Object detection via eye tracking and fringe restraint

NASA Astrophysics Data System (ADS)

Pan, Fei; Zhang, Hanming; Zeng, Ying; Tong, Li; Yan, Bin

2017-07-01

Object detection is a computer vision problem which caught a large amount of attention. But the candidate boundingboxes extracted from only image features may end up with false-detection due to the semantic gap between the top-down and the bottom up information. In this paper, we propose a novel method for generating object bounding-boxes proposals using the combination of eye fixation point, saliency detection and edges. The new method obtains a fixation orientated Gaussian map, optimizes the map through single-layer cellular automata, and derives bounding-boxes from the optimized map on three levels. Then we score the boxes by combining all the information above, and choose the box with the highest score to be the final box. We perform an evaluation of our method by comparing with previous state-ofthe art approaches on the challenging POET datasets, the images of which are chosen from PASCAL VOC 2012. Our method outperforms them on small scale objects while comparable to them in general.

Which brain networks related to art perception are we talking about?. Comment on "Move me, astonish me…" delight my eyes and brain: The Vienna Integrated Model of top-down and bottom-up processes in Art Perception (VIMAP) and corresponding affective, evaluative, and neurophysiological correlates; by Matthew Pelowski et al.

NASA Astrophysics Data System (ADS)

Ayala, Francisco J.; Cela-Conde, Camilo J.

2017-07-01

The proposal by the Vienna Integrated Model of Art Perception (Pelowski et al., [4]; VIMAP, hereafter) is a valuable and much needed attempt to summarize and understand the cognitive processes underlying art perception. Very important in their model is, as expected, to ascertain the psychological and brain processes correlated with the perception of beauty in art works. In this commentary we'll focus exclusively on the consideration of VIMAP's section 5, ;Model stages and corresponding areas of the brain.; We'll examine the evidence advanced by VIMAP in the section about brain networks related to the perception of art.

Leadership & Spirit: Rejuvenating an Organization from the Bottom Up.

ERIC Educational Resources Information Center

Dance, Terry

Using a case study which documents the creation of the Access and Program Development Division at George Brown College, a large urban community college in Ontario, Canada, this paper explores the nature of leadership in educational management. Introductory material argues that leadership in management should be defined as a performing art rather…

Art on the Nanoscale and Beyond.

PubMed

Yetisen, Ali K; Coskun, Ahmet F; England, Grant; Cho, Sangyeon; Butt, Haider; Hurwitz, Jonty; Kolle, Mathias; Khademhosseini, Ali; Hart, A John; Folch, Albert; Yun, Seok Hyun

2016-03-02

Methods of forming and patterning materials at the nano- and microscales are finding increased use as a medium of artistic expression, and as a vehicle for communicating scientific advances to a broader audience. While sharing many attributes of other art forms, miniaturized art enables the direct engagement of sensory aspects such as sight and touch for materials and structures that are otherwise invisible to the eye. The historical uses of nano-/microscale materials and imaging techniques in arts and sciences are presented. The motivations to create artwork at small scales are discussed, and representations in scientific literature and exhibitions are explored. Examples are presented using semiconductors, microfluidics, and nanomaterials as the artistic media; these utilized techniques including micromachining, focused ion beam milling, two-photon polymerization, and bottom-up nanostructure growth. Finally, the technological factors that limit the implementation of artwork at miniature scales are identified, and potential future directions are discussed. As research marches toward even smaller length scales, innovative and engaging visualizations and artistic endeavors will have growing implications on education, communication, policy making, media activism, and public perception of science and technology. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bottom-Up Guidance in Visual Search for Conjunctions

ERIC Educational Resources Information Center

Proulx, Michael J.

2007-01-01

Understanding the relative role of top-down and bottom-up guidance is crucial for models of visual search. Previous studies have addressed the role of top-down and bottom-up processes in search for a conjunction of features but with inconsistent results. Here, the author used an attentional capture method to address the role of top-down and…

Shaping Children's Artwork in English Primary Classes: Insights from Teacher-Child Interaction during Art Activities

ERIC Educational Resources Information Center

Hallam, Jenny; Gupta, Mani Das; Lee, Helen

2011-01-01

This paper utilises a Vygotskian framework to examine the ways in which teachers shape the creation of children's artwork in educational contexts. Reflexive ethnography and a bottom up approach to discourse analysis are used to analyse a range of qualitative data including photographs, observational notes and audio recordings collected from a Year…

Cluster-assembled metallic glasses

PubMed Central

2013-01-01

A bottom-up approach to nanofabricate metallic glasses from metal clusters as building blocks is presented. Considering metallic glasses as a subclass of cluster-assembled materials, the relation between the two lively fields of metal clusters and metallic glasses is pointed out. Deposition of selected clusters or collections of them, generated by state-of-the-art cluster beam sources, could lead to the production of a well-defined amorphous material. In contrast to rapidly quenched glasses where only the composition of the glass can be controlled, in cluster-assembled glasses, one can precisely control the structural building blocks. Comparing properties of glasses with similar compositions but differing in building blocks and therefore different in structure will facilitate the study of structure–property correlation in metallic glasses. This bottom-up method provides a novel alternative path to the synthesis of glassy alloys and will contribute to improving fundamental understanding in the field of metallic glasses. It may even permit the production of glassy materials for alloys that cannot be quenched rapidly enough to circumvent crystallization. Additionally, gaining deeper insight into the parameters governing the structure–property relation in metallic glasses can have a great impact on understanding and design of other cluster-assembled materials. PMID:23899019

Dual Low-Rank Pursuit: Learning Salient Features for Saliency Detection.

PubMed

Lang, Congyan; Feng, Jiashi; Feng, Songhe; Wang, Jingdong; Yan, Shuicheng

2016-06-01

Saliency detection is an important procedure for machines to understand visual world as humans do. In this paper, we consider a specific saliency detection problem of predicting human eye fixations when they freely view natural images, and propose a novel dual low-rank pursuit (DLRP) method. DLRP learns saliency-aware feature transformations by utilizing available supervision information and constructs discriminative bases for effectively detecting human fixation points under the popular low-rank and sparsity-pursuit framework. Benefiting from the embedded high-level information in the supervised learning process, DLRP is able to predict fixations accurately without performing the expensive object segmentation as in the previous works. Comprehensive experiments clearly show the superiority of the proposed DLRP method over the established state-of-the-art methods. We also empirically demonstrate that DLRP provides stronger generalization performance across different data sets and inherits the advantages of both the bottom-up- and top-down-based saliency detection methods.

Neurophysiology of spectrotemporal cue organization of spoken language in auditory memory.

PubMed

Moberly, Aaron C; Bhat, Jyoti; Welling, D Bradley; Shahin, Antoine J

2014-03-01

Listeners assign different weights to spectral dynamics, such as formant rise time (FRT), and temporal dynamics, such as amplitude rise time (ART), during phonetic judgments. We examined the neurophysiological basis of FRT and ART weighting in the /ba/-/wa/ contrast. Electroencephalography was recorded for thirteen adult English speakers during a mismatch negativity (MMN) design using synthetic stimuli: a /ba/ with /ba/-like FRT and ART; a /wa/ with /wa/-like FRT and ART; and a /ba/(wa) with /ba/-like FRT and /wa/-like ART. We hypothesized that because of stronger reliance on FRT, subjects would encode a stronger memory trace and exhibit larger MMN during the FRT than the ART contrast. Results supported this hypothesis. The effect was most robust in the later portion of MMN. Findings suggest that MMN is generated by multiple sources, differentially reflecting acoustic change detection (earlier MMN, bottom-up process) and perceptual weighting of ART and FRT (later MMN, top-down process). Copyright © 2014 Elsevier Inc. All rights reserved.

Bottom-up guidance in visual search for conjunctions.

PubMed

Proulx, Michael J

2007-02-01

Understanding the relative role of top-down and bottom-up guidance is crucial for models of visual search. Previous studies have addressed the role of top-down and bottom-up processes in search for a conjunction of features but with inconsistent results. Here, the author used an attentional capture method to address the role of top-down and bottom-up processes in conjunction search. The role of bottom-up processing was assayed by inclusion of an irrelevant-size singleton in a search for a conjunction of color and orientation. One object was uniquely larger on each trial, with chance probability of coinciding with the target; thus, the irrelevant feature of size was not predictive of the target's location. Participants searched more efficiently for the target when it was also the size singleton, and they searched less efficiently for the target when a nontarget was the size singleton. Although a conjunction target cannot be detected on the basis of bottom-up processing alone, participants used search strategies that relied significantly on bottom-up guidance in finding the target, resulting in interference from the irrelevant-size singleton.

Analysis of Academic and Non-Academic Outcomes from a Bottom-up Comprehensive School Reform in the Absence of Student Level Data through Simulation Methods: A Mixed Methods Case Study

ERIC Educational Resources Information Center

Sondergeld, Toni A.

2009-01-01

This dissertation examines the efficacy of a bottom-up comprehensive school reform (CSR) program by evaluating its impact on student achievement, attendance, and behavior outcomes through an explanatory mixed methods design. The CSR program (Gear Up) was implemented in an urban junior high school over the course of seven years allowing for…

Pivots - A Bottom-Up Approach to Enhance Resilience

DTIC Science & Technology

2015-12-01

similar to a business incubator) to provide entrepreneurs with tools and resources to withstand disaster. Case studies and best practices identify...Salve Regina University, 2013 Submitted in partial fulfillment of the requirements for the degree of MASTER OF ARTS IN SECURITY STUDIES ...business incubator) to provide entrepreneurs with tools and resources to withstand disaster. Case studies and best practices identify and inform models of

Improving Reading Fluency and Comprehension in Adult ESL Learners Using Bottom-Up and Top-Down Vocabulary Training

ERIC Educational Resources Information Center

Oliver, Rhonda; Young, Shahreen

2016-01-01

The current research examines the effect of two methods of vocabulary training on reading fluency and comprehension of adult English as second language (ESL) tertiary-bound students. The methods used were isolated vocabulary training (bottom-up reading) and vocabulary training in context (top-down reading). The current exploratory and…

Nanoelectronics from the bottom up.

PubMed

Lu, Wei; Lieber, Charles M

2007-11-01

Electronics obtained through the bottom-up approach of molecular-level control of material composition and structure may lead to devices and fabrication strategies not possible with top-down methods. This review presents a brief summary of bottom-up and hybrid bottom-up/top-down strategies for nanoelectronics with an emphasis on memories based on the crossbar motif. First, we will discuss representative electromechanical and resistance-change memory devices based on carbon nanotube and core-shell nanowire structures, respectively. These device structures show robust switching, promising performance metrics and the potential for terabit-scale density. Second, we will review architectures being developed for circuit-level integration, hybrid crossbar/CMOS circuits and array-based systems, including experimental demonstrations of key concepts such lithography-independent, chemically coded stochastic demultipluxers. Finally, bottom-up fabrication approaches, including the opportunity for assembly of three-dimensional, vertically integrated multifunctional circuits, will be critically discussed.

KSC-2010-4545

NASA Image and Video Library

2010-09-01

CAPE CANAVERAL, Fla. -- Technicians in the Space Station Processing Facility at NASA's Kennedy Space Center in Florida, check the progress of the Payload Attach System, or PAS, as it is lifted up to the Alpha Magnetic Spectrometer, where it will be attached to the bottom of the AMS. The PAS provides a method of securely connecting the payload to the International Space Station. AMS, a state-of-the-art particle physics detector, is designed to operate as an external module on the International Space Station. It will use the unique environment of space to study the universe and its origin by searching for dark matter. AMS will fly to the station aboard space shuttle Endeavour's STS-134 mission targeted to launch Feb. 26, 2011. Photo credit: NASA/Jack Pfaller

KSC-2010-4546

NASA Image and Video Library

2010-09-01

CAPE CANAVERAL, Fla. -- In the Space Station Processing Facility at NASA's Kennedy Space Center in Florida, a technician monitors the progress of the Payload Attach System, or PAS, as it is lifted up to the Alpha Magnetic Spectrometer, or AMS, where it will be attached to the bottom of the AMS. The PAS provides a method of securely connecting the payload to the International Space Station. AMS, a state-of-the-art particle physics detector, is designed to operate as an external module on the International Space Station. It will use the unique environment of space to study the universe and its origin by searching for dark matter. AMS will fly to the station aboard space shuttle Endeavour's STS-134 mission targeted to launch Feb. 26, 2011. Photo credit: NASA/Jack Pfaller

KSC-2010-4547

NASA Image and Video Library

2010-09-01

CAPE CANAVERAL, Fla. -- A technicians in the Space Station Processing Facility at NASA's Kennedy Space Center in Florida, check the progress of the Payload Attach System, or PAS, as it is lifted up to the Alpha Magnetic Spectrometer, or AMS, where it will be attached to the bottom of the AMS. The PAS provides a method of securely connecting the payload to the International Space Station. AMS, a state-of-the-art particle physics detector, is designed to operate as an external module on the International Space Station. It will use the unique environment of space to study the universe and its origin by searching for dark matter. AMS will fly to the station aboard space shuttle Endeavour's STS-134 mission targeted to launch Feb. 26, 2011. Photo credit: NASA/Jack Pfaller

Glucose-6-phosphate dehydrogenase deficiency and the use of primaquine: top-down and bottom-up estimation of professional costs.

PubMed

Peixoto, Henry Maia; Brito, Marcelo Augusto Mota; Romero, Gustavo Adolfo Sierra; Monteiro, Wuelton Marcelo; Lacerda, Marcus Vinícius Guimarães de; Oliveira, Maria Regina Fernandes de

2017-10-05

The aim of this study has been to study whether the top-down method, based on the average value identified in the Brazilian Hospitalization System (SIH/SUS), is a good estimator of the cost of health professionals per patient, using the bottom-up method for comparison. The study has been developed from the context of hospital care offered to the patient carrier of glucose-6-phosphate dehydrogenase (G6PD) deficiency with severe adverse effect because of the use of primaquine, in the Brazilian Amazon. The top-down method based on the spending with SIH/SUS professional services, as a proxy for this cost, corresponded to R$60.71, and the bottom-up, based on the salaries of the physician (R$30.43), nurse (R$16.33), and nursing technician (R$5.93), estimated a total cost of R$52.68. The difference was only R$8.03, which shows that the amounts paid by the Hospital Inpatient Authorization (AIH) are estimates close to those obtained by the bottom-up technique for the professionals directly involved in the care.

Enhanced Photon Extraction from a Nanowire Quantum Dot Using a Bottom-Up Photonic Shell

NASA Astrophysics Data System (ADS)

Jeannin, Mathieu; Cremel, Thibault; Häyrynen, Teppo; Gregersen, Niels; Bellet-Amalric, Edith; Nogues, Gilles; Kheng, Kuntheak

2017-11-01

Semiconductor nanowires offer the possibility to grow high-quality quantum-dot heterostructures, and, in particular, CdSe quantum dots inserted in ZnSe nanowires have demonstrated the ability to emit single photons up to room temperature. In this paper, we demonstrate a bottom-up approach to fabricate a photonic fiberlike structure around such nanowire quantum dots by depositing an oxide shell using atomic-layer deposition. Simulations suggest that the intensity collected in our NA =0.6 microscope objective can be increased by a factor 7 with respect to the bare nanowire case. Combining microphotoluminescence, decay time measurements, and numerical simulations, we obtain a fourfold increase in the collected photoluminescence from the quantum dot. We show that this improvement is due to an increase of the quantum-dot emission rate and a redirection of the emitted light. Our ex situ fabrication technique allows a precise and reproducible fabrication on a large scale. Its improved extraction efficiency is compared to state-of-the-art top-down devices.

Changing the South African national antiretroviral therapy guidelines: The role of cost modelling

PubMed Central

Johnson, Leigh F.; Pillay, Yogan; Blecher, Mark; Brennan, Alana T.; Long, Lawrence; Moultrie, Harry; Sanne, Ian; Fox, Matthew P.; Rosen, Sydney

2017-01-01

Background We were tasked by the South African Department of Health to assess the cost implications to the largest ART programme in the world of adopting sets of ART guidelines issued by the World Health Organization between 2010 and 2016. Methods Using data from large South African ART clinics (n = 24,244 patients), projections of patients in need of ART, and cost data from bottom-up cost analyses, we constructed a population-level health-state transition model with 6-monthly transitions between health states depending on patients’ age, CD4 cell count/ percentage, and, for adult first-line ART, time on treatment. Findings For each set of guidelines, the modelled increase in patient numbers as a result of prevalence and uptake was substantially more than the increase resulting from additional eligibility. Under each set of guidelines, the number of people on ART was projected to increase by 31–133% over the next seven years, and cost by 84–175%, while increased eligibility led to 1–26% more patients, and 1–17% higher cost. The projected increases in treatment cost due to the 2010 and the 2015 WHO guidelines could be offset in their entirety by the introduction of cost-saving measures such as opening the drug tenders for international competition and task-shifting. Under universal treatment, annual costs of the treatment programme will decrease for the first time from 2024 onwards. Conclusions Annual budgetary requirements for ART will continue to increase in South Africa until universal treatment is taken to full scale. Model results were instrumental in changing South African ART guidelines, more than tripling the population on treatment between 2009 and 2017, and reducing the per-patient cost of treatment by 64%. PMID:29084275

METAL OXIDE NANOPARTICLES

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

FERNANDEZ-GARCIA,M.; RODGRIGUEZ, J.A.

2007-10-01

This chapter covers the fundamental science, synthesis, characterization, physicochemical properties and applications of oxide nanomaterials. Explains fundamental aspects that determine the growth and behavior of these systems, briefly examines synthetic procedures using bottom-up and top-down fabrication technologies, discusses the sophisticated experimental techniques and state of the art theory results used to characterize the physico-chemical properties of oxide solids and describe the current knowledge concerning key oxide materials with important technological applications.

Beyond Hammers and Nails: Mitigating and Verifying Greenhouse Gas Emissions

NASA Astrophysics Data System (ADS)

Gurney, Kevin Robert

2013-05-01

One of the biggest challenges to future international agreements on climate change is an independent, science-driven method of verifying reductions in greenhouse gas emissions (GHG) [Niederberger and Kimble, 2011]. The scientific community has thus far emphasized atmospheric measurements to assess changes in emissions. An alternative is direct measurement or estimation of fluxes at the source. Given the many challenges facing the approach that uses "top-down" atmospheric measurements and recent advances in "bottom-up" estimation methods, I challenge the current doctrine, which has the atmospheric measurement approach "validating" bottom-up, "good-faith" emissions estimation [Balter, 2012] or which holds that the use of bottom-up estimation is like "dieting without weighing oneself" [Nisbet and Weiss, 2010].

The generation of myricetin-nicotinamide nanococrystals by top down and bottom up technologies

NASA Astrophysics Data System (ADS)

Liu, Mingyu; Hong, Chao; Li, Guowen; Ma, Ping; Xie, Yan

2016-09-01

Myricetin-nicotinamide (MYR-NIC) nanococrystal preparation methods were developed and optimized using both top down and bottom up approaches. The grinding (top down) method successfully achieved nanococrystals, but there were some micrometer range particles and aggregation. The key consideration of the grinding technology was to control the milling time to determine a balance between the particle size and distribution. In contrast, a modified bottom up approach based on a solution method in conjunction with sonochemistry resulted in a uniform MYR-NIC nanococrystal that was confirmed by powder x-ray diffraction, scanning electron microscopy, dynamic light scattering, and differential scanning calorimeter, and the particle dissolution rate and amount were significantly greater than that of MYR-NIC cocrystal. Notably, this was a simple method without the addition of any non-solvent. We anticipate our findings will provide some guidance for future nanococrystal preparation as well as its application in both chemical and pharmaceutical area.

Recent progress in the assembly of nanodevices and van der Waals heterostructures by deterministic placement of 2D materials.

PubMed

Frisenda, Riccardo; Navarro-Moratalla, Efrén; Gant, Patricia; Pérez De Lara, David; Jarillo-Herrero, Pablo; Gorbachev, Roman V; Castellanos-Gomez, Andres

2018-01-02

Designer heterostructures can now be assembled layer-by-layer with unmatched precision thanks to the recently developed deterministic placement methods to transfer two-dimensional (2D) materials. This possibility constitutes the birth of a very active research field on the so-called van der Waals heterostructures. Moreover, these deterministic placement methods also open the door to fabricate complex devices, which would be otherwise very difficult to achieve by conventional bottom-up nanofabrication approaches, and to fabricate fully-encapsulated devices with exquisite electronic properties. The integration of 2D materials with existing technologies such as photonic and superconducting waveguides and fiber optics is another exciting possibility. Here, we review the state-of-the-art of the deterministic placement methods, describing and comparing the different alternative methods available in the literature, and we illustrate their potential to fabricate van der Waals heterostructures, to integrate 2D materials into complex devices and to fabricate artificial bilayer structures where the layers present a user-defined rotational twisting angle.

Integrated Bottom-Up and Top-Down Liquid Chromatography-Mass Spectrometry for Characterization of Recombinant Human Growth Hormone Degradation Products.

PubMed

Wang, Yu Annie; Wu, Di; Auclair, Jared R; Salisbury, Joseph P; Sarin, Richa; Tang, Yang; Mozdzierz, Nicholas J; Shah, Kartik; Zhang, Anna Fan; Wu, Shiaw-Lin; Agar, Jeffery N; Love, J Christopher; Love, Kerry R; Hancock, William S

2017-12-05

With the advent of biosimilars to the U.S. market, it is important to have better analytical tools to ensure product quality from batch to batch. In addition, the recent popularity of using a continuous process for production of biopharmaceuticals, the traditional bottom-up method, alone for product characterization and quality analysis is no longer sufficient. Bottom-up method requires large amounts of material for analysis and is labor-intensive and time-consuming. Additionally, in this analysis, digestion of the protein with enzymes such as trypsin could induce artifacts and modifications which would increase the complexity of the analysis. On the other hand, a top-down method requires a minimum amount of sample and allows for analysis of the intact protein mass and sequence generated from fragmentation within the instrument. However, fragmentation usually occurs at the N-terminal and C-terminal ends of the protein with less internal fragmentation. Herein, we combine the use of the complementary techniques, a top-down and bottom-up method, for the characterization of human growth hormone degradation products. Notably, our approach required small amounts of sample, which is a requirement due to the sample constraints of small scale manufacturing. Using this approach, we were able to characterize various protein variants, including post-translational modifications such as oxidation and deamidation, residual leader sequence, and proteolytic cleavage. Thus, we were able to highlight the complementarity of top-down and bottom-up approaches, which achieved the characterization of a wide range of product variants in samples of human growth hormone secreted from Pichia pastoris.

Assessing the Gap Between Top-down and Bottom-up Measured Methane Emissions in Indianapolis, IN.

NASA Astrophysics Data System (ADS)

Prasad, K.; Lamb, B. K.; Cambaliza, M. O. L.; Shepson, P. B.; Stirm, B. H.; Salmon, O. E.; Lavoie, T. N.; Lauvaux, T.; Ferrara, T.; Howard, T.; Edburg, S. L.; Whetstone, J. R.

2014-12-01

Releases of methane (CH4) from the natural gas supply chain in the United States account for approximately 30% of the total US CH4 emissions. However, there continues to be large questions regarding the accuracy of current emission inventories for methane emissions from natural gas usage. In this paper, we describe results from top-down and bottom-up measurements of methane emissions from the large isolated city of Indianapolis. The top-down results are based on aircraft mass balance and tower based inverse modeling methods, while the bottom-up results are based on direct component sampling at metering and regulating stations, surface enclosure measurements of surveyed pipeline leaks, and tracer/modeling methods for other urban sources. Mobile mapping of methane urban concentrations was also used to identify significant sources and to show an urban-wide low level enhancement of methane levels. The residual difference between top-down and bottom-up measured emissions is large and cannot be fully explained in terms of the uncertainties in top-down and bottom-up emission measurements and estimates. Thus, the residual appears to be, at least partly, attributed to a significant wide-spread diffusive source. Analyses are included to estimate the size and nature of this diffusive source.

Liquid-phase thermal diffusion isotope separation apparatus and method having tapered column

DOEpatents

Rutherford, William M.

1988-05-24

A thermal diffusion counterflow method and apparatus for separating isotopes in solution in which the solution is confined in a long, narrow, vertical slit which tapers from bottom to top. The variation in the width of the slit permits maintenance of a stable concentration distribution with relatively long columns, thus permitting isotopic separation superior to that obtainable in the prior art.

Liquid-phase thermal diffusion isotope separation apparatus and method having tapered column

DOEpatents

Rutherford, W.M.

1985-12-04

A thermal diffusion counterflow method and apparatus for separating isotopes in solution in which the solution is confined in a long, narrow, vertical slit which tapers from bottom to top. The variation in the width of the slit permits maintenance of a stable concentration distribution with relatively long columns, thus permitting isotopic separation superior to that obtained in the prior art.

Aluminium alloys in municipal solid waste incineration bottom ash.

PubMed

Hu, Yanjun; Rem, Peter

2009-05-01

With the increasing growth of incineration of household waste, more and more aluminium is retained in municipal solid waste incinerator bottom ash. Therefore recycling of aluminium from bottom ash becomes increasingly important. Previous research suggests that aluminium from different sources is found in different size fractions resulting in different recycling rates. The purpose of this study was to develop analytical and sampling techniques to measure the particle size distribution of individual alloys in bottom ash. In particular, cast aluminium alloys were investigated. Based on the particle size distribution it was computed how well these alloys were recovered in a typical state-of-the-art treatment plant. Assessment of the cast alloy distribution was carried out by wet physical separation processes, as well as chemical methods, X-ray fluorescence analysis and electron microprobe analysis. The results from laboratory analyses showed that cast alloys tend to concentrate in the coarser fractions and therefore are better recovered in bottom ash treatment plants.

Alternative Reproductive Tactics in the Shell-Brooding Lake Tanganyika Cichlid Neolamprologus brevis

PubMed Central

Ota, Kazutaka; Aibara, Mitsuto; Morita, Masaya; Awata, Satoshi; Hori, Michio; Kohda, Masanori

2012-01-01

Alternative reproductive tactics (ARTs) are found in several Lake Tanganyika shell-brooding cichlids. Field studies were conducted in the Wonzye population to examine reproductive ecology and ARTs in the Lake Tanganyika shell-brooding cichlid Neolamprologus brevis. We discovered that this fish occurred in both rocky- and sandy-bottom habitats, but in rocky habitats, brood-caring females exclusively occurred in shell-patches that another cichlid species created. All N. brevis of both sexes in the patches were sexually mature, whereas immature males and females with unripe eggs were found frequently in sandy-bottom habitats. Males in sandy-bottom habitats were smaller, but fed more frequently and were in better somatic condition than males in the patches. Similar tendency was found in females. This indicates that N. brevis uses different habitats depending on the stage of its life history, with migration from sandy-bottom habitats to the shell-patches for reproduction. Males in the patches exhibited different behavior patterns: floating above the patches and lying in the patches. The former was larger, more aggressive, and invested less in gonads (relative to body size) than the latter. These results accord with those of other shell-brooding Lake Tanganyika cichlids with ARTs, and they therefore suggest the presence of ARTs in N. brevis. PMID:22888463

Human body segmentation via data-driven graph cut.

PubMed

Li, Shifeng; Lu, Huchuan; Shao, Xingqing

2014-11-01

Human body segmentation is a challenging and important problem in computer vision. Existing methods usually entail a time-consuming training phase for prior knowledge learning with complex shape matching for body segmentation. In this paper, we propose a data-driven method that integrates top-down body pose information and bottom-up low-level visual cues for segmenting humans in static images within the graph cut framework. The key idea of our approach is first to exploit human kinematics to search for body part candidates via dynamic programming for high-level evidence. Then, by using the body parts classifiers, obtaining bottom-up cues of human body distribution for low-level evidence. All the evidence collected from top-down and bottom-up procedures are integrated in a graph cut framework for human body segmentation. Qualitative and quantitative experiment results demonstrate the merits of the proposed method in segmenting human bodies with arbitrary poses from cluttered backgrounds.

Postcolonial Appalachia: Bhabha, Bakhtin, and Diane Gilliam Fisher's "Kettle Bottom"

ERIC Educational Resources Information Center

Stevenson, Sheryl

2006-01-01

Diane Gilliam Fisher's 2004 award-winning book of poems, "Kettle Bottom," offers students a revealing vantage point for seeing Appalachian regional culture in a postcolonial context. An artful and accessible poetic sequence that was selected as the 2005 summer reading for entering students at Smith College, "Kettle Bottom"…

Conceptions of the temporal course of aesthetic engagement. Comment on "Move me, astonish me…" delight my eyes and brain: The Vienna Integrated Model of top-down and bottom-up processes in Art Perception (VIMAP) and corresponding affective, evaluative, and neurophysiological correlates; by Matthew Pelowski et al.

NASA Astrophysics Data System (ADS)

Kuiken, Don; Jacobs, Arthur M.

2017-07-01

Pelowski et al. [9] propose a constructive and expansive theoretical framework of response to an important section of the world of art, i.e. visual art, excluding verbal art and other forms. More than its conceptual predecessors, this framework is intended to guide investigation (1) not only of the influence of personality variations but also of the viewer's hierarchically structured self-image (ideal traits, general schemas, specific goals, action goals; p. 15); (2) not only of initial responses to low-level features but also of how those initial responses become the focus of high-level reactions (p. 7-8); and (3) not only of the sources of pleasure, interest, and appreciation but also of ;transformative; aesthetic outcomes (p. 35ff).

Hydrophobic Interaction Chromatography for Bottom-Up Proteomics Analysis of Single Proteins and Protein Complexes.

PubMed

Rackiewicz, Michal; Große-Hovest, Ludger; Alpert, Andrew J; Zarei, Mostafa; Dengjel, Jörn

2017-06-02

Hydrophobic interaction chromatography (HIC) is a robust standard analytical method to purify proteins while preserving their biological activity. It is widely used to study post-translational modifications of proteins and drug-protein interactions. In the current manuscript we employed HIC to separate proteins, followed by bottom-up LC-MS/MS experiments. We used this approach to fractionate antibody species followed by comprehensive peptide mapping as well as to study protein complexes in human cells. HIC-reversed-phase chromatography (RPC)-mass spectrometry (MS) is a powerful alternative to fractionate proteins for bottom-up proteomics experiments making use of their distinct hydrophobic properties.

Comparing top-down and bottom-up estimates of methane emissions across multiple U.S. oil and gas basins provides insights into national O&G emissions, mitigation strategies, and research priorities

NASA Astrophysics Data System (ADS)

Lyon, D. R.; Alvarez, R.; Zavala Araiza, D.; Hamburg, S.

2017-12-01

We develop a county-level inventory of U.S. anthropogenic methane emissions by integrating multiple data sources including the Drillinginfo oil and gas (O&G) production database, Environmental Protection Agency (EPA) Greenhouse Gas Reporting Program, a previously published gridded EPA Greenhouse Gas Inventory (Maasakkers et al 2016), and recent measurements studies of O&G pneumatic devices, equipment leaks, abandoned wells, and midstream facilities. Our bottom-up estimates of total and O&G methane emissions are consistently lower than top-down, aerial mass balance estimates in ten O&G production areas. We evaluate several hypotheses for the top-down/bottom-up discrepancy including potential bias of the aerial mass balance method, temporal mismatch of top-down and bottom-up emission estimates, and source attribution errors. In most basins, the top-down/bottom-up gap cannot be explained fully without additional O&G emissions from sources not included in traditional inventories, such as super-emitters caused by malfunctions or abnormal process conditions. Top-down/bottom-up differences across multiple basins are analyzed to estimate the magnitude of these additional emissions and constrain total methane emissions from the U.S. O&G supply chain. We discuss the implications for mitigating O&G methane emissions and suggest research priorities for increasing the accuracy of future emission inventories.

THEMIS Art #101

NASA Image and Video Library

2013-06-24

Do you see what I see in this image from NASA Mars Odyssey spacecraft? The connected craters at the top and bottom of this image look like bugs, perhaps a bumble bee at the top and a wasp at the bottom.

A novel method for quantitative geosteering using azimuthal gamma-ray logging.

PubMed

Yuan, Chao; Zhou, Cancan; Zhang, Feng; Hu, Song; Li, Chaoliu

2015-02-01

A novel method for quantitative geosteering by using azimuthal gamma-ray logging is proposed. Real-time up and bottom gamma-ray logs when a logging tool travels through a boundary surface with different relative dip angles are simulated with the Monte Carlo method. Study results show that response points of up and bottom gamma-ray logs when the logging tool moves towards a highly radioactive formation can be used to predict the relative dip angle, and then the distance from the drilling bit to the boundary surface is calculated. Copyright © 2014 Elsevier Ltd. All rights reserved.

Finding regions of interest in pathological images: an attentional model approach

NASA Astrophysics Data System (ADS)

Gómez, Francisco; Villalón, Julio; Gutierrez, Ricardo; Romero, Eduardo

2009-02-01

This paper introduces an automated method for finding diagnostic regions-of-interest (RoIs) in histopathological images. This method is based on the cognitive process of visual selective attention that arises during a pathologist's image examination. Specifically, it emulates the first examination phase, which consists in a coarse search for tissue structures at a "low zoom" to separate the image into relevant regions.1 The pathologist's cognitive performance depends on inherent image visual cues - bottom-up information - and on acquired clinical medicine knowledge - top-down mechanisms -. Our pathologist's visual attention model integrates the latter two components. The selected bottom-up information includes local low level features such as intensity, color, orientation and texture information. Top-down information is related to the anatomical and pathological structures known by the expert. A coarse approximation to these structures is achieved by an oversegmentation algorithm, inspired by psychological grouping theories. The algorithm parameters are learned from an expert pathologist's segmentation. Top-down and bottom-up integration is achieved by calculating a unique index for each of the low level characteristics inside the region. Relevancy is estimated as a simple average of these indexes. Finally, a binary decision rule defines whether or not a region is interesting. The method was evaluated on a set of 49 images using a perceptually-weighted evaluation criterion, finding a quality gain of 3dB when comparing to a classical bottom-up model of attention.

Why bottom-up taxonomies are unlikely to satisfy the quest for a definitive taxonomy of situations.

PubMed

Reis, Harry T

2018-03-01

The recent advent of methods for large-scale data collection has provided an unprecedented opportunity for researchers who seek to develop a taxonomy of situations. Parrigon, Woo, Tay, and Wang's (2017) CAPTIONs model is the latest such effort. In this comment, I argue that although bottom-up approaches of this sort have clear value, they are unlikely to provide the sort of definitive, comprehensive, and theoretically integrative taxonomy that the field wants and needs. In large part, this is because bottom-up taxonomies represent what is common about situations and not what is theoretically important and influential about them. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Using Top-down and Bottom-up Costing Approaches in LMICs: The Case for Using Both to Assess the Incremental Costs of New Technologies at Scale.

PubMed

Cunnama, Lucy; Sinanovic, Edina; Ramma, Lebogang; Foster, Nicola; Berrie, Leigh; Stevens, Wendy; Molapo, Sebaka; Marokane, Puleng; McCarthy, Kerrigan; Churchyard, Gavin; Vassall, Anna

2016-02-01

Estimating the incremental costs of scaling-up novel technologies in low-income and middle-income countries is a methodologically challenging and substantial empirical undertaking, in the absence of routine cost data collection. We demonstrate a best practice pragmatic approach to estimate the incremental costs of new technologies in low-income and middle-income countries, using the example of costing the scale-up of Xpert Mycobacterium tuberculosis (MTB)/resistance to riframpicin (RIF) in South Africa. We estimate costs, by applying two distinct approaches of bottom-up and top-down costing, together with an assessment of processes and capacity. The unit costs measured using the different methods of bottom-up and top-down costing, respectively, are $US16.9 and $US33.5 for Xpert MTB/RIF, and $US6.3 and $US8.5 for microscopy. The incremental cost of Xpert MTB/RIF is estimated to be between $US14.7 and $US17.7. While the average cost of Xpert MTB/RIF was higher than previous studies using standard methods, the incremental cost of Xpert MTB/RIF was found to be lower. Costs estimates are highly dependent on the method used, so an approach, which clearly identifies resource-use data collected from a bottom-up or top-down perspective, together with capacity measurement, is recommended as a pragmatic approach to capture true incremental cost where routine cost data are scarce. © 2016 The Authors. Health Economics published by John Wiley & Sons Ltd.

Oriented bottom-up growth of armchair graphene nanoribbons on germanium

DOEpatents

Arnold, Michael Scott; Jacobberger, Robert Michael

2016-03-15

Graphene nanoribbon arrays, methods of growing graphene nanoribbon arrays and electronic and photonic devices incorporating the graphene nanoribbon arrays are provided. The graphene nanoribbons in the arrays are formed using a scalable, bottom-up, chemical vapor deposition (CVD) technique in which the (001) facet of the germanium is used to orient the graphene nanoribbon crystals along the [110] directions of the germanium.

Event-Related Potentials of Bottom-Up and Top-Down Processing of Emotional Faces

PubMed Central

Moradi, Afsane; Mehrinejad, Seyed Abolghasem; Ghadiri, Mohammad; Rezaei, Farzin

2017-01-01

Introduction: Emotional stimulus is processed automatically in a bottom-up way or can be processed voluntarily in a top-down way. Imaging studies have indicated that bottom-up and top-down processing are mediated through different neural systems. However, temporal differentiation of top-down versus bottom-up processing of facial emotional expressions has remained to be clarified. The present study aimed to explore the time course of these processes as indexed by the emotion-specific P100 and late positive potential (LPP) event-related potential (ERP) components in a group of healthy women. Methods: Fourteen female students of Alzahra University, Tehran, Iran aged 18–30 years, voluntarily participated in the study. The subjects completed 2 overt and covert emotional tasks during ERP acquisition. Results: The results indicated that fearful expressions significantly produced greater P100 amplitude compared to other expressions. Moreover, the P100 findings showed an interaction between emotion and processing conditions. Further analysis indicated that within the overt condition, fearful expressions elicited more P100 amplitude compared to other emotional expressions. Also, overt conditions created significantly more LPP latencies and amplitudes compared to covert conditions. Conclusion: Based on the results, early perceptual processing of fearful face expressions is enhanced in top-down way compared to bottom-up way. It also suggests that P100 may reflect an attentional bias toward fearful emotions. However, no such differentiation was observed within later processing stages of face expressions, as indexed by the ERP LPP component, in a top-down versus bottom-up way. Overall, this study provides a basis for further exploring of bottom-up and top-down processes underlying emotion and may be typically helpful for investigating the temporal characteristics associated with impaired emotional processing in psychiatric disorders. PMID:28446947

Calculation of parameters of technological equipment for deep-sea mining

NASA Astrophysics Data System (ADS)

Yungmeister, D. A.; Ivanov, S. E.; Isaev, A. I.

2018-03-01

The actual problem of extracting minerals from the bottom of the world ocean is considered. On the ocean floor, three types of minerals are of interest: iron-manganese concretions (IMC), cobalt-manganese crusts (CMC) and sulphides. The analysis of known designs of machines and complexes for the extraction of IMC is performed. These machines are based on the principle of excavating the bottom surface; however such methods do not always correspond to “gentle” methods of mining. The ecological purity of such mining methods does not meet the necessary requirements. Such machines require the transmission of high electric power through the water column, which in some cases is a significant challenge. The authors analyzed the options of transportation of the extracted mineral from the bottom. The paper describes the design of machines that collect IMC by the method of vacuum suction. In this method, the gripping plates or drums are provided with cavities in which a vacuum is created and individual IMC are attracted to the devices by a pressure drop. The work of such machines can be called “gentle” processing technology of the bottom areas. Their environmental impact is significantly lower than mechanical devices that carry out the raking of IMC. The parameters of the device for lifting the IMC collected on the bottom are calculated. With the use of Kevlar ropes of serial production up to 0.06 meters in diameter, with a cycle time of up to 2 hours and a lifting speed of up to 3 meters per second, a productivity of about 400,000 tons per year can be realized for IMC. The development of machines based on the calculated parameters and approbation of their designs will create a unique complex for the extraction of minerals at oceanic deposits.

Representing the sublime in the VIMAP and empirical aesthetics: Reviving Edmund Burke's A Philosophical Enquiry into the Origins of Our Ideas of the Sublime and Beautiful. Comment on "Move me, astonish me... delight my eyes and brain: The Vienna Integrated Model of top-down and bottom-up processes in Art Perception (VIMAP) and corresponding affective, evaluative, and neurophysiological correlates" by Matthew Pelowski et al.

NASA Astrophysics Data System (ADS)

Hur, Y.-J.; McManus, I. C.

2017-07-01

This commentary considers the role of the sublime in the Vienna Integrated Model of Art Perception (VIMAP; Pelowski, Markey, Forster, Gerger, & Leder [17]), and suggest that it is not precisely conceptualised in the model. In part that reflects different views and usages of the sublime in the literature, and here it is recommended that Burke's [2] view of the sublime is used as a primary framework for empirical research on the sublime.

Quantifying atmospheric pollutant emissions from open biomass burning with multiple methods: a case study for Yangtze River Delta region, China

NASA Astrophysics Data System (ADS)

Yang, Y.; Zhao, Y.

2017-12-01

To understand the differences and their origins of emission inventories based on various methods for the source, emissions of PM10, PM2.5, OC, BC, CH4, VOCs, CO, CO2, NOX, SO2 and NH3 from open biomass burning (OBB) in Yangtze River Delta (YRD) are calculated for 2005-2012 using three (bottom-up, FRP-based and constraining) approaches. The inter-annual trends in emissions with FRP-based and constraining methods are similar with the fire counts in 2005-2012, while that with bottom-up method is different. For most years, emissions of all species estimated with constraining method are smaller than those with bottom-up method (except for VOCs), while they are larger than those with FRP-based (except for EC, CH4 and NH3). Such discrepancies result mainly from different masses of crop residues burned in the field (CRBF) estimated in the three methods. Among the three methods, the simulated concentrations from chemistry transport modeling with the constrained emissions are the closest to available observations, implying the result from constraining method is the best estimation for OBB emissions. CO emissions in the three methods are compared with other studies. Similar temporal variations were found for the constrained emissions, FRP-based emissions, GFASv1.0 and GFEDv4.1s, with the largest and the lowest emissions estimated for 2012 and 2006, respectively. The constrained CO emissions in this study are smaller than those in other studies based on bottom-up method and larger than those based on burned area and FRP derived from satellite. The contributions of OBB to two particulate pollution events in 2010 and 2012 are analyzed with the brute-force method. The average contribution of OBB to PM10 mass concentrations in June 8-14 2012 was estimated at 38.9% (74.8 μg m-3), larger than that in June 17-24, 2010 at 23.6 % (38.5 μg m-3). Influences of diurnal curves and meteorology on air pollution caused by OBB are also evaluated, and the results suggest that air pollution caused by OBB will become heavier if the meteorological conditions are unfavorable, and that more attention should be paid to the supervision in night. Quantified with the Monte-Carlo simulation, the uncertainties of OBB emissions with constraining method are significantly lower than those with bottom-up or FRP-based methods.

Methods, Tools, and Data for Coastal System Resilience Assessments

DTIC Science & Technology

2015-10-06

Baseline Resilience Indicators for Communities ( BRIC ) BUILDING STRONG® Innovative solutions for a safer, better world ► T: SoVI® – Social...address policy  Objective, although data may be arbitrarily weighted in an index Examples: Top-Down (T) and Bottom-Up (B) Bottom-UpTop-Down BRIC ...Coastal Resilience Index USACE’s Resilience Matrix ASCE’s Infrastructure Report Card T: Baseline Resilience Index for Communities ( BRIC

Nanoscale device architectures derived from biological assemblies: The case of tobacco mosaic virus and (apo)ferritin

NASA Astrophysics Data System (ADS)

Calò, Annalisa; Eiben, Sabine; Okuda, Mitsuhiro; Bittner, Alexander M.

2016-03-01

Virus particles and proteins are excellent examples of naturally occurring structures with well-defined nanoscale architectures, for example, cages and tubes. These structures can be employed in a bottom-up assembly strategy to fabricate repetitive patterns of hybrid organic-inorganic materials. In this paper, we review methods of assembly that make use of protein and virus scaffolds to fabricate patterned nanostructures with very high spatial control. We chose (apo)ferritin and tobacco mosaic virus (TMV) as model examples that have already been applied successfully in nanobiotechnology. Their interior space and their exterior surfaces can be mineralized with inorganic layers or nanoparticles. Furthermore, their native assembly abilities can be exploited to generate periodic architectures for integration in electrical and magnetic devices. We introduce the state of the art and describe recent advances in biomineralization techniques, patterning and device production with (apo)ferritin and TMV.

State of the art of nanocrystals technology for delivery of poorly soluble drugs

NASA Astrophysics Data System (ADS)

Zhou, Yuqi; Du, Juan; Wang, Lulu; Wang, Yancai

2016-09-01

Formulation of nanocrystals is a distinctive approach which can effectively improve the delivery of poorly water-soluble drugs, thus enticing the development of the nanocrystals technology. The characteristics of nanocrystals resulted in an exceptional drug delivery conductance, including saturation solubility, dissolution velocity, adhesiveness, and affinity. Nanocrystals were treated as versatile pharmaceuticals that could be delivered through almost all routes of administration. In the current review, oral, pulmonary, and intravenous routes of administration were presented. Also, the targeting of drug nanocrystals, as well as issues of efficacy and safety, were also discussed. Several methods were applied for nanocrystals production including top-down production strategy (media milling, high-pressure homogenization), bottom-up production strategy (antisolvent precipitation, supercritical fluid process, and precipitation by removal of solvent), and the combination approaches. Moreover, this review also described the evaluation and characterization of the drug nanocrystals and summarized the current commercial pharmaceutical products utilizing nanocrystals technology.

Cognitive functions of the posterior parietal cortex: top-down and bottom-up attentional control

PubMed Central

Shomstein, Sarah

2012-01-01

Although much less is known about human parietal cortex than that of homologous monkey cortex, recent studies, employing neuroimaging, and neuropsychological methods, have begun to elucidate increasingly fine-grained functional and structural distinctions. This review is focused on recent neuroimaging and neuropsychological studies elucidating the cognitive roles of dorsal and ventral regions of parietal cortex in top-down and bottom-up attentional orienting, and on the interaction between the two attentional allocation mechanisms. Evidence is reviewed arguing that regions along the dorsal areas of the parietal cortex, including the superior parietal lobule (SPL) are involved in top-down attentional orienting, while ventral regions including the temporo-parietal junction (TPJ) are involved in bottom-up attentional orienting. PMID:22783174

On the complex interaction between mathematics and the sciences of living systems. Comment on "Move me, astonish me...delight my eyes and brain: The Vienna Integrated Model of top-down and bottom-up processes in Art Perception (VIMAP) and corresponding affective, evaluative, and neurophysiological correlates" by Matthew Pelowski et al.

NASA Astrophysics Data System (ADS)

Bellomo, Nicola; Outada, Nisrine

2017-07-01

Cultural framework: Our comment looks at the general framework given by the interactions between the so-called ;soft; and ;hard; sciences. Specifically, it looks at the development of a mathematics for living systems. Our comment aims at showing how the interesting survey [11] can contribute to the aforementioned challenging task.

Beauty and sublime. Comment on "Move me, astonish me…" delight my eyes and brain: The Vienna Integrated Model of top-down and bottom-up processes in Art Perception (VIMAP) and corresponding affective, evaluative, and neurophysiological correlates; by Matthew Pelowski et al.

NASA Astrophysics Data System (ADS)

Perlovsky, Leonid

2017-07-01

The VIMAP model presented in this review [1] is an interesting and detailed model of neural mechanisms of aesthetic perception. In this Comment I address one deficiency of this model: it does not address in details the fundamental notions of the VIMAP, beauty and sublime. In this regard VIMAP is similar to other publications on aesthetics.

A model of proto-object based saliency

PubMed Central

Russell, Alexander F.; Mihalaş, Stefan; von der Heydt, Rudiger; Niebur, Ernst; Etienne-Cummings, Ralph

2013-01-01

Organisms use the process of selective attention to optimally allocate their computational resources to the instantaneously most relevant subsets of a visual scene, ensuring that they can parse the scene in real time. Many models of bottom-up attentional selection assume that elementary image features, like intensity, color and orientation, attract attention. Gestalt psychologists, how-ever, argue that humans perceive whole objects before they analyze individual features. This is supported by recent psychophysical studies that show that objects predict eye-fixations better than features. In this report we present a neurally inspired algorithm of object based, bottom-up attention. The model rivals the performance of state of the art non-biologically plausible feature based algorithms (and outperforms biologically plausible feature based algorithms) in its ability to predict perceptual saliency (eye fixations and subjective interest points) in natural scenes. The model achieves this by computing saliency as a function of proto-objects that establish the perceptual organization of the scene. All computational mechanisms of the algorithm have direct neural correlates, and our results provide evidence for the interface theory of attention. PMID:24184601

C-STrap Sample Preparation Method--In-Situ Cysteinyl Peptide Capture for Bottom-Up Proteomics Analysis in the STrap Format.

PubMed

Zougman, Alexandre; Banks, Rosamonde E

2015-01-01

Recently we introduced the concept of Suspension Trapping (STrap) for bottom-up proteomics sample processing that is based upon SDS-mediated protein extraction, swift detergent removal and rapid reactor-type protein digestion in a quartz depth filter trap. As the depth filter surface is made of silica, it is readily modifiable with various functional groups using the silane coupling chemistries. Thus, during the digest, peptides possessing specific features could be targeted for enrichment by the functionalized depth filter material while non-targeted peptides could be collected as an unbound distinct fraction after the digest. In the example presented here the quartz depth filter surface is functionalized with the pyridyldithiol group therefore enabling reversible in-situ capture of the cysteine-containing peptides generated during the STrap-based digest. The described C-STrap method retains all advantages of the original STrap methodology and provides robust foundation for the conception of the targeted in-situ peptide fractionation in the STrap format for bottom-up proteomics. The presented data support the method's use in qualitative and semi-quantitative proteomics experiments.

Structural and material approaches to bone tissue engineering in powder-based three-dimensional printing.

PubMed

Butscher, A; Bohner, M; Hofmann, S; Gauckler, L; Müller, R

2011-03-01

This article reviews the current state of knowledge concerning the use of powder-based three-dimensional printing (3DP) for the synthesis of bone tissue engineering scaffolds. 3DP is a solid free-form fabrication (SFF) technique building up complex open porous 3D structures layer by layer (a bottom-up approach). In contrast to traditional fabrication techniques generally subtracting material step by step (a top-down approach), SFF approaches allow nearly unlimited designs and a large variety of materials to be used for scaffold engineering. Today's state of the art materials, as well as the mechanical and structural requirements for bone scaffolds, are summarized and discussed in relation to the technical feasibility of their use in 3DP. Advances in the field of 3DP are presented and compared with other SFF methods. Existing strategies on material and design control of scaffolds are reviewed. Finally, the possibilities and limiting factors are addressed and potential strategies to improve 3DP for scaffold engineering are proposed. Copyright © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Spectral saliency via automatic adaptive amplitude spectrum analysis

NASA Astrophysics Data System (ADS)

Wang, Xiaodong; Dai, Jialun; Zhu, Yafei; Zheng, Haiyong; Qiao, Xiaoyan

2016-03-01

Suppressing nonsalient patterns by smoothing the amplitude spectrum at an appropriate scale has been shown to effectively detect the visual saliency in the frequency domain. Different filter scales are required for different types of salient objects. We observe that the optimal scale for smoothing amplitude spectrum shares a specific relation with the size of the salient region. Based on this observation and the bottom-up saliency detection characterized by spectrum scale-space analysis for natural images, we propose to detect visual saliency, especially with salient objects of different sizes and locations via automatic adaptive amplitude spectrum analysis. We not only provide a new criterion for automatic optimal scale selection but also reserve the saliency maps corresponding to different salient objects with meaningful saliency information by adaptive weighted combination. The performance of quantitative and qualitative comparisons is evaluated by three different kinds of metrics on the four most widely used datasets and one up-to-date large-scale dataset. The experimental results validate that our method outperforms the existing state-of-the-art saliency models for predicting human eye fixations in terms of accuracy and robustness.

Deep convolutional networks for pancreas segmentation in CT imaging

NASA Astrophysics Data System (ADS)

Roth, Holger R.; Farag, Amal; Lu, Le; Turkbey, Evrim B.; Summers, Ronald M.

2015-03-01

Automatic organ segmentation is an important prerequisite for many computer-aided diagnosis systems. The high anatomical variability of organs in the abdomen, such as the pancreas, prevents many segmentation methods from achieving high accuracies when compared to state-of-the-art segmentation of organs like the liver, heart or kidneys. Recently, the availability of large annotated training sets and the accessibility of affordable parallel computing resources via GPUs have made it feasible for "deep learning" methods such as convolutional networks (ConvNets) to succeed in image classification tasks. These methods have the advantage that used classification features are trained directly from the imaging data. We present a fully-automated bottom-up method for pancreas segmentation in computed tomography (CT) images of the abdomen. The method is based on hierarchical coarse-to-fine classification of local image regions (superpixels). Superpixels are extracted from the abdominal region using Simple Linear Iterative Clustering (SLIC). An initial probability response map is generated, using patch-level confidences and a two-level cascade of random forest classifiers, from which superpixel regions with probabilities larger 0.5 are retained. These retained superpixels serve as a highly sensitive initial input of the pancreas and its surroundings to a ConvNet that samples a bounding box around each superpixel at different scales (and random non-rigid deformations at training time) in order to assign a more distinct probability of each superpixel region being pancreas or not. We evaluate our method on CT images of 82 patients (60 for training, 2 for validation, and 20 for testing). Using ConvNets we achieve maximum Dice scores of an average 68% +/- 10% (range, 43-80%) in testing. This shows promise for accurate pancreas segmentation, using a deep learning approach and compares favorably to state-of-the-art methods.

Top-down and bottom-up lipidomic analysis of rabbit lipoproteins under different metabolic conditions using flow field-flow fractionation, nanoflow liquid chromatography and mass spectrometry.

PubMed

Byeon, Seul Kee; Kim, Jin Yong; Lee, Ju Yong; Chung, Bong Chul; Seo, Hong Seog; Moon, Myeong Hee

2015-07-31

This study demonstrated the performances of top-down and bottom-up approaches in lipidomic analysis of lipoproteins from rabbits raised under different metabolic conditions: healthy controls, carrageenan-induced inflammation, dehydration, high cholesterol (HC) diet, and highest cholesterol diet with inflammation (HCI). In the bottom-up approach, the high density lipoproteins (HDL) and the low density lipoproteins (LDL) were size-sorted and collected on a semi-preparative scale using a multiplexed hollow fiber flow field-flow fractionation (MxHF5), followed by nanoflow liquid chromatography-ESI-MS/MS (nLC-ESI-MS/MS) analysis of the lipids extracted from each lipoprotein fraction. In the top-down method, size-fractionated lipoproteins were directly infused to MS for quantitative analysis of targeted lipids using chip-type asymmetrical flow field-flow fractionation-electrospray ionization-tandem mass spectrometry (cAF4-ESI-MS/MS) in selected reaction monitoring (SRM) mode. The comprehensive bottom-up analysis yielded 122 and 104 lipids from HDL and LDL, respectively. Rabbits within the HC and HCI groups had lipid patterns that contrasted most substantially from those of controls, suggesting that HC diet significantly alters the lipid composition of lipoproteins. Among the identified lipids, 20 lipid species that exhibited large differences (>10-fold) were selected as targets for the top-down quantitative analysis in order to compare the results with those from the bottom-up method. Statistical comparison of the results from the two methods revealed that the results were not significantly different for most of the selected species, except for those species with only small differences in concentration between groups. The current study demonstrated that top-down lipid analysis using cAF4-ESI-MS/MS is a powerful high-speed analytical platform for targeted lipidomic analysis that does not require the extraction of lipids from blood samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Developing a Comprehensive and Comparative Questionnaire for Measuring Personality in Chimpanzees Using a Simultaneous Top-Down/Bottom-Up Design

PubMed Central

Freeman, Hani D.; Brosnan, Sarah F.; Hopper, Lydia M.; Lambeth, Susan P.; Schapiro, Steven J.; Gosling, Samuel D.

2013-01-01

One effective method for measuring personality in primates is to use personality trait ratings to distill the experience of people familiar with the individual animals. Previous rating instruments were created using either top-down or bottom-up approaches. Top-down approaches, which essentially adapt instruments originally designed for use with another species, can unfortunately lead to the inclusion of traits irrelevant to chimpanzees or fail to include all relevant aspects of chimpanzee personality. Conversely, because bottom-up approaches derive traits specifically for chimpanzees, their unique items may impede comparisons with findings in other studies and other species. To address the limitations of each approach, we developed a new personality rating scale using a combined top-down/bottom-up design. Seventeen raters rated 99 chimpanzees on the new 41-item scale, with all but one item being rated reliably. Principal components analysis, using both varimax and direct oblimin rotations, identified six broad factors. Strong evidence was found for five of the factors (Reactivity/Undependability, Dominance, Openness, Extraversion, and Agreeableness). A sixth factor (Methodical) was offered provisionally until more data are collected. We validated the factors against behavioral data collected independently on the chimpanzees. The five factors demonstrated good evidence for convergent and predictive validity, thereby underscoring the robustness of the factors. Our combined top-down/ bottom-up approach provides the most extensive data to date to support the universal existence of these five personality factors in chimpanzees. This framework, which facilitates cross-species comparisons, can also play a vital role in understanding the evolution of personality and can assist with husbandry and welfare efforts. PMID:23733359

Implementation of Non-Destructive Evaluation and Process Monitoring in DLP-based Additive Manufacturing

NASA Astrophysics Data System (ADS)

Kovalenko, Iaroslav; Verron, Sylvain; Garan, Maryna; Šafka, Jiří; Moučka, Michal

2017-04-01

This article describes a method of in-situ process monitoring in the digital light processing (DLP) 3D printer. It is based on the continuous measurement of the adhesion force between printing surface and bottom of a liquid resin bath. This method is suitable only for the bottom-up DPL printers. Control system compares the force at the moment of unsticking of printed layer from the bottom of the tank, when it has the largest value in printing cycle, with theoretical value. Implementation of suggested algorithm can make detection of faults during the printing process possible.

Agricultural ammonia emissions in China: reconciling bottom-up and top-down estimates

NASA Astrophysics Data System (ADS)

Zhang, Lin; Chen, Youfan; Zhao, Yuanhong; Henze, Daven K.; Zhu, Liye; Song, Yu; Paulot, Fabien; Liu, Xuejun; Pan, Yuepeng; Lin, Yi; Huang, Binxiang

2018-01-01

Current estimates of agricultural ammonia (NH3) emissions in China differ by more than a factor of 2, hindering our understanding of their environmental consequences. Here we apply both bottom-up statistical and top-down inversion methods to quantify NH3 emissions from agriculture in China for the year 2008. We first assimilate satellite observations of NH3 column concentration from the Tropospheric Emission Spectrometer (TES) using the GEOS-Chem adjoint model to optimize Chinese anthropogenic NH3 emissions at the 1/2° × 2/3° horizontal resolution for March-October 2008. Optimized emissions show a strong summer peak, with emissions about 50 % higher in summer than spring and fall, which is underestimated in current bottom-up NH3 emission estimates. To reconcile the latter with the top-down results, we revisit the processes of agricultural NH3 emissions and develop an improved bottom-up inventory of Chinese NH3 emissions from fertilizer application and livestock waste at the 1/2° × 2/3° resolution. Our bottom-up emission inventory includes more detailed information on crop-specific fertilizer application practices and better accounts for meteorological modulation of NH3 emission factors in China. We find that annual anthropogenic NH3 emissions are 11.7 Tg for 2008, with 5.05 Tg from fertilizer application and 5.31 Tg from livestock waste. The two sources together account for 88 % of total anthropogenic NH3 emissions in China. Our bottom-up emission estimates also show a distinct seasonality peaking in summer, consistent with top-down results from the satellite-based inversion. Further evaluations using surface network measurements show that the model driven by our bottom-up emissions reproduces the observed spatial and seasonal variations of NH3 gas concentrations and ammonium (NH4+) wet deposition fluxes over China well, providing additional credibility to the improvements we have made to our agricultural NH3 emission inventory.

A fusion of top-down and bottom-up modeling techniques to constrain regional scale carbon budgets

NASA Astrophysics Data System (ADS)

Goeckede, M.; Turner, D. P.; Michalak, A. M.; Vickers, D.; Law, B. E.

2009-12-01

The effort to constrain regional scale carbon budgets benefits from assimilating as many high quality data sources as possible in order to reduce uncertainties. Two of the most common approaches used in this field, bottom-up and top-down techniques, both have their strengths and weaknesses, and partly build on very different sources of information to train, drive, and validate the models. Within the context of the ORCA2 project, we follow both bottom-up and top-down modeling strategies with the ultimate objective of reconciling their surface flux estimates. The ORCA2 top-down component builds on a coupled WRF-STILT transport module that resolves the footprint function of a CO2 concentration measurement in high temporal and spatial resolution. Datasets involved in the current setup comprise GDAS meteorology, remote sensing products, VULCAN fossil fuel inventories, boundary conditions from CarbonTracker, and high-accuracy time series of atmospheric CO2 concentrations. Surface fluxes of CO2 are normally provided through a simple diagnostic model which is optimized against atmospheric observations. For the present study, we replaced the simple model with fluxes generated by an advanced bottom-up process model, Biome-BGC, which uses state-of-the-art algorithms to resolve plant-physiological processes, and 'grow' a biosphere based on biogeochemical conditions and climate history. This approach provides a more realistic description of biomass and nutrient pools than is the case for the simple model. The process model ingests various remote sensing data sources as well as high-resolution reanalysis meteorology, and can be trained against biometric inventories and eddy-covariance data. Linking the bottom-up flux fields to the atmospheric CO2 concentrations through the transport module allows evaluating the spatial representativeness of the BGC flux fields, and in that way assimilates more of the available information than either of the individual modeling techniques alone. Bayesian inversion is then applied to assign scaling factors that align the surface fluxes with the CO2 time series. Our project demonstrates how bottom-up and top-down techniques can be reconciled to arrive at a more robust and balanced spatial carbon budget. We will show how to evaluate existing flux products through regionally representative atmospheric observations, i.e. how well the underlying model assumptions represent processes on the regional scale. Adapting process model parameterizations sets for e.g. sub-regions, disturbance regimes, or land cover classes, in order to optimize the agreement between surface fluxes and atmospheric observations can lead to improved understanding of the underlying flux mechanisms, and reduces uncertainties in the regional carbon budgets.

Computer-aided design of nano-filter construction using DNA self-assembly

NASA Astrophysics Data System (ADS)

Mohammadzadegan, Reza; Mohabatkar, Hassan

2007-01-01

Computer-aided design plays a fundamental role in both top-down and bottom-up nano-system fabrication. This paper presents a bottom-up nano-filter patterning process based on DNA self-assembly. In this study we designed a new method to construct fully designed nano-filters with the pores between 5 nm and 9 nm in diameter. Our calculations illustrated that by constructing such a nano-filter we would be able to separate many molecules.

Factors controlling bacteria and protists in selected Mazurian eutrophic lakes (North-Eastern Poland) during spring

PubMed Central

2013-01-01

Background The bottom-up (food resources) and top-down (grazing pressure) controls, with other environmental parameters (water temperature, pH) are the main factors regulating the abundance and structure of microbial communities in aquatic ecosystems. It is still not definitively decided which of the two control mechanisms is more important. The significance of bottom-up versus top-down controls may alter with lake productivity and season. In oligo- and/or mesotrophic environments, the bottom-up control is mostly important in regulating bacterial abundances, while in eutrophic systems, the top-down control may be more significant. Results The abundance of bacteria, heterotrophic (HNF) and autotrophic (ANF) nanoflagellates and ciliates, as well as bacterial production (BP) and metabolically active cells of bacteria (CTC, NuCC, EST) were studied in eutrophic lakes (Mazurian Lake District, Poland) during spring. The studied lakes were characterized by high nanoflagellate (mean 17.36 ± 8.57 × 103 cells ml-1) and ciliate abundances (mean 59.9 ± 22.4 ind. ml-1) that were higher in the euphotic zone than in the bottom waters, with relatively low bacterial densities (4.76 ± 2.08 × 106 cells ml-1) that were lower in the euphotic zone compared to the profundal zone. Oligotrichida (Rimostrombidium spp.), Prostomatida (Urotricha spp.) and Scuticociliatida (Histiobalantium bodamicum) dominated in the euphotic zone, whereas oligotrichs Tintinnidium sp. and prostomatids Urotricha spp. were most numerous in the bottom waters. Among the staining methods used to examine bacterial cellular metabolic activity, the lowest percentage of active cells was recorded with the CTC (1.5–15.4%) and EST (2.7–14.2%) assay in contrast to the NuCC (28.8–97.3%) method. Conclusions In the euphotic zone, the bottom-up factors (TP and DOC concentrations) played a more important role than top-down control (grazing by protists) in regulating bacterial numbers and activity. None of the single analyzed factors controlled bacterial abundance in the bottom waters. The results of this study suggest that both control mechanisms, bottom-up and top-down, simultaneously regulated bacterial community and their activity in the profundal zone of the studied lakes during spring. In both lake water layers, food availability (algae, nanoflagellates) was probably the major factor determining ciliate abundance and their composition. In the bottom waters, both groups of protists appeared to be also influenced by oxygen, temperature, and total phosphorus. PMID:23566491

Determination of thermal wave reflection coefficient to better estimate defect depth using pulsed thermography

NASA Astrophysics Data System (ADS)

Sirikham, Adisorn; Zhao, Yifan; Mehnen, Jörn

2017-11-01

Thermography is a promising method for detecting subsurface defects, but accurate measurement of defect depth is still a big challenge because thermographic signals are typically corrupted by imaging noise and affected by 3D heat conduction. Existing methods based on numerical models are susceptible to signal noise and methods based on analytical models require rigorous assumptions that usually cannot be satisfied in practical applications. This paper presents a new method to improve the measurement accuracy of subsurface defect depth through determining the thermal wave reflection coefficient directly from observed data that is usually assumed to be pre-known. This target is achieved through introducing a new heat transfer model that includes multiple physical parameters to better describe the observed thermal behaviour in pulsed thermographic inspection. Numerical simulations are used to evaluate the performance of the proposed method against four selected state-of-the-art methods. Results show that the accuracy of depth measurement has been improved up to 10% when noise level is high and thermal wave reflection coefficients is low. The feasibility of the proposed method in real data is also validated through a case study on characterising flat-bottom holes in carbon fibre reinforced polymer (CFRP) laminates which has a wide application in various sectors of industry.

Using concept mapping to explore why patients become lost to follow up from an antiretroviral therapy program in the Zomba District of Malawi

PubMed Central

2013-01-01

Background Retention in antiretroviral therapy (ART) programmes remains a challenge in many settings including Malawi, in part due to high numbers of losses to follow-up. Concept Mapping (CM), a mix-method participatory approach, was used to explore why patients on ART are lost to follow-up (LTFU) by identifying: 1) factors that influence patient losses to follow-up and 2) barriers to effective and efficient tracing in Zomba, Malawi. Methods CM sessions (brainstorming, sorting and rating, interpretation) were conducted in urban and rural settings in Zomba, Malawi. Participants included ART patients, ART providers, Health Surveillance Assistants, and health managers from the Zomba District Health Office. In brainstorming, participants generated statements in response to “A specific reason why an individual on ART becomes lost to follow-up is…” Participants then sorted and rated the consolidated list of brainstormed items. Analysis included inductive qualitative methods for grouping of data and quantitative cluster identification to produce visual maps which were then interpreted by participants. Results In total, 90 individuals brainstormed 371 statements, 64 consolidated statements were sorted (participant n = 46), and rated on importance and feasibility (participant n = 69). A nine-cluster concept map was generated and included both patient- and healthcare-related clusters such as: Stigma and Fears, Beliefs, Acceptance and Knowledge of ART, Access to ART, Poor Documentation, Social and Financial Support Issues, Health Worker Attitudes, Resources Needed for Effective Tracing, and Health Worker Issues Related to Tracing. Strategies to respond to the clusters were generated in Interpretation. Conclusions Multiple patient- and healthcare focused factors influence why patients become LTFU. Findings have implications particularly for programs with limited resources struggling with the retention of ART patients. PMID:23758879

Top-down and bottom-up definitions of human failure events in human reliability analysis

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

Boring, Ronald Laurids

2014-10-01

In the probabilistic risk assessments (PRAs) used in the nuclear industry, human failure events (HFEs) are determined as a subset of hardware failures, namely those hardware failures that could be triggered by human action or inaction. This approach is top-down, starting with hardware faults and deducing human contributions to those faults. Elsewhere, more traditionally human factors driven approaches would tend to look at opportunities for human errors first in a task analysis and then identify which of those errors is risk significant. The intersection of top-down and bottom-up approaches to defining HFEs has not been carefully studied. Ideally, both approachesmore » should arrive at the same set of HFEs. This question is crucial, however, as human reliability analysis (HRA) methods are generalized to new domains like oil and gas. The HFEs used in nuclear PRAs tend to be top-down—defined as a subset of the PRA—whereas the HFEs used in petroleum quantitative risk assessments (QRAs) often tend to be bottom-up—derived from a task analysis conducted by human factors experts. The marriage of these approaches is necessary in order to ensure that HRA methods developed for top-down HFEs are also sufficient for bottom-up applications.« less

Seven perspectives on GPCR H/D-exchange proteomics methods

PubMed Central

Zhang, Xi

2017-01-01

Recent research shows surging interest to visualize human G protein-coupled receptor (GPCR) dynamic structures using the bottom-up H/D-exchange (HDX) proteomics technology. This opinion article clarifies critical technical nuances and logical thinking behind the GPCR HDX proteomics method, to help scientists overcome cross-discipline pitfalls, and understand and reproduce the protocol at high quality. The 2010 89% HDX structural coverage of GPCR was achieved with both structural and analytical rigor. This article emphasizes systematically considering membrane protein structure stability and compatibility with chromatography and mass spectrometry (MS) throughout the pipeline, including the effects of metal ions, zero-detergent shock, and freeze-thaws on HDX result rigor. This article proposes to view bottom-up HDX as two steps to guide choices of detergent buffers and chromatography settings: (I) protein HDX labeling in native buffers, and (II) peptide-centric analysis of HDX labels, which applies (a) bottom-up MS/MS to construct peptide matrix and (b) HDX MS to locate and quantify H/D labels. The detergent-low-TCEP digestion method demystified the challenge of HDX-grade GPCR digestion. GPCR HDX proteomics is a structural approach, thus its choice of experimental conditions should let structure lead and digestion follow, not the opposite. PMID:28529698

Bottom-up heating method for producing polyethylene lunar concrete in lunar environment

NASA Astrophysics Data System (ADS)

Lee, Jaeho; Ann, Ki Yong; Lee, Tai Sik; Mitikie, Bahiru Bewket

2018-07-01

The Apollo Program launched numerous missions to the Moon, Earth's nearest and only natural satellite. NASA is now planning new Moon missions as a first step toward human exploration of Mars and other planets. However, the Moon has an extreme environment for humans. In-situ resource utilization (ISRU) construction must be used on the Moon to build habitable structures. Previous studies on polymeric lunar concrete investigated top-down heating for stabilizing the surface. This study investigates bottom-up heating with manufacturing temperatures as low as 200 °C in a vacuum chamber that simulates the lunar environment. A maximum compressive strength of 5.7 MPa is attained; this is suitable for constructing habitable structures. Furthermore, the bottom-up heating approach achieves solidification two times faster than does the top-down heating approach.

Arts Education as a Vehicle for Social Change: An Empirical Study of Eco Arts in the K-12 Classroom

ERIC Educational Resources Information Center

Sams, Jeniffer; Sams, Doreen

2017-01-01

Arts education has been part of the United States K-12 educational system for over a century. However, recent administrative policy decisions addressed the economic bottom line and the 1983 report, "A Nation at Risk," and complied with the "No Child Left Behind (NCLB) Act of 2001" (U.S. Department of Education, 2001). These…

One Size Does Not Fit All: Human Failure Event Decomposition and Task Analysis

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

Ronald Laurids Boring, PhD

2014-09-01

In the probabilistic safety assessments (PSAs) used in the nuclear industry, human failure events (HFEs) are determined as a subset of hardware failures, namely those hardware failures that could be triggered or exacerbated by human action or inaction. This approach is top-down, starting with hardware faults and deducing human contributions to those faults. Elsewhere, more traditionally human factors driven approaches would tend to look at opportunities for human errors first in a task analysis and then identify which of those errors is risk significant. The intersection of top-down and bottom-up approaches to defining HFEs has not been carefully studied. Ideally,more » both approaches should arrive at the same set of HFEs. This question remains central as human reliability analysis (HRA) methods are generalized to new domains like oil and gas. The HFEs used in nuclear PSAs tend to be top-down—defined as a subset of the PSA—whereas the HFEs used in petroleum quantitative risk assessments (QRAs) are more likely to be bottom-up—derived from a task analysis conducted by human factors experts. The marriage of these approaches is necessary in order to ensure that HRA methods developed for top-down HFEs are also sufficient for bottom-up applications. In this paper, I first review top-down and bottom-up approaches for defining HFEs and then present a seven-step guideline to ensure a task analysis completed as part of human error identification decomposes to a level suitable for use as HFEs. This guideline illustrates an effective way to bridge the bottom-up approach with top-down requirements.« less

Adherence to antiretroviral treatment in HIV-positive patients in the Cameroon context: promoting the use of medication reminder methods.

PubMed

Roux, Perrine; Kouanfack, Charles; Cohen, Julien; Marcellin, Fabienne; Boyer, Sylvie; Delaporte, Eric; Carrieri, Patrizia; Laurent, Christian; Spire, Bruno

2011-07-01

Antiretroviral treatment (ART) scale-up in sub-Saharan Africa has made it possible to investigate the maintenance of adherence to HIV medications. We describe here adherence to ART and identify its correlates in the Cameroonian context. Prospective cohort study in 9 rural district hospitals. A mixed logistic regression model was used to identify factors associated with adherence to ART in 401 patients with data prospectively collected on adherence. Although 73% of patients were adherent after the first month on ART, this proportion decreased to 61% after 24 months. After adjustment for known factors of adherence to ART (such as knowledge, motivation and side-effects), patients who reported willingness to start ART before initiation, those who were satisfied with information provided by their physicians, and those who implemented reminder methods for ART intake {eg, using an alarm clock, mobile phone, or watch [odds ratio (95% confidence interval)] = 2.45 (1.58 to 3.79), but also the help of a relative to remind them or other methods} were more likely to be adherent to ART. Besides highlighting some correlates already known to have an impact on adherence to ART, our findings also underline the need to reinforce the counseling component of follow-up through innovative methods. Accordingly, training and implementation research should encourage the use of medication reminder methods, such as mobile phones, to assure adherence over time and improve long-term response to ART.

Perception of emotion in abstract artworks: a multidisciplinary approach.

PubMed

Melcher, David; Bacci, Francesca

2013-01-01

There is a long-standing and fundamental debate regarding how emotion can be expressed by fine art. Some artists and theorists have claimed that certain features of paintings, such as color, line, form, and composition, can consistently express an "objective" emotion, while others have argued that emotion perception is subjective and depends more on expertise of the observer. Here, we discuss two studies in which we have found evidence for consistency in observer ratings of emotion for abstract artworks. We have developed a stimulus set of abstract art images to test emotional priming, both between different painting images and between paintings and faces. The ratings were also used in a computational vision analysis of the visual features underlying emotion expression. Overall, these findings suggest that there is a strong bottom-up and objective aspect to perception of emotion in abstract artworks that may tap into basic visual mechanisms. © 2013 Elsevier B.V. All rights reserved.

Barriers to ART adherence & follow ups among patients attending ART centres in Maharashtra, India.

PubMed

Joglekar, N; Paranjape, R; Jain, R; Rahane, G; Potdar, R; Reddy, K S; Sahay, S

2011-12-01

Adherence to ART is a patient specific issue influenced by a variety of situations that a patient may encounter, especially in resource-limited settings. A study was conducted to understand factors and influencers of adherence to ART and their follow ups among patients attending ART centres in Maharashtra, India. Between January and March 2009, barriers to ART adherence among 32 patients at three selected ART centres functioning under national ART roll-out programme in Maharashtra, India, were studied using qualitative methods. Consenting patients were interviewed to assess barriers to ART adherence. Constant comparison method was used to identify grounded codes. Patients reported multiple barriers to ART adherence and follow up as (i) Financial barriers where the contributing factors were unemployment, economic dependency, and debt, (ii) social norm of attending family rituals, and fulfilling social obligations emerged as socio-cultural barriers, (iii) patients' belief, attitude and behaviour towards medication and self-perceived stigma were the reasons for sub-optimal adherence, and (iv) long waiting period, doctor-patient relationship and less time devoted in counselling at the center contributed to missed visits. Mainstreaming ART can facilitate access and address 'missed doses' due to travel and migration. A 'morning' and 'evening' ART centre/s hours may reduce work absenteeism and help in time management. Proactive 'adherence probing' and probing on internalized stigma might optimize adherence. Adherence probing to prevent transitioning to suboptimal adherence among patients stable on ART is recommended.

