, we first employ an agglomerative clustering to create an initial segmentation map, from where every object is treated as a single (new) pixel. Based on the new pixels obtained, we generate new features to implement another level of clustering. We employ our clustering method to the RGB+DEM datasets collected at the field site. Through binary clustering and multi-object clustering tests, we verify that our method can accurately separate vegetation from non-vegetation regions, and are also able to differentiate object features on the surface.

Hierarchical representation of shapes in visual cortex-from localized features to figural shape segregation.

PubMed

Tschechne, Stephan; Neumann, Heiko

2014-01-01

Visual structures in the environment are segmented into image regions and those combined to a representation of surfaces and prototypical objects. Such a perceptual organization is performed by complex neural mechanisms in the visual cortex of primates. Multiple mutually connected areas in the ventral cortical pathway receive visual input and extract local form features that are subsequently grouped into increasingly complex, more meaningful image elements. Such a distributed network of processing must be capable to make accessible highly articulated changes in shape boundary as well as very subtle curvature changes that contribute to the perception of an object. We propose a recurrent computational network architecture that utilizes hierarchical distributed representations of shape features to encode surface and object boundary over different scales of resolution. Our model makes use of neural mechanisms that model the processing capabilities of early and intermediate stages in visual cortex, namely areas V1-V4 and IT. We suggest that multiple specialized component representations interact by feedforward hierarchical processing that is combined with feedback signals driven by representations generated at higher stages. Based on this, global configurational as well as local information is made available to distinguish changes in the object's contour. Once the outline of a shape has been established, contextual contour configurations are used to assign border ownership directions and thus achieve segregation of figure and ground. The model, thus, proposes how separate mechanisms contribute to distributed hierarchical cortical shape representation and combine with processes of figure-ground segregation. Our model is probed with a selection of stimuli to illustrate processing results at different processing stages. We especially highlight how modulatory feedback connections contribute to the processing of visual input at various stages in the processing hierarchy.

MRI measurements of Blood-Brain Barrier function in dementia: A review of recent studies.

PubMed

Raja, Rajikha; Rosenberg, Gary A; Caprihan, Arvind

2018-05-15

Blood-brain barrier (BBB) separates the systemic circulation and the brain, regulating transport of most molecules to protect the brain microenvironment. Multiple structural and functional components preserve the integrity of the BBB. Several imaging modalities are available to study disruption of the BBB. However, the subtle changes in BBB leakage that occurs in vascular cognitive impairment and Alzheimer's disease have been less well studied. Dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) is the most widely adopted non-invasive imaging technique for evaluating BBB breakdown. It is used as a significant marker for a wide variety of diseases with large permeability leaks, such as brain tumors and multiple sclerosis, to more subtle disruption in chronic vascular disease and dementia. DCE-MRI analysis of BBB includes both model-free parameters and quantitative parameters using pharmacokinetic modelling. We review MRI studies of BBB breakdown in dementia. The challenges in measuring subtle BBB changes and the state of the art techniques are initially examined. Subsequently, a systematic review comparing methodologies from recent in-vivo MRI studies is presented. Various factors related to subtle BBB permeability measurement such as DCE-MRI acquisition parameters, arterial input assessment, T 1 mapping and data analysis methods are reviewed with the focus on finding the optimal technique. Finally, the reported BBB permeability values in dementia are compared across different studies and across various brain regions. We conclude that reliable measurement of low-level BBB permeability across sites remains a difficult problem and a standardization of the methodology for both data acquisition and quantitative analysis is required. This article is part of the Special Issue entitled 'Cerebral Ischemia'. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of Hurricane Katrina on the fish fauna of the Pascagoula River Drainage

Treesearch

J. Schaefer; P. Mickle; J. Spaeth; B.R. Kreiser; S.B. Adams; W. Matamoros; B. Zuber; P. Vigueira

2006-01-01

Large tropical storms can have dramatic effects on coastal, estuarine and terrestrial ecosystems. However, it is not as well understood how these types of disturbances might impact freshwater communities further inland. Storm surges can change critical water quality parameters for kilometers upstream, potentially causing subtle shifts in community structure or more...

Using Molecular Modeling to Understand Some of the More Subtle Aspects of Aromaticity and Antiaromaticity

ERIC Educational Resources Information Center

Box, Vernon G. S.

2011-01-01

pi-Electron delocalization exerts one of the most significant structure or energy influences in organic chemistry. Apart from determining the shapes of alkenes and alkynes, the planarity of aromatic molecules is a hallmark of pi-electron delocalization. Huckel's rules for aromaticity are easily applied in the teaching of undergraduates, but…

A Genre-Based Investigation of Discussion Sections of Research Articles in Dentistry and Disciplinary Variation

ERIC Educational Resources Information Center

Basturkmen, Helen

2012-01-01

Outwardly the rhetorical organisation of sections of research reports in different disciplines can appear similar. Close examination, however, may reveal subtle differences. Numerous studies have drawn on the genre-based approach developed by Swales (1990, 2004) to investigate the schematic structure of sections of articles in a range of…

Conservation of forest birds: evidence of a shifting baseline in community structure

Treesearch

Chadwick D. Rittenhouse; Anna M. Pidgeon; Thomas P. Albright; Patrick D. Culbert; Murray K. Clayton; Curtis H. Flather; Chengquan Huang; Jeffrey G. Masek; Susan I. Stewart; Volker C. Radeloff

2010-01-01

Quantifying changes in forest bird diversity is an essential task for developing effective conservation actions. When subtle changes in diversity accumulate over time, annual comparisons may offer an incomplete perspective of changes in diversity. In this case, progressive change, the comparison of changes in diversity from a baseline condition, may offer greater...

Subcontinental impacts of an invasive tree disease on forest structure and dynamics

Treesearch

Jeffrey R. Garnas; Matthew P. Ayres; Andrew M. Liebhold; Celia. Evans

2011-01-01

Introduced pests and pathogens are a major source of disturbance to ecosystems world-wide. The famous examples have produced dramatic reductions in host abundance, including virtual extirpation, but most introductions have more subtle impacts that are hard to quantify but are potentially at least as important due to the pathogens' effects on host reproduction,...

Identity Matters: The Centrality of "Conferred Identity" as Symbolic Power and Social Capital in Higher Education Mobility

ERIC Educational Resources Information Center

Holt, Brenda

2012-01-01

Although any "choice" young people make about higher education incorporates a subtle interplay of individual agency, circumstance and social structure, the centrality of identity in such life choices for rural young people cannot be underestimated. Since mobility is an ontological absolute for most rural young people accessing…

Becoming Legible: Helping Students Navigate Promotional Genres of Self-Narration

ERIC Educational Resources Information Center

Vander Zee, Anton

2017-01-01

The five-paragraph essay is a hard genre to love. Its inverted-triangle intro has enlightened us with too many "dawns" of some monolithic "man." It reduces arguments, which tend to be rather subtle creatures, to the confines of a single-sentence thesis. It confects arguments in bland triplicate structure, as if any claim could…

Properties of Self-Assembled Monolayers Revealed via Inverse Tensiometry.

PubMed

Chen, Jiahao; Wang, Zhengjia; Oyola-Reynoso, Stephanie; Thuo, Martin M

2017-11-28

Self-assembled monolayers (SAMs) have emerged as a simple platform technology and hence have been broadly studied. With advances in state-of-the-art fabrication and characterization methods, new insights into SAM structure and related properties have been delineated, albeit with some discrepancies and/or incoherencies. Some discrepancies, especially between experimental and theoretical work, are in part due to the misunderstanding of subtle structural features such as phase evolution and SAM quality. Recent work has, however, shown that simple techniques, such as the measurement of static contact angles, can be used to delineate otherwise complex properties of the SAM, especially when complemented by other more advanced techniques. In this article, we highlight the effect of nanoscale substrate asperities and molecular chain length on the SAM structure and associated properties. First, surfaces with tunable roughness are prepared on both Au and Ag, and their corresponding n-alkanethiolate SAMs are characterized through wetting and spectroscopy. From these data, chain-length- and substrate-morphology-dependent limits to the odd-even effect (structure and properties vary with the number of carbons in the molecules and the nature of the substrate), parametrization of gauche defect densities, and structural phase evolution (liquidlike, waxy, crystalline interfaces) are deduced. An evaluation of the correlation between the effect of roughness and the components of surface tension (polar-γ p and dispersive-γ d ) reveals that wetting, at nanoscale rough surfaces, evolves proportionally with the ratio of the two components of surface tension. The evolution of conformational order is captured over a range of molecular lengths and parametrized through a dimensionless number, χ c . By deploying a well-known tensiometry technique (herein the liquid is used to characterize the solid, hence the term inverse tensiometry) to characterize SAMs, we demonstrate that complex molecular-level phenomena in SAMs can be understood through simplicity.

Structural and Functional Aspects of Class A Carbapenemases

PubMed Central

Naas, Thierry; Dortet, Laurent; Iorga, Bogdan I.

2016-01-01

The fight against infectious diseases is probably one of the greatest public health challenges faced by our society, especially with the emergence of carbapenem-resistant gram-negatives that are in some cases pan-drug resistant. Currently, β-lactamase-mediated resistance does not spare even the newest and most powerful β-lactams (carbapenems), whose activity is challenged by carbapenemases. The worldwide dissemination of carbapenemases in gram-negative organisms threatens to take medicine back into the pre-antibiotic era since the mortality associated with infections caused by these “superbugs” is very high, due to limited treatment options. Clinically-relevant carbapenemases belong either to metallo-β-lactamases (MBLs) of Ambler class B or to serine-β-lactamases (SBLs) of Ambler class A and D enzymes. Class A carbapenemases may be chromosomally-encoded (SME, NmcA, SFC-1, BIC-1, PenA, FPH-1, SHV-38), plasmid-encoded (KPC, GES, FRI-1) or both (IMI). The plasmid-encoded enzymes are often associated with mobile elements responsible for their mobilization. These enzymes, even though weakly related in terms of sequence identities, share structural features and a common mechanism of action. They variably hydrolyse penicillins, cephalosporins, monobactams, carbapenems, and are inhibited by clavulanate and tazobactam. Three-dimensional structures of class A carbapenemases, in the apo form or in complex with substrates/inhibitors, together with site-directed mutagenesis studies, provide essential input for identifying the structural factors and subtle conformational changes that influence the hydrolytic profile and inhibition of these enzymes. Overall, these data represent the building blocks for understanding the structure-function relationships that define the phenotypes of class A carbapenemases and can guide the design of new molecules of therapeutic interest. PMID:26960341

Solution structure of a modified 2′,5′-linked RNA hairpin involved in an equilibrium with duplex

PubMed Central

Plevnik, Miha; Gdaniec, Zofia; Plavec, Janez

2005-01-01

The isomerization of phosphodiester functionality of nucleic acids from 3′,5′- to a less common 2′,5′-linkage influences the complex interplay of stereoelectronic effects that drive pseudorotational equilibrium of sugar rings and thus affect the conformational propensities for compact or more extended structures. The present study highlights the subtle balance of non-covalent forces at play in structural equilibrium of 2′,5′-linked RNA analogue, 3′-O-(2-methoxyethyl) substituted dodecamer *CG*CGAA*U*U*CG*CG, 3′-MOE-2′,5′-RNA, where all cytosines and uracils are methylated at C5. The NMR and UV spectroscopic studies have shown that 3′-MOE-2′,5′-RNA adopts both hairpin and duplex secondary structures, which are involved in a dynamic exchange that is slow on the NMR timescale and exhibits strand and salt concentration as well as pH dependence. Unusual effect of pH over a narrow physiological range is observed for imino proton resonances with exchange broadening observed at lower pH and relatively sharp lines observed at higher pH. The solution structure of 3′-MOE-2′,5′-RNA hairpin displays a unique and well-defined loop, which is stabilized by Watson–Crick A5·*U8 base pair and by n → π* stacking interactions of O4′ lone-pair electrons of A6 and *U8 with aromatic rings of A5 and *U7, respectively. In contrast, the stem region of 3′-MOE-2′,5′-RNA hairpin is more flexible. Our data highlight the important feature of backbone modifications that can have pronounced effects on interstrand association of nucleic acids. PMID:15788747

Neural correlates of processing facial identity based on features versus their spacing.

PubMed

Maurer, D; O'Craven, K M; Le Grand, R; Mondloch, C J; Springer, M V; Lewis, T L; Grady, C L

2007-04-08

Adults' expertise in recognizing facial identity involves encoding subtle differences among faces in the shape of individual facial features (featural processing) and in the spacing among features (a type of configural processing called sensitivity to second-order relations). We used fMRI to investigate the neural mechanisms that differentiate these two types of processing. Participants made same/different judgments about pairs of faces that differed only in the shape of the eyes and mouth, with minimal differences in spacing (featural blocks), or pairs of faces that had identical features but differed in the positions of those features (spacing blocks). From a localizer scan with faces, objects, and houses, we identified regions with comparatively more activity for faces, including the fusiform face area (FFA) in the right fusiform gyrus, other extrastriate regions, and prefrontal cortices. Contrasts between the featural and spacing conditions revealed distributed patterns of activity differentiating the two conditions. A region of the right fusiform gyrus (near but not overlapping the localized FFA) showed greater activity during the spacing task, along with multiple areas of right frontal cortex, whereas left prefrontal activity increased for featural processing. These patterns of activity were not related to differences in performance between the two tasks. The results indicate that the processing of facial features is distinct from the processing of second-order relations in faces, and that these functions are mediated by separate and lateralized networks involving the right fusiform gyrus, although the FFA as defined from a localizer scan is not differentially involved.

Divided spatial attention and feature-mixing errors.

PubMed

Golomb, Julie D

2015-11-01

Spatial attention is thought to play a critical role in feature binding. However, often multiple objects or locations are of interest in our environment, and we need to shift or split attention between them. Recent evidence has demonstrated that shifting and splitting spatial attention results in different types of feature-binding errors. In particular, when two locations are simultaneously sharing attentional resources, subjects are susceptible to feature-mixing errors; that is, they tend to report a color that is a subtle blend of the target color and the color at the other attended location. The present study was designed to test whether these feature-mixing errors are influenced by target-distractor similarity. Subjects were cued to split attention across two different spatial locations, and were subsequently presented with an array of colored stimuli, followed by a postcue indicating which color to report. Target-distractor similarity was manipulated by varying the distance in color space between the two attended stimuli. Probabilistic modeling in all cases revealed shifts in the response distribution consistent with feature-mixing errors; however, the patterns differed considerably across target-distractor color distances. With large differences in color, the findings replicated the mixing result, but with small color differences, repulsion was instead observed, with the reported target color shifted away from the other attended color.

Automatic detection of suspicious behavior of pickpockets with track-based features in a shopping mall

NASA Astrophysics Data System (ADS)

Bouma, Henri; Baan, Jan; Burghouts, Gertjan J.; Eendebak, Pieter T.; van Huis, Jasper R.; Dijk, Judith; van Rest, Jeroen H. C.

2014-10-01

Proactive detection of incidents is required to decrease the cost of security incidents. This paper focusses on the automatic early detection of suspicious behavior of pickpockets with track-based features in a crowded shopping mall. Our method consists of several steps: pedestrian tracking, feature computation and pickpocket recognition. This is challenging because the environment is crowded, people move freely through areas which cannot be covered by a single camera, because the actual snatch is a subtle action, and because collaboration is complex social behavior. We carried out an experiment with more than 20 validated pickpocket incidents. We used a top-down approach to translate expert knowledge in features and rules, and a bottom-up approach to learn discriminating patterns with a classifier. The classifier was used to separate the pickpockets from normal passers-by who are shopping in the mall. We performed a cross validation to train and evaluate our system. In this paper, we describe our method, identify the most valuable features, and analyze the results that were obtained in the experiment. We estimate the quality of these features and the performance of automatic detection of (collaborating) pickpockets. The results show that many of the pickpockets can be detected at a low false alarm rate.

Micrometeoroid Impacts on the Hubble Sace Telescope Wide Field and Planetary Camera 2: Ion Beam Analysis of Subtle Impactor Traces

NASA Technical Reports Server (NTRS)

Grime, G. W.; Webb, R. P.; Jeynes, C.; Palitsin, V. V.; Colaux, J. L.; Kearsley, A. T.; Ross, D. K.; Anz-Meador, P.; Liou, J. C.; Opiela, J.;

Early abnormalities of cardiovascular structure and function in middle-aged Korean adults with prehypertension: The Korean Genome Epidemiology study.

PubMed

Kim, Seong Hwan; Cho, Goo-Yeong; Baik, Inkyung; Lim, Sang Yup; Choi, Cheol Ung; Lim, Hong Euy; Kim, Eung Ju; Park, Chang Gyu; Park, Juri; Kim, Jinyoung; Shin, Chol

2011-02-01

Prehypertension is associated with increased cardiovascular morbidity and mortality. However, there are few population-based studies on the changes of cardiovascular structure and function that characterize prehypertension. The aim of this study was to assess whether prehypertension is associated with abnormalities of cardiovascular structure and function in the general Korean population. We analyzed the cross-sectional relationships between prehypertension and cardiovascular structure and function in a sample from the Korean Genome Epidemiology Study. A total of 1,671 individuals (54.5% women; mean age: 53 ± 6 years) without hypertension and diabetes mellitus were enrolled. Cardiovascular structure and function were assessed by conventional echocardiography, tissue Doppler imaging (TDI), carotid ultrasonography, and pulse wave velocity (PWV). The left ventricular (LV) mass index was significantly higher in subjects with prehypertension than in those with normotension (41 ± 8 g/m²·⁷ vs. 38 ± 7 g/m²·⁷, P < 0.001). LV diastolic parameters, such as the E/A ratio, TDI E(a) velocity, and E/E(a) ratio, were also impaired in subjects with prehypertension (all P < 0.001). Compared with normotension, prehypertension was characterized by a significantly higher common carotid artery intima-media thickness and a higher brachial-ankle PWV (all P < 0.001). These abnormalities of cardiovascular structure and function remained significant after adjustment for covariates. In this population-based cohort, we found that subtle alterations in cardiovascular structure and function were already present at the prehypertensive stage. Whether such subtle alterations convey an increased risk of cardiovascular events and whether the changes are reversible with treatment warrant further study.

Inference of Population Structure using Dense Haplotype Data

PubMed Central

Lawson, Daniel John; Hellenthal, Garrett

2012-01-01

The advent of genome-wide dense variation data provides an opportunity to investigate ancestry in unprecedented detail, but presents new statistical challenges. We propose a novel inference framework that aims to efficiently capture information on population structure provided by patterns of haplotype similarity. Each individual in a sample is considered in turn as a recipient, whose chromosomes are reconstructed using chunks of DNA donated by the other individuals. Results of this “chromosome painting” can be summarized as a “coancestry matrix,” which directly reveals key information about ancestral relationships among individuals. If markers are viewed as independent, we show that this matrix almost completely captures the information used by both standard Principal Components Analysis (PCA) and model-based approaches such as STRUCTURE in a unified manner. Furthermore, when markers are in linkage disequilibrium, the matrix combines information across successive markers to increase the ability to discern fine-scale population structure using PCA. In parallel, we have developed an efficient model-based approach to identify discrete populations using this matrix, which offers advantages over PCA in terms of interpretability and over existing clustering algorithms in terms of speed, number of separable populations, and sensitivity to subtle population structure. We analyse Human Genome Diversity Panel data for 938 individuals and 641,000 markers, and we identify 226 populations reflecting differences on continental, regional, local, and family scales. We present multiple lines of evidence that, while many methods capture similar information among strongly differentiated groups, more subtle population structure in human populations is consistently present at a much finer level than currently available geographic labels and is only captured by the haplotype-based approach. The software used for this article, ChromoPainter and fineSTRUCTURE, is available from http://www.paintmychromosomes.com/. PMID:22291602

Facial Cosmetics Exert a Greater Influence on Processing of the Mouth Relative to the Eyes: Evidence from the N170 Event-Related Potential Component.

PubMed

Tanaka, Hideaki

2016-01-01

Cosmetic makeup significantly influences facial perception. Because faces consist of similar physical structures, cosmetic makeup is typically used to highlight individual features, particularly those of the eyes (i.e., eye shadow) and mouth (i.e., lipstick). Though event-related potentials have been utilized to study various aspects of facial processing, the influence of cosmetics on specific ERP components remains unclear. The present study aimed to investigate the relationship between the application of cosmetic makeup and the amplitudes of the P1 and N170 event-related potential components during facial perception tasks. Moreover, the influence of visual perception on N170 amplitude, was evaluated under three makeup conditions: Eye Shadow, Lipstick, and No Makeup. Electroencephalography was used to monitor 17 participants who were exposed to visual stimuli under each these three makeup conditions. The results of the present study subsequently demonstrated that the Lipstick condition elicited a significantly greater N170 amplitude than the No Makeup condition, while P1 amplitude was unaffected by any of the conditions. Such findings indicate that the application of cosmetic makeup alters general facial perception but exerts no influence on the perception of low-level visual features. Collectively, these results support the notion that the application of makeup induces subtle alterations in the processing of facial stimuli, with a particular effect on the processing of specific facial components (i.e., the mouth), as reflected by changes in N170 amplitude.

Facial Cosmetics Exert a Greater Influence on Processing of the Mouth Relative to the Eyes: Evidence from the N170 Event-Related Potential Component

PubMed Central

Tanaka, Hideaki

2016-01-01

Cosmetic makeup significantly influences facial perception. Because faces consist of similar physical structures, cosmetic makeup is typically used to highlight individual features, particularly those of the eyes (i.e., eye shadow) and mouth (i.e., lipstick). Though event-related potentials have been utilized to study various aspects of facial processing, the influence of cosmetics on specific ERP components remains unclear. The present study aimed to investigate the relationship between the application of cosmetic makeup and the amplitudes of the P1 and N170 event-related potential components during facial perception tasks. Moreover, the influence of visual perception on N170 amplitude, was evaluated under three makeup conditions: Eye Shadow, Lipstick, and No Makeup. Electroencephalography was used to monitor 17 participants who were exposed to visual stimuli under each these three makeup conditions. The results of the present study subsequently demonstrated that the Lipstick condition elicited a significantly greater N170 amplitude than the No Makeup condition, while P1 amplitude was unaffected by any of the conditions. Such findings indicate that the application of cosmetic makeup alters general facial perception but exerts no influence on the perception of low-level visual features. Collectively, these results support the notion that the application of makeup induces subtle alterations in the processing of facial stimuli, with a particular effect on the processing of specific facial components (i.e., the mouth), as reflected by changes in N170 amplitude. PMID:27656161

Inflammatory Myofibroblastic Tumors of the Female Genital Tract Are Under-recognized

PubMed Central

Pickett, Justine L.; Chou, Angela; Andrici, Juliana A.; Clarkson, Adele; Sioson, Loretta; Sheen, Amy; Reagh, Jessica; Najdawi, Fedaa; Kim, Yoomee; Riley, Denise; Maidens, Jayne; Nevell, David; McIlroy, Kirsten; Valmadre, Susan; Gard, Greg; Hogg, Russell; Turchini, John; Robertson, Gregory; Friedlander, Michael

2017-01-01

Inflammatory myofibroblastic tumor (IMT) of the female genital tract is under-recognized. We investigated the prevalence of ALK-positive IMT in lesions previously diagnosed as gynecologic smooth muscle tumors. Immunohistochemistry (IHC) for ALK was performed on tissue microarrays of unselected tumors resected from 2009 to 2013. Three of 1176 (0.26%) “leiomyomas” and 1 of 44 (2.3%) “leiomyosarcomas” were ALK IHC positive, confirmed translocated by fluorescence in situ hybridization (FISH) and therefore more appropriately classified as IMT. On review significant areas of all 4 tumors closely mimicked smooth muscle tumors morphologically, but all showed at least subtle/focal features suggesting IMT. Recognizing that the distinction between IMT and leiomyoma/leiomyosarcoma can be subtle, we then reviewed 1 hematoxylin and eosin slide from each patient undergoing surgery for “leiomyoma” from 2014 to 2017 and selected cases for ALK IHC with a low threshold. Of these, 30 of 571 (5.3%) underwent IHC. Two were confirmed to be IHC positive and FISH rearranged. Of the 6 IMTs, only 1 tumor with a previous diagnosis of leiomyosarcoma, an infiltrative margin and equivocal necrosis, metastasized. Of note it demonstrated a less aggressive clinical course compared with most metastatic leiomyosarcomas (alive with disease at 6 y). The patient was subsequently offered crizotinib to which she responded rapidly. In conclusion, IMTs may closely mimic gynecologic smooth muscle tumors. IMTs account for at least 5 of 1747 (0.3%) tumors previously diagnosed as leiomyoma and 1 of 44 (2.3%) as leiomyosarcoma. These tumors may be recognized prospectively with awareness of subtle/focal histologic clues, coupled with a low threshold for ALK IHC. PMID:28731868

Caring or daring? Exploring the impact of facial masculinity/femininity and gender category information on first impressions.

PubMed

Walker, Mirella; Wänke, Michaela

2017-01-01

In two studies we disentangled and systematically investigated the impact of subtle facial cues to masculinity/femininity and gender category information on first impressions. Participants judged the same unambiguously male and female target persons-either with masculine or feminine facial features slightly enhanced-regarding stereotypically masculine (i.e., competence) and feminine (i.e., warmth) personality traits. Results of both studies showed a strong effect of facial masculinity/femininity: Masculine-looking persons were seen as colder and more competent than feminine-looking persons. This effect of facial masculinity/femininity was not only found for typical (i.e., masculine-looking men and feminine-looking women) and atypical (i.e., masculine-looking women and feminine-looking men) category members; it was even found to be more pronounced for atypical than for typical category members. This finding reveals that comparing atypical members to the group prototype results in pronounced effects of facial masculinity/femininity. These contrast effects for atypical members predominate assimilation effects for typical members. Intriguingly, very subtle facial cues to masculinity/femininity strongly guide first impressions and may have more impact than the gender category.

Caring or daring? Exploring the impact of facial masculinity/femininity and gender category information on first impressions

PubMed Central

Walker, Mirella; Wänke, Michaela

2017-01-01

In two studies we disentangled and systematically investigated the impact of subtle facial cues to masculinity/femininity and gender category information on first impressions. Participants judged the same unambiguously male and female target persons–either with masculine or feminine facial features slightly enhanced–regarding stereotypically masculine (i.e., competence) and feminine (i.e., warmth) personality traits. Results of both studies showed a strong effect of facial masculinity/femininity: Masculine-looking persons were seen as colder and more competent than feminine-looking persons. This effect of facial masculinity/femininity was not only found for typical (i.e., masculine-looking men and feminine-looking women) and atypical (i.e., masculine-looking women and feminine-looking men) category members; it was even found to be more pronounced for atypical than for typical category members. This finding reveals that comparing atypical members to the group prototype results in pronounced effects of facial masculinity/femininity. These contrast effects for atypical members predominate assimilation effects for typical members. Intriguingly, very subtle facial cues to masculinity/femininity strongly guide first impressions and may have more impact than the gender category. PMID:29023451

Discrimination of acoustic communication signals by grasshoppers (Chorthippus biguttulus): temporal resolution, temporal integration, and the impact of intrinsic noise.