Visual Attention Model Based on Statistical Properties of Neuron Responses

PubMed Central

Duan, Haibin; Wang, Xiaohua

2015-01-01

Visual attention is a mechanism of the visual system that can select relevant objects from a specific scene. Interactions among neurons in multiple cortical areas are considered to be involved in attentional allocation. However, the characteristics of the encoded features and neuron responses in those attention related cortices are indefinite. Therefore, further investigations carried out in this study aim at demonstrating that unusual regions arousing more attention generally cause particular neuron responses. We suppose that visual saliency is obtained on the basis of neuron responses to contexts in natural scenes. A bottom-up visual attention model is proposed based on the self-information of neuron responses to test and verify the hypothesis. Four different color spaces are adopted and a novel entropy-based combination scheme is designed to make full use of color information. Valuable regions are highlighted while redundant backgrounds are suppressed in the saliency maps obtained by the proposed model. Comparative results reveal that the proposed model outperforms several state-of-the-art models. This study provides insights into the neuron responses based saliency detection and may underlie the neural mechanism of early visual cortices for bottom-up visual attention. PMID:25747859

Quantum Mechanics Approach to Hydration Energies and Structures of Alanine and Dialanine.

PubMed

Lanza, Giuseppe; Chiacchio, Maria A

2017-06-20

A systematic approach to the phenomena related to hydration of biomolecules is reported at the state of the art of electronic-structure methods. Large-scale CCSD(T), MP4-SDQ, MP2, and DFT(M06-2X) calculations for some hydrated complexes of alanine and dialanine (Ala⋅13 H 2 O, Ala 2 H + ⋅18 H 2 O, and Ala 2 ⋅18 H 2 O) are compared with experimental data and other elaborate modeling to assess the reliability of a simple bottom-up approach. The inclusion of a minimal number of water molecules for microhydration of the polar groups together with the polarizable continuum model is sufficient to reproduce the relative bulk thermodynamic functions of the considered biomolecules. These quantities depend on the adopted electronic-structure method, which should be chosen with great care. Nevertheless, the computationally feasible MP2 and M06-2X functionals with the aug-cc-pVTZ basis set satisfactorily reproduce values derived by high-level CCSD(T) and MP4-SDQ methods, and thus they are suitable for future developments of more elaborate and hence more biochemically significant peptides. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Complementarity As Generative Principle: A Thought Pattern for Aesthetic Appreciations and Cognitive Appraisals in General

PubMed Central

Bao, Yan; von Stosch, Alexandra; Park, Mona; Pöppel, Ernst

2017-01-01

In experimental aesthetics the relationship between the arts and cognitive neuroscience has gained particular interest in recent years. But has cognitive neuroscience indeed something to offer when studying the arts? Here we present a theoretical frame within which the concept of complementarity as a generative or creative principle is proposed; neurocognitive processes are characterized by the duality of complementary activities like bottom-up and top-down control, or logistical functions like temporal control and content functions like perceptions in the neural machinery. On that basis a thought pattern is suggested for aesthetic appreciations and cognitive appraisals in general. This thought pattern is deeply rooted in the history of philosophy and art theory since antiquity; and complementarity also characterizes neural operations as basis for cognitive processes. We then discuss some challenges one is confronted with in experimental aesthetics; in our opinion, one serious problem is the lack of a taxonomy of functions in psychology and neuroscience which is generally accepted. This deficit makes it next to impossible to develop acceptable models which are similar to what has to be modeled. Another problem is the severe language bias in this field of research as knowledge gained in many languages over the ages remains inaccessible to most scientists. Thus, an inspection of research results or theoretical concepts is necessarily too narrow. In spite of these limitations we provide a selective summary of some results and viewpoints with a focus on visual art and its appreciation. It is described how questions of art and aesthetic appreciations using behavioral methods and in particular brain-imaging techniques are analyzed and evaluated focusing on such issues like the representation of artwork or affective experiences. Finally, we emphasize complementarity as a generative principle on a practical level when artists and scientists work directly together which can lead to new insights and broader perspectives on both sides. PMID:28536548

Complementarity As Generative Principle: A Thought Pattern for Aesthetic Appreciations and Cognitive Appraisals in General.

PubMed

Bao, Yan; von Stosch, Alexandra; Park, Mona; Pöppel, Ernst

2017-01-01

In experimental aesthetics the relationship between the arts and cognitive neuroscience has gained particular interest in recent years. But has cognitive neuroscience indeed something to offer when studying the arts? Here we present a theoretical frame within which the concept of complementarity as a generative or creative principle is proposed; neurocognitive processes are characterized by the duality of complementary activities like bottom-up and top-down control, or logistical functions like temporal control and content functions like perceptions in the neural machinery. On that basis a thought pattern is suggested for aesthetic appreciations and cognitive appraisals in general. This thought pattern is deeply rooted in the history of philosophy and art theory since antiquity; and complementarity also characterizes neural operations as basis for cognitive processes. We then discuss some challenges one is confronted with in experimental aesthetics; in our opinion, one serious problem is the lack of a taxonomy of functions in psychology and neuroscience which is generally accepted. This deficit makes it next to impossible to develop acceptable models which are similar to what has to be modeled. Another problem is the severe language bias in this field of research as knowledge gained in many languages over the ages remains inaccessible to most scientists. Thus, an inspection of research results or theoretical concepts is necessarily too narrow. In spite of these limitations we provide a selective summary of some results and viewpoints with a focus on visual art and its appreciation. It is described how questions of art and aesthetic appreciations using behavioral methods and in particular brain-imaging techniques are analyzed and evaluated focusing on such issues like the representation of artwork or affective experiences. Finally, we emphasize complementarity as a generative principle on a practical level when artists and scientists work directly together which can lead to new insights and broader perspectives on both sides.

Nanoparticle Clusters: Assembly and Control Over Internal Order, Current Capabilities, and Future Potential.

PubMed

Stolarczyk, Jacek K; Deak, Andras; Brougham, Dermot F

2016-07-01

The current state of the art in the use of colloidal methods to form nanoparticle assemblies, or clusters (NPCs) is reviewed. The focus is on the two-step approach, which exploits the advantages of bottom-up wet chemical NP synthesis procedures, with subsequent colloidal destabilization to trigger assembly in a controlled manner. Recent successes in the application of functional NPCs with enhanced emergent collective properties for a wide range of applications, including in biomedical detection, surface enhanced Raman scattering (SERS) enhancement, photocatalysis, and light harvesting, are highlighted. The role of the NP-NP interactions in the formation of monodisperse ordered clusters is described and the different assembly processes from a wide range of literature sources are classified according to the nature of the perturbation from the initial equilibrium state (dispersed NPs). Finally, the future for the field and the anticipated role of computational approaches in developing next-generation functional NPCs are briefly discussed. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A top-down manner-based DCNN architecture for semantic image segmentation.

PubMed

Qiao, Kai; Chen, Jian; Wang, Linyuan; Zeng, Lei; Yan, Bin

2017-01-01

Given their powerful feature representation for recognition, deep convolutional neural networks (DCNNs) have been driving rapid advances in high-level computer vision tasks. However, their performance in semantic image segmentation is still not satisfactory. Based on the analysis of visual mechanism, we conclude that DCNNs in a bottom-up manner are not enough, because semantic image segmentation task requires not only recognition but also visual attention capability. In the study, superpixels containing visual attention information are introduced in a top-down manner, and an extensible architecture is proposed to improve the segmentation results of current DCNN-based methods. We employ the current state-of-the-art fully convolutional network (FCN) and FCN with conditional random field (DeepLab-CRF) as baselines to validate our architecture. Experimental results of the PASCAL VOC segmentation task qualitatively show that coarse edges and error segmentation results are well improved. We also quantitatively obtain about 2%-3% intersection over union (IOU) accuracy improvement on the PASCAL VOC 2011 and 2012 test sets.

Top down, bottom up structured programming and program structuring

NASA Technical Reports Server (NTRS)

Hamilton, M.; Zeldin, S.

1972-01-01

New design and programming techniques for shuttle software. Based on previous Apollo experience, recommendations are made to apply top-down structured programming techniques to shuttle software. New software verification techniques for large software systems are recommended. HAL, the higher order language selected for the shuttle flight code, is discussed and found to be adequate for implementing these techniques. Recommendations are made to apply the workable combination of top-down, bottom-up methods in the management of shuttle software. Program structuring is discussed relevant to both programming and management techniques.

Developing an Intelligent Automatic Appendix Extraction Method from Ultrasonography Based on Fuzzy ART and Image Processing.

PubMed

Kim, Kwang Baek; Park, Hyun Jun; Song, Doo Heon; Han, Sang-suk

2015-01-01

Ultrasound examination (US) does a key role in the diagnosis and management of the patients with clinically suspected appendicitis which is the most common abdominal surgical emergency. Among the various sonographic findings of appendicitis, outer diameter of the appendix is most important. Therefore, clear delineation of the appendix on US images is essential. In this paper, we propose a new intelligent method to extract appendix automatically from abdominal sonographic images as a basic building block of developing such an intelligent tool for medical practitioners. Knowing that the appendix is located at the lower organ area below the bottom fascia line, we conduct a series of image processing techniques to find the fascia line correctly. And then we apply fuzzy ART learning algorithm to the organ area in order to extract appendix accurately. The experiment verifies that the proposed method is highly accurate (successful in 38 out of 40 cases) in extracting appendix.

Patient attrition from the HIV antiretroviral therapy program at two hospitals in Haiti

PubMed Central

Puttkammer, Nancy H.; Zeliadt, Steven B.; Baseman, Janet G.; Destiné, Rodney; Domerçant, Jean Wysler; Coq, Nancy Rachel Labbé; Raphael, Nernst Atwood; Sherr, Kenneth; Tegger, Mary; Yuhas, Krista; Barnhart, Scott

2016-01-01

Objective To identify factors associated with antiretroviral therapy (ART) attrition among patients initiating therapy in 2005–2011 at two large, public-sector department-level hospitals, and to inform interventions to improve ART retention. Methods This retrospective cohort study used data from the iSanté electronic medical record (EMR) system. The study characterized ART attrition levels and explored the patient demographic, clinical, temporal, and service utilization factors associated with ART attrition, using time-to-event analysis methods. Results Among the 2 023 patients in the study, ART attrition on average was 17.0 per 100 person-years (95% confidence interval (CI): 15.8–18.3). In adjusted analyses, risk of ART attrition was up to 89% higher for patients living in distant communes compared to patients living in the same commune as the hospital (hazard ratio: 1.89, 95%CI: 1.54–2.33; P < 0.001). Hospital site, earlier year of ART start, spending less time enrolled in HIV care prior to ART initiation, receiving a non-standard ART regimen, lacking counseling prior to ART initiation, and having a higher body mass index were also associated with attrition risk. Conclusions The findings suggest quality improvement interventions at the two hospitals, including: enhanced retention support and transportation subsidies for patients accessing care from remote areas; counseling for all patients prior to ART initiation; timely outreach to patients who miss ART pick-ups; “bridging services” for patients transferring care to alternative facilities; routine screening for anticipated interruptions in future ART pick-ups; and medical case review for patients placed on non-standard ART regimens. The findings are also relevant for policymaking on decentralization of ART services in Haiti. PMID:25563149

Reconciling Basin-Scale Top-Down and Bottom-Up Methane Emission Measurements for Onshore Oil and Gas Development: Cooperative Research and Development Final Report, CRADA Number CRD-14-572

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

Heath, Garvin A.

The overall objective of the Research Partnership to Secure Energy for America (RPSEA)-funded research project is to develop independent estimates of methane emissions using top-down and bottom-up measurement approaches and then to compare the estimates, including consideration of uncertainty. Such approaches will be applied at two scales: basin and facility. At facility scale, multiple methods will be used to measure methane emissions of the whole facility (controlled dual tracer and single tracer releases, aircraft-based mass balance and Gaussian back-trajectory), which are considered top-down approaches. The bottom-up approach will sum emissions from identified point sources measured using appropriate source-level measurement techniquesmore » (e.g., high-flow meters). At basin scale, the top-down estimate will come from boundary layer airborne measurements upwind and downwind of the basin, using a regional mass balance model plus approaches to separate atmospheric methane emissions attributed to the oil and gas sector. The bottom-up estimate will result from statistical modeling (also known as scaling up) of measurements made at selected facilities, with gaps filled through measurements and other estimates based on other studies. The relative comparison of the bottom-up and top-down estimates made at both scales will help improve understanding of the accuracy of the tested measurement and modeling approaches. The subject of this CRADA is NREL's contribution to the overall project. This project resulted from winning a competitive solicitation no. RPSEA RFP2012UN001, proposal no. 12122-95, which is the basis for the overall project. This Joint Work Statement (JWS) details the contributions of NREL and Colorado School of Mines (CSM) in performance of the CRADA effort.« less

Creation of Functional Micro/Nano Systems through Top-down and Bottom-up Approaches

PubMed Central

Wong, Tak-Sing; Brough, Branden; Ho, Chih-Ming

2009-01-01

Mimicking nature’s approach in creating devices with similar functional complexity is one of the ultimate goals of scientists and engineers. The remarkable elegance of these naturally evolved structures originates from bottom-up self-assembly processes. The seamless integration of top-down fabrication and bottom-up synthesis is the challenge for achieving intricate artificial systems. In this paper, technologies necessary for guided bottom-up assembly such as molecular manipulation, molecular binding, and the self assembling of molecules will be reviewed. In addition, the current progress of synthesizing mechanical devices through top-down and bottom-up approaches will be discussed. PMID:19382535

Bottom-up coarse-grained models that accurately describe the structure, pressure, and compressibility of molecular liquids

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

Dunn, Nicholas J. H.; Noid, W. G., E-mail: wnoid@chem.psu.edu

2015-12-28

The present work investigates the capability of bottom-up coarse-graining (CG) methods for accurately modeling both structural and thermodynamic properties of all-atom (AA) models for molecular liquids. In particular, we consider 1, 2, and 3-site CG models for heptane, as well as 1 and 3-site CG models for toluene. For each model, we employ the multiscale coarse-graining method to determine interaction potentials that optimally approximate the configuration dependence of the many-body potential of mean force (PMF). We employ a previously developed “pressure-matching” variational principle to determine a volume-dependent contribution to the potential, U{sub V}(V), that approximates the volume-dependence of the PMF.more » We demonstrate that the resulting CG models describe AA density fluctuations with qualitative, but not quantitative, accuracy. Accordingly, we develop a self-consistent approach for further optimizing U{sub V}, such that the CG models accurately reproduce the equilibrium density, compressibility, and average pressure of the AA models, although the CG models still significantly underestimate the atomic pressure fluctuations. Additionally, by comparing this array of models that accurately describe the structure and thermodynamic pressure of heptane and toluene at a range of different resolutions, we investigate the impact of bottom-up coarse-graining upon thermodynamic properties. In particular, we demonstrate that U{sub V} accounts for the reduced cohesion in the CG models. Finally, we observe that bottom-up coarse-graining introduces subtle correlations between the resolution, the cohesive energy density, and the “simplicity” of the model.« less

Semi top-down method combined with earth-bank, an effective method for basement construction.

NASA Astrophysics Data System (ADS)

Tuan, B. Q.; Tam, Ng M.

2018-04-01

Choosing an appropriate method of deep excavation not only plays a decisive role in technical success, but also in economics of the construction project. Presently, we mainly base on to key methods: “Bottom-up” and “Top-down” construction method. Right now, this paper presents an another method of construction that is “Semi Top-down method combining with earth-bank” in order to take the advantages and limit the weakness of the above methods. The Bottom-up method was improved by using the earth-bank to stabilize retaining walls instead of the bracing steel struts. The Top-down method was improved by using the open cut method for the half of the earthwork quantities.

Using concept mapping to explore why patients become lost to follow up from an antiretroviral therapy program in the Zomba District of Malawi.

PubMed

Rachlis, Beth; Ahmad, Farah; van Lettow, Monique; Muula, Adamson S; Semba, Medson; Cole, Donald C

2013-06-11

Retention in antiretroviral therapy (ART) programmes remains a challenge in many settings including Malawi, in part due to high numbers of losses to follow-up. Concept Mapping (CM), a mix-method participatory approach, was used to explore why patients on ART are lost to follow-up (LTFU) by identifying: 1) factors that influence patient losses to follow-up and 2) barriers to effective and efficient tracing in Zomba, Malawi. CM sessions (brainstorming, sorting and rating, interpretation) were conducted in urban and rural settings in Zomba, Malawi. Participants included ART patients, ART providers, Health Surveillance Assistants, and health managers from the Zomba District Health Office. In brainstorming, participants generated statements in response to "A specific reason why an individual on ART becomes lost to follow-up is…" Participants then sorted and rated the consolidated list of brainstormed items. Analysis included inductive qualitative methods for grouping of data and quantitative cluster identification to produce visual maps which were then interpreted by participants. In total, 90 individuals brainstormed 371 statements, 64 consolidated statements were sorted (participant n = 46), and rated on importance and feasibility (participant n = 69). A nine-cluster concept map was generated and included both patient- and healthcare-related clusters such as: Stigma and Fears, Beliefs, Acceptance and Knowledge of ART, Access to ART, Poor Documentation, Social and Financial Support Issues, Health Worker Attitudes, Resources Needed for Effective Tracing, and Health Worker Issues Related to Tracing. Strategies to respond to the clusters were generated in Interpretation. Multiple patient- and healthcare focused factors influence why patients become LTFU. Findings have implications particularly for programs with limited resources struggling with the retention of ART patients.

Ribbon growing method and apparatus

NASA Technical Reports Server (NTRS)

Morrison, Andrew D. (Inventor)

1989-01-01

A method and apparatus are described which facilitate the growing of silicon ribbon. A container for molten silicon has a pair of passages in its bottom through which filaments extend to a level above the molten silicon, so as the filaments are pulled up they drag up molten silicon to form a ribbon. A pair of guides surround the filaments along most of the height of the molten silicon, so that the filament contacts only the upper portion of the melt. This permits a filament to be used which tends to contaminate the melt if it is in long term contact with the melt. This arrangement also enables a higher melt to be used without danger that the molten silicon will run out of any bottom hole.

The Search Conference as a Method in Planning Community Health Promotion Actions

PubMed Central

Magnus, Eva; Knudtsen, Margunn Skjei; Wist, Guri; Weiss, Daniel; Lillefjell, Monica

2016-01-01

Aims: The aim of this article is to describe and discuss how the search conference can be used as a method for planning health promotion actions in local communities. Design and methods: The article draws on experiences with using the method for an innovative project in health promotion in three Norwegian municipalities. The method is described both in general and how it was specifically adopted for the project. Results and conclusions: The search conference as a method was used to develop evidence-based health promotion action plans. With its use of both bottom-up and top-down approaches, this method is a relevant strategy for involving a community in the planning stages of health promotion actions in line with political expectations of participation, ownership, and evidence-based initiatives. Significance for public health This article describe and discuss how the Search conference can be used as a method when working with knowledge based health promotion actions in local communities. The article describe the sequences of the conference and shows how this have been adapted when planning and prioritizing health promotion actions in three Norwegian municipalities. The significance of the article is that it shows how central elements in the planning of health promotion actions, as participation and involvements as well as evidence was a fundamental thinking in how the conference were accomplished. The article continue discussing how the method function as both a top-down and a bottom-up strategy, and in what way working evidence based can be in conflict with a bottom-up strategy. The experiences described can be used as guidance planning knowledge based health promotion actions in communities. PMID:27747199

Comparison of Instream and Laboratory Methods of Measuring Sediment Oxygen Demand

USGS Publications Warehouse

Hall, Dennis C.; Berkas, Wayne R.

1988-01-01

Sediment oxygen demand (SOD) was determined at three sites in a gravel-bottomed central Missouri stream by: (1) two variations of an instream method, and (2) a laboratory method. SOD generally was greatest by the instream methods, which are considered more accurate, and least by the laboratory method. Disturbing stream sediment did not significantly decrease SOD by the instream method. Temperature ranges of up to 12 degree Celsius had no significant effect on the SOD. In the gravel-bottomed stream, the placement of chambers was critical to obtain reliable measurements. SOD rates were dependent on the method; therefore, care should be taken in comparing SOD data obtained by different methods. There is a need for a carefully researched standardized method for SOD determinations.

Where to start? Bottom-up attention improves working memory by determining encoding order.

PubMed

Ravizza, Susan M; Uitvlugt, Mitchell G; Hazeltine, Eliot

2016-12-01

The present study aimed to characterize the mechanism by which working memory is enhanced for items that capture attention because of their novelty or saliency-that is, via bottom-up attention. The first experiment replicated previous research by corroborating that bottom-up attention directed to an item is sufficient for enhancing working memory and, moreover, generalized the effect to the domain of verbal working memory. The subsequent 3 experiments sought to determine how bottom-up attention affects working memory. We considered 2 hypotheses: (1) Bottom-up attention enhances the encoded representation of the stimulus, similar to how voluntary attention functions, or (2) It affects the order of encoding by shifting priority onto the attended stimulus. By manipulating how stimuli were presented (simultaneous/sequential display) and whether the cue predicted the tested items, we found evidence that bottom-up attention improves working memory performance via the order of encoding hypothesis. This finding was observed across change detection and free recall paradigms. In contrast, voluntary attention improved working memory regardless of encoding order and showed greater effects on working memory. We conclude that when multiple information sources compete, bottom-up attention prioritizes the location at which encoding should begin. When encoding order is set, bottom-up attention has little or no benefit to working memory. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Interactions of Top-Down and Bottom-Up Mechanisms in Human Visual Cortex

PubMed Central

McMains, Stephanie; Kastner, Sabine

2011-01-01

Multiple stimuli present in the visual field at the same time compete for neural representation by mutually suppressing their evoked activity throughout visual cortex, providing a neural correlate for the limited processing capacity of the visual system. Competitive interactions among stimuli can be counteracted by top-down, goal-directed mechanisms such as attention, and by bottom-up, stimulus-driven mechanisms. Because these two processes cooperate in everyday life to bias processing toward behaviorally relevant or particularly salient stimuli, it has proven difficult to study interactions between top-down and bottom-up mechanisms. Here, we used an experimental paradigm in which we first isolated the effects of a bottom-up influence on neural competition by parametrically varying the degree of perceptual grouping in displays that were not attended. Second, we probed the effects of directed attention on the competitive interactions induced with the parametric design. We found that the amount of attentional modulation varied linearly with the degree of competition left unresolved by bottom-up processes, such that attentional modulation was greatest when neural competition was little influenced by bottom-up mechanisms and smallest when competition was strongly influenced by bottom-up mechanisms. These findings suggest that the strength of attentional modulation in the visual system is constrained by the degree to which competitive interactions have been resolved by bottom-up processes related to the segmentation of scenes into candidate objects. PMID:21228167

From lists of behaviour change techniques (BCTs) to structured hierarchies: comparison of two methods of developing a hierarchy of BCTs.

PubMed

Cane, James; Richardson, Michelle; Johnston, Marie; Ladha, Ruhina; Michie, Susan

2015-02-01

Behaviour change technique (BCT) Taxonomy v1 is a hierarchically grouped, consensus-based taxonomy of 93 BCTs for reporting intervention content. To enhance the use and understanding of BCTs, the aims of the present study were to (1) quantitatively examine the 'bottom-up' hierarchical structure of Taxonomy v1, (2) identify whether BCTs can be reliably mapped to theoretical domains using a 'top-down' theoretically driven approach, and (3) identify any overlap between the 'bottom-up' and 'top-down' groupings. The 'bottom-up' structure was examined for higher-order groupings using a dendrogram derived from hierarchical cluster analysis. For the theory-based 'top-down' structure, 18 experts sorted BCTs into 14 theoretical domains. Discriminant Content Validity was used to identify groupings, and chi-square tests and Pearson's residuals were used to examine the overlap between groupings. Behaviour change techniques relating to 'Reward and Punishment' and 'Cues and Cue Responses' were perceived as markedly different to other BCTs. Fifty-nine of the BCTs were reliably allocated to 12 of the 14 theoretical domains; 47 were significant and 12 were of borderline significance. Thirty-four of 208 'bottom-up' × 'top-down' pairings showed greater overlap than expected by chance. However, only six combinations achieved satisfactory evidence of similarity. The moderate overlap between the groupings indicates some tendency to implicitly conceptualize BCTs in terms of the same theoretical domains. Understanding the nature of the overlap will aid the conceptualization of BCTs in terms of theory and application. Further research into different methods of developing a hierarchical taxonomic structure of BCTs for international, interdisciplinary work is now required. Statement of contribution What is already known on this subject? Behaviour change interventions are effective in improving health care and health outcomes. The 'active' components of these interventions are behaviour change techniques and over 93 have been identified. Taxonomies of behaviour change techniques require structure to enable potential applications. What does this study add? This study identifies groups of BCTs to aid the recall of BCTs for intervention coding and design. It compares two methods of grouping--'bottom-up' and theory-based 'top-down'--and finds a moderate overlap. Building on identified BCT groups, it examines relationships between theoretical domains and BCTs. © 2014 The British Psychological Society.

Getting to the Bottom of L2 Listening Instruction: Making a Case for Bottom-Up Activities

ERIC Educational Resources Information Center

Siegel, Joseph; Siegel, Aki

2015-01-01

This paper argues for the incorporation of bottom-up activities for English as a foreign language (EFL) listening. It discusses theoretical concepts and pedagogic options for addressing bottom-up aural processing in the EFL classroom as well as how and why teachers may wish to include such activities in lessons. This discussion is augmented by a…

Care and Maintenance.

ERIC Educational Resources Information Center

Hampton, Carol D.; Hampton, Carolyn H.

1980-01-01

Described is a method for bringing the sea into the classroom by setting up a saltwater aquarium. Included is selection of an aquarium, filtering systems, water (whether natural salt or synthetic sea salts), bottom materials, setting up an aquarium, system stabilization, stocking an aquarium, and maintenance of the aquarium. (DS)

Early limited antiretroviral therapy is superior to deferred therapy in HIV-infected South African infants: results from the CHER (Children with HIV Early antiRetroviral) Randomized Trial

PubMed Central

Cotton, Mark F; Violari, Avy; Otwombe, Kennedy; Panchia, Ravindre; Dobbels, Els; Rabie, Helena; Josipovic, Deirdre; Liberty, Afaff; Lazarus, Erica; Innes, Steve; van Rensburg, Anita Janse; Pelser, Wilma; Truter, Handre; Madhi, Shabir A; Handelsman, Edward; Jean-Philippe, Patrick; McIntyre, James A; Gibb, Diana M; Babiker, Abdel G

2014-01-01

Background Interim results from the CHER trial showed that early antiretroviral therapy (ART) was life-saving for HIV-infected infants. Given limited options and potential for toxicity with life-long ART, CHER compared early limited ART with deferred ART. Methods CHER was an open 3-arm trial in HIV-infected asymptomatic infants aged <12 weeks with CD4% ≥25%. Infants were randomized to deferred (ART-Def) or immediate ART for 40weeks (ART-40W) or 96weeks (ART-96W), followed by interruption. Criteria for ART initiation in ART-Def and re-initiation after interruption were CD4% <25% in infancy; otherwise <20% or CDC severe stage B or stage C disease. Lopinavir-ritonavir, zidovudine, lamivudine was the first-line regimen at ART initiation and re-initiation. The primary endpoint was time-to-failure of first-line ART (immunological/clinical/virological) or death. Comparisons were by intent-to-treat, using time-to-event methods. Findings 377 infants were enrolled: median age 7.4weeks; CD4% 35% and HIV RNA log 5.7copies/ml. Median follow-up was 4.8 years; 34 (9%) were lost-to-follow-up. Median time to ART initiation in ART-Def was 20 (IQR 16–25) weeks. Time to restarting ART after interruption was 33 (26–45) weeks in ART-40W and 70 (35–109) weeks in ART-96W; at trial end 19% and 32% respectively, remained off ART. Proportions of follow-up time spent on ART were 81%, 70% and 69% in ART-Def, ART-40W and ART-96W arms. 48/125(38%), 32/126(25%) and 26/126(21%) children reached the primary endpoint; hazard ratio (95%CI), relative to ART-Def, was 0.59(0.38-0.93, p=0.02) for ART-40W and 0.47(0.27-0.76, p=0.002) for ART-96W. Seven children (3 ART-Def, 3 ART-40W, 1 ART-96W) switched to second-line ART. Interpretation Early limited ART had superior clinical/immunological outcome with no evidence of excess disease progression during subsequent interruption and less overall ART exposure than deferred ART. Longer time on primary ART permits longer subsequent interruption with marginally better outcomes. PMID:24209829

Top-Down and Bottom-Up Approaches in Engineering 1 T Phase Molybdenum Disulfide (MoS2 ): Towards Highly Catalytically Active Materials.

PubMed

Chua, Chun Kiang; Loo, Adeline Huiling; Pumera, Martin

2016-09-26

The metallic 1 T phase of MoS2 has been widely identified to be responsible for the improved performances of MoS2 in applications including hydrogen evolution reactions and electrochemical supercapacitors. To this aim, various synthetic methods have been reported to obtain 1 T phase-rich MoS2 . Here, the aim is to evaluate the efficiencies of the bottom-up (hydrothermal reaction) and top-down (chemical exfoliation) approaches in producing 1 T phase MoS2 . It is established in this study that the 1 T phase MoS2 produced through the bottom-up approach contains a high proportion of 1 T phase and demonstrates excellent electrochemical and electrical properties. Its performance in the hydrogen evolution reaction and electrochemical supercapacitors also surpassed that of 1 T phase MoS2 produced through a top-down approach. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Impact of Company-Level ART Provision to a Mining Workforce in South Africa: A Cost–Benefit Analysis

PubMed Central

Meyer-Rath, Gesine; Pienaar, Jan; Brink, Brian; van Zyl, Andrew; Muirhead, Debbie; Grant, Alison; Churchyard, Gavin; Watts, Charlotte; Vickerman, Peter

2015-01-01

Background HIV impacts heavily on the operating costs of companies in sub-Saharan Africa, with many companies now providing antiretroviral therapy (ART) programmes in the workplace. A full cost–benefit analysis of workplace ART provision has not been conducted using primary data. We developed a dynamic health-state transition model to estimate the economic impact of HIV and the cost–benefit of ART provision in a mining company in South Africa between 2003 and 2022. Methods and Findings A dynamic health-state transition model, called the Workplace Impact Model (WIM), was parameterised with workplace data on workforce size, composition, turnover, HIV incidence, and CD4 cell count development. Bottom-up cost analyses from the employer perspective supplied data on inpatient and outpatient resource utilisation and the costs of absenteeism and replacement of sick workers. The model was fitted to workforce HIV prevalence and separation data while incorporating parameter uncertainty; univariate sensitivity analyses were used to assess the robustness of the model findings. As ART coverage increases from 10% to 97% of eligible employees, increases in survival and retention of HIV-positive employees and associated reductions in absenteeism and benefit payments lead to cost savings compared to a scenario of no treatment provision, with the annual cost of HIV to the company decreasing by 5% (90% credibility interval [CrI] 2%–8%) and the mean cost per HIV-positive employee decreasing by 14% (90% CrI 7%–19%) by 2022. This translates into an average saving of US$950,215 (90% CrI US$220,879–US$1.6 million) per year; 80% of these cost savings are due to reductions in benefit payments and inpatient care costs. Although findings are sensitive to assumptions regarding incidence and absenteeism, ART is cost-saving under considerable parameter uncertainty and in all tested scenarios, including when prevalence is reduced to 1%—except when no benefits were paid out to employees leaving the workforce and when absenteeism rates were half of what data suggested. Scaling up ART further through a universal test and treat strategy doubles savings; incorporating ART for family members reduces savings but is still marginally cost-saving compared to no treatment. Our analysis was limited to the direct cost of HIV to companies and did not examine the impact of HIV prevention policies on the miners or their families, and a few model inputs were based on limited data, though in sensitivity analysis our results were found to be robust to changes to these inputs along plausible ranges. Conclusions Workplace ART provision can be cost-saving for companies in high HIV prevalence settings due to reductions in healthcare costs, absenteeism, and staff turnover. Company-sponsored HIV counselling and voluntary testing with ensuing treatment of all HIV-positive employees and family members should be implemented universally at workplaces in countries with high HIV prevalence. PMID:26327271

Shaping the Future of Nanomedicine: Anisotropy in Polymeric Nanoparticle Design

PubMed Central

Meyer, Randall A.; Green, Jordan J.

2015-01-01

Nanofabrication and biomedical applications of polymeric nanoparticles have become important areas of research. Biocompatible polymeric nanoparticles have been investigated for their use as delivery vehicles for therapeutic and diagnostic agents. Although polymeric nanoconstructs have traditionally been fabricated as isotropic spheres, anisotropic, non-spherical nanoparticles have gained interest in the biomaterials community due to their unique interactions with biological systems. Polymeric nanoparticles with different forms of anisotropy have been manufactured utilizing a variety of novel methods in recent years. In addition, they have enhanced physical, chemical, and biological properties compared to spherical nanoparticles, including increased targeting avidity and decreased non-specific in vivo clearance. With these desirable properties, anisotropic nanoparticles have been successfully utilized in many biomedical settings and have performed superiorly to analogous spherical nanoparticles. We summarize the current state-of-the-art fabrication methods for anisotropic polymeric nanoparticles including top-down, bottom-up, and microfluidic design approaches. We also summarize the current and potential future applications of these nanoparticles, including drug delivery, biological targeting, immunoengineering, and tissue engineering. Ongoing research into the properties and utility of anisotropic polymeric nanoparticles will prove critical to realizing their potential in nanomedicine. PMID:25981390

HCFC-142b emissions in China: An inventory for 2000 to 2050 basing on bottom-up and top-down methods

NASA Astrophysics Data System (ADS)

Han, Jiarui; Li, Li; Su, Shenshen; Hu, Jianxin; Wu, Jing; Wu, Yusheng; Fang, Xuekun

2014-05-01

1-Chloro-1,1-difluoroethane (HCFC-142b) is both ozone depleting substance included in the Montreal Protocol on Substances that Deplete the Ozone Layer (Montreal Protocol) and potent greenhouse gas with high global warming potential. As one of the major HCFC-142b consumption and production countries in the world, China's control action will contribute to both mitigating climate change and protecting ozone layer. Estimating China's HCFC-142b emission is a crucial step for understanding its emission status, drawing up phasing-out plan and evaluating mitigation effect. Both the bottom-up and top-down method were adopted in this research to estimate HCFC-142b emissions from China. Results basing on different methods were compared to test the effectiveness of two methods and validate inventory's reliability. Firstly, a national bottom-up emission inventory of HCFC-142b for China during 2000-2012 was established based on the 2006 IPCC Guidelines for National Greenhouse Gas Inventories and the Montreal Protocol, showing that in contrast to the downward trend revealed by existing results, HCFC-142b emissions kept increasing from 0.1 kt/yr in 2000 to the peak of 14.4 kt/yr in 2012. Meanwhile a top-down emission estimation was also developed using interspecies correlation method. By correlating atmospheric mixing ratio data of HCFC-142b and reference substance HCFC-22 sampled from four representative cities (Beijing, Hangzhou, Lanzhou and Guangzhou, for northern, eastern, western and southern China, respectively), China's HCFC-142b emission in 2012 was calculated. It was 16.24(13.90-18.58) kt, equivalent to 1.06 kt ODP and 37 Tg CO2-eq, taking up 9.78% (ODP) of total HCFCs emission in China or 30.5% of global HCFC-142b emission. This result was 12.7% higher than that in bottom-up inventory. Possible explanations were discussed. The consistency of two results lend credit to methods effectiveness and results reliability. Finally, future HCFC-142b emission was projected to 2050. Emission might experience a continuous increase from 14.9 kt/yr to 97.2 kt/yr under business-as-usual (BAU) scenario, while a 90% reduction would be obtained by fulfilling the Montreal Protocol, namely an accumulative mitigation of 1578 kt from 2013 to 2050, equal to 103 kt ODP, and 3504 Tg CO2 emissions. Therefore, China will contribute tremendously to the worldwide ozone protection and global warming mitigation by successfully phasing out HCFC-142b according to the Montreal Protocol schedule.

Factors associated with death and loss to follow-up in children on antiretroviral care in Mingalardon Specialist Hospital, Myanmar, 2006–2016

PubMed Central

Satyanarayana, Srinath; Isaakidis, Petros; Hone, San; Khaing, Aye Aye; Nguyen Binh, Hoa; Oo, Htun Nyunt

2018-01-01

Background Myanmar National AIDS programme’s priority is to improve the survival of all people living with HIV by providing anti-retroviral therapy (ART) care. More than 7200 children (aged <15 years) have been enrolled into ART care from 2005 to 2016. A previous study showed that ~11% children on ART care had either died or were lost to follow-up by 60 months. Factors associated with death and lost-to follow-up (adverse outcomes) have not been previously studied. Objectives To describe the association between demographic and clinical characteristics at enrollment into ART care with adverse outcomes. Methods Cohort study using records of children enrolled for ART care at Mingalardon Specialist Hospital (main Paediatric ART center in Myanmar) from 2006–2016. We used multivariable Cox proportional hazards regression models for analysis. Results 1,159 children were enrolled for ART care and they contributed a total of 1.45 million person-days of follow-up period. 112 (10%) had an adverse outcome during the follow-up time period (55 deaths, 57 lost to follow-up). Enrollment into the ART care through in-patient care department of the hospital, CD4 Cell count <50/mm3, enrollment during changing ART guidelines (different ART eligibility criteria and preferred ART regimen) were independently associated with higher hazards of adverse outcome. Receiving protease inhibitor-based ART regimen at enrollment was independently associated with lower hazards of adverse outcome. Age, sex, residing in urban or rural areas, WHO clinical stage, having TB at the time of enrollment, receiving cotrimoxazole prophylaxis were not statistically associated with adverse outcomes. Conclusion Our analysis reconfirms good survival of children on ART care (including those with TB). The characteristics associated with adverse outcomes (other than CD4 cell count<50) are surrogates of some unmeasured underlying health system/ patient related factors that needs further exploration to improve the survival of children on ART care. PMID:29621302

Retention and mortality on antiretroviral therapy in sub-Saharan Africa: collaborative analyses of HIV treatment programmes.

PubMed

Haas, Andreas D; Zaniewski, Elizabeth; Anderegg, Nanina; Ford, Nathan; Fox, Matthew P; Vinikoor, Michael; Dabis, François; Nash, Denis; Sinayobye, Jean d'Amour; Niyongabo, Thêodore; Tanon, Aristophane; Poda, Armel; Adedimeji, Adebola A; Edmonds, Andrew; Davies, Mary-Ann; Egger, Matthias

2018-02-01

By 2020, 90% of all people diagnosed with HIV should receive long-term combination antiretroviral therapy (ART). In sub-Saharan Africa, this target is threatened by loss to follow-up in ART programmes. The proportion of people retained on ART long-term cannot be easily determined, because individuals classified as lost to follow-up, may have self-transferred to another HIV treatment programme, or may have died. We describe retention on ART in sub-Saharan Africa, first based on observed data as recorded in the clinic databases, and second adjusted for undocumented deaths and self-transfers. We analysed data from HIV-infected adults and children initiating ART between 2009 and 2014 at a sub-Saharan African HIV treatment programme participating in the International epidemiology Databases to Evaluate AIDS (IeDEA). We used the Kaplan-Meier method to calculate the cumulative incidence of retention on ART and the Aalen-Johansen method to calculate the cumulative incidences of death, loss to follow-up, and stopping ART. We used inverse probability weighting to adjust clinic data for undocumented mortality and self-transfer, based on estimates from a recent systematic review and meta-analysis. We included 505,634 patients: 12,848 (2.5%) from Central Africa, 109,233 (21.6%) from East Africa, 347,343 (68.7%) from Southern Africa and 36,210 (7.2%) from West Africa. In crude analyses of observed clinic data, 52.1% of patients were retained on ART, 41.8% were lost to follow-up and 6.0% had died 5 years after ART initiation. After accounting for undocumented deaths and self-transfers, we estimated that 66.6% of patients were retained on ART, 18.8% had stopped ART and 14.7% had died at 5 years. Improving long-term retention on ART will be crucial to attaining the 90% on ART target. Naïve analyses of HIV cohort studies, which do not account for undocumented mortality and self-transfer of patients, may severely underestimate both mortality and retention on ART. © 2018 The Authors. Journal of the International AIDS Society published by John Wiley & sons Ltd on behalf of the International AIDS Society.

Two-stage sparse coding of region covariance via Log-Euclidean kernels to detect saliency.

PubMed

Zhang, Ying-Ying; Yang, Cai; Zhang, Ping

2017-05-01

In this paper, we present a novel bottom-up saliency detection algorithm from the perspective of covariance matrices on a Riemannian manifold. Each superpixel is described by a region covariance matrix on Riemannian Manifolds. We carry out a two-stage sparse coding scheme via Log-Euclidean kernels to extract salient objects efficiently. In the first stage, given background dictionary on image borders, sparse coding of each region covariance via Log-Euclidean kernels is performed. The reconstruction error on the background dictionary is regarded as the initial saliency of each superpixel. In the second stage, an improvement of the initial result is achieved by calculating reconstruction errors of the superpixels on foreground dictionary, which is extracted from the first stage saliency map. The sparse coding in the second stage is similar to the first stage, but is able to effectively highlight the salient objects uniformly from the background. Finally, three post-processing methods-highlight-inhibition function, context-based saliency weighting, and the graph cut-are adopted to further refine the saliency map. Experiments on four public benchmark datasets show that the proposed algorithm outperforms the state-of-the-art methods in terms of precision, recall and mean absolute error, and demonstrate the robustness and efficiency of the proposed method. Copyright © 2017 Elsevier Ltd. All rights reserved.

Self-organization of maze-like structures via guided wrinkling.

PubMed

Bae, Hyung Jong; Bae, Sangwook; Yoon, Jinsik; Park, Cheolheon; Kim, Kibeom; Kwon, Sunghoon; Park, Wook

2017-06-01

Sophisticated three-dimensional (3D) structures found in nature are self-organized by bottom-up natural processes. To artificially construct these complex systems, various bottom-up fabrication methods, designed to transform 2D structures into 3D structures, have been developed as alternatives to conventional top-down lithography processes. We present a different self-organization approach, where we construct microstructures with periodic and ordered, but with random architecture, like mazes. For this purpose, we transformed planar surfaces using wrinkling to directly use randomly generated ridges as maze walls. Highly regular maze structures, consisting of several tessellations with customized designs, were fabricated by precisely controlling wrinkling with the ridge-guiding structure, analogous to the creases in origami. The method presented here could have widespread applications in various material systems with multiple length scales.

Bottom-up fabrication of paper-based microchips by blade coating of cellulose microfibers on a patterned surface.

PubMed

Gao, Bingbing; Liu, Hong; Gu, Zhongze

2014-12-23

We report a method for the bottom-up fabrication of paper-based capillary microchips by the blade coating of cellulose microfibers on a patterned surface. The fabrication process is similar to the paper-making process in which an aqueous suspension of cellulose microfibers is used as the starting material and is blade-coated onto a polypropylene substrate patterned using an inkjet printer. After water evaporation, the cellulose microfibers form a porous, hydrophilic, paperlike pattern that wicks aqueous solution by capillary action. This method enables simple, fast, inexpensive fabrication of paper-based capillary channels with both width and height down to about 10 μm. When this method is used, the capillary microfluidic chip for the colorimetric detection of glucose and total protein is fabricated, and the assay requires only 0.30 μL of sample, which is 240 times smaller than for paper devices fabricated using photolithography.

Bottom-up or top-down: unit cost estimation of tuberculosis diagnostic tests in India.

PubMed

Rupert, S; Vassall, A; Raizada, N; Khaparde, S D; Boehme, C; Salhotra, V S; Sachdeva, K S; Nair, S A; Hoog, A H Van't

2017-04-01

Of 18 sites that participated in an implementation study of the Xpert® MTB/RIF assay in India, we selected five microscopy centres and two reference laboratories. To obtain unit costs of diagnostic tests for tuberculosis (TB) and drug-resistant TB. Laboratories were purposely selected to capture regional variations and different laboratory types. Both bottom-up and the top-down methods were used to estimate unit costs. At the microscopy centres, mean bottom-up unit costs were respectively US$0.83 (range US$0.60-US$1.10) and US$12.29 (US$11.61-US$12.89) for sputum smear microscopy and Xpert. At the reference laboratories, mean unit costs were US$1.69 for the decontamination procedure, US$9.83 for a solid culture, US$11.06 for a liquid culture, US$29.88 for a drug susceptibility test, and US$18.18 for a line-probe assay. Top-down mean unit cost estimates were higher for all tests, and for sputum smear microscopy and Xpert these increased to respectively US$1.51 and US$13.58. The difference between bottom-up and top-down estimates was greatest for tests performed at the reference laboratories. These unit costs for TB diagnostics can be used to estimate resource requirements and cost-effectiveness in India, taking into account geographical location, laboratory type and capacity utilisation.

Bottom-up Attention Orienting in Young Children with Autism

ERIC Educational Resources Information Center

Amso, Dima; Haas, Sara; Tenenbaum, Elena; Markant, Julie; Sheinkopf, Stephen J.

2014-01-01

We examined the impact of simultaneous bottom-up visual influences and meaningful social stimuli on attention orienting in young children with autism spectrum disorders (ASDs). Relative to typically-developing age and sex matched participants, children with ASDs were more influenced by bottom-up visual scene information regardless of whether…

Bottom-up vs. top-down effects on terrestrial insect herbivores: a meta-analysis.

PubMed

Vidal, Mayra C; Murphy, Shannon M

2018-01-01

Primary consumers are under strong selection from resource ('bottom-up') and consumer ('top-down') controls, but the relative importance of these selective forces is unknown. We performed a meta-analysis to compare the strength of top-down and bottom-up forces on consumer fitness, considering multiple predictors that can modulate these effects: diet breadth, feeding guild, habitat/environment, type of bottom-up effects, type of top-down effects and how consumer fitness effects are measured. We focused our analyses on the most diverse group of primary consumers, herbivorous insects, and found that in general top-down forces were stronger than bottom-up forces. Notably, chewing, sucking and gall-making herbivores were more affected by top-down than bottom-up forces, top-down forces were stronger than bottom-up in both natural and controlled (cultivated) environments, and parasitoids and predators had equally strong top-down effects on insect herbivores. Future studies should broaden the scope of focal consumers, particularly in understudied terrestrial systems, guilds, taxonomic groups and top-down controls (e.g. pathogens), and test for more complex indirect community interactions. Our results demonstrate the surprising strength of forces exerted by natural enemies on herbivorous insects, and thus the necessity of using a tri-trophic approach when studying insect-plant interactions. © 2017 John Wiley & Sons Ltd/CNRS.

Improving semantic scene understanding using prior information

NASA Astrophysics Data System (ADS)

Laddha, Ankit; Hebert, Martial

2016-05-01

Perception for ground robot mobility requires automatic generation of descriptions of the robot's surroundings from sensor input (cameras, LADARs, etc.). Effective techniques for scene understanding have been developed, but they are generally purely bottom-up in that they rely entirely on classifying features from the input data based on learned models. In fact, perception systems for ground robots have a lot of information at their disposal from knowledge about the domain and the task. For example, a robot in urban environments might have access to approximate maps that can guide the scene interpretation process. In this paper, we explore practical ways to combine such prior information with state of the art scene understanding approaches.

A bottom-up route to enhance thermoelectric figures of merit in graphene nanoribbons

PubMed Central

Sevinçli, Hâldun; Sevik, Cem; Çaın, Tahir; Cuniberti, Gianaurelio

2013-01-01

We propose a hybrid nano-structuring scheme for tailoring thermal and thermoelectric transport properties of graphene nanoribbons. Geometrical structuring and isotope cluster engineering are the elements that constitute the proposed scheme. Using first-principles based force constants and Hamiltonians, we show that the thermal conductance of graphene nanoribbons can be reduced by 98.8% at room temperature and the thermoelectric figure of merit, ZT, can be as high as 3.25 at T = 800 K. The proposed scheme relies on a recently developed bottom-up fabrication method, which is proven to be feasible for synthesizing graphene nanoribbons with an atomic precision. PMID:23390578

In vitro biodegradation testing of Mg-alloy EZK400 and manufacturing of implant prototypes using PM (powder metallurgy) methods.

PubMed

Wolff, M; Luczak, M; Schaper, J G; Wiese, B; Dahms, M; Ebel, T; Willumeit-Römer, R; Klassen, T

2018-09-01

The study is focussing towards Metal Injection Moulding (MIM) of Mg-alloys for biomedical implant applications. Especially the influence of the sintering processing necessary for the consolidation of the finished part is in focus of this study. In doing so, the chosen high strength EZK400 Mg-alloy powder material was sintered using different sintering support bottom plate materials to evaluate the possibility of iron impurity pick up during sintering. It can be shown that iron pick up took place from the steel bottom plate into the specimen. Despite the fact that a separating boron nitrite (BN) barrier layer was used and the Mg-Fe phase diagram is not predicting any significant solubility to each other. As a result of this study a new bottom plate material not harming the sintering and the biodegradation performance of the as sintered material, namely a carbon plate material, was found.

Alternate Perspectives on Concept Internalization: Learning Top Down Vs. Learning Bottom Up.

ERIC Educational Resources Information Center

Pines, A. Leon

This paper outlines two alternate ways in which concepts are acquired, known as "top down" and "bottom up". "Bottom up" refers to learning the members of a category and then extracting their similarities or differences, the rule or criterial attributes used to make the categorization. In the "top down"…

Bottom-up and top-down influences at untrained conditions determine perceptual learning specificity and transfer

PubMed Central

Xiong, Ying-Zi; Zhang, Jun-Yun; Yu, Cong

2016-01-01

Perceptual learning is often orientation and location specific, which may indicate neuronal plasticity in early visual areas. However, learning specificity diminishes with additional exposure of the transfer orientation or location via irrelevant tasks, suggesting that the specificity is related to untrained conditions, likely because neurons representing untrained conditions are neither bottom-up stimulated nor top-down attended during training. To demonstrate these top-down and bottom-up contributions, we applied a “continuous flash suppression” technique to suppress the exposure stimulus into sub-consciousness, and with additional manipulations to achieve pure bottom-up stimulation or top-down attention with the transfer condition. We found that either bottom-up or top-down influences enabled significant transfer of orientation and Vernier discrimination learning. These results suggest that learning specificity may result from under-activations of untrained visual neurons due to insufficient bottom-up stimulation and/or top-down attention during training. High-level perceptual learning thus may not functionally connect to these neurons for learning transfer. DOI: http://dx.doi.org/10.7554/eLife.14614.001 PMID:27377357

Perception and the art of depiction of cylindrical objects.

PubMed

Deregowski, Jan B; McGeorge, Peter

2008-01-01

Many works of art, notably those in the Byzantine tradition, contain depictions of upright cylindrical objects such that the outline of their top surfaces is incompatible with that of their bottom surfaces. We endeavour to elucidate whether this is a consequence of a painterly usage or a perceptual effect and conclude, on the basis of empirical evidence, that the latter cause is more likely.

Impeding 99Tc(IV) mobility in novel waste forms

DOE PAGES

Lee, Mal-Soon; Um, Wooyong; Wang, Guohui; ...

2016-06-30

Technetium ( 99Tc) is a long-lived radioactive fission product whose mobility in the subsurface is largely governed by its oxidation state1. Immobilization of Tc in mineral substrates is crucial for radioactive waste management and environmental remediation. Tc(IV) incorporation in spinels2, 3 has been proposed as a novel method to increase Tc retention in glass waste forms. However, experiments with Tc-magnetite under high temperature and oxic conditions showed re-oxidation of Tc(IV) to volatile pertechnetate Tc(VII)O4-.4, 5 Here we address this problem with large-scale ab initio molecular dynamics simulations and propose that elevated temperatures, 1st row transition metal dopants can significantly enhancemore » Tc retention in the order Co > Zn > Ni. Experiments with doped spinels at T=700 ºC provided quantitative confirmation of increased Tc retention in the same order predicted by theory. This work highlights the power of modern state-of-the-art simulations to provide essential insights and generate bottom-up design criteria of complex oxide materials at elevated temperatures.« less

Superpixel Cut for Figure-Ground Image Segmentation

NASA Astrophysics Data System (ADS)

Yang, Michael Ying; Rosenhahn, Bodo

2016-06-01

Figure-ground image segmentation has been a challenging problem in computer vision. Apart from the difficulties in establishing an effective framework to divide the image pixels into meaningful groups, the notions of figure and ground often need to be properly defined by providing either user inputs or object models. In this paper, we propose a novel graph-based segmentation framework, called superpixel cut. The key idea is to formulate foreground segmentation as finding a subset of superpixels that partitions a graph over superpixels. The problem is formulated as Min-Cut. Therefore, we propose a novel cost function that simultaneously minimizes the inter-class similarity while maximizing the intra-class similarity. This cost function is optimized using parametric programming. After a small learning step, our approach is fully automatic and fully bottom-up, which requires no high-level knowledge such as shape priors and scene content. It recovers coherent components of images, providing a set of multiscale hypotheses for high-level reasoning. We evaluate our proposed framework by comparing it to other generic figure-ground segmentation approaches. Our method achieves improved performance on state-of-the-art benchmark databases.

Combining De Novo Peptide Sequencing Algorithms, A Synergistic Approach to Boost Both Identifications and Confidence in Bottom-up Proteomics.

PubMed

Blank-Landeshammer, Bernhard; Kollipara, Laxmikanth; Biß, Karsten; Pfenninger, Markus; Malchow, Sebastian; Shuvaev, Konstantin; Zahedi, René P; Sickmann, Albert

2017-09-01

Complex mass spectrometry based proteomics data sets are mostly analyzed by protein database searches. While this approach performs considerably well for sequenced organisms, direct inference of peptide sequences from tandem mass spectra, i.e., de novo peptide sequencing, oftentimes is the only way to obtain information when protein databases are absent. However, available algorithms suffer from drawbacks such as lack of validation and often high rates of false positive hits (FP). Here we present a simple method of combining results from commonly available de novo peptide sequencing algorithms, which in conjunction with minor tweaks in data acquisition ensues lower empirical FDR compared to the analysis using single algorithms. Results were validated using state-of-the art database search algorithms as well specifically synthesized reference peptides. Thus, we could increase the number of PSMs meeting a stringent FDR of 5% more than 3-fold compared to the single best de novo sequencing algorithm alone, accounting for an average of 11 120 PSMs (combined) instead of 3476 PSMs (alone) in triplicate 2 h LC-MS runs of tryptic HeLa digestion.

Growth Patterns of HIV Infected Indian Children in Response to ART: A Clinic Based Cohort Study.

PubMed

Parchure, Ritu S; Kulkarni, Vinay V; Darak, Trupti S; Mhaskar, Rahul; Miladinovic, Branko; Emmanuel, Patricia J

2015-06-01

To describe catch-up growth after antiretroviral therapy (ART) initiation among children living with human immunodeficiency virus (CLHIV), attending a private clinic in India. This is a retrospective analysis of data of CLHIV attending Prayas clinic, Pune, India. Height and weight z scores (HAZ, WAZ) were calculated using WHO growth charts. Catch-up growth post-ART was assessed using a mixed method model in cases where baseline and at least one subsequent follow-up HAZ/WAZ were available. STATA 12 was used for statistical analysis. During 1998 to 2011, 466 children were enrolled (201 girls and 265 boys; median age = 7 y). A total of 302 children were ever started on ART; of which 73 and 76 children were included for analysis for catch up growth in WAZ and HAZ respectively. Median WAZ and HAZ increased from -2.14 to -1.34 (p = 0.007) and -2.42 to -1.94 (p = 0.34), respectively, 3 y post ART. Multivariable analysis using mixed model (adjusted for gender, guardianship, baseline age, baseline WAZ/HAZ, baseline and time varying WHO clinical stage) showed gains in WAZ (coef = 0.2, 95 % CI: -0.06 to 0.46) and HAZ (coef = 0.49, 95 % CI: 0.21 to 0.77) with time on ART. Lower baseline WAZ/HAZ and older age were associated with impaired catch-up growth. Children staying in institutions and with baseline advanced clinical stage showed higher gain in WAZ. The prevalence of stunting and underweight was high at ART initiation. Sustained catch-up growth was seen with ART. The study highlights the benefit of early ART in achieving normal growth in CLHIV.

Effect of antiretroviral therapy on clinical and immunologic disease progression in HIV positive children: One-year follow-up study

PubMed Central

Patel, Ankur; Trivedi, Sangeeta S.; Chudasama, Rajesh K.; Patel, Priyanka K.

2012-01-01

Objective: To study the effect of antiretroviral therapy (ART) on clinical, immunologic, and nutritional progression of disease in human immunodeficiency virus (HIV)-infected children for 1 year. Materials and Methods: The study included 54 children aged 1.5–15 years who registered at the ART center, Surat, from August 2007 to August 2009. During the study period, the children were followed-up at 6 monthly intervals up to 1 year after starting ART. World Health Organization (WHO) clinical staging and CD4 cell count as per national guidelines, and nutritional status were used to measure clinical and immunologic progression of disease up to 1 year. Results: Out of 54 children, mother-to-child transmission was reported in 96.2% children; for 74% of the children, both parents were HIV positive. All the children were classified according to WHO clinical staging into 4 stages and as per CD4 cell count (%), followed up at 6 and 12 months and the benefits with ART reported. At 12 months follow-up, 15% of the study group children had died. Both mean CD4 count and a relative percentage showed significant increase (P < 0.01) in the study group 1 year after ART. Conclusion: The present study reports benefits of ART in terms of clinical and immunologic progression of disease, nutritional status of HIV-infected children after 1 year of ART. PMID:23230384

Guidelines for bottom-up approach of nanocarbon film formation from pentacene using heated tungsten on quartz substrate without metal catalyst

NASA Astrophysics Data System (ADS)

Heya, Akira; Matsuo, Naoto

2018-04-01

The guidelines for a bottom-up approach of nanographene formation from pentacene using heated tungsten were investigated using a novel method called hot mesh deposition (HMD). In this method, a heated W mesh was set between a pentacene source and a quartz substrate. Pentacene molecules were decomposed by the heated W mesh. The generated pentacene-based decomposed precursors were then deposited on the quartz substrate. The pentacene dimer (peripentacene) was obtained from pentacene by HMD using two heated catalysts. As expected from the calculation with the density functional theory in the literature, it was confirmed that the pentacene dimer can be formed by a reaction between pentacene and 6,13-dihydropentacene. This technique can be applied to the formation of novel nanographene on various substrates without metal catalysts.

Bridging the Gap between the Nanometer-Scale Bottom-Up and Micrometer-Scale Top-Down Approaches for Site-Defined InP/InAs Nanowires.

PubMed

Zhang, Guoqiang; Rainville, Christophe; Salmon, Adrian; Takiguchi, Masato; Tateno, Kouta; Gotoh, Hideki

2015-11-24

This work presents a method that bridges the gap between the nanometer-scale bottom-up and micrometer-scale top-down approaches for site-defined nanostructures, which has long been a significant challenge for applications that require low-cost and high-throughput manufacturing processes. We realized the bridging by controlling the seed indium nanoparticle position through a self-assembly process. Site-defined InP nanowires were then grown from the indium-nanoparticle array in the vapor-liquid-solid mode through a "seed and grow" process. The nanometer-scale indium particles do not always occupy the same locations within the micrometer-scale open window of an InP exposed substrate due to the scale difference. We developed a technique for aligning the nanometer-scale indium particles on the same side of the micrometer-scale window by structuring the surface of a misoriented InP (111)B substrate. Finally, we demonstrated that the developed method can be used to grow a uniform InP/InAs axial-heterostructure nanowire array. The ability to form a heterostructure nanowire array with this method makes it possible to tune the emission wavelength over a wide range by employing the quantum confinement effect and thus expand the application of this technology to optoelectronic devices. Successfully pairing a controllable bottom-up growth technique with a top-down substrate preparation technique greatly improves the potential for the mass-production and widespread adoption of this technology.

Spatial bottom-up controls on fire likelihood vary across western North America

Treesearch

Sean A. Parks; Marc-Andre Parisien; Carol Miller

2012-01-01

The unique nature of landscapes has challenged our ability to make generalizations about the effects of bottom-up controls on fire regimes. For four geographically distinct fire-prone landscapes in western North America, we used a consistent simulation approach to quantify the influence of three key bottom-up factors, ignitions, fuels, and topography, on spatial...

Top-Down Beta Enhances Bottom-Up Gamma

PubMed Central

Thompson, William H.

2017-01-01

Several recent studies have demonstrated that the bottom-up signaling of a visual stimulus is subserved by interareal gamma-band synchronization, whereas top-down influences are mediated by alpha-beta band synchronization. These processes may implement top-down control of stimulus processing if top-down and bottom-up mediating rhythms are coupled via cross-frequency interaction. To test this possibility, we investigated Granger-causal influences among awake macaque primary visual area V1, higher visual area V4, and parietal control area 7a during attentional task performance. Top-down 7a-to-V1 beta-band influences enhanced visually driven V1-to-V4 gamma-band influences. This enhancement was spatially specific and largest when beta-band activity preceded gamma-band activity by ∼0.1 s, suggesting a causal effect of top-down processes on bottom-up processes. We propose that this cross-frequency interaction mechanistically subserves the attentional control of stimulus selection. SIGNIFICANCE STATEMENT Contemporary research indicates that the alpha-beta frequency band underlies top-down control, whereas the gamma-band mediates bottom-up stimulus processing. This arrangement inspires an attractive hypothesis, which posits that top-down beta-band influences directly modulate bottom-up gamma band influences via cross-frequency interaction. We evaluate this hypothesis determining that beta-band top-down influences from parietal area 7a to visual area V1 are correlated with bottom-up gamma frequency influences from V1 to area V4, in a spatially specific manner, and that this correlation is maximal when top-down activity precedes bottom-up activity. These results show that for top-down processes such as spatial attention, elevated top-down beta-band influences directly enhance feedforward stimulus-induced gamma-band processing, leading to enhancement of the selected stimulus. PMID:28592697

A variable resolution right TIN approach for gridded oceanographic data

NASA Astrophysics Data System (ADS)

Marks, David; Elmore, Paul; Blain, Cheryl Ann; Bourgeois, Brian; Petry, Frederick; Ferrini, Vicki

2017-12-01

Many oceanographic applications require multi resolution representation of gridded data such as for bathymetric data. Although triangular irregular networks (TINs) allow for variable resolution, they do not provide a gridded structure. Right TINs (RTINs) are compatible with a gridded structure. We explored the use of two approaches for RTINs termed top-down and bottom-up implementations. We illustrate why the latter is most appropriate for gridded data and describe for this technique how the data can be thinned. While both the top-down and bottom-up approaches accurately preserve the surface morphology of any given region, the top-down method of vertex placement can fail to match the actual vertex locations of the underlying grid in many instances, resulting in obscured topology/bathymetry. Finally we describe the use of the bottom-up approach and data thinning in two applications. The first is to provide thinned, variable resolution bathymetry data for tests of storm surge and inundation modeling, in particular hurricane Katrina. Secondly we consider the use of the approach for an application to an oceanographic data grid of 3-D ocean temperature.

Application of satellite observations for timely updates to global anthropogenic NOx emission inventories

NASA Astrophysics Data System (ADS)

Lamsal, L. N.; Martin, R. V.; Padmanabhan, A.; van Donkelaar, A.; Zhang, Q.; Sioris, C. E.; Chance, K.; Kurosu, T. P.; Newchurch, M. J.

2011-03-01

Anthropogenic emissions of nitrogen oxides (NOx) can change rapidly due to economic growth or control measures. Bottom-up emissions estimated using source-specific emission factors and activity statistics require years to compile and can become quickly outdated. We present a method to use satellite observations of tropospheric NO2 columns to estimate changes in NOx emissions. We use tropospheric NO2 columns retrieved from the SCIAMACHY satellite instrument for 2003-2009, the response of tropospheric NO2 columns to changes in NOx emissions determined from a global chemical transport model (GEOS-Chem), and the bottom-up anthropogenic NOx emissions for 2006 to hindcast and forecast the inventories. We evaluate our approach by comparing bottom-up and hindcast emissions for 2003. The two inventories agree within 6.0% globally and within 8.9% at the regional scale with consistent trends in western Europe, North America, and East Asia. We go on to forecast emissions for 2009. During 2006-2009, anthropogenic NOx emissions over land increase by 9.2% globally and by 18.8% from East Asia. North American emissions decrease by 5.7%.

Paradigm shift from self-assembly to commanded assembly of functional materials: recent examples in porphyrin/fullerene supramolecular systems

NASA Astrophysics Data System (ADS)

Li, Mao; Ishihara, Shinsuke; Ji, Qingmin; Akada, Misaho; Hill, Jonathan P.; Ariga, Katsuhiko

2012-10-01

Current nanotechnology based on top-down nanofabrication may encounter a variety of drawbacks in the near future so that development of alternative methods, including the so-called bottom-up approach, has attracted considerable attention. However, the bottom-up strategy, which often relies on spontaneous self-assembly, might be inefficient in the development of the requisite functional materials and systems. Therefore, assembly processes controlled by external stimuli might be a plausible strategy for the development of bottom-up nanotechnology. In this review, we demonstrate a paradigm shift from self-assembly to commanded assembly by describing several examples of assemblies of typical functional molecules, i.e. porphyrins and fullerenes. In the first section, we describe recent progress in the design and study of self-assembled and co-assembled supramolecular architectures of porphyrins and fullerenes. Then, we show examples of assembly induced by external stimuli. We emphasize the paradigm shift from self-assembly to commanded assembly by describing the recently developed electrochemical-coupling layer-by-layer (ECC-LbL) methodology.

Mass production of bulk artificial nacre with excellent mechanical properties.

PubMed

Gao, Huai-Ling; Chen, Si-Ming; Mao, Li-Bo; Song, Zhao-Qiang; Yao, Hong-Bin; Cölfen, Helmut; Luo, Xi-Sheng; Zhang, Fu; Pan, Zhao; Meng, Yu-Feng; Ni, Yong; Yu, Shu-Hong

2017-08-18

Various methods have been exploited to replicate nacre features into artificial structural materials with impressive structural and mechanical similarity. However, it is still very challenging to produce nacre-mimetics in three-dimensional bulk form, especially for further scale-up. Herein, we demonstrate that large-sized, three-dimensional bulk artificial nacre with comprehensive mimicry of the hierarchical structures and the toughening mechanisms of natural nacre can be facilely fabricated via a bottom-up assembly process based on laminating pre-fabricated two-dimensional nacre-mimetic films. By optimizing the hierarchical architecture from molecular level to macroscopic level, the mechanical performance of the artificial nacre is superior to that of natural nacre and many engineering materials. This bottom-up strategy has no size restriction or fundamental barrier for further scale-up, and can be easily extended to other material systems, opening an avenue for mass production of high-performance bulk nacre-mimetic structural materials in an efficient and cost-effective way for practical applications.Artificial materials that replicate the mechanical properties of nacre represent important structural materials, but are difficult to produce in bulk. Here, the authors exploit the bottom-up assembly of 2D nacre-mimetic films to fabricate 3D bulk artificial nacre with an optimized architecture and excellent mechanical properties.

Loss to Follow-Up in a Community Clinic in South Africa – Roles of Gender, Pregnancy and CD4 count

PubMed Central

Wang, Bingxia; Losina, Elena; Stark, Ruth; Munro, Alison; Walensky, Rochelle P.; Wilke, Marisa; Martin, Des; Lu, Zhigang; Freedberg, Kenneth A.; Wood, Robin

2013-01-01

Background Faith-based organizations have expanded access to antiretroviral therapy (ART) in community clinics across South Africa. Loss to follow-up (LTFU), however, limits both the potential individual and population treatment benefits and is an obstacle to optimal care. Objective To identify patient characteristics associated with LTFU six months after starting ART in patients in a large South African community clinic. Methods Patients initiating ART between April 2004 and October 2006 in one Catholic Relief Services HIV treatment clinic who had at least one follow-up visit were included in the analysis. Standardized instruments were used for data collection. Routine monitoring was performed every 6 months following ART initiation. Rates of LTFU over time were estimated by the Kaplan-Meier method. The log-rank test was used to examine the impact of age, baseline CD4 count, HIV RNA, gender and pregnancy status for women on LTFU. Cox proportional hazard regression was performed to analyze hazard ratios for LTFU. Results Data from 925 patients (age > 14 years), median age 36 years, 70% female (16% pregnant) were included in the analysis. Fifty one patients (6%) were lost to follow-up six months after ART initiation. When stratified by baseline CD4 count, gender and pregnancy status, pregnant women with lower baseline CD4 count (≤200 /μl) had 6.06 times (95% CI: 2.20 – 16.71) the hazard of LTFU compared to men. Conclusions HIV-infected pregnant women initiating ART are significantly more likely to be lost to follow-up in a community clinic in South Africa. Interventions to successfully retain pregnant women in care are urgently needed. PMID:21786730

THEMIS Art #118

NASA Image and Video Library

2013-07-17

Do you see what I see in this image from NASA Mars Odyssey spacecraft? These three side-by-side craters increase in size toward the bottom of the image. Looks like a snowman, only his eyes are missing.

Turning up the heat: temperature influences the relative importance of top-down and bottom-up effects.

PubMed

Hoekman, David

2010-10-01

Understanding how communities respond to changes in temperature is a major challenge for community ecology. Temperature influences the relative degree to which top-down and bottom-up forces structure ecological communities. In greenhouse experiments using the aquatic community found in pitcher plants (Sarracenia purpurea), I tested how temperature affected the relative importance of top-down (mosquito predation) and bottom-up (ant carcasses) forces on protozoa and bacteria populations. While bottom-up effects did not vary consistently with temperature, the top-down effects of predators on protozoa increased at higher temperatures. These results suggest that temperature could change the relative importance of top-down and bottom-up effects in ecological communities. Specifically, higher temperature may increase the strength of top-down effects by raising predator metabolic rate and concomitant processes (e.g., activity, foraging, digestion, growth) relative to cooler temperatures. These findings apply broadly to an understanding of trophic interactions in a variable environment and are especially relevant in the context of ongoing climate change.

Remote Sensing of Martian Terrain Hazards via Visually Salient Feature Detection

NASA Astrophysics Data System (ADS)

Al-Milli, S.; Shaukat, A.; Spiteri, C.; Gao, Y.

2014-04-01

The main objective of the FASTER remote sensing system is the detection of rocks on planetary surfaces by employing models that can efficiently characterise rocks in terms of semantic descriptions. The proposed technique abates some of the algorithmic limitations of existing methods with no training requirements, lower computational complexity and greater robustness towards visual tracking applications over long-distance planetary terrains. Visual saliency models inspired from biological systems help to identify important regions (such as rocks) in the visual scene. Surface rocks are therefore completely described in terms of their local or global conspicuity pop-out characteristics. These local and global pop-out cues are (but not limited to); colour, depth, orientation, curvature, size, luminance intensity, shape, topology etc. The currently applied methods follow a purely bottom-up strategy of visual attention for selection of conspicuous regions in the visual scene without any topdown control. Furthermore the choice of models used (tested and evaluated) are relatively fast among the state-of-the-art and have very low computational load. Quantitative evaluation of these state-ofthe- art models was carried out using benchmark datasets including the Surrey Space Centre Lab Testbed, Pangu generated images, RAL Space SEEKER and CNES Mars Yard datasets. The analysis indicates that models based on visually salient information in the frequency domain (SRA, SDSR, PQFT) are the best performing ones for detecting rocks in an extra-terrestrial setting. In particular the SRA model seems to be the most optimum of the lot especially that it requires the least computational time while keeping errors competitively low. The salient objects extracted using these models can then be merged with the Digital Elevation Models (DEMs) generated from the same navigation cameras in order to be fused to the navigation map thus giving a clear indication of the rock locations.

Direction with Discretion: Reading Recovery as an Example of Balancing Top-Down Policy and Bottom-Up Decision-Making.

ERIC Educational Resources Information Center

Scharer, Patricia L.; Zajano, Nancy C.

Educational policy analysts have recognized the need for an educational policy that combines the merits of "top-down" mandates with "bottom-up" teacher discretion. This paper describes the Reading Recovery program as an example of an educational program that balances top-down direction and bottom-up discretion by: (1) providing an overall…

A bottom-up method to develop pollution abatement cost curves for coal-fired utility boilers

EPA Science Inventory

This paper illustrates a new method to create supply curves for pollution abatement using boiler-level data that explicitly accounts for technology costs and performance. The Coal Utility Environmental Cost (CUECost) model is used to estimate retrofit costs for five different NO...

Disseminating effective clinician communication techniques: Engaging clinicians to want to learn how to engage patients.

PubMed

Pollak, Kathryn I; Back, Anthony L; Tulsky, James A

2017-10-01

Patient-clinician communication that promotes patient engagement enhances health care quality. Yet, disseminating effective communication interventions to practicing clinicians remains challenging. Current methods do not have large and sustainable effects. In this paper, we argue that both top-down approaches (mandated by institutions) should be coupled with bottom-up approaches that address clinician motivation, confidence, and barriers. We need to engage clinicians in the same way we ask them to engage patients - strategically and with empathy. We discuss potentially innovative strategies to integrate top-down and bottom-up approaches in ways that fit clinicians' busy schedules and can inform policy. Copyright © 2017. Published by Elsevier B.V.

Airborne Quantification of Methane Emissions in the San Francisco Bay Area of California

NASA Astrophysics Data System (ADS)

Guha, A.; Newman, S.; Martien, P. T.; Young, A.; Hilken, H.; Faloona, I. C.; Conley, S.

2017-12-01

The Bay Area Air Quality Management District, the San Francisco Bay Area's air quality regulatory agency, has set a goal to reduce the region's greenhouse gas (GHG) emissions 80% below 1990 levels by 2050, consistent with the State of California's climate protection goal. The Air District maintains a regional GHG emissions inventory that includes emissions estimates and projections which influence the agency's programs and regulatory activities. The Air District is currently working to better characterize methane emissions in the GHG inventory through source-specific measurements, to resolve differences between top-down regional estimates (Fairley and Fischer, 2015; Jeong et al., 2016) and the bottom-up inventory. The Air District funded and participated in a study in Fall 2016 to quantify methane emissions from a variety of sources from an instrumented Mooney aircraft. This study included 40 hours of cylindrical vertical profile flights that combined methane and wind measurements to derive mass emission rates. Simultaneous measurements of ethane provided source-apportionment between fossil-based and biological methane sources. The facilities sampled included all five refineries in the region, five landfills, two dairy farms and three wastewater treatment plants. The calculated mass emission rates were compared to bottom-up rates generated by the Air District and to those from facility reports to the US EPA as part of the mandatory GHG reporting program. Carbon dioxide emission rates from refineries are found to be similar to bottom-up estimates for all sources, supporting the efficacy of the airborne measurement methodology. However, methane emission estimates from the airborne method showed significant differences for some source categories. For example, methane emission estimates based on airborne measurements were up to an order of magnitude higher for refineries, and up to five times higher for landfills compared to bottom-up methods, suggesting significant underestimation in the inventories and self-reported estimates. Future measurements over the same facilities will reveal if we have seasonal and process-dependent trends in emissions. This will provide a basis for rule making and for designing mitigation and control actions.

Biased ART: a neural architecture that shifts attention toward previously disregarded features following an incorrect prediction.

PubMed

Carpenter, Gail A; Gaddam, Sai Chaitanya

2010-04-01

Memories in Adaptive Resonance Theory (ART) networks are based on matched patterns that focus attention on those portions of bottom-up inputs that match active top-down expectations. While this learning strategy has proved successful for both brain models and applications, computational examples show that attention to early critical features may later distort memory representations during online fast learning. For supervised learning, biased ARTMAP (bARTMAP) solves the problem of over-emphasis on early critical features by directing attention away from previously attended features after the system makes a predictive error. Small-scale, hand-computed analog and binary examples illustrate key model dynamics. Two-dimensional simulation examples demonstrate the evolution of bARTMAP memories as they are learned online. Benchmark simulations show that featural biasing also improves performance on large-scale examples. One example, which predicts movie genres and is based, in part, on the Netflix Prize database, was developed for this project. Both first principles and consistent performance improvements on all simulation studies suggest that featural biasing should be incorporated by default in all ARTMAP systems. Benchmark datasets and bARTMAP code are available from the CNS Technology Lab Website: http://techlab.bu.edu/bART/. Copyright 2009 Elsevier Ltd. All rights reserved.

Task Decomposition in Human Reliability Analysis

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

Boring, Ronald Laurids; Joe, Jeffrey Clark

2014-06-01

In the probabilistic safety assessments (PSAs) used in the nuclear industry, human failure events (HFEs) are determined as a subset of hardware failures, namely those hardware failures that could be triggered by human action or inaction. This approach is top-down, starting with hardware faults and deducing human contributions to those faults. Elsewhere, more traditionally human factors driven approaches would tend to look at opportunities for human errors first in a task analysis and then identify which of those errors is risk significant. The intersection of top-down and bottom-up approaches to defining HFEs has not been carefully studied. Ideally, both approachesmore » should arrive at the same set of HFEs. This question remains central as human reliability analysis (HRA) methods are generalized to new domains like oil and gas. The HFEs used in nuclear PSAs tend to be top-down— defined as a subset of the PSA—whereas the HFEs used in petroleum quantitative risk assessments (QRAs) are more likely to be bottom-up—derived from a task analysis conducted by human factors experts. The marriage of these approaches is necessary in order to ensure that HRA methods developed for top-down HFEs are also sufficient for bottom-up applications.« less

Analysis of top-down and bottom-up North American CO2 and CH4 emissions estimates in the second State of the Carbon Cycle Report

NASA Astrophysics Data System (ADS)

Miller, J. B.; Jacobson, A. R.; Bruhwiler, L.; Michalak, A.; Hayes, D. J.; Vargas, R.