PubMed

Ronacher, Bernhard; Wohlgemuth, Sandra; Vogel, Astrid; Krahe, Rüdiger

2008-08-01

A characteristic feature of hearing systems is their ability to resolve both fast and subtle amplitude modulations of acoustic signals. This applies also to grasshoppers, which for mate identification rely mainly on the characteristic temporal patterns of their communication signals. Usually the signals arriving at a receiver are contaminated by various kinds of noise. In addition to extrinsic noise, intrinsic noise caused by stochastic processes within the nervous system contributes to making signal recognition a difficult task. The authors asked to what degree intrinsic noise affects temporal resolution and, particularly, the discrimination of similar acoustic signals. This study aims at exploring the neuronal basis for sexual selection, which depends on exploiting subtle differences between basically similar signals. Applying a metric, by which the similarities of spike trains can be assessed, the authors investigated how well the communication signals of different individuals of the same species could be discriminated and correctly classified based on the responses of auditory neurons. This spike train metric yields clues to the optimal temporal resolution with which spike trains should be evaluated. (c) 2008 APA, all rights reserved

2.5D change detection from satellite imagery to monitor small-scale mining activities in the Democratic Republic of the Congo

NASA Astrophysics Data System (ADS)

Kranz, Olaf; Lang, Stefan; Schoepfer, Elisabeth

2017-09-01

Mining natural resources serve fundamental societal needs or commercial interests, but it may well turn into a driver of violence and regional instability. In this study, very high resolution (VHR) optical stereo satellite data are analysed to monitor processes and changes in one of the largest artisanal and small-scale mining sites in the Democratic Republic of the Congo, which is among the world's wealthiest countries in exploitable minerals To identify the subtle structural changes, the applied methodological framework employs object-based change detection (OBCD) based on optical VHR data and generated digital surface models (DSM). Results prove the DSM-based change detection approach enhances the assessment gained from sole 2D analyses by providing valuable information about changes in surface structure or volume. Land cover changes as analysed by OBCD reveal an increase in bare soil area by a rate of 47% between April 2010 and September 2010, followed by a significant decrease of 47.5% until March 2015. Beyond that, DSM differencing enabled the characterisation of small-scale features such as pits and excavations. The presented Earth observation (EO)-based monitoring of mineral exploitation aims at a better understanding of the relations between resource extraction and conflict, and thus providing relevant information for potential mitigation strategies and peace building.

Closed-loop ARS mode for scanning ion conductance microscopy with improved speed and stability for live cell imaging applications.

PubMed

Jung, Goo-Eun; Noh, Hanaul; Shin, Yong Kyun; Kahng, Se-Jong; Baik, Ku Youn; Kim, Hong-Bae; Cho, Nam-Joon; Cho, Sang-Joon

2015-07-07

Scanning ion conductance microscopy (SICM) is an increasingly useful nanotechnology tool for non-contact, high resolution imaging of live biological specimens such as cellular membranes. In particular, approach-retract-scanning (ARS) mode enables fast probing of delicate biological structures by rapid and repeated approach/retraction of a nano-pipette tip. For optimal performance, accurate control of the tip position is a critical issue. Herein, we present a novel closed-loop control strategy for the ARS mode that achieves higher operating speeds with increased stability. The algorithm differs from that of most conventional (i.e., constant velocity) approach schemes as it includes a deceleration phase near the sample surface, which is intended to minimize the possibility of contact with the surface. Analysis of the ion current and tip position demonstrates that the new mode is able to operate at approach speeds of up to 250 μm s(-1). As a result of the improved stability, SICM imaging with the new approach scheme enables significantly improved, high resolution imaging of subtle features of fixed and live cells (e.g., filamentous structures & membrane edges). Taken together, the results suggest that optimization of the tip approach speed can substantially improve SICM imaging performance, further enabling SICM to become widely adopted as a general and versatile research tool for biological studies at the nanoscale level.

Binding of Capsaicin to the TRPV1 Ion Channel.

PubMed

Darré, Leonardo; Domene, Carmen

2015-12-07

Transient receptor potential (TRP) ion channels constitute a notable family of cation channels involved in the ability of an organisms to detect noxious mechanical, thermal, and chemical stimuli that give rise to the perception of pain, taste, and changes in temperature. One of the most experimentally studied agonist of TRP channels is capsaicin, which is responsible for the burning sensation produced when chili pepper is in contact with organic tissues. Thus, understanding how this molecule interacts and regulates TRP channels is essential to high impact pharmacological applications, particularly those related to pain treatment. The recent publication of a three-dimensional structure of the vanilloid receptor 1 (TRPV1) in the absence and presence of capsaicin from single particle electron cryomicroscopy experiments provides the opportunity to explore these questions at the atomic level. In the present work, molecular docking and unbiased and biased molecular dynamics simulations were employed to generate a structural model of the capsaicin-channel complex. In addition, the standard free energy of binding was estimated using alchemical transformations coupled with conformational, translational, and orientational restraints on the ligand. Key binding modes consistent with previous experimental data are identified, and subtle but essential dynamical features of the binding site are characterized. These observations shed some light into how TRPV1 interacts with capsaicin, and may help to refine design parameters for new TRPV1 antagonists, and potentially guide further developments of TRP channel modulators.

Molecular evolution of miraculin-like proteins in soybean Kunitz super-family.

PubMed

Selvakumar, Purushotham; Gahloth, Deepankar; Tomar, Prabhat Pratap Singh; Sharma, Nidhi; Sharma, Ashwani Kumar

2011-12-01

Miraculin-like proteins (MLPs) belong to soybean Kunitz super-family and have been characterized from many plant families like Rutaceae, Solanaceae, Rubiaceae, etc. Many of them possess trypsin inhibitory activity and are involved in plant defense. MLPs exhibit significant sequence identity (~30-95%) to native miraculin protein, also belonging to Kunitz super-family compared with a typical Kunitz family member (~30%). The sequence and structure-function comparison of MLPs with that of a classical Kunitz inhibitor have demonstrated that MLPs have evolved to form a distinct group within Kunitz super-family. Sequence analysis of new genes along with available MLP sequences in the literature revealed three major groups for these proteins. A significant feature of Rutaceae MLP type 2 sequences is the presence of phosphorylation motif. Subtle changes are seen in putative reactive loop residues among different MLPs suggesting altered specificities to specific proteases. In phylogenetic analysis, Rutaceae MLP type 1 and type 2 proteins clustered together on separate branches, whereas native miraculin along with other MLPs formed distinct clusters. Site-specific positive Darwinian selection was observed at many sites in both the groups of Rutaceae MLP sequences with most of the residues undergoing positive selection located in loop regions. The results demonstrate the sequence and thereby the structure-function divergence of MLPs as a distinct group within soybean Kunitz super-family due to biotic and abiotic stresses of local environment.

Surface-enhanced Raman scattering (SERS) study of anthocyanidins

NASA Astrophysics Data System (ADS)

Zaffino, Chiara; Russo, Bianca; Bruni, Silvia

2015-10-01

Anthocyanins are an important class of natural compounds responsible for the red, purple and blue colors in a large number of flowers, fruits and cereal grains. They are polyhydroxy- and polymethoxy-derivatives of 2-phenylbenzopyrylium (flavylium) salts, which are present in nature as glycosylated molecules. The aim of the present study is to assess the identification of anthocyanidins, i.e. anthocyanins without the glycosidic moiety, by means of surface-enhanced Raman spectroscopy (SERS), a very chemically-specific technique which is moreover sensitive to subtle changes in molecular structures. These features can lead to elect SERS, among the spectroscopic tools currently at disposal of scientists, as a technique of choice for the identification of anthocyanidins, since: (1) anthocyanidins structurally present the same benzopyrylium moiety and differentiate only for the substitution pattern on their phenyl ring, (2) different species are present in aqueous solution depending on the pH. It will be demonstrated that, while resonance Raman spectra of anthocyanidins are very similar to one another, SER spectra show greater differences, leading to a further step in the identification of such important compounds in diluted solutions by means of vibrational spectroscopy. Moreover, the dependence on the pH of the six most common anthocyanidins, i.e. cyanidin, delphinidin, pelargonidin, peonidin, malvidin and petunidin, is studied. To the best of the authors' knowledge, a complete SERS study of such important molecules is reported in the present work for the first time.

Lidar-enhanced geologic mapping, examples from the Medford and Hood River areas, Oregon

NASA Astrophysics Data System (ADS)

Wiley, T. J.; McClaughry, J. D.

2012-12-01

Lidar-based 3-foot digital elevation models (DEMs) and derivatives (slopeshade, hillshade, contours) were used to help map geology across 1700 km2 (650 mi2) near Hood River and Medford, Oregon. Techniques classically applied to interpret coarse DEMs and small-scale topographic maps were adapted to take advantage of lidar's high resolution. Penetration and discrimination of plant cover by the laser system allowed recognition of fine patterns and textures related to underlying geologic units and associated soils. Surficial geologic maps were improved by the ability to examine tiny variations in elevation and slope. Recognition of low-relief features of all sizes was enhanced where pixel elevation ranges of centimeters to meters, established by knowledge of the site or by trial, were displayed using thousands of sequential colors. Features can also be depicted relative to stream level by preparing a DEM that compensates for gradient. Near Medford, lidar-derived contour maps with 1- to 3-foot intervals revealed incised bajada with young, distal lobes defined by concentric contour lines. Bedrock geologic maps were improved by recognizing geologic features associated with surface textures and patterns or topographic anomalies. In sedimentary and volcanic terrain, structure was revealed by outcrops or horizons lying at one stratigraphic level. Creating a triangulated irregular network (TIN) facet from positions of three or more such points gives strike and dip. Each map area benefited from hundreds of these measurements. A more extensive DEM in the plane of the TIN facet can be subtracted from surface elevation (lidar DEM) to make a DEM with elevation zero where the stratigraphic horizon lies at the surface. The distribution of higher and lower stratigraphic horizons can be shown by highlighting areas similarly higher or lower on the same DEM. Poor fit of contacts or faults projected between field traverses suggest the nature and amount of intervening geologic structure. Intrusive bodies were locally delimited by linear mounds where contact metamorphism hardened soft, fractured country rock. Bedrock faults were revealed where fault traces formed topographic anomalies or where topography associated with stratigraphic horizons or bedding-parallel textural fabrics was offset. This was important for identification of young faults and associated earthquake hazards. Previously unknown Holocene faults southwest of Hood River appear as subtle lineaments redirecting modern drainages or offsetting glacial moraines or glaciated bedrock. West of Medford, the presence young faulting was confirmed by elevation data that showed bedrock in the channel of the Rogue River at higher elevations below Gold Ray dam than in boreholes upstream. Such obscure structural features would have gone unrecognized using traditional topographic analysis or field reconnaissance. Fieldwork verified that lidar techniques improved our early geologic models, resolution of geologic features, and mapping of surficial and bedrock geology between traverses.

Imaging Lysosomal pH Alteration in Stressed Cells with a Sensitive Ratiometric Fluorescence Sensor.

PubMed

Xue, Zhongwei; Zhao, Hu; Liu, Jian; Han, Jiahuai; Han, Shoufa

2017-03-24

The organelle-specific pH is crucial for cell homeostasis. Aberrant pH of lysosomes has been manifested in myriad diseases. To probe lysosome responses to cell stress, we herein report the detection of lysosomal pH changes with a dual colored probe (CM-ROX), featuring a coumarin domain with "always-on" blue fluorescence and a rhodamine-lactam domain activatable to lysosomal acidity to give red fluorescence. With sensitive ratiometric signals upon subtle pH changes, CM-ROX enables discernment of lysosomal pH changes in cells undergoing autophagy, cell death, and viral infection.

Hyperthyroidism. Causes, clinical features, and diagnosis.

PubMed

Spaulding, S W; Lippes, H

1985-09-01

The usual patient with hyperthyroidism has Graves' disease: If serum levels of thyroid hormone are clearly elevated, the presence of infiltrative ophthalmopathy or pretibial myxedema is probably sufficient for establishing the diagnosis. However, if the ancillary findings of Graves' are not present, the radioactive iodine uptake should be determined to rule out other possible etiologies of hyperthyroidism. Signs of hyperthyroidism may be subtle or misleading, particularly in the elderly; the well-informed clinician keeps the diagnosis in mind, and if the initial thyroid hormone tests are not definitive, employs additional tests that are cost-effective in the individual clinical situation.

Orbital chondroma rodens in a dog.

PubMed

Pletcher, J M; Koch, S A; Stedham, M A

1979-07-15

A chondroma rodens involving the superficial medial aspect of the right orbit was diagnosed in a 9-year-old dog referred because of chronic unilateral epiphora. Examination revealed several ophthalmic abnormalities attributable to a space-occupying mass in the superficial medial aspect of the orbit. The mass was excised; however, regrowths at the primary site necessitated additional surgical interventions. The dog was given radiation therapy, which provided encouraging results. Subtle histologic differences as well as differing epidemiologic features suggest that chondroma rodens is not analogous to the human entity of juvenile aponeurotic fibroma, to which it has been compared in the past.

Fgfr3 regulates development of the caudal telencephalon.

PubMed

Moldrich, Randal X; Mezzera, Cecilia; Holmes, William M; Goda, Sailaja; Brookfield, Sam J; Rankin, Alastair J; Barr, Emily; Kurniawan, Nyoman; Dewar, Deborah; Richards, Linda J; López-Bendito, Guillermina; Iwata, Tomoko

2011-06-01

The fibroblast growth factor receptor 3 (Fgfr3) is expressed in a rostral(low) to caudal(high) gradient in the developing cerebral cortex. Therefore, we hypothesized that Fgfr3 contributes to the correct morphology and connectivity of the caudal cortex. Overall, the forebrain structures appeared normal in Fgfr3(-/-) mice. However, cortical and hippocampal volumes were reduced by 26.7% and 16.3%, respectively. Hypoplasia was particularly evident in the caudo-ventral region of the telencephalon where proliferation was mildly decreased at embryonic day 18.5. Dysplasia of GABAergic neurons in the amygdala and piriform cortex was seen following GAD67 immunohistochemistry. Dye-tracing studies and diffusion magnetic resonance imaging and tractography detected a subtle thalamocortical tract deficit, and significant decreases in the stria terminalis and lateral arms of the anterior commissure. These results indicate the subtle role of Fgfr3 in formation of caudal regions of the telencephalon affecting some brain projections. Copyright © 2011 Wiley-Liss, Inc.

Motion magnification for endoscopic surgery

NASA Astrophysics Data System (ADS)

McLeod, A. Jonathan; Baxter, John S. H.; de Ribaupierre, Sandrine; Peters, Terry M.

2014-03-01

Endoscopic and laparoscopic surgeries are used for many minimally invasive procedures but limit the visual and haptic feedback available to the surgeon. This can make vessel sparing procedures particularly challenging to perform. Previous approaches have focused on hardware intensive intraoperative imaging or augmented reality systems that are difficult to integrate into the operating room. This paper presents a simple approach in which motion is visually enhanced in the endoscopic video to reveal pulsating arteries. This is accomplished by amplifying subtle, periodic changes in intensity coinciding with the patient's pulse. This method is then applied to two procedures to illustrate its potential. The first, endoscopic third ventriculostomy, is a neurosurgical procedure where the floor of the third ventricle must be fenestrated without injury to the basilar artery. The second, nerve-sparing robotic prostatectomy, involves removing the prostate while limiting damage to the neurovascular bundles. In both procedures, motion magnification can enhance subtle pulsation in these structures to aid in identifying and avoiding them.

Physiology modulates social flexibility and collective behaviour in equids and other large ungulates.

PubMed

Gersick, Andrew S; Rubenstein, Daniel I

2017-08-19

Though morphologically very similar, equids across the extant species occupy ecological niches that are surprisingly non-overlapping. Occupancy of these distinct niches appears related to subtle physiological and behavioural adaptations which, in turn, correspond to significant differences in the social behaviours and emergent social systems characterizing the different species. Although instances of intraspecific behavioural variation in equids demonstrate that the same body plan can support a range of social structures, each of these morphologically similar species generally shows robust fidelity to its evolved social system. The pattern suggests a subtle relationship between physiological phenotypes and behavioural flexibility. While environmental conditions can vary widely within relatively short temporal or spatial scales, physiological changes and changes to the behaviours that regulate physiological processes, are constrained to longer cycles of adaptation. Physiology is then the limiting variable in the interaction between ecological variation and behavioural and socio-structural flexibility. Behavioural and socio-structural flexibility, in turn, will generate important feedbacks that will govern physiological function, thus creating a coupled web of interactions that can lead to changes in individual and collective behaviour. Longitudinal studies of equid and other large-bodied ungulate populations under environmental stress, such as those discussed here, may offer the best opportunities for researchers to examine, in real time, the interplay between individual behavioural plasticity, socio-structural flexibility, and the physiological and genetic changes that together produce adaptive change.This article is part of the themed issue 'Physiological determinants of social behaviour in animals'. © 2017 The Author(s).

Four Year-Olds Use Norm-Based Coding for Face Identity

ERIC Educational Resources Information Center

Jeffery, Linda; Read, Ainsley; Rhodes, Gillian

2013-01-01

Norm-based coding, in which faces are coded as deviations from an average face, is an efficient way of coding visual patterns that share a common structure and must be distinguished by subtle variations that define individuals. Adults and school-aged children use norm-based coding for face identity but it is not yet known if pre-school aged…

Social Function and Communication in Optimal Outcome Children and Adolescents with an Autism History on Structured Test Measures

ERIC Educational Resources Information Center

Orinstein, Alyssa J.; Suh, Joyce; Porter, Kaitlyn; De Yoe, Kaitlin A.; Tyson, Katherine E.; Troyb, Eva; Barton, Marianne L.; Eigsti, Inge-Marie; Stevens, Michael C.; Fein, Deborah A.

2015-01-01

Youth who lose their ASD diagnosis may have subtle social and communication difficulties. We examined social and communication functioning in 44 high-functioning autism (HFA), 34 optimal outcome (OO) and 34 typically developing (TD) youth. Results indicated that OO participants had no autism communication symptoms, no pragmatic language deficits,…

Dlx5 Homeodomain: DNA Complex: Structure, Binding and Effect of Mutations Related to Split Hand and Foot Malformation Syndrome

DOE Office of Scientific and Technical Information (OSTI.GOV)

Proudfoot, Andrew; Axelrod, Herbert L.; Geralt, Michael

The Dlx5 homeodomain is a transcription factor related to the Drosophila Distal-less gene that is associated with breast and lung cancer, lymphoma, Rett syndrome and osteoporosis in humans. Mutations in the DLX5 gene have been linked to deficiencies in craniofacial and limb development in higher eukaryotes, including Split Hand and Foot Malformation-1 (SHFM-1) in humans. Our characterization of a Dlx5 homeodomain–(CGACTAATTAGTCG) 2 complex by NMR spectroscopy paved the way for determination of its crystal structure at 1.85 Å resolution that enabled rationalization of the effects of disease-related mutations on the protein function. A remarkably subtle mutation, Q186H, is linked tomore » SHFM-1; this change likely affects affinity of DNA binding by disrupting water-mediated interactions with the DNA major groove. A more subtle effect is implicated for the Q178P mutation, which is not in direct contact with the DNA. Our data indicate that these mutations diminish the ability of the Dlx5 homeodomain to recognize and bind target DNAs, and likely destabilize the formation of functional complexes.« less

Dlx5 Homeodomain: DNA Complex: Structure, Binding and Effect of Mutations Related to Split Hand and Foot Malformation Syndrome

DOE PAGES

Proudfoot, Andrew; Axelrod, Herbert L.; Geralt, Michael; ...

2016-01-29

The Dlx5 homeodomain is a transcription factor related to the Drosophila Distal-less gene that is associated with breast and lung cancer, lymphoma, Rett syndrome and osteoporosis in humans. Mutations in the DLX5 gene have been linked to deficiencies in craniofacial and limb development in higher eukaryotes, including Split Hand and Foot Malformation-1 (SHFM-1) in humans. Our characterization of a Dlx5 homeodomain–(CGACTAATTAGTCG) 2 complex by NMR spectroscopy paved the way for determination of its crystal structure at 1.85 Å resolution that enabled rationalization of the effects of disease-related mutations on the protein function. A remarkably subtle mutation, Q186H, is linked tomore » SHFM-1; this change likely affects affinity of DNA binding by disrupting water-mediated interactions with the DNA major groove. A more subtle effect is implicated for the Q178P mutation, which is not in direct contact with the DNA. Our data indicate that these mutations diminish the ability of the Dlx5 homeodomain to recognize and bind target DNAs, and likely destabilize the formation of functional complexes.« less

MCD spectroscopy of hexanuclear Mn(III) salicylaldoxime single-molecule magnets.

PubMed

Bradley, Justin M; Thomson, Andrew J; Inglis, Ross; Milios, Constantinos J; Brechin, Euan K; Piligkos, Stergios

2010-11-07

The hexanuclear cages [Mn(6)O(2)(R-sao)(6)L(2)(EtOH)(x)(H(2)O)(y)] "Mn(6)" behave as single-molecule magnets (SMMs) below a characteristic blocking temperature. As with [Mn(12)O(12)(O(2)CR)(16)(H(2)O)(4)] "Mn(12)" the electronic absorption spectra are rather featureless, yielding little information on the electronic structure of the magnetic ions. Low temperature Magnetic Circular Dichroism (MCD) spectra afford greater resolution of the optical transitions and also probe the magnetic properties of the system. Both the ground state spin and blocking temperature of the Mn(6) cages are determined by subtle structural perturbations of a generic Mn(6)O(2) core. Absorbance and MCD spectra are reported for [Mn(6)O(2)(Et-sao)(6){O(2)CPh(Me)(2)}(2)(EtOH)(6)] (1), [Mn(6)O(2)(Et-sao)(6){O(2)CPh}(2)(EtOH)(4)(H(2)O)(2)] (2), [Mn(6)O(2)(sao)(6){O(2)CPh}(2)(EtOH)(4)]·EtOH (3) and the trinuclear precursor [Mn(3)O(Et-sao)(3)(MeOH)(3)](ClO(4)) (4) cast into polymer film. SMM behaviour has previously been observed using magnetic susceptibility measurements on powder and single-crystal samples. The ligand field environment of the magnetic ions is assumed to be similar in (1) and (2) and their different blocking temperatures are attributed to the magnitude of the effective exchange constant. The MCD spectra of (1) and (2), in which the ground state spin S = 12, show that the ligand field environments of the Mn ions are almost identical and that magnetic hysteresis persists for isolated molecules when crystal packing forces are removed. The subtle structural differences between (1) and (2) are manifested in the field dependence of the MCD response at different wavelengths that reflect changes in band polarisation. The MCD spectrum of (3) contains features not apparent in those of (1) and (2). These are attributed to 5-coordinate Mn(iii), which is unique to (3) among the compounds studied. (3) has ground state spin S = 4, a lower blocking temperature and consequently no observable hysteresis in the MCD down to 1.7 K. Comparison of the MCD spectra of (1)-(3) to that of (4) confirms the integrity of the Mn(6)O(2) core when these materials are cast into polymer film.

Gently does it: Humans outperform a software classifier in recognizing subtle, nonstereotypical facial expressions.

PubMed

Yitzhak, Neta; Giladi, Nir; Gurevich, Tanya; Messinger, Daniel S; Prince, Emily B; Martin, Katherine; Aviezer, Hillel

2017-12-01

According to dominant theories of affect, humans innately and universally express a set of emotions using specific configurations of prototypical facial activity. Accordingly, thousands of studies have tested emotion recognition using sets of highly intense and stereotypical facial expressions, yet their incidence in real life is virtually unknown. In fact, a commonplace experience is that emotions are expressed in subtle and nonprototypical forms. Such facial expressions are at the focus of the current study. In Experiment 1, we present the development and validation of a novel stimulus set consisting of dynamic and subtle emotional facial displays conveyed without constraining expressers to using prototypical configurations. Although these subtle expressions were more challenging to recognize than prototypical dynamic expressions, they were still well recognized by human raters, and perhaps most importantly, they were rated as more ecological and naturalistic than the prototypical expressions. In Experiment 2, we examined the characteristics of subtle versus prototypical expressions by subjecting them to a software classifier, which used prototypical basic emotion criteria. Although the software was highly successful at classifying prototypical expressions, it performed very poorly at classifying the subtle expressions. Further validation was obtained from human expert face coders: Subtle stimuli did not contain many of the key facial movements present in prototypical expressions. Together, these findings suggest that emotions may be successfully conveyed to human viewers using subtle nonprototypical expressions. Although classic prototypical facial expressions are well recognized, they appear less naturalistic and may not capture the richness of everyday emotional communication. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Aversive Disablism: Subtle Prejudice toward Disabled People

ERIC Educational Resources Information Center

Deal, Mark

2007-01-01

Blatant forms of prejudice towards disabled people appear to be disappearing in the UK. However, subtle forms of prejudice remain and may be highly damaging to the achievement of the vision of disabled people being "respected and included as equal members of society". In order to assist placing subtle forms of prejudice within a…

Subtle Alterations in Brain Anatomy May Change an Individual’s Personality in Chronic Pain

PubMed Central

Gustin, Sylvia M.; McKay, Jamie G.; Petersen, Esben T.; Peck, Chris C.; Murray, Greg M.; Henderson, Luke A.

2014-01-01

It is well established that gross prefrontal cortex damage can affect an individual’s personality. It is also possible that subtle prefrontal cortex changes associated with conditions such as chronic pain, and not detectable until recent advances in human brain imaging, may also result in subtle changes in an individual’s personality. In an animal model of chronic neuropathic pain, subtle prefrontal cortex changes including altered basal dendritic length, resulted in altered decision making ability. Using multiple magnetic resonance imaging techniques, we found in humans, although gray matter volume and on-going activity were unaltered, chronic neuropathic pain was associated with reduced free and bound proton movement, indicators of subtle anatomical changes, in the medial prefrontal cortex, anterior cingulate cortex and mediodorsal thalamus. Furthermore, proton spectroscopy revealed an increase in neural integrity in the medial prefrontal cortex in neuropathic pain patients, the degree of which was significantly correlated to the personality temperament of novelty seeking. These data reveal that even subtle changes in prefrontal cortex anatomy may result in a significant change in an individual’s personality. PMID:25291361

Probing Structural Changes among Analogous Inhibitor-Bound Forms of HIV-1 Protease and a Drug-Resistant Mutant in Solution by Nuclear Magnetic Resonance.