2017-12-01

In just ten years since publication of the original State of the Carbon Cycle Report in 2007, global CO2 concentrations have risen by more than 22 ppm to 405 ppm. This represents 18% of the increase over preindustrial levels of 280 ppm. This increase is being driven unequivocally by fossil fuel combustion with North American emissions comprising roughly 20% of the global total over the past decade. At the global scale, we know by comparing well-known fossil fuel inventories and rates of atmospheric CO2 increase that about half of all emissions are absorbed at Earth's surface. For North America, however, we can not apply a simple mass balance to determine sources and sinks. Instead, contributions from ecosystems must be estimated using top-down and bottom-up methods. SOCCR-2 estimates North American net CO2 uptake from ecosystems using bottom-up (inventory) methods as 577 +/- 433 TgC/yr and 634 +/- 288 TgC/yr from top-down atmospheric inversions. Although the global terrestrial carbon sink is not precisely known, these values represent possibly 30% of the global values. As with net sink estimates reported in SOCCR, these new top-down and bottom-up estimates are statistically consistent with one another. However, the uncertainties on each of these estimates are now substantially smaller, giving us more confidence about where the truth lies. Atmospheric inversions also yield estimates of interannual variations (IAV) in CO2 and CH4 fluxes. Our syntheses suggest that IAV of ecosystem CO2 fluxes is of order 100 TgC/yr, mainly originating in the conterminous US, with lower variability in boreal and arctic regions. Moreover, this variability is much larger than for inventory-based fluxes reported by the US to the UNFCCC. Unlike CO2, bottom-up CH4 emissions are larger than those derived from large-scale atmospheric data, with the continental discrepancy resulting primarily from differences in arctic and boreal regions. In addition to the current state of the science, we will also discuss the primary sources of uncertainty and how existing and emerging measurement and modeling technologies can address them.

Bottom Topographic Changes of Poyang Lake During Past Decade Using Multi-temporal Satellite Images

NASA Astrophysics Data System (ADS)

Zhang, S.

2015-12-01

Poyang Lake, as a well-known international wetland in the Ramsar Convention List, is the largest freshwater lake in China. It plays crucial ecological role in flood storage and biological diversity. Poyang Lake is facing increasingly serious water crises, including seasonal dry-up, decreased wetland area, and water resource shortage, all of which are closely related to progressive bottom topographic changes over recent years. Time-series of bottom topography would contribute to our understanding of the lake's evolution during the past several decades. However, commonly used methods for mapping bottom topography fail to frequently update quality bathymetric data for Poyang Lake restricted by weather and accessibility. These deficiencies have limited our ability to characterize the bottom topographic changes and understanding lake erosion or deposition trend. To fill the gap, we construct a decadal bottom topography of Poyang Lake with a total of 146 time series medium resolution satellite images based on the Waterline Method. It was found that Poyang Lake has eroded with a rate of -14.4 cm/ yr from 2000 to 2010. The erosion trend was attributed to the impacts of human activities, especially the operation of the Three Gorge Dams, sand excavation, and the implementation of water conservancy project. A decadal quantitative understanding bottom topography of Poyang Lake might provide a foundation to model the lake evolutionary processes and assist both researchers and local policymakers in ecological management, wetland protection and lake navigation safety.

Mapping the Binding Interface of VEGF and a Monoclonal Antibody Fab-1 Fragment with Fast Photochemical Oxidation of Proteins (FPOP) and Mass Spectrometry

NASA Astrophysics Data System (ADS)

Zhang, Ying; Wecksler, Aaron T.; Molina, Patricia; Deperalta, Galahad; Gross, Michael L.

2017-05-01

We previously analyzed the Fab-1:VEGF (vascular endothelial growth factor) system described in this work, with both native top-down mass spectrometry and bottom-up mass spectrometry (carboxyl-group or GEE footprinting) techniques. This work continues bottom-up mass spectrometry analysis using a fast photochemical oxidation of proteins (FPOP) platform to map the solution binding interface of VEGF and a fragment antigen binding region of an antibody (Fab-1). In this study, we use FPOP to compare the changes in solvent accessibility by quantitating the extent of oxidative modification in the unbound versus bound states. Determining the changes in solvent accessibility enables the inference of the protein binding sites (epitope and paratopes) and a comparison to the previously published Fab-1:VEGF crystal structure, adding to the top-down and bottom-up data. Using this method, we investigated peptide-level and residue-level changes in solvent accessibility between the unbound proteins and bound complex. Mapping these data onto the Fab-1:VEGF crystal structure enabled successful characterization of both the binding region and regions of remote conformation changes. These data, coupled with our previous higher order structure (HOS) studies, demonstrate the value of a comprehensive toolbox of methods for identifying the putative epitopes and paratopes for biotherapeutic antibodies.

Bottom-Up or Top-Down: English as a Foreign Language Vocabulary Instruction for Chinese University Students

ERIC Educational Resources Information Center

Moskovsky, Christo; Jiang, Guowu; Libert, Alan; Fagan, Seamus

2015-01-01

Whereas there has been some research on the role of bottom-up and top-down processing in the learning of a second or foreign language, very little attention has been given to bottom-up and top-down instructional approaches to language teaching. The research reported here used a quasi-experimental design to assess the relative effectiveness of two…

First-principles chemical kinetic modeling of methyl trans-3-hexenoate epoxidation by HO 2

DOE PAGES

Cagnina, S.; Nicolle, Andre; de Bruin, T.; ...

2017-02-16

The design of innovative combustion processes relies on a comprehensive understanding of biodiesel oxidation kinetics. The present study aims at unraveling the reaction mechanism involved in the epoxidation of a realistic biodiesel surrogate, methyl trans-3-hexenoate, by hydroperoxy radicals using a bottom-up theoretical kinetics methodology. The obtained rate constants are in good agreement with experimental data for alkene epoxidation by HO 2. The impact of temperature and pressure on epoxidation pathways involving H-bonded and non-H-bonded conformers was assessed. As a result, the obtained rate constant was finally implemented into a state-of-the-art detailed combustion mechanism, resulting in fairly good agreement with enginemore » experiments.« less

Sub-10 nm patterning with DNA nanostructures: a short perspective

DOE PAGES

Du, Ke; Park, Myeongkee; Ding, Junjun; ...

2017-09-04

DNA is the hereditary material that contains our unique genetic code. Since the first demonstration of two-dimensional (2D) nanopatterns by using designed DNA origami ~10 years ago, DNA has evolved into a novel technique for 2D and 3D nanopatterning. It is now being used as a template for the creation of sub-10 nm structures via either 'top-down' or 'bottom-up' approaches for various applications spanning from nanoelectronics, plasmonic sensing, and nanophotonics. This paper starts with an histroric overview and discusses the current state-of-the-art in DNA nanolithography. Finally, emphasis is put on the challenges and prospects of DNA nanolithography as the nextmore » generation nanomanufacturing technique.« less

Nanoscaled surface patterning of conducting polymers.

PubMed

Jiang, Lin; Wang, Xing; Chi, Lifeng

2011-05-23

In continuing the steady development of integrated-circuit-related fabrication, the ability to pattern conducting polymers into smaller and smaller sizes in order to realize devices with enhanced performance or even wholly new properties begins to take a more prominent role in their advanced applications. This review summarizes the recent advances in top-down and bottom-up patterning of conducting polymers on surfaces with different approaches including direct writing, in-situ synthesis or assembly, etching, and nanoscratching. All of the latest emerging strategies have the potential to go beyond the current state of the art towards real progress in terms of high-precision positioning, high resolution, high throughout, higher stability, facile processing, and lower-cost production. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Sub-10 nm patterning with DNA nanostructures: a short perspective

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

Du, Ke; Park, Myeongkee; Ding, Junjun

DNA is the hereditary material that contains our unique genetic code. Since the first demonstration of two-dimensional (2D) nanopatterns by using designed DNA origami ~10 years ago, DNA has evolved into a novel technique for 2D and 3D nanopatterning. It is now being used as a template for the creation of sub-10 nm structures via either 'top-down' or 'bottom-up' approaches for various applications spanning from nanoelectronics, plasmonic sensing, and nanophotonics. This paper starts with an histroric overview and discusses the current state-of-the-art in DNA nanolithography. Finally, emphasis is put on the challenges and prospects of DNA nanolithography as the nextmore » generation nanomanufacturing technique.« less

Measurement of NOx fluxes from a tall tower in Beijing

NASA Astrophysics Data System (ADS)

Squires, Freya; Dunmore, Rachel; Lewis, Alastair; Vaughan, Adam; Mullinger, Neil; Nemitz, Eiko; Wild, Oliver; Zhang, Qiang; Hamilton, Jacqueline; Lee, James; Fu, Pingqing

2017-04-01

Nitrogen Oxides (NOx, the sum of nitrogen monoxide (NO) and nitrogen dioxide (NO2)) are significant anthropogenic pollutants emitted from most combustion processes. NOx is a precursor species to the formation of O3 and secondary aerosols and, in high concentrations, NO2 can have adverse effects on human health through action as a respiratory irritant. For these reasons, there has been increased focus on improving NOx emissions inventories, typically developed using 'bottom-up' estimates of emissions from their sources, which are used to predict current and future air quality and to guide abatement strategy. Recent studies have shown a discrepancy between NOx inventories and measured NOx emissions for UK cities, highlighting the limitations of bottom-up emissions inventories and the importance of accurate measurement data to improve the estimates. Similarly, inventories in China are associated with large uncertainties and are rapidly changing with time in response to economic development and new environmental regulation. Here, we present data collected as part of the Air Pollutants in Beijing (AIRPOLL-Beijing) campaign from an urban site located at the Institute of Atmospheric Physics, Chinese Academy of Sciences (IAP, CAS) (39˚ 58'28"N, 116˚ 22'16"E) in central Beijing. NOx concentrations were measured using a state-of-the-art chemiluminescence instrument, sampling from an inlet at 100 metres on a meteorological tower. Measurements at 5 Hz coupled with wind vector data measured by a sonic anemometer located at the same height as the inlet allowed NOx emission fluxes to be calculated using the eddy covariance method. Measurements were made during the period 11/11/2016 - 10/12/2016 and compared to existing emission estimates from The Multi-resolution Emission Inventory for China (MEIC) inventory. It is anticipated that this work will be used to evaluate the accuracy of emissions inventories for Beijing, to develop improved emissions estimates and thus provide greater information about the sources of NOx in the city.

Fabrication and characterization of ordered arrays of nanostructures

NASA Astrophysics Data System (ADS)

Larson, Preston

2005-11-01

Nanostructures are currently of great interest because of their unique properties and potential applications in a wide range of areas such as opto-electronic and biomedical devices. Current research in nanotechnology involves fabrication and characterization of these structures, as well as theoretical and experimental studies to explore their unique and novel properties. Not only do nanostructures have the potential to be both evolutionary (state-of-the-art ICs have more and more features on the nanoscale) but revolutionary (quantum computing) as well. In this thesis, a combination of bottom-up and top-down approaches is explored to fabricate ordered arrays of nanostrucutures. The bottom-up approach involves the growth of self-organized porous anodic aluminum oxide (AAO) films. AAO films consist of a well ordered hexagonal array of close-packed pores with diameters and spacings ranging from around 5 to 500 nm. Via a top-down approach, these AAO films are then used as masks or templates to fabricate ordered arrays of nanostructures (i.e. dots, holes, meshes, pillars, rings, etc.) of various materials using conventional deposition and/or etching techniques. Using AAO films as masks allows a simple and economical method to fabricate arrays of structures with nano-scale dimensions. Furthermore, they allow the fabrication of large areas (many millimeters on a side) of highly uniform and well-ordered arrays of nanostructures, a crucial requirement for most characterization techniques and applications. Characterization of these nanostructures using various techniques (electron microscopy, atomic force microscopy, UV-Vis absorption spectroscopy, photoluminescence, capacitance-voltage measurements, magnetization hysteresis curves, etc.) will be presented. Finally, these structures provide a unique opportunity to determine the single and collective properties of nanostructure arrays and will have various future applications including but not limited to: data storage, light emitting or sensing devices, nano-tribological coatings for surfaces, bio-sensors, filters, and more.

Viral Suppression and Retention in Care up to 5 Years after Initiation of Lifelong ART during Pregnancy (Option B+) in Rural Uganda

PubMed Central

Koss, Catherine A.; Natureeba, Paul; Kwarisiima, Dalsone; Ogena, Mike; Clark, Tamara D.; Olwoch, Peter; Cohan, Deborah; Okiring, Jaffer; Charlebois, Edwin D.; Kamya, Moses R.; Havlir, Diane V.

2016-01-01

Background Lifelong antiretroviral therapy (ART) is recommended for all HIV-infected pregnant women, but early studies suggest women often drop out of care postpartum and data are limited on virologic outcomes. Methods We evaluated viral suppression (primary outcome) and retention in care up to 5 years after ART initiation among HIV-infected women who started lifelong ART during pregnancy, irrespective of CD4 count, in a study in rural Uganda (NCT00993031). Participants were followed in the study for up to 1 year postpartum, then referred to clinics in surrounding communities. A random sample (N=200) was invited to participate in a cross-sectional follow-up study after completing the trial, involving one visit for a questionnaire and pregnancy and HIV RNA testing. Retention in care was defined as having attended an HIV clinic in the last 90 days. Logistic regression models were used to examine factors associated with viral suppression (HIV-1 RNA ≤400 copies/ml) at follow-up. Results One hundred fifty women (75%) were successfully contacted for follow-up at a median of 4.2 years after starting ART; 135 were retained in care (90%, 95% CI 84.0%–94.3%) and 121 demonstrated viral suppression (80.7%, 95% CI 73.4% –86.7%). Women who had disclosed their HIV status to their primary partner had greater odds of viral suppression (aOR 4.51, 95% CI 1.02–19.8). Conclusions High rates of viral suppression can be achieved up to 5 years after initiating ART during pregnancy among women retained in care. Interventions to facilitate disclosure may improve long-term outcomes among women who initiate ART during pregnancy under universal treatment. PMID:27828878

Drug nanosuspensions: a ZIP tool between traditional and innovative pharmaceutical formulations.

PubMed

Leone, Federica; Cavalli, Roberta

2015-01-01

A nanosuspension or nanocrystal suspension is a versatile formulation combining conventional and innovative features. It comprises 100% pure drug nanoparticles with sizes in the nano-scale range, generally stabilized by surfactants or polymers. Nanosuspensions are usually obtained in liquid media with bottom-up and top-down methods or by their combination. They have been designed to enhance the solubility, the dissolution rate and the bioavailability of drugs via various administration routes. Due to their small sizes, nanosuspensions can be also considered a drug delivery nanotechnology for the preparation of nanomedicine products. This review focuses on the state of the art of the nanocrystal-based formulation. It describes theory characteristics, design parameters, preparation methods, stability issues, as well as specific in vivo applications. Innovative strategies proposed to obtain nanomedicine formulation using nanocrystals are also reported. Many drug nanodelivery systems have been developed to increase the bioavailability of drugs and to decrease adverse side effects, but few can be industrially manufactured. Nanocrystals can close this gap by combining traditional and innovative drug formulations. Indeed, they can be used in many pharmaceutical dosage forms as such, or developed as new nano-scaled products. Engineered surface nanocrystals have recently been proposed as a dual strategy for stability enhancement and targeting delivery of nanocrystals.

Enzyme-catalyzed crosslinkable hydrogels: emerging strategies for tissue engineering.

PubMed

Teixeira, Liliana S Moreira; Feijen, Jan; van Blitterswijk, Clemens A; Dijkstra, Pieter J; Karperien, Marcel

2012-02-01

State-of-the-art bioactive hydrogels can easily and efficiently be formed by enzyme-catalyzed mild-crosslinking reactions in situ. Yet this cell-friendly and substrate-specific method remains under explored. Hydrogels prepared by using enzyme systems like tyrosinases, transferases and lysyl oxidases show interesting characteristics as dynamic scaffolds and as systems for controlled release. Increased attention is currently paid to hydrogels obtained via crosslinking of precursors by transferases or peroxidases as catalysts. Enzyme-mediated crosslinking has proven its efficiency and attention has now shifted to the development of enzymatically crosslinked hydrogels with higher degrees of complexity, mimicking extracellular matrices. Moreover, bottom-up approaches combining biocatalysts and self-assembly are being explored for the development of complex nano-scale architectures. In this review, the use of enzymatic crosslinking for the preparation of hydrogels as an innovative alternative to other crosslinking methods, such as the commonly used UV-mediated photo-crosslinking or physical crosslinking, will be discussed. Photo-initiator-based crosslinking may induce cytotoxicity in the formed gels, whereas physical crosslinking may lead to gels which do not have sufficient mechanical strength and stability. These limitations can be overcome using enzymes to form covalently crosslinked hydrogels. Herewith, we report the mechanisms involved and current applications, focusing on emerging strategies for tissue engineering and regenerative medicine. Copyright © 2011 Elsevier Ltd. All rights reserved.

Simplified methods of determining treatment retention in Malawi: ART cohort reports vs. pharmacy stock cards.

PubMed

Chan, A K; Singogo, E; Changamire, R; Ratsma, Y E C; Tassie, J-M; Harries, A D

2012-06-21

Rapid scale-up of antiretroviral therapy (ART) has challenged the health system in Malawi to monitor large numbers of patients effectively. To compare two methods of determining retention on treatment: quarterly ART clinic data aggregation vs. pharmacy stock cards. Between October 2010 and March 2011, data on ART outcomes were extracted from monitoring tools at five facilities. Pharmacy data on ART consumption were extracted. Workload for each method was observed and timed. We used intraclass correlation and Bland-Altman plots to compare the agreeability of both methods to determine treatment retention. There is wide variability between ART clinic cohort data and pharmacy data to determine treatment retention due to divergence in data at sites with large numbers of patients. However, there is a non-significant trend towards agreeability between the two methods (intraclass correlation coefficient > 0.9; P > 0.05). Pharmacy stock card monitoring is more time-efficient than quarterly ART data aggregation (81 min vs. 573 min). In low-resource settings, pharmacy records could be used to improve drug forecasting and estimate ART retention in a more time-efficient manner than quarterly data aggregation; however, a necessary precondition would be capacity building around pharmacy data management, particularly for large-sized cohorts.

Long-term immunologic and virologic responses on raltegravir-containing regimens among ART-experienced participants in the HIV Outpatient Study

PubMed Central

Buchacz, Kate; Wiegand, Ryan; Armon, Carl; Chmiel, Joan S.; Wood, Kathleen; Brooks, John T.; Palella, Frank J.

2015-01-01

Objectives Raltegravir (RAL)-containing antiretroviral therapy (ART) produced better immunologic and virologic responses than optimized background ART in clinical trials of heavily ART-experienced patients, but few data exist on long-term outcomes in routine HIV care. Methods We studied ART-experienced HIV outpatient study (HOPS) participants seen at 10 US HIV-specialty clinics during 2007–2011. We identified patients who started (baseline date) either continuous ≥30 days of RAL-containing or RAL-sparing ART, and used propensity score (PS) matching methods to account for baseline clinical and demographic differences. We used Kaplan–Meier methods and log-rank tests for the matched subsets to evaluate probability of death, achieving HIV RNA <50 copies/ml, and CD4 cell count (CD4) increase of ≥50 cells mm−3 during follow-up. Results Among 784 RAL-exposed and 1062 RAL-unexposed patients, 472 from each group were matched by PS. At baseline, the 472 RAL-exposed patients (mean nadir CD4, 205 cells mm−3; mean baseline CD4, 460 cells mm−3; HIV RNA <50 copies ml−1 in 61%; mean years on prescribed ART, 7.5) were similar to RAL unexposed. During a mean follow-up of over 3 years, mortality rates and immunologic and virologic trajectories did not differ between the two groups. Among patients with detectable baseline HIV RNA levels, 76% of RAL-exposed and 63% of RAL-unexposed achieved HIV RNA <50 copies ml−1 (P=0.51); 69 and 58%, respectively, achieved a CD4 increase ≥50 cells mm−3 (P=0.70). Discussion In our large cohort of US ART-experienced patients with a wide spectrum of clinical history, similar outcomes were observed when prescribed RAL containing versus other contemporary ART. PMID:26126549

Exploring responses to art in adolescence: a behavioral and eye-tracking study.

PubMed

Savazzi, Federica; Massaro, Davide; Di Dio, Cinzia; Gallese, Vittorio; Gilli, Gabriella; Marchetti, Antonella

2014-01-01

Adolescence is a peculiar age mainly characterized by physical and psychological changes that may affect the perception of one's own and others' body. This perceptual peculiarity may influence the way in which bottom-up and top-down processes interact and, consequently, the perception and evaluation of art. This study is aimed at investigating, by means of the eye-tracking technique, the visual explorative behavior of adolescents while looking at paintings. Sixteen color paintings, categorized as dynamic and static, were presented to twenty adolescents; half of the images represented natural environments and half human individuals; all stimuli were displayed under aesthetic and movement judgment tasks. Participants' ratings revealed that, generally, nature images are explicitly evaluated as more appealing than human images. Eye movement data, on the other hand, showed that the human body exerts a strong power in orienting and attracting visual attention and that, in adolescence, it plays a fundamental role during aesthetic experience. In particular, adolescents seem to approach human-content images by giving priority to elements calling forth movement and action, supporting the embodiment theory of aesthetic perception.

Exploring Responses to Art in Adolescence: A Behavioral and Eye-Tracking Study

PubMed Central

Savazzi, Federica; Massaro, Davide; Di Dio, Cinzia; Gallese, Vittorio; Gilli, Gabriella; Marchetti, Antonella

2014-01-01

Adolescence is a peculiar age mainly characterized by physical and psychological changes that may affect the perception of one's own and others' body. This perceptual peculiarity may influence the way in which bottom-up and top-down processes interact and, consequently, the perception and evaluation of art. This study is aimed at investigating, by means of the eye-tracking technique, the visual explorative behavior of adolescents while looking at paintings. Sixteen color paintings, categorized as dynamic and static, were presented to twenty adolescents; half of the images represented natural environments and half human individuals; all stimuli were displayed under aesthetic and movement judgment tasks. Participants' ratings revealed that, generally, nature images are explicitly evaluated as more appealing than human images. Eye movement data, on the other hand, showed that the human body exerts a strong power in orienting and attracting visual attention and that, in adolescence, it plays a fundamental role during aesthetic experience. In particular, adolescents seem to approach human-content images by giving priority to elements calling forth movement and action, supporting the embodiment theory of aesthetic perception. PMID:25048813

Bottom-up synthetic biology: modular design for making artificial platelets

NASA Astrophysics Data System (ADS)

Majumder, Sagardip; Liu, Allen P.

2018-01-01

Engineering artificial cells to mimic one or multiple fundamental cell biological functions is an emerging area of synthetic biology. Reconstituting functional modules from biological components in vitro is a challenging yet an important essence of bottom-up synthetic biology. Here we describe the concept of building artificial platelets using bottom-up synthetic biology and the four functional modules that together could enable such an ambitious effort.

Change Levers for Unifying Top-Down and Bottom-Up Approaches to the Adoption and Diffusion of e-Learning in Higher Education

ERIC Educational Resources Information Center

Singh, Gurmak; Hardaker, Glenn

2017-01-01

Using Giddens' theory of structuration as a theoretical framework, this paper outlines how five prominent United Kingdom universities aimed to integrate top-down and bottom-up approaches to the adoption and diffusion of e-learning. The aim of this paper is to examine the major challenges that arise from the convergence of bottom-up perspectives…

Reprint of "Two-stage sparse coding of region covariance via Log-Euclidean kernels to detect saliency".

PubMed

Zhang, Ying-Ying; Yang, Cai; Zhang, Ping

2017-08-01

In this paper, we present a novel bottom-up saliency detection algorithm from the perspective of covariance matrices on a Riemannian manifold. Each superpixel is described by a region covariance matrix on Riemannian Manifolds. We carry out a two-stage sparse coding scheme via Log-Euclidean kernels to extract salient objects efficiently. In the first stage, given background dictionary on image borders, sparse coding of each region covariance via Log-Euclidean kernels is performed. The reconstruction error on the background dictionary is regarded as the initial saliency of each superpixel. In the second stage, an improvement of the initial result is achieved by calculating reconstruction errors of the superpixels on foreground dictionary, which is extracted from the first stage saliency map. The sparse coding in the second stage is similar to the first stage, but is able to effectively highlight the salient objects uniformly from the background. Finally, three post-processing methods-highlight-inhibition function, context-based saliency weighting, and the graph cut-are adopted to further refine the saliency map. Experiments on four public benchmark datasets show that the proposed algorithm outperforms the state-of-the-art methods in terms of precision, recall and mean absolute error, and demonstrate the robustness and efficiency of the proposed method. Copyright © 2017 Elsevier Ltd. All rights reserved.

Patient attrition from the HIV antiretroviral therapy program at two hospitals in Haiti.

PubMed

Puttkammer, Nancy H; Zeliadt, Steven B; Baseman, Janet G; Destiné, Rodney; Wysler Domerçant, Jean; Labbé Coq, Nancy Rachel; Atwood Raphael, Nernst; Sherr, Kenneth; Tegger, Mary; Yuhas, Krista; Barnhart, Scott

2014-10-01

To identify factors associated with antiretroviral therapy (ART) attrition among patients initiating therapy in 2005-2011 at two large, public-sector department-level hospitals, and to inform interventions to improve ART retention. This retrospective cohort study used data from the iSanté electronic medical record (EMR) system. The study characterized ART attrition levels and explored the patient demographic, clinical, temporal, and service utilization factors associated with ART attrition, using time-to-event analysis methods. Among the 2 023 patients in the study, ART attrition on average was 17.0 per 100 person-years (95% confidence interval (CI): 15.8-18.3). In adjusted analyses, risk of ART attrition was up to 89% higher for patients living in distant communes compared to patients living in the same commune as the hospital (hazard ratio: 1.89, 95%CI: 1.54-2.33; P < 0.001). Hospital site, earlier year of ART start, spending less time enrolled in HIV care prior to ART initiation, receiving a non-standard ART regimen, lacking counseling prior to ART initiation, and having a higher body mass index were also associated with attrition risk. The findings suggest quality improvement interventions at the two hospitals, including: enhanced retention support and transportation subsidies for patients accessing care from remote areas; counseling for all patients prior to ART initiation; timely outreach to patients who miss ART pick-ups; "bridging services" for patients transferring care to alternative facilities; routine screening for anticipated interruptions in future ART pick-ups; and medical case review for patients placed on non-standard ART regimens. The findings are also relevant for policymaking on decentralization of ART services in Haiti.

Influence of model assumptions about HIV disease progression after initiating or stopping treatment on estimates of infections and deaths averted by scaling up antiretroviral therapy

PubMed Central

Sucharitakul, Kanes; Boily, Marie-Claude; Dimitrov, Dobromir

2018-01-01

Background Many mathematical models have investigated the population-level impact of expanding antiretroviral therapy (ART), using different assumptions about HIV disease progression on ART and among ART dropouts. We evaluated the influence of these assumptions on model projections of the number of infections and deaths prevented by expanded ART. Methods A new dynamic model of HIV transmission among men who have sex with men (MSM) was developed, which incorporated each of four alternative assumptions about disease progression used in previous models: (A) ART slows disease progression; (B) ART halts disease progression; (C) ART reverses disease progression by increasing CD4 count; (D) ART reverses disease progression, but disease progresses rapidly once treatment is stopped. The model was independently calibrated to HIV prevalence and ART coverage data from the United States under each progression assumption in turn. New HIV infections and HIV-related deaths averted over 10 years were compared for fixed ART coverage increases. Results Little absolute difference (<7 percentage points (pp)) in HIV infections averted over 10 years was seen between progression assumptions for the same increases in ART coverage (varied between 33% and 90%) if ART dropouts reinitiated ART at the same rate as ART-naïve MSM. Larger differences in the predicted fraction of HIV-related deaths averted were observed (up to 15pp). However, if ART dropouts could only reinitiate ART at CD4<200 cells/μl, assumption C predicted substantially larger fractions of HIV infections and deaths averted than other assumptions (up to 20pp and 37pp larger, respectively). Conclusion Different disease progression assumptions on and post-ART interruption did not affect the fraction of HIV infections averted with expanded ART, unless ART dropouts only re-initiated ART at low CD4 counts. Different disease progression assumptions had a larger influence on the fraction of HIV-related deaths averted with expanded ART. PMID:29554136

New, national bottom-up estimate for tree-based biological ...

EPA Pesticide Factsheets

Nitrogen is a limiting nutrient in many ecosystems, but is also a chief pollutant from human activity. Quantifying human impacts on the nitrogen cycle and investigating natural ecosystem nitrogen cycling both require an understanding of the magnitude of nitrogen inputs from biological nitrogen fixation (BNF). A bottom-up approach to estimating BNF—scaling rates up from measurements to broader scales—is attractive because it is rooted in actual BNF measurements. However, bottom-up approaches have been hindered by scaling difficulties, and a recent top-down approach suggested that the previous bottom-up estimate was much too large. Here, we used a bottom-up approach for tree-based BNF, overcoming scaling difficulties with the systematic, immense (>70,000 N-fixing trees) Forest Inventory and Analysis (FIA) database. We employed two approaches to estimate species-specific BNF rates: published ecosystem-scale rates (kg N ha-1 yr-1) and published estimates of the percent of N derived from the atmosphere (%Ndfa) combined with FIA-derived growth rates. Species-specific rates can vary for a variety of reasons, so for each approach we examined how different assumptions influenced our results. Specifically, we allowed BNF rates to vary with stand age, N-fixer density, and canopy position (since N-fixation is known to require substantial light).Our estimates from this bottom-up technique are several orders of magnitude lower than previous estimates indicating

Cruise report for P1-13-LA, U.S. Geological Survey gas hydrates research cruise, R/V Pelican April 18 to May 3, 2013, deepwater Gulf of Mexico

USGS Publications Warehouse

Haines, Seth S.; Hart, Patrick E.; Ruppel, Carolyn; O'Brien, Thomas; Baldwin, Wayne; White, Jenny; Moore, Eric; Dal Ferro, Peter; Lemmond, Peter

2014-01-01

The U.S. Geological Survey led a seismic acquisition cruise in the Gulf of Mexico from April 18 to May 3, 2013, with the objectives of (1) achieving improved imaging and characterization at two established gas hydrate study sites, and (2) refining geophysical methods for gas hydrate characterization in other locations. We conducted this acquisition aboard the R/V Pelican, and used a pair of 105/105-cubic-inch generator/injector air guns to provide seismic energy that we recorded using a 450-meter 72-channel digital hydrophone streamer and 25 multicomponent ocean-bottom seismometers. In the area of lease block Green Canyon 955, we deployed 21 ocean-bottom seismometers and acquired approximately 400 kilometers of high-resolution two-dimensional streamer seismic data in a grid with line spacing as small as 50 meters and along radial lines that provide source offsets up to 10 kilometers and diverse azimuths for the ocean-bottom seismometers. In the area of lease block Walker Ridge 313, we deployed 25 ocean-bottom seismometers and acquired approximately 450 kilometers of streamer seismic data in a grid pattern with line spacing as small as 250 meters and along radial lines that provide source offsets up to 10 kilometers for the ocean-bottom seismometers. The data acquisition effort was conducted safely and met the scientific objectives.

Climate-mediated changes in marine ecosystem regulation during El Niño.

PubMed

Lindegren, Martin; Checkley, David M; Koslow, Julian A; Goericke, Ralf; Ohman, Mark D

2018-02-01

The degree to which ecosystems are regulated through bottom-up, top-down, or direct physical processes represents a long-standing issue in ecology, with important consequences for resource management and conservation. In marine ecosystems, the role of bottom-up and top-down forcing has been shown to vary over spatio-temporal scales, often linked to highly variable and heterogeneously distributed environmental conditions. Ecosystem dynamics in the Northeast Pacific have been suggested to be predominately bottom-up regulated. However, it remains unknown to what extent top-down regulation occurs, or whether the relative importance of bottom-up and top-down forcing may shift in response to climate change. In this study, we investigate the effects and relative importance of bottom-up, top-down, and physical forcing during changing climate conditions on ecosystem regulation in the Southern California Current System (SCCS) using a generalized food web model. This statistical approach is based on nonlinear threshold models and a long-term data set (~60 years) covering multiple trophic levels from phytoplankton to predatory fish. We found bottom-up control to be the primary mode of ecosystem regulation. However, our results also demonstrate an alternative mode of regulation represented by interacting bottom-up and top-down forcing, analogous to wasp-waist dynamics, but occurring across multiple trophic levels and only during periods of reduced bottom-up forcing (i.e., weak upwelling, low nutrient concentrations, and primary production). The shifts in ecosystem regulation are caused by changes in ocean-atmosphere forcing and triggered by highly variable climate conditions associated with El Niño. Furthermore, we show that biota respond differently to major El Niño events during positive or negative phases of the Pacific Decadal Oscillation (PDO), as well as highlight potential concerns for marine and fisheries management by demonstrating increased sensitivity of pelagic fish to exploitation during El Niño. © 2017 John Wiley & Sons Ltd.

Electrooptic polymer voltage sensor and method of manufacture thereof

NASA Technical Reports Server (NTRS)

Gottsche, Allan (Inventor); Perry, Joseph W. (Inventor)

1993-01-01

An optical voltage sensor utilizing an electrooptic polymer is disclosed for application to electric power distribution systems. The sensor, which can be manufactured at low cost in accordance with a disclosed method, measures voltages across a greater range than prior art sensors. The electrooptic polymer, which replaces the optical crystal used in prior art sensors, is sandwiched directly between two high voltage electrodes. Voltage is measured by fiber optical means, and no voltage division is required. The sample of electrooptic polymer is fabricated in a special mold and later mounted in a sensor housing. Alternatively, mold and sensor housing may be identical. The sensor housing is made out of a machinable polymeric material and is equipped with two opposing optical windows. The optical windows are mounted in the bottom of machined holes in the wall of the mold. These holes provide for mounting of the polarizing optical components and for mounting of the fiber optic connectors. One connecting fiber is equipped with a light emitting diode as a light source. Another connecting fiber is equipped with a photodiode as a detector.

Word sense disambiguation in the clinical domain: a comparison of knowledge-rich and knowledge-poor unsupervised methods

PubMed Central

Chasin, Rachel; Rumshisky, Anna; Uzuner, Ozlem; Szolovits, Peter

2014-01-01

Objective To evaluate state-of-the-art unsupervised methods on the word sense disambiguation (WSD) task in the clinical domain. In particular, to compare graph-based approaches relying on a clinical knowledge base with bottom-up topic-modeling-based approaches. We investigate several enhancements to the topic-modeling techniques that use domain-specific knowledge sources. Materials and methods The graph-based methods use variations of PageRank and distance-based similarity metrics, operating over the Unified Medical Language System (UMLS). Topic-modeling methods use unlabeled data from the Multiparameter Intelligent Monitoring in Intensive Care (MIMIC II) database to derive models for each ambiguous word. We investigate the impact of using different linguistic features for topic models, including UMLS-based and syntactic features. We use a sense-tagged clinical dataset from the Mayo Clinic for evaluation. Results The topic-modeling methods achieve 66.9% accuracy on a subset of the Mayo Clinic's data, while the graph-based methods only reach the 40–50% range, with a most-frequent-sense baseline of 56.5%. Features derived from the UMLS semantic type and concept hierarchies do not produce a gain over bag-of-words features in the topic models, but identifying phrases from UMLS and using syntax does help. Discussion Although topic models outperform graph-based methods, semantic features derived from the UMLS prove too noisy to improve performance beyond bag-of-words. Conclusions Topic modeling for WSD provides superior results in the clinical domain; however, integration of knowledge remains to be effectively exploited. PMID:24441986

Exploring the underlying structure of mental disorders: cross-diagnostic differences and similarities from a network perspective using both a top-down and a bottom-up approach.

PubMed

Wigman, J T W; van Os, J; Borsboom, D; Wardenaar, K J; Epskamp, S; Klippel, A; Viechtbauer, W; Myin-Germeys, I; Wichers, M

2015-08-01

It has been suggested that the structure of psychopathology is best described as a complex network of components that interact in dynamic ways. The goal of the present paper was to examine the concept of psychopathology from a network perspective, combining complementary top-down and bottom-up approaches using momentary assessment techniques. A pooled Experience Sampling Method (ESM) dataset of three groups (individuals with a diagnosis of depression, psychotic disorder or no diagnosis) was used (pooled N = 599). The top-down approach explored the network structure of mental states across different diagnostic categories. For this purpose, networks of five momentary mental states ('cheerful', 'content', 'down', 'insecure' and 'suspicious') were compared between the three groups. The complementary bottom-up approach used principal component analysis to explore whether empirically derived network structures yield meaningful higher order clusters. Individuals with a clinical diagnosis had more strongly connected moment-to-moment network structures, especially the depressed group. This group also showed more interconnections specifically between positive and negative mental states than the psychotic group. In the bottom-up approach, all possible connections between mental states were clustered into seven main components that together captured the main characteristics of the network dynamics. Our combination of (i) comparing network structure of mental states across three diagnostically different groups and (ii) searching for trans-diagnostic network components across all pooled individuals showed that these two approaches yield different, complementary perspectives in the field of psychopathology. The network paradigm therefore may be useful to map transdiagnostic processes.

Comparative higher-order structure analysis of antibody biosimilars using combined bottom-up and top-down hydrogen-deuterium exchange mass spectrometry.

PubMed

Pan, Jingxi; Zhang, Suping; Borchers, Christoph H

2016-12-01

Hydrogen/deuterium exchange (HDX) coupled with mass spectrometry (MS) is a powerful technique for higher-order structural characterization of antibodies. Although the peptide-based bottom-up HDX approach and the protein-based top-down HDX approach have complementary advantages, the work done so far on biosimilars has involved only one or the other approach. Herein we have characterized the structures of two bevacizumab (BEV) biosimilars and compared them to the reference BEV using both methods. A sequence coverage of 87% was obtained for the heavy chain and 74% for the light chain in the bottom-up approach. The deuterium incorporation behavior of the peptic peptides from the three BEVs were compared side by side and showed no differences at various HDX time points. Top-down experiments were carried out using subzero temperature LC-MS, and the deuterium incorporation of the intact light chain and heavy chain were obtained. Top-down ETD was also performed to obtain amino acid-level HDX information that covered 100% of the light chain, but only 50% coverage is possible for the heavy chain. Consistent with the intact subunit level data, no differences were observed in the amino acid level HDX data. All these results indicate that there are no differences between the three BEV samples with respect to their high-order structures. The peptide level information from the bottom-up approach, and the residue level and intact subunit level information from the top-down approach were complementary and covered the entire antibody. Copyright © 2016 Elsevier B.V. All rights reserved.

A Daily Analysis of Physical Activity and Satisfaction with Life in Emerging Adults

PubMed Central

Maher, Jaclyn P.; Doerksen, Shawna E.; Elavsky, Steriani; Hyde, Amanda L.; Pincus, Aaron L.; Ram, Nilam; Conroy, David E.

2014-01-01

Objective Subjective well-being has well-established positive health consequences. During emerging adulthood, from ages 18 to 25 years, people’s global evaluations of their well-being (i.e., satisfaction with life [SWL]) appear to worsen more than any other time in the adult lifespan, indicating that this population would benefit from strategies to enhance SWL. In these studies, we investigated top-down (i.e., time-invariant, trait-like) and bottom-up (i.e., time-varying, state-like) influences of physical activity (PA) on daily SWL. Methods Two daily diary studies lasting 8 days (N = 190) and 14 days (N = 63) were conducted with samples of emerging adults enrolled in college to evaluate relations between daily PA and SWL while controlling for established and plausible top-down and bottom-up influences on SWL. Results In both studies, multilevel models indicated that people reported greater SWL on days when they were more active (a within-person, bottom-up effect). Top-down effects of PA were not significant in either study. These findings were robust when we controlled for competing top-down influences (e.g., sex, personality traits, self-esteem, body mass index, mental health symptoms, fatigue) and bottom-up influences (e.g., daily self-esteem, daily mental health symptoms, daily fatigue). Conclusions We concluded that SWL was impacted by people’s daily PA rather than their trait level of PA over time. These findings extend evidence that PA is a health behavior with important consequences for daily well-being and should be considered when developing national policies to enhance SWL. PMID:23088171

Efficient O(N) integration for all-electron electronic structure calculation using numeric basis functions

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

Havu, V.; Fritz Haber Institute of the Max Planck Society, Berlin; Blum, V.

2009-12-01

We consider the problem of developing O(N) scaling grid-based operations needed in many central operations when performing electronic structure calculations with numeric atom-centered orbitals as basis functions. We outline the overall formulation of localized algorithms, and specifically the creation of localized grid batches. The choice of the grid partitioning scheme plays an important role in the performance and memory consumption of the grid-based operations. Three different top-down partitioning methods are investigated, and compared with formally more rigorous yet much more expensive bottom-up algorithms. We show that a conceptually simple top-down grid partitioning scheme achieves essentially the same efficiency as themore » more rigorous bottom-up approaches.« less

Chemistry and temperature-assisted dehydrogenation of C60H30 molecules on TiO2(110) surfaces

NASA Astrophysics Data System (ADS)

Sánchez-Sánchez, Carlos; Martínez, José Ignacio; Lanzilotto, Valeria; Biddau, Giulio; Gómez-Lor, Berta; Pérez, Rubén; Floreano, Luca; López, María Francisca; Martín-Gago, José Ángel

2013-10-01

The thermal induced on-surface chemistry of large polycyclic aromatic hydrocarbons (PAHs) deposited on dielectric substrates is very rich and complex. We evidence temperature-assisted (cyclo)dehydrogenation reactions for C60H30 molecules and the subsequent bottom-up formation of assembled nanostructures, such as nanodomes, on the TiO2(110) surface. To this aim we have deposited, under ultra-high vacuum, a submonolayer coverage of C60H30 and studied, by a combination of experimental techniques (STM, XPS and NEXAFS) and theoretical methods, the different chemical on-surface interaction stages induced by the increasing temperature. We show that room temperature adsorbed molecules exhibit a weak interaction and freely diffuse on the surface, as previously reported for other aromatics. Nevertheless, a slight annealing induces a transition from this (meta)stable configuration into chemisorbed molecules. This adsorbate-surface interaction deforms the C60H30 molecular structure and quenches surface diffusion. Higher annealing temperatures lead to partial dehydrogenation, in which the molecule loses some of the hydrogen atoms and LUMO levels spread in the gap inducing a net total energy gain. Further annealing, up to around 750 K, leads to complete dehydrogenation. At these temperatures the fully dehydrogenated molecules link between them in a bottom-up coupling, forming nanodomes or fullerene-like monodisperse species readily on the dielectric surface. This work opens the door to the use of on-surface chemistry to generate new bottom-up tailored structures directly on high-K dielectric surfaces.The thermal induced on-surface chemistry of large polycyclic aromatic hydrocarbons (PAHs) deposited on dielectric substrates is very rich and complex. We evidence temperature-assisted (cyclo)dehydrogenation reactions for C60H30 molecules and the subsequent bottom-up formation of assembled nanostructures, such as nanodomes, on the TiO2(110) surface. To this aim we have deposited, under ultra-high vacuum, a submonolayer coverage of C60H30 and studied, by a combination of experimental techniques (STM, XPS and NEXAFS) and theoretical methods, the different chemical on-surface interaction stages induced by the increasing temperature. We show that room temperature adsorbed molecules exhibit a weak interaction and freely diffuse on the surface, as previously reported for other aromatics. Nevertheless, a slight annealing induces a transition from this (meta)stable configuration into chemisorbed molecules. This adsorbate-surface interaction deforms the C60H30 molecular structure and quenches surface diffusion. Higher annealing temperatures lead to partial dehydrogenation, in which the molecule loses some of the hydrogen atoms and LUMO levels spread in the gap inducing a net total energy gain. Further annealing, up to around 750 K, leads to complete dehydrogenation. At these temperatures the fully dehydrogenated molecules link between them in a bottom-up coupling, forming nanodomes or fullerene-like monodisperse species readily on the dielectric surface. This work opens the door to the use of on-surface chemistry to generate new bottom-up tailored structures directly on high-K dielectric surfaces. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr03706a

Steam bottoming cycle for an adiabatic diesel engine

NASA Technical Reports Server (NTRS)

Poulin, E.; Demier, R.; Krepchin, I.; Walker, D.

1984-01-01

Steam bottoming cycles using adiabatic diesel engine exhaust heat which projected substantial performance and economic benefits for long haul trucks were studied. Steam cycle and system component variables, system cost, size and performance were analyzed. An 811 K/6.90 MPa state of the art reciprocating expander steam system with a monotube boiler and radiator core condenser was selected for preliminary design. The costs of the diesel with bottoming system (TC/B) and a NASA specified turbocompound adiabatic diesel with aftercooling with the same total output were compared, the annual fuel savings less the added maintenance cost was determined to cover the increase initial cost of the TC/B system in a payback period of 2.3 years. Steam bottoming system freeze protection strategies were developed, technological advances required for improved system reliability are considered and the cost and performance of advanced systes are evaluated.

ULTRA: Underwater Localization for Transit and Reconnaissance Autonomy

NASA Technical Reports Server (NTRS)

Huntsberger, Terrance L.

2013-01-01

This software addresses the issue of underwater localization of unmanned vehicles and the inherent drift in their onboard sensors. The software gives a 2 to 3 factor of improvement over the state-of-the-art underwater localization algorithms. The software determines the localization (position, heading) of an AUV (autonomous underwater vehicle) in environments where there is no GPS signal. It accomplishes this using only the commanded position, onboard gyros/accelerometers, and the bathymetry of the bottom provided by an onboard sonar system. The software does not rely on an onboard bathymetry dataset, but instead incrementally determines the position of the AUV while mapping the bottom. In order to enable long-distance underwater navigation by AUVs, a localization method called ULTRA uses registration of the bathymetry data products produced by the onboard forward-looking sonar system for hazard avoidance during a transit to derive the motion and pose of the AUV in order to correct the DR (dead reckoning) estimates. The registration algorithm uses iterative point matching (IPM) combined with surface interpolation of the Iterative Closest Point (ICP) algorithm. This method was used previously at JPL for onboard unmanned ground vehicle localization, and has been optimized for efficient computational and memory use.

New Method to Synthesize Highly Active and Durable Chemically Ordered fct-PtCo Cathode Catalyst for PEMFCs.

PubMed

Jung, Won Suk; Popov, Branko N

2017-07-19

In the bottom-up synthesis strategy performed in this study, the Co-catalyzed pyrolysis of chelate-complex and activated carbon black at high temperatures triggers the graphitization reaction which introduces Co particles in the N-doped graphitic carbon matrix and immobilizes N-modified active sites for the oxygen reduction reaction (ORR) on the carbon surface. In this study, the Co particles encapsulated within the N-doped graphitic carbon shell diffuse up to the Pt surface under the polymer protective layer and forms a chemically ordered face-centered tetragonal (fct) Pt-Co catalyst PtCo/CCCS catalyst as evidenced by structural and compositional studies. The fct-structured PtCo/CCCS at low-Pt loading (0.1 mg Pt cm -2 ) shows 6% higher power density than that of the state-of-the-art commercial Pt/C catalyst. After the MEA durability test of 30 000 potential cycles, the performance loss of the catalyst is negligible. The electrochemical surface area loss is less than 40%, while that of commercial Pt/C is nearly 80%. After the accelerated stress test, the uniform catalyst distribution is retained and the mean particle size increases approximate 1 nm. The results obtained in this study indicated that highly stable compositional and structural properties of chemically ordered PtCo/CCCS catalyst contribute to its exceptional catalyst durability.

HIV Drug Resistance Early Warning Indicators in Namibia for Public Health Action

PubMed Central

Jonas, Anna; Gweshe, Justice; Siboleka, Milner; DeKlerk, Michael; Gawanab, Michael; Badi, Alfons; Sumbi, Victor; Pereko, Dawn; Blom, Abraham; Mwinga, Samson; Jordan, Michael R.; Jerger, Logan; Lau, Kiger; Hong, Steven Y.

2013-01-01

Background HIV drug resistance (HIVDR) testing is not routinely available in many resource-limited settings, therefore antiretroviral therapy (ART) program and site factors known to be associated with emergence of HIVDR should be monitored to optimize the quality of patient care and minimize the emergence of preventable HIVDR. Methods In 2010, Namibia selected five World Health Organization Early Warning Indicators (EWIs) and scaled-up monitoring from 9 to 33 ART sites: ART prescribing practices, Patients lost to follow-up (LTFU) at 12 months, Patients switched to a second-line regimen at 12 months, On-time antiretroviral (ARV) drug pick-up, and ARV drug-supply continuity. Results Records allowed reporting on three of the five selected EWIs. 22 of 33 (67%) sites met the target of 100% initiated on appropriate first-line regimens. 17 of 33 (52%) sites met the target of ≤20% LTFU. 15 of 33 (45%) sites met the target of 0% switched to a second-line regimen. Conclusions EWI monitoring directly resulted in public health action which will optimize the quality of care, specifically the strengthening of ART record systems, engagement of ART sites, and operational research for improved adherence assessment and ART patient defaulter tracing. PMID:23762406

Top-down and bottom-up neurodynamic evidence in patients with tinnitus.

PubMed

Hong, Sung Kwang; Park, Sejik; Ahn, Min-Hee; Min, Byoung-Kyong

2016-12-01

Although a peripheral auditory (bottom-up) deficit is an essential prerequisite for the generation of tinnitus, central cognitive (top-down) impairment has also been shown to be an inherent neuropathological mechanism. Using an auditory oddball paradigm (for top-down analyses) and a passive listening paradigm (for bottom-up analyses) while recording electroencephalograms (EEGs), we investigated whether top-down or bottom-up components were more critical in the neuropathology of tinnitus, independent of peripheral hearing loss. We observed significantly reduced P300 amplitudes (reflecting fundamental cognitive processes such as attention) and evoked theta power (reflecting top-down regulation in memory systems) for target stimuli at the tinnitus frequency of patients with tinnitus but without hearing loss. The contingent negative variation (reflecting top-down expectation of a subsequent event prior to stimulation) and N100 (reflecting auditory bottom-up selective attention) were different between the healthy and patient groups. Interestingly, when tinnitus patients were divided into two subgroups based on their P300 amplitudes, their P170 and N200 components, and annoyance and distress indices to their tinnitus sound were different. EEG theta-band power and its Granger causal neurodynamic results consistently support a double dissociation of these two groups in both top-down and bottom-up tasks. Directed cortical connectivity corroborates that the tinnitus network involves the anterior cingulate and the parahippocampal areas, where higher-order top-down control is generated. Together, our observations provide neurophysiological and neurodynamic evidence revealing a differential engagement of top-down impairment along with deficits in bottom-up processing in patients with tinnitus but without hearing loss. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Multi-scale modelling of elastic moduli of trabecular bone

PubMed Central

Hamed, Elham; Jasiuk, Iwona; Yoo, Andrew; Lee, YikHan; Liszka, Tadeusz

2012-01-01

We model trabecular bone as a nanocomposite material with hierarchical structure and predict its elastic properties at different structural scales. The analysis involves a bottom-up multi-scale approach, starting with nanoscale (mineralized collagen fibril) and moving up the scales to sub-microscale (single lamella), microscale (single trabecula) and mesoscale (trabecular bone) levels. Continuum micromechanics methods, composite materials laminate theory and finite-element methods are used in the analysis. Good agreement is found between theoretical and experimental results. PMID:22279160

What is Bottom-Up and What is Top-Down in Predictive Coding?

PubMed Central

Rauss, Karsten; Pourtois, Gilles

2013-01-01

Everyone knows what bottom-up is, and how it is different from top-down. At least one is tempted to think so, given that both terms are ubiquitously used, but only rarely defined in the psychology and neuroscience literature. In this review, we highlight the problems and limitations of our current understanding of bottom-up and top-down processes, and we propose a reformulation of this distinction in terms of predictive coding. PMID:23730295

Emotional face expression modulates occipital-frontal effective connectivity during memory formation in a bottom-up fashion.

PubMed

Xiu, Daiming; Geiger, Maximilian J; Klaver, Peter

2015-01-01

This study investigated the role of bottom-up and top-down neural mechanisms in the processing of emotional face expression during memory formation. Functional brain imaging data was acquired during incidental learning of positive ("happy"), neutral and negative ("angry" or "fearful") faces. Dynamic Causal Modeling (DCM) was applied on the functional magnetic resonance imaging (fMRI) data to characterize effective connectivity within a brain network involving face perception (inferior occipital gyrus and fusiform gyrus) and successful memory formation related areas (hippocampus, superior parietal lobule, amygdala, and orbitofrontal cortex). The bottom-up models assumed processing of emotional face expression along feed forward pathways to the orbitofrontal cortex. The top-down models assumed that the orbitofrontal cortex processed emotional valence and mediated connections to the hippocampus. A subsequent recognition memory test showed an effect of negative emotion on the response bias, but not on memory performance. Our DCM findings showed that the bottom-up model family of effective connectivity best explained the data across all subjects and specified that emotion affected most bottom-up connections to the orbitofrontal cortex, especially from the occipital visual cortex and superior parietal lobule. Of those pathways to the orbitofrontal cortex the connection from the inferior occipital gyrus correlated with memory performance independently of valence. We suggest that bottom-up neural mechanisms support effects of emotional face expression and memory formation in a parallel and partially overlapping fashion.

Estimated Costs for Delivery of HIV Antiretroviral Therapy to Individuals with CD4+ T-Cell Counts >350 cells/uL in Rural Uganda

PubMed Central

Jain, Vivek; Chang, Wei; Byonanebye, Dathan M.; Owaraganise, Asiphas; Twinomuhwezi, Ellon; Amanyire, Gideon; Black, Douglas; Marseille, Elliot; Kamya, Moses R.; Havlir, Diane V.; Kahn, James G.

2015-01-01

Background Evidence favoring earlier HIV ART initiation at high CD4+ T-cell counts (CD4>350/uL) has grown, and guidelines now recommend earlier HIV treatment. However, the cost of providing ART to individuals with CD4>350 in Sub-Saharan Africa has not been well estimated. This remains a major barrier to optimal global cost projections for accelerating the scale-up of ART. Our objective was to compute costs of ART delivery to high CD4+count individuals in a typical rural Ugandan health center-based HIV clinic, and use these data to construct scenarios of efficient ART scale-up. Methods Within a clinical study evaluating streamlined ART delivery to 197 individuals with CD4+ cell counts >350 cells/uL (EARLI Study: NCT01479634) in Mbarara, Uganda, we performed a micro-costing analysis of administrative records, ART prices, and time-and-motion analysis of staff work patterns. We computed observed per-person-per-year (ppy) costs, and constructed models estimating costs under several increasingly efficient ART scale-up scenarios using local salaries, lowest drug prices, optimized patient loads, and inclusion of viral load (VL) testing. Findings Among 197 individuals enrolled in the EARLI Study, median pre-ART CD4+ cell count was 569/uL (IQR 451–716). Observed ART delivery cost was $628 ppy at steady state. Models using local salaries and only core laboratory tests estimated costs of $529/$445 ppy (+/-VL testing, respectively). Models with lower salaries, lowest ART prices, and optimized healthcare worker schedules reduced costs by $100–200 ppy. Costs in a maximally efficient scale-up model were $320/$236 ppy (+/- VL testing). This included $39 for personnel, $106 for ART, $130/$46 for laboratory tests, and $46 for administrative/other costs. A key limitation of this study is its derivation and extrapolation of costs from one large rural treatment program of high CD4+ count individuals. Conclusions In a Ugandan HIV clinic, ART delivery costs—including VL testing—for individuals with CD4>350 were similar to estimates from high-efficiency programs. In higher efficiency scale-up models, costs were substantially lower. These favorable costs may be achieved because high CD4+ count patients are often asymptomatic, facilitating more efficient streamlined ART delivery. Our work provides a framework for calculating costs of efficient ART scale-up models using accessible data from specific programs and regions. PMID:26632823

Human resources for health strategies adopted by providers in resource-limited settings to sustain long-term delivery of ART: a mixed-methods study from Uganda.

PubMed

Zakumumpa, Henry; Taiwo, Modupe Oladunni; Muganzi, Alex; Ssengooba, Freddie

2016-10-19

Human resources for health (HRH) constraints are a major barrier to the sustainability of antiretroviral therapy (ART) scale-up programs in Sub-Saharan Africa. Many prior approaches to HRH constraints have taken a top-down trend of generalized global strategies and policy guidelines. The objective of the study was to examine the human resources for health strategies adopted by front-line providers in Uganda to sustain ART delivery beyond the initial ART scale-up phase between 2004 and 2009. A two-phase mixed-methods approach was adopted. In the first phase, a survey of a nationally representative sample of health facilities (n = 195) across Uganda was conducted. The second phase involved in-depth interviews (n = 36) with ART clinic managers and staff of 6 of the 195 health facilities purposively selected from the first study phase. Quantitative data was analysed based on descriptive statistics, and qualitative data was analysed by coding and thematic analysis. The identified strategies were categorized into five themes: (1) providing monetary and non-monetary incentives to health workers on busy ART clinic days; (2) workload reduction through spacing ART clinic appointments; (3) adopting training workshops in ART management as a motivation strategy for health workers; (4) adopting non-physician-centred staffing models; and (5) devising ART program leadership styles that enhanced health worker commitment. Facility-level strategies for responding to HRH constraints are feasible and can contribute to efforts to increase country ownership of HIV programs in resource-limited settings. Consideration of the human resources for health strategies identified in the study by ART program planners and managers could enhance the long-term sustainment of ART programs by providers in resource-limited settings.

A photofunctional bottom-up bis(dipyrrinato)zinc(II) complex nanosheet

PubMed Central

Sakamoto, Ryota; Hoshiko, Ken; Liu, Qian; Yagi, Toshiki; Nagayama, Tatsuhiro; Kusaka, Shinpei; Tsuchiya, Mizuho; Kitagawa, Yasutaka; Wong, Wai-Yeung; Nishihara, Hiroshi

2015-01-01

Two-dimensional polymeric nanosheets have recently gained much attention, particularly top-down nanosheets such as graphene and metal chalcogenides originating from bulk-layered mother materials. Although molecule-based bottom-up nanosheets manufactured directly from molecular components can exhibit greater structural diversity than top-down nanosheets, the bottom-up nanosheets reported thus far lack useful functionalities. Here we show the design and synthesis of a bottom-up nanosheet featuring a photoactive bis(dipyrrinato)zinc(II) complex motif. A liquid/liquid interfacial synthesis between a three-way dipyrrin ligand and zinc(II) ions results in a multi-layer nanosheet, whereas an air/liquid interfacial reaction produces a single-layer or few-layer nanosheet with domain sizes of >10 μm on one side. The bis(dipyrrinato)zinc(II) metal complex nanosheet is easy to deposit on various substrates using the Langmuir–Schäfer process. The nanosheet deposited on a transparent SnO2 electrode functions as a photoanode in a photoelectric conversion system, and is thus the first photofunctional bottom-up nanosheet. PMID:25831973

Vulnerability Assessment of Water Supply Systems: Status, Gaps and Opportunities

NASA Astrophysics Data System (ADS)

Wheater, H. S.

2015-12-01

Conventional frameworks for assessing the impacts of climate change on water resource systems use cascades of climate and hydrological models to provide 'top-down' projections of future water availability, but these are subject to high uncertainty and are model and scenario-specific. Hence there has been recent interest in 'bottom-up' frameworks, which aim to evaluate system vulnerability to change in the context of possible future climate and/or hydrological conditions. Such vulnerability assessments are generic, and can be combined with updated information from top-down assessments as they become available. While some vulnerability methods use hydrological models to estimate water availability, fully bottom-up schemes have recently been proposed that directly map system vulnerability as a function of feasible changes in water supply characteristics. These use stochastic algorithms, based on reconstruction or reshuffling methods, by which multiple water supply realizations can be generated under feasible ranges of change in water supply conditions. The paper reports recent successes, and points to areas of future improvement. Advances in stochastic modeling and optimization can address some technical limitations in flow reconstruction, while various data mining and system identification techniques can provide possibilities to better condition realizations for consistency with top-down scenarios. Finally, we show that probabilistic and Bayesian frameworks together can provide a potential basis to combine information obtained from fully bottom-up analyses with projections available from climate and/or hydrological models in a fully integrated risk assessment framework for deep uncertainty.

A reversed-phase capillary ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) method for comprehensive top-down/bottom-up lipid profiling

PubMed Central

Gao, Xiaoli; Zhang, Qibin; Meng, Da; Issac, Giorgis; Zhao, Rui; Fillmore, Thomas L.; Chu, Rosey K.; Zhou, Jianying; Tang, Keqi; Hu, Zeping; Moore, Ronald J.; Smith, Richard D.; Katze, Michael G.; Metz, Thomas O.

2012-01-01

Lipidomics is a critical part of metabolomics and aims to study all the lipids within a living system. We present here the development and evaluation of a sensitive capillary UPLC-MS method for comprehensive top-down/bottom-up lipid profiling. Three different stationary phases were evaluated in terms of peak capacity, linearity, reproducibility, and limit of quantification (LOQ) using a mixture of lipid standards representative of the lipidome. The relative standard deviations of the retention times and peak abundances of the lipid standards were 0.29% and 7.7%, respectively, when using the optimized method. The linearity was acceptable at >0.99 over 3 orders of magnitude, and the LOQs were sub-fmol. To demonstrate the performance of the method in the analysis of complex samples, we analyzed lipids extracted from a human cell line, rat plasma, and a model human skin tissue, identifying 446, 444, and 370 unique lipids, respectively. Overall, the method provided either higher coverage of the lipidome, greater measurement sensitivity, or both, when compared to other approaches of global, untargeted lipid profiling based on chromatography coupled with MS. PMID:22354571

Arts on prescription: a qualitative outcomes study.

PubMed

Stickley, T; Eades, M

2013-08-01

In recent years, participatory community-based arts activities have become a recognized and regarded method for promoting mental health. In the UK, Arts on Prescription services have emerged as a prominent form of such social prescribing. This follow-up study reports on the findings from interviews conducted with participants in an Arts on Prescription programme two years after previous interviews to assess levels of 'distance travelled'. This follow-up study used a qualitative interview method amongst participants of an Arts on Prescription programme of work. Ten qualitative one-to-one interviews were conducted in community-based arts venues. Each participant was currently using or had used mental health services, and had been interviewed two years earlier. Interviews were digitally recorded, transcribed and analysed. For each of the 10 participants, a lengthy attendance of Arts on Prescription had acted as a catalyst for positive change. Participants reported increased self-confidence, improved social and communication skills, and increased motivation and aspiration. An analysis of each of the claims made by participants enabled them to be grouped according to emerging themes: education: practical and aspirational achievements; broadened horizons: accessing new worlds; assuming and sustaining new identities; and social and relational perceptions. Both hard and soft outcomes were identifiable, but most were soft outcomes. Follow-up data indicating progress varied between respondents. Whilst hard outcomes could be identified in individual cases, the unifying factors across the sample were found predominately in the realm of soft outcomes. These soft outcomes, such as raised confidence and self-esteem, facilitated the hard outcomes such as educational achievement and voluntary work. Copyright © 2013 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

Perception and predictors of quality of life among HIV patients attending art clinics in northwest Ethiopia: a prospective longitudinal study.

PubMed

Wubshet, Mamo; Berhane, Yemane; Worku, Alemayehu; Kebede, Yigzaw

2014-07-01

In treating HIV as a chronic disease, monitoring changes of quality of life of patient's overtime is important for clinicians and policy makers. However, to our knowledge little research attention has been directed towards examining the longitudinal change of quality of life overtime in sub-Saharan Africa. To examine longitudinal changes in quality of life among patients initiated ART METHOD: A prospective longitudinal follow-up study was conducted from December 2009 to August 2011 to evaluate the changes in quality of life and how this relates with baseline socio-demographic and clinical characteristics among consecutive adult ART naïve patients attending ART clinic. Quality of life was measured by WHOQOL-HIV BREF. All quality of life domain scores improved significantly during 12 month follow-up in the ART program. At each follow-up visit, scores were significantly higher than baseline scores (p < 0.001). Predictors of improved quality of life were male gender, disclosure of HIV status, starting ART at higher CD4, > 200 cells/μL, and good baseline overall quality of life, whereas predictors of poor quality of life were starting ART with advanced disease stage and tuberculosis co-infection. This study demonstrated that the quality of life improved overtime for HIV-infected individuals receiving ART which is consistent with previous studies. It also provided information regarding the predictive effects of baseline socio-demographic and clinical factors on the changes in quality of life at the 12-month follow-up time. The finding of the study has implications of starting ART at a higher CD4 and early stage of the disease for better quality of life outcomes.

The cognitive benefits of interacting with nature.

PubMed

Berman, Marc G; Jonides, John; Kaplan, Stephen

2008-12-01

We compare the restorative effects on cognitive functioning of interactions with natural versus urban environments. Attention restoration theory (ART) provides an analysis of the kinds of environments that lead to improvements in directed-attention abilities. Nature, which is filled with intriguing stimuli, modestly grabs attention in a bottom-up fashion, allowing top-down directed-attention abilities a chance to replenish. Unlike natural environments, urban environments are filled with stimulation that captures attention dramatically and additionally requires directed attention (e.g., to avoid being hit by a car), making them less restorative. We present two experiments that show that walking in nature or viewing pictures of nature can improve directed-attention abilities as measured with a backwards digit-span task and the Attention Network Task, thus validating attention restoration theory.

Native Skywatchers: Kapemni. As it is Above, It is Below. . . A Hands-On STEM + Art + Culture Experience.

NASA Astrophysics Data System (ADS)

Lee, A. S.

2015-11-01

In D(L)akota star knowledge there is one overlying idea, “kapemni.” Imagine two tipis lined up vertically so that the tops are touching. The top triangle represents the spirit world or the star world; the bottom triangle is the material world or physical world. The idea is when a mirroring of the star world is created with what's happening on Earth (or vice versa), a doorway is created and opened between the worlds. There is a flow. This workshop will use the D(L)akota star map, “Dakota Makọce Wicaƞngḣpi Wowapi,” to teach participants the native constellations that are visible in tonight's sky. Then participants will visually communicate their connection to the stars and the seasons.

Composite S-layer lipid structures

PubMed Central

Schuster, Bernhard; Sleytr, Uwe B.

2010-01-01

Designing and utilization of biomimetic membrane systems generated by bottom-up processes is a rapidly growing scientific and engineering field. Elucidation of the supramolecular construction principle of archaeal cell envelopes composed of S-layer stabilized lipid membranes led to new strategies for generating highly stable functional lipid membranes at meso- and macroscopic scale. In this review, we provide a state of the art survey how S-layer proteins, lipids, and polysaccharides may be used as basic building blocks for the assembly of S-layer supported lipid membranes. These biomimetic membrane systems are distinguished by a nanopatterned fluidity, enhanced stability and longevity and thus, provide a dedicated reconstitution matrix for membrane-active peptides and transmembrane proteins. Exciting areas for application of composite S-layer membrane systems concern sensor systems involving specific membrane functions. PMID:19303933

Improved survival in HIV treatment programs in Asia

PubMed Central

De La Mata, Nicole L; Kumarasamy, Nagalingeswaran; Khol, Vohith; Ng, Oon Tek; Van Nguyen, Kinh; Merati, Tuti Parwati; Pham, Thuy Thanh; Lee, Man Po; Durier, Nicolas; Law, Matthew

2016-01-01

Background Antiretroviral treatment (ART) for HIV-positive patients has expanded rapidly in Asia over the last ten years. Our study aimed to describe the time trends and risk factors for overall survival in patients receiving first-line ART in Asia. Methods We included HIV-positive adult patients who initiated ART between 2003–2013 (n=16 546), from seven sites across six Asia-Pacific countries. Patient follow-up was to May 2014. We compared survival for each country and overall by time period of ART initiation using Kaplan-Meier curves. Factors associated with mortality were assessed using Cox regression, stratified by site. We also summarized first-line ART regimens, CD4 count at ART initiation, and CD4 and HIV viral load testing frequencies. Results There were 880 deaths observed over 54 532 person-years of follow-up, a crude rate of 1.61 (1.51, 1.72) per 100 person-years. Survival significantly improved in more recent years of ART initiation. The survival probabilities at 4 years follow-up for those initiating ART in 2003–05 was 92.1%, 2006–09 was 94.3% and 2010–2013 was 94.5% (p<0.001). Factors associated with higher mortality risk included initiating ART in earlier time periods, older age, male sex, injecting drug use as HIV exposure and lower pre-ART CD4 count. Concurrent with improved survival was increased tenofovir use, ART initiation at higher CD4 counts, and greater monitoring of CD4 and HIV viral load. Conclusions Our results suggest that HIV-positive patients from Asia have improved survival in more recent years of ART initiation. This is likely a consequence of improvements in treatment and, patient management and monitoring over time. PMID:26961354

On the determination of the carbon balance of continents (Vladimir Ivanovich Vernadsky Medal Lecture)

NASA Astrophysics Data System (ADS)

Dolman, Albertus J. Han

2013-04-01

The carbon balance of regions, the size of continents, can be determined, albeit with significant uncertainty, by combining several bottom up and top down methods. The bottom up methods use eddy covariance techniques, biometric inventory measurements and modeling, while the top down methods use atmospheric observations and inverse models. There has been considerable progress in the last few years in determining these balances through more or less standard protocols, as highlighted for instance by studies of the REgional Carbon Cycle Assessment and Processes (RECAPP) project of the Global Carbon Project. Important areas where uncertainty creeps in are the scaling of point measurements in the bottom up methods, the sparseness of the observation network and the role of model and other errors in the inversion methods. Typically these balances hold for periods of several years. They therefore do not resolve the impact of anomalies in weather and climate directly. The role of management in these balances also differs for different continents. For instance in Europe management plays a strong role in the carbon balance, whereas for the Russian continent this is less important. Management in the European carbon balance may potentially override climatically driven variability. In contrast, for Russia, the importance of the role of forest is paramount, but there the vulnerability of the Arctic regions and permafrost is a key uncertainty for future behaviour. I hope to show the importance of these different aspects of the terrestrial carbon balance by comparing the two continents, and also discuss the significant uncertainty we still face in determining the carbon budgets of large areas. I will argue that we need to get a clearer picture of the role of management in these budgets, but also of the time variability of the budgets to be able to determine the impact of anomalous weather and the vulnerability in a future climate.

Optimization of synthesis process of thermally-responsive poly-n-isopropylacrylamide nanoparticles for controlled release of antimicrobial hydrophobic compounds

NASA Astrophysics Data System (ADS)

Hill, Laura E.; Gomes, Carmen L.

2014-12-01

The goal of this study was to develop an effective method to synthesize poly-n-isopropylacrylamide (PNIPAAM) nanoparticles with entrapped cinnamon bark extract (CBE) to improve its delivery to foodborne pathogens and control its release with temperature stimuli. CBE was used as a model for hydrophobic natural antimicrobials. A top-down procedure using crosslinked PNIPAAM was compared to a bottom-up procedure using NIPAAM monomer. Both processes relied on self-assembly of the molecules into micelles around the CBE at 40 °C. Processing conditions were compared including homogenization time of the polymer, hydration time prior to homogenization, lyophilization, and the effect of particle ultrafiltration. The top-down versus bottom-up synthesis methods yielded particles with significantly different characteristics, especially their release profiles and antimicrobial activities. The synthesis methods affected particle size, with the bottom-up procedure resulting in smaller (P < 0.05) diameters than the top-down procedure. The controlled release profile of CBE from nanoparticles was dependent on the release media temperature. A faster, burst release was observed at 40 °C and a slower, more sustained release was observed at lower temperatures. PNIPAAM particles containing CBE were analyzed for their antimicrobial activity against Salmonella enterica serovar Typhimurium LT2 and Listeria monocytogenes Scott A. The PNIPAAM particles synthesized via the top-down procedure had a much faster release, which led to a greater (P < 0.05) antimicrobial activity. Both of the top-down nanoparticles performed similarly, therefore the 7 min homogenization time nanoparticles would be the best for this application, as the process time is shorter and little improvement was seen by using a slightly longer homogenization.

Structurally Defined 3D Nanographene Assemblies via Bottom-Up Chemical Synthesis for Highly Efficient Lithium Storage

DOE PAGES

Yen, Hung-Ju; Tsai, Hsinhan; Zhou, Ming; ...

2016-10-10

In this paper, functionalized 3D nanographenes with controlled electronic properties have been synthesized through a multistep organic synthesis method and are further used as promising anode materials for lithium-ion batteries, exhibiting a much increased capacity (up to 950 mAh g -1), three times higher than that of the graphite anode (372 mAh g -1).

11th Annual CMMI Technology Conference and User Group

DTIC Science & Technology

2011-11-17

Examples of triggers may include: – Cost performance – Schedule performance – Results of management reviews – Occurrence of the risk • as a...Analysis (PHA) – Method 3 – Through bottom- up analysis of design data (e.g., flow diagrams, Failure Mode Effects and Criticality Analysis (FMECA...of formal reviews and the setting up of delta or follow- up reviews can be used to give the organization more places to look at the products as they

Micropatterning stretched and aligned DNA using microfluidics and surface patterning for applications in hybridization-mediated templated assembly of nanostructures

NASA Astrophysics Data System (ADS)

Carbeck, Jeffrey; Petit, Cecilia

2004-03-01

Current efforts in nanotechnology use one of two basic approaches: top-down fabrication and bottom-up assembly. Top-down strategies use lithography and contact printing to create patterned surfaces and microfluidic channels that, in turn, can corral and organize nanoscale structures. Bottom-up approaches use templates to direct the assembly of atoms, molecules, and nanoparticles through molecular recognition. The goal of this work is to integrate these strategies by first patterning and orienting DNA molecules through top-down tools so that single DNA chains can then serve as templates for the bottom-up construction of hetero-structures composed of proteins and nanoparticles, both metallic and semi-conducting. The first part of this talk focuses on the top-down strategies used to create microscopic patterns of stretched and aligned molecules of DNA. Specifically, it presents a new method in which molecular combing -- a process by which molecules are deposited and stretched onto a surface by the passage of an air-water interface -- is performed in microchannels. This approach demonstrates that the shape and motion of this interface serve as an effective local field directing the chains dynamically as they are stretched onto the surface. The geometry of the microchannel directs the placement of the DNA molecules, while the geometry of the air-water interface directs the local orientation and curvature of the molecules. This ability to control both the placement and orientation of chains has implication for the use of this technique in genetic analysis and in the bottom up approach to nanofabrication.The second half of this talk presents our bottom-up strategy, which allows placement of nanoparticles along individual DNA chains with a theoretical resolution of less than 1 nm. Specifically, we demonstrate the sequence-specific patterning of nanoparticles via the hybridization of functionalized complementary probes to surface-bound chains of double-stranded DNA. Using this technique, we demonstrate the ability to assemble metals, semiconductors, and a composite of both on a single molecule.

Biomimetic proteolipid vesicles for targeting inflamed tissues

NASA Astrophysics Data System (ADS)

Molinaro, R.; Corbo, C.; Martinez, J. O.; Taraballi, F.; Evangelopoulos, M.; Minardi, S.; Yazdi, I. K.; Zhao, P.; De Rosa, E.; Sherman, M. B.; de Vita, A.; Toledano Furman, N. E.; Wang, X.; Parodi, A.; Tasciotti, E.

2016-09-01

A multitude of micro- and nanoparticles have been developed to improve the delivery of systemically administered pharmaceuticals, which are subject to a number of biological barriers that limit their optimal biodistribution. Bioinspired drug-delivery carriers formulated by bottom-up or top-down strategies have emerged as an alternative approach to evade the mononuclear phagocytic system and facilitate transport across the endothelial vessel wall. Here, we describe a method that leverages the advantages of bottom-up and top-down strategies to incorporate proteins derived from the leukocyte plasma membrane into lipid nanoparticles. The resulting proteolipid vesicles--which we refer to as leukosomes--retained the versatility and physicochemical properties typical of liposomal formulations, preferentially targeted inflamed vasculature, enabled the selective and effective delivery of dexamethasone to inflamed tissues, and reduced phlogosis in a localized model of inflammation.

Pressurized Pepsin Digestion in Proteomics: An Automatable Alternative to Trypsin for Integrated Top-down Bottom-up Proteomics

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

Lopez-Ferrer, Daniel; Petritis, Konstantinos; Robinson, Errol W.

2011-02-01

Integrated top-down bottom-up proteomics combined with online digestion has great potential to improve the characterization of protein isoforms in biological systems and is amendable to highthroughput proteomics experiments. Bottom-up proteomics ultimately provides the peptide sequences derived from the tandem MS analyses of peptides after the proteome has been digested. Top-down proteomics conversely entails the MS analyses of intact proteins for more effective characterization of genetic variations and/or post-translational modifications (PTMs). Herein, we describe recent efforts towards efficient integration of bottom-up and top-down LCMS based proteomic strategies. Since most proteomic platforms (i.e. LC systems) operate in acidic environments, we exploited themore » compatibility of the pepsin (i.e. the enzyme’s natural acidic activity) for the integration of bottom-up and top-down proteomics. Pressure enhanced pepsin digestions were successfully performed and characterized with several standard proteins in either an offline mode using a Barocycler or an online mode using a modified high pressure LC system referred to as a fast online digestion system (FOLDS). FOLDS was tested using pepsin and a whole microbial proteome, and the results compared against traditional trypsin digestions on the same platform. Additionally, FOLDS was integrated with a RePlay configuration to demonstrate an ultra-rapid integrated bottom-up top-down proteomic strategy employing a standard mixture of proteins and a monkey pox virus proteome.« less

Combined contributions of feedforward and feedback inputs to bottom-up attention

PubMed Central

Khorsand, Peyman; Moore, Tirin; Soltani, Alireza

2015-01-01

In order to deal with a large amount of information carried by visual inputs entering the brain at any given point in time, the brain swiftly uses the same inputs to enhance processing in one part of visual field at the expense of the others. These processes, collectively called bottom-up attentional selection, are assumed to solely rely on feedforward processing of the external inputs, as it is implied by the nomenclature. Nevertheless, evidence from recent experimental and modeling studies points to the role of feedback in bottom-up attention. Here, we review behavioral and neural evidence that feedback inputs are important for the formation of signals that could guide attentional selection based on exogenous inputs. Moreover, we review results from a modeling study elucidating mechanisms underlying the emergence of these signals in successive layers of neural populations and how they depend on feedback from higher visual areas. We use these results to interpret and discuss more recent findings that can further unravel feedforward and feedback neural mechanisms underlying bottom-up attention. We argue that while it is descriptively useful to separate feedforward and feedback processes underlying bottom-up attention, these processes cannot be mechanistically separated into two successive stages as they occur at almost the same time and affect neural activity within the same brain areas using similar neural mechanisms. Therefore, understanding the interaction and integration of feedforward and feedback inputs is crucial for better understanding of bottom-up attention. PMID:25784883

Trophic cascades of bottom-up and top-down forcing on nutrients and plankton in the Kattegat, evaluated by modelling

NASA Astrophysics Data System (ADS)

Petersen, Marcell Elo; Maar, Marie; Larsen, Janus; Møller, Eva Friis; Hansen, Per Juel

2017-05-01

The aim of the study was to investigate the relative importance of bottom-up and top-down forcing on trophic cascades in the pelagic food-web and the implications for water quality indicators (summer phytoplankton biomass and winter nutrients) in relation to management. The 3D ecological model ERGOM was validated and applied in a local set-up of the Kattegat, Denmark, using the off-line Flexsem framework. The model scenarios were conducted by changing the forcing by ± 20% of nutrient inputs (bottom-up) and mesozooplankton mortality (top-down), and both types of forcing combined. The model results showed that cascading effects operated differently depending on the forcing type. In the single-forcing bottom-up scenarios, the cascade directions were in the same direction as the forcing. For scenarios involving top-down, there was a skipped-level-transmission in the trophic responses that was either attenuated or amplified at different trophic levels. On a seasonal scale, bottom-up forcing showed strongest response during winter-spring for DIN and Chl a concentrations, whereas top-down forcing had the highest cascade strength during summer for Chl a concentrations and microzooplankton biomass. On annual basis, the system was more bottom-up than top-down controlled. Microzooplankton was found to play an important role in the pelagic food web as mediator of nutrient and energy fluxes. This study demonstrated that the best scenario for improved water quality was a combined reduction in nutrient input and mesozooplankton mortality calling for the need of an integrated management of marine areas exploited by human activities.

Network Learning for Educational Change. Professional Learning

ERIC Educational Resources Information Center

Veugelers, Wiel, Ed.; O'Hair, Mary John, Ed.

2005-01-01

School-university networks are becoming an important method to enhance educational renewal and student achievement. Networks go beyond tensions of top-down versus bottom-up, school development and professional development of individuals, theory and practice, and formal and informal organizational structures. The theoretical base of networking…

Publisher Correction: Bottom-up linking of carbon markets under far-sighted cap coordination and reversibility

NASA Astrophysics Data System (ADS)

Heitzig, Jobst; Kornek, Ulrike

2018-06-01

In the PDF version of this Article originally published, in equation (6) gi' was incorrectly formatted as gi', and at the end of the Methods section wi was incorrectly formatted as wi. These have now been corrected.

Bottom-up and top-down emotion generation: implications for emotion regulation

PubMed Central

Misra, Supriya; Prasad, Aditya K.; Pereira, Sean C.; Gross, James J.

2012-01-01

Emotion regulation plays a crucial role in adaptive functioning and mounting evidence suggests that some emotion regulation strategies are often more effective than others. However, little attention has been paid to the different ways emotions can be generated: from the ‘bottom-up’ (in response to inherently emotional perceptual properties of the stimulus) or ‘top-down’ (in response to cognitive evaluations). Based on a process priming principle, we hypothesized that mode of emotion generation would interact with subsequent emotion regulation. Specifically, we predicted that top-down emotions would be more successfully regulated by a top-down regulation strategy than bottom-up emotions. To test this hypothesis, we induced bottom-up and top-down emotions, and asked participants to decrease the negative impact of these emotions using cognitive reappraisal. We observed the predicted interaction between generation and regulation in two measures of emotional responding. As measured by self-reported affect, cognitive reappraisal was more successful on top-down generated emotions than bottom-up generated emotions. Neurally, reappraisal of bottom-up generated emotions resulted in a paradoxical increase of amygdala activity. This interaction between mode of emotion generation and subsequent regulation should be taken into account when comparing of the efficacy of different types of emotion regulation, as well as when reappraisal is used to treat different types of clinical disorders. PMID:21296865

Solid-State Nanopore.

PubMed

Yuan, Zhishan; Wang, Chengyong; Yi, Xin; Ni, Zhonghua; Chen, Yunfei; Li, Tie

2018-02-20

Solid-state nanopore has captured the attention of many researchers due to its characteristic of nanoscale. Now, different fabrication methods have been reported, which can be summarized into two broad categories: "top-down" etching technology and "bottom-up" shrinkage technology. Ion track etching method, mask etching method chemical solution etching method, and high-energy particle etching and shrinkage method are exhibited in this report. Besides, we also discussed applications of solid-state nanopore fabrication technology in DNA sequencing, protein detection, and energy conversion.

Solid-State Nanopore

NASA Astrophysics Data System (ADS)

Yuan, Zhishan; Wang, Chengyong; Yi, Xin; Ni, Zhonghua; Chen, Yunfei; Li, Tie

2018-02-01

Solid-state nanopore has captured the attention of many researchers due to its characteristic of nanoscale. Now, different fabrication methods have been reported, which can be summarized into two broad categories: "top-down" etching technology and "bottom-up" shrinkage technology. Ion track etching method, mask etching method chemical solution etching method, and high-energy particle etching and shrinkage method are exhibited in this report. Besides, we also discussed applications of solid-state nanopore fabrication technology in DNA sequencing, protein detection, and energy conversion.

An integrative top-down and bottom-up qualitative model construction framework for exploration of biochemical systems.

PubMed

Wu, Zujian; Pang, Wei; Coghill, George M

Computational modelling of biochemical systems based on top-down and bottom-up approaches has been well studied over the last decade. In this research, after illustrating how to generate atomic components by a set of given reactants and two user pre-defined component patterns, we propose an integrative top-down and bottom-up modelling approach for stepwise qualitative exploration of interactions among reactants in biochemical systems. Evolution strategy is applied to the top-down modelling approach to compose models, and simulated annealing is employed in the bottom-up modelling approach to explore potential interactions based on models constructed from the top-down modelling process. Both the top-down and bottom-up approaches support stepwise modular addition or subtraction for the model evolution. Experimental results indicate that our modelling approach is feasible to learn the relationships among biochemical reactants qualitatively. In addition, hidden reactants of the target biochemical system can be obtained by generating complex reactants in corresponding composed models. Moreover, qualitatively learned models with inferred reactants and alternative topologies can be used for further web-lab experimental investigations by biologists of interest, which may result in a better understanding of the system.

A combined bottom-up/top-down approach to prepare a sterile injectable nanosuspension.

PubMed

Hu, Xi; Chen, Xi; Zhang, Ling; Lin, Xia; Zhang, Yu; Tang, Xing; Wang, Yanjiao

2014-09-10

To prepare a uniform nanosuspension of strongly hydrophobic riboflavin laurate (RFL) allowing sterile filtration, physical modification (bottom-up) was combined with high-pressure homogenization (top-down) method. Unlike other bottom-up approaches, physical modification with surfactants (TPGS and PL-100) by lyophilization controlled crystallization and compensated for the poor wettability of RFL. On one hand, crystal growth and aggregation during freezing was restricted by a stabilizer-layer adsorbed on the drug surface by hydrophobic interaction. On the other hand, subsequent crystallization of drug in the sublimation process was limited to the interstitial spaces between solvent crystals. After lyophilization, modified drug with a smaller particle size and better wettability was obtained. When adding surfactant solution, water molecules passed between the hydrophilic groups of surface active molecules and activated the polymer chains allowing them to stretch into water. The coarse suspension was crushed into a nanosuspension (MP=162 nm) by high-pressure homogenization. For long term stability, lyophilization was applied again to solidify the nanosuspension (sorbitol as cryoprotectant). A slight crystal growth to about 600 nm was obtained to allow slow release for a sustained effect after muscular administration. Moreover, no paw-licking responses and very slight muscular inflammation demonstrated the excellent biocompatibility of this long-acting RFL injection. Copyright © 2014 Elsevier B.V. All rights reserved.

De novo protein sequencing by combining top-down and bottom-up tandem mass spectra.

PubMed

Liu, Xiaowen; Dekker, Lennard J M; Wu, Si; Vanduijn, Martijn M; Luider, Theo M; Tolić, Nikola; Kou, Qiang; Dvorkin, Mikhail; Alexandrova, Sonya; Vyatkina, Kira; Paša-Tolić, Ljiljana; Pevzner, Pavel A

2014-07-03

There are two approaches for de novo protein sequencing: Edman degradation and mass spectrometry (MS). Existing MS-based methods characterize a novel protein by assembling tandem mass spectra of overlapping peptides generated from multiple proteolytic digestions of the protein. Because each tandem mass spectrum covers only a short peptide of the target protein, the key to high coverage protein sequencing is to find spectral pairs from overlapping peptides in order to assemble tandem mass spectra to long ones. However, overlapping regions of peptides may be too short to be confidently identified. High-resolution mass spectrometers have become accessible to many laboratories. These mass spectrometers are capable of analyzing molecules of large mass values, boosting the development of top-down MS. Top-down tandem mass spectra cover whole proteins. However, top-down tandem mass spectra, even combined, rarely provide full ion fragmentation coverage of a protein. We propose an algorithm, TBNovo, for de novo protein sequencing by combining top-down and bottom-up MS. In TBNovo, a top-down tandem mass spectrum is utilized as a scaffold, and bottom-up tandem mass spectra are aligned to the scaffold to increase sequence coverage. Experiments on data sets of two proteins showed that TBNovo achieved high sequence coverage and high sequence accuracy.

The bottom-up approach to integrative validity: a new perspective for program evaluation.

PubMed

Chen, Huey T

2010-08-01

The Campbellian validity model and the traditional top-down approach to validity have had a profound influence on research and evaluation. That model includes the concepts of internal and external validity and within that model, the preeminence of internal validity as demonstrated in the top-down approach. Evaluators and researchers have, however, increasingly recognized that in an evaluation, the over-emphasis on internal validity reduces that evaluation's usefulness and contributes to the gulf between academic and practical communities regarding interventions. This article examines the limitations of the Campbellian validity model and the top-down approach and provides a comprehensive, alternative model, known as the integrative validity model for program evaluation. The integrative validity model includes the concept of viable validity, which is predicated on a bottom-up approach to validity. This approach better reflects stakeholders' evaluation views and concerns, makes external validity workable, and becomes therefore a preferable alternative for evaluation of health promotion/social betterment programs. The integrative validity model and the bottom-up approach enable evaluators to meet scientific and practical requirements, facilitate in advancing external validity, and gain a new perspective on methods. The new perspective also furnishes a balanced view of credible evidence, and offers an alternative perspective for funding. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

Alternative financing mechanisms for ART programs in health facilities in Uganda: a mixed-methods approach.

PubMed

Zakumumpa, Henry; Bennett, Sara; Ssengooba, Freddie

2017-01-23

Sub-Saharan Africa is heavily dependent on global health initiatives (GHIs) for funding antiretroviral therapy (ART) scale-up. There are indications that global investments for ART scale-up are flattening. It is unclear what new funding channels can bridge the funding gap for ART service delivery. Many previous studies have focused on domestic government spending and international funding especially from GHIs. The objective of this study was to identify the funding strategies adopted by health facilities in Uganda to sustain ART programs between 2004 and 2014 and to explore variations in financing mechanisms by ownership of health facility. A mixed-methods approach was employed. A survey of health facilities (N = 195) across Uganda which commenced ART delivery between 2004 and 2009 was conducted. Six health facilities were purposively selected for in-depth examination. Semi-structured interviews (N = 18) were conducted with ART Clinic managers (three from each of the six health facilities). Statistical analyses were performed in STATA (Version 12.0) and qualitative data were analyzed by coding and thematic analysis. Multiple funding sources for ART programs were common with 140 (72%) of the health facilities indicating at least two concurrent grants supporting ART service delivery between 2009 and 2014. Private philanthropic aid emerged as an important source of supplemental funding for ART service delivery. ART financing strategies were differentiated by ownership of health facility. Private not-for-profit providers were more externally-focused (multiple grants, philanthropic aid). For-profit providers were more client-oriented (fee-for-service, insurance schemes). Public facilities sought additional funding streams not dissimilar to other health facility ownership-types. Over the 10-year study period, health facilities in Uganda diversified funding sources for ART service delivery. The identified alternative funding mechanisms could reduce dependence on GHI funding and increase local ownership of HIV programs. Further research evaluating the potential contribution of the identified alternative financing mechanisms in bridging the global HIV funding gap is recommended.

The effects of urbanization on trophic interactions in a desert landscape

USDA-ARS?s Scientific Manuscript database

Background/Question/Methods: Trophic systems can be affected through top-down (predators) and bottom-up (resources) impacts. Human activity can alter trophic systems by causing predators to avoid areas (top-down) or by providing increased resources through irrigation and decorative plants that attra...

Not All Are Lost: Interrupted Laboratory Monitoring, Early Death, and Loss to Follow-Up (LTFU) in a Large South African Treatment Program

PubMed Central

Ahonkhai, Aima A.; Noubary, Farzad; Munro, Alison; Stark, Ruth; Wilke, Marisa; Freedberg, Kenneth A.; Wood, Robin; Losina, Elena

2012-01-01

Background Many HIV treatment programs in resource-limited settings are plagued by high rates of loss to follow-up (LTFU). Most studies have not distinguished between those who briefly interrupt, but return to care, and those more chronically lost to follow-up. Methods We conducted a retrospective cohort study of 11,397 adults initiating antiretroviral therapy (ART) in 71 Southern African Catholic Bishops Conference/Catholic Relief Services HIV treatment clinics between January 2004 and December 2008. We distinguished among patients with early death, within the first 7 months on ART; patients with interruptions in laboratory monitoring (ILM), defined as missing visits in the first 7 months on ART, but returning to care by 12 months; and those LTFU, defined as missing all follow-up visits in the first 12 months on ART. We used multilevel logistic regression models to determine patient and clinic-level characteristics associated with these outcomes. Results In the first year on ART, 60% of patients remained in care, 30% missed laboratory visits, and 10% suffered early death. Of the 3,194 patients who missed laboratory visits, 40% had ILM, resuming care by 12 months. After 12 months on ART, patients with ILM had a 30% increase in detectable viremia compared to those who remained in care. Risk of LTFU decreased with increasing enrollment year, and was lowest for patients who enrolled in 2008 compared to 2004 [OR 0.49, 95%CI 0.39–0.62]. Conclusions In a large community-based cohort in South Africa, nearly 30% of patients miss follow-up visits for CD4 monitoring in the first year after starting ART. Of those, 40% have ILM but return to clinic with worse virologic outcomes than those who remain in care. The risk of chronic LTFU decreased with enrollment year. As ART availability increases, interruptions in care may become more common, and should be accounted for in addressing program LTFU. PMID:22427925

Top-down Estimates of Greenhouse Gas Intensities and Emissions for Individual Oil Sands Facilities in Alberta Canada

NASA Astrophysics Data System (ADS)

Liggio, J.; Li, S. M.; Staebler, R. M.; Hayden, K. L.; Mittermeier, R. L.; McLaren, R.; Baray, S.; Darlington, A.; Worthy, D.; O'Brien, J.

2017-12-01

The oil sands (OS) region of Alberta contributes approximately 10% to Canada's overall anthropogenic greenhouse gas (GHG) emissions. Such emissions have traditionally been estimated through "bottom-up" methods which seek to account for all individual sources of GHGs within a given facility. However, it is recognized that bottom-up approaches for complex industrial facilities can be subject to uncertainties associated with incomplete or inaccurate emission factor and/or activity data. In order to quantify air pollutant emissions from oil sands activities an aircraft-based measurement campaign was performed in the summer of 2013. The aircraft measurements could also be used to quantify GHG emissions for comparison to the bottom up emissions estimates. Utilizing specific flight patterns, together with an emissions estimation algorithm and measurements of CO2 and methane, a "top-down" estimate of GHG intensities for several large surface mining operations was obtained. The results demonstrate that there is a wide variation in emissions intensities (≈80 - 220 kg CO2/barrel oil) across OS facilities, which in some cases agree with calculated intensities, and in other cases are larger than that estimated using industry reported GHG emission and oil production data. When translated to annual GHG emissions, the "top-down" approach results in a CO2 emission of approximately 41 Mega Tonnes (MT) CO2/year for the 4 OS facilities investigated, in contrast to the ≈26 MT CO2/year reported by industry. The results presented here highlight the importance of using "top-down" approaches as a complimentary method in evaluating GHG emissions from large industrial sources.

Variation and Defect Tolerance for Nano Crossbars

NASA Astrophysics Data System (ADS)

Tunc, Cihan

With the extreme shrinking in CMOS technology, quantum effects and manufacturing issues are getting more crucial. Hence, additional shrinking in CMOS feature size seems becoming more challenging, difficult, and costly. On the other hand, emerging nanotechnology has attracted many researchers since additional scaling down has been demonstrated by manufacturing nanowires, Carbon nanotubes as well as molecular switches using bottom-up manufacturing techniques. In addition to the progress in manufacturing, developments in architecture show that emerging nanoelectronic devices will be promising for the future system designs. Using nano crossbars, which are composed of two sets of perpendicular nanowires with programmable intersections, it is possible to implement logic functions. In addition, nano crossbars present some important features as regularity, reprogrammability, and interchangeability. Combining these features, researchers have presented different effective architectures. Although bottom-up nanofabrication can greatly reduce manufacturing costs, due to low controllability in the manufacturing process, some critical issues occur. Bottom- up nanofabrication process results in high variation compared to conventional top- down lithography used in CMOS technology. In addition, an increased failure rate is expected. Variation and defect tolerance methods used for conventional CMOS technology seem inadequate for adapting to emerging nano technology because the variation and the defect rate for emerging nano technology is much more than current CMOS technology. Therefore, variations and defect tolerance methods for emerging nano technology are necessary for a successful transition. In this work, in order to tolerate variations for crossbars, we introduce a framework that is established based on reprogrammability and interchangeability features of nano crossbars. This framework is shown to be applicable for both FET-based and diode-based nano crossbars. We present a characterization testing method which requires minimal number of test vectors. We formulate the variation optimization problem using Simulated Annealing with different optimization goals. Furthermore, we extend the framework for defect tolerance. Experimental results and comparison of proposed framework with exhaustive methods confirm its effectiveness for both variation and defect tolerance.

Efficient Research Design: Using Value-of-Information Analysis to Estimate the Optimal Mix of Top-down and Bottom-up Costing Approaches in an Economic Evaluation alongside a Clinical Trial.

PubMed

Wilson, Edward C F; Mugford, Miranda; Barton, Garry; Shepstone, Lee

2016-04-01

In designing economic evaluations alongside clinical trials, analysts are frequently faced with alternative methods of collecting the same data, the extremes being top-down ("gross costing") and bottom-up ("micro-costing") approaches. A priori, bottom-up approaches may be considered superior to top-down approaches but are also more expensive to collect and analyze. In this article, we use value-of-information analysis to estimate the efficient mix of observations on each method in a proposed clinical trial. By assigning a prior bivariate distribution to the 2 data collection processes, the predicted posterior (i.e., preposterior) mean and variance of the superior process can be calculated from proposed samples using either process. This is then used to calculate the preposterior mean and variance of incremental net benefit and hence the expected net gain of sampling. We apply this method to a previously collected data set to estimate the value of conducting a further trial and identifying the optimal mix of observations on drug costs at 2 levels: by individual item (process A) and by drug class (process B). We find that substituting a number of observations on process A for process B leads to a modest £ 35,000 increase in expected net gain of sampling. Drivers of the results are the correlation between the 2 processes and their relative cost. This method has potential use following a pilot study to inform efficient data collection approaches for a subsequent full-scale trial. It provides a formal quantitative approach to inform trialists whether it is efficient to collect resource use data on all patients in a trial or on a subset of patients only or to collect limited data on most and detailed data on a subset. © The Author(s) 2016.

Timing of pregnancy, postpartum risk of virologic failure and loss to follow-up among HIV-positive women

PubMed Central

Onoya, Dorina; Sineke, Tembeka; Brennan, Alana T.; Long, Lawrence; Fox, Matthew P.

2017-01-01

Objectives: We assessed the association between the timing of pregnancy with the risk of postpartum virologic failure and loss from HIV care in South Africa. Design: This is a retrospective cohort study of 6306 HIV-positive women aged 15–49 at antiretroviral therapy (ART) initiation, initiated on ART between January 2004 and December 2013 in Johannesburg, South Africa. Methods: The incidence of virologic failure (two consecutive viral load measurements of >1000 copies/ml) and loss to follow-up (>3 months late for a visit) during 24 months postpartum were assessed using Cox proportional hazards modelling. Results: The rate of postpartum virologic failure was higher following an incident pregnancy on ART [adjusted hazard ratio 1.8, 95% confidence interval (CI): 1.1–2.7] than among women who initiated ART during pregnancy. This difference was sustained among women with CD4+ cell count less than 350 cells/μl at delivery (adjusted hazard ratio 1.8, 95% CI: 1.1–3.0). Predictors of postpartum virologic failure were being viremic, longer time on ART, being 25 or less years old and low CD4+ cell count and anaemia at delivery, as well as initiating ART on stavudine-containing or abacavir-containing regimen. There was no difference postpartum loss to follow-up rates between the incident pregnancies group (hazard ratio 0.9, 95% CI: 0.7–1.1) and those who initiated ART in pregnancy. Conclusion: The risk of virologic failure remains high among postpartum women, particularly those who conceive on ART. The results highlight the need to provide adequate support for HIV-positive women with fertility intention after ART initiation and to strengthen monitoring and retention efforts for postpartum women to sustain the benefits of ART. PMID:28463877

Relationship Between Time to Initiation of Antiretroviral Therapy and Treatment Outcomes: A Cohort Analysis of ART Eligible Adolescents in Zimbabwe

PubMed Central

Rehman, Andrea M.; Kranzer, Katharina; Nyathi, Mary; Van Griensven, Johan; Dixon, Mark; Ndebele, Wedu; Gunguwo, Hilary; Colebunders, Robert; Ndlovu, Mbongeni; Apollo, Tsitsi; Ferrand, Rashida A.

2017-01-01

Background: Age-specific retention challenges make antiretroviral therapy (ART) initiation in adolescents difficult, often requiring a lengthy preparation process. This needs to be balanced against the benefits of starting treatment quickly. The optimal time to initiation duration in adolescents is currently unknown. Objective: To assess the effect of time to ART initiation on mortality and loss to follow-up (LTFU) among treatment eligible adolescents. Methods: We conducted a retrospective cohort analysis among 1499 ART eligible adolescents aged ≥10 to <19 years registered in a public sector HIV program in Bulawayo, Zimbabwe, between 2004 and 2011. Hazard ratios (HR) for mortality and LTFU were calculated for different time to ART durations using multivariate Cox regression models. Results: Median follow-up duration was 1.6 years. Mortality HRs of patients who initiated at 0 to ≤7 days, >14 days to ≤1 month, >1 to ≤2 months, >2 months, and before initiation were 1.59, 1.19, 1.56, 1.08, and 0.94, respectively, compared with the reference group of >7 to ≤14 days. LTFU HRs were 1.02, 1.07, 0.85, 0.97, and 3.96, respectively. Among patients not on ART, 88% of deaths and 85% of LTFU occurred during the first 3 months after becoming ART eligible, but only 37% and 29% among adolescents on ART, respectively. Conclusions: Neither mortality or LTFU was associated with varying time to ART. The initiation process can be tailored to the adolescents' needs and individual life situations without risking to increase poor treatment outcomes. Early mortality was high despite rapid ART initiation, calling for earlier rather than faster initiation through HIV testing scale-up. PMID:28002183

Dissociable Effects of Aging and Mild Cognitive Impairment on Bottom-Up Audiovisual Integration.

PubMed

Festa, Elena K; Katz, Andrew P; Ott, Brian R; Tremont, Geoffrey; Heindel, William C

2017-01-01

Effective audiovisual sensory integration involves dynamic changes in functional connectivity between superior temporal sulcus and primary sensory areas. This study examined whether disrupted connectivity in early Alzheimer's disease (AD) produces impaired audiovisual integration under conditions requiring greater corticocortical interactions. Audiovisual speech integration was examined in healthy young adult controls (YC), healthy elderly controls (EC), and patients with amnestic mild cognitive impairment (MCI) using McGurk-type stimuli (providing either congruent or incongruent audiovisual speech information) under conditions differing in the strength of bottom-up support and the degree of top-down lexical asymmetry. All groups accurately identified auditory speech under congruent audiovisual conditions, and displayed high levels of visual bias under strong bottom-up incongruent conditions. Under weak bottom-up incongruent conditions, however, EC and amnestic MCI groups displayed opposite patterns of performance, with enhanced visual bias in the EC group and reduced visual bias in the MCI group relative to the YC group. Moreover, there was no overlap between the EC and MCI groups in individual visual bias scores reflecting the change in audiovisual integration from the strong to the weak stimulus conditions. Top-down lexicality influences on visual biasing were observed only in the MCI patients under weaker bottom-up conditions. Results support a deficit in bottom-up audiovisual integration in early AD attributable to disruptions in corticocortical connectivity. Given that this deficit is not simply an exacerbation of changes associated with healthy aging, tests of audiovisual speech integration may serve as sensitive and specific markers of the earliest cognitive change associated with AD.

Comparison between bottom-up and top-down approaches in the estimation of measurement uncertainty.

PubMed

Lee, Jun Hyung; Choi, Jee-Hye; Youn, Jae Saeng; Cha, Young Joo; Song, Woonheung; Park, Ae Ja

2015-06-01

Measurement uncertainty is a metrological concept to quantify the variability of measurement results. There are two approaches to estimate measurement uncertainty. In this study, we sought to provide practical and detailed examples of the two approaches and compare the bottom-up and top-down approaches to estimating measurement uncertainty. We estimated measurement uncertainty of the concentration of glucose according to CLSI EP29-A guideline. Two different approaches were used. First, we performed a bottom-up approach. We identified the sources of uncertainty and made an uncertainty budget and assessed the measurement functions. We determined the uncertainties of each element and combined them. Second, we performed a top-down approach using internal quality control (IQC) data for 6 months. Then, we estimated and corrected systematic bias using certified reference material of glucose (NIST SRM 965b). The expanded uncertainties at the low glucose concentration (5.57 mmol/L) by the bottom-up approach and top-down approaches were ±0.18 mmol/L and ±0.17 mmol/L, respectively (all k=2). Those at the high glucose concentration (12.77 mmol/L) by the bottom-up and top-down approaches were ±0.34 mmol/L and ±0.36 mmol/L, respectively (all k=2). We presented practical and detailed examples for estimating measurement uncertainty by the two approaches. The uncertainties by the bottom-up approach were quite similar to those by the top-down approach. Thus, we demonstrated that the two approaches were approximately equivalent and interchangeable and concluded that clinical laboratories could determine measurement uncertainty by the simpler top-down approach.

Reconciling Top-Down and Bottom-Up Estimates of Oil and Gas Methane Emissions in the Barnett Shale

NASA Astrophysics Data System (ADS)

Hamburg, S.

2015-12-01

Top-down approaches that use aircraft, tower, or satellite-based measurements of well-mixed air to quantify regional methane emissions have typically estimated higher emissions from the natural gas supply chain when compared to bottom-up inventories. A coordinated research campaign in October 2013 used simultaneous top-down and bottom-up approaches to quantify total and fossil methane emissions in the Barnett Shale region of Texas. Research teams have published individual results including aircraft mass-balance estimates of regional emissions and a bottom-up, 25-county region spatially-resolved inventory. This work synthesizes data from the campaign to directly compare top-down and bottom-up estimates. A new analytical approach uses statistical estimators to integrate facility emission rate distributions from unbiased and targeted high emission site datasets, which more rigorously incorporates the fat-tail of skewed distributions to estimate regional emissions of well pads, compressor stations, and processing plants. The updated spatially-resolved inventory was used to estimate total and fossil methane emissions from spatial domains that match seven individual aircraft mass balance flights. Source apportionment of top-down emissions between fossil and biogenic methane was corroborated with two independent analyses of methane and ethane ratios. Reconciling top-down and bottom-up estimates of fossil methane emissions leads to more accurate assessment of natural gas supply chain emission rates and the relative contribution of high emission sites. These results increase our confidence in our understanding of the climate impacts of natural gas relative to more carbon-intensive fossil fuels and the potential effectiveness of mitigation strategies.

The changing contribution of top-down and bottom-up limitation of mesopredators during 220 years of land use and climate change.

PubMed

Pasanen-Mortensen, Marianne; Elmhagen, Bodil; Lindén, Harto; Bergström, Roger; Wallgren, Märtha; van der Velde, Ype; Cousins, Sara A O

2017-05-01

Apex predators may buffer bottom-up driven ecosystem change, as top-down suppression may dampen herbivore and mesopredator responses to increased resource availability. However, theory suggests that for this buffering capacity to be realized, the equilibrium abundance of apex predators must increase. This raises the question: will apex predators maintain herbivore/mesopredator limitation, if bottom-up change relaxes resource constraints? Here, we explore changes in mesopredator (red fox Vulpes vulpes) abundance over 220 years in response to eradication and recovery of an apex predator (Eurasian lynx Lynx lynx), and changes in land use and climate which are linked to resource availability. A three-step approach was used. First, recent data from Finland and Sweden were modelled to estimate linear effects of lynx density, land use and winter temperature on fox density. Second, lynx density, land use and winter temperature was estimated in a 22 650 km 2 focal area in boreal and boreo-nemoral Sweden in the years 1830, 1920, 2010 and 2050. Third, the models and estimates were used to project historic and future fox densities in the focal area. Projected fox density was lowest in 1830 when lynx density was high, winters cold and the proportion of cropland low. Fox density peaked in 1920 due to lynx eradication, a mesopredator release boosted by favourable bottom-up changes - milder winters and cropland expansion. By 2010, lynx recolonization had reduced fox density, but it remained higher than in 1830, partly due to the bottom-up changes. Comparing 1830 to 2010, the contribution of top-down limitation decreased, while environment enrichment relaxed bottom-up limitation. Future scenarios indicated that by 2050, lynx density would have to increase by 79% to compensate for a projected climate-driven increase in fox density. We highlight that although top-down limitation in theory can buffer bottom-up change, this requires compensatory changes in apex predator abundance. Hence apex predator recolonization/recovery to historical levels would not be sufficient to compensate for widespread changes in climate and land use, which have relaxed the resource constraints for many herbivores and mesopredators. Variation in bottom-up conditions may also contribute to context dependence in apex predator effects. © 2017 The Authors. Journal of Animal Ecology © 2017 British Ecological Society.

Differentiating Co-Occurring Behavior Problems in Children with ADHD: Patterns of Emotional Reactivity and Executive Functioning

ERIC Educational Resources Information Center

Graziano, Paulo A.; McNamara, Joseph P.; Geffken, Gary R.; Reid, Adam M.

2013-01-01

Objective:This study examined whether "top-down" and "bottom-up" control processes can differentiate children with ADHD who exhibit co-occurring aggression and/or internalizing symptoms. Method: Participants included 74 children ("M" age = 10.7 years) with a "Diagnostic and Statistical…

Reversible storage of lithium in a rambutan-like tin-carbon electrode.

PubMed

Deng, Da; Lee, Jim Yang

2009-01-01

Fruity electrodes: A simple bottom-up self-assembly method was used to fabricate rambutan-like tin-carbon (Sn@C) nanoarchitecture (see scheme, green Sn) to improve the reversible storage of lithium in tin. The mechanism of the growth of the pear-like hairs is explored.

Removal of boron from ceramic industry wastewater by adsorption-flocculation mechanism using palm oil mill boiler (POMB) bottom ash and polymer.

PubMed

Chong, Mei Fong; Lee, Kah Peng; Chieng, Hui Jiun; Syazwani Binti Ramli, Ili Izyan

2009-07-01

Boron is extensively used in the ceramic industry for enhancing mechanical strength of the tiles. The discharge of boron containing wastewater to the environment causes severe pollution problems. Boron is also dangerous for human consumption and causes organisms' reproductive impediments if the safe intake level is exceeded. Current methods to remove boron include ion-exchange, membrane filtration, precipitation-coagulation, biological and chemical treatment. These methods are costly to remove boron from the wastewater and hence infeasible for industrial wastewater treatment. In the present research, adsorption-flocculation mechanism is proposed for boron removal from ceramic wastewater by using Palm Oil Mill Boiler (POMB) bottom ash and long chain polymer or flocculant. Ceramic wastewater is turbid and milky in color which contains 15 mg/L of boron and 2000 mg/L of suspended solids. The optimum operating conditions for boron adsorption on POMB bottom ash and flocculation using polymer were investigated in the present research. Adsorption isotherm of boron on bottom ash was also investigated to evaluate the adsorption capacity. Adsorption isotherm modeling was conducted based on Langmuir and Freundlich isotherms. The results show that coarse POMB bottom ash with particle size larger than 2 mm is a suitable adsorbent where boron is removed up to 80% under the optimum conditions (pH=8.0, dosage=40 g bottom ash/300 ml wastewater, residence time=1h). The results also show that KP 1200 B cationic polymer is effective in flocculating the suspended solids while AP 120 C anionic polymer is effective in flocculating the bottom ash. The combined cationic and anionic polymers are able to clarify the ceramic wastewater under the optimum conditions (dosage of KP 1200 B cationic polymer=100 mg/L, dosage of AP 120 C anionic polymer=50 mg/L, mixing speed=200 rpm). Under the optimum operating conditions, the boron and suspended solids concentration of the treated wastewater were reduced to 3 mg/L and 5 mg/L respectively, satisfying the discharge requirement by Malaysia Department of Environment (DOE). The modeling study shows that the adsorption isotherm of boron onto POMB bottom ash conformed to the Freundlich Isotherm. The proposed method is suitable for boron removal in ceramic wastewater especially in regions where POMB bottom ash is abundant.

Two-dimensional hexagonally oriented CdCl2.H2O nanorod assembly: formation and replication.

PubMed

Deng, Zhaoxiang; Mao, Chengde

2004-09-14

This paper reports a simple bottom-up method that can controllably fabricate 2D hexagonally oriented and randomly distributed CdCl(2).H(2)O nanorods on mica surfaces. The as-formed nanorod assemblies have been successfully replicated into various matrixes, including gold, poly(dimethylsiloxane), and polyurethane. Thus, this method is compatible with soft-lithography towards further applications.

HIV models for treatment interruption: Adaptation and comparison

NASA Astrophysics Data System (ADS)

Hillmann, Andreas; Crane, Martin; Ruskin, Heather J.

2017-10-01

In recent years, Antiretroviral Therapy (ART) has become commonplace for treating HIV infections, although a cure remains elusive, given reservoirs of replicating latently-infected cells, which are resistant to normal treatment regimes. Treatment interruptions, whether ad hoc or structured, are known to cause a rapid increase in viral production to detectable levels, but numerous clinical trials remain inconclusive on the dangers inherent in this resurgence. In consequence, interest in examining interruption strategies has recently been rekindled. This overview considers modelling approaches, which have been used to explore the issue of treatment interruption. We highlight their purpose and the formalisms employed and examine ways in which clinical data have been used. Implementation of selected models is demonstrated, illustrative examples provided and model performance compared for these cases. Possible extensions to bottom-up modelling techniques for treatment interruptions are briefly discussed.

Aesthetic episodes, domains, and the mind. Comment on: "Move me, astonish me... delight my eyes and brain: The Vienna Integrated Model of top-down and bottom-up processes in Art Perception (VIMAP) and corresponding affective, evaluative, and neurophysiological correlates" by Matthew Pelowski et al.

NASA Astrophysics Data System (ADS)

Jacobsen, Thomas

2017-07-01

Aesthetic episodes, as all behavior, are situated. They take place as an interaction of person and situation variables [1]. There are different artistic and aesthetic domains that afford, in part, mutual mental processes, but also fundamentally different, e.g., modality-specific ones [2]. For the infinite number of possible aesthetic episodes a plethora of component processes can be selectively combined and dynamically configured. Following psychophysics' pragmatic dualism of mind and body, this results in dynamically configured (neuro-) biological networks subserving these mental processes [1]. These are, of course, also subject to evolutionary, biological, historical, cultural, and social change [1,3].

Bottom-up meets top-down: tailored raspberry-like Fe 3 O 4 –Pt nanocrystal superlattices

DOE PAGES

Qiu, Fen; Vervuurt, René H. J.; Verheijen, Marcel A.; ...

2018-01-01

Bottom up colloidal synthesis is combined with top down atomic layer deposition to achieve raspberry-like Pt-decorated Fe 3 O 4 nanoparticle superlattices with good metal–oxide–metal contact for photoelectrocatalysis.

Bottom-up meets top-down: tailored raspberry-like Fe 3 O 4 –Pt nanocrystal superlattices

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

Qiu, Fen; Vervuurt, René H. J.; Verheijen, Marcel A.

Bottom up colloidal synthesis is combined with top down atomic layer deposition to achieve raspberry-like Pt-decorated Fe 3 O 4 nanoparticle superlattices with good metal–oxide–metal contact for photoelectrocatalysis.

Biologically inspired multi-layered synthetic skin for tactile feedback in prosthetic limbs.

PubMed

Osborn, Luke; Nguyen, Harrison; Betthauser, Joseph; Kaliki, Rahul; Thakor, Nitish

2016-08-01

The human body offers a template for many state-of-the-art prosthetic devices and sensors. In this work, we present a novel, sensorized synthetic skin that mimics the natural multi-layered nature of mechanoreceptors found in healthy glabrous skin to provide tactile information. The multi-layered sensor is made up of flexible piezoresistive textiles that act as force sensitive resistors (FSRs) to convey tactile information, which are embedded within a silicone rubber to resemble the compliant nature of human skin. The top layer of the synthetic skin is capable of detecting small loads less than 5 N whereas the bottom sensing layer responds reliably to loads over 7 N. Finite element analysis (FEA) of a simplified human fingertip and the synthetic skin was performed. Results suggest similarities in behavior during loading. A natural tactile event is simulated by loading the synthetic skin on a prosthetic limb. Results show the sensors' ability to detect applied loads as well as the ability to simulate neural spiking activity based on the derivative and temporal differences of the sensor response. During the tactile loading, the top sensing layer responded 0.24 s faster than the bottom sensing layer. A synthetic biologically-inspired skin such as this will be useful for enhancing the functionality of prosthetic limbs through tactile feedback.

Thermodynamic properties for applications in chemical industry via classical force fields.

PubMed

Guevara-Carrion, Gabriela; Hasse, Hans; Vrabec, Jadran

2012-01-01

Thermodynamic properties of fluids are of key importance for the chemical industry. Presently, the fluid property models used in process design and optimization are mostly equations of state or G (E) models, which are parameterized using experimental data. Molecular modeling and simulation based on classical force fields is a promising alternative route, which in many cases reasonably complements the well established methods. This chapter gives an introduction to the state-of-the-art in this field regarding molecular models, simulation methods, and tools. Attention is given to the way modeling and simulation on the scale of molecular force fields interact with other scales, which is mainly by parameter inheritance. Parameters for molecular force fields are determined both bottom-up from quantum chemistry and top-down from experimental data. Commonly used functional forms for describing the intra- and intermolecular interactions are presented. Several approaches for ab initio to empirical force field parameterization are discussed. Some transferable force field families, which are frequently used in chemical engineering applications, are described. Furthermore, some examples of force fields that were parameterized for specific molecules are given. Molecular dynamics and Monte Carlo methods for the calculation of transport properties and vapor-liquid equilibria are introduced. Two case studies are presented. First, using liquid ammonia as an example, the capabilities of semi-empirical force fields, parameterized on the basis of quantum chemical information and experimental data, are discussed with respect to thermodynamic properties that are relevant for the chemical industry. Second, the ability of molecular simulation methods to describe accurately vapor-liquid equilibrium properties of binary mixtures containing CO(2) is shown.

SU-C-204-06: Surface Imaging for the Set-Up of Proton Post-Mastectomy Chestwall Irradiation: Gated Images Vs Non Gated Images

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

Batin, E; Depauw, N; MacDonald, S

Purpose: Historically, the set-up for proton post-mastectomy chestwall irradiation at our institution started with positioning the patient using tattoos and lasers. One or more rounds of orthogonal X-rays at gantry 0° and beamline X-ray at treatment gantry angle were then taken to finalize the set-up position. As chestwall targets are shallow and superficial, surface imaging is a promising tool for set-up and needs to be investigated Methods: The orthogonal imaging was entirely replaced by AlignRT™ (ART) images. The beamline X-Ray image is kept as a confirmation, based primarily on three opaque markers placed on skin surface instead of bony anatomy.more » In the first phase of the process, ART gated images were used to set-up the patient and the same specific point of the breathing curve was used every day. The moves (translations and rotations) computed for each point of the breathing curve during the first five fractions were analyzed for ten patients. During a second phase of the study, ART gated images were replaced by ART non-gated images combined with real-time monitoring. In both cases, ART images were acquired just before treatment to access the patient position compare to the non-gated CT. Results: The average difference between the maximum move and the minimum move depending on the chosen breathing curve point was less than 1.7 mm for all translations and less than 0.7° for all rotations. The average position discrepancy over the course of treatment obtained by ART non gated images combined to real-time monitoring taken before treatment to the planning CT were smaller than the average position discrepancy obtained using ART gated images. The X-Ray validation images show similar results with both ART imaging process. Conclusion: The use of ART non gated images combined with real time imaging allows positioning post-mastectomy chestwall patients in less than 3 mm / 1°.« less

Impact of drug classes and treatment availability on the rate of antiretroviral treatment change in the TREAT Asia HIV Observational Database (TAHOD)

PubMed Central

Srasuebkul, Preeyaporn; Calmy, Alexandra; Zhou, Jialun; Kumarasamy, Nagalingeswaran; Law, Matthew; Lim, Poh Lian

2007-01-01

Background It is critical to understand the pattern of antiretroviral treatment (ART) prescription in different regions of the world as ART procurement needs to be anticipated. We aimed at exploring rates and predictors of ART combination changes in clinical practice in Treat Asia HIV Observational Database (TAHOD). Methods Rates of ART changes were examined in patients who started first line triple or more ART combination in TAHOD, and had at least one follow-up visit. Rates of ART changes were summarised per follow-up year, and factors associated with changes assessed using random-effect Poisson regression. The Kaplan-Meier method was used to determine durations of patients in their first, second and third regimen. Results A total of 1846 patients initiated an ART combination with at least three drugs. Median follow up time for the first treatment was 3.2 years. The overall rate of ART change was 29 per 100-person-year. In univariate analyses, rate of treatment change was significantly associated with exposure category, the country income category, the drug class combination, calendar year and the number of combinations. In multivariate analysis, compared to d4T/3TC/NVP, starting ART with another NNRTI-containing regimen, with PI only or with a triple NRTI regimen was associated with a higher risk of combination change (relative risk (RR) 1.6 (95% CI 1.64 – 1.96), p < 0.001, RR 3.39 (2.76 – 4.16) p < 0.001, RR 6.37 (4.51 – 9.00), p < 0.001). Being on a second or a third combination regimen was also associated with a decreased rate of ART change, compared with first ART combination (RR 0.82 (0.68 – 0.99), p = 0.035, RR 0.77 (0.61 – 0.97), p = 0.024). Sites with fewer than 12 drugs used had an increased rate of treatment changes (1.31 (1.13 – 1.51), p < 0.001). Injecting drug users, and other/unknown exposure was found to increase rate of treatment change (1.24 (1.00 – 1.54), p = 0.055). Percentages of patients who stopped treatment due to adverse events were 31, 27 and 32 in 1st, 2nd and 3rd treatment combinations, respectively. Conclusion Our study suggests that drug availability impacts on ART prescription patterns. Our data, reflecting real clinic use in Asia, suggest that around half of all patients require second combination ART by 3 years after treatment initiation. PMID:17868478

Sustainability, Student Affairs, and Students

ERIC Educational Resources Information Center

Kerr, Kathleen G.; Hart-Steffes, Jeanne S.

2012-01-01

Colleges and universities are developing both the next generation of leaders as well as state-of-the-art technology that allow climate reduction aspirations and triple bottom-line outcomes to become realities. Divisions of student affairs play a crucial role in the sustainability movement in colleges and universities. The technology-savvy,…

What are the fluxes of greenhouse gases from the greater Los Angeles area as inferred from top-down remote sensing studies?

NASA Astrophysics Data System (ADS)

Hedelius, J.; Wennberg, P. O.; Wunch, D.; Roehl, C. M.; Podolske, J. R.; Hillyard, P.; Iraci, L. T.

2017-12-01

Greenhouse gas (GHG) emissions from California's South Coast Air Basin (SoCAB) have been studied extensively using a variety of tower, aircraft, remote sensing, emission inventory, and modeling studies. It is impractical to survey GHG fluxes from all urban areas and hot-spots to the extent the SoCAB has been studied, but it can serve as a test location for scaling methods globally. We use a combination of remote sensing measurements from ground (Total Carbon Column Observing Network, TCCON) and space-based (Observing Carbon Observatory-2, OCO-2) sensors in an inversion to obtain the carbon dioxide flux from the SoCAB. We also perform a variety of sensitivity tests to see how the inversion performs using different model parameterizations. Fluxes do not significantly depend on the mixed layer depth, but are sensitive to the model surface layers (<5 m). Carbon dioxide fluxes are larger than those from bottom-up inventories by about 20%, and along with CO has a significant weekend:weekday effect. Methane fluxes have little weekend changes. Results also include flux estimates from sub-regions of the SoCAB. Larger top-down than bottom-up fluxes highlight the need for additional work on both approaches. Higher top-down fluxes could arise from sampling bias, model bias, or may show bottom-up values underestimate sources. Lessons learned here may help in scaling up inversions to hundreds of urban systems using space-based observations.

An adaptive radiotherapy planning strategy for bladder cancer using deformation vector fields.

PubMed

Vestergaard, Anne; Kallehauge, Jesper Folsted; Petersen, Jørgen Breede Baltzer; Høyer, Morten; Søndergaard, Jimmi; Muren, Ludvig Paul

2014-09-01

Adaptive radiotherapy (ART) has considerable potential in treatment of bladder cancer due to large inter-fractional changes in shape and size of the target. The aim of this study was to compare our clinically applied method for plan library creation that involves manual bladder delineations (Clin-ART) with a method using the deformation vector fields (DVFs) resulting from intensity-based deformable image registrations (DVF-based ART). The study included thirteen patients with urinary bladder cancer who had daily cone beam CTs (CBCTs) acquired for set-up. In both ART strategies investigated, three plan selection volumes were generated using the CBCTs from the first four fractions; in Clin-ART boolean combinations of delineated bladders were used, while the DVF-based strategy applied combinations of the mean and standard deviation of patient-specific DVFs. The volume ratios (VRs) of the course-averaged PTV for the two ART strategies relative the non-adaptive PTV were calculated. Both Clin-ART and DVF-based ART considerably reduced the course-averaged PTV, compared to non-adaptive RT. The VR for DVF-based ART was lower than for Clin-ART (0.65 vs. 0.73; p<0.01). DVF-based ART for bladder irradiation has a considerable normal tissue sparing potential surpassing our already highly conformal clinically applied ART strategy. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Modelization of highly nonlinear waves in coastal regions

NASA Astrophysics Data System (ADS)

Gouin, Maïté; Ducrozet, Guillaume; Ferrant, Pierre

2015-04-01

The proposed work deals with the development of a highly non-linear model for water wave propagation in coastal regions. The accurate modelization of surface gravity waves is of major interest in ocean engineering, especially in the field of marine renewable energy. These marine structures are intended to be settled in coastal regions where the effect of variable bathymetry may be significant on local wave conditions. This study presents a numerical model for the wave propagation with complex bathymetry. It is based on High-Order Spectral (HOS) method, initially limited to the propagation of non-linear wave fields over flat bottom. Such a model has been developed and validated at the LHEEA Lab. (Ecole Centrale Nantes) over the past few years and the current developments will enlarge its application range. This new numerical model will keep the interesting numerical properties of the original pseudo-spectral approach (convergence, efficiency with the use of FFTs, …) and enable the possibility to propagate highly non-linear wave fields over long time and large distance. Different validations will be provided in addition to the presentation of the method. At first, Bragg reflection will be studied with the proposed approach. If the Bragg condition is satisfied, the reflected wave generated by a sinusoidal bottom patch should be amplified as a result of resonant quadratic interactions between incident wave and bottom. Comparisons will be provided with experiments and reference solutions. Then, the method will be used to consider the transformation of a non-linear monochromatic wave as it propagates up and over a submerged bar. As the waves travel up the front slope of the bar, it steepens and high harmonics are generated due to non-linear interactions. Comparisons with experimental data will be provided. The different test cases will assess the accuracy and efficiency of the method proposed.

The impact of a visual arts program on quality of life, communication, and well-being of people living with dementia: a mixed-methods longitudinal investigation.

PubMed

Windle, Gill; Joling, Karlijn J; Howson-Griffiths, Teri; Woods, Bob; Jones, Catrin Hedd; van de Ven, Peter M; Newman, Andrew; Parkinson, Clive

2018-03-01

ABSTRACTBackground:Research reviews highlight methodological limitations and gaps in the evidence base for the arts in dementia care. In response, we developed a 12-week visual art program and evaluated the impact on people living with dementia through a mixed-methods longitudinal investigation. One hundred and twenty-five people living with mild to severe dementia were recruited across three research settings in England and Wales (residential care homes, a county hospital, and community venues). Quantitative and qualitative data on quality of life (QoL), communication and perceptions of the program were obtained through interviews and self-reports with participants and their carers. Eight domains of well-being were measured using a standardized observation tool, and data compared to an alternative activity with no art. Across all sites, scores for the well-being domains of interest, attention, pleasure, self-esteem, negative affect, and sadness were significantly better in the art program than the alternative condition. Proxy-reported QoL significantly improved between baseline and 3-month follow-up, but no improvements in QoL were reported by the participants with dementia. This was contrasted by their qualitative accounts, which described a stimulating experience important for social connectedness, well-being, and inner-strength. Communication deteriorated between baseline and follow-up in the hospital setting, but improved in the residential care setting. The findings highlight the potential for creative aging within dementia care, the benefits of art activities and the influence of the environment. We encourage dementia care providers and arts and cultural services to work toward embedding art activities within routine care provision.

Looking behaviour and preference for artworks: the role of emotional valence and location.

PubMed

Kreplin, Ute; Thoma, Volker; Rodway, Paul

2014-10-01

The position of an item influences its evaluation, with research consistently finding that items occupying central locations are preferred and have a higher subjective value. The current study investigated whether this centre-stage effect (CSE) is a result of bottom-up gaze allocation to the central item, and whether it is affected by item valence. Participants (n=50) were presented with three images of artistic paintings in a row and asked to choose the image they preferred. Eye movements were recorded for a subset of participants (n=22). On each trial the three artworks were either similar but different, or were identical and with positive valence, or were identical and with negative valence. The results showed a centre-stage effect, with artworks in the centre of the row preferred, but only when they were identical and of positive valence. Significantly greater gaze allocation to the central and left artwork was not mirrored by equivalent increases in preference choices. Regression analyses showed that when the artworks were positive and identical the participants' last fixation predicted preference for the central art-work, whereas the fixation duration predicted preference if the images were different. Overall the result showed that item valence, rather than level of gaze allocation, influences the CSE, which is incompatible with the bottom-up gaze explanation. We propose that the centre stage heuristic, which specifies that the best items are in the middle, is able to explain these findings and the centre-stage effect. Copyright © 2014 Elsevier B.V. All rights reserved.

Method to implement the CCD timing generator based on FPGA

NASA Astrophysics Data System (ADS)

Li, Binhua; Song, Qian; He, Chun; Jin, Jianhui; He, Lin

2010-07-01

With the advance of the PFPA technology, the design methodology of digital systems is changing. In recent years we develop a method to implement the CCD timing generator based on FPGA and VHDL. This paper presents the principles and implementation skills of the method. Taking a developed camera as an example, we introduce the structure, input and output clocks/signals of a timing generator implemented in the camera. The generator is composed of a top module and a bottom module. The bottom one is made up of 4 sub-modules which correspond to 4 different operation modes. The modules are implemented by 5 VHDL programs. Frame charts of the architecture of these programs are shown in the paper. We also describe implementation steps of the timing generator in Quartus II, and the interconnections between the generator and a Nios soft core processor which is the controller of this generator. Some test results are presented in the end.

Relative importance of top-down and bottom-up forces in food webs of Sarracenia pitcher communities at a northern and a southern site.

PubMed

Hoekman, David

2011-04-01

The relative importance of resources (bottom-up forces) and natural enemies (top-down forces) for regulating food web dynamics has been debated, and both forces have been found to be critical for determining food web structure. How the relative importance of top-down and bottom-up forces varies between sites with different abiotic conditions is not well understood. Using the pitcher plant inquiline community as a model system, I examine how the relative importance of top-down and bottom-up effects differs between two disparate sites. Resources (ant carcasses) and top predators (mosquito larvae) were manipulated in two identical 4 × 4 factorial press experiments, conducted at two geographically distant sites (Michigan and Florida) within the range of the purple pitcher plant, Sarracenia purpurea, and the aquatic community that resides in its leaves. Overall, top predators reduced the density of prey populations while additional resources bolstered them, and the relative importance of top-down and bottom-up forces varied between sites and for different trophic levels. Specifically, top-down effects on protozoa were stronger in Florida than in Michigan, while the opposite pattern was found for rotifers. These findings experimentally demonstrate that the strength of predator-prey interactions, even those involving the same species, vary across space. While only two sites are compared in this study, I hypothesize that site differences in temperature, which influences metabolic rate, may be responsible for variation in consumer-resource interactions. These findings warrant further investigation into the specific factors that modify the relative importance of top-down and bottom-up effects.

Stochastic error model corrections to improve the performance of bottom-up precipitation products for hydrologic applications

NASA Astrophysics Data System (ADS)

Maggioni, V.; Massari, C.; Ciabatta, L.; Brocca, L.

2016-12-01

Accurate quantitative precipitation estimation is of great importance for water resources management, agricultural planning, and forecasting and monitoring of natural hazards such as flash floods and landslides. In situ observations are limited around the Earth, especially in remote areas (e.g., complex terrain, dense vegetation), but currently available satellite precipitation products are able to provide global precipitation estimates with an accuracy that depends upon many factors (e.g., type of storms, temporal sampling, season, etc.). The recent SM2RAIN approach proposes to estimate rainfall by using satellite soil moisture observations. As opposed to traditional satellite precipitation methods, which sense cloud properties to retrieve instantaneous estimates, this new bottom-up approach makes use of two consecutive soil moisture measurements for obtaining an estimate of the fallen precipitation within the interval between two satellite overpasses. As a result, the nature of the measurement is different and complementary to the one of classical precipitation products and could provide a different valid perspective to substitute or improve current rainfall estimates. However, uncertainties in the SM2RAIN product are still not well known and could represent a limitation in utilizing this dataset for hydrological applications. Therefore, quantifying the uncertainty associated with SM2RAIN is necessary for enabling its use. The study is conducted over the Italian territory for a 5-yr period (2010-2014). A number of satellite precipitation error properties, typically used in error modeling, are investigated and include probability of detection, false alarm rates, missed events, spatial correlation of the error, and hit biases. After this preliminary uncertainty analysis, the potential of applying the stochastic rainfall error model SREM2D to correct SM2RAIN and to improve its performance in hydrologic applications is investigated. The use of SREM2D for characterizing the error in precipitation by SM2RAIN would be highly useful for the merging and the integration steps in its algorithm, i.e., the merging of multiple soil moisture derived products (e.g., SMAP, SMOS, ASCAT) and the integration of soil moisture derived and state of the art satellite precipitation products (e.g., GPM IMERG).

A three-dimensional numerical simulation of cell behavior in a flow chamber based on fluid-solid interaction.

PubMed

Bai, Long; Cui, Yuhong; Zhang, Yixia; Zhao, Na

2014-01-01

The mechanical behavior of blood cells in the vessels has a close relationship with the physical characteristics of the blood and the cells. In this paper, a numerical simulation method was proposed to understand a single-blood cell's behavior in the vessels based on fluid-solid interaction method, which was conducted under adaptive time step and fixed time step, respectively. The main programme was C++ codes, which called FLUENT and ANSYS software, and UDF and APDL acted as a messenger to connect FLUENT and ANSYS for exchanging data. The computing results show: (1) the blood cell moved towards the bottom of the flow chamber in the beginning due to the influence of gravity, then it began to jump up when reached a certain height rather than touching the bottom. It could move downwards again after jump up, the blood cell could keep this way of moving like dancing continuously in the vessels; (2) the blood cell was rolling and deforming all the time; the rotation had oscillatory changes and the deformation became conspicuously when the blood cell was dancing. This new simulation method and results can be widely used in the researches of cytology, blood, cells, etc.

Modifications to ART service delivery models by health facilities in Uganda in promotion of intervention sustainability: a mixed methods study.

PubMed

Zakumumpa, Henry; Bennett, Sara; Ssengooba, Freddie

2017-04-04

In November 2015, WHO released new treatment guidelines recommending that all diagnosed as HIV positive be enrolled on antiretroviral therapy (ART). Sustaining and expanding ART scale-up programs in resource-limited settings will require adaptations and modifications to traditional ART delivery models to meet the rapid increase in demand. We identify modifications to ART service delivery models by health facilities in Uganda to sustain ART interventions over a 10-year period (2004-2014). A mixed methods approach involving two study phases was adopted. In the first phase, a survey of a nationally representative sample of health facilities (n = 195) in Uganda which were accredited to provide ART between 2004 and 2009 was conducted. The second phase involved semi-structured interviews (n = 18) with ART clinic managers of 6 of the 195 health facilities purposively selected from the first study phase. We adopted a thematic framework consisting of four categories of modifications (format, setting, personnel, and population). The majority of health facilities 185 (95%) reported making modifications to ART interventions between 2004 and 2014. Of the 195 health facilities, 157 (81%) rated the modifications made to ART as "major." Modifications to ART were reported under all the four themes. The quantitative and qualitative findings are integrated and presented under four themes. Format: Reducing the frequency of clinic appointments and pharmacy-only refill programs was identified as important strategies for decongesting ART clinics. Home-based care programs were introduced to reduce provider ART delivery costs. Personnel: Task shifting to non-physician cadre was reported in 181 (93%) of the health facilities. Visits to the ART clinic were rationalized in favor of the sub-population deemed to have more clinical need. Two health facilities focused on patients living nearer the health facilities to align with targets set by external donors. Over the study period, health facilities made several modifications ART interventions to improve fit with their resource-constrained settings thereby promoting long-term sustainability. Further research evaluating the effect of these modifications on patient outcomes and ART delivery costs is recommended. Our findings have implications for the sustainability of ART scale-up programs in Uganda and other resource-limited settings.

Monitoring the scale-up of antiretroviral therapy programmes: methods to estimate coverage.

PubMed Central

Boerma, J. Ties; Stanecki, Karen A.; Newell, Marie-Louise; Luo, Chewe; Beusenberg, Michel; Garnett, Geoff P.; Little, Kirsty; Calleja, Jesus Garcia; Crowley, Siobhan; Kim, Jim Yong; Zaniewski, Elizabeth; Walker, Neff; Stover, John; Ghys, Peter D.

2006-01-01

This paper reviews the data sources and methods used to estimate the number of people on, and coverage of, antiretroviral therapy (ART) programmes in low- and middle-income countries and to monitor the progress towards the "3 by 5" target set by WHO and UNAIDS. We include a review of the data sources used to estimate the coverage of ART programmes as well as the efforts made to avoid double counting and over-reporting. The methods used to estimate the number of people in need of ART are described and expanded with estimates of treatment needs for children, both for ART and for cotrimoxazole prophylaxis. An estimated 6.5 million people were in need of treatment in low- and middle-income countries by the end of 2004, including 660,000 children under age 15 years. The mid-2005 estimate of 970,000 people receiving ART in low- and middle-income countries (with an uncertainty range 840,000-1,100,000) corresponds to a coverage of 15% of people in need of treatment. PMID:16501733

Will the "Real" Proficiency Standard Please Stand Up?

ERIC Educational Resources Information Center

Baron, Joan Boykoff; And Others

Connecticut's experience with four different standard-setting methods regarding multiple choice proficiency tests is described. The methods include Angoff, Nedelsky, Borderline Group, and Contrasting Groups Methods. All Connecticut ninth graders were administered proficiency tests in reading, language arts, and mathematics. As soon as final test…

Bottom-up GGM algorithm for constructing multiple layered hierarchical gene regulatory networks

USDA-ARS?s Scientific Manuscript database

Multilayered hierarchical gene regulatory networks (ML-hGRNs) are very important for understanding genetics regulation of biological pathways. However, there are currently no computational algorithms available for directly building ML-hGRNs that regulate biological pathways. A bottom-up graphic Gaus...

Voluntary task switching under load: contribution of top-down and bottom-up factors in goal-directed behavior.

PubMed

Demanet, Jelle; Verbruggen, Frederick; Liefooghe, Baptist; Vandierendonck, André

2010-06-01

The present study investigated the relative contribution of bottom-up and top-down control to task selection in the voluntary task-switching (VTS) procedure. In order to manipulate the efficiency of top-down control, a concurrent working memory load was imposed during VTS. In three experiments, bottom-up factors, such as stimulus repetitions, repetition of irrelevant information, and stimulus-task associations, were introduced in order to investigate their influence on task selection. We observed that the tendency to repeat tasks was stronger under load, suggesting that top-down control counteracts the automatic tendency to repeat tasks. The results also indicated that task selection can be guided by several elements in the environment, but that only the influence of stimulus repetitions depends on the efficiency of top-down control. The theoretical implications of these findings are discussed within the interplay between top-down and bottom-up control that underlies the voluntary selection of tasks.

Self-assembled nanostructured resistive switching memory devices fabricated by templated bottom-up growth

PubMed Central

Song, Ji-Min; Lee, Jang-Sik

2016-01-01

Metal-oxide-based resistive switching memory device has been studied intensively due to its potential to satisfy the requirements of next-generation memory devices. Active research has been done on the materials and device structures of resistive switching memory devices that meet the requirements of high density, fast switching speed, and reliable data storage. In this study, resistive switching memory devices were fabricated with nano-template-assisted bottom up growth. The electrochemical deposition was adopted to achieve the bottom-up growth of nickel nanodot electrodes. Nickel oxide layer was formed by oxygen plasma treatment of nickel nanodots at low temperature. The structures of fabricated nanoscale memory devices were analyzed with scanning electron microscope and atomic force microscope (AFM). The electrical characteristics of the devices were directly measured using conductive AFM. This work demonstrates the fabrication of resistive switching memory devices using self-assembled nanoscale masks and nanomateirals growth from bottom-up electrochemical deposition. PMID:26739122

Bottom-Up Tri-gate Transistors and Submicrosecond Photodetectors from Guided CdS Nanowalls.

PubMed

Xu, Jinyou; Oksenberg, Eitan; Popovitz-Biro, Ronit; Rechav, Katya; Joselevich, Ernesto

2017-11-08

Tri-gate transistors offer better performance than planar transistors by exerting additional gate control over a channel from two lateral sides of semiconductor nanowalls (or "fins"). Here we report the bottom-up assembly of aligned CdS nanowalls by a simultaneous combination of horizontal catalytic vapor-liquid-solid growth and vertical facet-selective noncatalytic vapor-solid growth and their parallel integration into tri-gate transistors and photodetectors at wafer scale (cm 2 ) without postgrowth transfer or alignment steps. These tri-gate transistors act as enhancement-mode transistors with an on/off current ratio on the order of 10 8 , 4 orders of magnitude higher than the best results ever reported for planar enhancement-mode CdS transistors. The response time of the photodetector is reduced to the submicrosecond level, 1 order of magnitude shorter than the best results ever reported for photodetectors made of bottom-up semiconductor nanostructures. Guided semiconductor nanowalls open new opportunities for high-performance 3D nanodevices assembled from the bottom up.

Scale-up of a decentralized HIV treatment programme in rural KwaZulu-Natal, South Africa: does rapid expansion affect patient outcomes?

PubMed Central

Mutevedzi, Portia C; Lessells, Richard J; Heller, Tom; Bärnighausen, Till; Cooke, Graham S; Newell, Marie-Louise

2010-01-01

Abstract Objective To describe the scale-up of a decentralized HIV treatment programme delivered through the primary health care system in rural KwaZulu-Natal, South Africa, and to assess trends in baseline characteristics and outcomes in the study population. Methods The programme started delivery of antiretroviral therapy (ART) in October 2004. Information on all patients initiated on ART was captured in the programme database and follow-up status was updated monthly. All adult patients (≥ 16 years) who initiated ART between October 2004 and September 2008 were included and stratified into 6-month groups. Clinical and sociodemographic characteristics were compared between the groups. Retention in care, mortality, loss to follow-up and virological outcomes were assessed at 12 months post-ART initiation. Findings A total of 5719 adults initiated on ART were included (67.9% female). Median baseline CD4+ lymphocyte count was 116 cells/µl (interquartile range, IQR: 53–173). There was an increase in the proportion of women who initiated ART while pregnant but no change in other baseline characteristics over time. Overall retention in care at 12 months was 84.0% (95% confidence interval, CI: 82.6–85.3); 10.9% died (95% CI: 9.8–12.0); 3.7% were lost to follow-up (95% CI: 3.0–4.4). Mortality was highest in the first 3 months after ART initiation: 30.1 deaths per 100 person–years (95% CI: 26.3–34.5). At 12 months 23.0% had a detectable viral load (> 25 copies/ml) (95% CI: 19.5–25.5). Conclusion Outcomes were not affected by rapid expansion of this decentralized HIV treatment programme. The relatively high rates of detectable viral load highlight the need for further efforts to improve the quality of services. PMID:20680124

Outcomes of antiretroviral therapy in children in Asia and Africa: a comparative analysis of the IeDEA pediatric multiregional collaboration

PubMed Central

Leroy, Valeriane; Malateste, Karen; Rabie, Helena; Lumbiganon, Pagakrong; Ayaya, Samuel; Dicko, Fatoumata; Davies, Mary-Ann; Kariminia, Azar; Wools-Kaloustian, Kara; Aka, Edmond; Phiri, Samuel; Aurpibul, Linda; Yiannoutsos, Constantin; Signaté-Sy, Haby; Mofenson, Lynne; Dabis, François

2013-01-01

Background We investigated 18-month incidence and determinants of death and loss-to-follow-up of children after antiretroviral therapy (ART) initiation in a multiregional collaboration in lower-income countries. Methods HIV-infected children (positive PCR <18 months or positive serology ≥18 months) from IeDEA cohorts, <16 years, initiating ART were eligible. A competing risk regression model was used to analyze the independent risk of two failure types: death and loss-to-follow-up (>6 months). Findings Data on 13611 children, from Asia (N=1454), East-Africa (N=3114), Southern-Africa (N=6212) and West-Africa (N=2881) contributed 20,417 person-years of follow-up. At 18 months, the adjusted risk of death was 4.3% in East-Africa, 5.4% in Asia, 5.7% in Southern-Africa and 7.4% in West-Africa (P=0.01). Age<24 months, WHO stage 4, CD4<10%, attending a private sector clinic, larger cohort size and living in West-Africa were independently associated with poorer survival. The adjusted risk of loss-to-follow-up was 4.1% in Asia, 9.0% in Southern-Africa, 14.0% in East-Africa, and 21.8% in West-Africa (P <0.01). Age<12 months, non NNRTI-based ART regimen, WHO stage 4 at ART start, ART initiation after 2005, attending a public sector or a non-urban clinic, having to pay for laboratory tests or antiretroviral drugs, larger cohort size, and living in East or West-Africa were significantly associated with higher loss-to-follow-up. Conclusion Findings differed substantially across regions but raise overall concerns about delayed ART start, low access to free HIV-services for children, and increased workload on program retention in lower-income countries. Universal free access to ART services and innovative approaches are urgently needed to improve pediatric outcomes at program level. PMID:23187940

Implementation and Operational Research: Early Tracing of Children Lost to Follow-Up From Antiretroviral Treatment: True Outcomes and Future Risks

PubMed Central

Ardura-Garcia, Cristina; Feldacker, Caryl; Tweya, Hannock; Chaweza, Thom; Kalulu, Mike; Phiri, Sam; Wang, Duolao

2015-01-01

Background: Loss to follow-up (LTFU) challenges the success of antiretroviral therapy (ART) scale-up among pediatric patients. Little is known about children who drop out of care. We aim to analyze risk factors for LTFU among children on ART, find their true outcomes through tracing, and investigate their final outcomes after resuming ART. Methods: This is a descriptive, retrospective, cohort study of children on ART between April 2006 and December 2010 in 2 clinics in urban Malawi. Routine data from an electronic data system were used and matched with information obtained through routine tracing procedures. Results: Of 985 children (1999 child-years) on ART, 251 were LTFU: 12.6/100 child-years. At ART initiation, wasting [adjusted hazard ratio (AHR) 1.58 and 95% confidence interval (CI): 1.02 to 2.44] was independently associated with higher risk of LTFU. Of 201 LTFU children traced, 79% were found: 11% died, 25% stopped, 26% transferred-out, and 37% were still on ART. Median time between last visit and first tracing was 84 days (interquartile range: 64–101 days). Tracing reduced risk of LTFU by 38% (AHR 0.62 and 95% CI: 0.42 to 0.91) and decreased LTFU from 23.2% to 8.5%. Additional outcomes of stop, death, and transfer-out increased 4.4-fold, 1.8-fold, and 1.3-fold, respectively. Traced children with gaps in ART intake who resumed ART had higher risk of stopping (AHR 4.92 and 95% CI: 1.67 to 14.5) and transfer out (AHR 2.70 and 95% CI: 1.75 to 4.17) as final outcome. Conclusions: Early tracing substantially reduces LTFU; approximately one-third presumed LTFU was found to be still on ART. Children with wasting at initiation and those traced and found to have irregular ART intake require targeted interventions. PMID:26218409

Drug Delivery for Peripheral Nerve Regeneration

DTIC Science & Technology

2015-11-01

components are shown in Figure 2. The solvent casting method was used for manufacturing devices, with the 75/25 PLGA pellets dissolved in acetone at a...bottom-up process that minimizes wrinkling of the sheet as it expands and contracts. Following 4 hours on a hot plate, the sheet was submerged into...glass transition temperature (40-60°C), eliminating many traditional sterilization methods like autoclaving. We evaluated deformation of the device

Proteomics goes forensic: Detection and mapping of blood signatures in fingermarks.

PubMed

Deininger, Lisa; Patel, Ekta; Clench, Malcolm R; Sears, Vaughn; Sammon, Chris; Francese, Simona

2016-06-01

A bottom up in situ proteomic method has been developed enabling the mapping of multiple blood signatures on the intact ridges of blood fingermarks by Matrix Assisted Laser Desorption Mass Spectrometry Imaging (MALDI-MSI). This method, at a proof of concept stage, builds upon recently published work demonstrating the opportunity to profile and identify multiple blood signatures in bloodstains via a bottom up proteomic approach. The present protocol addresses the limitation of the previously developed profiling method with respect to destructivity; destructivity should be avoided for evidence such as blood fingermarks, where the ridge detail must be preserved in order to provide the associative link between the biometric information and the events of bloodshed. Using a blood mark reference model, trypsin concentration and spraying conditions have been optimised within the technical constraints of the depositor eventually employed; the application of MALDI-MSI and Ion Mobility MS have enabled the detection, confirmation and visualisation of blood signatures directly onto the ridge pattern. These results are to be considered a first insight into a method eventually informing investigations (and judicial debates) of violent crimes in which the reliable and non-destructive detection and mapping of blood in fingermarks is paramount to reconstruct the events of bloodshed. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Method for photolithographic definition of recessed features on a semiconductor wafer utilizing auto-focusing alignment

DOEpatents

Farino, A.J.; Montague, S.; Sniegowski, J.J.; Smith, J.H.; McWhorter, P.J.

1998-07-21

A method is disclosed for photolithographically defining device features up to the resolution limit of an auto-focusing projection stepper when the device features are to be formed in a wafer cavity at a depth exceeding the depth of focus of the stepper. The method uses a focusing cavity located in a die field at the position of a focusing light beam from the auto-focusing projection stepper, with the focusing cavity being of the same depth as one or more adjacent cavities wherein a semiconductor device is to be formed. The focusing cavity provides a bottom surface for referencing the focusing light beam and focusing the stepper at a predetermined depth below the surface of the wafer, whereat the device features are to be defined. As material layers are deposited in each device cavity to build up a semiconductor structure such as a microelectromechanical system (MEMS) device, the same material layers are deposited in the focusing cavity, raising the bottom surface and re-focusing the stepper for accurately defining additional device features in each succeeding material layer. The method is especially applicable for forming MEMS devices within a cavity or trench and integrating the MEMS devices with electronic circuitry fabricated on the wafer surface. 15 figs.

Method for photolithographic definition of recessed features on a semiconductor wafer utilizing auto-focusing alignment

DOEpatents

Farino, Anthony J.; Montague, Stephen; Sniegowski, Jeffry J.; Smith, James H.; McWhorter, Paul J.

1998-01-01

A method is disclosed for photolithographically defining device features up to the resolution limit of an auto-focusing projection stepper when the device features are to be formed in a wafer cavity at a depth exceeding the depth of focus of the stepper. The method uses a focusing cavity located in a die field at the position of a focusing light beam from the auto-focusing projection stepper, with the focusing cavity being of the same depth as one or more adjacent cavities wherein a semiconductor device is to be formed. The focusing cavity provides a bottom surface for referencing the focusing light beam and focusing the stepper at a predetermined depth below the surface of the wafer, whereat the device features are to be defined. As material layers are deposited in each device cavity to build up a semiconductor structure such as a microelectromechanical system (MEMS) device, the same material layers are deposited in the focusing cavity, raising the bottom surface and re-focusing the stepper for accurately defining additional device features in each succeeding material layer. The method is especially applicable for forming MEMS devices within a cavity or trench and integrating the MEMS devices with electronic circuitry fabricated on the wafer surface.

Access-enabling architectures : new hybrid multi-modal spatial prototypes towards resource and social sustainability : USDOT Region V Regional University Transportation Center final report.

DOT National Transportation Integrated Search

2016-12-19

The efforts of this project aim to capture and engage these potentials through a design-research method that incorporates a top down, data-driven approach with bottom-up stakeholder perspectives to develop prototypical scenario-based design solutions...

High rate of virological failure and low rate of switching to second-line treatment among adolescents and adults living with HIV on first-line ART in Myanmar, 2005-2015

PubMed Central

Harries, Anthony D.; Kumar, Ajay M. V.; Oo, Myo Minn; Kyaw, Khine Wut Yee; Win, Than; Aung, Thet Ko; Min, Aung Chan; Oo, Htun Nyunt

2017-01-01

Background The number of people living with HIV on antiretroviral treatment (ART) in Myanmar has been increasing rapidly in recent years. This study aimed to estimate rates of virological failure on first-line ART and switching to second-line ART due to treatment failure at the Integrated HIV Care program (IHC). Methods Routinely collected data of all adolescent and adult patients living with HIV who were initiated on first-line ART at IHC between 2005 and 2015 were retrospectively analyzed. The cumulative hazard of virological failure on first-line ART and switching to second-line ART were estimated. Crude and adjusted hazard ratios were calculated using the Cox regression model to identify risk factors associated with the two outcomes. Results Of 23,248 adults and adolescents, 7,888 (34%) were tested for HIV viral load. The incidence rate of virological failure among those tested was 3.2 per 100 person-years follow-up and the rate of switching to second-line ART among all patients was 1.4 per 100 person-years follow-up. Factors associated with virological failure included: being adolescent; being lost to follow-up at least once; having WHO stage 3 and 4 at ART initiation; and having taken first-line ART elsewhere before coming to IHC. Of the 1032 patients who met virological failure criteria, 762 (74%) switched to second-line ART. Conclusions We found high rates of virological failure among one third of patients in the cohort who were tested for viral load. Of those failing virologically on first-line ART, about one quarter were not switched to second-line ART. Routine viral load monitoring, especially for those identified as having a higher risk of treatment failure, should be considered in this setting to detect all patients failing on first-line ART. Strategies also need to be put in place to prevent treatment failure and to treat more of those patients who are actually failing. PMID:28182786

Optimization of mass spectrometric parameters improve the identification performance of capillary zone electrophoresis for single-shot bottom-up proteomics analysis.