PubMed

Khan, Shahid N; Persons, John D; Paulsen, Janet L; Guerrero, Michel; Schiffer, Celia A; Kurt-Yilmaz, Nese; Ishima, Rieko

2018-03-13

In the era of state-of-the-art inhibitor design and high-resolution structural studies, detection of significant but small protein structural differences in the inhibitor-bound forms is critical to further developing the inhibitor. Here, we probed differences in HIV-1 protease (PR) conformation among darunavir and four analogous inhibitor-bound forms and compared them with a drug-resistant mutant using nuclear magnetic resonance chemical shifts. Changes in amide chemical shifts of wild-type (WT) PR among these inhibitor-bound forms, ΔCSP, were subtle but detectable and extended >10 Å from the inhibitor-binding site, asymmetrically between the two subunits of PR. Molecular dynamics simulations revealed differential local hydrogen bonding as the molecular basis of this remote asymmetric change. Inhibitor-bound forms of the drug-resistant mutant also showed a similar long-range ΔCSP pattern. Differences in ΔCSP values of the WT and the mutant (ΔΔCSPs) were observed at the inhibitor-binding site and in the surrounding region. Comparing chemical shift changes among highly analogous inhibitors and ΔΔCSPs effectively eliminated local environmental effects stemming from different chemical groups and enabled exploitation of these sensitive parameters to detect subtle protein conformational changes and to elucidate asymmetric and remote conformational effects upon inhibitor interaction.

The subtle role of climate change on population genetic structure in Canada lynx.

PubMed

Row, Jeffrey R; Wilson, Paul J; Gomez, Celine; Koen, Erin L; Bowman, Jeff; Thornton, Daniel; Murray, Dennis L

2014-07-01

Anthropogenically driven climatic change is expected to reshape global patterns of species distribution and abundance. Given recent links between genetic variation and environmental patterns, climate change may similarly impact genetic population structure, but we lack information on the spatial and mechanistic underpinnings of genetic-climate associations. Here, we show that current genetic variability of Canada lynx (Lynx canadensis) is strongly correlated with a winter climate gradient (i.e. increasing snow depth and winter precipitation from west-to-east) across the Pacific-North American (PNO) to North Atlantic Oscillation (NAO) climatic systems. This relationship was stronger than isolation by distance and not explained by landscape variables or changes in abundance. Thus, these patterns suggest that individuals restricted dispersal across the climate boundary, likely in the absence of changes in habitat quality. We propose habitat imprinting on snow conditions as one possible explanation for this unusual phenomenon. Coupling historical climate data with future projections, we also found increasingly diverging snow conditions between the two climate systems. Based on genetic simulations using projected climate data (2041-2070), we predicted that this divergence could lead to a threefold increase in genetic differentiation, potentially leading to isolated east-west populations of lynx in North America. Our results imply that subtle genetic structure can be governed by current climate and that substantive genetic differentiation and related ecological divergence may arise from changing climate patterns. © 2014 John Wiley & Sons Ltd.

Automatically measuring brain ventricular volume within PACS using artificial intelligence.

PubMed

Yepes-Calderon, Fernando; Nelson, Marvin D; McComb, J Gordon

2018-01-01

The picture archiving and communications system (PACS) is currently the standard platform to manage medical images but lacks analytical capabilities. Staying within PACS, the authors have developed an automatic method to retrieve the medical data and access it at a voxel level, decrypted and uncompressed that allows analytical capabilities while not perturbing the system's daily operation. Additionally, the strategy is secure and vendor independent. Cerebral ventricular volume is important for the diagnosis and treatment of many neurological disorders. A significant change in ventricular volume is readily recognized, but subtle changes, especially over longer periods of time, may be difficult to discern. Clinical imaging protocols and parameters are often varied making it difficult to use a general solution with standard segmentation techniques. Presented is a segmentation strategy based on an algorithm that uses four features extracted from the medical images to create a statistical estimator capable of determining ventricular volume. When compared with manual segmentations, the correlation was 94% and holds promise for even better accuracy by incorporating the unlimited data available. The volume of any segmentable structure can be accurately determined utilizing the machine learning strategy presented and runs fully automatically within the PACS.

X-ray characterization techniques for the assessment of surface damage in crystalline wafers: A model study in AlN

NASA Astrophysics Data System (ADS)

Bobea, M.; Tweedie, J.; Bryan, I.; Bryan, Z.; Rice, A.; Dalmau, R.; Xie, J.; Collazo, R.; Sitar, Z.

2013-03-01

A high-resolution X-ray diffraction method with enhanced surface sensitivity has been used to investigate the effects of various polishing steps on the near-surface region of single crystal substrates. The method involves the study of a highly asymmetric reflection, observable under grazing incidence conditions. Analysis of rocking curve measurements and reciprocal space maps (RSMs) revealed subtle structural differences between the polished substrates. For aluminum nitride wafers, damage induced from diamond sawing and mechanical polishing was readily identifiable by on-axis rocking curves, but this method was unable to distinguish between sample surfaces subjected to various degrees of chemical mechanical polishing (CMP). To characterize sufficiently these surfaces, (10.3) RSMs were measured to provide both qualitative and quantitative information about the near-surface region. Two features present in the RSMs were utilized to quantitatively assess the polished wafers: the magnitude of the diffuse scatter in the omega-scans and the elongation of the crystal truncation rod. The method is able to distinguish between different degrees of CMP surface preparation and provides metrics to quantify subsurface damage after this polishing step.

Abnormal Neural Activation to Faces in the Parents of Children with Autism

PubMed Central

Yucel, G. H.; Belger, A.; Bizzell, J.; Parlier, M.; Adolphs, R.; Piven, J.

2015-01-01

Parents of children with an autism spectrum disorder (ASD) show subtle deficits in aspects of social behavior and face processing, which resemble those seen in ASD, referred to as the “Broad Autism Phenotype ” (BAP). While abnormal activation in ASD has been reported in several brain structures linked to social cognition, little is known regarding patterns in the BAP. We compared autism parents with control parents with no family history of ASD using 2 well-validated face-processing tasks. Results indicated increased activation in the autism parents to faces in the amygdala (AMY) and the fusiform gyrus (FG), 2 core face-processing regions. Exploratory analyses revealed hyper-activation of lateral occipital cortex (LOC) bilaterally in autism parents with aloof personality (“BAP+”). Findings suggest that abnormalities of the AMY and FG are related to underlying genetic liability for ASD, whereas abnormalities in the LOC and right FG are more specific to behavioral features of the BAP. Results extend our knowledge of neural circuitry underlying abnormal face processing beyond those previously reported in ASD to individuals with shared genetic liability for autism and a subset of genetically related individuals with the BAP. PMID:25056573

Pathology of idiopathic non-cirrhotic portal hypertension.

PubMed

Guido, Maria; Sarcognato, Samantha; Sacchi, Diana; Colloredo, Guido

2018-04-12

Idiopathic non-cirrhotic portal hypertension is an under-recognized vascular liver disease of unknown etiology, characterized by clinical signs of portal hypertension in the absence of cirrhosis. By definition, any disorder known to cause portal hypertension in the absence of cirrhosis and any cause of chronic liver disease must be excluded to make a diagnosis of idiopathic non-cirrhotic portal hypertension. However, the diagnosis is often difficult because the disease resembles cirrhosis and there is no gold standard test. Liver biopsy is an essential tool: it is able to exclude cirrhosis and other causes of portal hypertension and it allows the identification of the characteristic lesions. Nonetheless, the histological diagnosis of idiopathic non-cirrhotic portal hypertension is not always straightforward, in particular by needle biopsy samples, because there is no pathognomonic lesion, but rather a variety of vascular changes which are unevenly distributed, very subtle, and not all necessarily identified in a single specimen. Pathologists should be able to recognize several patterns of injury, involving portal/periportal areas as well as parenchymal structures.The histological features of idiopathic non-cirrhotic portal hypertension are described in this review, focusing on their interpretation in needle biopsy specimens.

Joint seismic data denoising and interpolation with double-sparsity dictionary learning

NASA Astrophysics Data System (ADS)

Zhu, Lingchen; Liu, Entao; McClellan, James H.

2017-08-01

Seismic data quality is vital to geophysical applications, so that methods of data recovery, including denoising and interpolation, are common initial steps in the seismic data processing flow. We present a method to perform simultaneous interpolation and denoising, which is based on double-sparsity dictionary learning. This extends previous work that was for denoising only. The original double-sparsity dictionary learning algorithm is modified to track the traces with missing data by defining a masking operator that is integrated into the sparse representation of the dictionary. A weighted low-rank approximation algorithm is adopted to handle the dictionary updating as a sparse recovery optimization problem constrained by the masking operator. Compared to traditional sparse transforms with fixed dictionaries that lack the ability to adapt to complex data structures, the double-sparsity dictionary learning method learns the signal adaptively from selected patches of the corrupted seismic data, while preserving compact forward and inverse transform operators. Numerical experiments on synthetic seismic data indicate that this new method preserves more subtle features in the data set without introducing pseudo-Gibbs artifacts when compared to other directional multi-scale transform methods such as curvelets.

Hyperspectral Image Enhancement and Mixture Deep-Learning Classification of Corneal Epithelium Injuries

PubMed Central

Md Noor, Siti Salwa; Michael, Kaleena; Marshall, Stephen; Ren, Jinchang

2017-01-01

In our preliminary study, the reflectance signatures obtained from hyperspectral imaging (HSI) of normal and abnormal corneal epithelium tissues of porcine show similar morphology with subtle differences. Here we present image enhancement algorithms that can be used to improve the interpretability of data into clinically relevant information to facilitate diagnostics. A total of 25 corneal epithelium images without the application of eye staining were used. Three image feature extraction approaches were applied for image classification: (i) image feature classification from histogram using a support vector machine with a Gaussian radial basis function (SVM-GRBF); (ii) physical image feature classification using deep-learning Convolutional Neural Networks (CNNs) only; and (iii) the combined classification of CNNs and SVM-Linear. The performance results indicate that our chosen image features from the histogram and length-scale parameter were able to classify with up to 100% accuracy; particularly, at CNNs and CNNs-SVM, by employing 80% of the data sample for training and 20% for testing. Thus, in the assessment of corneal epithelium injuries, HSI has high potential as a method that could surpass current technologies regarding speed, objectivity, and reliability. PMID:29144388

Kinematic Origins of Motor Inconsistency in Expert Pianists.

PubMed

Tominaga, Kenta; Lee, André; Altenmüller, Eckart; Miyazaki, Fumio; Furuya, Shinichi

2016-01-01

For top performers, including athletes and musicians, even subtle inconsistencies in rhythm and force during movement production decrease the quality of performance. However, extensive training over many years beginning in childhood is unable to perfect dexterous motor performance so that it is without any error. To gain insight into the biological mechanisms underlying the subtle defects of motor actions, the present study sought to identify the kinematic origins of inconsistency of dexterous finger movements in musical performance. Seven highly-skilled pianists who have won prizes at international piano competitions played a short sequence of tones with the right hand at a predetermined tempo. Time-varying joint angles of the fingers were recorded using a custom-made data glove, and the timing and velocity of the individual keystrokes were recorded from a digital piano. Both ridge and stepwise multiple regression analyses demonstrated an association of the inter-trial variability of the inter-keystroke interval (i.e., rhythmic inconsistency) with both the rotational velocity of joints of the finger used for a keystroke (i.e., striking finger) and the movement independence between the striking and non-striking fingers. This indicates a relationship between rhythmic inconsistency in musical performance and the dynamic features of movements in not only the striking finger but also the non-striking fingers. In contrast, the inter-trial variability of the key-descending velocity (i.e., loudness inconsistency) was associated mostly with the kinematic features of the striking finger at the moment of the keystroke. Furthermore, there was no correlation between the rhythmic and loudness inconsistencies. The results suggest distinct kinematic origins of inconsistencies in rhythm and loudness in expert musical performance.

Fluorescent marker-based and marker-free discrimination between healthy and cancerous human tissues using hyper-spectral imaging

NASA Astrophysics Data System (ADS)

Arnold, Thomas; De Biasio, Martin; Leitner, Raimund

2015-06-01

Two problems are addressed in this paper (i) the fluorescent marker-based and the (ii) marker-free discrimination between healthy and cancerous human tissues. For both applications the performance of hyper-spectral methods are quantified. Fluorescent marker-based tissue classification uses a number of fluorescent markers to dye specific parts of a human cell. The challenge is that the emission spectra of the fluorescent dyes overlap considerably. They are, furthermore disturbed by the inherent auto-fluorescence of human tissue. This results in ambiguities and decreased image contrast causing difficulties for the treatment decision. The higher spectral resolution introduced by tunable-filter-based spectral imaging in combination with spectral unmixing techniques results in an improvement of the image contrast and therefore more reliable information for the physician to choose the treatment decision. Marker-free tissue classification is based solely on the subtle spectral features of human tissue without the use of artificial markers. The challenge in this case is that the spectral differences between healthy and cancerous tissues are subtle and embedded in intra- and inter-patient variations of these features. The contributions of this paper are (i) the evaluation of hyper-spectral imaging in combination with spectral unmixing techniques for fluorescence marker-based tissue classification, (ii) the evaluation of spectral imaging for marker-free intra surgery tissue classification. Within this paper, we consider real hyper-spectral fluorescence and endoscopy data sets to emphasize the practical capability of the proposed methods. It is shown that the combination of spectral imaging with multivariate statistical methods can improve the sensitivity and specificity of the detection and the staging of cancerous tissues compared to standard procedures.

Structural Characteristics of the Plasmid-Encoded Toxin from Enteroaggregative Escherichia coli†

PubMed Central

Scaglione, Patricia; Nemec, Kathleen N.; Burlingame, Kaitlin E.; Grabon, Agnieszka; Huerta, Jazmin; Navarro-García, Fernando; Tatulian, Suren A.; Teter, Ken

2008-01-01

Intoxication by the plasmid-encoded toxin (Pet) of enteroaggregative Escherichia coli requires toxin translocation from the endoplasmic reticulum (ER) to the cytosol. This event involves the quality control system of ER-associated degradation (ERAD), but the molecular details of the process are poorly characterized. For many structurally distinct AB-type toxins, ERAD-mediated translocation is triggered by the spontaneous unfolding of a thermally unstable A chain. Here we show that Pet, a non-AB toxin, engages ERAD by a different mechanism that does not involve thermal unfolding. Circular dichroism and fluorescence spectroscopy measurements demonstrated that Pet maintains most of its secondary and tertiary structural features at 37°C, with significant thermal unfolding only occurring at temperatures ≥50°C. Fluorescence quenching experiments detected the partial solvent exposure of Pet aromatic amino acid residues at 37°C, and a cell-based assay suggested these changes could activate an ERAD-related event known as the unfolded protein response. We also found that HEp-2 cells were resistant to Pet intoxication when incubated with glycerol, a protein stabilizer. Altogether, our data are consistent with a model in which ERAD activity is triggered by a subtle structural destabilization of Pet and the exposure of Pet hydrophobic residues at physiological temperature. This was further supported by computer modeling analysis, which identified a surface-exposed hydrophobic loop among other accessible nonpolar residues in Pet. From our data it appears that Pet can promote its ERAD-mediated translocation into the cytosol by a distinct mechanism involving partial exposure of hydrophobic residues rather than the substantial unfolding observed for certain AB toxins. PMID:18702515

One night of sleep is insufficient to achieve sleep-to-forget emotional decontextualisation processes.

PubMed

Deliens, Gaétane; Peigneux, Philippe

2014-01-01

Neutral memories unbind from their emotional acquisition context when sleep is allowed the night after learning and testing takes place after two additional nights of sleep. However, mood-dependent memory (MDM) effects are not abolished after a restricted sleep episode mostly featuring non rapid-eye-movement (NREM) or rapid-eye-movement (REM) sleep. Here, we tested whether (1) one night of sleep featuring several NREM-REM sleep cycles is sufficient to suppress MDM effects and (2) a neutral mood is a sufficiently contrasting state to induce MDM effects, i.e. interfere with the recall of information learned in happy or sad states. Results disclosed MDM effects both in the post-learning sleep and wake conditions, with better recall in congruent than incongruent emotional contexts. Our findings suggest that the emotional unbinding needs several consecutive nights of sleep to be complete, and that even subtle mood changes are sufficient to produce MDM effects.

Enhanced facial recognition for thermal imagery using polarimetric imaging.

PubMed

Gurton, Kristan P; Yuffa, Alex J; Videen, Gorden W

2014-07-01

We present a series of long-wave-infrared (LWIR) polarimetric-based thermal images of facial profiles in which polarization-state information of the image-forming radiance is retained and displayed. The resultant polarimetric images show enhanced facial features, additional texture, and details that are not present in corresponding conventional thermal imagery. It has been generally thought that conventional thermal imagery (MidIR or LWIR) could not produce the detailed spatial information required for reliable human identification due to the so-called "ghosting" effect often seen in thermal imagery of human subjects. By using polarimetric information, we are able to extract subtle surface features of the human face, thus improving subject identification. Polarimetric image sets considered include the conventional thermal intensity image, S0, the two Stokes images, S1 and S2, and a Stokes image product called the degree-of-linear-polarization image.

Metamorphosis in Teleosts

PubMed Central

McMenamin, Sarah K.; Parichy, David M.

2017-01-01

Teleosts are the largest and most diverse group of vertebrates, and many species undergo morphological, physiological, and behavioral transitions, “metamorphoses,” as they progress between morphologically divergent life stages. The larval metamorphosis that generally occurs as teleosts mature from larva to juvenile involves the loss of embryo-specific features, the development of new adult features, major remodeling of different organ systems, and changes in physical proportions and overall phenotype. Yet, in contrast to anuran amphibians, for example, teleost metamorphosis can entail morphological change that is either sudden and profound, or relatively gradual and subtle. Here, we review the definition of metamorphosis in teleosts, the diversity of teleost metamorphic strategies and the transitions they involve, and what is known of their underlying endocrine and genetic bases. We suggest that teleost metamorphosis offers an outstanding opportunity for integrating our understanding of endocrine mechanisms, cellular processes of morphogenesis and differentiation, and the evolution of diverse morphologies and life histories. PMID:23347518

New approaches to investigating social gestures in autism spectrum disorder

PubMed Central

2012-01-01

The combination of economic games and human neuroimaging presents the possibility of using economic probes to identify biomarkers for quantitative features of healthy and diseased cognition. These probes span a range of important cognitive functions, but one new use is in the domain of reciprocating social exchange with other humans - a capacity perturbed in a number of psychopathologies. We summarize the use of a reciprocating exchange game to elicit neural and behavioral signatures for subjects diagnosed with autism spectrum disorder (ASD). Furthermore, we outline early efforts to capture features of social exchange in computational models and use these to identify quantitative behavioral differences between subjects with ASD and matched controls. Lastly, we summarize a number of subsequent studies inspired by the modeling results, which suggest new neural and behavioral signatures that could be used to characterize subtle deficits in information processing during interactions with other humans. PMID:22958572

Giant left paraduodenal hernia

PubMed Central

Cundy, Thomas P; Di Marco, Aimee N; Hamady, Mohamad; Darzi, Ara

2014-01-01

Left paraduodenal hernia (LPDH) is a retrocolic internal hernia of congenital origin that develops through the fossa of Landzert, and extends into the descending mesocolon and left portion of the transverse mesocolon. It carries significant overall risk of mortality, yet delay in diagnosis is not unusual due to subtle and elusive features. Familiarisation with the embryological and anatomical features of this rare hernia is essential for surgical management. This is especially important with respect to vascular anatomy as major mesenteric vessels form intimate relationships with the ventral rim and anterior portion of the hernia. As an illustrative case, we describe our experience with a striking example of LPDH, particularly focusing on the inherent diagnostic challenges and associated critical vascular anatomy. We advocate the role of diagnostic laparoscopy; however caution that decision to safely proceed with laparoscopic repair must occur only with confident identification of the vascular anatomy involved. PMID:24792018

Subacute Sclerosing Panencephalitis in a Toddler: Changing Epidemiological Trends

PubMed Central

Aulakh, Roosy; Tiwari, Abhimanyu

2013-01-01

Subacute sclerosing panencephalitis (SSPE) is a devastating “slow virus” brain disease resulting from persistent measles virus infection of neurons. The age at presentation is usually 8 to 11 years with onset usually occurring 2–10 years after measles infection. We report a 2-and-half-year-old boy who presented with progressively increasing myoclonic jerks and subtle cognitive decline. He was diagnosed as a case of SSPE based on clinical features, typical electroencephalographic finding, and elevated cerebrospinal fluid/serum measles antibody titers. He had measles 4 months prior to onset of symptoms. This case along with review of recently published reports suggests progressively decreasing latency period between measles infection and onset of symptoms observed in cases with SSPE. Clinical implication would mean investigating for SSPE even in infants or toddlers with compatible clinical features and recent history of measles infection. PMID:24416610

Tunable alumina 2D photonic-crystal structures via biomineralization of peacock tail feathers

NASA Astrophysics Data System (ADS)

Jiang, Yonggang; Wang, Rui; Feng, Lin; Li, Jian; An, Zhonglie; Zhang, Deyuan

2018-04-01

Peacock tail feathers with subtle periodic nanostructures exhibit diverse striking brilliancy, which can be applied as natural templates to fabricate artificial photonic crystals (PhCs) via a biomineralization method. Alumina photonic-crystal structures are successfully synthesized via an immersion and two-step calcination process. The lattice constants of the artificial PhCs are greatly reduced compared to their natural matrices. The lattice constants are tunable by modifying the final annealing conditions in the biomineralization process. The reflection spectra of the alumina photonic-crystal structures are measured, which is related to their material and structural parameters. This work suggests a facile fabrication process to construct alumina PhCs with a high-temperature resistance.

Nanoscale modifications in the early heating stages of bone are heterogeneous at the microstructural scale

PubMed Central

Chadefaux, Céline; Lemaitre, Estelle; Bellot-Gurlet, Ludovic; Reynolds, Michael; Burghammer, Manfred; Plazanet, Marie; Boivin, Georges; Farlay, Delphine; Bunk, Oliver; Reiche, Ina

2017-01-01

Nanoscale studies of bone provide key indicators to evidence subtle structural changes that may occur in the biomedical, forensic and archaeological contexts. One specific problem encountered in all those disciplines, for which the identification of nanostructural cues could prove useful, is to properly monitor the effect of heating on bone tissue. In particular, the mechanisms at work at the onset of heating are still relatively unclear. Using a multiscale approach combining Raman microspectroscopy, transmission electron microscopy (TEM), synchrotron quantitative scanning small-angle X-ray scattering imaging (qsSAXSI) and polarized light (PL) microscopy, we investigate the ultrastructure of cortical bovine bone heated at temperatures < 300°C, from the molecular to the macroscopic scale. We show that, despite limited changes in crystal structure, the mineral nanoparticles increase in thickness and become strongly disorganized upon heating. Furthermore, while the nanostructure in distinct anatomical quadrants appears to be statistically different, our results demonstrate this stems from the tissue histology, i.e. from the high degree of heterogeneity of the microstructure induced by the complex cellular processes involved in bone tissue formation. From this study, we conclude that the analysis of bone samples based on the structure and organization of the mineral nanocrystals requires performing measurements at the histological level, which is an advantageous feature of qsSAXSI. This is a critical aspect that extends to a much broader range of questions relating to nanoscale investigations of bone, which could also be extended to other classes of nanostructured heterogeneous materials. PMID:28423023

Petalite under pressure: Elastic behavior and phase stability

DOE PAGES

Ross, Nancy L.; Zhao, Jing; Slebodnick, Carla; ...

2015-04-01

The lithium aluminosilicate mineral petalite (LiAlSi 4O 10) has been studied using high-pressure single-crystal X-ray diffraction (HP-XRD) up to 5 GPa. Petalite undergoes two pressure-induced first-order phase transitions, never reported in the literature, at ca. 1.5 and 2.5 GPa. The first of these transforms the low-pressure α-phase of petalite (P2/c) to an intermediate β-phase that then fully converts to the high-pressure β-phase at ca. 2.5 GPa. The α→β transition is isomorphic and is associated with a commensurate modulation that triples the unit cell volume. Analysis of the HP-XRD data show that although the fundamental features of the petalite structure aremore » retained through this transition, there are subtle alterations in the internal structure of the silicate double-layers in the β-phase relative to the α-phase. Measurement of the unit cell parameters of petalite as a function of pressure, and fitting of the data with 3rd order Birch-Murnaghan equations of state, has provided revised elastic constants for petalite. The bulk moduli of the α and β-phases are 49(1) and 35(3) GPa, respectively. These values indicate that the compressibility of the- phase of petalite lies between the alkali feldpsars and alkali feldspathoids, whereas the β-phase has a compressibility more comparable with layered silicates. Structure analysis has shown that the compression of the -phase is facilitated by the rigid body movement of the Si 2O 7 units from which the silicate double-layers are constructed.« less

Impacts of invasive plants on songbirds: Using song structure as an indicator of habitat quality

Treesearch

Yvette Ortega

2007-01-01

Invasive species can alter habitat quality over broad scales, so they pose a severe threat to songbird populations. Through our long-term research program supported by BEMRP, we have found that changes in habitat quality induced by exotic plants like spotted knapweed can lead to subtle yet profound changes in songbird populations. For example, in knapweed-invaded...

Putting time into proof outlines

NASA Technical Reports Server (NTRS)

Schneider, Fred B.; Bloom, Bard; Marzullo, Keith

1993-01-01

A logic for reasoning about timing properties of concurrent programs is presented. The logic is based on Hoare-style proof outlines and can handle maximal parallelism as well as certain resource-constrained execution environments. The correctness proof for a mutual exclusion protocol that uses execution timings in a subtle way illustrates the logic in action. A soundness proof using structural operational semantics is outlined in the appendix.

Structure of the Stern layer in Phospholipid Systems

NASA Astrophysics Data System (ADS)

Vangaveti, Sweta; Travesset, Alex

2011-03-01

The structure of the Stern layer in Phospholipid Systems results from a subtle competition of salt concentration, ionic valence, specific ionic-phospolipid interactions and pH. It becomes very challenging to develop a rigorous theory that encompasses all these effects, yet its understanding is extremely relevant for both model and biological systems, as the structure of the Stern layer determines the interactions of phospholipids with proteins or electrostatic phase separation (rafts). In this talk we will present our theoretical model for the Stern Layer and discuss how all these effects are included. Particularly emphasis is made to Phosphoinositides and Phosphatidic acid. This work is supported by grant NSF DMR-0748475.

Depression in Parkinson's disease: impediments to recognition and treatment options.

PubMed

Poewe, W; Luginger, E

1999-01-01

By some estimates, nearly half of patients with PD also suffer depression. Because features of PD frequently overlap with typical manifestations of major affective disorder (or mild dysthymia), both diagnosis and treatment of this comorbidity are challenging. Some of these interactive features include cognitive and speech deficits and impairments in emotional expression (e.g., PD-related facial masking) or processing. Parkinsonian depression probably is caused by an independent abnormality rather than as a maladaptive response to disease, in that the degree of depression is not correlated with PD severity. Prognostically, depressive features (e.g., introversion, inflexibility) may represent a subtle premorbid state heralding the onset of PD or an accelerated cognitive decline thereafter. Therapeutic mainstays for parkinsonian depression include psychosocial counseling at the time of PD diagnosis (and during advanced stages of PD) as well as appropriate medication regimens, the relative clinical efficacy of which remain a matter of ongoing clinical inquiry: levodopa, dopamine agonists, selegilene, tricyclic antidepressants, and selective serotonin reuptake inhibitors). This review formulates a rational treatment algorithm to assist in clinical management of parkinsonian depression, an enormously complex clinical entity.

Losing face: impaired discrimination of featural and configural information in the mouth region of an inverted face.

PubMed

Tanaka, James W; Kaiser, Martha D; Hagen, Simen; Pierce, Lara J

2014-05-01

Given that all faces share the same set of features-two eyes, a nose, and a mouth-that are arranged in similar configuration, recognition of a specific face must depend on our ability to discern subtle differences in its featural and configural properties. An enduring question in the face-processing literature is whether featural or configural information plays a larger role in the recognition process. To address this question, the face dimensions task was designed, in which the featural and configural properties in the upper (eye) and lower (mouth) regions of a face were parametrically and independently manipulated. In a same-different task, two faces were sequentially presented and tested in their upright or in their inverted orientation. Inversion disrupted the perception of featural size (Exp. 1), featural shape (Exp. 2), and configural changes in the mouth region, but it had relatively little effect on the discrimination of featural size and shape and configural differences in the eye region. Inversion had little effect on the perception of information in the top and bottom halves of houses (Exp. 3), suggesting that the lower-half impairment was specific to faces. Spatial cueing to the mouth region eliminated the inversion effect (Exp. 4), suggesting that participants have a bias to attend to the eye region of an inverted face. The collective findings from these experiments suggest that inversion does not differentially impair featural or configural face perceptions, but rather impairs the perception of information in the mouth region of the face.

Derivative component analysis for mass spectral serum proteomic profiles.

PubMed

Han, Henry

2014-01-01

As a promising way to transform medicine, mass spectrometry based proteomics technologies have seen a great progress in identifying disease biomarkers for clinical diagnosis and prognosis. However, there is a lack of effective feature selection methods that are able to capture essential data behaviors to achieve clinical level disease diagnosis. Moreover, it faces a challenge from data reproducibility, which means that no two independent studies have been found to produce same proteomic patterns. Such reproducibility issue causes the identified biomarker patterns to lose repeatability and prevents it from real clinical usage. In this work, we propose a novel machine-learning algorithm: derivative component analysis (DCA) for high-dimensional mass spectral proteomic profiles. As an implicit feature selection algorithm, derivative component analysis examines input proteomics data in a multi-resolution approach by seeking its derivatives to capture latent data characteristics and conduct de-noising. We further demonstrate DCA's advantages in disease diagnosis by viewing input proteomics data as a profile biomarker via integrating it with support vector machines to tackle the reproducibility issue, besides comparing it with state-of-the-art peers. Our results show that high-dimensional proteomics data are actually linearly separable under proposed derivative component analysis (DCA). As a novel multi-resolution feature selection algorithm, DCA not only overcomes the weakness of the traditional methods in subtle data behavior discovery, but also suggests an effective resolution to overcoming proteomics data's reproducibility problem and provides new techniques and insights in translational bioinformatics and machine learning. The DCA-based profile biomarker diagnosis makes clinical level diagnostic performances reproducible across different proteomic data, which is more robust and systematic than the existing biomarker discovery based diagnosis. Our findings demonstrate the feasibility and power of the proposed DCA-based profile biomarker diagnosis in achieving high sensitivity and conquering the data reproducibility issue in serum proteomics. Furthermore, our proposed derivative component analysis suggests the subtle data characteristics gleaning and de-noising are essential in separating true signals from red herrings for high-dimensional proteomic profiles, which can be more important than the conventional feature selection or dimension reduction. In particular, our profile biomarker diagnosis can be generalized to other omics data for derivative component analysis (DCA)'s nature of generic data analysis.

Frustration in Biomolecules

PubMed Central

Ferreiro, Diego U.; Komives, Elizabeth A.; Wolynes, Peter G.

2014-01-01

Biomolecules are the prime information processing elements of living matter. Most of these inanimate systems are polymers that compute their own structures and dynamics using as input seemingly random character strings of their sequence, following which they coalesce and perform integrated cellular functions. In large computational systems with a finite interaction-codes, the appearance of conflicting goals is inevitable. Simple conflicting forces can lead to quite complex structures and behaviors, leading to the concept of frustration in condensed matter. We present here some basic ideas about frustration in biomolecules and how the frustration concept leads to a better appreciation of many aspects of the architecture of biomolecules, and how biomolecular structure connects to function. These ideas are simultaneously both seductively simple and perilously subtle to grasp completely. The energy landscape theory of protein folding provides a framework for quantifying frustration in large systems and has been implemented at many levels of description. We first review the notion of frustration from the areas of abstract logic and its uses in simple condensed matter systems. We discuss then how the frustration concept applies specifically to heteropolymers, testing folding landscape theory in computer simulations of protein models and in experimentally accessible systems. Studying the aspects of frustration averaged over many proteins provides ways to infer energy functions useful for reliable structure prediction. We discuss how frustration affects folding mechanisms. We review here how a large part of the biological functions of proteins are related to subtle local physical frustration effects and how frustration influences the appearance of metastable states, the nature of binding processes, catalysis and allosteric transitions. We hope to illustrate how Frustration is a fundamental concept in relating function to structural biology. PMID:25225856

Crystal Structures of Penicillin-Binding Protein 2 From Penicillin-Susceptible And -Resistant Strains of Neisseria Gonorrhoeae Reveal An Unexpectedly Subtle Mechanism for Antibiotic Resistance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Powell, A.J.; Tomberg, J.; Deacon, A.M.

Penicillin-binding protein 2 (PBP2) from N. gonorrhoeae is the major molecular target for {beta}-lactam antibiotics used to treat gonococcal infections. PBP2 from penicillin-resistant strains of N. gonorrhoeae harbors an aspartate insertion after position 345 (Asp-345a) and 4-8 additional mutations, but how these alter the architecture of the protein is unknown. We have determined the crystal structure of PBP2 derived from the penicillin-susceptible strain FA19, which shows that the likely effect of Asp-345a is to alter a hydrogen-bonding network involving Asp-346 and the SXN triad at the active site. We have also solved the crystal structure of PBP2 derived from themore » penicillin-resistant strain FA6140 that contains four mutations near the C terminus of the protein. Although these mutations lower the second order rate of acylation for penicillin by 5-fold relative to wild type, comparison of the two structures shows only minor structural differences, with the positions of the conserved residues in the active site essentially the same in both. Kinetic analyses indicate that two mutations, P551S and F504L, are mainly responsible for the decrease in acylation rate. Melting curves show that the four mutations lower the thermal stability of the enzyme. Overall, these data suggest that the molecular mechanism underlying antibiotic resistance contributed by the four mutations is subtle and involves a small but measurable disordering of residues in the active site region that either restricts the binding of antibiotic or impedes conformational changes that are required for acylation by {beta}-lactam antibiotics.« less

Interactions and reversal-field memory in complex magnetic nanowire arrays

NASA Astrophysics Data System (ADS)

Rotaru, Aurelian; Lim, Jin-Hee; Lenormand, Denny; Diaconu, Andrei; Wiley, John. B.; Postolache, Petronel; Stancu, Alexandru; Spinu, Leonard

2011-10-01

Interactions and magnetization reversal of Ni nanowire arrays have been investigated by the first-order reversal curve (FORC) method. Several series of samples with controlled spatial distribution were considered including simple wires of different lengths and diameters (70 and 110 nm) and complex wires with a single modulated diameter along their length. Subtle features of magnetic interactions are revealed through a quantitative analysis of the local interaction field profile distributions obtained from the FORC method. In addition, the FORC analysis indicates that the nanowire systems with a mean diameter of 70 nm appear to be organized in symmetric clusters indicative of a reversal-field memory effect.

Metrologically useful states of spin-1 Bose condensates with macroscopic magnetization

NASA Astrophysics Data System (ADS)

Kajtoch, Dariusz; Pawłowski, Krzysztof; Witkowska, Emilia

2018-02-01

We study theoretically the usefulness of spin-1 Bose condensates with macroscopic magnetization in a homogeneous magnetic field for quantum metrology. We demonstrate Heisenberg scaling of the quantum Fisher information for states in thermal equilibrium. The scaling applies to both antiferromagnetic and ferromagnetic interactions. The effect preserves as long as fluctuations of magnetization are sufficiently small. Scaling of the quantum Fisher information with the total particle number is derived within the mean-field approach in the zero-temperature limit and exactly in the high-magnetic-field limit for any temperature. The precision gain is intuitively explained owing to subtle features of the quasidistribution function in the phase space.

Biomedical perspectives on locomotion in null gravity

NASA Technical Reports Server (NTRS)

Cavanagh, Peter R.

1989-01-01

A number of important features of various locomotor activities are discussed, and approaches to the study of these activities in the context of space flight are suggested. In particular, the magnitude of peak forces and the rates of change of force during terrestrial cycling, walking, and running are compared. It is shown that subtle changes in the conditions and techniques of locomotion can have a major influence on the biomechanical consequences to the skeleton. The various hypotheses that identify locomotor exercise as a countermeasure to bone demineralization during weightlessness deserve to be tested with some degree of biomechanical rigor. Various approaches for achieving such scrutiny are discussed.

Traumatic injuries of the diaphragm: overview of imaging findings and diagnosis.

PubMed

Hammer, Mark M; Raptis, Demetrios A; Mellnick, Vincent M; Bhalla, Sanjeev; Raptis, Constantine A

2017-04-01

Injuries to the diaphragm muscle occur in penetrating and severe blunt trauma and can lead to delayed hernia formation. Computed tomography is the mainstay in the diagnosis of these injuries, which may be subtle at presentation. Imaging findings differ between blunt and penetrating trauma. Key features in blunt trauma include diaphragm fragment distraction and organ herniation because of increased intra-abdominal pressure. In penetrating trauma, herniation is uncommon, and the trajectory of the object is critical in making the diagnosis of diaphragm injury in these patients. Radiologists must keep a high index of suspicion for injury to the diaphragm in cases of trauma to the chest or abdomen.

Age-related reduction in microcolumnar structure correlates with cognitive decline in ventral but not dorsal area 46 of the rhesus monkey.

PubMed

Cruz, L; Roe, D L; Urbanc, B; Inglis, A; Stanley, H E; Rosene, D L

2009-02-18

The age-related decline in cognitive function that is observed in normal aging monkeys and humans occurs without significant loss of cortical neurons. This suggests that cognitive impairment results from subtle, sub-lethal changes in the cortex. Recently, changes in the structural coherence in mini- or microcolumns without loss of neurons have been linked to loss of function. Here we use a density map method to quantify microcolumnar structure in both banks of the sulcus principalis (prefrontal cortical area 46) of 16 (ventral) and 19 (dorsal) behaviorally tested female rhesus monkeys from 6 to 33 years of age. While total neuronal density does not change with age in either of these banks, there is a significant age-related reduction in the strength of microcolumns in both regions on the order of 40%. This likely reflects a subtle but definite loss of organization in the structure of the cortical microcolumn. The reduction in strength in ventral area 46 correlates with cognitive impairments in learning and memory while the reduction in dorsal area 46 does not. This result is congruent with published data attributing cognitive functions to ventral area 46 that are similar to our particular cognitive battery which does not optimally tap cognitive functions attributed to dorsal area 46. While the exact mechanisms underlying this loss of microcolumnar organization remain to be determined, it is plausible that they reflect age-related alterations in dendritic and/or axonal organization which alter connectivity and may contribute to age-related declines in cognitive performance.

Familiarity of Alpine magnitude and geometry as a critical pedagogic element in student visualisation of basin- & crustal-scale sub-surface structure

NASA Astrophysics Data System (ADS)

Edwards, M. A.

2004-12-01

A geoscience education stumbling block that typically re-currs throughout the early years of student progress is bringing three dimensional spatial scales of Earth's features in perspective. This far more so than temporal scales; the concept of geological timescale is normally quickly adopted into a students perception. Providing a sense of proportion for three dimensional objects is two fold: the first, the actual "thinking in 3D" while often depicting in 2D (e.g. seismic moment "beachballs", stereonets, cross-sections, atmospheric circulation cells) has been dramatically assisted by accelerated graphics imaging software. The second, proportion across all scales, is subtle yet crucial and not necessarily better-conveyed to students exclusively via computer-assisted learning. My experiences teaching students from a range of geographical backgrounds strongly indicates a much firmer grasp overall, by students from Alpine regions, of magnitudes and scales of crustal features. The intensity of topography in these regions, where cablecar and steep walking are the primary accesses, is a unique opportunity to illustrate the km-scale of structures in 3D, a lesson far beyond one of simply illustrating the appearance of typical rocks "in the great outdoors" and very tricky to convery through "virtual" field trips alone. Examples include; 1. the embodiment of a shallow seismic reflection profile to a several hundrend metre cliff of intercalated (i.e. switching impedance contrast) turbidites whose km-long overthrust line is traceable along a valley floor far below. 2. the weight of the thrust pile underfoot and corresponding amounts of lithosphere bending and foreland basin growth - a perspective often lost with beam engineering-only approaches. 3. fluid-volumes: intensely solution-strained &/or vein-bearing masses can be estimated for volume percentage and total cubic amount across a mountain region. 4. instantaneous river bedload versus yearly versus m.y. total volumes. Such 3D realism is crucial is subsurface modelling of hydrocarbon/water/waste potentials.

Crystal Structure of the Dimeric Oct6 (Pou3fl) POU Domain Bound to Palindromic MORE DNA

DOE Office of Scientific and Technical Information (OSTI.GOV)

R Jauch; S Choo; C Ng

POU domains (named after their identification in Pit1, Oct1 unc86) are found in around 15 transcription factors encoded in mammalian genomes many of which feature prominently as key regulators at development bifurcations. For example, the POU III class Octamer binding protein 6 (Oct6) is expressed in embryonic stem cells and during neural development and drives the differentia5tion of myelinated cells in the central and peripheral nervous system. Defects in oct6 expression levels are linked to neurological disorders such as schizophrenia. POU proteins contain a bi-partite DNA binding domain that assembles on various DNA motifs with differentially configured subdomains. Intriguingly, alternativemore » configurations of POU domains on different DNA sites were shown to affect the subsequent recruitment of transcriptional coactivators. Namely, binding of Oct1 to a Palindromic Oct-factor Recognition Element (PORE) was shown to facilitate the recruitment of the OBF1 coactivator whereas More of PORE (MORE) bound Oct1 does not. Moreover, Pit1 was shown to recruit the corepressor N-CoR only when bound to a variant MORE motif with a 2 bp half-site spacing. Therefore, POU proteins are seen as a paradigm for DNA induced allosteric effects on transcription factors modulating their regulatory potential. However, a big unresolved conundrum for the POU class and for most if not all other transcription factor classes is how highly similar proteins regulate different sets of genes causing fundamentally different biological responses. Ultimately, there must be subtle features enabling those factors to engage in contrasting molecular interactions in the cell. Thus, the dissection of the molecular details of the transcription-DNA recognition in general, and the formation of multimeric regulatory complexes, in particular, is highly desirable. To contribute to these efforts they solved the 2.05 {angstrom} crystal structure of Oct6 bound as a symmetrical homodimer to palindromic MORE DNA.« less

The Richness of Task-Evoked Hemodynamic Responses Defines a Pseudohierarchy of Functionally Meaningful Brain Networks

PubMed Central

Orban, Pierre; Doyon, Julien; Petrides, Michael; Mennes, Maarten; Hoge, Richard; Bellec, Pierre

2015-01-01

Functional magnetic resonance imaging can measure distributed and subtle variations in brain responses associated with task performance. However, it is unclear whether the rich variety of responses observed across the brain is functionally meaningful and consistent across individuals. Here, we used a multivariate clustering approach that grouped brain regions into clusters based on the similarity of their task-evoked temporal responses at the individual level, and then established the spatial consistency of these individual clusters at the group level. We observed a stable pseudohierarchy of task-evoked networks in the context of a delayed sequential motor task, where the fractionation of networks was driven by a gradient of involvement in motor sequence preparation versus execution. In line with theories about higher-level cognitive functioning, this gradient evolved in a rostro-caudal manner in the frontal lobe. In addition, parcellations in the cerebellum and basal ganglia matched with known anatomical territories and fiber pathways with the cerebral cortex. These findings demonstrate that subtle variations in brain responses associated with task performance are systematic enough across subjects to define a pseudohierarchy of task-evoked networks. Such networks capture meaningful functional features of brain organization as shaped by a given cognitive context. PMID:24729172

Cataplectic facies: clinical marker in the diagnosis of childhood narcolepsy-report of two cases.

PubMed

Prasad, Manish; Setty, Gururaj; Ponnusamy, Athi; Hussain, Nahin; Desurkar, Archana

2014-05-01

Narcolepsy is a chronic disease and is commonly diagnosed in adulthood. However, more than half of the patients have onset of symptoms in childhood and/or adolescence. The full spectrum of clinical manifestations, namely excessive daytime sleepiness, cataplexy, hypnagogic hallucinations, and sleep paralysis, is usually not present at disease onset, delaying diagnosis during childhood. Mean delay in diagnosis since symptom onset is known to be several years. Initial manifestations can sometimes be as subtle as only partial drooping of eyelids leading to confusion with a myasthenic condition. We present two children who presented with "cataplectic facies," an unusual facial feature only recently described in children with narcolepsy with cataplexy. The diagnosis of narcolepsy was confirmed by multiple sleep latency test along with human leukocyte antigen typing and cerebrospinal fluid hypocretin assay. The diagnosis of narcolepsy with cataplexy at onset can be challenging in young children. With more awareness of subtle signs such as cataplectic facies, earlier diagnosis is possible. To date, only 11 children between 6 and 18 years of age presenting with typical cataplectic facies have been reported in the literature. We present two patients, one of whom is the youngest individual (4 years old) yet described with the typical cataplectic facies. Copyright © 2014 Elsevier Inc. All rights reserved.

Johnson-McMillin syndrome, a neuroectodermal syndrome with conductive hearing loss and microtia: report of a new case.

PubMed

Schweitzer, Daniela N; Yano, Shoji; Earl, Dawn L; Graham, John M

2003-07-30

In 1983, Johnson et al. described 16 related individuals with alopecia, anosmia or hyposmia, conductive hearing loss, microtia and/or atresia of the external auditory canal, and hypogonadotrophic hypogonadism inherited in an autosomal dominant pattern. Other less constant manifestations included facial asymmetry, mental retardation, congenital heart defect, cleft palate, and choanal stenosis. An isolated case was reported later (Johnston et al. [1987: Am J Med Genet 26: 925-927]) and thereafter an affected mother and son (Hennekam and Holtus [1993: Am J Med Genet 47: 714-716]). We describe an additional unrelated female patient with features resembling those of the previously reported cases. She presented with intrauterine growth deficiency, microcephaly, alopecia, bilateral microtia with canal atresia, conductive hearing loss, partial left facial palsy, posterior cleft palate, left choanal stenosis, tetralogy of Fallot, developmental delay, and right thumb polydactyly. Because the phenotypic abnormalities in this syndrome affect the brain, facial structures, ectoderm and its derivatives, outflow tract of the heart, and Rathke's pouch derivatives, this has suggested to previous authors etiologic involvement of the ectoderm and neuroectoderm of the first and second branchial arches, Rathke's pouch, and the diencephalon. Microtia with conductive hearing loss differentiates the condition from other ectodermal dysplasias. In the initial report, females appeared somewhat less affected than males, and there was male-to-male transmission. The mother of our patient manifests subtle features, which suggest she may be a mildly affected female. Additionally, there is a family history of early-onset alopecia in the maternal grandfather's relatives. Copyright 2003 Wiley-Liss, Inc.

Macromolecular Crystal Quality

NASA Technical Reports Server (NTRS)

Snell, Edward H.; Borgstahl, Gloria E. O.; Bellamy, Henry D.; Curreri, Peter A. (Technical Monitor)

2001-01-01

There are many ways of judging a good crystal. Which we use depends on the qualities we seek. For gemstones size, clarity and impurity levels (color) are paramount. For the semiconductor industry purity is probably the most important quality. For the structural crystallographer the primary desideratum is the somewhat more subtle concept of internal order. In this chapter we discuss the effect of internal order (or the lack of it) on the crystal's diffraction properties.

BcL-xL Conformational Changes upon Fragment Binding Revealed by NMR

PubMed Central

Aguirre, Clémentine; ten Brink, Tim; Walker, Olivier; Guillière, Florence; Davesne, Dany; Krimm, Isabelle

2013-01-01

Protein-protein interactions represent difficult but increasingly important targets for the design of therapeutic compounds able to interfere with biological processes. Recently, fragment-based strategies have been proposed as attractive approaches for the elaboration of protein-protein surface inhibitors from fragment-like molecules. One major challenge in targeting protein-protein interactions is related to the structural adaptation of the protein surface upon molecular recognition. Methods capable of identifying subtle conformational changes of proteins upon fragment binding are therefore required at the early steps of the drug design process. In this report we present a fast NMR method able to probe subtle conformational changes upon fragment binding. The approach relies on the comparison of experimental fragment-induced Chemical Shift Perturbation (CSP) of amine protons to CSP simulated for a set of docked fragment poses, considering the ring-current effect from fragment binding. We illustrate the method by the retrospective analysis of the complex between the anti-apoptotic Bcl-xL protein and the fragment 4′-fluoro-[1,1′-biphenyl]-4-carboxylic acid that was previously shown to bind one of the Bcl-xL hot spots. The CSP-based approach shows that the protein undergoes a subtle conformational rearrangement upon interaction, for residues located in helices 2, 3 and the very beginning of 5. Our observations are corroborated by residual dipolar coupling measurements performed on the free and fragment-bound forms of the Bcl-xL protein. These NMR-based results are in total agreement with previous molecular dynamic calculations that evidenced a high flexibility of Bcl-xL around the binding site. Here we show that CSP of protein amine protons are useful and reliable structural probes. Therefore, we propose to use CSP simulation to assess protein conformational changes upon ligand binding in the fragment-based drug design approach. PMID:23717610

Detection of urea-induced internal denaturation of dsDNA using solid-state nanopores.

PubMed

Singer, Alon; Kuhn, Heiko; Frank-Kamenetskii, Maxim; Meller, Amit

2010-11-17

The ability to detect and measure dsDNA thermal fluctuations is of immense importance in understanding the underlying mechanisms responsible for transcription and replication regulation. We describe here the ability of solid-state nanopores to detect sub-nanometer changes in DNA structure as a result of chemically enhanced thermal fluctuations. In this study, we investigate the subtle changes in the mean effective diameter of a dsDNA molecule with 3-5 nm solid-state nanopores as a function of urea concentration and the DNA's AT content. Our studies reveal an increase in the mean effective diameter of a DNA molecule of approximately 0.6 nm at 8.7 M urea. In agreement with the mechanism of DNA local denaturation, we observe a sigmoid dependence of these effects on urea concentration. We find that the translocation times in urea are markedly slower than would be expected if the dynamics were governed primarily by viscous effects. Furthermore, we find that the sensitivity of the nanopore is sufficient to statistically differentiate between DNA molecules of nearly identical lengths differing only in sequence and AT content when placed in 3.5 M urea. Our results demonstrate that nanopores can detect subtle structural changes and are thus a valuable tool for detecting differences in biomolecules' environment.

Development and evaluation of a computer-aided diagnostic scheme for lung nodule detection in chest radiographs by means of two-stage nodule enhancement with support vector classification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen Sheng; Suzuki, Kenji; MacMahon, Heber

2011-04-15

Purpose: To develop a computer-aided detection (CADe) scheme for nodules in chest radiographs (CXRs) with a high sensitivity and a low false-positive (FP) rate. Methods: The authors developed a CADe scheme consisting of five major steps, which were developed for improving the overall performance of CADe schemes. First, to segment the lung fields accurately, the authors developed a multisegment active shape model. Then, a two-stage nodule-enhancement technique was developed for improving the conspicuity of nodules. Initial nodule candidates were detected and segmented by using the clustering watershed algorithm. Thirty-one shape-, gray-level-, surface-, and gradient-based features were extracted from each segmentedmore » candidate for determining the feature space, including one of the new features based on the Canny edge detector to eliminate a major FP source caused by rib crossings. Finally, a nonlinear support vector machine (SVM) with a Gaussian kernel was employed for classification of the nodule candidates. Results: To evaluate and compare the scheme to other published CADe schemes, the authors used a publicly available database containing 140 nodules in 140 CXRs and 93 normal CXRs. The CADe scheme based on the SVM classifier achieved sensitivities of 78.6% (110/140) and 71.4% (100/140) with averages of 5.0 (1165/233) FPs/image and 2.0 (466/233) FPs/image, respectively, in a leave-one-out cross-validation test, whereas the CADe scheme based on a linear discriminant analysis classifier had a sensitivity of 60.7% (85/140) at an FP rate of 5.0 FPs/image. For nodules classified as ''very subtle'' and ''extremely subtle,'' a sensitivity of 57.1% (24/42) was achieved at an FP rate of 5.0 FPs/image. When the authors used a database developed at the University of Chicago, the sensitivities was 83.3% (40/48) and 77.1% (37/48) at an FP rate of 5.0 (240/48) FPs/image and 2.0 (96/48) FPs /image, respectively. Conclusions: These results compare favorably to those described for other commercial and noncommercial CADe nodule detection systems.« less

Culture Wires the Brain: A Cognitive Neuroscience Perspective

PubMed Central

Park, Denise C.; Huang, Chih-Mao

2012-01-01

There is clear evidence that sustained experiences may affect both brain structure and function. Thus, it is quite reasonable to posit that sustained exposure to a set of cultural experiences and behavioral practices will affect neural structure and function. The burgeoning field of cultural psychology has often demonstrated the subtle differences in the way individuals process information—differences that appear to be a product of cultural experiences. We review evidence that the collectivistic and individualistic biases of East Asian and Western cultures, respectively, affect neural structure and function. We conclude that there is limited evidence that cultural experiences affect brain structure and considerably more evidence that neural function is affected by culture, particularly activations in ventral visual cortex—areas associated with perceptual processing. PMID:22866061

Study of the incidence and nature of "very subtle epidermal melasma" in relation to intense pulsed light treatment.

PubMed

Negishi, Kei; Kushikata, Nobuharu; Tezuka, Yukiko; Takeuchi, Kaori; Miyamoto, Eiko; Wakamatsu, Shingo

2004-06-01

Skin rejuvenation with intense pulsed light (IPL) is effective for clearing epidermal pigment disorders. Complications are mild and limited to epidermal burns caused by excessive settings. Some patients, however, experience IPL-induced melasma-like hyperpigmentation despite the appearance of normal skin. These patients seem to have very subtle epidermal melasma not visible to the naked eye. Ultraviolet photography has been useful in identifying these patients and preventing complications. The study investigated the incidence of very subtle melasma in patients using UV photography, and assessed this tool in identifying high-risk patients. 223 Japanese women, 30-69 years old, participated in the study. Very subtle melasma invisible to the naked eye under normal light was diagnosed by UV photography by two physicians, and any relationship among the disease incidence, age, and regular sunscreen use was examined. Sixty-three cases of very subtle melasma (28.3%) were identified among the 223 subjects, with a significantly lower incidence in sunscreen users. Patients diagnosed with subtle epidermal melasma and treated with mild IPL parameters did not suffer induced secondary hyperpigmentaion. To help avoid complications after treatment, IPL users should be aware of the age and sunscreen-related incidence of this phenomenon in Asian patients.