PubMed

Zhang, Zhenbin; Dovichi, Norman J

2018-02-25

The effects of MS1 injection time, MS2 injection time, dynamic exclusion time, intensity threshold, and isolation width were investigated on the numbers of peptide and protein identifications for single-shot bottom-up proteomics analysis using CZE-MS/MS analysis of a Xenopus laevis tryptic digest. An electrokinetically pumped nanospray interface was used to couple a linear-polyacrylamide coated capillary to a Q Exactive HF mass spectrometer. A sensitive method that used a 1.4 Th isolation width, 60,000 MS2 resolution, 110 ms MS2 injection time, and a top 7 fragmentation produced the largest number of identifications when the CZE loading amount was less than 100 ng. A programmable autogain control method (pAGC) that used a 1.4 Th isolation width, 15,000 MS2 resolution, 110 ms MS2 injection time, and top 10 fragmentation produced the largest number of identifications for CZE loading amounts greater than 100 ng; 7218 unique peptides and 1653 protein groups were identified from 200 ng by using the pAGC method. The effect of mass spectrometer conditions on the performance of UPLC-MS/MS was also investigated. A fast method that used a 1.4 Th isolation width, 30,000 MS2 resolution, 45 ms MS2 injection time, and top 12 fragmentation produced the largest number of identifications for 200 ng UPLC loading amount (6025 unique peptides and 1501 protein groups). This is the first report where the identification number for CZE surpasses that of the UPLC at the 200 ng loading level. However, more peptides (11476) and protein groups (2378) were identified by using UPLC-MS/MS when the sample loading amount was increased to 2 μg with the fast method. To exploit the fast scan speed of the Q-Exactive HF mass spectrometer, higher sample loading amounts are required for single-shot bottom-up proteomics analysis using CZE-MS/MS. Copyright © 2017 Elsevier B.V. All rights reserved.

Outcomes of antiretroviral treatment programmes in rural Lesotho: health centres and hospitals compared

PubMed Central

Labhardt, Niklaus Daniel; Keiser, Olivia; Sello, Motlalepula; Lejone, Thabo Ishmael; Pfeiffer, Karolin; Davies, Mary-Ann; Egger, Matthias; Ehmer, Jochen; Wandeler, Gilles

2013-01-01

Introduction Lesotho was among the first countries to adopt decentralization of care from hospitals to nurse-led health centres (HCs) to scale up the provision of antiretroviral therapy (ART). We compared outcomes between patients who started ART at HCs and hospitals in two rural catchment areas in Lesotho. Methods The two catchment areas comprise two hospitals and 12 HCs. Patients ≥16 years starting ART at a hospital or HC between 2008 and 2011 were included. Loss to follow-up (LTFU) was defined as not returning to the facility for ≥180 days after the last visit, no follow-up (no FUP) as not returning after starting ART, and retention in care as alive and on ART at the facility. The data were analysed using logistic regression, competing risk regression and Kaplan-Meier methods. Multivariable analyses were adjusted for sex, age, CD4 cell count, World Health Organization stage, catchment area and type of ART. All analyses were stratified by gender. Results Of 3747 patients, 2042 (54.5%) started ART at HCs. Both women and men at hospitals had more advanced clinical and immunological stages of disease than those at HCs. Over 5445 patient-years, 420 died and 475 were LTFU. Kaplan-Meier estimates for three-year retention were 68.7 and 69.7% at HCs and hospitals, respectively, among women (p=0.81) and 68.8% at HCs versus 54.7% at hospitals among men (p<0.001). These findings persisted in adjusted analyses, with similar retention at HCs and hospitals among women (odds ratio (OR): 0.89, 95% confidence interval (CI): 0.73–1.09) and higher retention at HCs among men (OR: 1.53, 95% CI: 1.20–1.96). The latter result was mainly driven by a lower proportion of patients LTFU at HCs (OR: 0.68, 95% CI: 0.51–0.93). Conclusions In rural Lesotho, overall retention in care did not differ significantly between nurse-led HCs and hospitals. However, men seemed to benefit most from starting ART at HCs, as they were more likely to remain in care in these facilities compared to hospitals. PMID:24267671

Factors Associated with Timing of Initiation of Antiretroviral Therapy among HIV-1 Infected Adults in the Niger Delta Region of Nigeria

PubMed Central

Ogoina, Dimie

2015-01-01

Introduction Based on growing evidence mainly from countries outside Sub-Saharan Africa, the World Health Organisation (WHO) now recommends initiation of antiretroviral therapy (ART) in HIV-infected individuals in developing countries when CD4 cell count (CD4+) is ≤ 500cells/ul. Nigeria accounts for about 14% of the estimated HIV/AIDS burden in Sub-Saharan Africa. We evaluated the factors associated with timing of initiation of ART among treatment-ineligible HIV-infected adults from Nigeria. Methods We retrospectively reviewed the hospital records of ART ineligible HIV-infected adults who enrolled into HIV care between January 2008 and December 2012 at two major tertiary hospitals in Bayelsa State, South-South Nigeria. Demographic, clinical and laboratories data were obtained at presentation, at each subsequent visit at 6 monthly intervals and at time of initiation of ART. Cox proportional regression and Kaplan-Meier survival analysis were used to evaluate independent predictors of time to initiation of ART. Results Amongst the 280 study participants, 70.6% were females, 62.6% had CD4+ ≥500cells/ul, 48.4% had WHO HIV Stage 1 disease and 34.3% were lost to follow up. In a cohort of 180 participants followed up for ≥3months, participants with CD4+ of 351-500cells/ul and stage 2 disease were more likely to start ART earlier than those with CD4+ > 500cells/ul (Hazard ratio [HR]-1.7, 95% confidence interval [CI] of 1.0-2.9) and stage 1 disease (HR-2.3 (95% CI-1.3-4.2) respectively. HIV-infected adults with faster CD4+ decay required earlier ART initiation, especially in the first year of follow up. Conclusion ART-ineligible HIV-infected adults on follow up in South-South Nigeria are more likely to require earlier initiation of ART if they have stage 2 HIV disease or CD4+ ≤500cells/ul at presentation. Our findings suggest faster progression of HIV-disease in these groups of individuals and corroborate the growing evidence in support for earlier initiation of ART. PMID:25933356

The updated bottom up solution applied to atmospheric pressure photoionization and electrospray ionization mass spectrometry

USDA-ARS?s Scientific Manuscript database

The Updated Bottom Up Solution (UBUS) was recently applied to atmospheric pressure chemical ionization (APCI) mass spectrometry (MS) of triacylglycerols (TAGs). This report demonstrates that the UBUS applies equally well to atmospheric pressure photoionization (APPI) MS and to electrospray ionizatio...

Achieving Campus Sustainability: Top-Down, Bottom-Up, or Neither?

ERIC Educational Resources Information Center

Brinkhurst, Marena; Rose, Peter; Maurice, Gillian; Ackerman, Josef Daniel

2011-01-01

Purpose: The dynamics of organizational change related to environmental sustainability on university campuses are examined in this article. Whereas case studies of campus sustainability efforts tend to classify leadership as either "top-down" or "bottom-up", this classification neglects consideration of the leadership roles of…

Bottom-Up Engineering of Well-Defined 3D Microtissues Using Microplatforms and Biomedical Applications.

PubMed

Lee, Geon Hui; Lee, Jae Seo; Wang, Xiaohong; Lee, Sang Hoon

2016-01-07

During the last decades, the engineering of well-defined 3D tissues has attracted great attention because it provides in vivo mimicking environment and can be a building block for the engineering of bioartificial organs. In this Review, diverse engineering methods of 3D tissues using microscale devices are introduced. Recent progress of microtechnologies has enabled the development of microplatforms for bottom-up assembly of diverse shaped 3D tissues consisting of various cells. Micro hanging-drop plates, microfluidic chips, and arrayed microwells are the typical examples. The encapsulation of cells in hydrogel microspheres and microfibers allows the engineering of 3D microtissues with diverse shapes. Applications of 3D microtissues in biomedical fields are described, and the future direction of microplatform-based engineering of 3D micro-tissues is discussed. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Sequential bottom-up assembly of mechanically stabilized synthetic cells by microfluidics

NASA Astrophysics Data System (ADS)

Weiss, Marian; Frohnmayer, Johannes Patrick; Benk, Lucia Theresa; Haller, Barbara; Janiesch, Jan-Willi; Heitkamp, Thomas; Börsch, Michael; Lira, Rafael B.; Dimova, Rumiana; Lipowsky, Reinhard; Bodenschatz, Eberhard; Baret, Jean-Christophe; Vidakovic-Koch, Tanja; Sundmacher, Kai; Platzman, Ilia; Spatz, Joachim P.

2018-01-01

Compartments for the spatially and temporally controlled assembly of biological processes are essential towards cellular life. Synthetic mimics of cellular compartments based on lipid-based protocells lack the mechanical and chemical stability to allow their manipulation into a complex and fully functional synthetic cell. Here, we present a high-throughput microfluidic method to generate stable, defined sized liposomes termed `droplet-stabilized giant unilamellar vesicles (dsGUVs)’. The enhanced stability of dsGUVs enables the sequential loading of these compartments with biomolecules, namely purified transmembrane and cytoskeleton proteins by microfluidic pico-injection technology. This constitutes an experimental demonstration of a successful bottom-up assembly of a compartment with contents that would not self-assemble to full functionality when simply mixed together. Following assembly, the stabilizing oil phase and droplet shells are removed to release functional self-supporting protocells to an aqueous phase, enabling them to interact with physiologically relevant matrices.

Bottom-up synthesis of multifunctional nanoporous graphene

NASA Astrophysics Data System (ADS)

Moreno, César; Vilas-Varela, Manuel; Kretz, Bernhard; Garcia-Lekue, Aran; Costache, Marius V.; Paradinas, Markos; Panighel, Mirko; Ceballos, Gustavo; Valenzuela, Sergio O.; Peña, Diego; Mugarza, Aitor

2018-04-01

Nanosize pores can turn semimetallic graphene into a semiconductor and, from being impermeable, into the most efficient molecular-sieve membrane. However, scaling the pores down to the nanometer, while fulfilling the tight structural constraints imposed by applications, represents an enormous challenge for present top-down strategies. Here we report a bottom-up method to synthesize nanoporous graphene comprising an ordered array of pores separated by ribbons, which can be tuned down to the 1-nanometer range. The size, density, morphology, and chemical composition of the pores are defined with atomic precision by the design of the molecular precursors. Our electronic characterization further reveals a highly anisotropic electronic structure, where orthogonal one-dimensional electronic bands with an energy gap of ∼1 electron volt coexist with confined pore states, making the nanoporous graphene a highly versatile semiconductor for simultaneous sieving and electrical sensing of molecular species.

Numerical modeling of marine Gravity data for tsunami hazard zone mapping

NASA Astrophysics Data System (ADS)

Porwal, Nipun

2012-07-01

Tsunami is a series of ocean wave with very high wavelengths ranges from 10 to 500 km. Therefore tsunamis act as shallow water waves and hard to predict from various methods. Bottom Pressure Recorders of Poseidon class considered as a preeminent method to detect tsunami waves but Acoustic Modem in Ocean Bottom Pressure (OBP) sensors placed in the vicinity of trenches having depth of more than 6000m fails to propel OBP data to Surface Buoys. Therefore this paper is developed for numerical modeling of Gravity field coefficients from Bureau Gravimetric International (BGI) which do not play a central role in the study of geodesy, satellite orbit computation, & geophysics but by mathematical transformation of gravity field coefficients using Normalized Legendre Polynomial high resolution ocean bottom pressure (OBP) data is generated. Real time sea level monitored OBP data of 0.3° by 1° spatial resolution using Kalman filter (kf080) for past 10 years by Estimating the Circulation and Climate of the Ocean (ECCO) has been correlated with OBP data from gravity field coefficients which attribute a feasible study on future tsunami detection system from space and in identification of most suitable sites to place OBP sensors near deep trenches. The Levitus Climatological temperature and salinity are assimilated into the version of the MITGCM using the ad-joint method to obtain the sea height segment. Then TOPEX/Poseidon satellite altimeter, surface momentum, heat, and freshwater fluxes from NCEP reanalysis product and the dynamic ocean topography DOT_DNSCMSS08_EGM08 is used to interpret sea-bottom elevation. Then all datasets are associated under raster calculator in ArcGIS 9.3 using Boolean Intersection Algebra Method and proximal analysis tools with high resolution sea floor topographic map. Afterward tsunami prone area and suitable sites for set up of BPR as analyzed in this research is authenticated by using Passive microwave radiometry system for Tsunami Hazard Zone Mapping by network of seismometers. Thus using such methodology for early Tsunami Hazard Zone Mapping also increase accuracy and reduce time period for tsunami predictions. KEYWORDS:, Tsunami, Gravity Field Coefficients, Ocean Bottom Pressure, ECCO, BGI, Sea Bottom Temperature, Sea Floor Topography.

Pressurized Pepsin Digestion in Proteomics

PubMed Central

López-Ferrer, Daniel; Petritis, Konstantinos; Robinson, Errol W.; Hixson, Kim K.; Tian, Zhixin; Lee, Jung Hwa; Lee, Sang-Won; Tolić, Nikola; Weitz, Karl K.; Belov, Mikhail E.; Smith, Richard D.; Paša-Tolić, Ljiljana

2011-01-01

Integrated top-down bottom-up proteomics combined with on-line digestion has great potential to improve the characterization of protein isoforms in biological systems and is amendable to high throughput proteomics experiments. Bottom-up proteomics ultimately provides the peptide sequences derived from the tandem MS analyses of peptides after the proteome has been digested. Top-down proteomics conversely entails the MS analyses of intact proteins for more effective characterization of genetic variations and/or post-translational modifications. Herein, we describe recent efforts toward efficient integration of bottom-up and top-down LC-MS-based proteomics strategies. Since most proteomics separations utilize acidic conditions, we exploited the compatibility of pepsin (where the optimal digestion conditions are at low pH) for integration into bottom-up and top-down proteomics work flows. Pressure-enhanced pepsin digestions were successfully performed and characterized with several standard proteins in either an off-line mode using a Barocycler or an on-line mode using a modified high pressure LC system referred to as a fast on-line digestion system (FOLDS). FOLDS was tested using pepsin and a whole microbial proteome, and the results were compared against traditional trypsin digestions on the same platform. Additionally, FOLDS was integrated with a RePlay configuration to demonstrate an ultrarapid integrated bottom-up top-down proteomics strategy using a standard mixture of proteins and a monkey pox virus proteome. PMID:20627868

Variability at Multiple Scales: Using an Array of Current and Pressure Sensor Equipped Inverted Echo Sounders to Measure the Ocean

DTIC Science & Technology

2016-11-29

travel time between the seafloor and the sea surface; bottom pressure and temperature; and near-bottom horizontal currents hourly for up to 5 years...pressure and current sensors (CPIESs). CPIESs (Figure 1) are moored instruments that measure (1) the round-trip acoustic travel time between the...measurements of surface-to-bottom round-trip acoustic- travel time (’c), bottom pressure and temperature, and near-bottom horizontal currents

Variability at Multiple Scales: Using an Array of Current- and Pressure-Sensor Equipped Inverted Echo Sounders to Measure the Ocean

DTIC Science & Technology

2016-11-29

travel time between the seafloor and the sea surface; bottom pressure and temperature; and near-bottom horizontal currents hourly for up to 5 years...pressure and current sensors (CPIESs). CPIESs (Figure 1) are moored instruments that measure (1) the round-trip acoustic travel time between the...measurements of surface-to-bottom round-trip acoustic- travel time (’c), bottom pressure and temperature, and near-bottom horizontal currents

An Analysis Model for Water Cone Subsidence in Bottom Water Drive Reservoirs

NASA Astrophysics Data System (ADS)

Wang, Jianjun; Xu, Hui; Wu, Shucheng; Yang, Chao; Kong, lingxiao; Zeng, Baoquan; Xu, Haixia; Qu, Tailai

2017-12-01

Water coning in bottom water drive reservoirs, which will result in earlier water breakthrough, rapid increase in water cut and low recovery level, has drawn tremendous attention in petroleum engineering field. As one simple and effective method to inhibit bottom water coning, shut-in coning control is usually preferred in oilfield to control the water cone and furthermore to enhance economic performance. However, most of the water coning researchers just have been done on investigation of the coning behavior as it grows up, the reported studies for water cone subsidence are very scarce. The goal of this work is to present an analytical model for water cone subsidence to analyze the subsidence of water cone when the well shut in. Based on Dupuit critical oil production rate formula, an analytical model is developed to estimate the initial water cone shape at the point of critical drawdown. Then, with the initial water cone shape equation, we propose an analysis model for water cone subsidence in bottom water reservoir reservoirs. Model analysis and several sensitivity studies are conducted. This work presents accurate and fast analytical model to perform the water cone subsidence in bottom water drive reservoirs. To consider the recent interests in development of bottom drive reservoirs, our approach provides a promising technique for better understanding the subsidence of water cone.

Merging Bottom-Up with Top-Down: Continuous Lamellar Networks and Block Copolymer Lithography

NASA Astrophysics Data System (ADS)

Campbell, Ian Patrick

Block copolymer lithography is an emerging nanopatterning technology with capabilities that may complement and eventually replace those provided by existing optical lithography techniques. This bottom-up process relies on the parallel self-assembly of macromolecules composed of covalently linked, chemically distinct blocks to generate periodic nanostructures. Among the myriad potential morphologies, lamellar structures formed by diblock copolymers with symmetric volume fractions have attracted the most interest as a patterning tool. When confined to thin films and directed to assemble with interfaces perpendicular to the substrate, two-dimensional domains are formed between the free surface and the substrate, and selective removal of a single block creates a nanostructured polymeric template. The substrate exposed between the polymeric features can subsequently be modified through standard top-down microfabrication processes to generate novel nanostructured materials. Despite tremendous progress in our understanding of block copolymer self-assembly, continuous two-dimensional materials have not yet been fabricated via this robust technique, which may enable nanostructured material combinations that cannot be fabricated through bottom-up methods. This thesis aims to study the effects of block copolymer composition and processing on the lamellar network morphology of polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) and utilize this knowledge to fabricate continuous two-dimensional materials through top-down methods. First, block copolymer composition was varied through homopolymer blending to explore the physical phenomena surrounding lamellar network continuity. After establishing a framework for tuning the continuity, the effects of various processing parameters were explored to engineer the network connectivity via defect annihilation processes. Precisely controlling the connectivity and continuity of lamellar networks through defect engineering and optimizing the block copolymer lithography process thus enabled the top-down fabrication of continuous two-dimensional gold networks with nanoscale properties. The lamellar structure of these networks was found to confer unique mechanical properties on the nanowire networks and suggests that materials templated via this method may be excellent candidates for integration into stretchable and flexible devices.

The probabilistic convolution tree: efficient exact Bayesian inference for faster LC-MS/MS protein inference.

PubMed

Serang, Oliver

2014-01-01

Exact Bayesian inference can sometimes be performed efficiently for special cases where a function has commutative and associative symmetry of its inputs (called "causal independence"). For this reason, it is desirable to exploit such symmetry on big data sets. Here we present a method to exploit a general form of this symmetry on probabilistic adder nodes by transforming those probabilistic adder nodes into a probabilistic convolution tree with which dynamic programming computes exact probabilities. A substantial speedup is demonstrated using an illustration example that can arise when identifying splice forms with bottom-up mass spectrometry-based proteomics. On this example, even state-of-the-art exact inference algorithms require a runtime more than exponential in the number of splice forms considered. By using the probabilistic convolution tree, we reduce the runtime to O(k log(k)2) and the space to O(k log(k)) where k is the number of variables joined by an additive or cardinal operator. This approach, which can also be used with junction tree inference, is applicable to graphs with arbitrary dependency on counting variables or cardinalities and can be used on diverse problems and fields like forward error correcting codes, elemental decomposition, and spectral demixing. The approach also trivially generalizes to multiple dimensions.

The Probabilistic Convolution Tree: Efficient Exact Bayesian Inference for Faster LC-MS/MS Protein Inference

PubMed Central

Serang, Oliver

2014-01-01

Exact Bayesian inference can sometimes be performed efficiently for special cases where a function has commutative and associative symmetry of its inputs (called “causal independence”). For this reason, it is desirable to exploit such symmetry on big data sets. Here we present a method to exploit a general form of this symmetry on probabilistic adder nodes by transforming those probabilistic adder nodes into a probabilistic convolution tree with which dynamic programming computes exact probabilities. A substantial speedup is demonstrated using an illustration example that can arise when identifying splice forms with bottom-up mass spectrometry-based proteomics. On this example, even state-of-the-art exact inference algorithms require a runtime more than exponential in the number of splice forms considered. By using the probabilistic convolution tree, we reduce the runtime to and the space to where is the number of variables joined by an additive or cardinal operator. This approach, which can also be used with junction tree inference, is applicable to graphs with arbitrary dependency on counting variables or cardinalities and can be used on diverse problems and fields like forward error correcting codes, elemental decomposition, and spectral demixing. The approach also trivially generalizes to multiple dimensions. PMID:24626234

Saliency Detection via Absorbing Markov Chain With Learnt Transition Probability.

PubMed

Lihe Zhang; Jianwu Ai; Bowen Jiang; Huchuan Lu; Xiukui Li

2018-02-01

In this paper, we propose a bottom-up saliency model based on absorbing Markov chain (AMC). First, a sparsely connected graph is constructed to capture the local context information of each node. All image boundary nodes and other nodes are, respectively, treated as the absorbing nodes and transient nodes in the absorbing Markov chain. Then, the expected number of times from each transient node to all other transient nodes can be used to represent the saliency value of this node. The absorbed time depends on the weights on the path and their spatial coordinates, which are completely encoded in the transition probability matrix. Considering the importance of this matrix, we adopt different hierarchies of deep features extracted from fully convolutional networks and learn a transition probability matrix, which is called learnt transition probability matrix. Although the performance is significantly promoted, salient objects are not uniformly highlighted very well. To solve this problem, an angular embedding technique is investigated to refine the saliency results. Based on pairwise local orderings, which are produced by the saliency maps of AMC and boundary maps, we rearrange the global orderings (saliency value) of all nodes. Extensive experiments demonstrate that the proposed algorithm outperforms the state-of-the-art methods on six publicly available benchmark data sets.

Free-Form Region Description with Second-Order Pooling.

PubMed

Carreira, João; Caseiro, Rui; Batista, Jorge; Sminchisescu, Cristian

2015-06-01

Semantic segmentation and object detection are nowadays dominated by methods operating on regions obtained as a result of a bottom-up grouping process (segmentation) but use feature extractors developed for recognition on fixed-form (e.g. rectangular) patches, with full images as a special case. This is most likely suboptimal. In this paper we focus on feature extraction and description over free-form regions and study the relationship with their fixed-form counterparts. Our main contributions are novel pooling techniques that capture the second-order statistics of local descriptors inside such free-form regions. We introduce second-order generalizations of average and max-pooling that together with appropriate non-linearities, derived from the mathematical structure of their embedding space, lead to state-of-the-art recognition performance in semantic segmentation experiments without any type of local feature coding. In contrast, we show that codebook-based local feature coding is more important when feature extraction is constrained to operate over regions that include both foreground and large portions of the background, as typical in image classification settings, whereas for high-accuracy localization setups, second-order pooling over free-form regions produces results superior to those of the winning systems in the contemporary semantic segmentation challenges, with models that are much faster in both training and testing.

Empathy and the aesthetic: Why does art still move us?

PubMed

Stamatopoulou, Despina

2018-05-01

In this article I will argue for the affective-motivation (background affective attitude or orientation) hypothesis that incubates the aesthetic experience and sets the deep frame of our engagement with art. For this, I look at these microgenetic-early passages of (a) affective perception as mapped into the early emergence of tertiary qualities that underlie a sensorimotor synchronization-a coupling of action, emotion and perception via mirroring that result in dynamic embodied anticipatory control and a feeling of proximity/connectedness and (b) developmental passages that are characterized by spatiotemporal coordination and proximity of the self-other/interactive object and thus structure intentionality, shape experience, in an engaging world of action potentialities forming a background affective attitude. As I will argue these qualitative emergent layers provide the minimal for the aesthetic and the 'feeling into' empathy, or their phenomenological counterparts enable engaged, embodied perception and imagination underlying expressive symbolic communication in interpersonal settings but also for the possibility of art. These layers have an 'echoing' effect (pre-attentive) when we let ourselves to be 'moved' from within by art. The underlying mechanism could be found in the mirroring interface of the upcoming bottom-up and feeding forward anticipatory/predictive (top-down) function of the 'embodied action' representations that are affective, imitative and grounded in the body-affective matrix-carrying experiential affordances and keeping the intersubjective ties between spectator and beheld/object. Given the asymmetry on action tendency between them that affords the 'subordination of the goal-directed action' into to the means of the action's unfolding, aesthetic experiences can go deeply back reconstructing the first level of emerging consciousness where both the aesthetic and ethic became actualities. This could be by itself deeply rewarding, amplifying the experience to the 'edge'. This is a 'hot' cognition self-restructuring related to morality when facing the sufferings-so there might be something special bout art and negative emotions in relation to empathy.

Analytics that Inform the University: Using Data You Already Have

ERIC Educational Resources Information Center

Dziuban, Charles; Moskal, Patsy; Cavanagh, Thomas; Watts, Andre

2012-01-01

The authors describe the University of Central Florida's top-down/bottom-up action analytics approach to using data to inform decision-making at the University of Central Florida. The top-down approach utilizes information about programs, modalities, and college implementation of Web initiatives. The bottom-up approach continuously monitors…

Effects of Bottom-up and Top-down Controls and Climate Change on Estuarine Macrophyte Communities and the Ecosystem Services they Provide

EPA Science Inventory

Macrophytes provide important estuarine benthic habitats and support a significant portion of estuarine productivity. The composition and characteristics of these benthic communities are regulated bottom-up by resource availability and from the top-down by herbivory and predation...

Dancing on the Bottom Line: An Unruly Cost-Benefit Analysis of Three Academic Development Initiatives

ERIC Educational Resources Information Center

Sword, Helen

2014-01-01

This article offers an unconventional cost-benefit analysis of three academic development initiatives at a large Australasian university: a three-day foundation course for new academics, a series of one-on-one teaching consultations and a two-year postgraduate certificate program. Weaving together qualitative, quantitative and arts-based…

The Best University Degrees to Get a Job

ERIC Educational Resources Information Center

Furnham, Adrian; Pertrides, K. V.

2010-01-01

Nearly 500 members of the public rated 20 university degree subjects in terms of their usefulness for employability. The top three were Law, Maths and English whereas the bottom three were Fine Art, Anthropology and Theology. A factor analysis was conducted to group the 20 subjects into broad academic fields. Five factors were identified,…

The Impact of Company-Level ART Provision to a Mining Workforce in South Africa: A Cost-Benefit Analysis.

PubMed

Meyer-Rath, Gesine; Pienaar, Jan; Brink, Brian; van Zyl, Andrew; Muirhead, Debbie; Grant, Alison; Churchyard, Gavin; Watts, Charlotte; Vickerman, Peter

2015-09-01

HIV impacts heavily on the operating costs of companies in sub-Saharan Africa, with many companies now providing antiretroviral therapy (ART) programmes in the workplace. A full cost-benefit analysis of workplace ART provision has not been conducted using primary data. We developed a dynamic health-state transition model to estimate the economic impact of HIV and the cost-benefit of ART provision in a mining company in South Africa between 2003 and 2022. A dynamic health-state transition model, called the Workplace Impact Model (WIM), was parameterised with workplace data on workforce size, composition, turnover, HIV incidence, and CD4 cell count development. Bottom-up cost analyses from the employer perspective supplied data on inpatient and outpatient resource utilisation and the costs of absenteeism and replacement of sick workers. The model was fitted to workforce HIV prevalence and separation data while incorporating parameter uncertainty; univariate sensitivity analyses were used to assess the robustness of the model findings. As ART coverage increases from 10% to 97% of eligible employees, increases in survival and retention of HIV-positive employees and associated reductions in absenteeism and benefit payments lead to cost savings compared to a scenario of no treatment provision, with the annual cost of HIV to the company decreasing by 5% (90% credibility interval [CrI] 2%-8%) and the mean cost per HIV-positive employee decreasing by 14% (90% CrI 7%-19%) by 2022. This translates into an average saving of US$950,215 (90% CrI US$220,879-US$1.6 million) per year; 80% of these cost savings are due to reductions in benefit payments and inpatient care costs. Although findings are sensitive to assumptions regarding incidence and absenteeism, ART is cost-saving under considerable parameter uncertainty and in all tested scenarios, including when prevalence is reduced to 1%-except when no benefits were paid out to employees leaving the workforce and when absenteeism rates were half of what data suggested. Scaling up ART further through a universal test and treat strategy doubles savings; incorporating ART for family members reduces savings but is still marginally cost-saving compared to no treatment. Our analysis was limited to the direct cost of HIV to companies and did not examine the impact of HIV prevention policies on the miners or their families, and a few model inputs were based on limited data, though in sensitivity analysis our results were found to be robust to changes to these inputs along plausible ranges. Workplace ART provision can be cost-saving for companies in high HIV prevalence settings due to reductions in healthcare costs, absenteeism, and staff turnover. Company-sponsored HIV counselling and voluntary testing with ensuing treatment of all HIV-positive employees and family members should be implemented universally at workplaces in countries with high HIV prevalence.

Retention of antiretroviral naïve patients registered in HIV care in a program clinic in Pune, India

PubMed Central

Ghate, Manisha V.; Zirpe, Sunil S.; Gurav, Nilam P.; Rewari, Bharat B.; Gangakhedkar, Raman R.; Paranjape, Ramesh S.

2014-01-01

Background: Retention in HIV care ensures delivery of services like secondary prevention, timely initiation of treatment, support, and care on a regular basis. The data on retention in pre antiretroviral therapy (ART) care in India is scanty. Materials and Methods: Antiretroviral naïve HIV-infected adult patients registered between January 2011 and March 2012 in HIV care (pre-ART) were included in the study. The follow-up procedures were done as per the national guidelines. Patients who did not report to the clinic for 1 year were considered as pre-ART lost to follow-up (pre-ART LFU). They were contacted either telephonically or by home visits. Logistic regression analysis was done to find out factors associated with pre-ART loss to follow-up. Results: A total of 689 antiretroviral naïve adult patients were registered in the HIV care. Fourteen (2%) patients died and 76 (11%) were LFU till March 2013. The multivariate analysis showed that baseline CD4 count >350 cells/mm3 (P < 0.01) and illiteracy (P = 0.044) were significantly associated with LFU. Of the total pre-ART LFUs, 35 (46.1%) informed that they would visit the clinic at their convenient time. NGOs that referred 16 female sex workers (FSWs) who were LFU (21.1%) informed that they would make efforts to refer them to the clinic. Conclusion: Higher CD4 count and illiteracy were significantly associated with lower retention in pre-ART care. Developing effective “retention package” for patients and strengthening linkage strategies between key sub-population such as FSWs and ART programming will help to plug the leaky cascade in HIV care. PMID:26396447

A Physical Mechanism for the Asymmetry in Top-Down and Bottom-Up Diffusion.

NASA Astrophysics Data System (ADS)

Wyngaard, J. C.

1987-04-01

Recent large-eddy simulations of the vertical diffusion of a passive, conservative scalar through the convective boundary layer (CBL) show strikingly different eddy diffusivity profiles in the `top-down' and `bottom-up' cases. These results indicate that for a given turbulent velocity field and associated scalar flux, the mean change in scalar mixing ratio across the CBL is several times larger if the flux originates at the top of the boundary layer (i.e., in top-down diffusion) rather than at the bottom. The large-eddy simulation (LES) data show that this asymmetry is due to a breakdown of the eddy-diffusion concept.A simple updraft-downdraft model of the CBL reveals a physical mechanism that could cause this unexpected behavior. The large, positive skewness of the convectively driven vertical velocity gives an appreciably higher probability of downdrafts than updrafts; this excess probability of downdrafts, interacting with the time changes of the mean mixing ratio caused by the nonstationarity of the bottom-up and top-down diffusion processes, decreases the equilibrium value of mean mixing-ratio jump across the mixed layer in the bottom-up case and increases it in the top-down case. The resulting diffusion asymmetry agrees qualitatively with that found through LES.

Barriers and Facilitators of Adherence to Antiretroviral Drug Therapy and Retention in Care among Adult HIV-Positive Patients: A Qualitative Study from Ethiopia

PubMed Central

Bezabhe, Woldesellassie M.; Chalmers, Leanne; Bereznicki, Luke R.; Peterson, Gregory M.; Bimirew, Mekides A.; Kassie, Desalew M.

2014-01-01

Background Antiretroviral therapy (ART) has been life saving for hundreds of thousands of Ethiopians. With increased availability of ART in recent years, achievement of optimal adherence and patient retention are becoming the greatest challenges in the management of HIV/AIDS in Ethiopia. However, few studies have explored factors influencing medication adherence to ART and retention in follow-up care among adult Ethiopian HIV-positive patients, especially in the Amhara region of the country, where almost one-third of the country’s ART is prescribed. The aim of this qualitative study was to collect such data from patients and healthcare providers in the Amhara region of Ethiopia. Methods Semi-structured interviews were conducted with 24 patients, of whom 11 had been lost to follow-up and were non-persistent with ART. In addition, focus group discussions were performed with 15 ART nurses and 19 case managers. All interviews and focus groups were audio-recorded, transcribed, and coded for themes and patterns in Amharic using a grounded theory approach. The emergent concepts and categories were translated into English. Results Economic constraints, perceived stigma and discrimination, fasting, holy water, medication side effects, and dissatisfaction with healthcare services were major reasons for patients being non-adherent and lost to follow-up. Disclosure of HIV status, social support, use of reminder aids, responsibility for raising children, improved health on ART, and receiving education and counseling emerged as facilitators of adherence to ART. Conclusions Improving adherence and retention requires integration of enhanced treatment access with improved job and food security. Healthcare providers need to be supported to better equip patients to cope with the issues associated with ART. Development of social policies and cooperation between various agencies are required to facilitate optimal adherence to ART, patient retention, and improved patient outcomes. PMID:24828585

Pregnancy rates in HIV-positive women using contraceptives and efavirenz-based or nevirapine-based antiretroviral therapy in Kenya: a retrospective cohort study.

PubMed

Patel, Rena C; Onono, Maricianah; Gandhi, Monica; Blat, Cinthia; Hagey, Jill; Shade, Starley B; Vittinghoff, Eric; Bukusi, Elizabeth A; Newmann, Sara J; Cohen, Craig R

2015-11-01

Concerns have been raised about efavirenz reducing the effectiveness of contraceptive implants. We aimed to establish whether pregnancy rates differ between HIV-positive women who use various contraceptive methods and either efavirenz-based or nevirapine-based antiretroviral therapy (ART) regimens. We did this retrospective cohort study of HIV-positive women aged 15-45 years enrolled in 19 HIV care facilities supported by Family AIDS Care and Education Services in western Kenya between Jan 1, 2011, and Dec 31, 2013. Our primary outcome was incident pregnancy diagnosed clinically. The primary exposure was a combination of contraceptive method and efavirenz-based or nevirapine-based ART regimen. We used Poisson models, adjusting for repeated measures, and demographic, behavioural, and clinical factors, to compare pregnancy rates among women receiving different contraceptive and ART combinations. 24,560 women contributed 37,635 years of follow-up with 3337 incident pregnancies. In women using implants, adjusted pregnancy incidence was 1.1 per 100 person-years (95% CI 0.72-1.5) for nevirapine-based ART users and 3.3 per 100 person-years (1.8-4.8) for efavirenz-based ART users (adjusted incidence rate ratio [IRR] 3.0, 95% CI 1.3-4.6). In women using depot medroxyprogesterone acetate, adjusted pregnancy incidence was 4.5 per 100 person-years (95% CI 3.7-5.2) for nevirapine-based ART users and 5.4 per 100 person-years (4.0-6.8) for efavirenz-based ART users (adjusted IRR 1.2, 95% CI 0.91-1.5). Women using other contraceptive methods, except for intrauterine devices and permanent methods, had 3.1-4.1 higher rates of pregnancy than did those using implants, with 1.6-2.8 higher rates in women using efavirenz-based ART. Although HIV-positive women using implants and efavirenz-based ART had a three-times higher risk of contraceptive failure than did those using nevirapine-based ART, these women still had lower contraceptive failure rates than did those receiving all other contraceptive methods except for intrauterine devices and permanent methods. Guidelines for contraceptive and ART combinations should balance the failure rates for each contraceptive method and ART regimen combination against the high effectiveness of implants. None. Copyright © 2015 Elsevier Ltd. All rights reserved.

Top-down visual search in Wimmelbild

NASA Astrophysics Data System (ADS)

Bergbauer, Julia; Tari, Sibel

2013-03-01

Wimmelbild which means "teeming figure picture" is a popular genre of visual puzzles. Abundant masses of small figures are brought together in complex arrangements to make one scene in a Wimmelbild. It is picture hunt game. We discuss what type of computations/processes could possibly underlie the solution of the discovery of figures that are hidden due to a distractive influence of the context. One thing for sure is that the processes are unlikely to be purely bottom-up. One possibility is to re-arrange parts and see what happens. As this idea is linked to creativity, there are abundant examples of unconventional part re-organization in modern art. A second possibility is to define what to look for. That is to formulate the search as a top-down process. We address top-down visual search in Wimmelbild with the help of diffuse distance and curvature coding fields.

Time to Initiation of Antiretroviral Therapy Among Patients Who Are ART Eligible in Rwanda: Improvement Over Time

PubMed Central

Teasdale, Chloe A.; Wang, Chunhui; Francois, Uwinkindi; d’Amour Ndahimana, Jean; Vincent, Mutabazi; Sahabo, Ruben; El-Sadr, Wafaa M.; Abrams, Elaine J.

2016-01-01

Background Delayed initiation of antiretroviral therapy (ART) in eligible patients is a concern in resource-limited countries. Methods We analyzed data on HIV-positive patients ≥15 years enrolled at 41 ICAP-supported health care facilities in Rwanda, 2005–2010, to determine time to ART initiation among patients eligible at enrollment compared with those ineligible or of indeterminate eligibility who become eligible during follow-up. ART eligibility was based on CD4+ cell count (CD4+) and WHO staging; patients lacking CD4+ and WHO stage were considered indeterminate. Cumulative incidence of reaching ART eligibility and to ART initiation after eligibility was generated using competing risk estimators. Results A total of 31,033 ART-naive adults were enrolled; 64.2% were female. At enrollment, 10,158 (32.7%) patients were ART eligible, 13,372 (43.1%) were ineligible for ART, and 7503 (24.2%) patients were indeterminate. Among patients retained in care pre-ART eligibility, 17.9% [95% confidence interval (CI): 17.2 to 18.6] of ineligible and 22.8% (95% CI: 21.7 to 23.8) of indeterminate patients at enrollment reached ART eligibility within 12 months. Cumulative incidence of ART initiation within 3 months for patients eligible at enrollment was 77.2% (95% CI: 76.4 to 78.0) compared with 67.9% (95% CI: 66.4 to 69.3) for ineligible and 63.8% (95% CI: 61.9 to 65.8) for patients with indeterminate eligibility at enrollment (P < 0.05). Over the study period, there was more rapid ART initiation for patients who became ART eligible. Conclusions We found higher rates of ART initiation within 3 months among patients who were ART eligible at enrollment compared with those who reached eligibility during follow-up. From 2006 to 2011, earlier initiation of ART after eligibility was observed likely reflecting improved program quality. PMID:25415291

Figure-ground organization and object recognition processes: an interactive account.

PubMed

Vecera, S P; O'Reilly, R C

1998-04-01

Traditional bottom-up models of visual processing assume that figure-ground organization precedes object recognition. This assumption seems logically necessary: How can object recognition occur before a region is labeled as figure? However, some behavioral studies find that familiar regions are more likely to be labeled figure than less familiar regions, a problematic finding for bottom-up models. An interactive account is proposed in which figure-ground processes receive top-down input from object representations in a hierarchical system. A graded, interactive computational model is presented that accounts for behavioral results in which familiarity effects are found. The interactive model offers an alternative conception of visual processing to bottom-up models.

Addressing the Misuse Potential of Life Science Research-Perspectives From a Bottom-Up Initiative in Switzerland.

PubMed

Oeschger, Franziska M; Jenal, Ursula

2018-01-01

Codes of conduct have received wide attention as a bottom-up approach to foster responsibility for dual use aspects of life science research within the scientific community. In Switzerland, a series of discussion sessions led by the Swiss Academy of Sciences with over 40 representatives of most Swiss academic life science research institutions has revealed that while a formal code of conduct was considered too restrictive, a bottom-up approach toward awareness raising and education and demonstrating scientists' responsibility toward society was highly welcomed. Consequently, an informational brochure on "Misuse potential and biosecurity in life sciences research" was developed to provide material for further discussions and education.

Costing Hospital Surgery Services: The Method Matters

PubMed Central

Mercier, Gregoire; Naro, Gerald

2014-01-01

Background Accurate hospital costs are required for policy-makers, hospital managers and clinicians to improve efficiency and transparency. However, different methods are used to allocate direct costs, and their agreement is poorly understood. The aim of this study was to assess the agreement between bottom-up and top-down unit costs of a large sample of surgical operations in a French tertiary centre. Methods Two thousand one hundred and thirty consecutive procedures performed between January and October 2010 were analysed. Top-down costs were based on pre-determined weights, while bottom-up costs were calculated through an activity-based costing (ABC) model. The agreement was assessed using correlation coefficients and the Bland and Altman method. Variables associated with the difference between methods were identified with bivariate and multivariate linear regressions. Results The correlation coefficient amounted to 0.73 (95%CI: 0.72; 0.76). The overall agreement between methods was poor. In a multivariate analysis, the cost difference was independently associated with age (Beta = −2.4; p = 0.02), ASA score (Beta = 76.3; p<0.001), RCI (Beta = 5.5; p<0.001), staffing level (Beta = 437.0; p<0.001) and intervention duration (Beta = −10.5; p<0.001). Conclusions The ability of the current method to provide relevant information to managers, clinicians and payers is questionable. As in other European countries, a shift towards time-driven activity-based costing should be advocated. PMID:24817167

Statistical modeling of isoform splicing dynamics from RNA-seq time series data.

PubMed

Huang, Yuanhua; Sanguinetti, Guido

2016-10-01

Isoform quantification is an important goal of RNA-seq experiments, yet it remains problematic for genes with low expression or several isoforms. These difficulties may in principle be ameliorated by exploiting correlated experimental designs, such as time series or dosage response experiments. Time series RNA-seq experiments, in particular, are becoming increasingly popular, yet there are no methods that explicitly leverage the experimental design to improve isoform quantification. Here, we present DICEseq, the first isoform quantification method tailored to correlated RNA-seq experiments. DICEseq explicitly models the correlations between different RNA-seq experiments to aid the quantification of isoforms across experiments. Numerical experiments on simulated datasets show that DICEseq yields more accurate results than state-of-the-art methods, an advantage that can become considerable at low coverage levels. On real datasets, our results show that DICEseq provides substantially more reproducible and robust quantifications, increasing the correlation of estimates from replicate datasets by up to 10% on genes with low or moderate expression levels (bottom third of all genes). Furthermore, DICEseq permits to quantify the trade-off between temporal sampling of RNA and depth of sequencing, frequently an important choice when planning experiments. Our results have strong implications for the design of RNA-seq experiments, and offer a novel tool for improved analysis of such datasets. Python code is freely available at http://diceseq.sf.net G.Sanguinetti@ed.ac.uk Supplementary data are available at Bioinformatics online. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Hierarchical time series bottom-up approach for forecast the export value in Central Java

NASA Astrophysics Data System (ADS)

Mahkya, D. A.; Ulama, B. S.; Suhartono

2017-10-01

The purpose of this study is Getting the best modeling and predicting the export value of Central Java using a Hierarchical Time Series. The export value is one variable injection in the economy of a country, meaning that if the export value of the country increases, the country’s economy will increase even more. Therefore, it is necessary appropriate modeling to predict the export value especially in Central Java. Export Value in Central Java are grouped into 21 commodities with each commodity has a different pattern. One approach that can be used time series is a hierarchical approach. Hierarchical Time Series is used Buttom-up. To Forecast the individual series at all levels using Autoregressive Integrated Moving Average (ARIMA), Radial Basis Function Neural Network (RBFNN), and Hybrid ARIMA-RBFNN. For the selection of the best models used Symmetric Mean Absolute Percentage Error (sMAPE). Results of the analysis showed that for the Export Value of Central Java, Bottom-up approach with Hybrid ARIMA-RBFNN modeling can be used for long-term predictions. As for the short and medium-term predictions, it can be used a bottom-up approach RBFNN modeling. Overall bottom-up approach with RBFNN modeling give the best result.

Untangling the Relationship Between Antiretroviral Therapy Use and Incident Pregnancy: A Marginal Structural Model Analysis Using Data From 47,313 HIV-Positive Women in East Africa

PubMed Central

Wools-Kaloustian, Kara K.; Wu, Yingfeng; Musick, Beverly S.; Nuwagaba-Biribonwoha, Harriet; Nash, Denis; Ayaya, Samuel; Bukusi, Elizabeth; Okong, Pius; Otieno, Juliana; Wabwire, Deo; Kambugu, Andrew; Yiannoutsos, Constantin T.

2016-01-01

Background: Scale-up of triple-drug antiretroviral therapy (ART) in Africa has transformed the context of childbearing for HIV-positive women and may impact pregnancy incidence in HIV programs. Methods: Using observational data from 47,313 HIV-positive women enrolled at 26 HIV clinics in Kenya and Uganda between 2001 and 2009, we calculated the crude cumulative incidence of pregnancy for the pre-ART and on-ART periods. The causal effect of ART use on incident pregnancy was assessed using inverse probability weighted marginal structural models, and the relationship was further explored in multivariable Cox models. Results: Crude cumulative pregnancy incidence at 1 year after enrollment/ART initiation was 4.0% and 3.9% during the pre-ART and on-ART periods, respectively. In marginal structural models, ART use was not significantly associated with incident pregnancy [hazard ratio = 1.06; 95% confidence interval (CI): 0.99 to 1.12]. Similarly, in Cox models, there was no significant relationship between ART use and incident pregnancy (cause-specific hazard ratio: 0.98; 95% CI: 0.91 to 1.05), but effect modification was observed. Specifically, women who were pregnant at enrollment and on ART had an increased risk of incident pregnancy compared to those not pregnant at enrollment and not on ART (cause-specific hazard ratio: 1.11; 95% CI: 1.01 to 1.23). Conclusions: In this large cohort, ART initiation was not associated with incident pregnancy in the general population of women enrolling in HIV care but rather only among those pregnant at enrollment. This finding further highlights the importance of scaling up access to lifelong treatment for pregnant women. PMID:26910499

Anatomical Remodeling of Buccal Bone Plate in 35 Premaxillary Post-Extraction Immediately Restored Single TPS Implants: 10-Year Radiographic Investigation.

PubMed

Quaranta, Alessandro; Perrotti, Vittoria; Putignano, Angelo; Malchiodi, Luciano; Vozza, Iole; Calvo Guirado, José Luis

2016-04-01

The anatomical remodeling technique (ART) was proposed to place postextraction implants with the aid of specific osteotomes. This study is a clinical and radiographic evaluation with 10-year follow-up of anterior postextraction single implants placed with the ART and immediately restored. Thirty-five patients, with a hopeless tooth in the anterior maxilla, were included in the study and 35 implants were inserted according to the ART. Clinical and radiographic evaluations were performed at baseline (T0), after 6 (T1) and 14 months (T2), 4 years after surgery (T3) and every other year up to the 10-year follow-up (T4, T5, and T6). Implant success, survival, and failure rates were evaluated according to the International Congress of Oral Implantologists Pisa Consensus Conference criteria. Twenty-nine patients and 29 implants were available for the 10-year data analysis. After 10 years, the accumulated mean marginal bone loss was 2.69 ± 0.42 mm. The cumulative survival rate of the implants was 100%. Immediately loaded postextractive implants, placed according to the ART, have been proved to be a predictable method to rehabilitate single tooth in the anterior maxilla.

QBIC project: querying images by content, using color, texture, and shape

NASA Astrophysics Data System (ADS)

Niblack, Carlton W.; Barber, Ron; Equitz, Will; Flickner, Myron D.; Glasman, Eduardo H.; Petkovic, Dragutin; Yanker, Peter; Faloutsos, Christos; Taubin, Gabriel

1993-04-01

In the query by image content (QBIC) project we are studying methods to query large on-line image databases using the images' content as the basis of the queries. Examples of the content we use include color, texture, and shape of image objects and regions. Potential applications include medical (`Give me other images that contain a tumor with a texture like this one'), photo-journalism (`Give me images that have blue at the top and red at the bottom'), and many others in art, fashion, cataloging, retailing, and industry. Key issues include derivation and computation of attributes of images and objects that provide useful query functionality, retrieval methods based on similarity as opposed to exact match, query by image example or user drawn image, the user interfaces, query refinement and navigation, high dimensional database indexing, and automatic and semi-automatic database population. We currently have a prototype system written in X/Motif and C running on an RS/6000 that allows a variety of queries, and a test database of over 1000 images and 1000 objects populated from commercially available photo clip art images. In this paper we present the main algorithms for color texture, shape and sketch query that we use, show example query results, and discuss future directions.

Surveillance of transmitted HIV drug resistance in antiretroviral-naive patients aged less than 25 years, in Bangkok, Thailand.

PubMed

Sungkanuparph, Somnuek; Pasomsub, Ekawat; Chantratita, Wasun

2014-01-01

Emergence of transmitted HIV drug resistance (TDR) is a concern after global scale-up of antiretroviral therapy (ART). World Health Organization had developed threshold survey method for surveillance of TDR in resource-limited countries. ART in Thailand has been scaling up for >10 years. To evaluate the current TDR in Thailand, a cross-sectional study was conducted among antiretroviral-naive HIV-infected patients aged <25 years who newly visited infectious disease clinic in a university hospital, in 2011. HIV genotypic-resistance test was performed. World Health Organization 2009 surveillance drug-resistance mutations were used to define TDR. Of 50 patients, the prevalence of TDR was 4%. Of 2 patients with TDR, 1 had K103N and the other had Y181C mutations. Transmitted HIV drug resistance is emerging in Thailand after a decade of rapid scale-up of ART. Interventions to prevent TDR at the population level are essentially needed in Thailand. Surveillance for TDR in Thailand has to be regularly performed.

Nutrition and parturition date effects on elk: potential implications for research and management.

Treesearch

John G. Cook; Bruce K. Johnson; Rachel C. Cook; Robert A. Riggs; Tim DelCurto; Larry D. Bryant; Larry L. Irwin

2004-01-01

Understanding and managing those mechanisms that affect population dynamics comprise, perhaps, the most fundamental aspect of wildlife management (Caughley 1977). Biologists generally categorize these mechanisms as either top-down (predator-driven) or bottom-up (habitat- or animal-density driven). Bottom-up influences involve imbalances between increasing animal...

Bottom Up Succession Planning Works Better.

ERIC Educational Resources Information Center

Stevens, Paul

The majority of current succession planning practices reflect the viewpoint of only a linear career direction for ambitious people. They are based on the premise that competent people have and want only one career direction--an upwardly mobile one. In today's work force, however, a "bottom-up" process works better in succession planning. This…

The landscape of fear: The missing link to understand top-down and bottom-up controls of prey abundance?

USDA-ARS?s Scientific Manuscript database

Identifying factors that may be responsible for affecting and possibly regulating the size of animal populations is a cornerstone in understanding population ecology. The main factors that are thought to influence population size are either resources (bottom-up), predation, (top-down), or interspec...

The Girlfriends Project: Evaluating a Promising Community-Based Intervention from a Bottom-Up Perspective

ERIC Educational Resources Information Center

Hawk, Mary

2015-01-01

Randomized controlled trials are the gold standard in research but may not fully explain or predict outcome variations in community-based interventions. Demonstrating efficacy of externally driven programs in well-controlled environments may not translate to community-based implementation where resources and priorities vary. A bottom-up evaluation…

Challenges in Engaging Communities in Bottom-Up Literacies for Democratic Citizenship

ERIC Educational Resources Information Center

Torres, Myriam N.

2010-01-01

The purpose of this article is to examine the authors' experiences while trying to enter and engage local communities in bottom-up literacies through participatory action research (PAR) toward the community's own collective self-development. In trying to enter five different communities, I have found several challenges and roadblocks such as…

Comparing Top-Down with Bottom-Up Approaches: Teaching Data Modeling

ERIC Educational Resources Information Center

Kung, Hsiang-Jui; Kung, LeeAnn; Gardiner, Adrian

2013-01-01

Conceptual database design is a difficult task for novice database designers, such as students, and is also therefore particularly challenging for database educators to teach. In the teaching of database design, two general approaches are frequently emphasized: top-down and bottom-up. In this paper, we present an empirical comparison of students'…

Bottom-Up Analysis of Single-Case Research Designs

ERIC Educational Resources Information Center

Parker, Richard I.; Vannest, Kimberly J.

2012-01-01

This paper defines and promotes the qualities of a "bottom-up" approach to single-case research (SCR) data analysis. Although "top-down" models, for example, multi-level or hierarchical linear models, are gaining momentum and have much to offer, interventionists should be cautious about analyses that are not easily understood, are not governed by…

An integrated top-down and bottom-up proteomic approach to characterize the antigen-binding fragment of antibodies.

PubMed

Dekker, Lennard; Wu, Si; Vanduijn, Martijn; Tolić, Nikolai; Stingl, Christoph; Zhao, Rui; Luider, Theo; Paša-Tolić, Ljiljana

2014-05-01

We have previously shown that different individuals exposed to the same antigen produce antibodies with identical mutations in their complementarity determining regions (CDR), suggesting that CDR tryptic peptides can serve as biomarkers for disease diagnosis and prognosis. Complete Fabs derived from disease specific antibodies have even higher potential; they could potentially be used for disease treatment and are required to identify the antigens toward which the antibodies are directed. However, complete Fab sequence characterization via LC-MS analysis of tryptic peptides (i.e. bottom-up) has proven to be impractical for mixtures of antibodies. To tackle this challenge, we have developed an integrated bottom-up and top-down MS approach, employing 2D chromatography coupled with Fourier transform mass spectrometry (FTMS), and applied this approach for full characterization of the variable parts of two pharmaceutical monoclonal antibodies with sensitivity comparable to the bottom-up standard. These efforts represent an essential step toward the identification of disease specific antibodies in patient samples with potentially significant clinical impact. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Component processes in voluntary task switching.

PubMed

Demanet, Jelle; Liefooghe, Baptist

2014-05-01

The present study investigated the involvement of bottom-up and top-down control in task-switching situations in which tasks are selected on a voluntary basis. We tested for indices of both types of control in the reduction in switch cost that is observed when more time is available before executing a task. Participants had to indicate their task choice overtly prior to the actual task execution, and two time intervals were manipulated: the interval between the task-execution response of the previous trial and task-indication response of the current trial and the interval between task-indication response and task-execution response of a particular trial. In Experiment 1, the length of these intervals was manipulated orthogonally, and indices for top-down and bottom-up control were observed. Concerned with the validity of these results, Experiments 2-3 additionally discouraged participants from preparing the upcoming task before their task-indication response. Indices for bottom-up control remained, but not for top-down control. The characteristics of top-down and bottom-up control in voluntary task switching and task switching in general are discussed.

An integrated top-down and bottom-up proteomic approach to characterize the antigen binding fragment of antibodies

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

Dekker, Leendert J.; Wu, Si; vanDuijn, Martijn M.

2014-05-31

We have previously shown that different individuals exposed to the same antigen produce antibodies with identical mutations in their complementarity determining regions (CDR), suggesting that CDR tryptic peptides can serve as biomarkers for disease diagnosis and prognosis. Complete Fabs derived from disease specific antibodies have even higher potential; they could potentially be used for disease treatment and are required to identify the antigens towards which the antibodies are directed. However, complete Fab sequence characterization via LC-MS analysis of tryptic peptides (i.e. bottom-up) has proven to be impractical for mixtures of antibodies. To tackle this challenge, we have developed an integratedmore » bottom-up and top-down MS approach, employing 2D chromatography coupled with Fourier transform mass spectrometry (FTMS), and applied this approach for full characterization of the variable parts of two pharmaceutical monoclonal antibodies with sensitivity comparable to the bottom-up standard. These efforts represent an essential step towards the identification of disease specific antibodies in patient samples with potentially significant clinical impact.« less

Loss to follow-up before and after initiation of antiretroviral therapy in HIV facilities in Lilongwe, Malawi

PubMed Central

Tweya, Hannock; Oboho, Ikwo Kitefre; Gugsa, Salem T.; Phiri, Sam; Rambiki, Ethel; Banda, Rebecca; Mwafilaso, Johnbosco; Munthali, Chimango; Gupta, Sundeep; Bateganya, Moses; Maida, Alice

2018-01-01

Introduction Although several studies have explored factors associated with loss to follow-up (LTFU) from HIV care, there remains a gap in understanding how these factors vary by setting, volume of patient and patients’ demographic and clinical characteristics. We determined rates and factors associated with LTFU in HIV care Lilongwe, Malawi. Methods We conducted a retrospective cohort study of HIV-infected individuals aged 15 years or older at the time of registration for HIV care in 12 ART facilities, between April 2012 and March 2013. HIV-positive individuals who had not started ART (pre-ART patients) were clinically assessed to determine ART eligibility at registration and during clinic follow-up visits. ART-eligible patients were initiated on triple antiretroviral combination. Study data were abstracted from patients’ cards, facility ART registers or electronic medical record system from the date of registration for HIV care to a maximum follow-up period of 24 months. Descriptive statistics were undertaken to summarize characteristics of the study patients. Separate univariable and multivariable poisson regression models were used to explore factors associated with LTFU in pre-ART and ART care. Results A total of 10,812 HIV-infected individuals registered for HIV care. Of these patients, 1,907 (18%) and 8,905 (82%) enrolled in pre-ART and ART care, respectively. Of the 1,907 pre-ART patients, 490 (26%) subsequently initiated ART and were included in both the pre-ART and ART analyses. The LTFU rates among patients in pre-ART and ART care were 48 and 26 per 100 person-years, respectively. Of the 9,105 ART patients with reasons for starting ART, 2,451 (27%) were initiated on ART because of pregnancy or breastfeeding (Option B+) status. Multivariable analysis showed that being ≥35 years and female were associated with decreased risk of LTFU in the pre-ART and ART phases of HIV care. However, being in WHO clinical stage 3 (adjusted risk ratio (aRR) 1.35, 95% confidence interval (CI): 1.20–1.51) and stage 4 (aRR 1.87, 95% CI: 1.62–2.18), body mass index ≤ 18.4 (aRR 1.24, 95% CI: 1.11–1.39) at ART initiation, poor adherence to clinic appointments (aRR 4.55, 95% CI: 4.16–4.97) and receiving HIV care in rural facilities (aRR 2.32, 95% CI: 1.94–2.87) were associated with increased risk of LTFU among ART patients. Being re-initiated on ART once (aRR 0.20, 95% CI: 0.17–0.22), more than once (aRR 0.06, 95% CI: 0.05–0.07), and being enrolled at a low-volume facility (aRR 0.25, 95% CI: 0.20–0.30) were associated with decreased risk of LTFU from ART care. Conclusion A sizeable proportion of ART LTFU occurred among women enrolled during pregnancy or breast-feeding. Non- compliance to clinic and receiving ART in a rural facility or high-volume facility were associated with increased risk of LTFU from ART care. Developing effective interventions that target high-risk subgroups and contexts may help reduce LTFU from HIV care. PMID:29373574

Physical stress modifies top-down and bottom-up forcing on plant growth and reproduction in a coastal ecosystem.

PubMed

Daleo, Pedro; Alberti, Juan; Bruschetti, Carlos Martin; Pascual, Jesos; Iribarne, Oscar; Silliman, Brian R

2015-08-01

Bottom-up and top-down effects act together to exert strong control over plant growth and reproduction, but how physical stress modifies those interactive forces remains unclear. Even though empirical evidence is scarce, theory predicts that the importance of both top-down- and bottom-up forces may decrease as physical stress increases. Here, we experimentally evaluate in the field the separate and interactive effect of salinity, nutrient availability, and crab herbivory on plant above- and belowground biomass, as well as on sexual and clonal reproduction in the salt marsh plant Spartina densiflora. Results show that the outcome of the interaction between nutrient availability and herbivory is highly context dependent, not only varying with the abiotic context (i.e., with or without increased salinity stress), but also with the dependent variable considered. Contrary to theoretical predictions, our results show that, consistently across different measured variables, salinity stress did not cancel bottom-up (i.e., nutrients) or top-down (i.e., consumers) control, but has additive effects. Our results support emerging theory by highlighting that, under many conditions, physical stress can act additively with, or even stimulate, consumer control, especially in cases where the physical stress is only experienced by basal levels of the trophic chain. Abiotic stress, as well as bottom-up and top-down factors, can affect salt marsh structure and function not only by affecting biomass production but also by having other indirect effects, such as changing patterns in plant biomass allocation and reproduction.

A critical role of temporoparietal junction in the integration of top-down and bottom-up attentional control

PubMed Central

Wu, Qiong; Chang, Chi-Fu; Xi, Sisi; Huang, I-Wen; Liu, Zuxiang; Juan, Chi-Hung; Wu, Yanhong; Fan, Jin

2015-01-01

Information processing can be biased toward behaviorally relevant and salient stimuli by top-down (goal-directed) and bottom-up (stimulus-driven) attentional control processes. However, the neural basis underlying the integration of these processes is not well understood. We employed functional magnetic resonance imaging and transcranial direct-current stimulation (tDCS) in humans to examine the brain mechanisms underlying the interaction between these two processes. We manipulated the cognitive load involved in top-down processing and stimulus surprise involved in bottom-up processing in a factorial design by combining a majority function task and an oddball paradigm. We found that high cognitive load and high surprise level were associated with prolonged reaction time compared to low cognitive load and low surprise level, with a synergistic interaction effect which was accompanied by a greater deactivation of bilateral temporoparietal junction (TPJ). In addition, the TPJ displayed negative functional connectivity with right middle occipital gyrus involved in bottom-up processing (modulated by the interaction effect) and the right frontal eye field (FEF) involved in top-down control. The enhanced negative functional connectivity between the TPJ and right FEF was accompanied by a larger behavioral interaction effect across subjects. Application of cathodal tDCS over the right TPJ eliminated the interaction effect. These results suggest that the TPJ plays a critical role in processing bottom-up information for top-down control of attention. PMID:26308973

Assessment of discrepancies between bottom-up and regional emission inventories in Norwegian urban areas

NASA Astrophysics Data System (ADS)

López-Aparicio, Susana; Guevara, Marc; Thunis, Philippe; Cuvelier, Kees; Tarrasón, Leonor

2017-04-01

This study shows the capabilities of a benchmarking system to identify inconsistencies in emission inventories, and to evaluate the reason behind discrepancies as a mean to improve both bottom-up and downscaled emission inventories. Fine scale bottom-up emission inventories for seven urban areas in Norway are compared with three regional emission inventories, EC4MACS, TNO_MACC-II and TNO_MACC-III, downscaled to the same areas. The comparison shows discrepancies in nitrogen oxides (NOx) and particulate matter (PM2.5 and PM10) when evaluating both total and sectorial emissions. The three regional emission inventories underestimate NOx and PM10 traffic emissions by approximately 20-80% and 50-90%, respectively. The main reasons for the underestimation of PM10 emissions from traffic in the regional inventories are related to non-exhaust emissions due to resuspension, which are included in the bottom-up emission inventories but are missing in the official national emissions, and therefore in the downscaled regional inventories. The benchmarking indicates that the most probable reason behind the underestimation of NOx traffic emissions by the regional inventories is the activity data. The fine scale NOx traffic emissions from bottom-up inventories are based on the actual traffic volume at the road link and are much higher than the NOx emissions downscaled from national estimates based on fuel sales and based on population for the urban areas. We have identified important discrepancies in PM2.5 emissions from wood burning for residential heating among all the inventories. These discrepancies are associated with the assumptions made for the allocation of emissions. In the EC4MACs inventory, such assumptions imply high underestimation of PM2.5 emissions from the residential combustion sector in urban areas, which ranges from 40 to 90% compared with the bottom-up inventories. The study shows that in three of the seven Norwegian cities there is need for further improvement of the emission inventories.

Abundant Lysine Methylation and N-Terminal Acetylation in Sulfolobus islandicus Revealed by Bottom-Up and Top-Down Proteomics*

PubMed Central

Vorontsov, Egor A.; Rensen, Elena; Prangishvili, David; Krupovic, Mart; Chamot-Rooke, Julia

2016-01-01

Protein post-translational methylation has been reported to occur in archaea, including members of the genus Sulfolobus, but has never been characterized on a proteome-wide scale. Among important Sulfolobus proteins carrying such modification are the chromatin proteins that have been described to be methylated on lysine side chains, resembling eukaryotic histones in that aspect. To get more insight into the extent of this modification and its dynamics during the different growth steps of the thermoacidophylic archaeon S. islandicus LAL14/1, we performed a global and deep proteomic analysis using a combination of high-throughput bottom-up and top-down approaches on a single high-resolution mass spectrometer. 1,931 methylation sites on 751 proteins were found by the bottom-up analysis, with methylation sites on 526 proteins monitored throughout three cell culture growth stages: early-exponential, mid-exponential, and stationary. The top-down analysis revealed 3,978 proteoforms arising from 681 proteins, including 292 methylated proteoforms, 85 of which were comprehensively characterized. Methylated proteoforms of the five chromatin proteins (Alba1, Alba2, Cren7, Sul7d1, Sul7d2) were fully characterized by a combination of bottom-up and top-down data. The top-down analysis also revealed an increase of methylation during cell growth for two chromatin proteins, which had not been evidenced by bottom-up. These results shed new light on the ubiquitous lysine methylation throughout the S. islandicus proteome. Furthermore, we found that S. islandicus proteins are frequently acetylated at the N terminus, following the removal of the N-terminal methionine. This study highlights the great value of combining bottom-up and top-down proteomics for obtaining an unprecedented level of accuracy in detecting differentially modified intact proteoforms. The data have been deposited to the ProteomeXchange with identifiers PXD003074 and PXD004179. PMID:27555370

HIV Treatment as Prevention: Modelling the Cost of Antiretroviral Treatment—State of the Art and Future Directions

PubMed Central

Meyer-Rath, Gesine; Over, Mead

2012-01-01

Policy discussions about the feasibility of massively scaling up antiretroviral therapy (ART) to reduce HIV transmission and incidence hinge on accurately projecting the cost of such scale-up in comparison to the benefits from reduced HIV incidence and mortality. We review the available literature on modelled estimates of the cost of providing ART to different populations around the world, and suggest alternative methods of characterising cost when modelling several decades into the future. In past economic analyses of ART provision, costs were often assumed to vary by disease stage and treatment regimen, but for treatment as prevention, in particular, most analyses assume a uniform cost per patient. This approach disregards variables that can affect unit cost, such as differences in factor prices (i.e., the prices of supplies and services) and the scale and scope of operations (i.e., the sizes and types of facilities providing ART). We discuss several of these variables, and then present a worked example of a flexible cost function used to determine the effect of scale on the cost of a proposed scale-up of treatment as prevention in South Africa. Adjusting previously estimated costs of universal testing and treatment in South Africa for diseconomies of small scale, i.e., more patients being treated in smaller facilities, adds 42% to the expected future cost of the intervention. PMID:22802731

Our Students Need More Practice in Actual Thinking

ERIC Educational Resources Information Center

Jenkins, Rob

2009-01-01

The author is dismayed to find that the liberal-arts curriculum--the so-called "core"--is under attack, especially at two-year schools. It "is" under attack, from legislators with no understanding of the aims of higher education; from administrators focused short-sightedly on the bottom line; from chamber-of-commerce types who read "college" as…

"O Bottom, Thou Art Translated": Directing a Bilingual Dream in the Marshall Islands

ERIC Educational Resources Information Center

Garrod, Andrew

2005-01-01

A unique production of Shakespeare's "A Midsummer Night's Dream" was staged in early 2004 by students of the Marshall Islands High School, Majuro, in the Central Pacific. The play's director, Andrew Garrod, describes the rehearsal process and performance of the play, in which the school students were supported by undergraduates from the…

Social Comparison and Peer Effects at an Elite College. Discussion Paper.

ERIC Educational Resources Information Center

Goethals, George R.

A study was conducted to see whether peer effects could be observed among 102 undergraduates at Williams College, an elite four-year liberal arts school. The study explored whether students in the bottom third of their class, with average Scholastic Assessment Test (SAT) scores of about 1300, would perform better in writing about newspaper…

Art across the Curriculum: Ellipse Clips

ERIC Educational Resources Information Center

Sartorius, Tara Cady

2011-01-01

This article discusses Al Souza's "Orlando City Maps," which was created not by adding colored ink to paper, but by cutting the printed paper away. Seven layers of pages are stacked upon one another and, except for the intact bottom layer, oval-shaped holes are cut through each page to reveal the layers below. When designing "Orlando City Maps,"…

Retention and Risk Factors for Attrition in a Large Public Health ART Program in Myanmar: A Retrospective Cohort Analysis

PubMed Central

Thida, Aye; Tun, Sai Thein Than; Zaw, Sai Ko Ko; Lover, Andrew A.; Cavailler, Philippe; Chunn, Jennifer; Aye, Mar Mar; Par, Par; Naing, Kyaw Win; Zan, Kaung Nyunt; Shwe, Myint; Kyaw, Thar Tun; Waing, Zaw Htoon; Clevenbergh, Philippe

2014-01-01

Background The outcomes from an antiretroviral treatment (ART) program within the public sector in Myanmar have not been reported. This study documents retention and the risk factors for attrition in a large ART public health program in Myanmar. Methods A retrospective analysis of a cohort of adult patients enrolled in the Integrated HIV Care (IHC) Program between June 2005 and October 2011 and followed up until April 2012 is presented. The primary outcome was attrition (death or loss-follow up); a total of 10,223 patients were included in the 5-year cumulative survival analysis. Overall 5,718 patients were analyzed for the risk factors for attrition using both logistic regression and flexible parametric survival models. Result The mean age was 36 years, 61% of patients were male, and the median follow up was 13.7 months. Overall 8,564 (84%) patients were retained in ART program: 750 (7%) were lost to follow-up and 909 (9%) died. During the 3 years follow-up, 1,542 attritions occurred over 17,524 person years at risk, giving an incidence density of 8.8% per year. The retention rates of participants at 12, 24, 36, 48 and 60 months were 86, 82, 80, 77 and 74% respectively. In multivariate analysis, being male, having high WHO staging, a low CD4 count, being anaemic or having low BMI at baseline were independent risk factors for attrition; tuberculosis (TB) treatment at ART initiation, a prior ART course before program enrollment and literacy were predictors for retention in the program. Conclusion High retention rate of IHC program was documented within the public sector in Myanmar. Early diagnosis of HIV, nutritional support, proper investigation and treatment for patients with low CD4 counts and for those presenting with anaemia are crucial issues towards improvement of HIV program outcomes in resource-limited settings. PMID:25268903

High-strength magnetically switchable plasmonic nanorods assembled from a binary nanocrystal mixture

DOE PAGES

Zhang, Mingliang; Magagnosc, Daniel J.; Liberal, Iñigo; ...

2016-11-07

Next-generation ‘smart’ nanoparticle systems should be precisely engineered in size, shape and composition to introduce multiple functionalities, unattainable from a single material. Bottom-up chemical methods are prized for the synthesis of crystalline nanoparticles, that is, nanocrystals, with size- and shape-dependent physical properties, but they are less successful in achieving multifunctionality. Top-down lithographic methods can produce multifunctional nanoparticles with precise size and shape control, yet this becomes increasingly difficult at sizes of ~10 nm. In this paper, we report the fabrication of multifunctional, smart nanoparticle systems by combining top-down fabrication and bottom-up self-assembly methods. Particularly, we template nanorods from a mixturemore » of superparamagnetic Zn 0.2Fe 2.8O 4 and plasmonic Au nanocrystals. The superparamagnetism of Zn 0.2Fe 2.8O 4 prevents these nanorods from spontaneous magnetic-dipole-induced aggregation, while their magnetic anisotropy makes them responsive to an external field. Ligand exchange drives Au nanocrystal fusion and forms a porous network, imparting the nanorods with high mechanical strength and polarization-dependent infrared surface plasmon resonances. Finally, the combined superparamagnetic and plasmonic functions enable switching of the infrared transmission of a hybrid nanorod suspension using an external magnetic field.« less

A 'movement for improvement'? A qualitative study of the adoption of social movement strategies in the implementation of a quality improvement campaign.

PubMed

Waring, Justin; Crompton, Amanda

2017-09-01

Given the difficulties of implementing 'top-down' quality improvements, health service leaders have turned to methods that empower clinicians to co-produce 'bottom-up' improvements. This has involved the adoption of strategies and activities associated with social movements, with clinicians encouraged to participate in collective action towards the shared goal of improvement. This paper examines the adoption of social movement methods by hospital managers as a strategy for implementing a quality improvement 'campaign'. Our case study suggests that, despite the claim of empowering clinicians to develop 'bottom-up' improvements, the use of social movement methods can be more narrowly concerned with engaging clinicians in pre-determined programmes of 'top-down' change. It finds a prominent role for 'hybrid' clinical leaders and other staff representatives in the mobilisation of the campaign, especially for enrolling clinicians in change activities. The work of these 'hybrids' suggests some degree of creative mediation between clinical and managerial interests, but more often alignment with the aspirations of management. The study raises questions about the translation of social movement's theories as a strategy for managing change and re-inventing professionalism. © 2017 The Authors. Sociology of Health & Illness published by John Wiley & Sons Ltd on behalf of Foundation for SHIL.

Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of organochlorine pesticides and polychlorinated biphenyls in bottom sediment by dual capillary-column gas chromatography with electron-capture detection

USGS Publications Warehouse

Foreman, William T.; Connor, Brooke F.; Furlong, Edward T.; Vaught, Deborah G.; Merten, Leslie M.

1995-01-01

A method for the determination of 30 individual organochlorine pesticides, total toxaphene, and total polychlorinated biphenyls (PCBs) in bottom sediment is described. The method isolates the pesticides and PCBs by solvent extraction with dichlorobenzene, removes inorganic sulfur, large naturally occurring molecules, and other unwanted interferences by gel permeation chromatography, and further cleans up and class fractionates the extract using adsorption chromatography. The com- pounds then are instrumentally determined using dual capillary-column gas chromatography with electron-capture detection. Reporting limits range from 1 to 5 micrograms per kilogram for 30 individual pesticides, 50 micrograms per kilogram for total PCBs, and 200 micrograms per kilogram for total toxaphene. The method also is designed to allow the simultaneous isolation of 79 other semivolatile organic compounds from the sediment, which are separately quantified using gas chromatography with mass spectrometric detection. The method was developed in support of the U.S. Geological Survey's National Water-Quality Assessment program.

Long terms trends in CD4+ cell counts, CD8+ cell counts, and the CD4+ : CD8+ ratio

PubMed Central

Hughes, Rachael A.; May, Margaret T.; Tilling, Kate; Taylor, Ninon; Wittkop, Linda; Reiss, Peter; Gill, John; Schommers, Philipp; Costagliola, Dominique; Guest, Jodie L.; Lima, Viviane D.; d’Arminio Monforte, Antonella; Smith, Colette; Cavassini, Matthias; Saag, Michael; Castilho, Jessica L.; Sterne, Jonathan A.C.

2018-01-01

Objective: Model trajectories of CD4+ and CD8+ cell counts after starting combination antiretroviral therapy (ART) and use the model to predict trends in these counts and the CD4+ : CD8+ ratio. Design: Cohort study of antiretroviral-naïve HIV-positive adults who started ART after 1997 (ART Cohort Collaboration) with more than 6 months of follow-up data. Methods: We jointly estimated CD4+ and CD8+ cell count trends and their correlation using a bivariate random effects model, with linear splines describing their population trends, and predicted the CD4+ : CD8+ ratio trend from this model. We assessed whether CD4+ and CD8+ cell count trends and the CD4+ : CD8+ ratio trend varied according to CD4+ cell count at start of ART (baseline), and, whether these trends differed in patients with and without virological failure more than 6 months after starting ART. Results: A total of 39 979 patients were included (median follow-up was 53 months). Among patients with baseline CD4+ cell count at least 50 cells/μl, predicted mean CD8+ cell counts continued to decrease between 3 and 15 years post-ART, partly driving increases in the predicted mean CD4+ : CD8+ ratio. During 15 years of follow-up, normalization of the predicted mean CD4+ : CD8+ ratio (to >1) was only observed among patients with baseline CD4+ cell count at least 200 cells/μl. A higher baseline CD4+ cell count predicted a shorter time to normalization. Conclusion: Declines in CD8+ cell count and increases in CD4+ : CD8+ ratio occurred up to 15 years after starting ART. The likelihood of normalization of the CD4+ : CD8+ ratio is strongly related to baseline CD4+ cell count. PMID:29851663

Antiretroviral treatment interruption and loss to follow-up in two HIV cohorts in Australia and Asia: implications for 'test and treat' prevention strategy.

PubMed

Guy, Rebecca; Wand, Handan; McManus, Hamish; Vonthanak, Saphonn; Woolley, Ian; Honda, Miwako; Read, Tim; Sirisanthana, Thira; Zhou, Julian; Carr, Andrew

2013-12-01

Both antiretroviral treatment interruption (TI) and cessation have been strongly discouraged since 2006. We describe the incidence, duration, and risk factors for TI and loss-to-follow-up (LTFU) rates across 13 countries. All 4689 adults (76% men) in two large HIV cohorts in Australia and Asia commencing combination antiretroviral therapy (ART) to March 2010 were included. TI was defined by ART cessation >30 days, then recommencement, and loss to follow-up (LTFU) by no visit since 31 March 2009 and no record of death. Survival analysis and Poisson regression methods were used. With median follow-up of 4.4 years [interquartile range (IQR):2.1-6.5], TI incidence was 6.7 per 100 person years (PY) (95% CI:6.1-7.3) pre-2006, falling to 2.0 (95% CI:1.7-2.2) from 2006 (p<0.01). LTFU incidence was 3.5 per 100 PY (95% CI:3.1-3.9) pre-2006, and 4.1 (95% CI:3.5-4.9) from 2006 (p=0.22). TIs accounted for 6.4% of potential time on ART pre-2006 and 1.2% from 2006 (p<0.01), and LTFU 4.7% of potential time on ART pre-2006 and 6.6% from 2006 (p<0.01). Median TI duration was 163 (IQR: 75-391) days pre-2006 and 118 (IQR: 67-270) days from 2006 (p<0.01). Independent risk factors for the first TI were: Australia HIV Observational Database participation; ART initiation pre-2006; ART regimens including stavudine and didanosine; three nucleoside analogue reverse transcriptase inhibitors; ≥7 pills per day; and ART with food restrictions (fasting or with food). In conclusion, since 2006, 7.8% of patients had significant time off treatment, which has the potential to compromise any 'test and treat' policy as during the interruption viral load will rebound and increase the risk of transmission.

Long-term CO2 fertilization increases vegetation productivity and has little effect on hydrological partitioning in tropical rainforests

NASA Astrophysics Data System (ADS)

Yang, Yuting; Donohue, Randall J.; McVicar, Tim R.; Roderick, Michael L.; Beck, Hylke E.

2016-08-01

Understanding how tropical rainforests respond to elevated atmospheric CO2 concentration (eCO2) is essential for predicting Earth's carbon, water, and energy budgets under future climate change. Here we use long-term (1982-2010) precipitation (P) and runoff (Q) measurements to infer runoff coefficient (Q/P) and evapotranspiration (E) trends across 18 unimpaired tropical rainforest catchments. We complement that analysis by using satellite observations coupled with ecosystem process modeling (using both "top-down" and "bottom-up" perspectives) to examine trends in carbon uptake and relate that to the observed changes in Q/P and E. Our results show there have been only minor changes in the satellite-observed canopy leaf area over 1982-2010, suggesting that eCO2 has not increased vegetation leaf area in tropical rainforests and therefore any plant response to eCO2 occurs at the leaf level. Meanwhile, observed Q/P and E also remained relatively constant in the 18 catchments, implying an unchanged hydrological partitioning and thus approximately conserved transpiration under eCO2. For the same period, using a top-down model based on gas exchange theory, we predict increases in plant assimilation (A) and light use efficiency (ɛ) at the leaf level under eCO2, the magnitude of which is essentially that of eCO2 (i.e., 12% over 1982-2010). Simulations from 10 state-of-the-art bottom-up ecosystem models over the same catchments also show that the direct effect of eCO2 is to mostly increase A and ɛ with little impact on E. Our findings add to the current limited pool of knowledge regarding the long-term eCO2 impacts in tropical rainforests.

Art as a Means of Accessing Ourselves. Using Art in Psychotherapy.

PubMed

d'Errico, Immacolata

2017-09-01

Using art in psychotherapy could become an interesting instrument for the cure and the prevention of psychological and psychiatric problems. This belongs to that trend that sees the mediation of art as having big potential to go beyond the spoken word. Everybody knows that our emotions, thoughts, feelings, and so on, are living in the body and speaking through the body, in fact the symbolic dimension (art, music, dance, painting and so on) reconfigures the experience of living. In this form of therapy we use Art as a means of accessing ourselves and opening ourselves up to the world. The forms of artistic mediation that we mainly describe in the paper are the basic elements of tango and performative theatrical technique (Theatre of the Oppressed and Physical Theatre). In the final part of this paper a series of images illustrate specific cases in which the method and its outcomes are described.

Bottom-Up and Top-Down Solid-State NMR Approaches for Bacterial Biofilm Matrix Composition

PubMed Central

Cegelski, Lynette

2015-01-01

The genomics and proteomics revolutions have been enormously successful in providing crucial “parts lists” for biological systems. Yet, formidable challenges exist in generating complete descriptions of how the parts function and assemble into macromolecular complexes and whole-cell assemblies. Bacterial biofilms are complex multicellular bacterial communities protected by a slime-like extracellular matrix that confers protection to environmental stress and enhances resistance to antibiotics and host defenses. As a non-crystalline, insoluble, heterogeneous assembly, the biofilm extracellular matrix poses a challenge to compositional analysis by conventional methods. In this Perspective, bottom-up and top-down solid-state NMR approaches are described for defining chemical composition in complex macrosystems. The “sum-of-theparts” bottom-up approach was introduced to examine the amyloid-integrated biofilms formed by E. coli and permitted the first determination of the composition of the intact extracellular matrix from a bacterial biofilm. An alternative top-down approach was developed to define composition in V. cholerae biofilms and relied on an extensive panel of NMR measurements to tease out specific carbon pools from a single sample of the intact extracellular matrix. These two approaches are widely applicable to other heterogeneous assemblies. For bacterial biofilms, quantitative parameters of matrix composition are needed to understand how biofilms are assembled, to improve the development of biofilm inhibitors, and to dissect inhibitor modes of action. Solid-state NMR approaches will also be invaluable in obtaining parameters of matrix architecture. PMID:25797008

Bottom-up and top-down solid-state NMR approaches for bacterial biofilm matrix composition.

PubMed

Cegelski, Lynette

2015-04-01

The genomics and proteomics revolutions have been enormously successful in providing crucial "parts lists" for biological systems. Yet, formidable challenges exist in generating complete descriptions of how the parts function and assemble into macromolecular complexes and whole-cell assemblies. Bacterial biofilms are complex multicellular bacterial communities protected by a slime-like extracellular matrix that confers protection to environmental stress and enhances resistance to antibiotics and host defenses. As a non-crystalline, insoluble, heterogeneous assembly, the biofilm extracellular matrix poses a challenge to compositional analysis by conventional methods. In this perspective, bottom-up and top-down solid-state NMR approaches are described for defining chemical composition in complex macrosystems. The "sum-of-the-parts" bottom-up approach was introduced to examine the amyloid-integrated biofilms formed by Escherichia coli and permitted the first determination of the composition of the intact extracellular matrix from a bacterial biofilm. An alternative top-down approach was developed to define composition in Vibrio cholerae biofilms and relied on an extensive panel of NMR measurements to tease out specific carbon pools from a single sample of the intact extracellular matrix. These two approaches are widely applicable to other heterogeneous assemblies. For bacterial biofilms, quantitative parameters of matrix composition are needed to understand how biofilms are assembled, to improve the development of biofilm inhibitors, and to dissect inhibitor modes of action. Solid-state NMR approaches will also be invaluable in obtaining parameters of matrix architecture. Copyright © 2015 Elsevier Inc. All rights reserved.

Sediment unmixing using detrital geochronology

NASA Astrophysics Data System (ADS)

Sharman, Glenn R.; Johnstone, Samuel A.

2017-11-01

Sediment mixing within sediment routing systems can exert a strong influence on the preservation of provenance signals that yield insight into the effect of environmental forcing (e.g., tectonism, climate) on the Earth's surface. Here, we discuss two approaches to unmixing detrital geochronologic data in an effort to characterize complex changes in the sedimentary record. First, we summarize 'top-down' mixing, which has been successfully employed in the past to characterize the different fractions of prescribed source distributions ('parents') that characterize a derived sample or set of samples ('daughters'). Second, we propose the use of 'bottom-up' methods, previously used primarily for grain size distributions, to model parent distributions and the abundances of these parents within a set of daughters. We demonstrate the utility of both top-down and bottom-up approaches to unmixing detrital geochronologic data within a well-constrained sediment routing system in central California. Use of a variety of goodness-of-fit metrics in top-down modeling reveals the importance of considering the range of allowable that is well mixed over any single best-fit mixture calculation. Bottom-up modeling of 12 daughter samples from beaches and submarine canyons yields modeled parent distributions that are remarkably similar to those expected from the geologic context of the sediment-routing system. In general, mixture modeling has the potential to supplement more widely applied approaches in comparing detrital geochronologic data by casting differences between samples as differing proportions of geologically meaningful end-member provenance categories.

Altered emotional interference processing in affective and cognitive-control brain circuitry in major depression

PubMed Central

Fales, Christina L.; Barch, Deanna M.; Rundle, Melissa M.; Mintun, Mark A.; Snyder, Abraham Z.; Cohen, Jonathan D.; Mathews, Jose; Sheline, Yvette I.

2008-01-01

Background Major depression is characterized by a negativity bias: an enhanced responsiveness to, and memory for, affectively negative stimuli. However it is not yet clear whether this bias represents (1) impaired top-down cognitive control over affective responses, potentially linked to deficits in dorsolateral prefrontal cortex function; or (2) enhanced bottom-up responses to affectively-laden stimuli that dysregulate cognitive control mechanisms, potentially linked to deficits in amygdala and anterior cingulate function. Methods We used an attentional interference task using emotional distracters to test for top-down versus bottom-up dysfunction in the interaction of cognitive-control circuitry and emotion-processing circuitry. A total of 27 patients with major depression and 24 controls were tested. Event-related functional magnetic resonance imaging was carried out as participants directly attended to, or attempted to ignore, fear-related stimuli. Results Compared to controls, patients with depression showed an enhanced amygdala response to unattended fear-related stimuli (relative to unattended neutral). By contrast, control participants showed increased activity in right dorsolateral prefrontal cortex (Brodmann areas 46/9) when ignoring fear stimuli (relative to neutral), which the patients with depression did not. In addition, the depressed participants failed to show evidence of error-related cognitive adjustments (increased activity in bilateral dorsolateral prefrontal cortex on post-error trials), but the control group did show them. Conclusions These results suggest multiple sources of dysregulation in emotional and cognitive control circuitry in depression, implicating both top-down and bottom-up dysfunction. PMID:17719567

Bottom-up and top-down solid-state NMR approaches for bacterial biofilm matrix composition

NASA Astrophysics Data System (ADS)

Cegelski, Lynette

2015-04-01

The genomics and proteomics revolutions have been enormously successful in providing crucial "parts lists" for biological systems. Yet, formidable challenges exist in generating complete descriptions of how the parts function and assemble into macromolecular complexes and whole-cell assemblies. Bacterial biofilms are complex multicellular bacterial communities protected by a slime-like extracellular matrix that confers protection to environmental stress and enhances resistance to antibiotics and host defenses. As a non-crystalline, insoluble, heterogeneous assembly, the biofilm extracellular matrix poses a challenge to compositional analysis by conventional methods. In this perspective, bottom-up and top-down solid-state NMR approaches are described for defining chemical composition in complex macrosystems. The "sum-of-the-parts" bottom-up approach was introduced to examine the amyloid-integrated biofilms formed by Escherichia coli and permitted the first determination of the composition of the intact extracellular matrix from a bacterial biofilm. An alternative top-down approach was developed to define composition in Vibrio cholerae biofilms and relied on an extensive panel of NMR measurements to tease out specific carbon pools from a single sample of the intact extracellular matrix. These two approaches are widely applicable to other heterogeneous assemblies. For bacterial biofilms, quantitative parameters of matrix composition are needed to understand how biofilms are assembled, to improve the development of biofilm inhibitors, and to dissect inhibitor modes of action. Solid-state NMR approaches will also be invaluable in obtaining parameters of matrix architecture.

Estimating the cost-effectiveness of nutrition supplementation for malnourished, HIV-infected adults starting antiretroviral therapy in a resource-constrained setting

PubMed Central

2014-01-01

Background Low body mass index (BMI) individuals starting antiretroviral therapy (ART) for HIV infection in sub-Saharan Africa have high rates of death and loss to follow-up in the first 6 months of treatment. Nutritional supplementation may improve health outcomes in this population, but the anticipated benefit of any intervention should be commensurate with the cost given resource limitations and the need to expand access to ART in the region. Methods We used Markov models incorporating historical data and program-wide estimates of treatment costs and health benefits from the Zambian national ART program to estimate the improvements in 6-month survival and program retention among malnourished adults necessary for a combined nutrition support and ART treatment program to maintain cost-effectiveness parity with ART treatment alone. Patients were stratified according to World Health Organization criteria for severe (BMI <16.0 kg/m2), moderate (16.00-16.99 kg/m2), and mild (17.00-18.49 kg/m2) malnutrition categories. Results 19,247 patients contributed data between May 2004 and October 2010. Quarterly survival and retention were lowest in the BMI <16.0 kg/m2 category compared to higher BMI levels, and there was less variation in both measures across BMI strata after 180 days. ART treatment was estimated to cost $556 per year and averted 7.3 disability-adjusted life years. To maintain cost-effectiveness parity with ART alone, a supplement needed to cost $10.99 per quarter and confer a 20% reduction in both 6-month mortality and loss to follow-up among BMI <16.0 kg/m2 patients. Among BMI 17.00-18.49 kg/m2 patients, supplement costs accompanying a 20% reduction in mortality and loss to follow-up could not exceed $5.18 per quarter. In sensitivity analyses, the maximum permitted supplement cost increased if the ART program cost rose, and fell if patients classified as lost to follow-up at 6 months subsequently returned to care. Conclusions Low BMI adults starting ART in sub-Saharan Africa are at high risk of early mortality and loss to follow-up. The expense of providing nutrition supplementation would require only modest improvements in survival and program retention to be cost-effective for the most severely malnourished individuals starting ART, but interventions are unlikely to be cost-effective among those in higher BMI strata. PMID:24839400

Studies of Visual Attention in Physics Problem Solving

ERIC Educational Resources Information Center

Madsen, Adrian M.

2013-01-01

The work described here represents an effort to understand and influence visual attention while solving physics problems containing a diagram. Our visual system is guided by two types of processes--top-down and bottom-up. The top-down processes are internal and determined by ones prior knowledge and goals. The bottom-up processes are external and…

Two-dimensional combinatorial screening enables the bottom-up design of a microRNA-10b inhibitor.

PubMed

Velagapudi, Sai Pradeep; Disney, Matthew D

2014-03-21

The RNA motifs that bind guanidinylated kanamycin A (G Kan A) and guanidinylated neomycin B (G Neo B) were identified via two-dimensional combinatorial screening (2DCS). The results of these studies enabled the "bottom-up" design of a small molecule inhibitor of oncogenic microRNA-10b.

Initial Clinician Reports of the Bottom-Up Dissemination of an Evidence-Based Intervention for Early Childhood Trauma

ERIC Educational Resources Information Center

David, Paula; Schiff, Miriam

2018-01-01

Background: Bottom-up dissemination (BUD) of evidence based treatments (EBT), entailing the spread of an intervention through a peer network in a decentralized manner, is an under-reported phenomenon in the professional literature. Objective: This paper presents findings from a study researching the feasibility of BUD of an evidence-based…

Unleashing the Creative Potential of Faculty to Create Blended Learning

ERIC Educational Resources Information Center

Carbonell, Katerina Bohle; Dailey-Hebert, Amber; Gijselaers, Wim

2013-01-01

Bottom-up managed change processes offer the advantage to use the creative power of faculty to design and implement blended learning programs. This article proposes four factors as crucial elements for a successful bottom-up change process: the macro and micro contexts, the project leader and the project members. Interviews were conducted with 5…

Reading Nature from a "Bottom-Up" Perspective

ERIC Educational Resources Information Center

Magntorn, Ola; Hellden, Gustav

2007-01-01

This paper reports on a study of ecology teaching and learning in a Swedish primary school class (age 10-11 yrs). A teaching sequence was designed to help students read nature in a river ecosystem. The teaching sequence had a "bottom up" approach, taking as its starting point a common key organism--the freshwater shrimp. From this…

Teacher-Led Professional Development: A Proposal for a Bottom-up Structure Approach

ERIC Educational Resources Information Center

Macias, Angela

2017-01-01

This article uses current research recommendations for teacher-led professional development as well as qualitative data from a set of grassroots conferences to propose a new model for bottom-up teacher-led professional development. This article argues that by providing a neutral space and recruiting expertise of local experts, a public sphere can…

Pedagogical Perspectives and Practices Reflected in Metaphors of Learning and Digital Learning of ICT Leaders

ERIC Educational Resources Information Center

Blau, Ina; Grinberg, Ronen; Shamir-Inbal, Tamar

2018-01-01

This study examines the meaning attributed to the contribution of technology to pedagogical practices from the perspective of school ICT leaders. While previous studies use metaphors for bottom-up exploration, this study employs an innovative combination of bottom-up and top-down metaphor analysis based on two frameworks: (a) metaphors of general…

Thinking about the Weather: How Display Salience and Knowledge Affect Performance in a Graphic Inference Task

ERIC Educational Resources Information Center

Hegarty, Mary; Canham, Matt S.; Fabrikant, Sara I.

2010-01-01

Three experiments examined how bottom-up and top-down processes interact when people view and make inferences from complex visual displays (weather maps). Bottom-up effects of display design were investigated by manipulating the relative visual salience of task-relevant and task-irrelevant information across different maps. Top-down effects of…

How Adolescents Comprehend Unfamiliar Proverbs: The Role of Top-Down and Bottom-Up Processes.

ERIC Educational Resources Information Center

Nippold, Marilyn A.; Allen, Melissa M.; Kirsch, Dixon I.

2000-01-01

Relationships between word knowledge and proverb comprehension was examined in 150 typically achieving adolescents (ages 12, 15, and 18). Word knowledge was associated with proverb comprehension in all groups, particularly in the case of abstract proverbs. Results support a model of proverb comprehension in adolescents that includes bottom-up in…

Coupling 2D Finite Element Models and Circuit Equations Using a Bottom-Up Methodology

DTIC Science & Technology

2002-11-01

EQUATIONS USING A BOTTOM-UP METHODOLOGY E. G6mezl, J. Roger-Folch2 , A. Gabald6nt and A. Molina’ ’Dpto. de Ingenieria Eldctrica. Universidad Polit...de Ingenieria Elictrica. ETSII. Universidad Politdcnica de Valencia. PO Box 22012, 46071. Valencia, Spain. E-mail: iroger adie.upv.es ABSTRACT The

A balance of bottom-up and top-down in linking climate policies

NASA Astrophysics Data System (ADS)

Green, Jessica F.; Sterner, Thomas; Wagner, Gernot

2014-12-01

Top-down climate negotiations embodied by the Kyoto Protocol have all but stalled, chiefly because of disagreements over targets and objections to financial transfers. To avoid those problems, many have shifted their focus to linkage of bottom-up climate policies such as regional carbon markets. This approach is appealing, but we identify four obstacles to successful linkage: different levels of ambition; competing domestic policy objectives; objections to financial transfers; and the difficulty of close regulatory coordination. Even with a more decentralized approach, overcoming the 'global warming gridlock' of the intergovernmental negotiations will require close international coordination. We demonstrate how a balance of bottom-up and top-down elements can create a path toward an effective global climate architecture.

Frost Susceptibility of Soil, Review of Index Tests,

DTIC Science & Technology

1981-12-01

contained in the CAA ( 1948 ) speci- used for both subgrade and base/subbase materi- fications for the construction of airports. Ac- als. An additional...Texas. Details of the Texas method for deter- t Percentage of portion smaller than mining FS were reported by Carothers ( 1948 ) and 20mm were taken...material. pies are frozen from the bottom up at a constant rate of heat flow, similar to the method sug- Switzerland gested by Penner and Ueda (1978

Spatial accuracy of a simplified disaggregation method for traffic emissions applied in seven mid-sized Chilean cities

NASA Astrophysics Data System (ADS)

Ossés de Eicker, Margarita; Zah, Rainer; Triviño, Rubén; Hurni, Hans

The spatial accuracy of top-down traffic emission inventory maps obtained with a simplified disaggregation method based on street density was assessed in seven mid-sized Chilean cities. Each top-down emission inventory map was compared against a reference, namely a more accurate bottom-up emission inventory map from the same study area. The comparison was carried out using a combination of numerical indicators and visual interpretation. Statistically significant differences were found between the seven cities with regard to the spatial accuracy of their top-down emission inventory maps. In compact cities with a simple street network and a single center, a good accuracy of the spatial distribution of emissions was achieved with correlation values>0.8 with respect to the bottom-up emission inventory of reference. In contrast, the simplified disaggregation method is not suitable for complex cities consisting of interconnected nuclei, resulting in correlation values<0.5. Although top-down disaggregation of traffic emissions generally exhibits low accuracy, the accuracy is significantly higher in compact cities and might be further improved by applying a correction factor for the city center. Therefore, the method can be used by local environmental authorities in cities with limited resources and with little knowledge on the pollution situation to get an overview on the spatial distribution of the emissions generated by traffic activities.

A new approach for the construction of gridded emission inventories from satellite data

NASA Astrophysics Data System (ADS)

Kourtidis, Konstantinos; Georgoulias, Aristeidis; Mijling, Bas; van der A, Ronald; Zhang, Qiang; Ding, Jieying

2017-04-01

We present a new method for the derivation of anthropogenic emission estimates for SO2. The method, which we term Enhancement Ratio Method (ERM), uses observed relationships between measured OMI satellite tropospheric columnar levels of SO2 and NOx in each 0.25 deg X 0.25 deg grid box at low wind speeds, and the Daily Emission estimates Constrained by Satellite Observations (DECSO) versions v1 and v3a NOx emission estimates to scale the SO2 emissions. The method is applied over China, and emission estimates for SO2 are derived for different seasons and years (2007-2011), thus allowing an insight into the interannual evolution of the emissions. The inventory shows a large decrease of emissions during 2007-2009 and a modest increase between 2010-2011. The evolution in emission strength over time calculated here is in general agreement with bottom-up inventories, although differences exist, not only between the current inventory and other inventories but also among the bottom up inventories themselves. The gridded emission estimates derived appear to be consistent, both in their spatial distribution and their magnitude, with the Multi-resolution Emission Inventory for China (MEIC). The total emissions correlate very well with most existing inventories. This research has been financed under the FP7 Programme MarcoPolo (Grand Number 606953, Theme SPA.2013.3.2-01).

A bottom-up art event gave birth to a process of community empowerment in an Italian village.

PubMed

Sardu, Claudia; Mereu, Alessandra; Sotgiu, Alessandra; Contu, Paolo

2012-03-01

Although community participation is a component of community empowerment, it often remains a theoretical exhortation. Reporting experiences which enable people to take control of their lives, can be useful to suggest practical elements for promoting empowerment. This article describes the experience of a Sardinian village (Ulassai), that developed into a community empowerment. The Laverack's operational domains were used to measure the community empowerment process. The process started in 1979 'almost by chance' with an art performance that was the entry point for community participation. This experience has been the foundation for the community empowerment. Citizens acquired the 'ability of thinking and planning as a community and not mere individuals'. In the following 30 years citizens gave birth to several outcomes rooted in that event. The intermediate outcomes highlight the 'ability of action by a group to mobilize existing resources, and act collectively against opposing forces'. The long-term outcomes demonstrate the 'ability to integrate the cultural experiences that strengthened the community's identification into a sustainable community asset', and the 'ability to cope with global environmental challenges and to collaborate on an equal basis with other stakeholders. The pathways to community empowerment, showed by the community of Ulassai, overlap with the 'operational domains'. The Ulassai experience shows that the empowerment process can start from an event apparently unrelated to health promotion. This community experience illustrates the positive role arts can play in community development. Hence, the call for health promoters to look carefully into those situations that occur naturally in communities.

Survival on antiretroviral treatment among adult HIV-infected patients in Nepal: a retrospective cohort study in far-western Region, 2006–2011

PubMed Central

2013-01-01

Background Though financial and policy level efforts are made to expand antiretroviral treatment (ART) service free of cost, survival outcome of ART program has not been systematically evaluated in Nepal. This study assesses the mortality rates and determinants among adult HIV-infected patients on ART in Far-western region of Nepal. Methods This retrospective cohort study included 1024 (51.2% men) HIV-infected patients aged ≥15 years, who started ART between May 15th 2006 and May 15th 2011 in five ART sites in the Far-western region, Nepal. Follow-up time was calculated from the date of ART initiation to date of death or censoring (loss to follow-up, transferred out, or 15 November 2011). Mortality rates (per 100 person-years) were calculated. Kaplan-Meier and Cox-regression models were used to estimate survival and explore determinants of mortality. Results The median follow-up time was 19.1 months. The crude mortality rate was 6.3 (95% confidence interval (CI) 5.3-7.6) but more than three-times higher in first 3 months after ART initiation (21.9 (95% CI 16.6- 28.8)). About 12% (83% men) of those newly initiated on ART died during follow-up. The independent determinants of mortality were male sex (hazard ratio (HR) 4.55, 95% CI 2.43-8.51), poor baseline performance scale (bedridden <50% of the day during the past month, HR 2.05, 95% CI 1.19-3.52; bedridden >50% of the day during the past month, HR 3.41, 95% CI 1.67-6.98 compared to normal activity), one standard deviation decrease in baseline bodyweight (HR 1.04, 95% CI 1.01-1.07), and poor WHO clinical stage (stage III, HR 2.96, 95% CI 1.31-6.69; stage IV, HR 3.28, 95% CI 1.30-8.29 compared to WHO clinical stage I or II). Conclusions High mortality was observed within the first 3 months of ART initiation. Patients with poor baseline clinical characteristics had higher mortality, especially men. Earlier initiation of ART through expanded testing and counselling should be encouraged in HIV-infected patients. PMID:24369908

High rates of virological failure and drug resistance in perinatally HIV-1-infected children and adolescents receiving lifelong antiretroviral therapy in routine clinics in Togo

PubMed Central

Salou, Mounerou; Dagnra, Anoumou Y; Butel, Christelle; Vidal, Nicole; Serrano, Laetitia; Takassi, Elom; Konou, Abla A; Houndenou, Spero; Dapam, Nina; Singo-Tokofaï, Assetina; Pitche, Palokinam; Atakouma, Yao; Prince-David, Mireille; Delaporte, Eric; Peeters, Martine

2016-01-01

Introduction Antiretroviral treatment (ART) has been scaled up over the last decade but compared to adults, children living with HIV are less likely to receive ART. Moreover, children and adolescents are more vulnerable than adults to virological failure (VF) and emergence of drug resistance. In this study we determined virological outcome in perinatally HIV-1-infected children and adolescents receiving ART in Togo. Methods HIV viral load (VL) testing was consecutively proposed to all children and adolescents who were on ART for at least 12 months when attending HIV healthcare services for their routine follow-up visit (June to September 2014). Plasma HIV-1 VL was measured using the m2000 RealTime HIV-1 assay (Abbott Molecular, Des Plaines, IL, USA). Genotypic drug resistance was done for all samples with VL>1000 copies/ml. Results and discussion Among 283 perinatally HIV-1-infected children and adolescents included, 167 (59%) were adolescents and 116 (41%) were children. The median duration on ART was 48 months (interquartile range: 28 to 68 months). For 228 (80.6%), the current ART combination consisted of two nucleoside reverse transcriptase inhibitors (NRTIs) (zidovudine and lamivudine) and one non-nucleoside reverse transcriptase inhibitor (NNRTI) (nevirapine or efavirenz). Only 28 (9.9%) were on a protease inhibitor (PI)-based regimen. VL was below the detection limit (i.e. 40 copies/ml) for 102 (36%), between 40 and 1000 copies/ml for 35 (12.4%) and above 1000 copies/ml for 146 (51.6%). Genotypic drug-resistance testing was successful for 125/146 (85.6%); 110/125 (88.0%) were resistant to both NRTIs and NNRTIs, 1/125 (0.8%) to NRTIs only, 4/125 (3.2%) to NNRTIs only and three harboured viruses resistant to reverse transcriptase and PIs. Overall, 86% (108/125) of children and adolescents experiencing VF and successfully genotyped, corresponding thus to at least 38% of the study population, had either no effective ART or had only a single effective drug in their current ART regimen. Conclusions Our study provided important information on virological outcome on lifelong ART in perinatally HIV-1-infected children and adolescents who were still on ART and continued to attend antiretroviral (ARV) clinics for follow-up visits. Actual conditions for scaling up and monitoring lifelong ART in children in resource-limited countries can have dramatic long-term outcomes and illustrate that paediatric ART receives inadequate attention. PMID:27125320

An Adaptive Cross-Architecture Combination Method for Graph Traversal

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

You, Yang; Song, Shuaiwen; Kerbyson, Darren J.

2014-06-18

Breadth-First Search (BFS) is widely used in many real-world applications including computational biology, social networks, and electronic design automation. The combination method, using both top-down and bottom-up techniques, is the most effective BFS approach. However, current combination methods rely on trial-and-error and exhaustive search to locate the optimal switching point, which may cause significant runtime overhead. To solve this problem, we design an adaptive method based on regression analysis to predict an optimal switching point for the combination method at runtime within less than 0.1% of the BFS execution time.

Scale invariant feature transform in adaptive radiation therapy: a tool for deformable image registration assessment and re-planning indication

NASA Astrophysics Data System (ADS)

Paganelli, Chiara; Peroni, Marta; Riboldi, Marco; Sharp, Gregory C.; Ciardo, Delia; Alterio, Daniela; Orecchia, Roberto; Baroni, Guido

2013-01-01

Adaptive radiation therapy (ART) aims at compensating for anatomic and pathological changes to improve delivery along a treatment fraction sequence. Current ART protocols require time-consuming manual updating of all volumes of interest on the images acquired during treatment. Deformable image registration (DIR) and contour propagation stand as a state of the ART method to automate the process, but the lack of DIR quality control methods hinder an introduction into clinical practice. We investigated the scale invariant feature transform (SIFT) method as a quantitative automated tool (1) for DIR evaluation and (2) for re-planning decision-making in the framework of ART treatments. As a preliminary test, SIFT invariance properties at shape-preserving and deformable transformations were studied on a computational phantom, granting residual matching errors below the voxel dimension. Then a clinical dataset composed of 19 head and neck ART patients was used to quantify the performance in ART treatments. For the goal (1) results demonstrated SIFT potential as an operator-independent DIR quality assessment metric. We measured DIR group systematic residual errors up to 0.66 mm against 1.35 mm provided by rigid registration. The group systematic errors of both bony and all other structures were also analyzed, attesting the presence of anatomical deformations. The correct automated identification of 18 patients who might benefit from ART out of the total 22 cases using SIFT demonstrated its capabilities toward goal (2) achievement.

Improving Heat Transfer at the Bottom of Vials for Consistent Freeze Drying with Unidirectional Structured Ice.

PubMed

Rosa, Mónica; Tiago, João M; Singh, Satish K; Geraldes, Vítor; Rodrigues, Miguel A

2016-10-01

The quality of lyophilized products is dependent of the ice structure formed during the freezing step. Herein, we evaluate the importance of the air gap at the bottom of lyophilization vials for consistent nucleation, ice structure, and cake appearance. The bottom of lyophilization vials was modified by attaching a rectified aluminum disc with an adhesive material. Freezing was studied for normal and converted vials, with different volumes of solution, varying initial solution temperature (from 5°C to 20°C) and shelf temperature (from -20°C to -40°C). The impact of the air gap on the overall heat transfer was interpreted with the assistance of a computational fluid dynamics model. Converted vials caused nucleation at the bottom and decreased the nucleation time up to one order of magnitude. The formation of ice crystals unidirectionally structured from bottom to top lead to a honeycomb-structured cake after lyophilization of a solution with 4% mannitol. The primary drying time was reduced by approximately 35%. Converted vials that were frozen radially instead of bottom-up showed similar improvements compared with normal vials but very poor cake quality. Overall, the curvature of the bottom of glass vials presents a considerable threat to consistency by delaying nucleation and causing radial ice growth. Rectifying the vials bottom with an adhesive material revealed to be a relatively simple alternative to overcome this inconsistency.

Lipoaspirate fluid proteome: A preliminary investigation by LC-MS top-down/bottom-up integrated platform of a high potential biofluid in regenerative medicine.

PubMed

Inserra, Ilaria; Martelli, Claudia; Cipollina, Mara; Cicione, Claudia; Iavarone, Federica; Taranto, Giuseppe Di; Barba, Marta; Castagnola, Massimo; Desiderio, Claudia; Lattanzi, Wanda

2016-04-01

The lipoaspirate fluid (LAF) is emerging as a potentially valuable source in regenerative medicine. In particular, our group recently demonstrated that it is able to exert osteoinductive properties in vitro. This original observation stimulated the investigation of the proteomic component of LAF, by means of LC-ESI-LTQ-Orbitrap-MS top-down/bottom-up integrated approach, which represents the object of the present study. Top-down analyses required the optimization of sample pretreatment procedures to enable the correct investigation of the intact proteome. Bottom-up analyses have been directly applied to untreated samples after monodimensional SDS-PAGE separation. The analysis of the acid-soluble fraction of LAF by top-down approach allowed demonstrating the presence of albumin and hemoglobin fragments (i.e. VV- and LVV-hemorphin-7), thymosins β4 and β10 peptides, ubiquitin and acyl-CoA binding protein; adipogenesis regulatory factor, perilipin-1 fragments, and S100A6, along with their PTMs. Part of the bottom-up proteomic profile was reproducibly found in both tested samples. The bottom-up approach allowed demonstrating the presence of proteins, listed among the components of adipose tissue and/or comprised within the ASCs intracellular content and secreted proteome. Our data provide a first glance on the LAF molecular profile, which is consistent with its tissue environment. LAF appeared to contain bioactive proteins, peptides and paracrine factors, suggesting its potential translational exploitation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dissociable effects of top-down and bottom-up attention during episodic encoding

PubMed Central

Uncapher, Melina R.; Hutchinson, J. Benjamin; Wagner, Anthony D.

2011-01-01

It is well established that the formation of memories for life’s experiences—episodic memory—is influenced by how we attend to those experiences, yet the neural mechanisms by which attention shapes episodic encoding are still unclear. We investigated how top-down and bottom-up attention contribute to memory encoding of visual objects in humans by manipulating both types of attention during functional magnetic resonance imaging (fMRI) of episodic memory formation. We show that dorsal parietal cortex—specifically, intraparietal sulcus (IPS)—was engaged during top-down attention and was also recruited during the successful formation of episodic memories. By contrast, bottom-up attention engaged ventral parietal cortex—specifically, temporoparietal junction (TPJ)—and was also more active during encoding failure. Functional connectivity analyses revealed further dissociations in how top-down and bottom-up attention influenced encoding: while both IPS and TPJ influenced activity in perceptual cortices thought to represent the information being encoded (fusiform/lateral occipital cortex), they each exerted opposite effects on memory encoding. Specifically, during a preparatory period preceding stimulus presentation, a stronger drive from IPS was associated with a higher likelihood that the subsequently attended stimulus would be encoded. By contrast, during stimulus processing, stronger connectivity with TPJ was associated with a lower likelihood the stimulus would be successfully encoded. These findings suggest that during encoding of visual objects into episodic memory, top-down and bottom-up attention can have opposite influences on perceptual areas that subserve visual object representation, suggesting that one manner in which attention modulates memory is by altering the perceptual processing of to-be-encoded stimuli. PMID:21880922

Selective Activation of the Deep Layers of the Human Primary Visual Cortex by Top-Down Feedback.

PubMed

Kok, Peter; Bains, Lauren J; van Mourik, Tim; Norris, David G; de Lange, Floris P

2016-02-08

In addition to bottom-up input, the visual cortex receives large amounts of feedback from other cortical areas [1-3]. One compelling example of feedback activation of early visual neurons in the absence of bottom-up input occurs during the famous Kanizsa illusion, where a triangular shape is perceived, even in regions of the image where there is no bottom-up visual evidence for it. This illusion increases the firing activity of neurons in the primary visual cortex with a receptive field on the illusory contour [4]. Feedback signals are largely segregated from feedforward signals within each cortical area, with feedforward signals arriving in the middle layer, while top-down feedback avoids the middle layers and predominantly targets deep and superficial layers [1, 2, 5, 6]. Therefore, the feedback-mediated activity increase in V1 during the perception of illusory shapes should lead to a specific laminar activity profile that is distinct from the activity elicited by bottom-up stimulation. Here, we used fMRI at high field (7 T) to empirically test this hypothesis, by probing the cortical response to illusory figures in human V1 at different cortical depths [7-14]. We found that, whereas bottom-up stimulation activated all cortical layers, feedback activity induced by illusory figures led to a selective activation of the deep layers of V1. These results demonstrate the potential for non-invasive recordings of neural activity with laminar specificity in humans and elucidate the role of top-down signals during perceptual processing. Copyright © 2016 Elsevier Ltd. All rights reserved.

Pregnant women with HIV in rural Nigeria have higher rates of antiretroviral treatment initiation, but similar loss to follow-up as non-pregnant women and men

PubMed Central

Aliyu, Muktar H.; Blevins, Meridith; Megazzini, Karen M.; Parrish, Deidra D.; Audet, Carolyn M.; Chan, Naomi; Odoh, Chisom; Gebi, Usman I.; Muhammad, Mukhtar Y.; Shepherd, Bryan E.; Wester, C. William; Vermund, Sten H.

2015-01-01

Background We examined antiretroviral therapy (ART) initiation and retention by sex and pregnancy status in rural Nigeria. Methods We studied HIV-infected ART-naïve patients aged ≥15 years entering care from June 2009 to September 2013. We calculated the probability of early ART initiation and cumulative incidence of loss to follow-up (LTFU) during the first year of ART, and examined the association between LTFU and sex/pregnancy using Cox regression. Results The cohort included 3813 ART-naïve HIV-infected adults (2594 women [68.0%], 273 [11.8%] of them pregnant). The proportion of pregnant clients initiating ART within 90 days of enrollment (78.0%, 213/273) was higher than among non-pregnant women (54.3%,1261/2321) or men (53.0%, 650/1219), both p<0.001. Pregnant women initiated ART sooner than non-pregnant women and men (median [IQR] days from enrollment to ART initiation for pregnant women=7 days [0–21] vs 14 days [7–49] for non-pregnant women and 14 days [7–42] for men; p<0.001). Cumulative incidence of LTFU during the first year post-ART initiation was high and did not differ by sex and pregnancy status. Persons who were unemployed, bedridden, had higher CD4+ counts, and/or in earlier WHO clinical stages were more likely to be LTFU. Conclusions Pregnant women with HIV in rural Nigeria were more likely to initiate ART but were no more likely to be retained in care. Our findings underscore the importance of effective retention strategies across all patient groups, regardless of sex and pregnancy status. PMID:26012740

The Roles of Feature-Specific Task Set and Bottom-Up Salience in Attentional Capture: An ERP Study

ERIC Educational Resources Information Center

Eimer, Martin; Kiss, Monika; Press, Clare; Sauter, Disa

2009-01-01

We investigated the roles of top-down task set and bottom-up stimulus salience for feature-specific attentional capture. Spatially nonpredictive cues preceded search arrays that included a color-defined target. For target-color singleton cues, behavioral spatial cueing effects were accompanied by cue-induced N2pc components, indicative of…

Students' Perceptions about Online Teaching Effectiveness: A Bottom-Up Approach for Identifying Online Instructors' Roles

ERIC Educational Resources Information Center

Gómez-Rey, Pilar; Barbera, Elena; Fernández-Navarro, Francisco

2018-01-01

The topic of online instructors' roles has been of interest to the educational community since the late twentieth century. In previous studies, the identification of online instructors' roles was done using a top-down (deductive) approach. This study applied a bottom-up (inductive) procedure to examine not only the roles of online instructors from…

Bottom-up processes influence the demography and life-cycle phenology of Hawaiian bird communities

Treesearch

Jared D. Wolfe; C. John Ralph; Andrew Wiegardt

2017-01-01

Changes in climate can indirectly regulate populations at higher trophic levels by influencing the availability of food resources in the lower reaches of the food web. As such, species that rely on fruit and nectar food resources may be particularly sensitive to these bottom-up perturbations due to the strength of their trophic linkages with climatically-...

The Role of Bottom-Up Processing in Perceptual Categorization by 3- to 4-Month-Old Infants: Simulations and Data

ERIC Educational Resources Information Center

French, Robert M.; Mareschal, Denis; Mermillod, Martial; Quinn, Paul C.

2004-01-01

Disentangling bottom-up and top-down processing in adult category learning is notoriously difficult. Studying category learning in infancy provides a simple way of exploring category learning while minimizing the contribution of top-down information. Three- to 4-month-old infants presented with cat or dog images will form a perceptual category…

Second Language Listening Instruction: Comparing a Strategies-Based Approach with an Interactive, Strategies/Bottom-Up Skills Approach

ERIC Educational Resources Information Center

Yeldham, Michael

2016-01-01

This quasi-experimental study compared a strategies approach to second language listening instruction with an interactive approach, one combining a roughly equal balance of strategies and bottom-up skills. The participants were lower-intermediate-level Taiwanese university EFL learners, who were taught for 22 hours over one and a half semesters.…

On the Temporal Relation of Top-Down and Bottom-Up Mechanisms during Guidance of Attention

ERIC Educational Resources Information Center

Wykowska, Agnieszka; Schubo, Anna

2010-01-01

Two mechanisms are said to be responsible for guiding focal attention in visual selection: bottom-up, saliency-driven capture and top-down control. These mechanisms were examined with a paradigm that combined a visual search task with postdisplay probe detection. Two SOAs between the search display and probe onsets were introduced to investigate…

Citizenship Policy from the Bottom-Up: The Linguistic and Semiotic Landscape of a Naturalization Field Office

ERIC Educational Resources Information Center

Loring, Ariel

2015-01-01

This article follows a bottom-up approach to language policy (Ramanathan, 2005; Wodak, 2006) in an analysis of citizenship in policy and practice. It compares representations of citizenship in and around a regional branch of the United States Citizenship and Immigration Services (USCIS), with a focus on citizenship swearing-in ceremonies for…

Micelle-templated, poly(lactic-co-glycolic acid) nanoparticles for hydrophobic drug delivery

PubMed Central

Nabar, Gauri M; Mahajan, Kalpesh D; Calhoun, Mark A; Duong, Anthony D; Souva, Matthew S; Xu, Jihong; Czeisler, Catherine; Puduvalli, Vinay K; Otero, José Javier; Wyslouzil, Barbara E; Winter, Jessica O

2018-01-01

Purpose Poly(lactic-co-glycolic acid) (PLGA) is widely used for drug delivery because of its biocompatibility, ability to solubilize a wide variety of drugs, and tunable degradation. However, achieving sub-100 nm nanoparticles (NPs), as might be desired for delivery via the enhanced permeability and retention effect, is extremely difficult via typical top-down emulsion approaches. Methods Here, we present a bottom-up synthesis method yielding PLGA/block copolymer hybrids (ie, “PolyDots”), consisting of hydrophobic PLGA chains entrapped within self-assembling poly(styrene-b-ethylene oxide) (PS-b-PEO) micelles. Results PolyDots exhibit average diameters <50 nm and lower polydispersity than conventional PLGA NPs. Drug encapsulation efficiencies of PolyDots match conventional PLGA NPs (ie, ~30%) and are greater than those obtained from PS-b-PEO micelles (ie, ~7%). Increasing the PLGA:PS-b-PEO weight ratio alters the drug release mechanism from chain relaxation to erosion controlled. PolyDots are taken up by model glioma cells via endocytotic mechanisms within 24 hours, providing a potential means for delivery to cytoplasm. PolyDots can be lyophilized with minimal change in morphology and encapsulant functionality, and can be produced at scale using electrospray. Conclusion Encapsulation of PLGA within micelles provides a bottom-up route for the synthesis of sub-100 nm PLGA-based nanocarriers with enhanced stability and drug-loading capacity, and tunable drug release, suitable for potential clinical applications. PMID:29391794

Bottom-up and top-down fabrication of nanowire-based electronic devices: In situ doping of vapor liquid solid grown silicon nanowires and etch-dependent leakage current in InGaAs tunnel junctions

NASA Astrophysics Data System (ADS)

Kuo, Meng-Wei

Semiconductor nanowires are important components in future nanoelectronic and optoelectronic device applications. These nanowires can be fabricated using either bottom-up or top-down methods. While bottom-up techniques can achieve higher aspect ratio at reduced dimension without having surface and sub-surface damage, uniform doping distributions with abrupt junction profiles are less challenging for top-down methods. In this dissertation, nanowires fabricated by both methods were systematically investigated to understand: (1) the in situ incorporation of boron (B) dopants in Si nanowires grown by the bottom-up vapor-liquid-solid (VLS) technique, and (2) the impact of plasma-induced etch damage on InGaAs p +-i-n+ nanowire junctions for tunnel field-effect transistors (TFETs) applications. In Chapter 2 and 3, the in situ incorporation of B in Si nanowires grown using silane (SiH4) or silicon tetrachloride (SiCl4) as the Si precursor and trimethylboron (TMB) as the p-type dopant source is investigated by I-V measurements of individual nanowires. The results from measurements using a global-back-gated test structure reveal nonuniform B doping profiles on nanowires grown from SiH4, which is due to simultaneous incorporation of B from nanowire surface and the catalyst during VLS growth. In contrast, a uniform B doping profile in both the axial and radial directions is achieved for TMBdoped Si nanowires grown using SiCl4 at high substrate temperatures. In Chapter 4, the I-V characteristics of wet- and dry-etched InGaAs p+-i-n+ junctions with different mesa geometries, orientations, and perimeter-to-area ratios are compared to evaluate the impact of the dry etch process on the junction leakage current properties. Different post-dry etch treatments, including wet etching and thermal annealing, are performed and the effectiveness of each is assessed by temperaturedependent I-V measurements. As compared to wet-etched control devices, dry-etched junctions have a significantly higher leakage current and a current kink in the reverse bias regime, which is likely due to additional trap states created by plasma-induced damage during the Cl2/Ar/H2 mesa isolation step. These states extend more than 60 nm from the mesa surface and can only be partially passivated after a thermal anneal at 350°C for 20 minutes. The evolution of the electrical properties with post-dry etch treatments indicates that the shallow and deep-level trap states resulting from ion-induced point defects, arsenic vacancies and hydrogen-dopant complexes are the primary cause of degradation in the electrical properties of the dry-etched junctions.

Wide Differences in the Estimation of Cost in Endovenous Laser Therapy for Varicose Veins

NASA Astrophysics Data System (ADS)

Lattimer, Christopher R.; Piper, Stephen; Kalodiki, Evi; Trueman, Paul; Geroulakos, George

2011-08-01

PURPOSE: To investigate differences in cost of endovenous laser therapy (EVLT) using a top-down approach derived from the Annual Report versus a clinically orientated, bottom-up approach at a single hospital. METHODS: Information was obtained from: the day-case activity Service Line Report (SLR) income statement for general surgery, comparative data from the National Audit Commission, reference costs from the hospital finance department on 69 patients and calculations on individual treatment times and session slots (2 EVLT's per 3.5 hr session) on 37 consecutive patients. Duration of treatment, consumables (over £3) and staff pay were also recorded. Overheads were estimated at 15% and adjustments were made based on location and length of stay. RESULTS: Using a top-down approach with SLR data the total cost of EVLT was estimated at £963.78 per treatment after adjustments for services and consumables. This compares with £1,073.34 using national data. The hospital reference costs per treatment ranged from £767.56 overall by local procedure code (HRG-QZ10B) to £2,353.79 with individual samples. In the bottom-up approach median duration of EVLT was 86 mins (95% CI: 82-95, IQR: 26). With timed treatments median cost per individual treatment was £597.68 (95% CI: 587.65-621.25, IQR: 67.87) compared to £647.28 per session slot. CONCLUSION: Cost estimations of EVLT demonstrate an up to 4-fold difference. Lack of clinical engagement in the top-down approach leads to overestimations. Overheads are underestimated with a bottom-up approach. This variability should be accounted when comparing treatments or interpreting cost-effectiveness analyses.

Evaluation of three sampling methods to monitor outcomes of antiretroviral treatment programmes in low- and middle-income countries.

PubMed

Tassie, Jean-Michel; Malateste, Karen; Pujades-Rodríguez, Mar; Poulet, Elisabeth; Bennett, Diane; Harries, Anthony; Mahy, Mary; Schechter, Mauro; Souteyrand, Yves; Dabis, François

2010-11-10

Retention of patients on antiretroviral therapy (ART) over time is a proxy for quality of care and an outcome indicator to monitor ART programs. Using existing databases (Antiretroviral in Lower Income Countries of the International Databases to Evaluate AIDS and Médecins Sans Frontières), we evaluated three sampling approaches to simplify the generation of outcome indicators. We used individual patient data from 27 ART sites and included 27,201 ART-naive adults (≥15 years) who initiated ART in 2005. For each site, we generated two outcome indicators at 12 months, retention on ART and proportion of patients lost to follow-up (LFU), first using all patient data and then within a smaller group of patients selected using three sampling methods (random, systematic and consecutive sampling). For each method and each site, 500 samples were generated, and the average result was compared with the unsampled value. The 95% sampling distribution (SD) was expressed as the 2.5(th) and 97.5(th) percentile values from the 500 samples. Overall, retention on ART was 76.5% (range 58.9-88.6) and the proportion of patients LFU, 13.5% (range 0.8-31.9). Estimates of retention from sampling (n = 5696) were 76.5% (SD 75.4-77.7) for random, 76.5% (75.3-77.5) for systematic and 76.0% (74.1-78.2) for the consecutive method. Estimates for the proportion of patients LFU were 13.5% (12.6-14.5), 13.5% (12.6-14.3) and 14.0% (12.5-15.5), respectively. With consecutive sampling, 50% of sites had SD within ±5% of the unsampled site value. Our results suggest that random, systematic or consecutive sampling methods are feasible for monitoring ART indicators at national level. However, sampling may not produce precise estimates in some sites.

Top-Down-Assisted Bottom-Up Method for Homologous Protein Sequencing: Hemoglobin from 33 Bird Species

NASA Astrophysics Data System (ADS)

Song, Yang; Laskay, Ünige A.; Vilcins, Inger-Marie E.; Barbour, Alan G.; Wysocki, Vicki H.

2015-11-01

Ticks are vectors for disease transmission because they are indiscriminant in their feeding on multiple vertebrate hosts, transmitting pathogens between their hosts. Identifying the hosts on which ticks have fed is important for disease prevention and intervention. We have previously shown that hemoglobin (Hb) remnants from a host on which a tick fed can be used to reveal the host's identity. For the present research, blood was collected from 33 bird species that are common in the U.S. as hosts for ticks but that have unknown Hb sequences. A top-down-assisted bottom-up mass spectrometry approach with a customized searching database, based on variability in known bird hemoglobin sequences, has been devised to facilitate fast and complete sequencing of hemoglobin from birds with unknown sequences. These hemoglobin sequences will be added to a hemoglobin database and used for tick host identification. The general approach has the potential to sequence any set of homologous proteins completely in a rapid manner.

2D FT-ICR MS of Calmodulin: A Top-Down and Bottom-Up Approach.

PubMed

Floris, Federico; van Agthoven, Maria; Chiron, Lionel; Soulby, Andrew J; Wootton, Christopher A; Lam, Yuko P Y; Barrow, Mark P; Delsuc, Marc-André; O'Connor, Peter B

2016-09-01

Two-dimensional Fourier transform ion cyclotron resonance mass spectrometry (2D FT-ICR MS) allows data-independent fragmentation of all ions in a sample and correlation of fragment ions to their precursors through the modulation of precursor ion cyclotron radii prior to fragmentation. Previous results show that implementation of 2D FT-ICR MS with infrared multi-photon dissociation (IRMPD) and electron capture dissociation (ECD) has turned this method into a useful analytical tool. In this work, IRMPD tandem mass spectrometry of calmodulin (CaM) has been performed both in one-dimensional and two-dimensional FT-ICR MS using a top-down and bottom-up approach. 2D IRMPD FT-ICR MS is used to achieve extensive inter-residue bond cleavage and assignment for CaM, using its unique features for fragment identification in a less time- and sample-consuming experiment than doing the same thing using sequential MS/MS experiments. Graphical Abstract ᅟ.

Bottom-up photonic crystal cavities formed by patterned III-V nanopillars.

PubMed

Scofield, Adam C; Shapiro, Joshua N; Lin, Andrew; Williams, Alex D; Wong, Ping-Show; Liang, Baolai L; Huffaker, Diana L

2011-06-08

We report on the formation and optical properties of bottom-up photonic crystal (PC) cavities formed by III-V nanopillars (NPs) via catalyst-free selective-area metal-organic chemical vapor deposition on masked GaAs substrates. This method of NP synthesis allows for precise lithographic control of NP position and diameter enabling simultaneous formation of both the photonic band gap (PBG) region and active gain region. The PBG and cavity resonance are determined by independently tuning the NP radius r, pitch a, and height h in the respective masked areas. Near-infrared emission at 970 nm is achieved from axial GaAs/InGaAs heterostructures with in situ passivation by laterally grown InGaP shells. To achieve out-of-plane optical confinement, the PC cavities are embedded in polydimethylsiloxane (PDMS) and removed from the growth substrate. Spatially and spectrally resolved 77 K photoluminescence demonstrates a strong influence of the PBG resonance on device emission. Resonant peaks are observed in the emission spectra of PC cavities embedded in PDMS.

Comparing top-down and bottom-up costing approaches for economic evaluation within social welfare.

PubMed

Olsson, Tina M

2011-10-01

This study compares two approaches to the estimation of social welfare intervention costs: one "top-down" and the other "bottom-up" for a group of social welfare clients with severe problem behavior participating in a randomized trial. Intervention costs ranging over a two-year period were compared by intervention category (foster care placement, institutional placement, mentorship services, individual support services and structured support services), estimation method (price, micro costing, average cost) and treatment group (intervention, control). Analyses are based upon 2007 costs for 156 individuals receiving 404 interventions. Overall, both approaches were found to produce reliable estimates of intervention costs at the group level but not at the individual level. As choice of approach can greatly impact the estimate of mean difference, adjustment based on estimation approach should be incorporated into sensitivity analyses. Analysts must take care in assessing the purpose and perspective of the analysis when choosing a costing approach for use within economic evaluation.

Scaled CMOS Reliability and Considerations for Spacecraft Systems: Bottom-Up and Top-Down Perspective

NASA Technical Reports Server (NTRS)

White, Mark

2012-01-01

New space missions will increasingly rely on more advanced technologies because of system requirements for higher performance, particularly in instruments and high-speed processing. Component-level reliability challenges with scaled CMOS in spacecraft systems from a bottom-up perspective have been presented. Fundamental Front-end and Back-end processing reliability issues with more aggressively scaled parts have been discussed. Effective thermal management from system-level to the componentlevel (top-down) is a key element in overall design of reliable systems. Thermal management in space systems must consider a wide range of issues, including thermal loading of many different components, and frequent temperature cycling of some systems. Both perspectives (top-down and bottom-up) play a large role in robust, reliable spacecraft system design.

Submarine pipeline on-bottom stability. Volume 2: Software and manuals

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

NONE

1998-12-01

The state-of-the-art in pipeline stability design has been changing very rapidly recent. The physics governing on-bottom stability are much better understood now than they were eight years. This is due largely because of research and large scale model tests sponsored by PRCI. Analysis tools utilizing this new knowledge have been developed. These tools provide the design engineer with a rational approach have been developed. These tools provide the design engineer with a rational approach for weight coating design, which he can use with confidence because the tools have been developed based on full scale and near full scale model tests.more » These tools represent the state-of-the-art in stability design and model the complex behavior of pipes subjected to both wave and current loads. These include: hydrodynamic forces which account for the effect of the wake (generated by flow over the pipe) washing back and forth over the pipe in oscillatory flow; and the embedment (digging) which occurs as a pipe resting on the seabed is exposed to oscillatory loadings and small oscillatory deflections. This report has been developed as a reference handbook for use in on-bottom pipeline stability analysis It consists of two volumes. Volume one is devoted descriptions of the various aspects of the problem: the pipeline design process; ocean physics, wave mechanics, hydrodynamic forces, and meteorological data determination; geotechnical data collection and soil mechanics; and stability design procedures. Volume two describes, lists, and illustrates the analysis software. Diskettes containing the software and examples of the software are also included in Volume two.« less

Loss to follow-up among children and adolescents growing up with HIV infection: age really matters

PubMed Central

Kranzer, Katharina; Bradley, John; Musaazi, Joseph; Nyathi, Mary; Gunguwo, Hilary; Ndebele, Wedu; Dixon, Mark; Ndhlovu, Mbongeni; Rehman, Andrea; Khan, Palwasha; Vogt, Florian; Apollo, Tsitsi; Ferrand, Rashida Abbas

2017-01-01

Abstract Introduction: Globally, increasing numbers of HIV-infected children are reaching adolescence due to antiretroviral therapy (ART). We investigated rates of loss-to-follow-up (LTFU) from HIV care services among children as they transition from childhood through adolescence. Methods: Individuals aged 5–19 years initiated on ART in a public-sector HIV clinic in Bulawayo, Zimbabwe, between 2005 and 2009 were included in a retrospective cohort study. Participants were categorized into narrow age-bands namely: 5–9 (children), 10–14 (young adolescents) and 15–19 (older adolescents). The effect of age at ART initiation, current age (using a time-updated Lexis expansion) and transitioning from one age group to the next on LTFU was estimated using Poisson regression. Results: Of 2273 participants, 1013, 875 and 385 initiated ART aged 5–9, 10–14 and 15–19 years, respectively. Unlike those starting ART as children, individuals starting ART as young adolescents had higher LTFU rates after moving to the older adolescent age-band (Adjusted rate ratio (ARR) 1.54; 95% CI: 0.94–2.55) and similarly, older adolescents had higher LTFU rates after transitioning to being young adults (ARR 1.79; 95% CI: 1.05–3.07). In older adolescents, the LTFU rate among those who started ART in that age-band was higher compared to the rate among those starting ART at a younger age (ARR = 1.70; 95% CI: 1.05, 2.77). This however did not hold true for other age-groups. Conclusions: Adolescents had higher rates of LTFU compared to other age-groups, with older adolescents at particularly high risk in all analyses. Age-updated analyses that examine movement across narrow age-bands are paramount in understanding how developmental heterogeneity in children affects HIV outcomes. PMID:28715158

Factors associated with death and loss to follow-up in children on antiretroviral care in Mingalardon Specialist Hospital, Myanmar, 2006-2016.

PubMed

Kaung Nyunt, Kay Khaing; Han, Wai Wai; Satyanarayana, Srinath; Isaakidis, Petros; Hone, San; Khaing, Aye Aye; Nguyen Binh, Hoa; Oo, Htun Nyunt

2018-01-01

Myanmar National AIDS programme's priority is to improve the survival of all people living with HIV by providing anti-retroviral therapy (ART) care. More than 7200 children (aged <15 years) have been enrolled into ART care from 2005 to 2016. A previous study showed that ~11% children on ART care had either died or were lost to follow-up by 60 months. Factors associated with death and lost-to follow-up (adverse outcomes) have not been previously studied. To describe the association between demographic and clinical characteristics at enrollment into ART care with adverse outcomes. Cohort study using records of children enrolled for ART care at Mingalardon Specialist Hospital (main Paediatric ART center in Myanmar) from 2006-2016. We used multivariable Cox proportional hazards regression models for analysis. 1,159 children were enrolled for ART care and they contributed a total of 1.45 million person-days of follow-up period. 112 (10%) had an adverse outcome during the follow-up time period (55 deaths, 57 lost to follow-up). Enrollment into the ART care through in-patient care department of the hospital, CD4 Cell count <50/mm3, enrollment during changing ART guidelines (different ART eligibility criteria and preferred ART regimen) were independently associated with higher hazards of adverse outcome. Receiving protease inhibitor-based ART regimen at enrollment was independently associated with lower hazards of adverse outcome. Age, sex, residing in urban or rural areas, WHO clinical stage, having TB at the time of enrollment, receiving cotrimoxazole prophylaxis were not statistically associated with adverse outcomes. Our analysis reconfirms good survival of children on ART care (including those with TB). The characteristics associated with adverse outcomes (other than CD4 cell count<50) are surrogates of some unmeasured underlying health system/ patient related factors that needs further exploration to improve the survival of children on ART care.

Considering the normative, systemic and procedural dimensions in indicator-based sustainability assessments in agriculture

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

Binder, Claudia R., E-mail: claudia.binder@geo.uzh.c; Institute for System Science, Innovation and Sustainability Research, University of Graz; Feola, Giuseppe

This paper develops a framework for evaluating sustainability assessment methods by separately analyzing their normative, systemic and procedural dimensions as suggested by Wiek and Binder [Wiek, A, Binder, C. Solution spaces for decision-making - a sustainability assessment tool for city-regions. Environ Impact Asses Rev 2005, 25: 589-608.]. The framework is then used to characterize indicator-based sustainability assessment methods in agriculture. For a long time, sustainability assessment in agriculture has focused mostly on environmental and technical issues, thus neglecting the economic and, above all, the social aspects of sustainability, the multi-functionality of agriculture and the applicability of the results. In responsemore » to these shortcomings, several integrative sustainability assessment methods have been developed for the agricultural sector. This paper reviews seven of these that represent the diversity of tools developed in this area. The reviewed assessment methods can be categorized into three types: (i) top-down farm assessment methods; (ii) top-down regional assessment methods with some stakeholder participation; (iii) bottom-up, integrated participatory or transdisciplinary methods with stakeholder participation throughout the process. The results readily show the trade-offs encountered when selecting an assessment method. A clear, standardized, top-down procedure allows for potentially benchmarking and comparing results across regions and sites. However, this comes at the cost of system specificity. As the top-down methods often have low stakeholder involvement, the application and implementation of the results might be difficult. Our analysis suggests that to include the aspects mentioned above in agricultural sustainability assessment, the bottom-up, integrated participatory or transdisciplinary methods are the most suitable ones.« less

The Macroeconomic Consequences of Renouncing to Universal Access to Antiretroviral Treatment for HIV in Africa: A Micro-Simulation Model

PubMed Central

Ventelou, Bruno; Arrighi, Yves; Greener, Robert; Lamontagne, Erik; Carrieri, Patrizia; Moatti, Jean-Paul

2012-01-01

Aim Previous economic literature on the cost-effectiveness of antiretroviral treatment (ART) programs has been mainly focused on the microeconomic consequences of alternative use of resources devoted to the fight against the HIV pandemic. We rather aim at forecasting the consequences of alternative scenarios for the macroeconomic performance of countries. Methods We used a micro-simulation model based on individuals aged 15–49 selected from nationally representative surveys (DHS for Cameroon, Tanzania and Swaziland) to compare alternative scenarios : 1-freezing of ART programs to current levels of access, 2- universal access (scaling up to 100% coverage by 2015, with two variants defining ART eligibility according to previous or current WHO guidelines). We introduced an “artificial” ageing process by programming methods. Individuals could evolve through different health states: HIV negative, HIV positive (with different stages of the syndrome). Scenarios of ART procurement determine this dynamics. The macroeconomic impact is obtained using sample weights that take into account the resulting age-structure of the population in each scenario and modeling of the consequences on total growth of the economy. Results Increased levels of ART coverage result in decreasing HIV incidence and related mortality. Universal access to ART has a positive impact on workers' productivity; the evaluations performed for Swaziland and Cameroon show that universal access would imply net cost-savings at the scale of the society, when the full macroeconomic consequences are introduced in the calculations. In Tanzania, ART access programs imply a net cost for the economy, but 70% of costs are covered by GDP gains at the 2034 horizon, even in the extended coverage option promoted by WHO guidelines initiating ART at levels of 350 cc/mm3 CD4 cell counts. Conclusion Universal Access ART scaling-up strategies, which are more costly in the short term, remain the best economic choice in the long term. Renouncing or significantly delaying the achievement of this goal, due to “legitimate” short term budgetary constraints would be a misguided choice. PMID:22514619

When does fishing lead to more fish? Community consequences of bottom trawl fisheries in demersal food webs

PubMed Central

van Denderen, P. Daniel; van Kooten, Tobias; Rijnsdorp, Adriaan D.

2013-01-01

Bottom trawls are a globally used fishing gear that physically disturb the seabed and kill non-target organisms, including those that are food for the targeted fish species. There are indications that ensuing changes to the benthic invertebrate community may increase the availability of food and promote growth and even fisheries yield of target fish species. If and how this occurs is the subject of ongoing debate, with evidence both in favour and against. We model the effects of trawling on a simple ecosystem of benthivorous fish and two food populations (benthos), susceptible and resistant to trawling. We show that the ecosystem response to trawling depends on whether the abundance of benthos is top-down or bottom-up controlled. Fishing may result in higher fish abundance, higher (maximum sustainable) yield and increased persistence of fish when the benthos which is the best-quality fish food is also more resistant to trawling. These positive effects occur in bottom-up controlled systems and systems with limited impact of fish feeding on benthos, resembling bottom-up control. Fishing leads to lower yields and fish persistence in all configurations where susceptible benthos are more profitable prey. Our results highlight the importance of mechanistic ecosystem knowledge as a requirement for successful management. PMID:24004941

Top-down and bottom-up modeling in system pharmacology to understand clinical efficacy: An example with NRTIs of HIV-1.

PubMed

Duwal, Sulav; von Kleist, Max

2016-10-30

A major aim of Systems Pharmacology is to understand clinically relevant mechanisms of action (MOA) of drugs and to use this knowledge in order to optimize therapy. To enable this mission it is necessary to obtain knowledge on how in vitro testable insights translate into clinical efficacy. Mathematical modeling and data integration are essential components to achieve this goal. Two modeling philosophies are prevalent, each of which in isolation is not sufficient to achieve the above described: In a 'top-down' approach, a minimal pharmacokinetic-pharmacodynamic (PK-PD) model is derived from- and fitted to available clinical data. This model may lack interpretability in terms of mechanisms and may only be predictive for scenarios already covered by the data used to derive it. A 'bottom-up' approach builds on mechanistic insights derived from in vitro/ex vivo experiments, which can be conducted under controlled conditions, but may not be fully representative for the in vivo/clinical situation. In this work, we employ both approaches side-by-side to predict the clinical potency (IC 50 values) of the nucleoside reverse transcriptase inhibitors (NRTIs) lamivudine, emtricitabine and tenofovir. In the 'top-down' approach, this requires to establish the dynamic link between the intracellularly active NRTI-triphosphates (which exert the effect) and plasma prodrug PK and to subsequently link this composite PK model to viral kinetics. The 'bottom-up' approach assesses inhibition of reverse transcriptase-mediated viral DNA polymerization by the intracellular, active NRTI-triphosphates, which has to be brought into the context of target cell infection. By using entirely disparate sets of data to derive and parameterize the respective models, our approach serves as a means to assess the clinical relevance of the 'bottom-up' approach. We obtain very good qualitative and quantitative agreement between 'top-down' vs. 'bottom-up' predicted IC 50 values, arguing for the validity of the 'bottom-up' approach. We noted, however, that the 'top-down' approach is strongly dependent on the sparse and noisy intracellular pharmacokinetic data. All in all, our work provides confidence that we can translate in vitro parameters into measures of clinical efficacy using the 'bottom-up' approach. This may allow to infer the potency of various NRTIs in inhibiting e.g. mutant viruses, to distinguish sources of interaction of NRTI combinations and to assess the efficacy of different NRTIs for repurposing, e.g. for pre-exposure prophylaxis. Copyright © 2016 Elsevier B.V. All rights reserved.

Inverse Estimation of California Methane Emissions and Their Uncertainties using FLEXPART-WRF

NASA Astrophysics Data System (ADS)

Cui, Y.; Brioude, J. F.; Angevine, W. M.; McKeen, S. A.; Peischl, J.; Nowak, J. B.; Henze, D. K.; Bousserez, N.; Fischer, M. L.; Jeong, S.; Liu, Z.; Michelsen, H. A.; Santoni, G.; Daube, B. C.; Kort, E. A.; Frost, G. J.; Ryerson, T. B.; Wofsy, S. C.; Trainer, M.

2015-12-01

Methane (CH4) has a large global warming potential and mediates global tropospheric chemistry. In California, CH4 emissions estimates derived from "top-down" methods based on atmospheric observations have been found to be greater than expected from "bottom-up" population-apportioned national and state inventories. Differences between bottom-up and top-down estimates suggest that the understanding of California's CH4 sources is incomplete, leading to uncertainty in the application of regulations to mitigate regional CH4 emissions. In this study, we use airborne measurements from the California research at the Nexus of Air Quality and Climate Change (CalNex) campaign in 2010 to estimate CH4 emissions in the South Coast Air Basin (SoCAB), which includes California's largest metropolitan area (Los Angeles), and in the Central Valley, California's main agricultural and livestock management area. Measurements from 12 daytime flights, prior information from national and regional official inventories (e.g. US EPA's National Emission Inventory, the California Air Resources Board inventories, the Liu et al. Hybrid Inventory, and the California Greenhouse Gas Emissions Measurement dataset), and the FLEXPART-WRF transport model are used in our mesoscale Bayesian inverse system. We compare our optimized posterior CH4 inventory to the prior bottom-up inventories in terms of total emissions (Mg CH4/hr) and the spatial distribution of the emissions (0.1 degree), and quantify uncertainties in our posterior estimates. Our inversions show that the oil and natural gas industry (extraction, processing and distribution) is the main source accounting for the gap between top-down and bottom-up inventories over the SoCAB, while dairy farms are the largest CH4 source in the Central Valley. CH4 emissions of dairy farms in the San Joaquin Valley and variations of CH4 emissions in the rice-growing regions of Sacramento Valley are quantified and discussed. We also estimate CO and NH3 surface fluxes and use their observed correlation with CH4 mixing ratio to further evaluate our CH4 total emission estimates, and understand the spatial distribution of CH4 emissions.

A Clash of Bottom-Up and Top-Down Processes in Visual Search: The Reversed Letter Effect Revisited

ERIC Educational Resources Information Center

Zhaoping, Li; Frith, Uta

2011-01-01

It is harder to find the letter "N" among its mirror reversals than vice versa, an inconvenient finding for bottom-up saliency accounts based on primary visual cortex (V1) mechanisms. However, in line with this account, we found that in dense search arrays, gaze first landed on either target equally fast. Remarkably, after first landing,…

Bottom-Up Mechanisms Are Involved in the Relation between Accuracy in Timing Tasks and Intelligence--Further Evidence Using Manipulations of State Motivation

ERIC Educational Resources Information Center

Ullen, Fredrik; Soderlund, Therese; Kaaria, Lenita; Madison, Guy

2012-01-01

Intelligence correlates with accuracy in various timing tasks. Such correlations could be due to both bottom-up mechanisms, e.g. neural properties that influence both temporal accuracy and cognitive processing, and differences in top-down control. We have investigated the timing-intelligence relation using a simple temporal motor task, isochronous…

Trends in detectable viral load by calendar year in the Australian HIV observational database.

PubMed

Law, Matthew G; Woolley, Ian; Templeton, David J; Roth, Norm; Chuah, John; Mulhall, Brian; Canavan, Peter; McManus, Hamish; Cooper, David A; Petoumenos, Kathy

2011-02-23

Recent papers have suggested that expanded combination antiretroviral treatment (cART) through lower viral load may be a strategy to reduce HIV transmission at a population level. We assessed calendar trends in detectable viral load in patients recruited to the Australian HIV Observational Database who were receiving cART. Patients were included in analyses if they had started cART (defined as three or more antiretrovirals) and had at least one viral load assessment after 1 January 1997. We analyzed detectable viral load (>400 copies/ml) in the first and second six months of each calendar year while receiving cART. Repeated measures logistic regression methods were used to account for within and between patient variability. Rates of detectable viral load were predicted allowing for patients lost to follow up. Analyses were based on 2439 patients and 31,339 viral load assessments between 1 January 1997 and 31 March 2009. Observed detectable viral load in patients receiving cART declined to 5.3% in the first half of 2009. Predicted detectable viral load based on multivariate models, allowing for patient loss to follow up, also declined over time, but at higher levels, to 13.8% in 2009. Predicted detectable viral load in Australian HIV Observational Database patients receiving cART declined over calendar time, albeit at higher levels than observed. However, over this period, HIV diagnoses and estimated HIV incidence increased in Australia.

Cost of Illness of Multiple Sclerosis - A Systematic Review

PubMed Central

Ernstsson, Olivia; Gyllensten, Hanna; Alexanderson, Kristina; Tinghög, Petter; Friberg, Emilie; Norlund, Anders

2016-01-01

Background Cost-of-illness (COI) studies of Multiple Sclerosis (MS) are vital components for describing the economic burden of MS, and are frequently used in model studies of interventions of MS. We conducted a systematic review of studies estimating the COI of MS, to compare costs between studies and examine cost drivers, emphasizing generalizability and methodological choices. Material and method A literature search on studies published in English on COI of MS was performed in PubMed for the period January 1969 to January 2014, resulting in 1,326 publications. A mapping of studies using a bottom-up approach or top-down approach, respectively, was conducted for the 48 studies assessed as relevant. In a second analysis, the cost estimates were compared between the 29 studies that used a societal perspective on costs, human capital approach for indirect costs, presenting number of patients included, time-period studied, and year of price level used. Results The mapping showed that bottom-up studies and prevalence approaches were most common. The cost ratios between different severity levels within studies were relatively stable, to the ratio of 1 to 2 to 3 for disability level categories. Drugs were the main cost drivers for MS-patients with low disease severity, representing 29% to 82% of all costs in this patient group, while the main cost components for groups with more advanced MS symptoms were production losses due to MS and informal care, together representing 17% to 67% of costs in those groups. Conclusion The bottom-up method and prevalence approach dominated in studies of COI of MS. Our findings show that there are difficulties in comparing absolute costs across studies, nevertheless, the relative costs expressed as cost ratios, comparing different severity levels, showed higher resemblance. Costs of drugs were main cost drivers for less severe MS and informal care and production losses for the most severe MS. PMID:27411042

How to Assess Vulnerabilities of Water Policies to Global Change?

NASA Astrophysics Data System (ADS)

Kumar, A.; Haasnoot, M.; Weijs, S.

2017-12-01

Water managers are confronted with uncertainties arising from hydrological, societal, economical and political drivers. To manage these uncertainties two paradigms have been identified: top-down and bottom-up approaches. Top-down or prediction-based approaches use socio-economic scenarios together with a discrete set of GCM projections (often downscaled) to assess the expected impact of drivers and policies on water resource system through various hydrological and social systems models. Adaptation strategies to alleviate these impacts are then identified and tested against the scenarios. To address GCM and downscaling uncertainties, these approaches put more focus on climate predictions, rather than the decision problem itself. Triggered by the wish to have a more scenario-neutral approach and address downscaling uncertainties, recent analyses have been shifted towards vulnerability-based (bottom-up or decision-centric) approaches. They begin at the local scale by addressing socio-economic responses to climate, often involving stakeholder's input; identify vulnerabilities under a larger sample of plausible futures and evaluate sensitivity and robustness of possible adaptation options. Several bottom-up approaches have emerged so far and are increasingly recommended. Fundamentally they share several core ideas, however, subtle differences exist in vulnerability assessment, visualization tools for exploring vulnerabilities and computational methods used for identifying robust water policies. Through this study, we try to identify how these approaches are progressing, how the climate and non-climate uncertainties are being confronted and how to integrate existing and new tools. We find that choice of a method may depend on the number of vulnerability drivers identified and type of threshold levels (environmental conditions or policy objectives) defined. Certain approaches are suited well for assessing adaptive capacities, tipping points and sequencing of decisions. However, visualization of the vulnerability domain is still challenging if multiple drivers are present. New emerging tools are focused on generating synthetic scenarios, addressing multiple objectives, linking decision-making frameworks to adaptation pathways and communicating risks to the stakeholders.

Top-down and bottom-up approaches to greenhouse gas inventory methods—a comparison between national- and forest-scale reporting methods

Treesearch

David Nicholls; Frank Barnes; Felicia Acrea; Chinling Chen; Lara Y. Buluç; Michele M. Parker

2015-01-01

Federal agencies are mandated to measure, manage, and reduce greenhouse gas (GHG) emissions. The General Services Administration (GSA) Carbon Footprint Tool (CFT) is an online tool built to utilize measured GHG inventories to help Forest Service units streamline reporting and make informed decisions about operational efficiency. In fiscal year 2013, the Forest Service...

Systematic Review of Methods in Low-Consensus Fields: Supporting Commensuration through `Construct-Centered Methods Aggregation' in the Case of Climate Change Vulnerability Research.

PubMed

Delaney, Aogán; Tamás, Peter A; Crane, Todd A; Chesterman, Sabrina

2016-01-01

There is increasing interest in using systematic review to synthesize evidence on the social and environmental effects of and adaptations to climate change. Use of systematic review for evidence in this field is complicated by the heterogeneity of methods used and by uneven reporting. In order to facilitate synthesis of results and design of subsequent research a method, construct-centered methods aggregation, was designed to 1) provide a transparent, valid and reliable description of research methods, 2) support comparability of primary studies and 3) contribute to a shared empirical basis for improving research practice. Rather than taking research reports at face value, research designs are reviewed through inductive analysis. This involves bottom-up identification of constructs, definitions and operationalizations; assessment of concepts' commensurability through comparison of definitions; identification of theoretical frameworks through patterns of construct use; and integration of transparently reported and valid operationalizations into ideal-type research frameworks. Through the integration of reliable bottom-up inductive coding from operationalizations and top-down coding driven from stated theory with expert interpretation, construct-centered methods aggregation enabled both resolution of heterogeneity within identically named constructs and merging of differently labeled but identical constructs. These two processes allowed transparent, rigorous and contextually sensitive synthesis of the research presented in an uneven set of reports undertaken in a heterogenous field. If adopted more broadly, construct-centered methods aggregation may contribute to the emergence of a valid, empirically-grounded description of methods used in primary research. These descriptions may function as a set of expectations that improves the transparency of reporting and as an evolving comprehensive framework that supports both interpretation of existing and design of future research.