Hollow-structured mesoporous materials: chemical synthesis, functionalization and applications.

PubMed

Li, Yongsheng; Shi, Jianlin

2014-05-28

Hollow-structured mesoporous materials (HMMs), as a kind of mesoporous material with unique morphology, have been of great interest in the past decade because of the subtle combination of the hollow architecture with the mesoporous nanostructure. Benefitting from the merits of low density, large void space, large specific surface area, and, especially, the good biocompatibility, HMMs present promising application prospects in various fields, such as adsorption and storage, confined catalysis when catalytically active species are incorporated in the core and/or shell, controlled drug release, targeted drug delivery, and simultaneous diagnosis and therapy of cancers when the surface and/or core of the HMMs are functionalized with functional ligands and/or nanoparticles, and so on. In this review, recent progress in the design, synthesis, functionalization, and applications of hollow mesoporous materials are discussed. Two main synthetic strategies, soft-templating and hard-templating routes, are broadly sorted and described in detail. Progress in the main application aspects of HMMs, such as adsorption and storage, catalysis, and biomedicine, are also discussed in detail in this article, in terms of the unique features of the combined large void space in the core and the mesoporous network in the shell. Functionalization of the core and pore/outer surfaces with functional organic groups and/or nanoparticles, and their performance, are summarized in this article. Finally, an outlook of their prospects and challenges in terms of their controlled synthesis and scaled application is presented. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Influence of an amorphous wall on the distribution of localized excitations in a colloidal glass-forming liquid

NASA Astrophysics Data System (ADS)

Gokhale, Shreyas; Hima Nagamanasa, K.; Sood, A. K.; Ganapathy, Rajesh

2016-07-01

Elucidating the nature of the glass transition has been the holy grail of condensed matter physics and statistical mechanics for several decades. A phenomenological aspect that makes glass formation a conceptually formidable problem is that structural and dynamic correlations in glass-forming liquids are too subtle to be captured at the level of conventional two-point functions. As a consequence, a host of theoretical techniques, such as quenched amorphous configurations of particles, have been devised and employed in simulations and colloid experiments to gain insights into the mechanisms responsible for these elusive correlations. Very often, though, the analysis of spatio-temporal correlations is performed in the context of a single theoretical framework, and critical comparisons of microscopic predictions of competing theories are thereby lacking. Here, we address this issue by analysing the distribution of localized excitations, which are building blocks of relaxation as per the dynamical facilitation (DF) theory, in the presence of an amorphous wall, a construct motivated by the random first-order transition theory (RFOT). We observe that spatial profiles of the concentration of excitations exhibit complex features such as non-monotonicity and oscillations. Moreover, the smoothly varying part of the concentration profile yields a length scale {ξc} , which we compare with a previously computed length scale {ξ\\text{dyn}} . Our results suggest a method to assess the role of dynamical facilitation in governing structural relaxation in glass-forming liquids.

Drosophila FoxP Mutants Are Deficient in Operant Self-Learning

PubMed Central

Mendoza, Ezequiel; Colomb, Julien; Rybak, Jürgen; Pflüger, Hans-Joachim; Zars, Troy

2014-01-01

Intact function of the Forkhead Box P2 (FOXP2) gene is necessary for normal development of speech and language. This important role has recently been extended, first to other forms of vocal learning in animals and then also to other forms of motor learning. The homology in structure and in function among the FoxP gene members raises the possibility that the ancestral FoxP gene may have evolved as a crucial component of the neural circuitry mediating motor learning. Here we report that genetic manipulations of the single Drosophila orthologue, dFoxP, disrupt operant self-learning, a form of motor learning sharing several conceptually analogous features with language acquisition. Structural alterations of the dFoxP locus uncovered the role of dFoxP in operant self-learning and habit formation, as well as the dispensability of dFoxP for operant world-learning, in which no motor learning occurs. These manipulations also led to subtle alterations in the brain anatomy, including a reduced volume of the optic glomeruli. RNAi-mediated interference with dFoxP expression levels copied the behavioral phenotype of the mutant flies, even in the absence of mRNA degradation. Our results provide evidence that motor learning and language acquisition share a common ancestral trait still present in extant invertebrates, manifest in operant self-learning. This ‘deep’ homology probably traces back to before the split between vertebrate and invertebrate animals. PMID:24964149

Hierarchical structure of the Sicilian goats revealed by Bayesian analyses of microsatellite information.

PubMed

Siwek, M; Finocchiaro, R; Curik, I; Portolano, B

2011-02-01

Genetic structure and relationship amongst the main goat populations in Sicily (Girgentana, Derivata di Siria, Maltese and Messinese) were analysed using information from 19 microsatellite markers genotyped on 173 individuals. A posterior Bayesian approach implemented in the program STRUCTURE revealed a hierarchical structure with two clusters at the first level (Girgentana vs. Messinese, Derivata di Siria and Maltese), explaining 4.8% of variation (amovaФ(ST) estimate). Seven clusters nested within these first two clusters (further differentiations of Girgentana, Derivata di Siria and Maltese), explaining 8.5% of variation (amovaФ(SC) estimate). The analyses and methods applied in this study indicate their power to detect subtle population structure. © 2010 The Authors, Animal Genetics © 2010 Stichting International Foundation for Animal Genetics.

Structural Insights into Functional Overlapping and Differentiation among Myosin V Motors*

PubMed Central

Nascimento, Andrey F. Z.; Trindade, Daniel M.; Tonoli, Celisa C. C.; de Giuseppe, Priscila O.; Assis, Leandro H. P.; Honorato, Rodrigo V.; de Oliveira, Paulo S. L.; Mahajan, Pravin; Burgess-Brown, Nicola A.; von Delft, Frank; Larson, Roy E.; Murakami, Mario T.

2013-01-01

Myosin V (MyoV) motors have been implicated in the intracellular transport of diverse cargoes including vesicles, organelles, RNA-protein complexes, and regulatory proteins. Here, we have solved the cargo-binding domain (CBD) structures of the three human MyoV paralogs (Va, Vb, and Vc), revealing subtle structural changes that drive functional differentiation and a novel redox mechanism controlling the CBD dimerization process, which is unique for the MyoVc subclass. Moreover, the cargo- and motor-binding sites were structurally assigned, indicating the conservation of residues involved in the recognition of adaptors for peroxisome transport and providing high resolution insights into motor domain inhibition by CBD. These results contribute to understanding the structural requirements for cargo transport, autoinhibition, and regulatory mechanisms in myosin V motors. PMID:24097982

Feature saliency and feedback information interactively impact visual category learning

PubMed Central

Hammer, Rubi; Sloutsky, Vladimir; Grill-Spector, Kalanit

2015-01-01

Visual category learning (VCL) involves detecting which features are most relevant for categorization. VCL relies on attentional learning, which enables effectively redirecting attention to object’s features most relevant for categorization, while ‘filtering out’ irrelevant features. When features relevant for categorization are not salient, VCL relies also on perceptual learning, which enables becoming more sensitive to subtle yet important differences between objects. Little is known about how attentional learning and perceptual learning interact when VCL relies on both processes at the same time. Here we tested this interaction. Participants performed VCL tasks in which they learned to categorize novel stimuli by detecting the feature dimension relevant for categorization. Tasks varied both in feature saliency (low-saliency tasks that required perceptual learning vs. high-saliency tasks), and in feedback information (tasks with mid-information, moderately ambiguous feedback that increased attentional load, vs. tasks with high-information non-ambiguous feedback). We found that mid-information and high-information feedback were similarly effective for VCL in high-saliency tasks. This suggests that an increased attentional load, associated with the processing of moderately ambiguous feedback, has little effect on VCL when features are salient. In low-saliency tasks, VCL relied on slower perceptual learning; but when the feedback was highly informative participants were able to ultimately attain the same performance as during the high-saliency VCL tasks. However, VCL was significantly compromised in the low-saliency mid-information feedback task. We suggest that such low-saliency mid-information learning scenarios are characterized by a ‘cognitive loop paradox’ where two interdependent learning processes have to take place simultaneously. PMID:25745404

Characterization of subtle brain abnormalities in a mouse model of Hedgehog pathway antagonist-induced cleft lip and palate.

PubMed

Lipinski, Robert J; Holloway, Hunter T; O'Leary-Moore, Shonagh K; Ament, Jacob J; Pecevich, Stephen J; Cofer, Gary P; Budin, Francois; Everson, Joshua L; Johnson, G Allan; Sulik, Kathleen K

2014-01-01

Subtle behavioral and cognitive deficits have been documented in patient cohorts with orofacial clefts (OFCs). Recent neuroimaging studies argue that these traits are associated with structural brain abnormalities but have been limited to adolescent and adult populations where brain plasticity during infancy and childhood may be a confounding factor. Here, we employed high resolution magnetic resonance microscopy to examine primary brain morphology in a mouse model of OFCs. Transient in utero exposure to the Hedgehog (Hh) signaling pathway antagonist cyclopamine resulted in a spectrum of facial dysmorphology, including unilateral and bilateral cleft lip and palate, cleft of the secondary palate only, and a non-cleft phenotype marked by midfacial hypoplasia. Relative to controls, cyclopamine-exposed fetuses exhibited volumetric differences in several brain regions, including hypoplasia of the pituitary gland and olfactory bulbs, hyperplasia of the forebrain septal region, and expansion of the third ventricle. However, in affected fetuses the corpus callosum was intact and normal division of the forebrain was observed. This argues that temporally-specific Hh signaling perturbation can result in typical appearing OFCs in the absence of holoprosencephaly--a condition classically associated with Hh pathway inhibition and frequently co-occurring with OFCs. Supporting the premise that some forms of OFCs co-occur with subtle brain malformations, these results provide a possible ontological basis for traits identified in clinical populations. They also argue in favor of future investigations into genetic and/or environmental modulation of the Hh pathway in the etiopathogenesis of orofacial clefting.

Local self-uniformity in photonic networks.

PubMed

Sellers, Steven R; Man, Weining; Sahba, Shervin; Florescu, Marian

2017-02-17

The interaction of a material with light is intimately related to its wavelength-scale structure. Simple connections between structure and optical response empower us with essential intuition to engineer complex optical functionalities. Here we develop local self-uniformity (LSU) as a measure of a random network's internal structural similarity, ranking networks on a continuous scale from crystalline, through glassy intermediate states, to chaotic configurations. We demonstrate that complete photonic bandgap structures possess substantial LSU and validate LSU's importance in gap formation through design of amorphous gyroid structures. Amorphous gyroid samples are fabricated via three-dimensional ceramic printing and the bandgaps experimentally verified. We explore also the wing-scale structuring in the butterfly Pseudolycaena marsyas and show that it possesses substantial amorphous gyroid character, demonstrating the subtle order achieved by evolutionary optimization and the possibility of an amorphous gyroid's self-assembly.

Structures of Rotavirus Reassortants Demonstrate Correlation of Altered Conformation of the VP4 Spike and Expression of Unexpected VP4-Associated Phenotypes

PubMed Central

Pesavento, Joseph B.; Billingsley, Angela M.; Roberts, Ed J.; Ramig, Robert F.; Prasad, B. V. Venkataram

2003-01-01

Numerous prior studies have indicated that viable rotavirus reassortants containing structural proteins of heterologous parental origin may express unexpected phenotypes, such as changes in infectivity and immunogenicity. To provide a structural basis for alterations in phenotypic expression, a three-dimensional structural analysis of these reassortants was conducted. The structures of the reassortants show that while VP4 generally maintains the parental structure when moved to a heterologous protein background, in certain reassortants, there are subtle alterations in the conformation of VP4. The alterations in VP4 conformation correlated with expression of unexpected VP4-associated phenotypes. Interactions between heterologous VP4 and VP7 in reassortants expressing unexpected phenotypes appeared to induce the conformational alterations seen in VP4. PMID:12584352

Local self-uniformity in photonic networks

NASA Astrophysics Data System (ADS)

Sellers, Steven R.; Man, Weining; Sahba, Shervin; Florescu, Marian

2017-02-01

The interaction of a material with light is intimately related to its wavelength-scale structure. Simple connections between structure and optical response empower us with essential intuition to engineer complex optical functionalities. Here we develop local self-uniformity (LSU) as a measure of a random network's internal structural similarity, ranking networks on a continuous scale from crystalline, through glassy intermediate states, to chaotic configurations. We demonstrate that complete photonic bandgap structures possess substantial LSU and validate LSU's importance in gap formation through design of amorphous gyroid structures. Amorphous gyroid samples are fabricated via three-dimensional ceramic printing and the bandgaps experimentally verified. We explore also the wing-scale structuring in the butterfly Pseudolycaena marsyas and show that it possesses substantial amorphous gyroid character, demonstrating the subtle order achieved by evolutionary optimization and the possibility of an amorphous gyroid's self-assembly.

Exploring the limits of identifying sub-pixel thermal features using ASTER TIR data

USGS Publications Warehouse

Vaughan, R.G.; Keszthelyi, L.P.; Davies, A.G.; Schneider, D.J.; Jaworowski, C.; Heasler, H.

2010-01-01

Understanding the characteristics of volcanic thermal emissions and how they change with time is important for forecasting and monitoring volcanic activity and potential hazards. Satellite instruments view volcanic thermal features across the globe at various temporal and spatial resolutions. Thermal features that may be a precursor to a major eruption, or indicative of important changes in an on-going eruption can be subtle, making them challenging to reliably identify with satellite instruments. The goal of this study was to explore the limits of the types and magnitudes of thermal anomalies that could be detected using satellite thermal infrared (TIR) data. Specifically, the characterization of sub-pixel thermal features with a wide range of temperatures is considered using ASTER multispectral TIR data. First, theoretical calculations were made to define a "thermal mixing detection threshold" for ASTER, which quantifies the limits of ASTER's ability to resolve sub-pixel thermal mixing over a range of hot target temperatures and % pixel areas. Then, ASTER TIR data were used to model sub-pixel thermal features at the Yellowstone National Park geothermal area (hot spring pools with temperatures from 40 to 90 ??C) and at Mount Erebus Volcano, Antarctica (an active lava lake with temperatures from 200 to 800 ??C). Finally, various sources of uncertainty in sub-pixel thermal calculations were quantified for these empirical measurements, including pixel resampling, atmospheric correction, and background temperature and emissivity assumptions.

Convolutional neural network approach for enhanced capture of breast parenchymal complexity patterns associated with breast cancer risk

NASA Astrophysics Data System (ADS)

Oustimov, Andrew; Gastounioti, Aimilia; Hsieh, Meng-Kang; Pantalone, Lauren; Conant, Emily F.; Kontos, Despina

2017-03-01

We assess the feasibility of a parenchymal texture feature fusion approach, utilizing a convolutional neural network (ConvNet) architecture, to benefit breast cancer risk assessment. Hypothesizing that by capturing sparse, subtle interactions between localized motifs present in two-dimensional texture feature maps derived from mammographic images, a multitude of texture feature descriptors can be optimally reduced to five meta-features capable of serving as a basis on which a linear classifier, such as logistic regression, can efficiently assess breast cancer risk. We combine this methodology with our previously validated lattice-based strategy for parenchymal texture analysis and we evaluate the feasibility of this approach in a case-control study with 424 digital mammograms. In a randomized split-sample setting, we optimize our framework in training/validation sets (N=300) and evaluate its descriminatory performance in an independent test set (N=124). The discriminatory capacity is assessed in terms of the the area under the curve (AUC) of the receiver operator characteristic (ROC). The resulting meta-features exhibited strong classification capability in the test dataset (AUC = 0.90), outperforming conventional, non-fused, texture analysis which previously resulted in an AUC=0.85 on the same case-control dataset. Our results suggest that informative interactions between localized motifs exist and can be extracted and summarized via a fairly simple ConvNet architecture.

Geometric distortions affect face recognition in chimpanzees (Pan troglodytes) and monkeys (Macaca mulatta).

PubMed

Taubert, Jessica; Parr, Lisa A

2011-01-01

All primates can recognize faces and do so by analyzing the subtle variation that exists between faces. Through a series of three experiments, we attempted to clarify the nature of second-order information processing in nonhuman primates. Experiment one showed that both chimpanzees (Pan troglodytes) and rhesus monkeys (Macaca mulatta) tolerate geometric distortions along the vertical axis, suggesting that information about absolute position of features does not contribute to accurate face recognition. Chimpanzees differed from monkeys, however, in that they were more sensitive to distortions along the horizontal axis, suggesting that when building a global representation of facial identity, horizontal relations between features are more diagnostic of identity than vertical relations. Two further experiments were performed to determine whether the monkeys were simply less sensitive to horizontal relations compared to chimpanzees or were instead relying on local features. The results of these experiments confirm that monkeys can utilize a holistic strategy when discriminating between faces regardless of familiarity. In contrast, our data show that chimpanzees, like humans, use a combination of holistic and local features when the faces are unfamiliar, but primarily holistic information when the faces become familiar. We argue that our comparative approach to the study of face recognition reveals the impact that individual experience and social organization has on visual cognition.

Mechanism for Plasma Etching of Shallow Trench Isolation Features in an Inductively Coupled Plasma

NASA Astrophysics Data System (ADS)

Agarwal, Ankur; Rauf, Shahid; He, Jim; Choi, Jinhan; Collins, Ken

2011-10-01

Plasma etching for microelectronics fabrication is facing extreme challenges as processes are developed for advanced technological nodes. As device sizes shrink, control of shallow trench isolation (STI) features become more important in both logic and memory devices. Halogen-based inductively coupled plasmas in a pressure range of 20-60 mTorr are typically used to etch STI features. The need for improved performance and shorter development cycles are placing greater emphasis on understanding the underlying mechanisms to meet process specifications. In this work, a surface mechanism for STI etch process will be discussed that couples a fundamental plasma model to experimental etch process measurements. This model utilizes ion/neutral fluxes and energy distributions calculated using the Hybrid Plasma Equipment Model. Experiments are for blanket Si wafers in a Cl2/HBr/O2/N2 plasma over a range of pressures, bias powers, and flow rates of feedstock gases. We found that kinetic treatment of electron transport was critical to achieve good agreement with experiments. The calibrated plasma model is then coupled to a string-based feature scale model to quantify the effect of varying process parameters on the etch profile. We found that the operating parameters strongly influence critical dimensions but have only a subtle impact on the etch depths.

Quantitative Analysis of the Cervical Texture by Ultrasound and Correlation with Gestational Age.

PubMed

Baños, Núria; Perez-Moreno, Alvaro; Migliorelli, Federico; Triginer, Laura; Cobo, Teresa; Bonet-Carne, Elisenda; Gratacos, Eduard; Palacio, Montse

2017-01-01

Quantitative texture analysis has been proposed to extract robust features from the ultrasound image to detect subtle changes in the textures of the images. The aim of this study was to evaluate the feasibility of quantitative cervical texture analysis to assess cervical tissue changes throughout pregnancy. This was a cross-sectional study including singleton pregnancies between 20.0 and 41.6 weeks of gestation from women who delivered at term. Cervical length was measured, and a selected region of interest in the cervix was delineated. A model to predict gestational age based on features extracted from cervical images was developed following three steps: data splitting, feature transformation, and regression model computation. Seven hundred images, 30 per gestational week, were included for analysis. There was a strong correlation between the gestational age at which the images were obtained and the estimated gestational age by quantitative analysis of the cervical texture (R = 0.88). This study provides evidence that quantitative analysis of cervical texture can extract features from cervical ultrasound images which correlate with gestational age. Further research is needed to evaluate its applicability as a biomarker of the risk of spontaneous preterm birth, as well as its role in cervical assessment in other clinical situations in which cervical evaluation might be relevant. © 2016 S. Karger AG, Basel.

Computer-Aided Diagnostic (CAD) Scheme by Use of Contralateral Subtraction Technique

NASA Astrophysics Data System (ADS)

Nagashima, Hiroyuki; Harakawa, Tetsumi

We developed a computer-aided diagnostic (CAD) scheme for detection of subtle image findings of acute cerebral infarction in brain computed tomography (CT) by using a contralateral subtraction technique. In our computerized scheme, the lateral inclination of image was first corrected automatically by rotating and shifting. The contralateral subtraction image was then derived by subtraction of reversed image from original image. Initial candidates for acute cerebral infarctions were identified using the multiple-thresholding and image filtering techniques. As the 1st step for removing false positive candidates, fourteen image features were extracted in each of the initial candidates. Halfway candidates were detected by applying the rule-based test with these image features. At the 2nd step, five image features were extracted using the overlapping scale with halfway candidates in interest slice and upper/lower slice image. Finally, acute cerebral infarction candidates were detected by applying the rule-based test with five image features. The sensitivity in the detection for 74 training cases was 97.4% with 3.7 false positives per image. The performance of CAD scheme for 44 testing cases had an approximate result to training cases. Our CAD scheme using the contralateral subtraction technique can reveal suspected image findings of acute cerebral infarctions in CT images.

Automated analysis of free speech predicts psychosis onset in high-risk youths

PubMed Central

Bedi, Gillinder; Carrillo, Facundo; Cecchi, Guillermo A; Slezak, Diego Fernández; Sigman, Mariano; Mota, Natália B; Ribeiro, Sidarta; Javitt, Daniel C; Copelli, Mauro; Corcoran, Cheryl M

2015-01-01

Background/Objectives: Psychiatry lacks the objective clinical tests routinely used in other specializations. Novel computerized methods to characterize complex behaviors such as speech could be used to identify and predict psychiatric illness in individuals. AIMS: In this proof-of-principle study, our aim was to test automated speech analyses combined with Machine Learning to predict later psychosis onset in youths at clinical high-risk (CHR) for psychosis. Methods: Thirty-four CHR youths (11 females) had baseline interviews and were assessed quarterly for up to 2.5 years; five transitioned to psychosis. Using automated analysis, transcripts of interviews were evaluated for semantic and syntactic features predicting later psychosis onset. Speech features were fed into a convex hull classification algorithm with leave-one-subject-out cross-validation to assess their predictive value for psychosis outcome. The canonical correlation between the speech features and prodromal symptom ratings was computed. Results: Derived speech features included a Latent Semantic Analysis measure of semantic coherence and two syntactic markers of speech complexity: maximum phrase length and use of determiners (e.g., which). These speech features predicted later psychosis development with 100% accuracy, outperforming classification from clinical interviews. Speech features were significantly correlated with prodromal symptoms. Conclusions: Findings support the utility of automated speech analysis to measure subtle, clinically relevant mental state changes in emergent psychosis. Recent developments in computer science, including natural language processing, could provide the foundation for future development of objective clinical tests for psychiatry. PMID:27336038

The posterolateral corner of the knee.

PubMed

Vinson, Emily N; Major, Nancy M; Helms, Clyde A

2008-02-01

The purpose of this article is to review the clinical importance and MRI appearances of injuries to the posterolateral corner of the knee. Injuries to the posterolateral corner structures of the knee can cause significant disability due to instability, cartilage degeneration, and cruciate graft failure. Becoming familiar with the anatomy of this region can improve one's ability to detect subtle abnormalities and can perhaps lead to improvements in diagnosing and understanding injuries to this area.

Diagnosis and management of dental wear.

PubMed

Harpenau, Lisa A; Noble, Warden H; Kao, Richard T

2011-04-01

Dental wear is loss of tooth structure resulting from erosion, attrition, abrasion, and, possibly, abfraction. Clinical/experimental data suggest no single damaging mechanism but rather simultaneous interaction of these destructive processes. The most important interaction is abrasion/attrition potentiated by dental erosion. Awareness of this pathosis is not well-appreciated by the public and dental professionals because the signs may be subtle. This article focuses on the recognition, diagnosis, and management of dental wear.

Origin and hydrology of a large, intact Early Cambrian paleocave system and its role in overlying fluidisation structures, Arctic Canada

NASA Astrophysics Data System (ADS)

Mathieu, Jordan; Turner, Elizabeth C.; Rainbird, Robert H.

2017-04-01

Paleokarst is most commonly expressed as subtle stratigraphic surfaces rather than large void systems penetrating deeply into the paleo-subsurface. In contrast, a regional Precambrian-Cambrian unconformity on Victoria Island (NWT, Canada), is associated with exceptional exposure of large, intact Cambrian paleocaverns (100 m diameter; tens of m high). The paleocaves are distributed along a paleo-horizontal plane, and an associated gryke network is present in the 30-60 m of Neoproterozoic dolostone between cave rooves and the base of overlying Cambrian sandstone; both are filled by Cambrian sandstone. The formation and preservation of such karst features require aggressive dissolution along a stable paleo-water-table shortly before transgression and deposition of shallow-marine sand over the dolostone. During the transgression, the karst network acted as a conduit for flowing groundwater that was discharged through overlying, unconsolidated Cambrian shallow-marine sand, producing water-escape structures (sand volcanoes and their conduits). The conduits are preserved as cylindrical remnants of the sand volcanoes' feeder pipes. Sediment fluidisation was probably caused by variations in the hydraulic-head gradient in a meteoric lens near the Cambrian coastline under a tropical climate with abundant, probably seasonally variable rainfall that caused pulses in subsurface fluid flow. Spatial distribution of the paleocaves and sand volcanoes suggests their formation on the southeast side of a recently faulted horst of Proterozoic carbonate bedrock that formed a nearshore island during early Cambrian sea-level rise. Fluidisation structures such as those reported here have generally been difficult to interpret owing to a lack of data on the fluid hydraulics of the underlying aquifer. This is the first report linking the hydraulics of a well-characterised paleokarst to development of fluid-escape structures. Such structures are widely known from sandstones overlying the sub-Cambrian unconformity around the circumference of Laurentia.