Systematic Review of Methods in Low-Consensus Fields: Supporting Commensuration through `Construct-Centered Methods Aggregation’ in the Case of Climate Change Vulnerability Research

PubMed Central

Crane, Todd A.; Chesterman, Sabrina

2016-01-01

There is increasing interest in using systematic review to synthesize evidence on the social and environmental effects of and adaptations to climate change. Use of systematic review for evidence in this field is complicated by the heterogeneity of methods used and by uneven reporting. In order to facilitate synthesis of results and design of subsequent research a method, construct-centered methods aggregation, was designed to 1) provide a transparent, valid and reliable description of research methods, 2) support comparability of primary studies and 3) contribute to a shared empirical basis for improving research practice. Rather than taking research reports at face value, research designs are reviewed through inductive analysis. This involves bottom-up identification of constructs, definitions and operationalizations; assessment of concepts’ commensurability through comparison of definitions; identification of theoretical frameworks through patterns of construct use; and integration of transparently reported and valid operationalizations into ideal-type research frameworks. Through the integration of reliable bottom-up inductive coding from operationalizations and top-down coding driven from stated theory with expert interpretation, construct-centered methods aggregation enabled both resolution of heterogeneity within identically named constructs and merging of differently labeled but identical constructs. These two processes allowed transparent, rigorous and contextually sensitive synthesis of the research presented in an uneven set of reports undertaken in a heterogenous field. If adopted more broadly, construct-centered methods aggregation may contribute to the emergence of a valid, empirically-grounded description of methods used in primary research. These descriptions may function as a set of expectations that improves the transparency of reporting and as an evolving comprehensive framework that supports both interpretation of existing and design of future research. PMID:26901409

Intelligent Evaluation Method of Tank Bottom Corrosion Status Based on Improved BP Artificial Neural Network

NASA Astrophysics Data System (ADS)

Qiu, Feng; Dai, Guang; Zhang, Ying

According to the acoustic emission information and the appearance inspection information of tank bottom online testing, the external factors associated with tank bottom corrosion status are confirmed. Applying artificial neural network intelligent evaluation method, three tank bottom corrosion status evaluation models based on appearance inspection information, acoustic emission information, and online testing information are established. Comparing with the result of acoustic emission online testing through the evaluation of test sample, the accuracy of the evaluation model based on online testing information is 94 %. The evaluation model can evaluate tank bottom corrosion accurately and realize acoustic emission online testing intelligent evaluation of tank bottom.

Outcomes of an HIV cohort after a decade of comprehensive care at Newlands Clinic in Harare, Zimbabwe: TENART cohort

PubMed Central

Chimbetete, Cleophas; Shawarira–Bote, Sandra; Luthy, Ruedi

2017-01-01

Background Data on long-term outcomes of patients receiving antiretroviral therapy (ART) in sub-Saharan Africa are few. We describe outcomes of patients commenced on ART at Newlands Clinic between 2004 and 2006 after ≥10 years of comprehensive care including, psychosocial, adherence and food support. Methods In this retrospective cohort study, patient data from an electronic medical record collected during routine care were analysed. We describe baseline characteristics, virological and clinical outcomes, attrition rates, and treatment adverse effects until November 2016. We defined virological suppression as viral load <50 copies/ml and virological failure as >1000 copies/ml after ≥6 months of ART. Results We analysed data for 605 patients (67% female) who commenced ART, and were followed-up for 5819 person-years (median: 10.7 years, IQR: 10.1–11.4). Median age at ART initiation was 34 years (IQR: 17–42). Pre-ART, 129 (21.3%) patients had history of pulmonary tuberculosis (PTB). In care, 66 (11%) developed PTB, and 24 (4%) developed extrapulmonary tuberculosis. 385 (63.6%) patients experienced ≥1 adverse event, the most frequent being stavudine-induced peripheral neuropathy (n = 252, 41.7%). At database closure on 14 November 2016, 474 (78.3%) patients were still in care, 428 (90.3%) being virologically suppressed, and 21 (4.4%) failing. While 483 (79.8%) remained on first line, 122 (20.2%) were switched to second line ART. Fifty-nine patients (9.8%) were transferred to other ART facilities, 45 (7.4%) were lost to follow-up, 25 (4.1%) died, and two stopped ART. Conclusion Comprehensive HIV care can result in low mortality, high retention in care and virologic suppression rates in resource limited settings. PMID:29065149

Mother-to-child transmission of HIV in a community-based antiretroviral clinic in South Africa

PubMed Central

Fitzgerald, Felicity C; Bekker, Linda-Gail; Kaplan, Richard; Myer, Landon; Lawn, Stephen D; Wood, Robin

2014-01-01

Objective To examine the uptake of ART among pregnant women referred to an ART service and the associated rates and risk factors for vertical HIV transmission. Method Retrospective analysis of an observational cohort at a community ART clinic in Cape Town. Results Between 2002 and 2008, 367 treatment-naïve pregnant women accessed the clinic. The median age was 27.5 years, and median gestation at presentation was 28 weeks. The median baseline CD4 count and viral load were 134 cells/µl and 28 282 copies/ml. Two hundred and sixty-five women (72%) commenced ART before giving birth, 73 women (20%) were referred for prevention of mother-to-child transmission therapy (PMTCT), and 29 (8%) received no intervention. Among ART-eligible women, 13% were lost to follow-up. Of those starting ART, median duration of therapy prior to birth was 7.6 weeks (interquartile range (IQR) 4 – 11.9). The HIV transmission rate was 5.1% (95% confidence interval (CI) 2.8 – 9.0%). Factors associated with transmission were advanced maternal WHO disease stage (odds ratio (OR) 9.57, p=0.02), and follow-up viral load above 50 copies/ml (OR 3.64, p=0.03). Each additional week on ART reduced transmission by 20% (p=0.05). There was no HIV transmission among women who received more than 8 weeks’ therapy. Conclusions The rate of HIV transmission in this study was higher than reported in high-income countries. Prevention of vertical transmission with ART was hindered by women presenting late in pregnancy and with advanced stage of HIV disease. Interventions that facilitate earlier ART commencement and improve programmatic retention of pregnant women are required. PMID:21414276

Rigorous evaluation of chemical measurement uncertainty: liquid chromatographic analysis methods using detector response factor calibration

NASA Astrophysics Data System (ADS)

Toman, Blaza; Nelson, Michael A.; Bedner, Mary

2017-06-01

Chemical measurement methods are designed to promote accurate knowledge of a measurand or system. As such, these methods often allow elicitation of latent sources of variability and correlation in experimental data. They typically implement measurement equations that support quantification of effects associated with calibration standards and other known or observed parametric variables. Additionally, multiple samples and calibrants are usually analyzed to assess accuracy of the measurement procedure and repeatability by the analyst. Thus, a realistic assessment of uncertainty for most chemical measurement methods is not purely bottom-up (based on the measurement equation) or top-down (based on the experimental design), but inherently contains elements of both. Confidence in results must be rigorously evaluated for the sources of variability in all of the bottom-up and top-down elements. This type of analysis presents unique challenges due to various statistical correlations among the outputs of measurement equations. One approach is to use a Bayesian hierarchical (BH) model which is intrinsically rigorous, thus making it a straightforward method for use with complex experimental designs, particularly when correlations among data are numerous and difficult to elucidate or explicitly quantify. In simpler cases, careful analysis using GUM Supplement 1 (MC) methods augmented with random effects meta analysis yields similar results to a full BH model analysis. In this article we describe both approaches to rigorous uncertainty evaluation using as examples measurements of 25-hydroxyvitamin D3 in solution reference materials via liquid chromatography with UV absorbance detection (LC-UV) and liquid chromatography mass spectrometric detection using isotope dilution (LC-IDMS).

Multilevel Hierarchical Kernel Spectral Clustering for Real-Life Large Scale Complex Networks

PubMed Central

Mall, Raghvendra; Langone, Rocco; Suykens, Johan A. K.

2014-01-01

Kernel spectral clustering corresponds to a weighted kernel principal component analysis problem in a constrained optimization framework. The primal formulation leads to an eigen-decomposition of a centered Laplacian matrix at the dual level. The dual formulation allows to build a model on a representative subgraph of the large scale network in the training phase and the model parameters are estimated in the validation stage. The KSC model has a powerful out-of-sample extension property which allows cluster affiliation for the unseen nodes of the big data network. In this paper we exploit the structure of the projections in the eigenspace during the validation stage to automatically determine a set of increasing distance thresholds. We use these distance thresholds in the test phase to obtain multiple levels of hierarchy for the large scale network. The hierarchical structure in the network is determined in a bottom-up fashion. We empirically showcase that real-world networks have multilevel hierarchical organization which cannot be detected efficiently by several state-of-the-art large scale hierarchical community detection techniques like the Louvain, OSLOM and Infomap methods. We show that a major advantage of our proposed approach is the ability to locate good quality clusters at both the finer and coarser levels of hierarchy using internal cluster quality metrics on 7 real-life networks. PMID:24949877

Differences in antiretroviral scale up in three South African provinces: the role of implementation management

PubMed Central

2010-01-01

Background South Africa’s antiretroviral programme is governed by defined national plans, establishing treatment targets and providing funding through ring-fenced conditional grants. However, in terms of the country’s quasi-federal constitution, provincial governments bear the main responsibility for provision of health care, and have a certain amount of autonomy and therefore choice in the way their HIV/AIDS programmes are implemented. Methods The paper is a comparative case study of the early management of ART scale up in three South African provincial governments – Western Cape, Gauteng and Free State – focusing on both operational and strategic dimensions. Drawing on surveys of models of ART care and analyses of the policy process conducted in the three provinces between 2005 and 2007, as well as a considerable body of grey and indexed literature on ART scale up in South Africa, it draws links between implementation processes and variations in provincial ART coverage (low, medium and high) achieved in the three provinces. Results While they adopted similar chronic disease care approaches, the provinces differed with respect to political and managerial leadership of the programme, programme design, the balance between central standardisation and local flexibility, the effectiveness of monitoring and evaluation systems, and the nature and extent of external support and programme partnerships. Conclusions This case study points to the importance of sub-national programme processes and the influence of factors other than financing or human resource capacity, in understanding intervention scale up. PMID:20594370

A retrospective cohort analysis comparing pregnancy rates among HIV-positive women using contraceptives and efavirenz- or nevirapine-based antiretroviral therapy in Kenya

PubMed Central

PATEL, Rena C.; ONONO, Maricianah; GANDHI, Monica; BLAT, Cinthia; HAGEY, Jill; SHADE, Starley B.; VITTINGHOFF, Eric; BUKUSI, Elizabeth A.; NEWMANN, Sara J.; COHEN, Craig R.

2015-01-01

SUMMARY Background Given recent concerns of efavirenz reducing the efficacy of contraceptive implants, we sought to determine if pregnancy rates differ among HIV-positive women using various contraceptive methods and efavirenz- or nevirapine-based antiretroviral therapy (ART) regimens. Methods We conducted a retrospective cohort analysis of HIV-positive women aged 15–45 years enrolled in HIV care facilities in western Kenya from January 2011 to December 2013. Pregnancy was diagnosed clinically and the primary exposure was a combination of contraceptive method and ART regimen. We used Poisson models, adjusting for repeated measures, as well as demographic, behavioral and clinical factors, to compare pregnancy rates among women on different contraceptive/ART combinations. Findings 24,560 women contributed 37,635 years of follow-up with 3,337 incident pregnancies. Among women using implants, adjusted pregnancy incidence for nevirapine- and efavirenz-based ART users were 1·1 (95% CI 0·72–1·5) and 3·3 (95% CI 1·8–4·8) per 100 women-years (w-y), respectively (adjusted incidence rate ratio (aIRR) 3·0, 95% CI 1·3–4·6). Among women using depomedroxyprogesterone acetate (DMPA), adjusted pregnancy incidence for nevirapine- and efavirenz-based ART users were 4·5 (95% CI 3·7–5·2) and 5·4 (95% CI 4·0–6·8) per 100 w-y, respectively (aIRR 1·2, 95% CI 0·91–1·5). Women using other contraceptive methods, except for intrauterine devices and permanent methods, experienced 3·1–4·1 higher rates of pregnancy than women using implants, with 1·6–2·8 higher rates specifically among women using efavirenz-based ART. Interpretation While HIV-positive women using implants on efavirenz-based ART faced three times higher risk of contraceptive failure than those on nevirapine-based ART, these women still experienced lower contraceptive failure rates than women on all other contraceptive methods, except for intrauterine devices and permanent methods. Guidelines for contraceptive and ART combinations should balance the failure rates for each contraceptive method and ART regimen combination against the high effectiveness of implants. Funding Supported by the President’s Emergency Plan for AIDS Relief and the Centers for Disease Control and Prevention. PMID:26520927

Neural correlates of context-dependent feature conjunction learning in visual search tasks.

PubMed

Reavis, Eric A; Frank, Sebastian M; Greenlee, Mark W; Tse, Peter U

2016-06-01

Many perceptual learning experiments show that repeated exposure to a basic visual feature such as a specific orientation or spatial frequency can modify perception of that feature, and that those perceptual changes are associated with changes in neural tuning early in visual processing. Such perceptual learning effects thus exert a bottom-up influence on subsequent stimulus processing, independent of task-demands or endogenous influences (e.g., volitional attention). However, it is unclear whether such bottom-up changes in perception can occur as more complex stimuli such as conjunctions of visual features are learned. It is not known whether changes in the efficiency with which people learn to process feature conjunctions in a task (e.g., visual search) reflect true bottom-up perceptual learning versus top-down, task-related learning (e.g., learning better control of endogenous attention). Here we show that feature conjunction learning in visual search leads to bottom-up changes in stimulus processing. First, using fMRI, we demonstrate that conjunction learning in visual search has a distinct neural signature: an increase in target-evoked activity relative to distractor-evoked activity (i.e., a relative increase in target salience). Second, we demonstrate that after learning, this neural signature is still evident even when participants passively view learned stimuli while performing an unrelated, attention-demanding task. This suggests that conjunction learning results in altered bottom-up perceptual processing of the learned conjunction stimuli (i.e., a perceptual change independent of the task). We further show that the acquired change in target-evoked activity is contextually dependent on the presence of distractors, suggesting that search array Gestalts are learned. Hum Brain Mapp 37:2319-2330, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Two-stage bottom-up tiered approach combining several alternatives for identification of eye irritation potential of chemicals including insoluble or volatile substances.

PubMed

Hayashi, Kazuhiko; Mori, Taeko; Abo, Takayuki; Ooshima, Kenichi; Hayashi, Takumi; Komano, Tomoko; Takahashi, Yutaka; Sakaguchi, Hitoshi; Takatsu, Akihiko; Nishiyama, Naohiro

2012-10-01

For the assessment of eye irritation, one alternative test may not completely replace the rabbit Draize test. In the present study, we examined the predictive potential of a tiered approach analyzing the results from several alternatives (i.e., the Short Time Exposure (STE) test, the EpiOcular assay, the Hen's Egg Test-Chorioallantoic Membrane (HET-CAM) assay and the Bovine Corneal Opacity and Permeability (BCOP) assay) for assessing Globally Harmonized System (GHS) eye irritation categories. Fifty-six chemicals including alcohols, surfactants, and esters were selected with a balanced GHS category and a wide range of chemical classes. From a standpoint of both assessable sample numbers and predictive accuracy, the more favorable tiered approach was considered to be the two-stage bottom-up tiered approach combining the STE test, the EpiOcular assay followed by the BCOP assay (accuracy 69.6%, under prediction rate 8.9%). Moreover, a more favorable predictive capacity (accuracy 71.4%, under prediction rate 3.6%) was obtained when high volatile alcohols/esters with vapor pressures >6 kilopascal (kPa) at 25°C were evaluated with EpiOcular assay instead of the STE test. From these results, the two-stage bottom-up tiered approach combining the STE test, the EpiOcular assay followed by the BCOP assay might be a promising method for the classification of GHS eye irritation category (Not classified (NC), Category 2 (Cat. 2), and Category 1 (Cat. 1)) for a wide range of test chemicals regardless of solubility. Copyright © 2012 Elsevier Ltd. All rights reserved.

Controlled Growth of Ceria Nanoarrays on Anatase Titania Powder: A Bottom-up Physical Picture.

PubMed

Kim, Hyun You; Hybertsen, Mark S; Liu, Ping

2017-01-11

The leading edge of catalysis research motivates physical understanding of the growth of nanoscale oxide structures on different supporting oxide materials that are themselves also nanostructured. This research opens up for consideration a diverse range of facets on the support material, versus the single facet typically involved in wide-area growth of thin films. Here, we study the growth of ceria nanoarchitectures on practical anatase titania powders as a showcase inspired by recent experiments. Density functional theory (DFT)-based methods are employed to characterize and rationalize the broad array of low energy nanostructures that emerge. Using a bottom-up approach, we are able to identify and characterize the underlying mechanisms for the facet-dependent growth of various ceria motifs on anatase titania based on formation energy. These motifs include 0D clusters, 1D chains, 2D plates, and 3D nanoparticles. The ceria growth mode and morphology are determined by the interplay of several factors including the role of the common cation valence, the interface template effect for different facets of the anatase support, enhanced ionic binding for more compact ceria motifs, and the local structural flexibility of oxygen ions in bridging the interface between anatase and ceria structures.

Search for scalar bottom quark pair production with the ATLAS detector in pp collisions at sqrt[s]=7  TeV.

PubMed

Aad, G; Abbott, B; Abdallah, J; Abdelalim, A A; Abdesselam, A; Abdinov, O; Abi, B; Abolins, M; AbouZeid, O S; Abramowicz, H; Abreu, H; Acerbi, E; Acharya, B S; Adamczyk, L; Adams, D L; Addy, T N; Adelman, J; Aderholz, M; Adomeit, S; Adragna, P; Adye, T; Aefsky, S; Aguilar-Saavedra, J A; Aharrouche, M; Ahlen, S P; Ahles, F; Ahmad, A; Ahsan, M; Aielli, G; Akdogan, T; Åkesson, T P A; Akimoto, G; Akimov, A V; Akiyama, A; Alam, M S; Alam, M A; Albert, J; Albrand, S; Aleksa, M; Aleksandrov, I N; Alessandria, F; Alexa, C; Alexander, G; Alexandre, G; Alexopoulos, T; Alhroob, M; Aliev, M; Alimonti, G; Alison, J; Aliyev, M; Allport, P P; Allwood-Spiers, S E; Almond, J; Aloisio, A; Alon, R; Alonso, A; Alvarez Gonzalez, B; Alviggi, M G; Amako, K; Amaral, P; Amelung, C; Ammosov, V V; Amorim, A; Amorós, G; Amram, N; Anastopoulos, C; Ancu, L S; Andari, N; Andeen, T; Anders, C F; Anders, G; Anderson, K J; Andreazza, A; Andrei, V; Andrieux, M-L; Anduaga, X S; Angerami, A; Anghinolfi, F; Anisenkov, A; Anjos, N; Annovi, A; Antonaki, A; Antonelli, M; Antonov, A; Antos, J; Anulli, F; Aoun, S; Aperio Bella, L; Apolle, R; Arabidze, G; Aracena, I; Arai, Y; Arce, A T H; Archambault, J P; Arfaoui, S; Arguin, J-F; Arik, E; Arik, M; Armbruster, A J; Arnaez, O; Arnault, C; Artamonov, A; Artoni, G; Arutinov, D; Asai, S; Asfandiyarov, R; Ask, S; Åsman, B; Asquith, L; Assamagan, K; Astbury, A; Astvatsatourov, A; Aubert, B; Auge, E; Augsten, K; Aurousseau, M; Avolio, G; Avramidou, R; Axen, D; Ay, C; Azuelos, G; Azuma, Y; Baak, M A; Baccaglioni, G; Bacci, C; Bach, A M; Bachacou, H; Bachas, K; Bachy, G; Backes, M; Backhaus, M; Badescu, E; Bagnaia, P; Bahinipati, S; Bai, Y; Bailey, D C; Bain, T; Baines, J T; Baker, O K; Baker, M D; Baker, S; Banas, E; Banerjee, P; Banerjee, Sw; Banfi, D; Bangert, A; Bansal, V; Bansil, H S; Barak, L; Baranov, S P; Barashkou, A; Barbaro Galtieri, A; Barber, T; Barberio, E L; Barberis, D; Barbero, M; Bardin, D Y; Barillari, T; Barisonzi, M; Barklow, T; Barlow, N; Barnett, B M; Barnett, R M; Baroncelli, A; Barone, G; Barr, A J; Barreiro, F; Barreiro Guimarães da Costa, J; Barrillon, P; Bartoldus, R; Barton, A E; Bartsch, V; Bates, R L; Batkova, L; Batley, J R; Battaglia, A; Battistin, M; Bauer, F; Bawa, H S; Beale, S; Beare, B; Beau, T; Beauchemin, P H; Beccherle, R; Bechtle, P; Beck, H P; Becker, S; Beckingham, M; Becks, K H; Beddall, A J; Beddall, A; Bedikian, S; Bednyakov, V A; Bee, C P; Begel, M; Behar Harpaz, S; Behera, P K; Beimforde, M; Belanger-Champagne, C; Bell, P J; Bell, W H; Bella, G; Bellagamba, L; Bellina, F; Bellomo, M; Belloni, A; Beloborodova, O; Belotskiy, K; Beltramello, O; Ben Ami, S; Benary, O; Benchekroun, D; Benchouk, C; Bendel, M; Benekos, N; Benhammou, Y; Benhar Noccioli, E; Benitez Garcia, J A; Benjamin, D P; Benoit, M; Bensinger, J R; Benslama, K; Bentvelsen, S; Berge, D; Bergeaas Kuutmann, E; Berger, N; Berghaus, F; Berglund, E; Beringer, J; Bernat, P; Bernhard, R; Bernius, C; Berry, T; Bertella, C; Bertin, A; Bertinelli, F; Bertolucci, F; Besana, M I; Besson, N; Bethke, S; Bhimji, W; Bianchi, R M; Bianco, M; Biebel, O; Bieniek, S P; Bierwagen, K; Biesiada, J; Biglietti, M; Bilokon, H; Bindi, M; Binet, S; Bingul, A; Bini, C; Biscarat, C; Bitenc, U; Black, K M; Blair, R E; Blanchard, J-B; Blanchot, G; Blazek, T; Blocker, C; Blocki, J; Blondel, A; Blum, W; Blumenschein, U; Bobbink, G J; Bobrovnikov, V B; Bocchetta, S S; Bocci, A; Boddy, C R; Boehler, M; Boek, J; Boelaert, N; Böser, S; Bogaerts, J A; Bogdanchikov, A; Bogouch, A; Bohm, C; Boisvert, V; Bold, T; Boldea, V; Bolnet, N M; Bona, M; Bondarenko, V G; Bondioli, M; Boonekamp, M; Boorman, G; Booth, C N; Bordoni, S; Borer, C; Borisov, A; Borissov, G; Borjanovic, I; Borroni, S; Bos, K; Boscherini, D; Bosman, M; Boterenbrood, H; Botterill, D; Bouchami, J; Boudreau, J; Bouhova-Thacker, E V; Boumediene, D; Bourdarios, C; Bousson, N; Boveia, A; Boyd, J; Boyko, I R; Bozhko, N I; Bozovic-Jelisavcic, I; Bracinik, J; Braem, A; Branchini, P; Brandenburg, G W; Brandt, A; Brandt, G; Brandt, O; 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Wall, R; Waller, P; Wang, C; Wang, H; Wang, H; Wang, J; Wang, J; Wang, J C; Wang, R; Wang, S M; Warburton, A; Ward, C P; Warsinsky, M; Watkins, P M; Watson, A T; Watson, I J; Watson, M F; Watts, G; Watts, S; Waugh, A T; Waugh, B M; Weber, M; Weber, M S; Weber, P; Weidberg, A R; Weigell, P; Weingarten, J; Weiser, C; Wellenstein, H; Wells, P S; Wen, M; Wenaus, T; Wendler, S; Weng, Z; Wengler, T; Wenig, S; Wermes, N; Werner, M; Werner, P; Werth, M; Wessels, M; Weydert, C; Whalen, K; Wheeler-Ellis, S J; Whitaker, S P; White, A; White, M J; Whitehead, S R; Whiteson, D; Whittington, D; Wicek, F; Wicke, D; Wickens, F J; Wiedenmann, W; Wielers, M; Wienemann, P; Wiglesworth, C; Wiik-Fuchs, L A M; Wijeratne, P A; Wildauer, A; Wildt, M A; Wilhelm, I; Wilkens, H G; Will, J Z; Williams, E; Williams, H H; Willis, W; Willocq, S; Wilson, J A; Wilson, M G; Wilson, A; Wingerter-Seez, I; Winkelmann, S; Winklmeier, F; Wittgen, M; Wolter, M W; Wolters, H; Wong, W C; Wooden, G; Wosiek, B K; Wotschack, J; Woudstra, M J; Wozniak, K W; Wraight, K; Wright, C; Wright, M; Wrona, B; Wu, S L; Wu, X; Wu, Y; Wulf, E; Wunstorf, R; Wynne, B M; Xella, S; Xiao, M; Xie, S; Xie, Y; Xu, C; Xu, D; Xu, G; Yabsley, B; Yacoob, S; Yamada, M; Yamaguchi, H; Yamamoto, A; Yamamoto, K; Yamamoto, S; Yamamura, T; Yamanaka, T; Yamaoka, J; Yamazaki, T; Yamazaki, Y; Yan, Z; Yang, H; Yang, U K; Yang, Y; Yang, Y; Yang, Z; Yanush, S; Yao, Y; Yasu, Y; Ybeles Smit, G V; Ye, J; Ye, S; Yilmaz, M; Yoosoofmiya, R; Yorita, K; Yoshida, R; Young, C; Youssef, S; Yu, D; Yu, J; Yu, J; Yuan, L; Yurkewicz, A; Zabinski, B; Zaets, V G; Zaidan, R; Zaitsev, A M; Zajacova, Z; Zanello, L; Zarzhitsky, P; Zaytsev, A; Zeitnitz, C; Zeller, M; Zeman, M; Zemla, A; Zendler, C; Zenin, O; Ženiš, T; Zinonos, Z; Zenz, S; Zerwas, D; Zevi della Porta, G; Zhan, Z; Zhang, D; Zhang, H; Zhang, J; Zhang, X; Zhang, Z; Zhao, L; Zhao, T; Zhao, Z; Zhemchugov, A; Zheng, S; Zhong, J; Zhou, B; Zhou, N; Zhou, Y; Zhu, C G; Zhu, H; Zhu, J; Zhu, Y; Zhuang, X; Zhuravlov, V; Zieminska, D; Zimmermann, R; Zimmermann, S; Zimmermann, S; Ziolkowski, M; Zitoun, R; Živković, L; Zmouchko, V V; Zobernig, G; Zoccoli, A; Zolnierowski, Y; Zsenei, A; zur Nedden, M; Zutshi, V; Zwalinski, L

2012-05-04

The results of a search for pair production of the scalar partners of bottom quarks in 2.05  fb(-1) of pp collisions at sqrt[s]=7  TeV using the ATLAS experiment are reported. Scalar bottom quarks are searched for in events with large missing transverse momentum and two jets in the final state, where both jets are identified as originating from a bottom quark. In an R-parity conserving minimal supersymmetric scenario, assuming that the scalar bottom quark decays exclusively into a bottom quark and a neutralino, 95% confidence-level upper limits are obtained in the b(1) - χ(1)(0) mass plane such that for neutralino masses below 60 GeV scalar bottom masses up to 390 GeV are excluded.

When to Start Antiretroviral Therapy in Children Aged 2–5 Years: A Collaborative Causal Modelling Analysis of Cohort Studies from Southern Africa

PubMed Central

Schomaker, Michael; Egger, Matthias; Ndirangu, James; Phiri, Sam; Moultrie, Harry; Technau, Karl; Cox, Vivian; Giddy, Janet; Chimbetete, Cleophas; Wood, Robin; Gsponer, Thomas; Bolton Moore, Carolyn; Rabie, Helena; Eley, Brian; Muhe, Lulu; Penazzato, Martina; Essajee, Shaffiq; Keiser, Olivia; Davies, Mary-Ann

2013-01-01

Background There is limited evidence on the optimal timing of antiretroviral therapy (ART) initiation in children 2–5 y of age. We conducted a causal modelling analysis using the International Epidemiologic Databases to Evaluate AIDS–Southern Africa (IeDEA-SA) collaborative dataset to determine the difference in mortality when starting ART in children aged 2–5 y immediately (irrespective of CD4 criteria), as recommended in the World Health Organization (WHO) 2013 guidelines, compared to deferring to lower CD4 thresholds, for example, the WHO 2010 recommended threshold of CD4 count <750 cells/mm3 or CD4 percentage (CD4%) <25%. Methods and Findings ART-naïve children enrolling in HIV care at IeDEA-SA sites who were between 24 and 59 mo of age at first visit and with ≥1 visit prior to ART initiation and ≥1 follow-up visit were included. We estimated mortality for ART initiation at different CD4 thresholds for up to 3 y using g-computation, adjusting for measured time-dependent confounding of CD4 percent, CD4 count, and weight-for-age z-score. Confidence intervals were constructed using bootstrapping. The median (first; third quartile) age at first visit of 2,934 children (51% male) included in the analysis was 3.3 y (2.6; 4.1), with a median (first; third quartile) CD4 count of 592 cells/mm3 (356; 895) and median (first; third quartile) CD4% of 16% (10%; 23%). The estimated cumulative mortality after 3 y for ART initiation at different CD4 thresholds ranged from 3.4% (95% CI: 2.1–6.5) (no ART) to 2.1% (95% CI: 1.3%–3.5%) (ART irrespective of CD4 value). Estimated mortality was overall higher when initiating ART at lower CD4 values or not at all. There was no mortality difference between starting ART immediately, irrespective of CD4 value, and ART initiation at the WHO 2010 recommended threshold of CD4 count <750 cells/mm3 or CD4% <25%, with mortality estimates of 2.1% (95% CI: 1.3%–3.5%) and 2.2% (95% CI: 1.4%–3.5%) after 3 y, respectively. The analysis was limited by loss to follow-up and the unavailability of WHO staging data. Conclusions The results indicate no mortality difference for up to 3 y between ART initiation irrespective of CD4 value and ART initiation at a threshold of CD4 count <750 cells/mm3 or CD4% <25%, but there are overall higher point estimates for mortality when ART is initiated at lower CD4 values. Please see later in the article for the Editors' Summary PMID:24260029

Retention in pre-antiretroviral treatment care in a district of Karnataka, India: how well are we doing?

PubMed Central

Kumar, A. M. V.; Rewari, B.; Kumar, S.; Shastri, S.; Satyanarayana, S.; Ananthakrishnan, R.; Nagaraja, S. B.; Devi, M.; Bhargava, N.; Das, M.; Zachariah, R.

2014-01-01

Setting: Antiretroviral treatment (ART) Centre in Tumkur district of Karnataka State, India. There is no published information about pre-ART loss to follow-up from India. Objective: To assess the proportion lost to follow-up (defined as not visiting the ART Centre within 1 year of registration) and associated socio-demographic and immunological variables. Design: Retrospective cohort study involving a review of medical records of adult HIV-infected persons (aged ⩾15 years) registered in pre-ART care during January 2010–June 2012. Results: Of 3238 patients registered, 2519 (78%) were eligible for ART, while 719 (22%) were not. Four of the latter were transferred out; the remaining 715 individuals were enrolled in pre-ART care, of whom 290 (41%) were lost to follow-up. Factors associated with loss to follow-up on multivariate analysis included age group ⩾45 years, low educational level, not being married, World Health Organization Stage III or IV and rural residence. Conclusion: About four in 10 individuals in pre-ART care were lost to follow-up within 1 year of registration. This needs urgent attention. Routine cohort analysis in the national programme should include those in pre-ART care to enable improved review, monitoring and supervision. Further qualitative research to ascertain reasons for loss to follow-up is required to design future interventions. PMID:26400698

Predictors of loss to follow-up among children in the first and second years of antiretroviral treatment in Johannesburg, South Africa

PubMed Central

Sengayi, Mazvita; Dwane, Ntabozuko; Marinda, Edmore; Sipambo, Nosisa; Fairlie, Lee; Moultrie, Harry

2013-01-01

Background Ninety percent of the world's 2.1 million HIV-infected children live in sub-Saharan Africa, and 2.5% of South African children live with HIV. As HIV care and treatment programmes are scaled-up, a rise in loss to follow-up (LTFU) has been observed. Objective The aim of the study was to determine the rate of LTFU in children receiving antiretroviral treatment (ART) and to identify baseline characteristics associated with LTFU in the first year of treatment. We also explored the effect of patient characteristics at 12 months treatment on LTFU in the second year. Methods The study is an analysis of prospectively collected routine data of HIV-infected children at the Harriet Shezi Children's Clinic (HSCC) in Soweto, Johannesburg. Cox proportional hazards models were fitted to investigate associations between baseline characteristics and 12-month characteristics with LTFU in the first and second year on ART, respectively. Results The cumulative probability of LTFU at 12 months was 7.3% (95% CI 7.1–8.8). In the first 12 months on ART, independent predictors of LTFU were age <1 year at initiation, recent year of ART start, mother as a primary caregiver, and being underweight (WAZ ≤ −2). Among children still on treatment at 1 year from ART initiation, characteristics that predicted LTFU within the second year were recent year of ART start, mother as a primary caregiver, being underweight (WAZ ≤ −2), and low CD4 cell percentage. Conclusions There are similarities between the known predictors of death and the predictors of LTFU in the first and second years of ART. Knowing the vital status of children is important to determine LTFU. Although HIV-positive children cared for by their mothers appear to be at greater risk of becoming LTFU, further research is needed to explore the challenges faced by mothers and other caregivers and their impact on long-term HIV care. There is also a need to investigate the effects of differential access to ART between mothers and children and its impact on ART outcomes in children. PMID:23364098

Dependency-based long short term memory network for drug-drug interaction extraction.

PubMed

Wang, Wei; Yang, Xi; Yang, Canqun; Guo, Xiaowei; Zhang, Xiang; Wu, Chengkun

2017-12-28

Drug-drug interaction extraction (DDI) needs assistance from automated methods to address the explosively increasing biomedical texts. In recent years, deep neural network based models have been developed to address such needs and they have made significant progress in relation identification. We propose a dependency-based deep neural network model for DDI extraction. By introducing the dependency-based technique to a bi-directional long short term memory network (Bi-LSTM), we build three channels, namely, Linear channel, DFS channel and BFS channel. All of these channels are constructed with three network layers, including embedding layer, LSTM layer and max pooling layer from bottom up. In the embedding layer, we extract two types of features, one is distance-based feature and another is dependency-based feature. In the LSTM layer, a Bi-LSTM is instituted in each channel to better capture relation information. Then max pooling is used to get optimal features from the entire encoding sequential data. At last, we concatenate the outputs of all channels and then link it to the softmax layer for relation identification. To the best of our knowledge, our model achieves new state-of-the-art performance with the F-score of 72.0% on the DDIExtraction 2013 corpus. Moreover, our approach obtains much higher Recall value compared to the existing methods. The dependency-based Bi-LSTM model can learn effective relation information with less feature engineering in the task of DDI extraction. Besides, the experimental results show that our model excels at balancing the Precision and Recall values.

Systems Bioinformatics: increasing precision of computational diagnostics and therapeutics through network-based approaches.

PubMed

Oulas, Anastasis; Minadakis, George; Zachariou, Margarita; Sokratous, Kleitos; Bourdakou, Marilena M; Spyrou, George M

2017-11-27

Systems Bioinformatics is a relatively new approach, which lies in the intersection of systems biology and classical bioinformatics. It focuses on integrating information across different levels using a bottom-up approach as in systems biology with a data-driven top-down approach as in bioinformatics. The advent of omics technologies has provided the stepping-stone for the emergence of Systems Bioinformatics. These technologies provide a spectrum of information ranging from genomics, transcriptomics and proteomics to epigenomics, pharmacogenomics, metagenomics and metabolomics. Systems Bioinformatics is the framework in which systems approaches are applied to such data, setting the level of resolution as well as the boundary of the system of interest and studying the emerging properties of the system as a whole rather than the sum of the properties derived from the system's individual components. A key approach in Systems Bioinformatics is the construction of multiple networks representing each level of the omics spectrum and their integration in a layered network that exchanges information within and between layers. Here, we provide evidence on how Systems Bioinformatics enhances computational therapeutics and diagnostics, hence paving the way to precision medicine. The aim of this review is to familiarize the reader with the emerging field of Systems Bioinformatics and to provide a comprehensive overview of its current state-of-the-art methods and technologies. Moreover, we provide examples of success stories and case studies that utilize such methods and tools to significantly advance research in the fields of systems biology and systems medicine. © The Author 2017. Published by Oxford University Press.

Fire and climate variation in western North America from fire-scar and tree-ring networks

Treesearch

Donald A. Falk; E. K. Heyerdahl; P. M. Brown; T. W. Swetnam; E. K. Sutherland; Z. Gedalof; L. Yocom; T. J. Brown

2010-01-01

Fire regimes (i.e., the pattern, frequency and intensity of fire in a region) reflect a complex interplay of bottom-up and top-down controls (Lertzman et al., 1998; Mc Kenzie et al., in press). Bottom-up controls include local variations in topographic, fuel and weather factors at the time of a burn (e.g., fuel moisture and continuity, ignition density and local wind...

Subjective Well-Being: The Constructionist Point of View. A Longitudinal Study to Verify the Predictive Power of Top-Down Effects and Bottom-Up Processes

ERIC Educational Resources Information Center

Leonardi, Fabio; Spazzafumo, Liana; Marcellini, Fiorella

2005-01-01

Based on the constructionist point of view applied to Subjective Well-Being (SWB), five hypotheses were advanced about the predictive power of the top-down effects and bottom-up processes over a five years period. The sample consisted of 297 respondents, which represent the Italian sample of a European longitudinal survey; the first phase was…

The impact of a private-public partnership delivery system on the HIV continuum of care in a South Indian city.

PubMed

Waldrop, Greer; Sarvode, Suraj; Rao, Srirama; Swamy, V H T; Solomon, Sunil Suhas; Mehta, Shruti H; Mothi, S N

2018-03-01

We characterized the impact of a Private-Public Partnership (PPP) on the continuum of HIV care (e.g., treatment initiation, ART effectiveness and loss to follow-up) among adults enrolled at a private hospital/ART link center in the southern state of Karnataka, India from 2007 through 2012. Data on 2326 adults in care were compiled using an electronic database supplemented with medical chart abstraction. Survival methods with staggered entries were used to analyze time to ART initiation and loss to follow-up as well as associated factors. Mixed effects linear regression models were used to assess ART effectiveness. The mean age of adults in care was 36 years; 40% were male. The majority were married, had less than primary education, and less than 45 US dollars (3000 Indian Rupee) monthly income. The mean CD4 at presentation was 527 cells/mm 3 . The median time from ART eligibility to initiation was 5 and 2 months for before and after the PPP, respectively (p < 0.001). Becoming eligible after PPP was associated with more rapid treatment initiation (Hazard Ratio: [95% Confidence Interval] 1.49 [1.11, 1.99]). Moreover, among the 1639 persons lost to follow-up, more rapid loss was observed before the PPP (12.77 months) vs. after (13.37 months) (p = 0.25) and there was a significant interaction between ART status and calendar time before and after the PPP (p < 0.001). Being on treatment was associated with a lower likelihood of becoming lost before the PPP (HR: [95% CI] 0.33 [0.27, 0.42]), but this association was reversed after the PPP (HR: [95% CI] 1.77 [1.54, 2.04]), p-value for interaction <0.001. Treatment response measured by CD4 was comparable before and after the PPP (p = 0.088). Our findings suggest that PPP models of ART delivery may improve HIV treatment initiation and loss to follow-up without compromising the effectiveness of treatment. Efforts to expand these system-level interventions should be considered with on-going evaluation.

Great expectations: top-down attention modulates the costs of clutter and eccentricity.

PubMed

Steelman, Kelly S; McCarley, Jason S; Wickens, Christopher D

2013-12-01

An experiment and modeling effort examined interactions between bottom-up and top-down attentional control in visual alert detection. Participants performed a manual tracking task while monitoring peripheral display channels for alerts of varying salience, eccentricity, and spatial expectancy. Spatial expectancy modulated the influence of salience and eccentricity; alerts in low-probability locations engendered higher miss rates, longer detection times, and larger costs of visual clutter and eccentricity, indicating that top-down attentional control offset the costs of poor bottom-up stimulus quality. Data were compared to the predictions of a computational model of scanning and noticing that incorporates bottom-up and top-down sources of attentional control. The model accounted well for the overall pattern of miss rates and response times, predicting each of the observed main effects and interactions. Empirical results suggest that designers should expect the costs of poor bottom-up visibility to be greater for low expectancy signals, and that the placement of alerts within a display should be determined based on the combination of alert expectancy and response priority. Model fits suggest that the current model can serve as a useful tool for exploring a design space as a precursor to empirical data collection and for generating hypotheses for future experiments. PsycINFO Database Record (c) 2013 APA, all rights reserved.

Saccade Generation by the Frontal Eye Fields in Rhesus Monkeys Is Separable from Visual Detection and Bottom-Up Attention Shift

PubMed Central

Lee, Kyoung-Min; Ahn, Kyung-Ha; Keller, Edward L.

2012-01-01

The frontal eye fields (FEF), originally identified as an oculomotor cortex, have also been implicated in perceptual functions, such as constructing a visual saliency map and shifting visual attention. Further dissecting the area’s role in the transformation from visual input to oculomotor command has been difficult because of spatial confounding between stimuli and responses and consequently between intermediate cognitive processes, such as attention shift and saccade preparation. Here we developed two tasks in which the visual stimulus and the saccade response were dissociated in space (the extended memory-guided saccade task), and bottom-up attention shift and saccade target selection were independent (the four-alternative delayed saccade task). Reversible inactivation of the FEF in rhesus monkeys disrupted, as expected, contralateral memory-guided saccades, but visual detection was demonstrated to be intact at the same field. Moreover, saccade behavior was impaired when a bottom-up shift of attention was not a prerequisite for saccade target selection, indicating that the inactivation effect was independent of the previously reported dysfunctions in bottom-up attention control. These findings underscore the motor aspect of the area’s functions, especially in situations where saccades are generated by internal cognitive processes, including visual short-term memory and long-term associative memory. PMID:22761923

Saccade generation by the frontal eye fields in rhesus monkeys is separable from visual detection and bottom-up attention shift.

PubMed

Lee, Kyoung-Min; Ahn, Kyung-Ha; Keller, Edward L

2012-01-01

The frontal eye fields (FEF), originally identified as an oculomotor cortex, have also been implicated in perceptual functions, such as constructing a visual saliency map and shifting visual attention. Further dissecting the area's role in the transformation from visual input to oculomotor command has been difficult because of spatial confounding between stimuli and responses and consequently between intermediate cognitive processes, such as attention shift and saccade preparation. Here we developed two tasks in which the visual stimulus and the saccade response were dissociated in space (the extended memory-guided saccade task), and bottom-up attention shift and saccade target selection were independent (the four-alternative delayed saccade task). Reversible inactivation of the FEF in rhesus monkeys disrupted, as expected, contralateral memory-guided saccades, but visual detection was demonstrated to be intact at the same field. Moreover, saccade behavior was impaired when a bottom-up shift of attention was not a prerequisite for saccade target selection, indicating that the inactivation effect was independent of the previously reported dysfunctions in bottom-up attention control. These findings underscore the motor aspect of the area's functions, especially in situations where saccades are generated by internal cognitive processes, including visual short-term memory and long-term associative memory.

Theory-driven intervention for changing personality: expectancy value theory, behavioral activation, and conscientiousness.

PubMed

Magidson, Jessica F; Roberts, Brent W; Collado-Rodriguez, Anahi; Lejuez, C W

2014-05-01

Considerable evidence suggests that personality traits may be changeable, raising the possibility that personality traits most linked to health problems can be modified with intervention. A growing body of research suggests that problematic personality traits may be altered with behavioral intervention using a bottom-up approach. That is, by targeting core behaviors that underlie personality traits with the goal of engendering new, healthier patterns of behavior that, over time, become automatized and manifest in changes in personality traits. Nevertheless, a bottom-up model for changing personality traits is somewhat diffuse and requires clearer integration of theory and relevant interventions to enable real clinical application. As such, this article proposes a set of guiding principles for theory-driven modification of targeted personality traits using a bottom-up approach, focusing specifically on targeting the trait of conscientiousness using a relevant behavioral intervention, Behavioral Activation (BA), considered within the motivational framework of expectancy value theory (EVT). We conclude with a real case example of the application of BA to alter behaviors counter to conscientiousness in a substance-dependent patient, highlighting the EVT principles most relevant to the approach and the importance and viability of a theoretically driven, bottom-up approach to changing personality traits. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

Changes in Fertility at the Population Level in the Era of ART in Rural Malawi

PubMed Central

Price, Alison; Chihana, Menard; Kayuni, Ndoliwe; Marston, Milly; Koole, Olivier; Zaba, Basia; Crampin, Amelia

2017-01-01

Introduction: HIV reduces fertility through biological and social pathways, and antiretroviral treatment (ART) can ameliorate these effects. In northern Malawi, ART has been available since 2007 and lifelong ART is offered to all pregnant or breastfeeding HIV-positive women. Methods: Using data from the Karonga Health and Demographic Surveillance Site in Malawi from 2005 to 2014, we used total and age-specific fertility rates and Cox regression to assess associations between HIV and ART use and fertility. We also assessed temporal trends in in utero and breastfeeding HIV and ART exposure among live births. Results: From 2005 to 2014, there were 13,583 live births during approximately 78,000 person years of follow-up of women aged 15–49 years. The total fertility rate in HIV-negative women decreased from 6.1 [95% confidence interval (CI): 5.5 to 6.8] in 2005–2006 to 5.1 (4.8–5.5) in 2011–2014. In HIV-positive women, the total fertility rate was more stable, although lower, at 4.4 (3.2–6.1) in 2011–2014. In 2011–2014, compared with HIV-negative women, the adjusted (age, marital status, and education) hazard ratio was 0.7 (95% CI: 0.6 to 0.9) and 0.8 (95% CI: 0.6 to 1.0) for women on ART for at least 9 months and not (yet) on ART, respectively. The crude fertility rate increased with duration on ART up to 3 years before declining. The proportion of HIV-exposed infants decreased, but the proportion of ART-exposed infants increased from 2.4% in 2007–2010 to 3.5% in 2011–2014. Conclusions: Fertility rates in HIV-positive women are stable in the context of generally decreasing fertility. Despite a decrease in HIV-exposed infants, there has been an increase in ART-exposed infants. PMID:28653969

Regulation, consultation and divergent community views: the case of access to ART by lesbian and single women.

PubMed

Cannold, Leslie; Gillam, Lynn

2002-05-01

In the many countries which have some form of regulation of ART, a public consultation of some sort is a frequent feature of either the process leading up to regulation or of the regulatory mechanism itself. Not surprisingly, widely divergent views on the moral and political acceptability of ART are expressed during such consultations. And while such diversity of opinion is to be expected, and some even argue welcomed, in pluralist liberal democratic societies, it is often unclear how these divergent community views are and ought to be fed into the opinion-forming and decision-making processes of governments or the bodies that advise them. This article discusses first why regulation of ART may be justified, even when there is radical moral disagreement in the community, and why public consultations should play a central role in the work that advisory bodies undertake in making regulatory recommendations to government. Then, it both proposes and justifies a method for dealing with the contradictory moral views expressed by interested parties during the consultation process. To illustrate this method, the example of the attempt by single and lesbian women to access donor insemination services and ART is used.

[Characteristics of art therapists in rehabilitative therapy].

PubMed

Oster, Jörg

2017-09-01

Characteristics of art therapists in rehabilitative therapy Objectives: This study examines the sociodemographic, qualification- and activity-related characteristics of art therapists working in the field of rehabilitation. In 2013, an analysis of occupational groups was carried out in Germany, with the objective of describing the art therapists working there.A total of 2,303 complete datasets were submitted. From this group, those therapists mainly working in the field of rehabilitation/follow-up care/participation of disabled persons (according to Social Security Code VI and IX, n = 302) were selected and described. Most art therapists are female (average age 45 years) and largelywork part-time. Music and art therapy are the most common venues.More than 80% have a graduate degree. Methods of quality management are used.More than half of the therapists working in rehabilitation hospitals are employed in the field of psychosomatic medicine. Both individual and group therapy (each patient attending 1-2 times a week) are common. The results provide an overview of art therapy in the field of rehabilitation and show the spread in rehabilitation. Further research is indicated.

Merging bottom-up and top-down precipitation products using a stochastic error model

NASA Astrophysics Data System (ADS)

Maggioni, Viviana; Massari, Christian; Brocca, Luca; Ciabatta, Luca

2017-04-01

Accurate quantitative precipitation estimation is of great importance for water resources management, agricultural planning, and forecasting and monitoring of natural hazards such as flash floods and landslides. In situ observations are limited around the Earth, especially in remote areas (e.g., complex terrain, dense vegetation), but currently available satellite precipitation products are able to provide global precipitation estimates with an accuracy that depends upon many factors (e.g., type of storms, temporal sampling, season etc…). Recently, Brocca et al. (2014) have proposed an alternative approach (i.e., SM2RAIN) that allows to estimate rainfall from space by using satellite soil moisture observations. In contrast with classical satellite precipitation products which sense the cloud properties to retrieve the instantaneous precipitation, this new bottom-up approach makes use of two consecutive soil moisture measurements for obtaining an estimate of the fallen precipitation within the interval between two satellite passes. As a result, the nature of the measurement is different and complementary to the one of classical precipitation products and could provide a different valid perspective to improve current satellite rainfall estimates via appropriate integration between the products (i.e., SM2RAIN plus a classical satellite rainfall product). However, whether SM2RAIN is able or not to improve the performance of any state-of-the-art satellite rainfall product is much dependent upon an adequate quantification and characterization of the relative errors of the products. In this study, the stochastic rainfall error model SREM2D (Hossain et al. 2006) is used for characterizing the retrieval error of both SM2RAIN and a state-of-the-art satellite precipitation product (i.e., 3B42RT). The error characterization serves for an optimal integration between SM2RAIN and 3B42RT for enhancing the capability of the resulting integrated product (i.e. SM2RAIN+3B42RT) in operational hydrology. The study, conducted in Italy for a 5-yr period (2010-2014) using a dense network of raingauges (about 3000) as a benchmark, demonstrates that the integration is able to enhance the correlation and the root mean squared error of SM2RAIN+3B42RT with respect to the parent products. This suggests a potential benefit of merging SM2RAIN derived rainfall with state-of-the-art satellite precipitation estimates for creating a product characterized by higher accuracy and better performance when used in the contest of operational hydrology. REFERENCES 1. Brocca, L.; Ciabatta, L.; Massari, C.; Moramarco, T.; Hahn, S.; Hasenauer, S.; Kidd, R.; Dorigo, W.; Wagner, W.; Levizzani, V. Soil as a natural rain gauge: Estimating global rainfall from satellite soil moisture data. J. Geophys. Res. Atmos. 2014, 119, 5128-5141. 2. Hossain, F.; Anagnostou, E. N. A two-dimensional satellite rainfall error model. IEEE Trans. Geosci. Remote Sens. 2006, 44, 1511-1522.

A nanoporous alumina microelectrode array for functional cell-chip coupling.

PubMed

Wesche, Manuel; Hüske, Martin; Yakushenko, Alexey; Brüggemann, Dorothea; Mayer, Dirk; Offenhäusser, Andreas; Wolfrum, Bernhard

2012-12-14

The design of electrode interfaces has a strong impact on cell-based bioelectronic applications. We present a new type of microelectrode array chip featuring a nanoporous alumina interface. The chip is fabricated in a combination of top-down and bottom-up processes using state-of-the-art clean room technology and self-assembled generation of nanopores by aluminum anodization. The electrode characteristics are investigated in phosphate buffered saline as well as under cell culture conditions. We show that the modified microelectrodes exhibit decreased impedance compared to planar microelectrodes, which is caused by a nanostructuring effect of the underlying gold during anodization. The stability and biocompatibility of the device are demonstrated by measuring action potentials from cardiomyocyte-like cells growing on top of the chip. Cross sections of the cell-surface interface reveal that the cell membrane seals the nanoporous alumina layer without bending into the sub-50 nm apertures. The nanoporous microelectrode array device may be used as a platform for combining extracellular recording of cell activity with stimulating topographical cues.

Integrated circuits based on conjugated polymer monolayer

DOE PAGES

Li, Mengmeng; Mangalore, Deepthi Kamath; Zhao, Jingbo; ...

2018-01-31

It is still a great challenge to fabricate conjugated polymer monolayer field-effect transistors (PoM-FETs) due to intricate crystallization and film formation of conjugated polymers. Here we demonstrate PoM-FETs based on a single monolayer of a conjugated polymer. The resulting PoM-FETs are highly reproducible and exhibit charge carrier mobilities reaching 3 cm 2 V -1 s -1. The high performance is attributed to the strong interactions of the polymer chains present already in solution leading to pronounced edge-on packing and well-defined microstructure in the monolayer. The high reproducibility enables the integration of discrete unipolar PoM-FETs into inverters and ring oscillators. Realmore » logic functionality has been demonstrated by constructing a 15-bit code generator in which hundreds of self-assembled PoM-FETs are addressed simultaneously. Lastly, our results provide the state-of-the-art example of integrated circuits based on a conjugated polymer monolayer, opening prospective pathways for bottom-up organic electronics.« less

A multi-protease, multi-dissociation, bottom-up-to-top-down proteomic view of the Loxosceles intermedia venom

PubMed Central

Trevisan-Silva, Dilza; Bednaski, Aline V.; Fischer, Juliana S.G.; Veiga, Silvio S.; Bandeira, Nuno; Guthals, Adrian; Marchini, Fabricio K.; Leprevost, Felipe V.; Barbosa, Valmir C.; Senff-Ribeiro, Andrea; Carvalho, Paulo C.

2017-01-01

Venoms are a rich source for the discovery of molecules with biotechnological applications, but their analysis is challenging even for state-of-the-art proteomics. Here we report on a large-scale proteomic assessment of the venom of Loxosceles intermedia, the so-called brown spider. Venom was extracted from 200 spiders and fractioned into two aliquots relative to a 10 kDa cutoff mass. Each of these was further fractioned and digested with trypsin (4 h), trypsin (18 h), pepsin (18 h), and chymotrypsin (18 h), then analyzed by MudPIT on an LTQ-Orbitrap XL ETD mass spectrometer fragmenting precursors by CID, HCD, and ETD. Aliquots of undigested samples were also analyzed. Our experimental design allowed us to apply spectral networks, thus enabling us to obtain meta-contig assemblies, and consequently de novo sequencing of practically complete proteins, culminating in a deep proteome assessment of the venom. Data are available via ProteomeXchange, with identifier PXD005523. PMID:28696408

Perceptual approaches to finding features in data

NASA Astrophysics Data System (ADS)

Rogowitz, Bernice E.

2013-03-01

Electronic imaging applications hinge on the ability to discover features in data. For example, doctors examine diagnostic images for tumors, broken bones and changes in metabolic activity. Financial analysts explore visualizations of market data to find correlations, outliers and interaction effects. Seismologists look for signatures in geological data to tell them where to drill or where an earthquake may begin. These data are very diverse, including images, numbers, graphs, 3-D graphics, and text, and are growing exponentially, largely through the rise in automatic data collection technologies such as sensors and digital imaging. This paper explores important trends in the art and science of finding features in data, such as the tension between bottom-up and top-down processing, the semantics of features, and the integration of human- and algorithm-based approaches. This story is told from the perspective of the IS and T/SPIE Conference on Human Vision and Electronic Imaging (HVEI), which has fostered research at the intersection between human perception and the evolution of new technologies.

Integrated circuits based on conjugated polymer monolayer

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

Li, Mengmeng; Mangalore, Deepthi Kamath; Zhao, Jingbo

It is still a great challenge to fabricate conjugated polymer monolayer field-effect transistors (PoM-FETs) due to intricate crystallization and film formation of conjugated polymers. Here we demonstrate PoM-FETs based on a single monolayer of a conjugated polymer. The resulting PoM-FETs are highly reproducible and exhibit charge carrier mobilities reaching 3 cm 2 V -1 s -1. The high performance is attributed to the strong interactions of the polymer chains present already in solution leading to pronounced edge-on packing and well-defined microstructure in the monolayer. The high reproducibility enables the integration of discrete unipolar PoM-FETs into inverters and ring oscillators. Realmore » logic functionality has been demonstrated by constructing a 15-bit code generator in which hundreds of self-assembled PoM-FETs are addressed simultaneously. Lastly, our results provide the state-of-the-art example of integrated circuits based on a conjugated polymer monolayer, opening prospective pathways for bottom-up organic electronics.« less

DeepFix: A Fully Convolutional Neural Network for Predicting Human Eye Fixations.

PubMed

Kruthiventi, Srinivas S S; Ayush, Kumar; Babu, R Venkatesh

2017-09-01

Understanding and predicting the human visual attention mechanism is an active area of research in the fields of neuroscience and computer vision. In this paper, we propose DeepFix, a fully convolutional neural network, which models the bottom-up mechanism of visual attention via saliency prediction. Unlike classical works, which characterize the saliency map using various hand-crafted features, our model automatically learns features in a hierarchical fashion and predicts the saliency map in an end-to-end manner. DeepFix is designed to capture semantics at multiple scales while taking global context into account, by using network layers with very large receptive fields. Generally, fully convolutional nets are spatially invariant-this prevents them from modeling location-dependent patterns (e.g., centre-bias). Our network handles this by incorporating a novel location-biased convolutional layer. We evaluate our model on multiple challenging saliency data sets and show that it achieves the state-of-the-art results.

Integrated circuits based on conjugated polymer monolayer.

PubMed

Li, Mengmeng; Mangalore, Deepthi Kamath; Zhao, Jingbo; Carpenter, Joshua H; Yan, Hongping; Ade, Harald; Yan, He; Müllen, Klaus; Blom, Paul W M; Pisula, Wojciech; de Leeuw, Dago M; Asadi, Kamal

2018-01-31

It is still a great challenge to fabricate conjugated polymer monolayer field-effect transistors (PoM-FETs) due to intricate crystallization and film formation of conjugated polymers. Here we demonstrate PoM-FETs based on a single monolayer of a conjugated polymer. The resulting PoM-FETs are highly reproducible and exhibit charge carrier mobilities reaching 3 cm 2  V -1  s -1 . The high performance is attributed to the strong interactions of the polymer chains present already in solution leading to pronounced edge-on packing and well-defined microstructure in the monolayer. The high reproducibility enables the integration of discrete unipolar PoM-FETs into inverters and ring oscillators. Real logic functionality has been demonstrated by constructing a 15-bit code generator in which hundreds of self-assembled PoM-FETs are addressed simultaneously. Our results provide the state-of-the-art example of integrated circuits based on a conjugated polymer monolayer, opening prospective pathways for bottom-up organic electronics.

How to fold a spin chain: Integrable boundaries of the Heisenberg XXX and Inozemtsev hyperbolic models

NASA Astrophysics Data System (ADS)

De La Rosa Gomez, Alejandro; MacKay, Niall; Regelskis, Vidas

2017-04-01

We present a general method of folding an integrable spin chain, defined on a line, to obtain an integrable open spin chain, defined on a half-line. We illustrate our method through two fundamental models with sl2 Lie algebra symmetry: the Heisenberg XXX and the Inozemtsev hyperbolic spin chains. We obtain new long-range boundary Hamiltonians and demonstrate that they exhibit Yangian symmetries, thus ensuring integrability of the models we obtain. The method presented provides a ;bottom-up; approach for constructing integrable boundaries and can be applied to any spin chain model.

Growth and Mortality Outcomes for Different Antiretroviral Therapy Initiation Criteria in Children aged 1–5 Years: A Causal Modelling Analysis

PubMed Central

Schomaker, Michael; Davies, Mary-Ann; Malateste, Karen; Renner, Lorna; Sawry, Shobna; N’Gbeche, Sylvie; Technau, Karl-Günter; Eboua, François; Tanser, Frank; Sygnaté-Sy, Haby; Phiri, Sam; Amorissani-Folquet, Madeleine; Cox, Vivian; Koueta, Fla; Chimbete, Cleophas; Lawson-Evi, Annette; Giddy, Janet; Amani-Bosse, Clarisse; Wood, Robin; Egger, Matthias; Leroy, Valeriane

2017-01-01

Background There is limited evidence regarding the optimal timing of initiating antiretroviral therapy (ART) in children. We conducted a causal modelling analysis in children aged 1–5 years from the International Epidemiologic Databases to Evaluate AIDS West/Southern-Africa collaboration to determine growth and mortality differences related to different CD4-based treatment initiation criteria, age groups and regions. Methods ART-naïve children of age 12–59 months at enrollment with at least one visit before ART initiation and one follow-up visit were included. We estimated 3-year growth and cumulative mortality from the start of follow-up for different CD4 criteria using g-computation. Results About one quarter of the 5826 included children was from West Africa (24.6%). The median (first; third quartile) CD4% at the first visit was 16% (11%;23%), the median weight-for-age z-scores and height-for-age z-scores were −1.5 (−2.7; −0.6) and −2.5 (−3.5; −1.5), respectively. Estimated cumulative mortality was higher overall, and growth was slower, when initiating ART at lower CD4 thresholds. After 3 years of follow-up, the estimated mortality difference between starting ART routinely irrespective of CD4 count and starting ART if either CD4 count<750 cells/mm3 or CD4%<25% was 0.2% (95%CI: −0.2%;0.3%), and the difference in the mean height-for-age z-scores of those who survived was −0.02 (95%CI: −0.04;0.01). Younger children aged 1–2 and children in West Africa had worse outcomes. Conclusions Our results demonstrate that earlier treatment initiation yields overall better growth and mortality outcomes, though we could not show any differences in outcomes between immediate ART and delaying until CD4 count/% falls below750/25%. PMID:26479876

Loss to follow-up trends in HIV-positive patients receiving antiretroviral treatment in Asia from 2003 to 2013

PubMed Central

De La Mata, Nicole L.; Ly, Penh Sun; Van Nguyen, Kinh; Merati, Tuti Parwati; Pham, Thuy Thanh; Lee, Man Po; Choi, Jun Yong; Ross, Jeremy; Law, Matthew G.; Ng, Oon Tek

2017-01-01

Introduction Over time there has been substantial improvement in antiretroviral treatment (ART) programmes, including expansion of services and increased patient engagement. We describe time trends in, and factors associated with, loss to follow-up (LTFU) in HIV-positive patients receiving ART in Asia. Methods Analysis included HIV-positive adults initiating ART in 2003-2013 at seven ART programmes in Asia. Patients LTFU had not attended the clinic for ≥180 days, had not died or transferred to another clinic. Patients were censored at recent clinic visit, follow-up to January 2014. We used cumulative incidence to compare LTFU and mortality between years of ART initiation. Factors associated with LTFU were evaluated using a competing risks regression model, adjusted for clinical site. Results A total of 8,305 patients were included. There were 743 patients LTFU and 352 deaths over 26,217 person-years (pys), a crude LTFU and mortality rate of 2.83 (2.64-3.05) per 100 pys and 1.34 (1.21-1.49) per 100 pys, respectively. At 24 months, the cumulative LTFU incidence increased from 4.3%(2.9-6.1%) in 2003-05 to 8.1%(7.1-9.2%) in 2006-09, then decreased to 6.7%(5.9-7.5%) in 2010-13. Concurrently, the cumulative mortality incidence decreased from 6.2%(4.5-8.2%) in 2003-05 to 3.3%(2.8-3.9%) in 2010-13. The risk of LTFU reduced in 2010-13 compared to 2006-09 (adjusted subhazard ratio=0.73, 0.69-0.99). Conclusions LTFU rates in HIV-positive patients receiving ART in our clinical sites have varied by the year of ART initiation, with rates declining in recent years while mortality rates have remained stable. Further increases in site-level resources are likely to contribute to additional reductions in LTFU for patients initiating in subsequent years. PMID:28129256

Multi-Country Analysis of Treatment Costs for HIV/AIDS (MATCH): Facility-Level ART Unit Cost Analysis in Ethiopia, Malawi, Rwanda, South Africa and Zambia

PubMed Central

Tagar, Elya; Sundaram, Maaya; Condliffe, Kate; Matatiyo, Blackson; Chimbwandira, Frank; Chilima, Ben; Mwanamanga, Robert; Moyo, Crispin; Chitah, Bona Mukosha; Nyemazi, Jean Pierre; Assefa, Yibeltal; Pillay, Yogan; Mayer, Sam; Shear, Lauren; Dain, Mary; Hurley, Raphael; Kumar, Ritu; McCarthy, Thomas; Batra, Parul; Gwinnell, Dan; Diamond, Samantha; Over, Mead

2014-01-01

Background Today's uncertain HIV funding landscape threatens to slow progress towards treatment goals. Understanding the costs of antiretroviral therapy (ART) will be essential for governments to make informed policy decisions about the pace of scale-up under the 2013 WHO HIV Treatment Guidelines, which increase the number of people eligible for treatment from 17.6 million to 28.6 million. The study presented here is one of the largest of its kind and the first to describe the facility-level cost of ART in a random sample of facilities in Ethiopia, Malawi, Rwanda, South Africa and Zambia. Methods & Findings In 2010–2011, comprehensive data on one year of facility-level ART costs and patient outcomes were collected from 161 facilities, selected using stratified random sampling. Overall, facility-level ART costs were significantly lower than expected in four of the five countries, with a simple average of $208 per patient-year (ppy) across Ethiopia, Malawi, Rwanda and Zambia. Costs were higher in South Africa, at $682 ppy. This included medications, laboratory services, direct and indirect personnel, patient support, equipment and administrative services. Facilities demonstrated the ability to retain patients alive and on treatment at these costs, although outcomes for established patients (2–8% annual loss to follow-up or death) were better than outcomes for new patients in their first year of ART (77–95% alive and on treatment). Conclusions This study illustrated that the facility-level costs of ART are lower than previously understood in these five countries. While limitations must be considered, and costs will vary across countries, this suggests that expanded treatment coverage may be affordable. Further research is needed to understand investment costs of treatment scale-up, non-facility costs and opportunities for more efficient resource allocation. PMID:25389777

Facile fabrication of uniaxial nanopatterns on shape memory polymer substrates using a complete bottom-up approach

NASA Astrophysics Data System (ADS)

Chen, Zhongbi; Krishnaswamy, Sridhar

2014-03-01

In earlier work, we have demonstrated an assisted self-assembly fabrication method for unidirectional submicron patterns using pre-programmed shape memory polymers (SMP) as the substrate in an organic/inorganic bilayer structure. In this paper, we propose a complete bottom-up method for fabrication of uniaxial wrinkles whose wavelength is below 300 nm. The method starts with using the aforementioned self-assembled bi-layer wrinkled surface as the template to make a replica of surface wrinkles on a PDMS layer which is spin-coated on a pre-programmed SMP substrate. When the shape recovery of the substrate is triggered by heating it to its transition temperature, the substrate has been programmed in such a way that it shrinks uniaxially to return to its permanent shape. Consequently, the wrinkle wavelength on PDMS reduces accordingly. A subsequent contact molding process is carried out on the PDMS layer spin-coated on another pre-programmed SMP substrate, but using the wrinkled PDMS surface obtained in the previous step as the master. By activating the shape recovery of the substrate, the wrinkle wavelength is further reduced a second time in a similar fashion. Our experiments showed that the starting wavelength of 640 nm decreased to 290 nm after two cycles of recursive molding. We discuss the advantages and limitations of our recursive molding approach compared to the prevalent top-down fabrication methods represented by lithography. The present study is expected to o er a simple and cost-e ective fabrication method of nano-scale uniaxial wrinkle patterns with the potential for large-scale mass-production.

Design of the Bottom-up Innovation project - a participatory, primary preventive, organizational level intervention on work-related stress and well-being for workers in Dutch vocational education

PubMed Central

2013-01-01

Background In the educational sector job demands have intensified, while job resources remained the same. A prolonged disbalance between demands and resources contributes to lowered vitality and heightened need for recovery, eventually resulting in burnout, sickness absence and retention problems. Until now stress management interventions in education focused mostly on strengthening the individual capacity to cope with stress, instead of altering the sources of stress at work at the organizational level. These interventions have been only partly effective in influencing burnout and well-being. Therefore, the “Bottom-up Innovation” project tests a two-phased participatory, primary preventive organizational level intervention (i.e. a participatory action approach) that targets and engages all workers in the primary process of schools. It is hypothesized that participating in the project results in increased occupational self-efficacy and organizational efficacy. The central research question: is an organization focused stress management intervention based on participatory action effective in reducing the need for recovery and enhancing vitality in school employees in comparison to business as usual? Methods/Design The study is designed as a controlled trial with mixed methods and three measurement moments: baseline (quantitative measures), six months and 18 months (quantitative and qualitative measures). At first follow-up short term effects of taking part in the needs assessment (phase 1) will be determined. At second follow-up the long term effects of taking part in the needs assessment will be determined as well as the effects of implemented tailored workplace solutions (phase 2). A process evaluation based on quantitative and qualitative data will shed light on whether, how and why the intervention (does not) work(s). Discussion “Bottom-up Innovation” is a combined effort of the educational sector, intervention providers and researchers. Results will provide insight into (1) the relation between participating in the intervention and occupational and organizational self-efficacy, (2) how an improved balance between job demands and job resources might affect need for recovery and vitality, in the short and long term, from an organizational perspective, and (3) success and fail factors for implementation of an organizational intervention. Trial registration number Netherlands Trial Register NTR3284 PMID:23947538

The Bottom-up Move within Vygotsky's Zone of Proximal Development: A Pedagogical Application for Teaching Agreement in Spanish as a Foreign Language

ERIC Educational Resources Information Center

Escandon, Arturo; Sanz, Montserrat

2011-01-01

This paper presents the findings of a longitudinal study in which two instructional methods to teach agreement features to first-year university students specializing in Spanish in Japan are compared. On the one hand, the control group was exposed to the traditional top-down teaching of agreement paradigms and were instructed to practice them…

Criteria for Comparing Domain Analysis Approaches Version 01.00.00

DTIC Science & Technology

1991-12-01

Down-Bottom-Up Domain Analysis Process (1990 Version) ..... 14 Figure 8. FODAs Domain Analysis Process ............................................ 16... FODA , which uses the Design Approach for Real-Time Systems (DARTS) design method (Gomaa 1984)? 1 1. hntmduction Domain analysis is still immature... Analysis Process 16 2. An Orvicw of Some Domain AnabAppro•d•a 2.4.3 ExAzs The FODA report illustrates the process by using the window management

Access to antiretroviral therapy in HIV-infected children aged 0–19 years in the International Epidemiology Databases to Evaluate AIDS (IeDEA) Global Cohort Consortium, 2004–2015: A prospective cohort study

PubMed Central

Desmonde, Sophie; Takassi, Elom; Edmonds, Andrew; Lumbiganon, Pagakrong; Pinto, Jorge; Malateste, Karen; McGowan, Catherine; Dicko, Fatoumata; Mubiana-Mbewe, Mwangelwa; Wools-Kaloustian, Kara; Davies, Mary-Ann

2018-01-01

Introduction Access to antiretroviral therapy (ART) is a global priority. However, the attrition across the continuum of care for HIV-infected children between their HIV diagnosis and ART initiation is not well known. We analyzed the time from enrollment into HIV care to ART initiation in HIV-infected children within the International Epidemiology Databases to Evaluate AIDS (IeDEA) Global Cohort Consortium. Methods and findings We included 135,479 HIV-1-infected children, aged 0–19 years and ART-naïve at enrollment, between 1 January 2004 and 31 December 2015, in IeDEA cohorts from Central Africa (3 countries; n = 4,948), East Africa (3 countries; n = 22,827), West Africa (7 countries; n = 7,372), Southern Africa (6 countries; n = 93,799), Asia-Pacific (6 countries; n = 4,045), and Latin America (7 countries; n = 2,488). Follow-up in these cohorts is typically every 3–6 months. We described time to ART initiation and missed opportunities (death or loss to follow-up [LTFU]: last clinical visit >6 months) since baseline (the date of HIV diagnosis or, if unavailable, date of enrollment). Cumulative incidence functions (CIFs) for and determinants of ART initiation were computed, with death and LTFU as competing risks. Among the 135,479 children included, 99,404 (73.4%) initiated ART, 1.9% died, 1.4% were transferred out, and 20.4% were lost to follow-up before ART initiation. The 24-month CIF for ART initiation was 68.2% (95% CI: 67.9%–68.4%); it was lower in sub-Saharan Africa—ranging from 49.8% (95% CI: 48.4%–51.2%) in Central Africa to 72.5% (95% CI: 71.5%–73.5%) in West Africa—compared to Latin America (71.0%, 95% CI: 69.1%–72.7%) and the Asia-Pacific (78.3%, 95% CI: 76.9%–79.6%). Adolescents aged 15–19 years and infants <1 year had the lowest cumulative incidence of ART initiation compared to other ages: 62.2% (95% CI: 61.6%–62.8%) and 66.4% (95% CI: 65.7%–67.0%), respectively. Overall, 49.1% were ART-eligible per local guidelines at baseline, of whom 80.6% initiated ART. The following children had lower cumulative incidence of ART initiation: female children (p < 0.01); those aged <1 year, 2–4 years, 5–9 years, and 15–19 years (versus those aged 10–14 years, p < 0.01); those who became eligible during follow-up (versus eligible at enrollment, p < 0.01); and those receiving care in low-income or lower-middle-income countries (p < 0.01). The main limitations of our study include left truncation and survivor bias, caused by deaths of children prior to enrollment, and use of enrollment date as a proxy for missing data on date of HIV diagnosis, which could have led to underestimation of the time between HIV diagnosis and ART initiation. Conclusions In this study, 68% of HIV-infected children initiated ART by 24 months. However, there was a substantial risk of LTFU before ART initiation, which may also represent undocumented mortality. In 2015, many obstacles to ART initiation remained, with substantial inequities. More effective and targeted interventions to improve access are needed to reach the target of treating 90% of HIV-infected children with ART. PMID:29727458

Search for Scalar Bottom Quark Pair Production with the ATLAS Detector in p p Collisions at s = 7 TeV

DOE PAGES

Aad, G.; Abbott, B.; Abdallah, J.; ...

2012-05-02

The results of a search for pair production of the scalar partners of bottom quarks in 2.05 fb -1 of p p collisions at √ s = 7 TeV using the ATLAS experiment are reported. Scalar bottom quarks are searched for in events with large missing transverse momentum and two jets in the final state, where both jets are identified as originating from a bottom quark. In an R -parity conserving minimal supersymmetric scenario, assuming that the scalar bottom quark decays exclusively into a bottom quark and a neutralino, 95% confidence-level upper limits are obtained in the ˜ b 1more » - ˜ χ 0 1 mass plane such that for neutralino masses below 60 GeV scalar bottom masses up to 390 GeV are excluded.« less

Search for scalar bottom quarks from gluino decays in collisions at.

PubMed

Abulencia, A; Acosta, D; Adelman, J; Affolder, T; Akimoto, T; Albrow, M G; Ambrose, D; Amerio, S; Amidei, D; Anastassov, A; Anikeev, K; Annovi, A; Antos, J; Aoki, M; Apollinari, G; Arguin, J-F; Arisawa, T; Artikov, A; Ashmanskas, W; Attal, A; Azfar, F; Azzi-Bacchetta, P; Azzurri, P; Bacchetta, N; Bachacou, H; Badgett, W; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Baroiant, S; Bartsch, V; Bauer, G; Bedeschi, F; Behari, S; Belforte, S; Bellettini, G; Bellinger, J; Belloni, A; Ben-Haim, E; Benjamin, D; Beretvas, A; Beringer, J; Berry, T; Bhatti, A; Binkley, M; Bisello, D; Bishai, M; Blair, R E; Blocker, C; Bloom, K; Blumenfeld, B; Bocci, A; Bodek, A; Boisvert, V; Bolla, G; Bolshov, A; Bortoletto, D; Boudreau, J; Bourov, S; Boveia, A; Brau, B; Bromberg, C; Brubaker, E; Budagov, J; Budd, H S; Budd, S; Burkett, K; Busetto, G; Bussey, P; Byrum, K L; Cabrera, S; Campanelli, M; Campbell, M; Canelli, F; Canepa, A; Carlsmith, D; Carosi, R; Carron, S; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavalli-Sforza, M; Cerri, A; Cerrito, L; Chang, S H; Chapman, J; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Chlebana, F; Cho, I; Cho, K; Chokheli, D; Chou, J P; Chu, P H; Chuang, S H; Chung, K; Chung, W H; Chung, Y S; Ciljak, M; Ciobanu, C I; Ciocci, M A; Clark, A; Clark, D; Coca, M; Connolly, A; Convery, M E; Conway, J; Cooper, B; Copic, K; Cordelli, M; Cortiana, G; Cruz, A; Cuevas, J; Culbertson, R; Cyr, D; DaRonco, S; D'Auria, S; D'onofrio, M; Dagenhart, D; de Barbaro, P; De Cecco, S; Deisher, A; De Lentdecker, G; Dell'Orso, M; Demers, S; Demortier, L; Deng, J; Deninno, M; De Pedis, D; Derwent, P F; Dionisi, C; Dittmann, J R; Dituro, P; Dörr, C; Dominguez, A; Donati, S; Donega, M; Dong, P; Donini, J; Dorigo, T; Dube, S; Ebina, K; Efron, J; Ehlers, J; Erbacher, R; Errede, D; Errede, S; Eusebi, R; Fang, H C; Farrington, S; Fedorko, I; Fedorko, W T; Feild, R G; Feindt, M; Fernandez, J P; Field, R; Flanagan, G; Flores-Castillo, L R; Foland, A; Forrester, S; Foster, G W; Franklin, M; Freeman, J C; Fujii, Y; Furic, I; Gajjar, A; Gallinaro, M; Galyardt, J; Garcia, J E; Garcia Sciverez, M; Garfinkel, A F; Gay, C; Gerberich, H; Gerchtein, E; Gerdes, D; Giagu, S; di Giovanni, G P; Giannetti, P; Gibson, A; Gibson, K; Ginsburg, C; Giokaris, N; Giolo, K; Giordani, M; Giunta, M; Giurgiu, G; Glagolev, V; Glenzinski, D; Gold, M; Goldschmidt, N; Goldstein, J; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González, O; Gorelov, I; Goshaw, A T; Gotra, Y; Goulianos, K; Gresele, A; Griffiths, M; Grinstein, S; Grosso-Pilcher, C; Grundler, U; Guimaraes da Costa, J; Haber, C; Hahn, S R; Hahn, K; Halkiadakis, E; Hamilton, A; Han, B-Y; Handler, R; Happacher, F; Hara, K; Hare, M; Harper, S; Harr, R F; Harris, R M; Hatakeyama, K; Hauser, J; Hays, C; Hayward, H; Heijboer, A; Heinemann, B; Heinrich, J; Hennecke, M; Herndon, M; Heuser, J; Hidas, D; Hill, C S; Hirschbuehl, D; Hocker, A; Holloway, A; Hou, S; Houlden, M; Hsu, S-C; Huffman, B T; Hughes, R E; Huston, J; Ikado, K; Incandela, J; Introzzi, G; Iori, M; Ishizawa, Y; Ivanov, A; Iyutin, B; James, E; Jang, D; Jayatilaka, B; Jeans, D; Jensen, H; Jeon, E J; Jones, M; Joo, K K; Jun, S Y; Junk, T R; Kamon, T; Kang, J; Karagoz-Unel, M; Karchin, P E; Kato, Y; Kemp, Y; Kephart, R; Kerzel, U; Khotilovich, V; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, M S; Kim, S B; Kim, S H; Kim, Y K; Kirby, M; Kirsch, L; Klimenko, S; Klute, M; Knuteson, B; Ko, B R; Kobayashi, H; Kondo, K; Kong, D J; Konigsberg, J; Kordas, K; Korytov, A; Kotwal, A V; Kovalev, A; Kraus, J; Kravchenko, I; Kreps, M; Kreymer, A; Kroll, J; Krumnack, N; Kruse, M; Krutelyov, V; Kuhlmann, S E; Kusakabe, Y; Kwang, S; Laasanen, A T; Lai, S; Lami, S; Lammel, S; Lancaster, M; Lander, R L; Lannon, K; Lath, A; Latino, G; Lazzizzera, I; Lecci, C; Lecompte, T; Lee, J; Lee, J; Lee, S W; Lefèvre, R; Leonardo, N; Leone, S; Levy, S; Lewis, J D; Li, K; Lin, C; Lin, C S; Lindgren, M; Lipeles, E; Liss, T M; Lister, A; Litvintsev, D O; Liu, T; Liu, Y; Lockyer, N S; Loginov, A; Loreti, M; Loverre, P; Lu, R-S; Lucchesi, D; Lujan, P; Lukens, P; Lungu, G; Lyons, L; Lys, J; Lysak, R; Lytken, E; Mack, P; MacQueen, D; Madrak, R; Maeshima, K; Maksimovic, P; Manca, G; Margaroli, F; Marginean, R; Marino, C; Martin, A; Martin, M; Martin, V; Martínez, M; Maruyama, T; Matsunaga, H; Mattson, M E; Mazini, R; Mazzanti, P; McFarland, K S; McGivern, D; McIntyre, P; McNamara, P; McNulty, R; Mehta, A; Menzemer, S; Menzione, A; Merkel, P; Mesropian, C; Messina, A; von der Mey, M; Miao, T; Miladinovic, N; Miles, J; Miller, R; Miller, J S; Mills, C; Milnik, M; Miquel, R; Miscetti, S; Mitselmakher, G; Miyamoto, A; Moggi, N; Mohr, B; Moore, R; Morello, M; Movilla Fernandez, P; Mülmenstädt, J; Mukherjee, A; Mulhearn, M; Muller, Th; Mumford, R; Munar, A; Murat, P; Nachtman, J; Nahn, S; Nakano, I; Napier, A; Naumov, D; Necula, V; Neu, C; Neubauer, M S; Nielsen, J; Nigmanov, T; Nodulman, L; Norniella, O; Ogawa, T; Oh, S H; Oh, Y D; Okusawa, T; Oldeman, R; Orava, R; Osterberg, K; Pagliarone, C; Palencia, E; Paoletti, R; Papadimitriou, V; Papikonomou, A; Paramonov, A A; Parks, B; Pashapour, S; Patrick, J; Pauletta, G; Paulini, M; Paus, C; Pellett, D E; Penzo, A; Phillips, T J; Piacentino, G; Piedra, J; Pitts, K; Plager, C; Pondrom, L; Pope, G; Portell, X; Poukhov, O; Pounder, N; Prakoshyn, F; Pronko, A; Proudfoot, J; Ptohos, F; Punzi, G; Pursley, J; Rademacker, J; Rahaman, A; Rakitin, A; Rappoccio, S; Ratnikov, F; Reisert, B; Rekovic, V; van Remortel, N; Renton, P; Rescigno, M; Richter, S; Rimondi, F; Rinnert, K; Ristori, L; Robertson, W J; Robson, A; Rodrigo, T; Rogers, E; Rolli, S; Roser, R; Rossi, M; Rossin, R; Rott, C; Ruiz, A; Russ, J; Rusu, V; Ryan, D; Saarikko, H; Sabik, S; Safonov, A; Sakumoto, W K; Salamanna, G; Salto, O; Saltzberg, D; Sanchez, C; Santi, L; Sarkar, S; Sato, K; Savard, P; Savoy-Navarro, A; Scheidle, T; Schlabach, P; Schmidt, E E; Schmidt, M P; Schmitt, M; Schwarz, T; Scodellaro, L; Scott, A L; Scribano, A; Scuri, F; Sedov, A; Seidel, S; Seiya, Y; Semenov, A; Semeria, F; Sexton-Kennedy, L; Sfiligoi, I; Shapiro, M D; Shears, T; Shepard, P F; Sherman, D; Shimojima, M; Shochet, M; Shon, Y; Shreyber, I; Sidoti, A; Siegrist, J L; Sill, A; Sinervo, P; Sisakyan, A; Sjolin, J; Skiba, A; Slaughter, A J; Sliwa, K; Smirnov, D; Smith, J R; Snider, F D; Snihur, R; Soderberg, M; Soha, A; Somalwar, S; Sorin, V; Spalding, J; Spinella, F; Squillacioti, P; Stanitzki, M; Staveris-Polykalas, A; St Dennis, R; Stelzer, B; Stelzer-Chilton, O; Stentz, D; Strologas, J; Stuart, D; Suh, J S; Sukhanov, A; Sumorok, K; Sun, H; Suzuki, T; Taffard, A; Tafirout, R; Takashima, R; Takeuchi, Y; Takikawa, K; Tanaka, M; Tanaka, R; Tecchio, M; Teng, P K; Terashi, K; Tether, S; Thom, J; Thompson, A S; Thomson, E; Tipton, P; Tiwari, V; Tkaczyk, S; Toback, D; Tokar, S; Tollefson, K; Tomura, T; Tonelli, D; Tönnesmann, M; Torre, S; Torretta, D; Tourneur, S; Trischuk, W; Tsuchiya, R; Tsuno, S; Turini, N; Ukegawa, F; Unverhau, T; Uozumi, S; Usynin, D; Vacavant, L; Vaiciulis, A; Vallecorsa, S; Varganov, A; Vataga, E; Velev, G; Veramendi, G; Veszpremi, V; Vickey, T; Vidal, R; Vila, I; Vilar, R; Vollrath, I; Volobouev, I; Würthwein, F; Wagner, P; Wagner, R G; Wagner, R L; Wagner, W; Wallny, R; Walter, T; Wan, Z; Wang, M J; Wang, S M; Warburton, A; Ward, B; Waschke, S; Waters, D; Watts, T; Weber, M; Wester, W C; Whitehouse, B; Whiteson, D; Wicklund, A B; Wicklund, E; Williams, H H; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, C; Worm, S; Wright, T; Wu, X; Wynne, S M; Yagil, A; Yamamoto, K; Yamaoka, J; Yamashita, Y; Yang, C; Yang, U K; Yao, W M; Yeh, G P; Yoh, J; Yorita, K; Yoshida, T; Yu, I; Yu, S S; Yun, J C; Zanello, L; Zanetti, A; Zaw, I; Zetti, F; Zhang, X; Zhou, J; Zucchelli, S

2006-05-05

We searched for scalar bottom quarks 156 pb(-1) of pp collisions at radicalS = 1.96 recorded by the Collider Detector at Fermilab II experiment at the Tevatron. Scalar bottom quarks can be produced from gluino decays in -parity conserving models of supersymmetry when the mass of the gluino exceeds that of the scalar bottom quark. Then, a scalar bottom quark can decay into a bottom quark and a neutralino. To search for this scenario, we investigated events with large missing transverse energy and at least three jets, two or more of which were identified as containing a secondary vertex from the hadronization of quarks. We found four candidate events, where 2.6 +/- 0.7 are expected from standard model processes, and placed 95% confidence level lower limits on gluino and scalar bottom quark masses of up to 280 and 240 GeV/c(2), respectively.

Determinants of Mortality and Loss to Follow-Up among Adults Enrolled in HIV Care Services in Rwanda

PubMed Central

Wang, Chunhui; Lahuerta, Maria; Nuwagaba-Biribonwoha, Harriet; Tayebwa, Edwin; Ingabire, Eugenie; Ingabire, Pacifique; Sahabo, Ruben; Twyman, Peter; Abrams, Elaine J.

2014-01-01

Background Antiretroviral therapy (ART) improves morbidity and mortality in patients with HIV, however high rates of loss to follow-up (LTF) and mortality have been documented in HIV care and treatment programs. Methods We analyzed routinely-collected data on HIV-infected patients ≥15 years enrolled at 41 healthcare facilities in Rwanda from 2005 to 2010. LTF was defined as not attending clinic in the last 12 months for pre-ART patients and 6 months for ART patients. For the pre-ART period, sub-distribution hazards models were constructed to estimate LTF and death to account for competing risks. Kaplan-Meier (KM) and Cox proportional hazards models were used for patients on ART. Results 31,033 ART-naïve adults were included, 64% were female and 75% were WHO stage I or II at enrollment. 17,569 (56%) patients initiated ART. Pre-ART competing risk estimates of LTF at 2 years was 11.2% (95%CI, 10.9–11.6%) and 2.9% for death (95%CI 2.7–3.1%). Among pre-ART patients, male gender was associated with higher LTF (adjusted sub-hazard ratio (aSHR) 1.3, 95%CI 1.1–1.5) and death (aSHR 1.7, 95%CI 1.4–2.1). Low CD4 count (CD4<100 vs. ≥350 aSHR 0.2, 95%CI 0.1–0.3) and higher WHO stage (WHO stage IV vs. stage I aSHR 0.4, 95%CI 0.2–0.6) were protective against pre-ART LTF. KM estimates for LTF and death in ART patients at 2 years were 4.4% (95%CI 4.4–4.5%) and 6.3% (95%CI 6.2–6.4%). In patients on ART, male gender was associated with LTF (adjusted hazard ratio (AHR) 1.4, 95%CI 1.2–1.7) and death (AHR1.3, 95%CI 1.2–1.5). Mortality was higher for ART patients ≥40 years and in those with lower CD4 count at ART initiation. Conclusions Low rates of LTF and death were founds among pre-ART and ART patients in Rwanda but greater efforts are needed to retain patients in care prior to ART initiation, particularly among those who are healthy at enrollment. PMID:24454931

Man induced change in community control in the north-western Black Sea: The top-down bottom-up balance.

PubMed

Bănaru, Daniela; Harmelin-Vivien, Mireille; Boudouresque, Charles F

2010-05-01

The present study shows how marine commercial fish food webs dramatically changed in the north-western Black Sea on both pelagic and benthic environments. Fisheries landings, diversity and equitability strongly decreased between 1965-1970 and 2001-2005. Fishes adapted their feeding behaviour to the increasingly low species diversity of the Black Sea communities. Their food web became poor and simplified following the loss of many top predator species and their trophic links. Linkage density, connectivity and Lyapunov stability proxy strongly decreased. The north-western Black Sea system switched from a complex top-down and bottom-up functioning pattern to a dominantly bottom-up functioning pattern. This study contributes to a better understanding of these transformations within the Danube-Black Sea system in the last decades. An attempt is made to relate these changes with river inputs, fisheries and coastal pollution. Copyright 2009 Elsevier Ltd. All rights reserved.

Disentangling the Importance of Psychological Predispositions and Social Constructions in the Organization of American Political Ideology.

PubMed

Verhulst, Brad; Hatemi, Peter K; Eaves, Lindon J

2012-06-01

Ideological preferences within the American electorate are contingent on both the environmental conditions that provide the content of the contemporary political debate and internal predispositions that motivate people to hold liberal or conservative policy preferences. In this article we apply Jost, Federico, and Napier's (2009) top-down/bottom-up theory of political attitude formation to a genetically informative population sample. In doing so, we further develop the theory by operationalizing the top-down pathway to be a function of the social environment and the bottom-up pathway as a latent set of genetic factors. By merging insights from psychology, behavioral genetics, and political science, we find strong support for the top-down/bottom-up framework that segregates the two independent pathways in the formation of political attitudes and identifies a different pattern of relationships between political attitudes at each level of analysis.

A comparison between molten carbonate fuel cells based hybrid systems using air and supercritical carbon dioxide Brayton cycles with state of the art technology

NASA Astrophysics Data System (ADS)

Sánchez, D.; Muñoz de Escalona, J. M.; Chacartegui, R.; Muñoz, A.; Sánchez, T.

A proposal for high efficiency hybrid systems based on molten carbonate fuel cells is presented in this paper. This proposal is based on adopting a closed cycle bottoming gas turbine using supercritical carbon dioxide as working fluid as opposed to open cycle hot air turbines typically used in this type of power generators. First, both bottoming cycles are compared for the same operating conditions, showing that their performances do not differ as much as initially expected, even if the initial objective of reducing compression work is accomplished satisfactorily. In view of these results, a profound review of research and industrial literature is carried out in order to determine realistic specifications for the principal components of the bottoming systems. From this analysis, it is concluded that an appropriate set of specifications must be developed for each bottoming cycle as the performances of compressor, turbine and recuperator differ significantly from one working fluid to another. Thus, when the operating conditions are updated, the performances of the resulting systems show a remarkable advantage of carbon dioxide based systems over conventional air units. Actually, the proposed hybrid system shows its capability to achieve 60% net efficiency, what represents a 10% increase with respect to the reference system.

Height-resolved large-sample INAA of a 1 m long, 13 cm diameter ditch-bottom sample

NASA Astrophysics Data System (ADS)

Blaauw, M.; Baas, H. W.; Donze, M.

2003-06-01

A facility for instrumental neutron activation analysis (INAA) of large samples (up to 1 m long and 15 cm diameter) has been built. Correction methods for the simultaneous occurrence of neutron self-shielding and gamma-ray self-attenuation effects have been implemented and tested with a variety of samples. Now, the method has been extended to allow for the interpretation of scanned, collimated measurements, where results are obtained for individual voxels. As a validation and demonstration, a ditch-bottom sample of the maximum size was taken in a frozen condition. It was cut in 2 cm slices, still frozen, and put together again with each slice in a 2 cm height Petri dish divided in three sections. This allowed for verification of the results by ordinary INAA. Possible explanations for the discrepancies we observed between ordinary and large-sample INAA in the region where the concentration gradients are the steepest are discussed.

Act local, think global: how the Malawi experience of scaling up antiretroviral treatment has informed global policy.

PubMed

Harries, Anthony D; Ford, Nathan; Jahn, Andreas; Schouten, Erik J; Libamba, Edwin; Chimbwandira, Frank; Maher, Dermot

2016-09-06

The scale-up of antiretroviral therapy (ART) in Malawi was based on a public health approach adapted to its resource-poor setting, with principles and practices borrowed from the successful tuberculosis control framework. From 2004 to 2015, the number of new patients started on ART increased from about 3000 to over 820,000. Despite being a small country, Malawi has made a significant contribution to the 15 million people globally on ART and has also contributed policy and service delivery innovations that have supported international guidelines and scale up in other countries. The first set of global guidelines for scaling up ART released by the World Health Organization (WHO) in 2002 focused on providing clinical guidance. In Malawi, the ART guidelines adopted from the outset a more operational and programmatic approach with recommendations on health systems and services that were needed to deliver HIV treatment to affected populations. Seven years after the start of national scale-up, Malawi launched a new strategy offering all HIV-infected pregnant women lifelong ART regardless of the CD4-cell count, named Option B+. This strategy was subsequently incorporated into a WHO programmatic guide in 2012 and WHO ART guidelines in 2013, and has since then been adopted by the majority of countries worldwide. In conclusion, the Malawi experience of ART scale-up has become a blueprint for a public health response to HIV and has informed international efforts to end the AIDS epidemic by 2030.

DAnTE: a statistical tool for quantitative analysis of –omics data

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

Polpitiya, Ashoka D.; Qian, Weijun; Jaitly, Navdeep

2008-05-03

DAnTE (Data Analysis Tool Extension) is a statistical tool designed to address challenges unique to quantitative bottom-up, shotgun proteomics data. This tool has also been demonstrated for microarray data and can easily be extended to other high-throughput data types. DAnTE features selected normalization methods, missing value imputation algorithms, peptide to protein rollup methods, an extensive array of plotting functions, and a comprehensive ANOVA scheme that can handle unbalanced data and random effects. The Graphical User Interface (GUI) is designed to be very intuitive and user friendly.

Pretreatment HIV-drug resistance in Mexico and its impact on the effectiveness of first-line antiretroviral therapy: a nationally representative 2015 WHO survey.

PubMed

Ávila-Ríos, Santiago; García-Morales, Claudia; Matías-Florentino, Margarita; Romero-Mora, Karla A; Tapia-Trejo, Daniela; Quiroz-Morales, Verónica S; Reyes-Gopar, Helena; Ji, Hezhao; Sandstrom, Paul; Casillas-Rodríguez, Jesús; Sierra-Madero, Juan; León-Juárez, Eddie A; Valenzuela-Lara, Marisol; Magis-Rodríguez, Carlos; Uribe-Zuñiga, Patricia; Reyes-Terán, Gustavo

2016-12-01

WHO has developed a global HIV-drug resistance surveillance strategy, including assessment of pretreatment HIV-drug resistance. We aimed to do a nationally representative survey of pretreatment HIV-drug resistance in Mexico using WHO-recommended methods. Among 161 Ministry of Health antiretroviral therapy (ART) clinics in Mexico, the largest, including 90% of ART initiators within the Ministry of Health (66 in total), were eligible for the survey. We used a probability-proportional-to-size design method to sample 25 clinics throughout the country. Consecutive ART-naive patients with HIV about to initiate treatment were invited to participate in the survey; individuals with previous exposure to ART were excluded. We assessed pretreatment HIV-drug resistance by Sanger sequencing and next-generation sequencing of viruses from plasma specimens from eligible participants with Stanford University HIV Drug Resistance Database methods. We obtained follow-up data for a median of 9·4 months (range 6-12) after enrolment. We investigated possible relations between demographic variables and pretreatment drug resistance with univariate and multivariate logistic regression. Between Feb 3 and July 30, 2015, we screened 288 patients in 25 clinics, from whom 264 provided successfully sequenced viruses with no evidence of current exposure to antiretroviral drugs. With the Sanger method, of these 264 participants, 41 (15·5%, 95% CI 11·4-20·5) had pretreatment resistance to any antiretroviral drug and 28 (10·6%, 7·2-15·0) had pretreatment resistance to non-nucleoside reverse transcriptase inhibitors (NNRTIs). At least low-level pretreatment resistance (Stanford penalty score ≥15) was noted in 13 (4 · 9%) of participants to efavirenz and in 23 (8·7%) to the combination tenofovir plus emtricitabine plus efavirenz. With next-generation sequencing, of 264 participants, 38 (14·4%, 95% CI 10·4-19·2) had pretreatment resistance to any antiretroviral drug and 26 (9·8%, 6·5-14·1) had pretreatment resistance to NNRTIs. After median follow-up of 8 months (IQR 6·5-9·4, range 5-11) after ART initiation, 97 (72%) of 135 NNRTI initiators achieved viral suppression (<50 copies per mL) compared with ten (40%) of 25 individuals who started with protease inhibitor-based regimens (p=0·0045). After multivariate regression considering pretreatment resistance and initial ART regimen as composite variables, people starting NNRTIs with pretreatment drug resistance achieved significantly lower viral suppression (odds ratio 0·24, 95% CI 0·07-0·74; p=0·014) than patients without NNRTI resistance. High levels of pretreatment drug resistance were noted in Mexico, and NNRTI pretreatment drug resistance significantly reduced the effectiveness of first-line ART regimens based on these drugs. Baseline HIV-drug resistance testing for initial ART follow-up and decision making should be considered. The Mexican Government and Consejo Nacional de Ciencia y Tecnología. Copyright © 2016 Elsevier Ltd. All rights reserved.

Gender Difference in 2-Year Mortality and Immunological Response to ART in an HIV-Infected Chinese Population, 2006–2008

PubMed Central

Dou, Zhihui; Xu, Jiahong; Jiao, Jin Hua; Ma, Ye; Durako, Stephen; Yu, Lan; Zhao, Yan; Zhang, Fujie

2011-01-01

Background Since it was initiated in 2002, the China Free Antiretroviral Treatment (ART) Program has been progressing from an emergency response to a standardized treatment and care system. As of December 31, 2009, a total of 81,880 patients in 31 provinces, autonomous regions, and special municipalities received free ART. Gender differences, however, in mortality and immunological response to ART in this cohort have never been described. Objective To understand whether women and men who enrolled in the China National Free ART Program responded equally well to the treatment. Methods A retrospective analysis of the national free ART databases from June 2006–December 2008 was performed. HIV-infected subjects who were 18 years or older, ART naïve at baseline, and on a 3TC regimen enrolled in the program from June 1 to December 31, 2006, were included in this study, then followed up to 2 years. Results Among 3457 enrolled subjects who met the inclusion criteria, 59.2% were male and 40.8% female. The majority of the subjects were 19–44 years old (77%) and married (72%). Over the full 24 months of follow-up, the mortality rate was 19.0% in males and 11.4% in females (p = 0.0014). Males on therapy for 3–24 months were more likely to die than females (HR = 1.46, 95% CI: 1.04–2.06, p = 0.0307) after adjusting for baseline characteristics. Compared to men, women had higher CD4+ counts over time after initiating ART (p<0.0001). Conclusions Our study showed that women had an overall lower mortality and higher CD4+ counts than men in response to ART treatment, which may be attributed to adherence, biological factors, social, cultural and economic reasons. Further study is needed to explore these factors that might contribute to the gender differences in mortality and immunological response to ART. PMID:21857947

Scale-up of national antiretroviral therapy programs: progress and challenges in the Asia Pacific region.

PubMed

Srikantiah, Padmini; Ghidinelli, Massimo; Bachani, Damodar; Chasombat, Sanchai; Daoni, Esorom; Mustikawati, Dyah E; Nhan, Do T; Pathak, Laxmi R; San, Khin O; Vun, Mean C; Zhang, Fujie; Lo, Ying-Ru; Narain, Jai P

2010-09-01

There has been tremendous scale-up of antiretroviral therapy (ART) services in the Asia Pacific region, which is home to an estimated 4.7 million persons living with HIV/AIDS. We examined treatment scale-up, ART program practices, and clinical outcome data in the nine low-and-middle-income countries that share over 95% of the HIV burden in the region. Standardized indicators for ART scale-up and treatment outcomes were examined for Cambodia, China, India, Indonesia, Myanmar, Nepal, Papua New Guinea, Thailand, and Vietnam using data submitted by each country to the WHO/The Joint United Nations Programme on HIV/AIDS (UNAIDS)/UNICEF joint framework tool for monitoring the health sector response to HIV/AIDS. Data on ART program practices were abstracted from National HIV Treatment Guidelines for each country. At the end of 2009, over 700,000 HIV-infected persons were receiving ART in the nine focus countries. Treatment coverage varies widely in the region, ranging from 16 to 93%. All nine countries employ a public health approach to ART services and provide a standardized first-line nonnucleoside reverse transcriptase inhibitor-based regimen. Among patients initiated on first-line ART in these countries, 65-88% remain alive and on treatment 12 months later. Over 50% of mortality occurs in the first 6 months of therapy, and losses to follow-up range from 8 to 16% at 2 years. Impressive ART scale-up efforts in the region have resulted in significant improvements in survival among persons receiving therapy. Continued funding support and political commitment will be essential for further expansion of public sector ART services to those in need. To improve treatment outcomes, national programs should focus on earlier identification of persons requiring ART, decentralization of ART services, and the development of stronger healthcare systems to support the provision of a continuum of HIV care.

"For a Lot of People, Radio Is a Lifeline"

ERIC Educational Resources Information Center

Stanistreet, Paul

2011-01-01

In this article, the author talks about Up for Arts, a Liverpool-based radio project aimed at promoting engagement in the arts. Up for Arts is a unique social action project which uses radio as a means of increasing public engagement in the voluntary arts and crafts. Its success has depended not only on the commitment of its partner organisations…

Tsunami Simulation Method Assimilating Ocean Bottom Pressure Data Near a Tsunami Source Region

NASA Astrophysics Data System (ADS)

Tanioka, Yuichiro

2018-02-01

A new method was developed to reproduce the tsunami height distribution in and around the source area, at a certain time, from a large number of ocean bottom pressure sensors, without information on an earthquake source. A dense cabled observation network called S-NET, which consists of 150 ocean bottom pressure sensors, was installed recently along a wide portion of the seafloor off Kanto, Tohoku, and Hokkaido in Japan. However, in the source area, the ocean bottom pressure sensors cannot observe directly an initial ocean surface displacement. Therefore, we developed the new method. The method was tested and functioned well for a synthetic tsunami from a simple rectangular fault with an ocean bottom pressure sensor network using 10 arc-min, or 20 km, intervals. For a test case that is more realistic, ocean bottom pressure sensors with 15 arc-min intervals along the north-south direction and sensors with 30 arc-min intervals along the east-west direction were used. In the test case, the method also functioned well enough to reproduce the tsunami height field in general. These results indicated that the method could be used for tsunami early warning by estimating the tsunami height field just after a great earthquake without the need for earthquake source information.

Theory-Driven Intervention for Changing Personality: Expectancy Value Theory, Behavioral Activation, and Conscientiousness

PubMed Central

Magidson, Jessica F.; Roberts, Brent; Collado-Rodriguez, Anahi; Lejuez, C.W.

2013-01-01

Considerable evidence suggests that personality traits may be changeable, raising the possibility that personality traits most linked to health problems can be modified with intervention. A growing body of research suggests that problematic personality traits may be altered with behavioral intervention using a bottom-approach. That is, by targeting core behaviors that underlie personality traits with the goal of engendering new, healthier patterns of behavior that over time become automatized and manifest in changes in personality traits. Nevertheless, a bottom-up model for changing personality traits is somewhat diffuse and requires clearer integration of theory and relevant interventions to enable real clinical application. As such, this manuscript proposes a set of guiding principles for theory-driven modification of targeted personality traits using a bottom-up approach, focusing specifically on targeting the trait of conscientiousness using a relevant behavioral intervention, Behavioral Activation (BA), considered within the motivational framework of Expectancy Value Theory (EVT). We conclude with a real case example of the application of BA to alter behaviors counter to conscientiousness in a substance dependent patient, highlighting the EVT principles most relevant to the approach and the importance and viability of a theoretically-driven, bottom-up approach to changing personality traits. PMID:23106844

Assessing Top-Down and Bottom-Up Contributions to Auditory Stream Segregation and Integration With Polyphonic Music

PubMed Central

Disbergen, Niels R.; Valente, Giancarlo; Formisano, Elia; Zatorre, Robert J.

2018-01-01

Polyphonic music listening well exemplifies processes typically involved in daily auditory scene analysis situations, relying on an interactive interplay between bottom-up and top-down processes. Most studies investigating scene analysis have used elementary auditory scenes, however real-world scene analysis is far more complex. In particular, music, contrary to most other natural auditory scenes, can be perceived by either integrating or, under attentive control, segregating sound streams, often carried by different instruments. One of the prominent bottom-up cues contributing to multi-instrument music perception is their timbre difference. In this work, we introduce and validate a novel paradigm designed to investigate, within naturalistic musical auditory scenes, attentive modulation as well as its interaction with bottom-up processes. Two psychophysical experiments are described, employing custom-composed two-voice polyphonic music pieces within a framework implementing a behavioral performance metric to validate listener instructions requiring either integration or segregation of scene elements. In Experiment 1, the listeners' locus of attention was switched between individual instruments or the aggregate (i.e., both instruments together), via a task requiring the detection of temporal modulations (i.e., triplets) incorporated within or across instruments. Subjects responded post-stimulus whether triplets were present in the to-be-attended instrument(s). Experiment 2 introduced the bottom-up manipulation by adding a three-level morphing of instrument timbre distance to the attentional framework. The task was designed to be used within neuroimaging paradigms; Experiment 2 was additionally validated behaviorally in the functional Magnetic Resonance Imaging (fMRI) environment. Experiment 1 subjects (N = 29, non-musicians) completed the task at high levels of accuracy, showing no group differences between any experimental conditions. Nineteen listeners also participated in Experiment 2, showing a main effect of instrument timbre distance, even though within attention-condition timbre-distance contrasts did not demonstrate any timbre effect. Correlation of overall scores with morph-distance effects, computed by subtracting the largest from the smallest timbre distance scores, showed an influence of general task difficulty on the timbre distance effect. Comparison of laboratory and fMRI data showed scanner noise had no adverse effect on task performance. These Experimental paradigms enable to study both bottom-up and top-down contributions to auditory stream segregation and integration within psychophysical and neuroimaging experiments. PMID:29563861

Outcome assessment of decentralization of antiretroviral therapy provision in a rural district of Malawi using an integrated primary care model.

PubMed

Chan, Adrienne K; Mateyu, Gabriel; Jahn, Andreas; Schouten, Erik; Arora, Paul; Mlotha, William; Kambanji, Marion; van Lettow, Monique

2010-06-01

To assess the effect of decentralization (DC) of antiretroviral therapy (ART) provision in a rural district of Malawi using an integrated primary care model. Between October 2004 and December 2008, 8093 patients (63% women) were registered for ART. Of these, 3440 (43%) were decentralized to health centres for follow-up ART care. We applied multivariate regression analysis that adjusted for sex, age, clinical stage at initiation, type of regimen, presence of side effects because of ART, and duration of treatment and follow-up at site of analysis. Patients managed at health centres had lower mortality [adjusted OR 0.19 (95% C.I. 0.15-0.25)] and lower loss to follow-up (defaulted from treatment) [adjusted OR 0.48 (95% C.I. 0.40-0.58)]. During the first 10 months of follow-up, those decentralized to health centres were approximately 60% less likely to default than those not decentralized; and after 10 months of follow-up, 40% less likely to default. DC was significantly associated with a reduced risk of death from 0 to 25 months of follow-up. The lower mortality may be explained by the selection of stable patients for DC, and the mentorship and supportive supervision of lower cadre health workers to identify and refer complicated cases. Decentralization of follow-up ART care to rural health facilities, using an integrated primary care model, appears a safe and effective way to rapidly scale-up ART and improves both geographical equity in access to HIV-related services and adherence to ART.

Vertical Cable Seismic Survey for SMS exploration

NASA Astrophysics Data System (ADS)

Asakawa, Eiichi; Murakami, Fumitoshi; Tsukahara, Hotoshi; Mizohata, Shigeharu

2014-05-01

The Vertical Cable Seismic (VCS) survey is one of the reflection seismic methods. It uses hydrophone arrays vertically moored from the seafloor to record acoustic waves generated by sea-surface, deep-towed or ocean bottom sources. Analyzing the reflections from the sub-seabed, we could look into the subsurface structure. Because the VCS is an efficient high-resolution 3D seismic survey method for a spatially-bounded area, we proposed it for the SMS survey tool development program that the Ministry of Education, Culture, Sports, Science and Technology (MEXT) started in 2009. We have been developing the VCS survey system, including not only data acquisition hardware but data processing and analysis technique. We carried out several VCS surveys combining with surface towed source, deep towed source and ocean bottom source. The water depths of these surveys are from 100m up to 2100 m. Through these experiments, our VCS data acquisition system has been also completed. But the data processing techniques are still on the way. One of the most critical issues is the positioning in the water. The uncertainty in the positions of the source and of the hydrophones in water degraded the quality of subsurface image. GPS navigation system is available on sea surface, but in case of deep-towed source or ocean bottom source, the accuracy of shot position with SSBL/USBL is not sufficient for the very high-resolution imaging. We have developed a new approach to determine the positions in water using the travel time data from the source to VCS hydrophones. In 2013, we have carried out the second VCS survey using the surface-towed high-voltage sparker and ocean bottom source in the Izena Cauldron, which is one of the most promising SMS areas around Japan. The positions of ocean bottom source estimated by this method are consistent with the VCS field records. The VCS data with the sparker have been processed with 3D PSTM. It gives the very high resolution 3D volume deeper than two hundred meters. Our VCS system has been demonstrated as a promising survey tool for the SMS exploration.

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

Ge, Zhen-Hua; Wei, Kaya; Lewis, Hutton

A hydrothermal approach was employed to efficiently synthesize SnSe nanorods. The nanorods were consolidated into polycrystalline SnSe by spark plasma sintering for low temperature electrical and thermal properties characterization. The low temperature transport properties indicate semiconducting behavior with a typical dielectric temperature dependence of the thermal conductivity. The transport properties are discussed in light of the recent interest in this material for thermoelectric applications. The nanorod growth mechanism is also discussed in detail. - Graphical abstract: SnSe nanorods were synthesized by a simple hydrothermal method through a bottom-up approach. Micron sized flower-like crystals changed to nanorods with increasing hydrothermal temperature.more » Low temperature transport properties of polycrystalline SnSe, after SPS densification, were reported for the first time. This bottom-up synthetic approach can be used to produce phase-pure dense polycrystalline materials for thermoelectrics applications. - Highlights: • SnSe nanorods were synthesized by a simple and efficient hydrothermal approach. • The role of temperature, time and NaOH content was investigated. • SPS densification allowed for low temperature transport properties measurements. • Transport measurements indicate semiconducting behavior.« less

Macro Scale Independently Homogenized Subcells for Modeling Braided Composites

NASA Technical Reports Server (NTRS)

Blinzler, Brina J.; Goldberg, Robert K.; Binienda, Wieslaw K.

2012-01-01

An analytical method has been developed to analyze the impact response of triaxially braided carbon fiber composites, including the penetration velocity and impact damage patterns. In the analytical model, the triaxial braid architecture is simulated by using four parallel shell elements, each of which is modeled as a laminated composite. Currently, each shell element is considered to be a smeared homogeneous material. The commercial transient dynamic finite element code LS-DYNA is used to conduct the simulations, and a continuum damage mechanics model internal to LS-DYNA is used as the material constitutive model. To determine the stiffness and strength properties required for the constitutive model, a top-down approach for determining the strength properties is merged with a bottom-up approach for determining the stiffness properties. The top-down portion uses global strengths obtained from macro-scale coupon level testing to characterize the material strengths for each subcell. The bottom-up portion uses micro-scale fiber and matrix stiffness properties to characterize the material stiffness for each subcell. Simulations of quasi-static coupon level tests for several representative composites are conducted along with impact simulations.

Relative Importance of Biotic and Abiotic Forces on the Composition and Dynamics of a Soft-Sediment Intertidal Community

PubMed Central

Barbeau, Myriam A.

2016-01-01

Top-down, bottom-up, middle-out and abiotic factors are usually viewed as main forces structuring biological communities, although assessment of their relative importance, in a single study, is rarely done. We quantified, using multivariate methods, associations between abiotic and biotic (top-down, bottom-up and middle-out) variables and infaunal population/community variation on intertidal mudflats in the Bay of Fundy, Canada, over two years. Our analysis indicated that spatial structural factors like site and plot accounted for most of the community and population variation. Although we observed a significant relationship between the community/populations and the biotic and abiotic variables, most were of minor importance relative to the structural factors. We suggest that community and population structure were relatively uncoupled from the structuring influences of biotic and abiotic factors in this system because of high concentrations of resources that sustain high densities of infauna and limit exploitative competition. Furthermore, we hypothesize that the infaunal community primarily reflects stochastic spatial events, namely a “first come, first served” process. PMID:26790098

Characteristics Air Flow in Room Chamber Test Refrigerator Household Energy Consumption with Inlet Flow Variation

NASA Astrophysics Data System (ADS)

Susanto, Edy; Idrus Alhamid, M.; Nasruddin; Budihardjo

2018-03-01

Room Chamber is the most important in making a good Testing Laboratory. In this study, the 2-D modeling conducted to assess the effect placed the inlet on designing a test chamber room energy consumption of household refrigerators. Where the geometry room chamber is rectangular and approaching the enclosure conditions. Inlet varied over the side parallel to the outlet and compared to the inlet where the bottom is made. The purpose of this study was to determine and define the characteristics of the airflow in the room chamber using CFD simulation. CFD method is used to obtain flow characteristics in detail, in the form of vector flow velocity and temperature distribution inside the chamber room. The result found that the position of the inlet parallel to the outlet causes air flow cannot move freely to the side of the floor, even flow of air moves up toward the outlet. While by making the inlet is below, the air can move freely from the bottom up to the side of the chamber room wall as well as to help uniform flow.

Programmable DNA tile self-assembly using a hierarchical sub-tile strategy.

PubMed

Shi, Xiaolong; Lu, Wei; Wang, Zhiyu; Pan, Linqiang; Cui, Guangzhao; Xu, Jin; LaBean, Thomas H

2014-02-21

DNA tile based self-assembly provides a bottom-up approach to construct desired nanostructures. DNA tiles have been directly constructed from ssDNA and readily self-assembled into 2D lattices and 3D superstructures. However, for more complex lattice designs including algorithmic assemblies requiring larger tile sets, a more modular approach could prove useful. This paper reports a new DNA 'sub-tile' strategy to easily create whole families of programmable tiles. Here, we demonstrate the stability and flexibility of our sub-tile structures by constructing 3-, 4- and 6-arm DNA tiles that are subsequently assembled into 2D lattices and 3D nanotubes according to a hierarchical design. Assembly of sub-tiles, tiles, and superstructures was analyzed using polyacrylamide gel electrophoresis and atomic force microscopy. DNA tile self-assembly methods provide a bottom-up approach to create desired nanostructures; the sub-tile strategy adds a useful new layer to this technique. Complex units can be made from simple parts. The sub-tile approach enables the rapid redesign and prototyping of complex DNA tile sets and tiles with asymmetric designs.

Outcomes of antiretroviral treatment programmes in rural Lesotho: health centres and hospitals compared.

PubMed

Labhardt, Niklaus Daniel; Keiser, Olivia; Sello, Motlalepula; Lejone, Thabo Ishmael; Pfeiffer, Karolin; Davies, Mary-Ann; Egger, Matthias; Ehmer, Jochen; Wandeler, Gilles

2013-11-21

Lesotho was among the first countries to adopt decentralization of care from hospitals to nurse-led health centres (HCs) to scale up the provision of antiretroviral therapy (ART). We compared outcomes between patients who started ART at HCs and hospitals in two rural catchment areas in Lesotho. The two catchment areas comprise two hospitals and 12 HCs. Patients ≥16 years starting ART at a hospital or HC between 2008 and 2011 were included. Loss to follow-up (LTFU) was defined as not returning to the facility for ≥180 days after the last visit, no follow-up (no FUP) as not returning after starting ART, and retention in care as alive and on ART at the facility. The data were analysed using logistic regression, competing risk regression and Kaplan-Meier methods. Multivariable analyses were adjusted for sex, age, CD4 cell count, World Health Organization stage, catchment area and type of ART. All analyses were stratified by gender. Of 3747 patients, 2042 (54.5%) started ART at HCs. Both women and men at hospitals had more advanced clinical and immunological stages of disease than those at HCs. Over 5445 patient-years, 420 died and 475 were LTFU. Kaplan-Meier estimates for three-year retention were 68.7 and 69.7% at HCs and hospitals, respectively, among women (p=0.81) and 68.8% at HCs versus 54.7% at hospitals among men (p<0.001). These findings persisted in adjusted analyses, with similar retention at HCs and hospitals among women (odds ratio (OR): 0.89, 95% confidence interval (CI): 0.73-1.09) and higher retention at HCs among men (OR: 1.53, 95% CI: 1.20-1.96). The latter result was mainly driven by a lower proportion of patients LTFU at HCs (OR: 0.68, 95% CI: 0.51-0.93). In rural Lesotho, overall retention in care did not differ significantly between nurse-led HCs and hospitals. However, men seemed to benefit most from starting ART at HCs, as they were more likely to remain in care in these facilities compared to hospitals.

[The evolution of vacuum extraction in obstetrics].

PubMed

Nikolov, A

2010-01-01

Vacuum extraction is one of the methods for assisted vaginal delivery. In this article the evolution of vacuum extraction in obstetrics is been discussed. Historical facts and data from the invention up to state-of-the-art vacuum systems in modern obstetrics are presented.

Acceptability of obtaining hair samples for assessing antiretroviral therapy (ART) exposure amongst alcohol drinking ART recipients in Tshwane, South Africa.

PubMed

Kekwaletswe, C T; Nkosi, S; Kitleli, N B; Myers, B; Shuper, P; Parry, C D H; Morojele, N K

2018-05-20

To achieve the maximal therapeutic benefits of antiretroviral therapy (ART), high adherence is required. In South Africa, ART recipients are usually counselled by their health care providers to stop drinking alcohol, as heavy alcohol use compromises ART adherence. Patients who continue drinking alcohol tend to hide their alcohol-related adherence challenges from their health care providers. Objective measures of ART adherence/exposure may help to better identify drinkers who could benefit from ART adherence enhancement interventions. To evaluate the acceptability of collecting hair samples to objectively assess ART exposure among alcohol drinkers, we conducted four mixed-gender focus group discussions (FGDs) with alcohol drinking ART recipients at two ART sites in Tshwane, South Africa. Data were analysed using content analysis. ART recipients found hair sample testing for ART exposure to be novel and therefore expected that some ART recipients would initially be hesitant to provide a sample. Participants thought that the acceptability of hair sample collection could be enhanced by providing a full explanation of how the hair sample would be obtained and what the testing would entail. Participants also viewed hair sample testing as a viable and desirable alternative to blood sample testing for ART exposure. Some worries about the possible use of hair samples for witchcraft and the symbolic nature of hair were brought up, but these were not seen as insurmountable concerns. In conclusion, hair sample testing is a potentially acceptable method of assessing ART exposure amongst ART recipients who drink alcohol.

Examining the Effects of Art Therapy on Reoccurring Tobacco Use in a Taiwanese Youth Population: A Mixed-Method Study.

PubMed

Hong, Rei-Mei; Guo, Su-Er; Huang, Chun-Sheng; Yin, Cheng

2018-03-21

Cigarette smoking is a primary risk factor affecting mental and physical health worldwide. Many chronic diseases are closely related to smoking. Adolescents in Taiwan are increasingly using tobacco, especially in rural areas. This research project used a mixed-method study to examine the effects of art therapy on smoking cessation in rural Taiwanese youth smokers. Participants from years 10-11, were drawn from three senior high schools in Taiwan. The experimental group participated in a six-week smoking cessation intervention using art therapy. The comparison group participated in typical courses on smoking cessation. Quantitative measures included need for smoking, nicotine dependence, self-esteem, self-efficacy, and smoking cessation status. Qualitative analysis was based on phenomenology. A total of 66 students (n = 40 experimental group; n = 26 comparison group) were the subjects of quantitative analysis. No differences were noted in baseline characteristics of groups. Generalized estimating equation analyses suggested significant between-group differences in change from pre- to follow-up test scores in the "social domain" (B = -5.12, p < 0.05). Qualitative data (n = 17 experimental group; n = 10 control group) suggested three domains: effects of art therapy on smoking prevention, benefits of art therapy on other outcome measures, and comparison between art therapy and traditional smoking cessation programs. Conclusions/importance: The findings of this study can potentially contribute significantly to existing knowledge regarding the perceptions of art therapy on reoccurring tobacco use in Taiwanese youth.

A new optimization method using a compressed sensing inspired solver for real-time LDR-brachytherapy treatment planning

NASA Astrophysics Data System (ADS)

Guthier, C.; Aschenbrenner, K. P.; Buergy, D.; Ehmann, M.; Wenz, F.; Hesser, J. W.

2015-03-01

This work discusses a novel strategy for inverse planning in low dose rate brachytherapy. It applies the idea of compressed sensing to the problem of inverse treatment planning and a new solver for this formulation is developed. An inverse planning algorithm was developed incorporating brachytherapy dose calculation methods as recommended by AAPM TG-43. For optimization of the functional a new variant of a matching pursuit type solver is presented. The results are compared with current state-of-the-art inverse treatment planning algorithms by means of real prostate cancer patient data. The novel strategy outperforms the best state-of-the-art methods in speed, while achieving comparable quality. It is able to find solutions with comparable values for the objective function and it achieves these results within a few microseconds, being up to 542 times faster than competing state-of-the-art strategies, allowing real-time treatment planning. The sparse solution of inverse brachytherapy planning achieved with methods from compressed sensing is a new paradigm for optimization in medical physics. Through the sparsity of required needles and seeds identified by this method, the cost of intervention may be reduced.

A new optimization method using a compressed sensing inspired solver for real-time LDR-brachytherapy treatment planning.

PubMed

Guthier, C; Aschenbrenner, K P; Buergy, D; Ehmann, M; Wenz, F; Hesser, J W

2015-03-21

This work discusses a novel strategy for inverse planning in low dose rate brachytherapy. It applies the idea of compressed sensing to the problem of inverse treatment planning and a new solver for this formulation is developed. An inverse planning algorithm was developed incorporating brachytherapy dose calculation methods as recommended by AAPM TG-43. For optimization of the functional a new variant of a matching pursuit type solver is presented. The results are compared with current state-of-the-art inverse treatment planning algorithms by means of real prostate cancer patient data. The novel strategy outperforms the best state-of-the-art methods in speed, while achieving comparable quality. It is able to find solutions with comparable values for the objective function and it achieves these results within a few microseconds, being up to 542 times faster than competing state-of-the-art strategies, allowing real-time treatment planning. The sparse solution of inverse brachytherapy planning achieved with methods from compressed sensing is a new paradigm for optimization in medical physics. Through the sparsity of required needles and seeds identified by this method, the cost of intervention may be reduced.

Impact of Socioeconomic Inequality on Access, Adherence, and Outcomes of Antiretroviral Treatment Services for People Living with HIV/AIDS in Vietnam

PubMed Central

Nguyen, Long Hoang; Nguyen, Anh Tuan; Latkin, Noah Reed Knowlton; Tran, Ngoc Kim; Minh Thuc, Vu Thi; Nguyen, Huong Lan Thi; Phan, Huong Thu Thi; Le, Huong Thi; Tran, Tho Dinh; Latkin, Carl A.

2016-01-01

Background Ensuring an equal benefit across different patient groups is necessary while scaling up free-of-charge antiretroviral treatment (ART) services. This study aimed to measure the disparity in access, adherence, and outcomes of ART in Vietnam and the effects of socioeconomic status (SES) characteristics on the levels of inequality. Methods A cross-sectional study was conducted in 1133 PLWH in Vietnam. ART access, adherence, and treatment outcomes were self-reported using a structured questionnaire. Wealth-related inequality was calculated using a concentration index, and a decomposition analysis was used to determine the contribution of each SES variable to inequality in access, adherence, and outcomes of ART. Results Based on SES, minor inequality was found in ART access and adherence while there was considerable inequality in ART outcomes. Poor people were more likely to start treatment early, while rich people had better adherence and overall treatment outcomes. Decomposition revealed that occupation and education played important roles in inequality in ART access, adherence, and treatment outcomes Conclusion The findings suggested that health services should be integrated into the ART regimen. Furthermore, occupational orientation and training courses should be provided to reduce inequality in ART access, adherence, and treatment outcomes. PMID:28005937

Crossbar nanoarchitectonics of the crosslinked self-assembled monolayer

PubMed Central

2014-01-01

A bottom-up approach was devised to build a crossbar device using the crosslinked SAM of the 5,5′-bis (mercaptomethyl)-2,2′-bipyridine-Ni2+ (BPD- Ni2+) on a gold surface. To avoid metal diffusion through the organic film, the author used (i) nanoscale bottom electrodes to reduce the probability of defects on the bottom electrodes and (ii) molecular crosslinked technology to avoid metal diffusion through the SAMs. The properties of the crosslinked self-assembled monolayer were determined by XPS. I-V characteristics of the device show thermally activated hopping transport. The implementation of this type of architecture will open up new vistas for a new class of devices for transport, storage, and computing. PMID:24994952

Distributed Memory Breadth-First Search Revisited: Enabling Bottom-Up Search

DTIC Science & Technology

2013-01-03

Jun. 1972. [2] W. McLendon III, B. Hendrickson, S . J. Plimpton , and L. Rauchwerger, “Finding strongly connected components in distributed graphs,” J...Breadth-First Search Revisited: Enabling Bottom-Up Search 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR( S ) 5d. PROJECT...NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME( S ) AND ADDRESS(ES) University of California at Berkeley,Electrical

Density- and trait-mediated top-down effects modify bottom-up control of a highly endemic tropical aquatic food web

Treesearch

C. M. Dalton; A. Mokiao-Lee; T. S. Sakihara; M. G. Weber; C. A. Roco; Z. Han; B. Dudley; R. A. MacKenzie; N. G. Hairston Jr.

2013-01-01

Benthic invertebrates mediate bottom–up and top–down influences in aquatic food webs, and changes in the abundance or traits of invertebrates can alter the strength of top–down effects. Studies assessing the role of invertebrate abundance and behavior as controls on food web structure are rare at the whole ecosystem scale. Here we use a comparative approach to...

The Civil-Military Gap in the United States. Does It Exist, Why, and Does It Matter?

DTIC Science & Technology

2007-01-01

and/or the general public. Based on this framework, our analysis then compares the char- acteristics of military and civilian respondents using a...armed forces, three major force structure reviews (1990 Base Force, 1993 Bottom-Up Review, 1997 Quadrennial Defense Review) took place in the space...Defense Planning in a Decade of Change: Lessons from the Base Force, Bottom-Up Review, and Quadrennial Defense Review, Santa Monica, CA: RAND

A New Global Anthropogenic SO2 Emission Inventory for the Last Decade: A Mosaic of Satellite-derived and Bottom-up Emissions

NASA Astrophysics Data System (ADS)

Liu, F.; Joiner, J.; Choi, S.; Krotkov, N. A.; Li, C.; Fioletov, V. E.; McLinden, C. A.

2017-12-01

Sulfur dioxide (SO2) measurements from the Ozone Monitoring Instrument (OMI) satellite sensor have been used to detect emissions from large point sources using an innovative estimation technique. Emissions from about 500 sources have been quantified individually based on OMI observations, accounting for about a half of total reported anthropogenic SO2 emissions. We developed a new emission inventory, OMI-HTAP, by combining these OMI-based emission estimates and the conventional bottom-up inventory. OMI-HTAP includes OMI-based estimates for over 400 point sources and is gap-filled with the emission grid map of the latest available global bottom-up emission inventory (HTAP v2.2) for the rest of sources. We have evaluated the OMI-HTAP inventory by performing simulations with the Goddard Earth Observing System version 5 (GEOS-5) model. The GEOS-5 simulated SO2 concentrations driven by both the HTAP and the OMI-HTAP inventory were compared against in-situ and satellite measurements. Results show that the OMI-HTAP inventory improves the model agreement with observations, in particular over the US, India and the Middle East. Additionally, simulations with the OMI-HTAP inventory capture the major trends of anthropogenic SO2 emissions over the world and highlight the influence of missing sources in the bottom-up inventory.

Age-related decline in bottom-up processing and selective attention in the very old.

PubMed

Zhuravleva, Tatyana Y; Alperin, Brittany R; Haring, Anna E; Rentz, Dorene M; Holcomb, Philip J; Daffner, Kirk R

2014-06-01

Previous research demonstrating age-related deficits in selective attention have not included old-old adults, an increasingly important group to study. The current investigation compared event-related potentials in 15 young-old (65-79 years old) and 23 old-old (80-99 years old) subjects during a color-selective attention task. Subjects responded to target letters in a specified color (Attend) while ignoring letters in a different color (Ignore) under both low and high loads. There were no group differences in visual acuity, accuracy, reaction time, or latency of early event-related potential components. The old-old group showed a disruption in bottom-up processing, indexed by a substantially diminished posterior N1 (smaller amplitude). They also demonstrated markedly decreased modulation of bottom-up processing based on selected visual features, indexed by the posterior selection negativity (SN), with similar attenuation under both loads. In contrast, there were no group differences in frontally mediated attentional selection, measured by the anterior selection positivity (SP). There was a robust inverse relationship between the size of the SN and SP (the smaller the SN, the larger the SP), which may represent an anteriorly supported compensatory mechanism. In the absence of a decline in top-down modulation indexed by the SP, the diminished SN may reflect age-related degradation of early bottom-up visual processing in old-old adults.

The Effect of a Multi-Level Intervention on the Initiation of Antiretroviral Therapy (ART) among HIV-Infected Men Who Inject Drugs and Were Diagnosed Late in Thai Nguyen, Vietnam

PubMed Central

Zelaya, Carla E.; Le Minh, Nguyen; Lau, Bryan; Latkin, Carl A.; Viet Ha, Tran; Minh Quan, Vu; Mo, Thi Tran; Sripaipan, Teerada; Davis, Wendy W.; Celentano, David D.; Frangakis, Constantine; Go, Vivian F.

2016-01-01

Background In Vietnam, an estimated 256,000 people are living with HIV, and 58% of HIV-infections reported are among people who inject drugs (PWID). While antiretroviral therapy (ART) is widely available in Vietnam, marginalized hard-to-reach male PWID, demonstrate significantly reduced and delayed access to ART. Methods We investigated the effect of a randomized four-arm multi-level intervention trial on ART initiation among male PWID. Our analysis was conducted among a subset of trial participants (n = 136), who were newly diagnosed as HIV-infected, treatment naïve, and eligible for ART (baseline late diagnosis). The trial arms included: 1, standard of care (HIV testing and counseling); 2, structural-level intervention (door-to-door communications and community video screenings); 3, individual-level intervention (counseling plus group support); and 4, individual-level plus structural-level intervention. In a time-to-event analysis, we used a non-parametric approach for competing risks to estimate cumulative incidence function (CIF) for ART initiation (event of interest) by arm and the difference in CIF for each trial arm as compared to Arm 1. Follow-up was conducted at 6, 12, 18 and 24 months. Data collection occurred from 2009 to 2013. Findings By 24-months, 61.0% initiated ART, and 30.9% had died prior to ART initiation. In the first 6 months, participants in arm 4 (individual plus community intervention) had a 28% (95% confidence interval (CI): 6–50%) increased probability of initiating ART. Despite increasing coverage of ART in all arms throughout follow-up, participants in arm 4 retained a 31% (95% CI: 5–56%) increased probability of initiating ART. The individual and community components of the intervention were only effective when delivered together. Conclusions Marginalized, hard-to-reach men, who do not routinely engage in HIV services, and therefore come into care late, may benefit significantly from both individual counseling and group support, in combination with community-focused stigma reduction, when being referred and attempting to initiate urgently needed ART. PMID:27579772

The Problem of Late ART initiation in Sub-Saharan Africa: A Transient Aspect of Scale-up or a Long-term Phenomenon?

PubMed Central

Lahuerta, Maria; Ue, Frances; Hoffman, Susie; Elul, Batya; Kulkarni, Sarah Gorrell; Wu, Yingfeng; Nuwagaba-Biribonwoha, Harriet; Remien, Robert H.; Sadr, Wafaa El; Nash, Denis

2013-01-01

Efforts to scale-up HIV care and treatment have been successful at initiating large numbers of patients onto antiretroviral therapy (ART), although persistent challenges remain to optimizing scale-up effectiveness in both resource-rich and resource-limited settings. Among the most important are very high rates of ART initiation in the advanced stages of HIV disease, which in turn drive morbidity, mortality, and onward transmission of HIV. With a focus on sub-Saharan Africa, this review article presents a conceptual framework for a broader discussion of the persistent problem of late ART initiation, including a need for more focus on the upstream precursors (late HIV diagnosis and late enrollment into HIV care) and their determinants. Without additional research and identification of multilevel interventions that successfully promote earlier initiation of ART, the problem of late ART initiation will persist, significantly undermining the long-term impact of HIV care scale-up on reducing mortality and controlling the HIV epidemic. PMID:23377739

Malawi's contribution to "3 by 5": achievements and challenges.

PubMed

Libamba, Edwin; Makombe, Simon D; Harries, Anthony D; Schouten, Erik J; Yu, Joseph Kwong-Leung; Pasulani, Olesi; Mhango, Eustice; Aberle-Grasse, John; Hochgesang, Mindy; Limbambala, Eddie; Lungu, Douglas

2007-02-01

Many resource-poor countries have started scaling up antiretroviral therapy (ART). While reports from individual clinics point to successful implementation, there is limited information about progress in government institutions at a national level. Malawi started national ART scale-up in 2004 using a structured approach. There is a focus on one generic, fixed-dose combination treatment with stavudine, lamivudine and nevirapine. Treatment is delivered free of charge to eligible patients with HIV and there is a standardized system for recruiting patients, monthly follow-up, registration, monitoring and reporting of cases and outcomes. All treatment sites receive quarterly supervision and evaluation. In January 2004, there were nine public sector facilities delivering ART to an estimated 4 000 patients. By December 2005, there were 60 public sector facilities providing free ART to 37,840 patients using national standardized systems. Analysis of quarterly cohort treatment outcomes at 12 months showed 80% of patients were alive, 10% dead, 9% lost to follow-up and 1% had stopped treatment. Achievements were the result of clear national ART guidelines, implementing partners working together, an intensive training schedule focused on clinical officers and nurses, a structured system of accrediting facilities for ART delivery, quarterly supervision and monitoring, and no stock-outs of antiretroviral drugs. The main challenges are to increase the numbers of children, pregnant women and patients with tuberculosis being started on ART, and to avert high early mortality and losses to follow-up. The capacity of the health sector to cope with escalating case loads and to scale up prevention alongside treatment will determine the future success of ART delivery in Malawi.

24 CFR 3285.804 - Bottom board repair.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Bottom board repair. 3285.804 Section 3285.804 Housing and Urban Development Regulations Relating to Housing and Urban Development... URBAN DEVELOPMENT MODEL MANUFACTURED HOME INSTALLATION STANDARDS Exterior and Interior Close-Up § 3285...

Depth investigation of rapid sand filters for drinking water production reveals strong stratification in nitrification biokinetic behavior.

PubMed

Tatari, K; Smets, B F; Albrechtsen, H-J

2016-09-15

The biokinetic behavior of NH4(+) removal was investigated at different depths of a rapid sand filter treating groundwater for drinking water preparation. Filter materials from the top, middle and bottom layers of a full-scale filter were exposed to various controlled NH4(+) loadings in a continuous-flow lab-scale assay. NH4(+) removal capacity, estimated from short term loading up-shifts, was at least 10 times higher in the top than in the middle and bottom filter layers, consistent with the stratification of Ammonium Oxidizing Bacteria (AOB). AOB density increased consistently with the NH4(+) removal rate, indicating their primarily role in nitrification under the imposed experimental conditions. The maximum AOB cell specific NH4(+) removal rate observed at the bottom was at least 3 times lower compared to the top and middle layers. Additionally, a significant up-shift capacity (4.6 and 3.5 times) was displayed from the top and middle layers, but not from the bottom layer at increased loading conditions. Hence, AOB with different physiological responses were active at the different depths. The biokinetic analysis predicted that despite the low NH4(+) removal capacity at the bottom layer, the entire filter is able to cope with a 4-fold instantaneous loading increase without compromising the effluent NH4(+). Ultimately, this filter up-shift capacity was limited by the density of AOB and their biokinetic behavior, both of which were strongly stratified. Copyright © 2016 Elsevier Ltd. All rights reserved.

Bottom-up modeling of damage in heterogeneous quasi-brittle solids

NASA Astrophysics Data System (ADS)

Rinaldi, Antonio

2013-03-01

The theoretical modeling of multisite cracking in quasi-brittle materials is a complex damage problem, hard to model with traditional methods of fracture mechanics due to its multiscale nature and to strain localization induced by microcracks interaction. Macroscale "effective" elastic models can be conveniently applied if a suitable Helmholtz free energy function is identified for a given material scenario. Del Piero and Truskinovsky (Continuum Mech Thermodyn 21:141-171, 2009), among other authors, investigated macroscale continuum solutions capable of matching—in a top-down view—the phenomenology of the damage process for quasi-brittle materials regardless of the microstructure. On the contrary, this paper features a physically based solution method that starts from the direct consideration of the microscale properties and, in a bottom-up view, recovers a continuum elastic description. This procedure is illustrated for a simple one-dimensional problem of this type, a bar modeled stretched by an axial displacement, where the bar is modeled as a 2D random lattice of decohesive spring elements of finite strength. The (microscale) data from simulations are used to identify the "exact" (macro-) damage parameter and to build up the (macro-) Helmholtz function for the equivalent elastic model, bridging the macroscale approach by Del Piero and Truskinovsky. The elastic approach, coupled with microstructural knowledge, becomes a more powerful tool to reproduce a broad class of macroscopic material responses by changing the convexity-concavity of the Helmholtz energy. The analysis points out that mean-field statistics are appropriate prior to damage localization but max-field statistics are better suited in the softening regime up to failure, where microstrain fluctuation needs to be incorporated in the continuum model. This observation is of consequence to revise mean-field damage models from literature and to calibrate Nth gradient continuum models.

Bottom-up laboratory testing of the DKIST Visible Broadband Imager (VBI)

NASA Astrophysics Data System (ADS)

Ferayorni, Andrew; Beard, Andrew; Cole, Wes; Gregory, Scott; Wöeger, Friedrich

2016-08-01

The Daniel K. Inouye Solar Telescope (DKIST) is a 4-meter solar observatory under construction at Haleakala, Hawaii [1]. The Visible Broadband Imager (VBI) is a first light instrument that will record images at the highest possible spatial and temporal resolution of the DKIST at a number of scientifically important wavelengths [2]. The VBI is a pathfinder for DKIST instrumentation and a test bed for developing processes and procedures in the areas of unit, systems integration, and user acceptance testing. These test procedures have been developed and repeatedly executed during VBI construction in the lab as part of a "test early and test often" philosophy aimed at identifying and resolving issues early thus saving cost during integration test and commissioning on summit. The VBI team recently completed a bottom up end-to-end system test of the instrument in the lab that allowed the instrument's functionality, performance, and usability to be validated against documented system requirements. The bottom up testing approach includes four levels of testing, each introducing another layer in the control hierarchy that is tested before moving to the next level. First the instrument mechanisms are tested for positioning accuracy and repeatability using a laboratory position-sensing detector (PSD). Second the real-time motion controls are used to drive the mechanisms to verify speed and timing synchronization requirements are being met. Next the high-level software is introduced and the instrument is driven through a series of end-to-end tests that exercise the mechanisms, cameras, and simulated data processing. Finally, user acceptance testing is performed on operational and engineering use cases through the use of the instrument engineering graphical user interface (GUI). In this paper we present the VBI bottom up test plan, procedures, example test cases and tools used, as well as results from test execution in the laboratory. We will also discuss the benefits realized through completion of this testing, and share lessons learned from the bottoms up testing process.

Comparing Top-down and Bottom-up Estimates of Methane Emissions across Multiple U.S. Basins Provides Insights into National Oil and Gas Emissions and Mitigation Strategies

NASA Astrophysics Data System (ADS)

Hamburg, S.; Alvarez, R.; Lyon, D. R.; Zavala-Araiza, D.

2016-12-01

Several recent studies quantified regional methane emissions in U.S. oil and gas (O&G) basins using top-down approaches such as airborne mass balance measurements. These studies apportioned total methane emissions to O&G based on hydrocarbon ratios or subtracting bottom-up estimates of other sources. In most studies, top-down estimates of O&G methane emissions exceeded bottom-up emission inventories. An exception is the Barnett Shale Coordinated Campaign, which found agreement between aircraft mass balance estimates and a custom emission inventory. Reconciliation of Barnett Shale O&G emissions depended on two key features: 1) matching the spatial domains of top-down and bottom-up estimates, and 2) accounting for fat-tail sources in site-level emission factors. We construct spatially explicit custom emission inventories for domains with top-down O&G emission estimates in eight major U.S. oil and gas production basins using a variety of data sources including a spatially-allocated U.S. EPA Greenhouse Gas Inventory, the EPA Greenhouse Gas Reporting Program, state emission inventories, and recently published measurement studies. A comparison of top-down and our bottom-up estimates of O&G emissions constrains the gap between these approaches and elucidates regional variability in production-normalized loss rates. A comparison of component-level and site-level emission estimates of production sites in the Barnett Shale region - where comprehensive activity data and emissions estimates are available - indicates that abnormal process conditions contribute about 20% of regional O&G emissions. Combining these two analyses provides insights into the relative importance of different equipment, processes, and malfunctions to emissions in each basin. These data allow us to estimate the U.S. O&G supply chain loss rate, recommend mitigation strategies to reduce emissions from existing infrastructure, and discuss how a similar approach can be applied internationally.

Atmospheric Carbon Tetrachloride: Mysterious Emissions Gap Almost Closed

NASA Astrophysics Data System (ADS)

Liang, Q.; Newman, P. A.; Reimann, S.

2016-12-01

Carbon tetrachloride (CCl4) is a major ozone-depleting substance and its production and consumption is controlled under the Montreal Protocol for emissive uses. The most recent WMO/UNEP Scientific Assessment of Ozone Depletion [WMO, 2014] estimated a 2007-2012 CCl4 bottom-up emission of 1-4 Gg yr-1, based on country-by-country reports to UNEP, vs. a global top-down emissions estimate of 57 Gg yr-1, based on atmospheric measurements. To understand the gap between the top-down and bottom-up emissions estimates, a CCl4 activity was formed under the auspices of the Stratosphere-Troposphere Processes And their Role in Climate (SPARC) project. Several new findings were brought forward by the SPARC CCl4 activity. CCl4 is destroyed in the stratosphere, oceans, and soils. The total lifetime estimate has been increased from 26 to 33 years. The new 33-year total lifetime lowers the top-down emissions estimate to 40 (25-55) Gg yr-1. In addition, a persistent hemispheric difference implies substantial ongoing Northern Hemisphere emissions, yielding an independent emissions estimate of 30 Gg yr-1. The combination of these two yields an emissions estimate of 35 Gg yr-1. Regional estimates have been made for Australia, North America, East Asia, and Western Europe. The sum of these estimates results in emissions of 21 Gg yr-1, albeit this does not include all regions of the world. Four bottom-up CCl4 emissions pathways have been identified, i.e., fugitive, unreported non-feedstock, unreported inadvertent, and legacy emissions. The new industrial bottom-up emissions estimate includes emissions from chloromethanes plants (13 Gg yr-1) and feedstock fugitive emissions (2 Gg yr-1). When combined with legacy emissions and unreported inadvertent emissions ( 10 Gg yr-1), the total global emissions are 20±5 Gg yr-1. While the new bottom-up value is still less than the aggregated top-down values, these estimates reconcile the CCl4 budget discrepancy when considered at the edges of their uncertainties.

Nested Global Inversion for the Carbon Flux Distribution in Canada and USA from 1994 to 2003

NASA Astrophysics Data System (ADS)

Chen, J. M.; Deng, F.; Ishizawa, M.; Ju, W.; Mo, G.; Chan, D.; Higuchi, K.; Maksyutov, S.

2007-12-01

Based on TransCom inverse modeling for 22 global regions, we developed a nested global inversion system for estimating carbon fluxes of 30 regions in North America (2 of the 22 regions are divided into 30). Irregular boundaries of these 30 regions are delineated based on ecosystem types and provincial/state borders. Synthesis Bayesian inversion is conducted in monthly steps using CO2 concentration measurements at 88 coastal and continental stations of the globe for the 1994-2003 period (NOAA GlobalView database). Responses of these stations to carbon fluxes from the 50 regions are simulated using the transport model of National Institute for Environmental Studies of Japan and reanalysis wind fields of the National Centers for Environmental Prediction (NCEP). Terrestrial carbon flux fields modeled using BEPS and Biome-BGC driven by NCEP reanalysis meteorological data are used as two different a priori to constrain the inversion. The inversion (top- down) results are compared with remote sensing-based ecosystem modeling (bottom-up) results in Canada's forests and wetlands. There is a broad consistency in the spatial pattern of the carbon source and sink distributions obtained using these two independent methods. Both sets of results also indicate that Canada's forests and wetlands are carbon sinks in 1994-2003, but the top-down method produces consistently larger sinks than the bottom-up results. Reasons for this discrepancy may lie in both methods, and several issues are identified for further investigation.

Measurements of traffic emissions over a medium-sized city using long-path measurements and comparison against bottom-up city estimates

NASA Astrophysics Data System (ADS)

Waxman, E.; Cossel, K.; Truong, G. W.; Giorgetta, F.; Swann, W.; Coddington, I.; Newbury, N.

2017-12-01

Understanding emissions from cities is increasingly important as a growing fraction of the world's population moves to cities. Here we use a novel technology, dual frequency comb spectroscopy, to measure city emissions using a long outdoor open path. We simultaneously measured CO2, CH4, and H2O over the city of Boulder, Colorado and over a clean-air reference path for two months in the fall of 2016. Because of the spatial coverage of our measurements, the layout of the city and power plant locations, and the predominant wind direction, our measurements primarily pick up vehicle emissions. We choose two days with consistent CO2 enhancements over the city relative to the reference path and use a simple 0-D box model to calculate city emissions for these days. We scale these up to annual emissions and compare our measurements with the City of Boulder bottom-up vehicle emissions inventory based on total vehicle miles traveled, fuel efficiency, and vehicle type distribution. We find good agreement (within about a factor of two) between our top-down measurements and the city's bottom-up inventory value.

Sediment unmixing using detrital geochronology

USGS Publications Warehouse

Sharman, Glenn R.; Johnstone, Samuel

2017-01-01

Sediment mixing within sediment routing systems can exert a strong influence on the preservation of provenance signals that yield insight into the influence of environmental forcings (e.g., tectonism, climate) on the earth’s surface. Here we discuss two approaches to unmixing detrital geochronologic data in an effort to characterize complex changes in the sedimentary record. First we summarize ‘top-down’ mixing, which has been successfully employed in the past to characterize the different fractions of prescribed source distributions (‘parents’) that characterize a derived sample or set of samples (‘daughters’). Second we propose the use of ‘bottom-up’ methods, previously used primarily for grain size distributions, to model parent distributions and the abundances of these parents within a set of daughters. We demonstrate the utility of both top-down and bottom-up approaches to unmixing detrital geochronologic data within a well-constrained sediment routing system in central California. Use of a variety of goodness-of-fit metrics in top-down modeling reveals the importance of considering the range of allowable mixtures over any single best-fit mixture calculation. Bottom-up modeling of 12 daughter samples from beaches and submarine canyons yields modeled parent distributions that are remarkably similar to those expected from the geologic context of the sediment-routing system. In general, mixture modeling has potential to supplement more widely applied approaches in comparing detrital geochronologic data by casting differences between samples as differing proportions of geologically meaningful end-member provenance categories.

Early Mortality in Adults Initiating Antiretroviral Therapy (ART) in Low- and Middle-Income Countries (LMIC): A Systematic Review and Meta-Analysis

PubMed Central

Gupta, Amita; Nadkarni, Girish; Yang, Wei-Teng; Chandrasekhar, Aditya; Gupte, Nikhil; Bisson, Gregory P.; Hosseinipour, Mina; Gummadi, Naveen

2011-01-01

Background We systematically reviewed observational studies of early mortality post-antiretroviral therapy (ART) initiation in low- and middle-income countries (LMIC) in Asia, Africa, and Central and South America, as defined by the World Bank, to summarize what is known. Methods and Findings Studies published in English between January 1996 and December 2010 were searched in Medline and EMBASE. Three independent reviewers examined studies of mortality within one year post-ART. An article was included if the study was conducted in a LMIC, participants were initiating ART in a non-clinical trial setting and were ≥15 years. Fifty studies were included; 38 (76%) from sub-Saharan Africa (SSA), 5 (10%) from Asia, 2 (4%) from the Americas, and 5 (10%) were multi-regional. Median follow-up time and pre-ART CD4 cell count ranged from 3–55 months and 11–192 cells/mm3, respectively. Loss-to-follow-up, reported in 40 (80%) studies, ranged from 0.3%–27%. Overall, SSA had the highest pooled 12-month mortality probability of 0.17 (95% CI 0.11–0.24) versus 0.11 (95% CI 0.10–0.13) for Asia, and 0.07 (95% CI 0.007–0.20) for the Americas. Of 14 (28%) studies reporting cause-specific mortality, tuberculosis (TB) (5%–44%), wasting (5%–53%), advanced HIV (20%–37%), and chronic diarrhea (10%–25%) were most common. Independent factors associated with early mortality in 30 (60%) studies included: low baseline CD4 cell count, male sex, advanced World Health Organization clinical stage, low body mass index, anemia, age greater than 40 years, and pre-ART quantitative HIV RNA. Conclusions Significant heterogeneity in outcomes and in methods of reporting outcomes exist among published studies evaluating mortality in the first year after ART initiation in LMIC. Early mortality rates are highest in SSA, and opportunistic illnesses such as TB and wasting syndrome are the most common reported causes of death. Strategies addressing modifiable risk factors associated with early death are urgently needed. PMID:22220193

Controlled Growth of Ceria Nanoarrays on Anatase Titania Powder: A Bottom-up Physical Picture

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

Kim, Hyun You; Hybertsen, Mark S.; Liu, Ping

The leading edge of catalysis research motivates physical understanding of the growth of nanoscale oxide structures on different supporting oxide materials that are themselves also nanostructured. This research opens up for consideration a diverse range of facets on the support material, versus the single facet typically involved in wide-area growth of thin films. In this paper, we study the growth of ceria nanoarchitectures on practical anatase titania powders as a showcase inspired by recent experiments. Density functional theory (DFT)-based methods are employed to characterize and rationalize the broad array of low energy nanostructures that emerge. Using a bottom-up approach, wemore » are able to identify and characterize the underlying mechanisms for the facet-dependent growth of various ceria motifs on anatase titania based on formation energy. These motifs include 0D clusters, 1D chains, 2D plates, and 3D nanoparticles. Finally, the ceria growth mode and morphology are determined by the interplay of several factors including the role of the common cation valence, the interface template effect for different facets of the anatase support, enhanced ionic binding for more compact ceria motifs, and the local structural flexibility of oxygen ions in bridging the interface between anatase and ceria structures.« less

Controlled Growth of Ceria Nanoarrays on Anatase Titania Powder: A Bottom-up Physical Picture

DOE PAGES

Kim, Hyun You; Hybertsen, Mark S.; Liu, Ping

2016-12-05

The leading edge of catalysis research motivates physical understanding of the growth of nanoscale oxide structures on different supporting oxide materials that are themselves also nanostructured. This research opens up for consideration a diverse range of facets on the support material, versus the single facet typically involved in wide-area growth of thin films. In this paper, we study the growth of ceria nanoarchitectures on practical anatase titania powders as a showcase inspired by recent experiments. Density functional theory (DFT)-based methods are employed to characterize and rationalize the broad array of low energy nanostructures that emerge. Using a bottom-up approach, wemore » are able to identify and characterize the underlying mechanisms for the facet-dependent growth of various ceria motifs on anatase titania based on formation energy. These motifs include 0D clusters, 1D chains, 2D plates, and 3D nanoparticles. Finally, the ceria growth mode and morphology are determined by the interplay of several factors including the role of the common cation valence, the interface template effect for different facets of the anatase support, enhanced ionic binding for more compact ceria motifs, and the local structural flexibility of oxygen ions in bridging the interface between anatase and ceria structures.« less

Vertical heterostructures of MoS2 and graphene nanoribbons grown by two-step chemical vapor deposition for high-gain photodetectors.

PubMed

Yunus, Rozan Mohamad; Endo, Hiroko; Tsuji, Masaharu; Ago, Hiroki

2015-10-14

Heterostructures of two-dimensional (2D) layered materials have attracted growing interest due to their unique properties and possible applications in electronics, photonics, and energy. Reduction of the dimensionality from 2D to one-dimensional (1D), such as graphene nanoribbons (GNRs), is also interesting due to the electron confinement effect and unique edge effects. Here, we demonstrate a bottom-up approach to grow vertical heterostructures of MoS2 and GNRs by a two-step chemical vapor deposition (CVD) method. Single-layer GNRs were first grown by ambient pressure CVD on an epitaxial Cu(100) film, followed by the second CVD process to grow MoS2 over the GNRs. The MoS2 layer was found to grow preferentially on the GNR surface, while the coverage could be further tuned by adjusting the growth conditions. The MoS2/GNR nanostructures show clear photosensitivity to visible light with an optical response much higher than that of a 2D MoS2/graphene heterostructure. The ability to grow a novel 1D heterostructure of layered materials by a bottom-up CVD approach will open up a new avenue to expand the dimensionality of the material synthesis and applications.