Kwanzaa Tholus

NASA Image and Video Library

2017-12-21

These images show a subtle feature on Ceres called Kwanzaa Tholus. Kwanzaa, meaning "first fruits" in Swahili, is an African-American festival based on ancient African harvest celebrations, and takes place from December 26 to January 1. A tholus is a type of small mountain. Kwanzaa Tholus measures about 22 by 12 miles (35 by 19 kilometers) and is elevated about 2 miles (3 km) above its surroundings. Because the mountain does not rise sharply above the ground, it is difficult to see in the mosaic on the left, although a small crescent-shaped shadow stands out. The image on the right, which is an elevation map of the area, shows where Kwanzaa Tholus is more prominently. The rounded shape of Kwanzaa Tholus is typical of tholi (plural of tholus) in general, but is different than other examples found on Ceres (like Dalien Tholus) and Mars. This region is particularly rich in this type of feature: The current Ceres map shows six named tholi and montes (slightly bigger mountains) in the region (centered around 32 degrees north, 327 degrees east) and several others including Ahuna Mons farther south. Scientists say Kwanzaa Tholus may have once been as prominent as Ahuna Mons, the tallest and most noticeable mountain on Ceres. Ahuna Mons is likely a cryovolcano, a volcano formed by the gradual accumulation of thick, slowly flowing icy materials. Because ice https://www.nasa.gov/feature/goddard/2016/ceres-cryo-volcano/is not strong enough to preserve an elevated structure for extended periods, cryovolcanoes on Ceres are expected to gradually collapse over tens of millions of years. This means Kwanzaa Tholus and other tholi in that area could be degraded mountains, which also formed from cryovolcanic activity. The mosaic on the left combines images taken by NASA's Dawn spacecraft in its high-altitude mapping orbit (HAMO) at about 915 miles (1,470 kilometers) above the surface. The spatial resolution is 450 feet (140 meters) per pixel. https://photojournal.jpl.nasa.gov/catalog/PIA21916

Cerebral gray matter volume in patients with chronic migraine: correlations with clinical features.

PubMed

Coppola, Gianluca; Petolicchio, Barbara; Di Renzo, Antonio; Tinelli, Emanuele; Di Lorenzo, Cherubino; Parisi, Vincenzo; Serrao, Mariano; Calistri, Valentina; Tardioli, Stefano; Cartocci, Gaia; Ambrosini, Anna; Caramia, Francesca; Di Piero, Vittorio; Pierelli, Francesco

2017-12-08

To date, few MRI studies have been performed in patients affected by chronic migraine (CM), especially in those without medication overuse. Here, we performed magnetic resonance imaging (MRI) voxel-based morphometry (VBM) analyses to investigate the gray matter (GM) volume of the whole brain in patients affected by CM. Our aim was to investigate whether fluctuations in the GM volumes were related to the clinical features of CM. Twenty untreated patients with CM without a past medical history of medication overuse underwent 3-Tesla MRI scans and were compared to a group of 20 healthy controls (HCs). We used SPM12 and the CAT12 toolbox to process the MRI data and to perform VBM analyses of the structural T1-weighted MRI scans. The GM volume of patients was compared to that of HCs with various corrected and uncorrected thresholds. To check for possible correlations, patients' clinical features and GM maps were regressed. Initially, we did not find significant differences in the GM volume between patients with CM and HCs (p < 0.05 corrected for multiple comparisons). However, using more-liberal uncorrected statistical thresholds, we noted that compared to HCs, patients with CM exhibited clusters of regions with lower GM volumes including the cerebellum, left middle temporal gyrus, left temporal pole/amygdala/hippocampus/pallidum/orbitofrontal cortex, and left occipital areas (Brodmann areas 17/18). The GM volume of the cerebellar hemispheres was negatively correlated with the disease duration and positively correlated with the number of tablets taken per month. No gross morphometric changes were observed in patients with CM when compared with HCs. However, using more-liberal uncorrected statistical thresholds, we observed that CM is associated with subtle GM volume changes in several brain areas known to be involved in nociception/antinociception, multisensory integration, and analgesic dependence. We speculate that these slight morphometric impairments could lead, at least in a subgroup of patients, to the development and continuation of maladaptive acute medication usage.

Rock formation characterization for carbon dioxide geosequestration: 3D seismic amplitude and coherency anomalies, and seismic petrophysical facies classification, Wellington and Anson-Bates Fields, Kansas, USA

NASA Astrophysics Data System (ADS)

Ohl, Derek; Raef, Abdelmoneam

2014-04-01

Higher resolution rock formation characterization is of paramount priority, amid growing interest in injecting carbon dioxide, CO2, into subsurface rock formations of depeleting/depleted hydrocarbon reservoirs or saline aquifers in order to reduce emissions of greenhouse gases. In this paper, we present a case study for a Mississippian carbonate characterization integrating post-stack seismic attributes, well log porosities, and seismic petrophysical facies classification. We evaluated changes in petrophysical lithofacies and reveal structural facies-controls in the study area. Three cross-plot clusters in a plot of well log porosity and acoustic impedance corroborated a Neural Network petrophysical facies classification, which was based on training and validation utilizing three petrophysically-different wells and three volume seismic attributes, extracted from a time window including the wavelet of the reservoir-top reflection. Reworked lithofacies along small-throw faults has been revealed based on comparing coherency and seismic petrophysical facies. The main objective of this study is to put an emphasis on reservoir characterization that is both optimized for and subsequently benefiting from pilot tertiary CO2 carbon geosequestration in a depleting reservoir and also in the deeper saline aquifer of the Arbuckle Group, south central Kansas. The 3D seismic coherency attribute, we calculated from a window embracing the Mississippian top reflection event, indicated anomalous features that can be interpreted as a change in lithofacies or faulting effect. An Artificial Neural Network (ANN) lithofacies modeling has been used to better understand these subtle features, and also provide petrophysical classes, which will benefit flow-simulation modeling and/or time-lapse seismic monitoring feasibility analysis. This paper emphasizes the need of paying greater attention to small-scale features when embarking upon characterization of a reservoir or saline-aquifer for CO2 based carbon geosequestration.

Detecting Precontact Anthropogenic Microtopographic Features in a Forested Landscape with Lidar: A Case Study from the Upper Great Lakes Region, AD 1000-1600

PubMed Central

Howey, Meghan C. L.; Sullivan, Franklin B.; Tallant, Jason; Kopple, Robert Vande; Palace, Michael W.

2016-01-01

Forested settings present challenges for understanding the full extent of past human landscape modifications. Field-based archaeological reconnaissance in forests is low-efficiency and most remote sensing techniques are of limited utility, and together, this means many past sites and features in forests are unknown. Archaeologists have increasingly used light detection and ranging (lidar), a remote sensing tool that uses pulses of light to measure reflecting surfaces at high spatial resolution, to address these limitations. Archaeology studies using lidar have made significant progress identifying permanent structures built by large-scale complex agriculturalist societies. Largely unaccounted for, however, are numerous small and more practical modifications of landscapes by smaller-scale societies. Here we show these may also be detectable with lidar by identifying remnants of food storage pits (cache pits) created by mobile hunter-gatherers in the upper Great Lakes during Late Precontact (ca. AD 1000–1600) that now only exist as subtle microtopographic features. Years of intensive field survey identified 69 cache pit groups between two inland lakes in northern Michigan, almost all of which were located within ~500 m of a lakeshore. Applying a novel series of image processing techniques and statistical analyses to a high spatial resolution DTM we created from commercial-grade lidar, our detection routine identified 139 high potential cache pit clusters. These included most of the previously known clusters as well as several unknown clusters located >1500 m from either lakeshore, much further from lakeshores than all previously identified cultural sites. Food storage is understood to have emerged regionally as a risk-buffering strategy after AD 1000 but our results indicate the current record of hunter-gatherer cache pit food storage is markedly incomplete and this practice and its associated impact on the landscape may be greater than anticipated. Our study also demonstrates the potential of harnessing commercial-grade lidar for other fine-grained archaeology applications. PMID:27584031

Detecting Precontact Anthropogenic Microtopographic Features in a Forested Landscape with Lidar: A Case Study from the Upper Great Lakes Region, AD 1000-1600.

PubMed

Howey, Meghan C L; Sullivan, Franklin B; Tallant, Jason; Kopple, Robert Vande; Palace, Michael W

2016-01-01

Forested settings present challenges for understanding the full extent of past human landscape modifications. Field-based archaeological reconnaissance in forests is low-efficiency and most remote sensing techniques are of limited utility, and together, this means many past sites and features in forests are unknown. Archaeologists have increasingly used light detection and ranging (lidar), a remote sensing tool that uses pulses of light to measure reflecting surfaces at high spatial resolution, to address these limitations. Archaeology studies using lidar have made significant progress identifying permanent structures built by large-scale complex agriculturalist societies. Largely unaccounted for, however, are numerous small and more practical modifications of landscapes by smaller-scale societies. Here we show these may also be detectable with lidar by identifying remnants of food storage pits (cache pits) created by mobile hunter-gatherers in the upper Great Lakes during Late Precontact (ca. AD 1000-1600) that now only exist as subtle microtopographic features. Years of intensive field survey identified 69 cache pit groups between two inland lakes in northern Michigan, almost all of which were located within ~500 m of a lakeshore. Applying a novel series of image processing techniques and statistical analyses to a high spatial resolution DTM we created from commercial-grade lidar, our detection routine identified 139 high potential cache pit clusters. These included most of the previously known clusters as well as several unknown clusters located >1500 m from either lakeshore, much further from lakeshores than all previously identified cultural sites. Food storage is understood to have emerged regionally as a risk-buffering strategy after AD 1000 but our results indicate the current record of hunter-gatherer cache pit food storage is markedly incomplete and this practice and its associated impact on the landscape may be greater than anticipated. Our study also demonstrates the potential of harnessing commercial-grade lidar for other fine-grained archaeology applications.

Neuromotor outcomes at school age after extremely low birth weight: early detection of subtle signs.

PubMed

Gidley Larson, Jennifer C; Baron, Ida Sue; Erickson, Kristine; Ahronovich, Margot D; Baker, Robin; Litman, Fern R

2011-01-01

Motor impairments are prevalent in children born at extremely low birth weight (ELBW; <1,000 g). Rarely studied are subtle motor deficits that indicate dysfunction or delay in neural systems critical for optimal cognitive, academic, and behavioral function. We aimed to examine quantifiable signs of subtle neuromotor dysfunction in an early school-aged ELBW cohort that coincidentally had age-appropriate cognition and design copying. We studied 97 participants born between 1998 and 2001; 74 ELBW (6.7 years ± 0.75) compared with 23 term-born (6.6 years ± 0.29). Neuromotor outcomes were assessed using the Physical and Neurological Examination of Subtle Signs-Revised, and measures of dexterity/coordination and visual-motor integration. ELBW participants performed worse than term-born on design-copying and dexterity, were age-appropriate compared to normative data, and had slower timed movements and more subtle overflow movements. Those ELBW born <26 weeks performed most poorly compared with those born 26-34 weeks and term-born. Subtle motor dysfunctions are detectable and quantifiable in ELBW children by school age, even in the presence of average cognition. Early age assessment of incoordination, motor speed, and overflow movements should aid initiation of timely therapies to prepare at-risk ELBW children for subsequent school entry and facilitate design of optimal early treatment strategies. (c) 2010 APA, all rights reserved.

Visualization of Hyperconjugation and Subsequent Structural Distortions through 3D Printing of Crystal Structures.

PubMed

Mithila, Farha J; Oyola-Reynoso, Stephanie; Thuo, Martin M; Atkinson, Manza Bj

2016-01-01

Structural distortions due to hyperconjugation in organic molecules, like norbornenes, are well captured through X-ray crystallographic data, but are sometimes difficult to visualize especially for those applying chemical knowledge and are not chemists. Crystal structure from the Cambridge database were downloaded and converted to .stl format. The structures were then printed at the desired scale using a 3D printer. Replicas of the crystal structures were accurately reproduced in scale and any resulting distortions were clearly visible from the macroscale models. Through space interactions or effect of through space hyperconjugation was illustrated through loss of symmetry or distortions thereof. The norbornene structures exhibits distortion that cannot be observed through conventional ball and stick modelling kits. We show that 3D printed models derived from crystallographic data capture even subtle distortions in molecules. We translate such crystallographic data into scaled-up models through 3D printing.

Density Waves in Saturn's Rings from Cassini Radio Occultations

NASA Astrophysics Data System (ADS)

French, R. G.; Rappaport, N. J.; Marouf, E. A.; McGhee, C. A.

2005-12-01

The Cassini Radio Science Team conducted a set of optimized diametric occultations by Saturn and its rings from May to September 2005, providing 11 separate probes of Saturn's ionosphere and atmosphere, and 12 optical depth profiles of the complete ring system. Each event was observed by the stations of the Deep Space Net (DSN) at three radio frequencies (S, X, Ka bands, with corresponding wavelengths of ? = 13, 3.6, and 0.9 cm). Very accurate pointing by the spacecraft and ground antennas resulted in stable baseline signal levels, and the relatively large ring opening angle (B=19-25°) permitted us to probe even quite dense ring regions with excellent SNR. The RSS occultation technique enables us to recover very fine detailed radial structure by correcting for diffraction effects. Multiple occultation chords, covering a variety of ring longitudes and ring opening angles, reveal the structure of the rings in remarkable detail, including density and bending waves, satellite wakes, and subtle variations at the 100-m radius scale. Janus and Epimetheus are responsible for a particularly rich set of density waves, and their coorbital interactions result in a complex interplay of time-variable ring structure over the 8-year libration period of the two satellites. We compare the first-order 2:1, 4:3, 5:4, and 6:5 coorbital density waves from multiple occultation chords to linear density wave models based on a dynamical model of the orbital exchange between the moons. From the observed dispersion relation of the wave crests, we infer the surface mass density and eccentricity gradient of particle streamlines, and match the detailed shapes of the wave crests using a non-linear analysis. Second-order coorbital features are also evident, and there are even hints of third-order density waves in the high SNR radio occultation data.

Structure-function correlation of chloroquine and analogues as transgene expression enhancers in nonviral gene delivery.

PubMed

Cheng, Jianjun; Zeidan, Ryan; Mishra, Swaroop; Liu, Aijie; Pun, Suzie H; Kulkarni, Rajan P; Jensen, Gregory S; Bellocq, Nathalie C; Davis, Mark E

2006-11-02

To understand how chloroquine (CQ) enhances transgene expression in polycation-based, nonviral gene delivery systems, a number of CQ analogues with variations in the aliphatic amino side chain or in the aromatic ring are synthesized and investigated. Our studies indicate that the aliphatic amino moiety of CQ is essential to provide increased gene expression. Further, the enhancements are more dramatically affected by changes to the aromatic ring and are positively correlated to the strength of intercalation between DNA and the CQ analogues. Quinacrine (QC), a CQ analogue with a fused acridinyl structure that can strongly intercalate DNA, enhances transfection similarly to CQ at a concentration 10 times lower, while N(4)-(4-pyridinyl)-N(1),N(1)-diethyl-1,4-pentanediamine (CP), a CQ analogue that has a weakly intercalating pyridinyl ring, shows no effect on gene expression. Subtle change on the 7-substituent of the chloroquine aromatic structure can also greatly affect the ability of the CQ analogues to enhance transgene expression. Transfection in the presence of N(4)-(7-trifluoromethyl-4-quinolinyl)-N(1),N(1)-diethyl-1,4-pentanediamin e (CQ7a) shows expression efficiency 10 times higher than in the presence of CQ at same concentration, while transfection in the presence of N(4)-(4-quinolinyl)-N(1),N(1)-diethyl-1,4-pentanediamine (CQ7b) does not reveal any enhancing effects on expression. Through a number of comparative studies with CQ and its analogues, we conclude that there are at least three mechanistic features of CQ that lead to the enhancement in gene expression: (i) pH buffering in endocytic vesicles, (ii) displacement of polycations from the nucleic acids in polyplexes, and (iii) alteration of the biophysical properties of the released nucleic acid.

Ligand and coactivator identity determines the requirement of the charge clamp for coactivation of the peroxisome proliferator-activated receptor gamma.

PubMed

Wu, Yifei; Chin, William W; Wang, Yong; Burris, Thomas P

2003-03-07

The activation function 2 (AF-2)-dependent recruitment of coactivator is essential for gene activation by nuclear receptors. We show that the peroxisome proliferator-activated receptor gamma (PPARgamma) (NR1C3) coactivator-1 (PGC-1) requires both the intact AF-2 domain of PPARgamma and the LXXLL domain of PGC-1 for ligand-dependent and ligand-independent interaction and coactivation. Although the AF-2 domain of PPARgamma is absolutely required for PGC-1-mediated coactivation, this coactivator displayed a unique lack of requirement for the charge clamp of the ligand-binding domain of the receptor that is thought to be essential for LXXLL motif recognition. The mutation of a single serine residue adjacent to the core LXXLL motif of PGC-1 led to restoration of the typical charge clamp requirement. Thus, the unique structural features of the PGC-1 LXXLL motif appear to mediate an atypical mode of interaction with PPARgamma. Unexpectedly, we discovered that various ligands display variability in terms of their requirement for the charge clamp of PPARgamma for coactivation by PGC-1. This ligand-selective variable requirement for the charge clamp was coactivator-specific. Thus, distinct structural determinants, which may be unique for a particular ligand, are utilized by the receptor to recognize the coactivator. Our data suggest that even subtle differences in ligand structure are perceived by the receptor and translated into a unique display of the coactivator-binding surface of the ligand-binding domain, allowing for differential recognition of coactivators that may underlie distinct pharmacological profiles observed for ligands of a particular nuclear receptor.

Atypical behavior in the electron capture induced dissociation of biologically relevant transition metal ion complexes of the peptide hormone oxytocin

NASA Astrophysics Data System (ADS)

Kleinnijenhuis, Anne J.; Mihalca, Romulus; Heeren, Ron M. A.; Heck, Albert J. R.

2006-07-01

Doubly protonated ions of the disulfide bond containing nonapeptide hormone oxytocin and oxytocin complexes with different transition metal ions, that have biological relevance under physiological conditions, were subjected to electron capture dissociation (ECD) to probe their structural features in the gas phase. Although, all the ECD spectra were strikingly different, typical ECD behavior was observed for complexes of the nonapeptide hormone oxytocin with Ni2+, Co2+ and Zn2+, i.e., abundant c/z' and a'/y backbone cleavages and ECD characteristic S-S and S-C bond cleavages were observed. We propose that, although in the oxytocin-transition metal ion complexes the metal ions serve as the main initial capture site, the captured electron is transferred to other sites in the complex to form a hydrogen radical, which drives the subsequent typical ECD fragmentations. The complex of oxytocin with Cu2+ displayed noticeably different ECD behavior. The fragment ions were similar to fragment ions typically observed with low-energy collision induced dissociation (CID). We propose that the electrons captured by the oxytocin-Cu2+ complex might be favorably involved in reducing the Cu2+ metal ion to Cu+. Subsequent energy redistribution would explain the observed low-energy CID-type fragmentations. Electron capture resulted also in quite different specific cleavage sites for the complexes of oxytocin with Ni2+, Co2+ and Zn2+. This is an indication for structural differences in these complexes possibly linked to their significantly different biological effects on oxytocin-receptor binding, and suggests that ECD may be used to study subtle structural differences in transition metal ion-peptide complexes.

Modulation of structural, electrical, and magnetic features with dilute Zr substitution in Bi0.8La0.2Fe1-xZrxO3 system

NASA Astrophysics Data System (ADS)

Usama, Hasan M.; Akter, Ayesha; Zubair, M. A.

2017-12-01

A significant structural modification and enhancement of the electrical and magnetic properties with dilute substitution of Zr (≤1 mol. %) in the Bi0.8La0.2Fe1-xZrxO3 system has been reported. A mixture of rhombohedral and orthorhombic phases was detected in these conventionally sintered ceramics. Transition from a leaky state to an insulating state was observed upon Zr substitution. This is the first time that a drop in the electrical conductivity as large as 6 orders of magnitude for doping as small as 0.25 mol. % in bismuth ferrite systems has been reported. An investigation on the nature of this abrupt transition revealed the dominant role of defects. A proper consideration of possible defect reactions taking place during and after sintering satisfactorily accounts for the observed modulation in the electrical properties. Both AC and DC measurements indicate that, before Zr substitution, p-type hopping conduction prevails with an activation energy as low as ˜0.57 eV, whereas the Zr substitution makes oxide ion migration the central mechanism for conduction with the activation energy of ˜0.96-1.08 eV. In contrast to that, the magnetic properties of the compounds experience a more subtle effect; a gradual modification of saturation magnetization and coercivity with Zr substitution is observed. Curve fitting of the magnetic hysteresis loops not only allowed extraction of three separate contributions from the magnetic response but also helped to explain the effects of Zr on the magnetic properties. Modifications of structural characteristics and magnetic anisotropy of the samples are believed to be the primary driving force behind the improvement in the magnetic properties.

Nucleus Accumbens Invulnerability to Methamphetamine Neurotoxicity

PubMed Central

Kuhn, Donald M.; Angoa-Pérez, Mariana; Thomas, David M.

2016-01-01

Methamphetamine (Meth) is a neurotoxic drug of abuse that damages neurons and nerve endings throughout the central nervous system. Emerging studies of human Meth addicts using both postmortem analyses of brain tissue and noninvasive imaging studies of intact brains have confirmed that Meth causes persistent structural abnormalities. Animal and human studies have also defined a number of significant functional problems and comorbid psychiatric disorders associated with long-term Meth abuse. This review summarizes the salient features of Meth-induced neurotoxicity with a focus on the dopamine (DA) neuronal system. DA nerve endings in the caudate-putamen (CPu) are damaged by Meth in a highly delimited manner. Even within the CPu, damage is remarkably heterogeneous, with ventral and lateral aspects showing the greatest deficits. The nucleus accumbens (NAc) is largely spared the damage that accompanies binge Meth intoxication, but relatively subtle changes in the disposition of DA in its nerve endings can lead to dramatic increases in Meth-induced toxicity in the CPu and overcome the normal resistance of the NAc to damage. In contrast to the CPu, where DA neuronal deficiencies are persistent, alterations in the NAc show a partial recovery. Animal models have been indispensable in studies of the causes and consequences of Meth neurotoxicity and in the development of new therapies. This research has shown that increases in cytoplasmic DA dramatically broaden the neurotoxic profile of Meth to include brain structures not normally targeted for damage. The resistance of the NAc to Meth-induced neurotoxicity and its ability to recover reveal a fundamentally different neuroplasticity by comparison to the CPu. Recruitment of the NAc as a target of Meth neurotoxicity by alterations in DA homeostasis is significant in light of the numerous important roles played by this brain structure. PMID:23382149

Nucleus accumbens invulnerability to methamphetamine neurotoxicity.

PubMed

Kuhn, Donald M; Angoa-Pérez, Mariana; Thomas, David M

2011-01-01

Methamphetamine (Meth) is a neurotoxic drug of abuse that damages neurons and nerve endings throughout the central nervous system. Emerging studies of human Meth addicts using both postmortem analyses of brain tissue and noninvasive imaging studies of intact brains have confirmed that Meth causes persistent structural abnormalities. Animal and human studies have also defined a number of significant functional problems and comorbid psychiatric disorders associated with long-term Meth abuse. This review summarizes the salient features of Meth-induced neurotoxicity with a focus on the dopamine (DA) neuronal system. DA nerve endings in the caudate-putamen (CPu) are damaged by Meth in a highly delimited manner. Even within the CPu, damage is remarkably heterogeneous, with ventral and lateral aspects showing the greatest deficits. The nucleus accumbens (NAc) is largely spared the damage that accompanies binge Meth intoxication, but relatively subtle changes in the disposition of DA in its nerve endings can lead to dramatic increases in Meth-induced toxicity in the CPu and overcome the normal resistance of the NAc to damage. In contrast to the CPu, where DA neuronal deficiencies are persistent, alterations in the NAc show a partial recovery. Animal models have been indispensable in studies of the causes and consequences of Meth neurotoxicity and in the development of new therapies. This research has shown that increases in cytoplasmic DA dramatically broaden the neurotoxic profile of Meth to include brain structures not normally targeted for damage. The resistance of the NAc to Meth-induced neurotoxicity and its ability to recover reveal a fundamentally different neuroplasticity by comparison to the CPu. Recruitment of the NAc as a target of Meth neurotoxicity by alterations in DA homeostasis is significant in light of the numerous important roles played by this brain structure.

Structural MRI biomarkers of shared pathogenesis in autism spectrum disorder and epilepsy.

PubMed

Blackmon, Karen

2015-06-01

Etiological factors that contribute to a high comorbidity between autism spectrum disorder (ASD) and epilepsy are the subject of much debate. Does epilepsy cause ASD or are there common underlying brain abnormalities that increase the risk of developing both disorders? This review summarizes evidence from quantitative MRI studies to suggest that abnormalities of brain structure are not necessarily the consequence of ASD and epilepsy but are antecedent to disease expression. Abnormal gray and white matter volumes are present prior to onset of ASD and evident at the time of onset in pediatric epilepsy. Aberrant brain growth trajectories are also common in both disorders, as evidenced by blunted gray matter maturation and white matter maturation. Although the etiological factors that explain these abnormalities are unclear, high heritability estimates for gray matter volume and white matter microstructure demonstrate that genetic factors assert a strong influence on brain structure. In addition, histopathological studies of ASD and epilepsy brain tissue reveal elevated rates of malformations of cortical development (MCDs), such as focal cortical dysplasia and heterotopias, which supports disruption of neuronal migration as a contributing factor. Although MCDs are not always visible on MRI with conventional radiological analysis, quantitative MRI detection methods show high sensitivity to subtle malformations in epilepsy and can be potentially applied to MCD detection in ASD. Such an approach is critical for establishing quantitative neuroanatomic endophenotypes that can be used in genetic research. In the context of emerging drug treatments for seizures and autism symptoms, such as rapamycin and rapalogs, in vivo neuroimaging markers of subtle structural brain abnormalities could improve sample stratification in human clinical trials and potentially extend the range of patients that might benefit from treatment. This article is part of a Special Issue entitled "Autism and Epilepsy". Copyright © 2015 Elsevier Inc. All rights reserved.

Spaceborne Potential for Examining Taiga-Tundra Ecotone Form and Vulnerability

NASA Technical Reports Server (NTRS)

Montesano, Paul M.; Sun, Guoqing; Dubayah, Ralph O.; Ranson, K. Jon

2016-01-01

In the taiga-tundra ecotone (TTE), site-dependent forest structure characteristics can influence the subtle and heterogeneous structural changes that occur across the broad circumpolar extent. Such changes may be related to ecotone form, described by the horizontal and vertical patterns of forest structure (e.g., tree cover, density and height) within TTE forest patches, driven by local site conditions, and linked to ecotone dynamics. The unique circumstance of subtle, variable and widespread vegetation change warrants the application of spaceborne data including high-resolution (less than 5m) spaceborne imagery (HRSI) across broad scales for examining TTE form and predicting dynamics. This study analyzes forest structure at the patch-scale in the TTE to provide a means to examine both vertical and horizontal components of ecotone form. We demonstrate the potential of spaceborne data for integrating forest height and density to assess TTE form at the scale of forest patches across the circumpolar biome by (1) mapping forest patches in study sites along the TTE in northern Siberia with a multi-resolution suite of spaceborne data, and (2) examining the uncertainty of forest patch height from this suite of data across sites of primarily diffuse TTE forms. Results demonstrate the opportunities for improving patch-scale spaceborne estimates of forest height, the vertical component of TTE form, with HRSI. The distribution of relative maximum height uncertainty based on prediction intervals is centered at approximately 40%, constraining the use of height for discerning differences in forest patches. We discuss this uncertainty in light of a conceptual model of general ecotone forms, and highlight how the uncertainty of spaceborne estimates of height can contribute to the uncertainty in identifying TTE forms. A focus on reducing the uncertainty of height estimates in forest patches may improve depiction of TTE form, which may help explain variable forest responses in the TTE to climate change and the vulnerability of portions of the TTE to forest structure change. structural changes.

Cardiac structure and function across the glycemic spectrum in elderly men and women free of prevalent heart disease: the Atherosclerosis Risk In the Community study.

PubMed

Skali, Hicham; Shah, Amil; Gupta, Deepak K; Cheng, Susan; Claggett, Brian; Liu, Jiankang; Bello, Natalie; Aguilar, David; Vardeny, Orly; Matsushita, Kunihiro; Selvin, Elizabeth; Solomon, Scott

2015-05-01

Individuals with diabetes mellitus and pre-diabetes mellitus are at particularly high risk of incident heart failure or death, even after accounting for known confounders. Nevertheless, the extent of impairments in cardiac structure and function in elderly individuals with diabetes mellitus and pre-diabetes mellitus is not well known. We aimed to assess the relationship between echocardiographic measures of cardiac structure and function and dysglycemia. We assessed measures of cardiac structure and function in 4419 participants without prevalent coronary heart disease or heart failure who attended the Atherosclerosis Risk In the Community (ARIC) visit 5 examination (2011-2013) and underwent transthoracic echocardiography (age, 75±6 years; 61% women, 23% black). Subjects were grouped across the dysglycemia spectrum as normal (39%), pre-diabetes mellitus (31%), or diabetes mellitus (30%) based on medical history, antidiabetic medication use, and glycated hemoglobin levels. Glycemic status was related to measures of cardiac structure and function. Worsening dysglycemia was associated with increased left ventricular mass, worse diastolic function, and subtle reduction in left ventricular systolic function (P≤0.01 for all). For every 1% higher glycated hemoglobin, left ventricular mass was higher by 3.0 g (95% confidence interval, 1.5-4.6 g), E/E' by 0.5 (95% confidence interval, 0.4-0.7), and global longitudinal strain by 0.3% (95% confidence interval, 0.2-0.4) in multivariable analyses. In a large contemporary biracial cohort of elderly subjects without prevalent cardiovascular disease or heart failure, dysglycemia was associated with subtle and subclinical alterations of cardiac structure, and left ventricular systolic and diastolic function. It remains unclear whether these are sufficient to explain the heightened risk of heart failure in individuals with diabetes mellitus. © 2015 American Heart Association, Inc.

Dysmorphic features and developmental outcome of 2-year-old children.

PubMed

Seggers, Jorien; Haadsma, Maaike L; Bos, Arend F; Heineman, Maas Jan; Middelburg, Karin J; van den Heuvel, Edwin R; Hadders-Algra, Mijna

2014-11-01

The aim of this study was to assess the associations between dysmorphic features and neurological, mental, psychomotor, and behavioural development in order to improve our understanding of aetiological pathways leading to minor developmental problems. In our cross-sectional study, 272 generally healthy 2-year-olds (143 males, 129 females; median gestational age 39 weeks, [range 30-43wks]), born after a parental history of subfertility either with or without fertility treatment, were examined. Dysmorphic features were classified as abnormalities (clinically relevant or not), minor anomalies, or common variants according to Merks' classification system. Hempel's neurological assessment resulted in a neurological optimality score (NOS) and fluency score. Mental and psychomotor development were assessed with the Dutch version of the Bayley Scales of Infant Development and behavioural development with the Achenbach Child Behaviour Checklist. Of the different types of dysmorphic feature, clinically relevant abnormalities were most strongly associated with a lower NOS (difference -2.53, 95% confidence interval [CI] -4.23 to -0.83) and fluency score (difference -0.62, 95% CI -1.1 to -0.15). The presence of one or more abnormalities (clinically relevant or not) or one or more common variants was significantly associated with a lower NOS, and the presence of three or more minor anomalies was associated with lower fluency scores. Dysmorphic features were not associated with mental, psychomotor, or behavioural development. As dysmorphic features originate during the first trimester of pregnancy, the association between dysmorphic features and minor alterations in neurodevelopment may suggest an early ontogenetic origin of subtle neurological deviations. © 2014 Mac Keith Press.

Three Fresh Exposures, Enhanced Color

NASA Technical Reports Server (NTRS)

2004-01-01

This enhanced-color panoramic camera image from the Mars Exploration Rover Opportunity features three holes created by the rock abrasion tool between sols 143 and 148 (June 18 and June 23, 2004) inside 'Endurance Crater.' The enhanced image makes the red colors a little redder and blue colors a little bluer, allowing viewers to see differences too subtle to be seen without the exaggeration. When compared with an approximately true color image, the tailings from the rock abrasion tool and the interior of the abraded holes are more prominent in this view. Being able to discriminate color variations helps scientists determine rocks' compositional differences and texture variations. This image was created using the 753-, 535- and 432-nanometer filters.

Applying Behavioral Economics to Public Health Policy

PubMed Central

Matjasko, Jennifer L.; Cawley, John H.; Baker-Goering, Madeleine M.; Yokum, David V.

2016-01-01

Behavioral economics provides an empirically informed perspective on how individuals make decisions, including the important realization that even subtle features of the environment can have meaningful impacts on behavior. This commentary provides examples from the literature and recent government initiatives that incorporate concepts from behavioral economics in order to improve health, decision making, and government efficiency. The examples highlight the potential for behavioral economics to improve the effectiveness of public health policy at low cost. Although incorporating insights from behavioral economics into public health policy has the potential to improve population health, its integration into government public health programs and policies requires careful design and continual evaluation of such interventions. Limitations and drawbacks of the approach are discussed. PMID:27102853

1−1=Counterfactual: on the potency and significance of quantum non-events

PubMed Central

Cohen, E.

2016-01-01

We study the unique role played in quantum mechanics by non-events or ‘counterfactuals’. Our earlier analysis of ‘quantum oblivion’ has revealed some subtle stages in the measurement process, which may end up in self-cancellation. To these findings, we now add two insights derived by two time-symmetric interpretations of quantum mechanics. (i) Like all quantum interactions, the non-event is formed by the conjunction of forward-plus-backward-evolving wave functions. (ii) Then, it is another feature of such dual evolutions, namely the involvement of negative masses and energies, that enables Nature to make some events ‘unhappen’ while leaving causal traces. PMID:27091159

1-1=Counterfactual: on the potency and significance of quantum non-events.

PubMed

Elitzur, A C; Cohen, E

2016-05-28

We study the unique role played in quantum mechanics by non-events or 'counterfactuals'. Our earlier analysis of 'quantum oblivion' has revealed some subtle stages in the measurement process, which may end up in self-cancellation. To these findings, we now add two insights derived by two time-symmetric interpretations of quantum mechanics. (i) Like all quantum interactions, the non-event is formed by the conjunction of forward-plus-backward-evolving wave functions. (ii) Then, it is another feature of such dual evolutions, namely the involvement of negative masses and energies, that enables Nature to make some events 'unhappen' while leaving causal traces. © 2016 The Author(s).

Complementary angiographic and autofluorescence findings in pseudoxanthoma elasticum.

PubMed

Lee, Thomas K M; Forooghian, Farzin; Cukras, Catherine; Wong, Wai T; Chew, Emily Y; Meyerle, Catherine B

2010-02-01

Pseudoxanthoma elasticum (PXE) is a systemic disease with characteristic findings on fundus examination. The fundus findings may be difficult to detect with ophthalmoscopy. A case report is described as follows. A PXE patient had subtle retinal findings on fundoscopy that were more prominently seen using a combination of both fundus autofluorescence (FAF) imaging and indocyanine green (ICG) angiography. The fundus features visualized using each of these two modalities appeared different from each other. FAF imaging and ICG angiography may be able to more prominently detect pathology at the level of the retinal pigment epithelium and Bruch's membrane, respectively. The use of these imaging modalities together may be complementary and useful in the evaluation of patients with PXE.

Imaging and Screening of Cancer of the Small Bowel.

PubMed

Kim, Jin Sil; Park, Seong Ho; Hansel, Stephanie; Fletcher, Joel G

2017-11-01

Delayed diagnosis of small bowel cancers frequently occurs and may arise because of many factors, including low incidence of disease, difficult endoscopic access, lack of mucosal mass or abnormality, subtle radiologic features, and low index of clinical suspicion. As small bowel cancers are rare and their causes are largely unknown, routine population-based screening of asymptomatic patients to find precursor lesions or early cancers is ineffective. However, targeted screening/surveillance strategies are used in specific at-risk and symptomatic patient populations. This article reviews issues regarding early diagnosis of small bowel cancers, with focus on state-of-the-art cross-sectional imaging techniques. Copyright © 2017 Elsevier Inc. All rights reserved.

NGH: A Dynamic Factor in Deep Water Sediments & the Geological Record

NASA Astrophysics Data System (ADS)

Max, M. D.; Johnson, A. H.

2012-12-01

Prior to identification of natural gas hydrate (NGH) in marine sediments, gravity and tectonic forces were the recognized dynamic forces that could cause disruption in deep marine sediments. NGH introduces a new dynamic factor into continental slope and rise sediments as well as sediments in the deeper parts of some continental shelves. Two critical elements interplay to provide for a slow acting, long-term NGH-dynamic cyclical system. First, NGH forms spontaneously from dissolved natural gas generally in a passive manner without causing any other than very subtle alterations to the megascopic sediment structure. When NGH forms in either dispersed form in muddy sediments or in concentrated form in veins or nodules or in porosity in sandy sediments, it increases overall mechanical strength. Second, when it dissociates, mechanical strength weakens to the point where shear strengths can approach zero. Because the chemical reaction of NGH is highly reversible, changes in sea level that affect pressure, and changes in seafloor temperature can alter rapidly the tendency of NGH to either crystallize or dissociate, with consequent structural and morphological effects. The cyclicity of the Earth's climate introduces a mechanism for periodically injecting overpressured gas into marine sediments as the gas hydrate stability zones (GHSZ) undergoes changes to its thickness and depth. Natural climate change has the potential to produce overpressured natural gas converted from NGH in marine sediments periodically. In-place disruption would consist of disrupted sandy beds, chaotic textures on all scales, intrusion effects, limited mass flow features, dramatic sediment mixing not related to large scale movement and sediment redeposition from fluidized beds. Mobilization would involve larger scale sediment mass flow effects that would be indistinguishable from olistostromic melanges postulated to be initiated by tectonic or gravitational forces. The earliest interpretation of this fluidization type of large scale sediment disruption in the later part of the 1900s identified them as tectonic in origin. Subsequently, in the 1970s, it was recognized that the features were more likely a product of soft sediment deformation whose initiator might be gravity or tectonic forces, of 'tectonosedimentary' origin. The action of the NGH cycle to initiate sedimentary disruption may more readily explain many of these features in the geological record. Drill core taken across seismic reflection sediment redeposition features that otherwise show no tectonic activity related movement in abandoned GHSZ could provide important evidence for the long-term geological action of the NGH cycle.

Magnetic, gravity, radiometric, LiDAR, and seismic data to characterize the region of the M5.8 August 23, 2011 earthquake near Mineral, Virginia

NASA Astrophysics Data System (ADS)

Shah, A. K.; McNamara, D. E.; Odum, J. K.; Stephenson, W. J.; Kayen, R. E.; Emmett, P. F.; Herrmann, R. B.; Snyder, S. L.; Horton, J. W.; Williams, R. A.

2012-12-01

In response to the M5.8 August 23, 2011 Mineral, VA earthquake, the U.S. Geological Survey and partner organizations acquired or sponsored collection of several geophysical datasets to assist characterization of the earthquake region. Goals include the mapping of the main shock causative and aftershock faults as well as associated geologic features which may be buried or difficult to access, estimates of regional ground motion attenuation, and measurements describing local amplification of seismic energy. The deployment of 46 portable seismic stations by several organizations within days following the earthquake, along with public availability of the resulting data, has greatly aided site characterization efforts. The aftershock data recorded by these stations have allowed delineation of the probable causative fault and other faults that were active afterwards. Using the portable seismograph network and regional permanent stations, S and Lg waves were analyzed to estimate crustal attenuation characteristics. Active- and passive-source seismic experiments were also conducted at many of the portable and permanent stations to characterize site conditions and constrain local response models via estimates of Vs30 and bedrock depth. In March 2012, a LiDAR survey with 8pt/m2 resolution was flown over a ~20x35 km area covering the epicenters of the earthquake and most aftershocks. In July 2012, a high-resolution airborne magnetic, gravity, and radiometric survey was flown over a similar but slightly smaller area. Supplementary ground gravity data have been collected inside and outside of the airborne survey areas. The gravity and magnetic data reflect subsurface features in a region where outcropping rocks are sparse, while LiDAR and radiometric data, respectively, delineate subtle features at the land surface and upper few centimeters. Each of these datasets reflects the regional NE-SW striking fabric. Seismic wave analyses show preferential attenuation in a NW-SE direction, perpendicular to major structures and consistent with estimates of motion intensity such as USGS "Did you feel it?" website responses and local damage reports (Virginia DMME). Preliminary analyses of strong ground motions show measurable differences in shaking over scales of kilometers. Magnetic data show numerous NE-SW lineations, some which extend several tens of km to the northeast from near the aftershock plane, suggesting continuity of some features in that direction. Near the earthquake epicenter and primary aftershock plane, small changes in the orientation of major structures (< 20°) are apparent in magnetic, gravity and topographic data. Detailed analyses to understand possible relations are underway.

A Raman and Infrared Spectroscopic Study of Anglesite at High Pressures

NASA Astrophysics Data System (ADS)

Sawchuk, K. L. S.; Vennari, C.; O'Bannon, E. F., III; Williams, Q.

2016-12-01

Raman and infrared spectra of the barite-structured lead sulfate, anglesite (PbSO4), were collected to 40 GPa and 300 K. Our particular interest in this compound is oriented towards determining what post-barite structures sulfates in the deep earth sulfur cycle might ultimately convert to at high pressures. Additionally, the study of ABX4 materials has applications to materials science that include their usage as scintillation detectors, and PbSO4 has been demonstrated to have non-linear optical properties. Measurements were made of the internal modes of the SO4 group that lie between 400 and 1200 cm-1 and lattice vibrations that occur between 50 and 250 cm-1. In accord with previous Raman work of Lee et al. (WJCMP, 2012), two phase transitions initiate at 13 and 23 GPa which are reversible on decompression. The 13 GPa transition is subtle and involves splitting of a few modes, particularly the SO4 tetragonal stretching and bending-derived Raman and associated infrared modes. This transition likely goes to a structure with a greater degree of Davydov splitting between corresponding Raman- and infrared-active vibrations, which may indicate a greater distortion of the SO4 tetrahedra. The transition at 23 GPa is a major, sluggish, transition that causes splitting and/or shifting in all observed Raman and infrared modes. These new peaks are lower in frequency and become the sole spectral features by 42 GPa suggesting a higher symmetry structure than previously inferred. It appears that this transition involves a coexistence of phases until the transition is ultimately complete around 42 GPa. Based on the structural systematics of ABX4 phases and factor group analysis, it is likely the structure goes to the monazite structure at high pressures, but that this transition required marked overpressurization to occur at 300K. The accessing of this monazite-like phase is in general accord with systematics of high-pressure transitions in ABX4 phases, and indicates that monazite-structured polymorphs may be anticipated within subducted high-pressure sulfates within Earth's mantle.

Rational protein engineering in action: The first crystal structure of a phenylalanine tRNA synthetase from Staphylococcus haemolyticus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Evdokimov, Artem G.; Mekel, Marlene; Hutchings, Kim

2008-07-08

In this article, we describe for the first time the high-resolution crystal structure of a phenylalanine tRNA synthetase from the pathogenic bacterium Staphylococcus haemolyticus. We demonstrate the subtle yet important structural differences between this enzyme and the previously described Thermus thermophilus ortholog. We also explain the structure-activity relationship of several recently reported inhibitors. The native enzyme crystals were of poor quality -- they only diffracted X-rays to 3--5 {angstrom} resolution. Therefore, we have executed a rational surface mutagenesis strategy that has yielded crystals of this 2300-amino acid multidomain protein, diffracting to 2 {angstrom} or better. This methodology is discussed andmore » contrasted with the more traditional domain truncation approach.« less

From bacteria to elephants: Effects of land-use legacies on biodiversity and ecosystem structure in the Serengeti-Mara ecosystem: Chapter 8

USGS Publications Warehouse

Verchot, Louis V.; Ward, Naomi L.; Belnap, Jayne; Bossio, Deborah; Coughenour, Michael; Gibson, John; Hanotte, Olivier; Muchiru, Andrew N.; Phillips, Susan L.; Steven, Blaire; Wall, Diana H.; Reid, Robin S.

2015-01-01

Generally, ecological research has considered the aboveground and belowground components of ecosystems separately. Consequently, frameworks for integrating the two components are not well developed. Integrating the microbial components into ecosystem ecology requires different approaches from those offered by plant ecology, partly because of the scales at which microbial processes operate and partly because of measurement constraints. Studies have begun to relate microbial community structure to ecosystem function. results suggest that excluding people and livestock from the MMNR, or preventing heavier livestock from grazing around settlements, may not change the general structure of the ecosystem (soils, plant structure), but can change the numbers and diversity of wildlife, nematodes and microbes in this ecosystem in subtle ways.

Culture Wires the Brain: A Cognitive Neuroscience Perspective.

PubMed

Park, Denise C; Huang, Chih-Mao

2010-07-01

There is clear evidence that sustained experiences may affect both brain structure and function. Thus, it is quite reasonable to posit that sustained exposure to a set of cultural experiences and behavioral practices will affect neural structure and function. The burgeoning field of cultural psychology has often demonstrated the subtle differences in the way individuals process information-differences that appear to be a product of cultural experiences. We review evidence that the collectivistic and individualistic biases of East Asian and Western cultures, respectively, affect neural structure and function. We conclude that there is limited evidence that cultural experiences affect brain structure and considerably more evidence that neural function is affected by culture, particularly activations in ventral visual cortex-areas associated with perceptual processing. © The Author(s) 2010.

Challenges of Big Data Analysis.

PubMed

Fan, Jianqing; Han, Fang; Liu, Han

2014-06-01

Big Data bring new opportunities to modern society and challenges to data scientists. On one hand, Big Data hold great promises for discovering subtle population patterns and heterogeneities that are not possible with small-scale data. On the other hand, the massive sample size and high dimensionality of Big Data introduce unique computational and statistical challenges, including scalability and storage bottleneck, noise accumulation, spurious correlation, incidental endogeneity, and measurement errors. These challenges are distinguished and require new computational and statistical paradigm. This article gives overviews on the salient features of Big Data and how these features impact on paradigm change on statistical and computational methods as well as computing architectures. We also provide various new perspectives on the Big Data analysis and computation. In particular, we emphasize on the viability of the sparsest solution in high-confidence set and point out that exogeneous assumptions in most statistical methods for Big Data can not be validated due to incidental endogeneity. They can lead to wrong statistical inferences and consequently wrong scientific conclusions.

Massive pericardial effusion associated with hypothyroidism.

PubMed

Ionescu, Simona Daniela; Tănase, Daniela Maria; Ouatu, Anca; Ambăruş, V; Dosa, Anca; Arsenescu-Georgescu, Cătălina

2014-01-01

The diagnosis of hypothyroidism is difficult because hypothyroidism in adults and especially the elderly, classic, has an insidious onset with a range of nonspecific symptoms which may delay diagnosis for months or even years. Old age seems to represent trigger factor for autoimmune diseases, including hypothyroidism. Clinical features in hypothyroidism, such as weight gain, fatigue, cold intolerance, constipation, dry skin, edema and muscle weakness, and decreased osteo-tendinous reflexes are usually subtle and can be overlooked. Thyroid dysfunction may be associated with a negative impact on the cardiovascular system. Pericardial, pleural and peritoneal effusions are common findings in hypothyroidism. This case report represents a typical primary hypothyroidism (autoimmune) and shows the clinical features of this disease. Basically we talked about a severe myxedema with the involvement of internal organs in an elderly woman and the euthyroidism restoration, under thyroid replacement therapy, was correlated with the clinical improvement and cardiovascular and neurological status, with radiographic remission and regression to extinction of pericardial effusion at repeated echocardiographic evaluations.

Sheehan's Syndrome-The Most Common Cause of Panhypopituitarism at Moderate Altitude: A Sub-Himalayan Study.

PubMed

Mokta, Jatinder; Ranjan, Asha; Thakur, Surinder; Bhawani, Rajesh; Mokta, Kiran K; Sharma, Jai Bharat; Kumar, Manish

2017-12-01

Panhypopituitarism is a rare disorder with varied clinical presentation having various etiologies. Sheehan's syndrome (SS) is decreasing in frequency worldwide and is a rare cause of panhypopituitarism in developed nations. A retrospective study done between May 2011 and May 2015 in tertiary care hospital. We reviewed the records of patients with hypopituitarism. Clinical features, hormonal profile and radiological investigations noted. Total 14 patients of panhypopituitarism included with average duration of symptoms 1.93± 1.96 years. four (28.57%) were males and ten (71.43%) were females with mean age of diagnosis 37.78± 13.68 years. Sheehan's syndrome (SS) was the most common cause of panhypopituitarism in 57.14%(8 patients), followed by post surgery in 14.28% (2 patients). 80% of women had SS with a mean duration of symptoms 2.39±1.54 years. Sheehan's syndrome is not uncommon in developing countries, High degree of clinical suspicion is desired as clinical features are most often subtle.

Challenges of Big Data Analysis

PubMed Central

Fan, Jianqing; Han, Fang; Liu, Han

2014-01-01

Big Data bring new opportunities to modern society and challenges to data scientists. On one hand, Big Data hold great promises for discovering subtle population patterns and heterogeneities that are not possible with small-scale data. On the other hand, the massive sample size and high dimensionality of Big Data introduce unique computational and statistical challenges, including scalability and storage bottleneck, noise accumulation, spurious correlation, incidental endogeneity, and measurement errors. These challenges are distinguished and require new computational and statistical paradigm. This article gives overviews on the salient features of Big Data and how these features impact on paradigm change on statistical and computational methods as well as computing architectures. We also provide various new perspectives on the Big Data analysis and computation. In particular, we emphasize on the viability of the sparsest solution in high-confidence set and point out that exogeneous assumptions in most statistical methods for Big Data can not be validated due to incidental endogeneity. They can lead to wrong statistical inferences and consequently wrong scientific conclusions. PMID:25419469

Evolution of imaging for abdominal perforation

PubMed Central

Singh, JP; Steward, MJ; Booth, TC; Mukhtar, H; Murray, D

2010-01-01

INTRODUCTION Gastrointestinal (GI) perforation is a common surgical presentation. In recent years, computed tomography (CT) has been shown to be accurate for predicting the site of GI perforation, and has become the investigation of choice. However the signs may be subtle or only indirectly related to the site or aetiology of perforation. SUBJECTS AND METHODS A MEDLINE and PubMed search was performed for journals before June 2009 with MeSH major terms ‘CT’ and ‘perforation’. Non-English speaking literature was excluded. RESULTS Examples of GI perforation of various aetiologies are reviewed (inflammatory, neoplastic, traumatic and iatrogenic) high-lighting characteristic CT appearances as well as pitfalls in diagnosis. Features of perforation include the presence of free gas or fluid within the supra- and/or inframesocolic compartments, segmental bowel wall thickening, bowel wall discontinuity, stranding of the mesenteric fat and abscess formation. CONCLUSIONS These differentiating features facilitate accurate multidisciplinary pre-operative evaluation, necessary to plan patient management and potential surgical approach. PMID:20412668

Characterization of Interfacial Chemistry of Adhesive/Dentin Bond Using FTIR Chemical Imaging With Univariate and Multivariate Data Processing

PubMed Central

Wang, Yong; Yao, Xiaomei; Parthasarathy, Ranganathan

2008-01-01

Fourier transform infrared (FTIR) chemical imaging can be used to investigate molecular chemical features of the adhesive/dentin interfaces. However, the information is not straightforward, and is not easily extracted. The objective of this study was to use multivariate analysis methods, principal component analysis and fuzzy c-means clustering, to analyze spectral data in comparison with univariate analysis. The spectral imaging data collected from both the adhesive/healthy dentin and adhesive/caries-affected dentin specimens were used and compared. The univariate statistical methods such as mapping of intensities of specific functional group do not always accurately identify functional group locations and concentrations due to more or less band overlapping in adhesive and dentin. Apart from the ease with which information can be extracted, multivariate methods highlight subtle and often important changes in the spectra that are difficult to observe using univariate methods. The results showed that the multivariate methods gave more satisfactory, interpretable results than univariate methods and were conclusive in showing that they can discriminate and classify differences between healthy dentin and caries-affected dentin within the interfacial regions. It is demonstrated that the multivariate FTIR imaging approaches can be used in the rapid characterization of heterogeneous, complex structure. PMID:18980198

Combined experimental and theoretical study of fast atom diffraction on the β2(2×4) reconstructed GaAs(001) surface

NASA Astrophysics Data System (ADS)

Debiossac, M.; Zugarramurdi, A.; Khemliche, H.; Roncin, P.; Borisov, A. G.; Momeni, A.; Atkinson, P.; Eddrief, M.; Finocchi, F.; Etgens, V. H.

2014-10-01

A grazing incidence fast atom diffraction (GIFAD or FAD) setup, installed on a molecular beam epitaxy chamber, has been used to characterize the β2(2×4) reconstruction of a GaAs(001) surface at 530∘C under an As4 overpressure. Using a 400-eV 4He beam, high-resolution diffraction patterns with up to eighty well-resolved diffraction orders are observed simultaneously, providing a detailed fingerprint of the surface structure. Experimental diffraction data are in good agreement with results from quantum scattering calculations based on an ab initio projectile-surface interaction potential. Along with exact calculations, we show that a straightforward semiclassical analysis allows the features of the diffraction chart to be linked to the main characteristics of the surface reconstruction topography. Our results demonstrate that GIFAD is a technique suitable for measuring in situ the subtle details of complex surface reconstructions. We have performed measurements at very small incidence angles, where the kinetic energy of the projectile motion perpendicular to the surface can be reduced to less than 1 meV. This allowed the depth of the attractive van der Waals potential well to be estimated as -8.7 meV in very good agreement with results reported in literature.

Temporal association tracts and the breakdown of episodic memory in mild cognitive impairment

PubMed Central

Metzler-Baddeley, Claudia; Hunt, Sarah; Jones, Derek K.; Leemans, Alexander; Aggleton, John P.

2012-01-01

Objective: To examine the pattern of association between microstructure of temporal lobe connections and the breakdown of episodic memory that is a core feature of mild cognitive impairment (MCI). Methods: Twenty-five individuals with MCI and 20 matched controls underwent diffusion MRI and cognitive assessment. Three temporal pathways were reconstructed by tractography: fornix, parahippocampal cingulum (PHC), and uncinate fasciculus. Tissue volume fraction—a tract-specific measure of atrophy—and microstructural measures were derived for each tract. To test specificity of associations, a comparison tract (corticospinal tract) and control cognitive domains were also examined. Results: In MCI, tissue volume fraction was reduced in the fornix. Axial and radial diffusivity were increased in uncinate and PHC implying more subtle microstructural change. In controls, tissue volume fraction in the fornix was the predominant correlate of free recall. In contrast, in MCI, the strongest relationship was with left PHC. Microstructure of uncinate and PHC also correlated with recognition memory, and recognition confidence, in MCI. Conclusions: Episodic memory in MCI is related to the structure of multiple temporal association pathways. These associations are not confined to the fornix, as they are in healthy young and older adults. In MCI, because of a compromised fornix, alternative pathways may contribute disproportionally to episodic memory performance. PMID:23175726

Investigation of Coastal Hydrogeology Utilizing Geophysical and Geochemical Tools along the Broward County Coast, Florida

USGS Publications Warehouse

Reich, Christopher D.; Swarzenski, Peter W.; Greenwood, W. Jason; Wiese, Dana S.

2008-01-01

Geophysical (CHIRP, boomer, and continuous direct-current resistivity) and geochemical tracer studies (continuous and time-series 222Radon) were conducted along the Broward County coast from Port Everglades to Hillsboro Inlet, Florida. Simultaneous seismic, direct-current resistivity, and radon surveys in the coastal waters provided information to characterize the geologic framework and identify potential groundwater-discharge sites. Time-series radon at the Nova Southeastern University National Coral Reef Institute (NSU/NCRI) seawall indicated a very strong tidally modulated discharge of ground water with 222Rn activities ranging from 4 to 10 disintegrations per minute per liter depending on tidal stage. CHIRP seismic data provided very detailed bottom profiles (i.e., bathymetry); however, acoustic penetration was poor and resulted in no observed subsurface geologic structure. Boomer data, on the other hand, showed features that are indicative of karst, antecedent topography (buried reefs), and sand-filled troughs. Continuous resistivity profiling (CRP) data showed slight variability in the subsurface along the coast. Subtle changes in subsurface resistivity between nearshore (higher values) and offshore (lower values) profiles may indicate either a freshening of subsurface water nearshore or a change in sediment porosity or lithology. Further lithologic and hydrologic controls from sediment or rock cores or well data are needed to constrain the variability in CRP data.

Effects of tissue fixation and dehydration on tendon collagen nanostructure.

PubMed

Turunen, Mikael J; Khayyeri, Hanifeh; Guizar-Sicairos, Manuel; Isaksson, Hanna

2017-09-01

Collagen is the most prominent protein in biological tissues. Tissue fixation is often required for preservation or sectioning of the tissue. This may affect collagen nanostructure and potentially provide incorrect information when analyzed after fixation. We aimed to unravel the effect of 1) ethanol and formalin fixation and 2) 24h air-dehydration on the organization and structure of collagen fibers at the nano-scale using small and wide angle X-ray scattering. Samples were divided into 4 groups: ethanol fixed, formalin fixed, and two untreated sample groups. Samples were allowed to air-dehydrate in handmade Kapton pockets during the measurements (24h) except for one untreated group. Ethanol fixation affected the collagen organization and nanostructure substantially and during 24h of dehydration dramatic changes were evident. Formalin fixation had minor effects on the collagen organization but after 12h of air-dehydration the spatial variation increased substantially, not evident in the untreated samples. Generally, collagen shrinkage and loss of alignment was evident in all samples during 24h of dehydration but the changes were subtle in all groups except the ethanol fixed samples. This study shows that tissue fixation needs to be chosen carefully in order to preserve the features of interest in the tissue. Copyright © 2017 Elsevier Inc. All rights reserved.

Segmentation of images for gingival growth measurement

NASA Astrophysics Data System (ADS)

Kim, Dong-Il; Wilson, Joseph N.

1992-12-01

The ability to measure gingival volume growth from dental casts would provide a valuable resource for periodontists. This problem is attractive from a computer vision standpoint due to the complexities of data acquisition, segmentation of gingival and tooth surfaces and boundaries, and extraction of features (such as tooth axes) to help solve the correspondence problem for multiple casts. In this paper, a structured light 3-D range finder is used to collect raw data. The most complicated subtask is that of detecting discontinuities such as the gingival margin. Discontinuity detection is hindered both by cast anomalies (such as bubbles and holes generated during the process of dental impression) and by the subtle nature of the discontinuities themselves. First, we discuss an approach to segmenting a dental cast into tooth and gingival units using depth and orientation discontinuities. The visible cast surface is reconstructed by obtaining the minimum of a parameterized functional. The first derivative of the energy functional (which corresponds to the Euler-Lagrange equation) is solved using the multigrid methods. both orientation and depth discontinuities are detected by adding a discrete discontinuity functional to the energy functional. The principal axes and boundaries of the teeth provide the information necessary to determine the region to be measured in estimating gingival growth. Finally, voxels corresponding to growth regions are counted to measure the target volume.

MiniFluo fluorescence sensor, advances in FDOM Ocean Measurements

NASA Astrophysics Data System (ADS)

Cyr, Frédéric; Tedetti, Marc; Goutx, Madeleine

2017-04-01

As part of the European project "Next generation Low-Cost Multifunctional Web Enabled Ocean Sensor Systems Empowering Marine, Maritime and Fisheries Management (NeXOS)", we developed the MiniFluo, a glider-compatible optical sensor for measurements of fluorescent dissolved organic matter (FDOM). In situ applications of the MiniFluo are presented here. The configuration used targets both natural (Tryptophan) and an anthropogenic (Phenanthrene) DOM fluorophores. Observations from three glider campaigns in the NW Mediterranean (Fall 2015 and Spring and Summer 2016) are presented. It is shown that the use of the Minifluo highlights new features of DOM dynamics in the region. For example, the Tryptophan (an amino-acid traditionally used as a tracer for waste waters) is found here closely related to open sea Chl-a fluorescence. Differences between Chl-a and Tryptophan fluorescence also give subtle information on seasonal changes in ecosystem structure and DOM release that could not be observed with traditional glider measurements. The study also highlights the presence of phenanthrene (an anthropogenic polycyclic aromatic hydrocarbon (PAH) in the surface and sub-surface waters of the Mediterranean. Implications of these finding will be put in the context of both the Mediterranean Sea DOM dynamics and also the ocean carbon cycle, from which the Dissolved Organic Carbon pool remains qualitatively unknown.

Multi-channel acoustic recording and automated analysis of Drosophila courtship songs

PubMed Central

2013-01-01

Background Drosophila melanogaster has served as a powerful model system for genetic studies of courtship songs. To accelerate research on the genetic and neural mechanisms underlying courtship song, we have developed a sensitive recording system to simultaneously capture the acoustic signals from 32 separate pairs of courting flies as well as software for automated segmentation of songs. Results Our novel hardware design enables recording of low amplitude sounds in most laboratory environments. We demonstrate the power of this system by collecting, segmenting and analyzing over 18 hours of courtship song from 75 males from five wild-type strains of Drosophila melanogaster. Our analysis reveals previously undetected modulation of courtship song features and extensive natural genetic variation for most components of courtship song. Despite having a large dataset with sufficient power to detect subtle modulations of song, we were unable to identify previously reported periodic rhythms in the inter-pulse interval of song. We provide detailed instructions for assembling the hardware and for using our open-source segmentation software. Conclusions Analysis of a large dataset of acoustic signals from Drosophila melanogaster provides novel insight into the structure and dynamics of species-specific courtship songs. Our new system for recording and analyzing fly acoustic signals should therefore greatly accelerate future studies of the genetics, neurobiology and evolution of courtship song. PMID:23369160

Navigating condom use and HIV status disclosure with partners met online: a qualitative pilot study with gay and bisexual men from Craigslist.org.

PubMed

Grov, Christian; Agyemang, Linda; Ventuneac, Ana; Breslow, Aaron S

2013-02-01

We conducted face-to-face semi-structured interviews with 50 men recruited from the New York City men-seeking-men section of Craigslist.org. Participants discussed their favorite venues for meeting sex partners (n = 28 said the Internet), and we focused on these men's responses to probes regarding decisions around condom use and HIV status disclosure with online partners. A majority indicated they set a priori rules for themselves to always use condoms, and they cited the Internet as their favorite venue in part because it helped them sort for like-minded partners. Participants indicated that having in-person conversations around condom use and HIV was often difficult, and that the Internet was a convenient medium to facilitate the process. Notable differences were observed in how HIV-positive and HIV-negative men navigated serostatus disclosure-HIV-negative men were less subtle in starting the conversation. Finally, participants described a common narrative around distrust with online partners, which is one reason why they consistently use condoms. These data suggest that features which allow men to easily indicate, and filter for, condom use preferences should be built into (or maintained on) profile-based sexual networking sites and sexual bulletin board sites.

Exploring healthcare communication models in private physiotherapy practice.

PubMed

Hiller, Amy; Guillemin, Marilys; Delany, Clare

2015-10-01

This project explored whether models of healthcare communication are evident within patient-physiotherapist communication in the private practice setting. Using qualitative ethnographic methods, fifty-two patient-physiotherapist treatment sessions were observed and interviews with nine physiotherapists were undertaken. Data were analyzed using thematic analysis. In these clinical encounters physiotherapists led the communication. The communication was structured and focussed on physical aspects of the patient's presentation. These features were mediated via casual conversation and the use of touch to respond to the individual patient. Physiotherapists did not explicitly link their therapeutic communication style to established communication models. However, they described a purposeful approach to how they communicated within the treatment encounter. The communication occurring in the private practice physiotherapy treatment encounter is predominantly representative of a 'practitioner-centred' model. However, the subtle use of touch and casual conversation implicitly communicate competence and care, representative of a patient-centred model. Physiotherapists do not explicitly draw from theories of communication to inform their practice. Physiotherapists may benefit from further education to achieve patient-centred communication. Equally, the incorporation of casual conversation and the use of touch into theory of physiotherapy patient-centred communication would highlight these specific skills that physiotherapists already utilize in practice. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Unveiling the control of quenched disorder in rare earth nickelates

NASA Astrophysics Data System (ADS)

Das, Sarmistha; Phanindra, V. Eswara; Philip, Sharon S.; Rana, D. S.

2017-10-01

The role of quenched disorder, a key control to obtain novel phases and functionalities, has not yet been determined in the complex phase diagram of RNi O3 (R = rare-earth ion) perovskites. Here we present such a study by investigating (L a0.5E u0.5 ) Ni O3 (LENO) having large R-site cation disorder. We show that in the presence of quenched disorder, (i) the resistivity drops by a few orders of magnitude across the metal-insulator transition (MIT) but the MIT shows only a subtle decrease, (ii) compressive films are completely metallic while largely tensile films are completely insulating sans a MIT, (iii) orthorhombic distortion promotes sharp MIT, and (iv) a Fermi liquid behavior even as high temperature resistivity exceeds the Mott-Ioffe-Regel limit with a bad metallic state. The low-energy terahertz conductivity dynamics obey Drude and Drude-Smith models for compressive and tensile films, respectively. All these features of disordered LENO, which are not typical of prototype ordered NdNi O3 , reveal an extraordinary sensitivity to slight structural perturbations. This study depicts the ease with which a variety of electronic phases can be tuned in disordered nickelates and emphasize the need to incorporate quenched disorder as a key control in the phase diagram of nickelates.

Spin excitations used to probe the nature of exchange coupling in the magnetically ordered ground state of Pr 0.5 Ca 0.5 MnO 3

DOE PAGES

Ewings, R. A.; Perring, T. G.; Sikora, O.; ...

2016-07-06

We have used time-of-flight inelastic neutron scattering to measure the spin wave spectrum of the canonical half-doped manganite Pr 0.5Ca 0.5MnO 3 in its magnetic and orbitally ordered phase. Comparison of the data, which cover multiple Brillouin zones and the entire energy range of the excitations, with several different models shows that only the CE-type ordered state provides an adequate description of the magnetic ground state, provided interactions beyond nearest neighbor are included. We are able to rule out a ground state in which there exist pairs of dimerized spins which interact only with their nearest neighbors. The Zener polaronmore » ground state, which comprises strongly bound magnetic dimers, can be ruled out on the basis of gross features of the observed spin wave spectrum. A model with weaker dimerization reproduces the observed dispersion but can be ruled out on the basis of subtle discrepancies between the calculated and observed structure factors at certain positions in reciprocal space. Adding further neighbor interactions results in almost no dimerization, i.e. interpolating back to the CE model. These results are consistent with theoretical analysis of the degenerate double exchange model for half-doping.« less

Abnormal Neural Activation to Faces in the Parents of Children with Autism.

PubMed

Yucel, G H; Belger, A; Bizzell, J; Parlier, M; Adolphs, R; Piven, J

2015-12-01

Parents of children with an autism spectrum disorder (ASD) show subtle deficits in aspects of social behavior and face processing, which resemble those seen in ASD, referred to as the "Broad Autism Phenotype " (BAP). While abnormal activation in ASD has been reported in several brain structures linked to social cognition, little is known regarding patterns in the BAP. We compared autism parents with control parents with no family history of ASD using 2 well-validated face-processing tasks. Results indicated increased activation in the autism parents to faces in the amygdala (AMY) and the fusiform gyrus (FG), 2 core face-processing regions. Exploratory analyses revealed hyper-activation of lateral occipital cortex (LOC) bilaterally in autism parents with aloof personality ("BAP+"). Findings suggest that abnormalities of the AMY and FG are related to underlying genetic liability for ASD, whereas abnormalities in the LOC and right FG are more specific to behavioral features of the BAP. Results extend our knowledge of neural circuitry underlying abnormal face processing beyond those previously reported in ASD to individuals with shared genetic liability for autism and a subset of genetically related individuals with the BAP. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Interpersonal sensitivity and persistent attenuated psychotic symptoms in adolescence.

PubMed

Masillo, Alice; Brandizzi, M; Valmaggia, L R; Saba, R; Lo Cascio, N; Lindau, J F; Telesforo, L; Venturini, P; Montanaro, D; Di Pietro, D; D'Alema, M; Girardi, P; Fiori Nastro, P

2018-03-01

Interpersonal sensitivity defines feelings of inner-fragility in the presence of others due to the expectation of criticism or rejection. Interpersonal sensitivity was found to be related to attenuated positive psychotic symptom during the prodromal phase of psychosis. The aims of this study were to examine if high level of interpersonal sensitivity at baseline are associated with the persistence of attenuated positive psychotic symptoms and general psychopathology at 18-month follow-up. A sample of 85 help-seeking individuals (mean age = 16.6, SD = 5.05) referred an Italian early detection project, completed the interpersonal sensitivity measure and the structured interview for prodromal symptoms (SIPS) at baseline and were assessed at 18-month follow-up using the SIPS. Results showed that individuals with high level of interpersonal sensitivity at baseline reported high level of attenuated positive psychotic symptoms (i.e., unusual thought content) and general symptoms (i.e., depression, irritability and low tolerance to daily stress) at follow-up. This study suggests that being "hypersensitive" to interpersonal interactions is a psychological feature associated with attenuated positive psychotic symptoms and general symptoms, such as depression and irritability, at 18-month follow-up. Assessing and treating inner-self fragilities may be an important step of early detection program to avoid the persistence of subtle but very distressing long-terms symptoms.

Multi-contrast light profile microscopy for the depth-resolved imaging of the properties of multi-ply thin films.

PubMed

Power, J F

2009-06-01

Light profile microscopy (LPM) is a direct method for the spectral depth imaging of thin film cross-sections on the micrometer scale. LPM uses a perpendicular viewing configuration that directly images a source beam propagated through a thin film. Images are formed in dark field contrast, which is highly sensitive to subtle interfacial structures that are invisible to reference methods. The independent focusing of illumination and imaging systems allows multiple registered optical sources to be hosted on a single platform. These features make LPM a powerful multi-contrast (MC) imaging technique, demonstrated in this work with six modes of imaging in a single instrument, based on (1) broad-band elastic scatter; (2) laser excited wideband luminescence; (3) coherent elastic scatter; (4) Raman scatter (three channels with RGB illumination); (5) wavelength resolved luminescence; and (6) spectral broadband scatter, resolved in immediate succession. MC-LPM integrates Raman images with a wider optical and morphological picture of the sample than prior art microprobes. Currently, MC-LPM resolves images at an effective spectral resolution better than 9 cm(-1), at a spatial resolution approaching 1 microm, with optics that operate in air at half the maximum numerical aperture of the prior art microprobes.

GUTs on Compact Type IIB Orientifolds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blumenhagen, Ralph; /Munich, Max Planck Inst.; Braun, Volker

We systematically analyze globally consistent SU(5) GUT models on intersecting D7-branes in genuine Calabi-Yau orientifolds with O3- and O7-planes. Beyond the well-known tadpole and K-theory cancellation conditions there exist a number of additional subtle but quite restrictive constraints. For the realization of SU(5) GUTs with gauge symmetry breaking via U(1)Y flux we present two classes of suitable Calabi-Yau manifolds defined via del Pezzo transitions of the elliptically fibred hypersurface P{sub 1,1,1,6,9}[18] and of the Quintic P{sub 1,1,1,1,1}[5], respectively. To define an orientifold projection we classify all involutions on del Pezzo surfaces. We work out the model building prospects of thesemore » geometries and present five globally consistent string GUT models in detail, including a 3-generation SU(5) model with no exotics whatsoever. We also realize other phenomenological features such as the 10 10 5{sub H} Yukawa coupling and comment on the possibility of moduli stabilization, where we find an entire new set of so-called swiss-cheese type Calabi-Yau manifolds. It is expected that both the general constrained structure and the concrete models lift to F-theory vacua on compact Calabi-Yau fourfolds.« less

Investigating Subtle Colors on Iapetus

NASA Image and Video Library

2015-04-06

NASA Cassini spacecraft stared toward Saturn two-toned moon Iapetus for about a week in early 2015, in a campaign motivated in part to investigate subtle color differences within the moon bright terrain.

Breast cancer risk assessment and diagnosis model using fuzzy support vector machine based expert system

NASA Astrophysics Data System (ADS)

Dheeba, J.; Jaya, T.; Singh, N. Albert

2017-09-01

Classification of cancerous masses is a challenging task in many computerised detection systems. Cancerous masses are difficult to detect because these masses are obscured and subtle in mammograms. This paper investigates an intelligent classifier - fuzzy support vector machine (FSVM) applied to classify the tissues containing masses on mammograms for breast cancer diagnosis. The algorithm utilises texture features extracted using Laws texture energy measures and a FSVM to classify the suspicious masses. The new FSVM treats every feature as both normal and abnormal samples, but with different membership. By this way, the new FSVM have more generalisation ability to classify the masses in mammograms. The classifier analysed 219 clinical mammograms collected from breast cancer screening laboratory. The tests made on the real clinical mammograms shows that the proposed detection system has better discriminating power than the conventional support vector machine. With the best combination of FSVM and Laws texture features, the area under the Receiver operating characteristic curve reached .95, which corresponds to a sensitivity of 93.27% with a specificity of 87.17%. The results suggest that detecting masses using FSVM contribute to computer-aided detection of breast cancer and as a decision support system for radiologists.

Juling and Kupalo Craters

NASA Image and Video Library

2017-08-17

This region on Ceres, located in the vicinity of Toharu Crater, presents two small craters: Juling at top (12 miles, 20 kilometers in diameter) and Kupalo at bottom (16 miles, 26 kilometers in diameter). Both craters are relatively young, as indicated by their sharp rims. These features are located at about the same latitude (about 38 degrees south) as Tawals Crater and show similar crater shapes and rugged terrain. These features may reflect the presence of ice below the surface. Subtle bright features can be distinguished in places. These likely were excavated by small impacts and landslides along the slopes of the crater rims. This suggests that a different type of material, likely rich in salts, is present in the shallow subsurface. Juling is named after the Sakai/Orang Asli spirit of the crops from Malaysia, and Kupalo gets its name from the Russian god of vegetation and of the harvest. NASA's Dawn spacecraft acquired this picture on August 24, 2016. The image was taken during Dawn's extended mission, from its low altitude mapping orbit at about 240 miles (385 kilometers) above the surface. The center coordinates of this image are 38 degrees south latitude, 165 degrees east longitude. https://photojournal.jpl.nasa.gov/catalog/PIA21753

Subtle Distinctions: How Attentional Templates Influence EEG Parameters of Cognitive Control in a Spatial Cuing Paradigm

PubMed Central

Mertes, Christine; Schneider, Daniel

2018-01-01

Using event-related potentials (ERPs) of the electroencephalogram, we investigated how cognitive control is altered by the scope of an attentional template currently activated in visual working memory. Participants performed a spatial cuing task where an irrelevant color singleton cue was presented prior to a target array. Blockwise, the target was either a red circle or a gray square and had to be searched within homogenous (gray circles) or heterogeneous non-targets (differently colored circles or various shapes). Thereby we aimed to trigger the adoption of different attentional templates: a broader singleton or a narrower, more specific feature template. ERP markers of attentional selection and inhibitory control showed that the amount of cognitive control was overall enhanced when participants searched on the basis of a feature-specific template: the analysis revealed reduced selection (N2pc, frontal P2) and pronounced inhibition (negative shift of frontal N2) of the irrelevant color cue when participants searched for a feature target. On behavioral level attentional capture was most pronounced in the color condition with no differentiation between the task-induced scopes of the attentional template. PMID:29628884

Tolerance for distorted faces: challenges to a configural processing account of familiar face recognition.

PubMed

Sandford, Adam; Burton, A Mike

2014-09-01

Face recognition is widely held to rely on 'configural processing', an analysis of spatial relations between facial features. We present three experiments in which viewers were shown distorted faces, and asked to resize these to their correct shape. Based on configural theories appealing to metric distances between features, we reason that this should be an easier task for familiar than unfamiliar faces (whose subtle arrangements of features are unknown). In fact, participants were inaccurate at this task, making between 8% and 13% errors across experiments. Importantly, we observed no advantage for familiar faces: in one experiment participants were more accurate with unfamiliars, and in two experiments there was no difference. These findings were not due to general task difficulty - participants were able to resize blocks of colour to target shapes (squares) more accurately. We also found an advantage of familiarity for resizing other stimuli (brand logos). If configural processing does underlie face recognition, these results place constraints on the definition of 'configural'. Alternatively, familiar face recognition might rely on more complex criteria - based on tolerance to within-person variation rather than highly specific measurement. Copyright © 2014 Elsevier B.V. All rights reserved.

‘I wouldn’t say it’s sexism, except that … It’s all these little subtle things’: Healthcare scientists’ accounts of gender in healthcare science laboratories

PubMed Central

Learmonth, Mark

2013-01-01

We explore healthcare scientists’ accounts of men in healthcare science laboratories. By focussing on subtle masculinist actions that women find disadvantageous to them, we seek to extend knowledge about women’s under-representation in senior positions in healthcare science – despite women being in the majority at junior levels. We maintain that healthcare science continues to be dominated by taken-for-granted masculinities that marginalize women, keeping them in their ‘place’. Our aim is to make visible the subtle practices that are normally invisible by showing masculinities in action. Principally using feminist analyses, our findings show that both women and men are often unaware of taken-for-granted masculinist actions, and even when women do notice, they rarely challenge the subtle sexist behaviour.

Structure and Thermodynamics of Polyolefin Melts

NASA Astrophysics Data System (ADS)

Weinhold, J. D.; Curro, J. G.; Habenschuss, A.; Londono, J. D.

1997-03-01

Subtle differences in the intermolecular packing of various polyolefins can create dissimilar permeability and mixing behavior. We have used a combination of the Polymer Reference Interaction Site Model (PRISM) and Monte Carlo simulation to study the structural and thermodynamic properties of realistic models for polyolefins. Results for polyisobutylene and syndiotactic polypropylene will be presented along with comparisons to wide-angle x-ray scattering experiments and properties determined from previous studies of polyethylene and isotactic polypropylene. Our technique uses a Monte Carlo simulation on an isolated molecule to determine the polymer's intramolecular structure. With this information, PRISM theory can predict the intermolecular packing for any liquid density and/or mixture composition in a computationally efficient manner. This approach will then be used to explore the mixing behavior of these polyolefins.

Crowding, Entropic Forces, and Confinement: Crucial Factors for Structures and Functions in the Cell Nucleus.

PubMed

Hancock, R

2018-04-01

The view of the cell nucleus as a crowded system of colloid particles and that chromosomes are giant self-avoiding polymers is stimulating rapid advances in our understanding of its structure and activities, thanks to concepts and experimental methods from colloid, polymer, soft matter, and nano sciences and to increased computational power for simulating macromolecules and polymers. This review summarizes current understanding of some characteristics of the molecular environment in the nucleus, of how intranuclear compartments are formed, and of how the genome is highly but precisely compacted, and underlines the crucial, subtle, and sometimes unintuitive effects on structures and reactions of entropic forces caused by the high concentration of macromolecules in the nucleus.

Interactive Particle Visualization

NASA Astrophysics Data System (ADS)

Gribble, Christiaan P.

Particle-based simulation methods are used to model a wide range of complex phenomena and to solve time-dependent problems of various scales. Effective visualizations of the resulting state will communicate subtle changes in the three-dimensional structure, spatial organization, and qualitative trends within a simulation as it evolves. This chapter discusses two approaches to interactive particle visualization that satisfy these goals: one targeting desktop systems equipped with programmable graphics hardware, and the other targeting moderately sized multicore systems using packet-based ray tracing.

Generalized Sheet Transition Conditions for a Metascreen—A Fishnet Metasurface

NASA Astrophysics Data System (ADS)

Holloway, Christopher L.; Kuester, Edward F.

2018-05-01

We used a multiple-scale homogenization method to derive generalized sheet transition conditions (GSTCs) for electromagnetic fields at the surface of a metascreen---a metasurface with a "fishnet" structure. These surfaces are characterized by periodically-spaced arbitrary-shaped apertures in an otherwise relatively impenetrable surface. The parameters in these GSTCs are interpreted as effective surface susceptibilities and surface porosities, which are related to the geometry of the apertures that constitute the metascreen. Finally, we emphasize the subtle but important difference between the GSTCs required for metascreens and those required for metafilms (a metasurface with a "cermet" structure, i.e., an array of isolated (non-touching) scatterers).

Angiogenesis - a crucial step in breast cancer growth, progression and dissemination by Raman imaging

NASA Astrophysics Data System (ADS)

Kopeć, Monika; Abramczyk, Halina

2018-06-01

Combined micro-Raman imaging and AFM imaging are efficient methods for analyzing human tissue due to their high spatial and spectral resolution as well as sensitivity to subtle chemical, structural and topographical changes. The aim of this study was to determine biochemical composition and mechanical topography around blood vessels in the tumor mass of human breast tissue. Significant alterations of the chemical composition and structural architecture around the blood vessel were found compared to the normal breast tissue. A pronounced increase of collagen-fibroblast-glycocalyx network, as well as enhanced lactic acid, and glycogen activity in patients affected by breast cancer were reported.